storage/browser/fileapi/quota/open_file_handle.h

   1 // Copyright 2013 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 STORAGE_BROWSER_FILEAPI_QUOTA_OPEN_FILE_HANDLE_H_
   6 #define STORAGE_BROWSER_FILEAPI_QUOTA_OPEN_FILE_HANDLE_H_
   7
   8 #include "base/basictypes.h"
   9 #include "base/memory/ref_counted.h"
  10 #include "base/memory/weak_ptr.h"
  11 #include "storage/browser/storage_browser_export.h"
  12
  13 namespace base {
  14 class FilePath;
  15 }
  16
  17 namespace storage {
  18
  19 class QuotaReservation;
  20 class OpenFileHandleContext;
  21 class QuotaReservationBuffer;
  22
  23 // Represents an open file like a file descriptor.
  24 // This should be alive while a consumer keeps a file opened and should be
  25 // deleted when the plugin closes the file.
  26 class STORAGE_EXPORT OpenFileHandle {
  27  public:
  28   ~OpenFileHandle();
  29
  30   // Updates cached file size and consumes quota for that.
  31   // Both this and AddAppendModeWriteAmount should be called for each modified
  32   // file before calling QuotaReservation::RefreshQuota and before closing the
  33   // file.
  34   void UpdateMaxWrittenOffset(int64 offset);
  35
  36   // Notifies that |amount| of data is written to the file in append mode, and
  37   // consumes quota for that.
  38   // Both this and UpdateMaxWrittenOffset should be called for each modified
  39   // file before calling QuotaReservation::RefreshQuota and before closing the
  40   // file.
  41   void AddAppendModeWriteAmount(int64 amount);
  42
  43   // Returns the estimated file size for the quota consumption calculation.
  44   // The client must consume its reserved quota when it writes data to the file
  45   // beyond the estimated file size.
  46   // The estimated file size is greater than or equal to actual file size after
  47   // all clients report their file usage,  and is monotonically increasing over
  48   // OpenFileHandle object life cycle, so that client may cache the value.
  49   int64 GetEstimatedFileSize() const;
  50
  51   int64 GetMaxWrittenOffset() const;
  52   const base::FilePath& platform_path() const;
  53
  54  private:
  55   friend class QuotaReservationBuffer;
  56
  57   OpenFileHandle(QuotaReservation* reservation,
  58                  OpenFileHandleContext* context);
  59
  60   scoped_refptr<QuotaReservation> reservation_;
  61   scoped_refptr<OpenFileHandleContext> context_;
  62
  63   base::SequenceChecker sequence_checker_;
  64
  65   DISALLOW_COPY_AND_ASSIGN(OpenFileHandle);
  66 };
  67
  68 }  // namespace storage
  69
  70 #endif  // STORAGE_BROWSER_FILEAPI_QUOTA_OPEN_FILE_HANDLE_H_