connector.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 GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_CONNECTOR_H
#define GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_CONNECTOR_H
 
#include <grpc/support/port_platform.h>
 
#include <grpc/impl/codegen/grpc_types.h>
 
#include "src/core/lib/channel/channelz.h"
#include "src/core/lib/gprpp/orphanable.h"
#include "src/core/lib/gprpp/ref_counted_ptr.h"
#include "src/core/lib/gprpp/time.h"
#include "src/core/lib/iomgr/closure.h"
#include "src/core/lib/iomgr/error.h"
#include "src/core/lib/iomgr/iomgr_fwd.h"
#include "src/core/lib/iomgr/resolved_address.h"
#include "src/core/lib/transport/transport_fwd.h"
 
namespace grpc_core {
 
// Interface for connection-establishment functionality.
// Each transport that supports client channels (e.g., not inproc) must
// supply an implementation of this.
class SubchannelConnector : public InternallyRefCounted<SubchannelConnector> {
 public:
  struct Args {
    // Address to connect to.
    grpc_resolved_address* address;
    // Set of pollsets interested in this connection.
    grpc_pollset_set* interested_parties;
    // Deadline for connection.
    Timestamp deadline;
    // Channel args to be passed to handshakers and transport.
    const grpc_channel_args* channel_args;
  };
 
  struct Result {
    // The connected transport.
    grpc_transport* transport = nullptr;
    // Channel args to be passed to filters.
    const grpc_channel_args* channel_args = nullptr;
    // Channelz socket node of the connected transport, if any.
    RefCountedPtr<channelz::SocketNode> socket_node;
 
    void Reset() {
      transport = nullptr;
      channel_args = nullptr;
      socket_node.reset();
    }
  };
 
  // Attempts to connect.
  // When complete, populates *result and invokes notify.
  // Only one connection attempt may be in progress at any one time.
  virtual void Connect(const Args& args, Result* result,
                       grpc_closure* notify) = 0;
 
  // Cancels any in-flight connection attempt and shuts down the
  // connector.
  virtual void Shutdown(grpc_error_handle error) = 0;
 
  void Orphan() override {
    Shutdown(GRPC_ERROR_CREATE_FROM_STATIC_STRING("Subchannel disconnected"));
    Unref();
  }
};
 
}  // namespace grpc_core
 
#endif  // GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_CONNECTOR_H