Inside Bitcoin

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
7#ifndef STORAGE_LEVELDB_DB_TABLE_CACHE_H_
8#define STORAGE_LEVELDB_DB_TABLE_CACHE_H_
9
10#include <stdint.h>
11
12#include <string>
13
14#include "db/dbformat.h"
15#include "leveldb/cache.h"
16#include "leveldb/table.h"
17#include "port/port.h"
18
19namespace leveldb {
20
21class Env;
22
23class TableCache {
24 public:
25  TableCache(const std::string& dbname, const Options& options, int entries);
26  ~TableCache();
27
28  // Return an iterator for the specified file number (the corresponding
29  // file length must be exactly "file_size" bytes).  If "tableptr" is
30  // non-null, also sets "*tableptr" to point to the Table object
31  // underlying the returned iterator, or to nullptr if no Table object
32  // underlies the returned iterator.  The returned "*tableptr" object is owned
33  // by the cache and should not be deleted, and is valid for as long as the
34  // returned iterator is live.
35  Iterator* NewIterator(const ReadOptions& options, uint64_t file_number,
36                        uint64_t file_size, Table** tableptr = nullptr);
37
38  // If a seek to internal key "k" in specified file finds an entry,
39  // call (*handle_result)(arg, found_key, found_value).
40  Status Get(const ReadOptions& options, uint64_t file_number,
41             uint64_t file_size, const Slice& k, void* arg,
42             void (*handle_result)(void*, const Slice&, const Slice&));
43
44  // Evict any entry for the specified file number
45  void Evict(uint64_t file_number);
46
47 private:
48  Status FindTable(uint64_t file_number, uint64_t file_size, Cache::Handle**);
49
50  Env* const env_;
51  const std::string dbname_;
52  const Options& options_;
53  Cache* cache_;
54};
55
56}  // namespace leveldb
57
58#endif  // STORAGE_LEVELDB_DB_TABLE_CACHE_H_
59