Create and store persistent unique ids for sessionStorage.

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_
 #pragma once
 
 #include <map>
 
@@ skipping 14 matching lines @@
     : public base::RefCountedThreadSafe<DomStorageNamespace> {
  public:
   // Constructor for a LocalStorage namespace with id of 0
   // and an optional backing directory on disk.
   DomStorageNamespace(const FilePath& directory,  // may be empty
                       DomStorageTaskRunner* task_runner);
 
   // Constructor for a SessionStorage namespace with a non-zero id
   // and no backing directory on disk.
   DomStorageNamespace(int64 namespace_id,
+                      const std::string& persistent_namespace_id,
                       DomStorageTaskRunner* task_runner);
 
   int64 namespace_id() const { return namespace_id_; }
+  std::string persistent_namespace_id() const {

[michaeln, 2012/06/14 22:53:48]

could the return value here be const string&

[marja, 2012/06/15 09:17:42]

I think so; it would be invalid if the string was used after the
DomStorageNamespace is deleted, but I don't think that would easily happen.

(const references keep temporaries alive, but in this case it wouldn't keep the
string which is|was a member variable alive any longer... right?)

+    return persistent_namespace_id_;
+  }
 
   // Returns the storage area for the given origin,
   // creating instance if needed. Each call to open
   // must be balanced with a call to CloseStorageArea.
   DomStorageArea* OpenStorageArea(const GURL& origin);
   void CloseStorageArea(DomStorageArea* area);
 
   // 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);
+  DomStorageNamespace* Clone(int64 clone_namespace_id,
+                             const std::string& clone_persistent_namespace_id);
 
   void DeleteOrigin(const GURL& origin);
   void PurgeMemory();
   void Shutdown();
 
  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);
     ~AreaHolder();
   };
   typedef std::map<GURL, AreaHolder> AreaMap;
 
   ~DomStorageNamespace();
 
   // Returns a pointer to the area holder in our map or NULL.
   AreaHolder* GetAreaHolder(const GURL& origin);
 
   int64 namespace_id_;
+  std::string persistent_namespace_id_;
   FilePath directory_;
   AreaMap areas_;
   scoped_refptr<DomStorageTaskRunner> task_runner_;
 };
 
 }  // namespace dom_storage
 
 
 #endif  // WEBKIT_DOM_STORAGE_DOM_STORAGE_NAMESPACE_H_