text: //  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.
  //
  // Copyright (c) 2011 The LevelDB Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file. See the AUTHORS file for names of contributors.
  //
  #pragma once
  #include "vidardb/env.h"
  
  namespace vidardb {
  
  class TableCache;
  class VersionStorageInfo;
  class VersionEdit;
  struct FileMetaData;
  class InternalStats;
  
  // A helper class so we can efficiently apply a whole sequence
  // of edits to a particular state without creating intermediate
  // Versions that contain full copies of the intermediate state.
  class VersionBuilder {
   public:
    VersionBuilder(const EnvOptions& env_options, TableCache* table_cache,
                   VersionStorageInfo* base_vstorage, Logger* info_log = nullptr);
    ~VersionBuilder();
    void CheckConsistency(VersionStorageInfo* vstorage);
    void CheckConsistencyForDeletes(VersionEdit* edit, uint64_t number,
                                    int level);
    void Apply(VersionEdit* edit);
    void SaveTo(VersionStorageInfo* vstorage);
    void LoadTableHandlers(InternalStats* internal_stats, int max_threads = 1);
    void MaybeAddFile(VersionStorageInfo* vstorage, int level, FileMetaData* f);
  
   private:
    class Rep;
    Rep* rep_;
  };
  
  extern bool NewestFirstBySeqNo(FileMetaData* a, FileMetaData* b);
  }  // namespace vidardb
  