Merge pull request #24494 from vjpai/server_code_size

Reduce template use in sync server unary calls

include/grpcpp/impl/codegen/byte_buffer.h

@@ -40,8 +40,9 @@ template <class RequestType, class ResponseType>
 class CallbackUnaryHandler;
 template <class RequestType, class ResponseType>
 class CallbackServerStreamingHandler;
-template <class ServiceType, class RequestType, class ResponseType>
-class RpcMethodHandler;
+template <class RequestType>
+void* UnaryDeserializeHelper(grpc_call*, grpc_byte_buffer*, ::grpc::Status*,
+                             RequestType*);
 template <class ServiceType, class RequestType, class ResponseType>
 class ServerStreamingHandler;
 template <::grpc::StatusCode code>
@@ -162,8 +163,9 @@ class ByteBuffer final {
   template <class R>
   friend class internal::CallOpRecvMessage;
   friend class internal::CallOpGenericRecvMessage;
-  template <class ServiceType, class RequestType, class ResponseType>
-  friend class internal::RpcMethodHandler;
+  template <class RequestType>
+  friend void* internal::UnaryDeserializeHelper(grpc_call*, grpc_byte_buffer*,
+                                                ::grpc::Status*, RequestType*);
   template <class ServiceType, class RequestType, class ResponseType>
   friend class internal::ServerStreamingHandler;
   template <class RequestType, class ResponseType>

include/grpcpp/impl/codegen/completion_queue.h

@@ -38,6 +38,7 @@
 #include <grpcpp/impl/codegen/completion_queue_tag.h>
 #include <grpcpp/impl/codegen/core_codegen_interface.h>
 #include <grpcpp/impl/codegen/grpc_library.h>
+#include <grpcpp/impl/codegen/rpc_service_method.h>
 #include <grpcpp/impl/codegen/status.h>
 #include <grpcpp/impl/codegen/sync.h>
 #include <grpcpp/impl/codegen/time.h>
@@ -59,7 +60,12 @@ namespace internal {
 template <class W, class R>
 class ServerReaderWriterBody;
 
-template <class ServiceType, class RequestType, class ResponseType>
+template <class ResponseType>
+void UnaryRunHandlerHelper(
+    const ::grpc::internal::MethodHandler::HandlerParameter&, ResponseType*,
+    ::grpc::Status&);
+template <class ServiceType, class RequestType, class ResponseType,
+          class BaseRequestType, class BaseResponseType>
 class RpcMethodHandler;
 template <class ServiceType, class RequestType, class ResponseType>
 class ClientStreamingHandler;
@@ -265,8 +271,10 @@ class CompletionQueue : private ::grpc::GrpcLibraryCodegen {
   friend class ::grpc::ServerWriter;
   template <class W, class R>
   friend class ::grpc::internal::ServerReaderWriterBody;
-  template <class ServiceType, class RequestType, class ResponseType>
-  friend class ::grpc::internal::RpcMethodHandler;
+  template <class ResponseType>
+  friend void ::grpc::internal::UnaryRunHandlerHelper(
+      const ::grpc::internal::MethodHandler::HandlerParameter&, ResponseType*,
+      ::grpc::Status&);
   template <class ServiceType, class RequestType, class ResponseType>
   friend class ::grpc::internal::ClientStreamingHandler;
   template <class ServiceType, class RequestType, class ResponseType>

include/grpcpp/impl/codegen/method_handler.h

@@ -49,8 +49,52 @@ template <class Callable>
 #endif  // GRPC_ALLOW_EXCEPTIONS
 }
 
+/// A helper function with reduced templating to do the common work needed to
+/// actually send the server response. Uses non-const parameter for Status since
+/// this should only ever be called from the end of the RunHandler method.
+
+template <class ResponseType>
+void UnaryRunHandlerHelper(const MethodHandler::HandlerParameter& param,
+                           ResponseType* rsp, ::grpc::Status& status) {
+  GPR_CODEGEN_ASSERT(!param.server_context->sent_initial_metadata_);
+  ::grpc::internal::CallOpSet<::grpc::internal::CallOpSendInitialMetadata,
+                              ::grpc::internal::CallOpSendMessage,
+                              ::grpc::internal::CallOpServerSendStatus>
+      ops;
+  ops.SendInitialMetadata(&param.server_context->initial_metadata_,
+                          param.server_context->initial_metadata_flags());
+  if (param.server_context->compression_level_set()) {
+    ops.set_compression_level(param.server_context->compression_level());
+  }
+  if (status.ok()) {
+    status = ops.SendMessagePtr(rsp);
+  }
+  ops.ServerSendStatus(&param.server_context->trailing_metadata_, status);
+  param.call->PerformOps(&ops);
+  param.call->cq()->Pluck(&ops);
+}
+
+/// A helper function with reduced templating to do deserializing.
+
+template <class RequestType>
+void* UnaryDeserializeHelper(grpc_call* call, grpc_byte_buffer* req,
+                             ::grpc::Status* status, RequestType* request) {
+  ::grpc::ByteBuffer buf;
+  buf.set_buffer(req);
+  *status = ::grpc::SerializationTraits<RequestType>::Deserialize(
+      &buf, static_cast<RequestType*>(request));
+  buf.Release();
+  if (status->ok()) {
+    return request;
+  }
+  request->~RequestType();
+  return nullptr;
+}
+
 /// A wrapper class of an application provided rpc method handler.
-template <class ServiceType, class RequestType, class ResponseType>
+template <class ServiceType, class RequestType, class ResponseType,
+          class BaseRequestType = RequestType,
+          class BaseResponseType = ResponseType>
 class RpcMethodHandler : public ::grpc::internal::MethodHandler {
  public:
   RpcMethodHandler(
@@ -71,40 +115,16 @@ class RpcMethodHandler : public ::grpc::internal::MethodHandler {
       });
       static_cast<RequestType*>(param.request)->~RequestType();
     }
-
-    GPR_CODEGEN_ASSERT(!param.server_context->sent_initial_metadata_);
-    ::grpc::internal::CallOpSet<::grpc::internal::CallOpSendInitialMetadata,
-                                ::grpc::internal::CallOpSendMessage,
-                                ::grpc::internal::CallOpServerSendStatus>
-        ops;
-    ops.SendInitialMetadata(&param.server_context->initial_metadata_,
-                            param.server_context->initial_metadata_flags());
-    if (param.server_context->compression_level_set()) {
-      ops.set_compression_level(param.server_context->compression_level());
-    }
-    if (status.ok()) {
-      status = ops.SendMessagePtr(&rsp);
-    }
-    ops.ServerSendStatus(&param.server_context->trailing_metadata_, status);
-    param.call->PerformOps(&ops);
-    param.call->cq()->Pluck(&ops);
+    UnaryRunHandlerHelper(param, static_cast<BaseResponseType*>(&rsp), status);
   }
 
   void* Deserialize(grpc_call* call, grpc_byte_buffer* req,
                     ::grpc::Status* status, void** /*handler_data*/) final {
-    ::grpc::ByteBuffer buf;
-    buf.set_buffer(req);
     auto* request =
         new (::grpc::g_core_codegen_interface->grpc_call_arena_alloc(
-            call, sizeof(RequestType))) RequestType();
-    *status =
-        ::grpc::SerializationTraits<RequestType>::Deserialize(&buf, request);
-    buf.Release();
-    if (status->ok()) {
-      return request;
-    }
-    request->~RequestType();
-    return nullptr;
+            call, sizeof(RequestType))) RequestType;
+    return UnaryDeserializeHelper(call, req, status,
+                                  static_cast<BaseRequestType*>(request));
   }
 
  private:

include/grpcpp/impl/codegen/server_context.h

@@ -37,6 +37,7 @@
 #include <grpcpp/impl/codegen/create_auth_context.h>
 #include <grpcpp/impl/codegen/message_allocator.h>
 #include <grpcpp/impl/codegen/metadata_map.h>
+#include <grpcpp/impl/codegen/rpc_service_method.h>
 #include <grpcpp/impl/codegen/security/auth_context.h>
 #include <grpcpp/impl/codegen/server_callback.h>
 #include <grpcpp/impl/codegen/server_interceptor.h>
@@ -75,7 +76,11 @@ template <class RequestType, class ResponseType>
 class CallbackBidiHandler;
 template <class ServiceType, class RequestType, class ResponseType>
 class ClientStreamingHandler;
-template <class ServiceType, class RequestType, class ResponseType>
+template <class ResponseType>
+void UnaryRunHandlerHelper(const MethodHandler::HandlerParameter&,
+                           ResponseType*, Status&);
+template <class ServiceType, class RequestType, class ResponseType,
+          class BaseRequestType, class BaseResponseType>
 class RpcMethodHandler;
 template <class Base>
 class FinishOnlyReactor;
@@ -355,7 +360,12 @@ class ServerContextBase {
   friend class ::grpc::ServerWriter;
   template <class W, class R>
   friend class ::grpc::internal::ServerReaderWriterBody;
-  template <class ServiceType, class RequestType, class ResponseType>
+  template <class ResponseType>
+  friend void ::grpc::internal::UnaryRunHandlerHelper(
+      const internal::MethodHandler::HandlerParameter& param, ResponseType* rsp,
+      Status& status);
+  template <class ServiceType, class RequestType, class ResponseType,
+            class BaseRequestType, class BaseResponseType>
   friend class ::grpc::internal::RpcMethodHandler;
   template <class ServiceType, class RequestType, class ResponseType>
   friend class ::grpc::internal::ClientStreamingHandler;

src/compiler/cpp_generator.cc

@@ -2216,8 +2216,8 @@ void PrintSourceService(grpc_generator::Printer* printer,
           "    $prefix$$Service$_method_names[$Idx$],\n"
           "    ::grpc::internal::RpcMethod::NORMAL_RPC,\n"
           "    new ::grpc::internal::RpcMethodHandler< $ns$$Service$::Service, "
-          "$Request$, "
-          "$Response$>(\n"
+          "$Request$, $Response$, ::grpc::protobuf::MessageLite, "
+          "::grpc::protobuf::MessageLite>(\n"
           "        []($ns$$Service$::Service* service,\n"
           "           ::grpc::ServerContext* ctx,\n"
           "           const $Request$* req,\n"