The C based gRPC (C++, Python, Ruby, Objective-C, PHP, C#) https://grpc.io/
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/*
*
* 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_CHANNEL_H
#define GRPCPP_CHANNEL_H
#include <memory>
#include <grpc/grpc.h>
#include <grpcpp/completion_queue.h>
#include <grpcpp/impl/call.h>
#include <grpcpp/impl/channel_interface.h>
#include <grpcpp/impl/codegen/grpc_library.h>
#include <grpcpp/impl/codegen/sync.h>
#include <grpcpp/support/client_interceptor.h>
#include <grpcpp/support/config.h>
struct grpc_channel;
namespace grpc {
namespace testing {
class ChannelTestPeer;
} // namespace testing
std::shared_ptr<Channel> CreateChannelInternal(
const std::string& host, grpc_channel* c_channel,
std::vector<
std::unique_ptr<experimental::ClientInterceptorFactoryInterface>>
interceptor_creators);
namespace experimental {
/// Resets the channel's connection backoff.
/// TODO(roth): Once we see whether this proves useful, either create a gRFC
/// and change this to be a method of the Channel class, or remove it.
void ChannelResetConnectionBackoff(Channel* channel);
} // namespace experimental
/// Channels represent a connection to an endpoint. Created by \a CreateChannel.
class Channel final : public grpc::ChannelInterface,
public grpc::internal::CallHook,
public std::enable_shared_from_this<Channel>,
private grpc::GrpcLibraryCodegen {
public:
~Channel() override;
/// Get the current channel state. If the channel is in IDLE and
/// \a try_to_connect is set to true, try to connect.
grpc_connectivity_state GetState(bool try_to_connect) override;
/// Returns the LB policy name, or the empty string if not yet available.
std::string GetLoadBalancingPolicyName() const;
/// Returns the service config in JSON form, or the empty string if
/// not available.
std::string GetServiceConfigJSON() const;
private:
template <class InputMessage, class OutputMessage>
friend class grpc::internal::BlockingUnaryCallImpl;
friend class grpc::testing::ChannelTestPeer;
friend void experimental::ChannelResetConnectionBackoff(Channel* channel);
friend std::shared_ptr<Channel> grpc::CreateChannelInternal(
const std::string& host, grpc_channel* c_channel,
std::vector<std::unique_ptr<
grpc::experimental::ClientInterceptorFactoryInterface>>
interceptor_creators);
friend class grpc::internal::InterceptedChannel;
Channel(const std::string& host, grpc_channel* c_channel,
std::vector<std::unique_ptr<
grpc::experimental::ClientInterceptorFactoryInterface>>
interceptor_creators);
grpc::internal::Call CreateCall(const grpc::internal::RpcMethod& method,
grpc::ClientContext* context,
grpc::CompletionQueue* cq) override;
void PerformOpsOnCall(grpc::internal::CallOpSetInterface* ops,
grpc::internal::Call* call) override;
void* RegisterMethod(const char* method) override;
void NotifyOnStateChangeImpl(grpc_connectivity_state last_observed,
gpr_timespec deadline, grpc::CompletionQueue* cq,
void* tag) override;
bool WaitForStateChangeImpl(grpc_connectivity_state last_observed,
gpr_timespec deadline) override;
grpc::CompletionQueue* CallbackCQ() override;
grpc::internal::Call CreateCallInternal(
const grpc::internal::RpcMethod& method, grpc::ClientContext* context,
grpc::CompletionQueue* cq, size_t interceptor_pos) override;
const std::string host_;
grpc_channel* const c_channel_; // owned
// mu_ protects callback_cq_ (the per-channel callbackable completion queue)
grpc::internal::Mutex mu_;
// callback_cq_ references the callbackable completion queue associated
// with this channel (if any). It is set on the first call to CallbackCQ().
// It is _not owned_ by the channel; ownership belongs with its internal
// shutdown callback tag (invoked when the CQ is fully shutdown).
std::atomic<CompletionQueue*> callback_cq_{nullptr};
std::vector<
std::unique_ptr<grpc::experimental::ClientInterceptorFactoryInterface>>
interceptor_creators_;
};
} // namespace grpc
#endif // GRPCPP_CHANNEL_H