ladspa: comment signalprocessor class more and do minor code cleanups

ext/ladspa/gstsignalprocessor.c

@@ -21,6 +21,21 @@
  * Boston, MA 02111-1307, USA.
  */
 
+/*
+ * SECTION:gstsignalprocessor
+ *
+ * This baseclass allows to write elements that need data on all pads before
+ * their processing function can run.
+ *
+ * In push mode (gst_signal_processor_chain) it operates as follows:
+ * 1. store each received buffer on the pad and decrement pending_in
+ * 2. when pending_in==0, process as much as we can and push outputs
+ *
+ * In pull mode (gst_signal_processor_getrange) is operates as follows:
+ * 1. if there is an output ready, deliver
+ * 2. otherwise pull from each sink-pad, process requested frames and deliver
+ *    the buffer
+ */
 
 #include <stdlib.h>
 
@@ -71,26 +86,33 @@ gst_signal_processor_pad_template_get_type (void)
   return type;
 }
 
-/* FIXME: better allow the caller to pass on the template, right now this can
+/*
- * only create mono pads */
+ * gst_signal_processor_class_add_pad_template:
+ * @klass: element class
+ * @name: pad name
+ * @direction: pad direction (src/sink)
+ * @index: index for the pad per direction (starting from 0)
+ *
+ */
 void
 gst_signal_processor_class_add_pad_template (GstSignalProcessorClass * klass,
     const gchar * name, GstPadDirection direction, guint index)
 {
   GstPadTemplate *new;
+  GstCaps *caps;
 
   g_return_if_fail (GST_IS_SIGNAL_PROCESSOR_CLASS (klass));
   g_return_if_fail (name != NULL);
   g_return_if_fail (direction == GST_PAD_SRC || direction == GST_PAD_SINK);
 
-  new = g_object_new (gst_signal_processor_pad_template_get_type (),
+  /* FIXME: would be nice to have the template as a parameter, right now this can
-      "name", name, NULL);
+   * only create mono pads */
+  caps = gst_caps_copy (gst_static_caps_get (&template_caps));
+
+  new = g_object_new (gst_signal_processor_pad_template_get_type (),
+      "name", name, "name-template", name,
+      "direction", direction, "presence", GST_PAD_ALWAYS, "caps", caps, NULL);
 
-  GST_PAD_TEMPLATE_NAME_TEMPLATE (new) = g_strdup (name);
-  GST_PAD_TEMPLATE_DIRECTION (new) = direction;
-  GST_PAD_TEMPLATE_PRESENCE (new) = GST_PAD_ALWAYS;
-  GST_PAD_TEMPLATE_CAPS (new) = gst_caps_copy (gst_static_caps_get
-      (&template_caps));
   GST_SIGNAL_PROCESSOR_PAD_TEMPLATE (new)->index = index;
 
   gst_element_class_add_pad_template (GST_ELEMENT_CLASS (klass), new);
@@ -110,11 +132,12 @@ struct _GstSignalProcessorPad
 
   GstBuffer *pen;
 
+  /* index for the pad per direction (starting from 0) */
   guint index;
 
   /* these are only used for sink pads */
-  guint samples_avail;
+  guint samples_avail;          /* available mono sample frames */
-  gfloat *data;
+  gfloat *data;                 /* data pointer to read from / write to */
 };
 
 static GType
@@ -140,10 +163,6 @@ GST_BOILERPLATE (GstSignalProcessor, gst_signal_processor, GstElement,
 
 
 static void gst_signal_processor_finalize (GObject * object);
-static void gst_signal_processor_set_property (GObject * object, guint prop_id,
-    const GValue * value, GParamSpec * pspec);
-static void gst_signal_processor_get_property (GObject * object, guint prop_id,
-    GValue * value, GParamSpec * pspec);
 static gboolean gst_signal_processor_src_activate_pull (GstPad * pad,
     gboolean active);
 static gboolean gst_signal_processor_sink_activate_push (GstPad * pad,
@@ -176,10 +195,6 @@ gst_signal_processor_class_init (GstSignalProcessorClass * klass)
   gstelement_class = GST_ELEMENT_CLASS (klass);
 
   gobject_class->finalize = GST_DEBUG_FUNCPTR (gst_signal_processor_finalize);
-  gobject_class->set_property =
-      GST_DEBUG_FUNCPTR (gst_signal_processor_set_property);
-  gobject_class->get_property =
-      GST_DEBUG_FUNCPTR (gst_signal_processor_get_property);
 
   gstelement_class->change_state =
       GST_DEBUG_FUNCPTR (gst_signal_processor_change_state);
@@ -345,7 +360,7 @@ gst_signal_processor_stop (GstSignalProcessor * self)
     klass->stop (self);
 
   for (sinks = elem->sinkpads; sinks; sinks = sinks->next)
-    /* force set_caps when going to RUNNING, see note in set_caps */
+    /* force set_caps when going to RUNNING, see note in _setcaps () */
     gst_pad_set_caps (GST_PAD (sinks->data), NULL);
 
   /* should also flush our buffers perhaps? */
@@ -449,7 +464,7 @@ gst_signal_processor_setcaps (GstPad * pad, GstCaps * caps)
       gst_signal_processor_cleanup (self);
 
     if (!gst_signal_processor_setup (self, sample_rate))
-      goto start_failed;
+      goto start_or_setup_failed;
 
     self->sample_rate = sample_rate;
     gst_caps_replace (&self->caps, caps);
@@ -464,16 +479,16 @@ gst_signal_processor_setcaps (GstPad * pad, GstCaps * caps)
      when we leave that the processor is RUNNING. */
   if (!GST_SIGNAL_PROCESSOR_IS_INITIALIZED (self)
       && !gst_signal_processor_setup (self, self->sample_rate))
-    goto start_failed;
+    goto start_or_setup_failed;
   if (!GST_SIGNAL_PROCESSOR_IS_RUNNING (self)
       && !gst_signal_processor_start (self))
-    goto start_failed;
+    goto start_or_setup_failed;
 
   gst_object_unref (self);
 
   return TRUE;
 
-start_failed:
+start_or_setup_failed:
   {
     gst_object_unref (self);
     return FALSE;
@@ -501,8 +516,8 @@ gst_signal_processor_event (GstPad * pad, GstEvent * event)
   self = GST_SIGNAL_PROCESSOR (gst_pad_get_parent (pad));
   bclass = GST_SIGNAL_PROCESSOR_GET_CLASS (self);
 
-  /* FIXME, this probably isn't the correct interface: what about return values, what
+  /* FIXME, this probably isn't the correct interface: what about return values,
-   * about overriding event_default
+   * what about overriding event_default
    * Sync with GstBaseTransform::gst_base_transform_sink_event */
   if (bclass->event)
     bclass->event (self, event);
@@ -545,6 +560,8 @@ gst_signal_processor_prepare (GstSignalProcessor * self, guint nframes)
     self->audio_in[sinkpad->index] = sinkpad->data;
   }
 
+  /* FIXME: return if samples_avail==0 ? */
+
   /* now assign output buffers. we can avoid allocation by reusing input
      buffers, but only if process() can work in place, and if the input buffer
      is the exact size of the number of samples we are processing. */
@@ -637,11 +654,13 @@ gst_signal_processor_process (GstSignalProcessor * self, guint nframes)
   GstElement *elem;
   GstSignalProcessorClass *klass;
 
+  /* check if we have buffers enqueued */
   g_return_if_fail (self->pending_in == 0);
   g_return_if_fail (self->pending_out == 0);
 
   elem = GST_ELEMENT (self);
 
+  /* check how much input is available and prepare output buffers */
   nframes = gst_signal_processor_prepare (self, nframes);
   if (G_UNLIKELY (nframes == 0))
     goto flow_error;
@@ -704,6 +723,7 @@ gst_signal_processor_flush (GstSignalProcessor * self)
 
   GST_INFO_OBJECT (self, "flush()");
 
+  /* release enqueued buffers */
   for (pads = GST_ELEMENT (self)->pads; pads; pads = pads->next) {
     GstSignalProcessorPad *spad = (GstSignalProcessorPad *) pads->data;
 
@@ -715,6 +735,7 @@ gst_signal_processor_flush (GstSignalProcessor * self)
     }
   }
 
+  /* no outputs prepared and inputs for each pad needed */
   self->pending_out = 0;
   self->pending_in = klass->num_audio_in;
 }
@@ -863,32 +884,6 @@ gst_signal_processor_chain (GstPad * pad, GstBuffer * buffer)
   return self->flow_state;
 }
 
-static void
-gst_signal_processor_set_property (GObject * object, guint prop_id,
-    const GValue * value, GParamSpec * pspec)
-{
-  /* GstSignalProcessor *self = GST_SIGNAL_PROCESSOR (object); */
-
-  switch (prop_id) {
-    default:
-      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
-      break;
-  }
-}
-
-static void
-gst_signal_processor_get_property (GObject * object, guint prop_id,
-    GValue * value, GParamSpec * pspec)
-{
-  /* GstSignalProcessor *self = GST_SIGNAL_PROCESSOR (object); */
-
-  switch (prop_id) {
-    default:
-      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
-      break;
-  }
-}
-
 static gboolean
 gst_signal_processor_sink_activate_push (GstPad * pad, gboolean active)
 {

ext/ladspa/gstsignalprocessor.h

@@ -79,7 +79,9 @@ struct _GstSignalProcessor {
 
   GstActivateMode mode;
 
+  /* pending inputs before processing can take place */
   guint pending_in;
+  /* panding outputs to be filled */
   guint pending_out;
 
   gfloat *control_in;