gstreamer/gst/autoplug/gstsearchfuncs.c
Wim Taymans c47dc4d853 First THREADED backport attempt, focusing on adding locks and making sure the API is threadsafe. Needs more work. Mor...
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.
2005-03-07 18:27:42 +00:00

440 lines
13 KiB
C

/* GStreamer
* Copyright (C) 1999-2002 Erik Walthinsen <omega@cse.ogi.edu>
* 2000-2002 Wim Taymans <wtay@chello.be>
*
* gstsearchfuncs.c: functions needed when doing searches while
* autoplugging
*
* 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 "gstsearchfuncs.h"
/* FIXME: "evil hack" alarm, we need a better way to get a category in here */
GST_DEBUG_CATEGORY_EXTERN (GST_CAT_AUTOPLUG_ATTEMPT);
#define GST_CAT_DEFAULT GST_CAT_AUTOPLUG_ATTEMPT
/* function that really misses in GLib
* though the GLib version should take a function as argument...
*/
static void
g_list_free_list_and_elements (GList * list)
{
GList *walk = list;
while (walk) {
g_free (walk->data);
walk = g_list_next (walk);
}
g_list_free (list);
}
/**
* gst_autoplug_caps_intersect:
* @src: a source #GstCaps
* @sink: the sink #GstCaps
*
* Checks if the given caps have a non-null intersection.
*
* Returns: TRUE, if both caps intersect.
*/
gboolean
gst_autoplug_caps_intersect (const GstCaps * src, const GstCaps * sink)
{
GstCaps *caps;
/* get an intersection */
caps = gst_caps_intersect (src, sink);
/* if the caps can't link, there is no intersection */
if (gst_caps_is_empty (caps)) {
gst_caps_unref (caps);
return FALSE;
}
/* hurrah, we can link, now remove the intersection */
gst_caps_unref (caps);
return TRUE;
}
/**
* gst_autoplug_can_connect_src:
* @fac: factory to connect to
* @src: caps to check
*
* Checks if a factory's sink can connect to the given caps
*
* Returns: #GstPadTemplate that can connect to the given caps
*/
GstPadTemplate *
gst_autoplug_can_connect_src (GstElementFactory * fac, const GstCaps * src)
{
GList *templs;
templs = fac->padtemplates;
while (templs) {
if ((GST_PAD_TEMPLATE_DIRECTION (templs->data) == GST_PAD_SINK) &&
gst_autoplug_caps_intersect (src,
GST_PAD_TEMPLATE_CAPS (templs->data))) {
return GST_PAD_TEMPLATE (templs->data);
}
templs = g_list_next (templs);
}
return NULL;
}
/**
* gst_autoplug_can_connect_sink:
* @fac: factory to connect to
* @sink: caps to check
*
* Checks if a factory's src can connect to the given caps
*
* Returns: #GstPadTemplate that can connect to the given caps
*/
GstPadTemplate *
gst_autoplug_can_connect_sink (GstElementFactory * fac, const GstCaps * sink)
{
GList *templs;
templs = fac->padtemplates;
while (templs) {
GstCaps *caps = GST_PAD_TEMPLATE_CAPS (templs->data);
if ((GST_PAD_TEMPLATE_DIRECTION (templs->data) == GST_PAD_SRC) &&
gst_autoplug_caps_intersect (caps, sink)) {
return GST_PAD_TEMPLATE (templs->data);
}
templs = g_list_next (templs);
}
return NULL;
}
GstPadTemplate *
gst_autoplug_can_match (GstElementFactory * src, GstElementFactory * dest)
{
GList *srctemps, *desttemps;
srctemps = src->padtemplates;
while (srctemps) {
GstPadTemplate *srctemp = (GstPadTemplate *) srctemps->data;
desttemps = dest->padtemplates;
while (desttemps) {
GstPadTemplate *desttemp = (GstPadTemplate *) desttemps->data;
if (srctemp->direction == GST_PAD_SRC &&
desttemp->direction == GST_PAD_SINK) {
if (gst_autoplug_caps_intersect (gst_pad_template_get_caps (srctemp),
gst_pad_template_get_caps (desttemp))) {
GST_DEBUG ("factory \"%s\" can connect with factory \"%s\"",
GST_OBJECT_NAME (src), GST_OBJECT_NAME (dest));
return desttemp;
}
}
desttemps = g_list_next (desttemps);
}
srctemps = g_list_next (srctemps);
}
GST_DEBUG ("factory \"%s\" cannot connect with factory \"%s\"",
GST_OBJECT_NAME (src), GST_OBJECT_NAME (dest));
return NULL;
}
/* returns TRUE if the factory has padtemplates with the specified direction */
gboolean
gst_autoplug_factory_has_direction (GstElementFactory * fac,
GstPadDirection dir)
{
GList *templs = fac->padtemplates;
while (templs) {
if (GST_PAD_TEMPLATE_DIRECTION (templs->data) == dir) {
return TRUE;
}
templs = g_list_next (templs);
}
return FALSE;
}
/* Decisions are based on the padtemplates.
* These functions return a new list so be sure to free it.
*/
GList *
gst_autoplug_factories_sinks (GList * factories)
{
GList *ret = NULL;
while (factories) {
if (gst_autoplug_factory_has_sink (factories->data))
ret = g_list_prepend (ret, factories->data);
factories = g_list_next (factories);
}
return ret;
}
GList *
gst_autoplug_factories_srcs (GList * factories)
{
GList *ret = NULL;
while (factories) {
if (gst_autoplug_factory_has_src (factories->data))
ret = g_list_prepend (ret, factories->data);
factories = g_list_next (factories);
}
return ret;
}
GList *
gst_autoplug_factories_filters (GList * factories)
{
GList *ret = NULL;
while (factories) {
/* if you want it faster do src/sink check at once, don't call two functions */
if (gst_autoplug_factory_has_src (factories->data)
&& gst_autoplug_factory_has_sink (factories->data))
ret = g_list_prepend (ret, factories->data);
factories = g_list_next (factories);
}
return ret;
}
static gint
gst_autoplug_rank_compare (const GstElementFactory * a,
const GstElementFactory * b)
{
if (GST_PLUGIN_FEATURE (a)->rank > GST_PLUGIN_FEATURE (b)->rank)
return -1;
return (GST_PLUGIN_FEATURE (a)->rank < GST_PLUGIN_FEATURE (b)->rank) ? 1 : 0;
}
/* returns all factories which have sinks with non-NULL caps and srcs with
* any caps. also only returns factories with a non-zero rank, and sorts by
* rank descending.
*/
GList *
gst_autoplug_factories_filters_with_sink_caps (GList * factories)
{
GList *ret = NULL;
GstElementFactory *factory;
GList *templs;
while (factories) {
factory = (GstElementFactory *) factories->data;
templs = factory->padtemplates;
if (GST_PLUGIN_FEATURE (factory)->rank > 0) {
gboolean have_src = FALSE;
gboolean have_sink = FALSE;
while (templs) {
if (GST_PAD_TEMPLATE_DIRECTION (templs->data) == GST_PAD_SRC) {
have_src = TRUE;
}
if ((GST_PAD_TEMPLATE_DIRECTION (templs->data) == GST_PAD_SINK)
&& (GST_PAD_TEMPLATE_CAPS (templs->data) != NULL)) {
have_sink = TRUE;
}
if (have_src && have_sink) {
ret = g_list_prepend (ret, factory);
break;
}
templs = g_list_next (templs);
}
}
factories = g_list_next (factories);
}
return g_list_sort (ret, (GCompareFunc) gst_autoplug_rank_compare);
}
/* returns all factories which have a maximum of maxtemplates GstPadTemplates in direction dir
*/
GList *
gst_autoplug_factories_at_most_templates (GList * factories,
GstPadDirection dir, guint maxtemplates)
{
GList *ret = NULL;
while (factories) {
guint count = 0;
GList *templs = ((GstElementFactory *) factories->data)->padtemplates;
while (templs) {
if (GST_PAD_TEMPLATE_DIRECTION (templs->data) == dir) {
count++;
}
if (count > maxtemplates)
break;
templs = g_list_next (templs);
}
if (count <= maxtemplates)
ret = g_list_prepend (ret, factories->data);
factories = g_list_next (factories);
}
return ret;
}
/*********************************************************************
*
* SHORTEST PATH ALGORITHM
*/
/**
* gst_autoplug_sp:
* @src_caps: a #GstCaps to plug from.
* @sink_caps: the #GstCaps to plug to.
* @factories: a #GList containing all allowed #GstElementFactory entries.
*
* Finds the shortest path of elements that together make up a possible
* connection between the source and sink caps.
*
* Returns: a #GList of #GstElementFactory items which have to be connected
* to get the shortest path.
*/
GList *
gst_autoplug_sp (const GstCaps * srccaps, const GstCaps * sinkcaps,
GList * factories)
{
GList *factory_nodes = NULL;
guint curcost = GST_AUTOPLUG_MAX_COST; /* below this cost, there is no path */
GstAutoplugNode *bestnode = NULL; /* best (unconnected) endpoint currently */
g_return_val_if_fail (srccaps != NULL, NULL);
g_return_val_if_fail (sinkcaps != NULL, NULL);
GST_INFO ("attempting to autoplug via shortest path from %"
GST_PTR_FORMAT " to %" GST_PTR_FORMAT, srccaps, sinkcaps);
/* wrap all factories as GstAutoplugNode
* initialize the cost */
while (factories) {
GstAutoplugNode *node = g_new0 (GstAutoplugNode, 1);
node->prev = NULL;
node->fac = (GstElementFactory *) factories->data;
GST_DEBUG ("trying with %s", node->fac->details.longname);
node->templ = gst_autoplug_can_connect_src (node->fac, srccaps);
node->cost = (node->templ ? gst_autoplug_get_cost (node->fac)
: GST_AUTOPLUG_MAX_COST);
node->endpoint = gst_autoplug_can_connect_sink (node->fac, sinkcaps);
if (node->templ && node->endpoint)
GST_DEBUG ("%s makes connection possible", node->fac->details.longname);
else
GST_DEBUG ("direct connection with %s not possible",
node->fac->details.longname);
if ((node->endpoint != NULL) &&
((bestnode == NULL) || (node->cost < bestnode->cost))) {
bestnode = node;
}
factory_nodes = g_list_prepend (factory_nodes, node);
/* make curcost the minimum cost of any plugin */
curcost = node->cost < curcost ? node->cost : curcost;
factories = g_list_next (factories);
}
/* check if we even have possible endpoints */
if (bestnode == NULL) {
GST_DEBUG ("no factory found that could connect to sink caps");
g_list_free_list_and_elements (factory_nodes);
return NULL;
}
/* iterate until we found the best path */
while (curcost < GST_AUTOPLUG_MAX_COST) {
GList *nodes = factory_nodes;
guint nextcost = GST_AUTOPLUG_MAX_COST; /* next cost to check */
GST_DEBUG ("iterating at current cost %d, bestnode %s at %d", curcost,
GST_OBJECT_NAME (bestnode->fac), bestnode->cost);
/* check if we already have a valid best connection to the sink */
if (bestnode->cost <= curcost) {
GList *ret;
GST_DEBUG ("found a way to connect via %s",
GST_OBJECT_NAME ((GstObject *) bestnode->fac));
/* enter all factories into the return list */
ret = g_list_prepend (NULL, bestnode->fac);
bestnode = bestnode->prev;
while (bestnode != NULL) {
ret = g_list_prepend (ret, bestnode->fac);
bestnode = bestnode->prev;
}
g_list_free_list_and_elements (factory_nodes);
return ret;
}
/* iterate over all factories we have
* if they have the current cost, calculate if this
* factory supplies shorter paths to other elements
*/
while (nodes) {
if (((GstAutoplugNode *) nodes->data)->cost == curcost) {
/* now check all elements if we got a shorter path */
GList *sinknodes = factory_nodes;
GstAutoplugNode *srcnode = (GstAutoplugNode *) nodes->data;
while (sinknodes) {
GstAutoplugNode *sinknode = (GstAutoplugNode *) sinknodes->data;
GstPadTemplate *templ;
if ((sinknode->cost >
srcnode->cost + gst_autoplug_get_cost (sinknode->fac))
&& (templ = gst_autoplug_can_match (srcnode->fac, sinknode->fac))) {
/* we got a shorter path
* now enter that path to that node */
sinknode->prev = srcnode;
sinknode->templ = templ;
sinknode->cost =
srcnode->cost + gst_autoplug_get_cost (sinknode->fac);
/* make sure to set which cost to view next */
nextcost = (nextcost > sinknode->cost) ? sinknode->cost : nextcost;
/* did we get a new best node? */
if (sinknode->endpoint && (sinknode->cost < bestnode->cost)) {
bestnode = sinknode;
}
}
sinknodes = g_list_next (sinknodes);
}
/* FIXME: for speed remove the item we just iterated with from the factory_nodes
* but don't free it yet and don't forget to free it.
*/
}
nodes = g_list_next (nodes);
}
curcost = nextcost;
}
GST_DEBUG ("found no path from source caps to sink caps");
g_list_free_list_and_elements (factory_nodes);
return NULL;
}