chromium/ui/message_center/notification_blocker.h

// Copyright 2013 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef UI_MESSAGE_CENTER_NOTIFICATION_BLOCKER_H_
#define UI_MESSAGE_CENTER_NOTIFICATION_BLOCKER_H_

#include "base/memory/raw_ptr.h"
#include "base/observer_list.h"
#include "base/observer_list_types.h"
#include "ui/message_center/message_center_export.h"
#include "ui/message_center/public/cpp/notification.h"

namespace message_center {
class MessageCenter;

// NotificationBlocker manages the availability of notifications based on the
// current system status. Each NotificationBlocker implementation covers a
// single state such as screen lock or fullscreen.
//
// The current notification state is automatically updated when a blocker is
// initialized or destroyed. For instance, the `WelcomeTourNotificationBlocker`
// blocks all existing notifications when it is initialized (see below for how
// to properly initialize a `NotificationBlocker` subclass), and unblocks
// notifications when it is destructed.
//
// An object of a class that derives from this is not ready until `Init()` has
// been called. The following example demonstrates how to properly initialize
// such an object:
//
//   class MyNotificationBlocker : public NotificationBlocker {
//    public:
//     MyNotificationBlocker(MessageCenter* message_center, ...)
//         : NotificationBlocker(message_center), ... { ... }
//    ...
//   };
//
//   void foo() {
//     MessageCenter* message_center = ...;
//     std::unique_ptr<MyNotificationBlocker> my_blocker =
//         std::make_unique<MyNotificationBlocker>(message_center, ...);
//     my_blocker->Init();  /* DON'T FORGET THIS LINE! */
//     ...
//   }
//
// TODO(b/290637034): Improve upon the `Init()` pattern as it is easy to forget
// to call `Init()` when initializing a `NotificationBlocker` subclass.
class MESSAGE_CENTER_EXPORT NotificationBlocker { … };

NotificationBlockers;

}  // namespace message_center

#endif  // UI_MESSAGE_CENTER_NOTIFICATION_BLOCKER_H_