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 *
111 * The opaque #GstBus data structure.
112 */
113struct _GstBus
114{
115 GstObject object;
116
117 /*< private >*/
118 GstBusPrivate *priv;
119
120 gpointer _gst_reserved[GST_PADDING];
121};
122
123struct _GstBusClass
124{
125 GstObjectClass parent_class;
126
127 /* signals */
128 void (*message) (GstBus *bus, GstMessage *message);
129 void (*sync_message) (GstBus *bus, GstMessage *message);
130
131 /*< private >*/
132 gpointer _gst_reserved[GST_PADDING];
133};
134
135GST_API
136GType gst_bus_get_type (void);
137
138GST_API
139GstBus* gst_bus_new (void);
140
141GST_API
142gboolean gst_bus_post (GstBus * bus, GstMessage * message);
143
144GST_API
145gboolean gst_bus_have_pending (GstBus * bus);
146
147GST_API
148GstMessage * gst_bus_peek (GstBus * bus);
149
150GST_API
151GstMessage * gst_bus_pop (GstBus * bus);
152
153GST_API
154GstMessage * gst_bus_pop_filtered (GstBus * bus, GstMessageType types);
155
156GST_API
157GstMessage * gst_bus_timed_pop (GstBus * bus, GstClockTime timeout);
158
159GST_API
160GstMessage * gst_bus_timed_pop_filtered (GstBus * bus, GstClockTime timeout, GstMessageType types);
161
162GST_API
163void gst_bus_set_flushing (GstBus * bus, gboolean flushing);
164
165/* synchronous dispatching */
166
167GST_API
168void gst_bus_set_sync_handler (GstBus * bus, GstBusSyncHandler func,
169 gpointer user_data, GDestroyNotify notify);
170
171/* asynchronous message notifications */
172
173GST_API
174void gst_bus_get_pollfd (GstBus * bus, GPollFD *fd);
175
176/* GSource based dispatching */
177
178GST_API
179GSource * gst_bus_create_watch (GstBus * bus);
180
181GST_API
182guint gst_bus_add_watch_full (GstBus * bus,
183 gint priority,
184 GstBusFunc func,
185 gpointer user_data,
186 GDestroyNotify notify);
187GST_API
188guint gst_bus_add_watch (GstBus * bus,
189 GstBusFunc func,
190 gpointer user_data);
191GST_API
192gboolean gst_bus_remove_watch (GstBus * bus);
193
194/* polling the bus */
195
196GST_API
197GstMessage* gst_bus_poll (GstBus *bus, GstMessageType events,
198 GstClockTime timeout);
199
200/* signal based dispatching helper functions. */
201
202GST_API
203gboolean gst_bus_async_signal_func (GstBus *bus, GstMessage *message,
204 gpointer data);
205GST_API
206GstBusSyncReply gst_bus_sync_signal_handler (GstBus *bus, GstMessage *message,
207 gpointer data);
208
209/* convenience api to add/remove a gsource that emits the async signals */
210
211GST_API
212void gst_bus_add_signal_watch (GstBus * bus);
213
214GST_API
215void gst_bus_add_signal_watch_full (GstBus * bus, gint priority);
216
217GST_API
218void gst_bus_remove_signal_watch (GstBus * bus);
219
220GST_API
221void gst_bus_enable_sync_message_emission (GstBus * bus);
222
223GST_API
224void gst_bus_disable_sync_message_emission (GstBus * bus);
225
226#ifdef G_DEFINE_AUTOPTR_CLEANUP_FUNC
227G_DEFINE_AUTOPTR_CLEANUP_FUNC(GstBus, gst_object_unref)
228#endif
229
230G_END_DECLS
231
232#endif /* __GST_BUS_H__ */
233