root/base/prefs/overlay_user_pref_store.cc

DEFINITIONS

1. IsSetInOverlay
2. AddObserver
3. RemoveObserver
4. HasObservers
5. IsInitializationComplete
6. GetValue
7. GetMutableValue
8. SetValue
9. SetValueSilently
10. RemoveValue
11. ReadOnly
12. GetReadError
13. ReadPrefs
14. ReadPrefsAsync
15. CommitPendingWrite
16. ReportValueChanged
17. OnPrefValueChanged
18. OnInitializationCompleted
19. RegisterOverlayPref
20. RegisterOverlayPref
21. GetOverlayKey
22. GetUnderlayKey
23. ShallBeStoredInOverlay

// 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.

#include "base/prefs/overlay_user_pref_store.h"

#include "base/memory/scoped_ptr.h"
#include "base/values.h"

OverlayUserPrefStore::OverlayUserPrefStore(
    PersistentPrefStore* underlay)
    : underlay_(underlay) {
  underlay_->AddObserver(this);
}

bool OverlayUserPrefStore::IsSetInOverlay(const std::string& key) const {
  return overlay_.GetValue(key, NULL);
}

void OverlayUserPrefStore::AddObserver(PrefStore::Observer* observer) {
  observers_.AddObserver(observer);
}

void OverlayUserPrefStore::RemoveObserver(PrefStore::Observer* observer) {
  observers_.RemoveObserver(observer);
}

bool OverlayUserPrefStore::HasObservers() const {
  return observers_.might_have_observers();
}

bool OverlayUserPrefStore::IsInitializationComplete() const {
  return underlay_->IsInitializationComplete();
}

bool OverlayUserPrefStore::GetValue(const std::string& key,
                                    const base::Value** result) const {
  // If the |key| shall NOT be stored in the overlay store, there must not
  // be an entry.
  DCHECK(ShallBeStoredInOverlay(key) || !overlay_.GetValue(key, NULL));

  if (overlay_.GetValue(key, result))
    return true;
  return underlay_->GetValue(GetUnderlayKey(key), result);
}

bool OverlayUserPrefStore::GetMutableValue(const std::string& key,
                                           base::Value** result) {
  if (!ShallBeStoredInOverlay(key))
    return underlay_->GetMutableValue(GetUnderlayKey(key), result);

  if (overlay_.GetValue(key, result))
    return true;

  // Try to create copy of underlay if the overlay does not contain a value.
  base::Value* underlay_value = NULL;
  if (!underlay_->GetMutableValue(GetUnderlayKey(key), &underlay_value))
    return false;

  *result = underlay_value->DeepCopy();
  overlay_.SetValue(key, *result);
  return true;
}

void OverlayUserPrefStore::SetValue(const std::string& key,
                                    base::Value* value) {
  if (!ShallBeStoredInOverlay(key)) {
    underlay_->SetValue(GetUnderlayKey(key), value);
    return;
  }

  if (overlay_.SetValue(key, value))
    ReportValueChanged(key);
}

void OverlayUserPrefStore::SetValueSilently(const std::string& key,
                                            base::Value* value) {
  if (!ShallBeStoredInOverlay(key)) {
    underlay_->SetValueSilently(GetUnderlayKey(key), value);
    return;
  }

  overlay_.SetValue(key, value);
}

void OverlayUserPrefStore::RemoveValue(const std::string& key) {
  if (!ShallBeStoredInOverlay(key)) {
    underlay_->RemoveValue(GetUnderlayKey(key));
    return;
  }

  if (overlay_.RemoveValue(key))
    ReportValueChanged(key);
}

bool OverlayUserPrefStore::ReadOnly() const {
  return false;
}

PersistentPrefStore::PrefReadError OverlayUserPrefStore::GetReadError() const {
  return PersistentPrefStore::PREF_READ_ERROR_NONE;
}

PersistentPrefStore::PrefReadError OverlayUserPrefStore::ReadPrefs() {
  // We do not read intentionally.
  OnInitializationCompleted(true);
  return PersistentPrefStore::PREF_READ_ERROR_NONE;
}

void OverlayUserPrefStore::ReadPrefsAsync(
    ReadErrorDelegate* error_delegate_raw) {
  scoped_ptr<ReadErrorDelegate> error_delegate(error_delegate_raw);
  // We do not read intentionally.
  OnInitializationCompleted(true);
}

void OverlayUserPrefStore::CommitPendingWrite() {
  underlay_->CommitPendingWrite();
  // We do not write our content intentionally.
}

void OverlayUserPrefStore::ReportValueChanged(const std::string& key) {
  FOR_EACH_OBSERVER(PrefStore::Observer, observers_, OnPrefValueChanged(key));
}

void OverlayUserPrefStore::OnPrefValueChanged(const std::string& key) {
  if (!overlay_.GetValue(GetOverlayKey(key), NULL))
    ReportValueChanged(GetOverlayKey(key));
}

void OverlayUserPrefStore::OnInitializationCompleted(bool succeeded) {
  FOR_EACH_OBSERVER(PrefStore::Observer, observers_,
                    OnInitializationCompleted(succeeded));
}

void OverlayUserPrefStore::RegisterOverlayPref(const std::string& key) {
  RegisterOverlayPref(key, key);
}

void OverlayUserPrefStore::RegisterOverlayPref(
    const std::string& overlay_key,
    const std::string& underlay_key) {
  DCHECK(!overlay_key.empty()) << "Overlay key is empty";
  DCHECK(overlay_to_underlay_names_map_.find(overlay_key) ==
         overlay_to_underlay_names_map_.end()) <<
      "Overlay key already registered";
  DCHECK(!underlay_key.empty()) << "Underlay key is empty";
  DCHECK(underlay_to_overlay_names_map_.find(underlay_key) ==
         underlay_to_overlay_names_map_.end()) <<
      "Underlay key already registered";
  overlay_to_underlay_names_map_[overlay_key] = underlay_key;
  underlay_to_overlay_names_map_[underlay_key] = overlay_key;
}

OverlayUserPrefStore::~OverlayUserPrefStore() {
  underlay_->RemoveObserver(this);
}

const std::string& OverlayUserPrefStore::GetOverlayKey(
    const std::string& underlay_key) const {
  NamesMap::const_iterator i =
      underlay_to_overlay_names_map_.find(underlay_key);
  return i != underlay_to_overlay_names_map_.end() ? i->second : underlay_key;
}

const std::string& OverlayUserPrefStore::GetUnderlayKey(
    const std::string& overlay_key) const {
  NamesMap::const_iterator i =
      overlay_to_underlay_names_map_.find(overlay_key);
  return i != overlay_to_underlay_names_map_.end() ? i->second : overlay_key;
}

bool OverlayUserPrefStore::ShallBeStoredInOverlay(
    const std::string& key) const {
  return overlay_to_underlay_names_map_.find(key) !=
      overlay_to_underlay_names_map_.end();
}