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

webkit/dom_storage/dom_storage_types.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_TYPES_H_
 #define WEBKIT_DOM_STORAGE_DOM_STORAGE_TYPES_H_
 
 #include <map>
 
 #include "base/basictypes.h"
@@ skipping 12 matching lines @@
 // In the browser process we allow some overage to
 // accomodate concurrent writes from different renderers
 // that were allowed because the limit imposed in the renderer
 // wasn't exceeded.
 const size_t kPerAreaOverQuotaAllowance = 100 * 1024;
 
 // Value to indicate the localstorage namespace vs non-zero
 // values for sessionstorage namespaces.
 const int64 kLocalStorageNamespaceId = 0;
 
+// Max in-memory storage size.  One profile (i.e. one DomStorageContext)
+// should not hold in-memory data more than this.
+// TODO(kinuko,michaeln): Consider calling DomStorageArea::PurgeMemory
+// at a reasonable timing to keep the in-memory cache size rather than
+// rejecting incoming requests.
+const size_t kMaxInMemoryAreaSize = 512 * 1024 * 1024;
+
 const int64 kInvalidSessionStorageNamespaceId = kLocalStorageNamespaceId;
 
 // Value to indicate an area that not be opened.
 const int kInvalidAreaId = -1;
 
 typedef std::map<string16, NullableString16> ValuesMap;
 
 struct WEBKIT_STORAGE_EXPORT LocalStorageUsageInfo {
   GURL origin;
   size_t data_size;
   base::Time last_modified;
 
   LocalStorageUsageInfo();
   ~LocalStorageUsageInfo();
 };
 
 struct WEBKIT_STORAGE_EXPORT SessionStorageUsageInfo {
   GURL origin;
   std::string persistent_namespace_id;
 
   SessionStorageUsageInfo();
   ~SessionStorageUsageInfo();
 };
 
 }  // namespace dom_storage
 
 #endif  // WEBKIT_DOM_STORAGE_DOM_STORAGE_TYPES_H_