webkit/fileapi/file_system_usage_cache.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 #ifndef WEBKIT_FILEAPI_FILE_SYSTEM_USAGE_CACHE_H_
   6 #define WEBKIT_FILEAPI_FILE_SYSTEM_USAGE_CACHE_H_
   7
   8 #include "base/basictypes.h"
   9 #include "base/file_path.h"
  10 #include "webkit/fileapi/fileapi_export.h"
  11
  12 namespace fileapi {
  13
  14 class FILEAPI_EXPORT_PRIVATE FileSystemUsageCache {
  15  public:
  16   // Gets the size described in the .usage file even if dirty > 0 or
  17   // is_valid == false.  Returns less than zero if the .usage file is not
  18   // available.
  19   static int64 GetUsage(const FilePath& usage_file_path);
  20
  21   // Gets the dirty count in the .usage file.
  22   // Returns less than zero if the .usage file is not available.
  23   static int32 GetDirty(const FilePath& usage_file_path);
  24
  25   // Increments or decrements the "dirty" entry in the .usage file.
  26   // Returns false if no .usage is available.
  27   static bool IncrementDirty(const FilePath& usage_file_path);
  28   static bool DecrementDirty(const FilePath& usage_file_path);
  29
  30   // Notifies quota system that it needs to recalculate the usage cache of the
  31   // origin.  Returns false if no .usage is available.
  32   static bool Invalidate(const FilePath& usage_file_path);
  33   static bool IsValid(const FilePath& usage_file_path);
  34
  35   // Updates the size described in the .usage file.
  36   static int UpdateUsage(const FilePath& usage_file_path, int64 fs_usage);
  37
  38   // Updates the size described in the .usage file by delta with keeping dirty
  39   // even if dirty > 0.
  40   static int AtomicUpdateUsageByDelta(
  41       const FilePath& usage_file_path, int64 delta);
  42
  43   static bool Exists(const FilePath& usage_file_path);
  44   static bool Delete(const FilePath& usage_file_path);
  45
  46   static const FilePath::CharType kUsageFileName[];
  47   static const char kUsageFileHeader[];
  48   static const int kUsageFileSize;
  49   static const int kUsageFileHeaderSize;
  50
  51  private:
  52   // Read the size, validity and the "dirty" entry described in the .usage file.
  53   // Returns less than zero if no .usage file is available.
  54   static int64 Read(const FilePath& usage_file_path,
  55                     bool* is_valid,
  56                     uint32* dirty);
  57
  58   static int Write(const FilePath& usage_file_path,
  59                    bool is_valid,
  60                    uint32 dirty,
  61                    int64 fs_usage);
  62 };
  63
  64 }  // namespace fileapi
  65
  66 #endif  // WEBKIT_FILEAPI_FILE_SYSTEM_USAGE_CACHE_H_