Sanitize PrefStore interface.

chrome/browser/prefs/pref_value_map.h

+// Copyright (c) 2010 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 CHROME_BROWSER_PREFS_PREF_VALUE_MAP_H_
+#define CHROME_BROWSER_PREFS_PREF_VALUE_MAP_H_
+#pragma once
+
+#include <map>
+#include <string>
+
+#include "base/basictypes.h"
+
+class Value;
+
+// A generic string to value map used by the PrefStore implementations.
+class PrefValueMap {
+ public:
+  PrefValueMap() {}
+  virtual ~PrefValueMap();
+
+  // Gets the value for |key| and stores it in |value|. Ownership remains with
+  // the map. Returns true if a value is present. If not, |value| is not
+  // touched.
+  bool GetValue(const std::string& key, Value** value) const;
+
+  // Sets a new |value| for |key|. Takes ownership of |value|, which must be
+  // non-NULL. Returns true if the value changed.
+  bool SetValue(const std::string& key, Value* value);
+
+  // Removes the value for |key| from the map. Returns true if a value was
+  // removed.
+  bool RemoveValue(const std::string& key);
+
+  // Clears the map.
+  void Clear();
+
+ private:
+  typedef std::map<std::string, Value*> Map;
+
+  Map prefs_;
+
+  DISALLOW_COPY_AND_ASSIGN(PrefValueMap);
+};
+
+#endif  // CHROME_BROWSER_PREFS_PREF_VALUE_MAP_H_