gstreamer/gst/gstplugin.c

/* GStreamer
 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
 *                    2000 Wim Taymans <wtay@chello.be>
 *
 * gstplugin.c: Plugin subsystem for loading elements, types, and libs
 *
 * 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 <sys/types.h>
#include <sys/stat.h>
#include <dirent.h>
#include <unistd.h>

#undef RTLD_GLOBAL

#include "gst_private.h"
#include "gstplugin.h"
#include "gstversion.h"
#include "config.h"


/* list of loaded modules and its sequence number */
GList *_gst_modules;
gint _gst_modules_seqno;
/* global list of plugins and its sequence number */
GList *_gst_plugins;
gint _gst_plugins_seqno;
gint _gst_plugin_elementfactories = 0;
gint _gst_plugin_types = 0;
/* list of paths to check for plugins */
GList *_gst_plugin_paths;

GList *_gst_libraries;
gint _gst_libraries_seqno;

/* whether or not to spew library load issues */
gboolean _gst_plugin_spew = FALSE;

/* whether or not to warn if registry needs rebuild (gstreamer-register sets
 * this to false.) */
gboolean _gst_warn_old_registry = TRUE;

static gboolean plugin_times_older_than(time_t regtime);
static time_t get_time(const char * path);

void
_gst_plugin_initialize (void)
{
  xmlDocPtr doc;
  _gst_modules = NULL;
  _gst_modules_seqno = 0;
  _gst_plugins = NULL;
  _gst_plugins_seqno = 0;
  _gst_plugin_paths = NULL;
  _gst_libraries = NULL;
  _gst_libraries_seqno = 0;

  /* add the main (installed) library path */
  _gst_plugin_paths = g_list_prepend (_gst_plugin_paths, PLUGINS_DIR);

  /* if this is set, we add build-directory paths to the list */
#ifdef PLUGINS_USE_SRCDIR
  /* the catch-all plugins directory */
  _gst_plugin_paths = g_list_prepend (_gst_plugin_paths,
                                      PLUGINS_SRCDIR "/plugins");
  /* the libreary directory */
  _gst_plugin_paths = g_list_prepend (_gst_plugin_paths,
                                      PLUGINS_SRCDIR "/libs");
  /* location libgstelements.so */
  _gst_plugin_paths = g_list_prepend (_gst_plugin_paths,
                                      PLUGINS_SRCDIR "/gst/elements");
  _gst_plugin_paths = g_list_prepend (_gst_plugin_paths,
                                      PLUGINS_SRCDIR "/gst/types");
  _gst_plugin_paths = g_list_prepend (_gst_plugin_paths,
                                      PLUGINS_SRCDIR "/gst/autoplug");
#endif /* PLUGINS_USE_SRCDIR */

  doc = xmlParseFile (GST_CONFIG_DIR"/reg.xml");

  if (!doc || 
      !doc->xmlRootNode ||
      doc->xmlRootNode->name == 0 ||
      strcmp (doc->xmlRootNode->name, "GST-PluginRegistry") ||
      !plugin_times_older_than(get_time(GST_CONFIG_DIR"/reg.xml"))) {
    if (_gst_warn_old_registry)
	g_warning ("gstplugin: registry needs rebuild: run gstreamer-register\n");
    gst_plugin_load_all ();
    return;
  }
  gst_plugin_load_thyself (doc->xmlRootNode);

  xmlFreeDoc (doc);
}

/**
 * gst_plugin_add_path:
 * @path: the directory to add to the search path
 *
 * Add a directory to the path searched for plugins.
 */
void
gst_plugin_add_path (const gchar *path)
{
  _gst_plugin_paths = g_list_prepend (_gst_plugin_paths,g_strdup(path));
}

static time_t
get_time(const char * path)
{
  struct stat statbuf;
  if (stat(path, &statbuf)) return 0;
  if (statbuf.st_mtime > statbuf.st_ctime) return statbuf.st_mtime;
  return statbuf.st_ctime;
}

static gboolean
plugin_times_older_than_recurse(gchar *path, time_t regtime)
{
  DIR *dir;
  struct dirent *dirent;
  gchar *pluginname;

  time_t pathtime = get_time(path);

  if (pathtime > regtime) {
    GST_INFO (GST_CAT_PLUGIN_LOADING,
	       "time for %s was %ld; more recent than registry time of %ld\n",
	       path, (long)pathtime, (long)regtime);
    return FALSE;
  }

  dir = opendir(path);
  if (dir) {
    while ((dirent = readdir(dir))) {
      /* don't want to recurse in place or backwards */
      if (strcmp(dirent->d_name,".") && strcmp(dirent->d_name,"..")) {
	pluginname = g_strjoin("/",path,dirent->d_name,NULL);
	if (!plugin_times_older_than_recurse(pluginname , regtime)) {
          g_free (pluginname);
          closedir(dir);
          return FALSE;
        }
        g_free (pluginname);
      }
    }
    closedir(dir);
  }
  return TRUE;
}

static gboolean
plugin_times_older_than(time_t regtime)
{
  // return true iff regtime is more recent than the times of all the files
  // in the plugin dirs.
  GList *path;
  path = _gst_plugin_paths;
  while (path != NULL) {
    GST_DEBUG (GST_CAT_PLUGIN_LOADING,
	       "comparing plugin times from %s with %ld\n",
	       (gchar *)path->data, (long) regtime);
    if(!plugin_times_older_than_recurse(path->data, regtime))
	return FALSE;
    path = g_list_next(path);
  }
  return TRUE;
}

static gboolean
gst_plugin_load_recurse (gchar *directory, gchar *name)
{
  DIR *dir;
  struct dirent *dirent;
  gboolean loaded = FALSE;
  gchar *dirname;

  //g_print("recursive load of '%s' in '%s'\n", name, directory);
  dir = opendir(directory);
  if (dir) {
    while ((dirent = readdir(dir))) {
      /* don't want to recurse in place or backwards */
      if (strcmp(dirent->d_name,".") && strcmp(dirent->d_name,"..")) {
        dirname = g_strjoin("/",directory,dirent->d_name,NULL);
        loaded = gst_plugin_load_recurse(dirname,name);
        g_free(dirname);
	if (loaded && name) {
          closedir(dir);
          return TRUE;
        }
      }
    }
    closedir(dir);
  } else {
    if (strstr(directory,".so")) {
      gchar *temp;
      if (name) {
        if ((temp = strstr(directory,name)) &&
            (!strcmp(temp,name))) {
          loaded = gst_plugin_load_absolute(directory);
        }
      } else if ((temp = strstr(directory,".so")) &&
                 (!strcmp(temp,".so"))) {
        loaded = gst_plugin_load_absolute(directory);
      }
    }
  }
  return loaded;
}

/**
 * gst_plugin_load_all:
 *
 * Load all plugins in the path.
 */
void
gst_plugin_load_all(void)
{
  GList *path;

  path = _gst_plugin_paths;
  while (path != NULL) {
    GST_INFO (GST_CAT_PLUGIN_LOADING,"loading plugins from %s",(gchar *)path->data);
    gst_plugin_load_recurse(path->data,NULL);
    path = g_list_next(path);
  }
  GST_INFO (GST_CAT_PLUGIN_LOADING,"loaded %d plugins with %d elements and %d types",
       _gst_plugins_seqno,_gst_plugin_elementfactories,_gst_plugin_types);
}

/**
 * gst_library_load:
 * @name: name of library to load
 *
 * Load the named library.  Name should be given as
 * &quot;liblibrary.so&quot;.
 *
 * Returns: whether the library was loaded or not
 */
gboolean
gst_library_load (const gchar *name)
{
  gboolean res;
  GList *libraries = _gst_libraries;

  while (libraries) {
    if (!strcmp((gchar *)libraries->data, name)) return TRUE;

    libraries = g_list_next(libraries);
  }

  // for now this is the same
  res = gst_plugin_load(name);

  if (res) {
    _gst_libraries = g_list_prepend(_gst_libraries, g_strdup (name));
  }

  return res;
}

static void
gst_plugin_remove (GstPlugin *plugin)
{
  GList *factories;

  factories = plugin->elements;
  while (factories) {
    gst_elementfactory_destroy ((GstElementFactory*)(factories->data));
    factories = g_list_next(factories);
  }

  _gst_plugins = g_list_remove(_gst_plugins, plugin);

  // don't free the stuct because someone can have a handle to it
}

/**
 * gst_plugin_load:
 * @name: name of plugin to load
 *
 * Load the named plugin.  Name should be given as
 * &quot;libplugin.so&quot;.
 *
 * Returns: whether the plugin was loaded or not
 */
gboolean
gst_plugin_load (const gchar *name)
{
  GList *path;
  gchar *libspath;
  GstPlugin *plugin;
  gchar *pluginname;

  //g_print("attempting to load plugin '%s'\n",name);

  plugin = gst_plugin_find (name);

  if (plugin && plugin->loaded) return TRUE;

  path = _gst_plugin_paths;
  while (path != NULL) {
    pluginname = g_module_build_path(path->data,name);
    if (gst_plugin_load_absolute(pluginname)) {
      g_free(pluginname);
      return TRUE;
    }
    g_free(pluginname);
    libspath = g_strconcat(path->data,"/.libs",NULL);
    //g_print("trying to load '%s'\n",g_module_build_path(libspath,name));
    pluginname = g_module_build_path(libspath,name);
    g_free(libspath);
    if (gst_plugin_load_absolute(pluginname)) {
      g_free(pluginname);
      return TRUE;
    }
    g_free(pluginname);
    //g_print("trying to load '%s' from '%s'\n",name,path->data);
    pluginname = g_module_build_path("",name);
    if (gst_plugin_load_recurse(path->data,pluginname)) {
      g_free(pluginname);
      return TRUE;
    }
    g_free(pluginname);
    path = g_list_next(path);
  }
  return FALSE;
}

/**
 * gst_plugin_load_absolute:
 * @name: name of plugin to load
 *
 * Returns: whether or not the plugin loaded
 */
gboolean
gst_plugin_load_absolute (const gchar *name)
{
  GModule *module;
  GstPluginDesc *desc;
  GstPlugin *plugin;
  struct stat file_status;

  GST_INFO (GST_CAT_PLUGIN_LOADING,"plugin \"%s\" loading", name);

  if (g_module_supported() == FALSE) {
    g_warning("gstplugin: wow, you built this on a platform without dynamic loading???\n");
    return FALSE;
  }

  if (stat(name,&file_status)) {
    //g_print("problem opening file %s\n",name);
    return FALSE;
  }

  module = g_module_open(name,G_MODULE_BIND_LAZY);
  if (module != NULL) {
    if (g_module_symbol(module,"plugin_desc",(gpointer *)&desc)) {
      GST_INFO (GST_CAT_PLUGIN_LOADING,"loading plugin \"%s\"...", name);
      plugin = gst_plugin_new(desc->name, desc->major_version, desc->minor_version);
      if (plugin != NULL) {
        plugin->filename = g_strdup(name);
	if (!((desc->plugin_init)(module, plugin))) {
          GST_INFO (GST_CAT_PLUGIN_LOADING,"plugin \"%s\" failed to initialise",
             plugin->name);
	  g_free(plugin);
	  plugin = NULL;
	}
      }

      if (plugin != NULL) {
        GST_INFO (GST_CAT_PLUGIN_LOADING,"plugin \"%s\" loaded: %d elements, %d types",
             plugin->name,plugin->numelements,plugin->numtypes);
        plugin->loaded = TRUE;
        _gst_modules = g_list_prepend(_gst_modules,module);
        _gst_modules_seqno++;
        _gst_plugins = g_list_prepend(_gst_plugins,plugin);
        _gst_plugins_seqno++;
        _gst_plugin_elementfactories += plugin->numelements;
        _gst_plugin_types += plugin->numtypes;
        return TRUE;
      }
    }
    return TRUE;
  } else if (_gst_plugin_spew) {
    // FIXME this should be some standard gst mechanism!!!
    g_printerr ("error loading plugin %s, reason: %s\n", name, g_module_error());
  }
  else {
    GST_INFO (GST_CAT_PLUGIN_LOADING, "error loading plugin %s, reason: %s\n", name, g_module_error());
  }

  return FALSE;
}

/**
 * gst_plugin_new:
 * @name: name of new plugin
 * @major: major version number of core that plugin is compatible with
 * @minor: minor version number of core that plugin is compatible with
 *
 * Create a new plugin with given name.
 *
 * Returns: new plugin, or NULL if plugin couldn't be created, due to
 * incompatible version number, or name already being allocated)
 */
GstPlugin*
gst_plugin_new (const gchar *name, gint major, gint minor)
{
  GstPlugin *plugin;

  // return NULL if the major and minor version numbers are not compatible
  // with ours.
  if (major != GST_VERSION_MAJOR || minor != GST_VERSION_MINOR) return NULL;

  // return NULL if the plugin is allready loaded
  plugin = gst_plugin_find (name);
  if (plugin) return NULL;

  plugin = (GstPlugin *)g_malloc(sizeof(GstPlugin));

  plugin->name = g_strdup(name);
  plugin->longname = NULL;
  plugin->elements = NULL;
  plugin->numelements = 0;
  plugin->types = NULL;
  plugin->numtypes = 0;
  plugin->autopluggers = NULL;
  plugin->numautopluggers = 0;
  plugin->loaded = TRUE;

  return plugin;
}

/**
 * gst_plugin_get_name:
 * @plugin: plugin to get the name of
 *
 * Get the short name of the plugin
 *
 * Returns: the name of the plugin
 */
const gchar*
gst_plugin_get_name (GstPlugin *plugin)
{
  g_return_val_if_fail (plugin != NULL, NULL);

  return plugin->name;
}

/**
 * gst_plugin_set_name:
 * @plugin: plugin to set name of
 * @name: new name
 *
 * Sets the name (should be short) of the plugin.
 */
void
gst_plugin_set_name (GstPlugin *plugin, const gchar *name)
{
  g_return_if_fail (plugin != NULL);

  if (plugin->name)
    g_free (plugin->name);

  plugin->name = g_strdup (name);
}

/**
 * gst_plugin_set_longname:
 * @plugin: plugin to set long name of
 * @longname: new long name
 *
 * Sets the long name (should be descriptive) of the plugin.
 */
void
gst_plugin_set_longname (GstPlugin *plugin, const gchar *longname)
{
  g_return_if_fail(plugin != NULL);

  if (plugin->longname)
    g_free(plugin->longname);

  plugin->longname = g_strdup(longname);
}

/**
 * gst_plugin_get_longname:
 * @plugin: plugin to get long name of
 *
 * Get the long descriptive name of the plugin
 *
 * Returns: the long name of the plugin
 */
const gchar*
gst_plugin_get_longname (GstPlugin *plugin)
{
  g_return_val_if_fail (plugin != NULL, NULL);

  return plugin->longname;
}

/**
 * gst_plugin_get_filename:
 * @plugin: plugin to get the filename of
 *
 * get the filename of the plugin
 *
 * Returns: the filename of the plugin
 */
const gchar*
gst_plugin_get_filename (GstPlugin *plugin)
{
  g_return_val_if_fail (plugin != NULL, NULL);

  return plugin->filename;
}

/**
 * gst_plugin_is_loaded:
 * @plugin: plugin to query
 *
 * queries if the plugin is loaded into memory
 *
 * Returns: TRUE is loaded, FALSE otherwise
 */
gboolean
gst_plugin_is_loaded (GstPlugin *plugin)
{
  g_return_val_if_fail (plugin != NULL, FALSE);

  return plugin->loaded;
}


/**
 * gst_plugin_find:
 * @name: name of plugin to find
 *
 * Search the list of registered plugins for one of the given name
 *
 * Returns: pointer to the #GstPlugin if found, NULL otherwise
 */
GstPlugin*
gst_plugin_find (const gchar *name)
{
  GList *plugins = _gst_plugins;

  g_return_val_if_fail(name != NULL, NULL);

  while (plugins) {
    GstPlugin *plugin = (GstPlugin *)plugins->data;
//    g_print("plugin name is '%s'\n",plugin->name);
    if (plugin->name) {
      if (!strcmp(plugin->name,name)) {
        return plugin;
      }
    }
    plugins = g_list_next(plugins);
  }
  return NULL;
}

static GstElementFactory*
gst_plugin_find_elementfactory (const gchar *name)
{
  GList *plugins, *factories;
  GstElementFactory *factory;

  g_return_val_if_fail(name != NULL, NULL);

  plugins = _gst_plugins;
  while (plugins) {
    factories = ((GstPlugin *)(plugins->data))->elements;
    while (factories) {
      factory = (GstElementFactory*)(factories->data);
      if (!strcmp(factory->name, name))
        return (GstElementFactory*)(factory);
      factories = g_list_next(factories);
    }
    plugins = g_list_next(plugins);
  }

  return NULL;
}

/**
 * gst_plugin_load_elementfactory:
 * @name: name of elementfactory to load
 *
 * Load a registered elementfactory by name.
 *
 * Returns: @GstElementFactory if loaded, NULL if not
 */
GstElementFactory*
gst_plugin_load_elementfactory (const gchar *name)
{
  GList *plugins, *factories;
  GstElementFactory *factory = NULL;
  GstPlugin *plugin;

  g_return_val_if_fail(name != NULL, NULL);

  plugins = _gst_plugins;
  while (plugins) {
    plugin = (GstPlugin *)plugins->data;
    factories = plugin->elements;

    while (factories) {
      factory = (GstElementFactory*)(factories->data);

      if (!strcmp(factory->name,name)) {
	if (!plugin->loaded) {
          gchar *filename = g_strdup (plugin->filename);
	  gchar *pluginname = g_strdup (plugin->name);

          GST_INFO (GST_CAT_PLUGIN_LOADING,"loaded elementfactory %s from plugin %s",name,plugin->name);
	  gst_plugin_remove(plugin);
	  if (!gst_plugin_load_absolute(filename)) {
	    GST_DEBUG (0,"gstplugin: error loading element factory %s from plugin %s\n", name, pluginname);
	  }
	  g_free (pluginname);
	  g_free (filename);
	}
	factory = gst_plugin_find_elementfactory(name);
        return factory;
      }
      factories = g_list_next(factories);
    }
    plugins = g_list_next(plugins);
  }

  return factory;
}

static GstAutoplugFactory*
gst_plugin_find_autoplugfactory (const gchar *name)
{
  GList *plugins, *factories;
  GstAutoplugFactory *factory;

  g_return_val_if_fail(name != NULL, NULL);

  plugins = _gst_plugins;
  while (plugins) {
    factories = ((GstPlugin *)(plugins->data))->autopluggers;
    while (factories) {
      factory = (GstAutoplugFactory*)(factories->data);
      if (!strcmp(factory->name, name))
        return (GstAutoplugFactory*)(factory);
      factories = g_list_next(factories);
    }
    plugins = g_list_next(plugins);
  }

  return NULL;
}
/**
 * gst_plugin_load_autoplugfactory:
 * @name: name of autoplugfactory to load
 *
 * Load a registered autoplugfactory by name.
 *
 * Returns: @GstAutoplugFactory if loaded, NULL if not
 */
GstAutoplugFactory*
gst_plugin_load_autoplugfactory (const gchar *name)
{
  GList *plugins, *factories;
  GstAutoplugFactory *factory = NULL;
  GstPlugin *plugin;

  g_return_val_if_fail(name != NULL, NULL);

  plugins = _gst_plugins;
  while (plugins) {
    plugin = (GstPlugin *)plugins->data;
    factories = plugin->autopluggers;

    while (factories) {
      factory = (GstAutoplugFactory*)(factories->data);

      if (!strcmp(factory->name,name)) {
	if (!plugin->loaded) {
          gchar *filename = g_strdup (plugin->filename);
	  gchar *pluginname = g_strdup (plugin->name);

          GST_INFO (GST_CAT_PLUGIN_LOADING,"loaded autoplugfactory %s from plugin %s",name,plugin->name);
	  gst_plugin_remove(plugin);
	  if (!gst_plugin_load_absolute(filename)) {
	    GST_DEBUG (0,"gstplugin: error loading autoplug factory %s from plugin %s\n", name, pluginname);
	  }
	  g_free (pluginname);
	  g_free (filename);
	}
	factory = gst_plugin_find_autoplugfactory(name);
        return factory;
      }
      factories = g_list_next(factories);
    }
    plugins = g_list_next(plugins);
  }

  return factory;
}

/**
 * gst_plugin_load_typefactory:
 * @mime: name of typefactory to load
 *
 * Load a registered typefactory by mime type.
 */
void
gst_plugin_load_typefactory (const gchar *mime)
{
  GList *plugins, *factories;
  GstTypeFactory *factory;
  GstPlugin *plugin;

  g_return_if_fail (mime != NULL);

  plugins = g_list_copy (_gst_plugins);
  while (plugins) {
    plugin = (GstPlugin *)plugins->data;
    factories = g_list_copy (plugin->types);

    while (factories) {
      factory = (GstTypeFactory*)(factories->data);

      if (!strcmp(factory->mime,mime)) {
	if (!plugin->loaded) {
          gchar *filename = g_strdup (plugin->filename);
	  gchar *pluginname = g_strdup (plugin->name);

          GST_INFO (GST_CAT_PLUGIN_LOADING,"loading type factory for \"%s\" from plugin %s",mime,plugin->name);
	  plugin->loaded = TRUE;
	  gst_plugin_remove(plugin);
	  if (!gst_plugin_load_absolute(filename)) {
	    GST_DEBUG (0,"gstplugin: error loading type factory \"%s\" from plugin %s\n", mime, pluginname);
	  }
	  g_free (filename);
	  g_free (pluginname);
	}
	//return;
      }
      factories = g_list_next(factories);
    }

    g_list_free (factories);
    plugins = g_list_next(plugins);
  }
  g_list_free (plugins);

  return;
}

/**
 * gst_plugin_add_factory:
 * @plugin: plugin to add factory to
 * @factory: factory to add
 *
 * Add factory to the list of those provided by the plugin.
 */
void
gst_plugin_add_factory (GstPlugin *plugin, GstElementFactory *factory)
{
  g_return_if_fail (plugin != NULL);
  g_return_if_fail (factory != NULL);

//  g_print("adding factory to plugin\n");
  plugin->elements = g_list_prepend (plugin->elements, factory);
  plugin->numelements++;
}

/**
 * gst_plugin_add_type:
 * @plugin: plugin to add type to
 * @factory: the typefactory to add
 *
 * Add a typefactory to the list of those provided by the plugin.
 */
void
gst_plugin_add_type (GstPlugin *plugin, GstTypeFactory *factory)
{
  g_return_if_fail (plugin != NULL);
  g_return_if_fail (factory != NULL);

//  g_print("adding factory to plugin\n");
  plugin->types = g_list_prepend (plugin->types, factory);
  plugin->numtypes++;
  gst_type_register (factory);
}

/**
 * gst_plugin_add_autoplugger:
 * @plugin: plugin to add the autoplugger to
 * @factory: the autoplugfactory to add
 *
 * Add an autoplugfactory to the list of those provided by the plugin.
 */
void
gst_plugin_add_autoplugger (GstPlugin *plugin, GstAutoplugFactory *factory)
{
  g_return_if_fail (plugin != NULL);
  g_return_if_fail (factory != NULL);

//  g_print("adding factory to plugin\n");
  plugin->autopluggers = g_list_prepend (plugin->autopluggers, factory);
  plugin->numautopluggers++;
}

/**
 * gst_plugin_get_list:
 *
 * get the currently loaded plugins
 *
 * Returns; a GList of GstPlugin elements
 */
GList*
gst_plugin_get_list (void)
{
  return _gst_plugins;
}

/**
 * gst_plugin_save_thyself:
 * @parent: the parent node to save the plugin to
 *
 * saves the plugin into an XML representation
 *
 * Returns: the new XML node
 */
xmlNodePtr
gst_plugin_save_thyself (xmlNodePtr parent)
{
  xmlNodePtr tree, subtree;
  GList *plugins = NULL, *elements = NULL, *types = NULL, *autopluggers = NULL;

  plugins = gst_plugin_get_list ();
  while (plugins) {
    GstPlugin *plugin = (GstPlugin *)plugins->data;

    tree = xmlNewChild (parent, NULL, "plugin", NULL);
    xmlNewChild (tree, NULL, "name", plugin->name);
    xmlNewChild (tree, NULL, "longname", plugin->longname);
    xmlNewChild (tree, NULL, "filename", plugin->filename);

    types = plugin->types;
    while (types) {
      GstTypeFactory *factory = (GstTypeFactory *)types->data;
      subtree = xmlNewChild(tree, NULL, "typefactory", NULL);

      gst_typefactory_save_thyself (factory, subtree);

      types = g_list_next (types);
    }
    elements = plugin->elements;
    while (elements) {
      GstElementFactory *factory = (GstElementFactory *)elements->data;
      subtree = xmlNewChild (tree, NULL, "elementfactory", NULL);

      gst_elementfactory_save_thyself (factory, subtree);

      elements = g_list_next (elements);
    }
    autopluggers = plugin->autopluggers;
    while (autopluggers) {
      GstAutoplugFactory *factory = (GstAutoplugFactory *)autopluggers->data;
      subtree = xmlNewChild (tree, NULL, "autoplugfactory", NULL);

      gst_autoplugfactory_save_thyself (factory, subtree);

      autopluggers = g_list_next (autopluggers);
    }
    plugins = g_list_next (plugins);
  }
  return parent;
}

/**
 * gst_plugin_load_thyself:
 * @parent: the parent node to load the plugin from
 *
 * load the plugin from an XML representation
 */
void
gst_plugin_load_thyself (xmlNodePtr parent)
{
  xmlNodePtr kinderen;
  gint elementcount = 0;
  gint autoplugcount = 0;
  gint typecount = 0;
  gchar *pluginname;

  kinderen = parent->xmlChildrenNode; // Dutch invasion :-)
  while (kinderen) {
    if (!strcmp (kinderen->name, "plugin")) {
      xmlNodePtr field = kinderen->xmlChildrenNode;
      GstPlugin *plugin = g_new0 (GstPlugin, 1);

      plugin->elements = NULL;
      plugin->types = NULL;
      plugin->loaded = FALSE;

      while (field) {
	if (!strcmp (field->name, "name")) {
          pluginname = xmlNodeGetContent (field);
	  if (gst_plugin_find (pluginname)) {
            g_free (pluginname);
            g_free (plugin);
	    plugin = NULL;
            break;
	  } else {
	    plugin->name = pluginname;
	  }
	}
	else if (!strcmp (field->name, "longname")) {
	  plugin->longname = xmlNodeGetContent (field);
	}
	else if (!strcmp (field->name, "filename")) {
	  plugin->filename = xmlNodeGetContent (field);
	}
	else if (!strcmp (field->name, "elementfactory")) {
	  GstElementFactory *factory = gst_elementfactory_load_thyself (field);
	  gst_plugin_add_factory (plugin, factory);
	  elementcount++;
	}
	else if (!strcmp (field->name, "autoplugfactory")) {
	  GstAutoplugFactory *factory = gst_autoplugfactory_load_thyself (field);
	  gst_plugin_add_autoplugger (plugin, factory);
	  autoplugcount++;
	}
	else if (!strcmp (field->name, "typefactory")) {
	  GstTypeFactory *factory = gst_typefactory_load_thyself (field);
	  gst_plugin_add_type (plugin, factory);
	  elementcount++;
	  typecount++;
	}

	field = field->next;
      }

      if (plugin) {
        _gst_plugins = g_list_prepend (_gst_plugins, plugin);
      }
    }

    kinderen = kinderen->next;
  }
  GST_INFO (GST_CAT_PLUGIN_LOADING, "added %d registered factories, %d autopluggers and %d types",
		  elementcount, autoplugcount, typecount);
}


/**
 * gst_plugin_get_factory_list:
 * @plugin: the plugin to get the factories from
 *
 * get a list of all the factories that this plugin provides
 *
 * Returns: a GList of factories
 */
GList*
gst_plugin_get_factory_list (GstPlugin *plugin)
{
  g_return_val_if_fail (plugin != NULL, NULL);

  return plugin->elements;
}

/**
 * gst_plugin_get_type_list:
 * @plugin: the plugin to get the typefactories from
 *
 * get a list of all the typefactories that this plugin provides
 *
 * Returns: a GList of factories
 */
GList*
gst_plugin_get_type_list (GstPlugin *plugin)
{
  g_return_val_if_fail (plugin != NULL, NULL);

  return plugin->types;
}

/**
 * gst_plugin_get_autoplug_list:
 * @plugin: the plugin to get the autoplugfactories from
 *
 * get a list of all the autoplugfactories that this plugin provides
 *
 * Returns: a GList of factories
 */
GList*
gst_plugin_get_autoplug_list (GstPlugin *plugin)
{
  g_return_val_if_fail (plugin != NULL, NULL);

  return plugin->autopluggers;
}