mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-12-04 21:42:39 +00:00
161 lines
5.2 KiB
C++
161 lines
5.2 KiB
C++
|
//
|
||
|
// PriorityNotificationQueue.h
|
||
|
//
|
||
|
// $Id: //poco/1.4/Foundation/include/Poco/PriorityNotificationQueue.h#1 $
|
||
|
//
|
||
|
// Library: Foundation
|
||
|
// Package: Notifications
|
||
|
// Module: PriorityNotificationQueue
|
||
|
//
|
||
|
// Definition of the PriorityNotificationQueue class.
|
||
|
//
|
||
|
// Copyright (c) 2009, Applied Informatics Software Engineering GmbH.
|
||
|
// and Contributors.
|
||
|
//
|
||
|
// SPDX-License-Identifier: BSL-1.0
|
||
|
//
|
||
|
|
||
|
|
||
|
#ifndef Foundation_PriorityNotificationQueue_INCLUDED
|
||
|
#define Foundation_PriorityNotificationQueue_INCLUDED
|
||
|
|
||
|
|
||
|
#include "Poco/Foundation.h"
|
||
|
#include "Poco/Notification.h"
|
||
|
#include "Poco/Mutex.h"
|
||
|
#include "Poco/Event.h"
|
||
|
#include <map>
|
||
|
#include <deque>
|
||
|
|
||
|
|
||
|
namespace Poco {
|
||
|
|
||
|
|
||
|
class NotificationCenter;
|
||
|
|
||
|
|
||
|
class Foundation_API PriorityNotificationQueue
|
||
|
/// A PriorityNotificationQueue object provides a way to implement asynchronous
|
||
|
/// notifications. This is especially useful for sending notifications
|
||
|
/// from one thread to another, for example from a background thread to
|
||
|
/// the main (user interface) thread.
|
||
|
///
|
||
|
/// The PriorityNotificationQueue is quite similar to the NotificationQueue class.
|
||
|
/// The only difference to NotificationQueue is that each Notification is tagged
|
||
|
/// with a priority value. When inserting a Notification into the queue, the
|
||
|
/// Notification is inserted according to the given priority value, with
|
||
|
/// lower priority values being inserted before higher priority
|
||
|
/// values. Therefore, the lower the numerical priority value, the higher
|
||
|
/// the actual notification priority.
|
||
|
///
|
||
|
/// Notifications are dequeued in order of their priority.
|
||
|
///
|
||
|
/// The PriorityNotificationQueue can also be used to distribute work from
|
||
|
/// a controlling thread to one or more worker threads. Each worker thread
|
||
|
/// repeatedly calls waitDequeueNotification() and processes the
|
||
|
/// returned notification. Special care must be taken when shutting
|
||
|
/// down a queue with worker threads waiting for notifications.
|
||
|
/// The recommended sequence to shut down and destroy the queue is to
|
||
|
/// 1. set a termination flag for every worker thread
|
||
|
/// 2. call the wakeUpAll() method
|
||
|
/// 3. join each worker thread
|
||
|
/// 4. destroy the notification queue.
|
||
|
{
|
||
|
public:
|
||
|
PriorityNotificationQueue();
|
||
|
/// Creates the PriorityNotificationQueue.
|
||
|
|
||
|
~PriorityNotificationQueue();
|
||
|
/// Destroys the PriorityNotificationQueue.
|
||
|
|
||
|
void enqueueNotification(Notification::Ptr pNotification, int priority);
|
||
|
/// Enqueues the given notification by adding it to
|
||
|
/// the queue according to the given priority.
|
||
|
/// Lower priority values are inserted before higher priority values.
|
||
|
/// The queue takes ownership of the notification, thus
|
||
|
/// a call like
|
||
|
/// notificationQueue.enqueueNotification(new MyNotification, 1);
|
||
|
/// does not result in a memory leak.
|
||
|
|
||
|
Notification* dequeueNotification();
|
||
|
/// Dequeues the next pending notification.
|
||
|
/// Returns 0 (null) if no notification is available.
|
||
|
/// The caller gains ownership of the notification and
|
||
|
/// is expected to release it when done with it.
|
||
|
///
|
||
|
/// It is highly recommended that the result is immediately
|
||
|
/// assigned to a Notification::Ptr, to avoid potential
|
||
|
/// memory management issues.
|
||
|
|
||
|
Notification* waitDequeueNotification();
|
||
|
/// Dequeues the next pending notification.
|
||
|
/// If no notification is available, waits for a notification
|
||
|
/// to be enqueued.
|
||
|
/// The caller gains ownership of the notification and
|
||
|
/// is expected to release it when done with it.
|
||
|
/// This method returns 0 (null) if wakeUpAll()
|
||
|
/// has been called by another thread.
|
||
|
///
|
||
|
/// It is highly recommended that the result is immediately
|
||
|
/// assigned to a Notification::Ptr, to avoid potential
|
||
|
/// memory management issues.
|
||
|
|
||
|
Notification* waitDequeueNotification(long milliseconds);
|
||
|
/// Dequeues the next pending notification.
|
||
|
/// If no notification is available, waits for a notification
|
||
|
/// to be enqueued up to the specified time.
|
||
|
/// Returns 0 (null) if no notification is available.
|
||
|
/// The caller gains ownership of the notification and
|
||
|
/// is expected to release it when done with it.
|
||
|
///
|
||
|
/// It is highly recommended that the result is immediately
|
||
|
/// assigned to a Notification::Ptr, to avoid potential
|
||
|
/// memory management issues.
|
||
|
|
||
|
void dispatch(NotificationCenter& notificationCenter);
|
||
|
/// Dispatches all queued notifications to the given
|
||
|
/// notification center.
|
||
|
|
||
|
void wakeUpAll();
|
||
|
/// Wakes up all threads that wait for a notification.
|
||
|
|
||
|
bool empty() const;
|
||
|
/// Returns true iff the queue is empty.
|
||
|
|
||
|
int size() const;
|
||
|
/// Returns the number of notifications in the queue.
|
||
|
|
||
|
void clear();
|
||
|
/// Removes all notifications from the queue.
|
||
|
|
||
|
bool hasIdleThreads() const;
|
||
|
/// Returns true if the queue has at least one thread waiting
|
||
|
/// for a notification.
|
||
|
|
||
|
static PriorityNotificationQueue& defaultQueue();
|
||
|
/// Returns a reference to the default
|
||
|
/// PriorityNotificationQueue.
|
||
|
|
||
|
protected:
|
||
|
Notification::Ptr dequeueOne();
|
||
|
|
||
|
private:
|
||
|
typedef std::multimap<int, Notification::Ptr> NfQueue;
|
||
|
struct WaitInfo
|
||
|
{
|
||
|
Notification::Ptr pNf;
|
||
|
Event nfAvailable;
|
||
|
};
|
||
|
typedef std::deque<WaitInfo*> WaitQueue;
|
||
|
|
||
|
NfQueue _nfQueue;
|
||
|
WaitQueue _waitQueue;
|
||
|
mutable FastMutex _mutex;
|
||
|
};
|
||
|
|
||
|
|
||
|
} // namespace Poco
|
||
|
|
||
|
|
||
|
#endif // Foundation_PriorityNotificationQueue_INCLUDED
|