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Pods/gRPC-C++/include/grpcpp/channel.h

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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/grpc_library.h>
+#include <grpcpp/impl/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::internal::GrpcLibrary {
+ 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