base/prefs/default_pref_store.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef BASE_PREFS_DEFAULT_PREF_STORE_H_
   6 #define BASE_PREFS_DEFAULT_PREF_STORE_H_
   7
   8 #include <string>
   9
  10 #include "base/observer_list.h"
  11 #include "base/prefs/base_prefs_export.h"
  12 #include "base/prefs/pref_store.h"
  13 #include "base/prefs/pref_value_map.h"
  14 #include "base/values.h"
  15
  16 // Used within a PrefRegistry to keep track of default preference values.
  17 class BASE_PREFS_EXPORT DefaultPrefStore : public PrefStore {
  18  public:
  19   typedef PrefValueMap::const_iterator const_iterator;
  20
  21   DefaultPrefStore();
  22
  23   // PrefStore implementation:
  24   bool GetValue(const std::string& key,
  25                 const base::Value** result) const override;
  26   void AddObserver(PrefStore::Observer* observer) override;
  27   void RemoveObserver(PrefStore::Observer* observer) override;
  28   bool HasObservers() const override;
  29
  30   // Sets a |value| for |key|. Should only be called if a value has not been
  31   // set yet; otherwise call ReplaceDefaultValue().
  32   void SetDefaultValue(const std::string& key, scoped_ptr<base::Value> value);
  33
  34   // Replaces the the value for |key| with a new value. Should only be called
  35   // if a value has alreday been set; otherwise call SetDefaultValue().
  36   void ReplaceDefaultValue(const std::string& key,
  37                            scoped_ptr<base::Value> value);
  38
  39   const_iterator begin() const;
  40   const_iterator end() const;
  41
  42  private:
  43   ~DefaultPrefStore() override;
  44
  45   PrefValueMap prefs_;
  46
  47   ObserverList<PrefStore::Observer, true> observers_;
  48
  49   DISALLOW_COPY_AND_ASSIGN(DefaultPrefStore);
  50 };
  51
  52 #endif  // BASE_PREFS_DEFAULT_PREF_STORE_H_