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:
+  enum DataType {
+    ALBUM_LIST_DATA,

[vandebo (ex-Chrome), 2013/07/11 23:22:37]

Based on these name and my end of day fog, I don't know which one is which.  We
can probably do better on names here.

[tommycli, 2013/07/12 01:37:48]

Done.

+    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. |refresh_album_contents|
+  // is true if the caller wants the album contents also.
   // 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 base::Closure& 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,
+    ALBUM_LIST_FRESH_STATE,
+    ALBUMS_IMAGES_FRESH_STATE
+  };
+
   friend class PicasaFileUtilTest;
 
+  // Notifies data provider that any currently cached data is stale.
+  void InvalidateData();
+
+  void EnsureAlbumListRefreshed(const base::Closure& ready_callback);
+  void EnsureAlbumsImagesRefreshed(const base::Closure& ready_callback);
+
+  void StartAlbumListRefreshIfNecessary();
+  void StartAlbumsImagesRefreshIfNecessary();
+
+  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,
+                           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 data_state_;
+
+  // Callbacks that are waiting for their requested data to be ready.
+  std::queue<base::Closure> album_list_ready_callbacks_;
+  std::queue<base::Closure> 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
+  // 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_