block_bitmaps_v3.h revision a1401311d1ab56c4ed0a474bd38c108f75cb0cd9 
1// Copyright (c) 2012 The Chromium 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.
4
5// See net/disk_cache/disk_cache.h for the public interface.
6
7#ifndef NET_DISK_CACHE_BLOCKFILE_BLOCK_BITMAPS_V3_H_
8#define NET_DISK_CACHE_BLOCKFILE_BLOCK_BITMAPS_V3_H_
9
10#include "base/files/file_path.h"
11#include "net/base/net_export.h"
12#include "net/disk_cache/blockfile/addr.h"
13#include "net/disk_cache/blockfile/block_files.h"
14
15namespace disk_cache {
16
17class BackendImplV3;
18
19// This class is the interface in the v3 disk cache to the set of files holding
20// cached data that is small enough to not be efficiently stored in a dedicated
21// file (i.e. < kMaxBlockSize). It is primarily used to allocate and free
22// regions in those files used to store data.
23class NET_EXPORT_PRIVATE BlockBitmaps {
24 public:
25  BlockBitmaps();
26  ~BlockBitmaps();
27
28  void Init(const BlockFilesBitmaps& bitmaps);
29
30  // Creates a new entry on a block file. block_type indicates the size of block
31  // to be used (as defined on cache_addr.h), block_count is the number of
32  // blocks to allocate, and block_address is the address of the new entry.
33  bool CreateBlock(FileType block_type, int block_count, Addr* block_address);
34
35  // Removes an entry from the block files.
36  void DeleteBlock(Addr address);
37
38  // Releases the internal bitmaps. The cache is being purged.
39  void Clear();
40
41  // Sends UMA stats.
42  void ReportStats();
43
44  // Returns true if the blocks pointed by a given address are currently used.
45  // This method is only intended for debugging.
46  bool IsValid(Addr address);
47
48 private:
49  // Returns the header number that stores a given address.
50  int GetHeaderNumber(Addr address);
51
52  // Returns the appropriate header to use for a new block.
53  int HeaderNumberForNewBlock(FileType block_type, int block_count);
54
55  // Retrieves stats for the given file index.
56  void GetFileStats(int index, int* used_count, int* load);
57
58  BlockFilesBitmaps bitmaps_;
59
60  DISALLOW_COPY_AND_ASSIGN(BlockBitmaps);
61};
62
63}  // namespace disk_cache
64
65#endif  // NET_DISK_CACHE_BLOCKFILE_BLOCK_BITMAPS_V3_H_
66