sys/oss4/: Make device-name probing in NULL state work better (e.g. for the gnome-control-center sound capplet).

Original commit message from CVS:
* sys/oss4/oss4-mixer.c: (gst_oss4_mixer_open):
* sys/oss4/oss4-property-probe.c:
(gst_oss4_property_probe_find_device_name),
(gst_oss4_property_probe_find_device_name_nofd):
* sys/oss4/oss4-property-probe.h:
* sys/oss4/oss4-sink.c: (gst_oss4_sink_get_property):
* sys/oss4/oss4-source.c: (gst_oss4_source_get_property):
Make device-name probing in NULL state work better (e.g. for the
gnome-control-center sound capplet).

sys/oss4/oss4-mixer.c

@@ -303,6 +303,9 @@ open_failed:
       GST_ELEMENT_ERROR (mixer, RESOURCE, OPEN_READ_WRITE,
           (_("Could not open audio device for mixer control handling.")),
           GST_ERROR_SYSTEM);
+    } else {
+      GST_DEBUG_OBJECT (mixer, "open failed: %s (ignoring errors)",
+          g_strerror (errno));
     }
     g_free (device);
     return FALSE;
@@ -315,6 +318,8 @@ legacy_oss:
           (_("Could not open audio device for mixer control handling."
                   "This version of the Open Sound System is not supported by this "
                   "element.")), ("Try the 'ossmixer' element instead"));
+    } else {
+      GST_DEBUG_OBJECT (mixer, "open failed: legacy oss (ignoring errors)");
     }
     g_free (device);
     return FALSE;

sys/oss4/oss4-property-probe.c

@@ -163,6 +163,24 @@ gst_oss4_property_probe_find_device_name (GstObject * obj, int fd,
   return (name != NULL);
 }
 
+gboolean
+gst_oss4_property_probe_find_device_name_nofd (GstObject * obj,
+    const gchar * device_handle, gchar ** device_name)
+{
+  gboolean res;
+  int fd;
+
+  fd = open ("/dev/mixer", O_RDONLY);
+  if (fd < 0)
+    return FALSE;
+
+  res = gst_oss4_property_probe_find_device_name (obj, fd, device_handle,
+      device_name);
+
+  close (fd);
+  return res;
+}
+
 static GList *
 gst_oss4_property_probe_get_mixer_devices (GstObject * obj, int fd,
     struct oss_sysinfo *si)

sys/oss4/oss4-property-probe.h

@@ -29,6 +29,10 @@ gboolean  gst_oss4_property_probe_find_device_name (GstObject   * obj,
                                                     const gchar * device_handle,
                                                     gchar      ** device_name);
 
+gboolean  gst_oss4_property_probe_find_device_name_nofd (GstObject   * obj,
+                                                         const gchar * device_handle,
+                                                         gchar      ** device_name);
+
 #endif /* GST_OSS4_PROPERTY_PROBE_H */
 
 

sys/oss4/oss4-sink.c

@@ -255,7 +255,12 @@ gst_oss4_sink_get_property (GObject * object, guint prop_id,
           g_value_set_string (value, oss->device_name);
           gst_oss4_sink_close (GST_AUDIO_SINK (oss));
         } else {
-          g_value_set_string (value, oss->device_name);
+          gchar *name = NULL;
+
+          gst_oss4_property_probe_find_device_name_nofd (GST_OBJECT (oss),
+              oss->device, &name);
+          g_value_set_string (value, name);
+          g_free (name);
         }
       } else {
         g_value_set_string (value, oss->device_name);

sys/oss4/oss4-source.c

@@ -256,11 +256,17 @@ gst_oss4_source_get_property (GObject * object, guint prop_id,
           g_value_set_string (value, oss->device_name);
           gst_oss4_source_close (GST_AUDIO_SRC (oss));
         } else {
-          g_value_set_string (value, NULL);
+          gchar *name = NULL;
+
+          gst_oss4_property_probe_find_device_name_nofd (GST_OBJECT (oss),
+              oss->device, &name);
+          g_value_set_string (value, name);
+          g_free (name);
         }
       } else {
         g_value_set_string (value, oss->device_name);
       }
+
       GST_OBJECT_UNLOCK (oss);
       break;
     default: