From 2d04dd827ce66a54ea8ddc6c691f9c028833fd56 Mon Sep 17 00:00:00 2001
From: Vijay Pai <vpai@google.com>
Date: Wed, 27 Jul 2016 11:35:56 -0700
Subject: [PATCH] Change API for next message size to allow a bool return value
 for failure cases.

---
 include/grpc++/impl/codegen/fc_unary.h    |  5 ++++-
 include/grpc++/impl/codegen/sync_stream.h | 22 +++++++++++++++++-----
 test/cpp/end2end/hybrid_end2end_test.cc   |  4 +++-
 test/cpp/end2end/mock_test.cc             | 10 ++++++++--
 4 files changed, 32 insertions(+), 9 deletions(-)

diff --git a/include/grpc++/impl/codegen/fc_unary.h b/include/grpc++/impl/codegen/fc_unary.h
index 22e40ab02e5..768443912b8 100644
--- a/include/grpc++/impl/codegen/fc_unary.h
+++ b/include/grpc++/impl/codegen/fc_unary.h
@@ -56,7 +56,10 @@ template <class RequestType, class ResponseType>
  public:
  FCUnary(Call* call, ServerContext* ctx): call_(call), ctx_(ctx), read_done_(false), write_done_(false) {}
   ~FCUnary() {}
-  uint32_t NextMessageSize() {return call_->max_message_size();}
+  bool NextMessageSize(uint32_t *sz) {
+    *sz = call_->max_message_size();
+    return true;
+  }
   bool Read(RequestType *request) {
     if (read_done_) {
       return false;      
diff --git a/include/grpc++/impl/codegen/sync_stream.h b/include/grpc++/impl/codegen/sync_stream.h
index 0afa8b6aa49..930c72056c2 100644
--- a/include/grpc++/impl/codegen/sync_stream.h
+++ b/include/grpc++/impl/codegen/sync_stream.h
@@ -71,7 +71,7 @@ class ReaderInterface {
   virtual ~ReaderInterface() {}
 
   /// Upper bound on the next message size available for reading on this stream
-  virtual uint32_t NextMessageSize() = 0;
+  virtual bool NextMessageSize(uint32_t *sz) = 0;
 
   /// Blocking read a message and parse to \a msg. Returns \a true on success.
   /// This is thread-safe with respect to \a Write or \WritesDone methods on
@@ -151,7 +151,10 @@ class ClientReader GRPC_FINAL : public ClientReaderInterface<R> {
     cq_.Pluck(&ops);  /// status ignored
   }
 
-  uint32_t NextMessageSize() GRPC_OVERRIDE {return call_.max_message_size();}
+  bool NextMessageSize(uint32_t *sz) GRPC_OVERRIDE {
+    *sz = call_.max_message_size();
+    return true;
+  }
 
   bool Read(R* msg) GRPC_OVERRIDE {
     CallOpSet<CallOpRecvInitialMetadata, CallOpRecvMessage<R>> ops;
@@ -298,7 +301,10 @@ class ClientReaderWriter GRPC_FINAL : public ClientReaderWriterInterface<W, R> {
     cq_.Pluck(&ops);  // status ignored
   }
 
-  uint32_t NextMessageSize() GRPC_OVERRIDE {return call_.max_message_size();}
+  bool NextMessageSize(uint32_t *sz) GRPC_OVERRIDE {
+    *sz = call_.max_message_size();
+    return true;
+  }
 
   bool Read(R* msg) GRPC_OVERRIDE {
     CallOpSet<CallOpRecvInitialMetadata, CallOpRecvMessage<R>> ops;
@@ -359,7 +365,10 @@ class ServerReader GRPC_FINAL : public ReaderInterface<R> {
     call_->cq()->Pluck(&ops);
   }
 
-  uint32_t NextMessageSize() GRPC_OVERRIDE {return call_->max_message_size();}
+  bool NextMessageSize(uint32_t *sz) GRPC_OVERRIDE {
+    *sz = call_->max_message_size();
+    return true;
+  }
 
   bool Read(R* msg) GRPC_OVERRIDE {
     CallOpSet<CallOpRecvMessage<R>> ops;
@@ -427,7 +436,10 @@ class ServerReaderWriter GRPC_FINAL : public WriterInterface<W>,
     call_->cq()->Pluck(&ops);
   }
 
-  uint32_t NextMessageSize() GRPC_OVERRIDE {return call_->max_message_size();}
+  bool NextMessageSize(uint32_t *sz) GRPC_OVERRIDE {
+    *sz = call_->max_message_size();
+    return true;
+  }
 
   bool Read(R* msg) GRPC_OVERRIDE {
     CallOpSet<CallOpRecvMessage<R>> ops;
diff --git a/test/cpp/end2end/hybrid_end2end_test.cc b/test/cpp/end2end/hybrid_end2end_test.cc
index 699cf49b260..b80010e8031 100644
--- a/test/cpp/end2end/hybrid_end2end_test.cc
+++ b/test/cpp/end2end/hybrid_end2end_test.cc
@@ -426,7 +426,9 @@ public:
   Status FCEcho(ServerContext* context, FCUnary<EchoRequest,EchoResponse>* fc_unary) GRPC_OVERRIDE {
     EchoRequest req;
     EchoResponse resp;
-    gpr_log(GPR_INFO, "FC Unary Next Message Size is %u", fc_unary->NextMessageSize());
+    uint32_t next_msg_sz;
+    fc_unary->NextMessageSize(&next_msg_sz);
+    gpr_log(GPR_INFO, "FC Unary Next Message Size is %u", next_msg_sz);
     GPR_ASSERT(fc_unary->Read(&req));
     resp.set_message(req.message() + "_dup");
     GPR_ASSERT(fc_unary->Write(resp));
diff --git a/test/cpp/end2end/mock_test.cc b/test/cpp/end2end/mock_test.cc
index 744a7cd9eb9..40526271221 100644
--- a/test/cpp/end2end/mock_test.cc
+++ b/test/cpp/end2end/mock_test.cc
@@ -64,7 +64,10 @@ class MockClientReaderWriter GRPC_FINAL
     : public ClientReaderWriterInterface<W, R> {
  public:
   void WaitForInitialMetadata() GRPC_OVERRIDE {}
-  uint32_t NextMessageSize() GRPC_OVERRIDE {return UINT_MAX;}
+  bool NextMessageSize(uint32_t* sz) GRPC_OVERRIDE {
+    *sz = UINT_MAX;
+    return true;
+  }
   bool Read(R* msg) GRPC_OVERRIDE { return true; }
   bool Write(const W& msg) GRPC_OVERRIDE { return true; }
   bool WritesDone() GRPC_OVERRIDE { return true; }
@@ -76,7 +79,10 @@ class MockClientReaderWriter<EchoRequest, EchoResponse> GRPC_FINAL
  public:
   MockClientReaderWriter() : writes_done_(false) {}
   void WaitForInitialMetadata() GRPC_OVERRIDE {}
-  uint32_t NextMessageSize() GRPC_OVERRIDE {return UINT_MAX;}
+  bool NextMessageSize(uint32_t* sz) GRPC_OVERRIDE {
+    *sz = UINT_MAX;
+    return true;
+  }
   bool Read(EchoResponse* msg) GRPC_OVERRIDE {
     if (writes_done_) return false;
     msg->set_message(last_message_);