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// Copyright (c) 2010 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.
#ifndef CHROME_BROWSER_PREF_NOTIFIER_H_
#define CHROME_BROWSER_PREF_NOTIFIER_H_
#pragma once
#include <string>
#include <vector>
#include "base/hash_tables.h"
#include "base/non_thread_safe.h"
#include "base/observer_list.h"
#include "chrome/common/notification_observer.h"
#include "chrome/common/notification_registrar.h"
class NotificationObserver;
class PrefService;
class PrefValueStore;
class Value;
// Registers observers for particular preferences and sends notifications when
// preference values or sources (i.e., which preference layer controls the
// preference) change.
class PrefNotifier : public NonThreadSafe,
public NotificationObserver {
public:
// PrefStores must be listed here in order from highest to lowest priority.
// MANAGED contains all managed (policy) preference values.
// EXTENSION contains preference values set by extensions.
// COMMAND_LINE contains preference values set by command-line switches.
// USER contains all user-set preference values.
// RECOMMENDED contains all recommended (policy) preference values.
// This enum is kept in pref_notifier.h rather than pref_value_store.h in
// order to minimize additional headers needed by the *PrefStore files.
enum PrefStoreType {
// INVALID_STORE is not associated with an actual PrefStore but used as
// an invalid marker, e.g. as a return value.
INVALID_STORE = -1,
MANAGED_STORE = 0,
EXTENSION_STORE,
COMMAND_LINE_STORE,
USER_STORE,
RECOMMENDED_STORE,
PREF_STORE_TYPE_MAX = RECOMMENDED_STORE
};
// The |service| with which this notifier is associated will be sent as the
// source of any notifications.
PrefNotifier(PrefService* service, PrefValueStore* value_store);
virtual ~PrefNotifier();
// For the given pref_name, fire any observer of the pref if |old_value| is
// different from the current value, or if the store controlling the value
// has changed.
// TODO(pamg): Currently notifies in some cases when it shouldn't. See
// comments for PrefHasChanged() in pref_value_store.h.
void OnPreferenceSet(const char* pref_name,
PrefNotifier::PrefStoreType new_store,
const Value* old_value);
// Convenience method to be called when a preference is set in the
// USER_STORE. See OnPreferenceSet().
void OnUserPreferenceSet(const char* pref_name, const Value* old_value);
// For the given pref_name, fire any observer of the pref. Virtual so it can
// be mocked for unit testing.
virtual void FireObservers(const char* path);
// If the pref at the given path changes, we call the observer's Observe
// method with NOTIFY_PREF_CHANGED.
void AddPrefObserver(const char* path, NotificationObserver* obs);
void RemovePrefObserver(const char* path, NotificationObserver* obs);
protected:
// 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.
typedef ObserverList<NotificationObserver> NotificationObserverList;
typedef base::hash_map<std::string, NotificationObserverList*>
PrefObserverMap;
const PrefObserverMap* pref_observers() { return &pref_observers_; }
private:
// Weak references.
PrefService* pref_service_;
PrefValueStore* pref_value_store_;
NotificationRegistrar registrar_;
PrefObserverMap pref_observers_;
// Called after a policy refresh to notify relevant preference observers.
// |changed_prefs_paths| is the vector of preference paths changed by the
// policy update. It is passed by value and not reference because
// this method is called asynchronously as a callback from another thread.
// Copying the vector guarantees that the vector's lifecycle spans the
// method's invocation.
void FireObserversForRefreshedManagedPrefs(
std::vector<std::string> changed_prefs_paths);
// NotificationObserver methods:
virtual void Observe(NotificationType type,
const NotificationSource& source,
const NotificationDetails& details);
DISALLOW_COPY_AND_ASSIGN(PrefNotifier);
};
#endif // CHROME_BROWSER_PREF_NOTIFIER_H_
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