Fix a crash in the gstreamer audio output

Closing the audio output would delete the pipeline, and would
lead to deleting the GstAppSrc from within QGstAppSrc::pushData().

Speed up the qsoundeffect autotest (this uncovered the issue).

Change-Id: I3c5843854f5a74d563eb271df553c8a1a5854f63
Reviewed-by: André de la Rocha <andre.rocha@qt.io>
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

2 files changed, 37 insertions, 26 deletions

diff --git a/src/multimedia/platform/gstreamer/audio/qaudiooutput_gstreamer.cpp b/src/multimedia/platform/gstreamer/audio/qaudiooutput_gstreamer.cpp
index eb74c2ee6..1b0fec46a 100644
--- a/src/multimedia/platform/gstreamer/audio/qaudiooutput_gstreamer.cpp
+++ b/src/multimedia/platform/gstreamer/audio/qaudiooutput_gstreamer.cpp
@@ -61,14 +61,35 @@ QGStreamerAudioOutput::QGStreamerAudioOutput(const QAudioDeviceInfo &device)
 {
     gstPipeline.installMessageFilter(this);
 
+    m_appSrc = new QGstAppSrc;
+    connect(m_appSrc, &QGstAppSrc::bytesProcessed, this, &QGStreamerAudioOutput::bytesProcessedByAppSrc);
+    connect(m_appSrc, &QGstAppSrc::noMoreData, this, &QGStreamerAudioOutput::needData);
+    gstAppSrc = m_appSrc->element();
+
+    //    gstDecodeBin = gst_element_factory_make ("decodebin", "dec");
+    QGstElement conv("audioconvert", "conv");
+    gstVolume = QGstElement("volume", "volume");
+    if (m_volume != 1.)
+        gstVolume.set("volume", m_volume);
+
+    // link decodeBin to audioconvert in a callback once we get a pad from the decoder
+    //    g_signal_connect (gstDecodeBin, "pad-added", (GCallback) padAdded, conv);
+
     const auto *audioInfo = static_cast<const QGStreamerAudioDeviceInfo *>(device.handle());
     gstOutput = gst_device_create_element(audioInfo->gstDevice, nullptr);
+
+    gstPipeline.add(gstAppSrc, /*gstDecodeBin, */ conv, gstVolume, gstOutput);
+    gstAppSrc.link(conv, gstVolume, gstOutput);
 }
 
 QGStreamerAudioOutput::~QGStreamerAudioOutput()
 {
     close();
-    QCoreApplication::processEvents();
+    gstPipeline = {};
+    gstVolume = {};
+    gstAppSrc = {};
+    delete m_appSrc;
+    m_appSrc = nullptr;
 }
 
 void QGStreamerAudioOutput::setError(QAudio::Error error)
@@ -203,26 +224,9 @@ bool QGStreamerAudioOutput::open()
     }
 
 //    qDebug() << "GST caps:" << gst_caps_to_string(caps);
-    m_appSrc = new QGstAppSrc;
     m_appSrc->setup(m_audioSource, m_audioSource ? m_audioSource->pos() : 0);
     m_appSrc->setAudioFormat(m_format);
 
-    connect(m_appSrc, &QGstAppSrc::bytesProcessed, this, &QGStreamerAudioOutput::bytesProcessedByAppSrc);
-    connect(m_appSrc, &QGstAppSrc::noMoreData, this, &QGStreamerAudioOutput::needData);
-    gstAppSrc = m_appSrc->element();
-
-//    gstDecodeBin = gst_element_factory_make ("decodebin", "dec");
-    QGstElement conv("audioconvert", "conv");
-    gstVolume = QGstElement("volume", "volume");
-    if (m_volume != 1.)
-        gstVolume.set("volume", m_volume);
-
-    gstPipeline.add(gstAppSrc, /*gstDecodeBin, */ conv, gstVolume, gstOutput);
-    gstAppSrc.link(conv, gstVolume, gstOutput);
-
-    // link decodeBin to audioconvert in a callback once we get a pad from the decoder
-//    g_signal_connect (gstDecodeBin, "pad-added", (GCallback) padAdded, conv);
-
     /* run */
     gstPipeline.setState(GST_STATE_PLAYING);
 
@@ -239,10 +243,8 @@ void QGStreamerAudioOutput::close()
     if (!m_opened)
         return;
 
-    gstPipeline.setStateSync(GST_STATE_NULL);
-    gstPipeline = {};
-    gstVolume = {};
-    gstAppSrc = {};
+    if (!gstPipeline.setStateSync(GST_STATE_NULL))
+        qWarning() << "failed to close the audio output stream";
 
     if (!m_pullMode && m_audioSource)
         delete m_audioSource;
diff --git a/src/multimedia/platform/gstreamer/common/qgstappsrc.cpp b/src/multimedia/platform/gstreamer/common/qgstappsrc.cpp
index 7ff9b177f..2cf33fbce 100644
--- a/src/multimedia/platform/gstreamer/common/qgstappsrc.cpp
+++ b/src/multimedia/platform/gstreamer/common/qgstappsrc.cpp
@@ -56,6 +56,9 @@ QGstAppSrc::QGstAppSrc(QObject *parent)
 
 QGstAppSrc::~QGstAppSrc()
 {
+    m_appSrc.setStateSync(GST_STATE_NULL);
+    streamDestroyed();
+    qCDebug(qLcAppSrc) << "~QGstAppSrc";
 }
 
 bool QGstAppSrc::setup(QIODevice *stream, qint64 offset)
@@ -68,6 +71,7 @@ bool QGstAppSrc::setup(QIODevice *stream, qint64 offset)
 
     auto *appSrc = GST_APP_SRC(m_appSrc.element());
     GstAppSrcCallbacks m_callbacks;
+    memset(&m_callbacks, 0, sizeof(GstAppSrcCallbacks));
     m_callbacks.need_data   = &QGstAppSrc::on_need_data;
     m_callbacks.enough_data = &QGstAppSrc::on_enough_data;
     m_callbacks.seek_data   = &QGstAppSrc::on_seek_data;
@@ -141,20 +145,20 @@ void QGstAppSrc::write(const char *data, qsizetype size)
     Q_ASSERT(!m_stream);
     m_buffer.append(data, size);
     m_noMoreData = false;
-    if (m_dataRequestSize)
-        pushData();
+    pushData();
 }
 
 void QGstAppSrc::onDataReady()
 {
     qCDebug(qLcAppSrc) << "onDataReady" << m_stream->bytesAvailable() << m_stream->size();
-    if (m_dataRequestSize)
-        pushData();
+    pushData();
 }
 
 void QGstAppSrc::streamDestroyed()
 {
+    qCDebug(qLcAppSrc) << "stream destroyed";
     m_stream = nullptr;
+    m_dataRequestSize = 0;
     sendEOS();
 }
 
@@ -166,6 +170,7 @@ void QGstAppSrc::pushData()
     qCDebug(qLcAppSrc) << "pushData" << m_stream << m_stream->atEnd() << m_buffer.size();
     if ((m_stream && m_stream->atEnd())) {
         eosOrIdle();
+        qCDebug(qLcAppSrc) << "end pushData" << m_stream << m_stream->atEnd() << m_buffer.size();
         return;
     }
 
@@ -213,6 +218,7 @@ void QGstAppSrc::pushData()
     if (bytesRead == 0) {
         gst_buffer_unref(buffer);
         eosOrIdle();
+        qCDebug(qLcAppSrc) << "end pushData" << m_stream << m_stream->atEnd() << m_buffer.size();
         return;
     }
     m_noMoreData = false;
@@ -224,6 +230,8 @@ void QGstAppSrc::pushData()
     } else if (ret == GST_FLOW_FLUSHING) {
         qWarning() << "QGstAppSrc: push buffer wrong state";
     }
+    qCDebug(qLcAppSrc) << "end pushData" << m_stream << m_stream->atEnd() << m_buffer.size();
+
 }
 
 bool QGstAppSrc::doSeek(qint64 value)
@@ -264,6 +272,7 @@ void QGstAppSrc::on_need_data(GstAppSrc *, guint arg0, gpointer userdata)
     Q_ASSERT(self);
     self->m_dataRequestSize = arg0;
     QMetaObject::invokeMethod(self, "pushData", Qt::AutoConnection);
+    qCDebug(qLcAppSrc) << "done on_need_data";
 }
 
 void QGstAppSrc::sendEOS()