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

webkit/dom_storage/dom_storage_context.cc

 // 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.
 
 #include "webkit/dom_storage/dom_storage_context.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/file_util.h"
 #include "base/guid.h"
@@ skipping 334 matching lines @@
 }
 
 void DomStorageContext::StartScavengingUnusedSessionStorage() {
   if (session_storage_database_.get()) {
     task_runner_->PostDelayedTask(
         FROM_HERE, base::Bind(&DomStorageContext::FindUnusedNamespaces, this),
         base::TimeDelta::FromSeconds(kSessionStoraceScavengingSeconds));
   }
 }
 
+int64 DomStorageContext::GetInMemoryStorageSize() const {
+  // TODO(kinuko): Cache this!!
+  int64 total_size = 0;
+  // Naively add-up the area size for each connection.
+  std::set<DomStorageArea*> visited_areas;
+  for (StorageNamespaceMap::const_iterator itr = namespaces_.begin();
+       itr != namespaces_.end(); ++itr) {
+    const DomStorageNamespace::AreaMap& map = itr->second->GetAreaMap();
+    for (DomStorageNamespace::AreaMap::const_iterator map_itr = map.begin();
+         map_itr != map.end(); ++map_itr) {
+      // We don't care open_count_ here, since we want to limit the
+      // memory usage.
+      DomStorageArea* area = map_itr->second.area_;
+      DCHECK(area);
+      if (visited_areas.insert(area).second) {
+        total_size += area->GetMapSize();
+      }
+    }
+  }
+  return total_size;
+}
+
 void DomStorageContext::FindUnusedNamespaces() {
   DCHECK(session_storage_database_.get());
   if (scavenging_started_)
     return;
   scavenging_started_ = true;
   std::set<std::string> namespace_ids_in_use;
   for (StorageNamespaceMap::const_iterator it = namespaces_.begin();
        it != namespaces_.end(); ++it)
     namespace_ids_in_use.insert(it->second->persistent_namespace_id());
   std::set<std::string> protected_persistent_session_ids;
@@ skipping 50 matching lines @@
   if (!deletable_persistent_namespace_ids_.empty()) {
     task_runner_->PostDelayedTask(
         FROM_HERE, base::Bind(
             &DomStorageContext::DeleteNextUnusedNamespace,
             this),
         base::TimeDelta::FromSeconds(kSessionStoraceScavengingSeconds));
   }
 }
 
 }  // namespace dom_storage