Merge github.com:grpc/grpc into idempotent

2 files changed, 92 insertions, 8 deletions

diff --git a/src/cpp/README.md b/src/cpp/README.md
index baeba08315..83d37aa2ed 100644
--- a/src/cpp/README.md
+++ b/src/cpp/README.md
@@ -6,3 +6,77 @@ This directory contains source code for C++ implementation of gRPC.
 #Status
 
 Beta
+
+#Pre-requisites
+
+##Linux
+
+```sh
+ $ [sudo] apt-get install build-essential autoconf libtool
+```
+
+##Mac OSX
+
+For a Mac system, git is not available by default. You will first need to
+install Xcode from the Mac AppStore and then run the following command from a
+terminal:
+
+```sh
+ $ [sudo] xcode-select --install
+```
+
+##Protoc
+
+By default gRPC uses [protocol buffers](https://github.com/google/protobuf),
+you will need the `protoc` compiler to generate stub server and client code.
+
+If you compile gRPC from source, as described below, this also installs the
+`protoc` compiler.
+
+If it hasn't been installed, you can run the following commands to install it.
+
+```sh
+$ cd grpc/third_party/protobuf
+$ sudo make install   # 'make' should have been run by core grpc
+```
+
+Alternatively, you can download `protoc` binaries from
+[the protocol buffers Github repository](https://github.com/google/protobuf/releases).
+
+#Installation
+
+Currently to install gRPC for C++, you need to build from source as described
+below.
+
+#Build from Source
+
+```sh
+ $ git clone https://github.com/grpc/grpc.git
+ $ cd grpc
+ $ git submodule update --init
+ $ make
+ $ [sudo] make install
+```
+
+#Documentation
+
+You can find out how to build and run our simplest gRPC C++ example in our
+[C++ quick start](https://github.com/grpc/grpc/tree/{{ site.data.config.grpc_release_branch }}/examples/cpp).
+
+For more detailed documentation on using gRPC in C++ , see our main
+documentation site at [grpc.io](http://grpc.io), specifically:
+
+* [Overview](http://www.grpc.io/docs/): An introduction to gRPC with a simple
+  Hello World example in all our supported languages, including C++.
+* [gRPC Basics - C++](http://www.grpc.io/docs/tutorials/basic/c.html):
+  A tutorial that steps you through creating a simple gRPC C++ example
+  application.
+* [Asynchronous Basics - C++](http://www.grpc.io/docs/tutorials/async/helloasync-cpp.html):
+  A tutorial that shows you how to use gRPC C++'s asynchronous/non-blocking
+  APIs.
+
+
+# Examples
+
+Code examples for gRPC C++ live in this repository's
+[examples/cpp](https://github.com/grpc/grpc/tree/{{ site.data.config.grpc_release_branch }}/examples/cpp) directory.
diff --git a/src/cpp/server/server_context.cc b/src/cpp/server/server_context.cc
index e205a1969b..eb49b21037 100644
--- a/src/cpp/server/server_context.cc
+++ b/src/cpp/server/server_context.cc
@@ -62,7 +62,11 @@ class ServerContext::CompletionOp GRPC_FINAL : public CallOpSetInterface {
   void FillOps(grpc_op* ops, size_t* nops) GRPC_OVERRIDE;
   bool FinalizeResult(void** tag, bool* status) GRPC_OVERRIDE;
 
-  bool CheckCancelled(CompletionQueue* cq);
+  bool CheckCancelled(CompletionQueue* cq) {
+    cq->TryPluck(this);
+    return CheckCancelledNoPluck();
+  }
+  bool CheckCancelledAsync() { return CheckCancelledNoPluck(); }
 
   void set_tag(void* tag) {
     has_tag_ = true;
@@ -72,6 +76,11 @@ class ServerContext::CompletionOp GRPC_FINAL : public CallOpSetInterface {
   void Unref();
 
  private:
+  bool CheckCancelledNoPluck() {
+    grpc::lock_guard<grpc::mutex> g(mu_);
+    return finalized_ ? (cancelled_ != 0) : false;
+  }
+
   bool has_tag_;
   void* tag_;
   grpc::mutex mu_;
@@ -88,12 +97,6 @@ void ServerContext::CompletionOp::Unref() {
   }
 }
 
-bool ServerContext::CompletionOp::CheckCancelled(CompletionQueue* cq) {
-  cq->TryPluck(this);
-  grpc::lock_guard<grpc::mutex> g(mu_);
-  return finalized_ ? cancelled_ != 0 : false;
-}
-
 void ServerContext::CompletionOp::FillOps(grpc_op* ops, size_t* nops) {
   ops->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
   ops->data.recv_close_on_server.cancelled = &cancelled_;
@@ -182,7 +185,14 @@ void ServerContext::TryCancel() const {
 }
 
 bool ServerContext::IsCancelled() const {
-  return completion_op_ && completion_op_->CheckCancelled(cq_);
+  if (has_notify_when_done_tag_) {
+    // when using async API, but the result is only valid
+    // if the tag has already been delivered at the completion queue
+    return completion_op_ && completion_op_->CheckCancelledAsync();
+  } else {
+    // when using sync API
+    return completion_op_ && completion_op_->CheckCancelled(cq_);
+  }
 }
 
 void ServerContext::set_compression_level(grpc_compression_level level) {