src/core/lib/surface/lame_client.h

/*
 *
 * 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 GRPC_CORE_LIB_SURFACE_LAME_CLIENT_H
#define GRPC_CORE_LIB_SURFACE_LAME_CLIENT_H

#include <grpc/support/port_platform.h>

#include <memory>

#include "absl/base/thread_annotations.h"
#include "absl/status/status.h"
#include "absl/status/statusor.h"

#include <grpc/impl/codegen/grpc_types.h>

#include "src/core/lib/channel/channel_args.h"
#include "src/core/lib/channel/channel_fwd.h"
#include "src/core/lib/channel/promise_based_filter.h"
#include "src/core/lib/gprpp/sync.h"
#include "src/core/lib/iomgr/error.h"
#include "src/core/lib/promise/arena_promise.h"
#include "src/core/lib/transport/connectivity_state.h"
#include "src/core/lib/transport/transport.h"

namespace grpc_core {
// Does NOT take ownership of error.
grpc_arg MakeLameClientErrorArg(grpc_error_handle* error);

// This filter becomes the entire channel stack for a channel that fails to be
// created. Every call returns failure.
class LameClientFilter : public ChannelFilter {
 public:
  static const grpc_channel_filter kFilter;

  static absl::StatusOr<LameClientFilter> Create(
      ChannelArgs args, ChannelFilter::Args filter_args);
  ArenaPromise<ServerMetadataHandle> MakeCallPromise(
      CallArgs call_args, NextPromiseFactory next_promise_factory) override;
  bool StartTransportOp(grpc_transport_op*) override;
  bool GetChannelInfo(const grpc_channel_info*) override;

 private:
  explicit LameClientFilter(absl::Status error);

  absl::Status error_;
  struct State {
    State();
    Mutex mu;
    ConnectivityStateTracker state_tracker ABSL_GUARDED_BY(mu);
  };
  std::unique_ptr<State> state_;
};
}  // namespace grpc_core

#endif /* GRPC_CORE_LIB_SURFACE_LAME_CLIENT_H */