net/disk_cache/blockfile/block_bitmaps_v3.h

   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
  15 namespace disk_cache {
  16
  17 class 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.
  23 class 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_