base/prefs/overlay_user_pref_store.cc

   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 #include "base/prefs/overlay_user_pref_store.h"
   6
   7 #include "base/memory/scoped_ptr.h"
   8 #include "base/values.h"
   9
  10 OverlayUserPrefStore::OverlayUserPrefStore(
  11     PersistentPrefStore* underlay)
  12     : underlay_(underlay) {
  13   underlay_->AddObserver(this);
  14 }
  15
  16 bool OverlayUserPrefStore::IsSetInOverlay(const std::string& key) const {
  17   return overlay_.GetValue(key, NULL);
  18 }
  19
  20 void OverlayUserPrefStore::AddObserver(PrefStore::Observer* observer) {
  21   observers_.AddObserver(observer);
  22 }
  23
  24 void OverlayUserPrefStore::RemoveObserver(PrefStore::Observer* observer) {
  25   observers_.RemoveObserver(observer);
  26 }
  27
  28 bool OverlayUserPrefStore::HasObservers() const {
  29   return observers_.might_have_observers();
  30 }
  31
  32 bool OverlayUserPrefStore::IsInitializationComplete() const {
  33   return underlay_->IsInitializationComplete();
  34 }
  35
  36 bool OverlayUserPrefStore::GetValue(const std::string& key,
  37                                     const base::Value** result) const {
  38   // If the |key| shall NOT be stored in the overlay store, there must not
  39   // be an entry.
  40   DCHECK(ShallBeStoredInOverlay(key) || !overlay_.GetValue(key, NULL));
  41
  42   if (overlay_.GetValue(key, result))
  43     return true;
  44   return underlay_->GetValue(GetUnderlayKey(key), result);
  45 }
  46
  47 bool OverlayUserPrefStore::GetMutableValue(const std::string& key,
  48                                            base::Value** result) {
  49   if (!ShallBeStoredInOverlay(key))
  50     return underlay_->GetMutableValue(GetUnderlayKey(key), result);
  51
  52   if (overlay_.GetValue(key, result))
  53     return true;
  54
  55   // Try to create copy of underlay if the overlay does not contain a value.
  56   base::Value* underlay_value = NULL;
  57   if (!underlay_->GetMutableValue(GetUnderlayKey(key), &underlay_value))
  58     return false;
  59
  60   *result = underlay_value->DeepCopy();
  61   overlay_.SetValue(key, *result);
  62   return true;
  63 }
  64
  65 void OverlayUserPrefStore::SetValue(const std::string& key,
  66                                     base::Value* value) {
  67   if (!ShallBeStoredInOverlay(key)) {
  68     underlay_->SetValue(GetUnderlayKey(key), value);
  69     return;
  70   }
  71
  72   if (overlay_.SetValue(key, value))
  73     ReportValueChanged(key);
  74 }
  75
  76 void OverlayUserPrefStore::SetValueSilently(const std::string& key,
  77                                             base::Value* value) {
  78   if (!ShallBeStoredInOverlay(key)) {
  79     underlay_->SetValueSilently(GetUnderlayKey(key), value);
  80     return;
  81   }
  82
  83   overlay_.SetValue(key, value);
  84 }
  85
  86 void OverlayUserPrefStore::RemoveValue(const std::string& key) {
  87   if (!ShallBeStoredInOverlay(key)) {
  88     underlay_->RemoveValue(GetUnderlayKey(key));
  89     return;
  90   }
  91
  92   if (overlay_.RemoveValue(key))
  93     ReportValueChanged(key);
  94 }
  95
  96 bool OverlayUserPrefStore::ReadOnly() const {
  97   return false;
  98 }
  99
 100 PersistentPrefStore::PrefReadError OverlayUserPrefStore::GetReadError() const {
 101   return PersistentPrefStore::PREF_READ_ERROR_NONE;
 102 }
 103
 104 PersistentPrefStore::PrefReadError OverlayUserPrefStore::ReadPrefs() {
 105   // We do not read intentionally.
 106   OnInitializationCompleted(true);
 107   return PersistentPrefStore::PREF_READ_ERROR_NONE;
 108 }
 109
 110 void OverlayUserPrefStore::ReadPrefsAsync(
 111     ReadErrorDelegate* error_delegate_raw) {
 112   scoped_ptr<ReadErrorDelegate> error_delegate(error_delegate_raw);
 113   // We do not read intentionally.
 114   OnInitializationCompleted(true);
 115 }
 116
 117 void OverlayUserPrefStore::CommitPendingWrite() {
 118   underlay_->CommitPendingWrite();
 119   // We do not write our content intentionally.
 120 }
 121
 122 void OverlayUserPrefStore::ReportValueChanged(const std::string& key) {
 123   FOR_EACH_OBSERVER(PrefStore::Observer, observers_, OnPrefValueChanged(key));
 124 }
 125
 126 void OverlayUserPrefStore::OnPrefValueChanged(const std::string& key) {
 127   if (!overlay_.GetValue(GetOverlayKey(key), NULL))
 128     ReportValueChanged(GetOverlayKey(key));
 129 }
 130
 131 void OverlayUserPrefStore::OnInitializationCompleted(bool succeeded) {
 132   FOR_EACH_OBSERVER(PrefStore::Observer, observers_,
 133                     OnInitializationCompleted(succeeded));
 134 }
 135
 136 void OverlayUserPrefStore::RegisterOverlayPref(const std::string& key) {
 137   RegisterOverlayPref(key, key);
 138 }
 139
 140 void OverlayUserPrefStore::RegisterOverlayPref(
 141     const std::string& overlay_key,
 142     const std::string& underlay_key) {
 143   DCHECK(!overlay_key.empty()) << "Overlay key is empty";
 144   DCHECK(overlay_to_underlay_names_map_.find(overlay_key) ==
 145          overlay_to_underlay_names_map_.end()) <<
 146       "Overlay key already registered";
 147   DCHECK(!underlay_key.empty()) << "Underlay key is empty";
 148   DCHECK(underlay_to_overlay_names_map_.find(underlay_key) ==
 149          underlay_to_overlay_names_map_.end()) <<
 150       "Underlay key already registered";
 151   overlay_to_underlay_names_map_[overlay_key] = underlay_key;
 152   underlay_to_overlay_names_map_[underlay_key] = overlay_key;
 153 }
 154
 155 OverlayUserPrefStore::~OverlayUserPrefStore() {
 156   underlay_->RemoveObserver(this);
 157 }
 158
 159 const std::string& OverlayUserPrefStore::GetOverlayKey(
 160     const std::string& underlay_key) const {
 161   NamesMap::const_iterator i =
 162       underlay_to_overlay_names_map_.find(underlay_key);
 163   return i != underlay_to_overlay_names_map_.end() ? i->second : underlay_key;
 164 }
 165
 166 const std::string& OverlayUserPrefStore::GetUnderlayKey(
 167     const std::string& overlay_key) const {
 168   NamesMap::const_iterator i =
 169       overlay_to_underlay_names_map_.find(overlay_key);
 170   return i != overlay_to_underlay_names_map_.end() ? i->second : overlay_key;
 171 }
 172
 173 bool OverlayUserPrefStore::ShallBeStoredInOverlay(
 174     const std::string& key) const {
 175   return overlay_to_underlay_names_map_.find(key) !=
 176       overlay_to_underlay_names_map_.end();
 177 }