From 7fa9d6f4c83766f9efc7a187527ee3ac242ea842 Mon Sep 17 00:00:00 2001
From: Sree Kuchibhotla <sreek@google.com>
Date: Thu, 28 Jan 2016 17:32:48 -0800
Subject: [PATCH] TryCancel() on ServerContext()

---
 include/grpc++/impl/codegen/server_context.h |  3 +++
 src/cpp/server/server_context.cc             | 16 ++++++++++++----
 2 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/include/grpc++/impl/codegen/server_context.h b/include/grpc++/impl/codegen/server_context.h
index 2af9fdaa34d..868b02882d7 100644
--- a/include/grpc++/impl/codegen/server_context.h
+++ b/include/grpc++/impl/codegen/server_context.h
@@ -105,6 +105,9 @@ class ServerContext {
 
   bool IsCancelled() const;
 
+  // Best-effort API to cancel the call from the server.
+  void TryCancel() const;
+
   const std::multimap<grpc::string_ref, grpc::string_ref>& client_metadata() {
     return client_metadata_;
   }
diff --git a/src/cpp/server/server_context.cc b/src/cpp/server/server_context.cc
index 3732c1f090c..4a5ac5af926 100644
--- a/src/cpp/server/server_context.cc
+++ b/src/cpp/server/server_context.cc
@@ -33,14 +33,14 @@
 
 #include <grpc++/server_context.h>
 
-#include <grpc/compression.h>
-#include <grpc/grpc.h>
-#include <grpc/support/alloc.h>
-#include <grpc/support/log.h>
 #include <grpc++/completion_queue.h>
 #include <grpc++/impl/call.h>
 #include <grpc++/impl/sync.h>
 #include <grpc++/support/time.h>
+#include <grpc/compression.h>
+#include <grpc/grpc.h>
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
 
 #include "src/core/channel/compress_filter.h"
 #include "src/cpp/common/create_auth_context.h"
@@ -173,6 +173,14 @@ void ServerContext::AddTrailingMetadata(const grpc::string& key,
   trailing_metadata_.insert(std::make_pair(key, value));
 }
 
+void ServerContext::TryCancel() const {
+  grpc_call_error err = grpc_call_cancel_with_status(
+      call_, GRPC_STATUS_CANCELLED, "Cancelled on the server side", NULL);
+  if (err != GRPC_CALL_OK) {
+    gpr_log(GPR_INFO, "TryCancel failed with: %d", err);
+  }
+}
+
 bool ServerContext::IsCancelled() const {
   return completion_op_ && completion_op_->CheckCancelled(cq_);
 }