chromium/third_party/grpc/src/include/grpcpp/support/method_handler.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 GRPCPP_SUPPORT_METHOD_HANDLER_H
#define GRPCPP_SUPPORT_METHOD_HANDLER_H

#include <grpc/byte_buffer.h>
#include <grpc/support/log.h>
#include <grpcpp/impl/rpc_service_method.h>
#include <grpcpp/support/byte_buffer.h>
#include <grpcpp/support/sync_stream.h>

namespace grpc {

namespace internal {

// Invoke the method handler, fill in the status, and
// return whether or not we finished safely (without an exception).
// Note that exception handling is 0-cost in most compiler/library
// implementations (except when an exception is actually thrown),
// so this process doesn't require additional overhead in the common case.
// Additionally, we don't need to return if we caught an exception or not;
// the handling is the same in either case.
template <class Callable>
::grpc::Status CatchingFunctionHandler(Callable&& handler) { … }

/// 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) { … }

/// A helper function with reduced templating to do deserializing.

template <class RequestType>
void* UnaryDeserializeHelper(grpc_byte_buffer* req, grpc::Status* status,
                             RequestType* request) { … }

/// A wrapper class of an application provided rpc method handler.
template <class ServiceType, class RequestType, class ResponseType,
          class BaseRequestType = RequestType,
          class BaseResponseType = ResponseType>
class RpcMethodHandler : public grpc::internal::MethodHandler { … };

/// A wrapper class of an application provided client streaming handler.
template <class ServiceType, class RequestType, class ResponseType>
class ClientStreamingHandler : public grpc::internal::MethodHandler { … };

/// A wrapper class of an application provided server streaming handler.
template <class ServiceType, class RequestType, class ResponseType>
class ServerStreamingHandler : public grpc::internal::MethodHandler { … };

/// A wrapper class of an application provided bidi-streaming handler.
/// This also applies to server-streamed implementation of a unary method
/// with the additional requirement that such methods must have done a
/// write for status to be ok
/// Since this is used by more than 1 class, the service is not passed in.
/// Instead, it is expected to be an implicitly-captured argument of func
/// (through bind or something along those lines)
template <class Streamer, bool WriteNeeded>
class TemplatedBidiStreamingHandler : public grpc::internal::MethodHandler { … };

template <class ServiceType, class RequestType, class ResponseType>
class BidiStreamingHandler
    : public TemplatedBidiStreamingHandler<
          ServerReaderWriter<ResponseType, RequestType>, false> { … };

template <class RequestType, class ResponseType>
class StreamedUnaryHandler
    : public TemplatedBidiStreamingHandler<
          ServerUnaryStreamer<RequestType, ResponseType>, true> { … };

template <class RequestType, class ResponseType>
class SplitServerStreamingHandler
    : public TemplatedBidiStreamingHandler<
          ServerSplitStreamer<RequestType, ResponseType>, false> { … };

/// General method handler class for errors that prevent real method use
/// e.g., handle unknown method by returning UNIMPLEMENTED error.
template <grpc::StatusCode code>
class ErrorMethodHandler : public grpc::internal::MethodHandler { … };

UnknownMethodHandler;
ResourceExhaustedHandler;

}  // namespace internal
}  // namespace grpc

#endif  // GRPCPP_SUPPORT_METHOD_HANDLER_H