gstreamer/gst/gstobject.c

/* GStreamer
 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
 *                    2000 Wim Taymans <wtay@chello.be>
 *
 * 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.
 */

#include "gst_private.h"

#include "gstobject.h"

/* Object signals and args */
enum {
  PARENT_SET,
  OBJECT_SAVED,
  LAST_SIGNAL
};

enum {
  ARG_0,
  /* FILL ME */
};

enum {
  SO_OBJECT_LOADED,
  SO_LAST_SIGNAL
};

typedef struct _GstSignalObject GstSignalObject;
typedef struct _GstSignalObjectClass GstSignalObjectClass;

static GtkType		gst_signal_object_get_type	(void);
static void		gst_signal_object_class_init	(GstSignalObjectClass *klass);
static void		gst_signal_object_init		(GstSignalObject *object);

static guint gst_signal_object_signals[SO_LAST_SIGNAL] = { 0 };

static void		gst_object_class_init		(GstObjectClass *klass);
static void		gst_object_init			(GstObject *object);

static void 		gst_object_real_destroy 	(GtkObject *gtk_object);
static void 		gst_object_shutdown 		(GtkObject *gtk_object);
static void 		gst_object_finalize 		(GtkObject *gtk_object);

static GtkObjectClass *parent_class = NULL;
static guint gst_object_signals[LAST_SIGNAL] = { 0 };

void
gst_object_inititialize (void)
{
}

GtkType
gst_object_get_type (void)
{
  static GtkType object_type = 0;

  if (!object_type) {
    static const GtkTypeInfo object_info = {
      "GstObject",
      sizeof(GstObject),
      sizeof(GstObjectClass),
      (GtkClassInitFunc)gst_object_class_init,
      (GtkObjectInitFunc)gst_object_init,
      (GtkArgSetFunc)NULL,
      (GtkArgGetFunc)NULL,
      (GtkClassInitFunc)NULL,
    };
    object_type = gtk_type_unique(gtk_object_get_type(),&object_info);
  }
  return object_type;
}

static void
gst_object_class_init (GstObjectClass *klass)
{
  GtkObjectClass *gtkobject_class;

  gtkobject_class = (GtkObjectClass*) klass;

  parent_class = gtk_type_class (gtk_object_get_type ());

  gst_object_signals[PARENT_SET] =
    gtk_signal_new ("parent_set", GTK_RUN_LAST, gtkobject_class->type,
                    GTK_SIGNAL_OFFSET (GstObjectClass, parent_set),
                    gtk_marshal_NONE__POINTER, GTK_TYPE_NONE, 1,
                    GST_TYPE_OBJECT);
  gst_object_signals[OBJECT_SAVED] =
    gtk_signal_new ("object_saved", GTK_RUN_LAST, gtkobject_class->type,
                    GTK_SIGNAL_OFFSET (GstObjectClass, object_saved),
                    gtk_marshal_NONE__POINTER, GTK_TYPE_NONE, 1,
                    GTK_TYPE_POINTER);
  gtk_object_class_add_signals (gtkobject_class, gst_object_signals, LAST_SIGNAL);

  klass->path_string_separator = "/";
  klass->signal_object = gtk_type_new (gst_signal_object_get_type ());

  gtkobject_class->shutdown = gst_object_shutdown;
  gtkobject_class->destroy = gst_object_real_destroy;
  gtkobject_class->finalize = gst_object_finalize;
}

static void
gst_object_init (GstObject *object)
{
  GstObjectClass *oclass;

  oclass = GST_OBJECT_CLASS (GTK_OBJECT (object)->klass);

  object->lock = g_mutex_new();
#ifdef HAVE_ATOMIC_H
  atomic_set(&(object->refcount),1);
#else
  object->refcount = 1;
#endif
  object->parent = NULL;

  object->flags = 0;
  GST_FLAG_SET (object, GST_FLOATING);
}

/**
 * gst_object_new:
 *
 * Create a new, empty object.  Not very useful, should never be used.
 *
 * Returns: new object
 */
GstObject*
gst_object_new (void)
{
  return GST_OBJECT (gtk_type_new (gst_object_get_type ()));
}

/**
 * gst_object_ref:
 * @object: GstObject to reference
 *
 * Increments the refence count on the object.
 */
GstObject*
gst_object_ref (GstObject *object)
{
  g_return_val_if_fail (GST_IS_OBJECT (object), NULL);

  GST_DEBUG (GST_CAT_REFCOUNTING, "ref '%s' %d->%d\n",GST_OBJECT_NAME(object),
             GTK_OBJECT(object)->ref_count,GTK_OBJECT(object)->ref_count+1);

  gtk_object_ref (GTK_OBJECT (object));

  return object;
}
#define gst_object_ref gst_object_ref

/**
 * gst_object_unref:
 * @object: GstObject to unreference
 *
 * Decrements the refence count on the object.  If reference count hits
 * zero, destroy the object.
 */
void
gst_object_unref (GstObject *object)
{
  g_return_if_fail (GST_IS_OBJECT (object));

  GST_DEBUG (GST_CAT_REFCOUNTING, "unref '%s' %d->%d\n",GST_OBJECT_NAME(object),
             GTK_OBJECT(object)->ref_count,GTK_OBJECT(object)->ref_count-1);

  gtk_object_unref (GTK_OBJECT (object));
}
#define gst_object_unref gst_object_unref

/**
 * gst_object_sink:
 * @object: GstObject to sink
 *
 * Removes floating reference on an object.  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' the object.
 */
void
gst_object_sink (GstObject *object)
{
  g_return_if_fail (object != NULL);
  g_return_if_fail (GST_IS_OBJECT (object));

  GST_DEBUG (GST_CAT_REFCOUNTING, "sink '%s'\n",GST_OBJECT_NAME(object));
  if (GST_OBJECT_FLOATING (object))
  {
    GST_FLAG_UNSET (object, GST_FLOATING);
    gst_object_unref (object);
  }
}

void
gst_object_destroy (GstObject *object)
{
  g_return_if_fail (object != NULL);
  g_return_if_fail (GST_IS_OBJECT (object));

  GST_DEBUG (GST_CAT_REFCOUNTING, "destroy '%s'\n",GST_OBJECT_NAME(object));
  if (!GST_OBJECT_DESTROYED (object))
  {
    /* need to hold a reference count around all class method
     * invocations.
     */
    gst_object_ref (object);
    GTK_OBJECT (object)->klass->shutdown (GTK_OBJECT (object));
    gst_object_unref (object);
  }
}

static void
gst_object_shutdown (GtkObject *object)
{
  GST_DEBUG (GST_CAT_REFCOUNTING, "shutdown '%s'\n",GST_OBJECT_NAME(object));
  GST_FLAG_SET (GST_OBJECT (object), GST_DESTROYED);
  parent_class->shutdown (GTK_OBJECT (object));
}

/* finilize is called when the object has to free its resources */
static void
gst_object_real_destroy (GtkObject *gtk_object)
{
  GST_DEBUG (GST_CAT_REFCOUNTING, "destroy '%s'\n",GST_OBJECT_NAME(gtk_object));

  GST_OBJECT_PARENT (gtk_object) = NULL;

  parent_class->destroy (gtk_object);
}

/* finilize is called when the object has to free its resources */
static void
gst_object_finalize (GtkObject *gtk_object)
{
  GstObject *object;

  object = GST_OBJECT (gtk_object);

  GST_DEBUG (GST_CAT_REFCOUNTING, "finalize '%s'\n",GST_OBJECT_NAME(object));
  if (object->name != NULL)
    g_free (object->name);

  g_mutex_free (object->lock);

  parent_class->finalize (gtk_object);
}

/**
 * gst_object_set_name:
 * @object: GstObject to set the name of
 * @name: new name of object
 *
 * Set the name of the object.
 */
void
gst_object_set_name (GstObject *object, const gchar *name)
{
  g_return_if_fail (object != NULL);
  g_return_if_fail (GST_IS_OBJECT (object));
  g_return_if_fail (name != NULL);

  if (object->name != NULL)
    g_free (object->name);

  object->name = g_strdup (name);
}

/**
 * gst_object_get_name:
 * @object: GstObject to get the name of
 *
 * Get the name of the object.
 *
 * Returns: name of the object
 */
const gchar*
gst_object_get_name (GstObject *object)
{
  g_return_val_if_fail (object != NULL, NULL);
  g_return_val_if_fail (GST_IS_OBJECT (object), NULL);

  return object->name;
}

/**
 * gst_object_set_parent:
 * @object: GstObject to set parent of
 * @parent: new parent of object
 *
 * Set the parent of the object.  The object's reference count is
 * incremented.
 * signals the parent-set signal
 */
void
gst_object_set_parent (GstObject *object, GstObject *parent)
{
  g_return_if_fail (object != NULL);
  g_return_if_fail (GST_IS_OBJECT (object));
  g_return_if_fail (parent != NULL);
  g_return_if_fail (GST_IS_OBJECT (parent));
  g_return_if_fail (object != parent);

  if (object->parent != NULL) {
    GST_ERROR_OBJECT (object,object->parent, "object's parent is already set, must unparent first");
    return;
  }

  gst_object_ref (object);
  gst_object_sink (object);
  object->parent = parent;

  gtk_signal_emit (GTK_OBJECT (object), gst_object_signals[PARENT_SET], parent);
}

/**
 * gst_object_get_parent:
 * @object: GstObject to get parent of
 *
 * Return the parent of the object.
 *
 * Returns: parent of the object
 */
GstObject*
gst_object_get_parent (GstObject *object)
{
  g_return_val_if_fail (object != NULL, NULL);
  g_return_val_if_fail (GST_IS_OBJECT (object), NULL);

  return object->parent;
}

/**
 * gst_object_unparent:
 * @object: GstObject to unparent
 *
 * Clear the parent of the object, removing the associated reference.
 */
void
gst_object_unparent (GstObject *object)
{
  g_return_if_fail (object != NULL);
  g_return_if_fail (GST_IS_OBJECT(object));
  if (object->parent == NULL)
    return;

  object->parent = NULL;
  gst_object_unref (object);
}

/**
 * gst_object_ref:
 * @object: GstObject to reference
 *
 * Increments the refence count on the object.
 */
#ifndef gst_object_ref
void
gst_object_ref (GstObject *object)
{
  g_return_if_fail (object != NULL);
  g_return_if_fail (GST_IS_OBJECT (object));

#ifdef HAVE_ATOMIC_H
  g_return_if_fail (atomic_read (&(object->refcount)) > 0);
  atomic_inc (&(object->refcount))
#else
  g_return_if_fail (object->refcount > 0);
  GST_LOCK (object);
  object->refcount++;
  GST_UNLOCK (object);
#endif
}
#endif /* gst_object_ref */

/**
 * gst_object_unref:
 * @object: GstObject to unreference
 *
 * Decrements the refence count on the object.  If reference count hits
 * zero, destroy the object.
 */
#ifndef gst_object_unref
void
gst_object_unref (GstObject *object)
{
  int reftest;

  g_return_if_fail (object != NULL);
  g_return_if_fail (GST_IS_OBJECT (object));

#ifdef HAVE_ATOMIC_H
  g_return_if_fail (atomic_read (&(object->refcount)) > 0);
  reftest = atomic_dec_and_test (&(object->refcount))
#else
  g_return_if_fail (object->refcount > 0);
  GST_LOCK (object);
  object->refcount--;
  reftest = (object->refcount == 0);
  GST_UNLOCK (object);
#endif

  /* if we ended up with the refcount at zero */
  if (reftest) {
    /* get the count to 1 for gtk_object_destroy() */
#ifdef HAVE_ATOMIC_H
    atomic_set (&(object->refcount),1);
#else
    object->refcount = 1;
#endif
    /* destroy it */
    gtk_object_destroy (GTK_OBJECT (object));
    /* drop the refcount back to zero */
#ifdef HAVE_ATOMIC_H
    atomic_set (&(object->refcount),0);
#else
    object->refcount = 0;
#endif
    /* finalize the object */
    // FIXME this is an evil hack that should be killed
// FIXMEFIXMEFIXMEFIXME
//    gtk_object_finalize(GTK_OBJECT(object));
  }
}
#endif /* gst_object_unref */

/**
 * gst_object_check_uniqueness:
 * @list: a list of #GstObject to check through
 * @name: the name to search for
 *
 * This function checks through the list of objects to see if the name
 * given appears in the list as the name of an object.  It returns TRUE if
 * the name does not exist in the list.
 *
 * Returns: TRUE if the name doesn't appear in the list, FALSE if it does.
 */
gboolean
gst_object_check_uniqueness (GList *list, const gchar *name)
{
  GstObject *child;

  while (list) {
    child = GST_OBJECT (list->data);
    list = g_list_next(list);
      
    if (strcmp(GST_OBJECT_NAME(child), name) == 0) return FALSE;
  }

  return TRUE;
}


/**
 * gst_object_save_thyself:
 * @object: GstObject to save
 * @parent: The parent XML node to save the object into
 *
 * Saves the given 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 (object != NULL, parent);
  g_return_val_if_fail (GST_IS_OBJECT (object), parent);
  g_return_val_if_fail (parent != NULL, parent);

  oclass = GST_OBJECT_CLASS (GTK_OBJECT (object)->klass);

  if (oclass->save_thyself)
    oclass->save_thyself (object, parent);

  gtk_signal_emit (GTK_OBJECT (object), gst_object_signals[OBJECT_SAVED], parent);

  return parent;
}

/**
 * gst_object_get_path_string:
 * @object: GstObject to get the path from
 *
 * Generates a string describing the path of the object in
 * the object hierarchy. Usefull for debugging
 *
 * Returns: a string describing the path of the object
 */
gchar*
gst_object_get_path_string (GstObject *object)
{
  GSList *parentage = NULL;
  GSList *parents;
  void *parent;
  gchar *prevpath, *path;
  const char *component;
  gchar *separator = "";
  gboolean free_component;

  parentage = g_slist_prepend (NULL, object);

  path = g_strdup ("");

  // first walk the object hierarchy to build a list of the parents
  do {
    if (GST_IS_OBJECT (object)) {
      parent = gst_object_get_parent (object);
    } else {
      parentage = g_slist_prepend (parentage, NULL);
      parent = NULL;
    }

    if (parent != NULL) {
      parentage = g_slist_prepend (parentage, parent);
    }

    object = parent;
  } while (object != NULL);

  // then walk the parent list and print them out
  parents = parentage;
  while (parents) {
    if (GST_IS_OBJECT (parents->data)) {
      GstObjectClass *oclass = GST_OBJECT_CLASS (GTK_OBJECT (parents->data)->klass);

      component = gst_object_get_name (parents->data);
      separator = oclass->path_string_separator;
      free_component = FALSE;
    } else {
      component = g_strdup_printf("%p",parents->data);
      separator = "/";
      free_component = TRUE;
    }

    prevpath = path;
    path = g_strjoin (separator, prevpath, component, NULL);
    g_free(prevpath);
    if (free_component)
      g_free((gchar *)component);

    parents = g_slist_next(parents);
  }

  g_slist_free (parentage);

  return path;
}



struct _GstSignalObject {
  GtkObject object;
};

struct _GstSignalObjectClass {
  GtkObjectClass        parent_class;

  /* signals */
  void          (*object_loaded)           (GstSignalObject *object, GstObject *new, xmlNodePtr self);
};

static GtkType
gst_signal_object_get_type (void)
{
  static GtkType signal_object_type = 0;

  if (!signal_object_type) {
    static const GtkTypeInfo signal_object_info = {
      "GstSignalObject",
      sizeof(GstSignalObject),
      sizeof(GstSignalObjectClass),
      (GtkClassInitFunc)gst_signal_object_class_init,
      (GtkObjectInitFunc)gst_signal_object_init,
      (GtkArgSetFunc)NULL,
      (GtkArgGetFunc)NULL,
      (GtkClassInitFunc)NULL,
    };
    signal_object_type = gtk_type_unique(gtk_object_get_type(),&signal_object_info);
  }
  return signal_object_type;
}

static void
gst_signal_object_class_init (GstSignalObjectClass *klass)
{
  GtkObjectClass *gtkobject_class;

  gtkobject_class = (GtkObjectClass*) klass;

  parent_class = gtk_type_class (gtk_object_get_type ());

  gst_signal_object_signals[SO_OBJECT_LOADED] =
    gtk_signal_new ("object_loaded", GTK_RUN_LAST, gtkobject_class->type,
                    GTK_SIGNAL_OFFSET (GstSignalObjectClass, object_loaded),
                    gtk_marshal_NONE__POINTER_POINTER, GTK_TYPE_NONE, 2,
                    GST_TYPE_OBJECT, GTK_TYPE_POINTER);
  gtk_object_class_add_signals (gtkobject_class, gst_signal_object_signals, LAST_SIGNAL);
}

static void
gst_signal_object_init (GstSignalObject *object)
{
}

/**
 * gst_class_signal_connect
 * @klass: the 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.
 */
guint
gst_class_signal_connect (GstObjectClass *klass,
			  const gchar    *name,
			  GtkSignalFunc  func,
		          gpointer       func_data)
{
  return gtk_signal_connect (klass->signal_object, name, func, func_data);
}

/**
 * gst_class_signal_emit_by_name:
 * @object: the object that sends 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_CLASS (GTK_OBJECT (object)->klass);

  gtk_signal_emit_by_name (oclass->signal_object, name, object, self);
}