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Original commit message from CVS: First THREADED backport attempt, focusing on adding locks and making sure the API is threadsafe. Needs more work. More docs follow this week.
440 lines
13 KiB
C
440 lines
13 KiB
C
/* GStreamer
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* Copyright (C) 1999-2002 Erik Walthinsen <omega@cse.ogi.edu>
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* 2000-2002 Wim Taymans <wtay@chello.be>
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*
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* gstsearchfuncs.c: functions needed when doing searches while
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* autoplugging
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*/
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif
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#include "gstsearchfuncs.h"
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/* FIXME: "evil hack" alarm, we need a better way to get a category in here */
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GST_DEBUG_CATEGORY_EXTERN (GST_CAT_AUTOPLUG_ATTEMPT);
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#define GST_CAT_DEFAULT GST_CAT_AUTOPLUG_ATTEMPT
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/* function that really misses in GLib
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* though the GLib version should take a function as argument...
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*/
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static void
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g_list_free_list_and_elements (GList * list)
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{
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GList *walk = list;
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while (walk) {
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g_free (walk->data);
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walk = g_list_next (walk);
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}
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g_list_free (list);
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}
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/**
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* gst_autoplug_caps_intersect:
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* @src: a source #GstCaps
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* @sink: the sink #GstCaps
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*
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* Checks if the given caps have a non-null intersection.
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*
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* Returns: TRUE, if both caps intersect.
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*/
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gboolean
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gst_autoplug_caps_intersect (const GstCaps * src, const GstCaps * sink)
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{
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GstCaps *caps;
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/* get an intersection */
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caps = gst_caps_intersect (src, sink);
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/* if the caps can't link, there is no intersection */
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if (gst_caps_is_empty (caps)) {
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gst_caps_unref (caps);
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return FALSE;
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}
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/* hurrah, we can link, now remove the intersection */
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gst_caps_unref (caps);
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return TRUE;
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}
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/**
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* gst_autoplug_can_connect_src:
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* @fac: factory to connect to
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* @src: caps to check
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*
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* Checks if a factory's sink can connect to the given caps
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*
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* Returns: #GstPadTemplate that can connect to the given caps
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*/
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GstPadTemplate *
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gst_autoplug_can_connect_src (GstElementFactory * fac, const GstCaps * src)
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{
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GList *templs;
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templs = fac->padtemplates;
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while (templs) {
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if ((GST_PAD_TEMPLATE_DIRECTION (templs->data) == GST_PAD_SINK) &&
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gst_autoplug_caps_intersect (src,
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GST_PAD_TEMPLATE_CAPS (templs->data))) {
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return GST_PAD_TEMPLATE (templs->data);
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}
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templs = g_list_next (templs);
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}
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return NULL;
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}
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/**
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* gst_autoplug_can_connect_sink:
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* @fac: factory to connect to
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* @sink: caps to check
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*
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* Checks if a factory's src can connect to the given caps
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*
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* Returns: #GstPadTemplate that can connect to the given caps
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*/
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GstPadTemplate *
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gst_autoplug_can_connect_sink (GstElementFactory * fac, const GstCaps * sink)
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{
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GList *templs;
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templs = fac->padtemplates;
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while (templs) {
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GstCaps *caps = GST_PAD_TEMPLATE_CAPS (templs->data);
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if ((GST_PAD_TEMPLATE_DIRECTION (templs->data) == GST_PAD_SRC) &&
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gst_autoplug_caps_intersect (caps, sink)) {
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return GST_PAD_TEMPLATE (templs->data);
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}
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templs = g_list_next (templs);
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}
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return NULL;
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}
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GstPadTemplate *
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gst_autoplug_can_match (GstElementFactory * src, GstElementFactory * dest)
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{
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GList *srctemps, *desttemps;
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srctemps = src->padtemplates;
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while (srctemps) {
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GstPadTemplate *srctemp = (GstPadTemplate *) srctemps->data;
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desttemps = dest->padtemplates;
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while (desttemps) {
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GstPadTemplate *desttemp = (GstPadTemplate *) desttemps->data;
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if (srctemp->direction == GST_PAD_SRC &&
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desttemp->direction == GST_PAD_SINK) {
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if (gst_autoplug_caps_intersect (gst_pad_template_get_caps (srctemp),
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gst_pad_template_get_caps (desttemp))) {
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GST_DEBUG ("factory \"%s\" can connect with factory \"%s\"",
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GST_OBJECT_NAME (src), GST_OBJECT_NAME (dest));
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return desttemp;
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}
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}
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desttemps = g_list_next (desttemps);
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}
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srctemps = g_list_next (srctemps);
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}
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GST_DEBUG ("factory \"%s\" cannot connect with factory \"%s\"",
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GST_OBJECT_NAME (src), GST_OBJECT_NAME (dest));
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return NULL;
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}
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/* returns TRUE if the factory has padtemplates with the specified direction */
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gboolean
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gst_autoplug_factory_has_direction (GstElementFactory * fac,
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GstPadDirection dir)
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{
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GList *templs = fac->padtemplates;
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while (templs) {
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if (GST_PAD_TEMPLATE_DIRECTION (templs->data) == dir) {
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return TRUE;
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}
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templs = g_list_next (templs);
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}
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return FALSE;
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}
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/* Decisions are based on the padtemplates.
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* These functions return a new list so be sure to free it.
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*/
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GList *
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gst_autoplug_factories_sinks (GList * factories)
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{
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GList *ret = NULL;
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while (factories) {
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if (gst_autoplug_factory_has_sink (factories->data))
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ret = g_list_prepend (ret, factories->data);
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factories = g_list_next (factories);
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}
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return ret;
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}
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GList *
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gst_autoplug_factories_srcs (GList * factories)
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{
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GList *ret = NULL;
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while (factories) {
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if (gst_autoplug_factory_has_src (factories->data))
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ret = g_list_prepend (ret, factories->data);
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factories = g_list_next (factories);
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}
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return ret;
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}
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GList *
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gst_autoplug_factories_filters (GList * factories)
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{
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GList *ret = NULL;
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while (factories) {
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/* if you want it faster do src/sink check at once, don't call two functions */
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if (gst_autoplug_factory_has_src (factories->data)
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&& gst_autoplug_factory_has_sink (factories->data))
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ret = g_list_prepend (ret, factories->data);
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factories = g_list_next (factories);
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}
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return ret;
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}
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static gint
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gst_autoplug_rank_compare (const GstElementFactory * a,
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const GstElementFactory * b)
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{
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if (GST_PLUGIN_FEATURE (a)->rank > GST_PLUGIN_FEATURE (b)->rank)
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return -1;
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return (GST_PLUGIN_FEATURE (a)->rank < GST_PLUGIN_FEATURE (b)->rank) ? 1 : 0;
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}
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/* returns all factories which have sinks with non-NULL caps and srcs with
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* any caps. also only returns factories with a non-zero rank, and sorts by
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* rank descending.
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*/
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GList *
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gst_autoplug_factories_filters_with_sink_caps (GList * factories)
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{
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GList *ret = NULL;
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GstElementFactory *factory;
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GList *templs;
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while (factories) {
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factory = (GstElementFactory *) factories->data;
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templs = factory->padtemplates;
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if (GST_PLUGIN_FEATURE (factory)->rank > 0) {
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gboolean have_src = FALSE;
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gboolean have_sink = FALSE;
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while (templs) {
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if (GST_PAD_TEMPLATE_DIRECTION (templs->data) == GST_PAD_SRC) {
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have_src = TRUE;
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}
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if ((GST_PAD_TEMPLATE_DIRECTION (templs->data) == GST_PAD_SINK)
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&& (GST_PAD_TEMPLATE_CAPS (templs->data) != NULL)) {
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have_sink = TRUE;
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}
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if (have_src && have_sink) {
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ret = g_list_prepend (ret, factory);
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break;
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}
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templs = g_list_next (templs);
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}
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}
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factories = g_list_next (factories);
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}
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return g_list_sort (ret, (GCompareFunc) gst_autoplug_rank_compare);
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}
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/* returns all factories which have a maximum of maxtemplates GstPadTemplates in direction dir
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*/
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GList *
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gst_autoplug_factories_at_most_templates (GList * factories,
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GstPadDirection dir, guint maxtemplates)
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{
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GList *ret = NULL;
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while (factories) {
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guint count = 0;
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GList *templs = ((GstElementFactory *) factories->data)->padtemplates;
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while (templs) {
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if (GST_PAD_TEMPLATE_DIRECTION (templs->data) == dir) {
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count++;
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}
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if (count > maxtemplates)
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break;
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templs = g_list_next (templs);
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}
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if (count <= maxtemplates)
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ret = g_list_prepend (ret, factories->data);
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factories = g_list_next (factories);
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}
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return ret;
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}
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/*********************************************************************
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*
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* SHORTEST PATH ALGORITHM
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*/
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/**
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* gst_autoplug_sp:
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* @src_caps: a #GstCaps to plug from.
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* @sink_caps: the #GstCaps to plug to.
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* @factories: a #GList containing all allowed #GstElementFactory entries.
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*
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* Finds the shortest path of elements that together make up a possible
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* connection between the source and sink caps.
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*
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* Returns: a #GList of #GstElementFactory items which have to be connected
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* to get the shortest path.
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*/
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GList *
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gst_autoplug_sp (const GstCaps * srccaps, const GstCaps * sinkcaps,
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GList * factories)
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{
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GList *factory_nodes = NULL;
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guint curcost = GST_AUTOPLUG_MAX_COST; /* below this cost, there is no path */
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GstAutoplugNode *bestnode = NULL; /* best (unconnected) endpoint currently */
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g_return_val_if_fail (srccaps != NULL, NULL);
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g_return_val_if_fail (sinkcaps != NULL, NULL);
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GST_INFO ("attempting to autoplug via shortest path from %"
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GST_PTR_FORMAT " to %" GST_PTR_FORMAT, srccaps, sinkcaps);
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/* wrap all factories as GstAutoplugNode
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* initialize the cost */
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while (factories) {
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GstAutoplugNode *node = g_new0 (GstAutoplugNode, 1);
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node->prev = NULL;
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node->fac = (GstElementFactory *) factories->data;
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GST_DEBUG ("trying with %s", node->fac->details.longname);
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node->templ = gst_autoplug_can_connect_src (node->fac, srccaps);
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node->cost = (node->templ ? gst_autoplug_get_cost (node->fac)
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: GST_AUTOPLUG_MAX_COST);
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node->endpoint = gst_autoplug_can_connect_sink (node->fac, sinkcaps);
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if (node->templ && node->endpoint)
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GST_DEBUG ("%s makes connection possible", node->fac->details.longname);
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else
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GST_DEBUG ("direct connection with %s not possible",
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node->fac->details.longname);
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if ((node->endpoint != NULL) &&
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((bestnode == NULL) || (node->cost < bestnode->cost))) {
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bestnode = node;
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}
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factory_nodes = g_list_prepend (factory_nodes, node);
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/* make curcost the minimum cost of any plugin */
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curcost = node->cost < curcost ? node->cost : curcost;
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factories = g_list_next (factories);
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}
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/* check if we even have possible endpoints */
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if (bestnode == NULL) {
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GST_DEBUG ("no factory found that could connect to sink caps");
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g_list_free_list_and_elements (factory_nodes);
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return NULL;
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}
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/* iterate until we found the best path */
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while (curcost < GST_AUTOPLUG_MAX_COST) {
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GList *nodes = factory_nodes;
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guint nextcost = GST_AUTOPLUG_MAX_COST; /* next cost to check */
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GST_DEBUG ("iterating at current cost %d, bestnode %s at %d", curcost,
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GST_OBJECT_NAME (bestnode->fac), bestnode->cost);
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/* check if we already have a valid best connection to the sink */
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if (bestnode->cost <= curcost) {
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GList *ret;
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GST_DEBUG ("found a way to connect via %s",
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GST_OBJECT_NAME ((GstObject *) bestnode->fac));
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/* enter all factories into the return list */
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ret = g_list_prepend (NULL, bestnode->fac);
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bestnode = bestnode->prev;
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while (bestnode != NULL) {
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ret = g_list_prepend (ret, bestnode->fac);
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bestnode = bestnode->prev;
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}
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g_list_free_list_and_elements (factory_nodes);
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return ret;
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}
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/* iterate over all factories we have
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* if they have the current cost, calculate if this
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* factory supplies shorter paths to other elements
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*/
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while (nodes) {
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if (((GstAutoplugNode *) nodes->data)->cost == curcost) {
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/* now check all elements if we got a shorter path */
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GList *sinknodes = factory_nodes;
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GstAutoplugNode *srcnode = (GstAutoplugNode *) nodes->data;
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while (sinknodes) {
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GstAutoplugNode *sinknode = (GstAutoplugNode *) sinknodes->data;
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GstPadTemplate *templ;
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if ((sinknode->cost >
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srcnode->cost + gst_autoplug_get_cost (sinknode->fac))
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&& (templ = gst_autoplug_can_match (srcnode->fac, sinknode->fac))) {
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/* we got a shorter path
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* now enter that path to that node */
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sinknode->prev = srcnode;
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sinknode->templ = templ;
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sinknode->cost =
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srcnode->cost + gst_autoplug_get_cost (sinknode->fac);
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/* make sure to set which cost to view next */
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nextcost = (nextcost > sinknode->cost) ? sinknode->cost : nextcost;
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/* did we get a new best node? */
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if (sinknode->endpoint && (sinknode->cost < bestnode->cost)) {
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bestnode = sinknode;
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}
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}
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sinknodes = g_list_next (sinknodes);
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}
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/* FIXME: for speed remove the item we just iterated with from the factory_nodes
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* but don't free it yet and don't forget to free it.
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*/
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}
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nodes = g_list_next (nodes);
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}
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curcost = nextcost;
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}
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GST_DEBUG ("found no path from source caps to sink caps");
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g_list_free_list_and_elements (factory_nodes);
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return NULL;
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}
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