gstreamer/gst/gstplugin.c
Stefan Kost e719825726 more api documentation better error signaling and logging
Original commit message from CVS:
more api documentation
better error signaling and logging
2004-10-13 13:03:25 +00:00

890 lines
22 KiB
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.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <sys/types.h>
#include <sys/stat.h>
#ifdef HAVE_DIRENT_H
#include <dirent.h>
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <signal.h>
#include <errno.h>
#include "gst_private.h"
#include "gstplugin.h"
#include "gstversion.h"
#include "gstregistrypool.h"
#include "gstinfo.h"
#include "gstfilter.h"
#define GST_CAT_DEFAULT GST_CAT_PLUGIN_LOADING
static GModule *main_module = NULL;
static GList *_gst_plugin_static = NULL;
/* static variables for segfault handling of plugin loading */
static char *_gst_plugin_fault_handler_filename = NULL;
extern gboolean *_gst_disable_segtrap; /* see gst.c */
#ifndef HAVE_WIN32
static gboolean *_gst_plugin_fault_handler_is_setup = FALSE;
#endif
/* list of valid licenses.
* One of these must be specified or the plugin won't be loaded
* Contact gstreamer-devel@lists.sourceforge.net if your license should be
* added.
*
* GPL: http://www.gnu.org/copyleft/gpl.html
* LGPL: http://www.gnu.org/copyleft/lesser.html
* QPL: http://www.trolltech.com/licenses/qpl.html
*/
static gchar *valid_licenses[] = {
"LGPL", /* GNU Lesser General Public License */
"GPL", /* GNU General Public License */
"QPL", /* Trolltech Qt Public License */
"GPL/QPL", /* Combi-license of GPL + QPL */
GST_LICENSE_UNKNOWN, /* some other license */
NULL
};
static void gst_plugin_desc_copy (GstPluginDesc * dest,
const GstPluginDesc * src);
static GstPlugin *gst_plugin_register_func (GstPlugin * plugin,
GModule * module, GstPluginDesc * desc);
static GstPlugin *
gst_plugin_copy (GstPlugin * plugin)
{
return g_memdup (plugin, sizeof (*plugin));
}
GType
gst_plugin_get_type (void)
{
static GType plugin_type;
if (plugin_type == 0) {
plugin_type = g_boxed_type_register_static ("GstPlugin",
(GBoxedCopyFunc) gst_plugin_copy, g_free);
}
return plugin_type;
}
GQuark
gst_plugin_error_quark (void)
{
static GQuark quark = 0;
if (!quark)
quark = g_quark_from_static_string ("gst_plugin_error");
return quark;
}
/* this function can be called in the GCC constructor extension, before
* the _gst_plugin_initialize() was called. In that case, we store the
* plugin description in a list to initialize it when we open the main
* module later on.
* When the main module is known, we can register the plugin right away.
* */
void
_gst_plugin_register_static (GstPluginDesc * desc)
{
if (main_module == NULL) {
if (GST_CAT_DEFAULT)
GST_LOG ("queueing static plugin \"%s\" for loading later on",
desc->name);
_gst_plugin_static = g_list_prepend (_gst_plugin_static, desc);
} else {
GstPlugin *plugin;
if (GST_CAT_DEFAULT)
GST_LOG ("attempting to load static plugin \"%s\" now...", desc->name);
plugin = g_new0 (GstPlugin, 1);
if (gst_plugin_register_func (plugin, main_module, desc)) {
if (GST_CAT_DEFAULT)
GST_INFO ("loaded static plugin \"%s\"", desc->name);
gst_registry_pool_add_plugin (plugin);
}
}
}
void
_gst_plugin_initialize (void)
{
main_module = g_module_open (NULL, G_MODULE_BIND_LAZY);
/* now register all static plugins */
g_list_foreach (_gst_plugin_static, (GFunc) _gst_plugin_register_static,
NULL);
}
/* this function could be extended to check if the plugin license matches the
* applications license (would require the app to register its license somehow).
* We'll wait for someone who's interested in it to code it :)
*/
static gboolean
gst_plugin_check_license (const gchar * license)
{
gchar **check_license = valid_licenses;
g_assert (check_license);
while (*check_license) {
if (strcmp (license, *check_license) == 0)
return TRUE;
check_license++;
}
return FALSE;
}
static gboolean
gst_plugin_check_version (gint major, gint minor)
{
/* return NULL if the major and minor version numbers are not compatible */
/* with ours. */
if (major != GST_VERSION_MAJOR || minor != GST_VERSION_MINOR)
return FALSE;
return TRUE;
}
static GstPlugin *
gst_plugin_register_func (GstPlugin * plugin, GModule * module,
GstPluginDesc * desc)
{
g_assert (plugin->module == NULL);
if (!gst_plugin_check_version (desc->major_version, desc->minor_version)) {
if (GST_CAT_DEFAULT)
GST_INFO ("plugin \"%s\" has incompatible version, not loading",
plugin->filename);
return FALSE;
}
if (!desc->license || !desc->description || !desc->package || !desc->origin) {
if (GST_CAT_DEFAULT)
GST_INFO ("plugin \"%s\" has incorrect GstPluginDesc, not loading",
plugin->filename);
return FALSE;
}
if (!gst_plugin_check_license (desc->license)) {
if (GST_CAT_DEFAULT)
GST_INFO ("plugin \"%s\" has invalid license \"%s\", not loading",
plugin->filename, desc->license);
return FALSE;
}
if (GST_CAT_DEFAULT)
GST_LOG ("plugin \"%s\" looks good", GST_STR_NULL (plugin->filename));
gst_plugin_desc_copy (&plugin->desc, desc);
plugin->module = module;
if (!((desc->plugin_init) (plugin))) {
if (GST_CAT_DEFAULT)
GST_INFO ("plugin \"%s\" failed to initialise", plugin->filename);
plugin->module = NULL;
return FALSE;
}
if (GST_CAT_DEFAULT)
GST_LOG ("plugin \"%s\" initialised", GST_STR_NULL (plugin->filename));
return plugin;
}
#ifndef HAVE_WIN32
/*
* _gst_plugin_fault_handler_restore:
* segfault handler restorer
*/
static void
_gst_plugin_fault_handler_restore (void)
{
struct sigaction action;
memset (&action, 0, sizeof (action));
action.sa_handler = SIG_DFL;
sigaction (SIGSEGV, &action, NULL);
}
/*
* _gst_plugin_fault_handler_sighandler:
* segfault handler implementation
*/
static void
_gst_plugin_fault_handler_sighandler (int signum)
{
/* We need to restore the fault handler or we'll keep getting it */
_gst_plugin_fault_handler_restore ();
switch (signum) {
case SIGSEGV:
g_print ("\nERROR: ");
g_print ("Caught a segmentation fault while loading plugin file:\n");
g_print ("%s\n\n", _gst_plugin_fault_handler_filename);
g_print ("Please either:\n");
g_print ("- remove it and restart.\n");
g_print ("- run with --gst-disable-segtrap and debug.\n");
exit (-1);
break;
default:
g_print ("Caught unhandled signal on plugin loading\n");
break;
}
}
/*
* _gst_plugin_fault_handler_setup:
* sets up the segfault handler
*/
static void
_gst_plugin_fault_handler_setup (void)
{
struct sigaction action;
/* if asked to leave segfaults alone, just return */
if (_gst_disable_segtrap)
return;
if (_gst_plugin_fault_handler_is_setup)
return;
memset (&action, 0, sizeof (action));
action.sa_handler = _gst_plugin_fault_handler_sighandler;
sigaction (SIGSEGV, &action, NULL);
}
#else
static void
_gst_plugin_fault_handler_restore (void)
{
}
static void
_gst_plugin_fault_handler_setup (void)
{
}
#endif
static void _gst_plugin_fault_handler_setup ();
/**
* gst_plugin_check_file:
* @filename: the plugin filename to check for pluginness
* @error: pointer to a NULL-valued GError
*
* Checks if the given path represents a GStreamer plugin.
*
* Returns: TRUE if the given path is a GStreamer plugin.
*/
gboolean
gst_plugin_check_file (const gchar * filename, GError ** error)
{
GModule *module;
struct stat file_status;
gpointer ptr;
g_return_val_if_fail (filename != NULL, FALSE);
if (g_module_supported () == FALSE) {
g_set_error (error,
GST_PLUGIN_ERROR,
GST_PLUGIN_ERROR_MODULE, "Dynamic loading not supported");
return FALSE;
}
if (stat (filename, &file_status)) {
g_set_error (error,
GST_PLUGIN_ERROR,
GST_PLUGIN_ERROR_MODULE, "Problem accessing file %s: %s\n", filename,
strerror (errno));
return FALSE;
}
module = g_module_open (filename, G_MODULE_BIND_LAZY);
if (module == NULL) {
GST_DEBUG ("Error loading plugin %s, reason: %s\n", filename,
g_module_error ());
g_set_error (error, GST_PLUGIN_ERROR, GST_PLUGIN_ERROR_MODULE,
"Error loading plugin %s, reason: %s\n", filename, g_module_error ());
return FALSE;
}
if (!g_module_symbol (module, "gst_plugin_desc", &ptr)) {
GST_DEBUG ("Could not find plugin entry point in \"%s\"", filename);
g_set_error (error,
GST_PLUGIN_ERROR,
GST_PLUGIN_ERROR_MODULE,
"Could not find plugin entry point in \"%s\"", filename);
g_module_close (module);
return FALSE;
}
/* it's a plugin */
GST_INFO ("looks like a gst plugin \"%s\"", filename);
g_module_close (module);
return TRUE;
}
/**
* gst_plugin_load_file:
* @filename: the plugin filename to load
* @error: pointer to a NULL-valued GError
*
* Loads the given plugin.
*
* Returns: a new GstPlugin or NULL, if an error occurred.
*/
GstPlugin *
gst_plugin_load_file (const gchar * filename, GError ** error)
{
GstPlugin *plugin;
GModule *module;
GstPluginDesc *desc;
gboolean free_plugin;
gpointer ptr;
g_return_val_if_fail (filename != NULL, NULL);
GST_CAT_DEBUG (GST_CAT_PLUGIN_LOADING, "attempt to load plugin \"%s\"",
filename);
if (!gst_plugin_check_file (filename, error))
return NULL;
module = g_module_open (filename, G_MODULE_BIND_LAZY);
if (module == NULL)
goto load_error;
if (!g_module_symbol (module, "gst_plugin_desc", &ptr))
goto load_error;
desc = (GstPluginDesc *) ptr;
plugin = gst_registry_pool_find_plugin (desc->name);
if (!plugin) {
free_plugin = TRUE;
plugin = g_new0 (GstPlugin, 1);
plugin->filename = g_strdup (filename);
GST_DEBUG ("created new GstPlugin %p for file \"%s\"", plugin, filename);
} else {
free_plugin = FALSE;
if (gst_plugin_is_loaded (plugin)) {
if (plugin->filename && strcmp (plugin->filename, filename) != 0) {
GST_WARNING
("plugin %p from file \"%s\" with same name %s is already "
"loaded, aborting loading of \"%s\"", plugin, plugin->filename,
plugin->desc.name, filename);
g_set_error (error, GST_PLUGIN_ERROR,
GST_PLUGIN_ERROR_NAME_MISMATCH,
"plugin %p from file \"%s\" with same name %s is already "
"loaded, aborting loading of \"%s\"", plugin, plugin->filename,
plugin->desc.name, filename);
if (free_plugin)
g_free (plugin);
return NULL;
}
GST_LOG ("Plugin %p for file \"%s\" already loaded, returning it now",
plugin, filename);
return plugin;
}
}
GST_LOG ("Plugin %p for file \"%s\" prepared, calling entry function...",
plugin, filename);
if (g_module_symbol (module, "plugin_init", &ptr)) {
GST_WARNING
("plugin %p from file \"%s\" exports a symbol named plugin_init\n",
plugin, plugin->filename);
g_set_error (error, GST_PLUGIN_ERROR, GST_PLUGIN_ERROR_NAME_MISMATCH,
"plugin \"%s\" exports a symbol named plugin_init", desc->name);
}
/* this is where we load the actual .so, so let's trap SIGSEGV */
_gst_plugin_fault_handler_setup ();
_gst_plugin_fault_handler_filename = plugin->filename;
GST_LOG ("Plugin %p for file \"%s\" prepared, registering...",
plugin, filename);
if (gst_plugin_register_func (plugin, module, desc)) {
/* remove signal handler */
_gst_plugin_fault_handler_restore ();
_gst_plugin_fault_handler_filename = NULL;
GST_INFO ("plugin \"%s\" loaded", plugin->filename);
return plugin;
} else {
/* remove signal handler */
_gst_plugin_fault_handler_restore ();
GST_DEBUG ("gst_plugin_register_func failed for plugin \"%s\"", filename);
/* plugin == NULL */
g_set_error (error,
GST_PLUGIN_ERROR,
GST_PLUGIN_ERROR_MODULE,
"gst_plugin_register_func failed for plugin \"%s\"", filename);
if (free_plugin)
g_free (plugin);
return NULL;
}
load_error:
g_set_error (error,
GST_PLUGIN_ERROR,
GST_PLUGIN_ERROR_MODULE, "generic load error for \"%s\"", filename);
return NULL;
}
static void
gst_plugin_desc_copy (GstPluginDesc * dest, const GstPluginDesc * src)
{
dest->major_version = src->major_version;
dest->minor_version = src->minor_version;
g_free (dest->name);
dest->name = g_strdup (src->name);
g_free (dest->description);
dest->description = g_strdup (src->description);
dest->plugin_init = src->plugin_init;
dest->plugin_exit = src->plugin_exit;
g_free (dest->version);
dest->version = g_strdup (src->version);
g_free (dest->license);
dest->license = g_strdup (src->license);
g_free (dest->package);
dest->package = g_strdup (src->package);
g_free (dest->origin);
dest->origin = g_strdup (src->origin);
}
#if 0
/* unused */
static void
gst_plugin_desc_free (GstPluginDesc * desc)
{
g_free (desc->name);
g_free (desc->description);
g_free (desc->version);
g_free (desc->license);
g_free (desc->package);
g_free (desc->origin);
memset (desc, 0, sizeof (GstPluginDesc));
}
#endif
/**
* gst_plugin_unload_plugin:
* @plugin: The plugin to unload
*
* Unload the given plugin.
*
* Returns: whether or not the plugin unloaded
*/
gboolean
gst_plugin_unload_plugin (GstPlugin * plugin)
{
g_return_val_if_fail (plugin != NULL, FALSE);
if (!plugin->module)
return TRUE;
if (g_module_close (plugin->module)) {
plugin->module = NULL;
GST_CAT_INFO (GST_CAT_PLUGIN_LOADING, "plugin \"%s\" unloaded",
plugin->filename);
return TRUE;
} else {
GST_CAT_INFO (GST_CAT_PLUGIN_LOADING, "failed to unload plugin \"%s\"",
plugin->filename);
return FALSE;
}
}
/**
* 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->desc.name;
}
/**
* gst_plugin_get_description:
* @plugin: plugin to get long name of
*
* Get the long descriptive name of the plugin
*
* Returns: the long name of the plugin
*/
G_CONST_RETURN gchar *
gst_plugin_get_description (GstPlugin * plugin)
{
g_return_val_if_fail (plugin != NULL, NULL);
return plugin->desc.description;
}
/**
* gst_plugin_get_filename:
* @plugin: plugin to get the filename of
*
* get the filename of the plugin
*
* Returns: the filename of the plugin
*/
G_CONST_RETURN gchar *
gst_plugin_get_filename (GstPlugin * plugin)
{
g_return_val_if_fail (plugin != NULL, NULL);
return plugin->filename;
}
/**
* gst_plugin_get_license:
* @plugin: plugin to get the license of
*
* get the license of the plugin
*
* Returns: the license of the plugin
*/
G_CONST_RETURN gchar *
gst_plugin_get_license (GstPlugin * plugin)
{
g_return_val_if_fail (plugin != NULL, NULL);
return plugin->desc.license;
}
/**
* gst_plugin_get_package:
* @plugin: plugin to get the package of
*
* get the package the plugin belongs to.
*
* Returns: the package of the plugin
*/
G_CONST_RETURN gchar *
gst_plugin_get_package (GstPlugin * plugin)
{
g_return_val_if_fail (plugin != NULL, NULL);
return plugin->desc.package;
}
/**
* gst_plugin_get_origin:
* @plugin: plugin to get the origin of
*
* get the URL where the plugin comes from
*
* Returns: the origin of the plugin
*/
G_CONST_RETURN gchar *
gst_plugin_get_origin (GstPlugin * plugin)
{
g_return_val_if_fail (plugin != NULL, NULL);
return plugin->desc.origin;
}
/**
* gst_plugin_get_module:
* @plugin: plugin to query
*
* Gets the #GModule of the plugin. If the plugin isn't loaded yet, NULL is
* returned.
*
* Returns: module belonging to the plugin or NULL if the plugin isn't
* loaded yet.
*/
GModule *
gst_plugin_get_module (GstPlugin * plugin)
{
g_return_val_if_fail (plugin != NULL, FALSE);
return plugin->module;
}
/**
* 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->module != NULL);
}
/**
* gst_plugin_feature_list:
* @plugin: plugin to query
* @filter: the filter to use
* @first: only return first match
* @user_data: user data passed to the filter function
*
* Runs a filter against all plugin features and returns a GList with
* the results. If the first flag is set, only the first match is
* returned (as a list with a single object).
*
* Returns: a GList of features, g_list_free after use.
*/
GList *
gst_plugin_feature_filter (GstPlugin * plugin,
GstPluginFeatureFilter filter, gboolean first, gpointer user_data)
{
return gst_filter_run (plugin->features, (GstFilterFunc) filter, first,
user_data);
}
typedef struct
{
GstPluginFeatureFilter filter;
gboolean first;
gpointer user_data;
GList *result;
}
FeatureFilterData;
static gboolean
_feature_filter (GstPlugin * plugin, gpointer user_data)
{
GList *result;
FeatureFilterData *data = (FeatureFilterData *) user_data;
result =
gst_plugin_feature_filter (plugin, data->filter, data->first,
data->user_data);
if (result) {
data->result = g_list_concat (data->result, result);
return TRUE;
}
return FALSE;
}
/**
* gst_plugin_list_feature_list:
* @list: a list of plugins to query
* @filter: the filter to use
* @first: only return first match
* @user_data: user data passed to the filter function
*
* Runs a filter against all plugin features of the plugins in the given
* list and returns a GList with the results.
* If the first flag is set, only the first match is
* returned (as a list with a single object).
*
* Returns: a GList of features, g_list_free after use.
*/
GList *
gst_plugin_list_feature_filter (GList * list,
GstPluginFeatureFilter filter, gboolean first, gpointer user_data)
{
FeatureFilterData data;
GList *result;
data.filter = filter;
data.first = first;
data.user_data = user_data;
data.result = NULL;
result = gst_filter_run (list, (GstFilterFunc) _feature_filter, first, &data);
g_list_free (result);
return data.result;
}
/**
* gst_plugin_name_filter:
* @plugin: the plugin to check
* @name: the name of the plugin
*
* A standard filter that returns TRUE when the plugin is of the
* given name.
*
* Returns: TRUE if the plugin is of the given name.
*/
gboolean
gst_plugin_name_filter (GstPlugin * plugin, const gchar * name)
{
return (plugin->desc.name && !strcmp (plugin->desc.name, name));
}
/**
* gst_plugin_find_feature:
* @plugin: plugin to get the feature from
* @name: The name of the feature to find
* @type: The type of the feature to find
*
* Find a feature of the given name and type in the given plugin.
*
* Returns: a GstPluginFeature or NULL if the feature was not found.
*/
GstPluginFeature *
gst_plugin_find_feature (GstPlugin * plugin, const gchar * name, GType type)
{
GList *walk;
GstPluginFeature *result = NULL;
GstTypeNameData data;
g_return_val_if_fail (name != NULL, NULL);
data.type = type;
data.name = name;
walk = gst_filter_run (plugin->features,
(GstFilterFunc) gst_plugin_feature_type_name_filter, TRUE, &data);
if (walk)
result = GST_PLUGIN_FEATURE (walk->data);
return result;
}
/**
* gst_plugin_add_feature:
* @plugin: plugin to add feature to
* @feature: feature to add
*
* Add feature to the list of those provided by the plugin.
* There is a separate namespace for each plugin feature type.
* See #gst_plugin_get_feature_list
*/
void
gst_plugin_add_feature (GstPlugin * plugin, GstPluginFeature * feature)
{
GstPluginFeature *oldfeature;
/* FIXME 0.9: get reference counting somewhat right in here,
* GstPluginFeatures should probably be GstObjects that are sinked when
* adding them to a plugin */
g_return_if_fail (plugin != NULL);
g_return_if_fail (GST_IS_PLUGIN_FEATURE (feature));
g_return_if_fail (feature != NULL);
oldfeature = gst_plugin_find_feature (plugin,
GST_PLUGIN_FEATURE_NAME (feature), G_OBJECT_TYPE (feature));
if (oldfeature == feature) {
GST_WARNING ("feature %s has already been added",
GST_PLUGIN_FEATURE_NAME (feature));
/* g_object_unref (feature); */
} else if (oldfeature) {
GST_WARNING ("feature %s already present in plugin",
GST_PLUGIN_FEATURE_NAME (feature));
/* g_object_unref (feature); */
} else {
feature->manager = plugin;
plugin->features = g_list_prepend (plugin->features, feature);
plugin->numfeatures++;
}
}
/**
* gst_plugin_get_feature_list:
* @plugin: the plugin to get the features from
*
* get a list of all the features that this plugin provides
*
* Returns: a GList of features, use g_list_free to free the list.
*/
GList *
gst_plugin_get_feature_list (GstPlugin * plugin)
{
g_return_val_if_fail (plugin != NULL, NULL);
return g_list_copy (plugin->features);
}
/**
* gst_plugin_load:
* @name: name of plugin to load
*
* Load the named plugin.
*
* Returns: whether the plugin was loaded or not
*/
gboolean
gst_plugin_load (const gchar * name)
{
GstPlugin *plugin;
GError *error = NULL;
plugin = gst_registry_pool_find_plugin (name);
if (plugin) {
gst_plugin_load_file (plugin->filename, &error);
if (error) {
GST_WARNING ("load_plugin error: %s\n", error->message);
g_error_free (error);
return FALSE;
}
return TRUE;;
}
GST_DEBUG ("Could not find %s in registry pool", name);
return FALSE;
}
/**
* 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;
/* for now this is the same */
res = gst_plugin_load (name);
return res;
}