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 "storage/browser/fileapi/file_system_url.h"
17
18namespace storage {
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, storage::FileSystemType> OriginAndType;
37
38  class Observer {
39   public:
40    Observer() {}
41    virtual ~Observer() {}
42    virtual void OnSyncEnabled(const storage::FileSystemURL& url) = 0;
43    virtual void OnWriteEnabled(const storage::FileSystemURL& url) = 0;
44
45   private:
46    DISALLOW_COPY_AND_ASSIGN(Observer);
47  };
48
49  LocalFileSyncStatus();
50  ~LocalFileSyncStatus();
51
52  // Increment writing counter for |url|.
53  // This should not be called if the |url| is not writable.
54  void StartWriting(const storage::FileSystemURL& url);
55
56  // Decrement writing counter for |url|.
57  void EndWriting(const storage::FileSystemURL& url);
58
59  // Start syncing for |url| and disable writing.
60  // This should not be called if |url| is in syncing or in writing.
61  void StartSyncing(const storage::FileSystemURL& url);
62
63  // Clears the syncing flag for |url| and enable writing.
64  void EndSyncing(const storage::FileSystemURL& url);
65
66  // Returns true if the |url| or its parent or child is in writing.
67  bool IsWriting(const storage::FileSystemURL& url) const;
68
69  // Returns true if the |url| is enabled for writing (i.e. not in syncing).
70  bool IsWritable(const storage::FileSystemURL& url) const;
71
72  // Returns true if the |url| is enabled for syncing (i.e. neither in
73  // syncing nor writing).
74  bool IsSyncable(const storage::FileSystemURL& url) const;
75
76  void AddObserver(Observer* observer);
77  void RemoveObserver(Observer* observer);
78
79 private:
80  FRIEND_TEST_ALL_PREFIXES(LocalFileSyncStatusTest, WritingOnPathsWithPeriod);
81  FRIEND_TEST_ALL_PREFIXES(LocalFileSyncStatusTest, SyncingOnPathsWithPeriod);
82
83  typedef std::set<base::FilePath> PathSet;
84  typedef std::map<OriginAndType, PathSet> URLSet;
85
86  typedef std::map<base::FilePath, int64> PathBucket;
87  typedef std::map<OriginAndType, PathBucket> URLBucket;
88
89  bool IsChildOrParentWriting(const storage::FileSystemURL& url) const;
90  bool IsChildOrParentSyncing(const storage::FileSystemURL& url) const;
91
92  // If this count is non-zero positive there're ongoing write operations.
93  URLBucket writing_;
94
95  // If this flag is set sync process is running on the file.
96  URLSet syncing_;
97
98  ObserverList<Observer> observer_list_;
99
100  DISALLOW_COPY_AND_ASSIGN(LocalFileSyncStatus);
101};
102
103}  // namespace sync_file_system
104
105#endif  // CHROME_BROWSER_SYNC_FILE_SYSTEM_LOCAL_LOCAL_FILE_SYNC_STATUS_H_
106