Merge branch 'we-dont-need-no-backup' into one-shouldnt-depend-on-protobufs

Conflicts:
	include/grpc++/async_unary_call.h
	include/grpc++/config.h
	include/grpc++/config_protobuf.h
	include/grpc++/impl/service_type.h
	include/grpc++/stream.h
	src/cpp/common/call.cc

BUILD

@@ -154,7 +154,6 @@ cc_library(
     "src/core/channel/http_client_filter.h",
     "src/core/channel/http_server_filter.h",
     "src/core/channel/noop_filter.h",
-    "src/core/compression/algorithm.h",
     "src/core/compression/message_compress.h",
     "src/core/debug/trace.h",
     "src/core/iomgr/alarm.h",
@@ -349,6 +348,7 @@ cc_library(
     "include/grpc/grpc_security.h",
     "include/grpc/byte_buffer.h",
     "include/grpc/byte_buffer_reader.h",
+    "include/grpc/compression.h",
     "include/grpc/grpc.h",
     "include/grpc/status.h",
     "include/grpc/census.h",
@@ -377,7 +377,6 @@ cc_library(
     "src/core/channel/http_client_filter.h",
     "src/core/channel/http_server_filter.h",
     "src/core/channel/noop_filter.h",
-    "src/core/compression/algorithm.h",
     "src/core/compression/message_compress.h",
     "src/core/debug/trace.h",
     "src/core/iomgr/alarm.h",
@@ -549,6 +548,7 @@ cc_library(
   hdrs = [
     "include/grpc/byte_buffer.h",
     "include/grpc/byte_buffer_reader.h",
+    "include/grpc/compression.h",
     "include/grpc/grpc.h",
     "include/grpc/status.h",
     "include/grpc/census.h",

build.json

@@ -101,6 +101,7 @@
       "public_headers": [
         "include/grpc/byte_buffer.h",
         "include/grpc/byte_buffer_reader.h",
+        "include/grpc/compression.h",
         "include/grpc/grpc.h",
         "include/grpc/status.h"
       ],
@@ -115,7 +116,6 @@
         "src/core/channel/http_client_filter.h",
         "src/core/channel/http_server_filter.h",
         "src/core/channel/noop_filter.h",
-        "src/core/compression/algorithm.h",
         "src/core/compression/message_compress.h",
         "src/core/debug/trace.h",
         "src/core/iomgr/alarm.h",
@@ -703,6 +703,7 @@
       "language": "c++",
       "headers": [
         "test/cpp/qps/driver.h",
+        "test/cpp/qps/interarrival.h",
         "test/cpp/qps/qps_worker.h",
         "test/cpp/qps/report.h",
         "test/cpp/qps/timer.h"
@@ -1362,6 +1363,9 @@
         "grpc",
         "gpr_test_util",
         "gpr"
+      ],
+      "platforms": [
+        "posix"
       ]
     },
     {
@@ -2075,9 +2079,27 @@
         "grpc++_benchmark_config"
       ]
     },
+    {
+      "name": "qps_interarrival_test",
+      "build": "test",
+      "run": false,
+      "language": "c++",
+      "src": [
+        "test/cpp/qps/qps_interarrival_test.cc"
+      ],
+      "deps": [
+        "qps",
+        "grpc++_test_util",
+        "grpc_test_util",
+        "grpc++",
+        "grpc",
+        "gpr_test_util",
+        "gpr"
+      ]
+    },
     {
       "name": "qps_test",
-      "build": "benchmark",
+      "build": "test",
       "language": "c++",
       "src": [
         "test/cpp/qps/qps_test.cc"
@@ -2094,6 +2116,25 @@
         "grpc++_test_config"
       ]
     },
+    {
+      "name": "qps_test_openloop",
+      "build": "test",
+      "language": "c++",
+      "src": [
+        "test/cpp/qps/qps_test_openloop.cc"
+      ],
+      "deps": [
+        "qps",
+        "grpc++_test_util",
+        "grpc++_benchmark_config",
+        "grpc_test_util",
+        "grpc++",
+        "grpc",
+        "gpr_test_util",
+        "gpr",
+        "grpc++_test_config"
+      ]
+    },
     {
       "name": "qps_worker",
       "build": "benchmark",

doc/connectivity-semantics-and-api.md

@@ -0,0 +1,147 @@
+gRPC Connectivity Semantics and API
+===================================
+
+This document describes the connectivity semantics for gRPC channels and the
+corresponding impact on RPCs. We then discuss an API.
+
+States of Connectivity
+----------------------
+
+gRPC Channels provide the abstraction over which clients can communicate with
+servers.The client-side channel object can be constructed using little more
+than a DNS name. Channels encapsulate a range of functionality including name
+resolution, establishing a TCP connection (with retries and backoff) and TLS
+handshakes. Channels can also handle errors on established connections and
+reconnect, or in the case of HTTP/2 GO_AWAY, re-resolve the name and reconnect.
+
+To hide the details of all this activity from the user of the gRPC API (i.e.,
+application code) while exposing meaningful information about the state of a
+channel, we use a state machine with four states, defined below:
+
+CONNECTING: The channel is trying to establish a connection and is waiting to
+make progress on one of the steps involved in name resolution, TCP connection
+establishment or TLS handshake. This may be used as the initial state for channels upon
+creation.
+
+READY: The channel has successfully established a connection all the way
+through TLS handshake (or equivalent) and all subsequent attempt to communicate
+have succeeded (or are pending without any known failure ).
+
+TRANSIENT_FAILURE: There has been some transient failure (such as a TCP 3-way
+handshake timing out or a socket error). Channels in this state will eventually
+switch to the CONNECTING state and try to establish a connection again. Since
+retries are done with exponential backoff, channels that fail to connect will
+start out spending very little time in this state but as the attempts fail
+repeatedly, the channel will spend increasingly large amounts of time in this
+state. For many non-fatal failures (e.g., TCP connection attempts timing out
+because the server is not yet available), the channel may spend increasingly
+large amounts of time in this state.
+
+IDLE: This is the state where the channel is not even trying to create a
+connection because of a lack of new or pending RPCs. New channels MAY be created
+in this state. Any attempt to start an RPC on the channel will push the channel
+out of this state to connecting. When there has been no RPC activity on a channel
+for a specified IDLE_TIMEOUT, i.e., no new or pending (active) RPCs for this
+period, channels that are READY or CONNECTING switch to IDLE. Additionaly,
+channels that receive a GOAWAY when there are no active or pending RPCs should
+also switch to IDLE to avoid connection overload at servers that are attempting
+to shed connections. We will use a default IDLE_TIMEOUT of 300 seconds (5 minutes).
+
+SHUTDOWN: This channel has started shutting down. Any new RPCs should fail
+immediately. Pending RPCs may continue running till the application cancels them.
+Channels may enter this state either because the application explicitly requested
+a shutdown or if a non-recoverable error has happened during attempts to connect
+communicate . (As of 6/12/2015, there are no known errors (while connecting or
+communicating) that are classified as non-recoverable) 
+Channels that enter this state never leave this state. 
+
+The following table lists the legal transitions from one state to another and
+corresponding reasons. Empty cells denote disallowed transitions.
+
+<table style='border: 1px solid black'>
+  <tr>
+    <th>From/To</th>
+    <th>CONNECTING</th>
+    <th>READY</th>
+    <th>TRANSIENT_FAILURE</th>
+    <th>IDLE</th>
+    <th>SHUTDOWN</th>
+  </tr>
+  <tr>
+    <th>CONNECTING</th>
+    <td>Incremental progress during connection establishment</td>
+    <td>All steps needed to establish a connection succeeded</td>
+    <td>Any failure in any of the steps needed to establish connection</td>
+    <td>No RPC activity on channel for IDLE_TIMEOUT</td>
+    <td>Shutdown triggered by application.</td>
+  </tr>
+  <tr>
+    <th>READY</th>
+    <td></td>
+    <td>Incremental successful communication on established channel.</td>
+    <td>Any failure encountered while expecting successful communication on
+        established channel.</td>
+    <td>No RPC activity on channel for IDLE_TIMEOUT <br>OR<br>upon receiving a GOAWAY while there are no pending RPCs.</td>
+    <td>Shutdown triggered by application.</td>
+  </tr>
+  <tr>
+    <th>TRANSIENT_FAILURE</th>
+    <td>Wait time required to implement (exponential) backoff is over.</td>
+    <td></td>
+    <td></td>
+    <td></td>
+    <td>Shutdown triggered by application.</td>
+  </tr>
+  <tr>
+    <th>IDLE</th>
+    <td>Any new RPC activity on the channel</td>
+    <td></td>
+    <td></td>
+    <td></td>
+    <td>Shutdown triggered by application.</td>
+  </tr>
+  <tr>
+    <th>FATAL_FAILURE</th>
+    <td></td>
+    <td></td>
+    <td></td>
+    <td></td>
+    <td></td>
+  </tr>
+</table>
+
+
+Channel State API
+-----------------
+
+All gRPC libraries will expose a channel-level API method to poll the current
+state of a channel. In C++, this method is called GetCurrentState and returns
+an enum for one of the four legal states.
+
+All libraries should also expose an API that enables the application (user of
+the gRPC API) to be notified when the channel state changes. Since state
+changes can be rapid and race with any such notification, the notification
+should just inform the user that some state change has happened, leaving it to
+the user to poll the channel for the current state.
+
+The synchronous version of this API is:
+
+```cpp
+bool WaitForStateChange(gpr_timespec deadline, ChannelState source_state);
+```
+
+which returns true when the state changes to something other than the
+source_state and false if the deadline expires. Asynchronous and futures based
+APIs should have a corresponding method that allows the application to be
+notified when the state of a channel changes.
+
+Note that a notification is delivered every time there is a transition from any
+state to any *other* state. On the other hand the rules for legal state
+transition, require a transition from CONNECTING to TRANSIENT_FAILURE and back
+to CONNECTING for every recoverable failure, even if the corresponding
+exponential backoff requires no wait before retry. The combined effect is that
+the application may receive state change notifications that appear spurious.
+e.g., an application waiting for state changes on a channel that is CONNECTING
+may receive a state change notification but find the channel in the same
+CONNECTING state on polling for current state because the channel may have
+spent infinitesimally small amount of time in the TRANSIENT_FAILURE state.

gRPC.podspec

@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
   s.name     = 'gRPC'
-  s.version  = '0.5.1'
+  s.version  = '0.6.0'
   s.summary  = 'gRPC client library for iOS/OSX'
   s.homepage = 'http://www.grpc.io'
   s.license  = 'New BSD'

include/grpc++/async_unary_call.h

@@ -64,7 +64,7 @@ class ClientAsyncResponseReader GRPC_FINAL
       : context_(context), call_(channel->CreateCall(method, context, cq)) {
     init_buf_.SendInitialMetadata(context->send_initial_metadata_);
     // TODO(ctiller): don't assert
-    GPR_ASSERT(init_buf_.SendMessage(request).IsOk());
+    GPR_ASSERT(init_buf_.SendMessage(request).ok());
     init_buf_.ClientSendClose();
     call_.PerformOps(&init_buf_);
   }
@@ -120,7 +120,7 @@ class ServerAsyncResponseWriter GRPC_FINAL
       ctx_->sent_initial_metadata_ = true;
     }
     // The response is dropped if the status is not OK.
-    if (status.IsOk()) {
+    if (status.ok()) {
       finish_buf_.ServerSendStatus(
           ctx_->trailing_metadata_, finish_buf_.SendMessage(msg));
     } else {
@@ -130,7 +130,7 @@ class ServerAsyncResponseWriter GRPC_FINAL
   }
 
   void FinishWithError(const Status& status, void* tag) {
-    GPR_ASSERT(!status.IsOk());
+    GPR_ASSERT(!status.ok());
     finish_buf_.set_output_tag(tag);
     if (!ctx_->sent_initial_metadata_) {
       finish_buf_.SendInitialMetadata(ctx_->initial_metadata_);

include/grpc++/byte_buffer.h

@@ -35,6 +35,7 @@
 #define GRPCXX_BYTE_BUFFER_H
 
 #include <grpc/grpc.h>
+#include <grpc/byte_buffer.h>
 #include <grpc/support/log.h>
 #include <grpc++/config.h>
 #include <grpc++/slice.h>

include/grpc++/client_context.h

@@ -41,6 +41,7 @@
 #include <grpc/support/log.h>
 #include <grpc/support/time.h>
 #include <grpc++/config.h>
+#include <grpc++/status.h>
 #include <grpc++/time.h>
 
 struct grpc_call;
@@ -52,7 +53,6 @@ class ChannelInterface;
 class CompletionQueue;
 class Credentials;
 class RpcMethod;
-class Status;
 template <class R>
 class ClientReader;
 template <class W>

include/grpc++/impl/call.h

@@ -151,7 +151,7 @@ class CallOpRecvMessage {
         got_message = true;
         *status = SerializationTraits<R>::Deserialize(recv_buf_, message_,
                                                       max_message_size)
-                      .IsOk();
+                      .ok();
       } else {
         got_message = false;
         grpc_byte_buffer_destroy(recv_buf_);
@@ -196,7 +196,7 @@ class CallOpGenericRecvMessage {
     if (recv_buf_) {
       if (*status) {
         got_message = true;
-        *status = deserialize_(recv_buf_, max_message_size).IsOk();
+        *status = deserialize_(recv_buf_, max_message_size).ok();
       } else {
         got_message = false;
         grpc_byte_buffer_destroy(recv_buf_);
@@ -241,8 +241,8 @@ class CallOpServerSendStatus {
     trailing_metadata_count_ = trailing_metadata.size();
     trailing_metadata_ = FillMetadataArray(trailing_metadata);
     send_status_available_ = true;
-    send_status_code_ = static_cast<grpc_status_code>(status.code());
-    send_status_details_ = status.details();
+    send_status_code_ = static_cast<grpc_status_code>(status.error_code());
+    send_status_details_ = status.error_message();
   }
 
  protected:

include/grpc++/impl/client_unary_call.h

@@ -35,6 +35,7 @@
 #define GRPCXX_IMPL_CLIENT_UNARY_CALL_H
 
 #include <grpc++/config.h>
+#include <grpc++/status.h>
 
 #include <grpc++/impl/call.h>
 
@@ -44,7 +45,6 @@ class ChannelInterface;
 class ClientContext;
 class CompletionQueue;
 class RpcMethod;
-class Status;
 
 // Wrapper that performs a blocking unary call
 template <class InputMessage, class OutputMessage>
@@ -57,7 +57,7 @@ Status BlockingUnaryCall(ChannelInterface* channel, const RpcMethod& method,
             CallOpRecvInitialMetadata, CallOpRecvMessage<OutputMessage>,
             CallOpClientSendClose, CallOpClientRecvStatus> ops;
   Status status = ops.SendMessage(request);
-  if (!status.IsOk()) {
+  if (!status.ok()) {
     return status;
   }
   ops.SendInitialMetadata(context->send_initial_metadata_);
@@ -66,7 +66,7 @@ Status BlockingUnaryCall(ChannelInterface* channel, const RpcMethod& method,
   ops.ClientSendClose();
   ops.ClientRecvStatus(context, &status);
   call.PerformOps(&ops);
-  GPR_ASSERT((cq.Pluck(&ops) && ops.got_message) || !status.IsOk());
+  GPR_ASSERT((cq.Pluck(&ops) && ops.got_message) || !status.ok());
   return status;
 }
 

include/grpc++/impl/rpc_service_method.h

@@ -85,7 +85,7 @@ class RpcMethodHandler : public MethodHandler {
     Status status = SerializationTraits<RequestType>::Deserialize(
         param.request, &req, param.max_message_size);
     ResponseType rsp;
-    if (status.IsOk()) {
+    if (status.ok()) {
       status = func_(service_, param.server_context, &req, &rsp);
     }
 
@@ -93,7 +93,7 @@ class RpcMethodHandler : public MethodHandler {
     CallOpSet<CallOpSendInitialMetadata, CallOpSendMessage,
               CallOpServerSendStatus> ops;
     ops.SendInitialMetadata(param.server_context->initial_metadata_);
-    if (status.IsOk()) {
+    if (status.ok()) {
       status = ops.SendMessage(rsp);
     }
     ops.ServerSendStatus(param.server_context->trailing_metadata_, status);
@@ -128,7 +128,7 @@ class ClientStreamingHandler : public MethodHandler {
     CallOpSet<CallOpSendInitialMetadata, CallOpSendMessage,
               CallOpServerSendStatus> ops;
     ops.SendInitialMetadata(param.server_context->initial_metadata_);
-    if (status.IsOk()) {
+    if (status.ok()) {
       status = ops.SendMessage(rsp);
     }
     ops.ServerSendStatus(param.server_context->trailing_metadata_, status);
@@ -157,7 +157,7 @@ class ServerStreamingHandler : public MethodHandler {
     Status status = SerializationTraits<RequestType>::Deserialize(
         param.request, &req, param.max_message_size);
 
-    if (status.IsOk()) {
+    if (status.ok()) {
       ServerWriter<ResponseType> writer(param.call, param.server_context);
       status = func_(service_, param.server_context, &req, &writer);
     }

include/grpc++/impl/service_type.h

@@ -37,6 +37,7 @@
 #include <grpc++/config.h>
 #include <grpc++/impl/serialization_traits.h>
 #include <grpc++/server.h>
+#include <grpc++/status.h>
 
 namespace grpc {
 
@@ -46,7 +47,6 @@ class RpcService;
 class Server;
 class ServerCompletionQueue;
 class ServerContext;
-class Status;
 
 class SynchronousService {
  public:

include/grpc++/server.h

@@ -163,7 +163,7 @@ class Server GRPC_FINAL : public GrpcLibrary, private CallHook {
           *status && payload_ &&
           SerializationTraits<Message>::Deserialize(payload_, request_,
                                                     server_->max_message_size_)
-              .IsOk();
+              .ok();
       bool ret = RegisteredAsyncRequest::FinalizeResult(tag, status);
       *status = serialization_status && *status;
       return ret;

include/grpc++/status.h

@@ -42,18 +42,17 @@ namespace grpc {
 class Status {
  public:
   Status() : code_(StatusCode::OK) {}
-  explicit Status(StatusCode code) : code_(code) {}
   Status(StatusCode code, const grpc::string& details)
       : code_(code), details_(details) {}
 
   // Pre-defined special status objects.
   static const Status& OK;
-  static const Status& Cancelled;
+  static const Status& CANCELLED;
 
-  StatusCode code() const { return code_; }
-  grpc::string details() const { return details_; }
+  StatusCode error_code() const { return code_; }
+  grpc::string error_message() const { return details_; }
 
-  bool IsOk() const { return code_ == StatusCode::OK; }
+  bool ok() const { return code_ == StatusCode::OK; }
 
  private:
   StatusCode code_;

include/grpc++/stream.h

@@ -101,7 +101,7 @@ class ClientReader GRPC_FINAL : public ClientReaderInterface<R> {
               CallOpClientSendClose> ops;
     ops.SendInitialMetadata(context->send_initial_metadata_);
     // TODO(ctiller): don't assert
-    GPR_ASSERT(ops.SendMessage(request).IsOk());
+    GPR_ASSERT(ops.SendMessage(request).ok());
     ops.ClientSendClose();
     call_.PerformOps(&ops);
     cq_.Pluck(&ops);
@@ -170,7 +170,7 @@ class ClientWriter : public ClientWriterInterface<W> {
 
   bool Write(const W& msg) GRPC_OVERRIDE {
     CallOpSet<CallOpSendMessage> ops;
-    if (!ops.SendMessage(msg).IsOk()) {
+    if (!ops.SendMessage(msg).ok()) {
       return false;
     }
     call_.PerformOps(&ops);
@@ -248,7 +248,7 @@ class ClientReaderWriter GRPC_FINAL : public ClientReaderWriterInterface<W, R> {
 
   bool Write(const W& msg) GRPC_OVERRIDE {
     CallOpSet<CallOpSendMessage> ops;
-    if (!ops.SendMessage(msg).IsOk()) return false;
+    if (!ops.SendMessage(msg).ok()) return false;
     call_.PerformOps(&ops);
     return cq_.Pluck(&ops);
   }
@@ -319,7 +319,7 @@ class ServerWriter GRPC_FINAL : public WriterInterface<W> {
 
   bool Write(const W& msg) GRPC_OVERRIDE {
     CallOpSet<CallOpSendInitialMetadata, CallOpSendMessage> ops;
-    if (!ops.SendMessage(msg).IsOk()) {
+    if (!ops.SendMessage(msg).ok()) {
       return false;
     }
     if (!ctx_->sent_initial_metadata_) {
@@ -361,7 +361,7 @@ class ServerReaderWriter GRPC_FINAL : public WriterInterface<W>,
 
   bool Write(const W& msg) GRPC_OVERRIDE {
     CallOpSet<CallOpSendInitialMetadata, CallOpSendMessage> ops;
-    if (!ops.SendMessage(msg).IsOk()) {
+    if (!ops.SendMessage(msg).ok()) {
       return false;
     }
     if (!ctx_->sent_initial_metadata_) {
@@ -422,7 +422,7 @@ class ClientAsyncReader GRPC_FINAL : public ClientAsyncReaderInterface<R> {
     init_ops_.set_output_tag(tag);
     init_ops_.SendInitialMetadata(context->send_initial_metadata_);
     // TODO(ctiller): don't assert
-    GPR_ASSERT(init_ops_.SendMessage(request).IsOk());
+    GPR_ASSERT(init_ops_.SendMessage(request).ok());
     init_ops_.ClientSendClose();
     call_.PerformOps(&init_ops_);
   }
@@ -496,7 +496,7 @@ class ClientAsyncWriter GRPC_FINAL : public ClientAsyncWriterInterface<W> {
   void Write(const W& msg, void* tag) GRPC_OVERRIDE {
     write_ops_.set_output_tag(tag);
     // TODO(ctiller): don't assert
-    GPR_ASSERT(write_ops_.SendMessage(msg).IsOk());
+    GPR_ASSERT(write_ops_.SendMessage(msg).ok());
     call_.PerformOps(&write_ops_);
   }
 
@@ -568,7 +568,7 @@ class ClientAsyncReaderWriter GRPC_FINAL
   void Write(const W& msg, void* tag) GRPC_OVERRIDE {
     write_ops_.set_output_tag(tag);
     // TODO(ctiller): don't assert
-    GPR_ASSERT(write_ops_.SendMessage(msg).IsOk());
+    GPR_ASSERT(write_ops_.SendMessage(msg).ok());
     call_.PerformOps(&write_ops_);
   }
 
@@ -627,7 +627,7 @@ class ServerAsyncReader GRPC_FINAL : public ServerAsyncStreamingInterface,
       ctx_->sent_initial_metadata_ = true;
     }
     // The response is dropped if the status is not OK.
-    if (status.IsOk()) {
+    if (status.ok()) {
       finish_ops_.ServerSendStatus(
           ctx_->trailing_metadata_,
           finish_ops_.SendMessage(msg));
@@ -638,7 +638,7 @@ class ServerAsyncReader GRPC_FINAL : public ServerAsyncStreamingInterface,
   }
 
   void FinishWithError(const Status& status, void* tag) {
-    GPR_ASSERT(!status.IsOk());
+    GPR_ASSERT(!status.ok());
     finish_ops_.set_output_tag(tag);
     if (!ctx_->sent_initial_metadata_) {
       finish_ops_.SendInitialMetadata(ctx_->initial_metadata_);
@@ -682,7 +682,7 @@ class ServerAsyncWriter GRPC_FINAL : public ServerAsyncStreamingInterface,
       ctx_->sent_initial_metadata_ = true;
     }
     // TODO(ctiller): don't assert
-    GPR_ASSERT(write_ops_.SendMessage(msg).IsOk());
+    GPR_ASSERT(write_ops_.SendMessage(msg).ok());
     call_.PerformOps(&write_ops_);
   }
 
@@ -737,7 +737,7 @@ class ServerAsyncReaderWriter GRPC_FINAL : public ServerAsyncStreamingInterface,
       ctx_->sent_initial_metadata_ = true;
     }
     // TODO(ctiller): don't assert
-    GPR_ASSERT(write_ops_.SendMessage(msg).IsOk());
+    GPR_ASSERT(write_ops_.SendMessage(msg).ok());
     call_.PerformOps(&write_ops_);
   }
 

include/grpc++/time.h

@@ -52,22 +52,22 @@ namespace grpc {
 template <typename T>
 class TimePoint {
  public:
-  TimePoint(const T& time) {
-    you_need_a_specialization_of_TimePoint();
-  }
+  TimePoint(const T& time) { you_need_a_specialization_of_TimePoint(); }
   gpr_timespec raw_time() {
     gpr_timespec t;
     return t;
   }
+
  private:
   void you_need_a_specialization_of_TimePoint();
 };
 
-template<>
+template <>
 class TimePoint<gpr_timespec> {
  public:
-  TimePoint(const gpr_timespec& time) : time_(time) { }
+  TimePoint(const gpr_timespec& time) : time_(time) {}
   gpr_timespec raw_time() { return time_; }
+
  private:
   gpr_timespec time_;
 };
@@ -85,6 +85,9 @@ namespace grpc {
 // from and to should be absolute time.
 void Timepoint2Timespec(const std::chrono::system_clock::time_point& from,
                         gpr_timespec* to);
+void TimepointHR2Timespec(
+    const std::chrono::high_resolution_clock::time_point& from,
+    gpr_timespec* to);
 
 std::chrono::system_clock::time_point Timespec2Timepoint(gpr_timespec t);
 
@@ -92,9 +95,10 @@ template <>
 class TimePoint<std::chrono::system_clock::time_point> {
  public:
   TimePoint(const std::chrono::system_clock::time_point& time) {
-	Timepoint2Timespec(time, &time_);
+    Timepoint2Timespec(time, &time_);
   }
   gpr_timespec raw_time() const { return time_; }
+
  private:
   gpr_timespec time_;
 };

include/grpc/byte_buffer.h

@@ -34,17 +34,77 @@
 #ifndef GRPC_BYTE_BUFFER_H
 #define GRPC_BYTE_BUFFER_H
 
-#include <grpc/grpc.h>
+#include <grpc/compression.h>
 #include <grpc/support/slice_buffer.h>
 
-typedef enum { GRPC_BB_SLICE_BUFFER } grpc_byte_buffer_type;
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef enum {
+  GRPC_BB_RAW
+  /* Future types may include GRPC_BB_PROTOBUF, etc. */
+} grpc_byte_buffer_type;
 
-/* byte buffers are containers for messages passed in from the public api's */
 struct grpc_byte_buffer {
   grpc_byte_buffer_type type;
   union {
-    gpr_slice_buffer slice_buffer;
+    struct {
+      grpc_compression_algorithm compression;
+      gpr_slice_buffer slice_buffer;
+    } raw;
   } data;
 };
+typedef struct grpc_byte_buffer grpc_byte_buffer;
+
+/** Returns a RAW byte buffer instance over the given slices (up to \a nslices).
+ *
+ * Increases the reference count for all \a slices processed. The user is
+ * responsible for invoking grpc_byte_buffer_destroy on the returned instance.*/
+grpc_byte_buffer *grpc_raw_byte_buffer_create(gpr_slice *slices,
+                                              size_t nslices);
+
+/** Returns a *compressed* RAW byte buffer instance over the given slices (up to
+ * \a nslices). The \a compression argument defines the compression algorithm
+ * used to generate the data in \a slices.
+ *
+ * Increases the reference count for all \a slices processed. The user is
+ * responsible for invoking grpc_byte_buffer_destroy on the returned instance.*/
+grpc_byte_buffer *grpc_raw_compressed_byte_buffer_create(
+    gpr_slice *slices, size_t nslices, grpc_compression_algorithm compression);
+
+/** Copies input byte buffer \a bb.
+ *
+ * Increases the reference count of all the source slices. The user is
+ * responsible for calling grpc_byte_buffer_destroy over the returned copy. */
+grpc_byte_buffer *grpc_byte_buffer_copy(grpc_byte_buffer *bb);
+
+/** Returns the size of the given byte buffer, in bytes. */
+size_t grpc_byte_buffer_length(grpc_byte_buffer *bb);
+
+/** Destroys \a byte_buffer deallocating all its memory. */
+void grpc_byte_buffer_destroy(grpc_byte_buffer *byte_buffer);
+
+
+/** Reader for byte buffers. Iterates over slices in the byte buffer */
+struct grpc_byte_buffer_reader;
+typedef struct grpc_byte_buffer_reader grpc_byte_buffer_reader;
+
+/** Initialize \a reader to read over \a buffer */
+void grpc_byte_buffer_reader_init(grpc_byte_buffer_reader *reader,
+                                  grpc_byte_buffer *buffer);
+
+/** Cleanup and destroy \a reader */
+void grpc_byte_buffer_reader_destroy(grpc_byte_buffer_reader *reader);
+
+/** Updates \a slice with the next piece of data from from \a reader and returns
+ * 1. Returns 0 at the end of the stream. Caller is responsible for calling
+ * gpr_slice_unref on the result. */
+int grpc_byte_buffer_reader_next(grpc_byte_buffer_reader *reader,
+                                 gpr_slice *slice);
+
+#ifdef __cplusplus
+}
+#endif
 
 #endif  /* GRPC_BYTE_BUFFER_H */

include/grpc/byte_buffer_reader.h

@@ -37,8 +37,13 @@
 #include <grpc/grpc.h>
 #include <grpc/byte_buffer.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 struct grpc_byte_buffer_reader {
-  grpc_byte_buffer *buffer;
+  grpc_byte_buffer *buffer_in;
+  grpc_byte_buffer *buffer_out;
   /* Different current objects correspond to different types of byte buffers */
   union {
     /* Index into a slice buffer's array of slices */
@@ -46,4 +51,8 @@ struct grpc_byte_buffer_reader {
   } current;
 };
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif  /* GRPC_BYTE_BUFFER_READER_H */

include/grpc/census.h

@@ -40,6 +40,10 @@
 
 #include <grpc/grpc.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /* Identify census functionality that can be enabled via census_initialize(). */
 enum census_functions {
   CENSUS_NONE = 0,    /* Do not enable census. */
@@ -92,4 +96,8 @@ int census_context_deserialize(const char *buffer, census_context **context);
  * future census calls will result in undefined behavior. */
 void census_context_destroy(census_context *context);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* CENSUS_CENSUS_H */

src/core/compression/algorithm.h → include/grpc/compression.h

@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef GRPC_INTERNAL_CORE_COMPRESSION_ALGORITHM_H
-#define GRPC_INTERNAL_CORE_COMPRESSION_ALGORITHM_H
+#ifndef GRPC_COMPRESSION_H
+#define GRPC_COMPRESSION_H
 
 /* The various compression algorithms supported by GRPC */
 typedef enum {
@@ -46,4 +46,4 @@ typedef enum {
 const char *grpc_compression_algorithm_name(
     grpc_compression_algorithm algorithm);
 
-#endif  /* GRPC_INTERNAL_CORE_COMPRESSION_ALGORITHM_H */
+#endif  /* GRPC_COMPRESSION_H */

include/grpc/grpc.h

@@ -37,6 +37,7 @@
 #include <grpc/status.h>
 
 #include <stddef.h>
+#include <grpc/byte_buffer.h>
 #include <grpc/support/slice.h>
 #include <grpc/support/time.h>
 
@@ -143,7 +144,10 @@ typedef enum grpc_call_error {
   /* the flags value was illegal for this call */
   GRPC_CALL_ERROR_INVALID_FLAGS,
   /* invalid metadata was passed to this call */
-  GRPC_CALL_ERROR_INVALID_METADATA
+  GRPC_CALL_ERROR_INVALID_METADATA,
+  /* completion queue for notification has not been registered with the server
+     */
+  GRPC_CALL_ERROR_NOT_SERVER_COMPLETION_QUEUE
 } grpc_call_error;
 
 /* Write Flags: */
@@ -154,34 +158,8 @@ typedef enum grpc_call_error {
 /* Force compression to be disabled for a particular write
    (start_write/add_metadata). Illegal on invoke/accept. */
 #define GRPC_WRITE_NO_COMPRESS (0x00000002u)
-
-/* A buffer of bytes */
-struct grpc_byte_buffer;
-typedef struct grpc_byte_buffer grpc_byte_buffer;
-
-/* Sample helpers to obtain byte buffers (these will certainly move
-   someplace else) */
-grpc_byte_buffer *grpc_byte_buffer_create(gpr_slice *slices, size_t nslices);
-grpc_byte_buffer *grpc_byte_buffer_copy(grpc_byte_buffer *bb);
-size_t grpc_byte_buffer_length(grpc_byte_buffer *bb);
-void grpc_byte_buffer_destroy(grpc_byte_buffer *byte_buffer);
-
-/* Reader for byte buffers. Iterates over slices in the byte buffer */
-struct grpc_byte_buffer_reader;
-typedef struct grpc_byte_buffer_reader grpc_byte_buffer_reader;
-
-/** Initialize \a reader to read over \a buffer */
-void grpc_byte_buffer_reader_init(grpc_byte_buffer_reader *reader,
-                                  grpc_byte_buffer *buffer);
-
-/** Cleanup and destroy \a reader */
-void grpc_byte_buffer_reader_destroy(grpc_byte_buffer_reader *reader);
-
-/* At the end of the stream, returns 0. Otherwise, returns 1 and sets slice to
-   be the returned slice. Caller is responsible for calling gpr_slice_unref on
-   the result. */
-int grpc_byte_buffer_reader_next(grpc_byte_buffer_reader *reader,
-                                 gpr_slice *slice);
+/* Mask of all valid flags. */
+#define GRPC_WRITE_USED_MASK (GRPC_WRITE_BUFFER_HINT | GRPC_WRITE_NO_COMPRESS)
 
 /* A single metadata element */
 typedef struct grpc_metadata {
@@ -248,7 +226,7 @@ typedef enum {
   GRPC_OP_SEND_INITIAL_METADATA = 0,
   /* Send a message: 0 or more of these operations can occur for each call */
   GRPC_OP_SEND_MESSAGE,
-  /* Send a close from the server: one and only one instance MUST be sent from
+  /* Send a close from the client: one and only one instance MUST be sent from
      the client,
      unless the call was cancelled - in which case this can be skipped */
   GRPC_OP_SEND_CLOSE_FROM_CLIENT,
@@ -267,7 +245,7 @@ typedef enum {
      the status will indicate some failure.
      */
   GRPC_OP_RECV_STATUS_ON_CLIENT,
-  /* Receive status on the server: one and only one must be made on the server
+  /* Receive close on the server: one and only one must be made on the server
      */
   GRPC_OP_RECV_CLOSE_ON_SERVER
 } grpc_op_type;
@@ -277,6 +255,7 @@ typedef enum {
    no arguments) */
 typedef struct grpc_op {
   grpc_op_type op;
+  gpr_uint32 flags;  /**< Write flags bitset for grpc_begin_messages */
   union {
     struct {
       size_t count;
@@ -361,7 +340,8 @@ grpc_completion_queue *grpc_completion_queue_create(void);
 /** Blocks until an event is available, the completion queue is being shut down,
     or deadline is reached.
 
-    Returns NULL on timeout, otherwise the event that occurred.
+    Returns a grpc_event with type GRPC_QUEUE_TIMEOUT on timeout,
+    otherwise a grpc_event describing the event that occurred.
 
     Callers must not call grpc_completion_queue_next and
     grpc_completion_queue_pluck simultaneously on the same completion queue. */
@@ -371,7 +351,8 @@ grpc_event grpc_completion_queue_next(grpc_completion_queue *cq,
 /** Blocks until an event with tag 'tag' is available, the completion queue is
     being shutdown or deadline is reached.
 
-    Returns NULL on timeout, or a pointer to the event that occurred.
+    Returns a grpc_event with type GRPC_QUEUE_TIMEOUT on timeout,
+    otherwise a grpc_event describing the event that occurred.
 
     Callers must not call grpc_completion_queue_next and
     grpc_completion_queue_pluck simultaneously on the same completion queue. */

include/grpc/grpc_security.h

@@ -34,8 +34,8 @@
 #ifndef GRPC_GRPC_SECURITY_H
 #define GRPC_GRPC_SECURITY_H
 
-#include "grpc.h"
-#include "status.h"
+#include <grpc/grpc.h>
+#include <grpc/status.h>
 
 #ifdef __cplusplus
 extern "C" {
@@ -117,7 +117,7 @@ grpc_credentials *grpc_service_account_credentials_create(
 grpc_credentials *grpc_jwt_credentials_create(const char *json_key,
                                               gpr_timespec token_lifetime);
 
-/* Creates an Oauth2 Refresh Token crednetials object. May return NULL if the
+/* Creates an Oauth2 Refresh Token credentials object. May return NULL if the
    input is invalid.
    WARNING: Do NOT use this credentials to connect to a non-google service as
    this could result in an oauth2 token leak.

include/grpc/support/slice.h

@@ -110,8 +110,9 @@ gpr_slice gpr_slice_ref(gpr_slice s);
 /* Decrement the ref count of s.  If the ref count of s reaches zero, all
    slices sharing the ref count are destroyed, and considered no longer
    initialized.  If s is ultimately derived from a call to gpr_slice_new(start,
-   len, dest) where dest!=NULL , then (*dest)(start, len) is called.  Requires
-   s initialized.  */
+   len, dest) where dest!=NULL , then (*dest)(start) is called, else if s is
+   ultimately derived from a call to gpr_slice_new_with_len(start, len, dest)
+   where dest!=NULL , then (*dest)(start, len).  Requires s initialized.  */
 void gpr_slice_unref(gpr_slice s);
 
 /* Create a slice pointing at some data. Calls malloc to allocate a refcount

include/grpc/support/tls_pthread.h

@@ -49,7 +49,13 @@ struct gpr_pthread_thread_local {
 
 #define gpr_tls_init(tls) GPR_ASSERT(0 == pthread_key_create(&(tls)->key, NULL))
 #define gpr_tls_destroy(tls) pthread_key_delete((tls)->key)
-gpr_intptr gpr_tls_set(struct gpr_pthread_thread_local *tls, gpr_intptr value);
 #define gpr_tls_get(tls) ((gpr_intptr)pthread_getspecific((tls)->key))
+#ifdef __cplusplus
+extern "C" {
+#endif
+gpr_intptr gpr_tls_set(struct gpr_pthread_thread_local *tls, gpr_intptr value);
+#ifdef __cplusplus
+}
+#endif
 
 #endif

src/compiler/cpp_generator.cc

@@ -839,9 +839,12 @@ void PrintSourceServerMethod(grpc::protobuf::io::Printer *printer,
                    "::grpc::Status $ns$$Service$::Service::$Method$("
                    "::grpc::ServerContext* context, "
                    "const $Request$* request, $Response$* response) {\n");
+    printer->Print("  (void) context;\n");
+    printer->Print("  (void) request;\n");
+    printer->Print("  (void) response;\n");
     printer->Print(
         "  return ::grpc::Status("
-        "::grpc::StatusCode::UNIMPLEMENTED);\n");
+        "::grpc::StatusCode::UNIMPLEMENTED, \"\");\n");
     printer->Print("}\n\n");
   } else if (ClientOnlyStreaming(method)) {
     printer->Print(*vars,
@@ -849,9 +852,12 @@ void PrintSourceServerMethod(grpc::protobuf::io::Printer *printer,
                    "::grpc::ServerContext* context, "
                    "::grpc::ServerReader< $Request$>* reader, "
                    "$Response$* response) {\n");
+    printer->Print("  (void) context;\n");
+    printer->Print("  (void) reader;\n");
+    printer->Print("  (void) response;\n");
     printer->Print(
         "  return ::grpc::Status("
-        "::grpc::StatusCode::UNIMPLEMENTED);\n");
+        "::grpc::StatusCode::UNIMPLEMENTED, \"\");\n");
     printer->Print("}\n\n");
   } else if (ServerOnlyStreaming(method)) {
     printer->Print(*vars,
@@ -859,9 +865,12 @@ void PrintSourceServerMethod(grpc::protobuf::io::Printer *printer,
                    "::grpc::ServerContext* context, "
                    "const $Request$* request, "
                    "::grpc::ServerWriter< $Response$>* writer) {\n");
+    printer->Print("  (void) context;\n");
+    printer->Print("  (void) request;\n");
+    printer->Print("  (void) writer;\n");
     printer->Print(
         "  return ::grpc::Status("
-        "::grpc::StatusCode::UNIMPLEMENTED);\n");
+        "::grpc::StatusCode::UNIMPLEMENTED, \"\");\n");
     printer->Print("}\n\n");
   } else if (BidiStreaming(method)) {
     printer->Print(*vars,
@@ -869,9 +878,11 @@ void PrintSourceServerMethod(grpc::protobuf::io::Printer *printer,
                    "::grpc::ServerContext* context, "
                    "::grpc::ServerReaderWriter< $Response$, $Request$>* "
                    "stream) {\n");
+    printer->Print("  (void) context;\n");
+    printer->Print("  (void) stream;\n");
     printer->Print(
         "  return ::grpc::Status("
-        "::grpc::StatusCode::UNIMPLEMENTED);\n");
+        "::grpc::StatusCode::UNIMPLEMENTED, \"\");\n");
     printer->Print("}\n\n");
   }
 }

src/core/channel/client_channel.c

@@ -102,10 +102,17 @@ struct call_data {
 static int prepare_activate(grpc_call_element *elem,
                             grpc_child_channel *on_child) {
   call_data *calld = elem->call_data;
+  channel_data *chand = elem->channel_data;
   if (calld->state == CALL_CANCELLED) return 0;
 
   /* no more access to calld->s.waiting allowed */
   GPR_ASSERT(calld->state == CALL_WAITING);
+
+  if (calld->s.waiting_op.bind_pollset) {
+    grpc_transport_setup_del_interested_party(chand->transport_setup,
+                                              calld->s.waiting_op.bind_pollset);
+  }
+
   calld->state = CALL_ACTIVE;
 
   /* create a child call */
@@ -199,6 +206,7 @@ static void cc_start_transport_op(grpc_call_element *elem,
         handle_op_after_cancellation(elem, op);
       } else {
         calld->state = CALL_WAITING;
+        calld->s.waiting_op.bind_pollset = NULL;
         if (chand->active_child) {
           /* channel is connected - use the connected stack */
           if (prepare_activate(elem, chand->active_child)) {
@@ -230,14 +238,14 @@ static void cc_start_transport_op(grpc_call_element *elem,
           }
           calld->s.waiting_op = *op;
           chand->waiting_children[chand->waiting_child_count++] = calld;
+          grpc_transport_setup_add_interested_party(chand->transport_setup,
+                                                    op->bind_pollset);
           gpr_mu_unlock(&chand->mu);
 
           /* finally initiate transport setup if needed */
           if (initiate_transport_setup) {
             grpc_transport_setup_initiate(chand->transport_setup);
           }
-          grpc_transport_setup_add_interested_party(chand->transport_setup,
-                                                    op->bind_pollset);
         }
       }
       break;

src/core/channel/client_setup.c

@@ -56,12 +56,12 @@ struct grpc_client_setup {
   gpr_cv cv;
   grpc_client_setup_request *active_request;
   int refs;
+  grpc_pollset_set interested_parties;
 };
 
 struct grpc_client_setup_request {
   /* pointer back to the setup object */
   grpc_client_setup *setup;
-  grpc_pollset_set interested_parties;
   gpr_timespec deadline;
 };
 
@@ -71,7 +71,7 @@ gpr_timespec grpc_client_setup_request_deadline(grpc_client_setup_request *r) {
 
 grpc_pollset_set *grpc_client_setup_get_interested_parties(
     grpc_client_setup_request *r) {
-  return &r->interested_parties;
+  return &r->setup->interested_parties;
 }
 
 static void destroy_setup(grpc_client_setup *s) {
@@ -79,11 +79,11 @@ static void destroy_setup(grpc_client_setup *s) {
   gpr_cv_destroy(&s->cv);
   s->done(s->user_data);
   grpc_channel_args_destroy(s->args);
+  grpc_pollset_set_destroy(&s->interested_parties);
   gpr_free(s);
 }
 
 static void destroy_request(grpc_client_setup_request *r) {
-  grpc_pollset_set_destroy(&r->interested_parties);
   gpr_free(r);
 }
 
@@ -94,7 +94,6 @@ static void setup_initiate(grpc_transport_setup *sp) {
   int in_alarm = 0;
 
   r->setup = s;
-  grpc_pollset_set_init(&r->interested_parties);
   /* TODO(klempner): Actually set a deadline */
   r->deadline = gpr_time_add(gpr_now(), gpr_time_from_seconds(60));
 
@@ -125,12 +124,8 @@ static void setup_add_interested_party(grpc_transport_setup *sp,
   grpc_client_setup *s = (grpc_client_setup *)sp;
 
   gpr_mu_lock(&s->mu);
-  if (!s->active_request) {
-    gpr_mu_unlock(&s->mu);
-    return;
-  }
 
-  grpc_pollset_set_add_pollset(&s->active_request->interested_parties, pollset);
+  grpc_pollset_set_add_pollset(&s->interested_parties, pollset);
 
   gpr_mu_unlock(&s->mu);
 }
@@ -140,12 +135,8 @@ static void setup_del_interested_party(grpc_transport_setup *sp,
   grpc_client_setup *s = (grpc_client_setup *)sp;
 
   gpr_mu_lock(&s->mu);
-  if (!s->active_request) {
-    gpr_mu_unlock(&s->mu);
-    return;
-  }
 
-  grpc_pollset_set_del_pollset(&s->active_request->interested_parties, pollset);
+  grpc_pollset_set_del_pollset(&s->interested_parties, pollset);
 
   gpr_mu_unlock(&s->mu);
 }
@@ -225,6 +216,7 @@ void grpc_client_setup_create_and_attach(
   s->in_alarm = 0;
   s->in_cb = 0;
   s->cancelled = 0;
+  grpc_pollset_set_init(&s->interested_parties);
 
   grpc_client_channel_set_transport_setup(newly_minted_channel, &s->base);
 }

src/core/compression/algorithm.c

@@ -31,7 +31,7 @@
  *
  */
 
-#include "src/core/compression/algorithm.h"
+#include <grpc/compression.h>
 
 const char *grpc_compression_algorithm_name(
     grpc_compression_algorithm algorithm) {

src/core/compression/message_compress.h

@@ -34,7 +34,7 @@
 #ifndef GRPC_INTERNAL_CORE_COMPRESSION_MESSAGE_COMPRESS_H
 #define GRPC_INTERNAL_CORE_COMPRESSION_MESSAGE_COMPRESS_H
 
-#include "src/core/compression/algorithm.h"
+#include <grpc/compression.h>
 #include <grpc/support/slice_buffer.h>
 
 /* compress 'input' to 'output' using 'algorithm'.

src/core/iomgr/pollset_multipoller_with_epoll.c

@@ -100,8 +100,9 @@ static int multipoll_with_epoll_pollset_maybe_work(
   if (gpr_time_cmp(deadline, gpr_inf_future) == 0) {
     timeout_ms = -1;
   } else {
-    timeout_ms = gpr_time_to_millis(gpr_time_sub(deadline, now));
-    if (timeout_ms <= 0) {
+    timeout_ms = gpr_time_to_millis(
+        gpr_time_add(gpr_time_sub(deadline, now), gpr_time_from_micros(500)));
+    if (timeout_ms < 0) {
       return 1;
     }
   }

src/core/iomgr/pollset_multipoller_with_poll_posix.c

@@ -116,8 +116,9 @@ static int multipoll_with_poll_pollset_maybe_work(
   if (gpr_time_cmp(deadline, gpr_inf_future) == 0) {
     timeout = -1;
   } else {
-    timeout = gpr_time_to_millis(gpr_time_sub(deadline, now));
-    if (timeout <= 0) {
+    timeout = gpr_time_to_millis(
+        gpr_time_add(gpr_time_sub(deadline, now), gpr_time_from_micros(500)));
+    if (timeout < 0) {
       return 1;
     }
   }

src/core/iomgr/pollset_posix.c

@@ -99,6 +99,7 @@ void grpc_pollset_init(grpc_pollset *pollset) {
   grpc_pollset_kick_init(&pollset->kick_state);
   pollset->in_flight_cbs = 0;
   pollset->shutting_down = 0;
+  pollset->called_shutdown = 0;
   become_basic_pollset(pollset, NULL);
 }
 
@@ -141,7 +142,8 @@ int grpc_pollset_work(grpc_pollset *pollset, gpr_timespec deadline) {
   if (pollset->shutting_down) {
     if (pollset->counter > 0) {
       grpc_pollset_kick(pollset);
-    } else if (pollset->in_flight_cbs == 0) {
+    } else if (!pollset->called_shutdown && pollset->in_flight_cbs == 0) {
+      pollset->called_shutdown = 1;
       gpr_mu_unlock(&pollset->mu);
       finish_shutdown(pollset);
       /* Continuing to access pollset here is safe -- it is the caller's
@@ -157,21 +159,22 @@ int grpc_pollset_work(grpc_pollset *pollset, gpr_timespec deadline) {
 void grpc_pollset_shutdown(grpc_pollset *pollset,
                            void (*shutdown_done)(void *arg),
                            void *shutdown_done_arg) {
-  int in_flight_cbs;
-  int counter;
+  int call_shutdown = 0;
   gpr_mu_lock(&pollset->mu);
   GPR_ASSERT(!pollset->shutting_down);
   pollset->shutting_down = 1;
-  in_flight_cbs = pollset->in_flight_cbs;
-  counter = pollset->counter;
+  if (!pollset->called_shutdown && pollset->in_flight_cbs == 0 && pollset->counter == 0) {
+    pollset->called_shutdown = 1;
+    call_shutdown = 1;
+  }
   pollset->shutdown_done_cb = shutdown_done;
   pollset->shutdown_done_arg = shutdown_done_arg;
-  if (counter > 0) {
+  if (pollset->counter > 0) {
     grpc_pollset_kick(pollset);
   }
   gpr_mu_unlock(&pollset->mu);
 
-  if (in_flight_cbs == 0 && counter == 0) {
+  if (call_shutdown) {
     finish_shutdown(pollset);
   }
 }
@@ -343,8 +346,9 @@ static int basic_pollset_maybe_work(grpc_pollset *pollset,
   if (gpr_time_cmp(deadline, gpr_inf_future) == 0) {
     timeout = -1;
   } else {
-    timeout = gpr_time_to_millis(gpr_time_sub(deadline, now));
-    if (timeout <= 0) {
+    timeout = gpr_time_to_millis(
+        gpr_time_add(gpr_time_sub(deadline, now), gpr_time_from_micros(500)));
+    if (timeout < 0) {
       return 1;
     }
   }

src/core/iomgr/pollset_posix.h

@@ -56,6 +56,7 @@ typedef struct grpc_pollset {
   int counter;
   int in_flight_cbs;
   int shutting_down;
+  int called_shutdown;
   void (*shutdown_done_cb)(void *arg);
   void *shutdown_done_arg;
   union {

src/core/iomgr/pollset_set_posix.c

@@ -49,7 +49,11 @@ void grpc_pollset_set_init(grpc_pollset_set *pollset_set) {
 }
 
 void grpc_pollset_set_destroy(grpc_pollset_set *pollset_set) {
+  size_t i;
   gpr_mu_destroy(&pollset_set->mu);
+  for (i = 0; i < pollset_set->fd_count; i++) {
+    GRPC_FD_UNREF(pollset_set->fds[i], "pollset");
+  }
   gpr_free(pollset_set->pollsets);
   gpr_free(pollset_set->fds);
 }
@@ -95,6 +99,7 @@ void grpc_pollset_set_add_fd(grpc_pollset_set *pollset_set, grpc_fd *fd) {
     pollset_set->fds = gpr_realloc(
         pollset_set->fds, pollset_set->fd_capacity * sizeof(*pollset_set->fds));
   }
+  GRPC_FD_REF(fd, "pollset_set");
   pollset_set->fds[pollset_set->fd_count++] = fd;
   for (i = 0; i < pollset_set->pollset_count; i++) {
     grpc_pollset_add_fd(pollset_set->pollsets[i], fd);
@@ -110,6 +115,7 @@ void grpc_pollset_set_del_fd(grpc_pollset_set *pollset_set, grpc_fd *fd) {
       pollset_set->fd_count--;
       GPR_SWAP(grpc_fd *, pollset_set->fds[i],
                pollset_set->fds[pollset_set->pollset_count]);
+      GRPC_FD_UNREF(fd, "pollset_set");
       break;
     }
   }

src/core/iomgr/pollset_set_windows.c

@@ -42,6 +42,9 @@ void grpc_pollset_set_init(grpc_pollset_set *pollset_set) {}
 void grpc_pollset_set_destroy(grpc_pollset_set *pollset_set) {}
 
 void grpc_pollset_set_add_pollset(grpc_pollset_set *pollset_set,
-                                  grpc_pollset *pollset) {}
+	grpc_pollset *pollset) {}
+
+void grpc_pollset_set_del_pollset(grpc_pollset_set *pollset_set,
+	grpc_pollset *pollset) {}
 
 #endif /* GPR_WINSOCK_SOCKET */

src/core/iomgr/pollset_windows.h

@@ -37,7 +37,6 @@
 #include <windows.h>
 #include <grpc/support/sync.h>
 
-#include "src/core/iomgr/pollset_kick.h"
 #include "src/core/iomgr/socket_windows.h"
 
 /* There isn't really any such thing as a pollset under Windows, due to the

src/core/support/log_win32.c

@@ -42,6 +42,7 @@
 #include <grpc/support/log_win32.h>
 #include <grpc/support/log.h>
 #include <grpc/support/time.h>
+#include <grpc/support/string_util.h>
 
 #include "src/core/support/string.h"
 #include "src/core/support/string_win32.h"
@@ -106,7 +107,7 @@ char *gpr_format_message(DWORD messageid) {
                                NULL, messageid,
                                MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
                                (LPTSTR)(&tmessage), 0, NULL);
-  if (status == 0) return gpr_strdup("Unable to retreive error string");
+  if (status == 0) return gpr_strdup("Unable to retrieve error string");
   message = gpr_tchar_to_char(tmessage);
   LocalFree(tmessage);
   return message;

src/core/surface/byte_buffer.c

@@ -35,25 +35,31 @@
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 
-grpc_byte_buffer *grpc_byte_buffer_create(gpr_slice *slices, size_t nslices) {
+grpc_byte_buffer *grpc_raw_byte_buffer_create(gpr_slice *slices,
+                                              size_t nslices) {
+  return grpc_raw_compressed_byte_buffer_create(slices, nslices,
+                                                GRPC_COMPRESS_NONE);
+}
+
+grpc_byte_buffer *grpc_raw_compressed_byte_buffer_create(
+    gpr_slice *slices, size_t nslices, grpc_compression_algorithm compression) {
   size_t i;
   grpc_byte_buffer *bb = malloc(sizeof(grpc_byte_buffer));
-
-  bb->type = GRPC_BB_SLICE_BUFFER;
-  gpr_slice_buffer_init(&bb->data.slice_buffer);
+  bb->type = GRPC_BB_RAW;
+  bb->data.raw.compression = compression;
+  gpr_slice_buffer_init(&bb->data.raw.slice_buffer);
   for (i = 0; i < nslices; i++) {
     gpr_slice_ref(slices[i]);
-    gpr_slice_buffer_add(&bb->data.slice_buffer, slices[i]);
+    gpr_slice_buffer_add(&bb->data.raw.slice_buffer, slices[i]);
   }
-
   return bb;
 }
 
 grpc_byte_buffer *grpc_byte_buffer_copy(grpc_byte_buffer *bb) {
   switch (bb->type) {
-    case GRPC_BB_SLICE_BUFFER:
-      return grpc_byte_buffer_create(bb->data.slice_buffer.slices,
-                                     bb->data.slice_buffer.count);
+    case GRPC_BB_RAW:
+      return grpc_raw_byte_buffer_create(bb->data.raw.slice_buffer.slices,
+                                         bb->data.raw.slice_buffer.count);
   }
   gpr_log(GPR_INFO, "should never get here");
   abort();
@@ -63,8 +69,8 @@ grpc_byte_buffer *grpc_byte_buffer_copy(grpc_byte_buffer *bb) {
 void grpc_byte_buffer_destroy(grpc_byte_buffer *bb) {
   if (!bb) return;
   switch (bb->type) {
-    case GRPC_BB_SLICE_BUFFER:
-      gpr_slice_buffer_destroy(&bb->data.slice_buffer);
+    case GRPC_BB_RAW:
+      gpr_slice_buffer_destroy(&bb->data.raw.slice_buffer);
       break;
   }
   free(bb);
@@ -72,8 +78,8 @@ void grpc_byte_buffer_destroy(grpc_byte_buffer *bb) {
 
 size_t grpc_byte_buffer_length(grpc_byte_buffer *bb) {
   switch (bb->type) {
-    case GRPC_BB_SLICE_BUFFER:
-      return bb->data.slice_buffer.length;
+    case GRPC_BB_RAW:
+      return bb->data.raw.slice_buffer.length;
   }
   gpr_log(GPR_ERROR, "should never reach here");
   abort();

src/core/surface/byte_buffer_reader.c

@@ -33,41 +33,73 @@
 
 #include <grpc/byte_buffer_reader.h>
 
+#include <grpc/compression.h>
 #include <grpc/grpc.h>
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 #include <grpc/support/slice_buffer.h>
 #include <grpc/byte_buffer.h>
 
+#include "src/core/compression/message_compress.h"
+
+static int is_compressed(grpc_byte_buffer *buffer) {
+  switch (buffer->type) {
+    case GRPC_BB_RAW:
+      if (buffer->data.raw.compression == GRPC_COMPRESS_NONE) {
+        return 0 /* GPR_FALSE */;
+      }
+      break;
+  }
+  return 1 /* GPR_TRUE */;
+}
+
 void grpc_byte_buffer_reader_init(grpc_byte_buffer_reader *reader,
                                   grpc_byte_buffer *buffer) {
-  reader->buffer = buffer;
-  switch (buffer->type) {
-    case GRPC_BB_SLICE_BUFFER:
+  gpr_slice_buffer decompressed_slices_buffer;
+  reader->buffer_in = buffer;
+  switch (reader->buffer_in->type) {
+    case GRPC_BB_RAW:
+      gpr_slice_buffer_init(&decompressed_slices_buffer);
+      if (is_compressed(reader->buffer_in)) {
+        grpc_msg_decompress(reader->buffer_in->data.raw.compression,
+                            &reader->buffer_in->data.raw.slice_buffer,
+                            &decompressed_slices_buffer);
+        reader->buffer_out = grpc_raw_byte_buffer_create(
+            decompressed_slices_buffer.slices,
+            decompressed_slices_buffer.count);
+        gpr_slice_buffer_destroy(&decompressed_slices_buffer);
+      } else {  /* not compressed, use the input buffer as output */
+        reader->buffer_out = reader->buffer_in;
+      }
       reader->current.index = 0;
+      break;
   }
 }
 
 void grpc_byte_buffer_reader_destroy(grpc_byte_buffer_reader *reader) {
-  /* no-op: the user is responsible for memory deallocation.
-   * Other cleanup operations would go here if needed. */
+  switch (reader->buffer_in->type) {
+    case GRPC_BB_RAW:
+      /* keeping the same if-else structure as in the init function */
+      if (is_compressed(reader->buffer_in)) {
+        grpc_byte_buffer_destroy(reader->buffer_out);
+      }
+      break;
+  }
 }
 
 int grpc_byte_buffer_reader_next(grpc_byte_buffer_reader *reader,
                                  gpr_slice *slice) {
-  grpc_byte_buffer *buffer = reader->buffer;
-  gpr_slice_buffer *slice_buffer;
-  switch (buffer->type) {
-    case GRPC_BB_SLICE_BUFFER:
-      slice_buffer = &buffer->data.slice_buffer;
+  switch (reader->buffer_in->type) {
+    case GRPC_BB_RAW: {
+      gpr_slice_buffer *slice_buffer;
+      slice_buffer = &reader->buffer_out->data.raw.slice_buffer;
       if (reader->current.index < slice_buffer->count) {
         *slice = gpr_slice_ref(slice_buffer->slices[reader->current.index]);
         reader->current.index += 1;
         return 1;
-      } else {
-        return 0;
       }
       break;
+    }
   }
   return 0;
 }

src/core/surface/call.c

@@ -99,6 +99,8 @@ typedef enum {
   /* Status came from 'the wire' - or somewhere below the surface
      layer */
   STATUS_FROM_WIRE,
+  /* Status came from the server sending status */
+  STATUS_FROM_SERVER_STATUS,
   STATUS_SOURCE_COUNT
 } status_source;
 
@@ -189,6 +191,7 @@ struct grpc_call {
      and a strong upper bound of a count of masters to be calculated. */
   gpr_uint8 request_set[GRPC_IOREQ_OP_COUNT];
   grpc_ioreq_data request_data[GRPC_IOREQ_OP_COUNT];
+  gpr_uint32 request_flags[GRPC_IOREQ_OP_COUNT];
   reqinfo_master masters[GRPC_IOREQ_OP_COUNT];
 
   /* Dynamic array of ioreq's that have completed: the count of
@@ -232,6 +235,7 @@ struct grpc_call {
 
   gpr_slice_buffer incoming_message;
   gpr_uint32 incoming_message_length;
+  gpr_uint32 incoming_message_flags;
   grpc_iomgr_closure destroy_closure;
 };
 
@@ -578,10 +582,18 @@ static void finish_live_ioreq_op(grpc_call *call, grpc_ioreq_op op,
             call->write_state = WRITE_STATE_WRITE_CLOSED;
           }
           break;
+        case GRPC_IOREQ_SEND_STATUS:
+          if (call->request_data[GRPC_IOREQ_SEND_STATUS].send_status.details !=
+              NULL) {
+            grpc_mdstr_unref(
+                call->request_data[GRPC_IOREQ_SEND_STATUS].send_status.details);
+            call->request_data[GRPC_IOREQ_SEND_STATUS].send_status.details =
+                NULL;
+          }
+          break;
         case GRPC_IOREQ_RECV_CLOSE:
         case GRPC_IOREQ_SEND_INITIAL_METADATA:
         case GRPC_IOREQ_SEND_TRAILING_METADATA:
-        case GRPC_IOREQ_SEND_STATUS:
         case GRPC_IOREQ_SEND_CLOSE:
           break;
         case GRPC_IOREQ_RECV_STATUS:
@@ -665,7 +677,7 @@ static void call_on_done_send(void *pc, int success) {
 
 static void finish_message(grpc_call *call) {
   /* TODO(ctiller): this could be a lot faster if coded directly */
-  grpc_byte_buffer *byte_buffer = grpc_byte_buffer_create(
+  grpc_byte_buffer *byte_buffer = grpc_raw_byte_buffer_create(
       call->incoming_message.slices, call->incoming_message.count);
   gpr_slice_buffer_reset_and_unref(&call->incoming_message);
 
@@ -699,6 +711,7 @@ static int begin_message(grpc_call *call, grpc_begin_message msg) {
   } else if (msg.length > 0) {
     call->reading_message = 1;
     call->incoming_message_length = msg.length;
+    call->incoming_message_flags = msg.flags;
     return 1;
   } else {
     finish_message(call);
@@ -788,7 +801,7 @@ static void call_on_done_recv(void *pc, int success) {
   unlock(call);
 
   GRPC_CALL_INTERNAL_UNREF(call, "receiving", 0);
-  GRPC_TIMER_BEGIN(GRPC_PTAG_CALL_ON_DONE_RECV, 0);
+  GRPC_TIMER_END(GRPC_PTAG_CALL_ON_DONE_RECV, 0);
 }
 
 static int prepare_application_metadata(grpc_call *call, size_t count,
@@ -835,9 +848,9 @@ static void copy_byte_buffer_to_stream_ops(grpc_byte_buffer *byte_buffer,
   size_t i;
 
   switch (byte_buffer->type) {
-    case GRPC_BB_SLICE_BUFFER:
-      for (i = 0; i < byte_buffer->data.slice_buffer.count; i++) {
-        gpr_slice slice = byte_buffer->data.slice_buffer.slices[i];
+    case GRPC_BB_RAW:
+      for (i = 0; i < byte_buffer->data.raw.slice_buffer.count; i++) {
+        gpr_slice slice = byte_buffer->data.raw.slice_buffer.slices[i];
         gpr_slice_ref(slice);
         grpc_sopb_add_slice(sopb, slice);
       }
@@ -847,9 +860,9 @@ static void copy_byte_buffer_to_stream_ops(grpc_byte_buffer *byte_buffer,
 
 static int fill_send_ops(grpc_call *call, grpc_transport_op *op) {
   grpc_ioreq_data data;
+  gpr_uint32 flags;
   grpc_metadata_batch mdb;
   size_t i;
-  char status_str[GPR_LTOA_MIN_BUFSIZE];
   GPR_ASSERT(op->send_ops == NULL);
 
   switch (call->write_state) {
@@ -873,8 +886,9 @@ static int fill_send_ops(grpc_call *call, grpc_transport_op *op) {
     case WRITE_STATE_STARTED:
       if (is_op_live(call, GRPC_IOREQ_SEND_MESSAGE)) {
         data = call->request_data[GRPC_IOREQ_SEND_MESSAGE];
+        flags = call->request_flags[GRPC_IOREQ_SEND_MESSAGE];
         grpc_sopb_add_begin_message(
-            &call->send_ops, grpc_byte_buffer_length(data.send_message), 0);
+            &call->send_ops, grpc_byte_buffer_length(data.send_message), flags);
         copy_byte_buffer_to_stream_ops(data.send_message, &call->send_ops);
         op->send_ops = &call->send_ops;
         call->last_send_contains |= 1 << GRPC_IOREQ_SEND_MESSAGE;
@@ -893,13 +907,10 @@ static int fill_send_ops(grpc_call *call, grpc_transport_op *op) {
           /* send status */
           /* TODO(ctiller): cache common status values */
           data = call->request_data[GRPC_IOREQ_SEND_STATUS];
-          gpr_ltoa(data.send_status.code, status_str);
           grpc_metadata_batch_add_tail(
               &mdb, &call->status_link,
-              grpc_mdelem_from_metadata_strings(
-                  call->metadata_context,
-                  grpc_mdstr_ref(grpc_channel_get_status_string(call->channel)),
-                  grpc_mdstr_from_string(call->metadata_context, status_str)));
+              grpc_channel_get_reffed_status_elem(call->channel,
+                                                  data.send_status.code));
           if (data.send_status.details) {
             grpc_metadata_batch_add_tail(
                 &mdb, &call->details_link,
@@ -907,8 +918,9 @@ static int fill_send_ops(grpc_call *call, grpc_transport_op *op) {
                     call->metadata_context,
                     grpc_mdstr_ref(
                         grpc_channel_get_message_string(call->channel)),
-                    grpc_mdstr_from_string(call->metadata_context,
-                                           data.send_status.details)));
+                    data.send_status.details));
+            call->request_data[GRPC_IOREQ_SEND_STATUS].send_status.details =
+                NULL;
           }
           grpc_sopb_add_metadata(&call->send_ops, mdb);
         }
@@ -1008,9 +1020,18 @@ static grpc_call_error start_ioreq(grpc_call *call, const grpc_ioreq *reqs,
                                  GRPC_CALL_ERROR_INVALID_METADATA);
       }
     }
+    if (op == GRPC_IOREQ_SEND_STATUS) {
+      set_status_code(call, STATUS_FROM_SERVER_STATUS,
+                      reqs[i].data.send_status.code);
+      if (reqs[i].data.send_status.details) {
+        set_status_details(call, STATUS_FROM_SERVER_STATUS,
+                           grpc_mdstr_ref(reqs[i].data.send_status.details));
+      }
+    }
     have_ops |= 1u << op;
 
     call->request_data[op] = data;
+    call->request_flags[op] = reqs[i].flags;
     call->request_set[op] = set;
   }
 
@@ -1227,6 +1248,14 @@ static void finish_batch_with_close(grpc_call *call, int success, void *tag) {
   grpc_cq_end_op(call->cq, tag, call, 1);
 }
 
+static int are_write_flags_valid(gpr_uint32 flags) {
+  /* check that only bits in GRPC_WRITE_(INTERNAL?)_USED_MASK are set */
+  const gpr_uint32 allowed_write_positions =
+      (GRPC_WRITE_USED_MASK | GRPC_WRITE_INTERNAL_USED_MASK);
+  const gpr_uint32 invalid_positions = ~allowed_write_positions;
+  return !(flags & invalid_positions);
+}
+
 grpc_call_error grpc_call_start_batch(grpc_call *call, const grpc_op *ops,
                                       size_t nops, void *tag) {
   grpc_ioreq reqs[GRPC_IOREQ_OP_COUNT];
@@ -1249,30 +1278,43 @@ grpc_call_error grpc_call_start_batch(grpc_call *call, const grpc_op *ops,
     op = &ops[in];
     switch (op->op) {
       case GRPC_OP_SEND_INITIAL_METADATA:
+        /* Flag validation: currently allow no flags */
+        if (op->flags != 0) return GRPC_CALL_ERROR_INVALID_FLAGS;
         req = &reqs[out++];
         req->op = GRPC_IOREQ_SEND_INITIAL_METADATA;
         req->data.send_metadata.count = op->data.send_initial_metadata.count;
         req->data.send_metadata.metadata =
             op->data.send_initial_metadata.metadata;
+        req->flags = op->flags;
         break;
       case GRPC_OP_SEND_MESSAGE:
+        if (!are_write_flags_valid(op->flags)){
+          return GRPC_CALL_ERROR_INVALID_FLAGS;
+        }
         req = &reqs[out++];
         req->op = GRPC_IOREQ_SEND_MESSAGE;
         req->data.send_message = op->data.send_message;
+        req->flags = ops->flags;
         break;
       case GRPC_OP_SEND_CLOSE_FROM_CLIENT:
+        /* Flag validation: currently allow no flags */
+        if (op->flags != 0) return GRPC_CALL_ERROR_INVALID_FLAGS;
         if (!call->is_client) {
           return GRPC_CALL_ERROR_NOT_ON_SERVER;
         }
         req = &reqs[out++];
         req->op = GRPC_IOREQ_SEND_CLOSE;
+        req->flags = op->flags;
         break;
       case GRPC_OP_SEND_STATUS_FROM_SERVER:
+        /* Flag validation: currently allow no flags */
+        if (op->flags != 0) return GRPC_CALL_ERROR_INVALID_FLAGS;
         if (call->is_client) {
           return GRPC_CALL_ERROR_NOT_ON_CLIENT;
         }
         req = &reqs[out++];
         req->op = GRPC_IOREQ_SEND_TRAILING_METADATA;
+        req->flags = op->flags;
         req->data.send_metadata.count =
             op->data.send_status_from_server.trailing_metadata_count;
         req->data.send_metadata.metadata =
@@ -1281,29 +1323,42 @@ grpc_call_error grpc_call_start_batch(grpc_call *call, const grpc_op *ops,
         req->op = GRPC_IOREQ_SEND_STATUS;
         req->data.send_status.code = op->data.send_status_from_server.status;
         req->data.send_status.details =
-            op->data.send_status_from_server.status_details;
+            op->data.send_status_from_server.status_details != NULL
+                ? grpc_mdstr_from_string(
+                      call->metadata_context,
+                      op->data.send_status_from_server.status_details)
+                : NULL;
         req = &reqs[out++];
         req->op = GRPC_IOREQ_SEND_CLOSE;
         break;
       case GRPC_OP_RECV_INITIAL_METADATA:
+        /* Flag validation: currently allow no flags */
+        if (op->flags != 0) return GRPC_CALL_ERROR_INVALID_FLAGS;
         if (!call->is_client) {
           return GRPC_CALL_ERROR_NOT_ON_SERVER;
         }
         req = &reqs[out++];
         req->op = GRPC_IOREQ_RECV_INITIAL_METADATA;
         req->data.recv_metadata = op->data.recv_initial_metadata;
+        req->flags = op->flags;
         break;
       case GRPC_OP_RECV_MESSAGE:
+        /* Flag validation: currently allow no flags */
+        if (op->flags != 0) return GRPC_CALL_ERROR_INVALID_FLAGS;
         req = &reqs[out++];
         req->op = GRPC_IOREQ_RECV_MESSAGE;
         req->data.recv_message = op->data.recv_message;
+        req->flags = op->flags;
         break;
       case GRPC_OP_RECV_STATUS_ON_CLIENT:
+        /* Flag validation: currently allow no flags */
+        if (op->flags != 0) return GRPC_CALL_ERROR_INVALID_FLAGS;
         if (!call->is_client) {
           return GRPC_CALL_ERROR_NOT_ON_SERVER;
         }
         req = &reqs[out++];
         req->op = GRPC_IOREQ_RECV_STATUS;
+        req->flags = op->flags;
         req->data.recv_status.set_value = set_status_value_directly;
         req->data.recv_status.user_data = op->data.recv_status_on_client.status;
         req = &reqs[out++];
@@ -1321,8 +1376,11 @@ grpc_call_error grpc_call_start_batch(grpc_call *call, const grpc_op *ops,
         finish_func = finish_batch_with_close;
         break;
       case GRPC_OP_RECV_CLOSE_ON_SERVER:
+        /* Flag validation: currently allow no flags */
+        if (op->flags != 0) return GRPC_CALL_ERROR_INVALID_FLAGS;
         req = &reqs[out++];
         req->op = GRPC_IOREQ_RECV_STATUS;
+        req->flags = op->flags;
         req->data.recv_status.set_value = set_cancelled_value;
         req->data.recv_status.user_data =
             op->data.recv_close_on_server.cancelled;

src/core/surface/call.h

@@ -72,13 +72,14 @@ typedef union {
   grpc_byte_buffer *send_message;
   struct {
     grpc_status_code code;
-    const char *details;
+    grpc_mdstr *details;
   } send_status;
 } grpc_ioreq_data;
 
 typedef struct {
   grpc_ioreq_op op;
   grpc_ioreq_data data;
+  gpr_uint32 flags;  /**< A copy of the write flags from grpc_op */
 } grpc_ioreq;
 
 typedef void (*grpc_ioreq_completion_func)(grpc_call *call, int success,

src/core/surface/channel.c

@@ -37,12 +37,20 @@
 #include <string.h>
 
 #include "src/core/iomgr/iomgr.h"
+#include "src/core/support/string.h"
 #include "src/core/surface/call.h"
 #include "src/core/surface/client.h"
 #include "src/core/surface/init.h"
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 
+/** Cache grpc-status: X mdelems for X = 0..NUM_CACHED_STATUS_ELEMS.
+ *  Avoids needing to take a metadata context lock for sending status
+ *  if the status code is <= NUM_CACHED_STATUS_ELEMS.
+ *  Sized to allow the most commonly used codes to fit in
+ *  (OK, Cancelled, Unknown). */
+#define NUM_CACHED_STATUS_ELEMS 3
+
 typedef struct registered_call {
   grpc_mdelem *path;
   grpc_mdelem *authority;
@@ -54,10 +62,13 @@ struct grpc_channel {
   gpr_refcount refs;
   gpr_uint32 max_message_length;
   grpc_mdctx *metadata_context;
+  /** mdstr for the grpc-status key */
   grpc_mdstr *grpc_status_string;
   grpc_mdstr *grpc_message_string;
   grpc_mdstr *path_string;
   grpc_mdstr *authority_string;
+  /** mdelem for grpc-status: 0 thru grpc-status: 2 */
+  grpc_mdelem *grpc_status_elem[NUM_CACHED_STATUS_ELEMS];
 
   gpr_mu registered_call_mu;
   registered_call *registered_calls;
@@ -88,6 +99,13 @@ grpc_channel *grpc_channel_create_from_filters(
   channel->metadata_context = mdctx;
   channel->grpc_status_string = grpc_mdstr_from_string(mdctx, "grpc-status");
   channel->grpc_message_string = grpc_mdstr_from_string(mdctx, "grpc-message");
+  for (i = 0; i < NUM_CACHED_STATUS_ELEMS; i++) {
+    char buf[GPR_LTOA_MIN_BUFSIZE];
+    gpr_ltoa(i, buf);
+    channel->grpc_status_elem[i] = grpc_mdelem_from_metadata_strings(
+        mdctx, grpc_mdstr_ref(channel->grpc_status_string),
+        grpc_mdstr_from_string(mdctx, buf));
+  }
   channel->path_string = grpc_mdstr_from_string(mdctx, ":path");
   channel->authority_string = grpc_mdstr_from_string(mdctx, ":authority");
   grpc_channel_stack_init(filters, num_filters, args, channel->metadata_context,
@@ -181,7 +199,11 @@ void grpc_channel_internal_ref(grpc_channel *c) {
 
 static void destroy_channel(void *p, int ok) {
   grpc_channel *channel = p;
+  size_t i;
   grpc_channel_stack_destroy(CHANNEL_STACK_FROM_CHANNEL(channel));
+  for (i = 0; i < NUM_CACHED_STATUS_ELEMS; i++) {
+    grpc_mdelem_unref(channel->grpc_status_elem[i]);
+  }
   grpc_mdstr_unref(channel->grpc_status_string);
   grpc_mdstr_unref(channel->grpc_message_string);
   grpc_mdstr_unref(channel->path_string);
@@ -247,6 +269,18 @@ grpc_mdstr *grpc_channel_get_status_string(grpc_channel *channel) {
   return channel->grpc_status_string;
 }
 
+grpc_mdelem *grpc_channel_get_reffed_status_elem(grpc_channel *channel, int i) {
+  if (i >= 0 && i < NUM_CACHED_STATUS_ELEMS) {
+    return grpc_mdelem_ref(channel->grpc_status_elem[i]);
+  } else {
+    char tmp[GPR_LTOA_MIN_BUFSIZE];
+    gpr_ltoa(i, tmp);
+    return grpc_mdelem_from_metadata_strings(
+        channel->metadata_context, grpc_mdstr_ref(channel->grpc_status_string),
+        grpc_mdstr_from_string(channel->metadata_context, tmp));
+  }
+}
+
 grpc_mdstr *grpc_channel_get_message_string(grpc_channel *channel) {
   return channel->grpc_message_string;
 }

src/core/surface/channel.h

@@ -40,8 +40,18 @@ grpc_channel *grpc_channel_create_from_filters(
     const grpc_channel_filter **filters, size_t count,
     const grpc_channel_args *args, grpc_mdctx *mdctx, int is_client);
 
+/** Get a (borrowed) pointer to this channels underlying channel stack */
 grpc_channel_stack *grpc_channel_get_channel_stack(grpc_channel *channel);
+
+/** Get a (borrowed) pointer to the channel wide metadata context */
 grpc_mdctx *grpc_channel_get_metadata_context(grpc_channel *channel);
+
+/** Get a grpc_mdelem of grpc-status: X where X is the numeric value of
+    status_code.
+
+    The returned elem is owned by the caller. */
+grpc_mdelem *grpc_channel_get_reffed_status_elem(grpc_channel *channel,
+                                                 int status_code);
 grpc_mdstr *grpc_channel_get_status_string(grpc_channel *channel);
 grpc_mdstr *grpc_channel_get_message_string(grpc_channel *channel);
 gpr_uint32 grpc_channel_get_max_message_length(grpc_channel *channel);

src/core/surface/completion_queue.c

@@ -73,6 +73,7 @@ struct grpc_completion_queue {
   event *queue;
   /* Fixed size chained hash table of events for pluck() */
   event *buckets[NUM_TAG_BUCKETS];
+  int is_server_cq;
 };
 
 grpc_completion_queue *grpc_completion_queue_create(void) {
@@ -323,3 +324,7 @@ void grpc_cq_hack_spin_pollset(grpc_completion_queue *cc) {
                     gpr_time_add(gpr_now(), gpr_time_from_millis(100)));
   gpr_mu_unlock(GRPC_POLLSET_MU(&cc->pollset));
 }
+
+void grpc_cq_mark_server_cq(grpc_completion_queue *cc) { cc->is_server_cq = 1; }
+
+int grpc_cq_is_server_cq(grpc_completion_queue *cc) { return cc->is_server_cq; }

src/core/surface/completion_queue.h

@@ -63,4 +63,7 @@ grpc_pollset *grpc_cq_pollset(grpc_completion_queue *cc);
 
 void grpc_cq_hack_spin_pollset(grpc_completion_queue *cc);
 
+void grpc_cq_mark_server_cq(grpc_completion_queue *cc);
+int grpc_cq_is_server_cq(grpc_completion_queue *cc);
+
 #endif /* GRPC_INTERNAL_CORE_SURFACE_COMPLETION_QUEUE_H */

src/core/surface/server.c

@@ -709,6 +709,7 @@ void grpc_server_register_completion_queue(grpc_server *server,
     if (server->cqs[i] == cq) return;
   }
   GRPC_CQ_INTERNAL_REF(cq, "server");
+  grpc_cq_mark_server_cq(cq);
   n = server->cq_count++;
   server->cqs = gpr_realloc(server->cqs,
                             server->cq_count * sizeof(grpc_completion_queue *));
@@ -1010,7 +1011,7 @@ void grpc_server_destroy(grpc_server *server) {
   listener *l;
 
   gpr_mu_lock(&server->mu);
-  GPR_ASSERT(server->shutdown);
+  GPR_ASSERT(server->shutdown || !server->listeners);
   GPR_ASSERT(server->listeners_destroyed == num_listeners(server));
 
   while (server->listeners) {
@@ -1081,6 +1082,9 @@ grpc_call_error grpc_server_request_call(
   GRPC_SERVER_LOG_REQUEST_CALL(GPR_INFO, server, call, details,
                                initial_metadata, cq_bound_to_call,
                                cq_for_notification, tag);
+  if (!grpc_cq_is_server_cq(cq_for_notification)) {
+    return GRPC_CALL_ERROR_NOT_SERVER_COMPLETION_QUEUE;
+  }
   grpc_cq_begin_op(cq_for_notification, NULL);
   rc.type = BATCH_CALL;
   rc.tag = tag;
@@ -1099,6 +1103,9 @@ grpc_call_error grpc_server_request_registered_call(
     grpc_completion_queue *cq_for_notification, void *tag) {
   requested_call rc;
   registered_method *registered_method = rm;
+  if (!grpc_cq_is_server_cq(cq_for_notification)) {
+    return GRPC_CALL_ERROR_NOT_SERVER_COMPLETION_QUEUE;
+  }
   grpc_cq_begin_op(cq_for_notification, NULL);
   rc.type = REGISTERED_CALL;
   rc.tag = tag;
@@ -1153,6 +1160,7 @@ static void begin_call(grpc_server *server, call_data *calld,
       rc->data.batch.details->deadline = calld->deadline;
       r->op = GRPC_IOREQ_RECV_INITIAL_METADATA;
       r->data.recv_metadata = rc->data.batch.initial_metadata;
+      r->flags = 0;
       r++;
       publish = publish_registered_or_batch;
       break;
@@ -1160,10 +1168,12 @@ static void begin_call(grpc_server *server, call_data *calld,
       *rc->data.registered.deadline = calld->deadline;
       r->op = GRPC_IOREQ_RECV_INITIAL_METADATA;
       r->data.recv_metadata = rc->data.registered.initial_metadata;
+      r->flags = 0;
       r++;
       if (rc->data.registered.optional_payload) {
         r->op = GRPC_IOREQ_RECV_MESSAGE;
         r->data.recv_message = rc->data.registered.optional_payload;
+        r->flags = 0;
         r++;
       }
       publish = publish_registered_or_batch;

src/core/transport/chttp2_transport.c

@@ -230,7 +230,10 @@ struct transport {
   /* basic state management - what are we doing at the moment? */
   gpr_uint8 reading;
   gpr_uint8 writing;
-  gpr_uint8 calling_back;
+  /** are we calling back (via cb) with a channel-level event */
+  gpr_uint8 calling_back_channel;
+  /** are we calling back any grpc_transport_op completion events */
+  gpr_uint8 calling_back_ops;
   gpr_uint8 destroying;
   gpr_uint8 closed;
   error_state error_state;
@@ -357,7 +360,7 @@ static void push_setting(transport *t, grpc_chttp2_setting_id id,
                          gpr_uint32 value);
 
 static int prepare_callbacks(transport *t);
-static void run_callbacks(transport *t, const grpc_transport_callbacks *cb);
+static void run_callbacks(transport *t);
 static void call_cb_closed(transport *t, const grpc_transport_callbacks *cb);
 
 static int prepare_write(transport *t);
@@ -565,7 +568,7 @@ static void init_transport(transport *t, grpc_transport_setup_callback setup,
   }
 
   gpr_mu_lock(&t->mu);
-  t->calling_back = 1;
+  t->calling_back_channel = 1;
   ref_transport(t); /* matches unref at end of this function */
   gpr_mu_unlock(&t->mu);
 
@@ -574,7 +577,7 @@ static void init_transport(transport *t, grpc_transport_setup_callback setup,
   lock(t);
   t->cb = sr.callbacks;
   t->cb_user_data = sr.user_data;
-  t->calling_back = 0;
+  t->calling_back_channel = 0;
   if (t->destroying) gpr_cv_signal(&t->cv);
   unlock(t);
 
@@ -595,7 +598,7 @@ static void destroy_transport(grpc_transport *gt) {
      We need to be not writing as cancellation finalization may produce some
      callbacks that NEED to be made to close out some streams when t->writing
      becomes 0. */
-  while (t->calling_back || t->writing) {
+  while (t->calling_back_channel || t->writing) {
     gpr_cv_wait(&t->cv, &t->mu, gpr_inf_future);
   }
   drop_connection(t);
@@ -835,28 +838,29 @@ static void unlock(transport *t) {
   finish_reads(t);
 
   /* gather any callbacks that need to be made */
-  if (!t->calling_back) {
-    t->calling_back = perform_callbacks = prepare_callbacks(t);
-    if (cb) {
-      if (t->error_state == ERROR_STATE_SEEN && !t->writing) {
-        call_closed = 1;
-        t->calling_back = 1;
-        t->cb = NULL; /* no more callbacks */
-        t->error_state = ERROR_STATE_NOTIFIED;
-      }
-      if (t->num_pending_goaways) {
-        goaways = t->pending_goaways;
-        num_goaways = t->num_pending_goaways;
-        t->pending_goaways = NULL;
-        t->num_pending_goaways = 0;
-        t->cap_pending_goaways = 0;
-        t->calling_back = 1;
-      }
-    }
+  if (!t->calling_back_ops) {
+    t->calling_back_ops = perform_callbacks = prepare_callbacks(t);
+    if (perform_callbacks) ref_transport(t);
   }
 
-  if (perform_callbacks || call_closed || num_goaways) {
-    ref_transport(t);
+  if (!t->calling_back_channel && cb) {
+    if (t->error_state == ERROR_STATE_SEEN && !t->writing) {
+      call_closed = 1;
+      t->calling_back_channel = 1;
+      t->cb = NULL; /* no more callbacks */
+      t->error_state = ERROR_STATE_NOTIFIED;
+    }
+    if (t->num_pending_goaways) {
+      goaways = t->pending_goaways;
+      num_goaways = t->num_pending_goaways;
+      t->pending_goaways = NULL;
+      t->num_pending_goaways = 0;
+      t->cap_pending_goaways = 0;
+      t->calling_back_channel = 1;
+    }
+    if (call_closed || num_goaways) {
+      ref_transport(t);
+    }
   }
 
   /* finally unlock */
@@ -870,7 +874,11 @@ static void unlock(transport *t) {
   }
 
   if (perform_callbacks) {
-    run_callbacks(t, cb);
+    run_callbacks(t);
+    lock(t);
+    t->calling_back_ops = 0;
+    unlock(t);
+    unref_transport(t);
   }
 
   if (call_closed) {
@@ -883,9 +891,9 @@ static void unlock(transport *t) {
     perform_write(t, ep);
   }
 
-  if (perform_callbacks || call_closed || num_goaways) {
+  if (call_closed || num_goaways) {
     lock(t);
-    t->calling_back = 0;
+    t->calling_back_channel = 0;
     if (t->destroying) gpr_cv_signal(&t->cv);
     unlock(t);
     unref_transport(t);
@@ -2121,7 +2129,7 @@ static int prepare_callbacks(transport *t) {
   return t->executing_callbacks.count > 0;
 }
 
-static void run_callbacks(transport *t, const grpc_transport_callbacks *cb) {
+static void run_callbacks(transport *t) {
   size_t i;
   for (i = 0; i < t->executing_callbacks.count; i++) {
     op_closure c = t->executing_callbacks.callbacks[i];

src/core/transport/metadata.c

@@ -120,7 +120,7 @@ static void unlock(grpc_mdctx *ctx) {
   if (ctx->refs == 0) {
     /* uncomment if you're having trouble diagnosing an mdelem leak to make
        things clearer (slows down destruction a lot, however) */
-    gc_mdtab(ctx);
+    /* gc_mdtab(ctx); */
     if (ctx->mdtab_count && ctx->mdtab_count == ctx->mdtab_free) {
       discard_metadata(ctx);
     }

src/core/transport/stream_op.h

@@ -58,11 +58,18 @@ typedef enum grpc_stream_op_code {
   GRPC_OP_SLICE
 } grpc_stream_op_code;
 
-/* Arguments for GRPC_OP_BEGIN */
+/** Internal bit flag for grpc_begin_message's \a flags signaling the use of
+ * compression for the message */
+#define GRPC_WRITE_INTERNAL_COMPRESS (0x80000000u)
+/** Mask of all valid internal flags. */
+#define GRPC_WRITE_INTERNAL_USED_MASK (GRPC_WRITE_INTERNAL_COMPRESS)
+
+/* Arguments for GRPC_OP_BEGIN_MESSAGE */
 typedef struct grpc_begin_message {
   /* How many bytes of data will this message contain */
   gpr_uint32 length;
-  /* Write flags for the message: see grpc.h GRPC_WRITE_xxx */
+  /* Write flags for the message: see grpc.h GRPC_WRITE_* for the public bits,
+   * GRPC_WRITE_INTERNAL_* for the internal ones. */
   gpr_uint32 flags;
 } grpc_begin_message;
 
@@ -126,10 +133,8 @@ typedef struct grpc_stream_op {
   } data;
 } grpc_stream_op;
 
-/* A stream op buffer is a wrapper around stream operations that is dynamically
-   extendable.
-   TODO(ctiller): inline a few elements into the struct, to avoid common case
-                  per-call allocations. */
+/** A stream op buffer is a wrapper around stream operations that is
+ * dynamically extendable. */
 typedef struct grpc_stream_op_buffer {
   grpc_stream_op *ops;
   size_t nops;

src/cpp/proto/proto_utils.cc

@@ -49,8 +49,8 @@ class GrpcBufferWriter GRPC_FINAL
   explicit GrpcBufferWriter(grpc_byte_buffer** bp,
                             int block_size = kMaxBufferLength)
       : block_size_(block_size), byte_count_(0), have_backup_(false) {
-    *bp = grpc_byte_buffer_create(NULL, 0);
-    slice_buffer_ = &(*bp)->data.slice_buffer;
+    *bp = grpc_raw_byte_buffer_create(NULL, 0);
+    slice_buffer_ = &(*bp)->data.raw.slice_buffer;
   }
 
   ~GrpcBufferWriter() GRPC_OVERRIDE {

src/cpp/util/byte_buffer.cc

@@ -42,7 +42,7 @@ ByteBuffer::ByteBuffer(Slice* slices, size_t nslices) {
   for (size_t i = 0; i < nslices; i++) {
     c_slices[i] = slices[i].slice_;
   }
-  buffer_ = grpc_byte_buffer_create(c_slices.data(), nslices);
+  buffer_ = grpc_raw_byte_buffer_create(c_slices.data(), nslices);
 }
 
 void ByteBuffer::Clear() {

src/cpp/util/status.cc

@@ -36,6 +36,6 @@
 namespace grpc {
 
 const Status& Status::OK = Status();
-const Status& Status::Cancelled = Status(StatusCode::CANCELLED);
+const Status& Status::CANCELLED = Status(StatusCode::CANCELLED, "");
 
 }  // namespace grpc

src/cpp/util/time.cc

@@ -42,6 +42,7 @@ using std::chrono::duration_cast;
 using std::chrono::nanoseconds;
 using std::chrono::seconds;
 using std::chrono::system_clock;
+using std::chrono::high_resolution_clock;
 
 namespace grpc {
 
@@ -59,6 +60,20 @@ void Timepoint2Timespec(const system_clock::time_point& from,
   to->tv_nsec = nsecs.count();
 }
 
+void TimepointHR2Timespec(const high_resolution_clock::time_point& from,
+                          gpr_timespec* to) {
+  high_resolution_clock::duration deadline = from.time_since_epoch();
+  seconds secs = duration_cast<seconds>(deadline);
+  if (from == high_resolution_clock::time_point::max() ||
+      secs.count() >= gpr_inf_future.tv_sec || secs.count() < 0) {
+    *to = gpr_inf_future;
+    return;
+  }
+  nanoseconds nsecs = duration_cast<nanoseconds>(deadline - secs);
+  to->tv_sec = secs.count();
+  to->tv_nsec = nsecs.count();
+}
+
 system_clock::time_point Timespec2Timepoint(gpr_timespec t) {
   if (gpr_time_cmp(t, gpr_inf_future) == 0) {
     return system_clock::time_point::max();

src/csharp/Grpc.Core.Tests/ChannelOptionsTest.cs

@@ -0,0 +1,105 @@
+#region Copyright notice and license
+
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#endregion
+
+using System;
+using System.Collections.Generic;
+using Grpc.Core;
+using Grpc.Core.Internal;
+using Grpc.Core.Utils;
+using NUnit.Framework;
+
+namespace Grpc.Core.Internal.Tests
+{
+    public class ChannelOptionsTest
+    {
+        [Test]
+        public void IntOption()
+        {
+            var option = new ChannelOption("somename", 1);
+
+            Assert.AreEqual(ChannelOption.OptionType.Integer, option.Type);
+            Assert.AreEqual("somename", option.Name);
+            Assert.AreEqual(1, option.IntValue);
+            Assert.Throws(typeof(InvalidOperationException), () => { var s = option.StringValue; });
+        }
+
+        [Test]
+        public void StringOption()
+        {
+            var option = new ChannelOption("somename", "ABCDEF");
+
+            Assert.AreEqual(ChannelOption.OptionType.String, option.Type);
+            Assert.AreEqual("somename", option.Name);
+            Assert.AreEqual("ABCDEF", option.StringValue);
+            Assert.Throws(typeof(InvalidOperationException), () => { var s = option.IntValue; });
+        }
+
+        [Test]
+        public void ConstructorPreconditions()
+        {
+            Assert.Throws(typeof(NullReferenceException), () => { new ChannelOption(null, "abc"); });
+            Assert.Throws(typeof(NullReferenceException), () => { new ChannelOption(null, 1); });
+            Assert.Throws(typeof(NullReferenceException), () => { new ChannelOption("abc", null); });
+        }
+
+        [Test]
+        public void CreateChannelArgsNull()
+        {
+            var channelArgs = ChannelOptions.CreateChannelArgs(null);
+            Assert.IsTrue(channelArgs.IsInvalid);
+        }
+
+        [Test]
+        public void CreateChannelArgsEmpty()
+        {
+            var options = new List<ChannelOption>();
+            var channelArgs = ChannelOptions.CreateChannelArgs(options);
+            channelArgs.Dispose();
+        }
+
+        [Test]
+        public void CreateChannelArgs()
+        {
+            var options = new List<ChannelOption>
+            {
+                new ChannelOption("ABC", "XYZ"),
+                new ChannelOption("somename", "IJKLM"),
+                new ChannelOption("intoption", 12345),
+                new ChannelOption("GHIJK", 12345),
+            };
+
+            var channelArgs = ChannelOptions.CreateChannelArgs(options);
+            channelArgs.Dispose();
+        }
+    }
+}

src/csharp/Grpc.Core.Tests/ClientServerTest.cs

@@ -86,7 +86,7 @@ namespace Grpc.Core.Tests
             server.AddServiceDefinition(ServiceDefinition);
             int port = server.AddListeningPort(Host, Server.PickUnusedPort);
             server.Start();
-            channel = new Channel(Host + ":" + port);
+            channel = new Channel(Host, port);
         }
 
         [TearDown]

src/csharp/Grpc.Core.Tests/Grpc.Core.Tests.csproj

@@ -3,8 +3,6 @@
   <PropertyGroup>
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
     <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
-    <ProductVersion>10.0.0</ProductVersion>
-    <SchemaVersion>2.0</SchemaVersion>
     <ProjectGuid>{86EC5CB4-4EA2-40A2-8057-86542A0353BB}</ProjectGuid>
     <OutputType>Library</OutputType>
     <RootNamespace>Grpc.Core.Tests</RootNamespace>
@@ -46,6 +44,10 @@
     <Compile Include="TimespecTest.cs" />
     <Compile Include="PInvokeTest.cs" />
     <Compile Include="Internal\MetadataArraySafeHandleTest.cs" />
+    <Compile Include="Internal\CompletionQueueSafeHandleTest.cs" />
+    <Compile Include="Internal\CompletionQueueEventTest.cs" />
+    <Compile Include="Internal\ChannelArgsSafeHandleTest.cs" />
+    <Compile Include="ChannelOptionsTest.cs" />
   </ItemGroup>
   <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
   <ItemGroup>
@@ -61,4 +63,4 @@
     <Service Include="{82A7F48D-3B50-4B1E-B82E-3ADA8210C358}" />
   </ItemGroup>
   <ItemGroup />
-</Project>
+</Project>

src/csharp/Grpc.Core.Tests/Internal/ChannelArgsSafeHandleTest.cs

@@ -0,0 +1,75 @@
+#region Copyright notice and license
+
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#endregion
+
+using System;
+using Grpc.Core;
+using Grpc.Core.Internal;
+using Grpc.Core.Utils;
+using NUnit.Framework;
+
+namespace Grpc.Core.Internal.Tests
+{
+    public class ChannelArgsSafeHandleTest
+    {
+        [Test]
+        public void CreateEmptyAndDestroy()
+        {
+            var channelArgs = ChannelArgsSafeHandle.Create(0);
+            channelArgs.Dispose();
+        }
+
+        [Test]
+        public void CreateNonEmptyAndDestroy()
+        {
+            var channelArgs = ChannelArgsSafeHandle.Create(5);
+            channelArgs.Dispose();
+        }
+
+        [Test]
+        public void CreateNullAndDestroy()
+        {
+            var channelArgs = ChannelArgsSafeHandle.CreateNull();
+            channelArgs.Dispose();
+        }
+
+        [Test]
+        public void CreateFillAndDestroy()
+        {
+            var channelArgs = ChannelArgsSafeHandle.Create(3);
+            channelArgs.SetInteger(0, "somekey", 12345);
+            channelArgs.SetString(1, "somekey", "abcdefghijkl");
+            channelArgs.SetString(2, "somekey", "XYZ");
+            channelArgs.Dispose();
+        }
+    }
+}

src/csharp/Grpc.Core.Tests/Internal/CompletionQueueEventTest.cs

@@ -0,0 +1,52 @@
+#region Copyright notice and license
+
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#endregion
+
+using System;
+using System.Runtime.InteropServices;
+using System.Threading.Tasks;
+using Grpc.Core;
+using Grpc.Core.Internal;
+using Grpc.Core.Utils;
+using NUnit.Framework;
+
+namespace Grpc.Core.Internal.Tests
+{
+    public class CompletionQueueEventTest
+    {
+        [Test]
+        public void CreateAndDestroy()
+        {
+            Assert.AreEqual(CompletionQueueEvent.NativeSize, Marshal.SizeOf(typeof(CompletionQueueEvent)));
+        }
+    }
+}

src/csharp/Grpc.Core.Tests/Internal/CompletionQueueSafeHandleTest.cs

@@ -0,0 +1,64 @@
+#region Copyright notice and license
+
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#endregion
+
+using System;
+using System.Threading.Tasks;
+using Grpc.Core;
+using Grpc.Core.Internal;
+using Grpc.Core.Utils;
+using NUnit.Framework;
+
+namespace Grpc.Core.Internal.Tests
+{
+    public class CompletionQueueSafeHandleTest
+    {
+        [Test]
+        public void CreateAndDestroy()
+        {
+            var cq = CompletionQueueSafeHandle.Create();
+            cq.Dispose();
+        }
+
+        [Test]
+        public void CreateAndShutdown()
+        {
+            var cq = CompletionQueueSafeHandle.Create();
+            cq.Shutdown();
+            var ev = cq.Next();
+            cq.Dispose();
+            Assert.AreEqual(GRPCCompletionType.Shutdown, ev.type);
+            Assert.AreNotEqual(IntPtr.Zero, ev.success);
+            Assert.AreEqual(IntPtr.Zero, ev.tag);
+        }
+    }
+}

src/csharp/Grpc.Core.Tests/PInvokeTest.cs

@@ -48,7 +48,7 @@ namespace Grpc.Core.Tests
         int counter;
 
         [DllImport("grpc_csharp_ext.dll")]
-        static extern GRPCCallError grpcsharp_test_callback([MarshalAs(UnmanagedType.FunctionPtr)] CompletionCallbackDelegate callback);
+        static extern GRPCCallError grpcsharp_test_callback([MarshalAs(UnmanagedType.FunctionPtr)] OpCompletionDelegate callback);
 
         [DllImport("grpc_csharp_ext.dll")]
         static extern IntPtr grpcsharp_test_nop(IntPtr ptr);
@@ -88,7 +88,7 @@ namespace Grpc.Core.Tests
         [Test]
         public void NativeCallbackBenchmark()
         {
-            CompletionCallbackDelegate handler = Handler;
+            OpCompletionDelegate handler = Handler;
 
             counter = 0;
             BenchmarkUtil.RunBenchmark(
@@ -114,7 +114,7 @@ namespace Grpc.Core.Tests
                 10000, 10000,
                 () =>
                 {
-                    grpcsharp_test_callback(new CompletionCallbackDelegate(Handler));
+                    grpcsharp_test_callback(new OpCompletionDelegate(Handler));
                 });
             Assert.AreNotEqual(0, counter);
         }
@@ -134,7 +134,7 @@ namespace Grpc.Core.Tests
                 });
         }
 
-        private void Handler(bool success, IntPtr ptr)
+        private void Handler(bool success)
         {
             counter++;
         }

src/csharp/Grpc.Core/Channel.cs

@@ -29,6 +29,7 @@
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #endregion
 using System;
+using System.Collections.Generic;
 using System.Runtime.InteropServices;
 using System.Threading;
 using System.Threading.Tasks;
@@ -45,33 +46,41 @@ namespace Grpc.Core
         readonly string target;
 
         /// <summary>
-        /// Creates a channel.
+        /// Creates a channel that connects to a specific host.
+        /// Port will default to 80 for an unsecure channel and to 443 a secure channel.
         /// </summary>
-        public Channel(string target, Credentials credentials = null, ChannelArgs channelArgs = null)
+        /// <param name="host">The DNS name of IP address of the host.</param>
+        /// <param name="credentials">Optional credentials to create a secure channel.</param>
+        /// <param name="options">Channel options.</param>
+        public Channel(string host, Credentials credentials = null, IEnumerable<ChannelOption> options = null)
         {
-            using (ChannelArgsSafeHandle nativeChannelArgs = CreateNativeChannelArgs(channelArgs))
+            using (ChannelArgsSafeHandle nativeChannelArgs = ChannelOptions.CreateChannelArgs(options))
             {
                 if (credentials != null)
                 {
                     using (CredentialsSafeHandle nativeCredentials = credentials.ToNativeCredentials())
                     {
-                        this.handle = ChannelSafeHandle.CreateSecure(nativeCredentials, target, nativeChannelArgs);
+                        this.handle = ChannelSafeHandle.CreateSecure(nativeCredentials, host, nativeChannelArgs);
                     }
                 }
                 else
                 {
-                    this.handle = ChannelSafeHandle.Create(target, nativeChannelArgs);
+                    this.handle = ChannelSafeHandle.Create(host, nativeChannelArgs);
                 }
             }
-            this.target = GetOverridenTarget(target, channelArgs);
+            this.target = GetOverridenTarget(host, options);
         }
 
-        public string Target
+        /// <summary>
+        /// Creates a channel that connects to a specific host and port.
+        /// </summary>
+        /// <param name="host">DNS name or IP address</param>
+        /// <param name="port">the port</param>
+        /// <param name="credentials">Optional credentials to create a secure channel.</param>
+        /// <param name="options">Channel options.</param>
+        public Channel(string host, int port, Credentials credentials = null, IEnumerable<ChannelOption> options = null) :
+            this(string.Format("{0}:{1}", host, port), credentials, options)
         {
-            get
-            {
-                return this.target;
-            }
         }
 
         public void Dispose()
@@ -80,6 +89,14 @@ namespace Grpc.Core
             GC.SuppressFinalize(this);
         }
 
+        internal string Target
+        {
+            get
+            {
+                return target;
+            }
+        }
+
         internal ChannelSafeHandle Handle
         {
             get
@@ -96,22 +113,25 @@ namespace Grpc.Core
             }
         }
 
-        private static string GetOverridenTarget(string target, ChannelArgs args)
+        /// <summary>
+        /// Look for SslTargetNameOverride option and return its value instead of originalTarget
+        /// if found.
+        /// </summary>
+        private static string GetOverridenTarget(string originalTarget, IEnumerable<ChannelOption> options)
         {
-            if (args != null && !string.IsNullOrEmpty(args.GetSslTargetNameOverride()))
+            if (options == null)
             {
-                return args.GetSslTargetNameOverride();
+                return originalTarget;
             }
-            return target;
-        }
-
-        private static ChannelArgsSafeHandle CreateNativeChannelArgs(ChannelArgs args)
-        {
-            if (args == null)
+            foreach (var option in options)
             {
-                return ChannelArgsSafeHandle.CreateNull();
+                if (option.Type == ChannelOption.OptionType.String
+                    && option.Name == ChannelOptions.SslTargetNameOverride)
+                {
+                    return option.StringValue;
+                }
             }
-            return args.ToNativeChannelArgs();
+            return originalTarget;
         }
     }
 }

src/csharp/Grpc.Core/ChannelArgs.cs

@@ -1,115 +0,0 @@
-#region Copyright notice and license
-// Copyright 2015, Google Inc.
-// All rights reserved.
-//
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are
-// met:
-//
-//     * Redistributions of source code must retain the above copyright
-// notice, this list of conditions and the following disclaimer.
-//     * Redistributions in binary form must reproduce the above
-// copyright notice, this list of conditions and the following disclaimer
-// in the documentation and/or other materials provided with the
-// distribution.
-//     * Neither the name of Google Inc. nor the names of its
-// contributors may be used to endorse or promote products derived from
-// this software without specific prior written permission.
-//
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-#endregion
-using System;
-using System.Collections.Generic;
-using System.Collections.Immutable;
-using System.Runtime.InteropServices;
-using System.Threading;
-using System.Threading.Tasks;
-using Grpc.Core.Internal;
-
-namespace Grpc.Core
-{
-    /// <summary>
-    /// gRPC channel options.
-    /// </summary>
-    public class ChannelArgs
-    {
-        public const string SslTargetNameOverrideKey = "grpc.ssl_target_name_override";
-
-        readonly ImmutableDictionary<string, string> stringArgs;
-
-        private ChannelArgs(ImmutableDictionary<string, string> stringArgs)
-        {
-            this.stringArgs = stringArgs;
-        }
-
-        public string GetSslTargetNameOverride()
-        {
-            string result;
-            if (stringArgs.TryGetValue(SslTargetNameOverrideKey, out result))
-            {
-                return result;
-            }
-            return null;
-        }
-
-        public static Builder CreateBuilder()
-        {
-            return new Builder();
-        }
-
-        public class Builder
-        {
-            readonly Dictionary<string, string> stringArgs = new Dictionary<string, string>();
-
-            // TODO: AddInteger not supported yet.
-            public Builder AddString(string key, string value)
-            {
-                stringArgs.Add(key, value);
-                return this;
-            }
-
-            public ChannelArgs Build()
-            {
-                return new ChannelArgs(stringArgs.ToImmutableDictionary());
-            }
-        }
-
-        /// <summary>
-        /// Creates native object for the channel arguments.
-        /// </summary>
-        /// <returns>The native channel arguments.</returns>
-        internal ChannelArgsSafeHandle ToNativeChannelArgs()
-        {
-            ChannelArgsSafeHandle nativeArgs = null;
-            try
-            {
-                nativeArgs = ChannelArgsSafeHandle.Create(stringArgs.Count);
-                int i = 0;
-                foreach (var entry in stringArgs)
-                {
-                    nativeArgs.SetString(i, entry.Key, entry.Value);
-                    i++;
-                }
-                return nativeArgs;
-            }
-            catch (Exception)
-            {
-                if (nativeArgs != null)
-                {
-                    nativeArgs.Dispose();
-                }
-                throw;
-            }
-        }
-    }
-}

src/csharp/Grpc.Core/ChannelOptions.cs

@@ -0,0 +1,178 @@
+#region Copyright notice and license
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#endregion
+using System;
+using System.Collections.Generic;
+using System.Collections.Immutable;
+using System.Runtime.InteropServices;
+using System.Threading;
+using System.Threading.Tasks;
+using Grpc.Core.Internal;
+using Grpc.Core.Utils;
+
+namespace Grpc.Core
+{
+    /// <summary>
+    /// Channel option specified when creating a channel.
+    /// Corresponds to grpc_channel_args from grpc/grpc.h.
+    /// </summary>
+    public sealed class ChannelOption
+    {
+        public enum OptionType
+        {
+            Integer,
+            String
+        }
+
+        private readonly OptionType type;
+        private readonly string name;
+        private readonly int intValue;
+        private readonly string stringValue;
+
+        /// <summary>
+        /// Creates a channel option with a string value.
+        /// </summary>
+        /// <param name="name">Name.</param>
+        /// <param name="stringValue">String value.</param>
+        public ChannelOption(string name, string stringValue)
+        {
+            this.type = OptionType.String;
+            this.name = Preconditions.CheckNotNull(name);
+            this.stringValue = Preconditions.CheckNotNull(stringValue);
+        }
+
+        /// <summary>
+        /// Creates a channel option with an integer value.
+        /// </summary>
+        /// <param name="name">Name.</param>
+        /// <param name="stringValue">String value.</param>
+        public ChannelOption(string name, int intValue)
+        {
+            this.type = OptionType.Integer;
+            this.name = Preconditions.CheckNotNull(name);
+            this.intValue = intValue;
+        }
+
+        public OptionType Type
+        {
+            get
+            {
+                return type;
+            }
+        }
+
+        public string Name
+        {
+            get
+            {
+                return name;
+            }    
+        }
+
+        public int IntValue
+        {
+            get
+            {
+                Preconditions.CheckState(type == OptionType.Integer);
+                return intValue;
+            }
+        }
+
+        public string StringValue
+        {
+            get
+            {
+                Preconditions.CheckState(type == OptionType.String);
+                return stringValue;
+            }
+        }
+    }
+
+    public static class ChannelOptions
+    {
+        // Override SSL target check. Only to be used for testing.
+        public const string SslTargetNameOverride = "grpc.ssl_target_name_override";
+
+        // Enable census for tracing and stats collection
+        public const string Census = "grpc.census";
+
+        // Maximum number of concurrent incoming streams to allow on a http2 connection
+        public const string MaxConcurrentStreams = "grpc.max_concurrent_streams";
+
+        // Maximum message length that the channel can receive
+        public const string MaxMessageLength = "grpc.max_message_length";
+
+        // Initial sequence number for http2 transports
+        public const string Http2InitialSequenceNumber = "grpc.http2.initial_sequence_number";
+
+        /// <summary>
+        /// Creates native object for a collection of channel options.
+        /// </summary>
+        /// <returns>The native channel arguments.</returns>
+        internal static ChannelArgsSafeHandle CreateChannelArgs(IEnumerable<ChannelOption> options)
+        {
+            if (options == null)
+            {
+                return ChannelArgsSafeHandle.CreateNull();
+            }
+            var optionList = new List<ChannelOption>(options);  // It's better to do defensive copy
+            ChannelArgsSafeHandle nativeArgs = null;
+            try
+            {
+                nativeArgs = ChannelArgsSafeHandle.Create(optionList.Count);
+                for (int i = 0; i < optionList.Count; i++)
+                {
+                    var option = optionList[i];
+                    if (option.Type == ChannelOption.OptionType.Integer)
+                    {
+                        nativeArgs.SetInteger(i, option.Name, option.IntValue);
+                    }
+                    else if (option.Type == ChannelOption.OptionType.String)
+                    {
+                        nativeArgs.SetString(i, option.Name, option.StringValue);
+                    }
+                    else 
+                    {
+                        throw new InvalidOperationException("Unknown option type");
+                    }
+                }
+                return nativeArgs;
+            }
+            catch (Exception)
+            {
+                if (nativeArgs != null)
+                {
+                    nativeArgs.Dispose();
+                }
+                throw;
+            }
+        }
+    }
+}

src/csharp/Grpc.Core/Grpc.Core.csproj

@@ -5,8 +5,6 @@
   <PropertyGroup>
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
     <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
-    <ProductVersion>8.0.30703</ProductVersion>
-    <SchemaVersion>2.0</SchemaVersion>
     <ProjectGuid>{CCC4440E-49F7-4790-B0AF-FEABB0837AE7}</ProjectGuid>
     <OutputType>Library</OutputType>
     <RootNamespace>Grpc.Core</RootNamespace>
@@ -73,13 +71,11 @@
     <Compile Include="Marshaller.cs" />
     <Compile Include="ServerServiceDefinition.cs" />
     <Compile Include="Utils\AsyncStreamExtensions.cs" />
-    <Compile Include="Internal\BatchContextSafeHandleNotOwned.cs" />
     <Compile Include="Utils\BenchmarkUtil.cs" />
     <Compile Include="Utils\ExceptionHelper.cs" />
     <Compile Include="Internal\CredentialsSafeHandle.cs" />
     <Compile Include="Credentials.cs" />
     <Compile Include="Internal\ChannelArgsSafeHandle.cs" />
-    <Compile Include="ChannelArgs.cs" />
     <Compile Include="Internal\AsyncCompletion.cs" />
     <Compile Include="Internal\AsyncCallBase.cs" />
     <Compile Include="Internal\AsyncCallServer.cs" />
@@ -101,6 +97,10 @@
     <Compile Include="Internal\AtomicCounter.cs" />
     <Compile Include="Internal\DebugStats.cs" />
     <Compile Include="ServerCallContext.cs" />
+    <Compile Include="Internal\CompletionQueueEvent.cs" />
+    <Compile Include="Internal\CompletionRegistry.cs" />
+    <Compile Include="Internal\BatchContextSafeHandle.cs" />
+    <Compile Include="ChannelOptions.cs" />
   </ItemGroup>
   <ItemGroup>
     <None Include="packages.config" />
@@ -130,4 +130,4 @@
   </Target>
   <Import Project="..\packages\grpc.dependencies.openssl.redist.1.0.2.2\build\portable-net45\grpc.dependencies.openssl.redist.targets" Condition="Exists('..\packages\grpc.dependencies.openssl.redist.1.0.2.2\build\portable-net45\grpc.dependencies.openssl.redist.targets')" />
   <Import Project="..\packages\grpc.dependencies.zlib.redist.1.2.8.9\build\portable-net45\grpc.dependencies.zlib.redist.targets" Condition="Exists('..\packages\grpc.dependencies.zlib.redist.1.2.8.9\build\portable-net45\grpc.dependencies.zlib.redist.targets')" />
-</Project>
+</Project>

src/csharp/Grpc.Core/GrpcEnvironment.cs

@@ -54,6 +54,7 @@ namespace Grpc.Core
         static volatile GrpcEnvironment instance;
 
         readonly GrpcThreadPool threadPool;
+        readonly CompletionRegistry completionRegistry;
         bool isClosed;
 
         /// <summary>
@@ -105,6 +106,19 @@ namespace Grpc.Core
             }
         }
 
+        internal static CompletionRegistry CompletionRegistry
+        {
+            get
+            {
+                var inst = instance;
+                if (inst == null)
+                {
+                    throw new InvalidOperationException("GRPC environment not initialized");
+                }
+                return inst.completionRegistry;
+            }
+        }
+
         /// <summary>
         /// Creates gRPC environment.
         /// </summary>
@@ -112,6 +126,7 @@ namespace Grpc.Core
         {
             GrpcLog.RedirectNativeLogs(Console.Error);
             grpcsharp_init();
+            completionRegistry = new CompletionRegistry();
             threadPool = new GrpcThreadPool(THREAD_POOL_SIZE);
             threadPool.Start();
             // TODO: use proper logging here
@@ -139,14 +154,24 @@ namespace Grpc.Core
         {
             var remainingClientCalls = DebugStats.ActiveClientCalls.Count;
             if (remainingClientCalls != 0)
-            {
-                Console.WriteLine("Warning: Detected {0} client calls that weren't disposed properly.", remainingClientCalls);
+            {                
+                DebugWarning(string.Format("Detected {0} client calls that weren't disposed properly.", remainingClientCalls));
             }
             var remainingServerCalls = DebugStats.ActiveServerCalls.Count;
             if (remainingServerCalls != 0)
             {
-                Console.WriteLine("Warning: Detected {0} server calls that weren't disposed properly.", remainingServerCalls);
+                DebugWarning(string.Format("Detected {0} server calls that weren't disposed properly.", remainingServerCalls));
+            }
+            var pendingBatchCompletions = DebugStats.PendingBatchCompletions.Count;
+            if (pendingBatchCompletions != 0)
+            {
+                DebugWarning(string.Format("Detected {0} pending batch completions.", pendingBatchCompletions));
             }
         }
+
+        private static void DebugWarning(string message)
+        {
+            throw new Exception("Shutdown check: " + message);
+        }
     }
 }

src/csharp/Grpc.Core/Internal/AsyncCall.cs

@@ -47,9 +47,6 @@ namespace Grpc.Core.Internal
     /// </summary>
     internal class AsyncCall<TRequest, TResponse> : AsyncCallBase<TRequest, TResponse>
     {
-        readonly CompletionCallbackDelegate unaryResponseHandler;
-        readonly CompletionCallbackDelegate finishedHandler;
-
         // Completion of a pending unary response if not null.
         TaskCompletionSource<TResponse> unaryResponseTcs;
 
@@ -60,8 +57,6 @@ namespace Grpc.Core.Internal
 
         public AsyncCall(Func<TRequest, byte[]> serializer, Func<byte[], TResponse> deserializer) : base(serializer, deserializer)
         {
-            this.unaryResponseHandler = CreateBatchCompletionCallback(HandleUnaryResponse);
-            this.finishedHandler = CreateBatchCompletionCallback(HandleFinished);
         }
 
         public void Initialize(Channel channel, CompletionQueueSafeHandle cq, string methodName)
@@ -96,7 +91,21 @@ namespace Grpc.Core.Internal
 
                 using (var metadataArray = MetadataArraySafeHandle.Create(headers))
                 {
-                    call.BlockingUnary(cq, payload, unaryResponseHandler, metadataArray);
+                    using (var ctx = BatchContextSafeHandle.Create())
+                    {
+                        call.StartUnary(payload, ctx, metadataArray);
+                        var ev = cq.Pluck(ctx.Handle);
+
+                        bool success = (ev.success != 0);
+                        try
+                        {
+                            HandleUnaryResponse(success, ctx);
+                        }
+                        catch (Exception e)
+                        {
+                            Console.WriteLine("Exception occured while invoking completion delegate: " + e);
+                        }
+                    }
                 }
 
                 try
@@ -129,7 +138,7 @@ namespace Grpc.Core.Internal
                 unaryResponseTcs = new TaskCompletionSource<TResponse>();
                 using (var metadataArray = MetadataArraySafeHandle.Create(headers))
                 {
-                    call.StartUnary(payload, unaryResponseHandler, metadataArray);
+                    call.StartUnary(payload, HandleUnaryResponse, metadataArray);
                 }
                 return unaryResponseTcs.Task;
             }
@@ -151,7 +160,7 @@ namespace Grpc.Core.Internal
                 unaryResponseTcs = new TaskCompletionSource<TResponse>();
                 using (var metadataArray = MetadataArraySafeHandle.Create(headers))
                 {
-                    call.StartClientStreaming(unaryResponseHandler, metadataArray);
+                    call.StartClientStreaming(HandleUnaryResponse, metadataArray);
                 }
 
                 return unaryResponseTcs.Task;
@@ -175,7 +184,7 @@ namespace Grpc.Core.Internal
 
                 using (var metadataArray = MetadataArraySafeHandle.Create(headers))
                 {
-                    call.StartServerStreaming(payload, finishedHandler, metadataArray);
+                    call.StartServerStreaming(payload, HandleFinished, metadataArray);
                 }
             }
         }
@@ -194,7 +203,7 @@ namespace Grpc.Core.Internal
 
                 using (var metadataArray = MetadataArraySafeHandle.Create(headers))
                 {
-                    call.StartDuplexStreaming(finishedHandler, metadataArray);
+                    call.StartDuplexStreaming(HandleFinished, metadataArray);
                 }
             }
         }
@@ -229,7 +238,7 @@ namespace Grpc.Core.Internal
                 Preconditions.CheckNotNull(completionDelegate, "Completion delegate cannot be null");
                 CheckSendingAllowed();
 
-                call.StartSendCloseFromClient(halfclosedHandler);
+                call.StartSendCloseFromClient(HandleHalfclosed);
 
                 halfcloseRequested = true;
                 sendCompletionDelegate = completionDelegate;
@@ -274,7 +283,7 @@ namespace Grpc.Core.Internal
         /// <summary>
         /// Handler for unary response completion.
         /// </summary>
-        private void HandleUnaryResponse(bool success, BatchContextSafeHandleNotOwned ctx)
+        private void HandleUnaryResponse(bool success, BatchContextSafeHandle ctx)
         {
             lock (myLock)
             {
@@ -307,7 +316,7 @@ namespace Grpc.Core.Internal
         /// <summary>
         /// Handles receive status completion for calls with streaming response.
         /// </summary>
-        private void HandleFinished(bool success, BatchContextSafeHandleNotOwned ctx)
+        private void HandleFinished(bool success, BatchContextSafeHandle ctx)
         {
             var status = ctx.GetReceivedStatus();
 

src/csharp/Grpc.Core/Internal/AsyncCallBase.cs

@@ -51,13 +51,8 @@ namespace Grpc.Core.Internal
         readonly Func<TWrite, byte[]> serializer;
         readonly Func<byte[], TRead> deserializer;
 
-        protected readonly CompletionCallbackDelegate sendFinishedHandler;
-        protected readonly CompletionCallbackDelegate readFinishedHandler;
-        protected readonly CompletionCallbackDelegate halfclosedHandler;
-
         protected readonly object myLock = new object();
 
-        protected GCHandle gchandle;
         protected CallSafeHandle call;
         protected bool disposed;
 
@@ -77,10 +72,6 @@ namespace Grpc.Core.Internal
         {
             this.serializer = Preconditions.CheckNotNull(serializer);
             this.deserializer = Preconditions.CheckNotNull(deserializer);
-  
-            this.sendFinishedHandler = CreateBatchCompletionCallback(HandleSendFinished);
-            this.readFinishedHandler = CreateBatchCompletionCallback(HandleReadFinished);
-            this.halfclosedHandler = CreateBatchCompletionCallback(HandleHalfclosed);
         }
 
         /// <summary>
@@ -121,9 +112,6 @@ namespace Grpc.Core.Internal
         {
             lock (myLock)
             {
-                // Make sure this object and the delegated held by it will not be garbage collected
-                // before we release this handle.
-                gchandle = GCHandle.Alloc(this);
                 this.call = call;
             }
         }
@@ -141,7 +129,7 @@ namespace Grpc.Core.Internal
                 Preconditions.CheckNotNull(completionDelegate, "Completion delegate cannot be null");
                 CheckSendingAllowed();
 
-                call.StartSendMessage(payload, sendFinishedHandler);
+                call.StartSendMessage(payload, HandleSendFinished);
                 sendCompletionDelegate = completionDelegate;
             }
         }
@@ -157,7 +145,7 @@ namespace Grpc.Core.Internal
                 Preconditions.CheckNotNull(completionDelegate, "Completion delegate cannot be null");
                 CheckReadingAllowed();
 
-                call.StartReceiveMessage(readFinishedHandler);
+                call.StartReceiveMessage(HandleReadFinished);
                 readCompletionDelegate = completionDelegate;
             }
         }
@@ -197,7 +185,6 @@ namespace Grpc.Core.Internal
             {
                 call.Dispose();
             }
-            gchandle.Free();
             disposed = true;
         }
 
@@ -281,30 +268,10 @@ namespace Grpc.Core.Internal
             }
         }
 
-        /// <summary>
-        /// Creates completion callback delegate that wraps the batch completion handler in a try catch block to
-        /// prevent propagating exceptions accross managed/unmanaged boundary.
-        /// </summary>
-        protected CompletionCallbackDelegate CreateBatchCompletionCallback(Action<bool, BatchContextSafeHandleNotOwned> handler)
-        {
-            return new CompletionCallbackDelegate((success, batchContextPtr) =>
-            {
-                try
-                {
-                    var ctx = new BatchContextSafeHandleNotOwned(batchContextPtr);
-                    handler(success, ctx);
-                }
-                catch (Exception e)
-                {
-                    Console.WriteLine("Caught exception in a native handler: " + e);
-                }
-            });
-        }
-
         /// <summary>
         /// Handles send completion.
         /// </summary>
-        private void HandleSendFinished(bool success, BatchContextSafeHandleNotOwned ctx)
+        protected void HandleSendFinished(bool success, BatchContextSafeHandle ctx)
         {
             AsyncCompletionDelegate<object> origCompletionDelegate = null;
             lock (myLock)
@@ -328,7 +295,7 @@ namespace Grpc.Core.Internal
         /// <summary>
         /// Handles halfclose completion.
         /// </summary>
-        private void HandleHalfclosed(bool success, BatchContextSafeHandleNotOwned ctx)
+        protected void HandleHalfclosed(bool success, BatchContextSafeHandle ctx)
         {
             AsyncCompletionDelegate<object> origCompletionDelegate = null;
             lock (myLock)
@@ -353,7 +320,7 @@ namespace Grpc.Core.Internal
         /// <summary>
         /// Handles streaming read completion.
         /// </summary>
-        private void HandleReadFinished(bool success, BatchContextSafeHandleNotOwned ctx)
+        protected void HandleReadFinished(bool success, BatchContextSafeHandle ctx)
         {
             var payload = ctx.GetReceivedMessage();
 

src/csharp/Grpc.Core/Internal/AsyncCallServer.cs

@@ -47,12 +47,10 @@ namespace Grpc.Core.Internal
     /// </summary>
     internal class AsyncCallServer<TRequest, TResponse> : AsyncCallBase<TResponse, TRequest>
     {
-        readonly CompletionCallbackDelegate finishedServersideHandler;
         readonly TaskCompletionSource<object> finishedServersideTcs = new TaskCompletionSource<object>();
 
         public AsyncCallServer(Func<TResponse, byte[]> serializer, Func<byte[], TRequest> deserializer) : base(serializer, deserializer)
         {
-            this.finishedServersideHandler = CreateBatchCompletionCallback(HandleFinishedServerside);
         }
 
         public void Initialize(CallSafeHandle call)
@@ -72,7 +70,7 @@ namespace Grpc.Core.Internal
 
                 started = true;
 
-                call.StartServerSide(finishedServersideHandler);
+                call.StartServerSide(HandleFinishedServerside);
                 return finishedServersideTcs.Task;
             }
         }
@@ -107,8 +105,9 @@ namespace Grpc.Core.Internal
                 Preconditions.CheckNotNull(completionDelegate, "Completion delegate cannot be null");
                 CheckSendingAllowed();
 
-                call.StartSendStatusFromServer(status, halfclosedHandler);
+                call.StartSendStatusFromServer(status, HandleHalfclosed);
                 halfcloseRequested = true;
+                readingDone = true;
                 sendCompletionDelegate = completionDelegate;
             }
         }
@@ -121,7 +120,7 @@ namespace Grpc.Core.Internal
         /// <summary>
         /// Handles the server side close completion.
         /// </summary>
-        private void HandleFinishedServerside(bool success, BatchContextSafeHandleNotOwned ctx)
+        private void HandleFinishedServerside(bool success, BatchContextSafeHandle ctx)
         {
             bool cancelled = ctx.GetReceivedCloseOnServerCancelled();
 

src/csharp/Grpc.Core/Internal/BatchContextSafeHandleNotOwned.cs → src/csharp/Grpc.Core/Internal/BatchContextSafeHandle.cs

@@ -41,32 +41,50 @@ namespace Grpc.Core.Internal
     /// Not owned version of 
     /// grpcsharp_batch_context
     /// </summary>
-    internal class BatchContextSafeHandleNotOwned : SafeHandleZeroIsInvalid
+    internal class BatchContextSafeHandle : SafeHandleZeroIsInvalid
     {
         [DllImport("grpc_csharp_ext.dll")]
-        static extern IntPtr grpcsharp_batch_context_recv_message_length(BatchContextSafeHandleNotOwned ctx);
+        static extern BatchContextSafeHandle grpcsharp_batch_context_create();
 
         [DllImport("grpc_csharp_ext.dll")]
-        static extern void grpcsharp_batch_context_recv_message_to_buffer(BatchContextSafeHandleNotOwned ctx, byte[] buffer, UIntPtr bufferLen);
+        static extern IntPtr grpcsharp_batch_context_recv_message_length(BatchContextSafeHandle ctx);
 
         [DllImport("grpc_csharp_ext.dll")]
-        static extern StatusCode grpcsharp_batch_context_recv_status_on_client_status(BatchContextSafeHandleNotOwned ctx);
+        static extern void grpcsharp_batch_context_recv_message_to_buffer(BatchContextSafeHandle ctx, byte[] buffer, UIntPtr bufferLen);
 
         [DllImport("grpc_csharp_ext.dll")]
-        static extern IntPtr grpcsharp_batch_context_recv_status_on_client_details(BatchContextSafeHandleNotOwned ctx);  // returns const char*
+        static extern StatusCode grpcsharp_batch_context_recv_status_on_client_status(BatchContextSafeHandle ctx);
 
         [DllImport("grpc_csharp_ext.dll")]
-        static extern CallSafeHandle grpcsharp_batch_context_server_rpc_new_call(BatchContextSafeHandleNotOwned ctx);
+        static extern IntPtr grpcsharp_batch_context_recv_status_on_client_details(BatchContextSafeHandle ctx);  // returns const char*
 
         [DllImport("grpc_csharp_ext.dll")]
-        static extern IntPtr grpcsharp_batch_context_server_rpc_new_method(BatchContextSafeHandleNotOwned ctx);  // returns const char*
+        static extern CallSafeHandle grpcsharp_batch_context_server_rpc_new_call(BatchContextSafeHandle ctx);
 
         [DllImport("grpc_csharp_ext.dll")]
-        static extern int grpcsharp_batch_context_recv_close_on_server_cancelled(BatchContextSafeHandleNotOwned ctx);
+        static extern IntPtr grpcsharp_batch_context_server_rpc_new_method(BatchContextSafeHandle ctx);  // returns const char*
 
-        public BatchContextSafeHandleNotOwned(IntPtr handle) : base(false)
+        [DllImport("grpc_csharp_ext.dll")]
+        static extern int grpcsharp_batch_context_recv_close_on_server_cancelled(BatchContextSafeHandle ctx);
+
+        [DllImport("grpc_csharp_ext.dll")]
+        static extern void grpcsharp_batch_context_destroy(IntPtr ctx);
+
+        private BatchContextSafeHandle()
+        {
+        }
+
+        public static BatchContextSafeHandle Create()
         {
-            SetHandle(handle);
+            return grpcsharp_batch_context_create();
+        }
+
+        public IntPtr Handle
+        {
+            get
+            {
+                return handle;
+            }
         }
 
         public Status GetReceivedStatus()
@@ -102,5 +120,11 @@ namespace Grpc.Core.Internal
         {
             return grpcsharp_batch_context_recv_close_on_server_cancelled(this) != 0;
         }
+            
+        protected override bool ReleaseHandle()
+        {
+            grpcsharp_batch_context_destroy(handle);
+            return true;
+        }
     }
 }

src/csharp/Grpc.Core/Internal/CallSafeHandle.cs

@@ -37,8 +37,6 @@ using Grpc.Core.Utils;
 
 namespace Grpc.Core.Internal
 {
-    internal delegate void CompletionCallbackDelegate(bool success, IntPtr batchContextPtr);
-    
     /// <summary>
     /// grpc_call from <grpc/grpc.h>
     /// </summary>
@@ -57,49 +55,40 @@ namespace Grpc.Core.Internal
 
         [DllImport("grpc_csharp_ext.dll")]
         static extern GRPCCallError grpcsharp_call_start_unary(CallSafeHandle call,
-                                                               [MarshalAs(UnmanagedType.FunctionPtr)] CompletionCallbackDelegate callback,
-                                                               byte[] send_buffer, UIntPtr send_buffer_len, MetadataArraySafeHandle metadataArray);
-
-        [DllImport("grpc_csharp_ext.dll")]
-        static extern void grpcsharp_call_blocking_unary(CallSafeHandle call, CompletionQueueSafeHandle dedicatedCq,
-                                                         [MarshalAs(UnmanagedType.FunctionPtr)] CompletionCallbackDelegate callback,
-                                                         byte[] send_buffer, UIntPtr send_buffer_len, MetadataArraySafeHandle metadataArray);
+            BatchContextSafeHandle ctx, byte[] send_buffer, UIntPtr send_buffer_len, MetadataArraySafeHandle metadataArray);
 
         [DllImport("grpc_csharp_ext.dll")]
         static extern GRPCCallError grpcsharp_call_start_client_streaming(CallSafeHandle call,
-                                                                          [MarshalAs(UnmanagedType.FunctionPtr)] CompletionCallbackDelegate callback,
-                                                                          MetadataArraySafeHandle metadataArray);
+            BatchContextSafeHandle ctx, MetadataArraySafeHandle metadataArray);
 
         [DllImport("grpc_csharp_ext.dll")]
         static extern GRPCCallError grpcsharp_call_start_server_streaming(CallSafeHandle call,
-                                                                          [MarshalAs(UnmanagedType.FunctionPtr)] CompletionCallbackDelegate callback,
-                                                                          byte[] send_buffer, UIntPtr send_buffer_len,
-                                                                          MetadataArraySafeHandle metadataArray);
+            BatchContextSafeHandle ctx, byte[] send_buffer, UIntPtr send_buffer_len,
+            MetadataArraySafeHandle metadataArray);
 
         [DllImport("grpc_csharp_ext.dll")]
         static extern GRPCCallError grpcsharp_call_start_duplex_streaming(CallSafeHandle call,
-                                                                          [MarshalAs(UnmanagedType.FunctionPtr)] CompletionCallbackDelegate callback,
-                                                                          MetadataArraySafeHandle metadataArray);
+            BatchContextSafeHandle ctx, MetadataArraySafeHandle metadataArray);
 
         [DllImport("grpc_csharp_ext.dll")]
         static extern GRPCCallError grpcsharp_call_send_message(CallSafeHandle call,
-                                                                [MarshalAs(UnmanagedType.FunctionPtr)] CompletionCallbackDelegate callback,
-                                                                byte[] send_buffer, UIntPtr send_buffer_len);
+            BatchContextSafeHandle ctx, byte[] send_buffer, UIntPtr send_buffer_len);
 
         [DllImport("grpc_csharp_ext.dll")]
         static extern GRPCCallError grpcsharp_call_send_close_from_client(CallSafeHandle call,
-                                                                          [MarshalAs(UnmanagedType.FunctionPtr)] CompletionCallbackDelegate callback);
+            BatchContextSafeHandle ctx);
 
         [DllImport("grpc_csharp_ext.dll")]
-        static extern GRPCCallError grpcsharp_call_send_status_from_server(CallSafeHandle call, [MarshalAs(UnmanagedType.FunctionPtr)] CompletionCallbackDelegate callback, StatusCode statusCode, string statusMessage);
+        static extern GRPCCallError grpcsharp_call_send_status_from_server(CallSafeHandle call, 
+            BatchContextSafeHandle ctx, StatusCode statusCode, string statusMessage);
 
         [DllImport("grpc_csharp_ext.dll")]
         static extern GRPCCallError grpcsharp_call_recv_message(CallSafeHandle call,
-                                                                [MarshalAs(UnmanagedType.FunctionPtr)] CompletionCallbackDelegate callback);
+            BatchContextSafeHandle ctx);
 
         [DllImport("grpc_csharp_ext.dll")]
         static extern GRPCCallError grpcsharp_call_start_serverside(CallSafeHandle call,
-                                                                    [MarshalAs(UnmanagedType.FunctionPtr)] CompletionCallbackDelegate callback);
+            BatchContextSafeHandle ctx);
 
         [DllImport("grpc_csharp_ext.dll")]
         static extern void grpcsharp_call_destroy(IntPtr call);
@@ -113,64 +102,84 @@ namespace Grpc.Core.Internal
             return grpcsharp_channel_create_call(channel, cq, method, host, deadline);
         }
 
-        public void StartUnary(byte[] payload, CompletionCallbackDelegate callback, MetadataArraySafeHandle metadataArray)
+        public void StartUnary(byte[] payload, BatchCompletionDelegate callback, MetadataArraySafeHandle metadataArray)
         {
-            AssertCallOk(grpcsharp_call_start_unary(this, callback, payload, new UIntPtr((ulong)payload.Length), metadataArray));
+            var ctx = BatchContextSafeHandle.Create();
+            GrpcEnvironment.CompletionRegistry.RegisterBatchCompletion(ctx, callback);
+            grpcsharp_call_start_unary(this, ctx, payload, new UIntPtr((ulong)payload.Length), metadataArray)
+                .CheckOk();
         }
 
-        public void BlockingUnary(CompletionQueueSafeHandle dedicatedCq, byte[] payload, CompletionCallbackDelegate callback, MetadataArraySafeHandle metadataArray)
+        public void StartUnary(byte[] payload, BatchContextSafeHandle ctx, MetadataArraySafeHandle metadataArray)
         {
-            grpcsharp_call_blocking_unary(this, dedicatedCq, callback, payload, new UIntPtr((ulong)payload.Length), metadataArray);
+            grpcsharp_call_start_unary(this, ctx, payload, new UIntPtr((ulong)payload.Length), metadataArray)
+                .CheckOk();
         }
 
-        public void StartClientStreaming(CompletionCallbackDelegate callback, MetadataArraySafeHandle metadataArray)
+        public void StartClientStreaming(BatchCompletionDelegate callback, MetadataArraySafeHandle metadataArray)
         {
-            AssertCallOk(grpcsharp_call_start_client_streaming(this, callback, metadataArray));
+            var ctx = BatchContextSafeHandle.Create();
+            GrpcEnvironment.CompletionRegistry.RegisterBatchCompletion(ctx, callback);
+            grpcsharp_call_start_client_streaming(this, ctx, metadataArray).CheckOk();
         }
 
-        public void StartServerStreaming(byte[] payload, CompletionCallbackDelegate callback, MetadataArraySafeHandle metadataArray)
+        public void StartServerStreaming(byte[] payload, BatchCompletionDelegate callback, MetadataArraySafeHandle metadataArray)
         {
-            AssertCallOk(grpcsharp_call_start_server_streaming(this, callback, payload, new UIntPtr((ulong)payload.Length), metadataArray));
+            var ctx = BatchContextSafeHandle.Create();
+            GrpcEnvironment.CompletionRegistry.RegisterBatchCompletion(ctx, callback);
+            grpcsharp_call_start_server_streaming(this, ctx, payload, new UIntPtr((ulong)payload.Length), metadataArray).CheckOk();
         }
 
-        public void StartDuplexStreaming(CompletionCallbackDelegate callback, MetadataArraySafeHandle metadataArray)
+        public void StartDuplexStreaming(BatchCompletionDelegate callback, MetadataArraySafeHandle metadataArray)
         {
-            AssertCallOk(grpcsharp_call_start_duplex_streaming(this, callback, metadataArray));
+            var ctx = BatchContextSafeHandle.Create();
+            GrpcEnvironment.CompletionRegistry.RegisterBatchCompletion(ctx, callback);
+            grpcsharp_call_start_duplex_streaming(this, ctx, metadataArray).CheckOk();
         }
 
-        public void StartSendMessage(byte[] payload, CompletionCallbackDelegate callback)
+        public void StartSendMessage(byte[] payload, BatchCompletionDelegate callback)
         {
-            AssertCallOk(grpcsharp_call_send_message(this, callback, payload, new UIntPtr((ulong)payload.Length)));
+            var ctx = BatchContextSafeHandle.Create();
+            GrpcEnvironment.CompletionRegistry.RegisterBatchCompletion(ctx, callback);
+            grpcsharp_call_send_message(this, ctx, payload, new UIntPtr((ulong)payload.Length)).CheckOk();
         }
 
-        public void StartSendCloseFromClient(CompletionCallbackDelegate callback)
+        public void StartSendCloseFromClient(BatchCompletionDelegate callback)
         {
-            AssertCallOk(grpcsharp_call_send_close_from_client(this, callback));
+            var ctx = BatchContextSafeHandle.Create();
+            GrpcEnvironment.CompletionRegistry.RegisterBatchCompletion(ctx, callback);
+            grpcsharp_call_send_close_from_client(this, ctx).CheckOk();
         }
 
-        public void StartSendStatusFromServer(Status status, CompletionCallbackDelegate callback)
+        public void StartSendStatusFromServer(Status status, BatchCompletionDelegate callback)
         {
-            AssertCallOk(grpcsharp_call_send_status_from_server(this, callback, status.StatusCode, status.Detail));
+            var ctx = BatchContextSafeHandle.Create();
+            GrpcEnvironment.CompletionRegistry.RegisterBatchCompletion(ctx, callback);
+            grpcsharp_call_send_status_from_server(this, ctx, status.StatusCode, status.Detail).CheckOk();
         }
 
-        public void StartReceiveMessage(CompletionCallbackDelegate callback)
+        public void StartReceiveMessage(BatchCompletionDelegate callback)
         {
-            AssertCallOk(grpcsharp_call_recv_message(this, callback));
+            var ctx = BatchContextSafeHandle.Create();
+            GrpcEnvironment.CompletionRegistry.RegisterBatchCompletion(ctx, callback);
+            grpcsharp_call_recv_message(this, ctx).CheckOk();
         }
 
-        public void StartServerSide(CompletionCallbackDelegate callback)
+        public void StartServerSide(BatchCompletionDelegate callback)
         {
-            AssertCallOk(grpcsharp_call_start_serverside(this, callback));
+            var ctx = BatchContextSafeHandle.Create();
+            GrpcEnvironment.CompletionRegistry.RegisterBatchCompletion(ctx, callback);
+            grpcsharp_call_start_serverside(this, ctx).CheckOk();
         }
 
         public void Cancel()
         {
-            AssertCallOk(grpcsharp_call_cancel(this));
+            grpcsharp_call_cancel(this).CheckOk();
         }
 
         public void CancelWithStatus(Status status)
         {
-            AssertCallOk(grpcsharp_call_cancel_with_status(this, status.StatusCode, status.Detail));
+            grpcsharp_call_cancel_with_status(this, status.StatusCode, status.Detail).CheckOk();
         }
 
         protected override bool ReleaseHandle()
@@ -179,11 +188,6 @@ namespace Grpc.Core.Internal
             return true;
         }
 
-        private static void AssertCallOk(GRPCCallError callError)
-        {
-            Preconditions.CheckState(callError == GRPCCallError.GRPC_CALL_OK, "Status not GRPC_CALL_OK");
-        }
-
         private static uint GetFlags(bool buffered)
         {
             return buffered ? 0 : GRPC_WRITE_BUFFER_HINT;

src/csharp/Grpc.Core/Internal/ChannelArgsSafeHandle.cs

@@ -45,6 +45,9 @@ namespace Grpc.Core.Internal
         [DllImport("grpc_csharp_ext.dll", CharSet = CharSet.Ansi)]
         static extern void grpcsharp_channel_args_set_string(ChannelArgsSafeHandle args, UIntPtr index, string key, string value);
 
+        [DllImport("grpc_csharp_ext.dll", CharSet = CharSet.Ansi)]
+        static extern void grpcsharp_channel_args_set_integer(ChannelArgsSafeHandle args, UIntPtr index, string key, int value);
+
         [DllImport("grpc_csharp_ext.dll")]
         static extern void grpcsharp_channel_args_destroy(IntPtr args);
 
@@ -67,6 +70,11 @@ namespace Grpc.Core.Internal
             grpcsharp_channel_args_set_string(this, new UIntPtr((uint)index), key, value);
         }
 
+        public void SetInteger(int index, string key, int value)
+        {
+            grpcsharp_channel_args_set_integer(this, new UIntPtr((uint)index), key, value);
+        }
+
         protected override bool ReleaseHandle()
         {
             grpcsharp_channel_args_destroy(handle);

src/csharp/Grpc.Core/Internal/CompletionQueueEvent.cs

@@ -0,0 +1,60 @@
+#region Copyright notice and license
+
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#endregion
+
+using System;
+using System.Runtime.InteropServices;
+
+namespace Grpc.Core.Internal
+{
+    /// <summary>
+    /// grpc_event from grpc/grpc.h
+    /// </summary>
+    [StructLayout(LayoutKind.Sequential)]
+    internal struct CompletionQueueEvent
+    {
+        [DllImport("grpc_csharp_ext.dll")]
+        static extern int grpcsharp_sizeof_grpc_event();
+
+        public GRPCCompletionType type;
+        public int success;
+        public IntPtr tag;
+
+        internal static int NativeSize
+        {
+            get
+            {
+                return grpcsharp_sizeof_grpc_event();
+            }
+        }
+    }
+}

src/csharp/Grpc.Core/Internal/CompletionQueueSafeHandle.cs

@@ -46,7 +46,10 @@ namespace Grpc.Core.Internal
         static extern void grpcsharp_completion_queue_shutdown(CompletionQueueSafeHandle cq);
 
         [DllImport("grpc_csharp_ext.dll")]
-        static extern GRPCCompletionType grpcsharp_completion_queue_next_with_callback(CompletionQueueSafeHandle cq);
+        static extern CompletionQueueEvent grpcsharp_completion_queue_next(CompletionQueueSafeHandle cq);
+
+        [DllImport("grpc_csharp_ext.dll")]
+        static extern CompletionQueueEvent grpcsharp_completion_queue_pluck(CompletionQueueSafeHandle cq, IntPtr tag);
 
         [DllImport("grpc_csharp_ext.dll")]
         static extern void grpcsharp_completion_queue_destroy(IntPtr cq);
@@ -60,9 +63,14 @@ namespace Grpc.Core.Internal
             return grpcsharp_completion_queue_create();
         }
 
-        public GRPCCompletionType NextWithCallback()
+        public CompletionQueueEvent Next()
+        {
+            return grpcsharp_completion_queue_next(this);
+        }
+
+        public CompletionQueueEvent Pluck(IntPtr tag)
         {
-            return grpcsharp_completion_queue_next_with_callback(this);
+            return grpcsharp_completion_queue_pluck(this, tag);
         }
 
         public void Shutdown()

src/csharp/Grpc.Core/Internal/CompletionRegistry.cs

@@ -0,0 +1,89 @@
+#region Copyright notice and license
+
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#endregion
+
+using System;
+using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.Runtime.InteropServices;
+using Grpc.Core.Utils;
+
+namespace Grpc.Core.Internal
+{
+    internal delegate void OpCompletionDelegate(bool success);
+
+    internal delegate void BatchCompletionDelegate(bool success, BatchContextSafeHandle ctx);
+
+    internal class CompletionRegistry
+    {
+        readonly ConcurrentDictionary<IntPtr, OpCompletionDelegate> dict = new ConcurrentDictionary<IntPtr, OpCompletionDelegate>();  
+
+        public void Register(IntPtr key, OpCompletionDelegate callback)
+        {
+            DebugStats.PendingBatchCompletions.Increment();
+            Preconditions.CheckState(dict.TryAdd(key, callback));
+        }
+
+        public void RegisterBatchCompletion(BatchContextSafeHandle ctx, BatchCompletionDelegate callback)
+        {
+            OpCompletionDelegate opCallback = ((success) => HandleBatchCompletion(success, ctx, callback));
+            Register(ctx.Handle, opCallback);
+        }
+
+        public OpCompletionDelegate Extract(IntPtr key)
+        {
+            OpCompletionDelegate value;
+            Preconditions.CheckState(dict.TryRemove(key, out value));
+            DebugStats.PendingBatchCompletions.Decrement();
+            return value;
+        }
+
+        private static void HandleBatchCompletion(bool success, BatchContextSafeHandle ctx, BatchCompletionDelegate callback)
+        {
+            try
+            {
+                callback(success, ctx);
+            }
+            catch (Exception e)
+            {
+                Console.WriteLine("Exception occured while invoking completion delegate: " + e);
+            }
+            finally
+            {
+                if (ctx != null)
+                {
+                    ctx.Dispose();
+                }
+            }
+        }
+    }
+}

src/csharp/Grpc.Core/Internal/DebugStats.cs

@@ -41,5 +41,7 @@ namespace Grpc.Core.Internal
         public static readonly AtomicCounter ActiveClientCalls = new AtomicCounter();
 
         public static readonly AtomicCounter ActiveServerCalls = new AtomicCounter();
+
+        public static readonly AtomicCounter PendingBatchCompletions = new AtomicCounter();
     }
 }

src/csharp/Grpc.Core/Internal/Enums.cs

@@ -33,35 +33,47 @@
 
 using System;
 using System.Runtime.InteropServices;
+using Grpc.Core.Utils;
 
 namespace Grpc.Core.Internal
 {
     /// <summary>
-    /// from grpc/grpc.h
+    /// grpc_call_error from grpc/grpc.h
     /// </summary>
     internal enum GRPCCallError
     {
         /* everything went ok */
-        GRPC_CALL_OK = 0,
+        OK = 0,
         /* something failed, we don't know what */
-        GRPC_CALL_ERROR,
+        Error,
         /* this method is not available on the server */
-        GRPC_CALL_ERROR_NOT_ON_SERVER,
+        NotOnServer,
         /* this method is not available on the client */
-        GRPC_CALL_ERROR_NOT_ON_CLIENT,
+        NotOnClient,
         /* this method must be called before server_accept */
-        GRPC_CALL_ERROR_ALREADY_ACCEPTED,
+        AlreadyAccepted,
         /* this method must be called before invoke */
-        GRPC_CALL_ERROR_ALREADY_INVOKED,
+        AlreadyInvoked,
         /* this method must be called after invoke */
-        GRPC_CALL_ERROR_NOT_INVOKED,
+        NotInvoked,
         /* this call is already finished
      (writes_done or write_status has already been called) */
-        GRPC_CALL_ERROR_ALREADY_FINISHED,
+        AlreadyFinished,
         /* there is already an outstanding read/write operation on the call */
-        GRPC_CALL_ERROR_TOO_MANY_OPERATIONS,
+        TooManyOperations,
         /* the flags value was illegal for this call */
-        GRPC_CALL_ERROR_INVALID_FLAGS
+        InvalidFlags
+    }
+
+    internal static class CallErrorExtensions
+    {
+        /// <summary>
+        /// Checks the call API invocation's result is OK.
+        /// </summary>
+        public static void CheckOk(this GRPCCallError callError)
+        {
+            Preconditions.CheckState(callError == GRPCCallError.OK, "Call error: " + callError);
+        }
     }
 
     /// <summary>
@@ -70,12 +82,12 @@ namespace Grpc.Core.Internal
     internal enum GRPCCompletionType
     {
         /* Shutting down */
-        GRPC_QUEUE_SHUTDOWN, 
+        Shutdown, 
 
         /* No event before timeout */
-        GRPC_QUEUE_TIMEOUT,  
+        Timeout,  
 
         /* operation completion */
-        GRPC_OP_COMPLETE
+        OpComplete
     }
 }

src/csharp/Grpc.Core/Internal/GrpcThreadPool.cs

@@ -112,12 +112,26 @@ namespace Grpc.Core.Internal
         /// </summary>
         private void RunHandlerLoop()
         {
-            GRPCCompletionType completionType;
+            CompletionQueueEvent ev;
             do
             {
-                completionType = cq.NextWithCallback();
+                ev = cq.Next();
+                if (ev.type == GRPCCompletionType.OpComplete)
+                {
+                    bool success = (ev.success != 0);
+                    IntPtr tag = ev.tag;
+                    try
+                    {
+                        var callback = GrpcEnvironment.CompletionRegistry.Extract(tag);
+                        callback(success);
+                    }
+                    catch (Exception e)
+                    {
+                        Console.WriteLine("Exception occured while invoking completion delegate: " + e);
+                    }
+                }
             }
-            while (completionType != GRPCCompletionType.GRPC_QUEUE_SHUTDOWN);
+            while (ev.type != GRPCCompletionType.Shutdown);
             Console.WriteLine("Completion queue has shutdown successfully, thread " + Thread.CurrentThread.Name + " exiting.");
         }
     }

src/csharp/Grpc.Core/Internal/ServerCallHandler.cs

@@ -267,8 +267,6 @@ namespace Grpc.Core.Internal
             var responseStream = new ServerResponseStream<byte[], byte[]>(asyncCall);
 
             await responseStream.WriteStatusAsync(new Status(StatusCode.Unimplemented, "No such method."));
-            // TODO(jtattermusch): if we don't read what client has sent, the server call never gets disposed.
-            await requestStream.ToList();
             await finishedTask;
         }
     }

src/csharp/Grpc.Core/Internal/ServerSafeHandle.cs

@@ -45,10 +45,7 @@ namespace Grpc.Core.Internal
     internal sealed class ServerSafeHandle : SafeHandleZeroIsInvalid
     {
         [DllImport("grpc_csharp_ext.dll")]
-        static extern GRPCCallError grpcsharp_server_request_call(ServerSafeHandle server, CompletionQueueSafeHandle cq, [MarshalAs(UnmanagedType.FunctionPtr)] CompletionCallbackDelegate callback);
-
-        [DllImport("grpc_csharp_ext.dll")]
-        static extern ServerSafeHandle grpcsharp_server_create(CompletionQueueSafeHandle cq, IntPtr args);
+        static extern ServerSafeHandle grpcsharp_server_create(CompletionQueueSafeHandle cq, ChannelArgsSafeHandle args);
 
         [DllImport("grpc_csharp_ext.dll")]
         static extern int grpcsharp_server_add_http2_port(ServerSafeHandle server, string addr);
@@ -60,11 +57,14 @@ namespace Grpc.Core.Internal
         static extern void grpcsharp_server_start(ServerSafeHandle server);
 
         [DllImport("grpc_csharp_ext.dll")]
-        static extern void grpcsharp_server_shutdown_and_notify_callback(ServerSafeHandle server, CompletionQueueSafeHandle cq, [MarshalAs(UnmanagedType.FunctionPtr)] CompletionCallbackDelegate callback);
+        static extern GRPCCallError grpcsharp_server_request_call(ServerSafeHandle server, CompletionQueueSafeHandle cq, BatchContextSafeHandle ctx);
 
         [DllImport("grpc_csharp_ext.dll")]
         static extern void grpcsharp_server_cancel_all_calls(ServerSafeHandle server);
 
+        [DllImport("grpc_csharp_ext.dll")]
+        static extern void grpcsharp_server_shutdown_and_notify_callback(ServerSafeHandle server, CompletionQueueSafeHandle cq, BatchContextSafeHandle ctx);
+
         [DllImport("grpc_csharp_ext.dll")]
         static extern void grpcsharp_server_destroy(IntPtr server);
 
@@ -72,7 +72,7 @@ namespace Grpc.Core.Internal
         {
         }
 
-        public static ServerSafeHandle NewServer(CompletionQueueSafeHandle cq, IntPtr args)
+        public static ServerSafeHandle NewServer(CompletionQueueSafeHandle cq, ChannelArgsSafeHandle args)
         {
             return grpcsharp_server_create(cq, args);
         }
@@ -91,15 +91,19 @@ namespace Grpc.Core.Internal
         {
             grpcsharp_server_start(this);
         }
-
-        public void ShutdownAndNotify(CompletionQueueSafeHandle cq, CompletionCallbackDelegate callback)
+            
+        public void ShutdownAndNotify(CompletionQueueSafeHandle cq, BatchCompletionDelegate callback)
         {
-            grpcsharp_server_shutdown_and_notify_callback(this, cq, callback);
+            var ctx = BatchContextSafeHandle.Create();
+            GrpcEnvironment.CompletionRegistry.RegisterBatchCompletion(ctx, callback);
+            grpcsharp_server_shutdown_and_notify_callback(this, cq, ctx);
         }
 
-        public void RequestCall(CompletionQueueSafeHandle cq, CompletionCallbackDelegate callback)
+        public void RequestCall(CompletionQueueSafeHandle cq, BatchCompletionDelegate callback)
         {
-            AssertCallOk(grpcsharp_server_request_call(this, cq, callback));
+            var ctx = BatchContextSafeHandle.Create();
+            GrpcEnvironment.CompletionRegistry.RegisterBatchCompletion(ctx, callback);
+            grpcsharp_server_request_call(this, cq, ctx).CheckOk();
         }
 
         protected override bool ReleaseHandle()
@@ -113,10 +117,5 @@ namespace Grpc.Core.Internal
         {
             grpcsharp_server_cancel_all_calls(this);
         }
-
-        private static void AssertCallOk(GRPCCallError callError)
-        {
-            Preconditions.CheckState(callError == GRPCCallError.GRPC_CALL_OK, "Status not GRPC_CALL_OK");
-        }
     }
 }

src/csharp/Grpc.Core/Internal/Timespec.cs

@@ -51,7 +51,7 @@ namespace Grpc.Core.Internal
 
         [DllImport("grpc_csharp_ext.dll")]
         static extern int gprsharp_sizeof_timespec();
-        // TODO: revisit this.
+
         // NOTE: on linux 64bit  sizeof(gpr_timespec) = 16, on windows 32bit sizeof(gpr_timespec) = 8
         // so IntPtr seems to have the right size to work on both.
         public System.IntPtr tv_sec;

src/csharp/Grpc.Core/Server.cs

@@ -52,11 +52,6 @@ namespace Grpc.Core
         /// </summary>
         public const int PickUnusedPort = 0;
 
-        // TODO(jtattermusch) : make sure the delegate doesn't get garbage collected while
-        // native callbacks are in the completion queue.
-        readonly CompletionCallbackDelegate serverShutdownHandler;
-        readonly CompletionCallbackDelegate newServerRpcHandler;
-
         readonly ServerSafeHandle handle;
         readonly object myLock = new object();
 
@@ -66,11 +61,16 @@ namespace Grpc.Core
         bool startRequested;
         bool shutdownRequested;
 
-        public Server()
+        /// <summary>
+        /// Create a new server.
+        /// </summary>
+        /// <param name="options">Channel options.</param>
+        public Server(IEnumerable<ChannelOption> options = null)
         {
-            this.handle = ServerSafeHandle.NewServer(GetCompletionQueue(), IntPtr.Zero);
-            this.newServerRpcHandler = HandleNewServerRpc;
-            this.serverShutdownHandler = HandleServerShutdown;
+            using (var channelArgs = ChannelOptions.CreateChannelArgs(options))
+            {
+                this.handle = ServerSafeHandle.NewServer(GetCompletionQueue(), channelArgs);
+            }
         }
 
         /// <summary>
@@ -108,7 +108,7 @@ namespace Grpc.Core
         /// </summary>
         /// <returns>The port on which server will be listening.</returns>
         /// <param name="host">the host</param>
-        /// <param name="port">the port. If zero, , an unused port is chosen automatically.</param>
+        /// <param name="port">the port. If zero, an unused port is chosen automatically.</param>
         public int AddListeningPort(string host, int port, ServerCredentials credentials)
         {
             Preconditions.CheckNotNull(credentials);
@@ -144,7 +144,7 @@ namespace Grpc.Core
                 shutdownRequested = true;
             }
 
-            handle.ShutdownAndNotify(GetCompletionQueue(), serverShutdownHandler);
+            handle.ShutdownAndNotify(GetCompletionQueue(), HandleServerShutdown);
             await shutdownTcs.Task;
             handle.Dispose();
         }
@@ -173,7 +173,7 @@ namespace Grpc.Core
                 shutdownRequested = true;
             }
 
-            handle.ShutdownAndNotify(GetCompletionQueue(), serverShutdownHandler);
+            handle.ShutdownAndNotify(GetCompletionQueue(), HandleServerShutdown);
             handle.CancelAllCalls();
             await shutdownTcs.Task;
             handle.Dispose();
@@ -208,7 +208,7 @@ namespace Grpc.Core
             {
                 if (!shutdownRequested)
                 {
-                    handle.RequestCall(GetCompletionQueue(), newServerRpcHandler);
+                    handle.RequestCall(GetCompletionQueue(), HandleNewServerRpc);
                 }
             }
         }
@@ -236,44 +236,28 @@ namespace Grpc.Core
         /// <summary>
         /// Handles the native callback.
         /// </summary>
-        private void HandleNewServerRpc(bool success, IntPtr batchContextPtr)
+        private void HandleNewServerRpc(bool success, BatchContextSafeHandle ctx)
         {
-            try
-            {
-                var ctx = new BatchContextSafeHandleNotOwned(batchContextPtr);
-
-                // TODO: handle error
+            // TODO: handle error
 
-                CallSafeHandle call = ctx.GetServerRpcNewCall();
-                string method = ctx.GetServerRpcNewMethod();
-
-                // after server shutdown, the callback returns with null call
-                if (!call.IsInvalid)
-                {
-                    Task.Run(async () => await InvokeCallHandler(call, method));
-                }
+            CallSafeHandle call = ctx.GetServerRpcNewCall();
+            string method = ctx.GetServerRpcNewMethod();
 
-                AllowOneRpc();
-            }
-            catch (Exception e)
+            // after server shutdown, the callback returns with null call
+            if (!call.IsInvalid)
             {
-                Console.WriteLine("Caught exception in a native handler: " + e);
+                Task.Run(async () => await InvokeCallHandler(call, method));
             }
+
+            AllowOneRpc();
         }
 
         /// <summary>
         /// Handles native callback.
         /// </summary>
-        private void HandleServerShutdown(bool success, IntPtr batchContextPtr)
+        private void HandleServerShutdown(bool success, BatchContextSafeHandle ctx)
         {
-            try
-            {
-                shutdownTcs.SetResult(null);
-            }
-            catch (Exception e)
-            {
-                Console.WriteLine("Caught exception in a native handler: " + e);
-            }
+            shutdownTcs.SetResult(null);
         }
 
         private static CompletionQueueSafeHandle GetCompletionQueue()

src/csharp/Grpc.Examples.MathClient/MathClient.cs

@@ -41,7 +41,7 @@ namespace math
         {
             GrpcEnvironment.Initialize();
 
-            using (Channel channel = new Channel("127.0.0.1:23456"))
+            using (Channel channel = new Channel("127.0.0.1", 23456))
             {
                 Math.IMathClient stub = new Math.MathClient(channel);
                 MathExamples.DivExample(stub);

src/csharp/Grpc.Examples.Tests/MathClientServerTests.cs

@@ -60,7 +60,7 @@ namespace math.Tests
             server.AddServiceDefinition(Math.BindService(new MathServiceImpl()));
             int port = server.AddListeningPort(host, Server.PickUnusedPort);
             server.Start();
-            channel = new Channel(host + ":" + port);
+            channel = new Channel(host, port);
 
             // TODO(jtattermusch): get rid of the custom header here once we have dedicated tests
             // for header support.

src/csharp/Grpc.IntegrationTesting/InteropClient.cs

@@ -104,22 +104,22 @@ namespace Grpc.IntegrationTesting
         {
             GrpcEnvironment.Initialize();
 
-            string addr = string.Format("{0}:{1}", options.serverHost, options.serverPort);
-
             Credentials credentials = null;
             if (options.useTls)
             {
                 credentials = TestCredentials.CreateTestClientCredentials(options.useTestCa);
             }
 
-            ChannelArgs channelArgs = null;
+            List<ChannelOption> channelOptions = null;
             if (!string.IsNullOrEmpty(options.serverHostOverride))
             {
-                channelArgs = ChannelArgs.CreateBuilder()
-                    .AddString(ChannelArgs.SslTargetNameOverrideKey, options.serverHostOverride).Build();
+                channelOptions = new List<ChannelOption>
+                {
+                    new ChannelOption(ChannelOptions.SslTargetNameOverride, options.serverHostOverride)
+                };
             }
 
-            using (Channel channel = new Channel(addr, credentials, channelArgs))
+            using (Channel channel = new Channel(options.serverHost, options.serverPort.Value, credentials, channelOptions))
             {
                 var stubConfig = StubConfiguration.Default;
                 if (options.testCase == "service_account_creds" || options.testCase == "compute_engine_creds")

src/csharp/Grpc.IntegrationTesting/InteropClientServerTest.cs

@@ -62,10 +62,11 @@ namespace Grpc.IntegrationTesting
             int port = server.AddListeningPort(host, Server.PickUnusedPort, TestCredentials.CreateTestServerCredentials());
             server.Start();
 
-            var channelArgs = ChannelArgs.CreateBuilder()
-                .AddString(ChannelArgs.SslTargetNameOverrideKey, TestCredentials.DefaultHostOverride).Build();
-
-            channel = new Channel(host + ":" + port, TestCredentials.CreateTestClientCredentials(true), channelArgs);
+            var options = new List<ChannelOption>
+            {
+                new ChannelOption(ChannelOptions.SslTargetNameOverride, TestCredentials.DefaultHostOverride)
+            };
+            channel = new Channel(host, port, TestCredentials.CreateTestClientCredentials(true), options);
             client = TestService.NewStub(channel);
         }
 

src/csharp/ext/grpc_csharp_ext.c

@@ -60,13 +60,11 @@
 
 grpc_byte_buffer *string_to_byte_buffer(const char *buffer, size_t len) {
   gpr_slice slice = gpr_slice_from_copied_buffer(buffer, len);
-  grpc_byte_buffer *bb = grpc_byte_buffer_create(&slice, 1);
+  grpc_byte_buffer *bb = grpc_raw_byte_buffer_create(&slice, 1);
   gpr_slice_unref(slice);
   return bb;
 }
 
-typedef void(GPR_CALLTYPE *callback_funcptr)(gpr_int32 success, void *batch_context);
-
 /*
  * Helper to maintain lifetime of batch op inputs and store batch op outputs.
  */
@@ -91,13 +89,9 @@ typedef struct gprcsharp_batch_context {
     grpc_call_details call_details;
     grpc_metadata_array request_metadata;
   } server_rpc_new;
-
-  /* callback will be called upon completion */
-  callback_funcptr callback;
-
 } grpcsharp_batch_context;
 
-grpcsharp_batch_context *grpcsharp_batch_context_create() {
+GPR_EXPORT grpcsharp_batch_context *GPR_CALLTYPE grpcsharp_batch_context_create() {
   grpcsharp_batch_context *ctx = gpr_malloc(sizeof(grpcsharp_batch_context));
   memset(ctx, 0, sizeof(grpcsharp_batch_context));
   return ctx;
@@ -192,7 +186,7 @@ void grpcsharp_metadata_array_move(grpc_metadata_array *dest,
   src->metadata = NULL;
 }
 
-void grpcsharp_batch_context_destroy(grpcsharp_batch_context *ctx) {
+GPR_EXPORT void GPR_CALLTYPE grpcsharp_batch_context_destroy(grpcsharp_batch_context *ctx) {
   if (!ctx) {
     return;
   }
@@ -306,25 +300,14 @@ grpcsharp_completion_queue_destroy(grpc_completion_queue *cq) {
   grpc_completion_queue_destroy(cq);
 }
 
-GPR_EXPORT grpc_completion_type GPR_CALLTYPE
-grpcsharp_completion_queue_next_with_callback(grpc_completion_queue *cq) {
-  grpc_event ev;
-  grpcsharp_batch_context *batch_context;
-  grpc_completion_type t;
-
-  ev = grpc_completion_queue_next(cq, gpr_inf_future);
-  t = ev.type;
-  if (t == GRPC_OP_COMPLETE && ev.tag) {
-    /* NEW API handler */
-    batch_context = (grpcsharp_batch_context *)ev.tag;
-    batch_context->callback((gpr_int32) ev.success, batch_context);
-    grpcsharp_batch_context_destroy(batch_context);
-  }
+GPR_EXPORT grpc_event GPR_CALLTYPE
+grpcsharp_completion_queue_next(grpc_completion_queue *cq) {
+  return grpc_completion_queue_next(cq, gpr_inf_future);
+}
 
-  /* return completion type to allow some handling for events that have no
-   * tag - such as GRPC_QUEUE_SHUTDOWN
-   */
-  return t;
+GPR_EXPORT grpc_event GPR_CALLTYPE
+grpcsharp_completion_queue_pluck(grpc_completion_queue *cq, void *tag) {
+  return grpc_completion_queue_pluck(cq, tag, gpr_inf_future);
 }
 
 /* Channel */
@@ -369,6 +352,16 @@ grpcsharp_channel_args_set_string(grpc_channel_args *args, size_t index,
   args->args[index].value.string = gpr_strdup(value);
 }
 
+GPR_EXPORT void GPR_CALLTYPE
+grpcsharp_channel_args_set_integer(grpc_channel_args *args, size_t index,
+                                  const char *key, int value) {
+  GPR_ASSERT(args);
+  GPR_ASSERT(index < args->num_args);
+  args->args[index].type = GRPC_ARG_INTEGER;
+  args->args[index].key = gpr_strdup(key);
+  args->args[index].value.integer = value;
+}
+
 GPR_EXPORT void GPR_CALLTYPE
 grpcsharp_channel_args_destroy(grpc_channel_args *args) {
   size_t i;
@@ -413,32 +406,34 @@ GPR_EXPORT void GPR_CALLTYPE grpcsharp_call_destroy(grpc_call *call) {
 }
 
 GPR_EXPORT grpc_call_error GPR_CALLTYPE
-grpcsharp_call_start_unary(grpc_call *call, callback_funcptr callback,
+grpcsharp_call_start_unary(grpc_call *call, grpcsharp_batch_context *ctx,
                            const char *send_buffer, size_t send_buffer_len,
                            grpc_metadata_array *initial_metadata) {
   /* TODO: don't use magic number */
   grpc_op ops[6];
-  grpcsharp_batch_context *ctx = grpcsharp_batch_context_create();
-  ctx->callback = callback;
-
   ops[0].op = GRPC_OP_SEND_INITIAL_METADATA;
   grpcsharp_metadata_array_move(&(ctx->send_initial_metadata),
                                 initial_metadata);
   ops[0].data.send_initial_metadata.count = ctx->send_initial_metadata.count;
   ops[0].data.send_initial_metadata.metadata =
       ctx->send_initial_metadata.metadata;
+  ops[0].flags = 0;
 
   ops[1].op = GRPC_OP_SEND_MESSAGE;
   ctx->send_message = string_to_byte_buffer(send_buffer, send_buffer_len);
   ops[1].data.send_message = ctx->send_message;
+  ops[1].flags = 0;
 
   ops[2].op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
+  ops[2].flags = 0;
 
   ops[3].op = GRPC_OP_RECV_INITIAL_METADATA;
   ops[3].data.recv_initial_metadata = &(ctx->recv_initial_metadata);
+  ops[3].flags = 0;
 
   ops[4].op = GRPC_OP_RECV_MESSAGE;
   ops[4].data.recv_message = &(ctx->recv_message);
+  ops[4].flags = 0;
 
   ops[5].op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   ops[5].data.recv_status_on_client.trailing_metadata =
@@ -450,50 +445,32 @@ grpcsharp_call_start_unary(grpc_call *call, callback_funcptr callback,
       &(ctx->recv_status_on_client.status_details);
   ops[5].data.recv_status_on_client.status_details_capacity =
       &(ctx->recv_status_on_client.status_details_capacity);
+  ops[5].flags = 0;
 
   return grpc_call_start_batch(call, ops, sizeof(ops) / sizeof(ops[0]), ctx);
 }
 
-/* Synchronous unary call */
-GPR_EXPORT void GPR_CALLTYPE
-grpcsharp_call_blocking_unary(grpc_call *call,
-                              grpc_completion_queue *dedicated_cq,
-                              callback_funcptr callback,
-                              const char *send_buffer, size_t send_buffer_len,
-                              grpc_metadata_array *initial_metadata) {
-  GPR_ASSERT(grpcsharp_call_start_unary(call, callback, send_buffer,
-                                        send_buffer_len,
-                                        initial_metadata) == GRPC_CALL_OK);
-
-  /* TODO: we would like to use pluck, but we don't know the tag */
-  GPR_ASSERT(grpcsharp_completion_queue_next_with_callback(dedicated_cq) ==
-             GRPC_OP_COMPLETE);
-  grpc_completion_queue_shutdown(dedicated_cq);
-  GPR_ASSERT(grpcsharp_completion_queue_next_with_callback(dedicated_cq) ==
-             GRPC_QUEUE_SHUTDOWN);
-}
-
 GPR_EXPORT grpc_call_error GPR_CALLTYPE
 grpcsharp_call_start_client_streaming(grpc_call *call,
-                                      callback_funcptr callback,
+                                      grpcsharp_batch_context *ctx,
                                       grpc_metadata_array *initial_metadata) {
   /* TODO: don't use magic number */
   grpc_op ops[4];
-  grpcsharp_batch_context *ctx = grpcsharp_batch_context_create();
-  ctx->callback = callback;
-
   ops[0].op = GRPC_OP_SEND_INITIAL_METADATA;
   grpcsharp_metadata_array_move(&(ctx->send_initial_metadata),
                                 initial_metadata);
   ops[0].data.send_initial_metadata.count = ctx->send_initial_metadata.count;
   ops[0].data.send_initial_metadata.metadata =
       ctx->send_initial_metadata.metadata;
+  ops[0].flags = 0;
 
   ops[1].op = GRPC_OP_RECV_INITIAL_METADATA;
   ops[1].data.recv_initial_metadata = &(ctx->recv_initial_metadata);
+  ops[1].flags = 0;
 
   ops[2].op = GRPC_OP_RECV_MESSAGE;
   ops[2].data.recv_message = &(ctx->recv_message);
+  ops[2].flags = 0;
 
   ops[3].op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   ops[3].data.recv_status_on_client.trailing_metadata =
@@ -505,33 +482,35 @@ grpcsharp_call_start_client_streaming(grpc_call *call,
       &(ctx->recv_status_on_client.status_details);
   ops[3].data.recv_status_on_client.status_details_capacity =
       &(ctx->recv_status_on_client.status_details_capacity);
+  ops[3].flags = 0;
 
   return grpc_call_start_batch(call, ops, sizeof(ops) / sizeof(ops[0]), ctx);
 }
 
 GPR_EXPORT grpc_call_error GPR_CALLTYPE grpcsharp_call_start_server_streaming(
-    grpc_call *call, callback_funcptr callback, const char *send_buffer,
+    grpc_call *call, grpcsharp_batch_context *ctx, const char *send_buffer,
     size_t send_buffer_len, grpc_metadata_array *initial_metadata) {
   /* TODO: don't use magic number */
   grpc_op ops[5];
-  grpcsharp_batch_context *ctx = grpcsharp_batch_context_create();
-  ctx->callback = callback;
-
   ops[0].op = GRPC_OP_SEND_INITIAL_METADATA;
   grpcsharp_metadata_array_move(&(ctx->send_initial_metadata),
                                 initial_metadata);
   ops[0].data.send_initial_metadata.count = ctx->send_initial_metadata.count;
   ops[0].data.send_initial_metadata.metadata =
       ctx->send_initial_metadata.metadata;
+  ops[0].flags = 0;
 
   ops[1].op = GRPC_OP_SEND_MESSAGE;
   ctx->send_message = string_to_byte_buffer(send_buffer, send_buffer_len);
   ops[1].data.send_message = ctx->send_message;
+  ops[1].flags = 0;
 
   ops[2].op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
+  ops[2].flags = 0;
 
   ops[3].op = GRPC_OP_RECV_INITIAL_METADATA;
   ops[3].data.recv_initial_metadata = &(ctx->recv_initial_metadata);
+  ops[3].flags = 0;
 
   ops[4].op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   ops[4].data.recv_status_on_client.trailing_metadata =
@@ -543,28 +522,28 @@ GPR_EXPORT grpc_call_error GPR_CALLTYPE grpcsharp_call_start_server_streaming(
       &(ctx->recv_status_on_client.status_details);
   ops[4].data.recv_status_on_client.status_details_capacity =
       &(ctx->recv_status_on_client.status_details_capacity);
+  ops[4].flags = 0;
 
   return grpc_call_start_batch(call, ops, sizeof(ops) / sizeof(ops[0]), ctx);
 }
 
 GPR_EXPORT grpc_call_error GPR_CALLTYPE
 grpcsharp_call_start_duplex_streaming(grpc_call *call,
-                                      callback_funcptr callback,
+                                      grpcsharp_batch_context *ctx,
                                       grpc_metadata_array *initial_metadata) {
   /* TODO: don't use magic number */
   grpc_op ops[3];
-  grpcsharp_batch_context *ctx = grpcsharp_batch_context_create();
-  ctx->callback = callback;
-
   ops[0].op = GRPC_OP_SEND_INITIAL_METADATA;
   grpcsharp_metadata_array_move(&(ctx->send_initial_metadata),
                                 initial_metadata);
   ops[0].data.send_initial_metadata.count = ctx->send_initial_metadata.count;
   ops[0].data.send_initial_metadata.metadata =
       ctx->send_initial_metadata.metadata;
+  ops[0].flags = 0;
 
   ops[1].op = GRPC_OP_RECV_INITIAL_METADATA;
   ops[1].data.recv_initial_metadata = &(ctx->recv_initial_metadata);
+  ops[1].flags = 0;
 
   ops[2].op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   ops[2].data.recv_status_on_client.trailing_metadata =
@@ -576,85 +555,76 @@ grpcsharp_call_start_duplex_streaming(grpc_call *call,
       &(ctx->recv_status_on_client.status_details);
   ops[2].data.recv_status_on_client.status_details_capacity =
       &(ctx->recv_status_on_client.status_details_capacity);
+  ops[2].flags = 0;
 
   return grpc_call_start_batch(call, ops, sizeof(ops) / sizeof(ops[0]), ctx);
 }
 
 GPR_EXPORT grpc_call_error GPR_CALLTYPE
-grpcsharp_call_send_message(grpc_call *call, callback_funcptr callback,
+grpcsharp_call_send_message(grpc_call *call, grpcsharp_batch_context *ctx,
                             const char *send_buffer, size_t send_buffer_len) {
   /* TODO: don't use magic number */
   grpc_op ops[1];
-  grpcsharp_batch_context *ctx = grpcsharp_batch_context_create();
-  ctx->callback = callback;
-
   ops[0].op = GRPC_OP_SEND_MESSAGE;
   ctx->send_message = string_to_byte_buffer(send_buffer, send_buffer_len);
   ops[0].data.send_message = ctx->send_message;
+  ops[0].flags = 0;
 
   return grpc_call_start_batch(call, ops, sizeof(ops) / sizeof(ops[0]), ctx);
 }
 
 GPR_EXPORT grpc_call_error GPR_CALLTYPE
 grpcsharp_call_send_close_from_client(grpc_call *call,
-                                      callback_funcptr callback) {
+                                      grpcsharp_batch_context *ctx) {
   /* TODO: don't use magic number */
   grpc_op ops[1];
-  grpcsharp_batch_context *ctx = grpcsharp_batch_context_create();
-  ctx->callback = callback;
-
   ops[0].op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
+  ops[0].flags = 0;
 
   return grpc_call_start_batch(call, ops, sizeof(ops) / sizeof(ops[0]), ctx);
 }
 
 GPR_EXPORT grpc_call_error GPR_CALLTYPE
 grpcsharp_call_send_status_from_server(grpc_call *call,
-                                       callback_funcptr callback,
+                                       grpcsharp_batch_context *ctx,
                                        grpc_status_code status_code,
                                        const char *status_details) {
   /* TODO: don't use magic number */
   grpc_op ops[1];
-  grpcsharp_batch_context *ctx = grpcsharp_batch_context_create();
-  ctx->callback = callback;
-
   ops[0].op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   ops[0].data.send_status_from_server.status = status_code;
   ops[0].data.send_status_from_server.status_details =
       gpr_strdup(status_details);
   ops[0].data.send_status_from_server.trailing_metadata = NULL;
   ops[0].data.send_status_from_server.trailing_metadata_count = 0;
+  ops[0].flags = 0;
 
   return grpc_call_start_batch(call, ops, sizeof(ops) / sizeof(ops[0]), ctx);
 }
 
 GPR_EXPORT grpc_call_error GPR_CALLTYPE
-grpcsharp_call_recv_message(grpc_call *call, callback_funcptr callback) {
+grpcsharp_call_recv_message(grpc_call *call, grpcsharp_batch_context *ctx) {
   /* TODO: don't use magic number */
   grpc_op ops[1];
-  grpcsharp_batch_context *ctx = grpcsharp_batch_context_create();
-  ctx->callback = callback;
-
   ops[0].op = GRPC_OP_RECV_MESSAGE;
   ops[0].data.recv_message = &(ctx->recv_message);
+  ops[0].flags = 0;
   return grpc_call_start_batch(call, ops, sizeof(ops) / sizeof(ops[0]), ctx);
 }
 
 GPR_EXPORT grpc_call_error GPR_CALLTYPE
-grpcsharp_call_start_serverside(grpc_call *call, callback_funcptr callback) {
+grpcsharp_call_start_serverside(grpc_call *call, grpcsharp_batch_context *ctx) {
   /* TODO: don't use magic number */
   grpc_op ops[2];
-
-  grpcsharp_batch_context *ctx = grpcsharp_batch_context_create();
-  ctx->callback = callback;
-
   ops[0].op = GRPC_OP_SEND_INITIAL_METADATA;
   ops[0].data.send_initial_metadata.count = 0;
   ops[0].data.send_initial_metadata.metadata = NULL;
+  ops[0].flags = 0;
 
   ops[1].op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   ops[1].data.recv_close_on_server.cancelled =
       (&ctx->recv_close_on_server_cancelled);
+  ops[1].flags = 0;
 
   return grpc_call_start_batch(call, ops, sizeof(ops) / sizeof(ops[0]), ctx);
 }
@@ -681,9 +651,7 @@ GPR_EXPORT void GPR_CALLTYPE grpcsharp_server_start(grpc_server *server) {
 GPR_EXPORT void GPR_CALLTYPE
 grpcsharp_server_shutdown_and_notify_callback(grpc_server *server,
                                               grpc_completion_queue *cq,
-                                              callback_funcptr callback) {
-  grpcsharp_batch_context *ctx = grpcsharp_batch_context_create();
-  ctx->callback = callback;
+                                              grpcsharp_batch_context *ctx) {
   grpc_server_shutdown_and_notify(server, cq, ctx);
 }
 
@@ -697,10 +665,7 @@ GPR_EXPORT void GPR_CALLTYPE grpcsharp_server_destroy(grpc_server *server) {
 
 GPR_EXPORT grpc_call_error GPR_CALLTYPE
 grpcsharp_server_request_call(grpc_server *server, grpc_completion_queue *cq,
-                              callback_funcptr callback) {
-  grpcsharp_batch_context *ctx = grpcsharp_batch_context_create();
-  ctx->callback = callback;
-
+                              grpcsharp_batch_context *ctx) {
   return grpc_server_request_call(
       server, &(ctx->server_rpc_new.call), &(ctx->server_rpc_new.call_details),
       &(ctx->server_rpc_new.request_metadata), cq, cq, ctx);
@@ -789,11 +754,18 @@ GPR_EXPORT void GPR_CALLTYPE grpcsharp_redirect_log(grpcsharp_log_func func) {
   gpr_set_log_function(grpcsharp_log_handler);
 }
 
+typedef void(GPR_CALLTYPE *test_callback_funcptr)(gpr_int32 success);
+
 /* For testing */
 GPR_EXPORT void GPR_CALLTYPE
-grpcsharp_test_callback(callback_funcptr callback) {
-  callback(1, NULL);
+grpcsharp_test_callback(test_callback_funcptr callback) {
+  callback(1);
 }
 
 /* For testing */
 GPR_EXPORT void *GPR_CALLTYPE grpcsharp_test_nop(void *ptr) { return ptr; }
+
+/* For testing */
+GPR_EXPORT gpr_int32 GPR_CALLTYPE grpcsharp_sizeof_grpc_event(void) {
+  return sizeof(grpc_event);
+}

src/node/ext/byte_buffer.cc

@@ -57,7 +57,7 @@ grpc_byte_buffer *BufferToByteBuffer(Handle<Value> buffer) {
   char *data = ::node::Buffer::Data(buffer);
   gpr_slice slice = gpr_slice_malloc(length);
   memcpy(GPR_SLICE_START_PTR(slice), data, length);
-  grpc_byte_buffer *byte_buffer(grpc_byte_buffer_create(&slice, 1));
+  grpc_byte_buffer *byte_buffer(grpc_raw_byte_buffer_create(&slice, 1));
   gpr_slice_unref(slice);
   return byte_buffer;
 }

src/node/ext/call.cc

@@ -550,6 +550,7 @@ NAN_METHOD(Call::StartBatch) {
     }
     uint32_t type = keys->Get(i)->Uint32Value();
     ops[i].op = static_cast<grpc_op_type>(type);
+    ops[i].flags = 0;
     switch (type) {
       case GRPC_OP_SEND_INITIAL_METADATA:
         op.reset(new SendMetadataOp());

src/node/package.json

@@ -1,6 +1,6 @@
 {
   "name": "grpc",
-  "version": "0.9.0",
+  "version": "0.9.1",
   "author": "Google Inc.",
   "description": "gRPC Library for Node",
   "homepage": "http://www.grpc.io/",

src/node/src/common.js

@@ -47,7 +47,9 @@ function deserializeCls(cls) {
    * @return {cls} The resulting object
    */
   return function deserialize(arg_buf) {
-    return cls.decode(arg_buf).toRaw();
+    // Convert to a native object with binary fields as Buffers (first argument)
+    // and longs as strings (second argument)
+    return cls.decode(arg_buf).toRaw(false, true);
   };
 }
 

src/node/test/common_test.js

@@ -0,0 +1,90 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+'use strict';
+
+var assert = require('assert');
+
+var common = require('../src/common.js');
+
+var ProtoBuf = require('protobufjs');
+
+var messages_proto = ProtoBuf.loadProtoFile(
+    __dirname + '/test_messages.proto').build();
+
+describe('Proto message serialize and deserialize', function() {
+  var longSerialize = common.serializeCls(messages_proto.LongValues);
+  var longDeserialize = common.deserializeCls(messages_proto.LongValues);
+  var pos_value = '314159265358979';
+  var neg_value = '-27182818284590';
+  it('should preserve positive int64 values', function() {
+    var serialized = longSerialize({int_64: pos_value});
+    assert.strictEqual(longDeserialize(serialized).int_64.toString(),
+                       pos_value);
+  });
+  it('should preserve negative int64 values', function() {
+    var serialized = longSerialize({int_64: neg_value});
+    assert.strictEqual(longDeserialize(serialized).int_64.toString(),
+                       neg_value);
+  });
+  it('should preserve uint64 values', function() {
+    var serialized = longSerialize({uint_64: pos_value});
+    assert.strictEqual(longDeserialize(serialized).uint_64.toString(),
+                       pos_value);
+  });
+  it('should preserve positive sint64 values', function() {
+    var serialized = longSerialize({sint_64: pos_value});
+    assert.strictEqual(longDeserialize(serialized).sint_64.toString(),
+                       pos_value);
+  });
+  it('should preserve negative sint64 values', function() {
+    var serialized = longSerialize({sint_64: neg_value});
+    assert.strictEqual(longDeserialize(serialized).sint_64.toString(),
+                       neg_value);
+  });
+  it('should preserve fixed64 values', function() {
+    var serialized = longSerialize({fixed_64: pos_value});
+    assert.strictEqual(longDeserialize(serialized).fixed_64.toString(),
+                       pos_value);
+  });
+  it('should preserve positive sfixed64 values', function() {
+    var serialized = longSerialize({sfixed_64: pos_value});
+    assert.strictEqual(longDeserialize(serialized).sfixed_64.toString(),
+                       pos_value);
+  });
+  it('should preserve negative sfixed64 values', function() {
+    var serialized = longSerialize({sfixed_64: neg_value});
+    assert.strictEqual(longDeserialize(serialized).sfixed_64.toString(),
+                       neg_value);
+  });
+});

src/node/test/test_messages.proto

@@ -0,0 +1,38 @@
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+syntax = "proto3";
+
+message LongValues {
+  int64 int_64 = 1;
+  uint64 uint_64 = 2;
+  sint64 sint_64 = 3;
+  fixed64 fixed_64 = 4;
+  sfixed64 sfixed_64 = 5;
+}

src/objective-c/GRPCClient/GRPCCall.h

@@ -31,43 +31,55 @@
  *
  */
 
+// The gRPC protocol is an RPC protocol on top of HTTP2.
+//
+// While the most common type of RPC receives only one request message and returns only one response
+// message, the protocol also supports RPCs that return multiple individual messages in a streaming
+// fashion, RPCs that accept a stream of request messages, or RPCs with both streaming requests and
+// responses.
+//
+// Conceptually, each gRPC call consists of a bidirectional stream of binary messages, with RPCs of
+// the "non-streaming type" sending only one message in the corresponding direction (the protocol
+// doesn't make any distinction).
+//
+// Each RPC uses a different HTTP2 stream, and thus multiple simultaneous RPCs can be multiplexed
+// transparently on the same TCP connection.
+
 #import <Foundation/Foundation.h>
 #import <gRPC/GRXWriter.h>
 
 @class GRPCMethodName;
 
-@class GRPCCall;
+// Key used in |NSError|'s |userInfo| dictionary to store the response metadata sent by the server.
+extern id const kGRPCStatusMetadataKey;
 
-// The gRPC protocol is an RPC protocol on top of HTTP2.
-//
-// While the most common type of RPC receives only one request message and
-// returns only one response message, the protocol also supports RPCs that
-// return multiple individual messages in a streaming fashion, RPCs that
-// accept a stream of request messages, or RPCs with both streaming requests
-// and responses.
-//
-// Conceptually, each gRPC call consists of a bidirectional stream of binary
-// messages, with RPCs of the "non-streaming type" sending only one message in
-// the corresponding direction (the protocol doesn't make any distinction).
-//
-// Each RPC uses a different HTTP2 stream, and thus multiple simultaneous RPCs
-// can be multiplexed transparently on the same TCP connection.
+// Represents a single gRPC remote call.
 @interface GRPCCall : NSObject<GRXWriter>
 
-// These HTTP2 headers will be passed to the server as part of this call. Each
-// HTTP2 header is a name-value pair with string names and either string or binary values.
+// These HTTP headers will be passed to the server as part of this call. Each HTTP header is a
+// name-value pair with string names and either string or binary values.
+//
 // The passed dictionary has to use NSString keys, corresponding to the header names. The
 // value associated to each can be a NSString object or a NSData object. E.g.:
 //
-// call.requestMetadata = @{
-//     @"Authorization": @"Bearer ...",
-//     @"SomeBinaryHeader": someData
-// };
+// call.requestMetadata = @{@"Authorization": @"Bearer ..."};
+//
+// call.requestMetadata[@"SomeBinaryHeader"] = someData;
 //
 // After the call is started, modifying this won't have any effect.
-@property(nonatomic, readwrite) NSMutableDictionary *requestMetadata;
+//
+// For convenience, the property is initialized to an empty NSMutableDictionary, and the setter
+// accepts (and copies) both mutable and immutable dictionaries.
+- (NSMutableDictionary *)requestMetadata; // nonatomic
+- (void)setRequestMetadata:(NSDictionary *)requestMetadata; // nonatomic, copy
 
-// This isn't populated until the first event is delivered to the handler.
+// This dictionary is populated with the HTTP headers received from the server. When the RPC ends,
+// the HTTP trailers received are added to the dictionary too. It has the same structure as the
+// request metadata dictionary.
+//
+// The first time this object calls |writeValue| on the writeable passed to |startWithWriteable|,
+// the |responseMetadata| dictionary already contains the response headers. When it calls
+// |writesFinishedWithError|, the dictionary contains both the response headers and trailers.
 @property(atomic, readonly) NSDictionary *responseMetadata;
 
 // The request writer has to write NSData objects into the provided Writeable. The server will

src/objective-c/GRPCClient/GRPCCall.m

@@ -46,9 +46,9 @@
 #import "private/NSDictionary+GRPC.h"
 #import "private/NSError+GRPC.h"
 
+NSString * const kGRPCStatusMetadataKey = @"io.grpc.StatusMetadataKey";
+
 @interface GRPCCall () <GRXWriteable>
-// Makes it readwrite.
-@property(atomic, strong) NSDictionary *responseMetadata;
 @end
 
 // The following methods of a C gRPC call object aren't reentrant, and thus
@@ -82,6 +82,9 @@
   // correct ordering.
   GRPCDelegateWrapper *_responseWriteable;
   id<GRXWriter> _requestWriter;
+
+  NSMutableDictionary *_requestMetadata;
+  NSMutableDictionary *_responseMetadata;
 }
 
 @synthesize state = _state;
@@ -116,10 +119,27 @@
     _callQueue = dispatch_queue_create("org.grpc.call", NULL);
 
     _requestWriter = requestWriter;
+
+    _requestMetadata = [NSMutableDictionary dictionary];
+    _responseMetadata = [NSMutableDictionary dictionary];
   }
   return self;
 }
 
+#pragma mark Metadata
+
+- (NSMutableDictionary *)requestMetadata {
+  return _requestMetadata;
+}
+
+- (void)setRequestMetadata:(NSDictionary *)requestMetadata {
+  _requestMetadata = [NSMutableDictionary dictionaryWithDictionary:requestMetadata];
+}
+
+- (NSDictionary *)responseMetadata {
+  return _responseMetadata;
+}
+
 #pragma mark Finish
 
 - (void)finishWithError:(NSError *)errorOrNil {
@@ -277,7 +297,7 @@
 // The first one (metadataHandler), when the response headers are received.
 // The second one (completionHandler), whenever the RPC finishes for any reason.
 - (void)invokeCallWithMetadataHandler:(void(^)(NSDictionary *))metadataHandler
-                    completionHandler:(void(^)(NSError *))completionHandler {
+                    completionHandler:(void(^)(NSError *, NSDictionary *))completionHandler {
   // TODO(jcanizales): Add error handlers for async failures
   [_wrappedCall startBatchWithOperations:@[[[GRPCOpRecvMetadata alloc]
                                             initWithHandler:metadataHandler]]];
@@ -287,16 +307,26 @@
 
 - (void)invokeCall {
   __weak GRPCCall *weakSelf = self;
-  [self invokeCallWithMetadataHandler:^(NSDictionary *metadata) {
-    // Response metadata received.
+  [self invokeCallWithMetadataHandler:^(NSDictionary *headers) {
+    // Response headers received.
     GRPCCall *strongSelf = weakSelf;
     if (strongSelf) {
-      strongSelf.responseMetadata = metadata;
+      [strongSelf->_responseMetadata addEntriesFromDictionary:headers];
       [strongSelf startNextRead];
     }
-  } completionHandler:^(NSError *error) {
-    // TODO(jcanizales): Merge HTTP2 trailers into response metadata.
-    [weakSelf finishWithError:error];
+  } completionHandler:^(NSError *error, NSDictionary *trailers) {
+    GRPCCall *strongSelf = weakSelf;
+    if (strongSelf) {
+      [strongSelf->_responseMetadata addEntriesFromDictionary:trailers];
+
+      if (error) {
+        NSMutableDictionary *userInfo =
+            [NSMutableDictionary dictionaryWithDictionary:error.userInfo];
+        userInfo[kGRPCStatusMetadataKey] = strongSelf->_responseMetadata;
+        error = [NSError errorWithDomain:error.domain code:error.code userInfo:userInfo];
+      }
+      [strongSelf finishWithError:error];
+    }
   }];
   // Now that the RPC has been initiated, request writes can start.
   [_requestWriter startWithWriteable:self];

src/objective-c/GRPCClient/private/GRPCWrappedCall.h

@@ -79,7 +79,7 @@ typedef void(^GRPCCompletionHandler)(NSDictionary *);
 
 @interface GRPCOpRecvStatus : NSObject <GRPCOp>
 
-- (instancetype)initWithHandler:(void(^)(NSError *))handler NS_DESIGNATED_INITIALIZER;
+- (instancetype)initWithHandler:(void(^)(NSError *, NSDictionary *))handler NS_DESIGNATED_INITIALIZER;
 
 @end
 

src/objective-c/GRPCClient/private/GRPCWrappedCall.m

@@ -165,9 +165,7 @@
 }
 
 - (void)finish {
-  NSDictionary *metadata = [NSDictionary
-                            grpc_dictionaryFromMetadata:_recvInitialMetadata.metadata
-                            count:_recvInitialMetadata.count];
+  NSDictionary *metadata = [NSDictionary grpc_dictionaryFromMetadataArray:_recvInitialMetadata];
   if (_handler) {
     _handler(metadata);
   }
@@ -209,41 +207,44 @@
 @end
 
 @implementation GRPCOpRecvStatus{
-  void(^_handler)(NSError *);
+  void(^_handler)(NSError *, NSDictionary *);
+  grpc_status_code _statusCode;
+  char *_details;
   size_t _detailsCapacity;
-  grpc_status _status;
+  grpc_metadata_array _metadata;
 }
 
 - (instancetype) init {
   return [self initWithHandler:nil];
 }
 
-- (instancetype) initWithHandler:(void (^)(NSError *))handler {
+- (instancetype) initWithHandler:(void (^)(NSError *, NSDictionary *))handler {
   if (self = [super init]) {
     _handler = handler;
-    grpc_metadata_array_init(&_status.metadata);
+    grpc_metadata_array_init(&_metadata);
   }
   return self;
 }
 
 - (void)getOp:(grpc_op *)op {
   op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
-  op->data.recv_status_on_client.status = &_status.status;
-  op->data.recv_status_on_client.status_details = &_status.details;
+  op->data.recv_status_on_client.status = &_statusCode;
+  op->data.recv_status_on_client.status_details = &_details;
   op->data.recv_status_on_client.status_details_capacity = &_detailsCapacity;
-  op->data.recv_status_on_client.trailing_metadata = &_status.metadata;
+  op->data.recv_status_on_client.trailing_metadata = &_metadata;
 }
 
 - (void)finish {
   if (_handler) {
-    NSError *error = [NSError grpc_errorFromStatus:&_status];
-    _handler(error);
+    NSError *error = [NSError grpc_errorFromStatusCode:_statusCode details:_details];
+    NSDictionary *trailers = [NSDictionary grpc_dictionaryFromMetadataArray:_metadata];
+    _handler(error, trailers);
   }
 }
 
 - (void)dealloc {
-  grpc_metadata_array_destroy(&_status.metadata);
-  gpr_free(_status.details);
+  grpc_metadata_array_destroy(&_metadata);
+  gpr_free(_details);
 }
 
 @end

src/objective-c/GRPCClient/private/NSData+GRPC.m

@@ -55,7 +55,7 @@ static void CopyByteBufferToCharArray(grpc_byte_buffer *buffer, char *array) {
 static grpc_byte_buffer *CopyCharArrayToNewByteBuffer(const char *array,
                                                       size_t length) {
   gpr_slice slice = gpr_slice_from_copied_buffer(array, length);
-  grpc_byte_buffer *buffer = grpc_byte_buffer_create(&slice, 1);
+  grpc_byte_buffer *buffer = grpc_raw_byte_buffer_create(&slice, 1);
   gpr_slice_unref(slice);
   return buffer;
 }
@@ -85,7 +85,7 @@ static grpc_byte_buffer *CopyCharArrayToNewByteBuffer(const char *array,
   // The following implementation is thus not optimal, sometimes requiring two
   // copies (one by self.bytes and another by gpr_slice_from_copied_buffer).
   // If it turns out to be an issue, we can use enumerateByteRangesUsingblock:
-  // to create an array of gpr_slice objects to pass to grpc_byte_buffer_create.
+  // to create an array of gpr_slice objects to pass to grpc_raw_byte_buffer_create.
   // That would make it do exactly one copy, always.
   return CopyCharArrayToNewByteBuffer((const char *)self.bytes, (size_t)self.length);
 }

src/objective-c/GRPCClient/private/NSDictionary+GRPC.h

@@ -35,6 +35,7 @@
 #include <grpc/grpc.h>
 
 @interface NSDictionary (GRPC)
-+ (instancetype)grpc_dictionaryFromMetadata:(struct grpc_metadata *)entries count:(size_t)count;
++ (instancetype)grpc_dictionaryFromMetadataArray:(grpc_metadata_array)array;
++ (instancetype)grpc_dictionaryFromMetadata:(grpc_metadata *)entries count:(size_t)count;
 - (grpc_metadata *)grpc_metadataArray;
 @end

src/objective-c/GRPCClient/private/NSDictionary+GRPC.m

@@ -98,14 +98,18 @@
 #pragma mark Category for metadata arrays
 
 @implementation NSDictionary (GRPC)
++ (instancetype)grpc_dictionaryFromMetadataArray:(grpc_metadata_array)array {
+  return [self grpc_dictionaryFromMetadata:array.metadata count:array.count];
+}
+
 + (instancetype)grpc_dictionaryFromMetadata:(grpc_metadata *)entries count:(size_t)count {
   NSMutableDictionary *metadata = [NSMutableDictionary dictionaryWithCapacity:count];
   for (grpc_metadata *entry = entries; entry < entries + count; entry++) {
     // TODO(jcanizales): Verify in a C library test that it's converting header names to lower case
     // automatically.
     NSString *name = [NSString stringWithCString:entry->key encoding:NSASCIIStringEncoding];
-    if (!name) {
-      // log?
+    if (!name || metadata[name]) {
+      // Log if name is nil?
       continue;
     }
     id value;
@@ -115,10 +119,7 @@
     } else {
       value = [NSString grpc_stringFromMetadataValue:entry];
     }
-    if (!metadata[name]) {
-      metadata[name] = [NSMutableArray array];
-    }
-    [metadata[name] addObject:value];
+    metadata[name] = value;
   }
   return metadata;
 }

src/objective-c/GRPCClient/private/NSError+GRPC.h

@@ -32,6 +32,7 @@
  */
 
 #import <Foundation/Foundation.h>
+#include <grpc/grpc.h>
 
 // TODO(jcanizales): Make the domain string public.
 extern NSString *const kGRPCErrorDomain;
@@ -56,17 +57,8 @@ typedef NS_ENUM(NSInteger, GRPCErrorCode) {
   GRPCErrorCodeDataLoss = 15
 };
 
-// TODO(jcanizales): This is conflating trailing metadata with Status details. Fix it once there's
-// a decision on how to codify Status.
-#include <grpc/grpc.h>
-typedef struct grpc_status {
-    grpc_status_code status;
-    char *details;
-    grpc_metadata_array metadata;
-} grpc_status;
-
 @interface NSError (GRPC)
-// Returns nil if the status is OK. Otherwise, a NSError whose code is one of
-// GRPCErrorCode and whose domain is kGRPCErrorDomain.
-+ (instancetype)grpc_errorFromStatus:(struct grpc_status *)status;
+// Returns nil if the status code is OK. Otherwise, a NSError whose code is one of |GRPCErrorCode|
+// and whose domain is |kGRPCErrorDomain|.
++ (instancetype)grpc_errorFromStatusCode:(grpc_status_code)statusCode details:(char *)details;
 @end