text: //   Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
  //
  // 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.
  
  #pragma once
  
  #include <memory>
  #include <string>
  #include <vector>
  
  #include "paddle/fluid/framework/details/op_handle_base.h"
  #include "paddle/fluid/framework/feed_fetch_type.h"
  #include "paddle/fluid/framework/op_registry.h"
  #include "paddle/fluid/framework/scope.h"
  #include "paddle/fluid/platform/device_context.h"
  
  namespace paddle {
  namespace framework {
  namespace details {
  
  // **NOTE**: fetch_barrier op is special it outputs all recved variables on
  // all places if there are multiple places, must init with
  // multiple dev_ctxes_ !!!!
  
  struct FetchBarrierOpHandle : public OpHandleBase {
   public:
    FetchBarrierOpHandle(ir::Node *node, const std::vector<Scope *> &local_scopes,
                         const std::vector<platform::Place> &places);
  
    bool IsMultiDeviceTransfer() override;
  
    std::string Name() const override;
  
   protected:
    void RunImpl() override;
  
    std::vector<Scope *> GetLocalScopes() override { return local_scopes_; }
  
    bool NeedWait(VarHandleBase *in_var) override;
  
   private:
    std::unique_ptr<OperatorBase> op_;
    std::vector<Scope *> local_scopes_;
    std::vector<platform::Place> places_;
    Scope *run_scope_;
    platform::Place place_;
  
    bool is_lock_and_record_event_free_{false};
  };
  
  }  // namespace details
  }  // namespace framework
  }  // namespace paddle
  