Media Galleries API Picasa: Make PicasaDataProvider handle async PMP and INI parsing robustly.

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_forward.h"
+#include "base/callback.h"
 #include "base/files/file_path.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
+  // 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(const base::Closure& ready_callback);
+  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();
-  // TODO(tommycli): Implement album contents. GetAlbumContents(...)
-
- protected:
-  // Protected for test class usage.
-  void OnDataRefreshed(const base::Closure& ready_callback,
-                       bool parse_success, const std::vector<AlbumInfo>& albums,
-                       const std::vector<AlbumInfo>& folder);
+  scoped_ptr<AlbumImagesMap> GetAlbumsImages();
 
  private:
+  enum State {
+    STALE_DATA_STATE,
+    INVALID_DATA_STATE,
+    ALBUM_LIST_FRESH_STATE,

[vandebo (ex-Chrome), 2013/07/12 22:17:28]

ALBUM_LIST_FRESH_STATE and LIST_OF_ALBUMS_AND_FOLDERS_DATA should have a common
root.

[tommycli, 2013/08/14 18:23:17]

Done.

+    ALBUMS_IMAGES_FRESH_STATE
+  };
+
   friend class PicasaFileUtilTest;
 
+  // Notifies data provider that any currently cached data is stale.
+  void InvalidateData();
+
+  // Should only be called if there's actually ready_callbacks waiting on data.

[vandebo (ex-Chrome), 2013/07/12 22:17:28]

Method comment should describe what the method does.  This might be better as a
DCHECK at the top of the method.

[tommycli, 2013/08/14 18:23:17]

Done.

+  void DoRefreshIfNecessary();
+
+  void OnAlbumListRefreshed(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);
 
   AlbumMap album_map_;
   AlbumMap folder_map_;
+  AlbumImagesMap albums_images_;
 
   base::FilePath database_path_;
-  bool needs_refresh_;
 
+  State state_;
+
+  // Callbacks that are waiting for their requested data to be ready.
+  std::queue<ReadyCallback> album_list_ready_callbacks_;
+  std::queue<ReadyCallback> albums_indexer_ready_callbacks_;
+
+  // Stores the "live" in-flight utility processes. Callbacks from other
+  // (older) utility processes are stale and ignored. Only one of these should

[vandebo (ex-Chrome), 2013/07/12 22:17:28]

nit: Only one of these at a time should be non-NULL.

[tommycli, 2013/08/14 18:23:17]

Done.

+  // ever be non-NULL.
   scoped_refptr<SafePicasaAlbumTableReader> album_table_reader_;
+  scoped_refptr<SafePicasaAlbumsIndexer> albums_indexer_;
 
   base::WeakPtrFactory<PicasaDataProvider> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(PicasaDataProvider);
 };
 
 }  // namespace picasa
 
 #endif  // CHROME_BROWSER_MEDIA_GALLERIES_FILEAPI_PICASA_PICASA_DATA_PROVIDER_H_