Improvement for the preloading system: Now it is possible to abort running Preloader instances. This helps greatly with the Live Mode, when items are reshuffled before playing.

Took a bit longer than expected, since it was more complicated to implement than I had originally thought. On the upside, I've learned more tricks about GStreamer, which is a good thing (tm).

Fixes #2087

campcaster/src/modules/gstreamerElements/src/minimal-audio-smil.c

@@ -51,6 +51,13 @@
 
 /* ===================================================  local data structures */
 
+
+enum {
+    ARG_0,
+    ARG_ABORT
+};
+
+
 /**
  *  ElementFactory information
  */
@@ -89,6 +96,7 @@ static GstStaticPadTemplate src_factory = GST_STATIC_PAD_TEMPLATE (
                                             "rate = (int) [ 8000, 96000 ]"));
 
 
+
 /* ================================================  local constants & macros */
 
 #define NSEC_PER_SEC_FLOAT  1000000000.0
@@ -122,6 +130,10 @@ GST_PLUGIN_DEFINE(GST_VERSION_MAJOR,
 
 /* ===============================================  local function prototypes */
 
+static void
+livesupport_minimal_audio_smil_set_property( GObject * object, guint prop_id, const GValue * value, GParamSpec * pspec );
+
+
 /**
  *  Read the sink stream into memory, using a oneshotreader element.
  *
@@ -272,6 +284,29 @@ livesupport_minimal_audio_smil_class_init(
 
 /* =============================================================  module code */
 
+static void
+livesupport_minimal_audio_smil_set_property( GObject * object, guint prop_id, const GValue * value, GParamSpec * pspec )
+{
+    LivesupportMinimalAudioSmil* smil;
+
+    /* it's not null if we got it, but it might not be ours */
+    g_return_if_fail(LIVESUPPORT_IS_MINIMAL_AUDIO_SMIL(object));
+
+    smil = LIVESUPPORT_MINIMAL_AUDIO_SMIL(object);
+
+    switch ( prop_id )
+    {
+        case ARG_ABORT:
+            smil->myclass->abort = g_value_get_pointer (value);
+            printf("SETTING ABORT POINTER: %d\n", smil->myclass->abort);
+            break;
+
+        default:
+            G_OBJECT_WARN_INVALID_PROPERTY_ID ( object, prop_id, pspec );
+            break;
+    }
+}
+
 /*------------------------------------------------------------------------------
  *  Read the sink stream into memory, using a oneshotreader element.
  *----------------------------------------------------------------------------*/
@@ -351,7 +386,7 @@ handle_animate_element(LivesupportMinimalAudioSmil  * smil,
 
     /* handle the attributes */
     for (attr = ((xmlElement*)animate)->attributes;
-         attr;
+         attr && !(*smil->myclass->abort);
          attr = (xmlAttribute*) attr->next) {
 
         xmlNode * node;
@@ -509,7 +544,7 @@ handle_audio_element(LivesupportMinimalAudioSmil  * smil,
 
     /* handle the attributes */
     for (attr = ((xmlElement*)audio)->attributes;
-         attr;
+         attr && !(*smil->myclass->abort);
          attr = (xmlAttribute*) attr->next) {
 
         xmlNode * node;
@@ -584,7 +619,7 @@ handle_audio_element(LivesupportMinimalAudioSmil  * smil,
 
     /* now handle the possible animate elements inside this audio element */
     element = pplay;
-    for (ix = 0, node = audio->children; node; node = node->next, ++ix) {
+    for (ix = 0, node = audio->children; node && !(*smil->myclass->abort); node = node->next, ++ix) {
         if (node->type == XML_ELEMENT_NODE) {
             GstElement    * elem = 0;
 
@@ -658,7 +693,7 @@ handle_par_element(LivesupportMinimalAudioSmil    * smil,
     g_value_unset(&gvalue);
 
 
-    for (index = 0, node = par->children; node; node = node->next, ++index) {
+    for (index = 0, node = par->children; node && !(*smil->myclass->abort); node = node->next, ++index) {
         if (node->type == XML_ELEMENT_NODE) {
             GstElement    * element = 0;
 
@@ -731,7 +766,7 @@ process_smil_file(LivesupportMinimalAudioSmil * smil)
         return FALSE;
     }
 
-    for (node = node->children; node; node = node->next) {
+    for (node = node->children; node && !(*smil->myclass->abort); node = node->next) {
         if (node->type == XML_ELEMENT_NODE) {
             GstElement    * element = 0;
 
@@ -838,6 +873,10 @@ livesupport_minimal_audio_smil_dispose(GObject * object)
 static void
 livesupport_minimal_audio_smil_init(LivesupportMinimalAudioSmil * smil)
 {
+    printf("INIT().\n");
+
+    smil->myclass = (LivesupportMinimalAudioSmilClass*) G_OBJECT_GET_CLASS(smil);
+
     GValue      gvalue = { 0 };
     GstPad    * oneshotReaderSink;
 
@@ -913,6 +952,8 @@ static void
 livesupport_minimal_audio_smil_class_init(
                                     LivesupportMinimalAudioSmilClass  * klass)
 {
+    printf("CLASS_INIT().\n");
+
     GObjectClass      * gobject_class;
     GstElementClass   * gstelement_class;
 
@@ -920,9 +961,13 @@ livesupport_minimal_audio_smil_class_init(
     gstelement_class = (GstElementClass *) klass;
     parent_class     = (GstBinClass*)g_type_class_ref(GST_TYPE_BIN);
 
+    g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_ABORT, g_param_spec_pointer
+                                    ("abort", "abort", "abort", (GParamFlags)G_PARAM_WRITABLE));
+
     gobject_class->dispose         = livesupport_minimal_audio_smil_dispose;
-    gstelement_class->change_state =
+    gobject_class->set_property    = livesupport_minimal_audio_smil_set_property;
-                                    livesupport_minimal_audio_smil_change_state;
+    gstelement_class->change_state = livesupport_minimal_audio_smil_change_state;
+
 
     /* check for the libxml version */
     LIBXML_TEST_VERSION

campcaster/src/modules/gstreamerElements/src/minimal-audio-smil.h

@@ -80,6 +80,7 @@ typedef struct _LivesupportMinimalAudioSmilClass
  *  The MinimalAudioSmil object structure.
  */
 struct _LivesupportMinimalAudioSmil {
+    LivesupportMinimalAudioSmilClass* myclass;
     GstBin          parent;
 
     GstPad        * sinkpad;
@@ -99,6 +100,8 @@ struct _LivesupportMinimalAudioSmil {
  */
 struct _LivesupportMinimalAudioSmilClass {
     GstBinClass     parent_class;
+
+    gboolean*       abort;
 };
 
 

campcaster/src/modules/playlistExecutor/src/GstreamerPlayer.cxx

@@ -644,6 +644,8 @@ Preloader::Preloader(GstreamerPlayer* player, const std::string url) throw()
     , m_fileUrl(url)
 {
     DEBUG_FUNC_INFO
+
+    player->m_stopPreloader = false;
 }
 
 
@@ -688,6 +690,7 @@ void Preloader::run() throw()
     gst_element_set(p->m_preloadFilesrc, "location", filePath.c_str(), NULL);
 
     p->m_preloadDecoder = gst_element_factory_make("minimalaudiosmil", NULL);
+    gst_element_set(p->m_preloadDecoder, "abort", &p->m_stopPreloader, NULL);
 
     GstElement* pipe     = gst_pipeline_new("pipe");
     GstElement* fakesink = gst_element_factory_make("fakesink", "fakesink");
@@ -697,13 +700,20 @@ void Preloader::run() throw()
     gst_element_set_state(pipe, GST_STATE_PLAYING);
 
     gint64 position = 0LL;
-    while (position == 0LL && gst_bin_iterate(GST_BIN(pipe))) {
+    while (position == 0LL && !p->m_stopPreloader && gst_bin_iterate(GST_BIN(pipe))) {
         GstFormat   format = GST_FORMAT_DEFAULT;
         gst_element_query(fakesink, GST_QUERY_POSITION, &format, &position);
     }
 
     gst_element_set_state(pipe, GST_STATE_PAUSED);
 
+    if (p->m_stopPreloader) {
+        debug() << "Aborting preloader, per request." << endl;
+        g_object_unref(G_OBJECT(p->m_preloadFilesrc));
+        g_object_unref(G_OBJECT(p->m_preloadDecoder));
+        return;
+    }
+
     g_object_ref(G_OBJECT(p->m_preloadFilesrc));
     g_object_ref(G_OBJECT(p->m_preloadDecoder));
     gst_bin_remove_many(GST_BIN(pipe), p->m_preloadFilesrc, p->m_preloadDecoder, NULL);
@@ -720,8 +730,11 @@ void Preloader::signal(int) throw()
 {}
 
 
-// TODO This should be implemented by adding a "abort" property to the minimalaudiosmil element.
 void Preloader::stop() throw()
-{}
+{
+    DEBUG_FUNC_INFO
+
+    m_player->m_stopPreloader = true;
+}
 
 

campcaster/src/modules/playlistExecutor/src/GstreamerPlayer.h

@@ -170,6 +170,12 @@ class GstreamerPlayer : virtual public Configurable,
          */
         Ptr<Thread>::Ref        m_preloadThread;
 
+        /**
+         *  Flag that indicates that the preloader should abort.  
+         */
+
+        gboolean                m_stopPreloader;
+
         /**
          *  The type for the vector of listeners.
          *  Just a shorthand notation, to make reference to the type