pitch: fix multithread accesses

- fully protect accesses to the libsoundtouch API that is not
  thread-safe.
- fully protect accesses to GstPitch members that could be read by a
  downstream query thread while written by an upstream streaming thread
  or a user thread.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/6247>

subprojects/gst-plugins-bad/ext/soundtouch/gstpitch.cc

@@ -98,6 +98,7 @@ GST_STATIC_PAD_TEMPLATE ("src",
     GST_STATIC_CAPS (SUPPORTED_CAPS));
 
 static void gst_pitch_dispose (GObject * object);
+static void gst_pitch_finalize (GObject * object);
 static void gst_pitch_set_property (GObject * object,
     guint prop_id, const GValue * value, GParamSpec * pspec);
 static void gst_pitch_get_property (GObject * object,
@@ -136,6 +137,7 @@ gst_pitch_class_init (GstPitchClass * klass)
   gobject_class->set_property = gst_pitch_set_property;
   gobject_class->get_property = gst_pitch_get_property;
   gobject_class->dispose = GST_DEBUG_FUNCPTR (gst_pitch_dispose);
+  gobject_class->finalize = GST_DEBUG_FUNCPTR (gst_pitch_finalize);
 
   g_object_class_install_property (gobject_class, ARG_PITCH,
       g_param_spec_float ("pitch", "Pitch",
@@ -223,12 +225,23 @@ gst_pitch_dispose (GObject * object)
   GstPitch *pitch = GST_PITCH (object);
   GstPitchPrivate *priv = GST_PITCH_GET_PRIVATE (pitch);
 
+  gst_clear_event (&priv->pending_segment);
+
+  G_OBJECT_CLASS (parent_class)->dispose (object);
+}
+
+static void
+gst_pitch_finalize (GObject * object)
+{
+  GstPitch *pitch = GST_PITCH (object);
+  GstPitchPrivate *priv = GST_PITCH_GET_PRIVATE (pitch);
+
   if (priv->st) {
     delete priv->st;
     priv->st = NULL;
   }
 
-  G_OBJECT_CLASS (parent_class)->dispose (object);
+  G_OBJECT_CLASS (parent_class)->finalize (object);
 }
 
 static void
@@ -247,9 +260,9 @@ gst_pitch_set_property (GObject * object, guint prop_id,
   GstPitch *pitch = GST_PITCH (object);
   GstPitchPrivate *priv = GST_PITCH_GET_PRIVATE (pitch);
 
-  GST_OBJECT_LOCK (pitch);
   switch (prop_id) {
     case ARG_TEMPO:
+      GST_OBJECT_LOCK (pitch);
       pitch->tempo = g_value_get_float (value);
       priv->stream_time_ratio =
           pitch->tempo * pitch->rate * pitch->segment_applied_rate;
@@ -258,6 +271,7 @@ gst_pitch_set_property (GObject * object, guint prop_id,
       gst_pitch_update_duration (pitch);
       break;
     case ARG_RATE:
+      GST_OBJECT_LOCK (pitch);
       pitch->rate = g_value_get_float (value);
       priv->stream_time_ratio =
           pitch->tempo * pitch->rate * pitch->segment_applied_rate;
@@ -267,17 +281,18 @@ gst_pitch_set_property (GObject * object, guint prop_id,
       break;
     case ARG_OUTPUT_RATE:
       /* Has no effect until the next input segment */
+      GST_OBJECT_LOCK (pitch);
       pitch->output_rate = g_value_get_float (value);
       GST_OBJECT_UNLOCK (pitch);
       break;
     case ARG_PITCH:
+      GST_OBJECT_LOCK (pitch);
       pitch->pitch = g_value_get_float (value);
       priv->st->setPitch (pitch->pitch);
       GST_OBJECT_UNLOCK (pitch);
       break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
-      GST_OBJECT_UNLOCK (pitch);
       break;
   }
 }
@@ -288,43 +303,47 @@ gst_pitch_get_property (GObject * object, guint prop_id,
 {
   GstPitch *pitch = GST_PITCH (object);
 
-  GST_OBJECT_LOCK (pitch);
   switch (prop_id) {
     case ARG_TEMPO:
+      GST_OBJECT_LOCK (pitch);
       g_value_set_float (value, pitch->tempo);
+      GST_OBJECT_UNLOCK (pitch);
       break;
     case ARG_RATE:
+      GST_OBJECT_LOCK (pitch);
       g_value_set_float (value, pitch->rate);
+      GST_OBJECT_UNLOCK (pitch);
       break;
     case ARG_OUTPUT_RATE:
+      GST_OBJECT_LOCK (pitch);
       g_value_set_float (value, pitch->output_rate);
+      GST_OBJECT_UNLOCK (pitch);
       break;
     case ARG_PITCH:
+      GST_OBJECT_LOCK (pitch);
       g_value_set_float (value, pitch->pitch);
+      GST_OBJECT_UNLOCK (pitch);
       break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
       break;
   }
-  GST_OBJECT_UNLOCK (pitch);
 }
 
 static gboolean
 gst_pitch_setcaps (GstPitch * pitch, GstCaps * caps)
 {
-  GstPitchPrivate *priv;
+  GstAudioInfo info;
-
+  if (!gst_audio_info_from_caps (&info, caps))
-  priv = GST_PITCH_GET_PRIVATE (pitch);
-
-  if (!gst_audio_info_from_caps (&pitch->info, caps))
     return FALSE;
 
   GST_OBJECT_LOCK (pitch);
+  pitch->info = info;
 
   /* notify the soundtouch instance of this change */
+  GstPitchPrivate *priv = GST_PITCH_GET_PRIVATE (pitch);
   priv->st->setSampleRate (pitch->info.rate);
   priv->st->setChannels (pitch->info.channels);
-
   GST_OBJECT_UNLOCK (pitch);
 
   return TRUE;
@@ -336,6 +355,8 @@ gst_pitch_forward_buffer (GstPitch * pitch, GstBuffer * buffer)
 {
   gint samples;
 
+  GST_OBJECT_LOCK (pitch);
+
   GST_BUFFER_TIMESTAMP (buffer) = pitch->next_buffer_time;
   pitch->next_buffer_time += GST_BUFFER_DURATION (buffer);
 
@@ -348,6 +369,8 @@ gst_pitch_forward_buffer (GstPitch * pitch, GstBuffer * buffer)
       "] (%d samples)", GST_TIME_ARGS (GST_BUFFER_TIMESTAMP (buffer)),
       GST_TIME_ARGS (pitch->next_buffer_time), samples);
 
+  GST_OBJECT_UNLOCK (pitch);
+
   return gst_pad_push (pitch->srcpad, buffer);
 }
 
@@ -355,35 +378,36 @@ gst_pitch_forward_buffer (GstPitch * pitch, GstBuffer * buffer)
 static GstBuffer *
 gst_pitch_prepare_buffer (GstPitch * pitch)
 {
-  GstPitchPrivate *priv;
+  GstBuffer *buffer = NULL;
-  guint samples;
-  GstBuffer *buffer;
-  GstMapInfo info;
-
-  priv = GST_PITCH_GET_PRIVATE (pitch);
-
   GST_LOG_OBJECT (pitch, "preparing buffer");
 
-  samples = priv->st->numSamples ();
+  GST_OBJECT_LOCK (pitch);
-  if (samples == 0)
-    return NULL;
 
+  GstPitchPrivate *priv = GST_PITCH_GET_PRIVATE (pitch);
+  guint samples = priv->st->numSamples ();
+  if (samples > 0) {
     buffer = gst_buffer_new_and_alloc (samples * pitch->info.bpf);
 
+    GstMapInfo info;
     gst_buffer_map (buffer, &info, (GstMapFlags) GST_MAP_READWRITE);
+
     samples =
-      priv->st->receiveSamples ((soundtouch::SAMPLETYPE *) info.data, samples);
+        priv->st->receiveSamples ((soundtouch::SAMPLETYPE *) info.data,
+        samples);
     gst_buffer_unmap (buffer, &info);
 
-  if (samples <= 0) {
+    if (samples > 0) {
-    gst_buffer_unref (buffer);
-    return NULL;
-  }
-
       GST_BUFFER_DURATION (buffer) =
           gst_util_uint64_scale (samples, GST_SECOND, pitch->info.rate);
       /* temporary store samples here, to avoid having to recalculate this */
       GST_BUFFER_OFFSET (buffer) = (gint64) samples;
+    } else {
+      gst_buffer_unref (buffer);
+      buffer = NULL;
+    }
+  }
+
+  GST_OBJECT_UNLOCK (pitch);
 
   return buffer;
 }
@@ -397,10 +421,12 @@ gst_pitch_flush_buffer (GstPitch * pitch, gboolean send)
   GstBuffer *buffer;
   GstPitchPrivate *priv = GST_PITCH_GET_PRIVATE (pitch);
 
+  GST_OBJECT_LOCK (pitch);
   if (priv->st->numUnprocessedSamples () != 0) {
-    GST_DEBUG_OBJECT (pitch, "flushing buffer");
+    GST_DEBUG_OBJECT (pitch, "flushing SoundTouch buffer");
     priv->st->flush ();
   }
+  GST_OBJECT_UNLOCK (pitch);
 
   if (!send)
     return GST_FLOW_OK;
@@ -560,6 +586,7 @@ gst_pitch_src_query (GstPad * pad, GstObject * parent, GstQuery * query)
   gfloat stream_time_ratio;
   gint64 next_buffer_offset;
   GstClockTime next_buffer_time;
+  GstClockTimeDiff min_latency, max_latency;
 
   pitch = GST_PITCH (parent);
   GstPitchPrivate *priv = GST_PITCH_GET_PRIVATE (pitch);
@@ -570,6 +597,8 @@ gst_pitch_src_query (GstPad * pad, GstObject * parent, GstQuery * query)
   stream_time_ratio = priv->stream_time_ratio;
   next_buffer_time = pitch->next_buffer_time;
   next_buffer_offset = pitch->next_buffer_offset;
+  min_latency = pitch->min_latency;
+  max_latency = pitch->max_latency;
   GST_OBJECT_UNLOCK (pitch);
 
   switch (GST_QUERY_TYPE (query)) {
@@ -654,12 +683,11 @@ gst_pitch_src_query (GstPad * pad, GstObject * parent, GstQuery * query)
 
           GST_DEBUG ("Our latency: min %" GST_TIME_FORMAT
               ", max %" GST_TIME_FORMAT,
-              GST_TIME_ARGS (pitch->min_latency),
+              GST_TIME_ARGS (min_latency), GST_TIME_ARGS (max_latency));
-              GST_TIME_ARGS (pitch->max_latency));
 
-          min += pitch->min_latency;
+          min += min_latency;
           if (max != GST_CLOCK_TIME_NONE)
-            max += pitch->max_latency;
+            max += max_latency;
 
           GST_DEBUG ("Calculated total latency : min %"
               GST_TIME_FORMAT " max %" GST_TIME_FORMAT,
@@ -693,6 +721,7 @@ gst_pitch_process_segment (GstPitch * pitch, GstEvent ** event)
   GstSegment seg;
 
   g_return_val_if_fail (event, FALSE);
+  g_return_val_if_fail (*event, FALSE);
 
   GstPitchPrivate *priv = GST_PITCH_GET_PRIVATE (pitch);
 
@@ -765,26 +794,37 @@ gst_pitch_sink_event (GstPad * pad, GstObject * parent, GstEvent * event)
   switch (GST_EVENT_TYPE (event)) {
     case GST_EVENT_FLUSH_STOP:
       gst_pitch_flush_buffer (pitch, FALSE);
+      GST_OBJECT_LOCK (pitch);
       priv->st->clear ();
       pitch->next_buffer_offset = 0;
       pitch->next_buffer_time = GST_CLOCK_TIME_NONE;
       pitch->min_latency = pitch->max_latency = 0;
+      GST_OBJECT_UNLOCK (pitch);
       break;
     case GST_EVENT_EOS:
       gst_pitch_flush_buffer (pitch, TRUE);
+      GST_OBJECT_LOCK (pitch);
       priv->st->clear ();
       pitch->min_latency = pitch->max_latency = 0;
+      GST_OBJECT_UNLOCK (pitch);
       break;
     case GST_EVENT_SEGMENT:
       if (!gst_pitch_process_segment (pitch, &event)) {
         GST_LOG_OBJECT (pad, "not enough data known, stalling segment");
-        if (GST_PITCH_GET_PRIVATE (pitch)->pending_segment)
+
-          gst_event_unref (GST_PITCH_GET_PRIVATE (pitch)->pending_segment);
+        GST_OBJECT_LOCK (pitch);
-        GST_PITCH_GET_PRIVATE (pitch)->pending_segment = event;
+        if (priv->pending_segment)
+          gst_event_unref (priv->pending_segment);
+        priv->pending_segment = event;
+        GST_OBJECT_UNLOCK (pitch);
+
         event = NULL;
       }
+
+      GST_OBJECT_LOCK (pitch);
       priv->st->clear ();
       pitch->min_latency = pitch->max_latency = 0;
+      GST_OBJECT_UNLOCK (pitch);
       break;
     case GST_EVENT_CAPS:
     {
@@ -814,7 +854,9 @@ gst_pitch_update_latency (GstPitch * pitch, GstClockTime timestamp)
 {
   GstClockTimeDiff current_latency, min_latency, max_latency;
   GstPitchPrivate *priv = GST_PITCH_GET_PRIVATE (pitch);
+  gboolean post_new_latency_message = FALSE;
 
+  GST_OBJECT_LOCK (pitch);
   current_latency =
       (GstClockTimeDiff) (timestamp / priv->stream_time_ratio) -
       pitch->next_buffer_time;
@@ -825,12 +867,15 @@ gst_pitch_update_latency (GstPitch * pitch, GstClockTime timestamp)
   if (pitch->min_latency != min_latency || pitch->max_latency != max_latency) {
     pitch->min_latency = min_latency;
     pitch->max_latency = max_latency;
+    post_new_latency_message = TRUE;
+  }
+  GST_OBJECT_UNLOCK (pitch);
 
+  if (post_new_latency_message) {
     /* FIXME: what about the LATENCY event? It only has
      * one latency value, should it be current, min or max?
      * Should it include upstream latencies?
      */
-
     gst_element_post_message (GST_ELEMENT (pitch),
         gst_message_new_latency (GST_OBJECT (pitch)));
   }
@@ -839,74 +884,72 @@ gst_pitch_update_latency (GstPitch * pitch, GstClockTime timestamp)
 static GstFlowReturn
 gst_pitch_chain (GstPad * pad, GstObject * parent, GstBuffer * buffer)
 {
-  GstPitch *pitch;
+  GstPitch *pitch = GST_PITCH (parent);
-  GstPitchPrivate *priv;
+  GstPitchPrivate *priv = GST_PITCH_GET_PRIVATE (pitch);
-  GstClockTime timestamp;
-  GstMapInfo info;
 
-  pitch = GST_PITCH (parent);
+  GstClockTime timestamp = GST_BUFFER_TIMESTAMP (buffer);
-  priv = GST_PITCH_GET_PRIVATE (pitch);
-
-  timestamp = GST_BUFFER_TIMESTAMP (buffer);
-
-  // Remember the first time and corresponding offset
-  if (!GST_CLOCK_TIME_IS_VALID (pitch->next_buffer_time)) {
-    gfloat stream_time_ratio;
-    GstFormat out_format = GST_FORMAT_DEFAULT;
 
   GST_OBJECT_LOCK (pitch);
-    stream_time_ratio = priv->stream_time_ratio;
+  GstClockTime next_buffer_time = pitch->next_buffer_time;
+  gfloat stream_time_ratio = priv->stream_time_ratio;
+  gint bytes_per_frame = pitch->info.bpf;
+  GstEvent *pending_segment = priv->pending_segment;
+  priv->pending_segment = NULL;
   GST_OBJECT_UNLOCK (pitch);
 
-    pitch->next_buffer_time = timestamp / stream_time_ratio;
+  // Remember the first time and corresponding offset
+  if (!GST_CLOCK_TIME_IS_VALID (next_buffer_time)) {
+    GstFormat out_format = GST_FORMAT_DEFAULT;
+    gint64 next_buffer_offset;
+
+    next_buffer_time = timestamp / stream_time_ratio;
     gst_pitch_convert (pitch, GST_FORMAT_TIME, timestamp, &out_format,
-        &pitch->next_buffer_offset);
+        &next_buffer_offset);
+
+    GST_OBJECT_LOCK (pitch);
+    pitch->next_buffer_time = next_buffer_time;
+    pitch->next_buffer_offset = next_buffer_offset;
+    GST_OBJECT_UNLOCK (pitch);
   }
 
-  gst_object_sync_values (GST_OBJECT (pitch), pitch->next_buffer_time);
+  gst_object_sync_values (GST_OBJECT (pitch), next_buffer_time);
 
   /* push the received samples on the soundtouch buffer */
   GST_LOG_OBJECT (pitch, "incoming buffer (%d samples) %" GST_TIME_FORMAT,
-      (gint) (gst_buffer_get_size (buffer) / pitch->info.bpf),
+      (gint) (gst_buffer_get_size (buffer) / bytes_per_frame),
       GST_TIME_ARGS (timestamp));
 
-  if (GST_PITCH_GET_PRIVATE (pitch)->pending_segment) {
+  if (pending_segment) {
-    GstEvent *event =
-        gst_event_copy (GST_PITCH_GET_PRIVATE (pitch)->pending_segment);
-
     GST_LOG_OBJECT (pitch, "processing stalled segment");
-    if (!gst_pitch_process_segment (pitch, &event)) {
+
+    if (!gst_pitch_process_segment (pitch, &pending_segment)) {
       gst_buffer_unref (buffer);
-      gst_event_unref (event);
+      gst_event_unref (pending_segment);
       return GST_FLOW_ERROR;
     }
 
-    if (!gst_pad_event_default (pitch->sinkpad, parent, event)) {
+    if (!gst_pad_event_default (pitch->sinkpad, parent, pending_segment)) {
       gst_buffer_unref (buffer);
-      gst_event_unref (event);
       return GST_FLOW_ERROR;
     }
-
-    gst_event_unref (GST_PITCH_GET_PRIVATE (pitch)->pending_segment);
-    GST_PITCH_GET_PRIVATE (pitch)->pending_segment = NULL;
   }
 
+  GstMapInfo info;
   gst_buffer_map (buffer, &info, GST_MAP_READ);
   GST_OBJECT_LOCK (pitch);
   priv->st->putSamples ((soundtouch::SAMPLETYPE *) info.data,
-      info.size / pitch->info.bpf);
+      info.size / bytes_per_frame);
+  gboolean has_output_samples_available = !priv->st->isEmpty ();
   GST_OBJECT_UNLOCK (pitch);
   gst_buffer_unmap (buffer, &info);
   gst_buffer_unref (buffer);
 
   /* Calculate latency */
-
   gst_pitch_update_latency (pitch, timestamp);
-  /* and try to extract some samples from the soundtouch buffer */
-  if (!priv->st->isEmpty ()) {
-    GstBuffer *out_buffer;
 
-    out_buffer = gst_pitch_prepare_buffer (pitch);
+  /* and try to extract some samples from the soundtouch buffer */
+  if (has_output_samples_available) {
+    GstBuffer *out_buffer = gst_pitch_prepare_buffer (pitch);
     if (out_buffer)
       return gst_pitch_forward_buffer (pitch, out_buffer);
   }
@@ -922,15 +965,13 @@ gst_pitch_change_state (GstElement * element, GstStateChange transition)
   GstPitchPrivate *priv = GST_PITCH_GET_PRIVATE (pitch);
 
   switch (transition) {
-    case GST_STATE_CHANGE_NULL_TO_READY:
-      break;
     case GST_STATE_CHANGE_READY_TO_PAUSED:
+      GST_OBJECT_LOCK (pitch);
       pitch->next_buffer_time = GST_CLOCK_TIME_NONE;
       pitch->next_buffer_offset = 0;
       priv->st->clear ();
       pitch->min_latency = pitch->max_latency = 0;
-      break;
+      GST_OBJECT_UNLOCK (pitch);
-    case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
       break;
     default:
       break;
@@ -941,15 +982,14 @@ gst_pitch_change_state (GstElement * element, GstStateChange transition)
     return ret;
 
   switch (transition) {
-    case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
-      break;
     case GST_STATE_CHANGE_PAUSED_TO_READY:
-      if (GST_PITCH_GET_PRIVATE (pitch)->pending_segment) {
+      GST_OBJECT_LOCK (pitch);
-        gst_event_unref (GST_PITCH_GET_PRIVATE (pitch)->pending_segment);
+      if (priv->pending_segment) {
-        GST_PITCH_GET_PRIVATE (pitch)->pending_segment = NULL;
+        gst_event_unref (priv->pending_segment);
+        priv->pending_segment = NULL;
       }
+      GST_OBJECT_UNLOCK (pitch);
       break;
-    case GST_STATE_CHANGE_READY_TO_NULL:
     default:
       break;
   }