gstreamer/ext/gconf/gstswitchsrc.c

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/* GStreamer
* Copyright (c) 2005 Ronald S. Bultje <rbultje@ronald.bitfreak.net>
* Copyright (c) 2006 Jürg Billeter <j@bitron.ch>
* Copyright (c) 2007 Jan Schmidt <thaytan@noraisin.net>
* Copyright (c) 2010 Sebastian Dröge <sebastian.droege@collabora.co.uk>
*
* 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 <string.h>
#include "gstswitchsrc.h"
GST_DEBUG_CATEGORY_STATIC (switch_debug);
#define GST_CAT_DEFAULT switch_debug
static void gst_switch_src_dispose (GObject * object);
static GstStateChangeReturn
gst_switch_src_change_state (GstElement * element, GstStateChange transition);
GST_BOILERPLATE (GstSwitchSrc, gst_switch_src, GstBin, GST_TYPE_BIN);
static void
gst_switch_src_base_init (gpointer klass)
{
GST_DEBUG_CATEGORY_INIT (switch_debug, "switchsrc", 0, "switchsrc element");
}
static void
gst_switch_src_class_init (GstSwitchSrcClass * klass)
{
GObjectClass *oklass = G_OBJECT_CLASS (klass);
GstElementClass *eklass = GST_ELEMENT_CLASS (klass);
static GstStaticPadTemplate src_template = GST_STATIC_PAD_TEMPLATE ("src",
GST_PAD_SRC,
GST_PAD_ALWAYS,
GST_STATIC_CAPS_ANY);
GstPadTemplate *child_pad_templ;
oklass->dispose = gst_switch_src_dispose;
eklass->change_state = gst_switch_src_change_state;
/* Provide a default pad template if the child didn't */
child_pad_templ = gst_element_class_get_pad_template (eklass, "src");
if (child_pad_templ == NULL) {
gst_element_class_add_pad_template (eklass,
gst_static_pad_template_get (&src_template));
}
}
static gboolean
gst_switch_src_reset (GstSwitchSrc * src)
{
/* this will install fakesrc if no other child has been set,
* otherwise we rely on the subclass to know when to unset its
* custom kid */
if (src->kid == NULL) {
return gst_switch_src_set_child (src, NULL);
}
return TRUE;
}
static void
gst_switch_src_init (GstSwitchSrc * src, GstSwitchSrcClass * g_class)
{
GstElementClass *eklass = GST_ELEMENT_GET_CLASS (src);
GstPadTemplate *templ;
templ = gst_element_class_get_pad_template (eklass, "src");
src->pad = gst_ghost_pad_new_no_target_from_template ("src", templ);
gst_element_add_pad (GST_ELEMENT (src), src->pad);
gst_switch_src_reset (src);
}
static void
gst_switch_src_dispose (GObject * object)
{
GstSwitchSrc *src = GST_SWITCH_SRC (object);
GstObject *new_kid, *kid;
GST_OBJECT_LOCK (src);
new_kid = GST_OBJECT_CAST (src->new_kid);
src->new_kid = NULL;
kid = GST_OBJECT_CAST (src->kid);
src->kid = NULL;
GST_OBJECT_UNLOCK (src);
gst_object_replace (&new_kid, NULL);
gst_object_replace (&kid, NULL);
GST_CALL_PARENT (G_OBJECT_CLASS, dispose, (object));
}
static gboolean
gst_switch_src_commit_new_kid (GstSwitchSrc * src)
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{
GstPad *targetpad;
GstState kid_state;
GstElement *new_kid, *old_kid;
gboolean is_fakesrc = FALSE;
GstBus *bus;
/* need locking around member accesses */
GST_OBJECT_LOCK (src);
/* If we're currently changing state, set the child to the next state
* we're transitioning too, rather than our current state which is
* about to change */
if (GST_STATE_NEXT (src) != GST_STATE_VOID_PENDING)
kid_state = GST_STATE_NEXT (src);
else
kid_state = GST_STATE (src);
new_kid = src->new_kid ? gst_object_ref (src->new_kid) : NULL;
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src->new_kid = NULL;
GST_OBJECT_UNLOCK (src);
/* Fakesrc by default if NULL is passed as the new child */
if (new_kid == NULL) {
GST_DEBUG_OBJECT (src, "Replacing kid with fakesrc");
new_kid = gst_element_factory_make ("fakesrc", "testsrc");
if (new_kid == NULL) {
GST_ERROR_OBJECT (src, "Failed to create fakesrc");
return FALSE;
}
/* Add a reference, as it would if the element came from src->new_kid */
gst_object_ref (new_kid);
is_fakesrc = TRUE;
} else {
GST_DEBUG_OBJECT (src, "Setting new kid");
}
/* set temporary bus of our own to catch error messages from the child
* (could we just set our own bus on it, or would the state change messages
* from the not-yet-added element confuse the state change algorithm? Let's
* play it safe for now) */
bus = gst_bus_new ();
gst_element_set_bus (new_kid, bus);
gst_object_unref (bus);
if (gst_element_set_state (new_kid, kid_state) == GST_STATE_CHANGE_FAILURE) {
GstMessage *msg;
/* check if child posted an error message and if so re-post it on our bus
* so that the application gets to see a decent error and not our generic
* fallback error message which is completely indecipherable to the user */
msg = gst_bus_pop_filtered (GST_ELEMENT_BUS (new_kid), GST_MESSAGE_ERROR);
if (msg) {
GST_INFO_OBJECT (src, "Forwarding kid error: %" GST_PTR_FORMAT, msg);
gst_element_post_message (GST_ELEMENT (src), msg);
}
GST_ELEMENT_ERROR (src, CORE, STATE_CHANGE, (NULL),
("Failed to set state on new child."));
gst_element_set_bus (new_kid, NULL);
gst_object_unref (new_kid);
return FALSE;
}
gst_element_set_bus (new_kid, NULL);
gst_bin_add (GST_BIN (src), new_kid);
/* Now, replace the existing child */
GST_OBJECT_LOCK (src);
old_kid = src->kid;
src->kid = new_kid;
/* Mark whether a custom kid or fakesrc has been installed */
src->have_kid = !is_fakesrc;
GST_OBJECT_UNLOCK (src);
/* kill old element */
if (old_kid) {
GST_DEBUG_OBJECT (src, "Removing old kid %" GST_PTR_FORMAT, old_kid);
gst_element_set_state (old_kid, GST_STATE_NULL);
gst_bin_remove (GST_BIN (src), old_kid);
gst_object_unref (old_kid);
}
/* re-attach ghostpad */
GST_DEBUG_OBJECT (src, "Creating new ghostpad");
targetpad = gst_element_get_static_pad (src->kid, "src");
gst_ghost_pad_set_target (GST_GHOST_PAD (src->pad), targetpad);
gst_object_unref (targetpad);
GST_DEBUG_OBJECT (src, "done changing child of switchsrc");
return TRUE;
}
gboolean
gst_switch_src_set_child (GstSwitchSrc * src, GstElement * new_kid)
{
GstState cur, next;
GstElement **p_kid;
/* Nothing to do if clearing the child and we've already installed fakesrc */
if (new_kid == NULL && src->kid != NULL && src->have_kid == FALSE)
return TRUE;
/* Store the new kid to be committed later */
GST_OBJECT_LOCK (src);
cur = GST_STATE (src);
next = GST_STATE_NEXT (src);
p_kid = &src->new_kid;
gst_object_replace ((GstObject **) p_kid, (GstObject *) new_kid);
GST_OBJECT_UNLOCK (src);
if (new_kid)
gst_object_unref (new_kid);
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/* Sometime, it would be lovely to allow src changes even when
* already running */
/* FIXME: Block the pad and replace the kid when it completes */
if (cur > GST_STATE_READY || next == GST_STATE_PAUSED) {
GST_DEBUG_OBJECT (src,
"Switch-src is already running. Ignoring change of child.");
gst_object_unref (new_kid);
return TRUE;
}
return gst_switch_src_commit_new_kid (src);
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}
static GstStateChangeReturn
gst_switch_src_change_state (GstElement * element, GstStateChange transition)
{
GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
GstSwitchSrc *src = GST_SWITCH_SRC (element);
ret = GST_CALL_PARENT_WITH_DEFAULT (GST_ELEMENT_CLASS, change_state,
(element, transition), GST_STATE_CHANGE_SUCCESS);
switch (transition) {
case GST_STATE_CHANGE_READY_TO_NULL:
if (!gst_switch_src_reset (src))
ret = GST_STATE_CHANGE_FAILURE;
break;
default:
break;
}
return ret;
}