inputselector: Block when receiving an EOS event on a deactivated pad

... and only unblock when either a) the pad becomes active and the event
should be forwarded or b) the active pad went EOS itself.

Otherwise it can happen that we switch from a longer track that is not EOS yet
to a shorter track that already is EOS, but the shorter track won't have any
possibility to send its EOS event downstream anymore.

https://bugzilla.gnome.org/show_bug.cgi?id=740949

plugins/elements/gstinputselector.c

@@ -434,6 +434,17 @@ gst_selector_pad_iterate_linked_pads (GstPad * pad, GstObject * parent)
   return it;
 }
 
+static gboolean
+gst_input_selector_eos_wait (GstInputSelector * self, GstSelectorPad * pad)
+{
+  while (!self->eos && !self->flushing && !pad->flushing) {
+    /* we can be unlocked here when we are shutting down (flushing) or when we
+     * get unblocked */
+    GST_INPUT_SELECTOR_WAIT (self);
+  }
+  return self->flushing;
+}
+
 static gboolean
 gst_selector_pad_event (GstPad * pad, GstObject * parent, GstEvent * event)
 {
@@ -483,6 +494,7 @@ gst_selector_pad_event (GstPad * pad, GstObject * parent, GstEvent * event)
     case GST_EVENT_FLUSH_START:
       /* Unblock the pad if it's waiting */
       selpad->flushing = TRUE;
+      sel->eos = FALSE;
       GST_INPUT_SELECTOR_BROADCAST (sel);
       break;
     case GST_EVENT_FLUSH_STOP:
@@ -520,21 +532,12 @@ gst_selector_pad_event (GstPad * pad, GstObject * parent, GstEvent * event)
     case GST_EVENT_EOS:
       selpad->eos = TRUE;
 
-      if (forward) {
-        selpad->eos_sent = TRUE;
-      } else {
-        GstSelectorPad *active_selpad;
-
-        /* If the active sinkpad is in EOS state but EOS
-         * was not sent downstream this means that the pad
-         * got EOS before it was set as active pad and that
-         * the previously active pad got EOS after it was
-         * active
-         */
-        active_selpad = GST_SELECTOR_PAD (active_sinkpad);
-        forward = (active_selpad->eos && !active_selpad->eos_sent);
-        active_selpad->eos_sent = TRUE;
+      if (!forward) {
+        /* blocked until active the sind pad or flush */
+        gst_input_selector_eos_wait (sel, selpad);
+        forward = TRUE;
       }
+      selpad->eos_sent = TRUE;
       GST_DEBUG_OBJECT (pad, "received EOS");
       break;
     case GST_EVENT_GAP:{
@@ -692,6 +695,12 @@ gst_input_selector_wait_running_time (GstInputSelector * sel,
         gst_input_selector_activate_sinkpad (sel, GST_PAD_CAST (selpad));
     active_selpad = GST_SELECTOR_PAD_CAST (active_sinkpad);
 
+    if (sel->eos) {
+      GST_DEBUG_OBJECT (sel, "Not waiting because inputselector reach EOS.");
+      GST_INPUT_SELECTOR_UNLOCK (sel);
+      return FALSE;
+    }
+
     if (seg->format != GST_FORMAT_TIME) {
       GST_DEBUG_OBJECT (selpad,
           "Not waiting because we don't have a TIME segment");
@@ -961,6 +970,12 @@ gst_selector_pad_chain (GstPad * pad, GstObject * parent, GstBuffer * buf)
       GST_TIME_ARGS (GST_BUFFER_PTS (buf)));
 
   GST_INPUT_SELECTOR_LOCK (sel);
+  if (sel->eos) {
+    GST_DEBUG_OBJECT (pad, "inputselector eos.");
+    GST_INPUT_SELECTOR_UNLOCK (sel);
+    goto eos;
+  }
+
   /* wait or check for flushing */
   if (gst_input_selector_wait (sel, selpad)) {
     GST_INPUT_SELECTOR_UNLOCK (sel);
@@ -1143,6 +1158,13 @@ flushing:
     res = GST_FLOW_FLUSHING;
     goto done;
   }
+eos:
+  {
+    GST_DEBUG_OBJECT (pad, "We are eos, discard buffer %p", buf);
+    gst_buffer_unref (buf);
+    res = GST_FLOW_EOS;
+    goto done;
+  }
 }
 
 static void gst_input_selector_dispose (GObject * object);
@@ -1302,6 +1324,7 @@ gst_input_selector_init (GstInputSelector * sel)
   g_mutex_init (&sel->lock);
   g_cond_init (&sel->cond);
   sel->blocked = FALSE;
+  sel->eos = FALSE;
 
   /* lets give a change for downstream to do something on
    * active-pad change before we start pushing new buffers */
@@ -1370,6 +1393,11 @@ gst_input_selector_set_active_pad (GstInputSelector * self, GstPad * pad)
   GST_DEBUG_OBJECT (self, "New active pad is %" GST_PTR_FORMAT,
       self->active_sinkpad);
 
+  if (old != new && new->eos && !new->eos_sent) {
+    self->eos = TRUE;
+    GST_INPUT_SELECTOR_BROADCAST (self);
+  }
+
   return TRUE;
 }
 
@@ -1764,6 +1792,7 @@ gst_input_selector_change_state (GstElement * element,
   switch (transition) {
     case GST_STATE_CHANGE_READY_TO_PAUSED:
       GST_INPUT_SELECTOR_LOCK (self);
+      self->eos = FALSE;
       self->blocked = FALSE;
       self->flushing = FALSE;
       GST_INPUT_SELECTOR_UNLOCK (self);
@@ -1772,6 +1801,7 @@ gst_input_selector_change_state (GstElement * element,
       /* first unlock before we call the parent state change function, which
        * tries to acquire the stream lock when going to ready. */
       GST_INPUT_SELECTOR_LOCK (self);
+      self->eos = TRUE;
       self->blocked = FALSE;
       self->flushing = TRUE;
       GST_INPUT_SELECTOR_BROADCAST (self);

plugins/elements/gstinputselector.h

@@ -77,6 +77,7 @@ struct _GstInputSelector {
   GMutex lock;
   GCond cond;
   gboolean blocked;
+  gboolean eos;
   gboolean flushing;
 };