69 lines
2.4 KiB
C++
69 lines
2.4 KiB
C++
|
// Copyright (C) 2025 The Qt Company Ltd.
|
||
|
|
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
|
||
|
|
|
||
|
|
#include "queueworker.h"
|
||
|
|
|
||
|
|
/* view needs 8 items and cacheBuffer of 2 items above and below to show visible area, so limit queue max length to that. */
|
||
|
|
static constexpr int s_queueMaxLength{12};
|
||
|
|
|
||
|
|
QueueWorker::QueueWorker()
|
||
|
|
: QObject{nullptr}
|
||
|
|
{
|
||
|
|
connect(this,
|
||
|
|
&QueueWorker::triggerQueueProcessing,
|
||
|
|
this,
|
||
|
|
&QueueWorker::processQueue,
|
||
|
|
Qt::QueuedConnection);
|
||
|
|
}
|
||
|
|
|
||
|
|
void QueueWorker::abort()
|
||
|
|
{
|
||
|
|
m_killSignalReceived = true;
|
||
|
|
}
|
||
|
|
|
||
|
|
void QueueWorker::fetchData(int id)
|
||
|
|
{
|
||
|
|
if (m_indicesAlreadyFetched.contains(id) || m_indicesToFetch.contains(id)
|
||
|
|
|| m_killSignalReceived)
|
||
|
|
return;
|
||
|
|
|
||
|
|
/* This is signal from UI thread. It is likely that there are more than one in queue.
|
||
|
|
* Add our own triggerQueueProcessing() signal to the end of event queue and add id to queue of IDs.
|
||
|
|
* Then let all queued signals to be processed until QueueWorker receives its own signal.
|
||
|
|
*/
|
||
|
|
sendTriggerQueueProcessingSignal(id);
|
||
|
|
}
|
||
|
|
|
||
|
|
void QueueWorker::processQueue()
|
||
|
|
{
|
||
|
|
/* This slot receives QueueWorker's own signal after all signals from UI thread have been processed. */
|
||
|
|
m_queueProcessingSignalSent = false;
|
||
|
|
const auto index = m_indicesToFetch.dequeue();
|
||
|
|
emit processing(index);
|
||
|
|
const auto data = m_remoteMedia.getElements(1, index);
|
||
|
|
m_indicesAlreadyFetched.insert(index);
|
||
|
|
emit dataFetched(index, data.front());
|
||
|
|
if (!m_indicesToFetch.empty() && !m_killSignalReceived) {
|
||
|
|
/* Queueworker should process more indices, but the UI thread may have sent more signals during previous processing.
|
||
|
|
* Add our own signal to end of event queue and let all preceding signals to be processed before continuing.
|
||
|
|
*/
|
||
|
|
emit triggerQueueProcessing(QPrivateSignal{});
|
||
|
|
m_queueProcessingSignalSent = true;
|
||
|
|
}
|
||
|
|
/* Else all fetches have been processed so far. */
|
||
|
|
}
|
||
|
|
|
||
|
|
void QueueWorker::sendTriggerQueueProcessingSignal(int id)
|
||
|
|
{
|
||
|
|
/* Make sure excess IDs are removed. */
|
||
|
|
while (m_indicesToFetch.size() >= s_queueMaxLength) {
|
||
|
|
emit dropped(m_indicesToFetch.dequeue());
|
||
|
|
}
|
||
|
|
/* Before calling this function QueueWorker has ensured that m_indicesToFetch doesn't contain id yet, so just add id. */
|
||
|
|
m_indicesToFetch.enqueue(id);
|
||
|
|
if (!m_queueProcessingSignalSent) {
|
||
|
|
emit triggerQueueProcessing(QPrivateSignal{});
|
||
|
|
m_queueProcessingSignalSent = true;
|
||
|
|
}
|
||
|
|
}
|