1 // Copyright 2013 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef UI_MESSAGE_CENTER_NOTIFICATION_BLOCKER_H_ 6 #define UI_MESSAGE_CENTER_NOTIFICATION_BLOCKER_H_ 7 8 #include "base/observer_list.h" 9 #include "ui/message_center/message_center_export.h" 10 #include "ui/message_center/notification.h" 11 12 namespace message_center { 13 class MessageCenter; 14 15 // NotificationBlocker manages the availability of notifications based on the 16 // current system status. Each NotificationBlocker implementation covers a 17 // single state such as screen lock or fullscreen. 18 class MESSAGE_CENTER_EXPORT NotificationBlocker { 19 public: 20 class Observer { 21 public: 22 virtual void OnBlockingStateChanged(NotificationBlocker* blocker) = 0; 23 }; 24 25 explicit NotificationBlocker(MessageCenter* message_center); 26 virtual ~NotificationBlocker(); 27 28 void AddObserver(Observer* observer); 29 void RemoveObserver(Observer* observer); 30 31 // Checks the current state and updates the availability. CheckState()32 virtual void CheckState() {} 33 34 // Returns true when notifications from |notifier_id| should appear in the 35 // message center. Default returns true always. 36 virtual bool ShouldShowNotification(const NotifierId& notifier_id) const; 37 38 // Returns true when notifications from |notifier_id| should be shown as 39 // popups on screen. If it's false, those notifications should be queued. 40 // When a blocker starts returning false for a notification which is already 41 // shown as a popup, the notification should be closed as a popup immediately. 42 virtual bool ShouldShowNotificationAsPopup( 43 const NotifierId& notifier_id) const = 0; 44 45 protected: message_center()46 MessageCenter* message_center() { return message_center_; } 47 void NotifyBlockingStateChanged(); 48 49 private: 50 ObserverList<Observer> observers_; 51 MessageCenter* message_center_; // weak 52 }; 53 54 typedef std::vector<NotificationBlocker*> NotificationBlockers; 55 56 } // namespace message_center 57 58 #endif // UI_MESSAGE_CENTER_NOTIFICATION_BLOCKER_H_ 59