SessionStorageDatabase: Allow writing data into a shallow copy.

webkit/dom_storage/session_storage_database.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_SESSION_STORAGE_DATABASE_H_
 #define WEBKIT_DOM_STORAGE_SESSION_STORAGE_DATABASE_H_
 #pragma once
 
 #include <map>
 #include <string>
@@ skipping 26 matching lines @@
   // assumed to be empty and any duplicate keys will be overwritten. If the
   // database exists on disk then it will be opened. If it does not exist then
   // it will not be created and |result| will be unmodified.
   void ReadAreaValues(int64 namespace_id,
                       const GURL& origin,
                       ValuesMap* result);
 
   // Updates the data for |namespace_id| and |origin|. Will remove all keys
   // before updating the database if |clear_all_first| is set. Then all entries
   // in |changes| will be examined - keys mapped to a null NullableString16 will
-  // be removed and all others will be inserted/updated as appropriate.
+  // be removed and all others will be inserted/updated as appropriate. It is
+  // allowed to write data into a shallow copy created by CloneNamespace, and in
+  // that case the copy will be made deep before writing the values.
   bool CommitAreaChanges(int64 namespace_id,
                          const GURL& origin,
                          bool clear_all_first,
                          const ValuesMap& changes);
 
   // Creates shallow copies of the areas for |namespace_id| and associates them
   // with |new_namespace_id|.
   bool CloneNamespace(int64 namespace_id, int64 new_namespace_id);
 
-  // Creates a deep copy of the area for |namespace_id| and |origin|.
-  bool DeepCopyArea(int64 namespace_id, const GURL& origin);
-
   // Deletes the data for |namespace_id| and |origin|.
   bool DeleteArea(int64 namespace_id, const GURL& origin);
 
   // Deletes the data for |namespace_id|.
   bool DeleteNamespace(int64 namespace_id);
 
  private:
   friend class base::RefCountedThreadSafe<SessionStorageDatabase>;
   friend class SessionStorageDatabaseTest;
 
@@ skipping 81 matching lines @@
                            leveldb::WriteBatch* batch);
   // Decreases the ref count of a map by |decrease|. If the ref count goes to 0,
   // deletes the map.
   bool DecreaseMapRefCount(const std::string& map_id,
                            int decrease,
                            leveldb::WriteBatch* batch);
 
   // Deletes all values in |map_id|.
   bool ClearMap(const std::string& map_id, leveldb::WriteBatch* batch);
 
+  // Breaks the association between (|namespace_id|, |origin|) and |map_id| and
+  // creates a new map for (|namespace_id|, |origin|). Copies the data from the
+  // old map if |copy_data| is true.
+  bool DeepCopyArea(int64 namespace_id,
+                    const GURL& origin,
+                    bool copy_data,
+                    std::string* map_id,
+                    leveldb::WriteBatch* batch);
+
   // Helper functions for creating the keys needed for the schema.
   static std::string NamespaceStartKey(const std::string& namespace_id_str);
   static std::string NamespaceStartKey(int64 namespace_id,
                                        int64 namespace_offset);
   static std::string NamespaceKey(const std::string& namespace_id_str,
                                   const std::string& origin);
   static std::string NamespaceKey(int64 namespace_id,
                                   int64 namespace_offset,
                                   const GURL& origin);
   static std::string NamespaceIdStr(int64 namespace_id, int64 namespace_offset);
@@ skipping 22 matching lines @@
   // the offset yet. The namespaces ids which are handled as strings (named
   // namesapce_id_str) contain the offset.
   int64 namespace_offset_;
 
   DISALLOW_COPY_AND_ASSIGN(SessionStorageDatabase);
 };
 
 }  // namespace dom_storage
 
 #endif  // WEBKIT_DOM_STORAGE_SESSION_STORAGE_DATABASE_H_