grpc/include/grpc++/impl/codegen/client_unary_call.h

/*
 *
 * Copyright 2015 gRPC authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

#ifndef GRPCXX_IMPL_CODEGEN_CLIENT_UNARY_CALL_H
#define GRPCXX_IMPL_CODEGEN_CLIENT_UNARY_CALL_H

#include <grpc++/impl/codegen/call.h>
#include <grpc++/impl/codegen/channel_interface.h>
#include <grpc++/impl/codegen/config.h>
#include <grpc++/impl/codegen/core_codegen_interface.h>
#include <grpc++/impl/codegen/status.h>

namespace grpc {

class Channel;
class ClientContext;
class CompletionQueue;
class RpcMethod;

/// Wrapper that performs a blocking unary call
template <class InputMessage, class OutputMessage>
Status BlockingUnaryCall(ChannelInterface* channel, const RpcMethod& method,
                         ClientContext* context, const InputMessage& request,
                         OutputMessage* result) {
  CompletionQueue cq(grpc_completion_queue_attributes{
      GRPC_CQ_CURRENT_VERSION, GRPC_CQ_PLUCK,
      GRPC_CQ_DEFAULT_POLLING});  // Pluckable completion queue
  Call call(channel->CreateCall(method, context, &cq));
  CallOpSet<CallOpSendInitialMetadata, CallOpSendMessage,
            CallOpRecvInitialMetadata, CallOpRecvMessage<OutputMessage>,
            CallOpClientSendClose, CallOpClientRecvStatus>
      ops;
  Status status = ops.SendMessage(request);
  if (!status.ok()) {
    return status;
  }
  ops.SendInitialMetadata(context->send_initial_metadata_,
                          context->initial_metadata_flags());
  ops.RecvInitialMetadata(context);
  ops.RecvMessage(result);
  ops.ClientSendClose();
  ops.ClientRecvStatus(context, &status);
  call.PerformOps(&ops);
  if (cq.Pluck(&ops)) {
    if (!ops.got_message && status.ok()) {
      return Status(StatusCode::UNIMPLEMENTED,
                    "No message returned for unary request");
    }
  } else {
    GPR_CODEGEN_ASSERT(!status.ok());
  }
  return status;
}

}  // namespace grpc

#endif  // GRPCXX_IMPL_CODEGEN_CLIENT_UNARY_CALL_H