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

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#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