net/disk_cache/v3/block_bitmaps.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_BLOCK_FILES_H_
   8 #define NET_DISK_CACHE_BLOCK_FILES_H_
   9
  10 #include <vector>
  11
  12 #include "base/files/file_path.h"
  13 #include "base/gtest_prod_util.h"
  14 #include "base/memory/scoped_ptr.h"
  15 #include "net/base/net_export.h"
  16 #include "net/disk_cache/addr.h"
  17 #include "net/disk_cache/mapped_file.h"
  18
  19 namespace disk_cache {
  20
  21 // This class handles the set of block-files open by the disk cache.
  22 class NET_EXPORT_PRIVATE BlockFiles {
  23  public:
  24   explicit BlockFiles(const base::FilePath& path);
  25   ~BlockFiles();
  26
  27   // Performs the object initialization. create_files indicates if the backing
  28   // files should be created or just open.
  29   bool Init(bool create_files);
  30
  31   // Creates a new entry on a block file. block_type indicates the size of block
  32   // to be used (as defined on cache_addr.h), block_count is the number of
  33   // blocks to allocate, and block_address is the address of the new entry.
  34   bool CreateBlock(FileType block_type, int block_count, Addr* block_address);
  35
  36   // Removes an entry from the block files. If deep is true, the storage is zero
  37   // filled; otherwise the entry is removed but the data is not altered (must be
  38   // already zeroed).
  39   void DeleteBlock(Addr address, bool deep);
  40
  41   // Close all the files and set the internal state to be initializad again. The
  42   // cache is being purged.
  43   void CloseFiles();
  44
  45   // Sends UMA stats.
  46   void ReportStats();
  47
  48   // Returns true if the blocks pointed by a given address are currently used.
  49   // This method is only intended for debugging.
  50   bool IsValid(Addr address);
  51
  52  private:
  53   // Returns the file that stores a given address.
  54   MappedFile* GetFile(Addr address);
  55
  56   // Attemp to grow this file. Fails if the file cannot be extended anymore.
  57   bool GrowBlockFile(MappedFile* file, BlockFileHeader* header);
  58
  59   // Returns the appropriate file to use for a new block.
  60   MappedFile* FileForNewBlock(FileType block_type, int block_count);
  61
  62   // Restores the header of a potentially inconsistent file.
  63   bool FixBlockFileHeader(MappedFile* file);
  64
  65   // Retrieves stats for the given file index.
  66   void GetFileStats(int index, int* used_count, int* load);
  67
  68   bool init_;
  69
  70   DISALLOW_COPY_AND_ASSIGN(BlockFiles);
  71 };
  72
  73 }  // namespace disk_cache
  74
  75 #endif  // NET_DISK_CACHE_BLOCK_FILES_H_