root/gst/gstpadtemplate.c
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DEFINITIONS
This source file includes following definitions.
- gst_pad_template_class_init
- gst_pad_template_init
- gst_pad_template_dispose
- name_is_valid
- gst_static_pad_template_get_type
- gst_static_pad_template_get
- gst_pad_template_new
- gst_static_pad_template_get_caps
- gst_pad_template_get_caps
- gst_pad_template_pad_created
- gst_pad_template_set_property
- gst_pad_template_get_property
/* GStreamer
* Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
* 2000 Wim Taymans <wtay@chello.be>
*
* gstpadtemplate.c: Templates for pad creation
*
* 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.
*/
/**
* SECTION:gstpadtemplate
* @short_description: Describe the media type of a pad.
* @see_also: #GstPad, #GstElementFactory
*
* Padtemplates describe the possible media types a pad or an elementfactory can
* handle. This allows for both inspection of handled types before loading the
* element plugin as well as identifying pads on elements that are not yet
* created (request or sometimes pads).
*
* Pad and PadTemplates have #GstCaps attached to it to describe the media type
* they are capable of dealing with. gst_pad_template_get_caps() or
* GST_PAD_TEMPLATE_CAPS() are used to get the caps of a padtemplate. It's not
* possible to modify the caps of a padtemplate after creation.
*
* PadTemplates have a #GstPadPresence property which identifies the lifetime
* of the pad and that can be retrieved with GST_PAD_TEMPLATE_PRESENCE(). Also
* the direction of the pad can be retrieved from the #GstPadTemplate with
* GST_PAD_TEMPLATE_DIRECTION().
*
* The GST_PAD_TEMPLATE_NAME_TEMPLATE () is important for GST_PAD_REQUEST pads
* because it has to be used as the name in the gst_element_get_request_pad()
* call to instantiate a pad from this template.
*
* Padtemplates can be created with gst_pad_template_new() or with
* gst_static_pad_template_get (), which creates a #GstPadTemplate from a
* #GstStaticPadTemplate that can be filled with the
* convenient GST_STATIC_PAD_TEMPLATE() macro.
*
* A padtemplate can be used to create a pad (see gst_pad_new_from_template()
* or gst_pad_new_from_static_template ()) or to add to an element class
* (see gst_element_class_add_pad_template ()).
*
* The following code example shows the code to create a pad from a padtemplate.
* <example>
* <title>Create a pad from a padtemplate</title>
* <programlisting>
* GstStaticPadTemplate my_template =
* GST_STATIC_PAD_TEMPLATE (
* "sink", // the name of the pad
* GST_PAD_SINK, // the direction of the pad
* GST_PAD_ALWAYS, // when this pad will be present
* GST_STATIC_CAPS ( // the capabilities of the padtemplate
* "audio/x-raw-int, "
* "channels = (int) [ 1, 6 ]"
* )
* )
* void
* my_method (void)
* {
* GstPad *pad;
* pad = gst_pad_new_from_static_template (&my_template, "sink");
* ...
* }
* </programlisting>
* </example>
*
* The following example shows you how to add the padtemplate to an
* element class, this is usually done in the base_init of the class:
* <informalexample>
* <programlisting>
* static void
* my_element_base_init (gpointer g_class)
* {
* GstElementClass *gstelement_class = GST_ELEMENT_CLASS (g_class);
*
* gst_element_class_add_pad_template (gstelement_class,
* gst_static_pad_template_get (&my_template));
* }
* </programlisting>
* </informalexample>
*
* Last reviewed on 2006-02-14 (0.10.3)
*/
#include "gst_private.h"
#include "gstpad.h"
#include "gstpadtemplate.h"
#include "gstenumtypes.h"
#include "gstmarshal.h"
#include "gstutils.h"
#include "gstinfo.h"
#include "gsterror.h"
#include "gstvalue.h"
#define GST_CAT_DEFAULT GST_CAT_PADS
enum
{
PROP_NAME_TEMPLATE = 1,
PROP_DIRECTION,
PROP_PRESENCE,
PROP_CAPS
};
enum
{
TEMPL_PAD_CREATED,
/* FILL ME */
LAST_SIGNAL
};
static GstObject *parent_class = NULL;
static guint gst_pad_template_signals[LAST_SIGNAL] = { 0 };
static void gst_pad_template_dispose (GObject * object);
static void gst_pad_template_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec);
static void gst_pad_template_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec);
G_DEFINE_TYPE (GstPadTemplate, gst_pad_template, GST_TYPE_OBJECT);
static void
gst_pad_template_class_init (GstPadTemplateClass * klass)
{
GObjectClass *gobject_class;
GstObjectClass *gstobject_class;
gobject_class = (GObjectClass *) klass;
gstobject_class = (GstObjectClass *) klass;
parent_class = g_type_class_peek_parent (klass);
/**
* GstPadTemplate::pad-created:
* @pad_template: the object which received the signal.
* @pad: the pad that was created.
*
* This signal is fired when an element creates a pad from this template.
*/
gst_pad_template_signals[TEMPL_PAD_CREATED] =
g_signal_new ("pad-created", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (GstPadTemplateClass, pad_created),
NULL, NULL, gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, GST_TYPE_PAD);
gobject_class->dispose = gst_pad_template_dispose;
gobject_class->get_property = gst_pad_template_get_property;
gobject_class->set_property = gst_pad_template_set_property;
/**
* GstPadTemplate:name-template
*
* The name template of the pad template.
*
* Since: 0.10.21
*/
g_object_class_install_property (gobject_class, PROP_NAME_TEMPLATE,
g_param_spec_string ("name-template", "Name template",
"The name template of the pad template", NULL,
G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY | G_PARAM_STATIC_STRINGS));
/**
* GstPadTemplate:direction
*
* The direction of the pad described by the pad template.
*
* Since: 0.10.21
*/
g_object_class_install_property (gobject_class, PROP_DIRECTION,
g_param_spec_enum ("direction", "Direction",
"The direction of the pad described by the pad template",
GST_TYPE_PAD_DIRECTION, GST_PAD_UNKNOWN,
G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY | G_PARAM_STATIC_STRINGS));
/**
* GstPadTemplate:presence
*
* When the pad described by the pad template will become available.
*
* Since: 0.10.21
*/
g_object_class_install_property (gobject_class, PROP_PRESENCE,
g_param_spec_enum ("presence", "Presence",
"When the pad described by the pad template will become available",
GST_TYPE_PAD_PRESENCE, GST_PAD_ALWAYS,
G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY | G_PARAM_STATIC_STRINGS));
/**
* GstPadTemplate:caps
*
* The capabilities of the pad described by the pad template.
*
* Since: 0.10.21
*/
g_object_class_install_property (gobject_class, PROP_CAPS,
g_param_spec_boxed ("caps", "Caps",
"The capabilities of the pad described by the pad template",
GST_TYPE_CAPS,
G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY | G_PARAM_STATIC_STRINGS));
gstobject_class->path_string_separator = "*";
}
static void
gst_pad_template_init (GstPadTemplate * templ)
{
/* FIXME 0.11: Does anybody remember why this is here? If not, let's
* change it for 0.11 and let gst_element_class_add_pad_template() for
* example ref/sink the pad templates.
*/
/* We ensure that the pad template we're creating has a sunken reference.
* Inconsistencies in pad templates being floating or sunken has caused
* problems in the past with leaks, etc.
*
* For consistency, then, we only produce them with sunken references
* owned by the creator of the object
*/
if (GST_OBJECT_IS_FLOATING (templ)) {
gst_object_ref_sink (templ);
}
}
static void
gst_pad_template_dispose (GObject * object)
{
GstPadTemplate *templ = GST_PAD_TEMPLATE (object);
g_free (GST_PAD_TEMPLATE_NAME_TEMPLATE (templ));
if (GST_PAD_TEMPLATE_CAPS (templ)) {
gst_caps_unref (GST_PAD_TEMPLATE_CAPS (templ));
}
G_OBJECT_CLASS (parent_class)->dispose (object);
}
/* ALWAYS padtemplates cannot have conversion specifications (like src_%d),
* since it doesn't make sense.
* SOMETIMES padtemplates can do whatever they want, they are provided by the
* element.
* REQUEST padtemplates can be reverse-parsed (the user asks for 'sink1', the
* 'sink%d' template is automatically selected), so we need to restrict their
* naming.
*/
static gboolean
name_is_valid (const gchar * name, GstPadPresence presence)
{
const gchar *str;
if (presence == GST_PAD_ALWAYS) {
if (strchr (name, '%')) {
g_warning ("invalid name template %s: conversion specifications are not"
" allowed for GST_PAD_ALWAYS padtemplates", name);
return FALSE;
}
} else if (presence == GST_PAD_REQUEST) {
if ((str = strchr (name, '%')) && strchr (str + 1, '%')) {
g_warning ("invalid name template %s: only one conversion specification"
" allowed in GST_PAD_REQUEST padtemplate", name);
return FALSE;
}
if (str && (*(str + 1) != 's' && *(str + 1) != 'd' && *(str + 1) != 'u')) {
g_warning ("invalid name template %s: conversion specification must be of"
" type '%%d', '%%u' or '%%s' for GST_PAD_REQUEST padtemplate", name);
return FALSE;
}
if (str && (*(str + 2) != '\0')) {
g_warning ("invalid name template %s: conversion specification must"
" appear at the end of the GST_PAD_REQUEST padtemplate name", name);
return FALSE;
}
}
return TRUE;
}
GType
gst_static_pad_template_get_type (void)
{
static GType staticpadtemplate_type = 0;
if (G_UNLIKELY (staticpadtemplate_type == 0)) {
staticpadtemplate_type =
g_pointer_type_register_static ("GstStaticPadTemplate");
}
return staticpadtemplate_type;
}
/**
* gst_static_pad_template_get:
* @pad_template: the static pad template
*
* Converts a #GstStaticPadTemplate into a #GstPadTemplate.
*
* Returns: a new #GstPadTemplate.
*/
GstPadTemplate *
gst_static_pad_template_get (GstStaticPadTemplate * pad_template)
{
GstPadTemplate *new;
GstCaps *caps;
if (!name_is_valid (pad_template->name_template, pad_template->presence))
return NULL;
caps = gst_static_caps_get (&pad_template->static_caps);
new = g_object_new (gst_pad_template_get_type (),
"name", pad_template->name_template,
"name-template", pad_template->name_template,
"direction", pad_template->direction,
"presence", pad_template->presence, "caps", caps, NULL);
gst_caps_unref (caps);
return new;
}
/**
* gst_pad_template_new:
* @name_template: the name template.
* @direction: the #GstPadDirection of the template.
* @presence: the #GstPadPresence of the pad.
* @caps: a #GstCaps set for the template. The caps are taken ownership of.
*
* Creates a new pad template with a name according to the given template
* and with the given arguments. This functions takes ownership of the provided
* caps, so be sure to not use them afterwards.
*
* Returns: a new #GstPadTemplate.
*/
GstPadTemplate *
gst_pad_template_new (const gchar * name_template,
GstPadDirection direction, GstPadPresence presence, GstCaps * caps)
{
GstPadTemplate *new;
g_return_val_if_fail (name_template != NULL, NULL);
g_return_val_if_fail (caps != NULL, NULL);
g_return_val_if_fail (direction == GST_PAD_SRC
|| direction == GST_PAD_SINK, NULL);
g_return_val_if_fail (presence == GST_PAD_ALWAYS
|| presence == GST_PAD_SOMETIMES || presence == GST_PAD_REQUEST, NULL);
if (!name_is_valid (name_template, presence)) {
gst_caps_unref (caps);
return NULL;
}
new = g_object_new (gst_pad_template_get_type (),
"name", name_template, "name-template", name_template,
"direction", direction, "presence", presence, "caps", caps, NULL);
if (caps)
gst_caps_unref (caps);
return new;
}
/**
* gst_static_pad_template_get_caps:
* @templ: a #GstStaticPadTemplate to get capabilities of.
*
* Gets the capabilities of the static pad template.
*
* Returns: the #GstCaps of the static pad template.
* Unref after usage. Since the core holds an additional
* ref to the returned caps, use gst_caps_make_writable()
* on the returned caps to modify it.
*/
GstCaps *
gst_static_pad_template_get_caps (GstStaticPadTemplate * templ)
{
g_return_val_if_fail (templ, NULL);
return (GstCaps *) gst_static_caps_get (&templ->static_caps);
}
/**
* gst_pad_template_get_caps:
* @templ: a #GstPadTemplate to get capabilities of.
*
* Gets the capabilities of the pad template.
*
* Returns: the #GstCaps of the pad template. If you need to keep a reference to
* the caps, take a ref (see gst_caps_ref ()).
*/
GstCaps *
gst_pad_template_get_caps (GstPadTemplate * templ)
{
g_return_val_if_fail (GST_IS_PAD_TEMPLATE (templ), NULL);
return GST_PAD_TEMPLATE_CAPS (templ);
}
/**
* gst_pad_template_pad_created:
* @templ: a #GstPadTemplate that has been created
* @pad: the #GstPad that created it
*
* Emit the pad-created signal for this template when created by this pad.
*/
void
gst_pad_template_pad_created (GstPadTemplate * templ, GstPad * pad)
{
g_signal_emit (templ, gst_pad_template_signals[TEMPL_PAD_CREATED], 0, pad);
}
static void
gst_pad_template_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec)
{
/* these properties are all construct-only */
switch (prop_id) {
case PROP_NAME_TEMPLATE:
GST_PAD_TEMPLATE_NAME_TEMPLATE (object) = g_value_dup_string (value);
break;
case PROP_DIRECTION:
GST_PAD_TEMPLATE_DIRECTION (object) = g_value_get_enum (value);
break;
case PROP_PRESENCE:
GST_PAD_TEMPLATE_PRESENCE (object) = g_value_get_enum (value);
break;
case PROP_CAPS:
/* allow caps == NULL for backwards compatibility (ie. g_object_new()
* called without any of the new properties) (FIXME 0.11) */
if (g_value_get_boxed (value) != NULL) {
GST_PAD_TEMPLATE_CAPS (object) =
gst_caps_copy (g_value_get_boxed (value));
}
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
gst_pad_template_get_property (GObject * object, guint prop_id, GValue * value,
GParamSpec * pspec)
{
/* these properties are all construct-only */
switch (prop_id) {
case PROP_NAME_TEMPLATE:
g_value_set_string (value, GST_PAD_TEMPLATE_NAME_TEMPLATE (object));
break;
case PROP_DIRECTION:
g_value_set_enum (value, GST_PAD_TEMPLATE_DIRECTION (object));
break;
case PROP_PRESENCE:
g_value_set_enum (value, GST_PAD_TEMPLATE_PRESENCE (object));
break;
case PROP_CAPS:
g_value_set_boxed (value, GST_PAD_TEMPLATE_CAPS (object));
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}