DomStorage data deletion and memory purging.

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 11 matching lines @@
 
 // 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 const FilePath::CharType kDatabaseFileExtension[];
   static FilePath DatabaseFileNameFromOrigin(const GURL& origin);
+  static GURL OriginFromDatabaseFileName(const FilePath& file_name);
 
   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);
 
+  bool HasUncommittedChanges() const;
+
+  // Similar to Clear() but more optimized for just deleting
+  // without raising events.
+  void DeleteOrigin();
+
+  // Frees up memory when possible. Typically, this method returns
+  // the object to its just constructed state, however if uncommitted
+  // changes are pending, it does nothing.
+  void PurgeMemory();
+
   // 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_TEST_ALL_PREFIXES(DomStorageAreaTest, DeleteOrigin);
+  FRIEND_TEST_ALL_PREFIXES(DomStorageAreaTest, PurgeMemory);
   friend class base::RefCountedThreadSafe<DomStorageArea>;
 
   struct CommitBatch {
     bool clear_all_first;
     ValuesMap changed_values;
     CommitBatch();
     ~CommitBatch();
   };
 
   ~DomStorageArea();
@@ skipping 21 matching lines @@
   scoped_ptr<DomStorageDatabase> backing_;
   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_