First attempt (actually third) at a property probing interface

Original commit message from CVS:
First attempt (actually third) at a property probing interface

gst-libs/gst/propertyprobe/Makefile.am

@@ -0,0 +1,9 @@
+noinst_LTLIBRARIES = libgstpropertyprobe.la
+
+libgstpropertyprobe_la_SOURCES = propertyprobe.c
+
+libgstpropertyprobeincludedir = $(includedir)/gstreamer-@GST_MAJORMINOR@/gst/propertyprobe
+libgstpropertyprobeinclude_HEADERS = propertyprobe.h
+
+libgstpropertyprobe_la_CFLAGS = $(GST_CFLAGS)
+

gst-libs/gst/propertyprobe/propertyprobe.c

@@ -0,0 +1,176 @@
+/* GStreamer PropertyProbe
+ * Copyright (C) 2003 David Schleef <ds@schleef.org>
+ *
+ * property_probe.c: property_probe design virtual class function wrappers
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <gst/propertyprobe/propertyprobe.h>
+
+static void gst_property_probe_iface_init (GstPropertyProbeInterface *iface);
+
+enum {
+  NEED_PROBE,
+  LAST_SIGNAL
+};
+
+static guint gst_property_probe_signals[LAST_SIGNAL] = { 0 };
+
+GType
+gst_property_probe_get_type (void)
+{
+  static GType gst_property_probe_type = 0;
+
+  if (!gst_property_probe_type) {
+    static const GTypeInfo gst_property_probe_info = {
+      sizeof (GstPropertyProbeInterface),
+      (GBaseInitFunc) gst_property_probe_iface_init,
+      NULL,
+      NULL,
+      NULL,
+      NULL,
+      0,
+      0,
+      NULL,
+    };
+
+    gst_property_probe_type = g_type_register_static (G_TYPE_INTERFACE,
+					     "GstPropertyProbe",
+					     &gst_property_probe_info, 0);
+
+    g_type_interface_add_prerequisite (gst_property_probe_type, G_TYPE_OBJECT);
+  }
+
+  return gst_property_probe_type;
+}
+
+static void
+gst_property_probe_iface_init (GstPropertyProbeInterface *iface)
+{
+  static gboolean initialized = FALSE;
+
+  if (!initialized) {
+    gst_property_probe_signals[NEED_PROBE] =
+      g_signal_new ("need_probe",
+          GST_TYPE_PROPERTY_PROBE,
+          G_SIGNAL_RUN_LAST,
+          G_STRUCT_OFFSET (GstPropertyProbeInterface, need_probe),
+          NULL,
+          NULL,
+          gst_marshal_VOID__STRING,
+          G_TYPE_NONE, 1,
+          G_TYPE_STRING);
+
+    initialized = TRUE;
+  }
+
+  /* default virtual functions */
+  iface->get_list = NULL;
+  iface->probe_property = NULL;
+  iface->get_property_info = NULL;
+  iface->is_probed = NULL;
+}
+
+char **
+gst_property_probe_get_list (GstElement *element)
+{
+  GstPropertyProbeInterface *iface;
+  
+  g_return_val_if_fail (GST_IS_PROPERTY_PROBE (element), NULL);
+
+  iface = GST_PROPERTY_PROBE_GET_IFACE (element);
+  if (iface->get_list) {
+    return iface->get_list (element);
+  }
+
+  return NULL;
+}
+
+void
+gst_property_probe_probe_property (GstElement *element,
+    const char *property)
+{
+  GstPropertyProbeInterface *iface;
+  GParamSpec *ps;
+  
+  g_return_if_fail (GST_IS_PROPERTY_PROBE (element));
+  g_return_if_fail (GST_STATE (element) == GST_STATE_NULL);
+
+  ps = g_object_class_find_property (G_OBJECT_CLASS (element), property);
+  if (ps == NULL) return;
+  
+  iface = GST_PROPERTY_PROBE_GET_IFACE (element);
+  if (iface->probe_property) {
+    iface->probe_property (element, ps);
+  }
+}
+
+gchar **
+gst_property_probe_get_property_info (GstElement *element,
+    const gchar *property)
+{
+  GstPropertyProbeInterface *iface;
+  GParamSpec *ps;
+  
+  g_return_val_if_fail (GST_IS_PROPERTY_PROBE (element), NULL);
+
+  ps = g_object_class_find_property (G_OBJECT_CLASS (element), property);
+  if (ps == NULL) return NULL;
+  
+  iface = GST_PROPERTY_PROBE_GET_IFACE (element);
+  if (iface->get_property_info) {
+    return iface->get_property_info (element, ps);
+  }
+  return NULL;
+}
+
+gboolean
+gst_property_probe_is_probed (GstElement *element,
+    const char *property)
+{
+  GstPropertyProbeInterface *iface;
+  GParamSpec *ps;
+  
+  g_return_val_if_fail (GST_IS_PROPERTY_PROBE (element), FALSE);
+
+  ps = g_object_class_find_property (G_OBJECT_CLASS (element), property);
+  if (ps == NULL) return FALSE;
+
+  iface = GST_PROPERTY_PROBE_GET_IFACE (element);
+  if (iface->is_probed) {
+    return iface->is_probed (element, ps);
+  }
+  return FALSE;
+}
+
+gchar **
+gst_property_probe_get_possibilities (GstElement *element,
+    const char *property)
+{
+  g_return_val_if_fail (GST_IS_PROPERTY_PROBE (element), NULL);
+
+  if (!gst_property_probe_is_probed (element, property)){
+    gst_property_probe_probe_property (element, property);
+  }
+
+  return gst_property_probe_get_property_info (element, property);
+}
+

gst-libs/gst/propertyprobe/propertyprobe.h

@@ -0,0 +1,73 @@
+/* GStreamer PropertyProbe
+ * Copyright (C) 2003 David A. Schleef <ds@schleef.org>
+ *
+ * property_probe.h: property_probe interface design
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#ifndef __GST_PROPERTY_PROBE_H__
+#define __GST_PROPERTY_PROBE_H__
+
+#include <gst/gst.h>
+
+G_BEGIN_DECLS
+
+#define GST_TYPE_PROPERTY_PROBE \
+  (gst_property_probe_get_type ())
+#define GST_PROPERTY_PROBE(obj) \
+  (G_TYPE_CHECK_INSTANCE_CAST ((obj), GST_TYPE_PROPERTY_PROBE, GstPropertyProbe))
+#define GST_IS_PROPERTY_PROBE(obj) \
+  (G_TYPE_CHECK_INSTANCE_TYPE ((obj), GST_TYPE_PROPERTY_PROBE))
+#define GST_PROPERTY_PROBE_GET_IFACE(obj) \
+  (G_TYPE_INSTANCE_GET_INTERFACE ((obj), GST_TYPE_PROPERTY_PROBE, GstPropertyProbeInterface))
+
+typedef struct _GstPropertyProbe GstPropertyProbe; /* dummy typedef */
+
+typedef struct _GstPropertyProbeInterface {
+  GTypeInterface klass;
+
+  /* signals */
+  void (*need_probe) (GstPropertyProbe *property_probe, const gchar *property);
+
+  /* virtual functions */
+  gchar ** (*get_list) (GstElement *property_probe);
+  void (*probe_property) (GstElement *property_probe, const GParamSpec *property);
+  gchar ** (*get_property_info) (GstElement *property_probe,
+      const GParamSpec *property);
+  gboolean (*is_probed) (GstElement *element, const GParamSpec *property);
+  
+  GST_CLASS_PADDING
+} GstPropertyProbeInterface;
+
+GType		gst_property_probe_get_type	(void);
+
+/* virtual class function wrappers */
+gchar ** gst_property_probe_get_list (GstElement *element);
+void gst_property_probe_probe_property (GstElement *element,
+    const gchar *property);
+gchar ** gst_property_probe_get_property_info (GstElement *element,
+    const gchar *property);
+gboolean gst_property_probe_is_probed (GstElement *element,
+    const gchar *property);
+
+/* utility functions */
+gchar ** gst_property_probe_get_possibilities (GstElement *element,
+    const gchar *property);
+
+G_END_DECLS
+
+#endif /* __GST_PROPERTY_PROBE_H__ */