| // 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 BASE_PREFS_OVERLAY_USER_PREF_STORE_H_ |
| #define BASE_PREFS_OVERLAY_USER_PREF_STORE_H_ |
| |
| #include <map> |
| #include <string> |
| |
| #include "base/basictypes.h" |
| #include "base/memory/ref_counted.h" |
| #include "base/observer_list.h" |
| #include "base/prefs/base_prefs_export.h" |
| #include "base/prefs/persistent_pref_store.h" |
| #include "base/prefs/pref_value_map.h" |
| |
| // PersistentPrefStore that directs all write operations into an in-memory |
| // PrefValueMap. Read operations are first answered by the PrefValueMap. |
| // If the PrefValueMap does not contain a value for the requested key, |
| // the look-up is passed on to an underlying PersistentPrefStore |underlay_|. |
| class BASE_PREFS_EXPORT OverlayUserPrefStore : public PersistentPrefStore, |
| public PrefStore::Observer { |
| public: |
| explicit OverlayUserPrefStore(PersistentPrefStore* underlay); |
| |
| // Returns true if a value has been set for the |key| in this |
| // OverlayUserPrefStore, i.e. if it potentially overrides a value |
| // from the |underlay_|. |
| virtual bool IsSetInOverlay(const std::string& key) const; |
| |
| // Methods of PrefStore. |
| void AddObserver(PrefStore::Observer* observer) override; |
| void RemoveObserver(PrefStore::Observer* observer) override; |
| bool HasObservers() const override; |
| bool IsInitializationComplete() const override; |
| bool GetValue(const std::string& key, |
| const base::Value** result) const override; |
| |
| // Methods of PersistentPrefStore. |
| bool GetMutableValue(const std::string& key, base::Value** result) override; |
| void SetValue(const std::string& key, |
| scoped_ptr<base::Value> value, |
| uint32 flags) override; |
| void SetValueSilently(const std::string& key, |
| scoped_ptr<base::Value> value, |
| uint32 flags) override; |
| void RemoveValue(const std::string& key, uint32 flags) override; |
| bool ReadOnly() const override; |
| PrefReadError GetReadError() const override; |
| PrefReadError ReadPrefs() override; |
| void ReadPrefsAsync(ReadErrorDelegate* delegate) override; |
| void CommitPendingWrite() override; |
| void SchedulePendingLossyWrites() override; |
| void ReportValueChanged(const std::string& key, uint32 flags) override; |
| |
| // Methods of PrefStore::Observer. |
| void OnPrefValueChanged(const std::string& key) override; |
| void OnInitializationCompleted(bool succeeded) override; |
| |
| void RegisterOverlayPref(const std::string& key); |
| void RegisterOverlayPref(const std::string& overlay_key, |
| const std::string& underlay_key); |
| |
| protected: |
| ~OverlayUserPrefStore() override; |
| |
| private: |
| typedef std::map<std::string, std::string> NamesMap; |
| |
| const std::string& GetOverlayKey(const std::string& underlay_key) const; |
| const std::string& GetUnderlayKey(const std::string& overlay_key) const; |
| |
| // Returns true if |key| corresponds to a preference that shall be stored in |
| // an in-memory PrefStore that is not persisted to disk. |
| bool ShallBeStoredInOverlay(const std::string& key) const; |
| |
| base::ObserverList<PrefStore::Observer, true> observers_; |
| PrefValueMap overlay_; |
| scoped_refptr<PersistentPrefStore> underlay_; |
| NamesMap overlay_to_underlay_names_map_; |
| NamesMap underlay_to_overlay_names_map_; |
| |
| DISALLOW_COPY_AND_ASSIGN(OverlayUserPrefStore); |
| }; |
| |
| #endif // BASE_PREFS_OVERLAY_USER_PREF_STORE_H_ |