text: //  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
  //  This source code is licensed under both the GPLv2 (found in the
  //  COPYING file in the root directory) and Apache 2.0 License
  //  (found in the LICENSE.Apache file in the root directory).
  
  #pragma once
  #ifndef ROCKSDB_LITE
  #include <atomic>
  #include <memory>
  
  #include "rocksdb/table_properties.h"
  
  namespace ROCKSDB_NAMESPACE {
  
  // A factory of a table property collector that marks a SST
  // file as need-compaction when it observe at least "D" deletion
  // entries in any "N" consecutive entires.
  class CompactOnDeletionCollectorFactory
      : public TablePropertiesCollectorFactory {
   public:
    virtual ~CompactOnDeletionCollectorFactory() {}
  
    virtual TablePropertiesCollector* CreateTablePropertiesCollector(
        TablePropertiesCollectorFactory::Context context) override;
  
    // Change the value of sliding_window_size "N"
    // Setting it to 0 disables the delete triggered compaction
    void SetWindowSize(size_t sliding_window_size) {
      sliding_window_size_.store(sliding_window_size);
    }
  
    // Change the value of deletion_trigger "D"
    void SetDeletionTrigger(size_t deletion_trigger) {
      deletion_trigger_.store(deletion_trigger);
    }
  
    virtual const char* Name() const override {
      return "CompactOnDeletionCollector";
    }
  
   private:
    friend std::shared_ptr<CompactOnDeletionCollectorFactory>
    NewCompactOnDeletionCollectorFactory(size_t sliding_window_size,
                                         size_t deletion_trigger);
    // A factory of a table property collector that marks a SST
    // file as need-compaction when it observe at least "D" deletion
    // entries in any "N" consecutive entires.
    //
    // @param sliding_window_size "N"
    // @param deletion_trigger "D"
    CompactOnDeletionCollectorFactory(size_t sliding_window_size,
                                      size_t deletion_trigger)
        : sliding_window_size_(sliding_window_size),
          deletion_trigger_(deletion_trigger) {}
  
    std::atomic<size_t> sliding_window_size_;
    std::atomic<size_t> deletion_trigger_;
  };
  
  // Creates a factory of a table property collector that marks a SST
  // file as need-compaction when it observe at least "D" deletion
  // entries in any "N" consecutive entires.
  //
  // @param sliding_window_size "N". Note that this number will be
  //     round up to the smallest multiple of 128 that is no less
  //     than the specified size.
  // @param deletion_trigger "D".  Note that even when "N" is changed,
  //     the specified number for "D" will not be changed.
  extern std::shared_ptr<CompactOnDeletionCollectorFactory>
  NewCompactOnDeletionCollectorFactory(size_t sliding_window_size,
                                       size_t deletion_trigger);
  }  // namespace ROCKSDB_NAMESPACE
  
  #endif  // !ROCKSDB_LITE
  