Purge in-memory localStorage areas if the # of areas exceeds the limit

webkit/dom_storage/dom_storage_namespace.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_NAMESPACE_H_
 #define WEBKIT_DOM_STORAGE_DOM_STORAGE_NAMESPACE_H_
 
 #include <map>
 
 #include "base/basictypes.h"
@@ skipping 41 matching lines @@
   DomStorageArea* GetOpenStorageArea(const GURL& origin);
 
   // Creates a clone of |this| namespace including
   // shallow copies of all contained areas.
   // Should only be called for session storage namespaces.
   DomStorageNamespace* Clone(int64 clone_namespace_id,
                              const std::string& clone_persistent_namespace_id);
 
   void DeleteLocalStorageOrigin(const GURL& origin);
   void DeleteSessionStorageOrigin(const GURL& origin);
+  void PurgeUnopenedAreas();
   void PurgeMemory();
   void Shutdown();
 
+  unsigned int CountInMemoryAreas() const { return areas_.size(); }

[michaeln, 2013/04/05 23:39:23]

Unfortunately, I don't think this is an accurate count. There can be 'areas' in
the set that are not loaded into memory (as in after the existing PurgeMemory()
method has been called).

[kinuko, 2013/04/10 07:04:14]

Good point, I changed the code to iterate over areas_ to count up areas who have
in-memory data. (Is there a better way to do this?)

+
  private:
   friend class base::RefCountedThreadSafe<DomStorageNamespace>;
 
   // Struct to hold references to our contained areas and
   // to keep track of how many tabs have a given area open.
   struct AreaHolder {
     scoped_refptr<DomStorageArea> area_;
     int open_count_;
     AreaHolder();
     AreaHolder(DomStorageArea* area, int count);
@@ skipping 11 matching lines @@
   base::FilePath directory_;
   AreaMap areas_;
   scoped_refptr<DomStorageTaskRunner> task_runner_;
   scoped_refptr<SessionStorageDatabase> session_storage_database_;
 };
 
 }  // namespace dom_storage
 
 
 #endif  // WEBKIT_DOM_STORAGE_DOM_STORAGE_NAMESPACE_H_