Media Galleries API Picasa: Add file watch to invalidate database data on disk write.

chrome/browser/media_galleries/fileapi/picasa/picasa_data_provider.h

 // Copyright 2013 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 CHROME_BROWSER_MEDIA_GALLERIES_FILEAPI_PICASA_PICASA_DATA_PROVIDER_H_
 #define CHROME_BROWSER_MEDIA_GALLERIES_FILEAPI_PICASA_PICASA_DATA_PROVIDER_H_
 
 #include <map>
 #include <queue>
 #include <string>
 #include <vector>
 
-#include "base/callback.h"
+#include "base/basictypes.h"
+#include "base/callback_forward.h"
 #include "base/files/file_path.h"
+#include "base/files/file_path_watcher.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/time/time.h"
 #include "chrome/common/media_galleries/picasa_types.h"
 
 namespace picasa {
 
 class SafePicasaAlbumTableReader;
 class SafePicasaAlbumsIndexer;
 
 // Created and owned by ImportedMediaGalleryRegistryTaskRunnerValues
 class PicasaDataProvider {
  public:
   typedef base::Callback<void(bool)> ReadyCallback;
 
   enum DataType {
     LIST_OF_ALBUMS_AND_FOLDERS_DATA,
     ALBUMS_IMAGES_DATA
   };
 
   explicit PicasaDataProvider(const base::FilePath& database_path);
   virtual ~PicasaDataProvider();
 
   // Ask the data provider to refresh the data if necessary. |ready_callback|
   // will be called when the data is up to date.
-  // TODO(tommycli): Investigate having the callback return a bool indicating
-  // success or failure - and handling it intelligently in PicasaFileUtil.
   void RefreshData(DataType needed_data, const ReadyCallback& ready_callback);
 
   // These methods return scoped_ptrs because we want to return a copy that
   // will not change to the caller.
   scoped_ptr<AlbumMap> GetAlbums();
   scoped_ptr<AlbumMap> GetFolders();
   // |error| must be non-NULL.
   scoped_ptr<AlbumImages> FindAlbumImages(const std::string& key,
                                           base::PlatformFileError* error);
 
+ protected:
+  // Notifies data provider that any currently cached data is stale.
+  virtual void InvalidateData();
+
  private:
   enum State {
     STALE_DATA_STATE,
     INVALID_DATA_STATE,
     LIST_OF_ALBUMS_AND_FOLDERS_FRESH_STATE,
     ALBUMS_IMAGES_FRESH_STATE
   };
 
   friend class PicasaFileUtilTest;
-  friend class PicasaDataProviderInvalidateSimpleTest;
-  friend class PicasaDataProviderInvalidateInflightTableReaderTest;
-  friend class PicasaDataProviderInvalidateInflightAlbumsIndexerTest;
+  friend class TestPicasaDataProvider;
 
-  // Notifies data provider that any currently cached data is stale.
-  void InvalidateData();
+  // Called when the FilePathWatcher for Picasa's temp directory has started.
+  void OnTempDirWatchStarted(
+      scoped_ptr<base::FilePathWatcher> temp_dir_watcher);
+
+  // Called when Picasa's temp directory has changed. Virtual for testing.
+  virtual void OnTempDirChanged(const base::FilePath& temp_dir_path,
+                                bool error);
 
   // Kicks off utility processes needed to fulfill any pending callbacks.
   void DoRefreshIfNecessary();
 
   void OnAlbumTableReaderDone(scoped_refptr<SafePicasaAlbumTableReader> reader,
                               bool parse_success,
                               const std::vector<AlbumInfo>& albums,
                               const std::vector<AlbumInfo>& folder);
 
   void OnAlbumsIndexerDone(scoped_refptr<SafePicasaAlbumsIndexer> indexer,
                            bool success,
                            const picasa::AlbumImagesMap& albums_images);
 
   static std::string DateToPathString(const base::Time& time);
   static void UniquifyNames(const std::vector<AlbumInfo>& info_list,
                             AlbumMap* result_map);
 
-  // Methods are used in the browser test to tweak internal data for testing.
-  void SetDatabasePathForTesting(const base::FilePath& database_path);
-  void SetAlbumMapsForTesting(const AlbumMap& album_map,
-                              const AlbumMap& folder_map);
-
   AlbumMap album_map_;
   AlbumMap folder_map_;
   AlbumImagesMap albums_images_;
 
   base::FilePath database_path_;
 
   State state_;
 
   // Callbacks that are waiting for their requested data to be ready.
   std::queue<ReadyCallback> album_list_ready_callbacks_;
   std::queue<ReadyCallback> albums_index_ready_callbacks_;
 
   // Stores the "live" in-flight utility processes. Callbacks from other
   // (older) utility processes are stale and ignored. Only one of these at a
   // time should be non-NULL.
   scoped_refptr<SafePicasaAlbumTableReader> album_table_reader_;
   scoped_refptr<SafePicasaAlbumsIndexer> albums_indexer_;
 
+  // We watch the temp dir, as we can't detect database file modifications on
+  // Mac, but we are able to detect creation and deletion of temporary files.
+  scoped_ptr<base::FilePathWatcher> temp_dir_watcher_;
+
   base::WeakPtrFactory<PicasaDataProvider> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(PicasaDataProvider);
 };
 
 }  // namespace picasa
 
 #endif  // CHROME_BROWSER_MEDIA_GALLERIES_FILEAPI_PICASA_PICASA_DATA_PROVIDER_H_