Fix crash in RTP Player on stop and close

When dragging the UI, this somehow causes a great lag. Then by
spam-clicking on the Stop button, a double free seems to occur.

Fix this by moving the audio cleanup to the outputStateChanged callback
as documented at https://doc.qt.io/qt-5/qaudiooutput.html. Note that
calling stop() in the IdleState also triggers a change event, resulting
in the desired cleanup.

Stop streams before the dialog is closed (via accept/reject). This
*cannot* be done in the destrutor of RtpPlayerDialog because destructing
QAudioOutput processes events from the event queue, resulting in
preature destruction of other objects... crash.

Change-Id: I6bfb33c9396e9bc1ffd346519d22390a97b6bdaf
Reviewed-on: https://code.wireshark.org/review/11894
Petri-Dish: Peter Wu <peter@lekensteyn.nl>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Gerald Combs <gerald@wireshark.org>
(cherry picked from commit 0fef9d752f801986a81b7c294143eae21cd0de97)
Reviewed-on: https://code.wireshark.org/review/11930

3 files changed, 28 insertions, 8 deletions

diff --git a/ui/qt/rtp_audio_stream.cpp b/ui/qt/rtp_audio_stream.cpp
index 94149fe3ca..c16eca903c 100644
--- a/ui/qt/rtp_audio_stream.cpp
+++ b/ui/qt/rtp_audio_stream.cpp
@@ -539,10 +539,7 @@ void RtpAudioStream::stopPlaying()
 {
     if (audio_output_) {
         audio_output_->stop();
-        delete audio_output_;
-        audio_output_ = NULL;
     }
-    emit finishedPlaying();
 }
 
 void RtpAudioStream::writeSilence(int samples)
@@ -564,20 +561,23 @@ void RtpAudioStream::writeSilence(int samples)
 
 void RtpAudioStream::outputStateChanged()
 {
-    if (!audio_output_) return;
-
-    if (audio_output_->state() == QAudio::IdleState) {
+    switch (audio_output_->state()) {
+    case QAudio::StoppedState:
         // RTP_STREAM_DEBUG("stopped %f", audio_output_->processedUSecs() / 100000.0);
         delete audio_output_;
         audio_output_ = NULL;
-
         emit finishedPlaying();
+        break;
+    case QAudio::IdleState:
+        audio_output_->stop();
+        break;
+    default:
+        break;
     }
 }
 
 void RtpAudioStream::outputNotify()
 {
-    if (!audio_output_) return;
     emit processedSecs(audio_output_->processedUSecs() / 1000000.0);
 }
 
diff --git a/ui/qt/rtp_player_dialog.cpp b/ui/qt/rtp_player_dialog.cpp
index e5545c99d9..9b26c1fb5a 100644
--- a/ui/qt/rtp_player_dialog.cpp
+++ b/ui/qt/rtp_player_dialog.cpp
@@ -177,6 +177,23 @@ RtpPlayerDialog::~RtpPlayerDialog()
     delete ui;
 }
 
+void RtpPlayerDialog::accept()
+{
+    int row_count = ui->streamTreeWidget->topLevelItemCount();
+    // Stop all streams before the dialogs are closed.
+    for (int row = 0; row < row_count; row++) {
+        QTreeWidgetItem *ti = ui->streamTreeWidget->topLevelItem(row);
+        RtpAudioStream *audio_stream = ti->data(stream_data_col_, Qt::UserRole).value<RtpAudioStream*>();
+        audio_stream->stopPlaying();
+    }
+    WiresharkDialog::accept();
+}
+
+void RtpPlayerDialog::reject()
+{
+    RtpPlayerDialog::accept();
+}
+
 void RtpPlayerDialog::retapPackets()
 {
     register_tap_listener("rtp", this, NULL, 0, NULL, tapPacket, NULL);
diff --git a/ui/qt/rtp_player_dialog.h b/ui/qt/rtp_player_dialog.h
index be3f2c57c1..5f214682da 100644
--- a/ui/qt/rtp_player_dialog.h
+++ b/ui/qt/rtp_player_dialog.h
@@ -61,6 +61,9 @@ public:
 #ifdef QT_MULTIMEDIA_LIB
     ~RtpPlayerDialog();
 
+    void accept();
+    void reject();
+
     /** Add an RTP stream to play.
      * MUST be called before exec().
      * Requires src_addr, src_port, dest_addr, dest_port, ssrc, packet_count,