Reduce code paths

include/grpcpp/impl/codegen/call_op_set.h

@@ -330,6 +330,7 @@ class CallOpSendMessage {
   }
   void FinishOp(bool* status) {
     if (msg_ == nullptr && !send_buf_.Valid()) return;
+    send_buf_.Clear();
     if (hijacked_ && failed_send_) {
       // Hijacking interceptor failed this Op
       *status = false;
@@ -378,9 +379,33 @@ class CallOpSendMessage {
 template <class M>
 Status CallOpSendMessage::SendMessage(const M& message, WriteOptions options) {
   write_options_ = options;
+  // Serialize immediately since we do not have access to the message pointer
+  bool own_buf;
+  // TODO(vjpai): Remove the void below when possible
+  // The void in the template parameter below should not be needed
+  // (since it should be implicit) but is needed due to an observed
+  // difference in behavior between clang and gcc for certain internal users
+  Status result = SerializationTraits<M, void>::Serialize(
+      message, send_buf_.bbuf_ptr(), &own_buf);
+  if (!own_buf) {
+    send_buf_.Duplicate();
+  }
+  return result;
+}
+
+template <class M>
+Status CallOpSendMessage::SendMessage(const M& message) {
+  return SendMessage(message, WriteOptions());
+}
+
+template <class M>
+Status CallOpSendMessage::SendMessagePtr(const M* message,
+                                         WriteOptions options) {
+  msg_ = message;
+  write_options_ = options;
+  // Store the serializer for later since we have access to the message
   serializer_ = [this](const void* message) {
     bool own_buf;
-    send_buf_.Clear();
     // TODO(vjpai): Remove the void below when possible
     // The void in the template parameter below should not be needed
     // (since it should be implicit) but is needed due to an observed
@@ -392,31 +417,12 @@ Status CallOpSendMessage::SendMessage(const M& message, WriteOptions options) {
     }
     return result;
   };
-  // Serialize immediately only if we do not have access to the message pointer
-  if (msg_ == nullptr) {
-    Status result = serializer_(&message);
-    serializer_ = nullptr;
-    return result;
-  }
   return Status();
 }
 
-template <class M>
-Status CallOpSendMessage::SendMessage(const M& message) {
-  return SendMessage(message, WriteOptions());
-}
-
-template <class M>
-Status CallOpSendMessage::SendMessagePtr(const M* message,
-                                         WriteOptions options) {
-  msg_ = message;
-  return SendMessage(*message, options);
-}
-
 template <class M>
 Status CallOpSendMessage::SendMessagePtr(const M* message) {
-  msg_ = message;
-  return SendMessage(*message, WriteOptions());
+  return SendMessagePtr(message, WriteOptions());
 }
 
 template <class R>