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      1 // Copyright 2014 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 STORAGE_BROWSER_FILEAPI_WATCHER_MANAGER_H_
      6 #define STORAGE_BROWSER_FILEAPI_WATCHER_MANAGER_H_
      7 
      8 #include <vector>
      9 
     10 #include "base/basictypes.h"
     11 #include "base/callback_forward.h"
     12 #include "base/files/file.h"
     13 
     14 namespace base {
     15 class Time;
     16 }
     17 
     18 namespace storage {
     19 
     20 class FileSystemOperationContext;
     21 class FileSystemURL;
     22 
     23 // An interface for providing entry observing capability for file system
     24 // backends.
     25 //
     26 // It is NOT valid to give null callback to this class, and implementors
     27 // can assume that they don't get any null callbacks.
     28 class WatcherManager {
     29  public:
     30   typedef base::Callback<void(base::File::Error result)> StatusCallback;
     31 
     32   // Observes watched entries.
     33   class Observer {
     34    public:
     35     Observer() {}
     36     virtual ~Observer() {}
     37 
     38     // Notifies about an entry represented by |url| being changed.
     39     virtual void OnEntryChanged(const FileSystemURL& url) = 0;
     40 
     41     // Notifies about an entry represented by |url| being removed.
     42     virtual void OnEntryRemoved(const FileSystemURL& url) = 0;
     43   };
     44 
     45   virtual ~WatcherManager() {}
     46 
     47   virtual void AddObserver(Observer* observer) = 0;
     48   virtual void RemoveObserver(Observer* observer) = 0;
     49   virtual bool HasObserver(Observer* observer) const = 0;
     50 
     51   // Observes a directory entry. If the |recursive| mode is not supported then
     52   // FILE_ERROR_INVALID_OPERATION must be returned as an error. If the |url| is
     53   // already watched, or setting up the watcher fails, then |callback|
     54   // must be called with a specific error code. Otherwise |callback| must be
     55   // called with the FILE_OK error code.
     56   virtual void WatchDirectory(const FileSystemURL& url,
     57                               bool recursive,
     58                               const StatusCallback& callback) = 0;
     59 
     60   // Stops observing an entry represented by |url|.
     61   virtual void UnwatchEntry(const FileSystemURL& url,
     62                             const StatusCallback& callback) = 0;
     63 };
     64 
     65 }  // namespace storage
     66 
     67 #endif  // STORAGE_BROWSER_FILEAPI_WATCHER_MANAGER_H_
     68