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// 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.
#ifndef CONTENT_PUBLIC_BROWSER_NOTIFICATION_REGISTRAR_H_
#define CONTENT_PUBLIC_BROWSER_NOTIFICATION_REGISTRAR_H_
#include <vector>
#include "base/basictypes.h"
#include "base/threading/non_thread_safe.h"
#include "content/common/content_export.h"
namespace content {
class NotificationObserver;
class NotificationSource;
// Aids in registering for notifications and ensures that all registered
// notifications are unregistered when the class is destroyed.
//
// The intended use is that you make a NotificationRegistrar member in your
// class and use it to register your notifications instead of going through the
// notification service directly. It will automatically unregister them for
// you.
class CONTENT_EXPORT NotificationRegistrar :
NON_EXPORTED_BASE(public base::NonThreadSafe) {
public:
// This class must not be derived from (we don't have a virtual destructor so
// it won't work). Instead, use it as a member in your class.
NotificationRegistrar();
~NotificationRegistrar();
// Wrappers around NotificationService::[Add|Remove]Observer.
void Add(NotificationObserver* observer,
int type,
const NotificationSource& source);
void Remove(NotificationObserver* observer,
int type,
const NotificationSource& source);
// Unregisters all notifications.
void RemoveAll();
// Returns true if no notifications are registered.
bool IsEmpty() const;
// Returns true if there is already a registered notification with the
// specified details.
bool IsRegistered(NotificationObserver* observer,
int type,
const NotificationSource& source);
private:
struct Record;
// We keep registered notifications in a simple vector. This means we'll do
// brute-force searches when removing them individually, but individual
// removal is uncommon, and there will typically only be a couple of
// notifications anyway.
typedef std::vector<Record> RecordVector;
// Lists all notifications we're currently registered for.
RecordVector registered_;
DISALLOW_COPY_AND_ASSIGN(NotificationRegistrar);
};
} // namespace content
#endif // CONTENT_PUBLIC_BROWSER_NOTIFICATION_REGISTRAR_H_
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