gstreamer/gst/gstelement.c
Wim Taymans f4c17c3ba1 Added some more docs
Original commit message from CVS:
Added some more docs
2001-12-09 13:17:54 +00:00

1301 lines
38 KiB
C

/* GStreamer
* Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
* 2000 Wim Taymans <wtay@chello.be>
*
* gstelement.c: The base element, all elements derive from this
*
* 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.
*/
//#define GST_DEBUG_ENABLED
#include <glib.h>
#include "gst_private.h"
#include "gstelement.h"
#include "gstextratypes.h"
#include "gstbin.h"
#include "gstscheduler.h"
#include "gstutils.h"
/* Element signals and args */
enum {
STATE_CHANGE,
NEW_PAD,
PAD_REMOVED,
ERROR,
EOS,
LAST_SIGNAL
};
enum {
ARG_0,
/* FILL ME */
};
static void gst_element_class_init (GstElementClass *klass);
static void gst_element_init (GstElement *element);
static void gst_element_base_class_init (GstElementClass *klass);
static void gst_element_set_property (GObject *object, guint prop_id,
const GValue *value, GParamSpec *pspec);
static void gst_element_get_property (GObject *object, guint prop_id, GValue *value,
GParamSpec *pspec);
static void gst_element_dispose (GObject *object);
static GstElementStateReturn gst_element_change_state (GstElement *element);
#ifndef GST_DISABLE_LOADSAVE
static xmlNodePtr gst_element_save_thyself (GstObject *object, xmlNodePtr parent);
GstElement* gst_element_restore_thyself (xmlNodePtr self, GstObject *parent);
#endif
GType _gst_element_type = 0;
static GstObjectClass *parent_class = NULL;
static guint gst_element_signals[LAST_SIGNAL] = { 0 };
GType gst_element_get_type (void)
{
if (!_gst_element_type) {
static const GTypeInfo element_info = {
sizeof(GstElementClass),
(GBaseInitFunc)gst_element_base_class_init,
NULL,
(GClassInitFunc)gst_element_class_init,
NULL,
NULL,
sizeof(GstElement),
0,
(GInstanceInitFunc)gst_element_init,
NULL
};
_gst_element_type = g_type_register_static(GST_TYPE_OBJECT, "GstElement", &element_info, G_TYPE_FLAG_ABSTRACT);
}
return _gst_element_type;
}
static void
gst_element_class_init (GstElementClass *klass)
{
GObjectClass *gobject_class;
GstObjectClass *gstobject_class;
gobject_class = (GObjectClass*) klass;
gstobject_class = (GstObjectClass*) klass;
parent_class = g_type_class_ref(GST_TYPE_OBJECT);
gst_element_signals[STATE_CHANGE] =
g_signal_new ("state_change", G_TYPE_FROM_CLASS(klass), G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (GstElementClass, state_change), NULL, NULL,
gst_marshal_VOID__INT_INT, G_TYPE_NONE, 2,
G_TYPE_INT, G_TYPE_INT);
gst_element_signals[NEW_PAD] =
g_signal_new ("new_pad", G_TYPE_FROM_CLASS(klass), G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (GstElementClass, new_pad), NULL, NULL,
gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1,
GST_TYPE_PAD);
gst_element_signals[PAD_REMOVED] =
g_signal_new ("pad_removed", G_TYPE_FROM_CLASS(klass), G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (GstElementClass, pad_removed), NULL, NULL,
gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1,
GST_TYPE_PAD);
gst_element_signals[ERROR] =
g_signal_new ("error", G_TYPE_FROM_CLASS(klass), G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (GstElementClass, error), NULL, NULL,
gst_marshal_VOID__STRING, G_TYPE_NONE,1,
G_TYPE_STRING);
gst_element_signals[EOS] =
g_signal_new ("eos", G_TYPE_FROM_CLASS(klass), G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (GstElementClass,eos), NULL, NULL,
gst_marshal_VOID__VOID, G_TYPE_NONE, 0);
gobject_class->set_property = GST_DEBUG_FUNCPTR (gst_element_set_property);
gobject_class->get_property = GST_DEBUG_FUNCPTR (gst_element_get_property);
gobject_class->dispose = GST_DEBUG_FUNCPTR (gst_element_dispose);
#ifndef GST_DISABLE_LOADSAVE
gstobject_class->save_thyself = GST_DEBUG_FUNCPTR (gst_element_save_thyself);
gstobject_class->restore_thyself = GST_DEBUG_FUNCPTR (gst_element_restore_thyself);
#endif
klass->change_state = GST_DEBUG_FUNCPTR (gst_element_change_state);
klass->elementfactory = NULL;
klass->padtemplates = NULL;
klass->numpadtemplates = 0;
}
static void
gst_element_base_class_init (GstElementClass *klass)
{
GObjectClass *gobject_class;
gobject_class = (GObjectClass*) klass;
gobject_class->set_property = GST_DEBUG_FUNCPTR(gst_element_set_property);
gobject_class->get_property = GST_DEBUG_FUNCPTR(gst_element_get_property);
}
static void
gst_element_init (GstElement *element)
{
element->current_state = GST_STATE_NULL;
element->pending_state = -1;
element->numpads = 0;
element->numsrcpads = 0;
element->numsinkpads = 0;
element->pads = NULL;
element->loopfunc = NULL;
element->threadstate = NULL;
element->sched = NULL;
}
static void
gst_element_set_property (GObject *object, guint prop_id, const GValue *value, GParamSpec *pspec)
{
GstElementClass *oclass = (GstElementClass *)G_OBJECT_GET_CLASS(object);
if (oclass->set_property)
(oclass->set_property)(object,prop_id,value,pspec);
}
static void
gst_element_get_property (GObject *object, guint prop_id, GValue *value, GParamSpec *pspec)
{
GstElementClass *oclass = (GstElementClass *)G_OBJECT_GET_CLASS(object);
if (oclass->get_property)
(oclass->get_property)(object,prop_id,value,pspec);
}
/**
* gst_element_set_name:
* @element: GstElement to set name of
* @name: new name of element
*
* Set the name of the element, getting rid of the old name if there was
* one.
*/
void
gst_element_set_name (GstElement *element, const gchar *name)
{
g_return_if_fail (element != NULL);
g_return_if_fail (GST_IS_ELEMENT (element));
g_return_if_fail (name != NULL);
gst_object_set_name (GST_OBJECT (element), name);
}
/**
* gst_element_get_name:
* @element: GstElement to get name of
*
* Get the name of the element.
*
* Returns: name of the element
*/
const gchar*
gst_element_get_name (GstElement *element)
{
g_return_val_if_fail (element != NULL, NULL);
g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
return GST_OBJECT_NAME (element);
}
/**
* gst_element_set_parent:
* @element: GstElement to set parent of
* @parent: new parent of the object
*
* Set the parent of the element.
*/
void
gst_element_set_parent (GstElement *element, GstObject *parent)
{
g_return_if_fail (element != NULL);
g_return_if_fail (GST_IS_ELEMENT (element));
g_return_if_fail (GST_OBJECT_PARENT (element) == NULL);
g_return_if_fail (parent != NULL);
g_return_if_fail (GST_IS_OBJECT (parent));
g_return_if_fail ((gpointer)element != (gpointer)parent);
gst_object_set_parent (GST_OBJECT (element), parent);
}
/**
* gst_element_get_parent:
* @element: GstElement to get the parent of
*
* Get the parent of the element.
*
* Returns: parent of the element
*/
GstObject*
gst_element_get_parent (GstElement *element)
{
g_return_val_if_fail (element != NULL, NULL);
g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
return GST_OBJECT_PARENT (element);
}
/**
* gst_element_add_pad:
* @element: element to add pad to
* @pad: pad to add
*
* Add a pad (connection point) to the element, setting the parent of the
* pad to the element (and thus adding a reference).
*/
void
gst_element_add_pad (GstElement *element, GstPad *pad)
{
g_return_if_fail (element != NULL);
g_return_if_fail (GST_IS_ELEMENT (element));
g_return_if_fail (pad != NULL);
g_return_if_fail (GST_IS_PAD (pad));
// first check to make sure the pad's parent is already set
g_return_if_fail (GST_PAD_PARENT (pad) == NULL);
// then check to see if there's already a pad by that name here
g_return_if_fail (gst_object_check_uniqueness (element->pads, GST_PAD_NAME(pad)) == TRUE);
/* set the pad's parent */
GST_DEBUG (GST_CAT_ELEMENT_PADS,"setting parent of pad '%s' to '%s'\n",
GST_PAD_NAME (pad), GST_ELEMENT_NAME (element));
gst_object_set_parent (GST_OBJECT (pad), GST_OBJECT (element));
/* add it to the list */
element->pads = g_list_append (element->pads, pad);
element->numpads++;
if (gst_pad_get_direction (pad) == GST_PAD_SRC)
element->numsrcpads++;
else
element->numsinkpads++;
/* emit the NEW_PAD signal */
g_signal_emit (G_OBJECT (element), gst_element_signals[NEW_PAD], 0, pad);
}
/**
* gst_element_remove_pad:
* @element: element to remove pad from
* @pad: pad to remove
*
* Remove a pad (connection point) from the element,
*/
void
gst_element_remove_pad (GstElement *element, GstPad *pad)
{
g_return_if_fail (element != NULL);
g_return_if_fail (GST_IS_ELEMENT (element));
g_return_if_fail (pad != NULL);
g_return_if_fail (GST_IS_PAD (pad));
g_return_if_fail (GST_PAD_PARENT (pad) == element);
/* add it to the list */
element->pads = g_list_remove (element->pads, pad);
element->numpads--;
if (gst_pad_get_direction (pad) == GST_PAD_SRC)
element->numsrcpads--;
else
element->numsinkpads--;
g_signal_emit (G_OBJECT (element), gst_element_signals[PAD_REMOVED], 0, pad);
gst_object_unparent (GST_OBJECT (pad));
}
/**
* gst_element_add_ghost_pad:
* @element: element to add ghost pad to
* @pad: pad from which the new ghost pad will be created
* @name: name of the new ghost pad
*
* Create a ghost pad from the given pad, and add it to the list of pads
* for this element.
*/
void
gst_element_add_ghost_pad (GstElement *element, GstPad *pad, gchar *name)
{
GstPad *ghostpad;
g_return_if_fail (element != NULL);
g_return_if_fail (GST_IS_ELEMENT (element));
g_return_if_fail (pad != NULL);
g_return_if_fail (GST_IS_PAD (pad));
// then check to see if there's already a pad by that name here
g_return_if_fail (gst_object_check_uniqueness (element->pads, name) == TRUE);
GST_DEBUG(GST_CAT_ELEMENT_PADS,"creating new ghost pad called %s, from pad %s:%s\n",
name,GST_DEBUG_PAD_NAME(pad));
ghostpad = gst_ghost_pad_new (name, pad);
/* add it to the list */
GST_DEBUG(GST_CAT_ELEMENT_PADS,"adding ghost pad %s to element %s\n",
name, GST_ELEMENT_NAME (element));
element->pads = g_list_append (element->pads, ghostpad);
element->numpads++;
// set the parent of the ghostpad
gst_object_set_parent (GST_OBJECT (ghostpad), GST_OBJECT (element));
GST_DEBUG(GST_CAT_ELEMENT_PADS,"added ghostpad %s:%s\n",GST_DEBUG_PAD_NAME(ghostpad));
/* emit the NEW_GHOST_PAD signal */
g_signal_emit (G_OBJECT (element), gst_element_signals[NEW_PAD], 0, ghostpad);
}
/**
* gst_element_remove_ghost_pad:
* @element: element to remove the ghost pad from
* @pad: ghost pad to remove
*
* removes a ghost pad from an element
*
*/
void
gst_element_remove_ghost_pad (GstElement *element, GstPad *pad)
{
g_return_if_fail (element != NULL);
g_return_if_fail (GST_IS_ELEMENT (element));
g_return_if_fail (pad != NULL);
g_return_if_fail (GST_IS_GHOST_PAD (pad));
// FIXME this is redundant?
// wingo 10-july-2001: I don't think so, you have to actually remove the pad
// from the element. gst_pad_remove_ghost_pad just removes the ghostpad from
// the real pad's ghost pad list
gst_pad_remove_ghost_pad (GST_PAD (GST_PAD_REALIZE (pad)), pad);
gst_element_remove_pad (element, pad);
}
/**
* gst_element_get_pad:
* @element: element to find pad of
* @name: name of pad to retrieve
*
* Retrieve a pad from the element by name.
*
* Returns: requested pad if found, otherwise NULL.
*/
GstPad*
gst_element_get_pad (GstElement *element, const gchar *name)
{
GList *walk;
g_return_val_if_fail (element != NULL, NULL);
g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
g_return_val_if_fail (name != NULL, NULL);
// if there aren't any pads, well, we're not likely to find one
if (!element->numpads)
return NULL;
// look through the list, matching by name
walk = element->pads;
while (walk) {
GstPad *pad = GST_PAD(walk->data);
if (!strcmp (GST_PAD_NAME(pad), name)) {
GST_INFO(GST_CAT_ELEMENT_PADS,"found pad %s:%s",GST_DEBUG_PAD_NAME(pad));
return pad;
}
walk = g_list_next (walk);
}
GST_INFO(GST_CAT_ELEMENT_PADS,"no such pad '%s' in element \"%s\"",name,GST_ELEMENT_NAME(element));
return NULL;
}
/**
* gst_element_get_pad_list:
* @element: element to get pads of
*
* Retrieve a list of the pads associated with the element.
*
* Returns: GList of pads
*/
GList*
gst_element_get_pad_list (GstElement *element)
{
g_return_val_if_fail (element != NULL, NULL);
g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
/* return the list of pads */
return element->pads;
}
/**
* gst_element_class_add_padtemplate:
* @klass: element class to add padtemplate to
* @templ: padtemplate to add
*
* Add a padtemplate to an element class. This is useful if you have derived a custom
* bin and wish to provide an on-request pad at runtime. Plugin writers should use
* gst_elementfactory_add_padtemplate instead.
*/
void
gst_element_class_add_padtemplate (GstElementClass *klass, GstPadTemplate *templ)
{
g_return_if_fail (klass != NULL);
g_return_if_fail (GST_IS_ELEMENT_CLASS (klass));
g_return_if_fail (templ != NULL);
g_return_if_fail (GST_IS_PADTEMPLATE (templ));
klass->padtemplates = g_list_append (klass->padtemplates, templ);
klass->numpadtemplates++;
}
/**
* gst_element_get_padtemplate_list:
* @element: element to get padtemplates of
*
* Retrieve a list of the padtemplates associated with the element.
*
* Returns: GList of padtemplates
*/
GList*
gst_element_get_padtemplate_list (GstElement *element)
{
GstElementClass *oclass;
g_return_val_if_fail (element != NULL, NULL);
g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
oclass = GST_ELEMENT_CLASS (G_OBJECT_GET_CLASS(element));
return oclass->padtemplates;
}
/**
* gst_element_get_padtemplate_by_name:
* @element: element to get padtemplate of
* @name: the name of the padtemplate to get.
*
* Retrieve a padtemplate from this element with the
* given name.
*
* Returns: the padtemplate with the given name
*/
GstPadTemplate*
gst_element_get_padtemplate_by_name (GstElement *element, const guchar *name)
{
GList *padlist;
g_return_val_if_fail (element != NULL, NULL);
g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
g_return_val_if_fail (name != NULL, NULL);
padlist = gst_element_get_padtemplate_list (element);
while (padlist) {
GstPadTemplate *padtempl = (GstPadTemplate*) padlist->data;
if (!strcmp (padtempl->name_template, name))
return padtempl;
padlist = g_list_next (padlist);
}
return NULL;
}
/**
* gst_element_get_padtemplate_by_compatible:
* @element: element to get padtemplate of
* @templ: a template to find a compatible template for
*
* Generate a padtemplate for this element compatible with the given
* template, ie able to link to it.
*
* Returns: the padtemplate
*/
static GstPadTemplate*
gst_element_get_padtemplate_by_compatible (GstElement *element, GstPadTemplate *compattempl)
{
GstPadTemplate *newtempl = NULL;
GList *padlist;
GST_DEBUG(GST_CAT_ELEMENT_PADS,"gst_element_get_padtemplate_by_compatible()\n");
g_return_val_if_fail (element != NULL, NULL);
g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
g_return_val_if_fail (compattempl != NULL, NULL);
padlist = gst_element_get_padtemplate_list (element);
while (padlist) {
GstPadTemplate *padtempl = (GstPadTemplate*) padlist->data;
gboolean compat = FALSE;
// Ignore name
// Ignore presence
// Check direction (must be opposite)
// Check caps
GST_DEBUG(GST_CAT_CAPS,"checking direction and caps\n");
if (padtempl->direction == GST_PAD_SRC &&
compattempl->direction == GST_PAD_SINK) {
GST_DEBUG(GST_CAT_CAPS,"compatible direction: found src pad template\n");
compat = gst_caps_check_compatibility(GST_PADTEMPLATE_CAPS (padtempl),
GST_PADTEMPLATE_CAPS (compattempl));
GST_DEBUG(GST_CAT_CAPS,"caps are %scompatible\n", (compat?"":"not "));
} else if (padtempl->direction == GST_PAD_SINK &&
compattempl->direction == GST_PAD_SRC) {
GST_DEBUG(GST_CAT_CAPS,"compatible direction: found sink pad template\n");
compat = gst_caps_check_compatibility(GST_PADTEMPLATE_CAPS (compattempl),
GST_PADTEMPLATE_CAPS (padtempl));
GST_DEBUG(GST_CAT_CAPS,"caps are %scompatible\n", (compat?"":"not "));
}
if (compat) {
newtempl = padtempl;
break;
}
padlist = g_list_next (padlist);
}
return newtempl;
}
static GstPad*
gst_element_request_pad (GstElement *element, GstPadTemplate *templ, const gchar* name)
{
GstPad *newpad = NULL;
GstElementClass *oclass;
oclass = GST_ELEMENT_CLASS (G_OBJECT_GET_CLASS(element));
if (oclass->request_new_pad)
newpad = (oclass->request_new_pad)(element, templ, name);
return newpad;
}
/**
* gst_element_request_compatible_pad:
* @element: element to request a new pad from
* @templ: a pad template to which the new pad should be able to connect
*
* Request a new pad from the element. The template will
* be used to decide what type of pad to create. This function
* is typically used for elements with a padtemplate with presence
* GST_PAD_REQUEST.
*
* Returns: the new pad that was created.
*/
GstPad*
gst_element_request_compatible_pad (GstElement *element, GstPadTemplate *templ)
{
GstPadTemplate *templ_new;
GstPad *pad = NULL;
g_return_val_if_fail (element != NULL, NULL);
g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
g_return_val_if_fail (templ != NULL, NULL);
templ_new = gst_element_get_padtemplate_by_compatible (element, templ);
if (templ_new != NULL)
pad = gst_element_request_pad (element, templ_new, NULL);
return pad;
}
/**
* gst_element_request_pad_by_name:
* @element: element to request a new pad from
* @name: the name of the padtemplate to use.
*
* Request a new pad from the element. The name argument will
* be used to decide what padtemplate to use. This function
* is typically used for elements with a padtemplate with presence
* GST_PAD_REQUEST.
*
* Returns: the new pad that was created.
*/
GstPad*
gst_element_request_pad_by_name (GstElement *element, const gchar *name)
{
GstPadTemplate *templ = NULL;
GstPad *pad;
const gchar *req_name = NULL;
gboolean templ_found = FALSE;
GList *list;
gint n;
g_return_val_if_fail (element != NULL, NULL);
g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
g_return_val_if_fail (name != NULL, NULL);
if (strstr (name, "%d")) {
templ = gst_element_get_padtemplate_by_name (element, name);
req_name = NULL;
} else {
list = gst_element_get_padtemplate_list(element);
while (!templ_found && list) {
templ = (GstPadTemplate*) list->data;
if (strstr (templ->name_template, "%d")) {
if (sscanf(name, templ->name_template, &n)) {
templ_found = TRUE;
req_name = name;
break;
}
}
list = list->next;
}
}
if (templ == NULL)
return NULL;
pad = gst_element_request_pad (element, templ, req_name);
return pad;
}
/**
* gst_element_connect:
* @src: element containing source pad
* @srcpadname: name of pad in source element
* @dest: element containing destination pad
* @destpadname: name of pad in destination element
*
* Connect the two named pads of the source and destination elements.
* Side effect is that if one of the pads has no parent, it becomes a
* child of the parent of the other element. If they have different
* parents, the connection fails.
*/
void
gst_element_connect (GstElement *src, const gchar *srcpadname,
GstElement *dest, const gchar *destpadname)
{
GstPad *srcpad,*destpad;
g_return_if_fail (src != NULL);
g_return_if_fail (GST_IS_ELEMENT(src));
g_return_if_fail (srcpadname != NULL);
g_return_if_fail (dest != NULL);
g_return_if_fail (GST_IS_ELEMENT(dest));
g_return_if_fail (destpadname != NULL);
/* obtain the pads requested */
srcpad = gst_element_get_pad (src, srcpadname);
if (srcpad == NULL) {
GST_ERROR(src,"source element has no pad \"%s\"",srcpadname);
return;
}
destpad = gst_element_get_pad (dest, destpadname);
if (srcpad == NULL) {
GST_ERROR(dest,"destination element has no pad \"%s\"",destpadname);
return;
}
/* we're satisified they can be connected, let's do it */
gst_pad_connect(srcpad,destpad);
}
/**
* gst_element_disconnect:
* @src: element containing source pad
* @srcpadname: name of pad in source element
* @dest: element containing destination pad
* @destpadname: name of pad in destination element
*
* Disconnect the two named pads of the source and destination elements.
*/
void
gst_element_disconnect (GstElement *src, const gchar *srcpadname,
GstElement *dest, const gchar *destpadname)
{
GstPad *srcpad,*destpad;
g_return_if_fail (src != NULL);
g_return_if_fail (GST_IS_ELEMENT(src));
g_return_if_fail (srcpadname != NULL);
g_return_if_fail (dest != NULL);
g_return_if_fail (GST_IS_ELEMENT(dest));
g_return_if_fail (destpadname != NULL);
/* obtain the pads requested */
srcpad = gst_element_get_pad (src, srcpadname);
if (srcpad == NULL) {
GST_ERROR(src,"source element has no pad \"%s\"",srcpadname);
return;
}
destpad = gst_element_get_pad (dest, destpadname);
if (srcpad == NULL) {
GST_ERROR(dest,"destination element has no pad \"%s\"",destpadname);
return;
}
/* we're satisified they can be disconnected, let's do it */
gst_pad_disconnect(srcpad,destpad);
}
/**
* gst_element_error:
* @element: Element with the error
* @error: String describing the error
*
* This function is used internally by elements to signal an error
* condition. It results in the "error" signal.
*/
void
gst_element_error (GstElement *element, const gchar *error)
{
g_error("GstElement: error in element '%s': %s\n", GST_ELEMENT_NAME(element), error);
/* FIXME: this is not finished!!! */
g_signal_emit (G_OBJECT (element), gst_element_signals[ERROR], 0, error);
}
/**
* gst_element_get_state:
* @element: element to get state of
*
* Gets the state of the element.
*
* Returns: The element state
*/
GstElementState
gst_element_get_state (GstElement *element)
{
g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_VOID_PENDING);
return GST_STATE (element);
}
static void
gst_element_wait_done (GstElement *element, GstElementState old, GstElementState new, GCond *cond)
{
g_signal_handlers_disconnect_by_func (G_OBJECT (element), gst_element_wait_done, cond);
g_cond_signal (cond);
}
/**
* gst_element_wait_state_change:
* @element: element wait for
*
* Wait and block until the element changed its state.
*/
void
gst_element_wait_state_change (GstElement *element)
{
GCond *cond = g_cond_new ();
GMutex *mutex = g_mutex_new ();
g_mutex_lock (mutex);
g_signal_connect (G_OBJECT (element), "state_change", gst_element_wait_done, cond);
g_cond_wait (cond, mutex);
g_mutex_unlock (mutex);
g_mutex_free (mutex);
g_cond_free (cond);
}
/**
* gst_element_set_state:
* @element: element to change state of
* @state: new element state
*
* Sets the state of the element. This function will only set
* the elements pending state.
*
* Returns: whether or not the state was successfully set.
*/
gint
gst_element_set_state (GstElement *element, GstElementState state)
{
GstElementClass *oclass;
GstElementState curpending;
GstElementStateReturn return_val = GST_STATE_SUCCESS;
// g_print("gst_element_set_state(\"%s\",%08lx)\n",
// element->name,state);
g_return_val_if_fail (element != NULL, GST_STATE_FAILURE);
g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_FAILURE);
g_return_val_if_fail (element->sched != NULL, GST_STATE_FAILURE);
GST_DEBUG_ELEMENT (GST_CAT_STATES,element, "setting state from %s to %s\n",
gst_element_statename(GST_STATE(element)),
gst_element_statename(state));
/* start with the current state */
curpending = GST_STATE(element);
/* loop until the final requested state is set */
while (GST_STATE(element) != state && GST_STATE (element) != GST_STATE_VOID_PENDING) {
/* move the curpending state in the correct direction */
if (curpending < state) curpending<<=1;
else curpending>>=1;
/* set the pending state variable */
// FIXME: should probably check to see that we don't already have one
GST_STATE_PENDING (element) = curpending;
if (curpending != state)
GST_DEBUG_ELEMENT (GST_CAT_STATES,element,"intermediate: setting state to %s\n",
gst_element_statename(curpending));
/* call the state change function so it can set the state */
oclass = GST_ELEMENT_CLASS (G_OBJECT_GET_CLASS(element));
if (oclass->change_state)
return_val = (oclass->change_state)(element);
switch (return_val) {
case GST_STATE_FAILURE:
GST_DEBUG_ELEMENT (GST_CAT_STATES,element,"have failed change_state return\n");
return return_val;
case GST_STATE_ASYNC:
GST_DEBUG_ELEMENT (GST_CAT_STATES,element,"element will change state async\n");
return return_val;
default:
/* Last thing we do is verify that a successful state change really
* did change the state... */
if (GST_STATE(element) != curpending) {
GST_DEBUG_ELEMENT (GST_CAT_STATES, element, "element claimed state-change success, but state didn't change\n");
return GST_STATE_FAILURE;
}
break;
}
}
return return_val;
}
static GstElementStateReturn
gst_element_change_state (GstElement *element)
{
GstElementState old_state;
g_return_val_if_fail (element != NULL, GST_STATE_FAILURE);
g_return_val_if_fail (GST_IS_ELEMENT (element), GST_STATE_FAILURE);
old_state = GST_STATE (element);
if (GST_STATE_PENDING (element) == GST_STATE_VOID_PENDING || old_state == GST_STATE_PENDING (element)) {
g_warning ("no state change needed for element %s (VOID_PENDING)\n", GST_ELEMENT_NAME (element));
return GST_STATE_SUCCESS;
}
GST_INFO (GST_CAT_STATES, "%s default handler sets state from %s to %s %d", GST_ELEMENT_NAME (element),
gst_element_statename (old_state),
gst_element_statename (GST_STATE_PENDING (element)),
GST_STATE_TRANSITION (element));
if (GST_STATE_TRANSITION (element) == GST_STATE_PAUSED_TO_PLAYING) {
g_return_val_if_fail (GST_ELEMENT_SCHED (element), GST_STATE_FAILURE);
if (GST_ELEMENT_PARENT (element)) {
GST_DEBUG (GST_CAT_STATES, "PAUSED->PLAYING: element \"%s\" has parent \"%s\" and sched %p\n",
GST_ELEMENT_NAME (element), GST_ELEMENT_NAME (GST_ELEMENT_PARENT (element)),
GST_ELEMENT_SCHED (element));
}
gst_scheduler_enable_element (element->sched, element);
}
else if (GST_STATE_TRANSITION (element) == GST_STATE_PLAYING_TO_PAUSED) {
if (GST_ELEMENT_PARENT (element)) {
GST_DEBUG (GST_CAT_STATES, "PLAYING->PAUSED: element \"%s\" has parent \"%s\" and sched %p\n",
GST_ELEMENT_NAME (element), GST_ELEMENT_NAME (GST_ELEMENT_PARENT (element)),
GST_ELEMENT_SCHED (element));
}
gst_scheduler_disable_element (element->sched, element);
}
GST_STATE (element) = GST_STATE_PENDING (element);
GST_STATE_PENDING (element) = GST_STATE_VOID_PENDING;
// note: queues' state_change is a special case because it needs to lock
// for synchronization (from another thread). since this signal may block
// or (worse) make another state change, the queue needs to unlock before
// calling. thus, gstqueue.c::gst_queue_state_change() blocks, unblocks,
// unlocks, then emits this.
g_signal_emit (G_OBJECT (element), gst_element_signals[STATE_CHANGE], 0,
old_state, GST_STATE (element));
return GST_STATE_SUCCESS;
}
/**
* gst_element_get_factory:
* @element: element to request the factory
*
* Retrieves the factory that was used to create this element
*
* Returns: the factory used for creating this element
*/
GstElementFactory*
gst_element_get_factory (GstElement *element)
{
GstElementClass *oclass;
g_return_val_if_fail (element != NULL, NULL);
g_return_val_if_fail (GST_IS_ELEMENT (element), NULL);
oclass = GST_ELEMENT_CLASS (G_OBJECT_GET_CLASS(element));
return oclass->elementfactory;
}
static void
gst_element_dispose (GObject *object)
{
GstElement *element = GST_ELEMENT (object);
GList *pads;
GstPad *pad;
GST_DEBUG_ELEMENT (GST_CAT_REFCOUNTING, element, "dispose\n");
if (GST_IS_BIN (GST_OBJECT_PARENT (element)))
gst_bin_remove (GST_BIN (GST_OBJECT_PARENT (element)), element);
if (element->pads) {
GList *orig;
orig = pads = g_list_copy (element->pads);
while (pads) {
pad = GST_PAD (pads->data);
// the gst_object_unparent will do the unreffing
gst_element_remove_pad(element, pad);
pads = g_list_next (pads);
}
g_list_free (orig);
g_list_free (element->pads);
element->pads = NULL;
}
element->numsrcpads = 0;
element->numsinkpads = 0;
G_OBJECT_CLASS (parent_class)->dispose (object);
}
#ifndef GST_DISABLE_LOADSAVE
/**
* gst_element_save_thyself:
* @element: GstElement to save
* @parent: the xml parent node
*
* Saves the element as part of the given XML structure
*
* Returns: the new xml node
*/
static xmlNodePtr
gst_element_save_thyself (GstObject *object,
xmlNodePtr parent)
{
GList *pads;
GstElementClass *oclass;
// GType type;
GstElement *element;
g_return_val_if_fail (GST_IS_ELEMENT (object), parent);
element = GST_ELEMENT (object);
oclass = GST_ELEMENT_CLASS (G_OBJECT_GET_CLASS(element));
xmlNewChild(parent, NULL, "name", GST_ELEMENT_NAME(element));
if (oclass->elementfactory != NULL) {
GstElementFactory *factory = (GstElementFactory *)oclass->elementfactory;
xmlNewChild (parent, NULL, "type", GST_OBJECT_NAME (factory));
xmlNewChild (parent, NULL, "version", factory->details->version);
}
// if (element->manager)
// xmlNewChild(parent, NULL, "manager", GST_ELEMENT_NAME(element->manager));
/* FIXME FIXME FIXME!
// output all args to the element
type = G_OBJECT_TYPE (element);
while (type != G_TYPE_INVALID) {
GtkArg *args;
guint32 *flags;
guint num_args,i;
args = gtk_object_query_args (type, &flags, &num_args);
for (i=0; i<num_args; i++) {
if ((args[i].type > G_TYPE_NONE) &&
(flags[i] & GTK_ARG_READABLE)) {
xmlNodePtr arg;
gtk_object_getv (G_OBJECT (element), 1, &args[i]);
arg = xmlNewChild (parent, NULL, "arg", NULL);
xmlNewChild (arg, NULL, "name", args[i].name);
switch (args[i].type) {
case G_TYPE_CHAR:
xmlNewChild (arg, NULL, "value",
g_strdup_printf ("%c", G_VALUE_CHAR (args[i])));
break;
case G_TYPE_UCHAR:
xmlNewChild (arg, NULL, "value",
g_strdup_printf ("%d", G_VALUE_UCHAR (args[i])));
break;
case G_TYPE_BOOL:
xmlNewChild (arg, NULL, "value",
G_VALUE_BOOL (args[i]) ? "true" : "false");
break;
case G_TYPE_INT:
xmlNewChild (arg, NULL, "value",
g_strdup_printf ("%d", G_VALUE_INT (args[i])));
break;
case G_TYPE_LONG:
xmlNewChild (arg, NULL, "value",
g_strdup_printf ("%ld", G_VALUE_LONG (args[i])));
break;
case G_TYPE_ULONG:
xmlNewChild (arg, NULL, "value",
g_strdup_printf ("%lu", G_VALUE_ULONG (args[i])));
break;
case G_TYPE_FLOAT:
xmlNewChild (arg, NULL, "value",
g_strdup_printf ("%f", G_VALUE_FLOAT (args[i])));
break;
case G_TYPE_DOUBLE:
xmlNewChild (arg, NULL, "value",
g_strdup_printf ("%g", G_VALUE_DOUBLE (args[i])));
break;
case G_TYPE_STRING:
xmlNewChild (arg, NULL, "value", G_VALUE_STRING (args[i]));
break;
default:
if (args[i].type == GST_TYPE_FILENAME) {
xmlNewChild (arg, NULL, "value", G_VALUE_STRING (args[i]));
}
break;
}
}
}
type = gtk_type_parent (type);
}
*/
pads = GST_ELEMENT_PADS (element);
while (pads) {
GstPad *pad = GST_PAD (pads->data);
// figure out if it's a direct pad or a ghostpad
if (GST_ELEMENT (GST_OBJECT_PARENT (pad)) == element) {
xmlNodePtr padtag = xmlNewChild (parent, NULL, "pad", NULL);
gst_object_save_thyself (GST_OBJECT (pad), padtag);
}
pads = g_list_next (pads);
}
return parent;
}
/**
* gst_element_restore_thyself:
* @self: the xml node
* @parent: the parent of this object when it's loaded
*
* Load the element from the XML description
*
* Returns: the new element
*/
GstElement*
gst_element_restore_thyself (xmlNodePtr self, GstObject *parent)
{
xmlNodePtr children = self->xmlChildrenNode;
GstElement *element;
GstObjectClass *oclass;
guchar *name = NULL;
guchar *value = NULL;
guchar *type = NULL;
// first get the needed tags to construct the element
while (children) {
if (!strcmp (children->name, "name")) {
name = xmlNodeGetContent (children);
} else if (!strcmp (children->name, "type")) {
type = xmlNodeGetContent (children);
}
children = children->next;
}
g_return_val_if_fail (name != NULL, NULL);
g_return_val_if_fail (type != NULL, NULL);
GST_INFO (GST_CAT_XML,"loading \"%s\" of type \"%s\"", name, type);
element = gst_elementfactory_make (type, name);
g_return_val_if_fail (element != NULL, NULL);
// ne need to set the parent on this object bacause the pads
// will go through the hierarchy to connect to thier peers
if (parent)
gst_object_set_parent (GST_OBJECT (element), parent);
// we have the element now, set the arguments
children = self->xmlChildrenNode;
while (children) {
if (!strcmp (children->name, "arg")) {
xmlNodePtr child = children->xmlChildrenNode;
while (child) {
if (!strcmp (child->name, "name")) {
name = xmlNodeGetContent (child);
}
else if (!strcmp (child->name, "value")) {
value = xmlNodeGetContent (child);
}
child = child->next;
}
gst_util_set_object_arg ((GObject *)G_OBJECT (element), name, value);
}
children = children->next;
}
// we have the element now, set the pads
children = self->xmlChildrenNode;
while (children) {
if (!strcmp (children->name, "pad")) {
gst_pad_load_and_connect (children, GST_OBJECT (element));
}
children = children->next;
}
oclass = GST_OBJECT_CLASS (G_OBJECT_GET_CLASS(element));
if (oclass->restore_thyself)
(oclass->restore_thyself) (GST_OBJECT (element), self);
if (parent)
gst_object_unparent (GST_OBJECT (element));
gst_class_signal_emit_by_name (GST_OBJECT (element), "object_loaded", self);
return element;
}
#endif /* GST_DISABLE_LOADSAVE */
/**
* gst_element_set_sched:
* @element: Element to set manager of.
* @sched: @GstScheduler to set.
*
* Sets the scheduler of the element. For internal use only, unless you're
* writing a new bin subclass.
*/
void
gst_element_set_sched (GstElement *element,
GstScheduler *sched)
{
GST_INFO_ELEMENT (GST_CAT_PARENTAGE, element, "setting scheduler to %p",sched);
element->sched = sched;
}
/**
* gst_element_get_sched:
* @element: Element to get manager of.
*
* Returns the scheduler of the element.
*
* Returns: Element's scheduler
*/
GstScheduler*
gst_element_get_sched (GstElement *element)
{
return element->sched;
}
/**
* gst_element_set_loop_function:
* @element: Element to set loop function of.
* @loop: Pointer to loop function.
*
* This sets the loop function for the element. The function pointed to
* can deviate from the GstElementLoopFunction definition in type of
* pointer only.
*
* NOTE: in order for this to take effect, the current loop function *must*
* exit. Assuming the loop function itself is the only one who will cause
* a new loopfunc to be assigned, this should be no problem.
*/
void
gst_element_set_loop_function(GstElement *element,
GstElementLoopFunction loop)
{
/* set the loop function */
element->loopfunc = loop;
/* set the NEW_LOOPFUNC flag so everyone knows to go try again */
GST_FLAG_SET(element,GST_ELEMENT_NEW_LOOPFUNC);
}
/**
* gst_element_signal_eos:
* @element: element to trigger the eos signal of
*
* Throws the eos signal to indicate that the end of the stream is reached.
*/
void
gst_element_signal_eos (GstElement *element)
{
g_return_if_fail (element != NULL);
g_return_if_fail (GST_IS_ELEMENT (element));
GST_DEBUG(GST_CAT_EVENT, "signaling EOS on element %s\n",GST_OBJECT_NAME(element));
g_signal_emit (G_OBJECT (element), gst_element_signals[EOS], 0);
GST_FLAG_SET(element,GST_ELEMENT_COTHREAD_STOPPING);
}
/**
* gst_element_statename:
* @state: The state to get the name of
*
* Gets a string representing the given state.
*
* Returns: a string with the statename.
*/
const gchar*
gst_element_statename (GstElementState state)
{
switch (state) {
#ifdef GST_DEBUG_COLOR
case GST_STATE_VOID_PENDING: return "NONE_PENDING";break;
case GST_STATE_NULL: return "\033[01;37mNULL\033[00m";break;
case GST_STATE_READY: return "\033[01;31mREADY\033[00m";break;
case GST_STATE_PLAYING: return "\033[01;32mPLAYING\033[00m";break;
case GST_STATE_PAUSED: return "\033[01;33mPAUSED\033[00m";break;
default: return g_strdup_printf ("\033[01;37;41mUNKNOWN!\033[00m(%d)", state);
#else
case GST_STATE_VOID_PENDING: return "NONE_PENDING";break;
case GST_STATE_NULL: return "NULL";break;
case GST_STATE_READY: return "READY";break;
case GST_STATE_PLAYING: return "PLAYING";break;
case GST_STATE_PAUSED: return "PAUSED";break;
default: return "UNKNOWN!";
#endif
}
return "";
}