ext/alsa/: Don't open the device if we're a mixer (= padless).

Original commit message from CVS:
* ext/alsa/gstalsa.c: (gst_alsa_get_property),
(gst_alsa_open_audio), (gst_alsa_close_audio):
* ext/alsa/gstalsa.c:
Don't open the device if we're a mixer (= padless).
* ext/alsa/gstalsamixer.c: (gst_alsa_mixer_class_init),
(gst_alsa_mixer_init), (gst_alsa_mixer_open),
(gst_alsa_mixer_close), (gst_alsa_mixer_change_state):
Open mixer during state change rather than during object
initialization. Also, get a device name. Currently in a somewhat
hackish fashion, but I didn't really find something better.

ChangeLog

@@ -1,3 +1,16 @@
+2004-03-15  Ronald Bultje  <rbultje@ronald.bitfreak.net>
+
+	* ext/alsa/gstalsa.c: (gst_alsa_get_property),
+	(gst_alsa_open_audio), (gst_alsa_close_audio):
+	* ext/alsa/gstalsa.c:
+	  Don't open the device if we're a mixer (= padless).
+	* ext/alsa/gstalsamixer.c: (gst_alsa_mixer_class_init),
+	(gst_alsa_mixer_init), (gst_alsa_mixer_open),
+	(gst_alsa_mixer_close), (gst_alsa_mixer_change_state):
+	  Open mixer during state change rather than during object
+	  initialization. Also, get a device name. Currently in a somewhat
+	  hackish fashion, but I didn't really find something better.
+
 2004-03-14  Thomas Vander Stichele  <thomas at apestaart dot org>
 
 	* *.c, *.h: run gst-indent

ext/alsa/gstalsa.c

@@ -273,11 +273,7 @@ gst_alsa_get_property (GObject * object, guint prop_id, GValue * value,
       g_value_set_string (value, this->device);
       break;
     case ARG_DEVICE_NAME:
-      if (GST_STATE (this) != GST_STATE_NULL) {
+      g_value_set_string (value, this->cardname);
-	g_value_set_string (value, snd_pcm_info_get_name (this->info));
-      } else {
-	g_value_set_string (value, NULL);
-      }
       break;
     case ARG_PERIODCOUNT:
       g_value_set_int (value, this->period_count);
@@ -1108,9 +1104,16 @@ gst_alsa_set_eos (GstAlsa * this)
 static gboolean
 gst_alsa_open_audio (GstAlsa * this)
 {
+  snd_pcm_info_t *info;
+
   g_assert (this != NULL);
   g_assert (this->handle == NULL);
 
+  /* If we have no pads, then we're apparently a mixer object,
+   * and that doesn't need a handle to the actual audio device. */
+  if (!gst_element_get_pad_list (GST_ELEMENT (this)))
+    return TRUE;
+
   GST_INFO ("Opening alsa device \"%s\"...\n", this->device);
 
 #if 0
@@ -1127,8 +1130,10 @@ gst_alsa_open_audio (GstAlsa * this)
     return FALSE;
   }
 
-  snd_pcm_info_malloc (&this->info);
+  snd_pcm_info_malloc (&info);
-  snd_pcm_info (this->handle, this->info);
+  snd_pcm_info (this->handle, info);
+  this->cardname = g_strdup (snd_pcm_info_get_name (info));
+  snd_pcm_info_free (info);
 
   GST_FLAG_SET (this, GST_ALSA_OPEN);
   return TRUE;
@@ -1375,14 +1380,20 @@ gst_alsa_stop_audio (GstAlsa * this)
 static gboolean
 gst_alsa_close_audio (GstAlsa * this)
 {
+  /* if there's no pads, we never open. So we don't close either. */
+  if (!gst_element_get_pad_list (GST_ELEMENT (this)))
+    return TRUE;
+
   g_return_val_if_fail (this != NULL, FALSE);
   g_return_val_if_fail (this->handle != NULL, FALSE);
 
-  snd_pcm_info_free (this->info);
   ERROR_CHECK (snd_pcm_close (this->handle), "Error closing device: %s");
 
   this->handle = NULL;
-  this->info = NULL;
+  if (this->cardname) {
+    g_free (this->cardname);
+    this->cardname = NULL;
+  }
   GST_FLAG_UNSET (this, GST_ALSA_OPEN);
 
   return TRUE;
@@ -1399,6 +1410,7 @@ gst_alsa_get_formats (GstPad * pad)
     GST_FORMAT_BYTES,
     0
   };
+
   return formats;
 }
 
@@ -1483,6 +1495,7 @@ gst_alsa_get_query_types (GstPad * pad)
     GST_QUERY_POSITION,
     0,
   };
+
   return query_types;
 }
 

ext/alsa/gstalsamixer.c

@@ -34,7 +34,6 @@ static void gst_alsa_interface_init (GstImplementsInterfaceClass * klass);
 
 static void gst_alsa_mixer_class_init (gpointer g_class, gpointer class_data);
 static void gst_alsa_mixer_init (GstAlsaMixer * mixer);
-static void gst_alsa_mixer_dispose (GObject * object);
 static void gst_alsa_mixer_interface_init (GstMixerClass * klass);
 static gboolean gst_alsa_mixer_supported (GstImplementsInterface * iface,
     GType iface_type);
@@ -117,8 +116,6 @@ gst_alsa_mixer_class_init (gpointer g_class, gpointer class_data)
   if (parent_class == NULL)
     parent_class = g_type_class_ref (GST_TYPE_ALSA);
 
-  object_class->dispose = gst_alsa_mixer_dispose;
-
   element_class->change_state = gst_alsa_mixer_change_state;
 
   gst_element_class_set_details (element_class, &gst_alsa_mixer_details);
@@ -127,7 +124,13 @@ gst_alsa_mixer_class_init (gpointer g_class, gpointer class_data)
 static void
 gst_alsa_mixer_init (GstAlsaMixer * mixer)
 {
-  gint err;
+  mixer->mixer_handle = NULL;
+}
+
+static gboolean
+gst_alsa_mixer_open (GstAlsaMixer * mixer)
+{
+  gint err, device;
   GstAlsa *alsa = GST_ALSA (mixer);
 
   mixer->mixer_handle = (snd_mixer_t *) - 1;
@@ -137,7 +140,7 @@ gst_alsa_mixer_init (GstAlsaMixer * mixer)
   if (err < 0 || mixer->mixer_handle == NULL) {
     GST_ERROR_OBJECT (GST_OBJECT (mixer), "Cannot open mixer device.");
     mixer->mixer_handle = (snd_mixer_t *) - 1;
-    return;
+    return FALSE;
   }
 
   if ((err = snd_mixer_attach (mixer->mixer_handle, alsa->device)) < 0) {
@@ -156,25 +159,37 @@ gst_alsa_mixer_init (GstAlsaMixer * mixer)
     goto error;
   }
 
-  return;
+  /* I don't know how to get a device name from a mixer handle. So on
+   * to the ugly hacks here, then... */
+  if (sscanf (alsa->device, "hw:%d", &device) == 1) {
+    gchar *name;
+
+    if (!snd_card_get_name (device, &name))
+      alsa->cardname = name;
+  }
+
+  return TRUE;
 
 error:
   snd_mixer_close (mixer->mixer_handle);
   mixer->mixer_handle = (snd_mixer_t *) - 1;
+  return FALSE;
 }
 
 static void
-gst_alsa_mixer_dispose (GObject * object)
+gst_alsa_mixer_close (GstAlsaMixer * mixer)
 {
-  GstAlsaMixer *mixer = GST_ALSA_MIXER (object);
+  GstAlsa *alsa = GST_ALSA (mixer);
 
   if (((gint) mixer->mixer_handle) == -1)
     return;
 
+  if (alsa->cardname) {
+    g_free (alsa->cardname);
+    alsa->cardname = NULL;
+  }
   snd_mixer_close (mixer->mixer_handle);
   mixer->mixer_handle = (snd_mixer_t *) - 1;
-
-  G_OBJECT_CLASS (parent_class)->dispose (object);
 }
 
 static void
@@ -278,13 +293,16 @@ gst_alsa_mixer_change_state (GstElement * element)
 
   switch (GST_STATE_TRANSITION (element)) {
     case GST_STATE_NULL_TO_READY:
+      if (!gst_alsa_mixer_open (this))
+	return GST_STATE_FAILURE;
       gst_alsa_mixer_build_list (this);
       break;
     case GST_STATE_READY_TO_NULL:
       gst_alsa_mixer_free_list (this);
+      gst_alsa_mixer_close (this);
       break;
     default:
-      g_assert_not_reached ();
+      break;
   }
 
   if (GST_ELEMENT_CLASS (parent_class)->change_state)