Merge branch 'master' of https://github.com/grpc/grpc into channelz-subchannels

BUILD

@@ -1433,7 +1433,10 @@ grpc_cc_library(
         "src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc",
         "src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver.cc",
         "src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_posix.cc",
+        "src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_windows.cc",
         "src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.cc",
+        "src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_posix.cc",
+        "src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_windows.cc",
         "src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_fallback.cc",
     ],
     hdrs = [

CMakeLists.txt

@@ -298,6 +298,7 @@ add_dependencies(buildtests_c grpc_completion_queue_test)
 add_dependencies(buildtests_c grpc_completion_queue_threading_test)
 add_dependencies(buildtests_c grpc_credentials_test)
 add_dependencies(buildtests_c grpc_fetch_oauth2)
+add_dependencies(buildtests_c grpc_ipv6_loopback_available_test)
 if(_gRPC_PLATFORM_LINUX OR _gRPC_PLATFORM_MAC OR _gRPC_PLATFORM_POSIX)
 add_dependencies(buildtests_c grpc_json_token_test)
 endif()
@@ -671,12 +672,8 @@ endif()
 if(_gRPC_PLATFORM_LINUX OR _gRPC_PLATFORM_MAC OR _gRPC_PLATFORM_POSIX)
 add_dependencies(buildtests_cxx resolver_component_tests_runner_invoker)
 endif()
-if(_gRPC_PLATFORM_LINUX OR _gRPC_PLATFORM_MAC OR _gRPC_PLATFORM_POSIX)
 add_dependencies(buildtests_cxx address_sorting_test_unsecure)
-endif()
-if(_gRPC_PLATFORM_LINUX OR _gRPC_PLATFORM_MAC OR _gRPC_PLATFORM_POSIX)
 add_dependencies(buildtests_cxx address_sorting_test)
-endif()
 if(_gRPC_PLATFORM_LINUX OR _gRPC_PLATFORM_MAC OR _gRPC_PLATFORM_POSIX)
 add_dependencies(buildtests_cxx cancel_ares_query_test)
 endif()
@@ -1236,8 +1233,11 @@ add_library(grpc
   src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc
   src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver.cc
   src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_posix.cc
+  src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_windows.cc
   src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.cc
   src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_fallback.cc
+  src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_posix.cc
+  src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_windows.cc
   src/core/ext/filters/client_channel/resolver/dns/native/dns_resolver.cc
   src/core/ext/filters/client_channel/resolver/sockaddr/sockaddr_resolver.cc
   src/cpp/ext/filters/census/grpc_context.cc
@@ -2538,8 +2538,11 @@ add_library(grpc_unsecure
   src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc
   src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver.cc
   src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_posix.cc
+  src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_windows.cc
   src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.cc
   src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_fallback.cc
+  src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_posix.cc
+  src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_windows.cc
   src/core/ext/filters/client_channel/resolver/dns/native/dns_resolver.cc
   src/core/ext/filters/client_channel/resolver/sockaddr/sockaddr_resolver.cc
   src/core/ext/filters/client_channel/resolver/fake/fake_resolver.cc
@@ -7323,6 +7326,35 @@ target_link_libraries(grpc_fetch_oauth2
   gpr
 )
 
+endif (gRPC_BUILD_TESTS)
+if (gRPC_BUILD_TESTS)
+
+add_executable(grpc_ipv6_loopback_available_test
+  test/core/iomgr/grpc_ipv6_loopback_available_test.cc
+)
+
+
+target_include_directories(grpc_ipv6_loopback_available_test
+  PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}
+  PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/include
+  PRIVATE ${_gRPC_SSL_INCLUDE_DIR}
+  PRIVATE ${_gRPC_PROTOBUF_INCLUDE_DIR}
+  PRIVATE ${_gRPC_ZLIB_INCLUDE_DIR}
+  PRIVATE ${_gRPC_BENCHMARK_INCLUDE_DIR}
+  PRIVATE ${_gRPC_CARES_INCLUDE_DIR}
+  PRIVATE ${_gRPC_GFLAGS_INCLUDE_DIR}
+  PRIVATE ${_gRPC_ADDRESS_SORTING_INCLUDE_DIR}
+  PRIVATE ${_gRPC_NANOPB_INCLUDE_DIR}
+)
+
+target_link_libraries(grpc_ipv6_loopback_available_test
+  ${_gRPC_ALLTARGETS_LIBRARIES}
+  grpc_test_util
+  grpc
+  gpr_test_util
+  gpr
+)
+
 endif (gRPC_BUILD_TESTS)
 if (gRPC_BUILD_TESTS)
 if(_gRPC_PLATFORM_LINUX OR _gRPC_PLATFORM_MAC OR _gRPC_PLATFORM_POSIX)
@@ -16351,7 +16383,6 @@ target_link_libraries(resolver_component_tests_runner_invoker
 endif()
 endif (gRPC_BUILD_TESTS)
 if (gRPC_BUILD_TESTS)
-if(_gRPC_PLATFORM_LINUX OR _gRPC_PLATFORM_MAC OR _gRPC_PLATFORM_POSIX)
 
 add_executable(address_sorting_test_unsecure
   test/cpp/naming/address_sorting_test.cc
@@ -16391,10 +16422,8 @@ target_link_libraries(address_sorting_test_unsecure
   ${_gRPC_GFLAGS_LIBRARIES}
 )
 
-endif()
 endif (gRPC_BUILD_TESTS)
 if (gRPC_BUILD_TESTS)
-if(_gRPC_PLATFORM_LINUX OR _gRPC_PLATFORM_MAC OR _gRPC_PLATFORM_POSIX)
 
 add_executable(address_sorting_test
   test/cpp/naming/address_sorting_test.cc
@@ -16434,7 +16463,6 @@ target_link_libraries(address_sorting_test
   ${_gRPC_GFLAGS_LIBRARIES}
 )
 
-endif()
 endif (gRPC_BUILD_TESTS)
 if (gRPC_BUILD_TESTS)
 if(_gRPC_PLATFORM_LINUX OR _gRPC_PLATFORM_MAC OR _gRPC_PLATFORM_POSIX)

Makefile

@@ -1022,6 +1022,7 @@ grpc_completion_queue_threading_test: $(BINDIR)/$(CONFIG)/grpc_completion_queue_
 grpc_create_jwt: $(BINDIR)/$(CONFIG)/grpc_create_jwt
 grpc_credentials_test: $(BINDIR)/$(CONFIG)/grpc_credentials_test
 grpc_fetch_oauth2: $(BINDIR)/$(CONFIG)/grpc_fetch_oauth2
+grpc_ipv6_loopback_available_test: $(BINDIR)/$(CONFIG)/grpc_ipv6_loopback_available_test
 grpc_json_token_test: $(BINDIR)/$(CONFIG)/grpc_json_token_test
 grpc_jwt_verifier_test: $(BINDIR)/$(CONFIG)/grpc_jwt_verifier_test
 grpc_print_google_default_creds_token: $(BINDIR)/$(CONFIG)/grpc_print_google_default_creds_token
@@ -1472,6 +1473,7 @@ buildtests_c: privatelibs_c \
   $(BINDIR)/$(CONFIG)/grpc_completion_queue_threading_test \
   $(BINDIR)/$(CONFIG)/grpc_credentials_test \
   $(BINDIR)/$(CONFIG)/grpc_fetch_oauth2 \
+  $(BINDIR)/$(CONFIG)/grpc_ipv6_loopback_available_test \
   $(BINDIR)/$(CONFIG)/grpc_json_token_test \
   $(BINDIR)/$(CONFIG)/grpc_jwt_verifier_test \
   $(BINDIR)/$(CONFIG)/grpc_security_connector_test \
@@ -2028,6 +2030,8 @@ test_c: buildtests_c
 	$(Q) $(BINDIR)/$(CONFIG)/grpc_completion_queue_threading_test || ( echo test grpc_completion_queue_threading_test failed ; exit 1 )
 	$(E) "[RUN]     Testing grpc_credentials_test"
 	$(Q) $(BINDIR)/$(CONFIG)/grpc_credentials_test || ( echo test grpc_credentials_test failed ; exit 1 )
+	$(E) "[RUN]     Testing grpc_ipv6_loopback_available_test"
+	$(Q) $(BINDIR)/$(CONFIG)/grpc_ipv6_loopback_available_test || ( echo test grpc_ipv6_loopback_available_test failed ; exit 1 )
 	$(E) "[RUN]     Testing grpc_json_token_test"
 	$(Q) $(BINDIR)/$(CONFIG)/grpc_json_token_test || ( echo test grpc_json_token_test failed ; exit 1 )
 	$(E) "[RUN]     Testing grpc_jwt_verifier_test"
@@ -3704,8 +3708,11 @@ LIBGRPC_SRC = \
     src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc \
     src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver.cc \
     src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_posix.cc \
+    src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_windows.cc \
     src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.cc \
     src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_fallback.cc \
+    src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_posix.cc \
+    src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_windows.cc \
     src/core/ext/filters/client_channel/resolver/dns/native/dns_resolver.cc \
     src/core/ext/filters/client_channel/resolver/sockaddr/sockaddr_resolver.cc \
     src/cpp/ext/filters/census/grpc_context.cc \
@@ -4972,8 +4979,11 @@ LIBGRPC_UNSECURE_SRC = \
     src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc \
     src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver.cc \
     src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_posix.cc \
+    src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_windows.cc \
     src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.cc \
     src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_fallback.cc \
+    src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_posix.cc \
+    src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_windows.cc \
     src/core/ext/filters/client_channel/resolver/dns/native/dns_resolver.cc \
     src/core/ext/filters/client_channel/resolver/sockaddr/sockaddr_resolver.cc \
     src/core/ext/filters/client_channel/resolver/fake/fake_resolver.cc \
@@ -12365,6 +12375,38 @@ endif
 endif
 
 
+GRPC_IPV6_LOOPBACK_AVAILABLE_TEST_SRC = \
+    test/core/iomgr/grpc_ipv6_loopback_available_test.cc \
+
+GRPC_IPV6_LOOPBACK_AVAILABLE_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(GRPC_IPV6_LOOPBACK_AVAILABLE_TEST_SRC))))
+ifeq ($(NO_SECURE),true)
+
+# You can't build secure targets if you don't have OpenSSL.
+
+$(BINDIR)/$(CONFIG)/grpc_ipv6_loopback_available_test: openssl_dep_error
+
+else
+
+
+
+$(BINDIR)/$(CONFIG)/grpc_ipv6_loopback_available_test: $(GRPC_IPV6_LOOPBACK_AVAILABLE_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) $(GRPC_IPV6_LOOPBACK_AVAILABLE_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)/grpc_ipv6_loopback_available_test
+
+endif
+
+$(OBJDIR)/$(CONFIG)/test/core/iomgr/grpc_ipv6_loopback_available_test.o:  $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+
+deps_grpc_ipv6_loopback_available_test: $(GRPC_IPV6_LOOPBACK_AVAILABLE_TEST_OBJS:.o=.dep)
+
+ifneq ($(NO_SECURE),true)
+ifneq ($(NO_DEPS),true)
+-include $(GRPC_IPV6_LOOPBACK_AVAILABLE_TEST_OBJS:.o=.dep)
+endif
+endif
+
+
 GRPC_JSON_TOKEN_TEST_SRC = \
     test/core/security/json_token_test.cc \
 

WORKSPACE

@@ -1,5 +1,44 @@
-workspace(name = "com_github_grpc_grpc")
+workspace(name="com_github_grpc_grpc")
 
 load("//bazel:grpc_deps.bzl", "grpc_deps", "grpc_test_only_deps")
 grpc_deps()
 grpc_test_only_deps()
+
+new_http_archive(
+    name="cython",
+    sha256="d68138a2381afbdd0876c3cb2a22389043fa01c4badede1228ee073032b07a27",
+    urls=[
+        "https://github.com/cython/cython/archive/c2b80d87658a8525ce091cbe146cb7eaa29fed5c.tar.gz",
+    ],
+    strip_prefix="cython-c2b80d87658a8525ce091cbe146cb7eaa29fed5c",
+    build_file="//third_party:cython.BUILD",
+)
+
+load("//third_party/py:python_configure.bzl", "python_configure")
+python_configure(name="local_config_python")
+
+git_repository(
+    name="io_bazel_rules_python",
+    remote="https://github.com/bazelbuild/rules_python.git",
+    commit="8b5d0683a7d878b28fffe464779c8a53659fc645",
+)
+
+load("@io_bazel_rules_python//python:pip.bzl", "pip_repositories", "pip_import")
+
+pip_repositories()
+pip_import(
+    name="grpc_python_dependencies",
+    requirements="//:requirements.bazel.txt",
+)
+
+load("@grpc_python_dependencies//:requirements.bzl", "pip_install")
+pip_install()
+
+git_repository(
+    name="org_pubref_rules_protobuf",
+    remote="https://github.com/pubref/rules_protobuf",
+    tag="v0.8.2",
+)
+
+load("@org_pubref_rules_protobuf//python:rules.bzl", "py_proto_repositories")
+py_proto_repositories()

bazel/cython_library.bzl

@@ -0,0 +1,74 @@
+"""Custom rules for gRPC Python"""
+
+
+# Adapted with modifications from
+# tensorflow/tensorflow/core/platform/default/build_config.bzl
+# Native Bazel rules don't exist yet to compile Cython code, but rules have
+# been written at cython/cython and tensorflow/tensorflow. We branch from
+# Tensorflow's version as it is more actively maintained and works for gRPC
+# Python's needs.
+def pyx_library(name, deps=[], py_deps=[], srcs=[], **kwargs):
+    """Compiles a group of .pyx / .pxd / .py files.
+
+    First runs Cython to create .cpp files for each input .pyx or .py + .pxd
+    pair. Then builds a shared object for each, passing "deps" to each cc_binary
+    rule (includes Python headers by default). Finally, creates a py_library rule
+    with the shared objects and any pure Python "srcs", with py_deps as its
+    dependencies; the shared objects can be imported like normal Python files.
+
+    Args:
+        name: Name for the rule.
+        deps: C/C++ dependencies of the Cython (e.g. Numpy headers).
+        py_deps: Pure Python dependencies of the final library.
+        srcs: .py, .pyx, or .pxd files to either compile or pass through.
+        **kwargs: Extra keyword arguments passed to the py_library.
+    """
+    # First filter out files that should be run compiled vs. passed through.
+    py_srcs = []
+    pyx_srcs = []
+    pxd_srcs = []
+    for src in srcs:
+        if src.endswith(".pyx") or (src.endswith(".py") and
+                                    src[:-3] + ".pxd" in srcs):
+            pyx_srcs.append(src)
+        elif src.endswith(".py"):
+            py_srcs.append(src)
+        else:
+            pxd_srcs.append(src)
+        if src.endswith("__init__.py"):
+            pxd_srcs.append(src)
+
+    # Invoke cython to produce the shared object libraries.
+    for filename in pyx_srcs:
+        native.genrule(
+            name=filename + "_cython_translation",
+            srcs=[filename],
+            outs=[filename.split(".")[0] + ".cpp"],
+            # Optionally use PYTHON_BIN_PATH on Linux platforms so that python 3
+            # works. Windows has issues with cython_binary so skip PYTHON_BIN_PATH.
+            cmd=
+            "PYTHONHASHSEED=0 $(location @cython//:cython_binary) --cplus $(SRCS) --output-file $(OUTS)",
+            tools=["@cython//:cython_binary"] + pxd_srcs,
+        )
+
+    shared_objects = []
+    for src in pyx_srcs:
+        stem = src.split(".")[0]
+        shared_object_name = stem + ".so"
+        native.cc_binary(
+            name=shared_object_name,
+            srcs=[stem + ".cpp"],
+            deps=deps + ["@local_config_python//:python_headers"],
+            linkshared=1,
+        )
+        shared_objects.append(shared_object_name)
+
+    # Now create a py_library with these shared objects as data.
+    native.py_library(
+        name=name,
+        srcs=py_srcs,
+        deps=py_deps,
+        srcs_version="PY2AND3",
+        data=shared_objects,
+        **kwargs)
+

build.yaml

@@ -740,8 +740,11 @@ filegroups:
   - src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc
   - src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver.cc
   - src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_posix.cc
+  - src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_windows.cc
   - src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.cc
   - src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_fallback.cc
+  - src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_posix.cc
+  - src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_windows.cc
   plugin: grpc_resolver_dns_ares
   uses:
   - grpc_base
@@ -2730,6 +2733,18 @@ targets:
   - grpc
   - gpr_test_util
   - gpr
+- name: grpc_ipv6_loopback_available_test
+  build: test
+  language: c
+  src:
+  - test/core/iomgr/grpc_ipv6_loopback_available_test.cc
+  deps:
+  - grpc_test_util
+  - grpc
+  - gpr_test_util
+  - gpr
+  exclude_iomgrs:
+  - uv
 - name: grpc_json_token_test
   build: test
   language: c

composer.json

@@ -9,7 +9,7 @@
     "php": ">=5.5.0"
   },
   "require-dev": {
-    "google/auth": "v0.9"
+    "google/auth": "^v1.3.0"
   },
   "suggest": {
     "ext-protobuf": "For better performance, install the protobuf C extension.",

config.m4

@@ -380,8 +380,11 @@ if test "$PHP_GRPC" != "no"; then
     src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc \
     src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver.cc \
     src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_posix.cc \
+    src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_windows.cc \
     src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.cc \
     src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_fallback.cc \
+    src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_posix.cc \
+    src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_windows.cc \
     src/core/ext/filters/client_channel/resolver/dns/native/dns_resolver.cc \
     src/core/ext/filters/client_channel/resolver/sockaddr/sockaddr_resolver.cc \
     src/cpp/ext/filters/census/grpc_context.cc \

config.w32

@@ -355,8 +355,11 @@ if (PHP_GRPC != "no") {
     "src\\core\\ext\\filters\\client_channel\\resolver\\dns\\c_ares\\dns_resolver_ares.cc " +
     "src\\core\\ext\\filters\\client_channel\\resolver\\dns\\c_ares\\grpc_ares_ev_driver.cc " +
     "src\\core\\ext\\filters\\client_channel\\resolver\\dns\\c_ares\\grpc_ares_ev_driver_posix.cc " +
+    "src\\core\\ext\\filters\\client_channel\\resolver\\dns\\c_ares\\grpc_ares_ev_driver_windows.cc " +
     "src\\core\\ext\\filters\\client_channel\\resolver\\dns\\c_ares\\grpc_ares_wrapper.cc " +
     "src\\core\\ext\\filters\\client_channel\\resolver\\dns\\c_ares\\grpc_ares_wrapper_fallback.cc " +
+    "src\\core\\ext\\filters\\client_channel\\resolver\\dns\\c_ares\\grpc_ares_wrapper_posix.cc " +
+    "src\\core\\ext\\filters\\client_channel\\resolver\\dns\\c_ares\\grpc_ares_wrapper_windows.cc " +
     "src\\core\\ext\\filters\\client_channel\\resolver\\dns\\native\\dns_resolver.cc " +
     "src\\core\\ext\\filters\\client_channel\\resolver\\sockaddr\\sockaddr_resolver.cc " +
     "src\\cpp\\ext\\filters\\census\\grpc_context.cc " +

doc/server-reflection.md

@@ -181,3 +181,16 @@ will need to index those FileDescriptorProtos by file and symbol and imports.
 One issue is that some grpc implementations are very loosely coupled with
 protobufs; in such implementations it probably makes sense to split apart these
 reflection APIs so as not to take an additional proto dependency.
+
+## Known Implementations
+
+Enabling server reflection differs language-to-language. Here are links to docs relevant to
+each language:
+
+- [Java](https://github.com/grpc/grpc-java/blob/master/documentation/server-reflection-tutorial.md#enable-server-reflection)
+- [Go](https://github.com/grpc/grpc-go/blob/master/Documentation/server-reflection-tutorial.md#enable-server-reflection)
+- [C++](https://grpc.io/grpc/cpp/md_doc_server_reflection_tutorial.html)
+- [C#](https://github.com/grpc/grpc/blob/master/doc/csharp/server_reflection.md)
+- Python: (tutorial not yet written)
+- Ruby: not yet implemented [#2567](https://github.com/grpc/grpc/issues/2567)
+- Node: not yet implemented [#2568](https://github.com/grpc/grpc/issues/2568)

examples/csharp/HelloworldXamarin/.gitignore

@@ -0,0 +1,41 @@
+# Autosave files
+*~
+
+# build
+[Oo]bj/
+[Bb]in/
+packages/
+TestResults/
+
+# globs
+Makefile.in
+*.DS_Store
+*.sln.cache
+*.suo
+*.cache
+*.pidb
+*.userprefs
+*.usertasks
+config.log
+config.make
+config.status
+aclocal.m4
+install-sh
+autom4te.cache/
+*.user
+*.tar.gz
+tarballs/
+test-results/
+Thumbs.db
+.vs/
+
+# Mac bundle stuff
+*.dmg
+*.app
+
+# resharper
+*_Resharper.*
+*.Resharper
+
+# dotCover
+*.dotCover

examples/csharp/HelloworldXamarin/Droid/Assets/AboutAssets.txt

@@ -0,0 +1,19 @@
+Any raw assets you want to be deployed with your application can be placed in
+this directory (and child directories) and given a Build Action of "AndroidAsset".
+
+These files will be deployed with your package and will be accessible using Android's
+AssetManager, like this:
+
+public class ReadAsset : Activity
+{
+	protected override void OnCreate (Bundle bundle)
+	{
+		base.OnCreate (bundle);
+
+		InputStream input = Assets.Open ("my_asset.txt");
+	}
+}
+
+Additionally, some Android functions will automatically load asset files:
+
+Typeface tf = Typeface.CreateFromAsset (Context.Assets, "fonts/samplefont.ttf");

examples/csharp/HelloworldXamarin/Droid/HelloworldXamarin.Droid.csproj

@@ -0,0 +1,83 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project DefaultTargets="Build" ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup>
+    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
+    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
+    <ProjectGuid>{B9B0D41C-1C07-4590-A919-5865E741B2EA}</ProjectGuid>
+    <ProjectTypeGuids>{EFBA0AD7-5A72-4C68-AF49-83D382785DCF};{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}</ProjectTypeGuids>
+    <OutputType>Library</OutputType>
+    <RootNamespace>HelloworldXamarin.Droid</RootNamespace>
+    <AssemblyName>HelloworldXamarin.Droid</AssemblyName>
+    <TargetFrameworkVersion>v8.1</TargetFrameworkVersion>
+    <AndroidApplication>True</AndroidApplication>
+    <AndroidResgenFile>Resources\Resource.designer.cs</AndroidResgenFile>
+    <AndroidResgenClass>Resource</AndroidResgenClass>
+    <AndroidManifest>Properties\AndroidManifest.xml</AndroidManifest>
+    <MonoAndroidResourcePrefix>Resources</MonoAndroidResourcePrefix>
+    <MonoAndroidAssetsPrefix>Assets</MonoAndroidAssetsPrefix>
+    <AndroidUseLatestPlatformSdk>true</AndroidUseLatestPlatformSdk>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
+    <DebugSymbols>true</DebugSymbols>
+    <DebugType>full</DebugType>
+    <Optimize>false</Optimize>
+    <OutputPath>bin\Debug</OutputPath>
+    <DefineConstants>DEBUG;</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+    <AndroidLinkMode>None</AndroidLinkMode>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
+    <DebugSymbols>true</DebugSymbols>
+    <DebugType>pdbonly</DebugType>
+    <Optimize>true</Optimize>
+    <OutputPath>bin\Release</OutputPath>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+    <AndroidManagedSymbols>true</AndroidManagedSymbols>
+    <AndroidUseSharedRuntime>false</AndroidUseSharedRuntime>
+  </PropertyGroup>
+  <ItemGroup>
+    <Reference Include="System" />
+    <Reference Include="System.Xml" />
+    <Reference Include="System.Core" />
+    <Reference Include="Mono.Android" />
+    <Reference Include="System.IO.Compression" />
+    <Reference Include="System.Net.Http" />
+    <Reference Include="System.Runtime.Loader">
+      <HintPath>..\packages\System.Runtime.Loader.4.0.0\lib\netstandard1.5\System.Runtime.Loader.dll</HintPath>
+    </Reference>
+    <Reference Include="System.Interactive.Async">
+      <HintPath>..\packages\System.Interactive.Async.3.1.1\lib\netstandard1.3\System.Interactive.Async.dll</HintPath>
+    </Reference>
+    <Reference Include="Grpc.Core">
+      <HintPath>..\packages\Grpc.Core.1.15.0-dev\lib\netstandard1.5\Grpc.Core.dll</HintPath>
+    </Reference>
+    <Reference Include="Google.Protobuf">
+      <HintPath>..\packages\Google.Protobuf.3.6.0\lib\netstandard1.0\Google.Protobuf.dll</HintPath>
+    </Reference>
+  </ItemGroup>
+  <ItemGroup>
+    <Compile Include="MainActivity.cs" />
+    <Compile Include="Resources\Resource.designer.cs" />
+    <Compile Include="Properties\AssemblyInfo.cs" />
+  </ItemGroup>
+  <ItemGroup>
+    <None Include="Resources\AboutResources.txt" />
+    <None Include="Properties\AndroidManifest.xml" />
+    <None Include="Assets\AboutAssets.txt" />
+    <None Include="packages.config" />
+  </ItemGroup>
+  <ItemGroup>
+    <AndroidResource Include="Resources\layout\Main.axml" />
+    <AndroidResource Include="Resources\values\Strings.xml" />
+    <AndroidResource Include="Resources\mipmap-hdpi\Icon.png" />
+    <AndroidResource Include="Resources\mipmap-mdpi\Icon.png" />
+    <AndroidResource Include="Resources\mipmap-xhdpi\Icon.png" />
+    <AndroidResource Include="Resources\mipmap-xxhdpi\Icon.png" />
+    <AndroidResource Include="Resources\mipmap-xxxhdpi\Icon.png" />
+  </ItemGroup>
+  <Import Project="..\HelloworldXamarin\HelloworldXamarin.projitems" Label="Shared" Condition="Exists('..\HelloworldXamarin\HelloworldXamarin.projitems')" />
+  <Import Project="$(MSBuildExtensionsPath)\Xamarin\Android\Xamarin.Android.CSharp.targets" />
+  <Import Project="..\packages\Grpc.Core.1.15.0-dev\build\MonoAndroid\Grpc.Core.targets" Condition="Exists('..\packages\Grpc.Core.1.15.0-dev\build\MonoAndroid\Grpc.Core.targets')" />
+</Project>

examples/csharp/HelloworldXamarin/Droid/MainActivity.cs

@@ -0,0 +1,84 @@
+#region Copyright notice and license
+
+// Copyright 2018 The gRPC Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#endregion
+
+using Android.App;
+using Android.Widget;
+using Android.OS;
+using System.Threading.Tasks;
+using Grpc.Core;
+using Helloworld;
+
+namespace HelloworldXamarin.Droid
+{
+    [Activity(Label = "HelloworldXamarin", MainLauncher = true, Icon = "@mipmap/icon")]
+    public class MainActivity : Activity
+    {
+        const int Port = 50051;
+        int count = 1;
+
+        protected override void OnCreate(Bundle savedInstanceState)
+        {
+            base.OnCreate(savedInstanceState);
+
+            // Set our view from the "main" layout resource
+            SetContentView(Resource.Layout.Main);
+
+            // Get our button from the layout resource,
+            // and attach an event to it
+            Button button = FindViewById<Button>(Resource.Id.myButton);
+
+            button.Click += delegate { SayHello(button); };
+        }
+
+        private void SayHello(Button button)
+        {
+            Server server = new Server
+            {
+              Services = { Greeter.BindService(new GreeterImpl()) },
+              Ports = { new ServerPort("localhost", Port, ServerCredentials.Insecure) }
+            };
+            server.Start();
+
+            // use loopback on host machine: https://developer.android.com/studio/run/emulator-networking
+            //10.0.2.2:50051
+            Channel channel = new Channel("localhost:50051", ChannelCredentials.Insecure);
+
+            var client = new Greeter.GreeterClient(channel);
+            string user = "Xamarin " + count;
+
+            var reply = client.SayHello(new HelloRequest { Name = user });
+
+            button.Text = "Greeting: " + reply.Message;
+
+            channel.ShutdownAsync().Wait();
+            server.ShutdownAsync().Wait();
+
+            count++;
+        }
+
+        class GreeterImpl : Greeter.GreeterBase
+        {
+            // Server side handler of the SayHello RPC
+            public override Task<HelloReply> SayHello(HelloRequest request, ServerCallContext context)
+            {
+              return Task.FromResult(new HelloReply { Message = "Hello " + request.Name });
+            }
+        }
+    }
+}
+

examples/csharp/HelloworldXamarin/Droid/Properties/AndroidManifest.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android" android:versionCode="1" android:versionName="1.0" package="io.grpc.examples.HelloworldXamarin">
+    <uses-sdk android:minSdkVersion="15" />
+    <application android:label="HelloworldXamarin">
+    </application>
+</manifest>

examples/csharp/HelloworldXamarin/Droid/Properties/AssemblyInfo.cs

@@ -0,0 +1,45 @@
+#region Copyright notice and license
+
+// Copyright 2018 The gRPC Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#endregion
+
+using System.Reflection;
+using System.Runtime.CompilerServices;
+using Android.App;
+
+// Information about this assembly is defined by the following attributes. 
+// Change them to the values specific to your project.
+
+[assembly: AssemblyTitle("HelloworldXamarin.Droid")]
+[assembly: AssemblyDescription("")]
+[assembly: AssemblyConfiguration("")]
+[assembly: AssemblyCompany("")]
+[assembly: AssemblyProduct("")]
+[assembly: AssemblyCopyright("${AuthorCopyright}")]
+[assembly: AssemblyTrademark("")]
+[assembly: AssemblyCulture("")]
+
+// The assembly version has the format "{Major}.{Minor}.{Build}.{Revision}".
+// The form "{Major}.{Minor}.*" will automatically update the build and revision,
+// and "{Major}.{Minor}.{Build}.*" will update just the revision.
+
+[assembly: AssemblyVersion("1.0.0")]
+
+// The following attributes are used to specify the signing key for the assembly, 
+// if desired. See the Mono documentation for more information about signing.
+
+//[assembly: AssemblyDelaySign(false)]
+//[assembly: AssemblyKeyFile("")]

examples/csharp/HelloworldXamarin/Droid/Resources/AboutResources.txt

@@ -0,0 +1,44 @@
+Images, layout descriptions, binary blobs and string dictionaries can be included 
+in your application as resource files.  Various Android APIs are designed to 
+operate on the resource IDs instead of dealing with images, strings or binary blobs 
+directly.
+
+For example, a sample Android app that contains a user interface layout (main.axml),
+an internationalization string table (strings.xml) and some icons (drawable-XXX/icon.png) 
+would keep its resources in the "Resources" directory of the application:
+
+Resources/
+    drawable/
+        icon.png
+
+    layout/
+        main.axml
+
+    values/
+        strings.xml
+
+In order to get the build system to recognize Android resources, set the build action to
+"AndroidResource".  The native Android APIs do not operate directly with filenames, but 
+instead operate on resource IDs.  When you compile an Android application that uses resources, 
+the build system will package the resources for distribution and generate a class called "R" 
+(this is an Android convention) that contains the tokens for each one of the resources 
+included. For example, for the above Resources layout, this is what the R class would expose:
+
+public class R {
+    public class drawable {
+        public const int icon = 0x123;
+    }
+
+    public class layout {
+        public const int main = 0x456;
+    }
+
+    public class strings {
+        public const int first_string = 0xabc;
+        public const int second_string = 0xbcd;
+    }
+}
+
+You would then use R.drawable.icon to reference the drawable/icon.png file, or R.layout.main 
+to reference the layout/main.axml file, or R.strings.first_string to reference the first 
+string in the dictionary file values/strings.xml.

examples/csharp/HelloworldXamarin/Droid/Resources/Resource.designer.cs

@@ -0,0 +1,112 @@
+#pragma warning disable 1591
+//------------------------------------------------------------------------------
+// <auto-generated>
+//     This code was generated by a tool.
+//     Runtime Version:4.0.30319.42000
+//
+//     Changes to this file may cause incorrect behavior and will be lost if
+//     the code is regenerated.
+// </auto-generated>
+//------------------------------------------------------------------------------
+
+[assembly: global::Android.Runtime.ResourceDesignerAttribute("HelloworldXamarin.Droid.Resource", IsApplication=true)]
+
+namespace HelloworldXamarin.Droid
+{
+	
+	
+	[System.CodeDom.Compiler.GeneratedCodeAttribute("Xamarin.Android.Build.Tasks", "1.0.0.0")]
+	public partial class Resource
+	{
+		
+		static Resource()
+		{
+			global::Android.Runtime.ResourceIdManager.UpdateIdValues();
+		}
+		
+		public static void UpdateIdValues()
+		{
+		}
+		
+		public partial class Attribute
+		{
+			
+			static Attribute()
+			{
+				global::Android.Runtime.ResourceIdManager.UpdateIdValues();
+			}
+			
+			private Attribute()
+			{
+			}
+		}
+		
+		public partial class Id
+		{
+			
+			// aapt resource value: 0x7f050000
+			public const int myButton = 2131034112;
+			
+			static Id()
+			{
+				global::Android.Runtime.ResourceIdManager.UpdateIdValues();
+			}
+			
+			private Id()
+			{
+			}
+		}
+		
+		public partial class Layout
+		{
+			
+			// aapt resource value: 0x7f030000
+			public const int Main = 2130903040;
+			
+			static Layout()
+			{
+				global::Android.Runtime.ResourceIdManager.UpdateIdValues();
+			}
+			
+			private Layout()
+			{
+			}
+		}
+		
+		public partial class Mipmap
+		{
+			
+			// aapt resource value: 0x7f020000
+			public const int Icon = 2130837504;
+			
+			static Mipmap()
+			{
+				global::Android.Runtime.ResourceIdManager.UpdateIdValues();
+			}
+			
+			private Mipmap()
+			{
+			}
+		}
+		
+		public partial class String
+		{
+			
+			// aapt resource value: 0x7f040001
+			public const int app_name = 2130968577;
+			
+			// aapt resource value: 0x7f040000
+			public const int hello = 2130968576;
+			
+			static String()
+			{
+				global::Android.Runtime.ResourceIdManager.UpdateIdValues();
+			}
+			
+			private String()
+			{
+			}
+		}
+	}
+}
+#pragma warning restore 1591

examples/csharp/HelloworldXamarin/Droid/Resources/layout/Main.axml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="match_parent" android:layout_height="match_parent">
+    <Button android:id="@+id/myButton" android:layout_width="match_parent" android:layout_height="wrap_content" android:text="@string/hello" />
+</LinearLayout>

examples/csharp/HelloworldXamarin/Droid/Resources/values/Strings.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <string name="hello">Hello World, Click Me!</string>
+    <string name="app_name">HelloworldXamarin.Droid</string>
+</resources>

examples/csharp/HelloworldXamarin/Droid/packages.config

@@ -0,0 +1,54 @@
+<?xml version="1.0" encoding="utf-8"?>
+<packages>
+  <package id="Google.Protobuf" version="3.6.0" targetFramework="monoandroid81" />
+  <package id="Grpc.Core" version="1.15.0-dev" targetFramework="monoandroid81" />
+  <package id="Microsoft.NETCore.Platforms" version="1.1.0" targetFramework="monoandroid81" />
+  <package id="Microsoft.Win32.Primitives" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="NETStandard.Library" version="1.6.1" targetFramework="monoandroid81" />
+  <package id="System.AppContext" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.Collections" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.Collections.Concurrent" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.Console" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.Diagnostics.Debug" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.Diagnostics.Tools" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.Diagnostics.Tracing" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.Globalization" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.Globalization.Calendars" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.Interactive.Async" version="3.1.1" targetFramework="monoandroid81" />
+  <package id="System.IO" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.IO.Compression" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.IO.Compression.ZipFile" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.IO.FileSystem" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.IO.FileSystem.Primitives" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.Linq" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.Linq.Expressions" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.Net.Http" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.Net.Primitives" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.Net.Sockets" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.ObjectModel" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.Reflection" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.Reflection.Extensions" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.Reflection.Primitives" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.Resources.ResourceManager" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.Runtime" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.Runtime.Extensions" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.Runtime.Handles" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.Runtime.InteropServices" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.Runtime.InteropServices.RuntimeInformation" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.Runtime.Loader" version="4.0.0" targetFramework="monoandroid81" />
+  <package id="System.Runtime.Numerics" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.Security.Cryptography.Algorithms" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.Security.Cryptography.Encoding" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.Security.Cryptography.Primitives" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.Security.Cryptography.X509Certificates" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.Text.Encoding" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.Text.Encoding.Extensions" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.Text.RegularExpressions" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.Threading" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.Threading.Tasks" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.Threading.Thread" version="4.0.0" targetFramework="monoandroid81" />
+  <package id="System.Threading.ThreadPool" version="4.0.10" targetFramework="monoandroid81" />
+  <package id="System.Threading.Timer" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.Xml.ReaderWriter" version="4.3.0" targetFramework="monoandroid81" />
+  <package id="System.Xml.XDocument" version="4.3.0" targetFramework="monoandroid81" />
+</packages>

examples/csharp/HelloworldXamarin/HelloworldXamarin.sln

@@ -0,0 +1,45 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio 2012
+Project("{D954291E-2A0B-460D-934E-DC6B0785DB48}") = "HelloworldXamarin", "HelloworldXamarin\HelloworldXamarin.shproj", "{42FFF3D8-934F-4475-8E68-08DA340BF6E8}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "HelloworldXamarin.Droid", "Droid\HelloworldXamarin.Droid.csproj", "{B9B0D41C-1C07-4590-A919-5865E741B2EA}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "HelloworldXamarin.iOS", "iOS\HelloworldXamarin.iOS.csproj", "{62336DF0-60D8-478F-8140-B3CB089B417E}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+		Debug|iPhoneSimulator = Debug|iPhoneSimulator
+		Release|iPhone = Release|iPhone
+		Release|iPhoneSimulator = Release|iPhoneSimulator
+		Debug|iPhone = Debug|iPhone
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{B9B0D41C-1C07-4590-A919-5865E741B2EA}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{B9B0D41C-1C07-4590-A919-5865E741B2EA}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{B9B0D41C-1C07-4590-A919-5865E741B2EA}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{B9B0D41C-1C07-4590-A919-5865E741B2EA}.Release|Any CPU.Build.0 = Release|Any CPU
+		{B9B0D41C-1C07-4590-A919-5865E741B2EA}.Debug|iPhoneSimulator.ActiveCfg = Debug|Any CPU
+		{B9B0D41C-1C07-4590-A919-5865E741B2EA}.Debug|iPhoneSimulator.Build.0 = Debug|Any CPU
+		{B9B0D41C-1C07-4590-A919-5865E741B2EA}.Release|iPhone.ActiveCfg = Release|Any CPU
+		{B9B0D41C-1C07-4590-A919-5865E741B2EA}.Release|iPhone.Build.0 = Release|Any CPU
+		{B9B0D41C-1C07-4590-A919-5865E741B2EA}.Release|iPhoneSimulator.ActiveCfg = Release|Any CPU
+		{B9B0D41C-1C07-4590-A919-5865E741B2EA}.Release|iPhoneSimulator.Build.0 = Release|Any CPU
+		{B9B0D41C-1C07-4590-A919-5865E741B2EA}.Debug|iPhone.ActiveCfg = Debug|Any CPU
+		{B9B0D41C-1C07-4590-A919-5865E741B2EA}.Debug|iPhone.Build.0 = Debug|Any CPU
+		{62336DF0-60D8-478F-8140-B3CB089B417E}.Debug|Any CPU.ActiveCfg = Debug|iPhoneSimulator
+		{62336DF0-60D8-478F-8140-B3CB089B417E}.Debug|Any CPU.Build.0 = Debug|iPhoneSimulator
+		{62336DF0-60D8-478F-8140-B3CB089B417E}.Release|Any CPU.ActiveCfg = Release|iPhone
+		{62336DF0-60D8-478F-8140-B3CB089B417E}.Release|Any CPU.Build.0 = Release|iPhone
+		{62336DF0-60D8-478F-8140-B3CB089B417E}.Debug|iPhoneSimulator.ActiveCfg = Debug|iPhoneSimulator
+		{62336DF0-60D8-478F-8140-B3CB089B417E}.Debug|iPhoneSimulator.Build.0 = Debug|iPhoneSimulator
+		{62336DF0-60D8-478F-8140-B3CB089B417E}.Release|iPhone.ActiveCfg = Release|iPhone
+		{62336DF0-60D8-478F-8140-B3CB089B417E}.Release|iPhone.Build.0 = Release|iPhone
+		{62336DF0-60D8-478F-8140-B3CB089B417E}.Release|iPhoneSimulator.ActiveCfg = Release|iPhoneSimulator
+		{62336DF0-60D8-478F-8140-B3CB089B417E}.Release|iPhoneSimulator.Build.0 = Release|iPhoneSimulator
+		{62336DF0-60D8-478F-8140-B3CB089B417E}.Debug|iPhone.ActiveCfg = Debug|iPhone
+		{62336DF0-60D8-478F-8140-B3CB089B417E}.Debug|iPhone.Build.0 = Debug|iPhone
+	EndGlobalSection
+EndGlobal

examples/csharp/HelloworldXamarin/HelloworldXamarin/Helloworld.cs

@@ -0,0 +1,286 @@
+// Generated by the protocol buffer compiler.  DO NOT EDIT!
+// source: helloworld.proto
+#pragma warning disable 1591, 0612, 3021
+#region Designer generated code
+
+using pb = global::Google.Protobuf;
+using pbc = global::Google.Protobuf.Collections;
+using pbr = global::Google.Protobuf.Reflection;
+using scg = global::System.Collections.Generic;
+namespace Helloworld {
+
+  /// <summary>Holder for reflection information generated from helloworld.proto</summary>
+  public static partial class HelloworldReflection {
+
+    #region Descriptor
+    /// <summary>File descriptor for helloworld.proto</summary>
+    public static pbr::FileDescriptor Descriptor {
+      get { return descriptor; }
+    }
+    private static pbr::FileDescriptor descriptor;
+
+    static HelloworldReflection() {
+      byte[] descriptorData = global::System.Convert.FromBase64String(
+          string.Concat(
+            "ChBoZWxsb3dvcmxkLnByb3RvEgpoZWxsb3dvcmxkIhwKDEhlbGxvUmVxdWVz",
+            "dBIMCgRuYW1lGAEgASgJIh0KCkhlbGxvUmVwbHkSDwoHbWVzc2FnZRgBIAEo",
+            "CTJJCgdHcmVldGVyEj4KCFNheUhlbGxvEhguaGVsbG93b3JsZC5IZWxsb1Jl",
+            "cXVlc3QaFi5oZWxsb3dvcmxkLkhlbGxvUmVwbHkiAEI2Chtpby5ncnBjLmV4",
+            "YW1wbGVzLmhlbGxvd29ybGRCD0hlbGxvV29ybGRQcm90b1ABogIDSExXYgZw",
+            "cm90bzM="));
+      descriptor = pbr::FileDescriptor.FromGeneratedCode(descriptorData,
+          new pbr::FileDescriptor[] { },
+          new pbr::GeneratedClrTypeInfo(null, new pbr::GeneratedClrTypeInfo[] {
+            new pbr::GeneratedClrTypeInfo(typeof(global::Helloworld.HelloRequest), global::Helloworld.HelloRequest.Parser, new[]{ "Name" }, null, null, null),
+            new pbr::GeneratedClrTypeInfo(typeof(global::Helloworld.HelloReply), global::Helloworld.HelloReply.Parser, new[]{ "Message" }, null, null, null)
+          }));
+    }
+    #endregion
+
+  }
+  #region Messages
+  /// <summary>
+  /// The request message containing the user's name.
+  /// </summary>
+  public sealed partial class HelloRequest : pb::IMessage<HelloRequest> {
+    private static readonly pb::MessageParser<HelloRequest> _parser = new pb::MessageParser<HelloRequest>(() => new HelloRequest());
+    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+    public static pb::MessageParser<HelloRequest> Parser { get { return _parser; } }
+
+    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+    public static pbr::MessageDescriptor Descriptor {
+      get { return global::Helloworld.HelloworldReflection.Descriptor.MessageTypes[0]; }
+    }
+
+    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+    pbr::MessageDescriptor pb::IMessage.Descriptor {
+      get { return Descriptor; }
+    }
+
+    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+    public HelloRequest() {
+      OnConstruction();
+    }
+
+    partial void OnConstruction();
+
+    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+    public HelloRequest(HelloRequest other) : this() {
+      name_ = other.name_;
+    }
+
+    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+    public HelloRequest Clone() {
+      return new HelloRequest(this);
+    }
+
+    /// <summary>Field number for the "name" field.</summary>
+    public const int NameFieldNumber = 1;
+    private string name_ = "";
+    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+    public string Name {
+      get { return name_; }
+      set {
+        name_ = pb::ProtoPreconditions.CheckNotNull(value, "value");
+      }
+    }
+
+    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+    public override bool Equals(object other) {
+      return Equals(other as HelloRequest);
+    }
+
+    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+    public bool Equals(HelloRequest other) {
+      if (ReferenceEquals(other, null)) {
+        return false;
+      }
+      if (ReferenceEquals(other, this)) {
+        return true;
+      }
+      if (Name != other.Name) return false;
+      return true;
+    }
+
+    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+    public override int GetHashCode() {
+      int hash = 1;
+      if (Name.Length != 0) hash ^= Name.GetHashCode();
+      return hash;
+    }
+
+    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+    public override string ToString() {
+      return pb::JsonFormatter.ToDiagnosticString(this);
+    }
+
+    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+    public void WriteTo(pb::CodedOutputStream output) {
+      if (Name.Length != 0) {
+        output.WriteRawTag(10);
+        output.WriteString(Name);
+      }
+    }
+
+    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+    public int CalculateSize() {
+      int size = 0;
+      if (Name.Length != 0) {
+        size += 1 + pb::CodedOutputStream.ComputeStringSize(Name);
+      }
+      return size;
+    }
+
+    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+    public void MergeFrom(HelloRequest other) {
+      if (other == null) {
+        return;
+      }
+      if (other.Name.Length != 0) {
+        Name = other.Name;
+      }
+    }
+
+    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+    public void MergeFrom(pb::CodedInputStream input) {
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            input.SkipLastField();
+            break;
+          case 10: {
+            Name = input.ReadString();
+            break;
+          }
+        }
+      }
+    }
+
+  }
+
+  /// <summary>
+  /// The response message containing the greetings
+  /// </summary>
+  public sealed partial class HelloReply : pb::IMessage<HelloReply> {
+    private static readonly pb::MessageParser<HelloReply> _parser = new pb::MessageParser<HelloReply>(() => new HelloReply());
+    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+    public static pb::MessageParser<HelloReply> Parser { get { return _parser; } }
+
+    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+    public static pbr::MessageDescriptor Descriptor {
+      get { return global::Helloworld.HelloworldReflection.Descriptor.MessageTypes[1]; }
+    }
+
+    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+    pbr::MessageDescriptor pb::IMessage.Descriptor {
+      get { return Descriptor; }
+    }
+
+    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+    public HelloReply() {
+      OnConstruction();
+    }
+
+    partial void OnConstruction();
+
+    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+    public HelloReply(HelloReply other) : this() {
+      message_ = other.message_;
+    }
+
+    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+    public HelloReply Clone() {
+      return new HelloReply(this);
+    }
+
+    /// <summary>Field number for the "message" field.</summary>
+    public const int MessageFieldNumber = 1;
+    private string message_ = "";
+    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+    public string Message {
+      get { return message_; }
+      set {
+        message_ = pb::ProtoPreconditions.CheckNotNull(value, "value");
+      }
+    }
+
+    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+    public override bool Equals(object other) {
+      return Equals(other as HelloReply);
+    }
+
+    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+    public bool Equals(HelloReply other) {
+      if (ReferenceEquals(other, null)) {
+        return false;
+      }
+      if (ReferenceEquals(other, this)) {
+        return true;
+      }
+      if (Message != other.Message) return false;
+      return true;
+    }
+
+    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+    public override int GetHashCode() {
+      int hash = 1;
+      if (Message.Length != 0) hash ^= Message.GetHashCode();
+      return hash;
+    }
+
+    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+    public override string ToString() {
+      return pb::JsonFormatter.ToDiagnosticString(this);
+    }
+
+    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+    public void WriteTo(pb::CodedOutputStream output) {
+      if (Message.Length != 0) {
+        output.WriteRawTag(10);
+        output.WriteString(Message);
+      }
+    }
+
+    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+    public int CalculateSize() {
+      int size = 0;
+      if (Message.Length != 0) {
+        size += 1 + pb::CodedOutputStream.ComputeStringSize(Message);
+      }
+      return size;
+    }
+
+    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+    public void MergeFrom(HelloReply other) {
+      if (other == null) {
+        return;
+      }
+      if (other.Message.Length != 0) {
+        Message = other.Message;
+      }
+    }
+
+    [global::System.Diagnostics.DebuggerNonUserCodeAttribute]
+    public void MergeFrom(pb::CodedInputStream input) {
+      uint tag;
+      while ((tag = input.ReadTag()) != 0) {
+        switch(tag) {
+          default:
+            input.SkipLastField();
+            break;
+          case 10: {
+            Message = input.ReadString();
+            break;
+          }
+        }
+      }
+    }
+
+  }
+
+  #endregion
+
+}
+
+#endregion Designer generated code

examples/csharp/HelloworldXamarin/HelloworldXamarin/HelloworldGrpc.cs

@@ -0,0 +1,150 @@
+// Generated by the protocol buffer compiler.  DO NOT EDIT!
+// source: helloworld.proto
+// Original file comments:
+// Copyright 2015 gRPC authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+#pragma warning disable 1591
+#region Designer generated code
+
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+using grpc = global::Grpc.Core;
+
+namespace Helloworld {
+  /// <summary>
+  /// The greeting service definition.
+  /// </summary>
+  public static partial class Greeter
+  {
+    static readonly string __ServiceName = "helloworld.Greeter";
+
+    static readonly grpc::Marshaller<global::Helloworld.HelloRequest> __Marshaller_HelloRequest = grpc::Marshallers.Create((arg) => global::Google.Protobuf.MessageExtensions.ToByteArray(arg), global::Helloworld.HelloRequest.Parser.ParseFrom);
+    static readonly grpc::Marshaller<global::Helloworld.HelloReply> __Marshaller_HelloReply = grpc::Marshallers.Create((arg) => global::Google.Protobuf.MessageExtensions.ToByteArray(arg), global::Helloworld.HelloReply.Parser.ParseFrom);
+
+    static readonly grpc::Method<global::Helloworld.HelloRequest, global::Helloworld.HelloReply> __Method_SayHello = new grpc::Method<global::Helloworld.HelloRequest, global::Helloworld.HelloReply>(
+        grpc::MethodType.Unary,
+        __ServiceName,
+        "SayHello",
+        __Marshaller_HelloRequest,
+        __Marshaller_HelloReply);
+
+    /// <summary>Service descriptor</summary>
+    public static global::Google.Protobuf.Reflection.ServiceDescriptor Descriptor
+    {
+      get { return global::Helloworld.HelloworldReflection.Descriptor.Services[0]; }
+    }
+
+    /// <summary>Base class for server-side implementations of Greeter</summary>
+    public abstract partial class GreeterBase
+    {
+      /// <summary>
+      /// Sends a greeting
+      /// </summary>
+      /// <param name="request">The request received from the client.</param>
+      /// <param name="context">The context of the server-side call handler being invoked.</param>
+      /// <returns>The response to send back to the client (wrapped by a task).</returns>
+      public virtual global::System.Threading.Tasks.Task<global::Helloworld.HelloReply> SayHello(global::Helloworld.HelloRequest request, grpc::ServerCallContext context)
+      {
+        throw new grpc::RpcException(new grpc::Status(grpc::StatusCode.Unimplemented, ""));
+      }
+
+    }
+
+    /// <summary>Client for Greeter</summary>
+    public partial class GreeterClient : grpc::ClientBase<GreeterClient>
+    {
+      /// <summary>Creates a new client for Greeter</summary>
+      /// <param name="channel">The channel to use to make remote calls.</param>
+      public GreeterClient(grpc::Channel channel) : base(channel)
+      {
+      }
+      /// <summary>Creates a new client for Greeter that uses a custom <c>CallInvoker</c>.</summary>
+      /// <param name="callInvoker">The callInvoker to use to make remote calls.</param>
+      public GreeterClient(grpc::CallInvoker callInvoker) : base(callInvoker)
+      {
+      }
+      /// <summary>Protected parameterless constructor to allow creation of test doubles.</summary>
+      protected GreeterClient() : base()
+      {
+      }
+      /// <summary>Protected constructor to allow creation of configured clients.</summary>
+      /// <param name="configuration">The client configuration.</param>
+      protected GreeterClient(ClientBaseConfiguration configuration) : base(configuration)
+      {
+      }
+
+      /// <summary>
+      /// Sends a greeting
+      /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="headers">The initial metadata to send with the call. This parameter is optional.</param>
+      /// <param name="deadline">An optional deadline for the call. The call will be cancelled if deadline is hit.</param>
+      /// <param name="cancellationToken">An optional token for canceling the call.</param>
+      /// <returns>The response received from the server.</returns>
+      public virtual global::Helloworld.HelloReply SayHello(global::Helloworld.HelloRequest request, grpc::Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken))
+      {
+        return SayHello(request, new grpc::CallOptions(headers, deadline, cancellationToken));
+      }
+      /// <summary>
+      /// Sends a greeting
+      /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="options">The options for the call.</param>
+      /// <returns>The response received from the server.</returns>
+      public virtual global::Helloworld.HelloReply SayHello(global::Helloworld.HelloRequest request, grpc::CallOptions options)
+      {
+        return CallInvoker.BlockingUnaryCall(__Method_SayHello, null, options, request);
+      }
+      /// <summary>
+      /// Sends a greeting
+      /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="headers">The initial metadata to send with the call. This parameter is optional.</param>
+      /// <param name="deadline">An optional deadline for the call. The call will be cancelled if deadline is hit.</param>
+      /// <param name="cancellationToken">An optional token for canceling the call.</param>
+      /// <returns>The call object.</returns>
+      public virtual grpc::AsyncUnaryCall<global::Helloworld.HelloReply> SayHelloAsync(global::Helloworld.HelloRequest request, grpc::Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken))
+      {
+        return SayHelloAsync(request, new grpc::CallOptions(headers, deadline, cancellationToken));
+      }
+      /// <summary>
+      /// Sends a greeting
+      /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="options">The options for the call.</param>
+      /// <returns>The call object.</returns>
+      public virtual grpc::AsyncUnaryCall<global::Helloworld.HelloReply> SayHelloAsync(global::Helloworld.HelloRequest request, grpc::CallOptions options)
+      {
+        return CallInvoker.AsyncUnaryCall(__Method_SayHello, null, options, request);
+      }
+      /// <summary>Creates a new instance of client from given <c>ClientBaseConfiguration</c>.</summary>
+      protected override GreeterClient NewInstance(ClientBaseConfiguration configuration)
+      {
+        return new GreeterClient(configuration);
+      }
+    }
+
+    /// <summary>Creates service definition that can be registered with a server</summary>
+    /// <param name="serviceImpl">An object implementing the server-side handling logic.</param>
+    public static grpc::ServerServiceDefinition BindService(GreeterBase serviceImpl)
+    {
+      return grpc::ServerServiceDefinition.CreateBuilder()
+          .AddMethod(__Method_SayHello, serviceImpl.SayHello).Build();
+    }
+
+  }
+}
+#endregion

examples/csharp/HelloworldXamarin/HelloworldXamarin/HelloworldXamarin.projitems

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup>
+    <MSBuildAllProjects>$(MSBuildAllProjects);$(MSBuildThisFileFullPath)</MSBuildAllProjects>
+    <HasSharedItems>true</HasSharedItems>
+    <SharedGUID>{42FFF3D8-934F-4475-8E68-08DA340BF6E8}</SharedGUID>
+  </PropertyGroup>
+  <PropertyGroup Label="Configuration">
+    <Import_RootNamespace>HelloworldXamarin</Import_RootNamespace>
+  </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="$(MSBuildThisFileDirectory)Helloworld.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)HelloworldGrpc.cs" />
+  </ItemGroup>
+</Project>

examples/csharp/HelloworldXamarin/HelloworldXamarin/HelloworldXamarin.shproj

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup>
+    <ProjectGuid>{42FFF3D8-934F-4475-8E68-08DA340BF6E8}</ProjectGuid>
+  </PropertyGroup>
+  <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
+  <Import Project="$(MSBuildExtensionsPath32)\Microsoft\VisualStudio\v$(VisualStudioVersion)\CodeSharing\Microsoft.CodeSharing.Common.Default.props" />
+  <Import Project="$(MSBuildExtensionsPath32)\Microsoft\VisualStudio\v$(VisualStudioVersion)\CodeSharing\Microsoft.CodeSharing.Common.props" />
+  <Import Project="HelloworldXamarin.projitems" Label="Shared" />
+  <Import Project="$(MSBuildExtensionsPath32)\Microsoft\VisualStudio\v$(VisualStudioVersion)\CodeSharing\Microsoft.CodeSharing.CSharp.targets" />
+</Project>

examples/csharp/HelloworldXamarin/README.md

@@ -0,0 +1,35 @@
+gRPC C# on Xamarin
+========================
+
+EXPERIMENTAL ONLY
+-------------
+Support of the Xamarin platform is currently experimental.
+The example depends on experimental Grpc.Core nuget package that hasn't
+been officially released and is only available via the [daily builds](https://packages.grpc.io/)
+source.
+
+BACKGROUND
+-------------
+The example project supports Xamarin.Android and Xamarin.iOS
+
+For this sample, we've already generated the server and client stubs from [helloworld.proto][].
+
+PREREQUISITES
+-------------
+
+- The latest version Xamarin Studio or Visual Studio 2017 with Xamarin support installed.
+
+BUILD
+-------
+
+- Open the `HelloworldXamarin.sln` in Visual Studio (or Xamarin Studio)
+- Build the solution (Build -> Build All)
+
+Try it!
+-------
+
+You can deploy the example apps directly through Xamarin Studio IDE.
+Deployments can target both Android and iOS (both support physical device
+deployment as well as simulator).
+
+[helloworld.proto]:../../protos/helloworld.proto

examples/csharp/HelloworldXamarin/iOS/AppDelegate.cs

@@ -0,0 +1,77 @@
+#region Copyright notice and license
+
+// Copyright 2018 The gRPC Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#endregion
+
+using Foundation;
+using UIKit;
+
+namespace HelloworldXamarin.iOS
+{
+    // The UIApplicationDelegate for the application. This class is responsible for launching the
+    // User Interface of the application, as well as listening (and optionally responding) to application events from iOS.
+    [Register("AppDelegate")]
+    public class AppDelegate : UIApplicationDelegate
+    {
+        // class-level declarations
+
+        public override UIWindow Window
+        {
+            get;
+            set;
+        }
+
+        public override bool FinishedLaunching(UIApplication application, NSDictionary launchOptions)
+        {
+            // Override point for customization after application launch.
+            // If not required for your application you can safely delete this method
+
+            return true;
+        }
+
+        public override void OnResignActivation(UIApplication application)
+        {
+            // Invoked when the application is about to move from active to inactive state.
+            // This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) 
+            // or when the user quits the application and it begins the transition to the background state.
+            // Games should use this method to pause the game.
+        }
+
+        public override void DidEnterBackground(UIApplication application)
+        {
+            // Use this method to release shared resources, save user data, invalidate timers and store the application state.
+            // If your application supports background exection this method is called instead of WillTerminate when the user quits.
+        }
+
+        public override void WillEnterForeground(UIApplication application)
+        {
+            // Called as part of the transiton from background to active state.
+            // Here you can undo many of the changes made on entering the background.
+        }
+
+        public override void OnActivated(UIApplication application)
+        {
+            // Restart any tasks that were paused (or not yet started) while the application was inactive. 
+            // If the application was previously in the background, optionally refresh the user interface.
+        }
+
+        public override void WillTerminate(UIApplication application)
+        {
+            // Called when the application is about to terminate. Save data, if needed. See also DidEnterBackground.
+        }
+    }
+}
+

examples/csharp/HelloworldXamarin/iOS/Assets.xcassets/AppIcon.appiconset/Contents.json

@@ -0,0 +1,202 @@
+{
+  "images" : [
+    {
+      "idiom" : "iphone",
+      "size" : "20x20",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "iphone",
+      "size" : "20x20",
+      "scale" : "3x"
+    },
+    {
+      "idiom" : "iphone",
+      "size" : "29x29",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "iphone",
+      "size" : "29x29",
+      "scale" : "3x"
+    },
+    {
+      "idiom" : "iphone",
+      "size" : "40x40",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "iphone",
+      "size" : "40x40",
+      "scale" : "3x"
+    },
+    {
+      "idiom" : "iphone",
+      "size" : "60x60",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "iphone",
+      "size" : "60x60",
+      "scale" : "3x"
+    },
+    {
+      "idiom" : "ipad",
+      "size" : "20x20",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "ipad",
+      "size" : "20x20",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "ipad",
+      "size" : "29x29",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "ipad",
+      "size" : "29x29",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "ipad",
+      "size" : "40x40",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "ipad",
+      "size" : "40x40",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "ipad",
+      "size" : "76x76",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "ipad",
+      "size" : "76x76",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "ipad",
+      "size" : "83.5x83.5",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "ios-marketing",
+      "size" : "1024x1024",
+      "scale" : "1x"
+    },
+    {
+      "size" : "24x24",
+      "idiom" : "watch",
+      "scale" : "2x",
+      "role" : "notificationCenter",
+      "subtype" : "38mm"
+    },
+    {
+      "size" : "27.5x27.5",
+      "idiom" : "watch",
+      "scale" : "2x",
+      "role" : "notificationCenter",
+      "subtype" : "42mm"
+    },
+    {
+      "size" : "29x29",
+      "idiom" : "watch",
+      "role" : "companionSettings",
+      "scale" : "2x"
+    },
+    {
+      "size" : "29x29",
+      "idiom" : "watch",
+      "role" : "companionSettings",
+      "scale" : "3x"
+    },
+    {
+      "size" : "40x40",
+      "idiom" : "watch",
+      "scale" : "2x",
+      "role" : "appLauncher",
+      "subtype" : "38mm"
+    },
+    {
+      "size" : "44x44",
+      "idiom" : "watch",
+      "scale" : "2x",
+      "role" : "longLook",
+      "subtype" : "42mm"
+    },
+    {
+      "size" : "86x86",
+      "idiom" : "watch",
+      "scale" : "2x",
+      "role" : "quickLook",
+      "subtype" : "38mm"
+    },
+    {
+      "size" : "98x98",
+      "idiom" : "watch",
+      "scale" : "2x",
+      "role" : "quickLook",
+      "subtype" : "42mm"
+    },
+    {
+      "idiom" : "mac",
+      "size" : "16x16",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "mac",
+      "size" : "16x16",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "mac",
+      "size" : "32x32",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "mac",
+      "size" : "32x32",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "mac",
+      "size" : "128x128",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "mac",
+      "size" : "128x128",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "mac",
+      "size" : "256x256",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "mac",
+      "size" : "256x256",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "mac",
+      "size" : "512x512",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "mac",
+      "size" : "512x512",
+      "scale" : "2x"
+    }
+  ],
+  "info" : {
+    "version" : 1,
+    "author" : "xcode"
+  }
+}

examples/csharp/HelloworldXamarin/iOS/Assets.xcassets/Contents.json

@@ -0,0 +1,6 @@
+{
+  "info" : {
+    "version" : 1,
+    "author" : "xcode"
+  }
+}

examples/csharp/HelloworldXamarin/iOS/Entitlements.plist

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+</dict>
+</plist>

examples/csharp/HelloworldXamarin/iOS/HelloworldXamarin.iOS.csproj

@@ -0,0 +1,126 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project DefaultTargets="Build" ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup>
+    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
+    <Platform Condition=" '$(Platform)' == '' ">iPhoneSimulator</Platform>
+    <ProjectGuid>{62336DF0-60D8-478F-8140-B3CB089B417E}</ProjectGuid>
+    <ProjectTypeGuids>{FEACFBD2-3405-455C-9665-78FE426C6842};{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}</ProjectTypeGuids>
+    <OutputType>Exe</OutputType>
+    <RootNamespace>HelloworldXamarin.iOS</RootNamespace>
+    <AssemblyName>HelloworldXamarin.iOS</AssemblyName>
+    <IPhoneResourcePrefix>Resources</IPhoneResourcePrefix>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|iPhoneSimulator' ">
+    <DebugSymbols>true</DebugSymbols>
+    <DebugType>full</DebugType>
+    <Optimize>false</Optimize>
+    <OutputPath>bin\iPhoneSimulator\Debug</OutputPath>
+    <DefineConstants>DEBUG;ENABLE_TEST_CLOUD;</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+    <CodesignKey>iPhone Developer</CodesignKey>
+    <MtouchDebug>true</MtouchDebug>
+    <MtouchNoSymbolStrip>true</MtouchNoSymbolStrip>
+    <MtouchFastDev>true</MtouchFastDev>
+    <IOSDebuggerPort>45216</IOSDebuggerPort>
+    <MtouchLink>None</MtouchLink>
+    <MtouchArch>x86_64</MtouchArch>
+    <MtouchHttpClientHandler>HttpClientHandler</MtouchHttpClientHandler>
+    <PlatformTarget>x86</PlatformTarget>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|iPhone' ">
+    <DebugType>pdbonly</DebugType>
+    <Optimize>true</Optimize>
+    <OutputPath>bin\iPhone\Release</OutputPath>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+    <CodesignKey>iPhone Developer</CodesignKey>
+    <MtouchFloat32>true</MtouchFloat32>
+    <CodesignEntitlements>Entitlements.plist</CodesignEntitlements>
+    <MtouchLink>SdkOnly</MtouchLink>
+    <MtouchArch>ARM64</MtouchArch>
+    <MtouchHttpClientHandler>HttpClientHandler</MtouchHttpClientHandler>
+    <PlatformTarget>x86</PlatformTarget>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|iPhoneSimulator' ">
+    <DebugType>pdbonly</DebugType>
+    <Optimize>true</Optimize>
+    <OutputPath>bin\iPhoneSimulator\Release</OutputPath>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+    <CodesignKey>iPhone Developer</CodesignKey>
+    <MtouchNoSymbolStrip>true</MtouchNoSymbolStrip>
+    <MtouchLink>None</MtouchLink>
+    <MtouchArch>x86_64</MtouchArch>
+    <MtouchHttpClientHandler>HttpClientHandler</MtouchHttpClientHandler>
+    <PlatformTarget>x86</PlatformTarget>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|iPhone' ">
+    <DebugSymbols>true</DebugSymbols>
+    <DebugType>full</DebugType>
+    <Optimize>false</Optimize>
+    <OutputPath>bin\iPhone\Debug</OutputPath>
+    <DefineConstants>DEBUG;ENABLE_TEST_CLOUD;</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+    <CodesignKey>iPhone Developer</CodesignKey>
+    <DeviceSpecificBuild>true</DeviceSpecificBuild>
+    <MtouchDebug>true</MtouchDebug>
+    <MtouchNoSymbolStrip>true</MtouchNoSymbolStrip>
+    <MtouchFastDev>true</MtouchFastDev>
+    <MtouchFloat32>true</MtouchFloat32>
+    <CodesignEntitlements>Entitlements.plist</CodesignEntitlements>
+    <IOSDebuggerPort>35164</IOSDebuggerPort>
+    <MtouchLink>SdkOnly</MtouchLink>
+    <MtouchArch>ARM64</MtouchArch>
+    <MtouchHttpClientHandler>HttpClientHandler</MtouchHttpClientHandler>
+    <PlatformTarget>x86</PlatformTarget>
+  </PropertyGroup>
+  <ItemGroup>
+    <Reference Include="System" />
+    <Reference Include="System.Xml" />
+    <Reference Include="System.Core" />
+    <Reference Include="Xamarin.iOS" />
+    <Reference Include="System.IO.Compression" />
+    <Reference Include="System.Net.Http" />
+    <Reference Include="System.Runtime.Loader">
+      <HintPath>..\packages\System.Runtime.Loader.4.0.0\lib\netstandard1.5\System.Runtime.Loader.dll</HintPath>
+    </Reference>
+    <Reference Include="System.Interactive.Async">
+      <HintPath>..\packages\System.Interactive.Async.3.1.1\lib\netstandard1.3\System.Interactive.Async.dll</HintPath>
+    </Reference>
+    <Reference Include="Grpc.Core">
+      <HintPath>..\packages\Grpc.Core.1.15.0-dev\lib\netstandard1.5\Grpc.Core.dll</HintPath>
+    </Reference>
+    <Reference Include="Google.Protobuf">
+      <HintPath>..\packages\Google.Protobuf.3.6.0\lib\netstandard1.0\Google.Protobuf.dll</HintPath>
+    </Reference>
+  </ItemGroup>
+  <ItemGroup>
+    <ImageAsset Include="Assets.xcassets\AppIcon.appiconset\Contents.json" />
+    <ImageAsset Include="Assets.xcassets\Contents.json" />
+  </ItemGroup>
+  <ItemGroup>
+    <Folder Include="Resources\" />
+  </ItemGroup>
+  <ItemGroup>
+    <InterfaceDefinition Include="LaunchScreen.storyboard" />
+    <InterfaceDefinition Include="Main.storyboard" />
+  </ItemGroup>
+  <ItemGroup>
+    <None Include="Info.plist" />
+    <None Include="Entitlements.plist" />
+    <None Include="packages.config" />
+  </ItemGroup>
+  <ItemGroup>
+    <Compile Include="Main.cs" />
+    <Compile Include="AppDelegate.cs" />
+    <Compile Include="ViewController.cs" />
+    <Compile Include="ViewController.designer.cs">
+      <DependentUpon>ViewController.cs</DependentUpon>
+    </Compile>
+  </ItemGroup>
+  <Import Project="..\HelloworldXamarin\HelloworldXamarin.projitems" Label="Shared" Condition="Exists('..\HelloworldXamarin\HelloworldXamarin.projitems')" />
+  <Import Project="$(MSBuildExtensionsPath)\Xamarin\iOS\Xamarin.iOS.CSharp.targets" />
+  <Import Project="..\packages\Grpc.Core.1.15.0-dev\build\Xamarin.iOS\Grpc.Core.targets" Condition="Exists('..\packages\Grpc.Core.1.15.0-dev\build\Xamarin.iOS\Grpc.Core.targets')" />
+</Project>

examples/csharp/HelloworldXamarin/iOS/Info.plist

@@ -0,0 +1,48 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>CFBundleName</key>
+	<string>HelloworldXamarin</string>
+	<key>CFBundleIdentifier</key>
+	<string>io.grpc.examples.HelloworldXamarin</string>
+	<key>CFBundleShortVersionString</key>
+	<string>1.0</string>
+	<key>CFBundleVersion</key>
+	<string>1.0</string>
+	<key>LSRequiresIPhoneOS</key>
+	<true/>
+	<key>MinimumOSVersion</key>
+	<string>8.0</string>
+	<key>UIDeviceFamily</key>
+	<array>
+		<integer>1</integer>
+		<integer>2</integer>
+	</array>
+	<key>UILaunchStoryboardName</key>
+	<string>LaunchScreen</string>
+	<key>UIMainStoryboardFile</key>
+	<string>Main</string>
+	<key>UIMainStoryboardFile~ipad</key>
+	<string>Main</string>
+	<key>UIRequiredDeviceCapabilities</key>
+	<array>
+		<string>armv7</string>
+	</array>
+	<key>UISupportedInterfaceOrientations</key>
+	<array>
+		<string>UIInterfaceOrientationPortrait</string>
+		<string>UIInterfaceOrientationLandscapeLeft</string>
+		<string>UIInterfaceOrientationLandscapeRight</string>
+	</array>
+	<key>UISupportedInterfaceOrientations~ipad</key>
+	<array>
+		<string>UIInterfaceOrientationPortrait</string>
+		<string>UIInterfaceOrientationPortraitUpsideDown</string>
+		<string>UIInterfaceOrientationLandscapeLeft</string>
+		<string>UIInterfaceOrientationLandscapeRight</string>
+	</array>
+	<key>XSAppIconAssets</key>
+	<string>Assets.xcassets/AppIcon.appiconset</string>
+</dict>
+</plist>

examples/csharp/HelloworldXamarin/iOS/LaunchScreen.storyboard

@@ -0,0 +1,27 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="9532" systemVersion="15D21" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" launchScreen="YES" useTraitCollections="YES" initialViewController="01J-lp-oVM">
+    <dependencies>
+        <deployment identifier="iOS" />
+        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="9530" />
+    </dependencies>
+    <scenes>
+        <!--View Controller-->
+        <scene sceneID="EHf-IW-A2E">
+            <objects>
+                <viewController id="01J-lp-oVM" sceneMemberID="viewController">
+                    <layoutGuides>
+                        <viewControllerLayoutGuide type="top" id="Llm-lL-Icb" />
+                        <viewControllerLayoutGuide type="bottom" id="xb3-aO-Qok" />
+                    </layoutGuides>
+                    <view key="view" contentMode="scaleToFill" id="Ze5-6b-2t3">
+                        <rect key="frame" x="0.0" y="0.0" width="600" height="600" />
+                        <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES" />
+                        <color key="backgroundColor" white="1" alpha="1" colorSpace="custom" customColorSpace="calibratedWhite" />
+                    </view>
+                </viewController>
+                <placeholder placeholderIdentifier="IBFirstResponder" id="iYj-Kq-Ea1" userLabel="First Responder" sceneMemberID="firstResponder" />
+            </objects>
+            <point key="canvasLocation" x="53" y="375" />
+        </scene>
+    </scenes>
+</document>

examples/csharp/HelloworldXamarin/iOS/Main.cs

@@ -0,0 +1,38 @@
+#region Copyright notice and license
+
+// Copyright 2018 The gRPC Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#endregion
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+using Foundation;
+using UIKit;
+
+namespace HelloworldXamarin.iOS
+{
+    public class Application
+    {
+        // This is the main entry point of the application.
+        static void Main(string[] args)
+        {
+            // if you want to use a different Application Delegate class from "AppDelegate"
+            // you can specify it here.
+            UIApplication.Main(args, null, "AppDelegate");
+        }
+    }
+}

examples/csharp/HelloworldXamarin/iOS/Main.storyboard

@@ -0,0 +1,40 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="6750" systemVersion="14C109" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" initialViewController="BYZ-38-t0r">
+    <dependencies>
+        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="6735" />
+    </dependencies>
+    <scenes>
+        <!--View Controller-->
+        <scene sceneID="tne-QT-ifu">
+            <objects>
+                <viewController id="BYZ-38-t0r" customClass="ViewController" sceneMemberID="viewController">
+                    <layoutGuides>
+                        <viewControllerLayoutGuide type="top" id="y3c-jy-aDJ" />
+                        <viewControllerLayoutGuide type="bottom" id="wfy-db-euE" />
+                    </layoutGuides>
+                    <view key="view" contentMode="scaleToFill" id="8bC-Xf-vdC">
+                        <rect key="frame" x="0.0" y="0.0" width="600" height="600" />
+                        <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES" />
+                        <subviews>
+                            <button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="roundedRect" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="oBE-Ac-vcx">
+                                <rect key="frame" x="224" y="285" width="152" height="30" />
+                                <state key="normal" title="Hello World, Click Me!">
+                                    <color key="titleShadowColor" white="0.5" alpha="1" colorSpace="calibratedWhite" />
+                                </state>
+                            </button>
+                        </subviews>
+                        <color key="backgroundColor" white="1" alpha="1" colorSpace="custom" customColorSpace="calibratedWhite" />
+                        <constraints>
+                            <constraint firstItem="oBE-Ac-vcx" firstAttribute="centerX" secondItem="8bC-Xf-vdC" secondAttribute="centerX" id="HiD-uS-i16" />
+                            <constraint firstItem="oBE-Ac-vcx" firstAttribute="centerY" secondItem="8bC-Xf-vdC" secondAttribute="centerY" id="YgX-7e-bMc" />
+                        </constraints>
+                    </view>
+                    <connections>
+                        <outlet property="Button" destination="oBE-Ac-vcx" id="OkX-0Z-gth" />
+                    </connections>
+                </viewController>
+                <placeholder placeholderIdentifier="IBFirstResponder" id="dkx-z0-nzr" sceneMemberID="firstResponder" />
+            </objects>
+        </scene>
+    </scenes>
+</document>

examples/csharp/HelloworldXamarin/iOS/ViewController.cs

@@ -0,0 +1,91 @@
+#region Copyright notice and license
+
+// Copyright 2018 The gRPC Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#endregion
+
+using System;
+using System.Threading.Tasks;
+
+using Grpc.Core;
+using Helloworld;
+
+using UIKit;
+
+namespace HelloworldXamarin.iOS
+{
+    public partial class ViewController : UIViewController
+    {
+        const int Port = 50051;
+        int count = 1;
+
+        public ViewController(IntPtr handle) : base(handle)
+        {
+        }
+
+        public override void ViewDidLoad()
+        {
+            base.ViewDidLoad();
+
+            // Perform any additional setup after loading the view, typically from a nib.
+            Button.AccessibilityIdentifier = "myButton";
+            Button.TouchUpInside += delegate
+            {
+                var title = SayHello();
+                Button.SetTitle(title, UIControlState.Normal);
+            };
+        }
+
+        public override void DidReceiveMemoryWarning()
+        {
+            base.DidReceiveMemoryWarning();
+            // Release any cached data, images, etc that aren't in use.		
+        }
+
+        private string SayHello()
+        {
+            Server server = new Server
+            {
+                Services = { Greeter.BindService(new GreeterImpl()) },
+                Ports = { new ServerPort("localhost", Port, ServerCredentials.Insecure) }
+            };
+            server.Start();
+
+            Channel channel = new Channel("localhost:50051", ChannelCredentials.Insecure);
+
+            var client = new Greeter.GreeterClient(channel);
+            string user = "Xamarin " + count;
+
+            var reply = client.SayHello(new HelloRequest { Name = user });
+
+            channel.ShutdownAsync().Wait();
+            server.ShutdownAsync().Wait();
+
+            count++;
+
+            return "Greeting: " + reply.Message;
+        }
+
+
+        class GreeterImpl : Greeter.GreeterBase
+        {
+            // Server side handler of the SayHello RPC
+            public override Task<HelloReply> SayHello(HelloRequest request, ServerCallContext context)
+            {
+              return Task.FromResult(new HelloReply { Message = "Hello " + request.Name });
+            }
+        }
+    }
+}

examples/csharp/HelloworldXamarin/iOS/ViewController.designer.cs

@@ -0,0 +1,25 @@
+//		
+// This file has been generated automatically by MonoDevelop to store outlets and		
+// actions made in the Xcode designer. If it is removed, they will be lost.		
+// Manual changes to this file may not be handled correctly.		
+//		
+using Foundation;
+
+namespace HelloworldXamarin.iOS
+{
+    [Register("ViewController")]
+    partial class ViewController
+    {
+        [Outlet]
+        UIKit.UIButton Button { get; set; }
+
+        void ReleaseDesignerOutlets()
+        {
+            if (Button != null)
+            {
+                Button.Dispose();
+                Button = null;
+            }
+        }
+    }
+}

examples/csharp/HelloworldXamarin/iOS/packages.config

@@ -0,0 +1,54 @@
+<?xml version="1.0" encoding="utf-8"?>
+<packages>
+  <package id="Google.Protobuf" version="3.6.0" targetFramework="xamarinios10" />
+  <package id="Grpc.Core" version="1.15.0-dev" targetFramework="xamarinios10" />
+  <package id="Microsoft.NETCore.Platforms" version="1.1.0" targetFramework="xamarinios10" />
+  <package id="Microsoft.Win32.Primitives" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="NETStandard.Library" version="1.6.1" targetFramework="xamarinios10" />
+  <package id="System.AppContext" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.Collections" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.Collections.Concurrent" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.Console" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.Diagnostics.Debug" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.Diagnostics.Tools" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.Diagnostics.Tracing" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.Globalization" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.Globalization.Calendars" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.Interactive.Async" version="3.1.1" targetFramework="xamarinios10" />
+  <package id="System.IO" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.IO.Compression" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.IO.Compression.ZipFile" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.IO.FileSystem" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.IO.FileSystem.Primitives" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.Linq" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.Linq.Expressions" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.Net.Http" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.Net.Primitives" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.Net.Sockets" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.ObjectModel" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.Reflection" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.Reflection.Extensions" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.Reflection.Primitives" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.Resources.ResourceManager" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.Runtime" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.Runtime.Extensions" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.Runtime.Handles" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.Runtime.InteropServices" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.Runtime.InteropServices.RuntimeInformation" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.Runtime.Loader" version="4.0.0" targetFramework="xamarinios10" />
+  <package id="System.Runtime.Numerics" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.Security.Cryptography.Algorithms" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.Security.Cryptography.Encoding" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.Security.Cryptography.Primitives" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.Security.Cryptography.X509Certificates" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.Text.Encoding" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.Text.Encoding.Extensions" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.Text.RegularExpressions" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.Threading" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.Threading.Tasks" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.Threading.Thread" version="4.0.0" targetFramework="xamarinios10" />
+  <package id="System.Threading.ThreadPool" version="4.0.10" targetFramework="xamarinios10" />
+  <package id="System.Threading.Timer" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.Xml.ReaderWriter" version="4.3.0" targetFramework="xamarinios10" />
+  <package id="System.Xml.XDocument" version="4.3.0" targetFramework="xamarinios10" />
+</packages>

examples/node/dynamic_codegen/greeter_client.js

@@ -19,7 +19,16 @@
 var PROTO_PATH = __dirname + '/../../protos/helloworld.proto';
 
 var grpc = require('grpc');
-var hello_proto = grpc.load(PROTO_PATH).helloworld;
+var protoLoader = require('@grpc/proto-loader');
+var packageDefinition = protoLoader.loadSync(
+    PROTO_PATH,
+    {keepCase: true,
+     longs: String,
+     enums: String,
+     defaults: true,
+     oneofs: true
+    });
+var hello_proto = grpc.loadPackageDefinition(packageDefinition).helloworld;
 
 function main() {
   var client = new hello_proto.Greeter('localhost:50051',

examples/node/dynamic_codegen/greeter_server.js

@@ -19,7 +19,16 @@
 var PROTO_PATH = __dirname + '/../../protos/helloworld.proto';
 
 var grpc = require('grpc');
-var hello_proto = grpc.load(PROTO_PATH).helloworld;
+var protoLoader = require('@grpc/proto-loader');
+var packageDefinition = protoLoader.loadSync(
+    PROTO_PATH,
+    {keepCase: true,
+     longs: String,
+     enums: String,
+     defaults: true,
+     oneofs: true
+    });
+var hello_proto = grpc.loadPackageDefinition(packageDefinition).helloworld;
 
 /**
  * Implements the SayHello RPC method.

examples/node/dynamic_codegen/route_guide/route_guide_client.js

@@ -24,7 +24,16 @@ var parseArgs = require('minimist');
 var path = require('path');
 var _ = require('lodash');
 var grpc = require('grpc');
-var routeguide = grpc.load(PROTO_PATH).routeguide;
+var protoLoader = require('@grpc/proto-loader');
+var packageDefinition = protoLoader.loadSync(
+    PROTO_PATH,
+    {keepCase: true,
+     longs: String,
+     enums: String,
+     defaults: true,
+     oneofs: true
+    });
+var routeguide = grpc.loadPackageDefinition(packageDefinition).routeguide;
 var client = new routeguide.RouteGuide('localhost:50051',
                                        grpc.credentials.createInsecure());
 

examples/node/dynamic_codegen/route_guide/route_guide_server.js

@@ -23,7 +23,16 @@ var parseArgs = require('minimist');
 var path = require('path');
 var _ = require('lodash');
 var grpc = require('grpc');
-var routeguide = grpc.load(PROTO_PATH).routeguide;
+var protoLoader = require('@grpc/proto-loader');
+var packageDefinition = protoLoader.loadSync(
+    PROTO_PATH,
+    {keepCase: true,
+     longs: String,
+     enums: String,
+     defaults: true,
+     oneofs: true
+    });
+var routeguide = grpc.loadPackageDefinition(packageDefinition).routeguide;
 
 var COORD_FACTOR = 1e7;
 

examples/node/package.json

@@ -2,9 +2,10 @@
   "name": "grpc-examples",
   "version": "0.1.0",
   "dependencies": {
+    "@grpc/proto-loader": "^0.1.0",
     "async": "^1.5.2",
     "google-protobuf": "^3.0.0",
-    "grpc": "^1.0.0",
+    "grpc": "^1.11.0",
     "lodash": "^4.6.1",
     "minimist": "^1.2.0"
   }

examples/ruby/grpc-demo.gemspec

@@ -18,6 +18,6 @@ Gem::Specification.new do |s|
   s.platform      = Gem::Platform::RUBY
 
   s.add_dependency 'grpc', '~> 1.0'
-
+  s.add_dependency 'multi_json', '~> 1.13.1'
   s.add_development_dependency 'bundler', '~> 1.7'
 end

gRPC-Core.podspec

@@ -802,8 +802,11 @@ Pod::Spec.new do |s|
                       'src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc',
                       'src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver.cc',
                       'src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_posix.cc',
+                      'src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_windows.cc',
                       'src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.cc',
                       'src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_fallback.cc',
+                      'src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_posix.cc',
+                      'src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_windows.cc',
                       'src/core/ext/filters/client_channel/resolver/dns/native/dns_resolver.cc',
                       'src/core/ext/filters/client_channel/resolver/sockaddr/sockaddr_resolver.cc',
                       'src/cpp/ext/filters/census/grpc_context.cc',

grpc.gemspec

@@ -742,8 +742,11 @@ Gem::Specification.new do |s|
   s.files += %w( src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc )
   s.files += %w( src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver.cc )
   s.files += %w( src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_posix.cc )
+  s.files += %w( src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_windows.cc )
   s.files += %w( src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.cc )
   s.files += %w( src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_fallback.cc )
+  s.files += %w( src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_posix.cc )
+  s.files += %w( src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_windows.cc )
   s.files += %w( src/core/ext/filters/client_channel/resolver/dns/native/dns_resolver.cc )
   s.files += %w( src/core/ext/filters/client_channel/resolver/sockaddr/sockaddr_resolver.cc )
   s.files += %w( src/cpp/ext/filters/census/grpc_context.cc )

grpc.gyp

@@ -572,8 +572,11 @@
         'src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc',
         'src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver.cc',
         'src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_posix.cc',
+        'src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_windows.cc',
         'src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.cc',
         'src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_fallback.cc',
+        'src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_posix.cc',
+        'src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_windows.cc',
         'src/core/ext/filters/client_channel/resolver/dns/native/dns_resolver.cc',
         'src/core/ext/filters/client_channel/resolver/sockaddr/sockaddr_resolver.cc',
         'src/cpp/ext/filters/census/grpc_context.cc',
@@ -1287,8 +1290,11 @@
         'src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc',
         'src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver.cc',
         'src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_posix.cc',
+        'src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_windows.cc',
         'src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.cc',
         'src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_fallback.cc',
+        'src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_posix.cc',
+        'src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_windows.cc',
         'src/core/ext/filters/client_channel/resolver/dns/native/dns_resolver.cc',
         'src/core/ext/filters/client_channel/resolver/sockaddr/sockaddr_resolver.cc',
         'src/core/ext/filters/client_channel/resolver/fake/fake_resolver.cc',

include/grpc/grpc.h

@@ -60,6 +60,8 @@ GRPCAPI void grpc_register_plugin(void (*init)(void), void (*destroy)(void));
 
 /** Initialize the grpc library.
 
+    After it's called, a matching invocation to grpc_shutdown() is expected.
+
     It is not safe to call any other grpc functions before calling this.
     (To avoid overhead, little checking is done, and some things may work. We
     do not warrant that they will continue to do so in future revisions of this
@@ -68,6 +70,9 @@ GRPCAPI void grpc_init(void);
 
 /** Shut down the grpc library.
 
+    Before it's called, there should haven been a matching invocation to
+    grpc_init().
+
     No memory is used by grpc after this call returns, nor are any instructions
     executing within the grpc library.
     Prior to calling, all application owned grpc objects must have been

include/grpc/impl/codegen/port_platform.h

@@ -420,12 +420,8 @@ typedef unsigned __int64 uint64_t;
 #define GPR_MAX_ALIGNMENT 16
 
 #ifndef GRPC_ARES
-#ifdef GPR_WINDOWS
-#define GRPC_ARES 0
-#else
 #define GRPC_ARES 1
 #endif
-#endif
 
 #ifndef GRPC_MUST_USE_RESULT
 #if defined(__GNUC__) && !defined(__MINGW32__)

package.xml

@@ -747,8 +747,11 @@
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver.cc" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_posix.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_windows.cc" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.cc" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_fallback.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_posix.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_windows.cc" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/resolver/dns/native/dns_resolver.cc" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/resolver/sockaddr/sockaddr_resolver.cc" role="src" />
     <file baseinstalldir="/" name="src/cpp/ext/filters/census/grpc_context.cc" role="src" />

requirements.bazel.txt

@@ -0,0 +1,10 @@
+# GRPC Python setup requirements
+coverage>=4.0
+cython==0.28.3
+enum34>=1.0.4
+protobuf>=3.5.0.post1
+six>=1.10
+wheel>=0.29
+futures>=2.2.0
+google-auth>=1.0.0
+oauth2client==4.1.0

src/core/ext/filters/client_channel/client_channel.cc

@@ -571,15 +571,32 @@ static void start_transport_op_locked(void* arg, grpc_error* error_ignored) {
 
   if (op->send_ping.on_initiate != nullptr || op->send_ping.on_ack != nullptr) {
     if (chand->lb_policy == nullptr) {
-      GRPC_CLOSURE_SCHED(
-          op->send_ping.on_initiate,
-          GRPC_ERROR_CREATE_FROM_STATIC_STRING("Ping with no load balancing"));
-      GRPC_CLOSURE_SCHED(
-          op->send_ping.on_ack,
-          GRPC_ERROR_CREATE_FROM_STATIC_STRING("Ping with no load balancing"));
+      grpc_error* error =
+          GRPC_ERROR_CREATE_FROM_STATIC_STRING("Ping with no load balancing");
+      GRPC_CLOSURE_SCHED(op->send_ping.on_initiate, GRPC_ERROR_REF(error));
+      GRPC_CLOSURE_SCHED(op->send_ping.on_ack, error);
     } else {
-      chand->lb_policy->PingOneLocked(op->send_ping.on_initiate,
-                                      op->send_ping.on_ack);
+      grpc_error* error = GRPC_ERROR_NONE;
+      grpc_core::LoadBalancingPolicy::PickState pick_state;
+      pick_state.initial_metadata = nullptr;
+      pick_state.initial_metadata_flags = 0;
+      pick_state.on_complete = nullptr;
+      memset(&pick_state.subchannel_call_context, 0,
+             sizeof(pick_state.subchannel_call_context));
+      pick_state.user_data = nullptr;
+      // Pick must return synchronously, because pick_state.on_complete is null.
+      GPR_ASSERT(chand->lb_policy->PickLocked(&pick_state, &error));
+      if (pick_state.connected_subchannel != nullptr) {
+        pick_state.connected_subchannel->Ping(op->send_ping.on_initiate,
+                                              op->send_ping.on_ack);
+      } else {
+        if (error == GRPC_ERROR_NONE) {
+          error = GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+              "LB policy dropped call on ping");
+        }
+        GRPC_CLOSURE_SCHED(op->send_ping.on_initiate, GRPC_ERROR_REF(error));
+        GRPC_CLOSURE_SCHED(op->send_ping.on_ack, error);
+      }
       op->bind_pollset = nullptr;
     }
     op->send_ping.on_initiate = nullptr;
@@ -2698,14 +2715,15 @@ class LbPicker {
                       grpc_combiner_scheduler(chand->combiner));
     calld->pick.on_complete = &calld->pick_closure;
     GRPC_CALL_STACK_REF(calld->owning_call, "pick_callback");
-    const bool pick_done = chand->lb_policy->PickLocked(&calld->pick);
+    grpc_error* error = GRPC_ERROR_NONE;
+    const bool pick_done = chand->lb_policy->PickLocked(&calld->pick, &error);
     if (GPR_LIKELY(pick_done)) {
       // Pick completed synchronously.
       if (grpc_client_channel_trace.enabled()) {
         gpr_log(GPR_INFO, "chand=%p calld=%p: pick completed synchronously",
                 chand, calld);
       }
-      pick_done_locked(elem, GRPC_ERROR_NONE);
+      pick_done_locked(elem, error);
       GRPC_CALL_STACK_UNREF(calld->owning_call, "pick_callback");
     } else {
       // Pick will be returned asynchronously.

src/core/ext/filters/client_channel/lb_policy.h

@@ -71,6 +71,7 @@ class LoadBalancingPolicy
     /// Storage for LB token in \a initial_metadata, or nullptr if not used.
     grpc_linked_mdelem lb_token_mdelem_storage;
     /// Closure to run when pick is complete, if not completed synchronously.
+    /// If null, pick will fail if a result is not available synchronously.
     grpc_closure* on_complete;
     /// Will be set to the selected subchannel, or nullptr on failure or when
     /// the LB policy decides to drop the call.
@@ -99,10 +100,15 @@ class LoadBalancingPolicy
   /// Finds an appropriate subchannel for a call, based on data in \a pick.
   /// \a pick must remain alive until the pick is complete.
   ///
-  /// If the pick succeeds and a result is known immediately, returns true.
-  /// Otherwise, \a pick->on_complete will be invoked once the pick is
-  /// complete with its error argument set to indicate success or failure.
-  virtual bool PickLocked(PickState* pick) GRPC_ABSTRACT;
+  /// If a result is known immediately, returns true, setting \a *error
+  /// upon failure.  Otherwise, \a pick->on_complete will be invoked once
+  /// the pick is complete with its error argument set to indicate success
+  /// or failure.
+  ///
+  /// If \a pick->on_complete is null and no result is known immediately,
+  /// a synchronous failure will be returned (i.e., \a *error will be
+  /// set and true will be returned).
+  virtual bool PickLocked(PickState* pick, grpc_error** error) GRPC_ABSTRACT;
 
   /// Cancels \a pick.
   /// The \a on_complete callback of the pending pick will be invoked with
@@ -133,12 +139,6 @@ class LoadBalancingPolicy
   virtual void HandOffPendingPicksLocked(LoadBalancingPolicy* new_policy)
       GRPC_ABSTRACT;
 
-  /// Performs a connected subchannel ping via \a ConnectedSubchannel::Ping()
-  /// against one of the connected subchannels managed by the policy.
-  /// Note: This is intended only for use in tests.
-  virtual void PingOneLocked(grpc_closure* on_initiate,
-                             grpc_closure* on_ack) GRPC_ABSTRACT;
-
   /// Tries to enter a READY connectivity state.
   /// TODO(roth): As part of restructuring how we handle IDLE state,
   /// consider whether this method is still needed.

src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.cc

@@ -123,7 +123,7 @@ class GrpcLb : public LoadBalancingPolicy {
   GrpcLb(const grpc_lb_addresses* addresses, const Args& args);
 
   void UpdateLocked(const grpc_channel_args& args) override;
-  bool PickLocked(PickState* pick) override;
+  bool PickLocked(PickState* pick, grpc_error** error) override;
   void CancelPickLocked(PickState* pick, grpc_error* error) override;
   void CancelMatchingPicksLocked(uint32_t initial_metadata_flags_mask,
                                  uint32_t initial_metadata_flags_eq,
@@ -133,7 +133,6 @@ class GrpcLb : public LoadBalancingPolicy {
   grpc_connectivity_state CheckConnectivityLocked(
       grpc_error** connectivity_error) override;
   void HandOffPendingPicksLocked(LoadBalancingPolicy* new_policy) override;
-  void PingOneLocked(grpc_closure* on_initiate, grpc_closure* on_ack) override;
   void ExitIdleLocked() override;
   void FillChildRefsForChannelz(ChildRefsList* child_subchannels,
                                 ChildRefsList* child_channels) override;
@@ -167,13 +166,6 @@ class GrpcLb : public LoadBalancingPolicy {
     PendingPick* next = nullptr;
   };
 
-  /// A linked list of pending pings waiting for the RR policy to be created.
-  struct PendingPing {
-    grpc_closure* on_initiate;
-    grpc_closure* on_ack;
-    PendingPing* next = nullptr;
-  };
-
   /// Contains a call to the LB server and all the data related to the call.
   class BalancerCallState
       : public InternallyRefCountedWithTracing<BalancerCallState> {
@@ -272,14 +264,12 @@ class GrpcLb : public LoadBalancingPolicy {
   void AddPendingPick(PendingPick* pp);
   static void OnPendingPickComplete(void* arg, grpc_error* error);
 
-  // Pending ping methods.
-  void AddPendingPing(grpc_closure* on_initiate, grpc_closure* on_ack);
-
   // Methods for dealing with the RR policy.
   void CreateOrUpdateRoundRobinPolicyLocked();
   grpc_channel_args* CreateRoundRobinPolicyArgsLocked();
   void CreateRoundRobinPolicyLocked(const Args& args);
-  bool PickFromRoundRobinPolicyLocked(bool force_async, PendingPick* pp);
+  bool PickFromRoundRobinPolicyLocked(bool force_async, PendingPick* pp,
+                                      grpc_error** error);
   void UpdateConnectivityStateFromRoundRobinPolicyLocked(
       grpc_error* rr_state_error);
   static void OnRoundRobinConnectivityChangedLocked(void* arg,
@@ -342,9 +332,8 @@ class GrpcLb : public LoadBalancingPolicy {
   grpc_timer lb_fallback_timer_;
   grpc_closure lb_on_fallback_;
 
-  // Pending picks and pings that are waiting on the RR policy's connectivity.
+  // Pending picks that are waiting on the RR policy's connectivity.
   PendingPick* pending_picks_ = nullptr;
-  PendingPing* pending_pings_ = nullptr;
 
   // The RR policy to use for the backends.
   OrphanablePtr<LoadBalancingPolicy> rr_policy_;
@@ -1080,7 +1069,6 @@ GrpcLb::GrpcLb(const grpc_lb_addresses* addresses,
 
 GrpcLb::~GrpcLb() {
   GPR_ASSERT(pending_picks_ == nullptr);
-  GPR_ASSERT(pending_pings_ == nullptr);
   gpr_mu_destroy(&lb_channel_mu_);
   gpr_free((void*)server_name_);
   grpc_channel_args_destroy(args_);
@@ -1126,14 +1114,6 @@ void GrpcLb::ShutdownLocked() {
     // Note: pp is deleted in this callback.
     GRPC_CLOSURE_SCHED(&pp->on_complete, GRPC_ERROR_REF(error));
   }
-  // Clear pending pings.
-  PendingPing* pping;
-  while ((pping = pending_pings_) != nullptr) {
-    pending_pings_ = pping->next;
-    GRPC_CLOSURE_SCHED(pping->on_initiate, GRPC_ERROR_REF(error));
-    GRPC_CLOSURE_SCHED(pping->on_ack, GRPC_ERROR_REF(error));
-    Delete(pping);
-  }
   GRPC_ERROR_UNREF(error);
 }
 
@@ -1147,9 +1127,10 @@ void GrpcLb::HandOffPendingPicksLocked(LoadBalancingPolicy* new_policy) {
     pending_picks_ = pp->next;
     pp->pick->on_complete = pp->original_on_complete;
     pp->pick->user_data = nullptr;
-    if (new_policy->PickLocked(pp->pick)) {
+    grpc_error* error = GRPC_ERROR_NONE;
+    if (new_policy->PickLocked(pp->pick, &error)) {
       // Synchronous return; schedule closure.
-      GRPC_CLOSURE_SCHED(pp->pick->on_complete, GRPC_ERROR_NONE);
+      GRPC_CLOSURE_SCHED(pp->pick->on_complete, error);
     }
     Delete(pp);
   }
@@ -1233,58 +1214,37 @@ void GrpcLb::ExitIdleLocked() {
   }
 }
 
-bool GrpcLb::PickLocked(PickState* pick) {
+bool GrpcLb::PickLocked(PickState* pick, grpc_error** error) {
   PendingPick* pp = PendingPickCreate(pick);
   bool pick_done = false;
   if (rr_policy_ != nullptr) {
-    const grpc_connectivity_state rr_connectivity_state =
-        rr_policy_->CheckConnectivityLocked(nullptr);
-    // The RR policy may have transitioned to SHUTDOWN but the callback
-    // registered to capture this event (on_rr_connectivity_changed_) may not
-    // have been invoked yet. We need to make sure we aren't trying to pick
-    // from an RR policy instance that's in shutdown.
-    if (rr_connectivity_state == GRPC_CHANNEL_SHUTDOWN) {
+    if (grpc_lb_glb_trace.enabled()) {
+      gpr_log(GPR_INFO, "[grpclb %p] about to PICK from RR %p", this,
+              rr_policy_.get());
+    }
+    pick_done =
+        PickFromRoundRobinPolicyLocked(false /* force_async */, pp, error);
+  } else {  // rr_policy_ == NULL
+    if (pick->on_complete == nullptr) {
+      *error = GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+          "No pick result available but synchronous result required.");
+      pick_done = true;
+    } else {
       if (grpc_lb_glb_trace.enabled()) {
         gpr_log(GPR_INFO,
-                "[grpclb %p] NOT picking from from RR %p: RR conn state=%s",
-                this, rr_policy_.get(),
-                grpc_connectivity_state_name(rr_connectivity_state));
+                "[grpclb %p] No RR policy. Adding to grpclb's pending picks",
+                this);
       }
       AddPendingPick(pp);
-      pick_done = false;
-    } else {  // RR not in shutdown
-      if (grpc_lb_glb_trace.enabled()) {
-        gpr_log(GPR_INFO, "[grpclb %p] about to PICK from RR %p", this,
-                rr_policy_.get());
+      if (!started_picking_) {
+        StartPickingLocked();
       }
-      pick_done = PickFromRoundRobinPolicyLocked(false /* force_async */, pp);
-    }
-  } else {  // rr_policy_ == NULL
-    if (grpc_lb_glb_trace.enabled()) {
-      gpr_log(GPR_INFO,
-              "[grpclb %p] No RR policy. Adding to grpclb's pending picks",
-              this);
-    }
-    AddPendingPick(pp);
-    if (!started_picking_) {
-      StartPickingLocked();
+      pick_done = false;
     }
-    pick_done = false;
   }
   return pick_done;
 }
 
-void GrpcLb::PingOneLocked(grpc_closure* on_initiate, grpc_closure* on_ack) {
-  if (rr_policy_ != nullptr) {
-    rr_policy_->PingOneLocked(on_initiate, on_ack);
-  } else {
-    AddPendingPing(on_initiate, on_ack);
-    if (!started_picking_) {
-      StartPickingLocked();
-    }
-  }
-}
-
 void GrpcLb::FillChildRefsForChannelz(ChildRefsList* child_subchannels,
                                       ChildRefsList* child_channels) {
   // delegate to the RoundRobin to fill the children subchannels.
@@ -1598,18 +1558,6 @@ void GrpcLb::AddPendingPick(PendingPick* pp) {
   pending_picks_ = pp;
 }
 
-//
-// PendingPing
-//
-
-void GrpcLb::AddPendingPing(grpc_closure* on_initiate, grpc_closure* on_ack) {
-  PendingPing* pping = New<PendingPing>();
-  pping->on_initiate = on_initiate;
-  pping->on_ack = on_ack;
-  pping->next = pending_pings_;
-  pending_pings_ = pping;
-}
-
 //
 // code for interacting with the RR policy
 //
@@ -1619,7 +1567,8 @@ void GrpcLb::AddPendingPing(grpc_closure* on_initiate, grpc_closure* on_ack) {
 // cleanups this callback would otherwise be responsible for.
 // If \a force_async is true, then we will manually schedule the
 // completion callback even if the pick is available immediately.
-bool GrpcLb::PickFromRoundRobinPolicyLocked(bool force_async, PendingPick* pp) {
+bool GrpcLb::PickFromRoundRobinPolicyLocked(bool force_async, PendingPick* pp,
+                                            grpc_error** error) {
   // Check for drops if we are not using fallback backend addresses.
   if (serverlist_ != nullptr) {
     // Look at the index into the serverlist to see if we should drop this call.
@@ -1653,11 +1602,12 @@ bool GrpcLb::PickFromRoundRobinPolicyLocked(bool force_async, PendingPick* pp) {
   GPR_ASSERT(pp->pick->user_data == nullptr);
   pp->pick->user_data = (void**)&pp->lb_token;
   // Pick via the RR policy.
-  bool pick_done = rr_policy_->PickLocked(pp->pick);
+  bool pick_done = rr_policy_->PickLocked(pp->pick, error);
   if (pick_done) {
     PendingPickSetMetadataAndContext(pp);
     if (force_async) {
-      GRPC_CLOSURE_SCHED(pp->original_on_complete, GRPC_ERROR_NONE);
+      GRPC_CLOSURE_SCHED(pp->original_on_complete, *error);
+      *error = GRPC_ERROR_NONE;
       pick_done = false;
     }
     Delete(pp);
@@ -1709,18 +1659,8 @@ void GrpcLb::CreateRoundRobinPolicyLocked(const Args& args) {
               "[grpclb %p] Pending pick about to (async) PICK from RR %p", this,
               rr_policy_.get());
     }
-    PickFromRoundRobinPolicyLocked(true /* force_async */, pp);
-  }
-  // Send pending pings to RR policy.
-  PendingPing* pping;
-  while ((pping = pending_pings_)) {
-    pending_pings_ = pping->next;
-    if (grpc_lb_glb_trace.enabled()) {
-      gpr_log(GPR_INFO, "[grpclb %p] Pending ping about to PING from RR %p",
-              this, rr_policy_.get());
-    }
-    rr_policy_->PingOneLocked(pping->on_initiate, pping->on_ack);
-    Delete(pping);
+    grpc_error* error = GRPC_ERROR_NONE;
+    PickFromRoundRobinPolicyLocked(true /* force_async */, pp, &error);
   }
 }
 

src/core/ext/filters/client_channel/lb_policy/pick_first/pick_first.cc

@@ -46,7 +46,7 @@ class PickFirst : public LoadBalancingPolicy {
   explicit PickFirst(const Args& args);
 
   void UpdateLocked(const grpc_channel_args& args) override;
-  bool PickLocked(PickState* pick) override;
+  bool PickLocked(PickState* pick, grpc_error** error) override;
   void CancelPickLocked(PickState* pick, grpc_error* error) override;
   void CancelMatchingPicksLocked(uint32_t initial_metadata_flags_mask,
                                  uint32_t initial_metadata_flags_eq,
@@ -56,7 +56,6 @@ class PickFirst : public LoadBalancingPolicy {
   grpc_connectivity_state CheckConnectivityLocked(
       grpc_error** connectivity_error) override;
   void HandOffPendingPicksLocked(LoadBalancingPolicy* new_policy) override;
-  void PingOneLocked(grpc_closure* on_initiate, grpc_closure* on_ack) override;
   void ExitIdleLocked() override;
   void FillChildRefsForChannelz(ChildRefsList* child_subchannels,
                                 ChildRefsList* ignored) override;
@@ -173,9 +172,10 @@ void PickFirst::HandOffPendingPicksLocked(LoadBalancingPolicy* new_policy) {
   PickState* pick;
   while ((pick = pending_picks_) != nullptr) {
     pending_picks_ = pick->next;
-    if (new_policy->PickLocked(pick)) {
+    grpc_error* error = GRPC_ERROR_NONE;
+    if (new_policy->PickLocked(pick, &error)) {
       // Synchronous return, schedule closure.
-      GRPC_CLOSURE_SCHED(pick->on_complete, GRPC_ERROR_NONE);
+      GRPC_CLOSURE_SCHED(pick->on_complete, error);
     }
   }
 }
@@ -259,13 +259,18 @@ void PickFirst::ExitIdleLocked() {
   }
 }
 
-bool PickFirst::PickLocked(PickState* pick) {
+bool PickFirst::PickLocked(PickState* pick, grpc_error** error) {
   // If we have a selected subchannel already, return synchronously.
   if (selected_ != nullptr) {
     pick->connected_subchannel = selected_->connected_subchannel()->Ref();
     return true;
   }
   // No subchannel selected yet, so handle asynchronously.
+  if (pick->on_complete == nullptr) {
+    *error = GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+        "No pick result available but synchronous result required.");
+    return true;
+  }
   if (!started_picking_) {
     StartPickingLocked();
   }
@@ -293,17 +298,6 @@ void PickFirst::NotifyOnStateChangeLocked(grpc_connectivity_state* current,
                                                  notify);
 }
 
-void PickFirst::PingOneLocked(grpc_closure* on_initiate, grpc_closure* on_ack) {
-  if (selected_ != nullptr) {
-    selected_->connected_subchannel()->Ping(on_initiate, on_ack);
-  } else {
-    GRPC_CLOSURE_SCHED(on_initiate,
-                       GRPC_ERROR_CREATE_FROM_STATIC_STRING("Not connected"));
-    GRPC_CLOSURE_SCHED(on_ack,
-                       GRPC_ERROR_CREATE_FROM_STATIC_STRING("Not connected"));
-  }
-}
-
 void PickFirst::FillChildRefsForChannelz(
     ChildRefsList* child_subchannels_to_fill, ChildRefsList* ignored) {
   mu_guard guard(&child_refs_mu_);

src/core/ext/filters/client_channel/lb_policy/round_robin/round_robin.cc

@@ -57,7 +57,7 @@ class RoundRobin : public LoadBalancingPolicy {
   explicit RoundRobin(const Args& args);
 
   void UpdateLocked(const grpc_channel_args& args) override;
-  bool PickLocked(PickState* pick) override;
+  bool PickLocked(PickState* pick, grpc_error** error) override;
   void CancelPickLocked(PickState* pick, grpc_error* error) override;
   void CancelMatchingPicksLocked(uint32_t initial_metadata_flags_mask,
                                  uint32_t initial_metadata_flags_eq,
@@ -67,7 +67,6 @@ class RoundRobin : public LoadBalancingPolicy {
   grpc_connectivity_state CheckConnectivityLocked(
       grpc_error** connectivity_error) override;
   void HandOffPendingPicksLocked(LoadBalancingPolicy* new_policy) override;
-  void PingOneLocked(grpc_closure* on_initiate, grpc_closure* on_ack) override;
   void ExitIdleLocked() override;
   void FillChildRefsForChannelz(ChildRefsList* child_subchannels,
                                 ChildRefsList* ignored) override;
@@ -253,9 +252,10 @@ void RoundRobin::HandOffPendingPicksLocked(LoadBalancingPolicy* new_policy) {
   PickState* pick;
   while ((pick = pending_picks_) != nullptr) {
     pending_picks_ = pick->next;
-    if (new_policy->PickLocked(pick)) {
+    grpc_error* error = GRPC_ERROR_NONE;
+    if (new_policy->PickLocked(pick, &error)) {
       // Synchronous return, schedule closure.
-      GRPC_CLOSURE_SCHED(pick->on_complete, GRPC_ERROR_NONE);
+      GRPC_CLOSURE_SCHED(pick->on_complete, error);
     }
   }
 }
@@ -368,7 +368,7 @@ void RoundRobin::DrainPendingPicksLocked() {
   }
 }
 
-bool RoundRobin::PickLocked(PickState* pick) {
+bool RoundRobin::PickLocked(PickState* pick, grpc_error** error) {
   if (grpc_lb_round_robin_trace.enabled()) {
     gpr_log(GPR_INFO, "[RR %p] Trying to pick (shutdown: %d)", this, shutdown_);
   }
@@ -376,6 +376,11 @@ bool RoundRobin::PickLocked(PickState* pick) {
   if (subchannel_list_ != nullptr) {
     if (DoPickLocked(pick)) return true;
   }
+  if (pick->on_complete == nullptr) {
+    *error = GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+        "No pick result available but synchronous result required.");
+    return true;
+  }
   /* no pick currently available. Save for later in list of pending picks */
   pick->next = pending_picks_;
   pending_picks_ = pick;
@@ -647,22 +652,6 @@ void RoundRobin::NotifyOnStateChangeLocked(grpc_connectivity_state* current,
                                                  notify);
 }
 
-void RoundRobin::PingOneLocked(grpc_closure* on_initiate,
-                               grpc_closure* on_ack) {
-  const size_t next_ready_index =
-      subchannel_list_->GetNextReadySubchannelIndexLocked();
-  if (next_ready_index < subchannel_list_->num_subchannels()) {
-    RoundRobinSubchannelData* selected =
-        subchannel_list_->subchannel(next_ready_index);
-    selected->connected_subchannel()->Ping(on_initiate, on_ack);
-  } else {
-    GRPC_CLOSURE_SCHED(on_initiate, GRPC_ERROR_CREATE_FROM_STATIC_STRING(
-                                        "Round Robin not connected"));
-    GRPC_CLOSURE_SCHED(on_ack, GRPC_ERROR_CREATE_FROM_STATIC_STRING(
-                                   "Round Robin not connected"));
-  }
-}
-
 void RoundRobin::UpdateLocked(const grpc_channel_args& args) {
   const grpc_arg* arg = grpc_channel_args_find(&args, GRPC_ARG_LB_ADDRESSES);
   AutoChildRefsUpdater guard(this);

src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc

@@ -23,7 +23,6 @@
 #include <limits.h>
 #include <stdio.h>
 #include <string.h>
-#include <unistd.h>
 
 #include <grpc/support/alloc.h>
 #include <grpc/support/string_util.h>
@@ -142,8 +141,8 @@ AresDnsResolver::AresDnsResolver(const ResolverArgs& args)
   channel_args_ = grpc_channel_args_copy(args.args);
   const grpc_arg* arg = grpc_channel_args_find(
       channel_args_, GRPC_ARG_SERVICE_CONFIG_DISABLE_RESOLUTION);
-  request_service_config_ = !grpc_channel_arg_get_integer(
-      arg, (grpc_integer_options){false, false, true});
+  grpc_integer_options integer_options = {false, false, true};
+  request_service_config_ = !grpc_channel_arg_get_integer(arg, integer_options);
   arg = grpc_channel_args_find(channel_args_,
                                GRPC_ARG_DNS_MIN_TIME_BETWEEN_RESOLUTIONS_MS);
   min_time_between_resolutions_ =

src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver.cc

@@ -18,11 +18,10 @@
 #include <grpc/support/port_platform.h>
 
 #include "src/core/lib/iomgr/port.h"
-#if GRPC_ARES == 1 && defined(GRPC_POSIX_SOCKET_ARES_EV_DRIVER)
+#if GRPC_ARES == 1 && !defined(GRPC_UV)
 
 #include <ares.h>
 #include <string.h>
-#include <sys/ioctl.h>
 
 #include "src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver.h"
 
@@ -32,7 +31,6 @@
 #include <grpc/support/time.h>
 #include "src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.h"
 #include "src/core/lib/gpr/string.h"
-#include "src/core/lib/iomgr/ev_posix.h"
 #include "src/core/lib/iomgr/iomgr_internal.h"
 #include "src/core/lib/iomgr/sockaddr_utils.h"
 
@@ -314,4 +312,4 @@ void grpc_ares_ev_driver_start_locked(grpc_ares_ev_driver* ev_driver) {
   }
 }
 
-#endif /* GRPC_ARES == 1 && defined(GRPC_POSIX_SOCKET_ARES_EV_DRIVER) */
+#endif /* GRPC_ARES == 1 && !defined(GRPC_UV) */

src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_windows.cc

@@ -0,0 +1,59 @@
+/*
+ *
+ * Copyright 2016 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+#include <grpc/support/port_platform.h>
+
+#include "src/core/lib/iomgr/port.h"
+#if GRPC_ARES == 1 && defined(GPR_WINDOWS)
+
+#include <ares.h>
+#include <string.h>
+#include "src/core/lib/gprpp/memory.h"
+
+#include "src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver.h"
+
+namespace grpc_core {
+
+/* TODO: fill in the body of GrpcPolledFdWindows to enable c-ares on Windows.
+   This dummy implementation only allows grpc to compile on windows with
+   GRPC_ARES=1. */
+class GrpcPolledFdWindows : public GrpcPolledFd {
+ public:
+  GrpcPolledFdWindows() { abort(); }
+  ~GrpcPolledFdWindows() { abort(); }
+  void RegisterForOnReadableLocked(grpc_closure* read_closure) override {
+    abort();
+  }
+  void RegisterForOnWriteableLocked(grpc_closure* write_closure) override {
+    abort();
+  }
+  bool IsFdStillReadableLocked() override { abort(); }
+  void ShutdownLocked(grpc_error* error) override { abort(); }
+  ares_socket_t GetWrappedAresSocketLocked() override { abort(); }
+  const char* GetName() override { abort(); }
+};
+
+GrpcPolledFd* NewGrpcPolledFdLocked(ares_socket_t as,
+                                    grpc_pollset_set* driver_pollset_set) {
+  return nullptr;
+}
+
+void ConfigureAresChannelLocked(ares_channel* channel) { abort(); }
+
+}  // namespace grpc_core
+
+#endif /* GRPC_ARES == 1 && defined(GPR_WINDOWS) */

src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.cc

@@ -22,7 +22,6 @@
 
 #include "src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.h"
 #include "src/core/lib/iomgr/sockaddr.h"
-#include "src/core/lib/iomgr/socket_utils_posix.h"
 
 #include <string.h>
 #include <sys/types.h>
@@ -215,7 +214,7 @@ static void on_hostbyname_done_locked(void* arg, int status, int timeouts,
           memset(&addr, 0, addr_len);
           memcpy(&addr.sin6_addr, hostent->h_addr_list[i - prev_naddr],
                  sizeof(struct in6_addr));
-          addr.sin6_family = static_cast<sa_family_t>(hostent->h_addrtype);
+          addr.sin6_family = static_cast<unsigned char>(hostent->h_addrtype);
           addr.sin6_port = hr->port;
           grpc_lb_addresses_set_address(
               *lb_addresses, i, &addr, addr_len,
@@ -236,7 +235,7 @@ static void on_hostbyname_done_locked(void* arg, int status, int timeouts,
           memset(&addr, 0, addr_len);
           memcpy(&addr.sin_addr, hostent->h_addr_list[i - prev_naddr],
                  sizeof(struct in_addr));
-          addr.sin_family = static_cast<sa_family_t>(hostent->h_addrtype);
+          addr.sin_family = static_cast<unsigned char>(hostent->h_addrtype);
           addr.sin_port = hr->port;
           grpc_lb_addresses_set_address(
               *lb_addresses, i, &addr, addr_len,
@@ -281,7 +280,7 @@ static void on_srv_query_done_locked(void* arg, int status, int timeouts,
           grpc_ares_ev_driver_get_channel_locked(r->ev_driver);
       for (struct ares_srv_reply* srv_it = reply; srv_it != nullptr;
            srv_it = srv_it->next) {
-        if (grpc_ipv6_loopback_available()) {
+        if (grpc_ares_query_ipv6()) {
           grpc_ares_hostbyname_request* hr = create_hostbyname_request_locked(
               r, srv_it->host, htons(srv_it->port), true /* is_balancer */);
           ares_gethostbyname(*channel, hr->host, AF_INET6,
@@ -452,7 +451,7 @@ static grpc_ares_request* grpc_dns_lookup_ares_locked_impl(
     }
   }
   r->pending_queries = 1;
-  if (grpc_ipv6_loopback_available()) {
+  if (grpc_ares_query_ipv6()) {
     hr = create_hostbyname_request_locked(r, host, strhtons(port),
                                           false /* is_balancer */);
     ares_gethostbyname(*channel, hr->host, AF_INET6, on_hostbyname_done_locked,

src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.h

@@ -70,6 +70,10 @@ void grpc_ares_cleanup(void);
  * and destroys the grpc_ares_request */
 void grpc_ares_complete_request_locked(grpc_ares_request* request);
 
+/* Indicates whether or not AAAA queries should be attempted. */
+/* E.g., return false if ipv6 is known to not be available. */
+bool grpc_ares_query_ipv6();
+
 /* Exposed only for testing */
 void grpc_cares_wrapper_test_only_address_sorting_sort(
     grpc_lb_addresses* lb_addrs);

src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_posix.cc

@@ -0,0 +1,29 @@
+/*
+ *
+ * Copyright 2016 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#include <grpc/support/port_platform.h>
+
+#include "src/core/lib/iomgr/port.h"
+#if GRPC_ARES == 1 && defined(GRPC_POSIX_SOCKET_ARES_EV_DRIVER)
+
+#include "src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.h"
+#include "src/core/lib/iomgr/socket_utils_posix.h"
+
+bool grpc_ares_query_ipv6() { return grpc_ipv6_loopback_available(); }
+
+#endif /* GRPC_ARES == 1 && defined(GRPC_POSIX_SOCKET_ARES_EV_DRIVER) */

src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper_windows.cc

@@ -0,0 +1,29 @@
+/*
+ *
+ * Copyright 2016 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#include <grpc/support/port_platform.h>
+
+#include "src/core/lib/iomgr/port.h"
+#if GRPC_ARES == 1 && defined(GPR_WINDOWS)
+
+#include "src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.h"
+#include "src/core/lib/iomgr/socket_windows.h"
+
+bool grpc_ares_query_ipv6() { return grpc_ipv6_loopback_available(); }
+
+#endif /* GRPC_ARES == 1 && defined(GPR_WINDOWS) */

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

@@ -1208,7 +1208,7 @@ void grpc_chttp2_complete_closure_step(grpc_chttp2_transport* t,
         grpc_error_add_child(closure->error_data.error, error);
   }
   if (closure->next_data.scratch < CLOSURE_BARRIER_FIRST_REF_BIT) {
-    if ((t->write_state == GRPC_CHTTP2_WRITE_STATE_IDLE) ||
+    if (s->seen_error || (t->write_state == GRPC_CHTTP2_WRITE_STATE_IDLE) ||
         !(closure->next_data.scratch & CLOSURE_BARRIER_MAY_COVER_WRITE)) {
       GRPC_CLOSURE_RUN(closure, closure->error_data.error);
     } else {

src/core/lib/iomgr/ev_epoll1_linux.cc

@@ -1203,6 +1203,9 @@ static const grpc_event_engine_vtable vtable = {
     fd_notify_on_read,
     fd_notify_on_write,
     fd_notify_on_error,
+    fd_become_readable,
+    fd_become_writable,
+    fd_has_errors,
     fd_is_shutdown,
 
     pollset_init,

src/core/lib/iomgr/ev_epollex_linux.cc

@@ -1615,6 +1615,9 @@ static const grpc_event_engine_vtable vtable = {
     fd_notify_on_read,
     fd_notify_on_write,
     fd_notify_on_error,
+    fd_become_readable,
+    fd_become_writable,
+    fd_has_errors,
     fd_is_shutdown,
 
     pollset_init,

src/core/lib/iomgr/ev_epollsig_linux.cc

@@ -948,6 +948,12 @@ static void fd_notify_on_error(grpc_fd* fd, grpc_closure* closure) {
   fd->error_closure->NotifyOn(closure);
 }
 
+static void fd_become_readable(grpc_fd* fd) { fd->read_closure->SetReady(); }
+
+static void fd_become_writable(grpc_fd* fd) { fd->write_closure->SetReady(); }
+
+static void fd_has_errors(grpc_fd* fd) { fd->error_closure->SetReady(); }
+
 /*******************************************************************************
  * Pollset Definitions
  */
@@ -1105,12 +1111,6 @@ static int poll_deadline_to_millis_timeout(grpc_millis millis) {
     return static_cast<int>(delta);
 }
 
-static void fd_become_readable(grpc_fd* fd) { fd->read_closure->SetReady(); }
-
-static void fd_become_writable(grpc_fd* fd) { fd->write_closure->SetReady(); }
-
-static void fd_has_errors(grpc_fd* fd) { fd->error_closure->SetReady(); }
-
 static void pollset_release_polling_island(grpc_pollset* ps,
                                            const char* reason) {
   if (ps->po.pi != nullptr) {
@@ -1647,6 +1647,9 @@ static const grpc_event_engine_vtable vtable = {
     fd_notify_on_read,
     fd_notify_on_write,
     fd_notify_on_error,
+    fd_become_readable,
+    fd_become_writable,
+    fd_has_errors,
     fd_is_shutdown,
 
     pollset_init,

src/core/lib/iomgr/ev_poll_posix.cc

@@ -538,6 +538,24 @@ static void fd_notify_on_error(grpc_fd* fd, grpc_closure* closure) {
   GRPC_CLOSURE_SCHED(closure, GRPC_ERROR_CANCELLED);
 }
 
+static void fd_set_readable(grpc_fd* fd) {
+  gpr_mu_lock(&fd->mu);
+  set_ready_locked(fd, &fd->read_closure);
+  gpr_mu_unlock(&fd->mu);
+}
+
+static void fd_set_writable(grpc_fd* fd) {
+  gpr_mu_lock(&fd->mu);
+  set_ready_locked(fd, &fd->write_closure);
+  gpr_mu_unlock(&fd->mu);
+}
+
+static void fd_set_error(grpc_fd* fd) {
+  if (grpc_polling_trace.enabled()) {
+    gpr_log(GPR_ERROR, "Polling engine does not support tracking errors.");
+  }
+}
+
 static uint32_t fd_begin_poll(grpc_fd* fd, grpc_pollset* pollset,
                               grpc_pollset_worker* worker, uint32_t read_mask,
                               uint32_t write_mask, grpc_fd_watcher* watcher) {
@@ -1700,6 +1718,9 @@ static const grpc_event_engine_vtable vtable = {
     fd_notify_on_read,
     fd_notify_on_write,
     fd_notify_on_error,
+    fd_set_readable,
+    fd_set_writable,
+    fd_set_error,
     fd_is_shutdown,
 
     pollset_init,

src/core/lib/iomgr/ev_posix.cc

@@ -239,6 +239,12 @@ void grpc_fd_notify_on_error(grpc_fd* fd, grpc_closure* closure) {
   g_event_engine->fd_notify_on_error(fd, closure);
 }
 
+void grpc_fd_set_readable(grpc_fd* fd) { g_event_engine->fd_set_readable(fd); }
+
+void grpc_fd_set_writable(grpc_fd* fd) { g_event_engine->fd_set_writable(fd); }
+
+void grpc_fd_set_error(grpc_fd* fd) { g_event_engine->fd_set_error(fd); }
+
 static size_t pollset_size(void) { return g_event_engine->pollset_size; }
 
 static void pollset_init(grpc_pollset* pollset, gpr_mu** mu) {

src/core/lib/iomgr/ev_posix.h

@@ -51,6 +51,9 @@ typedef struct grpc_event_engine_vtable {
   void (*fd_notify_on_read)(grpc_fd* fd, grpc_closure* closure);
   void (*fd_notify_on_write)(grpc_fd* fd, grpc_closure* closure);
   void (*fd_notify_on_error)(grpc_fd* fd, grpc_closure* closure);
+  void (*fd_set_readable)(grpc_fd* fd);
+  void (*fd_set_writable)(grpc_fd* fd);
+  void (*fd_set_error)(grpc_fd* fd);
   bool (*fd_is_shutdown)(grpc_fd* fd);
 
   void (*pollset_init)(grpc_pollset* pollset, gpr_mu** mu);
@@ -141,6 +144,21 @@ void grpc_fd_notify_on_write(grpc_fd* fd, grpc_closure* closure);
  * needs to have been set on grpc_fd_create */
 void grpc_fd_notify_on_error(grpc_fd* fd, grpc_closure* closure);
 
+/* Forcibly set the fd to be readable, resulting in the closure registered with
+ * grpc_fd_notify_on_read being invoked.
+ */
+void grpc_fd_set_readable(grpc_fd* fd);
+
+/* Forcibly set the fd to be writable, resulting in the closure registered with
+ * grpc_fd_notify_on_write being invoked.
+ */
+void grpc_fd_set_writable(grpc_fd* fd);
+
+/* Forcibly set the fd to have errored, resulting in the closure registered with
+ * grpc_fd_notify_on_error being invoked.
+ */
+void grpc_fd_set_error(grpc_fd* fd);
+
 /* pollset_posix functions */
 
 /* Add an fd to a pollset */

src/core/lib/iomgr/socket_windows.cc

@@ -36,6 +36,7 @@
 #include "src/core/lib/iomgr/iomgr_internal.h"
 #include "src/core/lib/iomgr/pollset.h"
 #include "src/core/lib/iomgr/pollset_windows.h"
+#include "src/core/lib/iomgr/sockaddr_windows.h"
 #include "src/core/lib/iomgr/socket_windows.h"
 
 grpc_winsocket* grpc_winsocket_create(SOCKET socket, const char* name) {
@@ -148,4 +149,32 @@ void grpc_socket_become_ready(grpc_winsocket* socket,
   if (should_destroy) destroy(socket);
 }
 
+static gpr_once g_probe_ipv6_once = GPR_ONCE_INIT;
+static bool g_ipv6_loopback_available = false;
+
+static void probe_ipv6_once(void) {
+  SOCKET s = socket(AF_INET6, SOCK_STREAM, 0);
+  g_ipv6_loopback_available = 0;
+  if (s == INVALID_SOCKET) {
+    gpr_log(GPR_INFO, "Disabling AF_INET6 sockets because socket() failed.");
+  } else {
+    grpc_sockaddr_in6 addr;
+    memset(&addr, 0, sizeof(addr));
+    addr.sin6_family = AF_INET6;
+    addr.sin6_addr.s6_addr[15] = 1; /* [::1]:0 */
+    if (bind(s, reinterpret_cast<grpc_sockaddr*>(&addr), sizeof(addr)) == 0) {
+      g_ipv6_loopback_available = 1;
+    } else {
+      gpr_log(GPR_INFO,
+              "Disabling AF_INET6 sockets because ::1 is not available.");
+    }
+    closesocket(s);
+  }
+}
+
+int grpc_ipv6_loopback_available(void) {
+  gpr_once_init(&g_probe_ipv6_once, probe_ipv6_once);
+  return g_ipv6_loopback_available;
+}
+
 #endif /* GRPC_WINSOCK_SOCKET */

src/core/lib/iomgr/socket_windows.h

@@ -108,6 +108,10 @@ void grpc_socket_notify_on_read(grpc_winsocket* winsocket,
 void grpc_socket_become_ready(grpc_winsocket* winsocket,
                               grpc_winsocket_callback_info* ci);
 
+/* Returns true if this system can create AF_INET6 sockets bound to ::1.
+   The value is probed once, and cached for the life of the process. */
+int grpc_ipv6_loopback_available(void);
+
 #endif
 
 #endif /* GRPC_CORE_LIB_IOMGR_SOCKET_WINDOWS_H */

src/core/lib/surface/call.cc

@@ -529,6 +529,7 @@ void grpc_call_internal_unref(grpc_call* c REF_ARG) {
 static void release_call(void* call, grpc_error* error) {
   grpc_call* c = static_cast<grpc_call*>(call);
   grpc_channel* channel = c->channel;
+  gpr_free(static_cast<void*>(const_cast<char*>(c->final_info.error_string)));
   grpc_call_combiner_destroy(&c->call_combiner);
   grpc_channel_update_call_size_estimate(channel, gpr_arena_destroy(c->arena));
   GRPC_CHANNEL_INTERNAL_UNREF(channel, "call");
@@ -573,7 +574,6 @@ static void destroy_call(void* call, grpc_error* error) {
   grpc_call_stack_destroy(CALL_STACK_FROM_CALL(c), &c->final_info,
                           GRPC_CLOSURE_INIT(&c->release_call, release_call, c,
                                             grpc_schedule_on_exec_ctx));
-  gpr_free(static_cast<void*>(const_cast<char*>(c->final_info.error_string)));
 }
 
 void grpc_call_ref(grpc_call* c) { gpr_ref(&c->ext_ref); }

src/csharp/README.md

@@ -32,6 +32,14 @@ HOW TO USE
 
 - To be able to generate code from Protocol Buffer (`.proto`) file definitions, add the [Grpc.Tools](https://www.nuget.org/packages/Grpc.Tools/) NuGet package that contains Protocol Buffers compiler (_protoc_) and the gRPC _protoc_ plugin.
 
+**Xamarin.Android and Xamarin.iOS (Experimental only)**
+
+See [Experimentally supported platforms](experimental) for instructions.
+
+**Unity (Experimental only)**
+
+See [Experimentally supported platforms](experimental) for instructions.
+
 BUILD FROM SOURCE
 -----------------
 

src/csharp/build_packages_dotnetcli.bat

@@ -21,18 +21,12 @@ set DOTNET=dotnet
 
 mkdir ..\..\artifacts
 
-@rem Collect the artifacts built by the previous build step if running on Jenkins
+@rem Collect the artifacts built by the previous build step
 mkdir nativelibs
-@rem Jenkins flow (deprecated)
-powershell -Command "cp -r ..\..\platform=*\artifacts\csharp_ext_* nativelibs"
-@rem Kokoro flow
 powershell -Command "cp -r ..\..\input_artifacts\csharp_ext_* nativelibs"
 
 @rem Collect protoc artifacts built by the previous build step
 mkdir protoc_plugins
-@rem Jenkins flow (deprecated)
-powershell -Command "cp -r ..\..\platform=*\artifacts\protoc_* protoc_plugins"
-@rem Kokoro flow
 powershell -Command "cp -r ..\..\input_artifacts\protoc_* protoc_plugins"
 
 %DOTNET% restore Grpc.sln || goto :error

src/csharp/build_packages_dotnetcli.sh

@@ -1,52 +0,0 @@
-#!/bin/bash
-# Copyright 2016 gRPC authors.
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-set -ex
-
-cd $(dirname $0)
-
-mkdir -p ../../artifacts/
-
-# Collect the artifacts built by the previous build step
-mkdir -p nativelibs
-# Jenkins flow (deprecated)
-cp -r $EXTERNAL_GIT_ROOT/platform={windows,linux,macos}/artifacts/csharp_ext_* nativelibs || true
-# Kokoro flow
-cp -r $EXTERNAL_GIT_ROOT/input_artifacts/csharp_ext_* nativelibs || true
-
-# Collect protoc artifacts built by the previous build step
-mkdir -p protoc_plugins
-# Jenkins flow (deprecated)
-cp -r $EXTERNAL_GIT_ROOT/platform={windows,linux,macos}/artifacts/protoc_* protoc_plugins || true
-# Kokoro flow
-cp -r $EXTERNAL_GIT_ROOT/input_artifacts/protoc_* protoc_plugins || true
-
-dotnet restore Grpc.sln
-
-# To be able to build, we also need to put grpc_csharp_ext to its normal location
-mkdir -p ../../libs/opt
-cp nativelibs/csharp_ext_linux_x64/libgrpc_csharp_ext.so ../../libs/opt
-
-dotnet pack --configuration Release Grpc.Core --output ../../../artifacts
-dotnet pack --configuration Release Grpc.Core.Testing --output ../../../artifacts
-dotnet pack --configuration Release Grpc.Auth --output ../../../artifacts
-dotnet pack --configuration Release Grpc.HealthCheck --output ../../../artifacts
-dotnet pack --configuration Release Grpc.Reflection --output ../../../artifacts
-
-nuget pack Grpc.nuspec -Version "1.15.0-dev" -OutputDirectory ../../artifacts
-nuget pack Grpc.Core.NativeDebug.nuspec -Version "1.15.0-dev" -OutputDirectory ../../artifacts
-nuget pack Grpc.Tools.nuspec -Version "1.15.0-dev" -OutputDirectory ../../artifacts
-
-(cd ../../artifacts && zip csharp_nugets_dotnetcli.zip *.nupkg)

src/csharp/build_unitypackage.bat

@@ -0,0 +1,78 @@
+@rem Copyright 2018 The gRPC Authors
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem     http://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+
+@rem Current package versions
+set VERSION=1.15.0-dev
+
+@rem Adjust the location of nuget.exe
+set NUGET=C:\nuget\nuget.exe
+set DOTNET=dotnet
+
+mkdir ..\..\artifacts
+
+@rem Collect the artifacts built by the previous build step
+mkdir nativelibs
+powershell -Command "cp -r ..\..\input_artifacts\csharp_ext_* nativelibs"
+
+@rem Collect protoc artifacts built by the previous build step
+mkdir protoc_plugins
+powershell -Command "cp -r ..\..\input_artifacts\protoc_* protoc_plugins"
+
+%DOTNET% restore Grpc.sln || goto :error
+
+@rem To be able to build, we also need to put grpc_csharp_ext to its normal location
+xcopy /Y /I nativelibs\csharp_ext_windows_x64\grpc_csharp_ext.dll ..\..\cmake\build\x64\Release\
+
+%DOTNET% build --configuration Release Grpc.Core || goto :error
+@rem build HealthCheck to get hold of Google.Protobuf.dll assembly
+%DOTNET% build --configuration Release Grpc.HealthCheck || goto :error
+
+@rem copy Grpc assemblies to the unity package skeleton
+@rem TODO(jtattermusch): Add Grpc.Auth assembly and its dependencies
+copy /Y Grpc.Core\bin\Release\net45\Grpc.Core.dll unitypackage\unitypackage_skeleton\Plugins\Grpc.Core\lib\net45\Grpc.Core.dll || goto :error
+copy /Y Grpc.Core\bin\Release\net45\Grpc.Core.pdb unitypackage\unitypackage_skeleton\Plugins\Grpc.Core\lib\net45\Grpc.Core.pdb || goto :error
+copy /Y Grpc.Core\bin\Release\net45\Grpc.Core.xml unitypackage\unitypackage_skeleton\Plugins\Grpc.Core\lib\net45\Grpc.Core.xml || goto :error
+
+@rem copy desktop native libraries to the unity package skeleton
+copy /Y nativelibs\csharp_ext_linux_x86\libgrpc_csharp_ext.so unitypackage\unitypackage_skeleton\Plugins\Grpc.Core\runtimes\linux\x86\libgrpc_csharp_ext.so || goto :error
+copy /Y nativelibs\csharp_ext_linux_x64\libgrpc_csharp_ext.so unitypackage\unitypackage_skeleton\Plugins\Grpc.Core\runtimes\linux\x64\libgrpc_csharp_ext.so || goto :error
+copy /Y nativelibs\csharp_ext_macos_x86\libgrpc_csharp_ext.dylib unitypackage\unitypackage_skeleton\Plugins\Grpc.Core\runtimes\osx\x86\grpc_csharp_ext.bundle || goto :error
+copy /Y nativelibs\csharp_ext_macos_x64\libgrpc_csharp_ext.dylib unitypackage\unitypackage_skeleton\Plugins\Grpc.Core\runtimes\osx\x64\grpc_csharp_ext.bundle || goto :error
+copy /Y nativelibs\csharp_ext_windows_x86\grpc_csharp_ext.dll unitypackage\unitypackage_skeleton\Plugins\Grpc.Core\runtimes\win\x86\grpc_csharp_ext.dll || goto :error
+copy /Y nativelibs\csharp_ext_windows_x64\grpc_csharp_ext.dll unitypackage\unitypackage_skeleton\Plugins\Grpc.Core\runtimes\win\x64\grpc_csharp_ext.dll || goto :error
+
+@rem add Android and iOS native libraries
+copy /Y nativelibs\csharp_ext_linux_android_armeabi-v7a\libgrpc_csharp_ext.so unitypackage\unitypackage_skeleton\Plugins\Grpc.Core\runtimes\android\armeabi-v7a\libgrpc_csharp_ext.so || goto :error
+copy /Y nativelibs\csharp_ext_linux_android_arm64-v8a\libgrpc_csharp_ext.so unitypackage\unitypackage_skeleton\Plugins\Grpc.Core\runtimes\android\arm64-v8a\libgrpc_csharp_ext.so || goto :error
+copy /Y nativelibs\csharp_ext_linux_android_x86\libgrpc_csharp_ext.so unitypackage\unitypackage_skeleton\Plugins\Grpc.Core\runtimes\android\x86\libgrpc_csharp_ext.so || goto :error
+copy /Y nativelibs\csharp_ext_macos_ios\libgrpc_csharp_ext.a unitypackage\unitypackage_skeleton\Plugins\Grpc.Core\runtimes\ios\libgrpc_csharp_ext.a || goto :error
+copy /Y nativelibs\csharp_ext_macos_ios\libgrpc.a unitypackage\unitypackage_skeleton\Plugins\Grpc.Core\runtimes\ios\libgrpc.a || goto :error
+
+@rem add gRPC dependencies
+@rem TODO(jtattermusch): also include XMLdoc
+copy /Y Grpc.Core\bin\Release\net45\System.Interactive.Async.dll unitypackage\unitypackage_skeleton\Plugins\System.Interactive.Async\lib\net45\System.Interactive.Async.dll || goto :error
+
+@rem add Google.Protobuf
+@rem TODO(jtattermusch): also include XMLdoc
+copy /Y Grpc.HealthCheck\bin\Release\net45\Google.Protobuf.dll unitypackage\unitypackage_skeleton\Plugins\Google.Protobuf\lib\net45\Google.Protobuf.dll || goto :error
+
+@rem create a zipfile that will act as a Unity package
+powershell -Command "Add-Type -Assembly 'System.IO.Compression.FileSystem'; [System.IO.Compression.ZipFile]::CreateFromDirectory('unitypackage\unitypackage_skeleton', 'grpc_unity_package.zip');"
+copy /Y grpc_unity_package.zip ..\..\artifacts\grpc_unity_package.%VERSION%.zip || goto :error
+
+goto :EOF
+
+:error
+echo Failed!
+exit /b %errorlevel%

src/csharp/experimental/README.md

@@ -1,16 +1,22 @@
 This directory contains useful resources for getting gRPC C# to work on
-not-yet-supported platforms.
+platforms that are not yet fully supported.
 
-# Unity & Xamarin
-gRPC C# currently doesn't support Unity or Xamarin, but some proof-of-concept
-work has been done. Some of the resources are shared in this directory to
-ease community work on Unity & Xamarin support.
+# Xamarin
 
-## Crosscompiling `grpc_csharp_ext` for Android
+gRPC C# now has experimental support for Xamarin.
+See [HelloworldXamarin](/examples/csharp/HelloworldXamarin) for an example how to use it.
 
-* Install [Android NDK](https://developer.android.com/ndk/index.html)
-* Run `./build_native_ext_for_android.sh` to crosscompile using cmake.
+What's currently supported:
 
-## Crosscompiling `grpc_csharp_ext` for iOS
+Xamarin.Android
+- supported API level: Kitkat 4.4+ (= API level 19)
+- supported ABIs: `armeabi-v7a` (vast majority of Android devices out there), 
+  `arm64-v8a` (some newer Android devices), `x86` (for emulator)
 
-TBD
+Xamarin.iOS
+- supported architectures: arm64 (iPhone 6+) and x86_64 (iPhone simulator)
+
+# Unity
+gRPC C# currently doesn't support Unity, but some proof-of-concept
+work has been done. There is in-progress effort to provide users
+with a pre-built gRPC package that can be used in their projects.

src/csharp/unitypackage/README.md

@@ -0,0 +1,13 @@
+# Scripts for building gRPC C# package for Unity
+
+Scripts in this directory are of no interest for end users. They are part
+of internal tooling to automate building of the gRPC C# package for Unity.
+
+- `unitypackage_skeleton` - preconfigured `.meta` files for the unity package
+  layout. The actual assemblies and native libraries will be added into
+  this hierarchy while building the package.
+  Note: The `.meta` file were created by the Unity IDE by manually adding the assemblies/native libraries
+  to a Unity project and configuring their target plaform/architecture in the UI (these setting get recorded in
+  `.meta` files). The `.meta` format is not very well documented and there seems to be no easy way to generate them
+  automatically.
+  

src/csharp/unitypackage/unitypackage_skeleton/Plugins/Google.Protobuf.meta

@@ -0,0 +1,8 @@
+fileFormatVersion: 2
+guid: 4b6ebd913ac610041b63fc847ee96302
+folderAsset: yes
+DefaultImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

src/csharp/unitypackage/unitypackage_skeleton/Plugins/Google.Protobuf/lib.meta

@@ -0,0 +1,8 @@
+fileFormatVersion: 2
+guid: e4ab5b3f8a676a84a9eb3ffcf1e8138d
+folderAsset: yes
+DefaultImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

src/csharp/unitypackage/unitypackage_skeleton/Plugins/Google.Protobuf/lib/net45.meta

@@ -0,0 +1,8 @@
+fileFormatVersion: 2
+guid: 4c50e24955a9a294b99ad097ae2e252a
+folderAsset: yes
+DefaultImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

src/csharp/unitypackage/unitypackage_skeleton/Plugins/Google.Protobuf/lib/net45/Google.Protobuf.dll.meta

@@ -0,0 +1,30 @@
+fileFormatVersion: 2
+guid: 286edf5aec6aae64697e5e8b7ab9b60e
+PluginImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  iconMap: {}
+  executionOrder: {}
+  isPreloaded: 0
+  isOverridable: 0
+  platformData:
+  - first:
+      Any: 
+    second:
+      enabled: 1
+      settings: {}
+  - first:
+      Editor: Editor
+    second:
+      enabled: 0
+      settings:
+        DefaultValueInitialized: true
+  - first:
+      Windows Store Apps: WindowsStoreApps
+    second:
+      enabled: 0
+      settings:
+        CPU: AnyCPU
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

src/csharp/unitypackage/unitypackage_skeleton/Plugins/Google.Protobuf/lib/net45/Google.Protobuf.xml.meta

@@ -0,0 +1,7 @@
+fileFormatVersion: 2
+guid: 22de11620a7e57e41bc221729937524c
+TextScriptImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

src/csharp/unitypackage/unitypackage_skeleton/Plugins/Grpc.Core.meta

@@ -0,0 +1,10 @@
+fileFormatVersion: 2
+guid: e28eaddc034fe664591e93e8816968aa
+folderAsset: yes
+timeCreated: 1531219385
+licenseType: Free
+DefaultImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

src/csharp/unitypackage/unitypackage_skeleton/Plugins/Grpc.Core/lib.meta

@@ -0,0 +1,10 @@
+fileFormatVersion: 2
+guid: 1f862d451f11a2442aeac99ad2827285
+folderAsset: yes
+timeCreated: 1531219385
+licenseType: Free
+DefaultImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

src/csharp/unitypackage/unitypackage_skeleton/Plugins/Grpc.Core/lib/net45.meta

@@ -0,0 +1,10 @@
+fileFormatVersion: 2
+guid: 89bdbe2a1282d4e40ba11e96b1481d09
+folderAsset: yes
+timeCreated: 1531219385
+licenseType: Free
+DefaultImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

src/csharp/unitypackage/unitypackage_skeleton/Plugins/Grpc.Core/lib/net45/Grpc.Core.dll.meta

@@ -0,0 +1,32 @@
+fileFormatVersion: 2
+guid: 63fdcd70d29d1dc49b4e61e22a9e96e1
+timeCreated: 1531219386
+licenseType: Free
+PluginImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  iconMap: {}
+  executionOrder: {}
+  isPreloaded: 0
+  isOverridable: 0
+  platformData:
+  - first:
+      Any: 
+    second:
+      enabled: 1
+      settings: {}
+  - first:
+      Editor: Editor
+    second:
+      enabled: 0
+      settings:
+        DefaultValueInitialized: true
+  - first:
+      Windows Store Apps: WindowsStoreApps
+    second:
+      enabled: 0
+      settings:
+        CPU: AnyCPU
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

src/csharp/unitypackage/unitypackage_skeleton/Plugins/Grpc.Core/lib/net45/Grpc.Core.pdb.meta

@@ -0,0 +1,9 @@
+fileFormatVersion: 2
+guid: 49a6ef383d4d43640b6c7fd8168415ae
+timeCreated: 1531219385
+licenseType: Free
+DefaultImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

src/csharp/unitypackage/unitypackage_skeleton/Plugins/Grpc.Core/lib/net45/Grpc.Core.xml.meta

@@ -0,0 +1,9 @@
+fileFormatVersion: 2
+guid: ec9cf7702008ac648af0687c05064f78
+timeCreated: 1531219386
+licenseType: Free
+TextScriptImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

src/csharp/unitypackage/unitypackage_skeleton/Plugins/Grpc.Core/runtimes.meta

@@ -0,0 +1,10 @@
+fileFormatVersion: 2
+guid: 643bdb9ca01174f4eb77e3e15f8324b3
+folderAsset: yes
+timeCreated: 1531219385
+licenseType: Free
+DefaultImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

src/csharp/unitypackage/unitypackage_skeleton/Plugins/Grpc.Core/runtimes/android.meta

@@ -0,0 +1,10 @@
+fileFormatVersion: 2
+guid: f7f79be62cf24a940be0211dab5d2e5e
+folderAsset: yes
+timeCreated: 1531220113
+licenseType: Free
+DefaultImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

src/csharp/unitypackage/unitypackage_skeleton/Plugins/Grpc.Core/runtimes/android/arm64-v8a.meta

@@ -0,0 +1,8 @@
+fileFormatVersion: 2
+guid: 47ba39f5fad6b49c5aae011940e9eea2
+folderAsset: yes
+DefaultImporter:
+  externalObjects: {}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

src/csharp/unitypackage/unitypackage_skeleton/Plugins/Grpc.Core/runtimes/android/arm64-v8a/libgrpc_csharp_ext.so.meta

@@ -0,0 +1,102 @@
+fileFormatVersion: 2
+guid: e5beceb1c8fb2403ab3dea319dcd9a2e
+PluginImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  iconMap: {}
+  executionOrder: {}
+  isPreloaded: 0
+  isOverridable: 0
+  platformData:
+  - first:
+      '': Any
+    second:
+      enabled: 0
+      settings:
+        Exclude Android: 0
+        Exclude Editor: 1
+        Exclude Linux: 1
+        Exclude Linux64: 1
+        Exclude LinuxUniversal: 1
+        Exclude OSXUniversal: 1
+        Exclude Win: 1
+        Exclude Win64: 1
+        Exclude iOS: 1
+  - first:
+      Android: Android
+    second:
+      enabled: 1
+      settings:
+        CPU: ARM64
+  - first:
+      Any: 
+    second:
+      enabled: 0
+      settings: {}
+  - first:
+      Editor: Editor
+    second:
+      enabled: 0
+      settings:
+        CPU: AnyCPU
+        DefaultValueInitialized: true
+        OS: AnyOS
+  - first:
+      Facebook: Win
+    second:
+      enabled: 0
+      settings:
+        CPU: AnyCPU
+  - first:
+      Facebook: Win64
+    second:
+      enabled: 0
+      settings:
+        CPU: AnyCPU
+  - first:
+      Standalone: Linux
+    second:
+      enabled: 0
+      settings:
+        CPU: x86
+  - first:
+      Standalone: Linux64
+    second:
+      enabled: 0
+      settings:
+        CPU: x86_64
+  - first:
+      Standalone: LinuxUniversal
+    second:
+      enabled: 0
+      settings:
+        CPU: None
+  - first:
+      Standalone: OSXUniversal
+    second:
+      enabled: 0
+      settings:
+        CPU: AnyCPU
+  - first:
+      Standalone: Win
+    second:
+      enabled: 0
+      settings:
+        CPU: AnyCPU
+  - first:
+      Standalone: Win64
+    second:
+      enabled: 0
+      settings:
+        CPU: AnyCPU
+  - first:
+      iPhone: iOS
+    second:
+      enabled: 0
+      settings:
+        AddToEmbeddedBinaries: false
+        CompileFlags: 
+        FrameworkDependencies: 
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: