blob: 8a74c750144836489be6482db44cb5e2a1193f98 [file] [log] [blame]
// 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 <map>
#include "base/observer_list.h"
#include "content/common/content_export.h"
#include "content/public/browser/notification_service.h"
namespace content {
class NotificationObserver;
class NotificationRegistrar;
class CONTENT_EXPORT NotificationServiceImpl : public NotificationService {
static NotificationServiceImpl* current();
// Normally instantiated when the thread is created. Not all threads have
// a NotificationService. Only one instance should be created per thread.
~NotificationServiceImpl() override;
// NotificationService:
void Notify(int type,
const NotificationSource& source,
const NotificationDetails& details) override;
friend class NotificationRegistrar;
typedef base::ObserverList<NotificationObserver> NotificationObserverList;
typedef std::map<uintptr_t, NotificationObserverList*> NotificationSourceMap;
typedef std::map<int, NotificationSourceMap> NotificationObserverMap;
typedef std::map<int, int> NotificationObserverCount;
// Convenience function to determine whether a source has a
// NotificationObserverList in the given map;
static bool HasKey(const NotificationSourceMap& map,
const NotificationSource& source);
// NOTE: Rather than using this directly, you should use a
// NotificationRegistrar.
// Registers a NotificationObserver to be called whenever a matching
// notification is posted. Observer is a pointer to an object subclassing
// NotificationObserver to be notified when an event matching the other two
// parameters is posted to this service. Type is the type of events to be
// notified about (or NOTIFICATION_ALL to receive events of all
// types).
// Source is a NotificationSource object (created using
// "Source<classname>(pointer)"), if this observer only wants to
// receive events from that object, or NotificationService::AllSources()
// to receive events from all sources.
// A given observer can be registered only once for each combination of
// type and source. If the same object is registered more than once,
// it must be removed for each of those combinations of type and source later.
// The caller retains ownership of the object pointed to by observer.
void AddObserver(NotificationObserver* observer,
int type,
const NotificationSource& source);
// NOTE: Rather than using this directly, you should use a
// NotificationRegistrar.
// Removes the object pointed to by observer from receiving notifications
// that match type and source. If no object matching the parameters is
// currently registered, this method is a no-op.
void RemoveObserver(NotificationObserver* observer,
int type,
const NotificationSource& source);
// Keeps track of the observers for each type of notification.
// Until we get a prohibitively large number of notification types,
// a simple array is probably the fastest way to dispatch.
NotificationObserverMap observers_;
#ifndef NDEBUG
// Used to check to see that AddObserver and RemoveObserver calls are
// balanced.
NotificationObserverCount observer_counts_;
} // namespace content