1/* GStreamer
2 * Copyright (C) 2004 Wim Taymans <[email protected]>
3 *
4 * gstbus.h: Header for GstBus subsystem
5 *
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Library General Public
8 * License as published by the Free Software Foundation; either
9 * version 2 of the License, or (at your option) any later version.
10 *
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Library General Public License for more details.
15 *
16 * You should have received a copy of the GNU Library General Public
17 * License along with this library; if not, write to the
18 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
19 * Boston, MA 02110-1301, USA.
20 */
21
22#ifndef __GST_BUS_H__
23#define __GST_BUS_H__
24
25typedef struct _GstBus GstBus;
26typedef struct _GstBusPrivate GstBusPrivate;
27typedef struct _GstBusClass GstBusClass;
28
29#include <gst/gstmessage.h>
30#include <gst/gstclock.h>
31
32G_BEGIN_DECLS
33
34/* --- standard type macros --- */
35#define GST_TYPE_BUS (gst_bus_get_type ())
36#define GST_BUS(bus) (G_TYPE_CHECK_INSTANCE_CAST ((bus), GST_TYPE_BUS, GstBus))
37#define GST_IS_BUS(bus) (G_TYPE_CHECK_INSTANCE_TYPE ((bus), GST_TYPE_BUS))
38#define GST_BUS_CLASS(bclass) (G_TYPE_CHECK_CLASS_CAST ((bclass), GST_TYPE_BUS, GstBusClass))
39#define GST_IS_BUS_CLASS(bclass) (G_TYPE_CHECK_CLASS_TYPE ((bclass), GST_TYPE_BUS))
40#define GST_BUS_GET_CLASS(bus) (G_TYPE_INSTANCE_GET_CLASS ((bus), GST_TYPE_BUS, GstBusClass))
41#define GST_BUS_CAST(bus) ((GstBus*)(bus))
42
43/**
44 * GstBusFlags:
45 * @GST_BUS_FLUSHING: The bus is currently dropping all messages
46 * @GST_BUS_FLAG_LAST: offset to define more flags
47 *
48 * The standard flags that a bus may have.
49 */
50typedef enum {
51 GST_BUS_FLUSHING = (GST_OBJECT_FLAG_LAST << 0),
52 /* padding */
53 GST_BUS_FLAG_LAST = (GST_OBJECT_FLAG_LAST << 1)
54} GstBusFlags;
55
56/**
57 * GstBusSyncReply:
58 * @GST_BUS_DROP: drop the message
59 * @GST_BUS_PASS: pass the message to the async queue
60 * @GST_BUS_ASYNC: pass message to async queue, continue if message is handled
61 *
62 * The result values for a GstBusSyncHandler.
63 */
64typedef enum
65{
66 GST_BUS_DROP = 0,
67 GST_BUS_PASS = 1,
68 GST_BUS_ASYNC = 2
69} GstBusSyncReply;
70
71/**
72 * GstBusSyncHandler:
73 * @bus: the #GstBus that sent the message
74 * @message: the #GstMessage
75 * @user_data: user data that has been given, when registering the handler
76 *
77 * Handler will be invoked synchronously, when a new message has been injected
78 * into the bus. This function is mostly used internally. Only one sync handler
79 * can be attached to a given bus.
80 *
81 * If the handler returns %GST_BUS_DROP, it should unref the message, else the
82 * message should not be unreffed by the sync handler.
83 *
84 * Returns: #GstBusSyncReply stating what to do with the message
85 */
86typedef GstBusSyncReply (*GstBusSyncHandler) (GstBus * bus, GstMessage * message, gpointer user_data);
87
88/**
89 * GstBusFunc:
90 * @bus: the #GstBus that sent the message
91 * @message: the #GstMessage
92 * @user_data: user data that has been given, when registering the handler
93 *
94 * Specifies the type of function passed to gst_bus_add_watch() or
95 * gst_bus_add_watch_full(), which is called from the mainloop when a message
96 * is available on the bus.
97 *
98 * The message passed to the function will be unreffed after execution of this
99 * function so it should not be freed in the function.
100 *
101 * Note that this function is used as a #GSourceFunc which means that returning
102 * %FALSE will remove the #GSource from the mainloop.
103 *
104 * Returns: %FALSE if the event source should be removed.
105 */
106typedef gboolean (*GstBusFunc) (GstBus * bus, GstMessage * message, gpointer user_data);
107
108/**
109 * GstBus:
110 * @object: the parent structure
111 *
112 * The opaque #GstBus data structure.
113 */
114struct _GstBus
115{
116 GstObject object;
117
118 /*< private >*/
119 GstBusPrivate *priv;
120
121 gpointer _gst_reserved[GST_PADDING];
122};
123
124/**
125 * GstBusClass:
126 * @parent_class: the parent class structure
127 *
128 * GStreamer bus class.
129 */
130struct _GstBusClass
131{
132 GstObjectClass parent_class;
133
134 /* signals */
135
136 /**
137 * GstBusClass::message:
138 * @bus: the #GstBus
139 * @message: the message that has been posted asynchronously
140 *
141 * A message has been posted on the bus.
142 */
143 void (*message) (GstBus *bus, GstMessage *message);
144
145 /**
146 * GstBusClass::sync_message:
147 * @bus: the #GstBus
148 * @message: the message that has been posted synchronously
149 *
150 * A message has been posted on the bus.
151 */
152 void (*sync_message) (GstBus *bus, GstMessage *message);
153
154 /*< private >*/
155 gpointer _gst_reserved[GST_PADDING];
156};
157
158GST_API
159GType gst_bus_get_type (void);
160
161GST_API
162GstBus* gst_bus_new (void);
163
164GST_API
165gboolean gst_bus_post (GstBus * bus, GstMessage * message);
166
167GST_API
168gboolean gst_bus_have_pending (GstBus * bus);
169
170GST_API
171GstMessage * gst_bus_peek (GstBus * bus);
172
173GST_API
174GstMessage * gst_bus_pop (GstBus * bus);
175
176GST_API
177GstMessage * gst_bus_pop_filtered (GstBus * bus, GstMessageType types);
178
179GST_API
180GstMessage * gst_bus_timed_pop (GstBus * bus, GstClockTime timeout);
181
182GST_API
183GstMessage * gst_bus_timed_pop_filtered (GstBus * bus, GstClockTime timeout, GstMessageType types);
184
185GST_API
186void gst_bus_set_flushing (GstBus * bus, gboolean flushing);
187
188/* synchronous dispatching */
189
190GST_API
191void gst_bus_set_sync_handler (GstBus * bus, GstBusSyncHandler func,
192 gpointer user_data, GDestroyNotify notify);
193
194/* asynchronous message notifications */
195
196GST_API
197void gst_bus_get_pollfd (GstBus * bus, GPollFD *fd);
198
199/* GSource based dispatching */
200
201GST_API
202GSource * gst_bus_create_watch (GstBus * bus);
203
204GST_API
205guint gst_bus_add_watch_full (GstBus * bus,
206 gint priority,
207 GstBusFunc func,
208 gpointer user_data,
209 GDestroyNotify notify);
210GST_API
211guint gst_bus_add_watch (GstBus * bus,
212 GstBusFunc func,
213 gpointer user_data);
214GST_API
215gboolean gst_bus_remove_watch (GstBus * bus);
216
217/* polling the bus */
218
219GST_API
220GstMessage* gst_bus_poll (GstBus *bus, GstMessageType events,
221 GstClockTime timeout);
222
223/* signal based dispatching helper functions. */
224
225GST_API
226gboolean gst_bus_async_signal_func (GstBus *bus, GstMessage *message,
227 gpointer data);
228GST_API
229GstBusSyncReply gst_bus_sync_signal_handler (GstBus *bus, GstMessage *message,
230 gpointer data);
231
232/* convenience api to add/remove a gsource that emits the async signals */
233
234GST_API
235void gst_bus_add_signal_watch (GstBus * bus);
236
237GST_API
238void gst_bus_add_signal_watch_full (GstBus * bus, gint priority);
239
240GST_API
241void gst_bus_remove_signal_watch (GstBus * bus);
242
243GST_API
244void gst_bus_enable_sync_message_emission (GstBus * bus);
245
246GST_API
247void gst_bus_disable_sync_message_emission (GstBus * bus);
248
249G_DEFINE_AUTOPTR_CLEANUP_FUNC(GstBus, gst_object_unref)
250
251G_END_DECLS
252
253#endif /* __GST_BUS_H__ */
254

source code of include/gstreamer-1.0/gst/gstbus.h