Built motion from commit 6a09e18b.|2.6.11

[motion2.git] / legacy-libs / grpc-cloned / deps / grpc / src / core / ext / filters / client_channel / subchannel_interface.h

diff --git a/legacy-libs/grpc-cloned/deps/grpc/src/core/ext/filters/client_channel/subchannel_interface.h b/legacy-libs/grpc-cloned/deps/grpc/src/core/ext/filters/client_channel/subchannel_interface.h
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+/*
+ *
+ * Copyright 2019 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 GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_SUBCHANNEL_INTERFACE_H
+#define GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_SUBCHANNEL_INTERFACE_H
+
+#include <grpc/support/port_platform.h>
+
+#include "src/core/lib/gprpp/ref_counted.h"
+#include "src/core/lib/gprpp/ref_counted_ptr.h"
+
+namespace grpc_core {
+
+// The interface for subchannels that is exposed to LB policy implementations.
+class SubchannelInterface : public RefCounted<SubchannelInterface> {
+ public:
+  class ConnectivityStateWatcherInterface {
+   public:
+    virtual ~ConnectivityStateWatcherInterface() = default;
+
+    // Will be invoked whenever the subchannel's connectivity state
+    // changes.  There will be only one invocation of this method on a
+    // given watcher instance at any given time.
+    virtual void OnConnectivityStateChange(grpc_connectivity_state new_state)
+        GRPC_ABSTRACT;
+
+    // TODO(roth): Remove this as soon as we move to EventManager-based
+    // polling.
+    virtual grpc_pollset_set* interested_parties() GRPC_ABSTRACT;
+
+    GRPC_ABSTRACT_BASE_CLASS
+  };
+
+  template <typename TraceFlagT = TraceFlag>
+  explicit SubchannelInterface(TraceFlagT* trace_flag = nullptr)
+      : RefCounted<SubchannelInterface>(trace_flag) {}
+
+  virtual ~SubchannelInterface() = default;
+
+  // Returns the current connectivity state of the subchannel.
+  virtual grpc_connectivity_state CheckConnectivityState() GRPC_ABSTRACT;
+
+  // Starts watching the subchannel's connectivity state.
+  // The first callback to the watcher will be delivered when the
+  // subchannel's connectivity state becomes a value other than
+  // initial_state, which may happen immediately.
+  // Subsequent callbacks will be delivered as the subchannel's state
+  // changes.
+  // The watcher will be destroyed either when the subchannel is
+  // destroyed or when CancelConnectivityStateWatch() is called.
+  // There can be only one watcher of a given subchannel.  It is not
+  // valid to call this method a second time without first cancelling
+  // the previous watcher using CancelConnectivityStateWatch().
+  virtual void WatchConnectivityState(
+      grpc_connectivity_state initial_state,
+      UniquePtr<ConnectivityStateWatcherInterface> watcher) GRPC_ABSTRACT;
+
+  // Cancels a connectivity state watch.
+  // If the watcher has already been destroyed, this is a no-op.
+  virtual void CancelConnectivityStateWatch(
+      ConnectivityStateWatcherInterface* watcher) GRPC_ABSTRACT;
+
+  // Attempt to connect to the backend.  Has no effect if already connected.
+  // If the subchannel is currently in backoff delay due to a previously
+  // failed attempt, the new connection attempt will not start until the
+  // backoff delay has elapsed.
+  virtual void AttemptToConnect() GRPC_ABSTRACT;
+
+  // Resets the subchannel's connection backoff state.  If AttemptToConnect()
+  // has been called since the subchannel entered TRANSIENT_FAILURE state,
+  // starts a new connection attempt immediately; otherwise, a new connection
+  // attempt will be started as soon as AttemptToConnect() is called.
+  virtual void ResetBackoff() GRPC_ABSTRACT;
+
+  // TODO(roth): Need a better non-grpc-specific abstraction here.
+  virtual const grpc_channel_args* channel_args() GRPC_ABSTRACT;
+
+  GRPC_ABSTRACT_BASE_CLASS
+};
+
+}  // namespace grpc_core
+
+#endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_SUBCHANNEL_INTERFACE_H */