1 // Copyright (c) 2011 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 CHROME_BROWSER_PREFS_OVERLAY_PERSISTENT_PREF_STORE_H_ 6 #define CHROME_BROWSER_PREFS_OVERLAY_PERSISTENT_PREF_STORE_H_ 7 #pragma once 8 9 #include <string> 10 11 #include "base/basictypes.h" 12 #include "base/memory/ref_counted.h" 13 #include "base/observer_list.h" 14 #include "chrome/browser/prefs/pref_value_map.h" 15 #include "chrome/common/persistent_pref_store.h" 16 17 // PersistentPrefStore that directs all write operations into a in-memory 18 // PrefValueMap. Read operations are first answered by the PrefValueMap. 19 // If the PrefValueMap does not contain a value for the requested key, 20 // the look-up is passed on to an underlying PersistentPrefStore |underlay_|. 21 class OverlayPersistentPrefStore : public PersistentPrefStore, 22 public PrefStore::Observer { 23 public: 24 explicit OverlayPersistentPrefStore(PersistentPrefStore* underlay); 25 virtual ~OverlayPersistentPrefStore(); 26 27 // Returns true if a value has been set for the |key| in this 28 // OverlayPersistentPrefStore, i.e. if it potentially overrides a value 29 // from the |underlay_|. 30 virtual bool IsSetInOverlay(const std::string& key) const; 31 32 // Methods of PrefStore. 33 virtual void AddObserver(PrefStore::Observer* observer); 34 virtual void RemoveObserver(PrefStore::Observer* observer); 35 virtual bool IsInitializationComplete() const; 36 virtual ReadResult GetValue(const std::string& key, 37 const Value** result) const; 38 39 // Methods of PersistentPrefStore. 40 virtual ReadResult GetMutableValue(const std::string& key, Value** result); 41 virtual void SetValue(const std::string& key, Value* value); 42 virtual void SetValueSilently(const std::string& key, Value* value); 43 virtual void RemoveValue(const std::string& key); 44 virtual bool ReadOnly() const; 45 virtual PrefReadError ReadPrefs(); 46 virtual bool WritePrefs(); 47 virtual void ScheduleWritePrefs(); 48 virtual void CommitPendingWrite(); 49 virtual void ReportValueChanged(const std::string& key); 50 51 private: 52 // Methods of PrefStore::Observer. 53 virtual void OnPrefValueChanged(const std::string& key); 54 virtual void OnInitializationCompleted(); 55 56 ObserverList<PrefStore::Observer, true> observers_; 57 PrefValueMap overlay_; 58 scoped_refptr<PersistentPrefStore> underlay_; 59 60 DISALLOW_COPY_AND_ASSIGN(OverlayPersistentPrefStore); 61 }; 62 63 #endif // CHROME_BROWSER_PREFS_OVERLAY_PERSISTENT_PREF_STORE_H_ 64