146 строки
4.9 KiB
C++
146 строки
4.9 KiB
C++
//
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// TimedNotificationQueue.h
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//
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// $Id: //poco/1.4/Foundation/include/Poco/TimedNotificationQueue.h#2 $
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//
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// Library: Foundation
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// Package: Notifications
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// Module: TimedNotificationQueue
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//
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// Definition of the TimedNotificationQueue class.
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//
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// Copyright (c) 2009, Applied Informatics Software Engineering GmbH.
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// and Contributors.
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//
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// SPDX-License-Identifier: BSL-1.0
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//
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#ifndef Foundation_TimedNotificationQueue_INCLUDED
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#define Foundation_TimedNotificationQueue_INCLUDED
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#include "Poco/Foundation.h"
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#include "Poco/Notification.h"
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#include "Poco/Mutex.h"
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#include "Poco/Event.h"
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#include "Poco/Timestamp.h"
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#include "Poco/Clock.h"
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#include <map>
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namespace Poco {
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class Foundation_API TimedNotificationQueue
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/// A TimedNotificationQueue object provides a way to implement timed, asynchronous
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/// notifications. This is especially useful for sending notifications
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/// from one thread to another, for example from a background thread to
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/// the main (user interface) thread.
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///
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/// The TimedNotificationQueue is quite similar to the NotificationQueue class.
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/// The only difference to NotificationQueue is that each Notification is tagged
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/// with a Timestamp. When inserting a Notification into the queue, the
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/// Notification is inserted according to the given Timestamp, with
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/// lower Timestamp values being inserted before higher ones.
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///
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/// Notifications are dequeued in order of their timestamps.
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///
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/// TimedNotificationQueue has some restrictions regarding multithreaded use.
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/// While multiple threads may enqueue notifications, only one thread at a
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/// time may dequeue notifications from the queue.
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///
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/// If two threads try to dequeue a notification simultaneously, the results
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/// are undefined.
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{
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public:
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TimedNotificationQueue();
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/// Creates the TimedNotificationQueue.
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~TimedNotificationQueue();
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/// Destroys the TimedNotificationQueue.
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void enqueueNotification(Notification::Ptr pNotification, Timestamp timestamp);
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/// Enqueues the given notification by adding it to
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/// the queue according to the given timestamp.
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/// Lower timestamp values are inserted before higher ones.
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/// The queue takes ownership of the notification, thus
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/// a call like
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/// notificationQueue.enqueueNotification(new MyNotification, someTime);
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/// does not result in a memory leak.
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///
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/// The Timestamp is converted to an equivalent Clock value.
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void enqueueNotification(Notification::Ptr pNotification, Clock clock);
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/// Enqueues the given notification by adding it to
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/// the queue according to the given clock value.
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/// Lower clock values are inserted before higher ones.
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/// The queue takes ownership of the notification, thus
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/// a call like
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/// notificationQueue.enqueueNotification(new MyNotification, someTime);
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/// does not result in a memory leak.
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Notification* dequeueNotification();
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/// Dequeues the next pending notification with a timestamp
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/// less than or equal to the current time.
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/// Returns 0 (null) if no notification is available.
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/// The caller gains ownership of the notification and
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/// is expected to release it when done with it.
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///
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/// It is highly recommended that the result is immediately
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/// assigned to a Notification::Ptr, to avoid potential
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/// memory management issues.
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Notification* waitDequeueNotification();
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/// Dequeues the next pending notification.
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/// If no notification is available, waits for a notification
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/// to be enqueued.
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/// The caller gains ownership of the notification and
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/// is expected to release it when done with it.
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///
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/// It is highly recommended that the result is immediately
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/// assigned to a Notification::Ptr, to avoid potential
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/// memory management issues.
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Notification* waitDequeueNotification(long milliseconds);
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/// Dequeues the next pending notification.
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/// If no notification is available, waits for a notification
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/// to be enqueued up to the specified time.
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/// Returns 0 (null) if no notification is available.
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/// The caller gains ownership of the notification and
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/// is expected to release it when done with it.
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///
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/// It is highly recommended that the result is immediately
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/// assigned to a Notification::Ptr, to avoid potential
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/// memory management issues.
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bool empty() const;
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/// Returns true iff the queue is empty.
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int size() const;
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/// Returns the number of notifications in the queue.
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void clear();
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/// Removes all notifications from the queue.
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///
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/// Calling clear() while another thread executes one of
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/// the dequeue member functions will result in undefined
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/// behavior.
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protected:
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typedef std::multimap<Clock, Notification::Ptr> NfQueue;
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Notification::Ptr dequeueOne(NfQueue::iterator& it);
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bool wait(Clock::ClockDiff interval);
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private:
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NfQueue _nfQueue;
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Event _nfAvailable;
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mutable FastMutex _mutex;
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};
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} // namespace Poco
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#endif // Foundation_TimedNotificationQueue_INCLUDED
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