qqmlabstractprofileradapter.cpp

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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
#include "qqmlabstractprofileradapter_p.h"
 
QT_BEGIN_NAMESPACE
 
/*!
 * \internal
 * \class QQmlAbstractProfilerAdapter
 * \inmodule QtQml
 * Abstract base class for all adapters between profilers and the QQmlProfilerService. Adapters have
 * to retrieve profiler-specific data and convert it to the format sent over the wire. Adapters must
 * live in the QDebugServer thread but the actual profilers can live in different threads. The
 * recommended way to deal with this is passing the profiling data through a signal/slot connection.
 */
 
/*!
 * \internal
 * \fn void QQmlAbstractProfilerAdapter::dataRequested()
 * Signals that data has been requested by the \c QQmlProfilerService. This signal should be
 * connected to a slot in the profiler and the profiler should then transfer its currently available
 * profiling data to the adapter as soon as possible.
 */
 
/*!
 * \internal
 * \fn qint64 QQmlAbstractProfilerAdapter::sendMessages(qint64 until, QList<QByteArray> &messages)
 * Append the messages up to the timestamp \a until, chronologically sorted, to \a messages. Keep
 * track of the messages already sent and with each subsequent call to this method start with the
 * first one not yet sent. Messages that have been sent can be deleted. When new data from the
 * profiler arrives the information about the last sent message must be reset. Return the timestamp
 * of the next message after \a until or \c -1 if there is no such message.
 * The profiler service keeps a list of adapters, sorted by time of next message and keeps querying
 * the first one to send messages up to the time of the second one. Like that we get chronologically
 * sorted messages and can occasionally post the messages to exploit parallelism and save memory.
 */
 
/*!
 * \internal
 * Emits either \c profilingEnabled(quint64) or \c profilingEnabledWhileWaiting(quint64), depending
 * on \c waiting. If the profiler's thread is waiting for an initial start signal, we can emit the
 * signal over a Qt::DirectConnection to avoid the delay of the event loop. The \a features are
 * passed on to the signal.
 */
void QQmlAbstractProfilerAdapter::startProfiling(quint64 features)
{
    if (waiting)
        emit profilingEnabledWhileWaiting(features);
    else
        emit profilingEnabled(features);
    featuresEnabled = features;
    running = true;
}
 
/*!
 * \internal
 * Emits either \c profilingDisabled() or \c profilingDisabledWhileWaiting(), depending on
 * \c waiting. If the profiler's thread is waiting for an initial start signal, we can emit the
 * signal over a Qt::DirectConnection to avoid the delay of the event loop. This should trigger
 * the profiler to report its collected data and subsequently delete it.
 */
void QQmlAbstractProfilerAdapter::stopProfiling() {
    if (waiting)
        emit profilingDisabledWhileWaiting();
    else
        emit profilingDisabled();
    featuresEnabled = 0;
    running = false;
}
 
/*!
 * \internal
 * \fn bool QQmlAbstractProfilerAdapter::isRunning() const
 * Returns if the profiler is currently running. The profiler is considered to be running after
 * \c startProfiling(quint64) has been called until \c stopProfiling() is called. That is
 * independent of \c waiting. The profiler may be running and waiting at the same time.
 */
 
/*!
 * \internal
 * \fn void QQmlAbstractProfilerAdapter::profilingDisabled()
 * This signal is emitted if \c stopProfiling() is called while the profiler is not considered to
 * be waiting. The profiler is expected to handle the signal asynchronously.
 */
 
/*!
 * \internal
 * \fn void QQmlAbstractProfilerAdapter::profilingDisabledWhileWaiting()
 * This signal is emitted if \c stopProfiling() is called while the profiler is considered to be
 * waiting. In many cases this signal can be connected with a Qt::DirectConnection.
 */
 
/*!
 * \internal
 * \fn void QQmlAbstractProfilerAdapter::profilingEnabled(quint64 features)
 * This signal is emitted if \c startProfiling(quint64) is called while the profiler is not
 * considered to be waiting. The profiler is expected to handle the signal asynchronously. The
 * \a features are passed on from \c startProfiling(quint64).
 */
 
/*!
 * \internal
 * \fn void QQmlAbstractProfilerAdapter::profilingEnabledWhileWaiting(quint64 features)
 * This signal is emitted if \c startProfiling(quint64) is called while the profiler is considered
 * to be waiting. In many cases this signal can be connected with a Qt::DirectConnection. By
 * starting the profiler synchronously when the QML engine starts instead of waiting for the first
 * iteration of the event loop the engine startup can be profiled. The \a features are passed on
 * from \c startProfiling(quint64).
 */
 
/*!
 * \internal
 * \fn void QQmlAbstractProfilerAdapter::referenceTimeKnown(const QElapsedTimer &timer)
 * This signal is used to synchronize the profiler's timer to the QQmlProfilerservice's. The
 * profiler is expected to save \a timer and use it for timestamps on its data.
 */
 
/*!
 * \internal
 * \fn void QQmlAbstractProfilerAdapter::synchronize(const QElapsedTimer &timer)
 * Synchronize the profiler to \a timer. This emits \c referenceTimeKnown().
 */
 
/*!
 * \internal
 * \fn void QQmlAbstractProfilerAdapter::reportData()
 * Make the profiler report its current data without stopping the collection. The same (and
 * additional) data can later be requested again with \c stopProfiling() or \c reportData().
 */
 
/*!
 * \internal
 * \fn void QQmlAbstractProfilerAdapter::startWaiting()
 * Consider the profiler to be waiting from now on. While the profiler is waiting it can be directly
 * accessed even if it is in a different thread. This method should only be called if it is actually
 * safe to do so.
 */
 
/*!
 * \internal
 * \fn void QQmlAbstractProfilerAdapter::stopWaiting()
 * Consider the profiler not to be waiting anymore. If it lives in a different threads any requests
 * for it have to be done via a queued connection then.
 */
 
QT_END_NAMESPACE
 
#include "moc_qqmlabstractprofileradapter_p.cpp"