chrome/browser/chromeos/file_manager/file_watcher.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_CHROMEOS_FILE_MANAGER_FILE_WATCHER_H_
   6 #define CHROME_BROWSER_CHROMEOS_FILE_MANAGER_FILE_WATCHER_H_
   7
   8 #include <map>
   9 #include <string>
  10
  11 #include "base/callback_forward.h"
  12 #include "base/files/file_path.h"
  13 #include "base/files/file_path_watcher.h"
  14 #include "base/memory/weak_ptr.h"
  15
  16 namespace file_manager {
  17
  18 // This class is used to watch changes in the given virtual path, remember
  19 // what extensions are watching the path.
  20 //
  21 // For local files, the class maintains a FilePathWatcher instance and
  22 // remembers what extensions are watching the path.
  23 //
  24 // For remote files (ex. files on Drive), the class just remembers what
  25 // extensions are watching the path. The actual file watching for remote
  26 // files is handled differently in EventRouter.
  27 class FileWatcher {
  28  public:
  29   typedef base::Callback<void(bool success)> BoolCallback;
  30
  31   // Creates a FileWatcher associated with the virtual path.
  32   explicit FileWatcher(const base::FilePath& virtual_path);
  33
  34   ~FileWatcher();
  35
  36   // Remembers that the extension of |extension_id| is watching the virtual
  37   // path.
  38   //
  39   // If this function is called more than once with the same extension ID,
  40   // the class increments the counter internally, and RemoveExtension()
  41   // decrements the counter, and forgets the extension when the counter
  42   // becomes zero.
  43   void AddExtension(const std::string& extension_id);
  44
  45   // Forgets that the extension of |extension_id| is watching the virtual path,
  46   // or just decrements the internal counter for the extension ID. See the
  47   // comment at AddExtension() for details.
  48   void RemoveExtension(const std::string& extension_id);
  49
  50   // Returns IDs of the extensions watching virtual_path. The returned list
  51   // is sorted in the alphabetical order and contains no duplicates.
  52   std::vector<std::string> GetExtensionIds() const;
  53
  54   // Returns the virtual path associated with the FileWatcher.
  55   const base::FilePath& virtual_path() const { return virtual_path_; }
  56
  57   // Starts watching a local file at |local_path|. |file_watcher_callback|
  58   // will be called when changes are notified.
  59   //
  60   // |callback| will be called with true, if the file watch is started
  61   // successfully, or false if failed. |callback| must not be null.
  62   void WatchLocalFile(
  63       const base::FilePath& local_path,
  64       const base::FilePathWatcher::Callback& file_watcher_callback,
  65       const BoolCallback& callback);
  66
  67  private:
  68   // Called when a FilePathWatcher is created and started.
  69   // |file_path_watcher| is NULL, if the watcher wasn't started successfully.
  70   void OnWatcherStarted(const BoolCallback& callback,
  71                         base::FilePathWatcher* file_path_watcher);
  72
  73   base::FilePathWatcher* local_file_watcher_;
  74   base::FilePath virtual_path_;
  75   // Map of extension-id to counter. See the comment at AddExtension() for
  76   // why we need to count.
  77   typedef std::map<std::string, int> ExtensionCountMap;
  78   ExtensionCountMap extensions_;
  79
  80   // Note: This should remain the last member so it'll be destroyed and
  81   // invalidate the weak pointers before any other members are destroyed.
  82   base::WeakPtrFactory<FileWatcher> weak_ptr_factory_;
  83 };
  84
  85 }  // namespace file_manager
  86
  87 #endif  // CHROME_BROWSER_CHROMEOS_FILE_MANAGER_FILE_WATCHER_H_