/* GStreamer * Copyright (C) 1999-2002 Erik Walthinsen * 2000-2002 Wim Taymans * * 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. */ #include "gstsearchfuncs.h" /* function that really misses in GLib * though the GLib version should take a function as argument... */ 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_can_connect_src: * @src: caps of the source * @sink: caps of the sink * * Checks if a factory's sink can connect to the given caps * * Return: TRUE, if both caps intersect. */ gboolean gst_autoplag_caps_intersect (GstCaps *src, GstCaps *sink) { GstCaps *caps; /* if there are no caps, we can connect */ if ((src == NULL) && (sink == NULL)) return TRUE; /* get an interection */ caps = gst_caps_intersect (src, sink); /* if the caps can't connect, there is no intersection */ if (caps == NULL) return FALSE; /* hurrah, we can connect, 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 * * Return: TRUE, if a connection can be established. */ GstPadTemplate * gst_autoplug_can_connect_src (GstElementFactory *fac, GstCaps *src) { GList *templs; templs = fac->padtemplates; while (templs) { if ((GST_PADTEMPLATE_DIRECTION (templs->data) == GST_PAD_SINK) && gst_autoplag_caps_intersect (src, GST_PADTEMPLATE_CAPS (templs->data))) { return GST_PADTEMPLATE (templs->data); } templs = g_list_next (templs); } return NULL; } /** * gst_autoplug_can_connect_sink: * @fac: factory to connect to * @src: caps to check * * Checks if a factory's src can connect to the given caps * * Return: TRUE, if a connection can be established. */ GstPadTemplate * gst_autoplug_can_connect_sink (GstElementFactory *fac, GstCaps *sink) { GList *templs; templs = fac->padtemplates; while (templs) { if ((GST_PADTEMPLATE_DIRECTION (templs->data) == GST_PAD_SRC) && gst_autoplag_caps_intersect (GST_PADTEMPLATE_CAPS (templs->data), sink)) { return GST_PADTEMPLATE (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_autoplag_caps_intersect (gst_padtemplate_get_caps (srctemp), gst_padtemplate_get_caps (desttemp))) { GST_DEBUG (GST_CAT_AUTOPLUG_ATTEMPT, "factory \"%s\" can connect with factory \"%s\"\n", GST_OBJECT_NAME (src), GST_OBJECT_NAME (dest)); return desttemp; } } desttemps = g_list_next (desttemps); } srctemps = g_list_next (srctemps); } GST_DEBUG (GST_CAT_AUTOPLUG_ATTEMPT, "factory \"%s\" cannot connect with factory \"%s\"\n", 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_PADTEMPLATE_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; } /* returns all factories which have sinks with non-NULL caps and srcs with * any caps. */ GList * gst_autoplug_factories_filters_with_sink_caps (GList *factories) { GList *ret = NULL; while (factories) { GList *templs = ((GstElementFactory *) factories->data)->padtemplates; gboolean have_src = FALSE; gboolean have_sink = FALSE; while (templs) { if (GST_PADTEMPLATE_DIRECTION (templs->data) == GST_PAD_SRC) { have_src = TRUE; } if ((GST_PADTEMPLATE_DIRECTION (templs->data) == GST_PAD_SINK) && (GST_PADTEMPLATE_CAPS (templs->data) != NULL)) { have_sink = TRUE; } if (have_src && have_sink) { ret = g_list_prepend (ret, factories->data); break; } templs = g_list_next (templs); } factories = g_list_next (factories); } return ret; } /* 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_PADTEMPLATE_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: * @srccaps: Caps to plug from * @sinkcaps: Caps to plug to * @factories: GList containing all allowed #GstElementFactory entries * * main function * * Returns: a GList of GstElementFactory items which have to be connected to get * the shortest path. */ GList * gst_autoplug_sp (GstCaps *srccaps, 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 (GST_CAT_AUTOPLUG_ATTEMPT, "attempting to autoplug via shortest path from %s to %s\n", gst_caps_get_mime (srccaps), gst_caps_get_mime (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; 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->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 (GST_CAT_AUTOPLUG_ATTEMPT, "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 (GST_CAT_AUTOPLUG_ATTEMPT, "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 (GST_CAT_AUTOPLUG_ATTEMPT, "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 (GST_CAT_AUTOPLUG_ATTEMPT, "found no path from source caps to sink caps"); g_list_free_list_and_elements (factory_nodes); return NULL; }