DomStorage commit task sequencing.

webkit/dom_storage/dom_storage_area.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 WEBKIT_DOM_STORAGE_DOM_STORAGE_AREA_H_
 #define WEBKIT_DOM_STORAGE_DOM_STORAGE_AREA_H_
 #pragma once
 
 #include "base/file_path.h"
 #include "base/gtest_prod_util.h"
@@ skipping 30 matching lines @@
   unsigned Length();
   NullableString16 Key(unsigned index);
   NullableString16 GetItem(const string16& key);
   bool SetItem(const string16& key, const string16& value,
                NullableString16* old_value);
   bool RemoveItem(const string16& key, string16* old_value);
   bool Clear();
 
   DomStorageArea* ShallowCopy(int64 destination_namespace_id);
 
+  // Schedules the commit of any unsaved changes and enters a
+  // shutdown state such that the value getters and setters will
+  // no longer do anything.
+  void Shutdown();
+
  private:
+  friend class DomStorageAreaTest;
   FRIEND_TEST_ALL_PREFIXES(DomStorageAreaTest, DomStorageAreaBasics);
   FRIEND_TEST_ALL_PREFIXES(DomStorageAreaTest, BackingDatabaseOpened);
   FRIEND_TEST_ALL_PREFIXES(DomStorageAreaTest, TestDatabaseFilePath);
+  FRIEND_TEST_ALL_PREFIXES(DomStorageAreaTest, CommitTasks);
+  FRIEND_TEST_ALL_PREFIXES(DomStorageAreaTest, CommitChangesAtShutdown);
   friend class base::RefCountedThreadSafe<DomStorageArea>;
 
+  struct CommitBatch {
+    bool clear_all_first;
+    ValuesMap changed_values;
+    CommitBatch();
+    ~CommitBatch();
+  };
+
+  ~DomStorageArea();
+
   // If we haven't done so already and this is a local storage area,
   // will attempt to read any values for this origin currently
   // stored on disk.
   void InitialImportIfNeeded();
 
-  // Posts a task to write the set of changed values to disk.
-  void ScheduleCommitChanges();
+  // Post tasks to defer writing a batch of changed values to
+  // disk on the commit sequence, and to call back on the main
+  // task sequence when complete.
+  CommitBatch* CreateCommitBatchIfNeeded();
+  void OnCommitTimer();
   void CommitChanges();
+  void OnCommitComplete();
 
-  ~DomStorageArea();
+  void ShutdownInCommitSequence();
 
   int64 namespace_id_;
   GURL origin_;
   FilePath directory_;
   scoped_refptr<DomStorageTaskRunner> task_runner_;
   scoped_refptr<DomStorageMap> map_;
   scoped_ptr<DomStorageDatabase> backing_;
-  bool initial_import_done_;
-  ValuesMap changed_values_;
-  bool clear_all_next_commit_;
-  bool commit_in_flight_;
+  bool is_initial_import_done_;
+  bool is_shutdown_;
+  scoped_ptr<CommitBatch> commit_batch_;
+  scoped_ptr<CommitBatch> in_flight_commit_batch_;
 };
 
 }  // namespace dom_storage
 
 #endif  // WEBKIT_DOM_STORAGE_DOM_STORAGE_AREA_H_