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"
 #include "base/memory/ref_counted.h"
 #include "base/nullable_string16.h"
 #include "base/string16.h"
 #include "googleurl/src/gurl.h"
 #include "webkit/dom_storage/dom_storage_database.h"
 #include "webkit/dom_storage/dom_storage_types.h"
 
 namespace dom_storage {
 
 class DomStorageMap;
 class DomStorageTaskRunner;
 
 // Container for a per-origin Map of key/value pairs potentially
 // backed by storage on disk and lazily commits changes to disk.
 // See class comments for DomStorageContext for a larger overview.
 class DomStorageArea
     : public base::RefCountedThreadSafe<DomStorageArea> {
 
  public:
+  static FilePath DatabaseFileNameFromOrigin(const GURL& origin);

[benm (inactive), 2012/03/19 14:22:53]

Why is this public now?

[michaeln, 2012/03/19 16:04:42]

This change really belongs in https://chromiumcodereview.appspot.com/9695013/

+  static const FilePath::CharType kDatabaseFileExtension[];
+
   DomStorageArea(int64 namespace_id,
                  const GURL& origin,
                  const FilePath& directory,
                  DomStorageTaskRunner* task_runner);
 
   const GURL& origin() const { return origin_; }
   int64 namespace_id() const { return namespace_id_; }
 
   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);
 
+  void Shutdown();
+
  private:
   FRIEND_TEST_ALL_PREFIXES(DomStorageAreaTest, DomStorageAreaBasics);
   FRIEND_TEST_ALL_PREFIXES(DomStorageAreaTest, BackingDatabaseOpened);
   FRIEND_TEST_ALL_PREFIXES(DomStorageAreaTest, TestDatabaseFilePath);
   friend class base::RefCountedThreadSafe<DomStorageArea>;
 
+  struct CommitBatch;
+
   // 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* GetCommitBatch();
+  void OnCommitTimer();
   void CommitChanges();
-
-  static FilePath DatabaseFileNameFromOrigin(const GURL& origin);
+  void OnCommitComplete();
+  void CommitShutdownChanges();
 
   ~DomStorageArea();
 
   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_