| /* GStreamer |
| * Copyright (C) 2005 Stefan Kost <ensonic@users.sf.net> |
| * |
| * gstchildproxy.c: interface for multi child elements |
| * |
| * 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:gstchildproxy |
| * @short_description: Interface for multi child elements. |
| * @see_also: #GstBin |
| * |
| * This interface abstracts handling of property sets for elements with |
| * children. Imagine elements such as mixers or polyphonic generators. They all |
| * have multiple #GstPad or some kind of voice objects. Another use case are |
| * container elements like #GstBin. |
| * The element implementing the interface acts as a parent for those child |
| * objects. |
| * |
| * By implementing this interface the child properties can be accessed from the |
| * parent element by using gst_child_proxy_get() and gst_child_proxy_set(). |
| * |
| * Property names are written as "child-name::property-name". The whole naming |
| * scheme is recursive. Thus "child1::child2::property" is valid too, if |
| * "child1" and "child2" implement the #GstChildProxy interface. |
| */ |
| /* FIXME-0.11: |
| * it would be nice to make gst_child_proxy_get_child_by_name virtual too and |
| * use GObject instead of GstObject. We could eventually provide the current |
| * implementation as a default if children are GstObjects. |
| * This change would allow to propose the interface for inclusion with |
| * glib/gobject. IMHO this is useful for GtkContainer and compound widgets too. |
| */ |
| |
| #include "gst_private.h" |
| |
| #include "gstchildproxy.h" |
| #include "gstmarshal.h" |
| #include <gobject/gvaluecollector.h> |
| |
| /* signals */ |
| enum |
| { |
| CHILD_ADDED, |
| CHILD_REMOVED, |
| LAST_SIGNAL |
| }; |
| |
| static guint signals[LAST_SIGNAL] = { 0 }; |
| |
| /** |
| * gst_child_proxy_get_child_by_name: |
| * @parent: the parent object to get the child from |
| * @name: the childs name |
| * |
| * Looks up a child element by the given name. |
| * |
| * Implementors can use #GstObject together with gst_object_get_name() |
| * |
| * Returns: the child object or %NULL if not found. Unref after usage. |
| * |
| * MT safe. |
| */ |
| GstObject * |
| gst_child_proxy_get_child_by_name (GstChildProxy * parent, const gchar * name) |
| { |
| guint count, i; |
| GstObject *object, *result; |
| gchar *object_name; |
| |
| g_return_val_if_fail (GST_IS_CHILD_PROXY (parent), NULL); |
| g_return_val_if_fail (name != NULL, NULL); |
| |
| result = NULL; |
| |
| count = gst_child_proxy_get_children_count (parent); |
| for (i = 0; i < count; i++) { |
| gboolean eq; |
| |
| if (!(object = gst_child_proxy_get_child_by_index (parent, i))) |
| continue; |
| |
| object_name = gst_object_get_name (object); |
| if (object_name == NULL) { |
| g_warning ("child %u of parent %s has no name", i, |
| GST_OBJECT_NAME (parent)); |
| goto next; |
| } |
| eq = g_str_equal (object_name, name); |
| g_free (object_name); |
| |
| if (eq) { |
| result = object; |
| break; |
| } |
| next: |
| gst_object_unref (object); |
| } |
| return result; |
| } |
| |
| /** |
| * gst_child_proxy_get_child_by_index: |
| * @parent: the parent object to get the child from |
| * @index: the childs position in the child list |
| * |
| * Fetches a child by its number. |
| * |
| * Returns: the child object or %NULL if not found (index too high). Unref |
| * after usage. |
| * |
| * MT safe. |
| */ |
| GstObject * |
| gst_child_proxy_get_child_by_index (GstChildProxy * parent, guint index) |
| { |
| g_return_val_if_fail (GST_IS_CHILD_PROXY (parent), NULL); |
| |
| return (GST_CHILD_PROXY_GET_INTERFACE (parent)->get_child_by_index (parent, |
| index)); |
| } |
| |
| /** |
| * gst_child_proxy_get_children_count: |
| * @parent: the parent object |
| * |
| * Gets the number of child objects this parent contains. |
| * |
| * Returns: the number of child objects |
| * |
| * MT safe. |
| */ |
| guint |
| gst_child_proxy_get_children_count (GstChildProxy * parent) |
| { |
| g_return_val_if_fail (GST_IS_CHILD_PROXY (parent), 0); |
| |
| return (GST_CHILD_PROXY_GET_INTERFACE (parent)->get_children_count (parent)); |
| } |
| |
| /** |
| * gst_child_proxy_lookup: |
| * @object: object to lookup the property in |
| * @name: name of the property to look up |
| * @target: pointer to a #GstObject that takes the real object to set property on |
| * @pspec: pointer to take the #GParamSpec describing the property |
| * |
| * Looks up which object and #GParamSpec would be effected by the given @name. |
| * |
| * Returns: TRUE if @target and @pspec could be found. FALSE otherwise. In that |
| * case the values for @pspec and @target are not modified. Unref @target after |
| * usage. |
| * |
| * MT safe. |
| */ |
| gboolean |
| gst_child_proxy_lookup (GstObject * object, const gchar * name, |
| GstObject ** target, GParamSpec ** pspec) |
| { |
| gboolean res = FALSE; |
| gchar **names, **current; |
| |
| g_return_val_if_fail (GST_IS_OBJECT (object), FALSE); |
| g_return_val_if_fail (name != NULL, FALSE); |
| |
| gst_object_ref (object); |
| |
| current = names = g_strsplit (name, "::", -1); |
| while (current[1]) { |
| GstObject *next; |
| |
| if (!GST_IS_CHILD_PROXY (object)) { |
| GST_INFO |
| ("object %s is not a parent, so you cannot request a child by name %s", |
| GST_OBJECT_NAME (object), current[0]); |
| break; |
| } |
| next = gst_child_proxy_get_child_by_name (GST_CHILD_PROXY (object), |
| current[0]); |
| if (!next) { |
| GST_INFO ("no such object %s", current[0]); |
| break; |
| } |
| gst_object_unref (object); |
| object = next; |
| current++; |
| } |
| if (current[1] == NULL) { |
| GParamSpec *spec = |
| g_object_class_find_property (G_OBJECT_GET_CLASS (object), current[0]); |
| if (spec == NULL) { |
| GST_INFO ("no param spec named %s", current[0]); |
| } else { |
| if (pspec) |
| *pspec = spec; |
| if (target) { |
| gst_object_ref (object); |
| *target = object; |
| } |
| res = TRUE; |
| } |
| } |
| gst_object_unref (object); |
| g_strfreev (names); |
| return res; |
| } |
| |
| /** |
| * gst_child_proxy_get_property: |
| * @object: object to query |
| * @name: name of the property |
| * @value: a #GValue that should take the result. |
| * |
| * Gets a single property using the GstChildProxy mechanism. |
| * You are responsible for for freeing it by calling g_value_unset() |
| */ |
| void |
| gst_child_proxy_get_property (GstObject * object, const gchar * name, |
| GValue * value) |
| { |
| GParamSpec *pspec; |
| GstObject *target; |
| |
| g_return_if_fail (GST_IS_OBJECT (object)); |
| g_return_if_fail (name != NULL); |
| g_return_if_fail (G_IS_VALUE (value)); |
| |
| if (!gst_child_proxy_lookup (object, name, &target, &pspec)) |
| goto not_found; |
| |
| g_object_get_property (G_OBJECT (target), pspec->name, value); |
| gst_object_unref (target); |
| |
| return; |
| |
| not_found: |
| { |
| g_warning ("no property %s in object %s", name, GST_OBJECT_NAME (object)); |
| return; |
| } |
| } |
| |
| /** |
| * gst_child_proxy_get_valist: |
| * @object: the object to query |
| * @first_property_name: name of the first property to get |
| * @var_args: return location for the first property, followed optionally by more name/return location pairs, followed by NULL |
| * |
| * Gets properties of the parent object and its children. |
| */ |
| void |
| gst_child_proxy_get_valist (GstObject * object, |
| const gchar * first_property_name, va_list var_args) |
| { |
| const gchar *name; |
| gchar *error = NULL; |
| GValue value = { 0, }; |
| GParamSpec *pspec; |
| GstObject *target; |
| |
| g_return_if_fail (G_IS_OBJECT (object)); |
| |
| name = first_property_name; |
| |
| /* iterate over pairs */ |
| while (name) { |
| if (!gst_child_proxy_lookup (object, name, &target, &pspec)) |
| goto not_found; |
| |
| g_value_init (&value, pspec->value_type); |
| g_object_get_property (G_OBJECT (target), pspec->name, &value); |
| gst_object_unref (target); |
| |
| G_VALUE_LCOPY (&value, var_args, 0, &error); |
| if (error) |
| goto cant_copy; |
| g_value_unset (&value); |
| name = va_arg (var_args, gchar *); |
| } |
| return; |
| |
| not_found: |
| { |
| g_warning ("no property %s in object %s", name, GST_OBJECT_NAME (object)); |
| return; |
| } |
| cant_copy: |
| { |
| g_warning ("error copying value %s in object %s: %s", pspec->name, |
| GST_OBJECT_NAME (object), error); |
| g_value_unset (&value); |
| return; |
| } |
| } |
| |
| /** |
| * gst_child_proxy_get: |
| * @object: the parent object |
| * @first_property_name: name of the first property to get |
| * @...: return location for the first property, followed optionally by more name/return location pairs, followed by NULL |
| * |
| * Gets properties of the parent object and its children. |
| */ |
| void |
| gst_child_proxy_get (GstObject * object, const gchar * first_property_name, ...) |
| { |
| va_list var_args; |
| |
| g_return_if_fail (GST_IS_OBJECT (object)); |
| |
| va_start (var_args, first_property_name); |
| gst_child_proxy_get_valist (object, first_property_name, var_args); |
| va_end (var_args); |
| } |
| |
| /** |
| * gst_child_proxy_set_property: |
| * @object: the parent object |
| * @name: name of the property to set |
| * @value: new #GValue for the property |
| * |
| * Sets a single property using the GstChildProxy mechanism. |
| */ |
| void |
| gst_child_proxy_set_property (GstObject * object, const gchar * name, |
| const GValue * value) |
| { |
| GParamSpec *pspec; |
| GstObject *target; |
| |
| g_return_if_fail (GST_IS_OBJECT (object)); |
| g_return_if_fail (name != NULL); |
| g_return_if_fail (G_IS_VALUE (value)); |
| |
| if (!gst_child_proxy_lookup (object, name, &target, &pspec)) |
| goto not_found; |
| |
| g_object_set_property (G_OBJECT (target), pspec->name, value); |
| gst_object_unref (target); |
| return; |
| |
| not_found: |
| { |
| g_warning ("cannot set property %s on object %s", name, |
| GST_OBJECT_NAME (object)); |
| return; |
| } |
| } |
| |
| /** |
| * gst_child_proxy_set_valist: |
| * @object: the parent object |
| * @first_property_name: name of the first property to set |
| * @var_args: value for the first property, followed optionally by more name/value pairs, followed by NULL |
| * |
| * Sets properties of the parent object and its children. |
| */ |
| void |
| gst_child_proxy_set_valist (GstObject * object, |
| const gchar * first_property_name, va_list var_args) |
| { |
| const gchar *name; |
| gchar *error = NULL; |
| GValue value = { 0, }; |
| GParamSpec *pspec; |
| GstObject *target; |
| |
| g_return_if_fail (G_IS_OBJECT (object)); |
| |
| name = first_property_name; |
| |
| /* iterate over pairs */ |
| while (name) { |
| if (!gst_child_proxy_lookup (object, name, &target, &pspec)) |
| goto not_found; |
| |
| #if GLIB_CHECK_VERSION(2,23,3) |
| G_VALUE_COLLECT_INIT (&value, pspec->value_type, var_args, |
| G_VALUE_NOCOPY_CONTENTS, &error); |
| #else |
| g_value_init (&value, G_PARAM_SPEC_VALUE_TYPE (pspec)); |
| G_VALUE_COLLECT (&value, var_args, G_VALUE_NOCOPY_CONTENTS, &error); |
| #endif |
| if (error) |
| goto cant_copy; |
| |
| g_object_set_property (G_OBJECT (target), pspec->name, &value); |
| gst_object_unref (target); |
| |
| g_value_unset (&value); |
| name = va_arg (var_args, gchar *); |
| } |
| return; |
| |
| not_found: |
| { |
| g_warning ("no property %s in object %s", name, GST_OBJECT_NAME (object)); |
| return; |
| } |
| cant_copy: |
| { |
| g_warning ("error copying value %s in object %s: %s", pspec->name, |
| GST_OBJECT_NAME (object), error); |
| g_value_unset (&value); |
| gst_object_unref (target); |
| return; |
| } |
| } |
| |
| /** |
| * gst_child_proxy_set: |
| * @object: the parent object |
| * @first_property_name: name of the first property to set |
| * @...: value for the first property, followed optionally by more name/value pairs, followed by NULL |
| * |
| * Sets properties of the parent object and its children. |
| */ |
| void |
| gst_child_proxy_set (GstObject * object, const gchar * first_property_name, ...) |
| { |
| va_list var_args; |
| |
| g_return_if_fail (GST_IS_OBJECT (object)); |
| |
| va_start (var_args, first_property_name); |
| gst_child_proxy_set_valist (object, first_property_name, var_args); |
| va_end (var_args); |
| } |
| |
| /** |
| * gst_child_proxy_child_added: |
| * @object: the parent object |
| * @child: the newly added child |
| * |
| * Emits the "child-added" signal. |
| */ |
| void |
| gst_child_proxy_child_added (GstObject * object, GstObject * child) |
| { |
| g_signal_emit (G_OBJECT (object), signals[CHILD_ADDED], 0, child); |
| } |
| |
| /** |
| * gst_child_proxy_child_removed: |
| * @object: the parent object |
| * @child: the removed child |
| * |
| * Emits the "child-removed" signal. |
| */ |
| void |
| gst_child_proxy_child_removed (GstObject * object, GstObject * child) |
| { |
| g_signal_emit (G_OBJECT (object), signals[CHILD_REMOVED], 0, child); |
| } |
| |
| /* gobject methods */ |
| |
| static void |
| gst_child_proxy_base_init (gpointer g_class) |
| { |
| static gboolean initialized = FALSE; |
| |
| if (!initialized) { |
| /* create interface signals and properties here. */ |
| /** |
| * GstChildProxy::child-added: |
| * @child_proxy: the #GstChildProxy |
| * @object: the #GObject that was added |
| * |
| * Will be emitted after the @object was added to the @child_proxy. |
| */ |
| /* FIXME 0.11: use GST_TYPE_OBJECT as GstChildProxy only |
| * supports GstObjects */ |
| signals[CHILD_ADDED] = |
| g_signal_new ("child-added", G_TYPE_FROM_CLASS (g_class), |
| G_SIGNAL_RUN_FIRST, G_STRUCT_OFFSET (GstChildProxyInterface, |
| child_added), NULL, NULL, gst_marshal_VOID__OBJECT, G_TYPE_NONE, 1, |
| G_TYPE_OBJECT); |
| |
| /** |
| * GstChildProxy::child-removed: |
| * @child_proxy: the #GstChildProxy |
| * @object: the #GObject that was removed |
| * |
| * Will be emitted after the @object was removed from the @child_proxy. |
| */ |
| /* FIXME 0.11: use GST_TYPE_OBJECT as GstChildProxy only |
| * supports GstObjects */ |
| signals[CHILD_REMOVED] = |
| g_signal_new ("child-removed", G_TYPE_FROM_CLASS (g_class), |
| G_SIGNAL_RUN_FIRST, G_STRUCT_OFFSET (GstChildProxyInterface, |
| child_removed), NULL, NULL, gst_marshal_VOID__OBJECT, G_TYPE_NONE, |
| 1, G_TYPE_OBJECT); |
| |
| initialized = TRUE; |
| } |
| } |
| |
| GType |
| gst_child_proxy_get_type (void) |
| { |
| static volatile gsize type = 0; |
| |
| if (g_once_init_enter (&type)) { |
| GType _type; |
| static const GTypeInfo info = { |
| sizeof (GstChildProxyInterface), |
| gst_child_proxy_base_init, /* base_init */ |
| NULL, /* base_finalize */ |
| NULL, /* class_init */ |
| NULL, /* class_finalize */ |
| NULL, /* class_data */ |
| 0, |
| 0, /* n_preallocs */ |
| NULL /* instance_init */ |
| }; |
| |
| _type = |
| g_type_register_static (G_TYPE_INTERFACE, "GstChildProxy", &info, 0); |
| |
| g_type_interface_add_prerequisite (_type, GST_TYPE_OBJECT); |
| g_once_init_leave (&type, (gsize) _type); |
| } |
| return type; |
| } |