YugabyteDB (2.13.0.0-b42, bfc6a6643e7399ac8a0e81d06a3ee6d6571b33ab)

//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.

//  This source code is licensed under the BSD-style license found in the

//  LICENSE file in the root directory of this source tree. An additional grant

//  of patent rights can be found in the PATENTS file in the same directory.

//

// The following only applies to changes made to this file as part of YugaByte development.

//

// Portions Copyright (c) YugaByte, Inc.

//

// 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 <atomic>

#include <mutex>

#include <set>

namespace rocksdb {

class ColumnFamilyData;

// Unless otherwise noted, all methods on FlushScheduler should be called

// only with the DB mutex held or from a single-threaded recovery context.

class FlushScheduler {

 public:

  FlushScheduler() : head_(nullptr) {}

  // May be called from multiple threads at once, but not concurrent with

  // any other method calls on this instance

  void ScheduleFlush(ColumnFamilyData* cfd);

  // Removes and returns Ref()-ed column family. Client needs to Unref().

  // Filters column families that have been dropped.

  ColumnFamilyData* TakeNextColumnFamily();

  bool Empty();

  void Clear();

 private:

  struct Node {

    ColumnFamilyData* column_family;

    Node* next;

  };

  std::atomic<Node*> head_;

#ifndef NDEBUG

  std::mutex checking_mutex_;

  std::set<ColumnFamilyData*> checking_set_;

#endif  // NDEBUG

};

}  // namespace rocksdb