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      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 #include "chrome/browser/prefs/overlay_persistent_pref_store.h"
      6 
      7 #include "base/values.h"
      8 
      9 OverlayPersistentPrefStore::OverlayPersistentPrefStore(
     10     PersistentPrefStore* underlay)
     11     : underlay_(underlay) {
     12   underlay_->AddObserver(this);
     13 }
     14 OverlayPersistentPrefStore::~OverlayPersistentPrefStore() {
     15   underlay_->RemoveObserver(this);
     16 }
     17 
     18 bool OverlayPersistentPrefStore::IsSetInOverlay(const std::string& key) const {
     19   return overlay_.GetValue(key, NULL);
     20 }
     21 
     22 void OverlayPersistentPrefStore::AddObserver(PrefStore::Observer* observer) {
     23   observers_.AddObserver(observer);
     24 }
     25 
     26 void OverlayPersistentPrefStore::RemoveObserver(PrefStore::Observer* observer) {
     27   observers_.RemoveObserver(observer);
     28 }
     29 
     30 bool OverlayPersistentPrefStore::IsInitializationComplete() const {
     31   return underlay_->IsInitializationComplete();
     32 }
     33 
     34 PrefStore::ReadResult OverlayPersistentPrefStore::GetValue(
     35     const std::string& key,
     36     const Value** result) const {
     37   if (overlay_.GetValue(key, result))
     38     return READ_OK;
     39   return underlay_->GetValue(key, result);
     40 }
     41 
     42 PrefStore::ReadResult OverlayPersistentPrefStore::GetMutableValue(
     43     const std::string& key,
     44     Value** result) {
     45   if (overlay_.GetValue(key, result))
     46     return READ_OK;
     47 
     48   // Try to create copy of underlay if the overlay does not contain a value.
     49   Value* underlay_value = NULL;
     50   PrefStore::ReadResult read_result =
     51       underlay_->GetMutableValue(key, &underlay_value);
     52   if (read_result == READ_OK) {
     53     *result = underlay_value->DeepCopy();
     54     overlay_.SetValue(key, *result);
     55     return READ_OK;
     56   }
     57   // Return read failure if underlay stores no value for |key|.
     58   return read_result;
     59 }
     60 
     61 void OverlayPersistentPrefStore::SetValue(const std::string& key,
     62                                           Value* value) {
     63   if (overlay_.SetValue(key, value))
     64     FOR_EACH_OBSERVER(PrefStore::Observer, observers_, OnPrefValueChanged(key));
     65 }
     66 
     67 void OverlayPersistentPrefStore::SetValueSilently(const std::string& key,
     68                                                   Value* value) {
     69   overlay_.SetValue(key, value);
     70 }
     71 
     72 void OverlayPersistentPrefStore::RemoveValue(const std::string& key) {
     73   if (overlay_.RemoveValue(key))
     74     FOR_EACH_OBSERVER(PrefStore::Observer, observers_, OnPrefValueChanged(key));
     75 }
     76 
     77 bool OverlayPersistentPrefStore::ReadOnly() const {
     78   return false;
     79 }
     80 
     81 PersistentPrefStore::PrefReadError OverlayPersistentPrefStore::ReadPrefs() {
     82   // We do not read intentionally.
     83   return PersistentPrefStore::PREF_READ_ERROR_NONE;
     84 }
     85 
     86 bool OverlayPersistentPrefStore::WritePrefs() {
     87   // We do not write intentionally.
     88   return true;
     89 }
     90 
     91 void OverlayPersistentPrefStore::ScheduleWritePrefs() {
     92   // We do not write intentionally.
     93 }
     94 
     95 void OverlayPersistentPrefStore::CommitPendingWrite() {
     96   // We do not write intentionally.
     97 }
     98 
     99 void OverlayPersistentPrefStore::ReportValueChanged(const std::string& key) {
    100   FOR_EACH_OBSERVER(PrefStore::Observer, observers_, OnPrefValueChanged(key));
    101 }
    102 
    103 void OverlayPersistentPrefStore::OnPrefValueChanged(const std::string& key) {
    104   if (!overlay_.GetValue(key, NULL))
    105     FOR_EACH_OBSERVER(PrefStore::Observer, observers_, OnPrefValueChanged(key));
    106 }
    107 
    108 void OverlayPersistentPrefStore::OnInitializationCompleted() {
    109   FOR_EACH_OBSERVER(PrefStore::Observer, observers_,
    110                     OnInitializationCompleted());
    111 }
    112