3 files changed, 75 insertions, 14 deletions

diff --git a/src/cpp/client/channel.cc b/src/cpp/client/channel.cc
index ee143d68a0..af7366eb01 100644
--- a/src/cpp/client/channel.cc
+++ b/src/cpp/client/channel.cc
@@ -48,6 +48,7 @@
 #include <grpc++/impl/call.h>
 #include <grpc++/impl/rpc_method.h>
 #include <grpc++/status.h>
+#include <grpc++/time.h>
 
 namespace grpc {
 
@@ -61,16 +62,18 @@ Channel::~Channel() { grpc_channel_destroy(c_channel_); }
 Call Channel::CreateCall(const RpcMethod& method, ClientContext* context,
                          CompletionQueue* cq) {
   const char* host_str = host_.empty() ? NULL : host_.c_str();
-  auto c_call =
-      method.channel_tag() && context->authority().empty()
-          ? grpc_channel_create_registered_call(c_channel_, cq->cq(),
-                                                method.channel_tag(),
-                                                context->raw_deadline())
-          : grpc_channel_create_call(c_channel_, cq->cq(), method.name(),
-                                     context->authority().empty()
-                                         ? host_str
-                                         : context->authority().c_str(),
-                                     context->raw_deadline());
+  auto c_call = method.channel_tag() && context->authority().empty()
+                    ? grpc_channel_create_registered_call(
+                          c_channel_, context->propagate_from_call_,
+                          context->propagation_options_.c_bitmask(), cq->cq(),
+                          method.channel_tag(), context->raw_deadline())
+                    : grpc_channel_create_call(
+                          c_channel_, context->propagate_from_call_,
+                          context->propagation_options_.c_bitmask(), cq->cq(),
+                          method.name(), context->authority().empty()
+                                             ? host_str
+                                             : context->authority().c_str(),
+                          context->raw_deadline());
   grpc_census_call_set_context(c_call, context->census_context());
   GRPC_TIMER_MARK(GRPC_PTAG_CPP_CALL_CREATED, c_call);
   context->set_call(c_call, shared_from_this());
@@ -93,4 +96,43 @@ void* Channel::RegisterMethod(const char* method) {
                                     host_.empty() ? NULL : host_.c_str());
 }
 
+grpc_connectivity_state Channel::GetState(bool try_to_connect) {
+  return grpc_channel_check_connectivity_state(c_channel_, try_to_connect);
+}
+
+namespace {
+class TagSaver GRPC_FINAL : public CompletionQueueTag {
+ public:
+  explicit TagSaver(void* tag) : tag_(tag) {}
+  ~TagSaver() GRPC_OVERRIDE {}
+  bool FinalizeResult(void** tag, bool* status) GRPC_OVERRIDE {
+    *tag = tag_;
+    delete this;
+    return true;
+  }
+ private:
+  void* tag_;
+};
+
+}  // namespace
+
+void Channel::NotifyOnStateChangeImpl(grpc_connectivity_state last_observed,
+                                      gpr_timespec deadline,
+                                      CompletionQueue* cq, void* tag) {
+  TagSaver* tag_saver = new TagSaver(tag);
+  grpc_channel_watch_connectivity_state(c_channel_, last_observed, deadline,
+                                        cq->cq(), tag_saver);
+}
+
+bool Channel::WaitForStateChangeImpl(grpc_connectivity_state last_observed,
+                                     gpr_timespec deadline) {
+  CompletionQueue cq;
+  bool ok = false;
+  void* tag = NULL;
+  NotifyOnStateChangeImpl(last_observed, deadline, &cq, NULL);
+  cq.Next(&tag, &ok);
+  GPR_ASSERT(tag == NULL);
+  return ok;
+}
+
 }  // namespace grpc
diff --git a/src/cpp/client/channel.h b/src/cpp/client/channel.h
index 8660146856..cb8e8d98d2 100644
--- a/src/cpp/client/channel.h
+++ b/src/cpp/client/channel.h
@@ -56,13 +56,22 @@ class Channel GRPC_FINAL : public GrpcLibrary, public ChannelInterface {
   Channel(const grpc::string& host, grpc_channel* c_channel);
   ~Channel() GRPC_OVERRIDE;
 
-  virtual void* RegisterMethod(const char* method) GRPC_OVERRIDE;
-  virtual Call CreateCall(const RpcMethod& method, ClientContext* context,
+  void* RegisterMethod(const char* method) GRPC_OVERRIDE;
+  Call CreateCall(const RpcMethod& method, ClientContext* context,
                           CompletionQueue* cq) GRPC_OVERRIDE;
-  virtual void PerformOpsOnCall(CallOpSetInterface* ops,
+  void PerformOpsOnCall(CallOpSetInterface* ops,
                                 Call* call) GRPC_OVERRIDE;
 
+  grpc_connectivity_state GetState(bool try_to_connect) GRPC_OVERRIDE;
+
  private:
+  void NotifyOnStateChangeImpl(grpc_connectivity_state last_observed,
+                               gpr_timespec deadline, CompletionQueue* cq,
+                               void* tag) GRPC_OVERRIDE;
+
+  bool WaitForStateChangeImpl(grpc_connectivity_state last_observed,
+                              gpr_timespec deadline) GRPC_OVERRIDE;
+
   const grpc::string host_;
   grpc_channel* const c_channel_;  // owned
 };
diff --git a/src/cpp/client/client_context.cc b/src/cpp/client/client_context.cc
index c38d0c1df6..1ed2d38961 100644
--- a/src/cpp/client/client_context.cc
+++ b/src/cpp/client/client_context.cc
@@ -37,6 +37,7 @@
 #include <grpc/support/alloc.h>
 #include <grpc/support/string_util.h>
 #include <grpc++/credentials.h>
+#include <grpc++/server_context.h>
 #include <grpc++/time.h>
 
 #include "src/core/channel/compress_filter.h"
@@ -48,7 +49,8 @@ ClientContext::ClientContext()
     : initial_metadata_received_(false),
       call_(nullptr),
       cq_(nullptr),
-      deadline_(gpr_inf_future(GPR_CLOCK_REALTIME)) {}
+      deadline_(gpr_inf_future(GPR_CLOCK_REALTIME)),
+      propagate_from_call_(nullptr) {}
 
 ClientContext::~ClientContext() {
   if (call_) {
@@ -64,6 +66,14 @@ ClientContext::~ClientContext() {
   }
 }
 
+std::unique_ptr<ClientContext> ClientContext::FromServerContext(
+    const ServerContext& context, PropagationOptions options) {
+  std::unique_ptr<ClientContext> ctx(new ClientContext);
+  ctx->propagate_from_call_ = context.call_;
+  ctx->propagation_options_ = options;
+  return ctx;
+}
+
 void ClientContext::AddMetadata(const grpc::string& meta_key,
                                 const grpc::string& meta_value) {
   send_initial_metadata_.insert(std::make_pair(meta_key, meta_value));