Add OnSyncEnabled/OnWriteEnabled notification handling to operation runner

webkit/fileapi/syncable/local_file_sync_status.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef WEBKIT_FILEAPI_SYNCABLE_LOCAL_FILE_SYNC_STATUS_H_
 #define WEBKIT_FILEAPI_SYNCABLE_LOCAL_FILE_SYNC_STATUS_H_
 
 #include <map>
 #include <set>
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
+#include "base/observer_list.h"
 #include "base/threading/non_thread_safe.h"
 #include "webkit/fileapi/file_system_url.h"
 
 namespace fileapi {
 
 // Represents local file sync status.
 // This class is supposed to run only on IO thread.
 //
 // This class manages two important synchronization flags: writing (counter)
 // and syncing (flag).  Writing counter keeps track of which URL is in
 // writing and syncing flag indicates which URL is in syncing.
 //
 // An invariant of this class is: no FileSystem objects should be both
 // in syncing_ and writing_ status, i.e. trying to increment writing
 // while the target url is in syncing must fail and vice versa.
 class WEBKIT_STORAGE_EXPORT LocalFileSyncStatus : public base::NonThreadSafe {
  public:
+  class WEBKIT_STORAGE_EXPORT Observer {
+   public:
+    Observer() {}
+    virtual void OnSyncEnabled(const FileSystemURL& url) = 0;
+    virtual void OnWriteEnabled(const FileSystemURL& url) = 0;
+   private:
+    DISALLOW_COPY_AND_ASSIGN(Observer);
+  };
+
   LocalFileSyncStatus();
   ~LocalFileSyncStatus();
 
   // Increment writing counter for |url|.
   // This should not be called if the |url| is not writable.
   void StartWriting(const FileSystemURL& url);
 
   // Decrement writing counter for |url|.
   void EndWriting(const FileSystemURL& url);
 
   // Start syncing for |url| and disable writing.
   // This should not be called if |url| is in writing.
   void StartSyncing(const FileSystemURL& url);
 
   // Clears the syncing flag for |url| and enable writing.
   void EndSyncing(const FileSystemURL& url);
 
   // Returns true if the |url| or its parent or child is in writing.
   bool IsWriting(const FileSystemURL& url) const;
 
   // Returns true if the |url| is enabled for writing (i.e. not in syncing).
   bool IsWritable(const FileSystemURL& url) const;
 
+  void AddObserver(Observer* observer);
+  void RemoveObserver(Observer* observer);
+
  private:
   typedef std::map<FileSystemURL, int64, FileSystemURL::Comparator> URLCountMap;
   typedef std::set<FileSystemURL, FileSystemURL::Comparator> URLSet;
 
   bool IsChildOrParentWriting(const FileSystemURL& url) const;
   bool IsChildOrParentSyncing(const FileSystemURL& url) const;
 
   // If this count is non-zero positive there're ongoing write operations.
   URLCountMap writing_;
 
   // If this flag is set sync process is running on the file.
   URLSet syncing_;
 
+  ObserverList<Observer> observer_list_;
+
   DISALLOW_COPY_AND_ASSIGN(LocalFileSyncStatus);
 };
 
 }  // namespace fileapi
 
 #endif  // WEBKIT_FILEAPI_SYNCABLE_LOCAL_FILE_SYNC_STATUS_H_