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Pods/gRPC-C++/include/grpcpp/impl/channel_interface.h

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+//
+//
+// Copyright 2016 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_CHANNEL_INTERFACE_H
+#define GRPCPP_IMPL_CHANNEL_INTERFACE_H
+
+#include <grpc/impl/connectivity_state.h>
+#include <grpcpp/impl/call.h>
+#include <grpcpp/support/status.h>
+#include <grpcpp/support/time.h>
+
+namespace grpc {
+template <class R>
+class ClientReader;
+template <class W>
+class ClientWriter;
+template <class W, class R>
+class ClientReaderWriter;
+namespace internal {
+template <class InputMessage, class OutputMessage>
+class CallbackUnaryCallImpl;
+template <class R>
+class ClientAsyncReaderFactory;
+template <class W>
+class ClientAsyncWriterFactory;
+template <class W, class R>
+class ClientAsyncReaderWriterFactory;
+class ClientAsyncResponseReaderHelper;
+template <class W, class R>
+class ClientCallbackReaderWriterFactory;
+template <class R>
+class ClientCallbackReaderFactory;
+template <class W>
+class ClientCallbackWriterFactory;
+class ClientCallbackUnaryFactory;
+}  // namespace internal
+
+class ChannelInterface;
+class ClientContext;
+class CompletionQueue;
+
+namespace experimental {
+class DelegatingChannel;
+}
+
+namespace internal {
+class Call;
+class CallOpSetInterface;
+class RpcMethod;
+class InterceptedChannel;
+template <class InputMessage, class OutputMessage>
+class BlockingUnaryCallImpl;
+}  // namespace internal
+
+/// Codegen interface for \a grpc::Channel.
+class ChannelInterface {
+ public:
+  virtual ~ChannelInterface() {}
+  /// Get the current channel state. If the channel is in IDLE and
+  /// \a try_to_connect is set to true, try to connect.
+  virtual grpc_connectivity_state GetState(bool try_to_connect) = 0;
+
+  /// Return the \a tag on \a cq when the channel state is changed or \a
+  /// deadline expires. \a GetState needs to called to get the current state.
+  template <typename T>
+  void NotifyOnStateChange(grpc_connectivity_state last_observed, T deadline,
+                           grpc::CompletionQueue* cq, void* tag) {
+    TimePoint<T> deadline_tp(deadline);
+    NotifyOnStateChangeImpl(last_observed, deadline_tp.raw_time(), cq, tag);
+  }
+
+  /// Blocking wait for channel state change or \a deadline expiration.
+  /// \a GetState needs to called to get the current state.
+  template <typename T>
+  bool WaitForStateChange(grpc_connectivity_state last_observed, T deadline) {
+    TimePoint<T> deadline_tp(deadline);
+    return WaitForStateChangeImpl(last_observed, deadline_tp.raw_time());
+  }
+
+  /// Wait for this channel to be connected
+  template <typename T>
+  bool WaitForConnected(T deadline) {
+    grpc_connectivity_state state;
+    while ((state = GetState(true)) != GRPC_CHANNEL_READY) {
+      if (!WaitForStateChange(state, deadline)) return false;
+    }
+    return true;
+  }
+
+ private:
+  template <class R>
+  friend class grpc::ClientReader;
+  template <class W>
+  friend class grpc::ClientWriter;
+  template <class W, class R>
+  friend class grpc::ClientReaderWriter;
+  template <class R>
+  friend class grpc::internal::ClientAsyncReaderFactory;
+  template <class W>
+  friend class grpc::internal::ClientAsyncWriterFactory;
+  template <class W, class R>
+  friend class grpc::internal::ClientAsyncReaderWriterFactory;
+  friend class grpc::internal::ClientAsyncResponseReaderHelper;
+  template <class W, class R>
+  friend class grpc::internal::ClientCallbackReaderWriterFactory;
+  template <class R>
+  friend class grpc::internal::ClientCallbackReaderFactory;
+  template <class W>
+  friend class grpc::internal::ClientCallbackWriterFactory;
+  friend class grpc::internal::ClientCallbackUnaryFactory;
+  template <class InputMessage, class OutputMessage>
+  friend class grpc::internal::BlockingUnaryCallImpl;
+  template <class InputMessage, class OutputMessage>
+  friend class grpc::internal::CallbackUnaryCallImpl;
+  friend class grpc::internal::RpcMethod;
+  friend class grpc::experimental::DelegatingChannel;
+  friend class grpc::internal::InterceptedChannel;
+  virtual internal::Call CreateCall(const internal::RpcMethod& method,
+                                    grpc::ClientContext* context,
+                                    grpc::CompletionQueue* cq) = 0;
+  virtual void PerformOpsOnCall(internal::CallOpSetInterface* ops,
+                                internal::Call* call) = 0;
+  virtual void* RegisterMethod(const char* method) = 0;
+  virtual void NotifyOnStateChangeImpl(grpc_connectivity_state last_observed,
+                                       gpr_timespec deadline,
+                                       grpc::CompletionQueue* cq,
+                                       void* tag) = 0;
+  virtual bool WaitForStateChangeImpl(grpc_connectivity_state last_observed,
+                                      gpr_timespec deadline) = 0;
+
+  // EXPERIMENTAL
+  // This is needed to keep codegen_test_minimal happy. InterceptedChannel needs
+  // to make use of this but can't directly call Channel's implementation
+  // because of the test.
+  // Returns an empty Call object (rather than being pure) since this is a new
+  // method and adding a new pure method to an interface would be a breaking
+  // change (even though this is private and non-API)
+  virtual internal::Call CreateCallInternal(
+      const internal::RpcMethod& /*method*/, grpc::ClientContext* /*context*/,
+      grpc::CompletionQueue* /*cq*/, size_t /*interceptor_pos*/) {
+    return internal::Call();
+  }
+
+  // A method to get the callbackable completion queue associated with this
+  // channel. If the return value is nullptr, this channel doesn't support
+  // callback operations.
+  // TODO(vjpai): Consider a better default like using a global CQ
+  // Returns nullptr (rather than being pure) since this is a post-1.0 method
+  // and adding a new pure method to an interface would be a breaking change
+  // (even though this is private and non-API)
+  virtual grpc::CompletionQueue* CallbackCQ() { return nullptr; }
+};
+}  // namespace grpc
+
+#endif  // GRPCPP_IMPL_CHANNEL_INTERFACE_H