local_file_sync_status.h revision 5c02ac1a9c1b504631c0a3d2b6e737b5d738bae1 
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 CHROME_BROWSER_SYNC_FILE_SYSTEM_LOCAL_LOCAL_FILE_SYNC_STATUS_H_
6#define CHROME_BROWSER_SYNC_FILE_SYSTEM_LOCAL_LOCAL_FILE_SYNC_STATUS_H_
7
8#include <map>
9#include <set>
10
11#include "base/basictypes.h"
12#include "base/compiler_specific.h"
13#include "base/gtest_prod_util.h"
14#include "base/observer_list.h"
15#include "base/threading/non_thread_safe.h"
16#include "webkit/browser/fileapi/file_system_url.h"
17
18namespace fileapi {
19class FileSystemURL;
20}
21
22namespace sync_file_system {
23
24// Represents local file sync status.
25// This class is supposed to run only on IO thread.
26//
27// This class manages two important synchronization flags: writing (counter)
28// and syncing (flag).  Writing counter keeps track of which URL is in
29// writing and syncing flag indicates which URL is in syncing.
30//
31// An entry can have multiple writers but sync is exclusive and cannot overwrap
32// with any writes or syncs.
33class LocalFileSyncStatus
34    : public base::NonThreadSafe {
35 public:
36  typedef std::pair<GURL, fileapi::FileSystemType> OriginAndType;
37
38  class Observer {
39   public:
40    Observer() {}
41    virtual ~Observer() {}
42    virtual void OnSyncEnabled(const fileapi::FileSystemURL& url) = 0;
43    virtual void OnWriteEnabled(const fileapi::FileSystemURL& url) = 0;
44   private:
45    DISALLOW_COPY_AND_ASSIGN(Observer);
46  };
47
48  LocalFileSyncStatus();
49  ~LocalFileSyncStatus();
50
51  // Increment writing counter for |url|.
52  // This should not be called if the |url| is not writable.
53  void StartWriting(const fileapi::FileSystemURL& url);
54
55  // Decrement writing counter for |url|.
56  void EndWriting(const fileapi::FileSystemURL& url);
57
58  // Start syncing for |url| and disable writing.
59  // This should not be called if |url| is in syncing or in writing.
60  void StartSyncing(const fileapi::FileSystemURL& url);
61
62  // Clears the syncing flag for |url| and enable writing.
63  void EndSyncing(const fileapi::FileSystemURL& url);
64
65  // Returns true if the |url| or its parent or child is in writing.
66  bool IsWriting(const fileapi::FileSystemURL& url) const;
67
68  // Returns true if the |url| is enabled for writing (i.e. not in syncing).
69  bool IsWritable(const fileapi::FileSystemURL& url) const;
70
71  // Returns true if the |url| is enabled for syncing (i.e. neither in
72  // syncing nor writing).
73  bool IsSyncable(const fileapi::FileSystemURL& url) const;
74
75  void AddObserver(Observer* observer);
76  void RemoveObserver(Observer* observer);
77
78 private:
79  FRIEND_TEST_ALL_PREFIXES(LocalFileSyncStatusTest, WritingOnPathsWithPeriod);
80  FRIEND_TEST_ALL_PREFIXES(LocalFileSyncStatusTest, SyncingOnPathsWithPeriod);
81
82  typedef std::set<base::FilePath> PathSet;
83  typedef std::map<OriginAndType, PathSet> URLSet;
84
85  typedef std::map<base::FilePath, int64> PathBucket;
86  typedef std::map<OriginAndType, PathBucket> URLBucket;
87
88  bool IsChildOrParentWriting(const fileapi::FileSystemURL& url) const;
89  bool IsChildOrParentSyncing(const fileapi::FileSystemURL& url) const;
90
91  // If this count is non-zero positive there're ongoing write operations.
92  URLBucket writing_;
93
94  // If this flag is set sync process is running on the file.
95  URLSet syncing_;
96
97  ObserverList<Observer> observer_list_;
98
99  DISALLOW_COPY_AND_ASSIGN(LocalFileSyncStatus);
100};
101
102}  // namespace sync_file_system
103
104#endif  // CHROME_BROWSER_SYNC_FILE_SYSTEM_LOCAL_LOCAL_FILE_SYNC_STATUS_H_
105