gstreamer/gst/gstpluginfeature.c
Seungha Yang 52706146f5 pluginfeature: Allow updating initial rank of plugin feature
Introducing "GST_PLUGIN_FEATURE_RANK" environment variable in order for users
to adjust rank of plugin(s) via environment.

A "feature" and "rank" key-value pair should be separable by ":",
and each key-value pair is recognized per "," delimiters. The rank
can be a numerical value or one of pre-defined rank values
such as "NONE", "MARGINAL", "SECONDARY", and "PRIMARY" in case-insensitive manner.

In addition to pre-defined { NONE, MARGINAL, SECONDARY, PRIMARY },
"MAX" can be passed to key value used to ensure having a higher rank
than other plugin features.

Example)
- GST_PLUGIN_FEATURE_RANK=qtdemux:256,h264parse:NONE
Set rank of qtdemux plugin to 256 (primary) and 0 (none) for h264parse.
2019-12-26 19:49:00 +00:00

501 lines
13 KiB
C

/* GStreamer
* Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
* 2000 Wim Taymans <wtay@chello.be>
*
* gstpluginfeature.c: Abstract base class for all plugin features
*
* 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., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
/**
* SECTION:gstpluginfeature
* @title: GstPluginfeature
* @short_description: Base class for contents of a GstPlugin
* @see_also: #GstPlugin
*
* This is a base class for anything that can be added to a #GstPlugin.
*/
#include "gst_private.h"
#include "gstpluginfeature.h"
#include "gstplugin.h"
#include "gstregistry.h"
#include "gstinfo.h"
#include <stdio.h>
#include <string.h>
#define GST_CAT_DEFAULT GST_CAT_PLUGIN_LOADING
static void gst_plugin_feature_finalize (GObject * object);
/* static guint gst_plugin_feature_signals[LAST_SIGNAL] = { 0 }; */
G_DEFINE_ABSTRACT_TYPE (GstPluginFeature, gst_plugin_feature, GST_TYPE_OBJECT);
static void
gst_plugin_feature_class_init (GstPluginFeatureClass * klass)
{
G_OBJECT_CLASS (klass)->finalize = gst_plugin_feature_finalize;
}
static void
gst_plugin_feature_init (GstPluginFeature * feature)
{
/* do nothing, needed because of G_DEFINE_TYPE */
}
static void
gst_plugin_feature_finalize (GObject * object)
{
GstPluginFeature *feature = GST_PLUGIN_FEATURE_CAST (object);
GST_DEBUG ("finalizing feature %p: '%s'", feature, GST_OBJECT_NAME (feature));
if (feature->plugin != NULL) {
g_object_remove_weak_pointer ((GObject *) feature->plugin,
(gpointer *) & feature->plugin);
}
G_OBJECT_CLASS (gst_plugin_feature_parent_class)->finalize (object);
}
/**
* gst_plugin_feature_load:
* @feature: (transfer none): the plugin feature to check
*
* Loads the plugin containing @feature if it's not already loaded. @feature is
* unaffected; use the return value instead.
*
* Normally this function is used like this:
* |[<!-- language="C" -->
* GstPluginFeature *loaded_feature;
*
* loaded_feature = gst_plugin_feature_load (feature);
* // presumably, we're no longer interested in the potentially-unloaded feature
* gst_object_unref (feature);
* feature = loaded_feature;
* ]|
*
* Returns: (transfer full) (nullable): a reference to the loaded
* feature, or %NULL on error
*/
GstPluginFeature *
gst_plugin_feature_load (GstPluginFeature * feature)
{
GstPlugin *plugin;
GstPluginFeature *real_feature;
g_return_val_if_fail (feature != NULL, FALSE);
g_return_val_if_fail (GST_IS_PLUGIN_FEATURE (feature), FALSE);
GST_DEBUG ("loading plugin for feature %p; '%s'", feature,
GST_OBJECT_NAME (feature));
if (feature->loaded)
return gst_object_ref (feature);
GST_DEBUG ("loading plugin %s", feature->plugin_name);
plugin = gst_plugin_load_by_name (feature->plugin_name);
if (!plugin)
goto load_failed;
GST_DEBUG ("loaded plugin %s", feature->plugin_name);
gst_object_unref (plugin);
real_feature = gst_registry_lookup_feature (gst_registry_get (),
GST_OBJECT_NAME (feature));
if (real_feature == NULL)
goto disappeared;
else if (!real_feature->loaded)
goto not_found;
return real_feature;
/* ERRORS */
load_failed:
{
GST_WARNING ("Failed to load plugin containing feature '%s'.",
GST_OBJECT_NAME (feature));
return NULL;
}
disappeared:
{
GST_INFO
("Loaded plugin containing feature '%s', but feature disappeared.",
GST_OBJECT_NAME (feature));
return NULL;
}
not_found:
{
GST_INFO ("Tried to load plugin containing feature '%s', but feature was "
"not found.", GST_OBJECT_NAME (real_feature));
return NULL;
}
}
/**
* gst_plugin_feature_set_rank:
* @feature: feature to rank
* @rank: rank value - higher number means more priority rank
*
* Specifies a rank for a plugin feature, so that autoplugging uses
* the most appropriate feature.
*/
void
gst_plugin_feature_set_rank (GstPluginFeature * feature, guint rank)
{
g_return_if_fail (feature != NULL);
g_return_if_fail (GST_IS_PLUGIN_FEATURE (feature));
feature->rank = rank;
}
/**
* gst_plugin_feature_get_rank:
* @feature: a feature
*
* Gets the rank of a plugin feature.
*
* Returns: The rank of the feature
*/
guint
gst_plugin_feature_get_rank (GstPluginFeature * feature)
{
g_return_val_if_fail (GST_IS_PLUGIN_FEATURE (feature), GST_RANK_NONE);
return feature->rank;
}
/**
* gst_plugin_feature_get_plugin:
* @feature: a feature
*
* Get the plugin that provides this feature.
*
* Returns: (transfer full) (nullable): the plugin that provides this
* feature, or %NULL. Unref with gst_object_unref() when no
* longer needed.
*/
GstPlugin *
gst_plugin_feature_get_plugin (GstPluginFeature * feature)
{
g_return_val_if_fail (GST_IS_PLUGIN_FEATURE (feature), NULL);
if (feature->plugin == NULL)
return NULL;
return (GstPlugin *) gst_object_ref (feature->plugin);
}
/**
* gst_plugin_feature_get_plugin_name:
* @feature: a feature
*
* Get the name of the plugin that provides this feature.
*
* Returns: (nullable): the name of the plugin that provides this
* feature, or %NULL if the feature is not associated with a
* plugin.
*
* Since: 1.2
*/
const gchar *
gst_plugin_feature_get_plugin_name (GstPluginFeature * feature)
{
g_return_val_if_fail (GST_IS_PLUGIN_FEATURE (feature), NULL);
if (feature->plugin == NULL)
return NULL;
return gst_plugin_get_name (feature->plugin);
}
/**
* gst_plugin_feature_list_free:
* @list: (transfer full) (element-type Gst.PluginFeature): list
* of #GstPluginFeature
*
* Unrefs each member of @list, then frees the list.
*/
void
gst_plugin_feature_list_free (GList * list)
{
GList *g;
for (g = list; g; g = g->next) {
GstPluginFeature *feature = GST_PLUGIN_FEATURE_CAST (g->data);
gst_object_unref (feature);
}
g_list_free (list);
}
/**
* gst_plugin_feature_list_copy:
* @list: (transfer none) (element-type Gst.PluginFeature): list
* of #GstPluginFeature
*
* Copies the list of features. Caller should call @gst_plugin_feature_list_free
* when done with the list.
*
* Returns: (transfer full) (element-type Gst.PluginFeature): a copy of @list,
* with each feature's reference count incremented.
*/
GList *
gst_plugin_feature_list_copy (GList * list)
{
GList *new_list = NULL;
if (G_LIKELY (list)) {
GList *last;
new_list = g_list_alloc ();
new_list->data = gst_object_ref (list->data);
new_list->prev = NULL;
last = new_list;
list = list->next;
while (list) {
last->next = g_list_alloc ();
last->next->prev = last;
last = last->next;
last->data = gst_object_ref (list->data);
list = list->next;
}
last->next = NULL;
}
return new_list;
}
/**
* gst_plugin_feature_list_debug:
* @list: (transfer none) (element-type Gst.PluginFeature): a #GList of
* plugin features
*
* Debug the plugin feature names in @list.
*/
void
gst_plugin_feature_list_debug (GList * list)
{
#ifndef GST_DISABLE_GST_DEBUG
while (list) {
GST_DEBUG ("%s",
gst_plugin_feature_get_name ((GstPluginFeature *) list->data));
list = list->next;
}
#endif
}
/**
* gst_plugin_feature_check_version:
* @feature: a feature
* @min_major: minimum required major version
* @min_minor: minimum required minor version
* @min_micro: minimum required micro version
*
* Checks whether the given plugin feature is at least
* the required version
*
* Returns: %TRUE if the plugin feature has at least
* the required version, otherwise %FALSE.
*/
gboolean
gst_plugin_feature_check_version (GstPluginFeature * feature,
guint min_major, guint min_minor, guint min_micro)
{
GstRegistry *registry;
GstPlugin *plugin;
gboolean ret = FALSE;
g_return_val_if_fail (feature != NULL, FALSE);
g_return_val_if_fail (GST_IS_PLUGIN_FEATURE (feature), FALSE);
GST_DEBUG ("Looking up plugin '%s' containing plugin feature '%s'",
feature->plugin_name, GST_OBJECT_NAME (feature));
registry = gst_registry_get ();
plugin = gst_registry_find_plugin (registry, feature->plugin_name);
if (plugin) {
const gchar *ver_str;
guint major, minor, micro, nano;
gint nscan;
ver_str = gst_plugin_get_version (plugin);
g_return_val_if_fail (ver_str != NULL, FALSE);
nscan = sscanf (ver_str, "%u.%u.%u.%u", &major, &minor, &micro, &nano);
GST_DEBUG ("version string '%s' parsed to %d values", ver_str, nscan);
if (nscan >= 3) {
if (major > min_major)
ret = TRUE;
else if (major < min_major)
ret = FALSE;
else if (minor > min_minor)
ret = TRUE;
else if (minor < min_minor)
ret = FALSE;
else if (micro > min_micro)
ret = TRUE;
/* micro is 1 smaller but we have a nano version, this is the upcoming
* release of the requested version and we're ok then */
else if (nscan == 4 && nano > 0 && (micro + 1 == min_micro))
ret = TRUE;
else
ret = (micro == min_micro);
GST_DEBUG ("Checking whether %u.%u.%u >= %u.%u.%u? %s", major, minor,
micro, min_major, min_minor, min_micro, (ret) ? "yes" : "no");
} else {
GST_WARNING ("Could not parse version string '%s' of plugin '%s'",
ver_str, feature->plugin_name);
}
gst_object_unref (plugin);
} else {
GST_DEBUG ("Could not find plugin '%s'", feature->plugin_name);
}
return ret;
}
/**
* gst_plugin_feature_rank_compare_func:
* @p1: a #GstPluginFeature
* @p2: a #GstPluginFeature
*
* Compares the two given #GstPluginFeature instances. This function can be
* used as a #GCompareFunc when sorting by rank and then by name.
*
* Returns: negative value if the rank of p1 > the rank of p2 or the ranks are
* equal but the name of p1 comes before the name of p2; zero if the rank
* and names are equal; positive value if the rank of p1 < the rank of p2 or the
* ranks are equal but the name of p2 comes before the name of p1
*/
gint
gst_plugin_feature_rank_compare_func (gconstpointer p1, gconstpointer p2)
{
GstPluginFeature *f1, *f2;
gint diff;
f1 = (GstPluginFeature *) p1;
f2 = (GstPluginFeature *) p2;
diff = f2->rank - f1->rank;
if (diff != 0)
return diff;
diff = strcmp (GST_OBJECT_NAME (f1), GST_OBJECT_NAME (f2));
return diff;
}
static gboolean
parse_feature_name (gchar * str, const gchar ** feature)
{
if (!str)
return FALSE;
/* works in place */
g_strstrip (str);
if (str[0] != '\0') {
*feature = str;
return TRUE;
}
return FALSE;
}
static gboolean
parse_feature_rank (gchar * str, GstRank * rank)
{
if (!str)
return FALSE;
/* works in place */
g_strstrip (str);
if (g_ascii_isdigit (str[0])) {
unsigned long l;
char *endptr;
l = strtoul (str, &endptr, 10);
if (endptr > str && endptr[0] == 0) {
*rank = (GstRank) l;
} else {
return FALSE;
}
} else if (g_ascii_strcasecmp (str, "NONE") == 0) {
*rank = GST_RANK_NONE;
} else if (g_ascii_strcasecmp (str, "MARGINAL") == 0) {
*rank = GST_RANK_MARGINAL;
} else if (g_ascii_strcasecmp (str, "SECONDARY") == 0) {
*rank = GST_RANK_SECONDARY;
} else if (g_ascii_strcasecmp (str, "PRIMARY") == 0) {
*rank = GST_RANK_PRIMARY;
} else if (g_ascii_strcasecmp (str, "MAX") == 0) {
*rank = (GstRank) G_MAXINT;
} else {
return FALSE;
}
return TRUE;
}
void
_priv_gst_plugin_feature_rank_initialize (void)
{
const gchar *env;
gchar **split;
gchar **walk;
env = g_getenv ("GST_PLUGIN_FEATURE_RANK");
if (!env)
return;
split = g_strsplit (env, ",", 0);
for (walk = split; *walk; walk++) {
if (strchr (*walk, ':')) {
gchar **values = g_strsplit (*walk, ":", 2);
if (values[0] && values[1]) {
GstRank rank;
const gchar *str;
if (parse_feature_name (values[0], &str)
&& parse_feature_rank (values[1], &rank)) {
GstPluginFeature *feature;
feature = gst_registry_find_feature (gst_registry_get (), str,
GST_TYPE_ELEMENT_FACTORY);
if (feature) {
gst_plugin_feature_set_rank (feature, rank);
GST_DEBUG ("Update rank of plugin feature \"%s\" to %d", str, rank);
}
}
}
g_strfreev (values);
}
}
g_strfreev (split);
}