| 123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103 | /* * * 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 GRPCPP_IMPL_CODEGEN_CLIENT_UNARY_CALL_H#define GRPCPP_IMPL_CODEGEN_CLIENT_UNARY_CALL_H#include <grpcpp/impl/codegen/call.h>#include <grpcpp/impl/codegen/call_op_set.h>#include <grpcpp/impl/codegen/channel_interface.h>#include <grpcpp/impl/codegen/config.h>#include <grpcpp/impl/codegen/core_codegen_interface.h>#include <grpcpp/impl/codegen/status.h>namespace grpc {class ClientContext;namespace internal {class RpcMethod;/// Wrapper that performs a blocking unary call. May optionally specify the base/// class of the Request and Response so that the internal calls and structures/// below this may be based on those base classes and thus achieve code reuse/// across different RPCs (e.g., for protobuf, MessageLite would be a base/// class).template <class InputMessage, class OutputMessage,          class BaseInputMessage = InputMessage,          class BaseOutputMessage = OutputMessage>Status BlockingUnaryCall(ChannelInterface* channel, const RpcMethod& method,                         grpc::ClientContext* context,                         const InputMessage& request, OutputMessage* result) {  static_assert(std::is_base_of<BaseInputMessage, InputMessage>::value,                "Invalid input message specification");  static_assert(std::is_base_of<BaseOutputMessage, OutputMessage>::value,                "Invalid output message specification");  return BlockingUnaryCallImpl<BaseInputMessage, BaseOutputMessage>(             channel, method, context, request, result)      .status();}template <class InputMessage, class OutputMessage>class BlockingUnaryCallImpl { public:  BlockingUnaryCallImpl(ChannelInterface* channel, const RpcMethod& method,                        grpc::ClientContext* context,                        const InputMessage& request, OutputMessage* result) {    ::grpc::CompletionQueue cq(grpc_completion_queue_attributes{        GRPC_CQ_CURRENT_VERSION, GRPC_CQ_PLUCK, GRPC_CQ_DEFAULT_POLLING,        nullptr});  // Pluckable completion queue    ::grpc::internal::Call call(channel->CreateCall(method, context, &cq));    CallOpSet<CallOpSendInitialMetadata, CallOpSendMessage,              CallOpRecvInitialMetadata, CallOpRecvMessage<OutputMessage>,              CallOpClientSendClose, CallOpClientRecvStatus>        ops;    status_ = ops.SendMessagePtr(&request);    if (!status_.ok()) {      return;    }    ops.SendInitialMetadata(&context->send_initial_metadata_,                            context->initial_metadata_flags());    ops.RecvInitialMetadata(context);    ops.RecvMessage(result);    ops.AllowNoMessage();    ops.ClientSendClose();    ops.ClientRecvStatus(context, &status_);    call.PerformOps(&ops);    cq.Pluck(&ops);    // Some of the ops might fail. If the ops fail in the core layer, status    // would reflect the error. But, if the ops fail in the C++ layer, the    // status would still be the same as the one returned by gRPC Core. This can    // happen if deserialization of the message fails.    // TODO(yashykt): If deserialization fails, but the status received is OK,    // then it might be a good idea to change the status to something better    // than StatusCode::UNIMPLEMENTED to reflect this.    if (!ops.got_message && status_.ok()) {      status_ = Status(StatusCode::UNIMPLEMENTED,                       "No message returned for unary request");    }  }  Status status() { return status_; } private:  Status status_;};}  // namespace internal}  // namespace grpc#endif  // GRPCPP_IMPL_CODEGEN_CLIENT_UNARY_CALL_H
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