chrome/browser/sync_file_system/local/local_file_change_tracker.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_CHANGE_TRACKER_H_
   6 #define CHROME_BROWSER_SYNC_FILE_SYSTEM_LOCAL_LOCAL_FILE_CHANGE_TRACKER_H_
   7
   8 #include <deque>
   9 #include <map>
  10 #include <string>
  11
  12 #include "base/basictypes.h"
  13 #include "base/compiler_specific.h"
  14 #include "base/files/file_path.h"
  15 #include "base/memory/ref_counted.h"
  16 #include "base/memory/scoped_ptr.h"
  17 #include "base/synchronization/lock.h"
  18 #include "chrome/browser/sync_file_system/file_change.h"
  19 #include "chrome/browser/sync_file_system/sync_status_code.h"
  20 #include "webkit/browser/fileapi/file_observers.h"
  21 #include "webkit/browser/fileapi/file_system_url.h"
  22
  23 namespace base {
  24 class SequencedTaskRunner;
  25 }
  26
  27 namespace fileapi {
  28 class FileSystemContext;
  29 class FileSystemURL;
  30 }
  31
  32 namespace sync_file_system {
  33
  34 // Tracks local file changes for cloud-backed file systems.
  35 // All methods must be called on the file_task_runner given to the constructor.
  36 // Owned by FileSystemContext.
  37 class LocalFileChangeTracker
  38     : public fileapi::FileUpdateObserver,
  39       public fileapi::FileChangeObserver {
  40  public:
  41   // |file_task_runner| must be the one where the observee file operations run.
  42   // (So that we can make sure DB operations are done before actual update
  43   // happens)
  44   LocalFileChangeTracker(const base::FilePath& base_path,
  45                          base::SequencedTaskRunner* file_task_runner);
  46   virtual ~LocalFileChangeTracker();
  47
  48   // FileUpdateObserver overrides.
  49   virtual void OnStartUpdate(const fileapi::FileSystemURL& url) OVERRIDE;
  50   virtual void OnUpdate(
  51       const fileapi::FileSystemURL& url, int64 delta) OVERRIDE {}
  52   virtual void OnEndUpdate(const fileapi::FileSystemURL& url) OVERRIDE;
  53
  54   // FileChangeObserver overrides.
  55   virtual void OnCreateFile(const fileapi::FileSystemURL& url) OVERRIDE;
  56   virtual void OnCreateFileFrom(const fileapi::FileSystemURL& url,
  57                                 const fileapi::FileSystemURL& src) OVERRIDE;
  58   virtual void OnRemoveFile(const fileapi::FileSystemURL& url) OVERRIDE;
  59   virtual void OnModifyFile(const fileapi::FileSystemURL& url) OVERRIDE;
  60   virtual void OnCreateDirectory(const fileapi::FileSystemURL& url) OVERRIDE;
  61   virtual void OnRemoveDirectory(const fileapi::FileSystemURL& url) OVERRIDE;
  62
  63   // Retrieves an array of |url| which have more than one pending changes.
  64   // If |max_urls| is non-zero (recommended in production code) this
  65   // returns URLs up to the number from the ones that have smallest
  66   // change_seq numbers (i.e. older changes).
  67   void GetNextChangedURLs(std::deque<fileapi::FileSystemURL>* urls,
  68                           int max_urls);
  69
  70   // Returns all changes recorded for the given |url|.
  71   // Note that this also returns demoted changes.
  72   // This should be called after writing is disabled.
  73   void GetChangesForURL(const fileapi::FileSystemURL& url,
  74                         FileChangeList* changes);
  75
  76   // Clears the pending changes recorded in this tracker for |url|.
  77   void ClearChangesForURL(const fileapi::FileSystemURL& url);
  78
  79   // Creates a fresh (empty) in-memory record for |url|.
  80   // Note that new changes are recorded to the mirror too.
  81   void CreateFreshMirrorForURL(const fileapi::FileSystemURL& url);
  82
  83   // Removes a mirror for |url|, and commits the change status to database.
  84   void RemoveMirrorAndCommitChangesForURL(const fileapi::FileSystemURL& url);
  85
  86   // Resets the changes to the ones recorded in mirror for |url|, and
  87   // commits the updated change status to database.
  88   void ResetToMirrorAndCommitChangesForURL(const fileapi::FileSystemURL& url);
  89
  90   // Re-inserts changes into the separate demoted_changes_ queue. They won't
  91   // be fetched by GetNextChangedURLs() unless PromoteDemotedChanges() is
  92   // called.
  93   void DemoteChangesForURL(const fileapi::FileSystemURL& url);
  94
  95   // Promotes all demoted changes to the normal queue. Returns true if it has
  96   // promoted any changes.
  97   bool PromoteDemotedChanges();
  98
  99   // Called by FileSyncService at the startup time to restore last dirty changes
 100   // left after the last shutdown (if any).
 101   SyncStatusCode Initialize(fileapi::FileSystemContext* file_system_context);
 102
 103   // Resets all the changes recorded for the given |origin| and |type|.
 104   // TODO(kinuko,nhiroki): Ideally this should be automatically called in
 105   // DeleteFileSystem via QuotaUtil::DeleteOriginDataOnFileThread.
 106   void ResetForFileSystem(const GURL& origin, fileapi::FileSystemType type);
 107
 108   // This method is (exceptionally) thread-safe.
 109   int64 num_changes() const {
 110     base::AutoLock lock(num_changes_lock_);
 111     return num_changes_;
 112   }
 113
 114  private:
 115   class TrackerDB;
 116   friend class CannedSyncableFileSystem;
 117   friend class LocalFileChangeTrackerTest;
 118   friend class LocalFileSyncContext;
 119   friend class LocalFileSyncContextTest;
 120   friend class SyncableFileSystemTest;
 121
 122   struct ChangeInfo {
 123     ChangeInfo();
 124     ~ChangeInfo();
 125     FileChangeList change_list;
 126     int64 change_seq;
 127   };
 128
 129   typedef std::map<fileapi::FileSystemURL, ChangeInfo,
 130       fileapi::FileSystemURL::Comparator>
 131           FileChangeMap;
 132   typedef std::map<int64, fileapi::FileSystemURL> ChangeSeqMap;
 133
 134   void UpdateNumChanges();
 135
 136   // This does mostly same as calling GetNextChangedURLs with max_url=0
 137   // except that it returns urls in set rather than in deque.
 138   // Used only in testings.
 139   void GetAllChangedURLs(fileapi::FileSystemURLSet* urls);
 140
 141   // Used only in testings.
 142   void DropAllChanges();
 143
 144   // Database related methods.
 145   SyncStatusCode MarkDirtyOnDatabase(const fileapi::FileSystemURL& url);
 146   SyncStatusCode ClearDirtyOnDatabase(const fileapi::FileSystemURL& url);
 147
 148   SyncStatusCode CollectLastDirtyChanges(
 149       fileapi::FileSystemContext* file_system_context);
 150   void RecordChange(const fileapi::FileSystemURL& url,
 151                     const FileChange& change);
 152
 153   static void RecordChangeToChangeMaps(const fileapi::FileSystemURL& url,
 154                                        const FileChange& change,
 155                                        int change_seq,
 156                                        FileChangeMap* changes,
 157                                        ChangeSeqMap* change_seqs);
 158
 159   bool initialized_;
 160
 161   scoped_refptr<base::SequencedTaskRunner> file_task_runner_;
 162
 163   FileChangeMap changes_;
 164   ChangeSeqMap change_seqs_;
 165
 166   FileChangeMap mirror_changes_;  // For mirrors.
 167   FileChangeMap demoted_changes_;  // For demoted changes.
 168
 169   scoped_ptr<TrackerDB> tracker_db_;
 170
 171   // Change sequence number. Briefly gives a hint about the order of changes,
 172   // but they are updated when a new change comes on the same file (as
 173   // well as Drive's changestamps).
 174   int64 current_change_seq_;
 175
 176   // This can be accessed on any threads (with num_changes_lock_).
 177   int64 num_changes_;
 178   mutable base::Lock num_changes_lock_;
 179
 180   DISALLOW_COPY_AND_ASSIGN(LocalFileChangeTracker);
 181 };
 182
 183 }  // namespace sync_file_system
 184
 185 #endif  // CHROME_BROWSER_SYNC_FILE_SYSTEM_LOCAL_LOCAL_FILE_CHANGE_TRACKER_H_