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.
5
#ifndef BASE_PREFS_OVERLAY_USER_PREF_STORE_H_
6
#define BASE_PREFS_OVERLAY_USER_PREF_STORE_H_
11
#include "base/basictypes.h"
12
#include "base/memory/ref_counted.h"
13
#include "base/observer_list.h"
14
#include "base/prefs/base_prefs_export.h"
15
#include "base/prefs/persistent_pref_store.h"
16
#include "base/prefs/pref_value_map.h"
18
// PersistentPrefStore that directs all write operations into an in-memory
19
// PrefValueMap. Read operations are first answered by the PrefValueMap.
20
// If the PrefValueMap does not contain a value for the requested key,
21
// the look-up is passed on to an underlying PersistentPrefStore |underlay_|.
22
class BASE_PREFS_EXPORT OverlayUserPrefStore : public PersistentPrefStore,
23
public PrefStore::Observer {
25
explicit OverlayUserPrefStore(PersistentPrefStore* underlay);
27
// Returns true if a value has been set for the |key| in this
28
// OverlayUserPrefStore, i.e. if it potentially overrides a value
29
// from the |underlay_|.
30
virtual bool IsSetInOverlay(const std::string& key) const;
32
// Methods of PrefStore.
33
virtual void AddObserver(PrefStore::Observer* observer) OVERRIDE;
34
virtual void RemoveObserver(PrefStore::Observer* observer) OVERRIDE;
35
virtual bool HasObservers() const OVERRIDE;
36
virtual bool IsInitializationComplete() const OVERRIDE;
37
virtual bool GetValue(const std::string& key,
38
const base::Value** result) const OVERRIDE;
40
// Methods of PersistentPrefStore.
41
virtual bool GetMutableValue(const std::string& key,
42
base::Value** result) OVERRIDE;
43
virtual void SetValue(const std::string& key, base::Value* value) OVERRIDE;
44
virtual void SetValueSilently(const std::string& key,
45
base::Value* value) OVERRIDE;
46
virtual void RemoveValue(const std::string& key) OVERRIDE;
47
virtual bool ReadOnly() const OVERRIDE;
48
virtual PrefReadError GetReadError() const OVERRIDE;
49
virtual PrefReadError ReadPrefs() OVERRIDE;
50
virtual void ReadPrefsAsync(ReadErrorDelegate* delegate) OVERRIDE;
51
virtual void CommitPendingWrite() OVERRIDE;
52
virtual void ReportValueChanged(const std::string& key) OVERRIDE;
54
// Methods of PrefStore::Observer.
55
virtual void OnPrefValueChanged(const std::string& key) OVERRIDE;
56
virtual void OnInitializationCompleted(bool succeeded) OVERRIDE;
58
void RegisterOverlayPref(const std::string& key);
59
void RegisterOverlayPref(const std::string& overlay_key,
60
const std::string& underlay_key);
63
virtual ~OverlayUserPrefStore();
66
typedef std::map<std::string, std::string> NamesMap;
68
const std::string& GetOverlayKey(const std::string& underlay_key) const;
69
const std::string& GetUnderlayKey(const std::string& overlay_key) const;
71
// Returns true if |key| corresponds to a preference that shall be stored in
72
// an in-memory PrefStore that is not persisted to disk.
73
bool ShallBeStoredInOverlay(const std::string& key) const;
75
ObserverList<PrefStore::Observer, true> observers_;
76
PrefValueMap overlay_;
77
scoped_refptr<PersistentPrefStore> underlay_;
78
NamesMap overlay_to_underlay_names_map_;
79
NamesMap underlay_to_overlay_names_map_;
81
DISALLOW_COPY_AND_ASSIGN(OverlayUserPrefStore);
84
#endif // BASE_PREFS_OVERLAY_USER_PREF_STORE_H_