gdata: Move GDataWapiFeedLoader to a set of new files

chrome/browser/chromeos/gdata/gdata_wapi_feed_loader.h

+// Copyright (c) 2012 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_CHROMEOS_GDATA_GDATA_WAPI_FEED_LOADER_H_
+#define CHROME_BROWSER_CHROMEOS_GDATA_GDATA_WAPI_FEED_LOADER_H_
+
+#include "base/callback.h"
+#include "base/file_path.h"
+#include "base/observer_list.h"
+#include "chrome/browser/chromeos/gdata/gdata_errorcode.h"
+#include "chrome/browser/chromeos/gdata/gdata_files.h"
+
+namespace gdata {
+
+class DriveWebAppsRegistryInterface;
+class DocumentsServiceInterface;
+class GDataCache;
+struct GetDocumentsUiState;
+
+// Set of parameters sent to LoadDocumentFeedCallback callback.
+struct GetDocumentsParams {
+  GetDocumentsParams(int start_changestamp,
+                     int root_feed_changestamp,
+                     std::vector<DocumentFeed*>* feed_list,
+                     bool should_fetch_multiple_feeds,
+                     const FilePath& search_file_path,
+                     const std::string& search_query,
+                     const std::string& directory_resource_id,
+                     const FindEntryCallback& callback,
+                     GetDocumentsUiState* ui_state);
+  ~GetDocumentsParams();
+
+  // Changestamps are positive numbers in increasing order. The difference
+  // between two changestamps is proportional equal to number of items in
+  // delta feed between them - bigger the difference, more likely bigger
+  // number of items in delta feeds.
+  int start_changestamp;
+  int root_feed_changestamp;
+  scoped_ptr<std::vector<DocumentFeed*> > feed_list;
+  // Should we stop after getting first feed chunk, even if there is more
+  // data.
+  bool should_fetch_multiple_feeds;
+  FilePath search_file_path;
+  std::string search_query;
+  std::string directory_resource_id;
+  FindEntryCallback callback;
+  scoped_ptr<GetDocumentsUiState> ui_state;
+};
+
+// Callback run as a response to LoadFromServer.
+typedef base::Callback<void(GetDocumentsParams* params,
+                            GDataFileError error)>
+    LoadDocumentFeedCallback;
+
+// GDataWapiFeedLoader is used to load feeds from WAPI (codename for
+// Documents List API) and load the cached proto file.
+class GDataWapiFeedLoader {
+ public:
+  // Used to notify events from the loader.
+  // All events are notified on UI thread.
+  class Observer {
+   public:
+    // Triggered when a content of a directory has been changed.
+    // |directory_path| is a virtual directory path representing the
+    // changed directory.
+    virtual void OnDirectoryChanged(const FilePath& directory_path) {}
+
+    // Triggered when a document feed is fetched. |num_accumulated_entries|
+    // tells the number of entries fetched so far.
+    virtual void OnDocumentFeedFetched(int num_accumulated_entries) {}
+
+    // Triggered when the feed from the server is loaded.
+    virtual void OnFeedFromServerLoaded() {}
+
+   protected:
+    virtual ~Observer() {}
+  };
+
+  GDataWapiFeedLoader(
+      GDataDirectoryService* directory_service,
+      DocumentsServiceInterface* documents_service,
+      DriveWebAppsRegistryInterface* webapps_registry,
+      GDataCache* cache,
+      scoped_refptr<base::SequencedTaskRunner> blocking_task_runner_);
+  ~GDataWapiFeedLoader();
+
+  // Adds and removes the observer.
+  void AddObserver(Observer* observer);
+  void RemoveObserver(Observer* observer);
+
+  // Starts root feed load from the cache. If successful, it will try to find
+  // the file upon retrieval completion. In addition to that, it will
+  // initiate retrieval of the root feed from the server unless
+  // |should_load_from_server| is set to false. |should_load_from_server| is
+  // false only for testing.
+  void LoadFromCache(bool should_load_from_server,
+                     const FilePath& search_file_path,
+                     const FindEntryCallback& callback);
+
+  // Starts root feed load from the server. Value of |start_changestamp|
+  // determines the type of feed to load - 0 means root feed, every other
+  // value would trigger delta feed.
+  // In the case of loading the root feed we use |root_feed_changestamp| as its
+  // initial changestamp value since it does not come with that info.
+  // When done |load_feed_callback| is invoked.
+  // |entry_found_callback| is used only when this is invoked while searching
+  // for file info, and is used in |load_feed_callback|. If successful, it will
+  // try to find the file upon retrieval completion.
+  // |should_fetch_multiple_feeds| is true iff don't want to stop feed loading
+  // after we retrieve first feed chunk.
+  // If invoked as a part of content search, query will be set in
+  // |search_query|.
+  // If |feed_to_load| is set, this is feed url that will be used to load feed.
+  void LoadFromServer(
+      ContentOrigin initial_origin,
+      int start_changestamp,
+      int root_feed_changestamp,
+      bool should_fetch_multiple_feeds,
+      const FilePath& search_file_path,
+      const std::string& search_query,
+      const GURL& feed_to_load,
+      const std::string& directory_resource_id,
+      const FindEntryCallback& entry_found_callback,
+      const LoadDocumentFeedCallback& feed_load_callback);
+
+  // Retrieves account metadata and determines from the last change timestamp
+  // if the feed content loading from the server needs to be initiated.
+  void ReloadFromServerIfNeeded(
+      ContentOrigin initial_origin,
+      int local_changestamp,
+      const FilePath& search_file_path,
+      const FindEntryCallback& callback);
+
+  // Updates whole directory structure feeds collected in |feed_list|.
+  // On success, returns PLATFORM_FILE_OK. Record file statistics as UMA
+  // histograms.
+  //
+  // See comments at GDataWapiFeedProcessor::ApplyFeeds() for
+  // |start_changestamp| and |root_feed_changestamp|.
+  GDataFileError UpdateFromFeed(
+    const std::vector<DocumentFeed*>& feed_list,
+    int start_changestamp,
+    int root_feed_changestamp);
+
+ private:
+  // Callback for handling root directory refresh from the cache.
+  void OnProtoLoaded(LoadRootFeedParams* params);
+
+  // Continues handling root directory refresh after the directory service
+  // is fully loaded.
+  void ContinueWithInitializedDirectoryService(LoadRootFeedParams* params,
+                                               GDataFileError error);
+
+  // Helper callback for handling results of metadata retrieval initiated from
+  // ReloadFeedFromServerIfNeeded(). This method makes a decision about fetching
+  // the content of the root feed during the root directory refresh process.
+  void OnGetAccountMetadata(
+      ContentOrigin initial_origin,
+      int local_changestamp,
+      const FilePath& search_file_path,
+      const FindEntryCallback& callback,
+      GDataErrorCode status,
+      scoped_ptr<base::Value> feed_data);
+
+  // Callback for handling feed content fetching while searching for file info.
+  // This callback is invoked after async feed fetch operation that was
+  // invoked by StartDirectoryRefresh() completes. This callback will update
+  // the content of the refreshed directory object and continue initially
+  // started FindEntryByPath() request.
+  void OnFeedFromServerLoaded(GetDocumentsParams* params,
+                              GDataFileError error);
+
+  // Callback for handling response from |GDataDocumentsService::GetDocuments|.
+  // Invokes |callback| when done.
+  void OnGetDocuments(
+      ContentOrigin initial_origin,
+      const LoadDocumentFeedCallback& callback,
+      GetDocumentsParams* params,
+      base::TimeTicks start_time,
+      GDataErrorCode status,
+      scoped_ptr<base::Value> data);
+
+  // Save filesystem to disk.
+  void SaveFileSystem();
+
+  // Callback for handling UI updates caused by document fetching.
+  void OnNotifyDocumentFeedFetched(
+      base::WeakPtr<GetDocumentsUiState> ui_state);
+
+  GDataDirectoryService* directory_service_;  // Not owned.
+  DocumentsServiceInterface* documents_service_;  // Not owned.
+  DriveWebAppsRegistryInterface* webapps_registry_;  // Not owned.
+  GDataCache* cache_;  // Not owned.
+  scoped_refptr<base::SequencedTaskRunner> blocking_task_runner_;
+  ObserverList<Observer> observers_;
+
+  // Note: This should remain the last member so it'll be destroyed and
+  // invalidate its weak pointers before any other members are destroyed.
+  base::WeakPtrFactory<GDataWapiFeedLoader> weak_ptr_factory_;
+  DISALLOW_COPY_AND_ASSIGN(GDataWapiFeedLoader);
+};
+
+}  // namespace gdata
+
+#endif  // CHROME_BROWSER_CHROMEOS_GDATA_GDATA_WAPI_FEED_LOADER_H_