3 * Copyright 2015 gRPC authors.
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at
9 * http://www.apache.org/licenses/LICENSE-2.0
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
19 #ifndef GRPCPP_CHANNEL_IMPL_H
20 #define GRPCPP_CHANNEL_IMPL_H
25 #include <grpc/grpc.h>
26 #include <grpcpp/impl/call.h>
27 #include <grpcpp/impl/codegen/channel_interface.h>
28 #include <grpcpp/impl/codegen/client_interceptor.h>
29 #include <grpcpp/impl/codegen/completion_queue.h>
30 #include <grpcpp/impl/codegen/config.h>
31 #include <grpcpp/impl/codegen/grpc_library.h>
32 #include <grpcpp/impl/codegen/sync.h>
38 std::shared_ptr<::grpc_impl::Channel> CreateChannelInternal(
39 const grpc::string& host, grpc_channel* c_channel,
41 std::unique_ptr<experimental::ClientInterceptorFactoryInterface>>
42 interceptor_creators);
46 namespace experimental {
47 /// Resets the channel's connection backoff.
48 /// TODO(roth): Once we see whether this proves useful, either create a gRFC
49 /// and change this to be a method of the Channel class, or remove it.
50 void ChannelResetConnectionBackoff(Channel* channel);
51 } // namespace experimental
53 /// Channels represent a connection to an endpoint. Created by \a CreateChannel.
54 class Channel final : public ::grpc::ChannelInterface,
55 public ::grpc::internal::CallHook,
56 public std::enable_shared_from_this<Channel>,
57 private ::grpc::GrpcLibraryCodegen {
61 /// Get the current channel state. If the channel is in IDLE and
62 /// \a try_to_connect is set to true, try to connect.
63 grpc_connectivity_state GetState(bool try_to_connect) override;
65 /// Returns the LB policy name, or the empty string if not yet available.
66 grpc::string GetLoadBalancingPolicyName() const;
68 /// Returns the service config in JSON form, or the empty string if
70 grpc::string GetServiceConfigJSON() const;
73 template <class InputMessage, class OutputMessage>
74 friend class ::grpc::internal::BlockingUnaryCallImpl;
75 friend void experimental::ChannelResetConnectionBackoff(Channel* channel);
76 friend std::shared_ptr<Channel> grpc::CreateChannelInternal(
77 const grpc::string& host, grpc_channel* c_channel,
78 std::vector<std::unique_ptr<
79 ::grpc::experimental::ClientInterceptorFactoryInterface>>
80 interceptor_creators);
81 friend class ::grpc::internal::InterceptedChannel;
82 Channel(const grpc::string& host, grpc_channel* c_channel,
83 std::vector<std::unique_ptr<
84 ::grpc::experimental::ClientInterceptorFactoryInterface>>
85 interceptor_creators);
87 ::grpc::internal::Call CreateCall(const ::grpc::internal::RpcMethod& method,
88 ::grpc::ClientContext* context,
89 ::grpc::CompletionQueue* cq) override;
90 void PerformOpsOnCall(::grpc::internal::CallOpSetInterface* ops,
91 ::grpc::internal::Call* call) override;
92 void* RegisterMethod(const char* method) override;
94 void NotifyOnStateChangeImpl(grpc_connectivity_state last_observed,
95 gpr_timespec deadline,
96 ::grpc::CompletionQueue* cq, void* tag) override;
97 bool WaitForStateChangeImpl(grpc_connectivity_state last_observed,
98 gpr_timespec deadline) override;
100 ::grpc::CompletionQueue* CallbackCQ() override;
102 ::grpc::internal::Call CreateCallInternal(
103 const ::grpc::internal::RpcMethod& method, ::grpc::ClientContext* context,
104 ::grpc::CompletionQueue* cq, size_t interceptor_pos) override;
106 const grpc::string host_;
107 grpc_channel* const c_channel_; // owned
109 // mu_ protects callback_cq_ (the per-channel callbackable completion queue)
110 grpc::internal::Mutex mu_;
112 // callback_cq_ references the callbackable completion queue associated
113 // with this channel (if any). It is set on the first call to CallbackCQ().
114 // It is _not owned_ by the channel; ownership belongs with its internal
115 // shutdown callback tag (invoked when the CQ is fully shutdown).
116 ::grpc::CompletionQueue* callback_cq_ = nullptr;
119 std::unique_ptr<::grpc::experimental::ClientInterceptorFactoryInterface>>
120 interceptor_creators_;
123 } // namespace grpc_impl
125 #endif // GRPCPP_CHANNEL_IMPL_H