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  1. // Copyright (c) 2011 The LevelDB Authors. All rights reserved.
  2. // Use of this source code is governed by a BSD-style license that can be
  3. // found in the LICENSE file. See the AUTHORS file for names of contributors.
  4. //
  5. // Thread-safe (provides internal synchronization)
  6. #ifndef STORAGE_LEVELDB_DB_TABLE_CACHE_H_
  7. #define STORAGE_LEVELDB_DB_TABLE_CACHE_H_
  8. #include <string>
  9. #include <stdint.h>
  10. #include "db/dbformat.h"
  11. #include "leveldb/cache.h"
  12. #include "leveldb/table.h"
  13. #include "port/port.h"
  14. namespace leveldb {
  15. class Env;
  16. class TableCache {
  17. public:
  18. TableCache(const std::string& dbname, const Options* options, int entries);
  19. ~TableCache();
  20. // Return an iterator for the specified file number (the corresponding
  21. // file length must be exactly "file_size" bytes). If "tableptr" is
  22. // non-NULL, also sets "*tableptr" to point to the Table object
  23. // underlying the returned iterator, or NULL if no Table object underlies
  24. // the returned iterator. The returned "*tableptr" object is owned by
  25. // the cache and should not be deleted, and is valid for as long as the
  26. // returned iterator is live.
  27. Iterator* NewIterator(const ReadOptions& options,
  28. uint64_t file_number,
  29. uint64_t file_size,
  30. Table** tableptr = NULL);
  31. // If a seek to internal key "k" in specified file finds an entry,
  32. // call (*handle_result)(arg, found_key, found_value).
  33. Status Get(const ReadOptions& options,
  34. uint64_t file_number,
  35. uint64_t file_size,
  36. const Slice& k,
  37. void* arg,
  38. void (*handle_result)(void*, const Slice&, const Slice&));
  39. // Evict any entry for the specified file number
  40. void Evict(uint64_t file_number);
  41. private:
  42. Env* const env_;
  43. const std::string dbname_;
  44. const Options* options_;
  45. Cache* cache_;
  46. Status FindTable(uint64_t file_number, uint64_t file_size, Cache::Handle**);
  47. };
  48. } // namespace leveldb
  49. #endif // STORAGE_LEVELDB_DB_TABLE_CACHE_H_