/* GStreamer * Copyright (C) 1999,2000 Erik Walthinsen * 2000 Wim Taymans * * 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_request_pad_by_name() * 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. * * Create a pad from a padtemplate * * 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"); * ... * } * * * * 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: * * * 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)); * } * * * * 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 (templ); gst_object_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. If you need to keep a * reference to the caps, take a ref (see gst_caps_ref ()). */ 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 (G_OBJECT (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; } }