gstreamer_core/gst/gstobject.c
changeset 0 0e761a78d257
child 8 4a7fac7dd34a
child 29 567bb019e3e3
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gstreamer_core/gst/gstobject.c	Thu Dec 17 08:53:32 2009 +0200
@@ -0,0 +1,1294 @@
+/* GStreamer
+ * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
+ *                    2000 Wim Taymans <wtay@chello.be>
+ *                    2005 Wim Taymans <wim@fluendo.com>
+ *
+ * gstobject.c: Fundamental class used for all of GStreamer
+ *
+ * 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.
+ */
+
+/**
+ * SECTION:gstobject
+ * @short_description: Base class for the GStreamer object hierarchy
+ *
+ * #GstObject provides a root for the object hierarchy tree filed in by the
+ * GStreamer library.  It is currently a thin wrapper on top of
+ * #GObject. It is an abstract class that is not very usable on its own.
+ *
+ * #GstObject gives us basic refcounting, parenting functionality and locking.
+ * Most of the function are just extended for special GStreamer needs and can be
+ * found under the same name in the base class of #GstObject which is #GObject
+ * (e.g. g_object_ref() becomes gst_object_ref()).
+ *
+ * The most interesting difference between #GstObject and #GObject is the
+ * "floating" reference count. A #GObject is created with a reference count of
+ * 1, owned by the creator of the #GObject. (The owner of a reference is the
+ * code section that has the right to call gst_object_unref() in order to
+ * remove that reference.) A #GstObject is created with a reference count of 1
+ * also, but it isn't owned by anyone; Instead, the initial reference count
+ * of a #GstObject is "floating". The floating reference can be removed by
+ * anyone at any time, by calling gst_object_sink().  gst_object_sink() does
+ * nothing if an object is already sunk (has no floating reference).
+ *
+ * When you add a #GstElement to its parent container, the parent container will
+ * do this:
+ * <informalexample>
+ * <programlisting>
+ *   gst_object_ref (GST_OBJECT (child_element));
+ *   gst_object_sink (GST_OBJECT (child_element));
+ * </programlisting>
+ * </informalexample>
+ * This means that the container now owns a reference to the child element
+ * (since it called gst_object_ref()), and the child element has no floating
+ * reference.
+ *
+ * The purpose of the floating reference is to keep the child element alive
+ * until you add it to a parent container, which then manages the lifetime of
+ * the object itself:
+ * <informalexample>
+ * <programlisting>
+ *    element = gst_element_factory_make (factoryname, name);
+ *    // element has one floating reference to keep it alive
+ *    gst_bin_add (GST_BIN (bin), element);
+ *    // element has one non-floating reference owned by the container
+ * </programlisting>
+ * </informalexample>
+ *
+ * Another effect of this is, that calling gst_object_unref() on a bin object,
+ * will also destoy all the #GstElement objects in it. The same is true for
+ * calling gst_bin_remove().
+ *
+ * Special care has to be taken for all methods that gst_object_sink() an object
+ * since if the caller of those functions had a floating reference to the object,
+ * the object reference is now invalid.
+ *
+ * In contrast to #GObject instances, #GstObject adds a name property. The functions
+ * gst_object_set_name() and gst_object_get_name() are used to set/get the name
+ * of the object.
+ *
+ * Last reviewed on 2005-11-09 (0.9.4)
+ */
+
+
+#include "gst_private.h"
+
+#include "gstobject.h"
+#include "gstmarshal.h"
+#include "gstinfo.h"
+#include "gstutils.h"
+
+#ifdef __SYMBIAN32__
+#include <glib_global.h>
+#include <gobject_global.h>
+#endif
+
+#ifndef GST_DISABLE_TRACE
+#include "gsttrace.h"
+static GstAllocTrace *_gst_object_trace;
+#endif
+
+
+#define DEBUG_REFCOUNT
+
+/* Object signals and args */
+enum
+{
+  PARENT_SET,
+  PARENT_UNSET,
+#ifndef GST_DISABLE_LOADSAVE
+  OBJECT_SAVED,
+#endif
+  DEEP_NOTIFY,
+  LAST_SIGNAL
+};
+
+enum
+{
+  ARG_0,
+  ARG_NAME
+      /* FILL ME */
+};
+
+enum
+{
+  SO_OBJECT_LOADED,
+  SO_LAST_SIGNAL
+};
+
+/* maps type name quark => count */
+static GData *object_name_counts = NULL;
+
+G_LOCK_DEFINE_STATIC (object_name_mutex);
+
+typedef struct _GstSignalObject GstSignalObject;
+typedef struct _GstSignalObjectClass GstSignalObjectClass;
+
+static GType gst_signal_object_get_type (void);
+static void gst_signal_object_class_init (GstSignalObjectClass * klass);
+static void gst_signal_object_init (GstSignalObject * object);
+
+#ifndef GST_DISABLE_LOADSAVE
+static guint gst_signal_object_signals[SO_LAST_SIGNAL] = { 0 };
+#endif
+
+static void gst_object_class_init (GstObjectClass * klass);
+static void gst_object_init (GTypeInstance * instance, gpointer g_class);
+
+static void gst_object_set_property (GObject * object, guint prop_id,
+    const GValue * value, GParamSpec * pspec);
+static void gst_object_get_property (GObject * object, guint prop_id,
+    GValue * value, GParamSpec * pspec);
+static void gst_object_dispatch_properties_changed (GObject * object,
+    guint n_pspecs, GParamSpec ** pspecs);
+
+static void gst_object_dispose (GObject * object);
+static void gst_object_finalize (GObject * object);
+
+static gboolean gst_object_set_name_default (GstObject * object);
+
+#ifndef GST_DISABLE_LOADSAVE
+static void gst_object_real_restore_thyself (GstObject * object,
+    xmlNodePtr self);
+#endif
+
+static GObjectClass *parent_class = NULL;
+static guint gst_object_signals[LAST_SIGNAL] = { 0 };
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+
+GType
+gst_object_get_type (void)
+{
+  static GType gst_object_type = 0;
+
+  if (G_UNLIKELY (gst_object_type == 0)) {
+    static const GTypeInfo object_info = {
+      sizeof (GstObjectClass),
+      NULL,
+      NULL,
+      (GClassInitFunc) gst_object_class_init,
+      NULL,
+      NULL,
+      sizeof (GstObject),
+      0,
+      gst_object_init,
+      NULL
+    };
+
+    gst_object_type =
+        g_type_register_static (G_TYPE_OBJECT, "GstObject", &object_info,
+        G_TYPE_FLAG_ABSTRACT);
+  }
+  return gst_object_type;
+}
+
+static void
+gst_object_class_init (GstObjectClass * klass)
+{
+  GObjectClass *gobject_class;
+
+  gobject_class = G_OBJECT_CLASS (klass);
+
+  parent_class = g_type_class_peek_parent (klass);
+
+#ifndef GST_DISABLE_TRACE
+  _gst_object_trace = gst_alloc_trace_register (g_type_name (GST_TYPE_OBJECT));
+#endif
+
+  gobject_class->set_property = GST_DEBUG_FUNCPTR (gst_object_set_property);
+  gobject_class->get_property = GST_DEBUG_FUNCPTR (gst_object_get_property);
+
+  g_object_class_install_property (gobject_class, ARG_NAME,
+      g_param_spec_string ("name", "Name", "The name of the object",
+          NULL, G_PARAM_READWRITE | G_PARAM_CONSTRUCT));
+
+  /**
+   * GstObject::parent-set:
+   * @gstobject: a #GstObject
+   * @parent: the new parent
+   *
+   * Emitted when the parent of an object is set.
+   */
+  gst_object_signals[PARENT_SET] =
+      g_signal_new ("parent-set", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
+      G_STRUCT_OFFSET (GstObjectClass, parent_set), NULL, NULL,
+      g_cclosure_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_OBJECT);
+
+  /**
+   * GstObject::parent-unset:
+   * @gstobject: a #GstObject
+   * @parent: the old parent
+   *
+   * Emitted when the parent of an object is unset.
+   */
+  gst_object_signals[PARENT_UNSET] =
+      g_signal_new ("parent-unset", G_TYPE_FROM_CLASS (klass),
+      G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstObjectClass, parent_unset), NULL,
+      NULL, g_cclosure_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_OBJECT);
+
+#ifndef GST_DISABLE_LOADSAVE
+  /**
+   * GstObject::object-saved:
+   * @gstobject: a #GstObject
+   * @xml_node: the xmlNodePtr of the parent node
+   *
+   * Trigered whenever a new object is saved to XML. You can connect to this
+   * signal to insert custom XML tags into the core XML.
+   */
+  /* FIXME This should be the GType of xmlNodePtr instead of G_TYPE_POINTER
+   *       (if libxml would use GObject)
+   */
+  gst_object_signals[OBJECT_SAVED] =
+      g_signal_new ("object-saved", G_TYPE_FROM_CLASS (klass),
+      G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstObjectClass, object_saved), NULL,
+      NULL, g_cclosure_marshal_VOID__POINTER, G_TYPE_NONE, 1, G_TYPE_POINTER);
+
+  klass->restore_thyself = gst_object_real_restore_thyself;
+#endif
+
+  /**
+   * GstObject::deep-notify:
+   * @gstobject: a #GstObject
+   * @prop_object: the object that originated the signal
+   * @prop: the property that changed
+   *
+   * The deep notify signal is used to be notified of property changes. It is
+   * typically attached to the toplevel bin to receive notifications from all
+   * the elements contained in that bin.
+   */
+  gst_object_signals[DEEP_NOTIFY] =
+      g_signal_new ("deep-notify", G_TYPE_FROM_CLASS (klass),
+      G_SIGNAL_RUN_FIRST | G_SIGNAL_NO_RECURSE | G_SIGNAL_DETAILED |
+      G_SIGNAL_NO_HOOKS, G_STRUCT_OFFSET (GstObjectClass, deep_notify), NULL,
+      NULL, gst_marshal_VOID__OBJECT_PARAM, G_TYPE_NONE, 2, GST_TYPE_OBJECT,
+      G_TYPE_PARAM);
+
+  klass->path_string_separator = "/";
+  klass->lock = g_new0 (GStaticRecMutex, 1);
+  g_static_rec_mutex_init (klass->lock);
+
+  klass->signal_object = g_object_new (gst_signal_object_get_type (), NULL);
+
+  /* see the comments at gst_object_dispatch_properties_changed */
+  gobject_class->dispatch_properties_changed
+      = GST_DEBUG_FUNCPTR (gst_object_dispatch_properties_changed);
+
+  gobject_class->dispose = gst_object_dispose;
+  gobject_class->finalize = gst_object_finalize;
+}
+
+static void
+gst_object_init (GTypeInstance * instance, gpointer g_class)
+{
+  GstObject *object = GST_OBJECT (instance);
+
+  object->lock = g_mutex_new ();
+  object->parent = NULL;
+  object->name = NULL;
+  GST_CAT_LOG_OBJECT (GST_CAT_REFCOUNTING, object, "%p new", object);
+
+#ifndef GST_DISABLE_TRACE
+  gst_alloc_trace_new (_gst_object_trace, object);
+#endif
+
+  object->flags = 0;
+  GST_OBJECT_FLAG_SET (object, GST_OBJECT_FLOATING);
+}
+
+/**
+ * gst_object_ref:
+ * @object: a #GstObject to reference
+ *
+ * Increments the reference count on @object. This function
+ * does not take the lock on @object because it relies on
+ * atomic refcounting.
+ *
+ * This object returns the input parameter to ease writing
+ * constructs like :
+ *  result = gst_object_ref (object->parent);
+ *
+ * Returns: A pointer to @object
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+gpointer
+gst_object_ref (gpointer object)
+{
+  g_return_val_if_fail (object != NULL, NULL);
+
+#ifdef DEBUG_REFCOUNT
+  GST_CAT_LOG_OBJECT (GST_CAT_REFCOUNTING, object, "%p ref %d->%d",
+      object,
+      ((GObject *) object)->ref_count, ((GObject *) object)->ref_count + 1);
+#endif
+  g_object_ref (object);
+
+  return object;
+}
+
+/**
+ * gst_object_unref:
+ * @object: a #GstObject to unreference
+ *
+ * Decrements the reference count on @object.  If reference count hits
+ * zero, destroy @object. This function does not take the lock
+ * on @object as it relies on atomic refcounting.
+ *
+ * The unref method should never be called with the LOCK held since
+ * this might deadlock the dispose function.
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+void
+gst_object_unref (gpointer object)
+{
+  g_return_if_fail (object != NULL);
+  g_return_if_fail (((GObject *) object)->ref_count > 0);
+
+#ifdef DEBUG_REFCOUNT
+  GST_CAT_LOG_OBJECT (GST_CAT_REFCOUNTING, object, "%p unref %d->%d",
+      object,
+      ((GObject *) object)->ref_count, ((GObject *) object)->ref_count - 1);
+#endif
+  g_object_unref (object);
+}
+
+/**
+ * gst_object_sink:
+ * @object: a #GstObject to sink
+ *
+ * If @object was floating, the #GST_OBJECT_FLOATING flag is removed
+ * and @object is unreffed. When @object was not floating,
+ * this function does nothing.
+ *
+ * Any newly created object has a refcount of 1 and is floating.
+ * This function should be used when creating a new object to
+ * symbolically 'take ownership' of @object. This done by first doing a
+ * gst_object_ref() to keep a reference to @object and then gst_object_sink()
+ * to remove and unref any floating references to @object.
+ * Use gst_object_set_parent() to have this done for you.
+ *
+ * MT safe. This function grabs and releases @object lock.
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+void
+gst_object_sink (gpointer object)
+{
+  g_return_if_fail (GST_IS_OBJECT (object));
+
+  GST_CAT_LOG_OBJECT (GST_CAT_REFCOUNTING, object, "sink");
+
+  GST_OBJECT_LOCK (object);
+  if (G_LIKELY (GST_OBJECT_IS_FLOATING (object))) {
+    GST_CAT_LOG_OBJECT (GST_CAT_REFCOUNTING, object, "clear floating flag");
+    GST_OBJECT_FLAG_UNSET (object, GST_OBJECT_FLOATING);
+    GST_OBJECT_UNLOCK (object);
+    gst_object_unref (object);
+  } else {
+    GST_OBJECT_UNLOCK (object);
+  }
+}
+
+/**
+ * gst_object_replace:
+ * @oldobj: pointer to a place of a #GstObject to replace
+ * @newobj: a new #GstObject
+ *
+ * Unrefs the #GstObject pointed to by @oldobj, refs @newobj and
+ * puts @newobj in *@oldobj. Be carefull when calling this
+ * function, it does not take any locks. You might want to lock
+ * the object owning @oldobj pointer before calling this
+ * function.
+ *
+ * Make sure not to LOCK @oldobj because it might be unreffed
+ * which could cause a deadlock when it is disposed.
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+void
+gst_object_replace (GstObject ** oldobj, GstObject * newobj)
+{
+  g_return_if_fail (oldobj != NULL);
+  g_return_if_fail (*oldobj == NULL || GST_IS_OBJECT (*oldobj));
+  g_return_if_fail (newobj == NULL || GST_IS_OBJECT (newobj));
+
+#ifdef DEBUG_REFCOUNT
+  GST_CAT_LOG (GST_CAT_REFCOUNTING, "replace %s (%d) with %s (%d)",
+      *oldobj ? GST_STR_NULL (GST_OBJECT_NAME (*oldobj)) : "(NONE)",
+      *oldobj ? G_OBJECT (*oldobj)->ref_count : 0,
+      newobj ? GST_STR_NULL (GST_OBJECT_NAME (newobj)) : "(NONE)",
+      newobj ? G_OBJECT (newobj)->ref_count : 0);
+#endif
+
+  if (G_LIKELY (*oldobj != newobj)) {
+    if (newobj)
+      gst_object_ref (newobj);
+    if (*oldobj)
+      gst_object_unref (*oldobj);
+
+    *oldobj = newobj;
+  }
+}
+
+/* dispose is called when the object has to release all links
+ * to other objects */
+static void
+gst_object_dispose (GObject * object)
+{
+  GstObject *parent;
+
+  GST_CAT_LOG_OBJECT (GST_CAT_REFCOUNTING, object, "dispose");
+
+  GST_OBJECT_LOCK (object);
+  if ((parent = GST_OBJECT_PARENT (object)))
+    goto have_parent;
+  GST_OBJECT_PARENT (object) = NULL;
+  GST_OBJECT_UNLOCK (object);
+
+  parent_class->dispose (object);
+
+  return;
+
+  /* ERRORS */
+have_parent:
+  {
+    g_critical ("\nTrying to dispose object \"%s\", but it still has a "
+        "parent \"%s\".\nYou need to let the parent manage the "
+        "object instead of unreffing the object directly.\n",
+        GST_OBJECT_NAME (object), GST_OBJECT_NAME (parent));
+    GST_OBJECT_UNLOCK (object);
+    /* ref the object again to revive it in this error case */
+    object = gst_object_ref (object);
+    return;
+  }
+}
+
+/* finalize is called when the object has to free its resources */
+static void
+gst_object_finalize (GObject * object)
+{
+  GstObject *gstobject = GST_OBJECT (object);
+
+  GST_CAT_LOG_OBJECT (GST_CAT_REFCOUNTING, object, "finalize");
+
+  g_signal_handlers_destroy (object);
+
+  g_free (gstobject->name);
+  g_mutex_free (gstobject->lock);
+
+#ifndef GST_DISABLE_TRACE
+  gst_alloc_trace_free (_gst_object_trace, object);
+#endif
+
+  parent_class->finalize (object);
+}
+
+/* Changing a GObject property of a GstObject will result in "deep_notify"
+ * signals being emitted by the object itself, as well as in each parent
+ * object. This is so that an application can connect a listener to the
+ * top-level bin to catch property-change notifications for all contained
+ * elements.
+ *
+ * This function is not MT safe in glib < 2.8 so we need to lock it with a
+ * classwide mutex in that case.
+ *
+ * MT safe.
+ */
+static void
+gst_object_dispatch_properties_changed (GObject * object,
+    guint n_pspecs, GParamSpec ** pspecs)
+{
+  GstObject *gst_object, *parent, *old_parent;
+  guint i;
+  gchar *name, *debug_name;
+  GstObjectClass *klass;
+
+  /* we fail when this is not a GstObject */
+  g_return_if_fail (GST_IS_OBJECT (object));
+
+  klass = GST_OBJECT_GET_CLASS (object);
+
+  /* do the standard dispatching */
+  G_OBJECT_CLASS (parent_class)->dispatch_properties_changed (object, n_pspecs,
+      pspecs);
+
+  gst_object = GST_OBJECT_CAST (object);
+  name = gst_object_get_name (gst_object);
+  debug_name = GST_STR_NULL (name);
+
+  /* now let the parent dispatch those, too */
+  parent = gst_object_get_parent (gst_object);
+  while (parent) {
+    for (i = 0; i < n_pspecs; i++) {
+      GST_LOG_OBJECT (parent, "deep notification from %s (%s)",
+          debug_name, pspecs[i]->name);
+
+      g_signal_emit (parent, gst_object_signals[DEEP_NOTIFY],
+          g_quark_from_string (pspecs[i]->name), GST_OBJECT_CAST (object),
+          pspecs[i]);
+    }
+
+    old_parent = parent;
+    parent = gst_object_get_parent (old_parent);
+    gst_object_unref (old_parent);
+  }
+  g_free (name);
+}
+
+/**
+ * gst_object_default_deep_notify:
+ * @object: the #GObject that signalled the notify.
+ * @orig: a #GstObject that initiated the notify.
+ * @pspec: a #GParamSpec of the property.
+ * @excluded_props: a set of user-specified properties to exclude or
+ *  NULL to show all changes.
+ *
+ * A default deep_notify signal callback for an object. The user data
+ * should contain a pointer to an array of strings that should be excluded
+ * from the notify. The default handler will print the new value of the property
+ * using g_print.
+ *
+ * MT safe. This function grabs and releases @object's LOCK for getting its
+ *          path string.
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+void
+gst_object_default_deep_notify (GObject * object, GstObject * orig,
+    GParamSpec * pspec, gchar ** excluded_props)
+{
+  GValue value = { 0, };        /* the important thing is that value.type = 0 */
+  gchar *str = NULL;
+  gchar *name = NULL;
+
+  if (pspec->flags & G_PARAM_READABLE) {
+    /* let's not print these out for excluded properties... */
+    while (excluded_props != NULL && *excluded_props != NULL) {
+      if (strcmp (pspec->name, *excluded_props) == 0)
+        return;
+      excluded_props++;
+    }
+    g_value_init (&value, G_PARAM_SPEC_VALUE_TYPE (pspec));
+    g_object_get_property (G_OBJECT (orig), pspec->name, &value);
+
+    if (G_IS_PARAM_SPEC_ENUM (pspec)) {
+      GEnumValue *enum_value;
+
+      enum_value =
+          g_enum_get_value (G_ENUM_CLASS (g_type_class_ref (pspec->value_type)),
+          g_value_get_enum (&value));
+
+      str = g_strdup_printf ("%s (%d)", enum_value->value_nick,
+          enum_value->value);
+    } else {
+      str = g_strdup_value_contents (&value);
+    }
+    name = gst_object_get_path_string (orig);
+    g_print ("%s: %s = %s\n", name, pspec->name, str);
+    g_free (name);
+    g_free (str);
+    g_value_unset (&value);
+  } else {
+    name = gst_object_get_path_string (orig);
+    g_warning ("Parameter %s not readable in %s.", pspec->name, name);
+    g_free (name);
+  }
+}
+
+static gboolean
+gst_object_set_name_default (GstObject * object)
+{
+  const gchar *type_name;
+  gint count;
+  gchar *name, *tmp;
+  gboolean result;
+  GQuark q;
+
+  /* to ensure guaranteed uniqueness across threads, only one thread
+   * may ever assign a name */
+  G_LOCK (object_name_mutex);
+
+  if (!object_name_counts) {
+    g_datalist_init (&object_name_counts);
+  }
+
+  q = g_type_qname (G_OBJECT_TYPE (object));
+  count = GPOINTER_TO_INT (g_datalist_id_get_data (&object_name_counts, q));
+  g_datalist_id_set_data (&object_name_counts, q, GINT_TO_POINTER (count + 1));
+
+  G_UNLOCK (object_name_mutex);
+
+  /* GstFooSink -> foosinkN */
+  type_name = g_quark_to_string (q);
+  if (strncmp (type_name, "Gst", 3) == 0)
+    type_name += 3;
+  tmp = g_strdup_printf ("%s%d", type_name, count);
+  name = g_ascii_strdown (tmp, strlen (tmp));
+  g_free (tmp);
+
+  result = gst_object_set_name (object, name);
+  g_free (name);
+
+  return result;
+}
+
+/**
+ * gst_object_set_name:
+ * @object: a #GstObject
+ * @name:   new name of object
+ *
+ * Sets the name of @object, or gives @object a guaranteed unique
+ * name (if @name is NULL).
+ * This function makes a copy of the provided name, so the caller
+ * retains ownership of the name it sent.
+ *
+ * Returns: TRUE if the name could be set. Since Objects that have
+ * a parent cannot be renamed, this function returns FALSE in those
+ * cases.
+ *
+ * MT safe.  This function grabs and releases @object's LOCK.
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+gboolean
+gst_object_set_name (GstObject * object, const gchar * name)
+{
+  gboolean result;
+
+  g_return_val_if_fail (GST_IS_OBJECT (object), FALSE);
+
+  GST_OBJECT_LOCK (object);
+
+  /* parented objects cannot be renamed */
+  if (G_UNLIKELY (object->parent != NULL))
+    goto had_parent;
+
+  if (name != NULL) {
+    g_free (object->name);
+    object->name = g_strdup (name);
+    GST_OBJECT_UNLOCK (object);
+    result = TRUE;
+  } else {
+    GST_OBJECT_UNLOCK (object);
+    result = gst_object_set_name_default (object);
+  }
+  return result;
+
+  /* error */
+had_parent:
+  {
+    GST_WARNING ("parented objects can't be renamed");
+    GST_OBJECT_UNLOCK (object);
+    return FALSE;
+  }
+}
+
+/**
+ * gst_object_get_name:
+ * @object: a #GstObject
+ *
+ * Returns a copy of the name of @object.
+ * Caller should g_free() the return value after usage.
+ * For a nameless object, this returns NULL, which you can safely g_free()
+ * as well.
+ *
+ * Returns: the name of @object. g_free() after usage.
+ *
+ * MT safe. This function grabs and releases @object's LOCK.
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif 
+gchar *
+gst_object_get_name (GstObject * object)
+{
+  gchar *result = NULL;
+
+  g_return_val_if_fail (GST_IS_OBJECT (object), NULL);
+
+  GST_OBJECT_LOCK (object);
+  result = g_strdup (object->name);
+  GST_OBJECT_UNLOCK (object);
+
+  return result;
+}
+
+/**
+ * gst_object_set_name_prefix:
+ * @object:      a #GstObject
+ * @name_prefix: new name prefix of @object
+ *
+ * Sets the name prefix of @object to @name_prefix.
+ * This function makes a copy of the provided name prefix, so the caller
+ * retains ownership of the name prefix it sent.
+ *
+ * MT safe.  This function grabs and releases @object's LOCK.
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+void
+gst_object_set_name_prefix (GstObject * object, const gchar * name_prefix)
+{
+  g_return_if_fail (GST_IS_OBJECT (object));
+
+  GST_OBJECT_LOCK (object);
+  g_free (object->name_prefix);
+  object->name_prefix = g_strdup (name_prefix); /* NULL gives NULL */
+  GST_OBJECT_UNLOCK (object);
+}
+
+/**
+ * gst_object_get_name_prefix:
+ * @object: a #GstObject
+ *
+ * Returns a copy of the name prefix of @object.
+ * Caller should g_free() the return value after usage.
+ * For a prefixless object, this returns NULL, which you can safely g_free()
+ * as well.
+ *
+ * Returns: the name prefix of @object. g_free() after usage.
+ *
+ * MT safe. This function grabs and releases @object's LOCK.
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+gchar *
+gst_object_get_name_prefix (GstObject * object)
+{
+  gchar *result = NULL;
+
+  g_return_val_if_fail (GST_IS_OBJECT (object), NULL);
+
+  GST_OBJECT_LOCK (object);
+  result = g_strdup (object->name_prefix);
+  GST_OBJECT_UNLOCK (object);
+
+  return result;
+}
+
+/**
+ * gst_object_set_parent:
+ * @object: a #GstObject
+ * @parent: new parent of object
+ *
+ * Sets the parent of @object to @parent. The object's reference count will
+ * be incremented, and any floating reference will be removed (see gst_object_sink()).
+ *
+ * This function causes the parent-set signal to be emitted when the parent
+ * was successfully set.
+ *
+ * Returns: TRUE if @parent could be set or FALSE when @object
+ * already had a parent or @object and @parent are the same.
+ *
+ * MT safe. Grabs and releases @object's LOCK.
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif 
+gboolean
+gst_object_set_parent (GstObject * object, GstObject * parent)
+{
+  g_return_val_if_fail (GST_IS_OBJECT (object), FALSE);
+  g_return_val_if_fail (GST_IS_OBJECT (parent), FALSE);
+  g_return_val_if_fail (object != parent, FALSE);
+
+  GST_CAT_DEBUG_OBJECT (GST_CAT_REFCOUNTING, object,
+      "set parent (ref and sink)");
+
+  GST_OBJECT_LOCK (object);
+  if (G_UNLIKELY (object->parent != NULL))
+    goto had_parent;
+
+  /* sink object, we don't call our own function because we don't
+   * need to release/acquire the lock needlessly or touch the refcount
+   * in the floating case. */
+  object->parent = parent;
+  if (G_LIKELY (GST_OBJECT_IS_FLOATING (object))) {
+    GST_CAT_LOG_OBJECT (GST_CAT_REFCOUNTING, object, "unsetting floating flag");
+    GST_OBJECT_FLAG_UNSET (object, GST_OBJECT_FLOATING);
+    GST_OBJECT_UNLOCK (object);
+  } else {
+    GST_OBJECT_UNLOCK (object);
+    gst_object_ref (object);
+  }
+
+  g_signal_emit (G_OBJECT (object), gst_object_signals[PARENT_SET], 0, parent);
+
+  return TRUE;
+
+  /* ERROR handling */
+had_parent:
+  {
+    GST_CAT_DEBUG_OBJECT (GST_CAT_REFCOUNTING, object,
+        "set parent failed, object already had a parent");
+    GST_OBJECT_UNLOCK (object);
+    return FALSE;
+  }
+}
+
+/**
+ * gst_object_get_parent:
+ * @object: a #GstObject
+ *
+ * Returns the parent of @object. This function increases the refcount
+ * of the parent object so you should gst_object_unref() it after usage.
+ *
+ * Returns: parent of @object, this can be NULL if @object has no
+ *   parent. unref after usage.
+ *
+ * MT safe. Grabs and releases @object's LOCK.
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+GstObject *
+gst_object_get_parent (GstObject * object)
+{
+  GstObject *result = NULL;
+
+  g_return_val_if_fail (GST_IS_OBJECT (object), NULL);
+
+  GST_OBJECT_LOCK (object);
+  result = object->parent;
+  if (G_LIKELY (result))
+    gst_object_ref (result);
+  GST_OBJECT_UNLOCK (object);
+
+  return result;
+}
+
+/**
+ * gst_object_unparent:
+ * @object: a #GstObject to unparent
+ *
+ * Clear the parent of @object, removing the associated reference.
+ * This function decreases the refcount of @object.
+ *
+ * MT safe. Grabs and releases @object's lock.
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif 
+void
+gst_object_unparent (GstObject * object)
+{
+  GstObject *parent;
+
+  g_return_if_fail (GST_IS_OBJECT (object));
+
+  GST_OBJECT_LOCK (object);
+  parent = object->parent;
+
+  if (G_LIKELY (parent != NULL)) {
+    GST_CAT_LOG_OBJECT (GST_CAT_REFCOUNTING, object, "unparent");
+    object->parent = NULL;
+    GST_OBJECT_UNLOCK (object);
+
+    g_signal_emit (G_OBJECT (object), gst_object_signals[PARENT_UNSET], 0,
+        parent);
+
+    gst_object_unref (object);
+  } else {
+    GST_OBJECT_UNLOCK (object);
+  }
+}
+
+/**
+ * gst_object_has_ancestor:
+ * @object: a #GstObject to check
+ * @ancestor: a #GstObject to check as ancestor
+ *
+ * Check if @object has an ancestor @ancestor somewhere up in
+ * the hierarchy.
+ *
+ * Returns: TRUE if @ancestor is an ancestor of @object.
+ *
+ * MT safe. Grabs and releases @object's locks.
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+gboolean
+gst_object_has_ancestor (GstObject * object, GstObject * ancestor)
+{
+  GstObject *parent;
+  gboolean result = FALSE;
+
+  if (object == NULL)
+    return FALSE;
+
+  if (object == ancestor)
+    return TRUE;
+
+  parent = gst_object_get_parent (object);
+  result = gst_object_has_ancestor (parent, ancestor);
+  if (parent)
+    gst_object_unref (parent);
+
+  return result;
+}
+
+/**
+ * gst_object_check_uniqueness:
+ * @list: a list of #GstObject to check through
+ * @name: the name to search for
+ *
+ * Checks to see if there is any object named @name in @list. This function
+ * does not do any locking of any kind. You might want to protect the
+ * provided list with the lock of the owner of the list. This function
+ * will lock each #GstObject in the list to compare the name, so be
+ * carefull when passing a list with a locked object.
+ *
+ * Returns: TRUE if a #GstObject named @name does not appear in @list,
+ * FALSE if it does.
+ *
+ * MT safe. Grabs and releases the LOCK of each object in the list.
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+gboolean
+gst_object_check_uniqueness (GList * list, const gchar * name)
+{
+  gboolean result = TRUE;
+
+  g_return_val_if_fail (name != NULL, FALSE);
+
+  for (; list; list = g_list_next (list)) {
+    GstObject *child;
+    gboolean eq;
+
+    child = GST_OBJECT (list->data);
+
+    GST_OBJECT_LOCK (child);
+    eq = strcmp (GST_OBJECT_NAME (child), name) == 0;
+    GST_OBJECT_UNLOCK (child);
+
+    if (G_UNLIKELY (eq)) {
+      result = FALSE;
+      break;
+    }
+  }
+  return result;
+}
+
+
+#ifndef GST_DISABLE_LOADSAVE
+/**
+ * gst_object_save_thyself:
+ * @object: a #GstObject to save
+ * @parent: The parent XML node to save @object into
+ *
+ * Saves @object into the parent XML node.
+ *
+ * Returns: the new xmlNodePtr with the saved object
+ */
+xmlNodePtr
+gst_object_save_thyself (GstObject * object, xmlNodePtr parent)
+{
+  GstObjectClass *oclass;
+
+  g_return_val_if_fail (GST_IS_OBJECT (object), parent);
+  g_return_val_if_fail (parent != NULL, parent);
+
+  oclass = GST_OBJECT_GET_CLASS (object);
+
+  if (oclass->save_thyself)
+    oclass->save_thyself (object, parent);
+
+  g_signal_emit (G_OBJECT (object), gst_object_signals[OBJECT_SAVED], 0,
+      parent);
+
+  return parent;
+}
+
+/**
+ * gst_object_restore_thyself:
+ * @object: a #GstObject to load into
+ * @self: The XML node to load @object from
+ *
+ * Restores @object with the data from the parent XML node.
+ */
+void
+gst_object_restore_thyself (GstObject * object, xmlNodePtr self)
+{
+  GstObjectClass *oclass;
+
+  g_return_if_fail (GST_IS_OBJECT (object));
+  g_return_if_fail (self != NULL);
+
+  oclass = GST_OBJECT_GET_CLASS (object);
+
+  if (oclass->restore_thyself)
+    oclass->restore_thyself (object, self);
+}
+
+static void
+gst_object_real_restore_thyself (GstObject * object, xmlNodePtr self)
+{
+  g_return_if_fail (GST_IS_OBJECT (object));
+  g_return_if_fail (self != NULL);
+
+  gst_class_signal_emit_by_name (object, "object_loaded", self);
+}
+#endif /* GST_DISABLE_LOADSAVE */
+
+static void
+gst_object_set_property (GObject * object, guint prop_id,
+    const GValue * value, GParamSpec * pspec)
+{
+  GstObject *gstobject;
+
+  gstobject = GST_OBJECT (object);
+
+  switch (prop_id) {
+    case ARG_NAME:
+      gst_object_set_name (gstobject, g_value_get_string (value));
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
+
+static void
+gst_object_get_property (GObject * object, guint prop_id,
+    GValue * value, GParamSpec * pspec)
+{
+  GstObject *gstobject;
+
+  gstobject = GST_OBJECT (object);
+
+  switch (prop_id) {
+    case ARG_NAME:
+      g_value_take_string (value, gst_object_get_name (gstobject));
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
+
+/**
+ * gst_object_get_path_string:
+ * @object: a #GstObject
+ *
+ * Generates a string describing the path of @object in
+ * the object hierarchy. Only useful (or used) for debugging.
+ *
+ * Returns: a string describing the path of @object. You must
+ *          g_free() the string after usage.
+ *
+ * MT safe. Grabs and releases the #GstObject's LOCK for all objects
+ *          in the hierarchy.
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+gchar *
+gst_object_get_path_string (GstObject * object)
+{
+  GSList *parentage;
+  GSList *parents;
+  void *parent;
+  gchar *prevpath, *path;
+  gchar *component;
+  gchar *separator;
+
+  /* ref object before adding to list */
+  gst_object_ref (object);
+  parentage = g_slist_prepend (NULL, object);
+
+  path = g_strdup ("");
+
+  /* first walk the object hierarchy to build a list of the parents,
+   * be carefull here with refcounting. */
+  do {
+    if (GST_IS_OBJECT (object)) {
+      parent = gst_object_get_parent (object);
+      /* add parents to list, refcount remains increased while
+       * we handle the object */
+      if (parent)
+        parentage = g_slist_prepend (parentage, parent);
+    } else {
+      break;
+    }
+    object = parent;
+  } while (object != NULL);
+
+  /* then walk the parent list and print them out. we need to
+   * decrease the refcounting on each element after we handled
+   * it. */
+  for (parents = parentage; parents; parents = g_slist_next (parents)) {
+    if (GST_IS_OBJECT (parents->data)) {
+      GstObject *item = GST_OBJECT_CAST (parents->data);
+      GstObjectClass *oclass = GST_OBJECT_GET_CLASS (item);
+
+      component = gst_object_get_name (item);
+      separator = oclass->path_string_separator;
+      /* and unref now */
+      gst_object_unref (item);
+    } else {
+      component = g_strdup_printf ("%p", parents->data);
+      separator = "/";
+    }
+
+    prevpath = path;
+    path = g_strjoin (separator, prevpath, component, NULL);
+    g_free (prevpath);
+    g_free (component);
+  }
+
+  g_slist_free (parentage);
+
+  return path;
+}
+
+
+struct _GstSignalObject
+{
+  GObject object;
+};
+
+struct _GstSignalObjectClass
+{
+  GObjectClass parent_class;
+
+  /* signals */
+#ifndef GST_DISABLE_LOADSAVE
+  void (*object_loaded) (GstSignalObject * object, GstObject * new,
+      xmlNodePtr self);
+#endif
+};
+
+static GType
+gst_signal_object_get_type (void)
+{
+  static GType signal_object_type = 0;
+
+  if (G_UNLIKELY (signal_object_type == 0)) {
+    static const GTypeInfo signal_object_info = {
+      sizeof (GstSignalObjectClass),
+      NULL,
+      NULL,
+      (GClassInitFunc) gst_signal_object_class_init,
+      NULL,
+      NULL,
+      sizeof (GstSignalObject),
+      0,
+      (GInstanceInitFunc) gst_signal_object_init,
+      NULL
+    };
+
+    signal_object_type =
+        g_type_register_static (G_TYPE_OBJECT, "GstSignalObject",
+        &signal_object_info, 0);
+  }
+  return signal_object_type;
+}
+
+static void
+gst_signal_object_class_init (GstSignalObjectClass * klass)
+{
+  GObjectClass *gobject_class;
+
+  gobject_class = (GObjectClass *) klass;
+
+  parent_class = g_type_class_peek_parent (klass);
+
+#ifndef GST_DISABLE_LOADSAVE
+  gst_signal_object_signals[SO_OBJECT_LOADED] =
+      g_signal_new ("object-loaded", G_TYPE_FROM_CLASS (klass),
+      G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstSignalObjectClass, object_loaded),
+      NULL, NULL, gst_marshal_VOID__OBJECT_POINTER, G_TYPE_NONE, 2,
+      G_TYPE_OBJECT, G_TYPE_POINTER);
+#endif
+}
+
+static void
+gst_signal_object_init (GstSignalObject * object)
+{
+}
+
+/**
+ * gst_class_signal_connect
+ * @klass: a #GstObjectClass to attach the signal to
+ * @name: the name of the signal to attach to
+ * @func: the signal function
+ * @func_data: a pointer to user data
+ *
+ * Connect to a class signal.
+ *
+ * Returns: the signal id.
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+guint
+gst_class_signal_connect (GstObjectClass * klass,
+    const gchar * name, gpointer func, gpointer func_data)
+{
+  /* [0.11] func parameter needs to be changed to a GCallback *
+   * doing so now would be an API break. */
+  return g_signal_connect (klass->signal_object, name, G_CALLBACK (func),
+      func_data);
+}
+
+#ifndef GST_DISABLE_LOADSAVE
+/**
+ * gst_class_signal_emit_by_name:
+ * @object: a #GstObject that emits the signal
+ * @name: the name of the signal to emit
+ * @self: data for the signal
+ *
+ * emits the named class signal.
+ */
+void
+gst_class_signal_emit_by_name (GstObject * object,
+    const gchar * name, xmlNodePtr self)
+{
+  GstObjectClass *oclass;
+
+  oclass = GST_OBJECT_GET_CLASS (object);
+
+  g_signal_emit_by_name (oclass->signal_object, name, object, self);
+}
+
+#endif /* GST_DISABLE_LOADSAVE */