Merge branch 'maxmsgsz' into bm_msgsz

.gitignore

@@ -32,7 +32,7 @@ coverage
 # python compiled objects
 *.pyc
 
-#eclipse project files
+# eclipse project files
 .cproject
 .project
 .settings
@@ -111,3 +111,6 @@ bazel-genfiles
 bazel-grpc
 bazel-out
 bazel-testlogs
+
+# Debug output
+gdb.txt

BUILD

@@ -499,6 +499,8 @@ grpc_cc_library(
         "src/core/lib/slice/percent_encoding.c",
         "src/core/lib/slice/slice.c",
         "src/core/lib/slice/slice_buffer.c",
+        "src/core/lib/slice/slice_hash_table.c",
+        "src/core/lib/slice/slice_intern.c",
         "src/core/lib/slice/slice_string_helpers.c",
         "src/core/lib/surface/alarm.c",
         "src/core/lib/surface/api_trace.c",
@@ -520,12 +522,13 @@ grpc_cc_library(
         "src/core/lib/surface/version.c",
         "src/core/lib/transport/byte_stream.c",
         "src/core/lib/transport/connectivity_state.c",
-        "src/core/lib/transport/mdstr_hash_table.c",
+        "src/core/lib/transport/error_utils.c",
         "src/core/lib/transport/metadata.c",
         "src/core/lib/transport/metadata_batch.c",
         "src/core/lib/transport/pid_controller.c",
         "src/core/lib/transport/service_config.c",
         "src/core/lib/transport/static_metadata.c",
+        "src/core/lib/transport/status_conversion.c",
         "src/core/lib/transport/timeout_encoding.c",
         "src/core/lib/transport/transport.c",
         "src/core/lib/transport/transport_op_string.c",
@@ -555,6 +558,7 @@ grpc_cc_library(
         "src/core/lib/iomgr/endpoint.h",
         "src/core/lib/iomgr/endpoint_pair.h",
         "src/core/lib/iomgr/error.h",
+        "src/core/lib/iomgr/error_internal.h",
         "src/core/lib/iomgr/ev_epoll_linux.h",
         "src/core/lib/iomgr/ev_poll_posix.h",
         "src/core/lib/iomgr/ev_posix.h",
@@ -607,6 +611,7 @@ grpc_cc_library(
         "src/core/lib/json/json_reader.h",
         "src/core/lib/json/json_writer.h",
         "src/core/lib/slice/percent_encoding.h",
+        "src/core/lib/slice/slice_hash_table.h",
         "src/core/lib/slice/slice_internal.h",
         "src/core/lib/slice/slice_string_helpers.h",
         "src/core/lib/surface/api_trace.h",
@@ -618,16 +623,19 @@ grpc_cc_library(
         "src/core/lib/surface/completion_queue.h",
         "src/core/lib/surface/event_string.h",
         "src/core/lib/surface/init.h",
+        "src/core/lib/surface/validate_metadata.h",
         "src/core/lib/surface/lame_client.h",
         "src/core/lib/surface/server.h",
         "src/core/lib/transport/byte_stream.h",
         "src/core/lib/transport/connectivity_state.h",
-        "src/core/lib/transport/mdstr_hash_table.h",
+        "src/core/lib/transport/error_utils.h",
+        "src/core/lib/transport/http2_errors.h",
         "src/core/lib/transport/metadata.h",
         "src/core/lib/transport/metadata_batch.h",
         "src/core/lib/transport/pid_controller.h",
         "src/core/lib/transport/service_config.h",
         "src/core/lib/transport/static_metadata.h",
+        "src/core/lib/transport/status_conversion.h",
         "src/core/lib/transport/timeout_encoding.h",
         "src/core/lib/transport/transport.h",
         "src/core/lib/transport/transport_impl.h",
@@ -880,7 +888,6 @@ grpc_cc_library(
         "src/core/ext/transport/chttp2/transport/huffsyms.c",
         "src/core/ext/transport/chttp2/transport/incoming_metadata.c",
         "src/core/ext/transport/chttp2/transport/parsing.c",
-        "src/core/ext/transport/chttp2/transport/status_conversion.c",
         "src/core/ext/transport/chttp2/transport/stream_lists.c",
         "src/core/ext/transport/chttp2/transport/stream_map.c",
         "src/core/ext/transport/chttp2/transport/varint.c",
@@ -900,11 +907,9 @@ grpc_cc_library(
         "src/core/ext/transport/chttp2/transport/hpack_encoder.h",
         "src/core/ext/transport/chttp2/transport/hpack_parser.h",
         "src/core/ext/transport/chttp2/transport/hpack_table.h",
-        "src/core/ext/transport/chttp2/transport/http2_errors.h",
         "src/core/ext/transport/chttp2/transport/huffsyms.h",
         "src/core/ext/transport/chttp2/transport/incoming_metadata.h",
         "src/core/ext/transport/chttp2/transport/internal.h",
-        "src/core/ext/transport/chttp2/transport/status_conversion.h",
         "src/core/ext/transport/chttp2/transport/stream_map.h",
         "src/core/ext/transport/chttp2/transport/varint.h",
     ],

INSTALL.md

@@ -61,49 +61,45 @@ gRPC C Core library.
 There are several ways to build under Windows, of varying complexity depending
 on experience with the tools involved.
 
-<!--
-###Visual Studio
+###Pre-generated Visual Studio solution
 
-Versions 2013 and 2015 are both supported. You can use [their respective
-community
-editions](https://www.visualstudio.com/en-us/downloads/download-visual-studio-vs.aspx).
-
-Building the C Core:
-- Open [grpc.sln](https://github.com/grpc/grpc/blob/master/vsprojects/grpc.sln).
-- Select your build target.
-- Build the `grpc` project.
+The pre-generated VS projects & solution are checked into the repository under the [vsprojects](/vsprojects) directory.
+  
+###Building using CMake (with BoringSSL)
+- Install [CMake](https://cmake.org/download/).
+- Install [Active State Perl](http://www.activestate.com/activeperl/) (`choco install activeperl`)
+- Install [Ninja](https://ninja-build.org/) (`choco install ninja`)
+- Install [Go](https://golang.org/dl/) (`choco install golang`)
+- Install [yasm](http://yasm.tortall.net/) and add it to `PATH` (`choco install yasm`)
+- Run these commands in the repo root directory
+```
+> md .build
+> cd .build
+> call "%VS140COMNTOOLS%..\..\VC\vcvarsall.bat" x64
+> cmake .. -GNinja -DCMAKE_BUILD_TYPE=Release
+> cmake --build .
+```
+NOTE: Currently you can only use Ninja to build using cmake on Windows (because of the boringssl dependency).
 
-Building the C++ runtime:
-- You need [CMake](https://cmake.org/) on your path to build protobuf (see below
-  for building using solely CMake).
-- Run `vsprojects/build_protos.bat` (needs `cmake.exe` in your path).
-- Open [buildtests_cxx.sln]()
-- Select your build target.
-- build the `grpc++` project.
--->
+###msys2 (with mingw)
 
-###msys2
+The Makefile (and source code) should support msys2's mingw32 and mingw64
+compilers. Building with msys2's native compiler is also possible, but
+difficult.
 
 This approach requires having [msys2](https://msys2.github.io/) installed.
+  
+```
+# Install prerequisites
+MSYS2$ pacman -S autoconf automake gcc libtool mingw-w64-x86_64-toolchain perl pkg-config zlib
+MSYS2$ pacman -S mingw-w64-x86_64-gflags
+```
 
-- The Makefile (and source code) should support msys2's mingw32 and mingw64
-  compilers. Building with msys2's native compiler is also possible, but
-  difficult.
-- The Makefile is expecting the Windows versions of OpenSSL (see
-  https://slproweb.com/products/Win32OpenSSL.html). It's also possible to build
-  the Windows version of OpenSSL from scratch. The output should be `libeay32`
-  and `ssleay32`.
-- If you are not installing the above files under msys2's path, you may specify
-  it, for instance, in the following way:
-  ```CPPFLAGS=”-I/c/OpenSSL-Win32/include” LDFLAGS=”-L/c/OpenSSL-Win32/lib” make static_c```
-- [protobuf3](https://github.com/google/protobuf/blob/master/src/README.md#c-installation---windows)
-  must be installed on the msys2 path.
-
-###Cmake (experimental)
+```
+# From mingw shell
+MINGW64$ export CPPFLAGS="-D_WIN32_WINNT=0x0600"
+MINGW64$ make
+```
 
-- Install [CMake](https://cmake.org/download/).
-- Run it over [grpc's
-  CMakeLists.txt](https://github.com/grpc/grpc/blob/master/CMakeLists.txt) to
-  generate "projects" for your compiler.
-- Build with your compiler of choice. The generated build files should have the
-  protobuf3 dependency baked in.
+NOTE: While most of the make targets are buildable under Mingw, some haven't been ported to Windows yet
+and may fail to build (mostly trying to include POSIX headers not available on Mingw).

Makefile

@@ -95,56 +95,6 @@ LDXX_opt = $(DEFAULT_CXX)
 CPPFLAGS_opt = -O2
 DEFINES_opt = NDEBUG
 
-VALID_CONFIG_asan-trace-cmp = 1
-REQUIRE_CUSTOM_LIBRARIES_asan-trace-cmp = 1
-CC_asan-trace-cmp = clang
-CXX_asan-trace-cmp = clang++
-LD_asan-trace-cmp = clang
-LDXX_asan-trace-cmp = clang++
-CPPFLAGS_asan-trace-cmp = -O0 -fsanitize-coverage=edge -fsanitize-coverage=trace-cmp -fsanitize=address -fno-omit-frame-pointer -Wno-unused-command-line-argument -DGPR_NO_DIRECT_SYSCALLS
-LDFLAGS_asan-trace-cmp = -fsanitize=address
-DEFINES_asan-trace-cmp += GRPC_TEST_SLOWDOWN_BUILD_FACTOR=3
-
-VALID_CONFIG_dbg = 1
-CC_dbg = $(DEFAULT_CC)
-CXX_dbg = $(DEFAULT_CXX)
-LD_dbg = $(DEFAULT_CC)
-LDXX_dbg = $(DEFAULT_CXX)
-CPPFLAGS_dbg = -O0
-DEFINES_dbg = _DEBUG DEBUG
-
-VALID_CONFIG_easan = 1
-REQUIRE_CUSTOM_LIBRARIES_easan = 1
-CC_easan = clang
-CXX_easan = clang++
-LD_easan = clang
-LDXX_easan = clang++
-CPPFLAGS_easan = -O0 -fsanitize-coverage=edge -fsanitize=address -fno-omit-frame-pointer -Wno-unused-command-line-argument -DGPR_NO_DIRECT_SYSCALLS
-LDFLAGS_easan = -fsanitize=address
-DEFINES_easan = _DEBUG DEBUG GRPC_EXECUTION_CONTEXT_SANITIZER
-DEFINES_easan += GRPC_TEST_SLOWDOWN_BUILD_FACTOR=3
-
-VALID_CONFIG_asan = 1
-REQUIRE_CUSTOM_LIBRARIES_asan = 1
-CC_asan = clang
-CXX_asan = clang++
-LD_asan = clang
-LDXX_asan = clang++
-CPPFLAGS_asan = -O0 -fsanitize-coverage=edge -fsanitize=address -fno-omit-frame-pointer -Wno-unused-command-line-argument -DGPR_NO_DIRECT_SYSCALLS
-LDFLAGS_asan = -fsanitize=address
-DEFINES_asan += GRPC_TEST_SLOWDOWN_BUILD_FACTOR=3
-
-VALID_CONFIG_msan = 1
-REQUIRE_CUSTOM_LIBRARIES_msan = 1
-CC_msan = clang
-CXX_msan = clang++
-LD_msan = clang
-LDXX_msan = clang++
-CPPFLAGS_msan = -O0 -fsanitize-coverage=edge -fsanitize=memory -fsanitize-memory-track-origins -fno-omit-frame-pointer -DGTEST_HAS_TR1_TUPLE=0 -DGTEST_USE_OWN_TR1_TUPLE=1 -Wno-unused-command-line-argument -fPIE -pie -DGPR_NO_DIRECT_SYSCALLS
-LDFLAGS_msan = -fsanitize=memory -DGTEST_HAS_TR1_TUPLE=0 -DGTEST_USE_OWN_TR1_TUPLE=1 -fPIE -pie $(if $(JENKINS_BUILD),-Wl$(comma)-Ttext-segment=0x7e0000000000,)
-DEFINES_msan = NDEBUG
-DEFINES_msan += GRPC_TEST_SLOWDOWN_BUILD_FACTOR=4
-
 VALID_CONFIG_basicprof = 1
 CC_basicprof = $(DEFAULT_CC)
 CXX_basicprof = $(DEFAULT_CXX)
@@ -173,35 +123,23 @@ CPPFLAGS_asan-noleaks = -O0 -fsanitize-coverage=edge -fsanitize=address -fno-omi
 LDFLAGS_asan-noleaks = -fsanitize=address
 DEFINES_asan-noleaks += GRPC_TEST_SLOWDOWN_BUILD_FACTOR=3
 
-VALID_CONFIG_edbg = 1
-CC_edbg = $(DEFAULT_CC)
-CXX_edbg = $(DEFAULT_CXX)
-LD_edbg = $(DEFAULT_CC)
-LDXX_edbg = $(DEFAULT_CXX)
-CPPFLAGS_edbg = -O0
-DEFINES_edbg = _DEBUG DEBUG GRPC_EXECUTION_CONTEXT_SANITIZER
-
-VALID_CONFIG_ubsan = 1
-REQUIRE_CUSTOM_LIBRARIES_ubsan = 1
-CC_ubsan = clang
-CXX_ubsan = clang++
-LD_ubsan = clang
-LDXX_ubsan = clang++
-CPPFLAGS_ubsan = -O0 -fsanitize-coverage=edge -fsanitize=undefined,unsigned-integer-overflow -fno-omit-frame-pointer -Wno-unused-command-line-argument -Wvarargs
-LDFLAGS_ubsan = -fsanitize=undefined,unsigned-integer-overflow
-DEFINES_ubsan = NDEBUG
-DEFINES_ubsan += GRPC_TEST_SLOWDOWN_BUILD_FACTOR=1.5
+VALID_CONFIG_asan-trace-cmp = 1
+REQUIRE_CUSTOM_LIBRARIES_asan-trace-cmp = 1
+CC_asan-trace-cmp = clang
+CXX_asan-trace-cmp = clang++
+LD_asan-trace-cmp = clang
+LDXX_asan-trace-cmp = clang++
+CPPFLAGS_asan-trace-cmp = -O0 -fsanitize-coverage=edge -fsanitize-coverage=trace-cmp -fsanitize=address -fno-omit-frame-pointer -Wno-unused-command-line-argument -DGPR_NO_DIRECT_SYSCALLS
+LDFLAGS_asan-trace-cmp = -fsanitize=address
+DEFINES_asan-trace-cmp += GRPC_TEST_SLOWDOWN_BUILD_FACTOR=3
 
-VALID_CONFIG_tsan = 1
-REQUIRE_CUSTOM_LIBRARIES_tsan = 1
-CC_tsan = clang
-CXX_tsan = clang++
-LD_tsan = clang
-LDXX_tsan = clang++
-CPPFLAGS_tsan = -O0 -fsanitize=thread -fno-omit-frame-pointer -Wno-unused-command-line-argument -DGPR_NO_DIRECT_SYSCALLS
-LDFLAGS_tsan = -fsanitize=thread
-DEFINES_tsan = GRPC_TSAN
-DEFINES_tsan += GRPC_TEST_SLOWDOWN_BUILD_FACTOR=5
+VALID_CONFIG_dbg = 1
+CC_dbg = $(DEFAULT_CC)
+CXX_dbg = $(DEFAULT_CXX)
+LD_dbg = $(DEFAULT_CC)
+LDXX_dbg = $(DEFAULT_CXX)
+CPPFLAGS_dbg = -O0
+DEFINES_dbg = _DEBUG DEBUG
 
 VALID_CONFIG_stapprof = 1
 CC_stapprof = $(DEFAULT_CC)
@@ -211,14 +149,14 @@ LDXX_stapprof = $(DEFAULT_CXX)
 CPPFLAGS_stapprof = -O2 -DGRPC_STAP_PROFILER
 DEFINES_stapprof = NDEBUG
 
-VALID_CONFIG_mutrace = 1
-CC_mutrace = $(DEFAULT_CC)
-CXX_mutrace = $(DEFAULT_CXX)
-LD_mutrace = $(DEFAULT_CC)
-LDXX_mutrace = $(DEFAULT_CXX)
-CPPFLAGS_mutrace = -O3 -fno-omit-frame-pointer
-LDFLAGS_mutrace = -rdynamic
-DEFINES_mutrace = NDEBUG
+VALID_CONFIG_gcov = 1
+CC_gcov = gcc
+CXX_gcov = g++
+LD_gcov = gcc
+LDXX_gcov = g++
+CPPFLAGS_gcov = -O0 -fprofile-arcs -ftest-coverage -Wno-return-type
+LDFLAGS_gcov = -fprofile-arcs -ftest-coverage -rdynamic
+DEFINES_gcov = _DEBUG DEBUG GPR_GCOV
 
 VALID_CONFIG_memcheck = 1
 CC_memcheck = $(DEFAULT_CC)
@@ -230,25 +168,57 @@ LDFLAGS_memcheck = -rdynamic
 DEFINES_memcheck = _DEBUG DEBUG
 DEFINES_memcheck += GRPC_TEST_SLOWDOWN_BUILD_FACTOR=10
 
-VALID_CONFIG_etsan = 1
-REQUIRE_CUSTOM_LIBRARIES_etsan = 1
-CC_etsan = clang
-CXX_etsan = clang++
-LD_etsan = clang
-LDXX_etsan = clang++
-CPPFLAGS_etsan = -O0 -fsanitize=thread -fno-omit-frame-pointer -Wno-unused-command-line-argument -DGPR_NO_DIRECT_SYSCALLS
-LDFLAGS_etsan = -fsanitize=thread
-DEFINES_etsan = _DEBUG DEBUG GRPC_EXECUTION_CONTEXT_SANITIZER
-DEFINES_etsan += GRPC_TEST_SLOWDOWN_BUILD_FACTOR=5
+VALID_CONFIG_asan = 1
+REQUIRE_CUSTOM_LIBRARIES_asan = 1
+CC_asan = clang
+CXX_asan = clang++
+LD_asan = clang
+LDXX_asan = clang++
+CPPFLAGS_asan = -O0 -fsanitize-coverage=edge -fsanitize=address -fno-omit-frame-pointer -Wno-unused-command-line-argument -DGPR_NO_DIRECT_SYSCALLS
+LDFLAGS_asan = -fsanitize=address
+DEFINES_asan += GRPC_TEST_SLOWDOWN_BUILD_FACTOR=3
 
-VALID_CONFIG_gcov = 1
-CC_gcov = gcc
-CXX_gcov = g++
-LD_gcov = gcc
-LDXX_gcov = g++
-CPPFLAGS_gcov = -O0 -fprofile-arcs -ftest-coverage -Wno-return-type
-LDFLAGS_gcov = -fprofile-arcs -ftest-coverage -rdynamic
-DEFINES_gcov = _DEBUG DEBUG GPR_GCOV
+VALID_CONFIG_tsan = 1
+REQUIRE_CUSTOM_LIBRARIES_tsan = 1
+CC_tsan = clang
+CXX_tsan = clang++
+LD_tsan = clang
+LDXX_tsan = clang++
+CPPFLAGS_tsan = -O0 -fsanitize=thread -fno-omit-frame-pointer -Wno-unused-command-line-argument -DGPR_NO_DIRECT_SYSCALLS
+LDFLAGS_tsan = -fsanitize=thread
+DEFINES_tsan = GRPC_TSAN
+DEFINES_tsan += GRPC_TEST_SLOWDOWN_BUILD_FACTOR=5
+
+VALID_CONFIG_ubsan = 1
+REQUIRE_CUSTOM_LIBRARIES_ubsan = 1
+CC_ubsan = clang
+CXX_ubsan = clang++
+LD_ubsan = clang
+LDXX_ubsan = clang++
+CPPFLAGS_ubsan = -O0 -fsanitize-coverage=edge -fsanitize=undefined,unsigned-integer-overflow -fno-omit-frame-pointer -Wno-unused-command-line-argument -Wvarargs
+LDFLAGS_ubsan = -fsanitize=undefined,unsigned-integer-overflow
+DEFINES_ubsan = NDEBUG
+DEFINES_ubsan += GRPC_TEST_SLOWDOWN_BUILD_FACTOR=1.5
+
+VALID_CONFIG_msan = 1
+REQUIRE_CUSTOM_LIBRARIES_msan = 1
+CC_msan = clang
+CXX_msan = clang++
+LD_msan = clang
+LDXX_msan = clang++
+CPPFLAGS_msan = -O0 -fsanitize-coverage=edge -fsanitize=memory -fsanitize-memory-track-origins -fno-omit-frame-pointer -DGTEST_HAS_TR1_TUPLE=0 -DGTEST_USE_OWN_TR1_TUPLE=1 -Wno-unused-command-line-argument -fPIE -pie -DGPR_NO_DIRECT_SYSCALLS
+LDFLAGS_msan = -fsanitize=memory -DGTEST_HAS_TR1_TUPLE=0 -DGTEST_USE_OWN_TR1_TUPLE=1 -fPIE -pie $(if $(JENKINS_BUILD),-Wl$(comma)-Ttext-segment=0x7e0000000000,)
+DEFINES_msan = NDEBUG
+DEFINES_msan += GRPC_TEST_SLOWDOWN_BUILD_FACTOR=4
+
+VALID_CONFIG_mutrace = 1
+CC_mutrace = $(DEFAULT_CC)
+CXX_mutrace = $(DEFAULT_CXX)
+LD_mutrace = $(DEFAULT_CC)
+LDXX_mutrace = $(DEFAULT_CXX)
+CPPFLAGS_mutrace = -O3 -fno-omit-frame-pointer
+LDFLAGS_mutrace = -rdynamic
+DEFINES_mutrace = NDEBUG
 
 
 
@@ -944,7 +914,6 @@ census_resource_test: $(BINDIR)/$(CONFIG)/census_resource_test
 census_trace_context_test: $(BINDIR)/$(CONFIG)/census_trace_context_test
 channel_create_test: $(BINDIR)/$(CONFIG)/channel_create_test
 chttp2_hpack_encoder_test: $(BINDIR)/$(CONFIG)/chttp2_hpack_encoder_test
-chttp2_status_conversion_test: $(BINDIR)/$(CONFIG)/chttp2_status_conversion_test
 chttp2_stream_map_test: $(BINDIR)/$(CONFIG)/chttp2_stream_map_test
 chttp2_varint_test: $(BINDIR)/$(CONFIG)/chttp2_varint_test
 client_fuzzer: $(BINDIR)/$(CONFIG)/client_fuzzer
@@ -1052,6 +1021,7 @@ sockaddr_resolver_test: $(BINDIR)/$(CONFIG)/sockaddr_resolver_test
 sockaddr_utils_test: $(BINDIR)/$(CONFIG)/sockaddr_utils_test
 socket_utils_test: $(BINDIR)/$(CONFIG)/socket_utils_test
 ssl_server_fuzzer: $(BINDIR)/$(CONFIG)/ssl_server_fuzzer
+status_conversion_test: $(BINDIR)/$(CONFIG)/status_conversion_test
 tcp_client_posix_test: $(BINDIR)/$(CONFIG)/tcp_client_posix_test
 tcp_posix_test: $(BINDIR)/$(CONFIG)/tcp_posix_test
 tcp_server_posix_test: $(BINDIR)/$(CONFIG)/tcp_server_posix_test
@@ -1295,7 +1265,6 @@ buildtests_c: privatelibs_c \
   $(BINDIR)/$(CONFIG)/census_trace_context_test \
   $(BINDIR)/$(CONFIG)/channel_create_test \
   $(BINDIR)/$(CONFIG)/chttp2_hpack_encoder_test \
-  $(BINDIR)/$(CONFIG)/chttp2_status_conversion_test \
   $(BINDIR)/$(CONFIG)/chttp2_stream_map_test \
   $(BINDIR)/$(CONFIG)/chttp2_varint_test \
   $(BINDIR)/$(CONFIG)/combiner_test \
@@ -1385,6 +1354,7 @@ buildtests_c: privatelibs_c \
   $(BINDIR)/$(CONFIG)/sockaddr_resolver_test \
   $(BINDIR)/$(CONFIG)/sockaddr_utils_test \
   $(BINDIR)/$(CONFIG)/socket_utils_test \
+  $(BINDIR)/$(CONFIG)/status_conversion_test \
   $(BINDIR)/$(CONFIG)/tcp_client_posix_test \
   $(BINDIR)/$(CONFIG)/tcp_posix_test \
   $(BINDIR)/$(CONFIG)/tcp_server_posix_test \
@@ -1640,8 +1610,6 @@ test_c: buildtests_c
 	$(Q) $(BINDIR)/$(CONFIG)/channel_create_test || ( echo test channel_create_test failed ; exit 1 )
 	$(E) "[RUN]     Testing chttp2_hpack_encoder_test"
 	$(Q) $(BINDIR)/$(CONFIG)/chttp2_hpack_encoder_test || ( echo test chttp2_hpack_encoder_test failed ; exit 1 )
-	$(E) "[RUN]     Testing chttp2_status_conversion_test"
-	$(Q) $(BINDIR)/$(CONFIG)/chttp2_status_conversion_test || ( echo test chttp2_status_conversion_test failed ; exit 1 )
 	$(E) "[RUN]     Testing chttp2_stream_map_test"
 	$(Q) $(BINDIR)/$(CONFIG)/chttp2_stream_map_test || ( echo test chttp2_stream_map_test failed ; exit 1 )
 	$(E) "[RUN]     Testing chttp2_varint_test"
@@ -1798,6 +1766,8 @@ test_c: buildtests_c
 	$(Q) $(BINDIR)/$(CONFIG)/sockaddr_utils_test || ( echo test sockaddr_utils_test failed ; exit 1 )
 	$(E) "[RUN]     Testing socket_utils_test"
 	$(Q) $(BINDIR)/$(CONFIG)/socket_utils_test || ( echo test socket_utils_test failed ; exit 1 )
+	$(E) "[RUN]     Testing status_conversion_test"
+	$(Q) $(BINDIR)/$(CONFIG)/status_conversion_test || ( echo test status_conversion_test failed ; exit 1 )
 	$(E) "[RUN]     Testing tcp_client_posix_test"
 	$(Q) $(BINDIR)/$(CONFIG)/tcp_client_posix_test || ( echo test tcp_client_posix_test failed ; exit 1 )
 	$(E) "[RUN]     Testing tcp_posix_test"
@@ -2726,6 +2696,8 @@ LIBGRPC_SRC = \
     src/core/lib/slice/percent_encoding.c \
     src/core/lib/slice/slice.c \
     src/core/lib/slice/slice_buffer.c \
+    src/core/lib/slice/slice_hash_table.c \
+    src/core/lib/slice/slice_intern.c \
     src/core/lib/slice/slice_string_helpers.c \
     src/core/lib/surface/alarm.c \
     src/core/lib/surface/api_trace.c \
@@ -2747,12 +2719,13 @@ LIBGRPC_SRC = \
     src/core/lib/surface/version.c \
     src/core/lib/transport/byte_stream.c \
     src/core/lib/transport/connectivity_state.c \
-    src/core/lib/transport/mdstr_hash_table.c \
+    src/core/lib/transport/error_utils.c \
     src/core/lib/transport/metadata.c \
     src/core/lib/transport/metadata_batch.c \
     src/core/lib/transport/pid_controller.c \
     src/core/lib/transport/service_config.c \
     src/core/lib/transport/static_metadata.c \
+    src/core/lib/transport/status_conversion.c \
     src/core/lib/transport/timeout_encoding.c \
     src/core/lib/transport/transport.c \
     src/core/lib/transport/transport_op_string.c \
@@ -2773,7 +2746,6 @@ LIBGRPC_SRC = \
     src/core/ext/transport/chttp2/transport/huffsyms.c \
     src/core/ext/transport/chttp2/transport/incoming_metadata.c \
     src/core/ext/transport/chttp2/transport/parsing.c \
-    src/core/ext/transport/chttp2/transport/status_conversion.c \
     src/core/ext/transport/chttp2/transport/stream_lists.c \
     src/core/ext/transport/chttp2/transport/stream_map.c \
     src/core/ext/transport/chttp2/transport/varint.c \
@@ -3029,6 +3001,8 @@ LIBGRPC_CRONET_SRC = \
     src/core/lib/slice/percent_encoding.c \
     src/core/lib/slice/slice.c \
     src/core/lib/slice/slice_buffer.c \
+    src/core/lib/slice/slice_hash_table.c \
+    src/core/lib/slice/slice_intern.c \
     src/core/lib/slice/slice_string_helpers.c \
     src/core/lib/surface/alarm.c \
     src/core/lib/surface/api_trace.c \
@@ -3050,12 +3024,13 @@ LIBGRPC_CRONET_SRC = \
     src/core/lib/surface/version.c \
     src/core/lib/transport/byte_stream.c \
     src/core/lib/transport/connectivity_state.c \
-    src/core/lib/transport/mdstr_hash_table.c \
+    src/core/lib/transport/error_utils.c \
     src/core/lib/transport/metadata.c \
     src/core/lib/transport/metadata_batch.c \
     src/core/lib/transport/pid_controller.c \
     src/core/lib/transport/service_config.c \
     src/core/lib/transport/static_metadata.c \
+    src/core/lib/transport/status_conversion.c \
     src/core/lib/transport/timeout_encoding.c \
     src/core/lib/transport/transport.c \
     src/core/lib/transport/transport_op_string.c \
@@ -3079,7 +3054,6 @@ LIBGRPC_CRONET_SRC = \
     src/core/ext/transport/chttp2/transport/huffsyms.c \
     src/core/ext/transport/chttp2/transport/incoming_metadata.c \
     src/core/ext/transport/chttp2/transport/parsing.c \
-    src/core/ext/transport/chttp2/transport/status_conversion.c \
     src/core/ext/transport/chttp2/transport/stream_lists.c \
     src/core/ext/transport/chttp2/transport/stream_map.c \
     src/core/ext/transport/chttp2/transport/varint.c \
@@ -3322,6 +3296,8 @@ LIBGRPC_TEST_UTIL_SRC = \
     src/core/lib/slice/percent_encoding.c \
     src/core/lib/slice/slice.c \
     src/core/lib/slice/slice_buffer.c \
+    src/core/lib/slice/slice_hash_table.c \
+    src/core/lib/slice/slice_intern.c \
     src/core/lib/slice/slice_string_helpers.c \
     src/core/lib/surface/alarm.c \
     src/core/lib/surface/api_trace.c \
@@ -3343,12 +3319,13 @@ LIBGRPC_TEST_UTIL_SRC = \
     src/core/lib/surface/version.c \
     src/core/lib/transport/byte_stream.c \
     src/core/lib/transport/connectivity_state.c \
-    src/core/lib/transport/mdstr_hash_table.c \
+    src/core/lib/transport/error_utils.c \
     src/core/lib/transport/metadata.c \
     src/core/lib/transport/metadata_batch.c \
     src/core/lib/transport/pid_controller.c \
     src/core/lib/transport/service_config.c \
     src/core/lib/transport/static_metadata.c \
+    src/core/lib/transport/status_conversion.c \
     src/core/lib/transport/timeout_encoding.c \
     src/core/lib/transport/transport.c \
     src/core/lib/transport/transport_op_string.c \
@@ -3543,6 +3520,8 @@ LIBGRPC_UNSECURE_SRC = \
     src/core/lib/slice/percent_encoding.c \
     src/core/lib/slice/slice.c \
     src/core/lib/slice/slice_buffer.c \
+    src/core/lib/slice/slice_hash_table.c \
+    src/core/lib/slice/slice_intern.c \
     src/core/lib/slice/slice_string_helpers.c \
     src/core/lib/surface/alarm.c \
     src/core/lib/surface/api_trace.c \
@@ -3564,12 +3543,13 @@ LIBGRPC_UNSECURE_SRC = \
     src/core/lib/surface/version.c \
     src/core/lib/transport/byte_stream.c \
     src/core/lib/transport/connectivity_state.c \
-    src/core/lib/transport/mdstr_hash_table.c \
+    src/core/lib/transport/error_utils.c \
     src/core/lib/transport/metadata.c \
     src/core/lib/transport/metadata_batch.c \
     src/core/lib/transport/pid_controller.c \
     src/core/lib/transport/service_config.c \
     src/core/lib/transport/static_metadata.c \
+    src/core/lib/transport/status_conversion.c \
     src/core/lib/transport/timeout_encoding.c \
     src/core/lib/transport/transport.c \
     src/core/lib/transport/transport_op_string.c \
@@ -3591,7 +3571,6 @@ LIBGRPC_UNSECURE_SRC = \
     src/core/ext/transport/chttp2/transport/huffsyms.c \
     src/core/ext/transport/chttp2/transport/incoming_metadata.c \
     src/core/ext/transport/chttp2/transport/parsing.c \
-    src/core/ext/transport/chttp2/transport/status_conversion.c \
     src/core/ext/transport/chttp2/transport/stream_lists.c \
     src/core/ext/transport/chttp2/transport/stream_map.c \
     src/core/ext/transport/chttp2/transport/varint.c \
@@ -3896,6 +3875,7 @@ PUBLIC_HEADERS_CXX += \
     include/grpc++/impl/codegen/server_context.h \
     include/grpc++/impl/codegen/server_interface.h \
     include/grpc++/impl/codegen/service_type.h \
+    include/grpc++/impl/codegen/slice.h \
     include/grpc++/impl/codegen/status.h \
     include/grpc++/impl/codegen/status_code_enum.h \
     include/grpc++/impl/codegen/status_helper.h \
@@ -4039,7 +4019,6 @@ LIBGRPC++_CRONET_SRC = \
     src/core/ext/transport/chttp2/transport/huffsyms.c \
     src/core/ext/transport/chttp2/transport/incoming_metadata.c \
     src/core/ext/transport/chttp2/transport/parsing.c \
-    src/core/ext/transport/chttp2/transport/status_conversion.c \
     src/core/ext/transport/chttp2/transport/stream_lists.c \
     src/core/ext/transport/chttp2/transport/stream_map.c \
     src/core/ext/transport/chttp2/transport/varint.c \
@@ -4128,6 +4107,8 @@ LIBGRPC++_CRONET_SRC = \
     src/core/lib/slice/percent_encoding.c \
     src/core/lib/slice/slice.c \
     src/core/lib/slice/slice_buffer.c \
+    src/core/lib/slice/slice_hash_table.c \
+    src/core/lib/slice/slice_intern.c \
     src/core/lib/slice/slice_string_helpers.c \
     src/core/lib/surface/alarm.c \
     src/core/lib/surface/api_trace.c \
@@ -4149,12 +4130,13 @@ LIBGRPC++_CRONET_SRC = \
     src/core/lib/surface/version.c \
     src/core/lib/transport/byte_stream.c \
     src/core/lib/transport/connectivity_state.c \
-    src/core/lib/transport/mdstr_hash_table.c \
+    src/core/lib/transport/error_utils.c \
     src/core/lib/transport/metadata.c \
     src/core/lib/transport/metadata_batch.c \
     src/core/lib/transport/pid_controller.c \
     src/core/lib/transport/service_config.c \
     src/core/lib/transport/static_metadata.c \
+    src/core/lib/transport/status_conversion.c \
     src/core/lib/transport/timeout_encoding.c \
     src/core/lib/transport/transport.c \
     src/core/lib/transport/transport_op_string.c \
@@ -4262,6 +4244,7 @@ PUBLIC_HEADERS_CXX += \
     include/grpc++/impl/codegen/server_context.h \
     include/grpc++/impl/codegen/server_interface.h \
     include/grpc++/impl/codegen/service_type.h \
+    include/grpc++/impl/codegen/slice.h \
     include/grpc++/impl/codegen/status.h \
     include/grpc++/impl/codegen/status_code_enum.h \
     include/grpc++/impl/codegen/status_helper.h \
@@ -4619,6 +4602,7 @@ PUBLIC_HEADERS_CXX += \
     include/grpc++/impl/codegen/server_context.h \
     include/grpc++/impl/codegen/server_interface.h \
     include/grpc++/impl/codegen/service_type.h \
+    include/grpc++/impl/codegen/slice.h \
     include/grpc++/impl/codegen/status.h \
     include/grpc++/impl/codegen/status_code_enum.h \
     include/grpc++/impl/codegen/status_helper.h \
@@ -4799,6 +4783,7 @@ PUBLIC_HEADERS_CXX += \
     include/grpc++/impl/codegen/server_context.h \
     include/grpc++/impl/codegen/server_interface.h \
     include/grpc++/impl/codegen/service_type.h \
+    include/grpc++/impl/codegen/slice.h \
     include/grpc++/impl/codegen/status.h \
     include/grpc++/impl/codegen/status_code_enum.h \
     include/grpc++/impl/codegen/status_helper.h \
@@ -7843,38 +7828,6 @@ endif
 endif
 
 
-CHTTP2_STATUS_CONVERSION_TEST_SRC = \
-    test/core/transport/chttp2/status_conversion_test.c \
-
-CHTTP2_STATUS_CONVERSION_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(CHTTP2_STATUS_CONVERSION_TEST_SRC))))
-ifeq ($(NO_SECURE),true)
-
-# You can't build secure targets if you don't have OpenSSL.
-
-$(BINDIR)/$(CONFIG)/chttp2_status_conversion_test: openssl_dep_error
-
-else
-
-
-
-$(BINDIR)/$(CONFIG)/chttp2_status_conversion_test: $(CHTTP2_STATUS_CONVERSION_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
-	$(E) "[LD]      Linking $@"
-	$(Q) mkdir -p `dirname $@`
-	$(Q) $(LD) $(LDFLAGS) $(CHTTP2_STATUS_CONVERSION_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LDLIBS) $(LDLIBS_SECURE) -o $(BINDIR)/$(CONFIG)/chttp2_status_conversion_test
-
-endif
-
-$(OBJDIR)/$(CONFIG)/test/core/transport/chttp2/status_conversion_test.o:  $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
-
-deps_chttp2_status_conversion_test: $(CHTTP2_STATUS_CONVERSION_TEST_OBJS:.o=.dep)
-
-ifneq ($(NO_SECURE),true)
-ifneq ($(NO_DEPS),true)
--include $(CHTTP2_STATUS_CONVERSION_TEST_OBJS:.o=.dep)
-endif
-endif
-
-
 CHTTP2_STREAM_MAP_TEST_SRC = \
     test/core/transport/chttp2/stream_map_test.c \
 
@@ -11299,6 +11252,38 @@ endif
 endif
 
 
+STATUS_CONVERSION_TEST_SRC = \
+    test/core/transport/status_conversion_test.c \
+
+STATUS_CONVERSION_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(STATUS_CONVERSION_TEST_SRC))))
+ifeq ($(NO_SECURE),true)
+
+# You can't build secure targets if you don't have OpenSSL.
+
+$(BINDIR)/$(CONFIG)/status_conversion_test: openssl_dep_error
+
+else
+
+
+
+$(BINDIR)/$(CONFIG)/status_conversion_test: $(STATUS_CONVERSION_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+	$(E) "[LD]      Linking $@"
+	$(Q) mkdir -p `dirname $@`
+	$(Q) $(LD) $(LDFLAGS) $(STATUS_CONVERSION_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LDLIBS) $(LDLIBS_SECURE) -o $(BINDIR)/$(CONFIG)/status_conversion_test
+
+endif
+
+$(OBJDIR)/$(CONFIG)/test/core/transport/status_conversion_test.o:  $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+
+deps_status_conversion_test: $(STATUS_CONVERSION_TEST_OBJS:.o=.dep)
+
+ifneq ($(NO_SECURE),true)
+ifneq ($(NO_DEPS),true)
+-include $(STATUS_CONVERSION_TEST_OBJS:.o=.dep)
+endif
+endif
+
+
 TCP_CLIENT_POSIX_TEST_SRC = \
     test/core/iomgr/tcp_client_posix_test.c \
 
@@ -14194,10 +14179,10 @@ STRESS_TEST_SRC = \
     $(GENDIR)/src/proto/grpc/testing/messages.pb.cc $(GENDIR)/src/proto/grpc/testing/messages.grpc.pb.cc \
     $(GENDIR)/src/proto/grpc/testing/metrics.pb.cc $(GENDIR)/src/proto/grpc/testing/metrics.grpc.pb.cc \
     $(GENDIR)/src/proto/grpc/testing/test.pb.cc $(GENDIR)/src/proto/grpc/testing/test.grpc.pb.cc \
-    test/cpp/interop/client_helper.cc \
     test/cpp/interop/interop_client.cc \
     test/cpp/interop/stress_interop_client.cc \
     test/cpp/interop/stress_test.cc \
+    test/cpp/util/create_test_channel.cc \
     test/cpp/util/metrics_server.cc \
 
 STRESS_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(STRESS_TEST_SRC))))
@@ -14237,14 +14222,14 @@ $(OBJDIR)/$(CONFIG)/src/proto/grpc/testing/metrics.o:  $(LIBDIR)/$(CONFIG)/libgr
 
 $(OBJDIR)/$(CONFIG)/src/proto/grpc/testing/test.o:  $(LIBDIR)/$(CONFIG)/libgrpc++_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LIBDIR)/$(CONFIG)/libgrpc++_test_config.a
 
-$(OBJDIR)/$(CONFIG)/test/cpp/interop/client_helper.o:  $(LIBDIR)/$(CONFIG)/libgrpc++_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LIBDIR)/$(CONFIG)/libgrpc++_test_config.a
-
 $(OBJDIR)/$(CONFIG)/test/cpp/interop/interop_client.o:  $(LIBDIR)/$(CONFIG)/libgrpc++_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LIBDIR)/$(CONFIG)/libgrpc++_test_config.a
 
 $(OBJDIR)/$(CONFIG)/test/cpp/interop/stress_interop_client.o:  $(LIBDIR)/$(CONFIG)/libgrpc++_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LIBDIR)/$(CONFIG)/libgrpc++_test_config.a
 
 $(OBJDIR)/$(CONFIG)/test/cpp/interop/stress_test.o:  $(LIBDIR)/$(CONFIG)/libgrpc++_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LIBDIR)/$(CONFIG)/libgrpc++_test_config.a
 
+$(OBJDIR)/$(CONFIG)/test/cpp/util/create_test_channel.o:  $(LIBDIR)/$(CONFIG)/libgrpc++_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LIBDIR)/$(CONFIG)/libgrpc++_test_config.a
+
 $(OBJDIR)/$(CONFIG)/test/cpp/util/metrics_server.o:  $(LIBDIR)/$(CONFIG)/libgrpc++_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LIBDIR)/$(CONFIG)/libgrpc++_test_config.a
 
 deps_stress_test: $(STRESS_TEST_OBJS:.o=.dep)
@@ -14254,10 +14239,10 @@ ifneq ($(NO_DEPS),true)
 -include $(STRESS_TEST_OBJS:.o=.dep)
 endif
 endif
-$(OBJDIR)/$(CONFIG)/test/cpp/interop/client_helper.o: $(GENDIR)/src/proto/grpc/testing/empty.pb.cc $(GENDIR)/src/proto/grpc/testing/empty.grpc.pb.cc $(GENDIR)/src/proto/grpc/testing/messages.pb.cc $(GENDIR)/src/proto/grpc/testing/messages.grpc.pb.cc $(GENDIR)/src/proto/grpc/testing/metrics.pb.cc $(GENDIR)/src/proto/grpc/testing/metrics.grpc.pb.cc $(GENDIR)/src/proto/grpc/testing/test.pb.cc $(GENDIR)/src/proto/grpc/testing/test.grpc.pb.cc
 $(OBJDIR)/$(CONFIG)/test/cpp/interop/interop_client.o: $(GENDIR)/src/proto/grpc/testing/empty.pb.cc $(GENDIR)/src/proto/grpc/testing/empty.grpc.pb.cc $(GENDIR)/src/proto/grpc/testing/messages.pb.cc $(GENDIR)/src/proto/grpc/testing/messages.grpc.pb.cc $(GENDIR)/src/proto/grpc/testing/metrics.pb.cc $(GENDIR)/src/proto/grpc/testing/metrics.grpc.pb.cc $(GENDIR)/src/proto/grpc/testing/test.pb.cc $(GENDIR)/src/proto/grpc/testing/test.grpc.pb.cc
 $(OBJDIR)/$(CONFIG)/test/cpp/interop/stress_interop_client.o: $(GENDIR)/src/proto/grpc/testing/empty.pb.cc $(GENDIR)/src/proto/grpc/testing/empty.grpc.pb.cc $(GENDIR)/src/proto/grpc/testing/messages.pb.cc $(GENDIR)/src/proto/grpc/testing/messages.grpc.pb.cc $(GENDIR)/src/proto/grpc/testing/metrics.pb.cc $(GENDIR)/src/proto/grpc/testing/metrics.grpc.pb.cc $(GENDIR)/src/proto/grpc/testing/test.pb.cc $(GENDIR)/src/proto/grpc/testing/test.grpc.pb.cc
 $(OBJDIR)/$(CONFIG)/test/cpp/interop/stress_test.o: $(GENDIR)/src/proto/grpc/testing/empty.pb.cc $(GENDIR)/src/proto/grpc/testing/empty.grpc.pb.cc $(GENDIR)/src/proto/grpc/testing/messages.pb.cc $(GENDIR)/src/proto/grpc/testing/messages.grpc.pb.cc $(GENDIR)/src/proto/grpc/testing/metrics.pb.cc $(GENDIR)/src/proto/grpc/testing/metrics.grpc.pb.cc $(GENDIR)/src/proto/grpc/testing/test.pb.cc $(GENDIR)/src/proto/grpc/testing/test.grpc.pb.cc
+$(OBJDIR)/$(CONFIG)/test/cpp/util/create_test_channel.o: $(GENDIR)/src/proto/grpc/testing/empty.pb.cc $(GENDIR)/src/proto/grpc/testing/empty.grpc.pb.cc $(GENDIR)/src/proto/grpc/testing/messages.pb.cc $(GENDIR)/src/proto/grpc/testing/messages.grpc.pb.cc $(GENDIR)/src/proto/grpc/testing/metrics.pb.cc $(GENDIR)/src/proto/grpc/testing/metrics.grpc.pb.cc $(GENDIR)/src/proto/grpc/testing/test.pb.cc $(GENDIR)/src/proto/grpc/testing/test.grpc.pb.cc
 $(OBJDIR)/$(CONFIG)/test/cpp/util/metrics_server.o: $(GENDIR)/src/proto/grpc/testing/empty.pb.cc $(GENDIR)/src/proto/grpc/testing/empty.grpc.pb.cc $(GENDIR)/src/proto/grpc/testing/messages.pb.cc $(GENDIR)/src/proto/grpc/testing/messages.grpc.pb.cc $(GENDIR)/src/proto/grpc/testing/metrics.pb.cc $(GENDIR)/src/proto/grpc/testing/metrics.grpc.pb.cc $(GENDIR)/src/proto/grpc/testing/test.pb.cc $(GENDIR)/src/proto/grpc/testing/test.grpc.pb.cc
 
 

binding.gyp

@@ -679,6 +679,8 @@
         'src/core/lib/slice/percent_encoding.c',
         'src/core/lib/slice/slice.c',
         'src/core/lib/slice/slice_buffer.c',
+        'src/core/lib/slice/slice_hash_table.c',
+        'src/core/lib/slice/slice_intern.c',
         'src/core/lib/slice/slice_string_helpers.c',
         'src/core/lib/surface/alarm.c',
         'src/core/lib/surface/api_trace.c',
@@ -700,12 +702,13 @@
         'src/core/lib/surface/version.c',
         'src/core/lib/transport/byte_stream.c',
         'src/core/lib/transport/connectivity_state.c',
-        'src/core/lib/transport/mdstr_hash_table.c',
+        'src/core/lib/transport/error_utils.c',
         'src/core/lib/transport/metadata.c',
         'src/core/lib/transport/metadata_batch.c',
         'src/core/lib/transport/pid_controller.c',
         'src/core/lib/transport/service_config.c',
         'src/core/lib/transport/static_metadata.c',
+        'src/core/lib/transport/status_conversion.c',
         'src/core/lib/transport/timeout_encoding.c',
         'src/core/lib/transport/transport.c',
         'src/core/lib/transport/transport_op_string.c',
@@ -726,7 +729,6 @@
         'src/core/ext/transport/chttp2/transport/huffsyms.c',
         'src/core/ext/transport/chttp2/transport/incoming_metadata.c',
         'src/core/ext/transport/chttp2/transport/parsing.c',
-        'src/core/ext/transport/chttp2/transport/status_conversion.c',
         'src/core/ext/transport/chttp2/transport/stream_lists.c',
         'src/core/ext/transport/chttp2/transport/stream_map.c',
         'src/core/ext/transport/chttp2/transport/varint.c',
@@ -874,6 +876,7 @@
         "src/node/ext/node_grpc.cc",
         "src/node/ext/server.cc",
         "src/node/ext/server_credentials.cc",
+        "src/node/ext/slice.cc",
         "src/node/ext/timeval.cc",
       ],
       "dependencies": [

build.yaml

@@ -188,6 +188,7 @@ filegroups:
   - src/core/lib/iomgr/endpoint.h
   - src/core/lib/iomgr/endpoint_pair.h
   - src/core/lib/iomgr/error.h
+  - src/core/lib/iomgr/error_internal.h
   - src/core/lib/iomgr/ev_epoll_linux.h
   - src/core/lib/iomgr/ev_poll_posix.h
   - src/core/lib/iomgr/ev_posix.h
@@ -240,6 +241,7 @@ filegroups:
   - src/core/lib/json/json_reader.h
   - src/core/lib/json/json_writer.h
   - src/core/lib/slice/percent_encoding.h
+  - src/core/lib/slice/slice_hash_table.h
   - src/core/lib/slice/slice_internal.h
   - src/core/lib/slice/slice_string_helpers.h
   - src/core/lib/surface/api_trace.h
@@ -253,14 +255,17 @@ filegroups:
   - src/core/lib/surface/init.h
   - src/core/lib/surface/lame_client.h
   - src/core/lib/surface/server.h
+  - src/core/lib/surface/validate_metadata.h
   - src/core/lib/transport/byte_stream.h
   - src/core/lib/transport/connectivity_state.h
-  - src/core/lib/transport/mdstr_hash_table.h
+  - src/core/lib/transport/error_utils.h
+  - src/core/lib/transport/http2_errors.h
   - src/core/lib/transport/metadata.h
   - src/core/lib/transport/metadata_batch.h
   - src/core/lib/transport/pid_controller.h
   - src/core/lib/transport/service_config.h
   - src/core/lib/transport/static_metadata.h
+  - src/core/lib/transport/status_conversion.h
   - src/core/lib/transport/timeout_encoding.h
   - src/core/lib/transport/transport.h
   - src/core/lib/transport/transport_impl.h
@@ -349,6 +354,8 @@ filegroups:
   - src/core/lib/slice/percent_encoding.c
   - src/core/lib/slice/slice.c
   - src/core/lib/slice/slice_buffer.c
+  - src/core/lib/slice/slice_hash_table.c
+  - src/core/lib/slice/slice_intern.c
   - src/core/lib/slice/slice_string_helpers.c
   - src/core/lib/surface/alarm.c
   - src/core/lib/surface/api_trace.c
@@ -370,12 +377,13 @@ filegroups:
   - src/core/lib/surface/version.c
   - src/core/lib/transport/byte_stream.c
   - src/core/lib/transport/connectivity_state.c
-  - src/core/lib/transport/mdstr_hash_table.c
+  - src/core/lib/transport/error_utils.c
   - src/core/lib/transport/metadata.c
   - src/core/lib/transport/metadata_batch.c
   - src/core/lib/transport/pid_controller.c
   - src/core/lib/transport/service_config.c
   - src/core/lib/transport/static_metadata.c
+  - src/core/lib/transport/status_conversion.c
   - src/core/lib/transport/timeout_encoding.c
   - src/core/lib/transport/transport.c
   - src/core/lib/transport/transport_op_string.c
@@ -588,11 +596,9 @@ filegroups:
   - src/core/ext/transport/chttp2/transport/hpack_encoder.h
   - src/core/ext/transport/chttp2/transport/hpack_parser.h
   - src/core/ext/transport/chttp2/transport/hpack_table.h
-  - src/core/ext/transport/chttp2/transport/http2_errors.h
   - src/core/ext/transport/chttp2/transport/huffsyms.h
   - src/core/ext/transport/chttp2/transport/incoming_metadata.h
   - src/core/ext/transport/chttp2/transport/internal.h
-  - src/core/ext/transport/chttp2/transport/status_conversion.h
   - src/core/ext/transport/chttp2/transport/stream_map.h
   - src/core/ext/transport/chttp2/transport/varint.h
   src:
@@ -612,7 +618,6 @@ filegroups:
   - src/core/ext/transport/chttp2/transport/huffsyms.c
   - src/core/ext/transport/chttp2/transport/incoming_metadata.c
   - src/core/ext/transport/chttp2/transport/parsing.c
-  - src/core/ext/transport/chttp2/transport/status_conversion.c
   - src/core/ext/transport/chttp2/transport/stream_lists.c
   - src/core/ext/transport/chttp2/transport/stream_map.c
   - src/core/ext/transport/chttp2/transport/varint.c
@@ -822,6 +827,7 @@ filegroups:
   - include/grpc++/impl/codegen/server_context.h
   - include/grpc++/impl/codegen/server_interface.h
   - include/grpc++/impl/codegen/service_type.h
+  - include/grpc++/impl/codegen/slice.h
   - include/grpc++/impl/codegen/status.h
   - include/grpc++/impl/codegen/status_code_enum.h
   - include/grpc++/impl/codegen/status_helper.h
@@ -1493,16 +1499,6 @@ targets:
   - grpc
   - gpr_test_util
   - gpr
-- name: chttp2_status_conversion_test
-  build: test
-  language: c
-  src:
-  - test/core/transport/chttp2/status_conversion_test.c
-  deps:
-  - grpc_test_util
-  - grpc
-  - gpr_test_util
-  - gpr
 - name: chttp2_stream_map_test
   build: test
   language: c
@@ -2671,6 +2667,16 @@ targets:
   corpus_dirs:
   - test/core/security/corpus/ssl_server_corpus
   maxlen: 2048
+- name: status_conversion_test
+  build: test
+  language: c
+  src:
+  - test/core/transport/status_conversion_test.c
+  deps:
+  - grpc_test_util
+  - grpc
+  - gpr_test_util
+  - gpr
 - name: tcp_client_posix_test
   cpu_cost: 0.5
   build: test
@@ -3646,16 +3652,17 @@ targets:
   - test/cpp/interop/client_helper.h
   - test/cpp/interop/interop_client.h
   - test/cpp/interop/stress_interop_client.h
+  - test/cpp/util/create_test_channel.h
   - test/cpp/util/metrics_server.h
   src:
   - src/proto/grpc/testing/empty.proto
   - src/proto/grpc/testing/messages.proto
   - src/proto/grpc/testing/metrics.proto
   - src/proto/grpc/testing/test.proto
-  - test/cpp/interop/client_helper.cc
   - test/cpp/interop/interop_client.cc
   - test/cpp/interop/stress_interop_client.cc
   - test/cpp/interop/stress_test.cc
+  - test/cpp/util/create_test_channel.cc
   - test/cpp/util/metrics_server.cc
   deps:
   - grpc++_test_util
@@ -3761,36 +3768,6 @@ configs:
   dbg:
     CPPFLAGS: -O0
     DEFINES: _DEBUG DEBUG
-  easan:
-    CC: clang
-    CPPFLAGS: -O0 -fsanitize-coverage=edge -fsanitize=address -fno-omit-frame-pointer
-      -Wno-unused-command-line-argument -DGPR_NO_DIRECT_SYSCALLS
-    CXX: clang++
-    DEFINES: _DEBUG DEBUG GRPC_EXECUTION_CONTEXT_SANITIZER
-    LD: clang
-    LDFLAGS: -fsanitize=address
-    LDXX: clang++
-    compile_the_world: true
-    test_environ:
-      ASAN_OPTIONS: detect_leaks=1:color=always
-      LSAN_OPTIONS: suppressions=tools/lsan_suppressions.txt:report_objects=1
-    timeout_multiplier: 3
-  edbg:
-    CPPFLAGS: -O0
-    DEFINES: _DEBUG DEBUG GRPC_EXECUTION_CONTEXT_SANITIZER
-  etsan:
-    CC: clang
-    CPPFLAGS: -O0 -fsanitize=thread -fno-omit-frame-pointer -Wno-unused-command-line-argument
-      -DGPR_NO_DIRECT_SYSCALLS
-    CXX: clang++
-    DEFINES: _DEBUG DEBUG GRPC_EXECUTION_CONTEXT_SANITIZER
-    LD: clang
-    LDFLAGS: -fsanitize=thread
-    LDXX: clang++
-    compile_the_world: true
-    test_environ:
-      TSAN_OPTIONS: suppressions=tools/tsan_suppressions.txt:halt_on_error=1:second_deadlock_stack=1
-    timeout_multiplier: 5
   gcov:
     CC: gcc
     CPPFLAGS: -O0 -fprofile-arcs -ftest-coverage -Wno-return-type
@@ -3889,6 +3866,7 @@ node_modules:
   - src/node/ext/completion_queue.h
   - src/node/ext/server.h
   - src/node/ext/server_credentials.h
+  - src/node/ext/slice.h
   - src/node/ext/timeval.h
   js:
   - src/node/index.js
@@ -3910,6 +3888,7 @@ node_modules:
   - src/node/ext/node_grpc.cc
   - src/node/ext/server.cc
   - src/node/ext/server_credentials.cc
+  - src/node/ext/slice.cc
   - src/node/ext/timeval.cc
 openssl_fallback:
   base_uri: https://openssl.org/source/old/1.0.2/

config.m4

@@ -165,6 +165,8 @@ if test "$PHP_GRPC" != "no"; then
     src/core/lib/slice/percent_encoding.c \
     src/core/lib/slice/slice.c \
     src/core/lib/slice/slice_buffer.c \
+    src/core/lib/slice/slice_hash_table.c \
+    src/core/lib/slice/slice_intern.c \
     src/core/lib/slice/slice_string_helpers.c \
     src/core/lib/surface/alarm.c \
     src/core/lib/surface/api_trace.c \
@@ -186,12 +188,13 @@ if test "$PHP_GRPC" != "no"; then
     src/core/lib/surface/version.c \
     src/core/lib/transport/byte_stream.c \
     src/core/lib/transport/connectivity_state.c \
-    src/core/lib/transport/mdstr_hash_table.c \
+    src/core/lib/transport/error_utils.c \
     src/core/lib/transport/metadata.c \
     src/core/lib/transport/metadata_batch.c \
     src/core/lib/transport/pid_controller.c \
     src/core/lib/transport/service_config.c \
     src/core/lib/transport/static_metadata.c \
+    src/core/lib/transport/status_conversion.c \
     src/core/lib/transport/timeout_encoding.c \
     src/core/lib/transport/transport.c \
     src/core/lib/transport/transport_op_string.c \
@@ -212,7 +215,6 @@ if test "$PHP_GRPC" != "no"; then
     src/core/ext/transport/chttp2/transport/huffsyms.c \
     src/core/ext/transport/chttp2/transport/incoming_metadata.c \
     src/core/ext/transport/chttp2/transport/parsing.c \
-    src/core/ext/transport/chttp2/transport/status_conversion.c \
     src/core/ext/transport/chttp2/transport/stream_lists.c \
     src/core/ext/transport/chttp2/transport/stream_map.c \
     src/core/ext/transport/chttp2/transport/varint.c \

doc/PROTOCOL-HTTP2.md

@@ -153,6 +153,7 @@ DATA (flags = END_STREAM)
 HEADERS (flags = END_HEADERS)
 :status = 200
 grpc-encoding = gzip
+content-type = application/grpc+proto
 
 DATA
 <Length-Prefixed Message>

doc/environment_variables.md

@@ -55,10 +55,12 @@ some configuration as environment variables that can be set.
   - secure_endpoint - traces bytes flowing through encrypted channels
   - transport_security - traces metadata about secure channel establishment
   - tcp - traces bytes in and out of a channel
+  
   'all' can additionally be used to turn all traces on.
   Individual traces can be disabled by prefixing them with '-'.
+ 
   Example:
-   export GRPC_TRACE=all,-pending_tags
+  export GRPC_TRACE=all,-pending_tags
 
 * GRPC_VERBOSITY
   Default gRPC logging verbosity - one of:

gRPC-Core.podspec

@@ -274,6 +274,7 @@ Pod::Spec.new do |s|
                       'src/core/lib/iomgr/endpoint.h',
                       'src/core/lib/iomgr/endpoint_pair.h',
                       'src/core/lib/iomgr/error.h',
+                      'src/core/lib/iomgr/error_internal.h',
                       'src/core/lib/iomgr/ev_epoll_linux.h',
                       'src/core/lib/iomgr/ev_poll_posix.h',
                       'src/core/lib/iomgr/ev_posix.h',
@@ -326,6 +327,7 @@ Pod::Spec.new do |s|
                       'src/core/lib/json/json_reader.h',
                       'src/core/lib/json/json_writer.h',
                       'src/core/lib/slice/percent_encoding.h',
+                      'src/core/lib/slice/slice_hash_table.h',
                       'src/core/lib/slice/slice_internal.h',
                       'src/core/lib/slice/slice_string_helpers.h',
                       'src/core/lib/surface/api_trace.h',
@@ -339,14 +341,17 @@ Pod::Spec.new do |s|
                       'src/core/lib/surface/init.h',
                       'src/core/lib/surface/lame_client.h',
                       'src/core/lib/surface/server.h',
+                      'src/core/lib/surface/validate_metadata.h',
                       'src/core/lib/transport/byte_stream.h',
                       'src/core/lib/transport/connectivity_state.h',
-                      'src/core/lib/transport/mdstr_hash_table.h',
+                      'src/core/lib/transport/error_utils.h',
+                      'src/core/lib/transport/http2_errors.h',
                       'src/core/lib/transport/metadata.h',
                       'src/core/lib/transport/metadata_batch.h',
                       'src/core/lib/transport/pid_controller.h',
                       'src/core/lib/transport/service_config.h',
                       'src/core/lib/transport/static_metadata.h',
+                      'src/core/lib/transport/status_conversion.h',
                       'src/core/lib/transport/timeout_encoding.h',
                       'src/core/lib/transport/transport.h',
                       'src/core/lib/transport/transport_impl.h',
@@ -363,11 +368,9 @@ Pod::Spec.new do |s|
                       'src/core/ext/transport/chttp2/transport/hpack_encoder.h',
                       'src/core/ext/transport/chttp2/transport/hpack_parser.h',
                       'src/core/ext/transport/chttp2/transport/hpack_table.h',
-                      'src/core/ext/transport/chttp2/transport/http2_errors.h',
                       'src/core/ext/transport/chttp2/transport/huffsyms.h',
                       'src/core/ext/transport/chttp2/transport/incoming_metadata.h',
                       'src/core/ext/transport/chttp2/transport/internal.h',
-                      'src/core/ext/transport/chttp2/transport/status_conversion.h',
                       'src/core/ext/transport/chttp2/transport/stream_map.h',
                       'src/core/ext/transport/chttp2/transport/varint.h',
                       'src/core/ext/transport/chttp2/alpn/alpn.h',
@@ -517,6 +520,8 @@ Pod::Spec.new do |s|
                       'src/core/lib/slice/percent_encoding.c',
                       'src/core/lib/slice/slice.c',
                       'src/core/lib/slice/slice_buffer.c',
+                      'src/core/lib/slice/slice_hash_table.c',
+                      'src/core/lib/slice/slice_intern.c',
                       'src/core/lib/slice/slice_string_helpers.c',
                       'src/core/lib/surface/alarm.c',
                       'src/core/lib/surface/api_trace.c',
@@ -538,12 +543,13 @@ Pod::Spec.new do |s|
                       'src/core/lib/surface/version.c',
                       'src/core/lib/transport/byte_stream.c',
                       'src/core/lib/transport/connectivity_state.c',
-                      'src/core/lib/transport/mdstr_hash_table.c',
+                      'src/core/lib/transport/error_utils.c',
                       'src/core/lib/transport/metadata.c',
                       'src/core/lib/transport/metadata_batch.c',
                       'src/core/lib/transport/pid_controller.c',
                       'src/core/lib/transport/service_config.c',
                       'src/core/lib/transport/static_metadata.c',
+                      'src/core/lib/transport/status_conversion.c',
                       'src/core/lib/transport/timeout_encoding.c',
                       'src/core/lib/transport/transport.c',
                       'src/core/lib/transport/transport_op_string.c',
@@ -564,7 +570,6 @@ Pod::Spec.new do |s|
                       'src/core/ext/transport/chttp2/transport/huffsyms.c',
                       'src/core/ext/transport/chttp2/transport/incoming_metadata.c',
                       'src/core/ext/transport/chttp2/transport/parsing.c',
-                      'src/core/ext/transport/chttp2/transport/status_conversion.c',
                       'src/core/ext/transport/chttp2/transport/stream_lists.c',
                       'src/core/ext/transport/chttp2/transport/stream_map.c',
                       'src/core/ext/transport/chttp2/transport/varint.c',
@@ -686,6 +691,7 @@ Pod::Spec.new do |s|
                               'src/core/lib/iomgr/endpoint.h',
                               'src/core/lib/iomgr/endpoint_pair.h',
                               'src/core/lib/iomgr/error.h',
+                              'src/core/lib/iomgr/error_internal.h',
                               'src/core/lib/iomgr/ev_epoll_linux.h',
                               'src/core/lib/iomgr/ev_poll_posix.h',
                               'src/core/lib/iomgr/ev_posix.h',
@@ -738,6 +744,7 @@ Pod::Spec.new do |s|
                               'src/core/lib/json/json_reader.h',
                               'src/core/lib/json/json_writer.h',
                               'src/core/lib/slice/percent_encoding.h',
+                              'src/core/lib/slice/slice_hash_table.h',
                               'src/core/lib/slice/slice_internal.h',
                               'src/core/lib/slice/slice_string_helpers.h',
                               'src/core/lib/surface/api_trace.h',
@@ -751,14 +758,17 @@ Pod::Spec.new do |s|
                               'src/core/lib/surface/init.h',
                               'src/core/lib/surface/lame_client.h',
                               'src/core/lib/surface/server.h',
+                              'src/core/lib/surface/validate_metadata.h',
                               'src/core/lib/transport/byte_stream.h',
                               'src/core/lib/transport/connectivity_state.h',
-                              'src/core/lib/transport/mdstr_hash_table.h',
+                              'src/core/lib/transport/error_utils.h',
+                              'src/core/lib/transport/http2_errors.h',
                               'src/core/lib/transport/metadata.h',
                               'src/core/lib/transport/metadata_batch.h',
                               'src/core/lib/transport/pid_controller.h',
                               'src/core/lib/transport/service_config.h',
                               'src/core/lib/transport/static_metadata.h',
+                              'src/core/lib/transport/status_conversion.h',
                               'src/core/lib/transport/timeout_encoding.h',
                               'src/core/lib/transport/transport.h',
                               'src/core/lib/transport/transport_impl.h',
@@ -775,11 +785,9 @@ Pod::Spec.new do |s|
                               'src/core/ext/transport/chttp2/transport/hpack_encoder.h',
                               'src/core/ext/transport/chttp2/transport/hpack_parser.h',
                               'src/core/ext/transport/chttp2/transport/hpack_table.h',
-                              'src/core/ext/transport/chttp2/transport/http2_errors.h',
                               'src/core/ext/transport/chttp2/transport/huffsyms.h',
                               'src/core/ext/transport/chttp2/transport/incoming_metadata.h',
                               'src/core/ext/transport/chttp2/transport/internal.h',
-                              'src/core/ext/transport/chttp2/transport/status_conversion.h',
                               'src/core/ext/transport/chttp2/transport/stream_map.h',
                               'src/core/ext/transport/chttp2/transport/varint.h',
                               'src/core/ext/transport/chttp2/alpn/alpn.h',

grpc.def

@@ -141,17 +141,30 @@ EXPORTS
     grpc_slice_new_with_user_data
     grpc_slice_new_with_len
     grpc_slice_malloc
+    grpc_slice_intern
     grpc_slice_from_copied_string
     grpc_slice_from_copied_buffer
     grpc_slice_from_static_string
+    grpc_slice_from_static_buffer
     grpc_slice_sub
     grpc_slice_sub_no_ref
     grpc_slice_split_tail
     grpc_slice_split_head
-    gpr_empty_slice
+    grpc_empty_slice
+    grpc_slice_default_hash_impl
+    grpc_slice_default_eq_impl
+    grpc_slice_eq
     grpc_slice_cmp
     grpc_slice_str_cmp
+    grpc_slice_buf_cmp
+    grpc_slice_buf_start_eq
+    grpc_slice_rchr
+    grpc_slice_chr
+    grpc_slice_slice
+    grpc_slice_hash
     grpc_slice_is_equivalent
+    grpc_slice_dup
+    grpc_slice_to_c_string
     grpc_slice_buffer_init
     grpc_slice_buffer_destroy
     grpc_slice_buffer_add

grpc.gemspec

@@ -191,6 +191,7 @@ Gem::Specification.new do |s|
   s.files += %w( src/core/lib/iomgr/endpoint.h )
   s.files += %w( src/core/lib/iomgr/endpoint_pair.h )
   s.files += %w( src/core/lib/iomgr/error.h )
+  s.files += %w( src/core/lib/iomgr/error_internal.h )
   s.files += %w( src/core/lib/iomgr/ev_epoll_linux.h )
   s.files += %w( src/core/lib/iomgr/ev_poll_posix.h )
   s.files += %w( src/core/lib/iomgr/ev_posix.h )
@@ -243,6 +244,7 @@ Gem::Specification.new do |s|
   s.files += %w( src/core/lib/json/json_reader.h )
   s.files += %w( src/core/lib/json/json_writer.h )
   s.files += %w( src/core/lib/slice/percent_encoding.h )
+  s.files += %w( src/core/lib/slice/slice_hash_table.h )
   s.files += %w( src/core/lib/slice/slice_internal.h )
   s.files += %w( src/core/lib/slice/slice_string_helpers.h )
   s.files += %w( src/core/lib/surface/api_trace.h )
@@ -256,14 +258,17 @@ Gem::Specification.new do |s|
   s.files += %w( src/core/lib/surface/init.h )
   s.files += %w( src/core/lib/surface/lame_client.h )
   s.files += %w( src/core/lib/surface/server.h )
+  s.files += %w( src/core/lib/surface/validate_metadata.h )
   s.files += %w( src/core/lib/transport/byte_stream.h )
   s.files += %w( src/core/lib/transport/connectivity_state.h )
-  s.files += %w( src/core/lib/transport/mdstr_hash_table.h )
+  s.files += %w( src/core/lib/transport/error_utils.h )
+  s.files += %w( src/core/lib/transport/http2_errors.h )
   s.files += %w( src/core/lib/transport/metadata.h )
   s.files += %w( src/core/lib/transport/metadata_batch.h )
   s.files += %w( src/core/lib/transport/pid_controller.h )
   s.files += %w( src/core/lib/transport/service_config.h )
   s.files += %w( src/core/lib/transport/static_metadata.h )
+  s.files += %w( src/core/lib/transport/status_conversion.h )
   s.files += %w( src/core/lib/transport/timeout_encoding.h )
   s.files += %w( src/core/lib/transport/transport.h )
   s.files += %w( src/core/lib/transport/transport_impl.h )
@@ -280,11 +285,9 @@ Gem::Specification.new do |s|
   s.files += %w( src/core/ext/transport/chttp2/transport/hpack_encoder.h )
   s.files += %w( src/core/ext/transport/chttp2/transport/hpack_parser.h )
   s.files += %w( src/core/ext/transport/chttp2/transport/hpack_table.h )
-  s.files += %w( src/core/ext/transport/chttp2/transport/http2_errors.h )
   s.files += %w( src/core/ext/transport/chttp2/transport/huffsyms.h )
   s.files += %w( src/core/ext/transport/chttp2/transport/incoming_metadata.h )
   s.files += %w( src/core/ext/transport/chttp2/transport/internal.h )
-  s.files += %w( src/core/ext/transport/chttp2/transport/status_conversion.h )
   s.files += %w( src/core/ext/transport/chttp2/transport/stream_map.h )
   s.files += %w( src/core/ext/transport/chttp2/transport/varint.h )
   s.files += %w( src/core/ext/transport/chttp2/alpn/alpn.h )
@@ -434,6 +437,8 @@ Gem::Specification.new do |s|
   s.files += %w( src/core/lib/slice/percent_encoding.c )
   s.files += %w( src/core/lib/slice/slice.c )
   s.files += %w( src/core/lib/slice/slice_buffer.c )
+  s.files += %w( src/core/lib/slice/slice_hash_table.c )
+  s.files += %w( src/core/lib/slice/slice_intern.c )
   s.files += %w( src/core/lib/slice/slice_string_helpers.c )
   s.files += %w( src/core/lib/surface/alarm.c )
   s.files += %w( src/core/lib/surface/api_trace.c )
@@ -455,12 +460,13 @@ Gem::Specification.new do |s|
   s.files += %w( src/core/lib/surface/version.c )
   s.files += %w( src/core/lib/transport/byte_stream.c )
   s.files += %w( src/core/lib/transport/connectivity_state.c )
-  s.files += %w( src/core/lib/transport/mdstr_hash_table.c )
+  s.files += %w( src/core/lib/transport/error_utils.c )
   s.files += %w( src/core/lib/transport/metadata.c )
   s.files += %w( src/core/lib/transport/metadata_batch.c )
   s.files += %w( src/core/lib/transport/pid_controller.c )
   s.files += %w( src/core/lib/transport/service_config.c )
   s.files += %w( src/core/lib/transport/static_metadata.c )
+  s.files += %w( src/core/lib/transport/status_conversion.c )
   s.files += %w( src/core/lib/transport/timeout_encoding.c )
   s.files += %w( src/core/lib/transport/transport.c )
   s.files += %w( src/core/lib/transport/transport_op_string.c )
@@ -481,7 +487,6 @@ Gem::Specification.new do |s|
   s.files += %w( src/core/ext/transport/chttp2/transport/huffsyms.c )
   s.files += %w( src/core/ext/transport/chttp2/transport/incoming_metadata.c )
   s.files += %w( src/core/ext/transport/chttp2/transport/parsing.c )
-  s.files += %w( src/core/ext/transport/chttp2/transport/status_conversion.c )
   s.files += %w( src/core/ext/transport/chttp2/transport/stream_lists.c )
   s.files += %w( src/core/ext/transport/chttp2/transport/stream_map.c )
   s.files += %w( src/core/ext/transport/chttp2/transport/varint.c )

include/grpc++/impl/codegen/call.h

@@ -45,6 +45,7 @@
 #include <grpc++/impl/codegen/config.h>
 #include <grpc++/impl/codegen/core_codegen_interface.h>
 #include <grpc++/impl/codegen/serialization_traits.h>
+#include <grpc++/impl/codegen/slice.h>
 #include <grpc++/impl/codegen/status.h>
 #include <grpc++/impl/codegen/status_helper.h>
 #include <grpc++/impl/codegen/string_ref.h>
@@ -62,19 +63,6 @@ class CallHook;
 class CompletionQueue;
 extern CoreCodegenInterface* g_core_codegen_interface;
 
-inline void FillMetadataMap(
-    grpc_metadata_array* arr,
-    std::multimap<grpc::string_ref, grpc::string_ref>* metadata) {
-  for (size_t i = 0; i < arr->count; i++) {
-    // TODO(yangg) handle duplicates?
-    metadata->insert(std::pair<grpc::string_ref, grpc::string_ref>(
-        arr->metadata[i].key, grpc::string_ref(arr->metadata[i].value,
-                                               arr->metadata[i].value_length)));
-  }
-  g_core_codegen_interface->grpc_metadata_array_destroy(arr);
-  g_core_codegen_interface->grpc_metadata_array_init(arr);
-}
-
 // TODO(yangg) if the map is changed before we send, the pointers will be a
 // mess. Make sure it does not happen.
 inline grpc_metadata* FillMetadataArray(
@@ -87,9 +75,8 @@ inline grpc_metadata* FillMetadataArray(
           metadata.size() * sizeof(grpc_metadata)));
   size_t i = 0;
   for (auto iter = metadata.cbegin(); iter != metadata.cend(); ++iter, ++i) {
-    metadata_array[i].key = iter->first.c_str();
-    metadata_array[i].value = iter->second.c_str();
-    metadata_array[i].value_length = iter->second.size();
+    metadata_array[i].key = SliceReferencingString(iter->first);
+    metadata_array[i].value = SliceReferencingString(iter->second);
   }
   return metadata_array;
 }
@@ -445,8 +432,9 @@ class CallOpServerSendStatus {
         trailing_metadata_count_;
     op->data.send_status_from_server.trailing_metadata = trailing_metadata_;
     op->data.send_status_from_server.status = send_status_code_;
+    status_details_slice_ = SliceReferencingString(send_status_details_);
     op->data.send_status_from_server.status_details =
-        send_status_details_.empty() ? nullptr : send_status_details_.c_str();
+        send_status_details_.empty() ? nullptr : &status_details_slice_;
     op->flags = 0;
     op->reserved = NULL;
   }
@@ -463,36 +451,35 @@ class CallOpServerSendStatus {
   grpc::string send_status_details_;
   size_t trailing_metadata_count_;
   grpc_metadata* trailing_metadata_;
+  grpc_slice status_details_slice_;
 };
 
 class CallOpRecvInitialMetadata {
  public:
-  CallOpRecvInitialMetadata() : recv_initial_metadata_(nullptr) {}
+  CallOpRecvInitialMetadata() : metadata_map_(nullptr) {}
 
   void RecvInitialMetadata(ClientContext* context) {
     context->initial_metadata_received_ = true;
-    recv_initial_metadata_ = &context->recv_initial_metadata_;
+    metadata_map_ = &context->recv_initial_metadata_;
   }
 
  protected:
   void AddOp(grpc_op* ops, size_t* nops) {
-    if (!recv_initial_metadata_) return;
-    memset(&recv_initial_metadata_arr_, 0, sizeof(recv_initial_metadata_arr_));
+    if (metadata_map_ == nullptr) return;
     grpc_op* op = &ops[(*nops)++];
     op->op = GRPC_OP_RECV_INITIAL_METADATA;
-    op->data.recv_initial_metadata = &recv_initial_metadata_arr_;
+    op->data.recv_initial_metadata = metadata_map_->arr();
     op->flags = 0;
     op->reserved = NULL;
   }
   void FinishOp(bool* status) {
-    if (recv_initial_metadata_ == nullptr) return;
-    FillMetadataMap(&recv_initial_metadata_arr_, recv_initial_metadata_);
-    recv_initial_metadata_ = nullptr;
+    if (metadata_map_ == nullptr) return;
+    metadata_map_->FillMap();
+    metadata_map_ = nullptr;
   }
 
  private:
-  std::multimap<grpc::string_ref, grpc::string_ref>* recv_initial_metadata_;
-  grpc_metadata_array recv_initial_metadata_arr_;
+  MetadataMap* metadata_map_;
 };
 
 class CallOpClientRecvStatus {
@@ -500,46 +487,37 @@ class CallOpClientRecvStatus {
   CallOpClientRecvStatus() : recv_status_(nullptr) {}
 
   void ClientRecvStatus(ClientContext* context, Status* status) {
-    recv_trailing_metadata_ = &context->trailing_metadata_;
+    metadata_map_ = &context->trailing_metadata_;
     recv_status_ = status;
   }
 
  protected:
   void AddOp(grpc_op* ops, size_t* nops) {
     if (recv_status_ == nullptr) return;
-    memset(&recv_trailing_metadata_arr_, 0,
-           sizeof(recv_trailing_metadata_arr_));
-    status_details_ = nullptr;
-    status_details_capacity_ = 0;
     grpc_op* op = &ops[(*nops)++];
     op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
-    op->data.recv_status_on_client.trailing_metadata =
-        &recv_trailing_metadata_arr_;
+    op->data.recv_status_on_client.trailing_metadata = metadata_map_->arr();
     op->data.recv_status_on_client.status = &status_code_;
     op->data.recv_status_on_client.status_details = &status_details_;
-    op->data.recv_status_on_client.status_details_capacity =
-        &status_details_capacity_;
     op->flags = 0;
     op->reserved = NULL;
   }
 
   void FinishOp(bool* status) {
     if (recv_status_ == nullptr) return;
-    FillMetadataMap(&recv_trailing_metadata_arr_, recv_trailing_metadata_);
-    *recv_status_ = Status(
-        static_cast<StatusCode>(status_code_),
-        status_details_ ? grpc::string(status_details_) : grpc::string());
-    g_core_codegen_interface->gpr_free(status_details_);
+    metadata_map_->FillMap();
+    *recv_status_ = Status(static_cast<StatusCode>(status_code_),
+                           grpc::string(GRPC_SLICE_START_PTR(status_details_),
+                                        GRPC_SLICE_END_PTR(status_details_)));
+    g_core_codegen_interface->grpc_slice_unref(status_details_);
     recv_status_ = nullptr;
   }
 
  private:
-  std::multimap<grpc::string_ref, grpc::string_ref>* recv_trailing_metadata_;
+  MetadataMap* metadata_map_;
   Status* recv_status_;
-  grpc_metadata_array recv_trailing_metadata_arr_;
   grpc_status_code status_code_;
-  char* status_details_;
-  size_t status_details_capacity_;
+  grpc_slice status_details_;
 };
 
 /// An abstract collection of CallOpSet's, to be used whenever

include/grpc++/impl/codegen/client_context.h

@@ -57,7 +57,9 @@
 #include <grpc++/impl/codegen/config.h>
 #include <grpc++/impl/codegen/core_codegen_interface.h>
 #include <grpc++/impl/codegen/create_auth_context.h>
+#include <grpc++/impl/codegen/metadata_map.h>
 #include <grpc++/impl/codegen/security/auth_context.h>
+#include <grpc++/impl/codegen/slice.h>
 #include <grpc++/impl/codegen/status.h>
 #include <grpc++/impl/codegen/string_ref.h>
 #include <grpc++/impl/codegen/time.h>
@@ -193,7 +195,7 @@ class ClientContext {
   const std::multimap<grpc::string_ref, grpc::string_ref>&
   GetServerInitialMetadata() const {
     GPR_CODEGEN_ASSERT(initial_metadata_received_);
-    return recv_initial_metadata_;
+    return *recv_initial_metadata_.map();
   }
 
   /// Return a collection of trailing metadata key-value pairs. Note that keys
@@ -205,7 +207,7 @@ class ClientContext {
   const std::multimap<grpc::string_ref, grpc::string_ref>&
   GetServerTrailingMetadata() const {
     // TODO(yangg) check finished
-    return trailing_metadata_;
+    return *trailing_metadata_.map();
   }
 
   /// Set the deadline for the client call.
@@ -375,8 +377,8 @@ class ClientContext {
   mutable std::shared_ptr<const AuthContext> auth_context_;
   struct census_context* census_context_;
   std::multimap<grpc::string, grpc::string> send_initial_metadata_;
-  std::multimap<grpc::string_ref, grpc::string_ref> recv_initial_metadata_;
-  std::multimap<grpc::string_ref, grpc::string_ref> trailing_metadata_;
+  MetadataMap recv_initial_metadata_;
+  MetadataMap trailing_metadata_;
 
   grpc_call* propagate_from_call_;
   PropagationOptions propagation_options_;

include/grpc++/impl/codegen/client_unary_call.h

@@ -69,7 +69,14 @@ Status BlockingUnaryCall(ChannelInterface* channel, const RpcMethod& method,
   ops.ClientSendClose();
   ops.ClientRecvStatus(context, &status);
   call.PerformOps(&ops);
-  GPR_CODEGEN_ASSERT((cq.Pluck(&ops) && ops.got_message) || !status.ok());
+  if (cq.Pluck(&ops)) {
+    if (!ops.got_message && status.ok()) {
+      return Status(StatusCode::UNIMPLEMENTED,
+                    "No message returned for unary request");
+    }
+  } else {
+    GPR_CODEGEN_ASSERT(!status.ok());
+  }
   return status;
 }
 

include/grpc++/impl/codegen/config.h

@@ -39,6 +39,12 @@
 #define GRPC_CUSTOM_STRING std::string
 #endif
 
+// The following macros are deprecated and appear only for users
+// with PB files generated using gRPC 1.0.x plugins. They should
+// not be used in new code
+#define GRPC_OVERRIDE override  // deprecated
+#define GRPC_FINAL final        // deprecated
+
 namespace grpc {
 
 typedef GRPC_CUSTOM_STRING string;

include/grpc++/impl/codegen/core_codegen.h

@@ -81,7 +81,10 @@ class CoreCodegen : public CoreCodegenInterface {
   grpc_slice grpc_slice_split_tail(grpc_slice* s, size_t split) override;
   void grpc_slice_buffer_add(grpc_slice_buffer* sb, grpc_slice slice) override;
   void grpc_slice_buffer_pop(grpc_slice_buffer* sb) override;
-
+  grpc_slice grpc_slice_from_static_buffer(const void* buffer,
+                                           size_t length) override;
+  grpc_slice grpc_slice_from_copied_buffer(const void* buffer,
+                                           size_t length) override;
   void grpc_metadata_array_init(grpc_metadata_array* array) override;
   void grpc_metadata_array_destroy(grpc_metadata_array* array) override;
 
@@ -91,7 +94,8 @@ class CoreCodegen : public CoreCodegenInterface {
   virtual const Status& ok() override;
   virtual const Status& cancelled() override;
 
-  void assert_fail(const char* failed_assertion) override;
+  void assert_fail(const char* failed_assertion, const char* file,
+                   int line) override;
 };
 
 }  // namespace grpc

include/grpc++/impl/codegen/core_codegen_interface.h

@@ -56,7 +56,8 @@ namespace grpc {
 class CoreCodegenInterface {
  public:
   /// Upon a failed assertion, log the error.
-  virtual void assert_fail(const char* failed_assertion) = 0;
+  virtual void assert_fail(const char* failed_assertion, const char* file,
+                           int line) = 0;
 
   virtual grpc_completion_queue* grpc_completion_queue_create(
       void* reserved) = 0;
@@ -99,6 +100,10 @@ class CoreCodegenInterface {
   virtual void grpc_slice_buffer_add(grpc_slice_buffer* sb,
                                      grpc_slice slice) = 0;
   virtual void grpc_slice_buffer_pop(grpc_slice_buffer* sb) = 0;
+  virtual grpc_slice grpc_slice_from_static_buffer(const void* buffer,
+                                                   size_t length) = 0;
+  virtual grpc_slice grpc_slice_from_copied_buffer(const void* buffer,
+                                                   size_t length) = 0;
 
   virtual void grpc_metadata_array_init(grpc_metadata_array* array) = 0;
   virtual void grpc_metadata_array_destroy(grpc_metadata_array* array) = 0;
@@ -113,11 +118,11 @@ class CoreCodegenInterface {
 extern CoreCodegenInterface* g_core_codegen_interface;
 
 /// Codegen specific version of \a GPR_ASSERT.
-#define GPR_CODEGEN_ASSERT(x)                          \
-  do {                                                 \
-    if (!(x)) {                                        \
-      grpc::g_core_codegen_interface->assert_fail(#x); \
-    }                                                  \
+#define GPR_CODEGEN_ASSERT(x)                                              \
+  do {                                                                     \
+    if (!(x)) {                                                            \
+      grpc::g_core_codegen_interface->assert_fail(#x, __FILE__, __LINE__); \
+    }                                                                      \
   } while (0)
 
 }  // namespace grpc

include/grpc++/impl/codegen/metadata_map.h

@@ -0,0 +1,71 @@
+/*
+*
+* Copyright 2015, Google Inc.
+* All rights reserved.
+*
+* Redistribution and use in source and binary forms, with or without
+* modification, are permitted provided that the following conditions are
+* met:
+*
+*     * Redistributions of source code must retain the above copyright
+* notice, this list of conditions and the following disclaimer.
+*     * Redistributions in binary form must reproduce the above
+* copyright notice, this list of conditions and the following disclaimer
+* in the documentation and/or other materials provided with the
+* distribution.
+*     * Neither the name of Google Inc. nor the names of its
+* contributors may be used to endorse or promote products derived from
+* this software without specific prior written permission.
+*
+* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*
+*/
+
+#ifndef GRPCXX_IMPL_CODEGEN_METADATA_MAP_H
+#define GRPCXX_IMPL_CODEGEN_METADATA_MAP_H
+
+#include <grpc++/impl/codegen/slice.h>
+
+namespace grpc {
+
+class MetadataMap {
+ public:
+  MetadataMap() { memset(&arr_, 0, sizeof(arr_)); }
+
+  ~MetadataMap() {
+    g_core_codegen_interface->grpc_metadata_array_destroy(&arr_);
+  }
+
+  void FillMap() {
+    for (size_t i = 0; i < arr_.count; i++) {
+      // TODO(yangg) handle duplicates?
+      map_.insert(std::pair<grpc::string_ref, grpc::string_ref>(
+          StringRefFromSlice(&arr_.metadata[i].key),
+          StringRefFromSlice(&arr_.metadata[i].value)));
+    }
+  }
+
+  std::multimap<grpc::string_ref, grpc::string_ref> *map() { return &map_; }
+  const std::multimap<grpc::string_ref, grpc::string_ref> *map() const {
+    return &map_;
+  }
+  grpc_metadata_array *arr() { return &arr_; }
+
+ private:
+  grpc_metadata_array arr_;
+  std::multimap<grpc::string_ref, grpc::string_ref> map_;
+};
+
+}  // namespace grpc
+
+#endif  // GRPCXX_IMPL_CODEGEN_METADATA_MAP_H

include/grpc++/impl/codegen/server_context.h

@@ -39,6 +39,7 @@
 
 #include <grpc++/impl/codegen/config.h>
 #include <grpc++/impl/codegen/create_auth_context.h>
+#include <grpc++/impl/codegen/metadata_map.h>
 #include <grpc++/impl/codegen/security/auth_context.h>
 #include <grpc++/impl/codegen/string_ref.h>
 #include <grpc++/impl/codegen/time.h>
@@ -123,7 +124,7 @@ class ServerContext {
 
   const std::multimap<grpc::string_ref, grpc::string_ref>& client_metadata()
       const {
-    return client_metadata_;
+    return *client_metadata_.map();
   }
 
   grpc_compression_level compression_level() const {
@@ -223,7 +224,7 @@ class ServerContext {
   CompletionQueue* cq_;
   bool sent_initial_metadata_;
   mutable std::shared_ptr<const AuthContext> auth_context_;
-  std::multimap<grpc::string_ref, grpc::string_ref> client_metadata_;
+  MetadataMap client_metadata_;
   std::multimap<grpc::string, grpc::string> initial_metadata_;
   std::multimap<grpc::string, grpc::string> trailing_metadata_;
 

include/grpc++/impl/codegen/server_interface.h

@@ -152,7 +152,6 @@ class ServerInterface : public CallHook {
     void* const tag_;
     const bool delete_on_finalize_;
     grpc_call* call_;
-    grpc_metadata_array initial_metadata_array_;
   };
 
   class RegisteredAsyncRequest : public BaseAsyncRequest {

include/grpc++/impl/codegen/slice.h

@@ -0,0 +1,65 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef GRPCXX_IMPL_CODEGEN_SLICE_H
+#define GRPCXX_IMPL_CODEGEN_SLICE_H
+
+#include <grpc++/impl/codegen/core_codegen_interface.h>
+#include <grpc++/impl/codegen/string_ref.h>
+
+namespace grpc {
+
+inline grpc::string_ref StringRefFromSlice(const grpc_slice* slice) {
+  return grpc::string_ref(
+      reinterpret_cast<const char*>(GRPC_SLICE_START_PTR(*slice)),
+      GRPC_SLICE_LENGTH(*slice));
+}
+
+inline grpc::string StringFromCopiedSlice(grpc_slice slice) {
+  return grpc::string(reinterpret_cast<char*>(GRPC_SLICE_START_PTR(slice)),
+                      GRPC_SLICE_LENGTH(slice));
+}
+
+inline grpc_slice SliceReferencingString(const grpc::string& str) {
+  return g_core_codegen_interface->grpc_slice_from_static_buffer(str.data(),
+                                                                 str.length());
+}
+
+inline grpc_slice SliceFromCopiedString(const grpc::string& str) {
+  return g_core_codegen_interface->grpc_slice_from_copied_buffer(str.data(),
+                                                                 str.length());
+}
+
+}  // namespace grpc
+
+#endif  // GRPCXX_IMPL_CODEGEN_SLICE_H

include/grpc++/support/channel_arguments.h

@@ -88,6 +88,10 @@ class ChannelArguments {
   /// The given buffer pool will be attached to the constructed channel
   void SetResourceQuota(const ResourceQuota& resource_quota);
 
+  /// Sets the max receive and send message sizes.
+  void SetMaxReceiveMessageSize(int size);
+  void SetMaxSendMessageSize(int size);
+
   /// Set LB policy name.
   /// Note that if the name resolver returns only balancer addresses, the
   /// grpclb LB policy will be used, regardless of what is specified here.

include/grpc/compression.h

@@ -34,11 +34,12 @@
 #ifndef GRPC_COMPRESSION_H
 #define GRPC_COMPRESSION_H
 
-#include <stdlib.h>
-
 #include <grpc/impl/codegen/port_platform.h>
 
+#include <stdlib.h>
+
 #include <grpc/impl/codegen/compression_types.h>
+#include <grpc/slice.h>
 
 #ifdef __cplusplus
 extern "C" {
@@ -48,8 +49,7 @@ extern "C" {
  * grpc_compression_algorithm instance, updating \a algorithm. Returns 1 upon
  * success, 0 otherwise. */
 GRPCAPI int grpc_compression_algorithm_parse(
-    const char *name, size_t name_length,
-    grpc_compression_algorithm *algorithm);
+    grpc_slice value, grpc_compression_algorithm *algorithm);
 
 /** Updates \a name with the encoding name corresponding to a valid \a
  * algorithm. Note that \a name is statically allocated and must *not* be freed.

include/grpc/grpc.h

@@ -178,8 +178,8 @@ GRPCAPI void grpc_channel_watch_connectivity_state(
     possible values). */
 GRPCAPI grpc_call *grpc_channel_create_call(
     grpc_channel *channel, grpc_call *parent_call, uint32_t propagation_mask,
-    grpc_completion_queue *completion_queue, const char *method,
-    const char *host, gpr_timespec deadline, void *reserved);
+    grpc_completion_queue *completion_queue, grpc_slice method,
+    const grpc_slice *host, gpr_timespec deadline, void *reserved);
 
 /** Ping the channels peer (load balanced channels will select one sub-channel
     to ping); if the channel is not connected, posts a failed. */
@@ -402,14 +402,14 @@ GRPCAPI void grpc_server_destroy(grpc_server *server);
 GRPCAPI int grpc_tracer_set_enabled(const char *name, int enabled);
 
 /** Check whether a metadata key is legal (will be accepted by core) */
-GRPCAPI int grpc_header_key_is_legal(const char *key, size_t length);
+GRPCAPI int grpc_header_key_is_legal(grpc_slice slice);
 
 /** Check whether a non-binary metadata value is legal (will be accepted by
     core) */
-GRPCAPI int grpc_header_nonbin_value_is_legal(const char *value, size_t length);
+GRPCAPI int grpc_header_nonbin_value_is_legal(grpc_slice slice);
 
 /** Check whether a metadata key corresponds to a binary value */
-GRPCAPI int grpc_is_binary_header(const char *key, size_t length);
+GRPCAPI int grpc_is_binary_header(grpc_slice slice);
 
 /** Convert grpc_call_error values to a string */
 GRPCAPI const char *grpc_call_error_to_string(grpc_call_error error);

include/grpc/impl/codegen/grpc_types.h

@@ -294,9 +294,11 @@ typedef enum grpc_call_error {
 
 /** A single metadata element */
 typedef struct grpc_metadata {
-  const char *key;
-  const char *value;
-  size_t value_length;
+  /* the key, value values are expected to line up with grpc_mdelem: if changing
+     them, update metadata.h at the same time. */
+  grpc_slice key;
+  grpc_slice value;
+
   uint32_t flags;
 
   /** The following fields are reserved for grpc internal use.
@@ -338,10 +340,8 @@ typedef struct {
 } grpc_metadata_array;
 
 typedef struct {
-  char *method;
-  size_t method_capacity;
-  char *host;
-  size_t host_capacity;
+  grpc_slice method;
+  grpc_slice host;
   gpr_timespec deadline;
   uint32_t flags;
   void *reserved;
@@ -423,7 +423,10 @@ typedef struct grpc_op {
       size_t trailing_metadata_count;
       grpc_metadata *trailing_metadata;
       grpc_status_code status;
-      const char *status_details;
+      /* optional: set to NULL if no details need sending, non-NULL if they do
+       * pointer will not be retained past the start_batch call
+       */
+      grpc_slice *status_details;
     } send_status_from_server;
     /** ownership of the array is with the caller, but ownership of the elements
         stays with the call object (ie key, value members are owned by the call
@@ -444,28 +447,7 @@ typedef struct grpc_op {
           value, or reuse it in a future op. */
       grpc_metadata_array *trailing_metadata;
       grpc_status_code *status;
-      /** status_details is a buffer owned by the application before the op
-          completes and after the op has completed. During the operation
-          status_details may be reallocated to a size larger than
-          *status_details_capacity, in which case *status_details_capacity will
-          be updated with the new array capacity.
-
-          Pre-allocating space:
-          size_t my_capacity = 8;
-          char *my_details = gpr_malloc(my_capacity);
-          x.status_details = &my_details;
-          x.status_details_capacity = &my_capacity;
-
-          Not pre-allocating space:
-          size_t my_capacity = 0;
-          char *my_details = NULL;
-          x.status_details = &my_details;
-          x.status_details_capacity = &my_capacity;
-
-          After the call:
-          gpr_free(my_details); */
-      char **status_details;
-      size_t *status_details_capacity;
+      grpc_slice *status_details;
     } recv_status_on_client;
     struct {
       /** out argument, set to 1 if the call failed in any way (seen as a

include/grpc/impl/codegen/slice.h

@@ -40,6 +40,8 @@
 #include <grpc/impl/codegen/exec_ctx_fwd.h>
 #include <grpc/impl/codegen/gpr_slice.h>
 
+typedef struct grpc_slice grpc_slice;
+
 /* Slice API
 
    A slice represents a contiguous reference counted array of bytes.
@@ -53,14 +55,25 @@
    reference ownership semantics (who should call unref?) and mutability
    constraints (is the callee allowed to modify the slice?) */
 
+typedef struct grpc_slice_refcount_vtable {
+  void (*ref)(void *);
+  void (*unref)(grpc_exec_ctx *exec_ctx, void *);
+  int (*eq)(grpc_slice a, grpc_slice b);
+  uint32_t (*hash)(grpc_slice slice);
+} grpc_slice_refcount_vtable;
+
 /* Reference count container for grpc_slice. Contains function pointers to
    increment and decrement reference counts. Implementations should cleanup
    when the reference count drops to zero.
    Typically client code should not touch this, and use grpc_slice_malloc,
    grpc_slice_new, or grpc_slice_new_with_len instead. */
 typedef struct grpc_slice_refcount {
-  void (*ref)(void *);
-  void (*unref)(grpc_exec_ctx *exec_ctx, void *);
+  const grpc_slice_refcount_vtable *vtable;
+  /* If a subset of this slice is taken, use this pointer for the refcount.
+     Typically points back to the refcount itself, however iterning
+     implementations can use this to avoid a verification step on each hash
+     or equality check */
+  struct grpc_slice_refcount *sub_refcount;
 } grpc_slice_refcount;
 
 #define GRPC_SLICE_INLINED_SIZE (sizeof(size_t) + sizeof(uint8_t *) - 1)
@@ -74,7 +87,7 @@ typedef struct grpc_slice_refcount {
 
    If the slice does not have a refcount, it represents an inlined small piece
    of data that is copied by value. */
-typedef struct grpc_slice {
+struct grpc_slice {
   struct grpc_slice_refcount *refcount;
   union {
     struct {
@@ -86,7 +99,7 @@ typedef struct grpc_slice {
       uint8_t bytes[GRPC_SLICE_INLINED_SIZE];
     } inlined;
   } data;
-} grpc_slice;
+};
 
 #define GRPC_SLICE_BUFFER_INLINE_ELEMENTS 8
 

include/grpc/slice.h

@@ -76,6 +76,12 @@ GPRAPI grpc_slice grpc_slice_new_with_len(void *p, size_t len,
    Aborts if malloc() fails. */
 GPRAPI grpc_slice grpc_slice_malloc(size_t length);
 
+/* Intern a slice:
+
+   The return value for two invocations of this function with  the same sequence
+   of bytes is a slice which points to the same memory. */
+GPRAPI grpc_slice grpc_slice_intern(grpc_slice slice);
+
 /* Create a slice by copying a string.
    Does not preserve null terminators.
    Equivalent to:
@@ -93,6 +99,9 @@ GPRAPI grpc_slice grpc_slice_from_copied_buffer(const char *source, size_t len);
 /* Create a slice pointing to constant memory */
 GPRAPI grpc_slice grpc_slice_from_static_string(const char *source);
 
+/* Create a slice pointing to constant memory */
+GPRAPI grpc_slice grpc_slice_from_static_buffer(const void *source, size_t len);
+
 /* Return a result slice derived from s, which shares a ref count with s, where
    result.data==s.data+begin, and result.length==end-begin.
    The ref count of s is increased by one.
@@ -113,18 +122,45 @@ GPRAPI grpc_slice grpc_slice_split_tail(grpc_slice *s, size_t split);
    Requires s intialized, split <= s.length */
 GPRAPI grpc_slice grpc_slice_split_head(grpc_slice *s, size_t split);
 
-GPRAPI grpc_slice gpr_empty_slice(void);
+GPRAPI grpc_slice grpc_empty_slice(void);
+
+GPRAPI uint32_t grpc_slice_default_hash_impl(grpc_slice s);
+GPRAPI int grpc_slice_default_eq_impl(grpc_slice a, grpc_slice b);
+
+GPRAPI int grpc_slice_eq(grpc_slice a, grpc_slice b);
 
 /* Returns <0 if a < b, ==0 if a == b, >0 if a > b
    The order is arbitrary, and is not guaranteed to be stable across different
    versions of the API. */
 GPRAPI int grpc_slice_cmp(grpc_slice a, grpc_slice b);
 GPRAPI int grpc_slice_str_cmp(grpc_slice a, const char *b);
+GPRAPI int grpc_slice_buf_cmp(grpc_slice a, const void *b, size_t blen);
+
+/* return non-zero if the first blen bytes of a are equal to b */
+GPRAPI int grpc_slice_buf_start_eq(grpc_slice a, const void *b, size_t blen);
+
+/* return the index of the last instance of \a c in \a s, or -1 if not found */
+GPRAPI int grpc_slice_rchr(grpc_slice s, char c);
+GPRAPI int grpc_slice_chr(grpc_slice s, char c);
+
+/* return the index of the first occurance of \a needle in \a haystack, or -1 if
+ * it's not found */
+GPRAPI int grpc_slice_slice(grpc_slice haystack, grpc_slice needle);
+
+GPRAPI uint32_t grpc_slice_hash(grpc_slice s);
 
 /* Do two slices point at the same memory, with the same length
    If a or b is inlined, actually compares data */
 GPRAPI int grpc_slice_is_equivalent(grpc_slice a, grpc_slice b);
 
+/* Return a slice pointing to newly allocated memory that has the same contents
+ * as \a s */
+GPRAPI grpc_slice grpc_slice_dup(grpc_slice a);
+
+/* Return a copy of slice as a C string. Offers no protection against embedded
+   NULL's. Returned string must be freed with gpr_free. */
+GPRAPI char *grpc_slice_to_c_string(grpc_slice s);
+
 #ifdef __cplusplus
 }
 #endif

package.xml

@@ -200,6 +200,7 @@
     <file baseinstalldir="/" name="src/core/lib/iomgr/endpoint.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/iomgr/endpoint_pair.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/iomgr/error.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/iomgr/error_internal.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/iomgr/ev_epoll_linux.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/iomgr/ev_poll_posix.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/iomgr/ev_posix.h" role="src" />
@@ -252,6 +253,7 @@
     <file baseinstalldir="/" name="src/core/lib/json/json_reader.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/json/json_writer.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/slice/percent_encoding.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/slice/slice_hash_table.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/slice/slice_internal.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/slice/slice_string_helpers.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/surface/api_trace.h" role="src" />
@@ -265,14 +267,17 @@
     <file baseinstalldir="/" name="src/core/lib/surface/init.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/surface/lame_client.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/surface/server.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/surface/validate_metadata.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/transport/byte_stream.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/transport/connectivity_state.h" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/transport/mdstr_hash_table.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/transport/error_utils.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/transport/http2_errors.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/transport/metadata.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/transport/metadata_batch.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/transport/pid_controller.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/transport/service_config.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/transport/static_metadata.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/transport/status_conversion.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/transport/timeout_encoding.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/transport/transport.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/transport/transport_impl.h" role="src" />
@@ -289,11 +294,9 @@
     <file baseinstalldir="/" name="src/core/ext/transport/chttp2/transport/hpack_encoder.h" role="src" />
     <file baseinstalldir="/" name="src/core/ext/transport/chttp2/transport/hpack_parser.h" role="src" />
     <file baseinstalldir="/" name="src/core/ext/transport/chttp2/transport/hpack_table.h" role="src" />
-    <file baseinstalldir="/" name="src/core/ext/transport/chttp2/transport/http2_errors.h" role="src" />
     <file baseinstalldir="/" name="src/core/ext/transport/chttp2/transport/huffsyms.h" role="src" />
     <file baseinstalldir="/" name="src/core/ext/transport/chttp2/transport/incoming_metadata.h" role="src" />
     <file baseinstalldir="/" name="src/core/ext/transport/chttp2/transport/internal.h" role="src" />
-    <file baseinstalldir="/" name="src/core/ext/transport/chttp2/transport/status_conversion.h" role="src" />
     <file baseinstalldir="/" name="src/core/ext/transport/chttp2/transport/stream_map.h" role="src" />
     <file baseinstalldir="/" name="src/core/ext/transport/chttp2/transport/varint.h" role="src" />
     <file baseinstalldir="/" name="src/core/ext/transport/chttp2/alpn/alpn.h" role="src" />
@@ -443,6 +446,8 @@
     <file baseinstalldir="/" name="src/core/lib/slice/percent_encoding.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/slice/slice.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/slice/slice_buffer.c" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/slice/slice_hash_table.c" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/slice/slice_intern.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/slice/slice_string_helpers.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/surface/alarm.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/surface/api_trace.c" role="src" />
@@ -464,12 +469,13 @@
     <file baseinstalldir="/" name="src/core/lib/surface/version.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/transport/byte_stream.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/transport/connectivity_state.c" role="src" />
-    <file baseinstalldir="/" name="src/core/lib/transport/mdstr_hash_table.c" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/transport/error_utils.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/transport/metadata.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/transport/metadata_batch.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/transport/pid_controller.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/transport/service_config.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/transport/static_metadata.c" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/transport/status_conversion.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/transport/timeout_encoding.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/transport/transport.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/transport/transport_op_string.c" role="src" />
@@ -490,7 +496,6 @@
     <file baseinstalldir="/" name="src/core/ext/transport/chttp2/transport/huffsyms.c" role="src" />
     <file baseinstalldir="/" name="src/core/ext/transport/chttp2/transport/incoming_metadata.c" role="src" />
     <file baseinstalldir="/" name="src/core/ext/transport/chttp2/transport/parsing.c" role="src" />
-    <file baseinstalldir="/" name="src/core/ext/transport/chttp2/transport/status_conversion.c" role="src" />
     <file baseinstalldir="/" name="src/core/ext/transport/chttp2/transport/stream_lists.c" role="src" />
     <file baseinstalldir="/" name="src/core/ext/transport/chttp2/transport/stream_map.c" role="src" />
     <file baseinstalldir="/" name="src/core/ext/transport/chttp2/transport/varint.c" role="src" />

src/compiler/cpp_generator.cc

@@ -1218,13 +1218,15 @@ void PrintSourceService(Printer *printer, const Service *service,
                         std::map<grpc::string, grpc::string> *vars) {
   (*vars)["Service"] = service->name();
 
-  printer->Print(*vars,
-                 "static const char* $prefix$$Service$_method_names[] = {\n");
-  for (int i = 0; i < service->method_count(); ++i) {
-    (*vars)["Method"] = service->method(i).get()->name();
-    printer->Print(*vars, "  \"/$Package$$Service$/$Method$\",\n");
+  if (service->method_count() > 0) {
+    printer->Print(*vars,
+                   "static const char* $prefix$$Service$_method_names[] = {\n");
+    for (int i = 0; i < service->method_count(); ++i) {
+      (*vars)["Method"] = service->method(i).get()->name();
+      printer->Print(*vars, "  \"/$Package$$Service$/$Method$\",\n");
+    }
+    printer->Print(*vars, "};\n\n");
   }
-  printer->Print(*vars, "};\n\n");
 
   printer->Print(*vars,
                  "std::unique_ptr< $ns$$Service$::Stub> $ns$$Service$::NewStub("
@@ -1272,7 +1274,6 @@ void PrintSourceService(Printer *printer, const Service *service,
 
   printer->Print(*vars, "$ns$$Service$::Service::Service() {\n");
   printer->Indent();
-  printer->Print(*vars, "(void)$prefix$$Service$_method_names;\n");
   for (int i = 0; i < service->method_count(); ++i) {
     auto method = service->method(i);
     (*vars)["Idx"] = as_string(i);

src/core/ext/census/gen/census.pb.h

@@ -292,4 +292,4 @@ extern const pb_field_t google_census_Metric_fields[5];
 } /* extern "C" */
 #endif
 
-#endif
+#endif /* GRPC_CORE_EXT_CENSUS_GEN_CENSUS_PB_H */

src/core/ext/census/gen/trace_context.pb.h

@@ -96,4 +96,4 @@ extern const pb_field_t google_trace_TraceContext_fields[4];
 } /* extern "C" */
 #endif
 
-#endif
+#endif /* GRPC_CORE_EXT_CENSUS_GEN_TRACE_CONTEXT_PB_H */

src/core/ext/census/grpc_filter.c

@@ -67,9 +67,7 @@ static void extract_and_annotate_method_tag(grpc_metadata_batch *md,
                                             channel_data *chand) {
   grpc_linked_mdelem *m;
   for (m = md->list.head; m != NULL; m = m->next) {
-    if (m->md->key == GRPC_MDSTR_PATH) {
-      gpr_log(GPR_DEBUG, "%s",
-              (const char *)GRPC_SLICE_START_PTR(m->md->value->slice));
+    if (grpc_slice_eq(GRPC_MDKEY(m->md), GRPC_MDSTR_PATH)) {
       /* Add method tag here */
     }
   }

src/core/ext/client_channel/client_channel.c

@@ -52,6 +52,7 @@
 #include "src/core/lib/iomgr/iomgr.h"
 #include "src/core/lib/iomgr/polling_entity.h"
 #include "src/core/lib/profiling/timers.h"
+#include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/support/string.h"
 #include "src/core/lib/surface/channel.h"
 #include "src/core/lib/transport/connectivity_state.h"
@@ -87,7 +88,7 @@ static void method_parameters_free(grpc_exec_ctx *exec_ctx, void *p) {
   gpr_free(p);
 }
 
-static const grpc_mdstr_hash_table_vtable method_parameters_vtable = {
+static const grpc_slice_hash_table_vtable method_parameters_vtable = {
     method_parameters_free, method_parameters_copy};
 
 static void *method_parameters_create_from_json(const grpc_json *json) {
@@ -165,7 +166,7 @@ typedef struct client_channel_channel_data {
   /** service config in JSON form */
   char *service_config_json;
   /** maps method names to method_parameters structs */
-  grpc_mdstr_hash_table *method_params_table;
+  grpc_slice_hash_table *method_params_table;
   /** incoming resolver result - set by resolver.next() */
   grpc_channel_args *resolver_result;
   /** a list of closures that are all waiting for config to come in */
@@ -267,7 +268,7 @@ static void on_resolver_result_changed(grpc_exec_ctx *exec_ctx, void *arg,
   char *lb_policy_name = NULL;
   grpc_lb_policy *lb_policy = NULL;
   grpc_lb_policy *old_lb_policy;
-  grpc_mdstr_hash_table *method_params_table = NULL;
+  grpc_slice_hash_table *method_params_table = NULL;
   grpc_connectivity_state state = GRPC_CHANNEL_TRANSIENT_FAILURE;
   bool exit_idle = false;
   grpc_error *state_error = GRPC_ERROR_CREATE("No load balancing policy");
@@ -362,7 +363,7 @@ static void on_resolver_result_changed(grpc_exec_ctx *exec_ctx, void *arg,
     chand->service_config_json = service_config_json;
   }
   if (chand->method_params_table != NULL) {
-    grpc_mdstr_hash_table_unref(exec_ctx, chand->method_params_table);
+    grpc_slice_hash_table_unref(exec_ctx, chand->method_params_table);
   }
   chand->method_params_table = method_params_table;
   if (lb_policy != NULL) {
@@ -558,7 +559,7 @@ static void cc_destroy_channel_elem(grpc_exec_ctx *exec_ctx,
   gpr_free(chand->lb_policy_name);
   gpr_free(chand->service_config_json);
   if (chand->method_params_table != NULL) {
-    grpc_mdstr_hash_table_unref(exec_ctx, chand->method_params_table);
+    grpc_slice_hash_table_unref(exec_ctx, chand->method_params_table);
   }
   grpc_connectivity_state_destroy(exec_ctx, &chand->state_tracker);
   grpc_pollset_set_destroy(chand->interested_parties);
@@ -593,7 +594,7 @@ typedef struct client_channel_call_data {
   // to avoid this without breaking the grpc_deadline_state abstraction.
   grpc_deadline_state deadline_state;
 
-  grpc_mdstr *path;  // Request path.
+  grpc_slice path;  // Request path.
   gpr_timespec call_start_time;
   gpr_timespec deadline;
   wait_for_ready_value wait_for_ready_from_service_config;
@@ -997,10 +998,10 @@ static void read_service_config(grpc_exec_ctx *exec_ctx, void *arg,
   if (error == GRPC_ERROR_NONE) {
     // Get the method config table from channel data.
     gpr_mu_lock(&chand->mu);
-    grpc_mdstr_hash_table *method_params_table = NULL;
+    grpc_slice_hash_table *method_params_table = NULL;
     if (chand->method_params_table != NULL) {
       method_params_table =
-          grpc_mdstr_hash_table_ref(chand->method_params_table);
+          grpc_slice_hash_table_ref(chand->method_params_table);
     }
     gpr_mu_unlock(&chand->mu);
     // If the method config table was present, use it.
@@ -1029,7 +1030,7 @@ static void read_service_config(grpc_exec_ctx *exec_ctx, void *arg,
           gpr_mu_unlock(&calld->mu);
         }
       }
-      grpc_mdstr_hash_table_unref(exec_ctx, method_params_table);
+      grpc_slice_hash_table_unref(exec_ctx, method_params_table);
     }
   }
   GRPC_CALL_STACK_UNREF(exec_ctx, calld->owning_call, "read_service_config");
@@ -1043,7 +1044,7 @@ static grpc_error *cc_init_call_elem(grpc_exec_ctx *exec_ctx,
   call_data *calld = elem->call_data;
   // Initialize data members.
   grpc_deadline_state_init(exec_ctx, elem, args->call_stack);
-  calld->path = GRPC_MDSTR_REF(args->path);
+  calld->path = grpc_slice_ref_internal(args->path);
   calld->call_start_time = args->start_time;
   calld->deadline = gpr_convert_clock_type(args->deadline, GPR_CLOCK_MONOTONIC);
   calld->wait_for_ready_from_service_config = WAIT_FOR_READY_UNSET;
@@ -1067,8 +1068,8 @@ static grpc_error *cc_init_call_elem(grpc_exec_ctx *exec_ctx,
   if (chand->lb_policy != NULL) {
     // We already have a resolver result, so check for service config.
     if (chand->method_params_table != NULL) {
-      grpc_mdstr_hash_table *method_params_table =
-          grpc_mdstr_hash_table_ref(chand->method_params_table);
+      grpc_slice_hash_table *method_params_table =
+          grpc_slice_hash_table_ref(chand->method_params_table);
       gpr_mu_unlock(&chand->mu);
       method_parameters *method_params = grpc_method_config_table_get(
           exec_ctx, method_params_table, args->path);
@@ -1084,7 +1085,7 @@ static grpc_error *cc_init_call_elem(grpc_exec_ctx *exec_ctx,
               method_params->wait_for_ready;
         }
       }
-      grpc_mdstr_hash_table_unref(exec_ctx, method_params_table);
+      grpc_slice_hash_table_unref(exec_ctx, method_params_table);
     } else {
       gpr_mu_unlock(&chand->mu);
     }
@@ -1113,7 +1114,7 @@ static void cc_destroy_call_elem(grpc_exec_ctx *exec_ctx,
                                  void *and_free_memory) {
   call_data *calld = elem->call_data;
   grpc_deadline_state_destroy(exec_ctx, elem);
-  GRPC_MDSTR_UNREF(exec_ctx, calld->path);
+  grpc_slice_unref_internal(exec_ctx, calld->path);
   GRPC_ERROR_UNREF(calld->cancel_error);
   grpc_subchannel_call *call = GET_CALL(calld);
   if (call != NULL && call != CANCELLED_CALL) {

src/core/ext/client_channel/resolver_registry.h

@@ -60,7 +60,9 @@ void grpc_register_resolver_type(grpc_resolver_factory *factory);
     return it.
     If a resolver factory was not found, return NULL.
     \a args is a set of channel arguments to be included in the result
-    (typically the set of arguments passed in from the client API). */
+    (typically the set of arguments passed in from the client API).
+    \a pollset_set is used to drive IO in the name resolution process, it
+    should not be NULL. */
 grpc_resolver *grpc_resolver_create(grpc_exec_ctx *exec_ctx, const char *target,
                                     const grpc_channel_args *args,
                                     grpc_pollset_set *pollset_set);

src/core/ext/client_channel/subchannel.c

@@ -625,9 +625,8 @@ static void publish_transport_locked(grpc_exec_ctx *exec_ctx,
   grpc_error *error = grpc_channel_stack_builder_finish(
       exec_ctx, builder, 0, 1, connection_destroy, NULL, (void **)&con);
   if (error != GRPC_ERROR_NONE) {
-    const char *msg = grpc_error_string(error);
-    gpr_log(GPR_ERROR, "error initializing subchannel stack: %s", msg);
-    grpc_error_free_string(msg);
+    gpr_log(GPR_ERROR, "error initializing subchannel stack: %s",
+            grpc_error_string(error));
     GRPC_ERROR_UNREF(error);
     abort(); /* TODO(ctiller): what to do here? */
   }
@@ -692,7 +691,6 @@ static void subchannel_connected(grpc_exec_ctx *exec_ctx, void *arg,
 
     const char *errmsg = grpc_error_string(error);
     gpr_log(GPR_INFO, "Connect failed: %s", errmsg);
-    grpc_error_free_string(errmsg);
 
     maybe_start_connecting_locked(exec_ctx, c);
     GRPC_SUBCHANNEL_WEAK_UNREF(exec_ctx, c, "connecting");
@@ -751,7 +749,7 @@ grpc_connected_subchannel *grpc_subchannel_get_connected_subchannel(
 
 grpc_error *grpc_connected_subchannel_create_call(
     grpc_exec_ctx *exec_ctx, grpc_connected_subchannel *con,
-    grpc_polling_entity *pollent, grpc_mdstr *path, gpr_timespec start_time,
+    grpc_polling_entity *pollent, grpc_slice path, gpr_timespec start_time,
     gpr_timespec deadline, grpc_subchannel_call **call) {
   grpc_channel_stack *chanstk = CHANNEL_STACK_FROM_CONNECTION(con);
   *call = gpr_malloc(sizeof(grpc_subchannel_call) + chanstk->call_stack_size);
@@ -763,7 +761,7 @@ grpc_error *grpc_connected_subchannel_create_call(
   if (error != GRPC_ERROR_NONE) {
     const char *error_string = grpc_error_string(error);
     gpr_log(GPR_ERROR, "error: %s", error_string);
-    grpc_error_free_string(error_string);
+
     gpr_free(*call);
     return error;
   }

src/core/ext/client_channel/subchannel.h

@@ -114,7 +114,7 @@ void grpc_subchannel_call_unref(grpc_exec_ctx *exec_ctx,
 /** construct a subchannel call */
 grpc_error *grpc_connected_subchannel_create_call(
     grpc_exec_ctx *exec_ctx, grpc_connected_subchannel *connected_subchannel,
-    grpc_polling_entity *pollent, grpc_mdstr *path, gpr_timespec start_time,
+    grpc_polling_entity *pollent, grpc_slice path, gpr_timespec start_time,
     gpr_timespec deadline, grpc_subchannel_call **subchannel_call);
 
 /** process a transport level op */

src/core/ext/lb_policy/grpclb/grpclb.c

@@ -135,13 +135,13 @@ int grpc_lb_glb_trace = 0;
 
 /* add lb_token of selected subchannel (address) to the call's initial
  * metadata */
-static void initial_metadata_add_lb_token(
-    grpc_metadata_batch *initial_metadata,
-    grpc_linked_mdelem *lb_token_mdelem_storage, grpc_mdelem *lb_token) {
+static grpc_error *initial_metadata_add_lb_token(
+    grpc_exec_ctx *exec_ctx, grpc_metadata_batch *initial_metadata,
+    grpc_linked_mdelem *lb_token_mdelem_storage, grpc_mdelem lb_token) {
   GPR_ASSERT(lb_token_mdelem_storage != NULL);
-  GPR_ASSERT(lb_token != NULL);
-  grpc_metadata_batch_add_tail(initial_metadata, lb_token_mdelem_storage,
-                               lb_token);
+  GPR_ASSERT(!GRPC_MDISNULL(lb_token));
+  return grpc_metadata_batch_add_tail(exec_ctx, initial_metadata,
+                                      lb_token_mdelem_storage, lb_token);
 }
 
 typedef struct wrapped_rr_closure_arg {
@@ -161,7 +161,7 @@ typedef struct wrapped_rr_closure_arg {
   grpc_connected_subchannel **target;
 
   /* the LB token associated with the pick */
-  grpc_mdelem *lb_token;
+  grpc_mdelem lb_token;
 
   /* storage for the lb token initial metadata mdelem */
   grpc_linked_mdelem *lb_token_mdelem_storage;
@@ -188,8 +188,8 @@ static void wrapped_rr_closure(grpc_exec_ctx *exec_ctx, void *arg,
      * addresses failed to connect). There won't be any user_data/token
      * available */
     if (*wc_arg->target != NULL) {
-      if (wc_arg->lb_token != NULL) {
-        initial_metadata_add_lb_token(wc_arg->initial_metadata,
+      if (!GRPC_MDISNULL(wc_arg->lb_token)) {
+        initial_metadata_add_lb_token(exec_ctx, wc_arg->initial_metadata,
                                       wc_arg->lb_token_mdelem_storage,
                                       GRPC_MDELEM_REF(wc_arg->lb_token));
       } else {
@@ -345,8 +345,7 @@ typedef struct glb_lb_policy {
 
   /* call status code and details, set in lb_on_server_status_received() */
   grpc_status_code lb_call_status;
-  char *lb_call_status_details;
-  size_t lb_call_status_details_capacity;
+  grpc_slice lb_call_status_details;
 
   /** LB call retry backoff state */
   gpr_backoff lb_call_backoff_state;
@@ -388,10 +387,14 @@ static bool is_server_valid(const grpc_grpclb_server *server, size_t idx,
 
 /* vtable for LB tokens in grpc_lb_addresses. */
 static void *lb_token_copy(void *token) {
-  return token == NULL ? NULL : GRPC_MDELEM_REF(token);
+  return token == NULL
+             ? NULL
+             : (void *)GRPC_MDELEM_REF((grpc_mdelem){(uintptr_t)token}).payload;
 }
 static void lb_token_destroy(grpc_exec_ctx *exec_ctx, void *token) {
-  if (token != NULL) GRPC_MDELEM_UNREF(exec_ctx, token);
+  if (token != NULL) {
+    GRPC_MDELEM_UNREF(exec_ctx, (grpc_mdelem){(uintptr_t)token});
+  }
 }
 static int lb_token_cmp(void *token1, void *token2) {
   if (token1 > token2) return 1;
@@ -459,10 +462,11 @@ static grpc_lb_addresses *process_serverlist_locked(
           GPR_ARRAY_SIZE(server->load_balance_token);
       const size_t lb_token_length =
           strnlen(server->load_balance_token, lb_token_max_length);
-      grpc_mdstr *lb_token_mdstr = grpc_mdstr_from_buffer(
-          (uint8_t *)server->load_balance_token, lb_token_length);
-      user_data = grpc_mdelem_from_metadata_strings(
-          exec_ctx, GRPC_MDSTR_LB_TOKEN, lb_token_mdstr);
+      grpc_slice lb_token_mdstr = grpc_slice_from_copied_buffer(
+          server->load_balance_token, lb_token_length);
+      user_data = (void *)grpc_mdelem_from_slices(exec_ctx, GRPC_MDSTR_LB_TOKEN,
+                                                  lb_token_mdstr)
+                      .payload;
     } else {
       char *uri = grpc_sockaddr_to_uri(&addr);
       gpr_log(GPR_INFO,
@@ -470,7 +474,7 @@ static grpc_lb_addresses *process_serverlist_locked(
               "be used instead",
               uri);
       gpr_free(uri);
-      user_data = GRPC_MDELEM_LB_TOKEN_EMPTY;
+      user_data = (void *)GRPC_MDELEM_LB_TOKEN_EMPTY.payload;
     }
 
     grpc_lb_addresses_set_address(lb_addresses, addr_idx, &addr.addr, addr.len,
@@ -564,7 +568,7 @@ static bool pick_from_internal_rr_locked(
     GRPC_LB_POLICY_UNREF(exec_ctx, wc_arg->rr_policy, "glb_pick_sync");
 
     /* add the load reporting initial metadata */
-    initial_metadata_add_lb_token(pick_args->initial_metadata,
+    initial_metadata_add_lb_token(exec_ctx, pick_args->initial_metadata,
                                   pick_args->lb_token_mdelem_storage,
                                   GRPC_MDELEM_REF(wc_arg->lb_token));
 
@@ -1103,11 +1107,12 @@ static void lb_call_init_locked(grpc_exec_ctx *exec_ctx,
   /* Note the following LB call progresses every time there's activity in \a
    * glb_policy->base.interested_parties, which is comprised of the polling
    * entities from \a client_channel. */
+  grpc_slice host = grpc_slice_from_copied_string(glb_policy->server_name);
   glb_policy->lb_call = grpc_channel_create_pollset_set_call(
       exec_ctx, glb_policy->lb_channel, NULL, GRPC_PROPAGATE_DEFAULTS,
       glb_policy->base.interested_parties,
-      "/grpc.lb.v1.LoadBalancer/BalanceLoad", glb_policy->server_name,
-      glb_policy->deadline, NULL);
+      GRPC_MDSTR_SLASH_GRPC_DOT_LB_DOT_V1_DOT_LOADBALANCER_SLASH_BALANCELOAD,
+      &host, glb_policy->deadline, NULL);
 
   grpc_metadata_array_init(&glb_policy->lb_initial_metadata_recv);
   grpc_metadata_array_init(&glb_policy->lb_trailing_metadata_recv);
@@ -1120,9 +1125,6 @@ static void lb_call_init_locked(grpc_exec_ctx *exec_ctx,
   grpc_slice_unref_internal(exec_ctx, request_payload_slice);
   grpc_grpclb_request_destroy(request);
 
-  glb_policy->lb_call_status_details = NULL;
-  glb_policy->lb_call_status_details_capacity = 0;
-
   grpc_closure_init(&glb_policy->lb_on_server_status_received,
                     lb_on_server_status_received, glb_policy,
                     grpc_schedule_on_exec_ctx);
@@ -1138,7 +1140,8 @@ static void lb_call_init_locked(grpc_exec_ctx *exec_ctx,
                    GRPC_GRPCLB_RECONNECT_MAX_BACKOFF_SECONDS * 1000);
 }
 
-static void lb_call_destroy_locked(glb_lb_policy *glb_policy) {
+static void lb_call_destroy_locked(grpc_exec_ctx *exec_ctx,
+                                   glb_lb_policy *glb_policy) {
   GPR_ASSERT(glb_policy->lb_call != NULL);
   grpc_call_destroy(glb_policy->lb_call);
   glb_policy->lb_call = NULL;
@@ -1147,7 +1150,7 @@ static void lb_call_destroy_locked(glb_lb_policy *glb_policy) {
   grpc_metadata_array_destroy(&glb_policy->lb_trailing_metadata_recv);
 
   grpc_byte_buffer_destroy(glb_policy->lb_request_payload);
-  gpr_free(glb_policy->lb_call_status_details);
+  grpc_slice_unref_internal(exec_ctx, glb_policy->lb_call_status_details);
 }
 
 /*
@@ -1196,8 +1199,6 @@ static void query_for_backends_locked(grpc_exec_ctx *exec_ctx,
   op->data.recv_status_on_client.status = &glb_policy->lb_call_status;
   op->data.recv_status_on_client.status_details =
       &glb_policy->lb_call_status_details;
-  op->data.recv_status_on_client.status_details_capacity =
-      &glb_policy->lb_call_status_details_capacity;
   op->flags = 0;
   op->reserved = NULL;
   op++;
@@ -1340,15 +1341,18 @@ static void lb_on_server_status_received(grpc_exec_ctx *exec_ctx, void *arg,
   GPR_ASSERT(glb_policy->lb_call != NULL);
 
   if (grpc_lb_glb_trace) {
+    char *status_details =
+        grpc_slice_to_c_string(glb_policy->lb_call_status_details);
     gpr_log(GPR_DEBUG,
             "Status from LB server received. Status = %d, Details = '%s', "
             "(call: %p)",
-            glb_policy->lb_call_status, glb_policy->lb_call_status_details,
+            glb_policy->lb_call_status, status_details,
             (void *)glb_policy->lb_call);
+    gpr_free(status_details);
   }
 
-  /* We need to performe cleanups no matter what. */
-  lb_call_destroy_locked(glb_policy);
+  /* We need to perform cleanups no matter what. */
+  lb_call_destroy_locked(exec_ctx, glb_policy);
 
   if (!glb_policy->shutting_down) {
     /* if we aren't shutting down, restart the LB client call after some time */

src/core/ext/load_reporting/load_reporting_filter.c

@@ -41,13 +41,17 @@
 #include "src/core/ext/load_reporting/load_reporting_filter.h"
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/profiling/timers.h"
+#include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/transport/static_metadata.h"
 
 typedef struct call_data {
   intptr_t id; /**< an id unique to the call */
-  char *trailing_md_string;
-  char *initial_md_string;
-  const char *service_method;
+  bool have_trailing_md_string;
+  grpc_slice trailing_md_string;
+  bool have_initial_md_string;
+  grpc_slice initial_md_string;
+  bool have_service_method;
+  grpc_slice service_method;
 
   /* stores the recv_initial_metadata op's ready closure, which we wrap with our
    * own (on_initial_md_ready) in order to capture the incoming initial metadata
@@ -63,42 +67,28 @@ typedef struct channel_data {
   intptr_t id; /**< an id unique to the channel */
 } channel_data;
 
-typedef struct {
-  grpc_call_element *elem;
-  grpc_exec_ctx *exec_ctx;
-} recv_md_filter_args;
-
-static grpc_mdelem *recv_md_filter(grpc_exec_ctx *exec_ctx, void *user_data,
-                                   grpc_mdelem *md) {
-  recv_md_filter_args *a = user_data;
-  grpc_call_element *elem = a->elem;
-  call_data *calld = elem->call_data;
-
-  if (md->key == GRPC_MDSTR_PATH) {
-    calld->service_method = grpc_mdstr_as_c_string(md->value);
-  } else if (md->key == GRPC_MDSTR_LB_TOKEN) {
-    calld->initial_md_string = gpr_strdup(grpc_mdstr_as_c_string(md->value));
-    return NULL;
-  }
-
-  return md;
-}
-
 static void on_initial_md_ready(grpc_exec_ctx *exec_ctx, void *user_data,
                                 grpc_error *err) {
   grpc_call_element *elem = user_data;
   call_data *calld = elem->call_data;
 
   if (err == GRPC_ERROR_NONE) {
-    recv_md_filter_args a;
-    a.elem = elem;
-    a.exec_ctx = exec_ctx;
-    grpc_metadata_batch_filter(exec_ctx, calld->recv_initial_metadata,
-                               recv_md_filter, &a);
-    if (calld->service_method == NULL) {
+    if (calld->recv_initial_metadata->idx.named.path != NULL) {
+      calld->service_method = grpc_slice_ref_internal(
+          GRPC_MDVALUE(calld->recv_initial_metadata->idx.named.path->md));
+      calld->have_service_method = true;
+    } else {
       err =
           grpc_error_add_child(err, GRPC_ERROR_CREATE("Missing :path header"));
     }
+    if (calld->recv_initial_metadata->idx.named.lb_token != NULL) {
+      calld->initial_md_string = grpc_slice_ref_internal(
+          GRPC_MDVALUE(calld->recv_initial_metadata->idx.named.lb_token->md));
+      calld->have_initial_md_string = true;
+      grpc_metadata_batch_remove(
+          exec_ctx, calld->recv_initial_metadata,
+          calld->recv_initial_metadata->idx.named.lb_token);
+    }
   } else {
     GRPC_ERROR_REF(err);
   }
@@ -149,8 +139,15 @@ static void destroy_call_elem(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
                                                 calld->service_method};
   */
 
-  gpr_free(calld->initial_md_string);
-  gpr_free(calld->trailing_md_string);
+  if (calld->have_initial_md_string) {
+    grpc_slice_unref_internal(exec_ctx, calld->initial_md_string);
+  }
+  if (calld->have_trailing_md_string) {
+    grpc_slice_unref_internal(exec_ctx, calld->trailing_md_string);
+  }
+  if (calld->have_service_method) {
+    grpc_slice_unref_internal(exec_ctx, calld->service_method);
+  }
 }
 
 /* Constructor for channel_data */
@@ -193,19 +190,6 @@ static void destroy_channel_elem(grpc_exec_ctx *exec_ctx,
   */
 }
 
-static grpc_mdelem *lr_trailing_md_filter(grpc_exec_ctx *exec_ctx,
-                                          void *user_data, grpc_mdelem *md) {
-  grpc_call_element *elem = user_data;
-  call_data *calld = elem->call_data;
-
-  if (md->key == GRPC_MDSTR_LB_COST_BIN) {
-    calld->trailing_md_string = gpr_strdup(grpc_mdstr_as_c_string(md->value));
-    return NULL;
-  }
-
-  return md;
-}
-
 static void lr_start_transport_stream_op(grpc_exec_ctx *exec_ctx,
                                          grpc_call_element *elem,
                                          grpc_transport_stream_op *op) {
@@ -218,8 +202,14 @@ static void lr_start_transport_stream_op(grpc_exec_ctx *exec_ctx,
     calld->ops_recv_initial_metadata_ready = op->recv_initial_metadata_ready;
     op->recv_initial_metadata_ready = &calld->on_initial_md_ready;
   } else if (op->send_trailing_metadata) {
-    grpc_metadata_batch_filter(exec_ctx, op->send_trailing_metadata,
-                               lr_trailing_md_filter, elem);
+    if (op->send_trailing_metadata->idx.named.lb_cost_bin != NULL) {
+      calld->trailing_md_string = grpc_slice_ref_internal(
+          GRPC_MDVALUE(op->send_trailing_metadata->idx.named.lb_cost_bin->md));
+      calld->have_trailing_md_string = true;
+      grpc_metadata_batch_remove(
+          exec_ctx, op->send_trailing_metadata,
+          op->send_trailing_metadata->idx.named.lb_cost_bin);
+    }
   }
   grpc_call_next_op(exec_ctx, elem, op);
 

src/core/ext/resolver/dns/native/dns_resolver.c

@@ -188,9 +188,8 @@ static void dns_on_resolved(grpc_exec_ctx *exec_ctx, void *arg,
     gpr_timespec now = gpr_now(GPR_CLOCK_MONOTONIC);
     gpr_timespec next_try = gpr_backoff_step(&r->backoff_state, now);
     gpr_timespec timeout = gpr_time_sub(next_try, now);
-    const char *msg = grpc_error_string(error);
-    gpr_log(GPR_INFO, "dns resolution failed (will retry): %s", msg);
-    grpc_error_free_string(msg);
+    gpr_log(GPR_INFO, "dns resolution failed (will retry): %s",
+            grpc_error_string(error));
     GPR_ASSERT(!r->have_retry_timer);
     r->have_retry_timer = true;
     GRPC_RESOLVER_REF(&r->base, "retry-timer");

src/core/ext/resolver/sockaddr/sockaddr_resolver.c

@@ -182,7 +182,7 @@ static grpc_resolver *sockaddr_create(grpc_exec_ctx *exec_ctx,
   bool errors_found = false;
   for (size_t i = 0; i < addresses->num_addresses; i++) {
     grpc_uri ith_uri = *args->uri;
-    char *part_str = grpc_dump_slice(path_parts.slices[i], GPR_DUMP_ASCII);
+    char *part_str = grpc_slice_to_c_string(path_parts.slices[i]);
     ith_uri.path = part_str;
     if (!parse(&ith_uri, &addresses->addresses[i].address)) {
       errors_found = true; /* GPR_TRUE */

src/core/ext/transport/chttp2/server/chttp2_server.c

@@ -121,7 +121,7 @@ static void on_handshake_done(grpc_exec_ctx *exec_ctx, void *arg,
   if (error != GRPC_ERROR_NONE || connection_state->server_state->shutdown) {
     const char *error_str = grpc_error_string(error);
     gpr_log(GPR_ERROR, "Handshaking failed: %s", error_str);
-    grpc_error_free_string(error_str);
+
     if (error == GRPC_ERROR_NONE && args->endpoint != NULL) {
       // We were shut down after handshaking completed successfully, so
       // destroy the endpoint here.
@@ -307,7 +307,7 @@ grpc_error *grpc_chttp2_server_add_port(grpc_exec_ctx *exec_ctx,
 
     const char *warning_message = grpc_error_string(err);
     gpr_log(GPR_INFO, "WARNING: %s", warning_message);
-    grpc_error_free_string(warning_message);
+
     /* we managed to bind some addresses: continue */
   }
   grpc_resolved_addresses_destroy(resolved);

src/core/ext/transport/chttp2/server/insecure/server_chttp2.c

@@ -51,7 +51,7 @@ int grpc_server_add_insecure_http2_port(grpc_server *server, const char *addr) {
   if (err != GRPC_ERROR_NONE) {
     const char *msg = grpc_error_string(err);
     gpr_log(GPR_ERROR, "%s", msg);
-    grpc_error_free_string(msg);
+
     GRPC_ERROR_UNREF(err);
   }
   grpc_exec_ctx_finish(&exec_ctx);

src/core/ext/transport/chttp2/server/secure/server_secure_chttp2.c

@@ -94,7 +94,7 @@ done:
   if (err != GRPC_ERROR_NONE) {
     const char *msg = grpc_error_string(err);
     gpr_log(GPR_ERROR, "%s", msg);
-    grpc_error_free_string(msg);
+
     GRPC_ERROR_UNREF(err);
   }
   return port_num;

src/core/ext/transport/chttp2/transport/bin_decoder.c

@@ -157,7 +157,7 @@ grpc_slice grpc_chttp2_base64_decode(grpc_exec_ctx *exec_ctx,
             "grpc_chttp2_base64_decode has a length of %d, which is not a "
             "multiple of 4.\n",
             (int)input_length);
-    return gpr_empty_slice();
+    return grpc_empty_slice();
   }
 
   if (input_length > 0) {
@@ -178,11 +178,11 @@ grpc_slice grpc_chttp2_base64_decode(grpc_exec_ctx *exec_ctx,
   ctx.contains_tail = false;
 
   if (!grpc_base64_decode_partial(&ctx)) {
-    char *s = grpc_dump_slice(input, GPR_DUMP_ASCII);
+    char *s = grpc_slice_to_c_string(input);
     gpr_log(GPR_ERROR, "Base64 decoding failed, input string:\n%s\n", s);
     gpr_free(s);
     grpc_slice_unref_internal(exec_ctx, output);
-    return gpr_empty_slice();
+    return grpc_empty_slice();
   }
   GPR_ASSERT(ctx.output_cur == GRPC_SLICE_END_PTR(output));
   GPR_ASSERT(ctx.input_cur == GRPC_SLICE_END_PTR(input));
@@ -204,7 +204,7 @@ grpc_slice grpc_chttp2_base64_decode_with_length(grpc_exec_ctx *exec_ctx,
             "has a tail of 1 byte.\n",
             (int)input_length);
     grpc_slice_unref_internal(exec_ctx, output);
-    return gpr_empty_slice();
+    return grpc_empty_slice();
   }
 
   if (output_length > input_length / 4 * 3 + tail_xtra[input_length % 4]) {
@@ -214,7 +214,7 @@ grpc_slice grpc_chttp2_base64_decode_with_length(grpc_exec_ctx *exec_ctx,
             (int)output_length,
             (int)(input_length / 4 * 3 + tail_xtra[input_length % 4]));
     grpc_slice_unref_internal(exec_ctx, output);
-    return gpr_empty_slice();
+    return grpc_empty_slice();
   }
 
   ctx.input_cur = GRPC_SLICE_START_PTR(input);
@@ -224,11 +224,11 @@ grpc_slice grpc_chttp2_base64_decode_with_length(grpc_exec_ctx *exec_ctx,
   ctx.contains_tail = true;
 
   if (!grpc_base64_decode_partial(&ctx)) {
-    char *s = grpc_dump_slice(input, GPR_DUMP_ASCII);
+    char *s = grpc_slice_to_c_string(input);
     gpr_log(GPR_ERROR, "Base64 decoding failed, input string:\n%s\n", s);
     gpr_free(s);
     grpc_slice_unref_internal(exec_ctx, output);
-    return gpr_empty_slice();
+    return grpc_empty_slice();
   }
   GPR_ASSERT(ctx.output_cur == GRPC_SLICE_END_PTR(output));
   GPR_ASSERT(ctx.input_cur <= GRPC_SLICE_END_PTR(input));

src/core/ext/transport/chttp2/transport/bin_encoder.c

@@ -177,8 +177,7 @@ static void enc_add1(huff_out *out, uint8_t a) {
   enc_flush_some(out);
 }
 
-grpc_slice grpc_chttp2_base64_encode_and_huffman_compress_impl(
-    grpc_slice input) {
+grpc_slice grpc_chttp2_base64_encode_and_huffman_compress(grpc_slice input) {
   size_t input_length = GRPC_SLICE_LENGTH(input);
   size_t input_triplets = input_length / 3;
   size_t tail_case = input_length % 3;

src/core/ext/transport/chttp2/transport/bin_encoder.h

@@ -49,7 +49,6 @@ grpc_slice grpc_chttp2_huffman_compress(grpc_slice input);
    grpc_slice y = grpc_chttp2_huffman_compress(x);
    grpc_slice_unref_internal(exec_ctx, x);
    return y; */
-grpc_slice grpc_chttp2_base64_encode_and_huffman_compress_impl(
-    grpc_slice input);
+grpc_slice grpc_chttp2_base64_encode_and_huffman_compress(grpc_slice input);
 
 #endif /* GRPC_CORE_EXT_TRANSPORT_CHTTP2_TRANSPORT_BIN_ENCODER_H */

src/core/ext/transport/chttp2/transport/chttp2_plugin.c

@@ -31,14 +31,11 @@
  *
  */
 
-#include "src/core/ext/transport/chttp2/transport/bin_encoder.h"
 #include "src/core/ext/transport/chttp2/transport/chttp2_transport.h"
 #include "src/core/lib/debug/trace.h"
 #include "src/core/lib/transport/metadata.h"
 
 void grpc_chttp2_plugin_init(void) {
-  grpc_chttp2_base64_encode_and_huffman_compress =
-      grpc_chttp2_base64_encode_and_huffman_compress_impl;
   grpc_register_tracer("http", &grpc_http_trace);
   grpc_register_tracer("flowctl", &grpc_flowctl_trace);
 }

src/core/ext/transport/chttp2/transport/chttp2_transport.c

@@ -44,9 +44,7 @@
 #include <grpc/support/string_util.h>
 #include <grpc/support/useful.h>
 
-#include "src/core/ext/transport/chttp2/transport/http2_errors.h"
 #include "src/core/ext/transport/chttp2/transport/internal.h"
-#include "src/core/ext/transport/chttp2/transport/status_conversion.h"
 #include "src/core/ext/transport/chttp2/transport/varint.h"
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/http/parser.h"
@@ -55,7 +53,10 @@
 #include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/slice/slice_string_helpers.h"
 #include "src/core/lib/support/string.h"
+#include "src/core/lib/transport/error_utils.h"
+#include "src/core/lib/transport/http2_errors.h"
 #include "src/core/lib/transport/static_metadata.h"
+#include "src/core/lib/transport/status_conversion.h"
 #include "src/core/lib/transport/timeout_encoding.h"
 #include "src/core/lib/transport/transport_impl.h"
 
@@ -409,7 +410,7 @@ static void close_transport_locked(grpc_exec_ctx *exec_ctx,
           grpc_error_add_child(t->close_transport_on_writes_finished, error);
       return;
     }
-    if (!grpc_error_get_int(error, GRPC_ERROR_INT_GRPC_STATUS, NULL)) {
+    if (!grpc_error_has_clear_grpc_status(error)) {
       error = grpc_error_set_int(error, GRPC_ERROR_INT_GRPC_STATUS,
                                  GRPC_STATUS_UNAVAILABLE);
     }
@@ -866,7 +867,6 @@ void grpc_chttp2_complete_closure_step(grpc_exec_ctx *exec_ctx,
             (int)(closure->next_data.scratch / CLOSURE_BARRIER_FIRST_REF_BIT),
             (int)(closure->next_data.scratch % CLOSURE_BARRIER_FIRST_REF_BIT),
             desc, errstr);
-    grpc_error_free_string(errstr);
   }
   if (error != GRPC_ERROR_NONE) {
     if (closure->error_data.error == GRPC_ERROR_NONE) {
@@ -895,12 +895,9 @@ void grpc_chttp2_complete_closure_step(grpc_exec_ctx *exec_ctx,
 }
 
 static bool contains_non_ok_status(grpc_metadata_batch *batch) {
-  grpc_linked_mdelem *l;
-  for (l = batch->list.head; l; l = l->next) {
-    if (l->md->key == GRPC_MDSTR_GRPC_STATUS &&
-        l->md != GRPC_MDELEM_GRPC_STATUS_0) {
-      return true;
-    }
+  if (batch->idx.named.grpc_status != NULL) {
+    return !grpc_mdelem_eq(batch->idx.named.grpc_status->md,
+                           GRPC_MDELEM_GRPC_STATUS_0);
   }
   return false;
 }
@@ -980,9 +977,12 @@ static void log_metadata(const grpc_metadata_batch *md_batch, uint32_t id,
                          bool is_client, bool is_initial) {
   for (grpc_linked_mdelem *md = md_batch->list.head; md != md_batch->list.tail;
        md = md->next) {
+    char *key = grpc_slice_to_c_string(GRPC_MDKEY(md->md));
+    char *value = grpc_slice_to_c_string(GRPC_MDVALUE(md->md));
     gpr_log(GPR_INFO, "HTTP:%d:%s:%s: %s: %s", id, is_initial ? "HDR" : "TRL",
-            is_client ? "CLI" : "SVR", grpc_mdstr_as_c_string(md->md->key),
-            grpc_mdstr_as_c_string(md->md->value));
+            is_client ? "CLI" : "SVR", key, value);
+    gpr_free(key);
+    gpr_free(value);
   }
 }
 
@@ -1025,11 +1025,7 @@ static void perform_stream_op_locked(grpc_exec_ctx *exec_ctx, void *stream_op,
   }
 
   if (op->cancel_error != GRPC_ERROR_NONE) {
-    grpc_chttp2_cancel_stream(exec_ctx, t, s, GRPC_ERROR_REF(op->cancel_error));
-  }
-
-  if (op->close_error != GRPC_ERROR_NONE) {
-    close_from_api(exec_ctx, t, s, GRPC_ERROR_REF(op->close_error));
+    grpc_chttp2_cancel_stream(exec_ctx, t, s, op->cancel_error);
   }
 
   if (op->send_initial_metadata != NULL) {
@@ -1080,8 +1076,9 @@ static void perform_stream_op_locked(grpc_exec_ctx *exec_ctx, void *stream_op,
         s->send_initial_metadata = NULL;
         grpc_chttp2_complete_closure_step(
             exec_ctx, t, s, &s->send_initial_metadata_finished,
-            GRPC_ERROR_CREATE(
-                "Attempt to send initial metadata after stream was closed"),
+            GRPC_ERROR_CREATE_REFERENCING(
+                "Attempt to send initial metadata after stream was closed",
+                &s->write_closed_error, 1),
             "send_initial_metadata_finished");
       }
     }
@@ -1093,7 +1090,9 @@ static void perform_stream_op_locked(grpc_exec_ctx *exec_ctx, void *stream_op,
     if (s->write_closed) {
       grpc_chttp2_complete_closure_step(
           exec_ctx, t, s, &s->fetching_send_message_finished,
-          GRPC_ERROR_CREATE("Attempt to send message after stream was closed"),
+          GRPC_ERROR_CREATE_REFERENCING(
+              "Attempt to send message after stream was closed",
+              &s->write_closed_error, 1),
           "fetching_send_message_finished");
     } else {
       GPR_ASSERT(s->fetching_send_message == NULL);
@@ -1265,11 +1264,16 @@ void grpc_chttp2_ack_ping(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
 }
 
 static void send_goaway(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
-                        grpc_chttp2_error_code error, grpc_slice data) {
+                        grpc_error *error) {
   t->sent_goaway_state = GRPC_CHTTP2_GOAWAY_SEND_SCHEDULED;
-  grpc_chttp2_goaway_append(t->last_new_stream_id, (uint32_t)error, data,
-                            &t->qbuf);
+  grpc_http2_error_code http_error;
+  const char *msg;
+  grpc_error_get_status(error, gpr_inf_future(GPR_CLOCK_MONOTONIC), NULL, &msg,
+                        &http_error);
+  grpc_chttp2_goaway_append(t->last_new_stream_id, (uint32_t)http_error,
+                            grpc_slice_from_copied_string(msg), &t->qbuf);
   grpc_chttp2_initiate_write(exec_ctx, t, false, "goaway_sent");
+  GRPC_ERROR_UNREF(error);
 }
 
 static void perform_transport_op_locked(grpc_exec_ctx *exec_ctx,
@@ -1285,10 +1289,8 @@ static void perform_transport_op_locked(grpc_exec_ctx *exec_ctx,
         op->on_connectivity_state_change);
   }
 
-  if (op->send_goaway) {
-    send_goaway(exec_ctx, t,
-                grpc_chttp2_grpc_status_to_http2_error(op->goaway_status),
-                grpc_slice_ref_internal(*op->goaway_message));
+  if (op->goaway_error) {
+    send_goaway(exec_ctx, t, op->goaway_error);
   }
 
   if (op->set_accept_stream) {
@@ -1348,8 +1350,8 @@ void grpc_chttp2_maybe_complete_recv_initial_metadata(grpc_exec_ctx *exec_ctx,
         incoming_byte_stream_destroy_locked(exec_ctx, bs, GRPC_ERROR_NONE);
       }
     }
-    grpc_chttp2_incoming_metadata_buffer_publish(&s->metadata_buffer[0],
-                                                 s->recv_initial_metadata);
+    grpc_chttp2_incoming_metadata_buffer_publish(
+        exec_ctx, &s->metadata_buffer[0], s->recv_initial_metadata);
     null_then_run_closure(exec_ctx, &s->recv_initial_metadata_ready,
                           GRPC_ERROR_NONE);
   }
@@ -1392,8 +1394,8 @@ void grpc_chttp2_maybe_complete_recv_trailing_metadata(grpc_exec_ctx *exec_ctx,
     }
     if (s->all_incoming_byte_streams_finished &&
         s->recv_trailing_metadata_finished != NULL) {
-      grpc_chttp2_incoming_metadata_buffer_publish(&s->metadata_buffer[1],
-                                                   s->recv_trailing_metadata);
+      grpc_chttp2_incoming_metadata_buffer_publish(
+          exec_ctx, &s->metadata_buffer[1], s->recv_trailing_metadata);
       grpc_chttp2_complete_closure_step(
           exec_ctx, t, s, &s->recv_trailing_metadata_finished, GRPC_ERROR_NONE,
           "recv_trailing_metadata_finished");
@@ -1441,70 +1443,37 @@ static void remove_stream(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
   maybe_start_some_streams(exec_ctx, t);
 }
 
-static void status_codes_from_error(grpc_error *error, gpr_timespec deadline,
-                                    grpc_chttp2_error_code *http2_error,
-                                    grpc_status_code *grpc_status) {
-  intptr_t ip_http;
-  intptr_t ip_grpc;
-  bool have_http =
-      grpc_error_get_int(error, GRPC_ERROR_INT_HTTP2_ERROR, &ip_http);
-  bool have_grpc =
-      grpc_error_get_int(error, GRPC_ERROR_INT_GRPC_STATUS, &ip_grpc);
-  if (have_http) {
-    *http2_error = (grpc_chttp2_error_code)ip_http;
-  } else if (have_grpc) {
-    *http2_error =
-        grpc_chttp2_grpc_status_to_http2_error((grpc_status_code)ip_grpc);
-  } else {
-    *http2_error = GRPC_CHTTP2_INTERNAL_ERROR;
-  }
-  if (have_grpc) {
-    *grpc_status = (grpc_status_code)ip_grpc;
-  } else if (have_http) {
-    *grpc_status = grpc_chttp2_http2_error_to_grpc_status(
-        (grpc_chttp2_error_code)ip_http, deadline);
-  } else {
-    *grpc_status = GRPC_STATUS_INTERNAL;
-  }
-}
-
 void grpc_chttp2_cancel_stream(grpc_exec_ctx *exec_ctx,
                                grpc_chttp2_transport *t, grpc_chttp2_stream *s,
                                grpc_error *due_to_error) {
-  if (!s->read_closed || !s->write_closed) {
-    grpc_status_code grpc_status;
-    grpc_chttp2_error_code http_error;
-    status_codes_from_error(due_to_error, s->deadline, &http_error,
-                            &grpc_status);
+  if (!t->is_client && !s->sent_trailing_metadata &&
+      grpc_error_has_clear_grpc_status(due_to_error)) {
+    close_from_api(exec_ctx, t, s, due_to_error);
+    return;
+  }
 
+  if (!s->read_closed || !s->write_closed) {
     if (s->id != 0) {
+      grpc_http2_error_code http_error;
+      grpc_error_get_status(due_to_error, s->deadline, NULL, NULL, &http_error);
       grpc_slice_buffer_add(
           &t->qbuf, grpc_chttp2_rst_stream_create(s->id, (uint32_t)http_error,
                                                   &s->stats.outgoing));
       grpc_chttp2_initiate_write(exec_ctx, t, false, "rst_stream");
     }
-
-    const char *msg =
-        grpc_error_get_str(due_to_error, GRPC_ERROR_STR_GRPC_MESSAGE);
-    bool free_msg = false;
-    if (msg == NULL) {
-      free_msg = true;
-      msg = grpc_error_string(due_to_error);
-    }
-    grpc_slice msg_slice = grpc_slice_from_copied_string(msg);
-    grpc_chttp2_fake_status(exec_ctx, t, s, grpc_status, &msg_slice);
-    if (free_msg) grpc_error_free_string(msg);
   }
   if (due_to_error != GRPC_ERROR_NONE && !s->seen_error) {
     s->seen_error = true;
-    grpc_chttp2_maybe_complete_recv_trailing_metadata(exec_ctx, t, s);
   }
   grpc_chttp2_mark_stream_closed(exec_ctx, t, s, 1, 1, due_to_error);
 }
 
 void grpc_chttp2_fake_status(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
-                             grpc_chttp2_stream *s, grpc_status_code status,
-                             grpc_slice *slice) {
+                             grpc_chttp2_stream *s, grpc_error *error) {
+  grpc_status_code status;
+  const char *msg;
+  grpc_error_get_status(error, s->deadline, &status, &msg, NULL);
+
   if (status != GRPC_STATUS_OK) {
     s->seen_error = true;
   }
@@ -1518,24 +1487,21 @@ void grpc_chttp2_fake_status(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
       s->recv_trailing_metadata_finished != NULL) {
     char status_string[GPR_LTOA_MIN_BUFSIZE];
     gpr_ltoa(status, status_string);
-    grpc_chttp2_incoming_metadata_buffer_add(
-        &s->metadata_buffer[1], grpc_mdelem_from_metadata_strings(
-                                    exec_ctx, GRPC_MDSTR_GRPC_STATUS,
-                                    grpc_mdstr_from_string(status_string)));
-    if (slice) {
-      grpc_chttp2_incoming_metadata_buffer_add(
-          &s->metadata_buffer[1],
-          grpc_mdelem_from_metadata_strings(
-              exec_ctx, GRPC_MDSTR_GRPC_MESSAGE,
-              grpc_mdstr_from_slice(exec_ctx,
-                                    grpc_slice_ref_internal(*slice))));
+    grpc_chttp2_incoming_metadata_buffer_replace_or_add(
+        exec_ctx, &s->metadata_buffer[1],
+        grpc_mdelem_from_slices(exec_ctx, GRPC_MDSTR_GRPC_STATUS,
+                                grpc_slice_from_copied_string(status_string)));
+    if (msg != NULL) {
+      grpc_chttp2_incoming_metadata_buffer_replace_or_add(
+          exec_ctx, &s->metadata_buffer[1],
+          grpc_mdelem_from_slices(exec_ctx, GRPC_MDSTR_GRPC_MESSAGE,
+                                  grpc_slice_from_copied_string(msg)));
     }
     s->published_metadata[1] = GRPC_METADATA_SYNTHESIZED_FROM_FAKE;
     grpc_chttp2_maybe_complete_recv_trailing_metadata(exec_ctx, t, s);
   }
-  if (slice) {
-    grpc_slice_unref_internal(exec_ctx, *slice);
-  }
+
+  GRPC_ERROR_UNREF(error);
 }
 
 static void add_error(grpc_error *error, grpc_error **refs, size_t *nrefs) {
@@ -1601,36 +1567,48 @@ void grpc_chttp2_mark_stream_closed(grpc_exec_ctx *exec_ctx,
                                     int close_writes, grpc_error *error) {
   if (s->read_closed && s->write_closed) {
     /* already closed */
+    grpc_chttp2_maybe_complete_recv_trailing_metadata(exec_ctx, t, s);
     GRPC_ERROR_UNREF(error);
     return;
   }
+  bool closed_read = false;
+  bool became_closed = false;
   if (close_reads && !s->read_closed) {
     s->read_closed_error = GRPC_ERROR_REF(error);
     s->read_closed = true;
-    for (int i = 0; i < 2; i++) {
-      if (s->published_metadata[i] == GRPC_METADATA_NOT_PUBLISHED) {
-        s->published_metadata[i] = GPRC_METADATA_PUBLISHED_AT_CLOSE;
-      }
-    }
-    decrement_active_streams_locked(exec_ctx, t, s);
-    grpc_chttp2_maybe_complete_recv_initial_metadata(exec_ctx, t, s);
-    grpc_chttp2_maybe_complete_recv_message(exec_ctx, t, s);
-    grpc_chttp2_maybe_complete_recv_trailing_metadata(exec_ctx, t, s);
+    closed_read = true;
   }
   if (close_writes && !s->write_closed) {
     s->write_closed_error = GRPC_ERROR_REF(error);
     s->write_closed = true;
     grpc_chttp2_fail_pending_writes(exec_ctx, t, s, GRPC_ERROR_REF(error));
-    grpc_chttp2_maybe_complete_recv_trailing_metadata(exec_ctx, t, s);
   }
   if (s->read_closed && s->write_closed) {
+    became_closed = true;
+    grpc_error *overall_error =
+        removal_error(GRPC_ERROR_REF(error), s, "Stream removed");
     if (s->id != 0) {
-      remove_stream(exec_ctx, t, s->id,
-                    removal_error(GRPC_ERROR_REF(error), s, "Stream removed"));
+      remove_stream(exec_ctx, t, s->id, GRPC_ERROR_REF(overall_error));
     } else {
       /* Purge streams waiting on concurrency still waiting for id assignment */
       grpc_chttp2_list_remove_waiting_for_concurrency(t, s);
     }
+    if (overall_error != GRPC_ERROR_NONE) {
+      grpc_chttp2_fake_status(exec_ctx, t, s, overall_error);
+    }
+  }
+  if (closed_read) {
+    for (int i = 0; i < 2; i++) {
+      if (s->published_metadata[i] == GRPC_METADATA_NOT_PUBLISHED) {
+        s->published_metadata[i] = GPRC_METADATA_PUBLISHED_AT_CLOSE;
+      }
+    }
+    decrement_active_streams_locked(exec_ctx, t, s);
+    grpc_chttp2_maybe_complete_recv_initial_metadata(exec_ctx, t, s);
+    grpc_chttp2_maybe_complete_recv_message(exec_ctx, t, s);
+  }
+  if (became_closed) {
+    grpc_chttp2_maybe_complete_recv_trailing_metadata(exec_ctx, t, s);
     GRPC_CHTTP2_STREAM_UNREF(exec_ctx, s, "chttp2");
   }
   GRPC_ERROR_UNREF(error);
@@ -1644,112 +1622,92 @@ static void close_from_api(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
   uint8_t *p;
   uint32_t len = 0;
   grpc_status_code grpc_status;
-  grpc_chttp2_error_code http_error;
-  status_codes_from_error(error, s->deadline, &http_error, &grpc_status);
+  const char *msg;
+  grpc_error_get_status(error, s->deadline, &grpc_status, &msg, NULL);
 
   GPR_ASSERT(grpc_status >= 0 && (int)grpc_status < 100);
 
-  if (s->id != 0 && !t->is_client) {
-    /* Hand roll a header block.
-       This is unnecessarily ugly - at some point we should find a more
-       elegant
-       solution.
-       It's complicated by the fact that our send machinery would be dead by
-       the
-       time we got around to sending this, so instead we ignore HPACK
-       compression
-       and just write the uncompressed bytes onto the wire. */
-    status_hdr = grpc_slice_malloc(15 + (grpc_status >= 10));
-    p = GRPC_SLICE_START_PTR(status_hdr);
-    *p++ = 0x40; /* literal header */
-    *p++ = 11;   /* len(grpc-status) */
+  /* Hand roll a header block.
+     This is unnecessarily ugly - at some point we should find a more
+     elegant solution.
+     It's complicated by the fact that our send machinery would be dead by
+     the time we got around to sending this, so instead we ignore HPACK
+     compression and just write the uncompressed bytes onto the wire. */
+  status_hdr = grpc_slice_malloc(15 + (grpc_status >= 10));
+  p = GRPC_SLICE_START_PTR(status_hdr);
+  *p++ = 0x00; /* literal header, not indexed */
+  *p++ = 11;   /* len(grpc-status) */
+  *p++ = 'g';
+  *p++ = 'r';
+  *p++ = 'p';
+  *p++ = 'c';
+  *p++ = '-';
+  *p++ = 's';
+  *p++ = 't';
+  *p++ = 'a';
+  *p++ = 't';
+  *p++ = 'u';
+  *p++ = 's';
+  if (grpc_status < 10) {
+    *p++ = 1;
+    *p++ = (uint8_t)('0' + grpc_status);
+  } else {
+    *p++ = 2;
+    *p++ = (uint8_t)('0' + (grpc_status / 10));
+    *p++ = (uint8_t)('0' + (grpc_status % 10));
+  }
+  GPR_ASSERT(p == GRPC_SLICE_END_PTR(status_hdr));
+  len += (uint32_t)GRPC_SLICE_LENGTH(status_hdr);
+
+  if (msg != NULL) {
+    size_t msg_len = strlen(msg);
+    GPR_ASSERT(msg_len <= UINT32_MAX);
+    uint32_t msg_len_len = GRPC_CHTTP2_VARINT_LENGTH((uint32_t)msg_len, 0);
+    message_pfx = grpc_slice_malloc(14 + msg_len_len);
+    p = GRPC_SLICE_START_PTR(message_pfx);
+    *p++ = 0x00; /* literal header, not indexed */
+    *p++ = 12;   /* len(grpc-message) */
     *p++ = 'g';
     *p++ = 'r';
     *p++ = 'p';
     *p++ = 'c';
     *p++ = '-';
+    *p++ = 'm';
+    *p++ = 'e';
     *p++ = 's';
-    *p++ = 't';
-    *p++ = 'a';
-    *p++ = 't';
-    *p++ = 'u';
     *p++ = 's';
-    if (grpc_status < 10) {
-      *p++ = 1;
-      *p++ = (uint8_t)('0' + grpc_status);
-    } else {
-      *p++ = 2;
-      *p++ = (uint8_t)('0' + (grpc_status / 10));
-      *p++ = (uint8_t)('0' + (grpc_status % 10));
-    }
-    GPR_ASSERT(p == GRPC_SLICE_END_PTR(status_hdr));
-    len += (uint32_t)GRPC_SLICE_LENGTH(status_hdr);
-
-    const char *optional_message =
-        grpc_error_get_str(error, GRPC_ERROR_STR_GRPC_MESSAGE);
-
-    if (optional_message != NULL) {
-      size_t msg_len = strlen(optional_message);
-      GPR_ASSERT(msg_len <= UINT32_MAX);
-      uint32_t msg_len_len = GRPC_CHTTP2_VARINT_LENGTH((uint32_t)msg_len, 0);
-      message_pfx = grpc_slice_malloc(14 + msg_len_len);
-      p = GRPC_SLICE_START_PTR(message_pfx);
-      *p++ = 0x40;
-      *p++ = 12; /* len(grpc-message) */
-      *p++ = 'g';
-      *p++ = 'r';
-      *p++ = 'p';
-      *p++ = 'c';
-      *p++ = '-';
-      *p++ = 'm';
-      *p++ = 'e';
-      *p++ = 's';
-      *p++ = 's';
-      *p++ = 'a';
-      *p++ = 'g';
-      *p++ = 'e';
-      GRPC_CHTTP2_WRITE_VARINT((uint32_t)msg_len, 0, 0, p,
-                               (uint32_t)msg_len_len);
-      p += msg_len_len;
-      GPR_ASSERT(p == GRPC_SLICE_END_PTR(message_pfx));
-      len += (uint32_t)GRPC_SLICE_LENGTH(message_pfx);
-      len += (uint32_t)msg_len;
-    }
-
-    hdr = grpc_slice_malloc(9);
-    p = GRPC_SLICE_START_PTR(hdr);
-    *p++ = (uint8_t)(len >> 16);
-    *p++ = (uint8_t)(len >> 8);
-    *p++ = (uint8_t)(len);
-    *p++ = GRPC_CHTTP2_FRAME_HEADER;
-    *p++ = GRPC_CHTTP2_DATA_FLAG_END_STREAM | GRPC_CHTTP2_DATA_FLAG_END_HEADERS;
-    *p++ = (uint8_t)(s->id >> 24);
-    *p++ = (uint8_t)(s->id >> 16);
-    *p++ = (uint8_t)(s->id >> 8);
-    *p++ = (uint8_t)(s->id);
-    GPR_ASSERT(p == GRPC_SLICE_END_PTR(hdr));
-
-    grpc_slice_buffer_add(&t->qbuf, hdr);
-    grpc_slice_buffer_add(&t->qbuf, status_hdr);
-    if (optional_message) {
-      grpc_slice_buffer_add(&t->qbuf, message_pfx);
-      grpc_slice_buffer_add(&t->qbuf,
-                            grpc_slice_from_copied_string(optional_message));
-    }
-    grpc_slice_buffer_add(
-        &t->qbuf, grpc_chttp2_rst_stream_create(s->id, GRPC_CHTTP2_NO_ERROR,
-                                                &s->stats.outgoing));
-  }
-
-  const char *msg = grpc_error_get_str(error, GRPC_ERROR_STR_GRPC_MESSAGE);
-  bool free_msg = false;
-  if (msg == NULL) {
-    free_msg = true;
-    msg = grpc_error_string(error);
-  }
-  grpc_slice msg_slice = grpc_slice_from_copied_string(msg);
-  grpc_chttp2_fake_status(exec_ctx, t, s, grpc_status, &msg_slice);
-  if (free_msg) grpc_error_free_string(msg);
+    *p++ = 'a';
+    *p++ = 'g';
+    *p++ = 'e';
+    GRPC_CHTTP2_WRITE_VARINT((uint32_t)msg_len, 0, 0, p, (uint32_t)msg_len_len);
+    p += msg_len_len;
+    GPR_ASSERT(p == GRPC_SLICE_END_PTR(message_pfx));
+    len += (uint32_t)GRPC_SLICE_LENGTH(message_pfx);
+    len += (uint32_t)msg_len;
+  }
+
+  hdr = grpc_slice_malloc(9);
+  p = GRPC_SLICE_START_PTR(hdr);
+  *p++ = (uint8_t)(len >> 16);
+  *p++ = (uint8_t)(len >> 8);
+  *p++ = (uint8_t)(len);
+  *p++ = GRPC_CHTTP2_FRAME_HEADER;
+  *p++ = GRPC_CHTTP2_DATA_FLAG_END_STREAM | GRPC_CHTTP2_DATA_FLAG_END_HEADERS;
+  *p++ = (uint8_t)(s->id >> 24);
+  *p++ = (uint8_t)(s->id >> 16);
+  *p++ = (uint8_t)(s->id >> 8);
+  *p++ = (uint8_t)(s->id);
+  GPR_ASSERT(p == GRPC_SLICE_END_PTR(hdr));
+
+  grpc_slice_buffer_add(&t->qbuf, hdr);
+  grpc_slice_buffer_add(&t->qbuf, status_hdr);
+  if (msg != NULL) {
+    grpc_slice_buffer_add(&t->qbuf, message_pfx);
+    grpc_slice_buffer_add(&t->qbuf, grpc_slice_from_copied_string(msg));
+  }
+  grpc_slice_buffer_add(
+      &t->qbuf, grpc_chttp2_rst_stream_create(s->id, GRPC_HTTP2_NO_ERROR,
+                                              &s->stats.outgoing));
 
   grpc_chttp2_mark_stream_closed(exec_ctx, t, s, 1, 1, error);
   grpc_chttp2_initiate_write(exec_ctx, t, false, "close_from_api");
@@ -1827,8 +1785,10 @@ static grpc_error *try_http_parsing(grpc_exec_ctx *exec_ctx,
   if (parse_error == GRPC_ERROR_NONE &&
       (parse_error = grpc_http_parser_eof(&parser)) == GRPC_ERROR_NONE) {
     error = grpc_error_set_int(
-        GRPC_ERROR_CREATE("Trying to connect an http1.x server"),
-        GRPC_ERROR_INT_HTTP_STATUS, response.status);
+        grpc_error_set_int(
+            GRPC_ERROR_CREATE("Trying to connect an http1.x server"),
+            GRPC_ERROR_INT_HTTP_STATUS, response.status),
+        GRPC_ERROR_INT_GRPC_STATUS, GRPC_STATUS_UNAVAILABLE);
   }
   GRPC_ERROR_UNREF(parse_error);
 
@@ -2089,6 +2049,8 @@ static void incoming_byte_stream_publish_error(
   grpc_closure_sched(exec_ctx, bs->on_next, GRPC_ERROR_REF(error));
   bs->on_next = NULL;
   GRPC_ERROR_UNREF(bs->error);
+  grpc_chttp2_cancel_stream(exec_ctx, bs->transport, bs->stream,
+                            GRPC_ERROR_REF(error));
   bs->error = error;
 }
 
@@ -2197,8 +2159,10 @@ static void benign_reclaimer_locked(grpc_exec_ctx *exec_ctx, void *arg,
       gpr_log(GPR_DEBUG, "HTTP2: %s - send goaway to free memory",
               t->peer_string);
     }
-    send_goaway(exec_ctx, t, GRPC_CHTTP2_ENHANCE_YOUR_CALM,
-                grpc_slice_from_static_string("Buffers full"));
+    send_goaway(exec_ctx, t,
+                grpc_error_set_int(GRPC_ERROR_CREATE("Buffers full"),
+                                   GRPC_ERROR_INT_HTTP2_ERROR,
+                                   GRPC_HTTP2_ENHANCE_YOUR_CALM));
   } else if (error == GRPC_ERROR_NONE && grpc_resource_quota_trace) {
     gpr_log(GPR_DEBUG,
             "HTTP2: %s - skip benign reclamation, there are still %" PRIdPTR
@@ -2227,7 +2191,7 @@ static void destructive_reclaimer_locked(grpc_exec_ctx *exec_ctx, void *arg,
     grpc_chttp2_cancel_stream(
         exec_ctx, t, s, grpc_error_set_int(GRPC_ERROR_CREATE("Buffers full"),
                                            GRPC_ERROR_INT_HTTP2_ERROR,
-                                           GRPC_CHTTP2_ENHANCE_YOUR_CALM));
+                                           GRPC_HTTP2_ENHANCE_YOUR_CALM));
     if (n > 1) {
       /* Since we cancel one stream per destructive reclamation, if
          there are more streams left, we can immediately post a new

src/core/ext/transport/chttp2/transport/frame_rst_stream.c

@@ -39,8 +39,7 @@
 #include <grpc/support/string_util.h>
 
 #include "src/core/ext/transport/chttp2/transport/frame.h"
-#include "src/core/ext/transport/chttp2/transport/http2_errors.h"
-#include "src/core/ext/transport/chttp2/transport/status_conversion.h"
+#include "src/core/lib/transport/http2_errors.h"
 
 grpc_slice grpc_chttp2_rst_stream_create(uint32_t id, uint32_t code,
                                          grpc_transport_one_way_stats *stats) {
@@ -109,17 +108,9 @@ grpc_error *grpc_chttp2_rst_stream_parser_parse(grpc_exec_ctx *exec_ctx,
                       (((uint32_t)p->reason_bytes[2]) << 8) |
                       (((uint32_t)p->reason_bytes[3]));
     grpc_error *error = GRPC_ERROR_NONE;
-    if (reason != GRPC_CHTTP2_NO_ERROR || s->header_frames_received < 2) {
+    if (reason != GRPC_HTTP2_NO_ERROR || s->header_frames_received < 2) {
       error = grpc_error_set_int(GRPC_ERROR_CREATE("RST_STREAM"),
                                  GRPC_ERROR_INT_HTTP2_ERROR, (intptr_t)reason);
-      grpc_status_code status_code = grpc_chttp2_http2_error_to_grpc_status(
-          (grpc_chttp2_error_code)reason, s->deadline);
-      char *status_details;
-      gpr_asprintf(&status_details, "Received RST_STREAM with error code %d",
-                   reason);
-      grpc_slice slice_details = grpc_slice_from_copied_string(status_details);
-      gpr_free(status_details);
-      grpc_chttp2_fake_status(exec_ctx, t, s, status_code, &slice_details);
     }
     grpc_chttp2_mark_stream_closed(exec_ctx, t, s, true, true, error);
   }

src/core/ext/transport/chttp2/transport/frame_settings.c

@@ -43,8 +43,8 @@
 
 #include "src/core/ext/transport/chttp2/transport/chttp2_transport.h"
 #include "src/core/ext/transport/chttp2/transport/frame.h"
-#include "src/core/ext/transport/chttp2/transport/http2_errors.h"
 #include "src/core/lib/debug/trace.h"
+#include "src/core/lib/transport/http2_errors.h"
 
 #define MAX_MAX_HEADER_LIST_SIZE (1024 * 1024 * 1024)
 
@@ -52,21 +52,21 @@
 const grpc_chttp2_setting_parameters
     grpc_chttp2_settings_parameters[GRPC_CHTTP2_NUM_SETTINGS] = {
         {NULL, 0, 0, 0, GRPC_CHTTP2_DISCONNECT_ON_INVALID_VALUE,
-         GRPC_CHTTP2_PROTOCOL_ERROR},
+         GRPC_HTTP2_PROTOCOL_ERROR},
         {"HEADER_TABLE_SIZE", 4096, 0, 0xffffffff,
-         GRPC_CHTTP2_CLAMP_INVALID_VALUE, GRPC_CHTTP2_PROTOCOL_ERROR},
+         GRPC_CHTTP2_CLAMP_INVALID_VALUE, GRPC_HTTP2_PROTOCOL_ERROR},
         {"ENABLE_PUSH", 1, 0, 1, GRPC_CHTTP2_DISCONNECT_ON_INVALID_VALUE,
-         GRPC_CHTTP2_PROTOCOL_ERROR},
+         GRPC_HTTP2_PROTOCOL_ERROR},
         {"MAX_CONCURRENT_STREAMS", 0xffffffffu, 0, 0xffffffffu,
-         GRPC_CHTTP2_DISCONNECT_ON_INVALID_VALUE, GRPC_CHTTP2_PROTOCOL_ERROR},
+         GRPC_CHTTP2_DISCONNECT_ON_INVALID_VALUE, GRPC_HTTP2_PROTOCOL_ERROR},
         {"INITIAL_WINDOW_SIZE", 65535, 0, 0x7fffffffu,
          GRPC_CHTTP2_DISCONNECT_ON_INVALID_VALUE,
-         GRPC_CHTTP2_FLOW_CONTROL_ERROR},
+         GRPC_HTTP2_FLOW_CONTROL_ERROR},
         {"MAX_FRAME_SIZE", 16384, 16384, 16777215,
-         GRPC_CHTTP2_DISCONNECT_ON_INVALID_VALUE, GRPC_CHTTP2_PROTOCOL_ERROR},
+         GRPC_CHTTP2_DISCONNECT_ON_INVALID_VALUE, GRPC_HTTP2_PROTOCOL_ERROR},
         {"MAX_HEADER_LIST_SIZE", MAX_MAX_HEADER_LIST_SIZE, 0,
          MAX_MAX_HEADER_LIST_SIZE, GRPC_CHTTP2_CLAMP_INVALID_VALUE,
-         GRPC_CHTTP2_PROTOCOL_ERROR},
+         GRPC_HTTP2_PROTOCOL_ERROR},
 };
 
 static uint8_t *fill_header(uint8_t *out, uint32_t length, uint8_t flags) {

src/core/ext/transport/chttp2/transport/hpack_encoder.c

@@ -49,6 +49,7 @@
 #include "src/core/ext/transport/chttp2/transport/hpack_table.h"
 #include "src/core/ext/transport/chttp2/transport/varint.h"
 #include "src/core/lib/slice/slice_internal.h"
+#include "src/core/lib/slice/slice_string_helpers.h"
 #include "src/core/lib/transport/metadata.h"
 #include "src/core/lib/transport/static_metadata.h"
 #include "src/core/lib/transport/timeout_encoding.h"
@@ -64,6 +65,10 @@
 /* don't consider adding anything bigger than this to the hpack table */
 #define MAX_DECODER_SPACE_USAGE 512
 
+static grpc_slice_refcount terminal_slice_refcount = {NULL, NULL};
+static const grpc_slice terminal_slice = {&terminal_slice_refcount,
+                                          .data.refcounted = {0, 0}};
+
 extern int grpc_http_trace;
 
 typedef struct {
@@ -185,9 +190,12 @@ static void evict_entry(grpc_chttp2_hpack_compressor *c) {
 
 /* add an element to the decoder table */
 static void add_elem(grpc_exec_ctx *exec_ctx, grpc_chttp2_hpack_compressor *c,
-                     grpc_mdelem *elem) {
-  uint32_t key_hash = elem->key->hash;
-  uint32_t elem_hash = GRPC_MDSTR_KV_HASH(key_hash, elem->value->hash);
+                     grpc_mdelem elem) {
+  GPR_ASSERT(GRPC_MDELEM_IS_INTERNED(elem));
+
+  uint32_t key_hash = grpc_slice_hash(GRPC_MDKEY(elem));
+  uint32_t value_hash = grpc_slice_hash(GRPC_MDVALUE(elem));
+  uint32_t elem_hash = GRPC_MDSTR_KV_HASH(key_hash, value_hash);
   uint32_t new_index = c->tail_remote_index + c->table_elems + 1;
   size_t elem_size = grpc_mdelem_get_size_in_hpack_table(elem);
 
@@ -212,17 +220,18 @@ static void add_elem(grpc_exec_ctx *exec_ctx, grpc_chttp2_hpack_compressor *c,
   c->table_elems++;
 
   /* Store this element into {entries,indices}_elem */
-  if (c->entries_elems[HASH_FRAGMENT_2(elem_hash)] == elem) {
+  if (grpc_mdelem_eq(c->entries_elems[HASH_FRAGMENT_2(elem_hash)], elem)) {
     /* already there: update with new index */
     c->indices_elems[HASH_FRAGMENT_2(elem_hash)] = new_index;
-  } else if (c->entries_elems[HASH_FRAGMENT_3(elem_hash)] == elem) {
+  } else if (grpc_mdelem_eq(c->entries_elems[HASH_FRAGMENT_3(elem_hash)],
+                            elem)) {
     /* already there (cuckoo): update with new index */
     c->indices_elems[HASH_FRAGMENT_3(elem_hash)] = new_index;
-  } else if (c->entries_elems[HASH_FRAGMENT_2(elem_hash)] == NULL) {
+  } else if (GRPC_MDISNULL(c->entries_elems[HASH_FRAGMENT_2(elem_hash)])) {
     /* not there, but a free element: add */
     c->entries_elems[HASH_FRAGMENT_2(elem_hash)] = GRPC_MDELEM_REF(elem);
     c->indices_elems[HASH_FRAGMENT_2(elem_hash)] = new_index;
-  } else if (c->entries_elems[HASH_FRAGMENT_3(elem_hash)] == NULL) {
+  } else if (GRPC_MDISNULL(c->entries_elems[HASH_FRAGMENT_3(elem_hash)])) {
     /* not there (cuckoo), but a free element: add */
     c->entries_elems[HASH_FRAGMENT_3(elem_hash)] = GRPC_MDELEM_REF(elem);
     c->indices_elems[HASH_FRAGMENT_3(elem_hash)] = new_index;
@@ -241,24 +250,34 @@ static void add_elem(grpc_exec_ctx *exec_ctx, grpc_chttp2_hpack_compressor *c,
 
   /* do exactly the same for the key (so we can find by that again too) */
 
-  if (c->entries_keys[HASH_FRAGMENT_2(key_hash)] == elem->key) {
+  if (grpc_slice_eq(c->entries_keys[HASH_FRAGMENT_2(key_hash)],
+                    GRPC_MDKEY(elem))) {
     c->indices_keys[HASH_FRAGMENT_2(key_hash)] = new_index;
-  } else if (c->entries_keys[HASH_FRAGMENT_3(key_hash)] == elem->key) {
+  } else if (grpc_slice_eq(c->entries_keys[HASH_FRAGMENT_3(key_hash)],
+                           GRPC_MDKEY(elem))) {
     c->indices_keys[HASH_FRAGMENT_3(key_hash)] = new_index;
-  } else if (c->entries_keys[HASH_FRAGMENT_2(key_hash)] == NULL) {
-    c->entries_keys[HASH_FRAGMENT_2(key_hash)] = GRPC_MDSTR_REF(elem->key);
+  } else if (c->entries_keys[HASH_FRAGMENT_2(key_hash)].refcount ==
+             &terminal_slice_refcount) {
+    c->entries_keys[HASH_FRAGMENT_2(key_hash)] =
+        grpc_slice_ref_internal(GRPC_MDKEY(elem));
     c->indices_keys[HASH_FRAGMENT_2(key_hash)] = new_index;
-  } else if (c->entries_keys[HASH_FRAGMENT_3(key_hash)] == NULL) {
-    c->entries_keys[HASH_FRAGMENT_3(key_hash)] = GRPC_MDSTR_REF(elem->key);
+  } else if (c->entries_keys[HASH_FRAGMENT_3(key_hash)].refcount ==
+             &terminal_slice_refcount) {
+    c->entries_keys[HASH_FRAGMENT_3(key_hash)] =
+        grpc_slice_ref_internal(GRPC_MDKEY(elem));
     c->indices_keys[HASH_FRAGMENT_3(key_hash)] = new_index;
   } else if (c->indices_keys[HASH_FRAGMENT_2(key_hash)] <
              c->indices_keys[HASH_FRAGMENT_3(key_hash)]) {
-    GRPC_MDSTR_UNREF(exec_ctx, c->entries_keys[HASH_FRAGMENT_2(key_hash)]);
-    c->entries_keys[HASH_FRAGMENT_2(key_hash)] = GRPC_MDSTR_REF(elem->key);
+    grpc_slice_unref_internal(exec_ctx,
+                              c->entries_keys[HASH_FRAGMENT_2(key_hash)]);
+    c->entries_keys[HASH_FRAGMENT_2(key_hash)] =
+        grpc_slice_ref_internal(GRPC_MDKEY(elem));
     c->indices_keys[HASH_FRAGMENT_2(key_hash)] = new_index;
   } else {
-    GRPC_MDSTR_UNREF(exec_ctx, c->entries_keys[HASH_FRAGMENT_3(key_hash)]);
-    c->entries_keys[HASH_FRAGMENT_3(key_hash)] = GRPC_MDSTR_REF(elem->key);
+    grpc_slice_unref_internal(exec_ctx,
+                              c->entries_keys[HASH_FRAGMENT_3(key_hash)]);
+    c->entries_keys[HASH_FRAGMENT_3(key_hash)] =
+        grpc_slice_ref_internal(GRPC_MDKEY(elem));
     c->indices_keys[HASH_FRAGMENT_3(key_hash)] = new_index;
   }
 }
@@ -270,20 +289,18 @@ static void emit_indexed(grpc_chttp2_hpack_compressor *c, uint32_t elem_index,
                            len);
 }
 
-static grpc_slice get_wire_value(grpc_mdelem *elem, uint8_t *huffman_prefix) {
-  if (grpc_is_binary_header(
-          (const char *)GRPC_SLICE_START_PTR(elem->key->slice),
-          GRPC_SLICE_LENGTH(elem->key->slice))) {
+static grpc_slice get_wire_value(grpc_mdelem elem, uint8_t *huffman_prefix) {
+  if (grpc_is_binary_header(GRPC_MDKEY(elem))) {
     *huffman_prefix = 0x80;
-    return grpc_mdstr_as_base64_encoded_and_huffman_compressed(elem->value);
+    return grpc_chttp2_base64_encode_and_huffman_compress(GRPC_MDVALUE(elem));
   }
   /* TODO(ctiller): opportunistically compress non-binary headers */
   *huffman_prefix = 0x00;
-  return elem->value->slice;
+  return grpc_slice_ref_internal(GRPC_MDVALUE(elem));
 }
 
 static void emit_lithdr_incidx(grpc_chttp2_hpack_compressor *c,
-                               uint32_t key_index, grpc_mdelem *elem,
+                               uint32_t key_index, grpc_mdelem elem,
                                framer_state *st) {
   uint32_t len_pfx = GRPC_CHTTP2_VARINT_LENGTH(key_index, 2);
   uint8_t huffman_prefix;
@@ -296,11 +313,11 @@ static void emit_lithdr_incidx(grpc_chttp2_hpack_compressor *c,
                            add_tiny_header_data(st, len_pfx), len_pfx);
   GRPC_CHTTP2_WRITE_VARINT((uint32_t)len_val, 1, huffman_prefix,
                            add_tiny_header_data(st, len_val_len), len_val_len);
-  add_header_data(st, grpc_slice_ref_internal(value_slice));
+  add_header_data(st, value_slice);
 }
 
 static void emit_lithdr_noidx(grpc_chttp2_hpack_compressor *c,
-                              uint32_t key_index, grpc_mdelem *elem,
+                              uint32_t key_index, grpc_mdelem elem,
                               framer_state *st) {
   uint32_t len_pfx = GRPC_CHTTP2_VARINT_LENGTH(key_index, 4);
   uint8_t huffman_prefix;
@@ -313,12 +330,12 @@ static void emit_lithdr_noidx(grpc_chttp2_hpack_compressor *c,
                            add_tiny_header_data(st, len_pfx), len_pfx);
   GRPC_CHTTP2_WRITE_VARINT((uint32_t)len_val, 1, huffman_prefix,
                            add_tiny_header_data(st, len_val_len), len_val_len);
-  add_header_data(st, grpc_slice_ref_internal(value_slice));
+  add_header_data(st, value_slice);
 }
 
 static void emit_lithdr_incidx_v(grpc_chttp2_hpack_compressor *c,
-                                 grpc_mdelem *elem, framer_state *st) {
-  uint32_t len_key = (uint32_t)GRPC_SLICE_LENGTH(elem->key->slice);
+                                 grpc_mdelem elem, framer_state *st) {
+  uint32_t len_key = (uint32_t)GRPC_SLICE_LENGTH(GRPC_MDKEY(elem));
   uint8_t huffman_prefix;
   grpc_slice value_slice = get_wire_value(elem, &huffman_prefix);
   uint32_t len_val = (uint32_t)GRPC_SLICE_LENGTH(value_slice);
@@ -329,15 +346,15 @@ static void emit_lithdr_incidx_v(grpc_chttp2_hpack_compressor *c,
   *add_tiny_header_data(st, 1) = 0x40;
   GRPC_CHTTP2_WRITE_VARINT(len_key, 1, 0x00,
                            add_tiny_header_data(st, len_key_len), len_key_len);
-  add_header_data(st, grpc_slice_ref_internal(elem->key->slice));
+  add_header_data(st, grpc_slice_ref_internal(GRPC_MDKEY(elem)));
   GRPC_CHTTP2_WRITE_VARINT(len_val, 1, huffman_prefix,
                            add_tiny_header_data(st, len_val_len), len_val_len);
-  add_header_data(st, grpc_slice_ref_internal(value_slice));
+  add_header_data(st, value_slice);
 }
 
 static void emit_lithdr_noidx_v(grpc_chttp2_hpack_compressor *c,
-                                grpc_mdelem *elem, framer_state *st) {
-  uint32_t len_key = (uint32_t)GRPC_SLICE_LENGTH(elem->key->slice);
+                                grpc_mdelem elem, framer_state *st) {
+  uint32_t len_key = (uint32_t)GRPC_SLICE_LENGTH(GRPC_MDKEY(elem));
   uint8_t huffman_prefix;
   grpc_slice value_slice = get_wire_value(elem, &huffman_prefix);
   uint32_t len_val = (uint32_t)GRPC_SLICE_LENGTH(value_slice);
@@ -348,10 +365,10 @@ static void emit_lithdr_noidx_v(grpc_chttp2_hpack_compressor *c,
   *add_tiny_header_data(st, 1) = 0x00;
   GRPC_CHTTP2_WRITE_VARINT(len_key, 1, 0x00,
                            add_tiny_header_data(st, len_key_len), len_key_len);
-  add_header_data(st, grpc_slice_ref_internal(elem->key->slice));
+  add_header_data(st, grpc_slice_ref_internal(GRPC_MDKEY(elem)));
   GRPC_CHTTP2_WRITE_VARINT(len_val, 1, huffman_prefix,
                            add_tiny_header_data(st, len_val_len), len_val_len);
-  add_header_data(st, grpc_slice_ref_internal(value_slice));
+  add_header_data(st, value_slice);
 }
 
 static void emit_advertise_table_size_change(grpc_chttp2_hpack_compressor *c,
@@ -369,15 +386,9 @@ static uint32_t dynidx(grpc_chttp2_hpack_compressor *c, uint32_t elem_index) {
 
 /* encode an mdelem */
 static void hpack_enc(grpc_exec_ctx *exec_ctx, grpc_chttp2_hpack_compressor *c,
-                      grpc_mdelem *elem, framer_state *st) {
-  uint32_t key_hash = elem->key->hash;
-  uint32_t elem_hash = GRPC_MDSTR_KV_HASH(key_hash, elem->value->hash);
-  size_t decoder_space_usage;
-  uint32_t indices_key;
-  int should_add_elem;
-
-  GPR_ASSERT(GRPC_SLICE_LENGTH(elem->key->slice) > 0);
-  if (GRPC_SLICE_START_PTR(elem->key->slice)[0] != ':') { /* regular header */
+                      grpc_mdelem elem, framer_state *st) {
+  GPR_ASSERT(GRPC_SLICE_LENGTH(GRPC_MDKEY(elem)) > 0);
+  if (GRPC_SLICE_START_PTR(GRPC_MDKEY(elem))[0] != ':') { /* regular header */
     st->seen_regular_header = 1;
   } else {
     GPR_ASSERT(
@@ -385,11 +396,39 @@ static void hpack_enc(grpc_exec_ctx *exec_ctx, grpc_chttp2_hpack_compressor *c,
         "Reserved header (colon-prefixed) happening after regular ones.");
   }
 
+  if (grpc_http_trace && !GRPC_MDELEM_IS_INTERNED(elem)) {
+    char *k = grpc_slice_to_c_string(GRPC_MDKEY(elem));
+    char *v = grpc_slice_to_c_string(GRPC_MDVALUE(elem));
+    gpr_log(
+        GPR_DEBUG,
+        "Encode: '%s: %s', elem_interned=%d [%d], k_interned=%d, v_interned=%d",
+        k, v, GRPC_MDELEM_IS_INTERNED(elem), GRPC_MDELEM_STORAGE(elem),
+        grpc_slice_is_interned(GRPC_MDKEY(elem)),
+        grpc_slice_is_interned(GRPC_MDVALUE(elem)));
+    gpr_free(k);
+    gpr_free(v);
+  }
+  if (!GRPC_MDELEM_IS_INTERNED(elem)) {
+    emit_lithdr_noidx_v(c, elem, st);
+    return;
+  }
+
+  uint32_t key_hash;
+  uint32_t value_hash;
+  uint32_t elem_hash;
+  size_t decoder_space_usage;
+  uint32_t indices_key;
+  int should_add_elem;
+
+  key_hash = grpc_slice_hash(GRPC_MDKEY(elem));
+  value_hash = grpc_slice_hash(GRPC_MDVALUE(elem));
+  elem_hash = GRPC_MDSTR_KV_HASH(key_hash, value_hash);
+
   inc_filter(HASH_FRAGMENT_1(elem_hash), &c->filter_elems_sum, c->filter_elems);
 
   /* is this elem currently in the decoders table? */
 
-  if (c->entries_elems[HASH_FRAGMENT_2(elem_hash)] == elem &&
+  if (grpc_mdelem_eq(c->entries_elems[HASH_FRAGMENT_2(elem_hash)], elem) &&
       c->indices_elems[HASH_FRAGMENT_2(elem_hash)] > c->tail_remote_index) {
     /* HIT: complete element (first cuckoo hash) */
     emit_indexed(c, dynidx(c, c->indices_elems[HASH_FRAGMENT_2(elem_hash)]),
@@ -397,7 +436,7 @@ static void hpack_enc(grpc_exec_ctx *exec_ctx, grpc_chttp2_hpack_compressor *c,
     return;
   }
 
-  if (c->entries_elems[HASH_FRAGMENT_3(elem_hash)] == elem &&
+  if (grpc_mdelem_eq(c->entries_elems[HASH_FRAGMENT_3(elem_hash)], elem) &&
       c->indices_elems[HASH_FRAGMENT_3(elem_hash)] > c->tail_remote_index) {
     /* HIT: complete element (second cuckoo hash) */
     emit_indexed(c, dynidx(c, c->indices_elems[HASH_FRAGMENT_3(elem_hash)]),
@@ -414,7 +453,8 @@ static void hpack_enc(grpc_exec_ctx *exec_ctx, grpc_chttp2_hpack_compressor *c,
   /* no hits for the elem... maybe there's a key? */
 
   indices_key = c->indices_keys[HASH_FRAGMENT_2(key_hash)];
-  if (c->entries_keys[HASH_FRAGMENT_2(key_hash)] == elem->key &&
+  if (grpc_slice_eq(c->entries_keys[HASH_FRAGMENT_2(key_hash)],
+                    GRPC_MDKEY(elem)) &&
       indices_key > c->tail_remote_index) {
     /* HIT: key (first cuckoo hash) */
     if (should_add_elem) {
@@ -429,7 +469,8 @@ static void hpack_enc(grpc_exec_ctx *exec_ctx, grpc_chttp2_hpack_compressor *c,
   }
 
   indices_key = c->indices_keys[HASH_FRAGMENT_3(key_hash)];
-  if (c->entries_keys[HASH_FRAGMENT_3(key_hash)] == elem->key &&
+  if (grpc_slice_eq(c->entries_keys[HASH_FRAGMENT_3(key_hash)],
+                    GRPC_MDKEY(elem)) &&
       indices_key > c->tail_remote_index) {
     /* HIT: key (first cuckoo hash) */
     if (should_add_elem) {
@@ -463,11 +504,11 @@ static void deadline_enc(grpc_exec_ctx *exec_ctx,
                          grpc_chttp2_hpack_compressor *c, gpr_timespec deadline,
                          framer_state *st) {
   char timeout_str[GRPC_HTTP2_TIMEOUT_ENCODE_MIN_BUFSIZE];
-  grpc_mdelem *mdelem;
+  grpc_mdelem mdelem;
   grpc_http2_encode_timeout(
       gpr_time_sub(deadline, gpr_now(deadline.clock_type)), timeout_str);
-  mdelem = grpc_mdelem_from_metadata_strings(
-      exec_ctx, GRPC_MDSTR_GRPC_TIMEOUT, grpc_mdstr_from_string(timeout_str));
+  mdelem = grpc_mdelem_from_slices(exec_ctx, GRPC_MDSTR_GRPC_TIMEOUT,
+                                   grpc_slice_from_copied_string(timeout_str));
   hpack_enc(exec_ctx, c, mdelem, st);
   GRPC_MDELEM_UNREF(exec_ctx, mdelem);
 }
@@ -484,14 +525,19 @@ void grpc_chttp2_hpack_compressor_init(grpc_chttp2_hpack_compressor *c) {
       gpr_malloc(sizeof(*c->table_elem_size) * c->cap_table_elems);
   memset(c->table_elem_size, 0,
          sizeof(*c->table_elem_size) * c->cap_table_elems);
+  for (size_t i = 0; i < GPR_ARRAY_SIZE(c->entries_keys); i++) {
+    c->entries_keys[i] = terminal_slice;
+  }
 }
 
 void grpc_chttp2_hpack_compressor_destroy(grpc_exec_ctx *exec_ctx,
                                           grpc_chttp2_hpack_compressor *c) {
   int i;
   for (i = 0; i < GRPC_CHTTP2_HPACKC_NUM_VALUES; i++) {
-    if (c->entries_keys[i]) GRPC_MDSTR_UNREF(exec_ctx, c->entries_keys[i]);
-    if (c->entries_elems[i]) GRPC_MDELEM_UNREF(exec_ctx, c->entries_elems[i]);
+    if (c->entries_keys[i].refcount != &terminal_slice_refcount) {
+      grpc_slice_unref_internal(exec_ctx, c->entries_keys[i]);
+    }
+    GRPC_MDELEM_UNREF(exec_ctx, c->entries_elems[i]);
   }
   gpr_free(c->table_elem_size);
 }

src/core/ext/transport/chttp2/transport/hpack_encoder.h

@@ -74,8 +74,8 @@ typedef struct {
 
   /* entry tables for keys & elems: these tables track values that have been
      seen and *may* be in the decompressor table */
-  grpc_mdstr *entries_keys[GRPC_CHTTP2_HPACKC_NUM_VALUES];
-  grpc_mdelem *entries_elems[GRPC_CHTTP2_HPACKC_NUM_VALUES];
+  grpc_slice entries_keys[GRPC_CHTTP2_HPACKC_NUM_VALUES];
+  grpc_mdelem entries_elems[GRPC_CHTTP2_HPACKC_NUM_VALUES];
   uint32_t indices_keys[GRPC_CHTTP2_HPACKC_NUM_VALUES];
   uint32_t indices_elems[GRPC_CHTTP2_HPACKC_NUM_VALUES];
 

src/core/ext/transport/chttp2/transport/hpack_parser.c

@@ -50,9 +50,13 @@
 #include <grpc/support/useful.h>
 
 #include "src/core/ext/transport/chttp2/transport/bin_encoder.h"
-#include "src/core/ext/transport/chttp2/transport/http2_errors.h"
 #include "src/core/lib/profiling/timers.h"
+#include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/support/string.h"
+#include "src/core/lib/transport/http2_errors.h"
+
+/* TODO(ctiller): remove before submission */
+#include "src/core/lib/slice/slice_string_helpers.h"
 
 extern int grpc_http_trace;
 
@@ -668,8 +672,22 @@ static const uint8_t inverse_base64[256] = {
 
 /* emission helpers */
 static grpc_error *on_hdr(grpc_exec_ctx *exec_ctx, grpc_chttp2_hpack_parser *p,
-                          grpc_mdelem *md, int add_to_table) {
+                          grpc_mdelem md, int add_to_table) {
+  if (grpc_http_trace && !GRPC_MDELEM_IS_INTERNED(md)) {
+    char *k = grpc_slice_to_c_string(GRPC_MDKEY(md));
+    char *v = grpc_slice_to_c_string(GRPC_MDVALUE(md));
+    gpr_log(
+        GPR_DEBUG,
+        "Decode: '%s: %s', elem_interned=%d [%d], k_interned=%d, v_interned=%d",
+        k, v, GRPC_MDELEM_IS_INTERNED(md), GRPC_MDELEM_STORAGE(md),
+        grpc_slice_is_interned(GRPC_MDKEY(md)),
+        grpc_slice_is_interned(GRPC_MDVALUE(md)));
+    gpr_free(k);
+    gpr_free(v);
+  }
   if (add_to_table) {
+    GPR_ASSERT(GRPC_MDELEM_STORAGE(md) == GRPC_MDELEM_STORAGE_INTERNED ||
+               GRPC_MDELEM_STORAGE(md) == GRPC_MDELEM_STORAGE_STATIC);
     grpc_error *err = grpc_chttp2_hptbl_add(exec_ctx, &p->table, md);
     if (err != GRPC_ERROR_NONE) return err;
   }
@@ -681,10 +699,28 @@ static grpc_error *on_hdr(grpc_exec_ctx *exec_ctx, grpc_chttp2_hpack_parser *p,
   return GRPC_ERROR_NONE;
 }
 
-static grpc_mdstr *take_string(grpc_chttp2_hpack_parser *p,
-                               grpc_chttp2_hpack_parser_string *str) {
-  grpc_mdstr *s = grpc_mdstr_from_buffer((uint8_t *)str->str, str->length);
-  str->length = 0;
+static grpc_slice take_string(grpc_exec_ctx *exec_ctx,
+                              grpc_chttp2_hpack_parser *p,
+                              grpc_chttp2_hpack_parser_string *str,
+                              bool intern) {
+  grpc_slice s;
+  if (!str->copied) {
+    if (intern) {
+      s = grpc_slice_intern(str->data.referenced);
+      grpc_slice_unref_internal(exec_ctx, str->data.referenced);
+    } else {
+      s = str->data.referenced;
+    }
+    str->copied = true;
+    str->data.referenced = grpc_empty_slice();
+  } else if (intern) {
+    s = grpc_slice_intern(grpc_slice_from_static_buffer(
+        str->data.copied.str, str->data.copied.length));
+  } else {
+    s = grpc_slice_from_copied_buffer(str->data.copied.str,
+                                      str->data.copied.length);
+  }
+  str->data.copied.length = 0;
   return s;
 }
 
@@ -771,8 +807,8 @@ static grpc_error *finish_indexed_field(grpc_exec_ctx *exec_ctx,
                                         grpc_chttp2_hpack_parser *p,
                                         const uint8_t *cur,
                                         const uint8_t *end) {
-  grpc_mdelem *md = grpc_chttp2_hptbl_lookup(&p->table, p->index);
-  if (md == NULL) {
+  grpc_mdelem md = grpc_chttp2_hptbl_lookup(&p->table, p->index);
+  if (GRPC_MDISNULL(md)) {
     return grpc_error_set_int(
         grpc_error_set_int(GRPC_ERROR_CREATE("Invalid HPACK index received"),
                            GRPC_ERROR_INT_INDEX, (intptr_t)p->index),
@@ -813,12 +849,13 @@ static grpc_error *finish_lithdr_incidx(grpc_exec_ctx *exec_ctx,
                                         grpc_chttp2_hpack_parser *p,
                                         const uint8_t *cur,
                                         const uint8_t *end) {
-  grpc_mdelem *md = grpc_chttp2_hptbl_lookup(&p->table, p->index);
-  GPR_ASSERT(md != NULL); /* handled in string parsing */
-  grpc_error *err = on_hdr(exec_ctx, p, grpc_mdelem_from_metadata_strings(
-                                            exec_ctx, GRPC_MDSTR_REF(md->key),
-                                            take_string(p, &p->value)),
-                           1);
+  grpc_mdelem md = grpc_chttp2_hptbl_lookup(&p->table, p->index);
+  GPR_ASSERT(!GRPC_MDISNULL(md)); /* handled in string parsing */
+  grpc_error *err = on_hdr(
+      exec_ctx, p,
+      grpc_mdelem_from_slices(exec_ctx, grpc_slice_ref_internal(GRPC_MDKEY(md)),
+                              take_string(exec_ctx, p, &p->value, true)),
+      1);
   if (err != GRPC_ERROR_NONE) return parse_error(exec_ctx, p, cur, end, err);
   return parse_begin(exec_ctx, p, cur, end);
 }
@@ -828,10 +865,11 @@ static grpc_error *finish_lithdr_incidx_v(grpc_exec_ctx *exec_ctx,
                                           grpc_chttp2_hpack_parser *p,
                                           const uint8_t *cur,
                                           const uint8_t *end) {
-  grpc_error *err = on_hdr(exec_ctx, p, grpc_mdelem_from_metadata_strings(
-                                            exec_ctx, take_string(p, &p->key),
-                                            take_string(p, &p->value)),
-                           1);
+  grpc_error *err = on_hdr(
+      exec_ctx, p,
+      grpc_mdelem_from_slices(exec_ctx, take_string(exec_ctx, p, &p->key, true),
+                              take_string(exec_ctx, p, &p->value, true)),
+      1);
   if (err != GRPC_ERROR_NONE) return parse_error(exec_ctx, p, cur, end, err);
   return parse_begin(exec_ctx, p, cur, end);
 }
@@ -881,12 +919,13 @@ static grpc_error *finish_lithdr_notidx(grpc_exec_ctx *exec_ctx,
                                         grpc_chttp2_hpack_parser *p,
                                         const uint8_t *cur,
                                         const uint8_t *end) {
-  grpc_mdelem *md = grpc_chttp2_hptbl_lookup(&p->table, p->index);
-  GPR_ASSERT(md != NULL); /* handled in string parsing */
-  grpc_error *err = on_hdr(exec_ctx, p, grpc_mdelem_from_metadata_strings(
-                                            exec_ctx, GRPC_MDSTR_REF(md->key),
-                                            take_string(p, &p->value)),
-                           0);
+  grpc_mdelem md = grpc_chttp2_hptbl_lookup(&p->table, p->index);
+  GPR_ASSERT(!GRPC_MDISNULL(md)); /* handled in string parsing */
+  grpc_error *err = on_hdr(
+      exec_ctx, p,
+      grpc_mdelem_from_slices(exec_ctx, grpc_slice_ref_internal(GRPC_MDKEY(md)),
+                              take_string(exec_ctx, p, &p->value, false)),
+      0);
   if (err != GRPC_ERROR_NONE) return parse_error(exec_ctx, p, cur, end, err);
   return parse_begin(exec_ctx, p, cur, end);
 }
@@ -896,10 +935,11 @@ static grpc_error *finish_lithdr_notidx_v(grpc_exec_ctx *exec_ctx,
                                           grpc_chttp2_hpack_parser *p,
                                           const uint8_t *cur,
                                           const uint8_t *end) {
-  grpc_error *err = on_hdr(exec_ctx, p, grpc_mdelem_from_metadata_strings(
-                                            exec_ctx, take_string(p, &p->key),
-                                            take_string(p, &p->value)),
-                           0);
+  grpc_error *err = on_hdr(
+      exec_ctx, p,
+      grpc_mdelem_from_slices(exec_ctx, take_string(exec_ctx, p, &p->key, true),
+                              take_string(exec_ctx, p, &p->value, false)),
+      0);
   if (err != GRPC_ERROR_NONE) return parse_error(exec_ctx, p, cur, end, err);
   return parse_begin(exec_ctx, p, cur, end);
 }
@@ -949,12 +989,13 @@ static grpc_error *finish_lithdr_nvridx(grpc_exec_ctx *exec_ctx,
                                         grpc_chttp2_hpack_parser *p,
                                         const uint8_t *cur,
                                         const uint8_t *end) {
-  grpc_mdelem *md = grpc_chttp2_hptbl_lookup(&p->table, p->index);
-  GPR_ASSERT(md != NULL); /* handled in string parsing */
-  grpc_error *err = on_hdr(exec_ctx, p, grpc_mdelem_from_metadata_strings(
-                                            exec_ctx, GRPC_MDSTR_REF(md->key),
-                                            take_string(p, &p->value)),
-                           0);
+  grpc_mdelem md = grpc_chttp2_hptbl_lookup(&p->table, p->index);
+  GPR_ASSERT(!GRPC_MDISNULL(md)); /* handled in string parsing */
+  grpc_error *err = on_hdr(
+      exec_ctx, p,
+      grpc_mdelem_from_slices(exec_ctx, grpc_slice_ref_internal(GRPC_MDKEY(md)),
+                              take_string(exec_ctx, p, &p->value, false)),
+      0);
   if (err != GRPC_ERROR_NONE) return parse_error(exec_ctx, p, cur, end, err);
   return parse_begin(exec_ctx, p, cur, end);
 }
@@ -964,10 +1005,11 @@ static grpc_error *finish_lithdr_nvridx_v(grpc_exec_ctx *exec_ctx,
                                           grpc_chttp2_hpack_parser *p,
                                           const uint8_t *cur,
                                           const uint8_t *end) {
-  grpc_error *err = on_hdr(exec_ctx, p, grpc_mdelem_from_metadata_strings(
-                                            exec_ctx, take_string(p, &p->key),
-                                            take_string(p, &p->value)),
-                           0);
+  grpc_error *err = on_hdr(
+      exec_ctx, p,
+      grpc_mdelem_from_slices(exec_ctx, take_string(exec_ctx, p, &p->key, true),
+                              take_string(exec_ctx, p, &p->value, false)),
+      0);
   if (err != GRPC_ERROR_NONE) return parse_error(exec_ctx, p, cur, end, err);
   return parse_begin(exec_ctx, p, cur, end);
 }
@@ -1261,14 +1303,15 @@ static grpc_error *parse_string_prefix(grpc_exec_ctx *exec_ctx,
 static void append_bytes(grpc_chttp2_hpack_parser_string *str,
                          const uint8_t *data, size_t length) {
   if (length == 0) return;
-  if (length + str->length > str->capacity) {
-    GPR_ASSERT(str->length + length <= UINT32_MAX);
-    str->capacity = (uint32_t)(str->length + length);
-    str->str = gpr_realloc(str->str, str->capacity);
+  if (length + str->data.copied.length > str->data.copied.capacity) {
+    GPR_ASSERT(str->data.copied.length + length <= UINT32_MAX);
+    str->data.copied.capacity = (uint32_t)(str->data.copied.length + length);
+    str->data.copied.str =
+        gpr_realloc(str->data.copied.str, str->data.copied.capacity);
   }
-  memcpy(str->str + str->length, data, length);
-  GPR_ASSERT(length <= UINT32_MAX - str->length);
-  str->length += (uint32_t)length;
+  memcpy(str->data.copied.str + str->data.copied.length, data, length);
+  GPR_ASSERT(length <= UINT32_MAX - str->data.copied.length);
+  str->data.copied.length += (uint32_t)length;
 }
 
 static grpc_error *append_string(grpc_exec_ctx *exec_ctx,
@@ -1351,11 +1394,9 @@ static grpc_error *append_string(grpc_exec_ctx *exec_ctx,
       exec_ctx, p, cur, end, GRPC_ERROR_CREATE("Should never reach here")));
 }
 
-/* append a null terminator to a string */
 static grpc_error *finish_str(grpc_exec_ctx *exec_ctx,
                               grpc_chttp2_hpack_parser *p, const uint8_t *cur,
                               const uint8_t *end) {
-  uint8_t terminator = 0;
   uint8_t decoded[2];
   uint32_t bits;
   grpc_chttp2_hpack_parser_string *str = p->parsing.str;
@@ -1396,8 +1437,6 @@ static grpc_error *finish_str(grpc_exec_ctx *exec_ctx,
       append_bytes(str, decoded, 2);
       break;
   }
-  append_bytes(str, &terminator, 1);
-  p->parsing.str->length--; /* don't actually count the null terminator */
   return GRPC_ERROR_NONE;
 }
 
@@ -1472,8 +1511,18 @@ static grpc_error *begin_parse_string(grpc_exec_ctx *exec_ctx,
                                       const uint8_t *cur, const uint8_t *end,
                                       uint8_t binary,
                                       grpc_chttp2_hpack_parser_string *str) {
+  if (!p->huff && binary == NOT_BINARY && (end - cur) >= (intptr_t)p->strlen &&
+      p->current_slice_refcount != NULL) {
+    str->copied = false;
+    str->data.referenced.refcount = p->current_slice_refcount;
+    str->data.referenced.data.refcounted.bytes = (uint8_t *)cur;
+    str->data.referenced.data.refcounted.length = p->strlen;
+    grpc_slice_ref_internal(str->data.referenced);
+    return parse_next(exec_ctx, p, cur + p->strlen, end);
+  }
   p->strgot = 0;
-  str->length = 0;
+  str->copied = true;
+  str->data.copied.length = 0;
   p->parsing.str = str;
   p->huff_state = 0;
   p->binary = binary;
@@ -1490,21 +1539,22 @@ static grpc_error *parse_key_string(grpc_exec_ctx *exec_ctx,
 /* check if a key represents a binary header or not */
 
 static bool is_binary_literal_header(grpc_chttp2_hpack_parser *p) {
-  return grpc_is_binary_header(p->key.str, p->key.length);
+  return grpc_is_binary_header(
+      p->key.copied ? grpc_slice_from_static_buffer(p->key.data.copied.str,
+                                                    p->key.data.copied.length)
+                    : p->key.data.referenced);
 }
 
 static grpc_error *is_binary_indexed_header(grpc_chttp2_hpack_parser *p,
                                             bool *is) {
-  grpc_mdelem *elem = grpc_chttp2_hptbl_lookup(&p->table, p->index);
-  if (!elem) {
+  grpc_mdelem elem = grpc_chttp2_hptbl_lookup(&p->table, p->index);
+  if (GRPC_MDISNULL(elem)) {
     return grpc_error_set_int(
         grpc_error_set_int(GRPC_ERROR_CREATE("Invalid HPACK index received"),
                            GRPC_ERROR_INT_INDEX, (intptr_t)p->index),
         GRPC_ERROR_INT_SIZE, (intptr_t)p->table.num_ents);
   }
-  *is = grpc_is_binary_header(
-      (const char *)GRPC_SLICE_START_PTR(elem->key->slice),
-      GRPC_SLICE_LENGTH(elem->key->slice));
+  *is = grpc_is_binary_header(GRPC_MDKEY(elem));
   return GRPC_ERROR_NONE;
 }
 
@@ -1539,12 +1589,14 @@ void grpc_chttp2_hpack_parser_init(grpc_exec_ctx *exec_ctx,
   p->on_header = NULL;
   p->on_header_user_data = NULL;
   p->state = parse_begin;
-  p->key.str = NULL;
-  p->key.capacity = 0;
-  p->key.length = 0;
-  p->value.str = NULL;
-  p->value.capacity = 0;
-  p->value.length = 0;
+  p->key.data.referenced = grpc_empty_slice();
+  p->key.data.copied.str = NULL;
+  p->key.data.copied.capacity = 0;
+  p->key.data.copied.length = 0;
+  p->value.data.referenced = grpc_empty_slice();
+  p->value.data.copied.str = NULL;
+  p->value.data.copied.capacity = 0;
+  p->value.data.copied.length = 0;
   p->dynamic_table_update_allowed = 2;
   p->last_error = GRPC_ERROR_NONE;
   grpc_chttp2_hptbl_init(exec_ctx, &p->table);
@@ -1559,19 +1611,24 @@ void grpc_chttp2_hpack_parser_destroy(grpc_exec_ctx *exec_ctx,
                                       grpc_chttp2_hpack_parser *p) {
   grpc_chttp2_hptbl_destroy(exec_ctx, &p->table);
   GRPC_ERROR_UNREF(p->last_error);
-  gpr_free(p->key.str);
-  gpr_free(p->value.str);
+  grpc_slice_unref_internal(exec_ctx, p->key.data.referenced);
+  grpc_slice_unref_internal(exec_ctx, p->value.data.referenced);
+  gpr_free(p->key.data.copied.str);
+  gpr_free(p->value.data.copied.str);
 }
 
 grpc_error *grpc_chttp2_hpack_parser_parse(grpc_exec_ctx *exec_ctx,
                                            grpc_chttp2_hpack_parser *p,
-                                           const uint8_t *beg,
-                                           const uint8_t *end) {
+                                           grpc_slice slice) {
   /* TODO(ctiller): limit the distance of end from beg, and perform multiple
      steps in the event of a large chunk of data to limit
      stack space usage when no tail call optimization is
      available */
-  return p->state(exec_ctx, p, beg, end);
+  p->current_slice_refcount = slice.refcount;
+  grpc_error *error = p->state(exec_ctx, p, GRPC_SLICE_START_PTR(slice),
+                               GRPC_SLICE_END_PTR(slice));
+  p->current_slice_refcount = NULL;
+  return error;
 }
 
 typedef void (*maybe_complete_func_type)(grpc_exec_ctx *exec_ctx,
@@ -1587,7 +1644,7 @@ static void force_client_rst_stream(grpc_exec_ctx *exec_ctx, void *sp,
   grpc_chttp2_transport *t = s->t;
   if (!s->write_closed) {
     grpc_slice_buffer_add(
-        &t->qbuf, grpc_chttp2_rst_stream_create(s->id, GRPC_CHTTP2_NO_ERROR,
+        &t->qbuf, grpc_chttp2_rst_stream_create(s->id, GRPC_HTTP2_NO_ERROR,
                                                 &s->stats.outgoing));
     grpc_chttp2_initiate_write(exec_ctx, t, false, "force_rst_stream");
     grpc_chttp2_mark_stream_closed(exec_ctx, t, s, true, true, GRPC_ERROR_NONE);
@@ -1605,8 +1662,7 @@ grpc_error *grpc_chttp2_header_parser_parse(grpc_exec_ctx *exec_ctx,
   if (s != NULL) {
     s->stats.incoming.header_bytes += GRPC_SLICE_LENGTH(slice);
   }
-  grpc_error *error = grpc_chttp2_hpack_parser_parse(
-      exec_ctx, parser, GRPC_SLICE_START_PTR(slice), GRPC_SLICE_END_PTR(slice));
+  grpc_error *error = grpc_chttp2_hpack_parser_parse(exec_ctx, parser, slice);
   if (error != GRPC_ERROR_NONE) {
     GPR_TIMER_END("grpc_chttp2_hpack_parser_parse", 0);
     return error;

src/core/ext/transport/chttp2/transport/hpack_parser.h

@@ -49,14 +49,20 @@ typedef grpc_error *(*grpc_chttp2_hpack_parser_state)(
     const uint8_t *end);
 
 typedef struct {
-  char *str;
-  uint32_t length;
-  uint32_t capacity;
+  bool copied;
+  struct {
+    grpc_slice referenced;
+    struct {
+      char *str;
+      uint32_t length;
+      uint32_t capacity;
+    } copied;
+  } data;
 } grpc_chttp2_hpack_parser_string;
 
 struct grpc_chttp2_hpack_parser {
   /* user specified callback for each header output */
-  void (*on_header)(grpc_exec_ctx *exec_ctx, void *user_data, grpc_mdelem *md);
+  void (*on_header)(grpc_exec_ctx *exec_ctx, void *user_data, grpc_mdelem md);
   void *on_header_user_data;
 
   grpc_error *last_error;
@@ -67,6 +73,8 @@ struct grpc_chttp2_hpack_parser {
   const grpc_chttp2_hpack_parser_state *next_state;
   /* what to do after skipping prioritization data */
   grpc_chttp2_hpack_parser_state after_prioritization;
+  /* the refcount of the slice that we're currently parsing */
+  grpc_slice_refcount *current_slice_refcount;
   /* the value we're currently parsing */
   union {
     uint32_t *value;
@@ -106,11 +114,9 @@ void grpc_chttp2_hpack_parser_destroy(grpc_exec_ctx *exec_ctx,
 
 void grpc_chttp2_hpack_parser_set_has_priority(grpc_chttp2_hpack_parser *p);
 
-/* returns 1 on success, 0 on error */
 grpc_error *grpc_chttp2_hpack_parser_parse(grpc_exec_ctx *exec_ctx,
                                            grpc_chttp2_hpack_parser *p,
-                                           const uint8_t *beg,
-                                           const uint8_t *end);
+                                           grpc_slice slice);
 
 /* wraps grpc_chttp2_hpack_parser_parse to provide a frame level parser for
    the transport */

src/core/ext/transport/chttp2/transport/hpack_table.c

@@ -190,8 +190,11 @@ void grpc_chttp2_hptbl_init(grpc_exec_ctx *exec_ctx, grpc_chttp2_hptbl *tbl) {
   tbl->ents = gpr_malloc(sizeof(*tbl->ents) * tbl->cap_entries);
   memset(tbl->ents, 0, sizeof(*tbl->ents) * tbl->cap_entries);
   for (i = 1; i <= GRPC_CHTTP2_LAST_STATIC_ENTRY; i++) {
-    tbl->static_ents[i - 1] = grpc_mdelem_from_strings(
-        exec_ctx, static_table[i].key, static_table[i].value);
+    tbl->static_ents[i - 1] = grpc_mdelem_from_slices(
+        exec_ctx,
+        grpc_slice_intern(grpc_slice_from_static_string(static_table[i].key)),
+        grpc_slice_intern(
+            grpc_slice_from_static_string(static_table[i].value)));
   }
 }
 
@@ -208,8 +211,8 @@ void grpc_chttp2_hptbl_destroy(grpc_exec_ctx *exec_ctx,
   gpr_free(tbl->ents);
 }
 
-grpc_mdelem *grpc_chttp2_hptbl_lookup(const grpc_chttp2_hptbl *tbl,
-                                      uint32_t tbl_index) {
+grpc_mdelem grpc_chttp2_hptbl_lookup(const grpc_chttp2_hptbl *tbl,
+                                     uint32_t tbl_index) {
   /* Static table comes first, just return an entry from it */
   if (tbl_index <= GRPC_CHTTP2_LAST_STATIC_ENTRY) {
     return tbl->static_ents[tbl_index - 1];
@@ -222,14 +225,14 @@ grpc_mdelem *grpc_chttp2_hptbl_lookup(const grpc_chttp2_hptbl *tbl,
     return tbl->ents[offset];
   }
   /* Invalid entry: return error */
-  return NULL;
+  return GRPC_MDNULL;
 }
 
 /* Evict one element from the table */
 static void evict1(grpc_exec_ctx *exec_ctx, grpc_chttp2_hptbl *tbl) {
-  grpc_mdelem *first_ent = tbl->ents[tbl->first_ent];
-  size_t elem_bytes = GRPC_SLICE_LENGTH(first_ent->key->slice) +
-                      GRPC_SLICE_LENGTH(first_ent->value->slice) +
+  grpc_mdelem first_ent = tbl->ents[tbl->first_ent];
+  size_t elem_bytes = GRPC_SLICE_LENGTH(GRPC_MDKEY(first_ent)) +
+                      GRPC_SLICE_LENGTH(GRPC_MDVALUE(first_ent)) +
                       GRPC_CHTTP2_HPACK_ENTRY_OVERHEAD;
   GPR_ASSERT(elem_bytes <= tbl->mem_used);
   tbl->mem_used -= (uint32_t)elem_bytes;
@@ -239,7 +242,7 @@ static void evict1(grpc_exec_ctx *exec_ctx, grpc_chttp2_hptbl *tbl) {
 }
 
 static void rebuild_ents(grpc_chttp2_hptbl *tbl, uint32_t new_cap) {
-  grpc_mdelem **ents = gpr_malloc(sizeof(*ents) * new_cap);
+  grpc_mdelem *ents = gpr_malloc(sizeof(*ents) * new_cap);
   uint32_t i;
 
   for (i = 0; i < tbl->num_ents; i++) {
@@ -301,10 +304,10 @@ grpc_error *grpc_chttp2_hptbl_set_current_table_size(grpc_exec_ctx *exec_ctx,
 }
 
 grpc_error *grpc_chttp2_hptbl_add(grpc_exec_ctx *exec_ctx,
-                                  grpc_chttp2_hptbl *tbl, grpc_mdelem *md) {
+                                  grpc_chttp2_hptbl *tbl, grpc_mdelem md) {
   /* determine how many bytes of buffer this entry represents */
-  size_t elem_bytes = GRPC_SLICE_LENGTH(md->key->slice) +
-                      GRPC_SLICE_LENGTH(md->value->slice) +
+  size_t elem_bytes = GRPC_SLICE_LENGTH(GRPC_MDKEY(md)) +
+                      GRPC_SLICE_LENGTH(GRPC_MDVALUE(md)) +
                       GRPC_CHTTP2_HPACK_ENTRY_OVERHEAD;
 
   if (tbl->current_table_bytes > tbl->max_bytes) {
@@ -352,16 +355,16 @@ grpc_error *grpc_chttp2_hptbl_add(grpc_exec_ctx *exec_ctx,
 }
 
 grpc_chttp2_hptbl_find_result grpc_chttp2_hptbl_find(
-    const grpc_chttp2_hptbl *tbl, grpc_mdelem *md) {
+    const grpc_chttp2_hptbl *tbl, grpc_mdelem md) {
   grpc_chttp2_hptbl_find_result r = {0, 0};
   uint32_t i;
 
   /* See if the string is in the static table */
   for (i = 0; i < GRPC_CHTTP2_LAST_STATIC_ENTRY; i++) {
-    grpc_mdelem *ent = tbl->static_ents[i];
-    if (md->key != ent->key) continue;
+    grpc_mdelem ent = tbl->static_ents[i];
+    if (!grpc_slice_eq(GRPC_MDKEY(md), GRPC_MDKEY(ent))) continue;
     r.index = i + 1u;
-    r.has_value = md->value == ent->value;
+    r.has_value = grpc_slice_eq(GRPC_MDVALUE(md), GRPC_MDVALUE(ent));
     if (r.has_value) return r;
   }
 
@@ -369,10 +372,10 @@ grpc_chttp2_hptbl_find_result grpc_chttp2_hptbl_find(
   for (i = 0; i < tbl->num_ents; i++) {
     uint32_t idx =
         (uint32_t)(tbl->num_ents - i + GRPC_CHTTP2_LAST_STATIC_ENTRY);
-    grpc_mdelem *ent = tbl->ents[(tbl->first_ent + i) % tbl->cap_entries];
-    if (md->key != ent->key) continue;
+    grpc_mdelem ent = tbl->ents[(tbl->first_ent + i) % tbl->cap_entries];
+    if (!grpc_slice_eq(GRPC_MDKEY(md), GRPC_MDKEY(ent))) continue;
     r.index = idx;
-    r.has_value = md->value == ent->value;
+    r.has_value = grpc_slice_eq(GRPC_MDVALUE(md), GRPC_MDVALUE(ent));
     if (r.has_value) return r;
   }
 

src/core/ext/transport/chttp2/transport/hpack_table.h

@@ -79,8 +79,8 @@ typedef struct {
   /* a circular buffer of headers - this is stored in the opposite order to
      what hpack specifies, in order to simplify table management a little...
      meaning lookups need to SUBTRACT from the end position */
-  grpc_mdelem **ents;
-  grpc_mdelem *static_ents[GRPC_CHTTP2_LAST_STATIC_ENTRY];
+  grpc_mdelem *ents;
+  grpc_mdelem static_ents[GRPC_CHTTP2_LAST_STATIC_ENTRY];
 } grpc_chttp2_hptbl;
 
 /* initialize a hpack table */
@@ -94,12 +94,12 @@ grpc_error *grpc_chttp2_hptbl_set_current_table_size(grpc_exec_ctx *exec_ctx,
                                                      uint32_t bytes);
 
 /* lookup a table entry based on its hpack index */
-grpc_mdelem *grpc_chttp2_hptbl_lookup(const grpc_chttp2_hptbl *tbl,
-                                      uint32_t index);
+grpc_mdelem grpc_chttp2_hptbl_lookup(const grpc_chttp2_hptbl *tbl,
+                                     uint32_t index);
 /* add a table entry to the index */
 grpc_error *grpc_chttp2_hptbl_add(grpc_exec_ctx *exec_ctx,
                                   grpc_chttp2_hptbl *tbl,
-                                  grpc_mdelem *md) GRPC_MUST_USE_RESULT;
+                                  grpc_mdelem md) GRPC_MUST_USE_RESULT;
 /* Find a key/value pair in the table... returns the index in the table of the
    most similar entry, or 0 if the value was not found */
 typedef struct {
@@ -107,6 +107,6 @@ typedef struct {
   int has_value;
 } grpc_chttp2_hptbl_find_result;
 grpc_chttp2_hptbl_find_result grpc_chttp2_hptbl_find(
-    const grpc_chttp2_hptbl *tbl, grpc_mdelem *md);
+    const grpc_chttp2_hptbl *tbl, grpc_mdelem md);
 
 #endif /* GRPC_CORE_EXT_TRANSPORT_CHTTP2_TRANSPORT_HPACK_TABLE_H */

src/core/ext/transport/chttp2/transport/incoming_metadata.c

@@ -57,7 +57,7 @@ void grpc_chttp2_incoming_metadata_buffer_destroy(
 }
 
 void grpc_chttp2_incoming_metadata_buffer_add(
-    grpc_chttp2_incoming_metadata_buffer *buffer, grpc_mdelem *elem) {
+    grpc_chttp2_incoming_metadata_buffer *buffer, grpc_mdelem elem) {
   GPR_ASSERT(!buffer->published);
   if (buffer->capacity == buffer->count) {
     buffer->capacity = GPR_MAX(8, 2 * buffer->capacity);
@@ -68,6 +68,19 @@ void grpc_chttp2_incoming_metadata_buffer_add(
   buffer->size += GRPC_MDELEM_LENGTH(elem);
 }
 
+void grpc_chttp2_incoming_metadata_buffer_replace_or_add(
+    grpc_exec_ctx *exec_ctx, grpc_chttp2_incoming_metadata_buffer *buffer,
+    grpc_mdelem elem) {
+  for (size_t i = 0; i < buffer->count; i++) {
+    if (grpc_slice_eq(GRPC_MDKEY(buffer->elems[i].md), GRPC_MDKEY(elem))) {
+      GRPC_MDELEM_UNREF(exec_ctx, buffer->elems[i].md);
+      buffer->elems[i].md = elem;
+      return;
+    }
+  }
+  grpc_chttp2_incoming_metadata_buffer_add(buffer, elem);
+}
+
 void grpc_chttp2_incoming_metadata_buffer_set_deadline(
     grpc_chttp2_incoming_metadata_buffer *buffer, gpr_timespec deadline) {
   GPR_ASSERT(!buffer->published);
@@ -75,21 +88,20 @@ void grpc_chttp2_incoming_metadata_buffer_set_deadline(
 }
 
 void grpc_chttp2_incoming_metadata_buffer_publish(
-    grpc_chttp2_incoming_metadata_buffer *buffer, grpc_metadata_batch *batch) {
+    grpc_exec_ctx *exec_ctx, grpc_chttp2_incoming_metadata_buffer *buffer,
+    grpc_metadata_batch *batch) {
   GPR_ASSERT(!buffer->published);
   buffer->published = 1;
   if (buffer->count > 0) {
     size_t i;
-    for (i = 1; i < buffer->count; i++) {
-      buffer->elems[i].prev = &buffer->elems[i - 1];
-    }
-    for (i = 0; i < buffer->count - 1; i++) {
-      buffer->elems[i].next = &buffer->elems[i + 1];
+    for (i = 0; i < buffer->count; i++) {
+      /* TODO(ctiller): do something better here */
+      if (!GRPC_LOG_IF_ERROR("grpc_chttp2_incoming_metadata_buffer_publish",
+                             grpc_metadata_batch_link_tail(
+                                 exec_ctx, batch, &buffer->elems[i]))) {
+        GRPC_MDELEM_UNREF(exec_ctx, buffer->elems[i].md);
+      }
     }
-    buffer->elems[0].prev = NULL;
-    buffer->elems[buffer->count - 1].next = NULL;
-    batch->list.head = &buffer->elems[0];
-    batch->list.tail = &buffer->elems[buffer->count - 1];
   } else {
     batch->list.head = batch->list.tail = NULL;
   }

src/core/ext/transport/chttp2/transport/incoming_metadata.h

@@ -51,10 +51,14 @@ void grpc_chttp2_incoming_metadata_buffer_init(
 void grpc_chttp2_incoming_metadata_buffer_destroy(
     grpc_exec_ctx *exec_ctx, grpc_chttp2_incoming_metadata_buffer *buffer);
 void grpc_chttp2_incoming_metadata_buffer_publish(
-    grpc_chttp2_incoming_metadata_buffer *buffer, grpc_metadata_batch *batch);
+    grpc_exec_ctx *exec_ctx, grpc_chttp2_incoming_metadata_buffer *buffer,
+    grpc_metadata_batch *batch);
 
 void grpc_chttp2_incoming_metadata_buffer_add(
-    grpc_chttp2_incoming_metadata_buffer *buffer, grpc_mdelem *elem);
+    grpc_chttp2_incoming_metadata_buffer *buffer, grpc_mdelem elem);
+void grpc_chttp2_incoming_metadata_buffer_replace_or_add(
+    grpc_exec_ctx *exec_ctx, grpc_chttp2_incoming_metadata_buffer *buffer,
+    grpc_mdelem elem);
 void grpc_chttp2_incoming_metadata_buffer_set_deadline(
     grpc_chttp2_incoming_metadata_buffer *buffer, gpr_timespec deadline);
 

src/core/ext/transport/chttp2/transport/internal.h

@@ -618,8 +618,7 @@ void grpc_chttp2_flowctl_trace(const char *file, int line, const char *phase,
                                uint32_t stream_id, int64_t val1, int64_t val2);
 
 void grpc_chttp2_fake_status(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
-                             grpc_chttp2_stream *stream,
-                             grpc_status_code status, grpc_slice *details);
+                             grpc_chttp2_stream *stream, grpc_error *error);
 void grpc_chttp2_mark_stream_closed(grpc_exec_ctx *exec_ctx,
                                     grpc_chttp2_transport *t,
                                     grpc_chttp2_stream *s, int close_reads,

src/core/ext/transport/chttp2/transport/parsing.c

@@ -39,10 +39,11 @@
 #include <grpc/support/log.h>
 #include <grpc/support/string_util.h>
 
-#include "src/core/ext/transport/chttp2/transport/http2_errors.h"
-#include "src/core/ext/transport/chttp2/transport/status_conversion.h"
 #include "src/core/lib/profiling/timers.h"
+#include "src/core/lib/slice/slice_string_helpers.h"
+#include "src/core/lib/transport/http2_errors.h"
 #include "src/core/lib/transport/static_metadata.h"
+#include "src/core/lib/transport/status_conversion.h"
 #include "src/core/lib/transport/timeout_encoding.h"
 
 static grpc_error *init_frame_parser(grpc_exec_ctx *exec_ctx,
@@ -200,7 +201,7 @@ grpc_error *grpc_chttp2_perform_read(grpc_exec_ctx *exec_ctx,
         return err;
       }
       if (t->incoming_frame_size == 0) {
-        err = parse_frame_slice(exec_ctx, t, gpr_empty_slice(), 1);
+        err = parse_frame_slice(exec_ctx, t, grpc_empty_slice(), 1);
         if (err != GRPC_ERROR_NONE) {
           return err;
         }
@@ -335,7 +336,7 @@ static grpc_error *skip_parser(grpc_exec_ctx *exec_ctx, void *parser,
   return GRPC_ERROR_NONE;
 }
 
-static void skip_header(grpc_exec_ctx *exec_ctx, void *tp, grpc_mdelem *md) {
+static void skip_header(grpc_exec_ctx *exec_ctx, void *tp, grpc_mdelem md) {
   GRPC_MDELEM_UNREF(exec_ctx, md);
 }
 
@@ -432,7 +433,7 @@ error_handler:
     }
     grpc_slice_buffer_add(
         &t->qbuf, grpc_chttp2_rst_stream_create(t->incoming_stream_id,
-                                                GRPC_CHTTP2_PROTOCOL_ERROR,
+                                                GRPC_HTTP2_PROTOCOL_ERROR,
                                                 &s->stats.outgoing));
     return init_skip_frame_parser(exec_ctx, t, 0);
   } else {
@@ -443,7 +444,7 @@ error_handler:
 static void free_timeout(void *p) { gpr_free(p); }
 
 static void on_initial_header(grpc_exec_ctx *exec_ctx, void *tp,
-                              grpc_mdelem *md) {
+                              grpc_mdelem md) {
   grpc_chttp2_transport *t = tp;
   grpc_chttp2_stream *s = t->incoming_stream;
 
@@ -451,32 +452,42 @@ static void on_initial_header(grpc_exec_ctx *exec_ctx, void *tp,
 
   GPR_ASSERT(s != NULL);
 
-  GRPC_CHTTP2_IF_TRACING(gpr_log(
-      GPR_INFO, "HTTP:%d:HDR:%s: %s: %s", s->id, t->is_client ? "CLI" : "SVR",
-      grpc_mdstr_as_c_string(md->key), grpc_mdstr_as_c_string(md->value)));
+  if (grpc_http_trace) {
+    char *key = grpc_slice_to_c_string(GRPC_MDKEY(md));
+    char *value =
+        grpc_dump_slice(GRPC_MDVALUE(md), GPR_DUMP_HEX | GPR_DUMP_ASCII);
+    gpr_log(GPR_INFO, "HTTP:%d:HDR:%s: %s: %s", s->id,
+            t->is_client ? "CLI" : "SVR", key, value);
+    gpr_free(key);
+    gpr_free(value);
+  }
 
-  if (md->key == GRPC_MDSTR_GRPC_STATUS && md != GRPC_MDELEM_GRPC_STATUS_0) {
+  if (grpc_slice_eq(GRPC_MDKEY(md), GRPC_MDSTR_GRPC_STATUS) &&
+      !grpc_mdelem_eq(md, GRPC_MDELEM_GRPC_STATUS_0)) {
     /* TODO(ctiller): check for a status like " 0" */
     s->seen_error = true;
   }
 
-  if (md->key == GRPC_MDSTR_GRPC_TIMEOUT) {
+  if (grpc_slice_eq(GRPC_MDKEY(md), GRPC_MDSTR_GRPC_TIMEOUT)) {
     gpr_timespec *cached_timeout = grpc_mdelem_get_user_data(md, free_timeout);
-    if (!cached_timeout) {
+    gpr_timespec timeout;
+    if (cached_timeout == NULL) {
       /* not already parsed: parse it now, and store the result away */
       cached_timeout = gpr_malloc(sizeof(gpr_timespec));
-      if (!grpc_http2_decode_timeout(grpc_mdstr_as_c_string(md->value),
-                                     cached_timeout)) {
-        gpr_log(GPR_ERROR, "Ignoring bad timeout value '%s'",
-                grpc_mdstr_as_c_string(md->value));
+      if (!grpc_http2_decode_timeout(GRPC_MDVALUE(md), cached_timeout)) {
+        char *val = grpc_slice_to_c_string(GRPC_MDVALUE(md));
+        gpr_log(GPR_ERROR, "Ignoring bad timeout value '%s'", val);
+        gpr_free(val);
         *cached_timeout = gpr_inf_future(GPR_TIMESPAN);
       }
-      cached_timeout =
-          grpc_mdelem_set_user_data(md, free_timeout, cached_timeout);
+      timeout = *cached_timeout;
+      grpc_mdelem_set_user_data(md, free_timeout, cached_timeout);
+    } else {
+      timeout = *cached_timeout;
     }
     grpc_chttp2_incoming_metadata_buffer_set_deadline(
         &s->metadata_buffer[0],
-        gpr_time_add(gpr_now(GPR_CLOCK_MONOTONIC), *cached_timeout));
+        gpr_time_add(gpr_now(GPR_CLOCK_MONOTONIC), timeout));
     GRPC_MDELEM_UNREF(exec_ctx, md);
   } else {
     const size_t new_size = s->metadata_buffer[0].size + GRPC_MDELEM_LENGTH(md);
@@ -505,7 +516,7 @@ static void on_initial_header(grpc_exec_ctx *exec_ctx, void *tp,
 }
 
 static void on_trailing_header(grpc_exec_ctx *exec_ctx, void *tp,
-                               grpc_mdelem *md) {
+                               grpc_mdelem md) {
   grpc_chttp2_transport *t = tp;
   grpc_chttp2_stream *s = t->incoming_stream;
 
@@ -513,11 +524,18 @@ static void on_trailing_header(grpc_exec_ctx *exec_ctx, void *tp,
 
   GPR_ASSERT(s != NULL);
 
-  GRPC_CHTTP2_IF_TRACING(gpr_log(
-      GPR_INFO, "HTTP:%d:TRL:%s: %s: %s", s->id, t->is_client ? "CLI" : "SVR",
-      grpc_mdstr_as_c_string(md->key), grpc_mdstr_as_c_string(md->value)));
+  if (grpc_http_trace) {
+    char *key = grpc_slice_to_c_string(GRPC_MDKEY(md));
+    char *value =
+        grpc_dump_slice(GRPC_MDVALUE(md), GPR_DUMP_HEX | GPR_DUMP_ASCII);
+    gpr_log(GPR_INFO, "HTTP:%d:TRL:%s: %s: %s", s->id,
+            t->is_client ? "CLI" : "SVR", key, value);
+    gpr_free(key);
+    gpr_free(value);
+  }
 
-  if (md->key == GRPC_MDSTR_GRPC_STATUS && md != GRPC_MDELEM_GRPC_STATUS_0) {
+  if (grpc_slice_eq(GRPC_MDKEY(md), GRPC_MDSTR_GRPC_STATUS) &&
+      !grpc_mdelem_eq(md, GRPC_MDELEM_GRPC_STATUS_0)) {
     /* TODO(ctiller): check for a status like " 0" */
     s->seen_error = true;
   }
@@ -733,14 +751,13 @@ static grpc_error *parse_frame_slice(grpc_exec_ctx *exec_ctx,
     if (grpc_http_trace) {
       const char *msg = grpc_error_string(err);
       gpr_log(GPR_ERROR, "%s", msg);
-      grpc_error_free_string(msg);
     }
     grpc_chttp2_parsing_become_skip_parser(exec_ctx, t);
     if (s) {
       s->forced_close_error = err;
       grpc_slice_buffer_add(
           &t->qbuf, grpc_chttp2_rst_stream_create(t->incoming_stream_id,
-                                                  GRPC_CHTTP2_PROTOCOL_ERROR,
+                                                  GRPC_HTTP2_PROTOCOL_ERROR,
                                                   &s->stats.outgoing));
     } else {
       GRPC_ERROR_UNREF(err);

src/core/ext/transport/chttp2/transport/writing.c

@@ -37,9 +37,9 @@
 
 #include <grpc/support/log.h>
 
-#include "src/core/ext/transport/chttp2/transport/http2_errors.h"
 #include "src/core/lib/profiling/timers.h"
 #include "src/core/lib/slice/slice_internal.h"
+#include "src/core/lib/transport/http2_errors.h"
 
 static void add_to_write_list(grpc_chttp2_write_cb **list,
                               grpc_chttp2_write_cb *cb) {
@@ -164,7 +164,7 @@ bool grpc_chttp2_begin_write(grpc_exec_ctx *exec_ctx,
             s->sent_trailing_metadata = true;
             if (!t->is_client && !s->read_closed) {
               grpc_slice_buffer_add(&t->outbuf, grpc_chttp2_rst_stream_create(
-                                                    s->id, GRPC_CHTTP2_NO_ERROR,
+                                                    s->id, GRPC_HTTP2_NO_ERROR,
                                                     &s->stats.outgoing));
             }
           }
@@ -197,7 +197,7 @@ bool grpc_chttp2_begin_write(grpc_exec_ctx *exec_ctx,
         if (!t->is_client && !s->read_closed) {
           grpc_slice_buffer_add(
               &t->outbuf, grpc_chttp2_rst_stream_create(
-                              s->id, GRPC_CHTTP2_NO_ERROR, &s->stats.outgoing));
+                              s->id, GRPC_HTTP2_NO_ERROR, &s->stats.outgoing));
         }
         now_writing = true;
       }

src/core/ext/transport/cronet/transport/cronet_transport.c

@@ -44,6 +44,8 @@
 #include "src/core/ext/transport/chttp2/transport/incoming_metadata.h"
 #include "src/core/lib/iomgr/endpoint.h"
 #include "src/core/lib/iomgr/exec_ctx.h"
+#include "src/core/lib/slice/slice_internal.h"
+#include "src/core/lib/slice/slice_string_helpers.h"
 #include "src/core/lib/support/string.h"
 #include "src/core/lib/surface/channel.h"
 #include "src/core/lib/transport/metadata_batch.h"
@@ -437,9 +439,11 @@ static void on_response_headers_received(
   for (size_t i = 0; i < headers->count; i++) {
     grpc_chttp2_incoming_metadata_buffer_add(
         &s->state.rs.initial_metadata,
-        grpc_mdelem_from_metadata_strings(
-            &exec_ctx, grpc_mdstr_from_string(headers->headers[i].key),
-            grpc_mdstr_from_string(headers->headers[i].value)));
+        grpc_mdelem_from_slices(
+            &exec_ctx, grpc_slice_intern(grpc_slice_from_static_string(
+                           headers->headers[i].key)),
+            grpc_slice_intern(
+                grpc_slice_from_static_string(headers->headers[i].value))));
   }
   s->state.state_callback_received[OP_RECV_INITIAL_METADATA] = true;
   if (!(s->state.state_op_done[OP_CANCEL_ERROR] ||
@@ -534,9 +538,11 @@ static void on_response_trailers_received(
                trailers->headers[i].value);
     grpc_chttp2_incoming_metadata_buffer_add(
         &s->state.rs.trailing_metadata,
-        grpc_mdelem_from_metadata_strings(
-            &exec_ctx, grpc_mdstr_from_string(trailers->headers[i].key),
-            grpc_mdstr_from_string(trailers->headers[i].value)));
+        grpc_mdelem_from_slices(
+            &exec_ctx, grpc_slice_intern(grpc_slice_from_static_string(
+                           trailers->headers[i].key)),
+            grpc_slice_intern(
+                grpc_slice_from_static_string(trailers->headers[i].value))));
     s->state.rs.trailing_metadata_valid = true;
     if (0 == strcmp(trailers->headers[i].key, "grpc-status") &&
         0 != strcmp(trailers->headers[i].value, "0")) {
@@ -616,33 +622,41 @@ static void convert_metadata_to_cronet_headers(
   curr = head;
   size_t num_headers = 0;
   while (num_headers < num_headers_available) {
-    grpc_mdelem *mdelem = curr->md;
+    grpc_mdelem mdelem = curr->md;
     curr = curr->next;
-    const char *key = grpc_mdstr_as_c_string(mdelem->key);
-    const char *value = grpc_mdstr_as_c_string(mdelem->value);
-    if (mdelem->key == GRPC_MDSTR_SCHEME ||
-        mdelem->key == GRPC_MDSTR_AUTHORITY) {
+    char *key = grpc_slice_to_c_string(GRPC_MDKEY(mdelem));
+    char *value = grpc_slice_to_c_string(GRPC_MDVALUE(mdelem));
+    if (grpc_slice_eq(GRPC_MDKEY(mdelem), GRPC_MDSTR_SCHEME) ||
+        grpc_slice_eq(GRPC_MDKEY(mdelem), GRPC_MDSTR_AUTHORITY)) {
       /* Cronet populates these fields on its own */
+      gpr_free(key);
+      gpr_free(value);
       continue;
     }
-    if (mdelem->key == GRPC_MDSTR_METHOD) {
-      if (mdelem->value == GRPC_MDSTR_PUT) {
+    if (grpc_slice_eq(GRPC_MDKEY(mdelem), GRPC_MDSTR_METHOD)) {
+      if (grpc_slice_eq(GRPC_MDVALUE(mdelem), GRPC_MDSTR_PUT)) {
         *method = "PUT";
       } else {
         /* POST method in default*/
         *method = "POST";
       }
+      gpr_free(key);
+      gpr_free(value);
       continue;
     }
-    if (mdelem->key == GRPC_MDSTR_PATH) {
+    if (grpc_slice_eq(GRPC_MDKEY(mdelem), GRPC_MDSTR_PATH)) {
       /* Create URL by appending :path value to the hostname */
       gpr_asprintf(pp_url, "https://%s%s", host, value);
+      gpr_free(key);
+      gpr_free(value);
       continue;
     }
     CRONET_LOG(GPR_DEBUG, "header %s = %s", key, value);
     headers[num_headers].key = key;
     headers[num_headers].value = value;
     num_headers++;
+    gpr_free(key);
+    gpr_free(value);
     if (curr == NULL) {
       break;
     }
@@ -662,7 +676,7 @@ static int parse_grpc_header(const uint8_t *data) {
 
 static bool header_has_authority(grpc_linked_mdelem *head) {
   while (head != NULL) {
-    if (head->md->key == GRPC_MDSTR_AUTHORITY) {
+    if (grpc_slice_eq(GRPC_MDKEY(head->md), GRPC_MDSTR_AUTHORITY)) {
       return true;
     }
     head = head->next;
@@ -858,7 +872,8 @@ static enum e_op_result execute_stream_op(grpc_exec_ctx *exec_ctx,
           make_error_with_desc(GRPC_STATUS_UNAVAILABLE, "Unavailable."));
     } else {
       grpc_chttp2_incoming_metadata_buffer_publish(
-          &oas->s->state.rs.initial_metadata, stream_op->recv_initial_metadata);
+          exec_ctx, &oas->s->state.rs.initial_metadata,
+          stream_op->recv_initial_metadata);
       grpc_closure_sched(exec_ctx, stream_op->recv_initial_metadata_ready,
                          GRPC_ERROR_NONE);
     }
@@ -1015,7 +1030,7 @@ static enum e_op_result execute_stream_op(grpc_exec_ctx *exec_ctx,
     CRONET_LOG(GPR_DEBUG, "running: %p  OP_RECV_TRAILING_METADATA", oas);
     if (oas->s->state.rs.trailing_metadata_valid) {
       grpc_chttp2_incoming_metadata_buffer_publish(
-          &oas->s->state.rs.trailing_metadata,
+          exec_ctx, &oas->s->state.rs.trailing_metadata,
           stream_op->recv_trailing_metadata);
       stream_state->rs.trailing_metadata_valid = false;
     }

src/core/lib/channel/channel_stack.c

@@ -170,7 +170,7 @@ grpc_error *grpc_call_stack_init(
     grpc_exec_ctx *exec_ctx, grpc_channel_stack *channel_stack,
     int initial_refs, grpc_iomgr_cb_func destroy, void *destroy_arg,
     grpc_call_context_element *context, const void *transport_server_data,
-    grpc_mdstr *path, gpr_timespec start_time, gpr_timespec deadline,
+    grpc_slice path, gpr_timespec start_time, gpr_timespec deadline,
     grpc_call_stack *call_stack) {
   grpc_channel_element *channel_elems = CHANNEL_ELEMS_FROM_STACK(channel_stack);
   grpc_call_element_args args;
@@ -288,41 +288,10 @@ grpc_call_stack *grpc_call_stack_from_top_element(grpc_call_element *elem) {
       sizeof(grpc_call_stack)));
 }
 
-static void destroy_op(grpc_exec_ctx *exec_ctx, void *op, grpc_error *error) {
-  gpr_free(op);
-}
-
-void grpc_call_element_send_cancel(grpc_exec_ctx *exec_ctx,
-                                   grpc_call_element *elem) {
-  grpc_transport_stream_op *op = gpr_malloc(sizeof(*op));
-  memset(op, 0, sizeof(*op));
-  op->cancel_error = GRPC_ERROR_CANCELLED;
-  op->on_complete =
-      grpc_closure_create(destroy_op, op, grpc_schedule_on_exec_ctx);
-  elem->filter->start_transport_stream_op(exec_ctx, elem, op);
-}
-
-void grpc_call_element_send_cancel_with_message(grpc_exec_ctx *exec_ctx,
-                                                grpc_call_element *elem,
-                                                grpc_status_code status,
-                                                grpc_slice *optional_message) {
-  grpc_transport_stream_op *op = gpr_malloc(sizeof(*op));
-  memset(op, 0, sizeof(*op));
-  op->on_complete =
-      grpc_closure_create(destroy_op, op, grpc_schedule_on_exec_ctx);
-  grpc_transport_stream_op_add_cancellation_with_message(exec_ctx, op, status,
-                                                         optional_message);
-  elem->filter->start_transport_stream_op(exec_ctx, elem, op);
-}
-
-void grpc_call_element_send_close_with_message(grpc_exec_ctx *exec_ctx,
-                                               grpc_call_element *elem,
-                                               grpc_status_code status,
-                                               grpc_slice *optional_message) {
-  grpc_transport_stream_op *op = gpr_malloc(sizeof(*op));
-  memset(op, 0, sizeof(*op));
-  op->on_complete =
-      grpc_closure_create(destroy_op, op, grpc_schedule_on_exec_ctx);
-  grpc_transport_stream_op_add_close(exec_ctx, op, status, optional_message);
+void grpc_call_element_signal_error(grpc_exec_ctx *exec_ctx,
+                                    grpc_call_element *elem,
+                                    grpc_error *error) {
+  grpc_transport_stream_op *op = grpc_make_transport_stream_op(NULL);
+  op->cancel_error = error;
   elem->filter->start_transport_stream_op(exec_ctx, elem, op);
 }

src/core/lib/channel/channel_stack.h

@@ -81,7 +81,7 @@ typedef struct {
   grpc_call_stack *call_stack;
   const void *server_transport_data;
   grpc_call_context_element *context;
-  grpc_mdstr *path;
+  grpc_slice path;
   gpr_timespec start_time;
   gpr_timespec deadline;
 } grpc_call_element_args;
@@ -238,7 +238,7 @@ grpc_error *grpc_call_stack_init(
     grpc_exec_ctx *exec_ctx, grpc_channel_stack *channel_stack,
     int initial_refs, grpc_iomgr_cb_func destroy, void *destroy_arg,
     grpc_call_context_element *context, const void *transport_server_data,
-    grpc_mdstr *path, gpr_timespec start_time, gpr_timespec deadline,
+    grpc_slice path, gpr_timespec start_time, gpr_timespec deadline,
     grpc_call_stack *call_stack);
 /* Set a pollset or a pollset_set for a call stack: must occur before the first
  * op is started */
@@ -299,18 +299,9 @@ grpc_call_stack *grpc_call_stack_from_top_element(grpc_call_element *elem);
 void grpc_call_log_op(char *file, int line, gpr_log_severity severity,
                       grpc_call_element *elem, grpc_transport_stream_op *op);
 
-void grpc_call_element_send_cancel(grpc_exec_ctx *exec_ctx,
-                                   grpc_call_element *cur_elem);
-
-void grpc_call_element_send_cancel_with_message(grpc_exec_ctx *exec_ctx,
-                                                grpc_call_element *cur_elem,
-                                                grpc_status_code status,
-                                                grpc_slice *optional_message);
-
-void grpc_call_element_send_close_with_message(grpc_exec_ctx *exec_ctx,
-                                               grpc_call_element *cur_elem,
-                                               grpc_status_code status,
-                                               grpc_slice *optional_message);
+void grpc_call_element_signal_error(grpc_exec_ctx *exec_ctx,
+                                    grpc_call_element *cur_elem,
+                                    grpc_error *error);
 
 extern int grpc_trace_channel;
 

src/core/lib/channel/compress_filter.c

@@ -45,6 +45,7 @@
 #include "src/core/lib/compression/message_compress.h"
 #include "src/core/lib/profiling/timers.h"
 #include "src/core/lib/slice/slice_internal.h"
+#include "src/core/lib/slice/slice_string_helpers.h"
 #include "src/core/lib/support/string.h"
 #include "src/core/lib/transport/static_metadata.h"
 
@@ -80,39 +81,6 @@ typedef struct channel_data {
   uint32_t supported_compression_algorithms;
 } channel_data;
 
-/** For each \a md element from the incoming metadata, filter out the entry for
- * "grpc-encoding", using its value to populate the call data's
- * compression_algorithm field. */
-static grpc_mdelem *compression_md_filter(grpc_exec_ctx *exec_ctx,
-                                          void *user_data, grpc_mdelem *md) {
-  grpc_call_element *elem = user_data;
-  call_data *calld = elem->call_data;
-  channel_data *channeld = elem->channel_data;
-
-  if (md->key == GRPC_MDSTR_GRPC_INTERNAL_ENCODING_REQUEST) {
-    const char *md_c_str = grpc_mdstr_as_c_string(md->value);
-    if (!grpc_compression_algorithm_parse(md_c_str, strlen(md_c_str),
-                                          &calld->compression_algorithm)) {
-      gpr_log(GPR_ERROR,
-              "Invalid compression algorithm: '%s' (unknown). Ignoring.",
-              md_c_str);
-      calld->compression_algorithm = GRPC_COMPRESS_NONE;
-    }
-    if (!GPR_BITGET(channeld->enabled_algorithms_bitset,
-                    calld->compression_algorithm)) {
-      gpr_log(GPR_ERROR,
-              "Invalid compression algorithm: '%s' (previously disabled). "
-              "Ignoring.",
-              md_c_str);
-      calld->compression_algorithm = GRPC_COMPRESS_NONE;
-    }
-    calld->has_compression_algorithm = 1;
-    return NULL;
-  }
-
-  return md;
-}
-
 static int skip_compression(grpc_call_element *elem, uint32_t flags) {
   call_data *calld = elem->call_data;
   channel_data *channeld = elem->channel_data;
@@ -131,32 +99,65 @@ static int skip_compression(grpc_call_element *elem, uint32_t flags) {
 }
 
 /** Filter initial metadata */
-static void process_send_initial_metadata(
+static grpc_error *process_send_initial_metadata(
+    grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
+    grpc_metadata_batch *initial_metadata) GRPC_MUST_USE_RESULT;
+static grpc_error *process_send_initial_metadata(
     grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
     grpc_metadata_batch *initial_metadata) {
+  grpc_error *error;
   call_data *calld = elem->call_data;
   channel_data *channeld = elem->channel_data;
   /* Parse incoming request for compression. If any, it'll be available
    * at calld->compression_algorithm */
-  grpc_metadata_batch_filter(exec_ctx, initial_metadata, compression_md_filter,
-                             elem);
-  if (!calld->has_compression_algorithm) {
+  if (initial_metadata->idx.named.grpc_internal_encoding_request != NULL) {
+    grpc_mdelem md =
+        initial_metadata->idx.named.grpc_internal_encoding_request->md;
+    if (!grpc_compression_algorithm_parse(GRPC_MDVALUE(md),
+                                          &calld->compression_algorithm)) {
+      char *val = grpc_slice_to_c_string(GRPC_MDVALUE(md));
+      gpr_log(GPR_ERROR,
+              "Invalid compression algorithm: '%s' (unknown). Ignoring.", val);
+      gpr_free(val);
+      calld->compression_algorithm = GRPC_COMPRESS_NONE;
+    }
+    if (!GPR_BITGET(channeld->enabled_algorithms_bitset,
+                    calld->compression_algorithm)) {
+      char *val = grpc_slice_to_c_string(GRPC_MDVALUE(md));
+      gpr_log(GPR_ERROR,
+              "Invalid compression algorithm: '%s' (previously disabled). "
+              "Ignoring.",
+              val);
+      gpr_free(val);
+      calld->compression_algorithm = GRPC_COMPRESS_NONE;
+    }
+    calld->has_compression_algorithm = 1;
+
+    grpc_metadata_batch_remove(
+        exec_ctx, initial_metadata,
+        initial_metadata->idx.named.grpc_internal_encoding_request);
+  } else {
     /* If no algorithm was found in the metadata and we aren't
      * exceptionally skipping compression, fall back to the channel
      * default */
     calld->compression_algorithm = channeld->default_compression_algorithm;
     calld->has_compression_algorithm = 1; /* GPR_TRUE */
   }
+
   /* hint compression algorithm */
-  grpc_metadata_batch_add_tail(
-      initial_metadata, &calld->compression_algorithm_storage,
+  error = grpc_metadata_batch_add_tail(
+      exec_ctx, initial_metadata, &calld->compression_algorithm_storage,
       grpc_compression_encoding_mdelem(calld->compression_algorithm));
 
+  if (error != GRPC_ERROR_NONE) return error;
+
   /* convey supported compression algorithms */
-  grpc_metadata_batch_add_tail(initial_metadata,
-                               &calld->accept_encoding_storage,
-                               GRPC_MDELEM_ACCEPT_ENCODING_FOR_ALGORITHMS(
-                                   channeld->supported_compression_algorithms));
+  error = grpc_metadata_batch_add_tail(
+      exec_ctx, initial_metadata, &calld->accept_encoding_storage,
+      GRPC_MDELEM_ACCEPT_ENCODING_FOR_ALGORITHMS(
+          channeld->supported_compression_algorithms));
+
+  return error;
 }
 
 static void continue_send_message(grpc_exec_ctx *exec_ctx,
@@ -247,7 +248,12 @@ static void compress_start_transport_stream_op(grpc_exec_ctx *exec_ctx,
   GPR_TIMER_BEGIN("compress_start_transport_stream_op", 0);
 
   if (op->send_initial_metadata) {
-    process_send_initial_metadata(exec_ctx, elem, op->send_initial_metadata);
+    grpc_error *error = process_send_initial_metadata(
+        exec_ctx, elem, op->send_initial_metadata);
+    if (error != GRPC_ERROR_NONE) {
+      grpc_transport_stream_op_finish_with_failure(exec_ctx, op, error);
+      return;
+    }
   }
   if (op->send_message != NULL &&
       !skip_compression(elem, op->send_message->flags)) {

src/core/lib/channel/deadline_filter.c

@@ -56,10 +56,11 @@ static void timer_callback(grpc_exec_ctx* exec_ctx, void* arg,
   deadline_state->timer_pending = false;
   gpr_mu_unlock(&deadline_state->timer_mu);
   if (error != GRPC_ERROR_CANCELLED) {
-    grpc_slice msg = grpc_slice_from_static_string("Deadline Exceeded");
-    grpc_call_element_send_cancel_with_message(
-        exec_ctx, elem, GRPC_STATUS_DEADLINE_EXCEEDED, &msg);
-    grpc_slice_unref_internal(exec_ctx, msg);
+    grpc_call_element_signal_error(
+        exec_ctx, elem,
+        grpc_error_set_int(GRPC_ERROR_CREATE("Deadline Exceeded"),
+                           GRPC_ERROR_INT_GRPC_STATUS,
+                           GRPC_STATUS_DEADLINE_EXCEEDED));
   }
   GRPC_CALL_STACK_UNREF(exec_ctx, deadline_state->call_stack, "deadline_timer");
 }
@@ -196,8 +197,7 @@ void grpc_deadline_state_client_start_transport_stream_op(
     grpc_exec_ctx* exec_ctx, grpc_call_element* elem,
     grpc_transport_stream_op* op) {
   grpc_deadline_state* deadline_state = elem->call_data;
-  if (op->cancel_error != GRPC_ERROR_NONE ||
-      op->close_error != GRPC_ERROR_NONE) {
+  if (op->cancel_error != GRPC_ERROR_NONE) {
     cancel_timer_if_needed(exec_ctx, deadline_state);
   } else {
     // Make sure we know when the call is complete, so that we can cancel
@@ -285,8 +285,7 @@ static void server_start_transport_stream_op(grpc_exec_ctx* exec_ctx,
                                              grpc_call_element* elem,
                                              grpc_transport_stream_op* op) {
   server_call_data* calld = elem->call_data;
-  if (op->cancel_error != GRPC_ERROR_NONE ||
-      op->close_error != GRPC_ERROR_NONE) {
+  if (op->cancel_error != GRPC_ERROR_NONE) {
     cancel_timer_if_needed(exec_ctx, &calld->base.deadline_state);
   } else {
     // If we're receiving initial metadata, we need to get the deadline

src/core/lib/channel/http_client_filter.c

@@ -38,6 +38,7 @@
 #include "src/core/lib/profiling/timers.h"
 #include "src/core/lib/slice/percent_encoding.h"
 #include "src/core/lib/slice/slice_internal.h"
+#include "src/core/lib/slice/slice_string_helpers.h"
 #include "src/core/lib/support/string.h"
 #include "src/core/lib/transport/static_metadata.h"
 #include "src/core/lib/transport/transport_impl.h"
@@ -88,77 +89,104 @@ typedef struct call_data {
 } call_data;
 
 typedef struct channel_data {
-  grpc_mdelem *static_scheme;
-  grpc_mdelem *user_agent;
+  grpc_mdelem static_scheme;
+  grpc_mdelem user_agent;
   size_t max_payload_size_for_get;
 } channel_data;
 
-static grpc_mdelem *client_recv_filter(grpc_exec_ctx *exec_ctx, void *user_data,
-                                       grpc_mdelem *md) {
-  grpc_call_element *elem = user_data;
-  if (md == GRPC_MDELEM_STATUS_200) {
-    return NULL;
-  } else if (md->key == GRPC_MDSTR_STATUS) {
-    char *message_string;
-    gpr_asprintf(&message_string, "Received http2 header with status: %s",
-                 grpc_mdstr_as_c_string(md->value));
-    grpc_slice message = grpc_slice_from_copied_string(message_string);
-    gpr_free(message_string);
-    grpc_call_element_send_close_with_message(exec_ctx, elem,
-                                              GRPC_STATUS_CANCELLED, &message);
-    return NULL;
-  } else if (md->key == GRPC_MDSTR_GRPC_MESSAGE) {
-    grpc_slice pct_decoded_msg =
-        grpc_permissive_percent_decode_slice(md->value->slice);
-    if (grpc_slice_is_equivalent(pct_decoded_msg, md->value->slice)) {
-      grpc_slice_unref_internal(exec_ctx, pct_decoded_msg);
-      return md;
+static grpc_error *client_filter_incoming_metadata(grpc_exec_ctx *exec_ctx,
+                                                   grpc_call_element *elem,
+                                                   grpc_metadata_batch *b) {
+  if (b->idx.named.status != NULL) {
+    if (grpc_mdelem_eq(b->idx.named.status->md, GRPC_MDELEM_STATUS_200)) {
+      grpc_metadata_batch_remove(exec_ctx, b, b->idx.named.status);
     } else {
-      return grpc_mdelem_from_metadata_strings(
-          exec_ctx, GRPC_MDSTR_GRPC_MESSAGE,
-          grpc_mdstr_from_slice(exec_ctx, pct_decoded_msg));
+      char *val = grpc_dump_slice(GRPC_MDVALUE(b->idx.named.status->md),
+                                  GPR_DUMP_ASCII);
+      char *msg;
+      gpr_asprintf(&msg, "Received http2 header with status: %s", val);
+      grpc_error *e = grpc_error_set_str(
+          grpc_error_set_int(
+              grpc_error_set_str(
+                  GRPC_ERROR_CREATE(
+                      "Received http2 :status header with non-200 OK status"),
+                  GRPC_ERROR_STR_VALUE, val),
+              GRPC_ERROR_INT_GRPC_STATUS, GRPC_STATUS_CANCELLED),
+          GRPC_ERROR_STR_GRPC_MESSAGE, msg);
+      gpr_free(val);
+      gpr_free(msg);
+      return e;
     }
-  } else if (md == GRPC_MDELEM_CONTENT_TYPE_APPLICATION_SLASH_GRPC) {
-    return NULL;
-  } else if (md->key == GRPC_MDSTR_CONTENT_TYPE) {
-    const char *value_str = grpc_mdstr_as_c_string(md->value);
-    if (strncmp(value_str, EXPECTED_CONTENT_TYPE,
-                EXPECTED_CONTENT_TYPE_LENGTH) == 0 &&
-        (value_str[EXPECTED_CONTENT_TYPE_LENGTH] == '+' ||
-         value_str[EXPECTED_CONTENT_TYPE_LENGTH] == ';')) {
-      /* Although the C implementation doesn't (currently) generate them,
-         any custom +-suffix is explicitly valid. */
-      /* TODO(klempner): We should consider preallocating common values such
-         as +proto or +json, or at least stashing them if we see them. */
-      /* TODO(klempner): Should we be surfacing this to application code? */
+  }
+
+  if (b->idx.named.grpc_message != NULL) {
+    grpc_slice pct_decoded_msg = grpc_permissive_percent_decode_slice(
+        GRPC_MDVALUE(b->idx.named.grpc_message->md));
+    if (grpc_slice_is_equivalent(pct_decoded_msg,
+                                 GRPC_MDVALUE(b->idx.named.grpc_message->md))) {
+      grpc_slice_unref_internal(exec_ctx, pct_decoded_msg);
     } else {
-      /* TODO(klempner): We're currently allowing this, but we shouldn't
-         see it without a proxy so log for now. */
-      gpr_log(GPR_INFO, "Unexpected content-type '%s'", value_str);
+      grpc_metadata_batch_set_value(exec_ctx, b->idx.named.grpc_message,
+                                    pct_decoded_msg);
     }
-    return NULL;
   }
-  return md;
+
+  if (b->idx.named.content_type != NULL) {
+    if (!grpc_mdelem_eq(b->idx.named.content_type->md,
+                        GRPC_MDELEM_CONTENT_TYPE_APPLICATION_SLASH_GRPC)) {
+      if (grpc_slice_buf_start_eq(GRPC_MDVALUE(b->idx.named.content_type->md),
+                                  EXPECTED_CONTENT_TYPE,
+                                  EXPECTED_CONTENT_TYPE_LENGTH) &&
+          (GRPC_SLICE_START_PTR(GRPC_MDVALUE(
+               b->idx.named.content_type->md))[EXPECTED_CONTENT_TYPE_LENGTH] ==
+               '+' ||
+           GRPC_SLICE_START_PTR(GRPC_MDVALUE(
+               b->idx.named.content_type->md))[EXPECTED_CONTENT_TYPE_LENGTH] ==
+               ';')) {
+        /* Although the C implementation doesn't (currently) generate them,
+           any custom +-suffix is explicitly valid. */
+        /* TODO(klempner): We should consider preallocating common values such
+           as +proto or +json, or at least stashing them if we see them. */
+        /* TODO(klempner): Should we be surfacing this to application code? */
+      } else {
+        /* TODO(klempner): We're currently allowing this, but we shouldn't
+           see it without a proxy so log for now. */
+        char *val = grpc_dump_slice(GRPC_MDVALUE(b->idx.named.content_type->md),
+                                    GPR_DUMP_ASCII);
+        gpr_log(GPR_INFO, "Unexpected content-type '%s'", val);
+        gpr_free(val);
+      }
+    }
+    grpc_metadata_batch_remove(exec_ctx, b, b->idx.named.content_type);
+  }
+
+  return GRPC_ERROR_NONE;
 }
 
 static void hc_on_recv_initial_metadata(grpc_exec_ctx *exec_ctx,
                                         void *user_data, grpc_error *error) {
   grpc_call_element *elem = user_data;
   call_data *calld = elem->call_data;
-  grpc_metadata_batch_filter(exec_ctx, calld->recv_initial_metadata,
-                             client_recv_filter, elem);
-  grpc_closure_run(exec_ctx, calld->on_done_recv_initial_metadata,
-                   GRPC_ERROR_REF(error));
+  if (error == GRPC_ERROR_NONE) {
+    error = client_filter_incoming_metadata(exec_ctx, elem,
+                                            calld->recv_initial_metadata);
+  } else {
+    GRPC_ERROR_REF(error);
+  }
+  grpc_closure_run(exec_ctx, calld->on_done_recv_initial_metadata, error);
 }
 
 static void hc_on_recv_trailing_metadata(grpc_exec_ctx *exec_ctx,
                                          void *user_data, grpc_error *error) {
   grpc_call_element *elem = user_data;
   call_data *calld = elem->call_data;
-  grpc_metadata_batch_filter(exec_ctx, calld->recv_trailing_metadata,
-                             client_recv_filter, elem);
-  grpc_closure_run(exec_ctx, calld->on_done_recv_trailing_metadata,
-                   GRPC_ERROR_REF(error));
+  if (error == GRPC_ERROR_NONE) {
+    error = client_filter_incoming_metadata(exec_ctx, elem,
+                                            calld->recv_trailing_metadata);
+  } else {
+    GRPC_ERROR_REF(error);
+  }
+  grpc_closure_run(exec_ctx, calld->on_done_recv_trailing_metadata, error);
 }
 
 static void hc_on_complete(grpc_exec_ctx *exec_ctx, void *user_data,
@@ -179,15 +207,12 @@ static void send_done(grpc_exec_ctx *exec_ctx, void *elemp, grpc_error *error) {
   calld->post_send->cb(exec_ctx, calld->post_send->cb_arg, error);
 }
 
-static grpc_mdelem *client_strip_filter(grpc_exec_ctx *exec_ctx,
-                                        void *user_data, grpc_mdelem *md) {
-  /* eat the things we'd like to set ourselves */
-  if (md->key == GRPC_MDSTR_METHOD) return NULL;
-  if (md->key == GRPC_MDSTR_SCHEME) return NULL;
-  if (md->key == GRPC_MDSTR_TE) return NULL;
-  if (md->key == GRPC_MDSTR_CONTENT_TYPE) return NULL;
-  if (md->key == GRPC_MDSTR_USER_AGENT) return NULL;
-  return md;
+static void remove_if_present(grpc_exec_ctx *exec_ctx,
+                              grpc_metadata_batch *batch,
+                              grpc_metadata_batch_callouts_index idx) {
+  if (batch->idx.array[idx] != NULL) {
+    grpc_metadata_batch_remove(exec_ctx, batch, batch->idx.array[idx]);
+  }
 }
 
 static void continue_send_message(grpc_exec_ctx *exec_ctx,
@@ -226,18 +251,20 @@ static void got_slice(grpc_exec_ctx *exec_ctx, void *elemp, grpc_error *error) {
   }
 }
 
-static void hc_mutate_op(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
-                         grpc_transport_stream_op *op) {
+static grpc_error *hc_mutate_op(grpc_exec_ctx *exec_ctx,
+                                grpc_call_element *elem,
+                                grpc_transport_stream_op *op) {
   /* grab pointers to our data from the call element */
   call_data *calld = elem->call_data;
   channel_data *channeld = elem->channel_data;
+  grpc_error *error;
 
   if (op->send_initial_metadata != NULL) {
     /* Decide which HTTP VERB to use. We use GET if the request is marked
     cacheable, and the operation contains both initial metadata and send
     message, and the payload is below the size threshold, and all the data
     for this request is immediately available. */
-    grpc_mdelem *method = GRPC_MDELEM_METHOD_POST;
+    grpc_mdelem method = GRPC_MDELEM_METHOD_POST;
     if ((op->send_initial_metadata_flags &
          GRPC_INITIAL_METADATA_CACHEABLE_REQUEST) &&
         op->send_message != NULL &&
@@ -254,7 +281,7 @@ static void hc_mutate_op(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
     }
 
     /* Attempt to read the data from send_message and create a header field. */
-    if (method == GRPC_MDELEM_METHOD_GET) {
+    if (grpc_mdelem_eq(method, GRPC_MDELEM_METHOD_GET)) {
       /* allocate memory to hold the entire payload */
       calld->payload_bytes = gpr_malloc(op->send_message->length);
 
@@ -267,12 +294,14 @@ static void hc_mutate_op(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
       if (calld->send_message_blocked == false) {
         /* when all the send_message data is available, then create a MDELEM and
         append to headers */
-        grpc_mdelem *payload_bin = grpc_mdelem_from_metadata_strings(
+        grpc_mdelem payload_bin = grpc_mdelem_from_slices(
             exec_ctx, GRPC_MDSTR_GRPC_PAYLOAD_BIN,
-            grpc_mdstr_from_buffer(calld->payload_bytes,
-                                   op->send_message->length));
-        grpc_metadata_batch_add_tail(op->send_initial_metadata,
-                                     &calld->payload_bin, payload_bin);
+            grpc_slice_from_copied_buffer((const char *)calld->payload_bytes,
+                                          op->send_message->length));
+        error =
+            grpc_metadata_batch_add_tail(exec_ctx, op->send_initial_metadata,
+                                         &calld->payload_bin, payload_bin);
+        if (error != GRPC_ERROR_NONE) return error;
         calld->on_complete = op->on_complete;
         op->on_complete = &calld->hc_on_complete;
         op->send_message = NULL;
@@ -285,21 +314,35 @@ static void hc_mutate_op(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
       }
     }
 
-    grpc_metadata_batch_filter(exec_ctx, op->send_initial_metadata,
-                               client_strip_filter, elem);
+    remove_if_present(exec_ctx, op->send_initial_metadata, GRPC_BATCH_METHOD);
+    remove_if_present(exec_ctx, op->send_initial_metadata, GRPC_BATCH_SCHEME);
+    remove_if_present(exec_ctx, op->send_initial_metadata, GRPC_BATCH_TE);
+    remove_if_present(exec_ctx, op->send_initial_metadata,
+                      GRPC_BATCH_CONTENT_TYPE);
+    remove_if_present(exec_ctx, op->send_initial_metadata,
+                      GRPC_BATCH_USER_AGENT);
+
     /* Send : prefixed headers, which have to be before any application
        layer headers. */
-    grpc_metadata_batch_add_head(op->send_initial_metadata, &calld->method,
-                                 method);
-    grpc_metadata_batch_add_head(op->send_initial_metadata, &calld->scheme,
-                                 channeld->static_scheme);
-    grpc_metadata_batch_add_tail(op->send_initial_metadata, &calld->te_trailers,
-                                 GRPC_MDELEM_TE_TRAILERS);
-    grpc_metadata_batch_add_tail(
-        op->send_initial_metadata, &calld->content_type,
+    error = grpc_metadata_batch_add_head(exec_ctx, op->send_initial_metadata,
+                                         &calld->method, method);
+    if (error != GRPC_ERROR_NONE) return error;
+    error =
+        grpc_metadata_batch_add_head(exec_ctx, op->send_initial_metadata,
+                                     &calld->scheme, channeld->static_scheme);
+    if (error != GRPC_ERROR_NONE) return error;
+    error = grpc_metadata_batch_add_tail(exec_ctx, op->send_initial_metadata,
+                                         &calld->te_trailers,
+                                         GRPC_MDELEM_TE_TRAILERS);
+    if (error != GRPC_ERROR_NONE) return error;
+    error = grpc_metadata_batch_add_tail(
+        exec_ctx, op->send_initial_metadata, &calld->content_type,
         GRPC_MDELEM_CONTENT_TYPE_APPLICATION_SLASH_GRPC);
-    grpc_metadata_batch_add_tail(op->send_initial_metadata, &calld->user_agent,
-                                 GRPC_MDELEM_REF(channeld->user_agent));
+    if (error != GRPC_ERROR_NONE) return error;
+    error = grpc_metadata_batch_add_tail(exec_ctx, op->send_initial_metadata,
+                                         &calld->user_agent,
+                                         GRPC_MDELEM_REF(channeld->user_agent));
+    if (error != GRPC_ERROR_NONE) return error;
   }
 
   if (op->recv_initial_metadata != NULL) {
@@ -315,6 +358,8 @@ static void hc_mutate_op(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
     calld->on_done_recv_trailing_metadata = op->on_complete;
     op->on_complete = &calld->hc_on_recv_trailing_metadata;
   }
+
+  return GRPC_ERROR_NONE;
 }
 
 static void hc_start_transport_op(grpc_exec_ctx *exec_ctx,
@@ -322,15 +367,20 @@ static void hc_start_transport_op(grpc_exec_ctx *exec_ctx,
                                   grpc_transport_stream_op *op) {
   GPR_TIMER_BEGIN("hc_start_transport_op", 0);
   GRPC_CALL_LOG_OP(GPR_INFO, elem, op);
-  hc_mutate_op(exec_ctx, elem, op);
-  GPR_TIMER_END("hc_start_transport_op", 0);
-  call_data *calld = elem->call_data;
-  if (op->send_message != NULL && calld->send_message_blocked) {
-    /* Don't forward the op. send_message contains slices that aren't ready
-    yet. The call will be forwarded by the op_complete of slice read call. */
+  grpc_error *error = hc_mutate_op(exec_ctx, elem, op);
+  if (error != GRPC_ERROR_NONE) {
+    grpc_transport_stream_op_finish_with_failure(exec_ctx, op, error);
   } else {
-    grpc_call_next_op(exec_ctx, elem, op);
+    call_data *calld = elem->call_data;
+    if (op->send_message != NULL && calld->send_message_blocked) {
+      /* Don't forward the op. send_message contains slices that aren't ready
+      yet. The call will be forwarded by the op_complete of slice read call.
+      */
+    } else {
+      grpc_call_next_op(exec_ctx, elem, op);
+    }
   }
+  GPR_TIMER_END("hc_start_transport_op", 0);
 }
 
 /* Constructor for call_data */
@@ -367,18 +417,18 @@ static void destroy_call_elem(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
   grpc_slice_buffer_destroy_internal(exec_ctx, &calld->slices);
 }
 
-static grpc_mdelem *scheme_from_args(const grpc_channel_args *args) {
+static grpc_mdelem scheme_from_args(const grpc_channel_args *args) {
   unsigned i;
   size_t j;
-  grpc_mdelem *valid_schemes[] = {GRPC_MDELEM_SCHEME_HTTP,
-                                  GRPC_MDELEM_SCHEME_HTTPS};
+  grpc_mdelem valid_schemes[] = {GRPC_MDELEM_SCHEME_HTTP,
+                                 GRPC_MDELEM_SCHEME_HTTPS};
   if (args != NULL) {
     for (i = 0; i < args->num_args; ++i) {
       if (args->args[i].type == GRPC_ARG_STRING &&
           strcmp(args->args[i].key, GRPC_ARG_HTTP2_SCHEME) == 0) {
         for (j = 0; j < GPR_ARRAY_SIZE(valid_schemes); j++) {
-          if (0 == strcmp(grpc_mdstr_as_c_string(valid_schemes[j]->value),
-                          args->args[i].value.string)) {
+          if (0 == grpc_slice_str_cmp(GRPC_MDVALUE(valid_schemes[j]),
+                                      args->args[i].value.string)) {
             return valid_schemes[j];
           }
         }
@@ -404,13 +454,13 @@ static size_t max_payload_size_from_args(const grpc_channel_args *args) {
   return kMaxPayloadSizeForGet;
 }
 
-static grpc_mdstr *user_agent_from_args(const grpc_channel_args *args,
-                                        const char *transport_name) {
+static grpc_slice user_agent_from_args(const grpc_channel_args *args,
+                                       const char *transport_name) {
   gpr_strvec v;
   size_t i;
   int is_first = 1;
   char *tmp;
-  grpc_mdstr *result;
+  grpc_slice result;
 
   gpr_strvec_init(&v);
 
@@ -448,7 +498,7 @@ static grpc_mdstr *user_agent_from_args(const grpc_channel_args *args,
 
   tmp = gpr_strvec_flatten(&v, NULL);
   gpr_strvec_destroy(&v);
-  result = grpc_mdstr_from_string(tmp);
+  result = grpc_slice_intern(grpc_slice_from_static_string(tmp));
   gpr_free(tmp);
 
   return result;
@@ -464,7 +514,7 @@ static grpc_error *init_channel_elem(grpc_exec_ctx *exec_ctx,
   chand->static_scheme = scheme_from_args(args->channel_args);
   chand->max_payload_size_for_get =
       max_payload_size_from_args(args->channel_args);
-  chand->user_agent = grpc_mdelem_from_metadata_strings(
+  chand->user_agent = grpc_mdelem_from_slices(
       exec_ctx, GRPC_MDSTR_USER_AGENT,
       user_agent_from_args(args->channel_args,
                            args->optional_transport->vtable->name));

src/core/lib/channel/http_server_filter.c

@@ -39,6 +39,7 @@
 #include "src/core/lib/profiling/timers.h"
 #include "src/core/lib/slice/percent_encoding.h"
 #include "src/core/lib/slice/slice_internal.h"
+#include "src/core/lib/slice/slice_string_helpers.h"
 #include "src/core/lib/transport/static_metadata.h"
 
 #define EXPECTED_CONTENT_TYPE "application/grpc"
@@ -47,18 +48,13 @@
 extern int grpc_http_trace;
 
 typedef struct call_data {
-  uint8_t seen_path;
-  uint8_t seen_method;
-  uint8_t sent_status;
-  uint8_t seen_scheme;
-  uint8_t seen_te_trailers;
-  uint8_t seen_authority;
-  uint8_t seen_payload_bin;
   grpc_linked_mdelem status;
   grpc_linked_mdelem content_type;
 
+  /* did this request come with payload-bin */
+  bool seen_payload_bin;
   /* flag to ensure payload_bin is delivered only once */
-  uint8_t payload_bin_delivered;
+  bool payload_bin_delivered;
 
   grpc_metadata_batch *recv_initial_metadata;
   bool *recv_idempotent_request;
@@ -83,109 +79,152 @@ typedef struct call_data {
 
 typedef struct channel_data { uint8_t unused; } channel_data;
 
-static grpc_mdelem *server_filter_outgoing_metadata(grpc_exec_ctx *exec_ctx,
-                                                    void *user_data,
-                                                    grpc_mdelem *md) {
-  if (md->key == GRPC_MDSTR_GRPC_MESSAGE) {
+static grpc_error *server_filter_outgoing_metadata(grpc_exec_ctx *exec_ctx,
+                                                   grpc_call_element *elem,
+                                                   grpc_metadata_batch *b) {
+  if (b->idx.named.grpc_message != NULL) {
     grpc_slice pct_encoded_msg = grpc_percent_encode_slice(
-        md->value->slice, grpc_compatible_percent_encoding_unreserved_bytes);
-    if (grpc_slice_is_equivalent(pct_encoded_msg, md->value->slice)) {
+        GRPC_MDVALUE(b->idx.named.grpc_message->md),
+        grpc_compatible_percent_encoding_unreserved_bytes);
+    if (grpc_slice_is_equivalent(pct_encoded_msg,
+                                 GRPC_MDVALUE(b->idx.named.grpc_message->md))) {
       grpc_slice_unref_internal(exec_ctx, pct_encoded_msg);
-      return md;
     } else {
-      return grpc_mdelem_from_metadata_strings(
-          exec_ctx, GRPC_MDSTR_GRPC_MESSAGE,
-          grpc_mdstr_from_slice(exec_ctx, pct_encoded_msg));
+      grpc_metadata_batch_set_value(exec_ctx, b->idx.named.grpc_message,
+                                    pct_encoded_msg);
     }
-  } else {
-    return md;
   }
+  return GRPC_ERROR_NONE;
 }
 
-static grpc_mdelem *server_filter(grpc_exec_ctx *exec_ctx, void *user_data,
-                                  grpc_mdelem *md) {
-  grpc_call_element *elem = user_data;
+static void add_error(const char *error_name, grpc_error **cumulative,
+                      grpc_error *new) {
+  if (new == GRPC_ERROR_NONE) return;
+  if (*cumulative == GRPC_ERROR_NONE) {
+    *cumulative = GRPC_ERROR_CREATE(error_name);
+  }
+  *cumulative = grpc_error_add_child(*cumulative, new);
+}
+
+static grpc_error *server_filter_incoming_metadata(grpc_exec_ctx *exec_ctx,
+                                                   grpc_call_element *elem,
+                                                   grpc_metadata_batch *b) {
   call_data *calld = elem->call_data;
+  grpc_error *error = GRPC_ERROR_NONE;
+  static const char *error_name = "Failed processing incoming headers";
 
-  /* Check if it is one of the headers we care about. */
-  if (md == GRPC_MDELEM_TE_TRAILERS || md == GRPC_MDELEM_METHOD_POST ||
-      md == GRPC_MDELEM_METHOD_PUT || md == GRPC_MDELEM_METHOD_GET ||
-      md == GRPC_MDELEM_SCHEME_HTTP || md == GRPC_MDELEM_SCHEME_HTTPS ||
-      md == GRPC_MDELEM_CONTENT_TYPE_APPLICATION_SLASH_GRPC) {
-    /* swallow it */
-    if (md == GRPC_MDELEM_METHOD_POST) {
-      calld->seen_method = 1;
+  if (b->idx.named.method != NULL) {
+    if (grpc_mdelem_eq(b->idx.named.method->md, GRPC_MDELEM_METHOD_POST)) {
       *calld->recv_idempotent_request = false;
       *calld->recv_cacheable_request = false;
-    } else if (md == GRPC_MDELEM_METHOD_PUT) {
-      calld->seen_method = 1;
+    } else if (grpc_mdelem_eq(b->idx.named.method->md,
+                              GRPC_MDELEM_METHOD_PUT)) {
       *calld->recv_idempotent_request = true;
-    } else if (md == GRPC_MDELEM_METHOD_GET) {
-      calld->seen_method = 1;
+    } else if (grpc_mdelem_eq(b->idx.named.method->md,
+                              GRPC_MDELEM_METHOD_GET)) {
       *calld->recv_cacheable_request = true;
-    } else if (md->key == GRPC_MDSTR_SCHEME) {
-      calld->seen_scheme = 1;
-    } else if (md == GRPC_MDELEM_TE_TRAILERS) {
-      calld->seen_te_trailers = 1;
-    }
-    /* TODO(klempner): Track that we've seen all the headers we should
-       require */
-    return NULL;
-  } else if (md->key == GRPC_MDSTR_CONTENT_TYPE) {
-    const char *value_str = grpc_mdstr_as_c_string(md->value);
-    if (strncmp(value_str, EXPECTED_CONTENT_TYPE,
-                EXPECTED_CONTENT_TYPE_LENGTH) == 0 &&
-        (value_str[EXPECTED_CONTENT_TYPE_LENGTH] == '+' ||
-         value_str[EXPECTED_CONTENT_TYPE_LENGTH] == ';')) {
-      /* Although the C implementation doesn't (currently) generate them,
-         any custom +-suffix is explicitly valid. */
-      /* TODO(klempner): We should consider preallocating common values such
-         as +proto or +json, or at least stashing them if we see them. */
-      /* TODO(klempner): Should we be surfacing this to application code? */
     } else {
-      /* TODO(klempner): We're currently allowing this, but we shouldn't
-         see it without a proxy so log for now. */
-      gpr_log(GPR_INFO, "Unexpected content-type '%s'", value_str);
+      add_error(error_name, &error,
+                grpc_attach_md_to_error(GRPC_ERROR_CREATE("Bad header"),
+                                        b->idx.named.method->md));
+    }
+    grpc_metadata_batch_remove(exec_ctx, b, b->idx.named.method);
+  } else {
+    add_error(error_name, &error,
+              grpc_error_set_str(GRPC_ERROR_CREATE("Missing header"),
+                                 GRPC_ERROR_STR_KEY, ":method"));
+  }
+
+  if (b->idx.named.te != NULL) {
+    if (!grpc_mdelem_eq(b->idx.named.te->md, GRPC_MDELEM_TE_TRAILERS)) {
+      add_error(error_name, &error,
+                grpc_attach_md_to_error(GRPC_ERROR_CREATE("Bad header"),
+                                        b->idx.named.te->md));
+    }
+    grpc_metadata_batch_remove(exec_ctx, b, b->idx.named.te);
+  } else {
+    add_error(error_name, &error,
+              grpc_error_set_str(GRPC_ERROR_CREATE("Missing header"),
+                                 GRPC_ERROR_STR_KEY, "te"));
+  }
+
+  if (b->idx.named.scheme != NULL) {
+    if (!grpc_mdelem_eq(b->idx.named.scheme->md, GRPC_MDELEM_SCHEME_HTTP) &&
+        !grpc_mdelem_eq(b->idx.named.scheme->md, GRPC_MDELEM_SCHEME_HTTPS) &&
+        !grpc_mdelem_eq(b->idx.named.scheme->md, GRPC_MDELEM_SCHEME_GRPC)) {
+      add_error(error_name, &error,
+                grpc_attach_md_to_error(GRPC_ERROR_CREATE("Bad header"),
+                                        b->idx.named.scheme->md));
     }
-    return NULL;
-  } else if (md->key == GRPC_MDSTR_TE || md->key == GRPC_MDSTR_METHOD ||
-             md->key == GRPC_MDSTR_SCHEME) {
-    gpr_log(GPR_ERROR, "Invalid %s: header: '%s'",
-            grpc_mdstr_as_c_string(md->key), grpc_mdstr_as_c_string(md->value));
-    /* swallow it and error everything out. */
-    /* TODO(klempner): We ought to generate more descriptive error messages
-       on the wire here. */
-    grpc_call_element_send_cancel(exec_ctx, elem);
-    return NULL;
-  } else if (md->key == GRPC_MDSTR_PATH) {
-    if (calld->seen_path) {
-      gpr_log(GPR_ERROR, "Received :path twice");
-      return NULL;
+    grpc_metadata_batch_remove(exec_ctx, b, b->idx.named.scheme);
+  } else {
+    add_error(error_name, &error,
+              grpc_error_set_str(GRPC_ERROR_CREATE("Missing header"),
+                                 GRPC_ERROR_STR_KEY, ":scheme"));
+  }
+
+  if (b->idx.named.content_type != NULL) {
+    if (!grpc_mdelem_eq(b->idx.named.content_type->md,
+                        GRPC_MDELEM_CONTENT_TYPE_APPLICATION_SLASH_GRPC)) {
+      if (grpc_slice_buf_start_eq(GRPC_MDVALUE(b->idx.named.content_type->md),
+                                  EXPECTED_CONTENT_TYPE,
+                                  EXPECTED_CONTENT_TYPE_LENGTH) &&
+          (GRPC_SLICE_START_PTR(GRPC_MDVALUE(
+               b->idx.named.content_type->md))[EXPECTED_CONTENT_TYPE_LENGTH] ==
+               '+' ||
+           GRPC_SLICE_START_PTR(GRPC_MDVALUE(
+               b->idx.named.content_type->md))[EXPECTED_CONTENT_TYPE_LENGTH] ==
+               ';')) {
+        /* Although the C implementation doesn't (currently) generate them,
+           any custom +-suffix is explicitly valid. */
+        /* TODO(klempner): We should consider preallocating common values such
+           as +proto or +json, or at least stashing them if we see them. */
+        /* TODO(klempner): Should we be surfacing this to application code? */
+      } else {
+        /* TODO(klempner): We're currently allowing this, but we shouldn't
+           see it without a proxy so log for now. */
+        char *val = grpc_dump_slice(GRPC_MDVALUE(b->idx.named.content_type->md),
+                                    GPR_DUMP_ASCII);
+        gpr_log(GPR_INFO, "Unexpected content-type '%s'", val);
+        gpr_free(val);
+      }
     }
-    calld->seen_path = 1;
-    return md;
-  } else if (md->key == GRPC_MDSTR_AUTHORITY) {
-    calld->seen_authority = 1;
-    return md;
-  } else if (md->key == GRPC_MDSTR_HOST) {
-    /* translate host to :authority since :authority may be
-       omitted */
-    grpc_mdelem *authority = grpc_mdelem_from_metadata_strings(
-        exec_ctx, GRPC_MDSTR_AUTHORITY, GRPC_MDSTR_REF(md->value));
-    calld->seen_authority = 1;
-    return authority;
-  } else if (md->key == GRPC_MDSTR_GRPC_PAYLOAD_BIN) {
-    /* Retrieve the payload from the value of the 'grpc-internal-payload-bin'
-       header field */
-    calld->seen_payload_bin = 1;
+    grpc_metadata_batch_remove(exec_ctx, b, b->idx.named.content_type);
+  }
+
+  if (b->idx.named.path == NULL) {
+    add_error(error_name, &error,
+              grpc_error_set_str(GRPC_ERROR_CREATE("Missing header"),
+                                 GRPC_ERROR_STR_KEY, ":path"));
+  }
+
+  if (b->idx.named.host != NULL) {
+    add_error(
+        error_name, &error,
+        grpc_metadata_batch_substitute(
+            exec_ctx, b, b->idx.named.host,
+            grpc_mdelem_from_slices(
+                exec_ctx, GRPC_MDSTR_AUTHORITY,
+                grpc_slice_ref_internal(GRPC_MDVALUE(b->idx.named.host->md)))));
+  }
+
+  if (b->idx.named.authority == NULL) {
+    add_error(error_name, &error,
+              grpc_error_set_str(GRPC_ERROR_CREATE("Missing header"),
+                                 GRPC_ERROR_STR_KEY, ":authority"));
+  }
+
+  if (b->idx.named.grpc_payload_bin != NULL) {
+    calld->seen_payload_bin = true;
     grpc_slice_buffer_add(&calld->read_slice_buffer,
-                          grpc_slice_ref_internal(md->value->slice));
+                          grpc_slice_ref_internal(
+                              GRPC_MDVALUE(b->idx.named.grpc_payload_bin->md)));
     grpc_slice_buffer_stream_init(&calld->read_stream,
                                   &calld->read_slice_buffer, 0);
-    return NULL;
-  } else {
-    return md;
+    grpc_metadata_batch_remove(exec_ctx, b, b->idx.named.grpc_payload_bin);
   }
+
+  return error;
 }
 
 static void hs_on_recv(grpc_exec_ctx *exec_ctx, void *user_data,
@@ -193,49 +232,12 @@ static void hs_on_recv(grpc_exec_ctx *exec_ctx, void *user_data,
   grpc_call_element *elem = user_data;
   call_data *calld = elem->call_data;
   if (err == GRPC_ERROR_NONE) {
-    grpc_metadata_batch_filter(exec_ctx, calld->recv_initial_metadata,
-                               server_filter, elem);
-    /* Have we seen the required http2 transport headers?
-       (:method, :scheme, content-type, with :path and :authority covered
-       at the channel level right now) */
-    if (calld->seen_method && calld->seen_scheme && calld->seen_te_trailers &&
-        calld->seen_path && calld->seen_authority) {
-      /* do nothing */
-    } else {
-      err = GRPC_ERROR_CREATE("Bad incoming HTTP headers");
-      if (!calld->seen_path) {
-        err = grpc_error_add_child(err,
-                                   GRPC_ERROR_CREATE("Missing :path header"));
-      }
-      if (!calld->seen_authority) {
-        err = grpc_error_add_child(
-            err, GRPC_ERROR_CREATE("Missing :authority header"));
-      }
-      if (!calld->seen_method) {
-        err = grpc_error_add_child(err,
-                                   GRPC_ERROR_CREATE("Missing :method header"));
-      }
-      if (!calld->seen_scheme) {
-        err = grpc_error_add_child(err,
-                                   GRPC_ERROR_CREATE("Missing :scheme header"));
-      }
-      if (!calld->seen_te_trailers) {
-        err = grpc_error_add_child(
-            err, GRPC_ERROR_CREATE("Missing te: trailers header"));
-      }
-      /* Error this call out */
-      if (grpc_http_trace) {
-        const char *error_str = grpc_error_string(err);
-        gpr_log(GPR_ERROR, "Invalid http2 headers: %s", error_str);
-        grpc_error_free_string(error_str);
-      }
-      grpc_call_element_send_cancel(exec_ctx, elem);
-    }
+    err = server_filter_incoming_metadata(exec_ctx, elem,
+                                          calld->recv_initial_metadata);
   } else {
     GRPC_ERROR_REF(err);
   }
-  calld->on_done_recv->cb(exec_ctx, calld->on_done_recv->cb_arg, err);
-  GRPC_ERROR_UNREF(err);
+  grpc_closure_run(exec_ctx, calld->on_done_recv, err);
 }
 
 static void hs_on_complete(grpc_exec_ctx *exec_ctx, void *user_data,
@@ -273,13 +275,23 @@ static void hs_mutate_op(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
   /* grab pointers to our data from the call element */
   call_data *calld = elem->call_data;
 
-  if (op->send_initial_metadata != NULL && !calld->sent_status) {
-    calld->sent_status = 1;
-    grpc_metadata_batch_add_head(op->send_initial_metadata, &calld->status,
-                                 GRPC_MDELEM_STATUS_200);
-    grpc_metadata_batch_add_tail(
-        op->send_initial_metadata, &calld->content_type,
-        GRPC_MDELEM_CONTENT_TYPE_APPLICATION_SLASH_GRPC);
+  if (op->send_initial_metadata != NULL) {
+    grpc_error *error = GRPC_ERROR_NONE;
+    static const char *error_name = "Failed sending initial metadata";
+    add_error(error_name, &error, grpc_metadata_batch_add_head(
+                                      exec_ctx, op->send_initial_metadata,
+                                      &calld->status, GRPC_MDELEM_STATUS_200));
+    add_error(error_name, &error,
+              grpc_metadata_batch_add_tail(
+                  exec_ctx, op->send_initial_metadata, &calld->content_type,
+                  GRPC_MDELEM_CONTENT_TYPE_APPLICATION_SLASH_GRPC));
+    add_error(error_name, &error,
+              server_filter_outgoing_metadata(exec_ctx, elem,
+                                              op->send_initial_metadata));
+    if (error != GRPC_ERROR_NONE) {
+      grpc_transport_stream_op_finish_with_failure(exec_ctx, op, error);
+      return;
+    }
   }
 
   if (op->recv_initial_metadata) {
@@ -306,8 +318,12 @@ static void hs_mutate_op(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
   }
 
   if (op->send_trailing_metadata) {
-    grpc_metadata_batch_filter(exec_ctx, op->send_trailing_metadata,
-                               server_filter_outgoing_metadata, elem);
+    grpc_error *error = server_filter_outgoing_metadata(
+        exec_ctx, elem, op->send_trailing_metadata);
+    if (error != GRPC_ERROR_NONE) {
+      grpc_transport_stream_op_finish_with_failure(exec_ctx, op, error);
+      return;
+    }
   }
 }
 

src/core/lib/channel/message_size_filter.c

@@ -58,7 +58,7 @@ static void message_size_limits_free(grpc_exec_ctx* exec_ctx, void* value) {
   gpr_free(value);
 }
 
-static const grpc_mdstr_hash_table_vtable message_size_limits_vtable = {
+static const grpc_slice_hash_table_vtable message_size_limits_vtable = {
     message_size_limits_free, message_size_limits_copy};
 
 static void* message_size_limits_create_from_json(const grpc_json* json) {
@@ -101,7 +101,7 @@ typedef struct channel_data {
   int max_send_size;
   int max_recv_size;
   // Maps path names to message_size_limits structs.
-  grpc_mdstr_hash_table* method_limit_table;
+  grpc_slice_hash_table* method_limit_table;
 } channel_data;
 
 // Callback invoked when we receive a message.  Here we check the max
@@ -142,10 +142,12 @@ static void start_transport_stream_op(grpc_exec_ctx* exec_ctx,
     char* message_string;
     gpr_asprintf(&message_string, "Sent message larger than max (%u vs. %d)",
                  op->send_message->length, calld->max_send_size);
-    grpc_slice message = grpc_slice_from_copied_string(message_string);
+    grpc_transport_stream_op_finish_with_failure(
+        exec_ctx, op, grpc_error_set_int(GRPC_ERROR_CREATE(message_string),
+                                         GRPC_ERROR_INT_GRPC_STATUS,
+                                         GRPC_STATUS_INVALID_ARGUMENT));
     gpr_free(message_string);
-    grpc_call_element_send_close_with_message(
-        exec_ctx, elem, GRPC_STATUS_INVALID_ARGUMENT, &message);
+    return;
   }
   // Inject callback for receiving a message.
   if (op->recv_message_ready != NULL) {
@@ -243,7 +245,7 @@ static grpc_error* init_channel_elem(grpc_exec_ctx* exec_ctx,
 static void destroy_channel_elem(grpc_exec_ctx* exec_ctx,
                                  grpc_channel_element* elem) {
   channel_data* chand = elem->channel_data;
-  grpc_mdstr_hash_table_unref(exec_ctx, chand->method_limit_table);
+  grpc_slice_hash_table_unref(exec_ctx, chand->method_limit_table);
 }
 
 const grpc_channel_filter grpc_message_size_filter = {

src/core/lib/compression/algorithm_metadata.h

@@ -38,16 +38,16 @@
 #include "src/core/lib/transport/metadata.h"
 
 /** Return compression algorithm based metadata value */
-grpc_mdstr *grpc_compression_algorithm_mdstr(
+grpc_slice grpc_compression_algorithm_slice(
     grpc_compression_algorithm algorithm);
 
 /** Return compression algorithm based metadata element (grpc-encoding: xxx) */
-grpc_mdelem *grpc_compression_encoding_mdelem(
+grpc_mdelem grpc_compression_encoding_mdelem(
     grpc_compression_algorithm algorithm);
 
 /** Find compression algorithm based on passed in mdstr - returns
  * GRPC_COMPRESS_ALGORITHM_COUNT on failure */
-grpc_compression_algorithm grpc_compression_algorithm_from_mdstr(
-    grpc_mdstr *str);
+grpc_compression_algorithm grpc_compression_algorithm_from_slice(
+    grpc_slice str);
 
 #endif /* GRPC_CORE_LIB_COMPRESSION_ALGORITHM_METADATA_H */

src/core/lib/compression/compression.c

@@ -41,30 +41,24 @@
 #include "src/core/lib/surface/api_trace.h"
 #include "src/core/lib/transport/static_metadata.h"
 
-int grpc_compression_algorithm_parse(const char *name, size_t name_length,
+int grpc_compression_algorithm_parse(grpc_slice name,
                                      grpc_compression_algorithm *algorithm) {
   /* we use strncmp not only because it's safer (even though in this case it
    * doesn't matter, given that we are comparing against string literals, but
    * because this way we needn't have "name" nil-terminated (useful for slice
    * data, for example) */
-  GRPC_API_TRACE(
-      "grpc_compression_algorithm_parse("
-      "name=%*.*s, name_length=%lu, algorithm=%p)",
-      5, ((int)name_length, (int)name_length, name, (unsigned long)name_length,
-          algorithm));
-  if (name_length == 0) {
-    return 0;
-  }
-  if (strncmp(name, "identity", name_length) == 0) {
+  if (grpc_slice_eq(name, GRPC_MDSTR_IDENTITY)) {
     *algorithm = GRPC_COMPRESS_NONE;
-  } else if (strncmp(name, "gzip", name_length) == 0) {
+    return 1;
+  } else if (grpc_slice_eq(name, GRPC_MDSTR_GZIP)) {
     *algorithm = GRPC_COMPRESS_GZIP;
-  } else if (strncmp(name, "deflate", name_length) == 0) {
+    return 1;
+  } else if (grpc_slice_eq(name, GRPC_MDSTR_DEFLATE)) {
     *algorithm = GRPC_COMPRESS_DEFLATE;
+    return 1;
   } else {
     return 0;
   }
-  return 1;
 }
 
 int grpc_compression_algorithm_name(grpc_compression_algorithm algorithm,
@@ -87,15 +81,15 @@ int grpc_compression_algorithm_name(grpc_compression_algorithm algorithm,
   return 0;
 }
 
-grpc_compression_algorithm grpc_compression_algorithm_from_mdstr(
-    grpc_mdstr *str) {
-  if (str == GRPC_MDSTR_IDENTITY) return GRPC_COMPRESS_NONE;
-  if (str == GRPC_MDSTR_DEFLATE) return GRPC_COMPRESS_DEFLATE;
-  if (str == GRPC_MDSTR_GZIP) return GRPC_COMPRESS_GZIP;
+grpc_compression_algorithm grpc_compression_algorithm_from_slice(
+    grpc_slice str) {
+  if (grpc_slice_eq(str, GRPC_MDSTR_IDENTITY)) return GRPC_COMPRESS_NONE;
+  if (grpc_slice_eq(str, GRPC_MDSTR_DEFLATE)) return GRPC_COMPRESS_DEFLATE;
+  if (grpc_slice_eq(str, GRPC_MDSTR_GZIP)) return GRPC_COMPRESS_GZIP;
   return GRPC_COMPRESS_ALGORITHMS_COUNT;
 }
 
-grpc_mdstr *grpc_compression_algorithm_mdstr(
+grpc_slice grpc_compression_algorithm_slice(
     grpc_compression_algorithm algorithm) {
   switch (algorithm) {
     case GRPC_COMPRESS_NONE:
@@ -105,12 +99,12 @@ grpc_mdstr *grpc_compression_algorithm_mdstr(
     case GRPC_COMPRESS_GZIP:
       return GRPC_MDSTR_GZIP;
     case GRPC_COMPRESS_ALGORITHMS_COUNT:
-      return NULL;
+      return grpc_empty_slice();
   }
-  return NULL;
+  return grpc_empty_slice();
 }
 
-grpc_mdelem *grpc_compression_encoding_mdelem(
+grpc_mdelem grpc_compression_encoding_mdelem(
     grpc_compression_algorithm algorithm) {
   switch (algorithm) {
     case GRPC_COMPRESS_NONE:
@@ -122,7 +116,7 @@ grpc_mdelem *grpc_compression_encoding_mdelem(
     default:
       break;
   }
-  return NULL;
+  return GRPC_MDNULL;
 }
 
 void grpc_compression_options_init(grpc_compression_options *opts) {

src/core/lib/http/httpcli_security_connector.c

@@ -156,7 +156,7 @@ static void on_handshake_done(grpc_exec_ctx *exec_ctx, void *arg,
   if (error != GRPC_ERROR_NONE) {
     const char *msg = grpc_error_string(error);
     gpr_log(GPR_ERROR, "Secure transport setup failed: %s", msg);
-    grpc_error_free_string(msg);
+
     c->func(exec_ctx, c->arg, NULL);
   } else {
     grpc_channel_args_destroy(exec_ctx, args->args);

src/core/lib/iomgr/closure.c

@@ -34,6 +34,7 @@
 #include "src/core/lib/iomgr/closure.h"
 
 #include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
 
 #include "src/core/lib/profiling/timers.h"
 

src/core/lib/iomgr/closure.h

@@ -66,6 +66,7 @@ typedef struct grpc_closure_scheduler_vtable {
               grpc_error *error);
   void (*sched)(grpc_exec_ctx *exec_ctx, grpc_closure *closure,
                 grpc_error *error);
+  const char *name;
 } grpc_closure_scheduler_vtable;
 
 /** Abstract type that can schedule closures for execution */

src/core/lib/iomgr/combiner.c

@@ -86,13 +86,17 @@ static void combiner_finally_exec_covered(grpc_exec_ctx *exec_ctx,
                                           grpc_error *error);
 
 static const grpc_closure_scheduler_vtable scheduler_uncovered = {
-    combiner_exec_uncovered, combiner_exec_uncovered};
+    combiner_exec_uncovered, combiner_exec_uncovered,
+    "combiner:immediately:uncovered"};
 static const grpc_closure_scheduler_vtable scheduler_covered = {
-    combiner_exec_covered, combiner_exec_covered};
+    combiner_exec_covered, combiner_exec_covered,
+    "combiner:immediately:covered"};
 static const grpc_closure_scheduler_vtable finally_scheduler_uncovered = {
-    combiner_finally_exec_uncovered, combiner_finally_exec_uncovered};
+    combiner_finally_exec_uncovered, combiner_finally_exec_uncovered,
+    "combiner:finally:uncovered"};
 static const grpc_closure_scheduler_vtable finally_scheduler_covered = {
-    combiner_finally_exec_covered, combiner_finally_exec_covered};
+    combiner_finally_exec_covered, combiner_finally_exec_covered,
+    "combiner:finally:covered"};
 
 static void offload(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error);
 

src/core/lib/iomgr/error.c

@@ -33,13 +33,10 @@
 
 #include "src/core/lib/iomgr/error.h"
 
-#include <inttypes.h>
-#include <stdbool.h>
 #include <string.h>
 
 #include <grpc/status.h>
 #include <grpc/support/alloc.h>
-#include <grpc/support/avl.h>
 #include <grpc/support/log.h>
 #include <grpc/support/string_util.h>
 #include <grpc/support/useful.h>
@@ -48,6 +45,7 @@
 #include <grpc/support/log_windows.h>
 #endif
 
+#include "src/core/lib/iomgr/error_internal.h"
 #include "src/core/lib/profiling/timers.h"
 
 static void destroy_integer(void *key) {}
@@ -128,6 +126,10 @@ static const char *error_int_name(grpc_error_ints key) {
 
 static const char *error_str_name(grpc_error_strs key) {
   switch (key) {
+    case GRPC_ERROR_STR_KEY:
+      return "key";
+    case GRPC_ERROR_STR_VALUE:
+      return "value";
     case GRPC_ERROR_STR_DESCRIPTION:
       return "description";
     case GRPC_ERROR_STR_OS_ERROR:
@@ -160,16 +162,7 @@ static const char *error_time_name(grpc_error_times key) {
   GPR_UNREACHABLE_CODE(return "unknown");
 }
 
-struct grpc_error {
-  gpr_refcount refs;
-  gpr_avl ints;
-  gpr_avl strs;
-  gpr_avl times;
-  gpr_avl errs;
-  uintptr_t next_err;
-};
-
-static bool is_special(grpc_error *err) {
+bool grpc_error_is_special(grpc_error *err) {
   return err == GRPC_ERROR_NONE || err == GRPC_ERROR_OOM ||
          err == GRPC_ERROR_CANCELLED;
 }
@@ -177,7 +170,7 @@ static bool is_special(grpc_error *err) {
 #ifdef GRPC_ERROR_REFCOUNT_DEBUG
 grpc_error *grpc_error_ref(grpc_error *err, const char *file, int line,
                            const char *func) {
-  if (is_special(err)) return err;
+  if (grpc_error_is_special(err)) return err;
   gpr_log(GPR_DEBUG, "%p: %" PRIdPTR " -> %" PRIdPTR " [%s:%d %s]", err,
           err->refs.count, err->refs.count + 1, file, line, func);
   gpr_ref(&err->refs);
@@ -185,25 +178,26 @@ grpc_error *grpc_error_ref(grpc_error *err, const char *file, int line,
 }
 #else
 grpc_error *grpc_error_ref(grpc_error *err) {
-  if (is_special(err)) return err;
+  if (grpc_error_is_special(err)) return err;
   gpr_ref(&err->refs);
   return err;
 }
 #endif
 
 static void error_destroy(grpc_error *err) {
-  GPR_ASSERT(!is_special(err));
+  GPR_ASSERT(!grpc_error_is_special(err));
   gpr_avl_unref(err->ints);
   gpr_avl_unref(err->strs);
   gpr_avl_unref(err->errs);
   gpr_avl_unref(err->times);
+  gpr_free((void *)gpr_atm_acq_load(&err->error_string));
   gpr_free(err);
 }
 
 #ifdef GRPC_ERROR_REFCOUNT_DEBUG
 void grpc_error_unref(grpc_error *err, const char *file, int line,
                       const char *func) {
-  if (is_special(err)) return;
+  if (grpc_error_is_special(err)) return;
   gpr_log(GPR_DEBUG, "%p: %" PRIdPTR " -> %" PRIdPTR " [%s:%d %s]", err,
           err->refs.count, err->refs.count - 1, file, line, func);
   if (gpr_unref(&err->refs)) {
@@ -212,7 +206,7 @@ void grpc_error_unref(grpc_error *err, const char *file, int line,
 }
 #else
 void grpc_error_unref(grpc_error *err) {
-  if (is_special(err)) return;
+  if (grpc_error_is_special(err)) return;
   if (gpr_unref(&err->refs)) {
     error_destroy(err);
   }
@@ -247,6 +241,7 @@ grpc_error *grpc_error_create(const char *file, int line, const char *desc,
   err->times = gpr_avl_add(gpr_avl_create(&avl_vtable_times),
                            (void *)(uintptr_t)GRPC_ERROR_TIME_CREATED,
                            box_time(gpr_now(GPR_CLOCK_REALTIME)));
+  gpr_atm_no_barrier_store(&err->error_string, 0);
   gpr_ref_init(&err->refs, 1);
   GPR_TIMER_END("grpc_error_create", 0);
   return err;
@@ -255,9 +250,10 @@ grpc_error *grpc_error_create(const char *file, int line, const char *desc,
 static grpc_error *copy_error_and_unref(grpc_error *in) {
   GPR_TIMER_BEGIN("copy_error_and_unref", 0);
   grpc_error *out;
-  if (is_special(in)) {
+  if (grpc_error_is_special(in)) {
     if (in == GRPC_ERROR_NONE)
-      out = GRPC_ERROR_CREATE("no error");
+      out = grpc_error_set_int(GRPC_ERROR_CREATE("no error"),
+                               GRPC_ERROR_INT_GRPC_STATUS, GRPC_STATUS_OK);
     else if (in == GRPC_ERROR_OOM)
       out = GRPC_ERROR_CREATE("oom");
     else if (in == GRPC_ERROR_CANCELLED)
@@ -275,6 +271,7 @@ static grpc_error *copy_error_and_unref(grpc_error *in) {
     out->strs = gpr_avl_ref(in->strs);
     out->errs = gpr_avl_ref(in->errs);
     out->times = gpr_avl_ref(in->times);
+    gpr_atm_no_barrier_store(&out->error_string, 0);
     out->next_err = in->next_err;
     gpr_ref_init(&out->refs, 1);
     GRPC_ERROR_UNREF(in);
@@ -292,14 +289,29 @@ grpc_error *grpc_error_set_int(grpc_error *src, grpc_error_ints which,
   return new;
 }
 
+typedef struct {
+  grpc_error *error;
+  grpc_status_code code;
+  const char *msg;
+} special_error_status_map;
+static special_error_status_map error_status_map[] = {
+    {GRPC_ERROR_NONE, GRPC_STATUS_OK, NULL},
+    {GRPC_ERROR_CANCELLED, GRPC_STATUS_CANCELLED, "Cancelled"},
+    {GRPC_ERROR_OOM, GRPC_STATUS_RESOURCE_EXHAUSTED, "Out of memory"},
+};
+
 bool grpc_error_get_int(grpc_error *err, grpc_error_ints which, intptr_t *p) {
   GPR_TIMER_BEGIN("grpc_error_get_int", 0);
   void *pp;
-  if (is_special(err)) {
-    if (err == GRPC_ERROR_CANCELLED && which == GRPC_ERROR_INT_GRPC_STATUS) {
-      *p = GRPC_STATUS_CANCELLED;
-      GPR_TIMER_END("grpc_error_get_int", 0);
-      return true;
+  if (grpc_error_is_special(err)) {
+    if (which == GRPC_ERROR_INT_GRPC_STATUS) {
+      for (size_t i = 0; i < GPR_ARRAY_SIZE(error_status_map); i++) {
+        if (error_status_map[i].error == err) {
+          if (p != NULL) *p = error_status_map[i].code;
+          GPR_TIMER_END("grpc_error_get_int", 0);
+          return true;
+        }
+      }
     }
     GPR_TIMER_END("grpc_error_get_int", 0);
     return false;
@@ -324,66 +336,17 @@ grpc_error *grpc_error_set_str(grpc_error *src, grpc_error_strs which,
 }
 
 const char *grpc_error_get_str(grpc_error *err, grpc_error_strs which) {
-  if (is_special(err)) return NULL;
-  return gpr_avl_get(err->strs, (void *)(uintptr_t)which);
-}
-
-typedef struct {
-  grpc_error *error;
-  grpc_status_code code;
-  const char *msg;
-} special_error_status_map;
-static special_error_status_map error_status_map[] = {
-    {GRPC_ERROR_NONE, GRPC_STATUS_OK, ""},
-    {GRPC_ERROR_CANCELLED, GRPC_STATUS_CANCELLED, "RPC cancelled"},
-    {GRPC_ERROR_OOM, GRPC_STATUS_RESOURCE_EXHAUSTED, "Out of memory"},
-};
-
-static grpc_error *recursively_find_error_with_status(grpc_error *error,
-                                                      intptr_t *status) {
-  // If the error itself has a status code, return it.
-  if (grpc_error_get_int(error, GRPC_ERROR_INT_GRPC_STATUS, status)) {
-    return error;
-  }
-  // Otherwise, search through its children.
-  intptr_t key = 0;
-  while (true) {
-    grpc_error *child_error = gpr_avl_get(error->errs, (void *)key++);
-    if (child_error == NULL) break;
-    grpc_error *result =
-        recursively_find_error_with_status(child_error, status);
-    if (result != NULL) return result;
-  }
-  return NULL;
-}
-
-void grpc_error_get_status(grpc_error *error, grpc_status_code *code,
-                           const char **msg) {
-  // Handle special errors via the static map.
-  for (size_t i = 0; i < GPR_ARRAY_SIZE(error_status_map); ++i) {
-    if (error == error_status_map[i].error) {
-      *code = error_status_map[i].code;
-      *msg = error_status_map[i].msg;
-      return;
+  if (grpc_error_is_special(err)) {
+    if (which == GRPC_ERROR_STR_GRPC_MESSAGE) {
+      for (size_t i = 0; i < GPR_ARRAY_SIZE(error_status_map); i++) {
+        if (error_status_map[i].error == err) {
+          return error_status_map[i].msg;
+        }
+      }
     }
+    return NULL;
   }
-  // Populate code.
-  // Start with the parent error and recurse through the tree of children
-  // until we find the first one that has a status code.
-  intptr_t status = GRPC_STATUS_UNKNOWN;  // Default in case we don't find one.
-  grpc_error *found_error = recursively_find_error_with_status(error, &status);
-  *code = (grpc_status_code)status;
-  // Now populate msg.
-  // If we found an error with a status code above, use that; otherwise,
-  // fall back to using the parent error.
-  if (found_error == NULL) found_error = error;
-  // If the error has a status message, use it.  Otherwise, fall back to
-  // the error description.
-  *msg = grpc_error_get_str(found_error, GRPC_ERROR_STR_GRPC_MESSAGE);
-  if (*msg == NULL) {
-    *msg = grpc_error_get_str(found_error, GRPC_ERROR_STR_DESCRIPTION);
-    if (*msg == NULL) *msg = "uknown error";  // Just in case.
-  }
+  return gpr_avl_get(err->strs, (void *)(uintptr_t)which);
 }
 
 grpc_error *grpc_error_add_child(grpc_error *src, grpc_error *child) {
@@ -535,7 +498,6 @@ static void add_errs(gpr_avl_node *n, char **s, size_t *sz, size_t *cap,
   *first = false;
   const char *e = grpc_error_string(n->value);
   append_str(e, s, sz, cap);
-  grpc_error_free_string(e);
   add_errs(n->right, s, sz, cap, first);
 }
 
@@ -557,7 +519,7 @@ static int cmp_kvs(const void *a, const void *b) {
   return strcmp(ka->key, kb->key);
 }
 
-static const char *finish_kvs(kv_pairs *kvs) {
+static char *finish_kvs(kv_pairs *kvs) {
   char *s = NULL;
   size_t sz = 0;
   size_t cap = 0;
@@ -578,19 +540,18 @@ static const char *finish_kvs(kv_pairs *kvs) {
   return s;
 }
 
-void grpc_error_free_string(const char *str) {
-  if (str == no_error_string) return;
-  if (str == oom_error_string) return;
-  if (str == cancelled_error_string) return;
-  gpr_free((char *)str);
-}
-
 const char *grpc_error_string(grpc_error *err) {
   GPR_TIMER_BEGIN("grpc_error_string", 0);
   if (err == GRPC_ERROR_NONE) return no_error_string;
   if (err == GRPC_ERROR_OOM) return oom_error_string;
   if (err == GRPC_ERROR_CANCELLED) return cancelled_error_string;
 
+  void *p = (void *)gpr_atm_acq_load(&err->error_string);
+  if (p != NULL) {
+    GPR_TIMER_END("grpc_error_string", 0);
+    return p;
+  }
+
   kv_pairs kvs;
   memset(&kvs, 0, sizeof(kvs));
 
@@ -603,7 +564,13 @@ const char *grpc_error_string(grpc_error *err) {
 
   qsort(kvs.kvs, kvs.num_kvs, sizeof(kv_pair), cmp_kvs);
 
-  const char *out = finish_kvs(&kvs);
+  char *out = finish_kvs(&kvs);
+
+  if (!gpr_atm_rel_cas(&err->error_string, 0, (gpr_atm)out)) {
+    gpr_free(out);
+    out = (char *)gpr_atm_no_barrier_load(&err->error_string);
+  }
+
   GPR_TIMER_END("grpc_error_string", 0);
   return out;
 }
@@ -638,7 +605,6 @@ bool grpc_log_if_error(const char *what, grpc_error *error, const char *file,
   if (error == GRPC_ERROR_NONE) return true;
   const char *msg = grpc_error_string(error);
   gpr_log(file, line, GPR_LOG_SEVERITY_ERROR, "%s: %s", what, msg);
-  grpc_error_free_string(msg);
   GRPC_ERROR_UNREF(error);
   return false;
 }

src/core/lib/iomgr/error.h

@@ -124,7 +124,11 @@ typedef enum {
   /// filename that we were trying to read/write when this error occurred
   GRPC_ERROR_STR_FILENAME,
   /// which data was queued for writing when the error occurred
-  GRPC_ERROR_STR_QUEUED_BUFFERS
+  GRPC_ERROR_STR_QUEUED_BUFFERS,
+  /// key associated with the error
+  GRPC_ERROR_STR_KEY,
+  /// value associated with the error
+  GRPC_ERROR_STR_VALUE,
 } grpc_error_strs;
 
 typedef enum {
@@ -141,7 +145,6 @@ typedef enum {
 #define GRPC_ERROR_CANCELLED ((grpc_error *)4)
 
 const char *grpc_error_string(grpc_error *error);
-void grpc_error_free_string(const char *str);
 
 /// Create an error - but use GRPC_ERROR_CREATE instead
 grpc_error *grpc_error_create(const char *file, int line, const char *desc,
@@ -189,12 +192,6 @@ grpc_error *grpc_error_set_str(grpc_error *src, grpc_error_strs which,
 /// Caller does NOT own return value.
 const char *grpc_error_get_str(grpc_error *error, grpc_error_strs which);
 
-/// A utility function to get the status code and message to be returned
-/// to the application.  If not set in the top-level message, looks
-/// through child errors until it finds the first one with these attributes.
-void grpc_error_get_status(grpc_error *error, grpc_status_code *code,
-                           const char **msg);
-
 /// Add a child error: an error that is believed to have contributed to this
 /// error occurring. Allows root causing high level errors from lower level
 /// errors that contributed to them.

src/core/lib/iomgr/error_internal.h

@@ -0,0 +1,54 @@
+/*
+ *
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef GRPC_CORE_LIB_IOMGR_ERROR_INTERNAL_H
+#define GRPC_CORE_LIB_IOMGR_ERROR_INTERNAL_H
+
+#include <inttypes.h>
+#include <stdbool.h>
+
+#include <grpc/support/avl.h>
+
+struct grpc_error {
+  gpr_refcount refs;
+  gpr_avl ints;
+  gpr_avl strs;
+  gpr_avl times;
+  gpr_avl errs;
+  uintptr_t next_err;
+  gpr_atm error_string;
+};
+
+bool grpc_error_is_special(grpc_error *err);
+
+#endif /* GRPC_CORE_LIB_IOMGR_ERROR_INTERNAL_H */

src/core/lib/iomgr/ev_epoll_linux.c

@@ -321,7 +321,7 @@ gpr_atm g_epoll_sync;
 #endif /* defined(GRPC_TSAN) */
 
 static const grpc_closure_scheduler_vtable workqueue_scheduler_vtable = {
-    workqueue_enqueue, workqueue_enqueue};
+    workqueue_enqueue, workqueue_enqueue, "workqueue"};
 
 static void pi_add_ref(polling_island *pi);
 static void pi_unref(grpc_exec_ctx *exec_ctx, polling_island *pi);

src/core/lib/iomgr/ev_posix.c

@@ -52,6 +52,8 @@
  *  tests */
 grpc_poll_function_type grpc_poll_function = poll;
 
+grpc_wakeup_fd grpc_global_wakeup_fd;
+
 static const grpc_event_engine_vtable *g_event_engine;
 static const char *g_poll_strategy_name = NULL;
 

src/core/lib/iomgr/exec_ctx.c

@@ -42,11 +42,16 @@
 #include "src/core/lib/profiling/timers.h"
 
 bool grpc_exec_ctx_ready_to_finish(grpc_exec_ctx *exec_ctx) {
-  if (!exec_ctx->cached_ready_to_finish) {
-    exec_ctx->cached_ready_to_finish = exec_ctx->check_ready_to_finish(
-        exec_ctx, exec_ctx->check_ready_to_finish_arg);
+  if ((exec_ctx->flags & GRPC_EXEC_CTX_FLAG_IS_FINISHED) == 0) {
+    if (exec_ctx->check_ready_to_finish(exec_ctx,
+                                        exec_ctx->check_ready_to_finish_arg)) {
+      exec_ctx->flags |= GRPC_EXEC_CTX_FLAG_IS_FINISHED;
+      return true;
+    }
+    return false;
+  } else {
+    return true;
   }
-  return exec_ctx->cached_ready_to_finish;
 }
 
 bool grpc_never_ready_to_finish(grpc_exec_ctx *exec_ctx, void *arg_ignored) {
@@ -82,7 +87,7 @@ bool grpc_exec_ctx_flush(grpc_exec_ctx *exec_ctx) {
 }
 
 void grpc_exec_ctx_finish(grpc_exec_ctx *exec_ctx) {
-  exec_ctx->cached_ready_to_finish = true;
+  exec_ctx->flags |= GRPC_EXEC_CTX_FLAG_IS_FINISHED;
   grpc_exec_ctx_flush(exec_ctx);
 }
 
@@ -101,6 +106,6 @@ void grpc_exec_ctx_global_init(void) {}
 void grpc_exec_ctx_global_shutdown(void) {}
 
 static const grpc_closure_scheduler_vtable exec_ctx_scheduler_vtable = {
-    exec_ctx_run, exec_ctx_sched};
+    exec_ctx_run, exec_ctx_sched, "exec_ctx"};
 static grpc_closure_scheduler exec_ctx_scheduler = {&exec_ctx_scheduler_vtable};
 grpc_closure_scheduler *grpc_schedule_on_exec_ctx = &exec_ctx_scheduler;

src/core/lib/iomgr/exec_ctx.h

@@ -43,6 +43,13 @@
 typedef struct grpc_workqueue grpc_workqueue;
 typedef struct grpc_combiner grpc_combiner;
 
+/* This exec_ctx is ready to return: either pre-populated, or cached as soon as
+   the finish_check returns true */
+#define GRPC_EXEC_CTX_FLAG_IS_FINISHED 1
+/* The exec_ctx's thread is (potentially) owned by a call or channel: care
+   should be given to not delete said call/channel from this exec_ctx */
+#define GRPC_EXEC_CTX_FLAG_THREAD_RESOURCE_LOOP 2
+
 /** Execution context.
  *  A bag of data that collects information along a callstack.
  *  Generally created at public API entry points, and passed down as
@@ -63,36 +70,26 @@ typedef struct grpc_combiner grpc_combiner;
  *  - Instances are always passed as the first argument to a function that
  *    takes it, and always as a pointer (grpc_exec_ctx is never copied).
  */
-#ifndef GRPC_EXECUTION_CONTEXT_SANITIZER
 struct grpc_exec_ctx {
   grpc_closure_list closure_list;
   /** currently active combiner: updated only via combiner.c */
   grpc_combiner *active_combiner;
   /** last active combiner in the active combiner list */
   grpc_combiner *last_combiner;
-  bool cached_ready_to_finish;
+  uintptr_t flags;
   void *check_ready_to_finish_arg;
   bool (*check_ready_to_finish)(grpc_exec_ctx *exec_ctx, void *arg);
 };
 
 /* initializer for grpc_exec_ctx:
    prefer to use GRPC_EXEC_CTX_INIT whenever possible */
-#define GRPC_EXEC_CTX_INIT_WITH_FINISH_CHECK(finish_check, finish_check_arg) \
-  { GRPC_CLOSURE_LIST_INIT, NULL, NULL, false, finish_check_arg, finish_check }
-#else
-struct grpc_exec_ctx {
-  bool cached_ready_to_finish;
-  void *check_ready_to_finish_arg;
-  bool (*check_ready_to_finish)(grpc_exec_ctx *exec_ctx, void *arg);
-};
-#define GRPC_EXEC_CTX_INIT_WITH_FINISH_CHECK(finish_check, finish_check_arg) \
-  { false, finish_check_arg, finish_check }
-#endif
+#define GRPC_EXEC_CTX_INITIALIZER(flags, finish_check, finish_check_arg) \
+  { GRPC_CLOSURE_LIST_INIT, NULL, NULL, flags, finish_check_arg, finish_check }
 
 /* initialize an execution context at the top level of an API call into grpc
    (this is safe to use elsewhere, though possibly not as efficient) */
 #define GRPC_EXEC_CTX_INIT \
-  GRPC_EXEC_CTX_INIT_WITH_FINISH_CHECK(grpc_always_ready_to_finish, NULL)
+  GRPC_EXEC_CTX_INITIALIZER(GRPC_EXEC_CTX_FLAG_IS_FINISHED, NULL, NULL)
 
 extern grpc_closure_scheduler *grpc_schedule_on_exec_ctx;
 

src/core/lib/iomgr/executor.c

@@ -158,7 +158,7 @@ void grpc_executor_shutdown(grpc_exec_ctx *exec_ctx) {
   gpr_mu_destroy(&g_executor.mu);
 }
 
-static const grpc_closure_scheduler_vtable executor_vtable = {executor_push,
-                                                              executor_push};
+static const grpc_closure_scheduler_vtable executor_vtable = {
+    executor_push, executor_push, "executor"};
 static grpc_closure_scheduler executor_scheduler = {&executor_vtable};
 grpc_closure_scheduler *grpc_executor_scheduler = &executor_scheduler;

src/core/lib/iomgr/load_file.c

@@ -47,7 +47,7 @@ grpc_error *grpc_load_file(const char *filename, int add_null_terminator,
                            grpc_slice *output) {
   unsigned char *contents = NULL;
   size_t contents_size = 0;
-  grpc_slice result = gpr_empty_slice();
+  grpc_slice result = grpc_empty_slice();
   FILE *file;
   size_t bytes_read = 0;
   grpc_error *error = GRPC_ERROR_NONE;

src/core/lib/iomgr/resource_quota.c

@@ -378,11 +378,15 @@ static void ru_slice_unref(grpc_exec_ctx *exec_ctx, void *p) {
   }
 }
 
+static const grpc_slice_refcount_vtable ru_slice_vtable = {
+    ru_slice_ref, ru_slice_unref, grpc_slice_default_eq_impl,
+    grpc_slice_default_hash_impl};
+
 static grpc_slice ru_slice_create(grpc_resource_user *resource_user,
                                   size_t size) {
   ru_slice_refcount *rc = gpr_malloc(sizeof(ru_slice_refcount) + size);
-  rc->base.ref = ru_slice_ref;
-  rc->base.unref = ru_slice_unref;
+  rc->base.vtable = &ru_slice_vtable;
+  rc->base.sub_refcount = &rc->base;
   gpr_ref_init(&rc->refs, 1);
   rc->resource_user = resource_user;
   rc->size = size;
@@ -691,6 +695,11 @@ grpc_resource_user *grpc_resource_user_create(
   return resource_user;
 }
 
+grpc_resource_quota *grpc_resource_user_quota(
+    grpc_resource_user *resource_user) {
+  return resource_user->resource_quota;
+}
+
 static void ru_ref_by(grpc_resource_user *resource_user, gpr_atm amount) {
   GPR_ASSERT(amount > 0);
   GPR_ASSERT(gpr_atm_no_barrier_fetch_add(&resource_user->refs, amount) != 0);

src/core/lib/iomgr/resource_quota.h

@@ -88,6 +88,12 @@ typedef struct grpc_resource_user grpc_resource_user;
 
 grpc_resource_user *grpc_resource_user_create(
     grpc_resource_quota *resource_quota, const char *name);
+
+/* Returns a borrowed reference to the underlying resource quota for this
+   resource user. */
+grpc_resource_quota *grpc_resource_user_quota(
+    grpc_resource_user *resource_user);
+
 void grpc_resource_user_ref(grpc_resource_user *resource_user);
 void grpc_resource_user_unref(grpc_exec_ctx *exec_ctx,
                               grpc_resource_user *resource_user);

src/core/lib/iomgr/tcp_client_posix.c

@@ -118,7 +118,6 @@ static void tc_on_alarm(grpc_exec_ctx *exec_ctx, void *acp, grpc_error *error) {
     const char *str = grpc_error_string(error);
     gpr_log(GPR_DEBUG, "CLIENT_CONNECT: %s: on_alarm: error=%s", ac->addr_str,
             str);
-    grpc_error_free_string(str);
   }
   gpr_mu_lock(&ac->mu);
   if (ac->fd != NULL) {
@@ -178,7 +177,6 @@ static void on_writable(grpc_exec_ctx *exec_ctx, void *acp, grpc_error *error) {
     const char *str = grpc_error_string(error);
     gpr_log(GPR_DEBUG, "CLIENT_CONNECT: %s: on_writable: error=%s",
             ac->addr_str, str);
-    grpc_error_free_string(str);
   }
 
   gpr_mu_lock(&ac->mu);

src/core/lib/iomgr/tcp_posix.c

@@ -181,7 +181,7 @@ static void call_read_cb(grpc_exec_ctx *exec_ctx, grpc_tcp *tcp,
     size_t i;
     const char *str = grpc_error_string(error);
     gpr_log(GPR_DEBUG, "read: error=%s", str);
-    grpc_error_free_string(str);
+
     for (i = 0; i < tcp->incoming_buffer->count; i++) {
       char *dump = grpc_dump_slice(tcp->incoming_buffer->slices[i],
                                    GPR_DUMP_HEX | GPR_DUMP_ASCII);
@@ -435,7 +435,6 @@ static void tcp_handle_write(grpc_exec_ctx *exec_ctx, void *arg /* grpc_tcp */,
     if (grpc_tcp_trace) {
       const char *str = grpc_error_string(error);
       gpr_log(GPR_DEBUG, "write: %s", str);
-      grpc_error_free_string(str);
     }
 
     grpc_closure_run(exec_ctx, cb, error);
@@ -485,7 +484,6 @@ static void tcp_write(grpc_exec_ctx *exec_ctx, grpc_endpoint *ep,
     if (grpc_tcp_trace) {
       const char *str = grpc_error_string(error);
       gpr_log(GPR_DEBUG, "write: %s", str);
-      grpc_error_free_string(str);
     }
     grpc_closure_sched(exec_ctx, cb, error);
   }

src/core/lib/iomgr/tcp_server_windows.c

@@ -343,7 +343,7 @@ static void on_accept(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) {
   if (error != GRPC_ERROR_NONE) {
     const char *msg = grpc_error_string(error);
     gpr_log(GPR_INFO, "Skipping on_accept due to error: %s", msg);
-    grpc_error_free_string(msg);
+
     gpr_mu_unlock(&sp->server->mu);
     return;
   }

src/core/lib/iomgr/tcp_uv.c

@@ -48,6 +48,7 @@
 #include "src/core/lib/iomgr/network_status_tracker.h"
 #include "src/core/lib/iomgr/resource_quota.h"
 #include "src/core/lib/iomgr/tcp_uv.h"
+#include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/slice/slice_string_helpers.h"
 #include "src/core/lib/support/string.h"
 
@@ -156,7 +157,7 @@ static void read_callback(uv_stream_t *stream, ssize_t nread,
       size_t i;
       const char *str = grpc_error_string(error);
       gpr_log(GPR_DEBUG, "read: error=%s", str);
-      grpc_error_free_string(str);
+
       for (i = 0; i < tcp->read_slices->count; i++) {
         char *dump = grpc_dump_slice(tcp->read_slices->slices[i],
                                      GPR_DUMP_HEX | GPR_DUMP_ASCII);

src/core/lib/security/credentials/google_default/google_default_credentials.c

@@ -177,7 +177,7 @@ static grpc_error *create_default_creds_from_path(
   grpc_auth_json_key key;
   grpc_auth_refresh_token token;
   grpc_call_credentials *result = NULL;
-  grpc_slice creds_data = gpr_empty_slice();
+  grpc_slice creds_data = grpc_empty_slice();
   grpc_error *error = GRPC_ERROR_NONE;
   if (creds_path == NULL) {
     error = GRPC_ERROR_CREATE("creds_path unset");

src/core/lib/security/credentials/plugin/plugin_credentials.c

@@ -42,7 +42,9 @@
 #include <grpc/support/sync.h>
 
 #include "src/core/lib/slice/slice_internal.h"
+#include "src/core/lib/slice/slice_string_helpers.h"
 #include "src/core/lib/surface/api_trace.h"
+#include "src/core/lib/surface/validate_metadata.h"
 
 typedef struct {
   void *user_data;
@@ -63,7 +65,9 @@ static void plugin_md_request_metadata_ready(void *request,
                                              grpc_status_code status,
                                              const char *error_details) {
   /* called from application code */
-  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INITIALIZER(
+      GRPC_EXEC_CTX_FLAG_IS_FINISHED | GRPC_EXEC_CTX_FLAG_THREAD_RESOURCE_LOOP,
+      NULL, NULL);
   grpc_metadata_plugin_request *r = (grpc_metadata_plugin_request *)request;
   if (status != GRPC_STATUS_OK) {
     if (error_details != NULL) {
@@ -77,13 +81,14 @@ static void plugin_md_request_metadata_ready(void *request,
     bool seen_illegal_header = false;
     grpc_credentials_md *md_array = NULL;
     for (i = 0; i < num_md; i++) {
-      if (!grpc_header_key_is_legal(md[i].key, strlen(md[i].key))) {
-        gpr_log(GPR_ERROR, "Plugin added invalid metadata key: %s", md[i].key);
+      if (!GRPC_LOG_IF_ERROR("validate_metadata_from_plugin",
+                             grpc_validate_header_key_is_legal(md[i].key))) {
         seen_illegal_header = true;
         break;
-      } else if (!grpc_is_binary_header(md[i].key, strlen(md[i].key)) &&
-                 !grpc_header_nonbin_value_is_legal(md[i].value,
-                                                    md[i].value_length)) {
+      } else if (!grpc_is_binary_header(md[i].key) &&
+                 !GRPC_LOG_IF_ERROR(
+                     "validate_metadata_from_plugin",
+                     grpc_validate_header_nonbin_value_is_legal(md[i].value))) {
         gpr_log(GPR_ERROR, "Plugin added invalid metadata value.");
         seen_illegal_header = true;
         break;
@@ -95,9 +100,8 @@ static void plugin_md_request_metadata_ready(void *request,
     } else if (num_md > 0) {
       md_array = gpr_malloc(num_md * sizeof(grpc_credentials_md));
       for (i = 0; i < num_md; i++) {
-        md_array[i].key = grpc_slice_from_copied_string(md[i].key);
-        md_array[i].value =
-            grpc_slice_from_copied_buffer(md[i].value, md[i].value_length);
+        md_array[i].key = grpc_slice_ref_internal(md[i].key);
+        md_array[i].value = grpc_slice_ref_internal(md[i].value);
       }
       r->cb(&exec_ctx, r->user_data, md_array, num_md, GRPC_CREDENTIALS_OK,
             NULL);

src/core/lib/security/transport/client_auth_filter.c

@@ -45,6 +45,7 @@
 #include "src/core/lib/security/credentials/credentials.h"
 #include "src/core/lib/security/transport/security_connector.h"
 #include "src/core/lib/slice/slice_internal.h"
+#include "src/core/lib/slice/slice_string_helpers.h"
 #include "src/core/lib/support/string.h"
 #include "src/core/lib/surface/call.h"
 #include "src/core/lib/transport/static_metadata.h"
@@ -54,8 +55,10 @@
 /* We can have a per-call credentials. */
 typedef struct {
   grpc_call_credentials *creds;
-  grpc_mdstr *host;
-  grpc_mdstr *method;
+  bool have_host;
+  bool have_method;
+  grpc_slice host;
+  grpc_slice method;
   /* pollset{_set} bound to this call; if we need to make external
      network requests, they should be done under a pollset added to this
      pollset_set so that work can progress when this call wants work to progress
@@ -89,14 +92,12 @@ static void reset_auth_metadata_context(
   auth_md_context->channel_auth_context = NULL;
 }
 
-static void bubble_up_error(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
-                            grpc_status_code status, const char *error_msg) {
-  call_data *calld = elem->call_data;
-  gpr_log(GPR_ERROR, "Client side authentication failure: %s", error_msg);
-  grpc_slice error_slice = grpc_slice_from_copied_string(error_msg);
-  grpc_transport_stream_op_add_close(exec_ctx, &calld->op, status,
-                                     &error_slice);
-  grpc_call_next_op(exec_ctx, elem, &calld->op);
+static void add_error(grpc_error **combined, grpc_error *error) {
+  if (error == GRPC_ERROR_NONE) return;
+  if (*combined == GRPC_ERROR_NONE) {
+    *combined = GRPC_ERROR_CREATE("Client auth metadata plugin error");
+  }
+  *combined = grpc_error_add_child(*combined, error);
 }
 
 static void on_credentials_metadata(grpc_exec_ctx *exec_ctx, void *user_data,
@@ -110,30 +111,37 @@ static void on_credentials_metadata(grpc_exec_ctx *exec_ctx, void *user_data,
   grpc_metadata_batch *mdb;
   size_t i;
   reset_auth_metadata_context(&calld->auth_md_context);
+  grpc_error *error = GRPC_ERROR_NONE;
   if (status != GRPC_CREDENTIALS_OK) {
-    bubble_up_error(exec_ctx, elem, GRPC_STATUS_UNAUTHENTICATED,
-                    (error_details != NULL && strlen(error_details) > 0)
-                        ? error_details
-                        : "Credentials failed to get metadata.");
-    return;
+    error = grpc_error_set_int(
+        GRPC_ERROR_CREATE(error_details != NULL && strlen(error_details) > 0
+                              ? error_details
+                              : "Credentials failed to get metadata."),
+        GRPC_ERROR_INT_GRPC_STATUS, GRPC_STATUS_UNAUTHENTICATED);
+  } else {
+    GPR_ASSERT(num_md <= MAX_CREDENTIALS_METADATA_COUNT);
+    GPR_ASSERT(op->send_initial_metadata != NULL);
+    mdb = op->send_initial_metadata;
+    for (i = 0; i < num_md; i++) {
+      add_error(&error,
+                grpc_metadata_batch_add_tail(
+                    exec_ctx, mdb, &calld->md_links[i],
+                    grpc_mdelem_from_slices(
+                        exec_ctx, grpc_slice_ref_internal(md_elems[i].key),
+                        grpc_slice_ref_internal(md_elems[i].value))));
+    }
   }
-  GPR_ASSERT(num_md <= MAX_CREDENTIALS_METADATA_COUNT);
-  GPR_ASSERT(op->send_initial_metadata != NULL);
-  mdb = op->send_initial_metadata;
-  for (i = 0; i < num_md; i++) {
-    grpc_metadata_batch_add_tail(
-        mdb, &calld->md_links[i],
-        grpc_mdelem_from_slices(exec_ctx,
-                                grpc_slice_ref_internal(md_elems[i].key),
-                                grpc_slice_ref_internal(md_elems[i].value)));
+  if (error == GRPC_ERROR_NONE) {
+    grpc_call_next_op(exec_ctx, elem, op);
+  } else {
+    grpc_transport_stream_op_finish_with_failure(exec_ctx, op, error);
   }
-  grpc_call_next_op(exec_ctx, elem, op);
 }
 
 void build_auth_metadata_context(grpc_security_connector *sc,
                                  grpc_auth_context *auth_context,
                                  call_data *calld) {
-  char *service = gpr_strdup(grpc_mdstr_as_c_string(calld->method));
+  char *service = grpc_slice_to_c_string(calld->method);
   char *last_slash = strrchr(service, '/');
   char *method_name = NULL;
   char *service_url = NULL;
@@ -149,14 +157,15 @@ void build_auth_metadata_context(grpc_security_connector *sc,
     method_name = gpr_strdup(last_slash + 1);
   }
   if (method_name == NULL) method_name = gpr_strdup("");
+  char *host = grpc_slice_to_c_string(calld->host);
   gpr_asprintf(&service_url, "%s://%s%s",
-               sc->url_scheme == NULL ? "" : sc->url_scheme,
-               grpc_mdstr_as_c_string(calld->host), service);
+               sc->url_scheme == NULL ? "" : sc->url_scheme, host, service);
   calld->auth_md_context.service_url = service_url;
   calld->auth_md_context.method_name = method_name;
   calld->auth_md_context.channel_auth_context =
       GRPC_AUTH_CONTEXT_REF(auth_context, "grpc_auth_metadata_context");
   gpr_free(service);
+  gpr_free(host);
 }
 
 static void send_security_metadata(grpc_exec_ctx *exec_ctx,
@@ -180,8 +189,12 @@ static void send_security_metadata(grpc_exec_ctx *exec_ctx,
     calld->creds = grpc_composite_call_credentials_create(channel_call_creds,
                                                           ctx->creds, NULL);
     if (calld->creds == NULL) {
-      bubble_up_error(exec_ctx, elem, GRPC_STATUS_UNAUTHENTICATED,
-                      "Incompatible credentials set on channel and call.");
+      grpc_transport_stream_op_finish_with_failure(
+          exec_ctx, op,
+          grpc_error_set_int(
+              GRPC_ERROR_CREATE(
+                  "Incompatible credentials set on channel and call."),
+              GRPC_ERROR_INT_GRPC_STATUS, GRPC_STATUS_UNAUTHENTICATED));
       return;
     }
   } else {
@@ -207,9 +220,14 @@ static void on_host_checked(grpc_exec_ctx *exec_ctx, void *user_data,
     send_security_metadata(exec_ctx, elem, &calld->op);
   } else {
     char *error_msg;
+    char *host = grpc_slice_to_c_string(calld->host);
     gpr_asprintf(&error_msg, "Invalid host %s set in :authority metadata.",
-                 grpc_mdstr_as_c_string(calld->host));
-    bubble_up_error(exec_ctx, elem, GRPC_STATUS_UNAUTHENTICATED, error_msg);
+                 host);
+    gpr_free(host);
+    grpc_call_element_signal_error(
+        exec_ctx, elem, grpc_error_set_int(GRPC_ERROR_CREATE(error_msg),
+                                           GRPC_ERROR_INT_GRPC_STATUS,
+                                           GRPC_STATUS_UNAUTHENTICATED));
     gpr_free(error_msg);
   }
 }
@@ -247,23 +265,30 @@ static void auth_start_transport_op(grpc_exec_ctx *exec_ctx,
 
   if (op->send_initial_metadata != NULL) {
     for (l = op->send_initial_metadata->list.head; l != NULL; l = l->next) {
-      grpc_mdelem *md = l->md;
+      grpc_mdelem md = l->md;
       /* Pointer comparison is OK for md_elems created from the same context.
        */
-      if (md->key == GRPC_MDSTR_AUTHORITY) {
-        if (calld->host != NULL) GRPC_MDSTR_UNREF(exec_ctx, calld->host);
-        calld->host = GRPC_MDSTR_REF(md->value);
-      } else if (md->key == GRPC_MDSTR_PATH) {
-        if (calld->method != NULL) GRPC_MDSTR_UNREF(exec_ctx, calld->method);
-        calld->method = GRPC_MDSTR_REF(md->value);
+      if (grpc_slice_eq(GRPC_MDKEY(md), GRPC_MDSTR_AUTHORITY)) {
+        if (calld->have_host) {
+          grpc_slice_unref_internal(exec_ctx, calld->host);
+        }
+        calld->host = grpc_slice_ref_internal(GRPC_MDVALUE(md));
+        calld->have_host = true;
+      } else if (grpc_slice_eq(GRPC_MDKEY(md), GRPC_MDSTR_PATH)) {
+        if (calld->have_method) {
+          grpc_slice_unref_internal(exec_ctx, calld->method);
+        }
+        calld->method = grpc_slice_ref_internal(GRPC_MDVALUE(md));
+        calld->have_method = true;
       }
     }
-    if (calld->host != NULL) {
-      const char *call_host = grpc_mdstr_as_c_string(calld->host);
+    if (calld->have_host) {
+      char *call_host = grpc_slice_to_c_string(calld->host);
       calld->op = *op; /* Copy op (originates from the caller's stack). */
       grpc_channel_security_connector_check_call_host(
           exec_ctx, chand->security_connector, call_host, chand->auth_context,
           on_host_checked, elem);
+      gpr_free(call_host);
       GPR_TIMER_END("auth_start_transport_op", 0);
       return; /* early exit */
     }
@@ -296,11 +321,11 @@ static void destroy_call_elem(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
                               void *ignored) {
   call_data *calld = elem->call_data;
   grpc_call_credentials_unref(exec_ctx, calld->creds);
-  if (calld->host != NULL) {
-    GRPC_MDSTR_UNREF(exec_ctx, calld->host);
+  if (calld->have_host) {
+    grpc_slice_unref_internal(exec_ctx, calld->host);
   }
-  if (calld->method != NULL) {
-    GRPC_MDSTR_UNREF(exec_ctx, calld->method);
+  if (calld->have_method) {
+    grpc_slice_unref_internal(exec_ctx, calld->method);
   }
   reset_auth_metadata_context(&calld->auth_md_context);
 }

src/core/lib/security/transport/security_connector.c

@@ -601,7 +601,7 @@ static grpc_security_connector_vtable ssl_server_vtable = {
     ssl_server_destroy, ssl_server_check_peer};
 
 static grpc_slice compute_default_pem_root_certs_once(void) {
-  grpc_slice result = gpr_empty_slice();
+  grpc_slice result = grpc_empty_slice();
 
   /* First try to load the roots from the environment. */
   char *default_root_certs_path =

src/core/lib/security/transport/security_handshaker.c

@@ -124,7 +124,7 @@ static void security_handshake_failed_locked(grpc_exec_ctx *exec_ctx,
   }
   const char *msg = grpc_error_string(error);
   gpr_log(GPR_DEBUG, "Security handshake failed: %s", msg);
-  grpc_error_free_string(msg);
+
   if (!h->shutdown) {
     // TODO(ctiller): It is currently necessary to shutdown endpoints
     // before destroying them, even if we know that there are no

src/core/lib/security/transport/server_auth_filter.c

@@ -33,12 +33,13 @@
 
 #include <string.h>
 
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+
 #include "src/core/lib/security/context/security_context.h"
 #include "src/core/lib/security/credentials/credentials.h"
 #include "src/core/lib/security/transport/auth_filters.h"
-
-#include <grpc/support/alloc.h>
-#include <grpc/support/log.h>
+#include "src/core/lib/slice/slice_internal.h"
 
 typedef struct call_data {
   grpc_metadata_batch *recv_initial_metadata;
@@ -67,48 +68,34 @@ static grpc_metadata_array metadata_batch_to_md_array(
   grpc_metadata_array_init(&result);
   for (l = batch->list.head; l != NULL; l = l->next) {
     grpc_metadata *usr_md = NULL;
-    grpc_mdelem *md = l->md;
-    grpc_mdstr *key = md->key;
-    grpc_mdstr *value = md->value;
+    grpc_mdelem md = l->md;
+    grpc_slice key = GRPC_MDKEY(md);
+    grpc_slice value = GRPC_MDVALUE(md);
     if (result.count == result.capacity) {
       result.capacity = GPR_MAX(result.capacity + 8, result.capacity * 2);
       result.metadata =
           gpr_realloc(result.metadata, result.capacity * sizeof(grpc_metadata));
     }
     usr_md = &result.metadata[result.count++];
-    usr_md->key = grpc_mdstr_as_c_string(key);
-    usr_md->value = grpc_mdstr_as_c_string(value);
-    usr_md->value_length = GRPC_SLICE_LENGTH(value->slice);
+    usr_md->key = grpc_slice_ref_internal(key);
+    usr_md->value = grpc_slice_ref_internal(value);
   }
   return result;
 }
 
-static grpc_mdelem *remove_consumed_md(grpc_exec_ctx *exec_ctx, void *user_data,
-                                       grpc_mdelem *md) {
+static grpc_filtered_mdelem remove_consumed_md(grpc_exec_ctx *exec_ctx,
+                                               void *user_data,
+                                               grpc_mdelem md) {
   grpc_call_element *elem = user_data;
   call_data *calld = elem->call_data;
   size_t i;
   for (i = 0; i < calld->num_consumed_md; i++) {
     const grpc_metadata *consumed_md = &calld->consumed_md[i];
-    /* Maybe we could do a pointer comparison but we do not have any guarantee
-       that the metadata processor used the same pointers for consumed_md in the
-       callback. */
-    if (GRPC_SLICE_LENGTH(md->key->slice) != strlen(consumed_md->key) ||
-        GRPC_SLICE_LENGTH(md->value->slice) != consumed_md->value_length) {
-      continue;
-    }
-    if (memcmp(GRPC_SLICE_START_PTR(md->key->slice), consumed_md->key,
-               GRPC_SLICE_LENGTH(md->key->slice)) == 0 &&
-        memcmp(GRPC_SLICE_START_PTR(md->value->slice), consumed_md->value,
-               GRPC_SLICE_LENGTH(md->value->slice)) == 0) {
-      return NULL; /* Delete. */
-    }
+    if (grpc_slice_eq(GRPC_MDKEY(md), consumed_md->key) &&
+        grpc_slice_eq(GRPC_MDVALUE(md), consumed_md->value))
+      return GRPC_FILTERED_REMOVE();
   }
-  return md;
-}
-
-static void destroy_op(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) {
-  gpr_free(arg);
+  return GRPC_FILTERED_MDELEM(md);
 }
 
 /* called from application code */
@@ -130,29 +117,33 @@ static void on_md_processing_done(
   if (status == GRPC_STATUS_OK) {
     calld->consumed_md = consumed_md;
     calld->num_consumed_md = num_consumed_md;
-    grpc_metadata_batch_filter(&exec_ctx, calld->recv_initial_metadata,
-                               remove_consumed_md, elem);
+    /* TODO(ctiller): propagate error */
+    GRPC_LOG_IF_ERROR(
+        "grpc_metadata_batch_filter",
+        grpc_metadata_batch_filter(&exec_ctx, calld->recv_initial_metadata,
+                                   remove_consumed_md, elem,
+                                   "Response metadata filtering error"));
+    for (size_t i = 0; i < calld->md.count; i++) {
+      grpc_slice_unref_internal(&exec_ctx, calld->md.metadata[i].key);
+      grpc_slice_unref_internal(&exec_ctx, calld->md.metadata[i].value);
+    }
     grpc_metadata_array_destroy(&calld->md);
     grpc_closure_sched(&exec_ctx, calld->on_done_recv, GRPC_ERROR_NONE);
   } else {
-    grpc_slice message;
-    grpc_transport_stream_op *close_op = gpr_malloc(sizeof(*close_op));
-    memset(close_op, 0, sizeof(*close_op));
+    for (size_t i = 0; i < calld->md.count; i++) {
+      grpc_slice_unref_internal(&exec_ctx, calld->md.metadata[i].key);
+      grpc_slice_unref_internal(&exec_ctx, calld->md.metadata[i].value);
+    }
     grpc_metadata_array_destroy(&calld->md);
     error_details = error_details != NULL
                         ? error_details
                         : "Authentication metadata processing failed.";
-    message = grpc_slice_from_copied_string(error_details);
     calld->transport_op->send_initial_metadata = NULL;
     if (calld->transport_op->send_message != NULL) {
       grpc_byte_stream_destroy(&exec_ctx, calld->transport_op->send_message);
       calld->transport_op->send_message = NULL;
     }
     calld->transport_op->send_trailing_metadata = NULL;
-    close_op->on_complete =
-        grpc_closure_create(destroy_op, close_op, grpc_schedule_on_exec_ctx);
-    grpc_transport_stream_op_add_close(&exec_ctx, close_op, status, &message);
-    grpc_call_next_op(&exec_ctx, elem, close_op);
     grpc_closure_sched(&exec_ctx, calld->on_done_recv,
                        grpc_error_set_int(GRPC_ERROR_CREATE(error_details),
                                           GRPC_ERROR_INT_GRPC_STATUS, status));

src/core/lib/security/util/b64.c

@@ -232,5 +232,5 @@ grpc_slice grpc_base64_decode_with_len(grpc_exec_ctx *exec_ctx, const char *b64,
 
 fail:
   grpc_slice_unref_internal(exec_ctx, result);
-  return gpr_empty_slice();
+  return grpc_empty_slice();
 }

src/core/lib/slice/slice.c

@@ -41,23 +41,30 @@
 
 #include "src/core/lib/iomgr/exec_ctx.h"
 
-grpc_slice gpr_empty_slice(void) {
+char *grpc_slice_to_c_string(grpc_slice slice) {
+  char *out = gpr_malloc(GRPC_SLICE_LENGTH(slice) + 1);
+  memcpy(out, GRPC_SLICE_START_PTR(slice), GRPC_SLICE_LENGTH(slice));
+  out[GRPC_SLICE_LENGTH(slice)] = 0;
+  return out;
+}
+
+grpc_slice grpc_empty_slice(void) {
   grpc_slice out;
-  out.refcount = 0;
+  out.refcount = NULL;
   out.data.inlined.length = 0;
   return out;
 }
 
 grpc_slice grpc_slice_ref_internal(grpc_slice slice) {
   if (slice.refcount) {
-    slice.refcount->ref(slice.refcount);
+    slice.refcount->vtable->ref(slice.refcount);
   }
   return slice;
 }
 
 void grpc_slice_unref_internal(grpc_exec_ctx *exec_ctx, grpc_slice slice) {
   if (slice.refcount) {
-    slice.refcount->unref(exec_ctx, slice.refcount);
+    slice.refcount->vtable->unref(exec_ctx, slice.refcount);
   }
 }
 
@@ -78,16 +85,24 @@ void grpc_slice_unref(grpc_slice slice) {
 static void noop_ref(void *unused) {}
 static void noop_unref(grpc_exec_ctx *exec_ctx, void *unused) {}
 
-static grpc_slice_refcount noop_refcount = {noop_ref, noop_unref};
+static const grpc_slice_refcount_vtable noop_refcount_vtable = {
+    noop_ref, noop_unref, grpc_slice_default_eq_impl,
+    grpc_slice_default_hash_impl};
+static grpc_slice_refcount noop_refcount = {&noop_refcount_vtable,
+                                            &noop_refcount};
 
-grpc_slice grpc_slice_from_static_string(const char *s) {
+grpc_slice grpc_slice_from_static_buffer(const void *s, size_t len) {
   grpc_slice slice;
   slice.refcount = &noop_refcount;
   slice.data.refcounted.bytes = (uint8_t *)s;
-  slice.data.refcounted.length = strlen(s);
+  slice.data.refcounted.length = len;
   return slice;
 }
 
+grpc_slice grpc_slice_from_static_string(const char *s) {
+  return grpc_slice_from_static_buffer(s, strlen(s));
+}
+
 /* grpc_slice_new support structures - we create a refcount object extended
    with the user provided data pointer & destroy function */
 typedef struct new_slice_refcount {
@@ -110,14 +125,18 @@ static void new_slice_unref(grpc_exec_ctx *exec_ctx, void *p) {
   }
 }
 
+static const grpc_slice_refcount_vtable new_slice_vtable = {
+    new_slice_ref, new_slice_unref, grpc_slice_default_eq_impl,
+    grpc_slice_default_hash_impl};
+
 grpc_slice grpc_slice_new_with_user_data(void *p, size_t len,
                                          void (*destroy)(void *),
                                          void *user_data) {
   grpc_slice slice;
   new_slice_refcount *rc = gpr_malloc(sizeof(new_slice_refcount));
   gpr_ref_init(&rc->refs, 1);
-  rc->rc.ref = new_slice_ref;
-  rc->rc.unref = new_slice_unref;
+  rc->rc.vtable = &new_slice_vtable;
+  rc->rc.sub_refcount = &rc->rc;
   rc->user_destroy = destroy;
   rc->user_data = user_data;
 
@@ -155,14 +174,18 @@ static void new_with_len_unref(grpc_exec_ctx *exec_ctx, void *p) {
   }
 }
 
+static const grpc_slice_refcount_vtable new_with_len_vtable = {
+    new_with_len_ref, new_with_len_unref, grpc_slice_default_eq_impl,
+    grpc_slice_default_hash_impl};
+
 grpc_slice grpc_slice_new_with_len(void *p, size_t len,
                                    void (*destroy)(void *, size_t)) {
   grpc_slice slice;
   new_with_len_slice_refcount *rc =
       gpr_malloc(sizeof(new_with_len_slice_refcount));
   gpr_ref_init(&rc->refs, 1);
-  rc->rc.ref = new_with_len_ref;
-  rc->rc.unref = new_with_len_unref;
+  rc->rc.vtable = &new_with_len_vtable;
+  rc->rc.sub_refcount = &rc->rc;
   rc->user_destroy = destroy;
   rc->user_data = p;
   rc->user_length = len;
@@ -200,6 +223,10 @@ static void malloc_unref(grpc_exec_ctx *exec_ctx, void *p) {
   }
 }
 
+static const grpc_slice_refcount_vtable malloc_vtable = {
+    malloc_ref, malloc_unref, grpc_slice_default_eq_impl,
+    grpc_slice_default_hash_impl};
+
 grpc_slice grpc_slice_malloc(size_t length) {
   grpc_slice slice;
 
@@ -219,8 +246,8 @@ grpc_slice grpc_slice_malloc(size_t length) {
        this reference. */
     gpr_ref_init(&rc->refs, 1);
 
-    rc->base.ref = malloc_ref;
-    rc->base.unref = malloc_unref;
+    rc->base.vtable = &malloc_vtable;
+    rc->base.sub_refcount = &rc->base;
 
     /* Build up the slice to be returned. */
     /* The slices refcount points back to the allocated block. */
@@ -247,7 +274,7 @@ grpc_slice grpc_slice_sub_no_ref(grpc_slice source, size_t begin, size_t end) {
     GPR_ASSERT(source.data.refcounted.length >= end);
 
     /* Build the result */
-    subset.refcount = source.refcount;
+    subset.refcount = source.refcount->sub_refcount;
     /* Point into the source array */
     subset.data.refcounted.bytes = source.data.refcounted.bytes + begin;
     subset.data.refcounted.length = end - begin;
@@ -273,7 +300,7 @@ grpc_slice grpc_slice_sub(grpc_slice source, size_t begin, size_t end) {
   } else {
     subset = grpc_slice_sub_no_ref(source, begin, end);
     /* Bump the refcount */
-    subset.refcount->ref(subset.refcount);
+    subset.refcount->vtable->ref(subset.refcount);
   }
   return subset;
 }
@@ -300,13 +327,14 @@ grpc_slice grpc_slice_split_tail(grpc_slice *source, size_t split) {
              tail_length);
     } else {
       /* Build the result */
-      tail.refcount = source->refcount;
+      tail.refcount = source->refcount->sub_refcount;
       /* Bump the refcount */
-      tail.refcount->ref(tail.refcount);
+      tail.refcount->vtable->ref(tail.refcount);
       /* Point into the source array */
       tail.data.refcounted.bytes = source->data.refcounted.bytes + split;
       tail.data.refcounted.length = tail_length;
     }
+    source->refcount = source->refcount->sub_refcount;
     source->data.refcounted.length = split;
   }
 
@@ -332,18 +360,20 @@ grpc_slice grpc_slice_split_head(grpc_slice *source, size_t split) {
     head.refcount = NULL;
     head.data.inlined.length = (uint8_t)split;
     memcpy(head.data.inlined.bytes, source->data.refcounted.bytes, split);
+    source->refcount = source->refcount->sub_refcount;
     source->data.refcounted.bytes += split;
     source->data.refcounted.length -= split;
   } else {
     GPR_ASSERT(source->data.refcounted.length >= split);
 
     /* Build the result */
-    head.refcount = source->refcount;
+    head.refcount = source->refcount->sub_refcount;
     /* Bump the refcount */
-    head.refcount->ref(head.refcount);
+    head.refcount->vtable->ref(head.refcount);
     /* Point into the source array */
     head.data.refcounted.bytes = source->data.refcounted.bytes;
     head.data.refcounted.length = split;
+    source->refcount = source->refcount->sub_refcount;
     source->data.refcounted.bytes += split;
     source->data.refcounted.length -= split;
   }
@@ -351,6 +381,19 @@ grpc_slice grpc_slice_split_head(grpc_slice *source, size_t split) {
   return head;
 }
 
+int grpc_slice_default_eq_impl(grpc_slice a, grpc_slice b) {
+  return GRPC_SLICE_LENGTH(a) == GRPC_SLICE_LENGTH(b) &&
+         0 == memcmp(GRPC_SLICE_START_PTR(a), GRPC_SLICE_START_PTR(b),
+                     GRPC_SLICE_LENGTH(a));
+}
+
+int grpc_slice_eq(grpc_slice a, grpc_slice b) {
+  if (a.refcount && b.refcount && a.refcount->vtable == b.refcount->vtable) {
+    return a.refcount->vtable->eq(a, b);
+  }
+  return grpc_slice_default_eq_impl(a, b);
+}
+
 int grpc_slice_cmp(grpc_slice a, grpc_slice b) {
   int d = (int)(GRPC_SLICE_LENGTH(a) - GRPC_SLICE_LENGTH(b));
   if (d != 0) return d;
@@ -367,8 +410,55 @@ int grpc_slice_str_cmp(grpc_slice a, const char *b) {
 
 int grpc_slice_is_equivalent(grpc_slice a, grpc_slice b) {
   if (a.refcount == NULL || b.refcount == NULL) {
-    return grpc_slice_cmp(a, b) == 0;
+    return grpc_slice_eq(a, b);
   }
   return a.data.refcounted.length == b.data.refcounted.length &&
          a.data.refcounted.bytes == b.data.refcounted.bytes;
 }
+
+int grpc_slice_buf_start_eq(grpc_slice a, const void *b, size_t len) {
+  if (GRPC_SLICE_LENGTH(a) < len) return 0;
+  return 0 == memcmp(GRPC_SLICE_START_PTR(a), b, len);
+}
+
+int grpc_slice_rchr(grpc_slice s, char c) {
+  const char *b = (const char *)GRPC_SLICE_START_PTR(s);
+  int i;
+  for (i = (int)GRPC_SLICE_LENGTH(s) - 1; i != -1 && b[i] != c; i--)
+    ;
+  return i;
+}
+
+int grpc_slice_chr(grpc_slice s, char c) {
+  const char *b = (const char *)GRPC_SLICE_START_PTR(s);
+  const char *p = memchr(b, c, GRPC_SLICE_LENGTH(s));
+  return p == NULL ? -1 : (int)(p - b);
+}
+
+int grpc_slice_slice(grpc_slice haystack, grpc_slice needle) {
+  size_t haystack_len = GRPC_SLICE_LENGTH(haystack);
+  const uint8_t *haystack_bytes = GRPC_SLICE_START_PTR(haystack);
+  size_t needle_len = GRPC_SLICE_LENGTH(needle);
+  const uint8_t *needle_bytes = GRPC_SLICE_START_PTR(needle);
+
+  if (haystack_len == 0 || needle_len == 0) return -1;
+  if (haystack_len < needle_len) return -1;
+  if (haystack_len == needle_len)
+    return grpc_slice_eq(haystack, needle) ? 0 : -1;
+  if (needle_len == 1) return grpc_slice_chr(haystack, (char)*needle_bytes);
+
+  const uint8_t *last = haystack_bytes + haystack_len - needle_len;
+  for (const uint8_t *cur = haystack_bytes; cur != last; ++cur) {
+    if (0 == memcmp(cur, needle_bytes, needle_len)) {
+      return (int)(cur - haystack_bytes);
+    }
+  }
+  return -1;
+}
+
+grpc_slice grpc_slice_dup(grpc_slice a) {
+  grpc_slice copy = grpc_slice_malloc(GRPC_SLICE_LENGTH(a));
+  memcpy(GRPC_SLICE_START_PTR(copy), GRPC_SLICE_START_PTR(a),
+         GRPC_SLICE_LENGTH(a));
+  return copy;
+}