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// Copyright 2011 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef COMPONENTS_PREFS_PREF_NOTIFIER_IMPL_H_
#define COMPONENTS_PREFS_PREF_NOTIFIER_IMPL_H_
#include <list>
#include <memory>
#include <string>
#include <string_view>
#include <unordered_map>
#include "base/compiler_specific.h"
#include "base/functional/callback.h"
#include "base/memory/raw_ptr.h"
#include "base/observer_list.h"
#include "base/sequence_checker.h"
#include "components/prefs/pref_notifier.h"
#include "components/prefs/pref_observer.h"
#include "components/prefs/prefs_export.h"
#include "components/prefs/transparent_unordered_string_map.h"
class PrefService;
// The PrefNotifier implementation used by the PrefService.
class COMPONENTS_PREFS_EXPORT PrefNotifierImpl : public PrefNotifier {
public:
PrefNotifierImpl();
explicit PrefNotifierImpl(PrefService* pref_service);
PrefNotifierImpl(const PrefNotifierImpl&) = delete;
PrefNotifierImpl& operator=(const PrefNotifierImpl&) = delete;
~PrefNotifierImpl() override;
// If the pref at the given path changes, we call the observer's
// OnPreferenceChanged method.
void AddPrefObserver(std::string_view path, PrefObserver* observer);
void RemovePrefObserver(std::string_view path, PrefObserver* observer);
// These observers are called for any pref changes.
//
// AVOID ADDING THESE. See the long comment in the identically-named
// functions on PrefService for background.
void AddPrefObserverAllPrefs(PrefObserver* observer);
void RemovePrefObserverAllPrefs(PrefObserver* observer);
// We run the callback once, when initialization completes. The bool
// parameter will be set to true for successful initialization,
// false for unsuccessful.
void AddInitObserver(base::OnceCallback<void(bool)> observer);
void SetPrefService(PrefService* pref_service);
// PrefNotifier overrides.
void OnPreferenceChanged(std::string_view pref_name) override;
protected:
// PrefNotifier overrides.
void OnInitializationCompleted(bool succeeded) override;
// A map from pref names to a list of observers. Observers get fired in the
// order they are added. These should only be accessed externally for unit
// testing.
using PrefObserverList = base::ObserverList<PrefObserver>::Unchecked;
using PrefObserverMap = TransparentUnorderedStringMap<PrefObserverList>;
using PrefInitObserverList = std::list<base::OnceCallback<void(bool)>>;
const PrefObserverMap* pref_observers() const { return &pref_observers_; }
private:
// For the given pref_name, fire any observer of the pref. Virtual so it can
// be mocked for unit testing.
virtual void FireObservers(std::string_view path);
// Weak reference; the notifier is owned by the PrefService.
raw_ptr<PrefService> pref_service_;
PrefObserverMap pref_observers_;
PrefInitObserverList init_observers_;
// Observers for changes to any preference.
PrefObserverList all_prefs_pref_observers_;
SEQUENCE_CHECKER(sequence_checker_);
};
#endif // COMPONENTS_PREFS_PREF_NOTIFIER_IMPL_H_
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