chrome/browser/sync_file_system/local/local_file_sync_status.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 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
  18 namespace storage {
  19 class FileSystemURL;
  20 }
  21
  22 namespace 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.
  33 class 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   base::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_