1/* GObject - GLib Type, Object, Parameter and Signal Library
2 * Copyright (C) 2000-2001 Red Hat, Inc.
3 *
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2 of the License, or (at your option) any later version.
8 *
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Lesser General Public License for more details.
13 *
14 * You should have received a copy of the GNU Lesser General
15 * Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
16 */
17#ifndef __G_SIGNAL_H__
18#define __G_SIGNAL_H__
19
20#if !defined (__GLIB_GOBJECT_H_INSIDE__) && !defined (GOBJECT_COMPILATION)
21#error "Only <glib-object.h> can be included directly."
22#endif
23
24#include <gobject/gclosure.h>
25#include <gobject/gvalue.h>
26#include <gobject/gparam.h>
27#include <gobject/gmarshal.h>
28
29G_BEGIN_DECLS
30
31/* --- typedefs --- */
32typedef struct _GSignalQuery GSignalQuery;
33typedef struct _GSignalInvocationHint GSignalInvocationHint;
34/**
35 * GSignalCMarshaller:
36 *
37 * This is the signature of marshaller functions, required to marshall
38 * arrays of parameter values to signal emissions into C language callback
39 * invocations. It is merely an alias to #GClosureMarshal since the #GClosure
40 * mechanism takes over responsibility of actual function invocation for the
41 * signal system.
42 */
43typedef GClosureMarshal GSignalCMarshaller;
44/**
45 * GSignalCVaMarshaller:
46 *
47 * This is the signature of va_list marshaller functions, an optional
48 * marshaller that can be used in some situations to avoid
49 * marshalling the signal argument into GValues.
50 */
51typedef GVaClosureMarshal GSignalCVaMarshaller;
52/**
53 * GSignalEmissionHook:
54 * @ihint: Signal invocation hint, see #GSignalInvocationHint.
55 * @n_param_values: the number of parameters to the function, including
56 * the instance on which the signal was emitted.
57 * @param_values: (array length=n_param_values): the instance on which
58 * the signal was emitted, followed by the parameters of the emission.
59 * @data: user data associated with the hook.
60 *
61 * A simple function pointer to get invoked when the signal is emitted. This
62 * allows you to tie a hook to the signal type, so that it will trap all
63 * emissions of that signal, from any object.
64 *
65 * You may not attach these to signals created with the #G_SIGNAL_NO_HOOKS flag.
66 *
67 * Returns: whether it wants to stay connected. If it returns %FALSE, the signal
68 * hook is disconnected (and destroyed).
69 */
70typedef gboolean (*GSignalEmissionHook) (GSignalInvocationHint *ihint,
71 guint n_param_values,
72 const GValue *param_values,
73 gpointer data);
74/**
75 * GSignalAccumulator:
76 * @ihint: Signal invocation hint, see #GSignalInvocationHint.
77 * @return_accu: Accumulator to collect callback return values in, this
78 * is the return value of the current signal emission.
79 * @handler_return: A #GValue holding the return value of the signal handler.
80 * @data: Callback data that was specified when creating the signal.
81 *
82 * The signal accumulator is a special callback function that can be used
83 * to collect return values of the various callbacks that are called
84 * during a signal emission. The signal accumulator is specified at signal
85 * creation time, if it is left %NULL, no accumulation of callback return
86 * values is performed. The return value of signal emissions is then the
87 * value returned by the last callback.
88 *
89 * Returns: The accumulator function returns whether the signal emission
90 * should be aborted. Returning %FALSE means to abort the
91 * current emission and %TRUE is returned for continuation.
92 */
93typedef gboolean (*GSignalAccumulator) (GSignalInvocationHint *ihint,
94 GValue *return_accu,
95 const GValue *handler_return,
96 gpointer data);
97
98
99/* --- run, match and connect types --- */
100/**
101 * GSignalFlags:
102 * @G_SIGNAL_RUN_FIRST: Invoke the object method handler in the first emission stage.
103 * @G_SIGNAL_RUN_LAST: Invoke the object method handler in the third emission stage.
104 * @G_SIGNAL_RUN_CLEANUP: Invoke the object method handler in the last emission stage.
105 * @G_SIGNAL_NO_RECURSE: Signals being emitted for an object while currently being in
106 * emission for this very object will not be emitted recursively,
107 * but instead cause the first emission to be restarted.
108 * @G_SIGNAL_DETAILED: This signal supports "::detail" appendices to the signal name
109 * upon handler connections and emissions.
110 * @G_SIGNAL_ACTION: Action signals are signals that may freely be emitted on alive
111 * objects from user code via g_signal_emit() and friends, without
112 * the need of being embedded into extra code that performs pre or
113 * post emission adjustments on the object. They can also be thought
114 * of as object methods which can be called generically by
115 * third-party code.
116 * @G_SIGNAL_NO_HOOKS: No emissions hooks are supported for this signal.
117 * @G_SIGNAL_MUST_COLLECT: Varargs signal emission will always collect the
118 * arguments, even if there are no signal handlers connected. Since 2.30.
119 * @G_SIGNAL_DEPRECATED: The signal is deprecated and will be removed
120 * in a future version. A warning will be generated if it is connected while
121 * running with G_ENABLE_DIAGNOSTIC=1. Since 2.32.
122 *
123 * The signal flags are used to specify a signal's behaviour, the overall
124 * signal description outlines how especially the RUN flags control the
125 * stages of a signal emission.
126 */
127typedef enum
128{
129 G_SIGNAL_RUN_FIRST = 1 << 0,
130 G_SIGNAL_RUN_LAST = 1 << 1,
131 G_SIGNAL_RUN_CLEANUP = 1 << 2,
132 G_SIGNAL_NO_RECURSE = 1 << 3,
133 G_SIGNAL_DETAILED = 1 << 4,
134 G_SIGNAL_ACTION = 1 << 5,
135 G_SIGNAL_NO_HOOKS = 1 << 6,
136 G_SIGNAL_MUST_COLLECT = 1 << 7,
137 G_SIGNAL_DEPRECATED = 1 << 8
138} GSignalFlags;
139/**
140 * G_SIGNAL_FLAGS_MASK:
141 *
142 * A mask for all #GSignalFlags bits.
143 */
144#define G_SIGNAL_FLAGS_MASK 0x1ff
145/**
146 * GConnectFlags:
147 * @G_CONNECT_AFTER: whether the handler should be called before or after the
148 * default handler of the signal.
149 * @G_CONNECT_SWAPPED: whether the instance and data should be swapped when
150 * calling the handler; see g_signal_connect_swapped() for an example.
151 *
152 * The connection flags are used to specify the behaviour of a signal's
153 * connection.
154 */
155typedef enum
156{
157 G_CONNECT_AFTER = 1 << 0,
158 G_CONNECT_SWAPPED = 1 << 1
159} GConnectFlags;
160/**
161 * GSignalMatchType:
162 * @G_SIGNAL_MATCH_ID: The signal id must be equal.
163 * @G_SIGNAL_MATCH_DETAIL: The signal detail be equal.
164 * @G_SIGNAL_MATCH_CLOSURE: The closure must be the same.
165 * @G_SIGNAL_MATCH_FUNC: The C closure callback must be the same.
166 * @G_SIGNAL_MATCH_DATA: The closure data must be the same.
167 * @G_SIGNAL_MATCH_UNBLOCKED: Only unblocked signals may matched.
168 *
169 * The match types specify what g_signal_handlers_block_matched(),
170 * g_signal_handlers_unblock_matched() and g_signal_handlers_disconnect_matched()
171 * match signals by.
172 */
173typedef enum
174{
175 G_SIGNAL_MATCH_ID = 1 << 0,
176 G_SIGNAL_MATCH_DETAIL = 1 << 1,
177 G_SIGNAL_MATCH_CLOSURE = 1 << 2,
178 G_SIGNAL_MATCH_FUNC = 1 << 3,
179 G_SIGNAL_MATCH_DATA = 1 << 4,
180 G_SIGNAL_MATCH_UNBLOCKED = 1 << 5
181} GSignalMatchType;
182/**
183 * G_SIGNAL_MATCH_MASK:
184 *
185 * A mask for all #GSignalMatchType bits.
186 */
187#define G_SIGNAL_MATCH_MASK 0x3f
188/**
189 * G_SIGNAL_TYPE_STATIC_SCOPE:
190 *
191 * This macro flags signal argument types for which the signal system may
192 * assume that instances thereof remain persistent across all signal emissions
193 * they are used in. This is only useful for non ref-counted, value-copy types.
194 *
195 * To flag a signal argument in this way, add `| G_SIGNAL_TYPE_STATIC_SCOPE`
196 * to the corresponding argument of g_signal_new().
197 * |[
198 * g_signal_new ("size_request",
199 * G_TYPE_FROM_CLASS (gobject_class),
200 * G_SIGNAL_RUN_FIRST,
201 * G_STRUCT_OFFSET (GtkWidgetClass, size_request),
202 * NULL, NULL,
203 * _gtk_marshal_VOID__BOXED,
204 * G_TYPE_NONE, 1,
205 * GTK_TYPE_REQUISITION | G_SIGNAL_TYPE_STATIC_SCOPE);
206 * ]|
207 */
208#define G_SIGNAL_TYPE_STATIC_SCOPE (G_TYPE_FLAG_RESERVED_ID_BIT)
209
210
211/* --- signal information --- */
212/**
213 * GSignalInvocationHint:
214 * @signal_id: The signal id of the signal invoking the callback
215 * @detail: The detail passed on for this emission
216 * @run_type: The stage the signal emission is currently in, this
217 * field will contain one of %G_SIGNAL_RUN_FIRST,
218 * %G_SIGNAL_RUN_LAST or %G_SIGNAL_RUN_CLEANUP.
219 *
220 * The #GSignalInvocationHint structure is used to pass on additional information
221 * to callbacks during a signal emission.
222 */
223struct _GSignalInvocationHint
224{
225 guint signal_id;
226 GQuark detail;
227 GSignalFlags run_type;
228};
229/**
230 * GSignalQuery:
231 * @signal_id: The signal id of the signal being queried, or 0 if the
232 * signal to be queried was unknown.
233 * @signal_name: The signal name.
234 * @itype: The interface/instance type that this signal can be emitted for.
235 * @signal_flags: The signal flags as passed in to g_signal_new().
236 * @return_type: The return type for user callbacks.
237 * @n_params: The number of parameters that user callbacks take.
238 * @param_types: (array length=n_params): The individual parameter types for
239 * user callbacks, note that the effective callback signature is:
240 * |[<!-- language="C" -->
241 * @return_type callback (#gpointer data1,
242 * [param_types param_names,]
243 * gpointer data2);
244 * ]|
245 *
246 * A structure holding in-depth information for a specific signal. It is
247 * filled in by the g_signal_query() function.
248 */
249struct _GSignalQuery
250{
251 guint signal_id;
252 const gchar *signal_name;
253 GType itype;
254 GSignalFlags signal_flags;
255 GType return_type; /* mangled with G_SIGNAL_TYPE_STATIC_SCOPE flag */
256 guint n_params;
257 const GType *param_types; /* mangled with G_SIGNAL_TYPE_STATIC_SCOPE flag */
258};
259
260
261/* --- signals --- */
262GLIB_AVAILABLE_IN_ALL
263guint g_signal_newv (const gchar *signal_name,
264 GType itype,
265 GSignalFlags signal_flags,
266 GClosure *class_closure,
267 GSignalAccumulator accumulator,
268 gpointer accu_data,
269 GSignalCMarshaller c_marshaller,
270 GType return_type,
271 guint n_params,
272 GType *param_types);
273GLIB_AVAILABLE_IN_ALL
274guint g_signal_new_valist (const gchar *signal_name,
275 GType itype,
276 GSignalFlags signal_flags,
277 GClosure *class_closure,
278 GSignalAccumulator accumulator,
279 gpointer accu_data,
280 GSignalCMarshaller c_marshaller,
281 GType return_type,
282 guint n_params,
283 va_list args);
284GLIB_AVAILABLE_IN_ALL
285guint g_signal_new (const gchar *signal_name,
286 GType itype,
287 GSignalFlags signal_flags,
288 guint class_offset,
289 GSignalAccumulator accumulator,
290 gpointer accu_data,
291 GSignalCMarshaller c_marshaller,
292 GType return_type,
293 guint n_params,
294 ...);
295GLIB_AVAILABLE_IN_ALL
296guint g_signal_new_class_handler (const gchar *signal_name,
297 GType itype,
298 GSignalFlags signal_flags,
299 GCallback class_handler,
300 GSignalAccumulator accumulator,
301 gpointer accu_data,
302 GSignalCMarshaller c_marshaller,
303 GType return_type,
304 guint n_params,
305 ...);
306GLIB_AVAILABLE_IN_ALL
307void g_signal_set_va_marshaller (guint signal_id,
308 GType instance_type,
309 GSignalCVaMarshaller va_marshaller);
310
311GLIB_AVAILABLE_IN_ALL
312void g_signal_emitv (const GValue *instance_and_params,
313 guint signal_id,
314 GQuark detail,
315 GValue *return_value);
316GLIB_AVAILABLE_IN_ALL
317void g_signal_emit_valist (gpointer instance,
318 guint signal_id,
319 GQuark detail,
320 va_list var_args);
321GLIB_AVAILABLE_IN_ALL
322void g_signal_emit (gpointer instance,
323 guint signal_id,
324 GQuark detail,
325 ...);
326GLIB_AVAILABLE_IN_ALL
327void g_signal_emit_by_name (gpointer instance,
328 const gchar *detailed_signal,
329 ...);
330GLIB_AVAILABLE_IN_ALL
331guint g_signal_lookup (const gchar *name,
332 GType itype);
333GLIB_AVAILABLE_IN_ALL
334const gchar * g_signal_name (guint signal_id);
335GLIB_AVAILABLE_IN_ALL
336void g_signal_query (guint signal_id,
337 GSignalQuery *query);
338GLIB_AVAILABLE_IN_ALL
339guint* g_signal_list_ids (GType itype,
340 guint *n_ids);
341GLIB_AVAILABLE_IN_ALL
342gboolean g_signal_parse_name (const gchar *detailed_signal,
343 GType itype,
344 guint *signal_id_p,
345 GQuark *detail_p,
346 gboolean force_detail_quark);
347GLIB_AVAILABLE_IN_ALL
348GSignalInvocationHint* g_signal_get_invocation_hint (gpointer instance);
349
350
351/* --- signal emissions --- */
352GLIB_AVAILABLE_IN_ALL
353void g_signal_stop_emission (gpointer instance,
354 guint signal_id,
355 GQuark detail);
356GLIB_AVAILABLE_IN_ALL
357void g_signal_stop_emission_by_name (gpointer instance,
358 const gchar *detailed_signal);
359GLIB_AVAILABLE_IN_ALL
360gulong g_signal_add_emission_hook (guint signal_id,
361 GQuark detail,
362 GSignalEmissionHook hook_func,
363 gpointer hook_data,
364 GDestroyNotify data_destroy);
365GLIB_AVAILABLE_IN_ALL
366void g_signal_remove_emission_hook (guint signal_id,
367 gulong hook_id);
368
369
370/* --- signal handlers --- */
371GLIB_AVAILABLE_IN_ALL
372gboolean g_signal_has_handler_pending (gpointer instance,
373 guint signal_id,
374 GQuark detail,
375 gboolean may_be_blocked);
376GLIB_AVAILABLE_IN_ALL
377gulong g_signal_connect_closure_by_id (gpointer instance,
378 guint signal_id,
379 GQuark detail,
380 GClosure *closure,
381 gboolean after);
382GLIB_AVAILABLE_IN_ALL
383gulong g_signal_connect_closure (gpointer instance,
384 const gchar *detailed_signal,
385 GClosure *closure,
386 gboolean after);
387GLIB_AVAILABLE_IN_ALL
388gulong g_signal_connect_data (gpointer instance,
389 const gchar *detailed_signal,
390 GCallback c_handler,
391 gpointer data,
392 GClosureNotify destroy_data,
393 GConnectFlags connect_flags);
394GLIB_AVAILABLE_IN_ALL
395void g_signal_handler_block (gpointer instance,
396 gulong handler_id);
397GLIB_AVAILABLE_IN_ALL
398void g_signal_handler_unblock (gpointer instance,
399 gulong handler_id);
400GLIB_AVAILABLE_IN_ALL
401void g_signal_handler_disconnect (gpointer instance,
402 gulong handler_id);
403GLIB_AVAILABLE_IN_ALL
404gboolean g_signal_handler_is_connected (gpointer instance,
405 gulong handler_id);
406GLIB_AVAILABLE_IN_ALL
407gulong g_signal_handler_find (gpointer instance,
408 GSignalMatchType mask,
409 guint signal_id,
410 GQuark detail,
411 GClosure *closure,
412 gpointer func,
413 gpointer data);
414GLIB_AVAILABLE_IN_ALL
415guint g_signal_handlers_block_matched (gpointer instance,
416 GSignalMatchType mask,
417 guint signal_id,
418 GQuark detail,
419 GClosure *closure,
420 gpointer func,
421 gpointer data);
422GLIB_AVAILABLE_IN_ALL
423guint g_signal_handlers_unblock_matched (gpointer instance,
424 GSignalMatchType mask,
425 guint signal_id,
426 GQuark detail,
427 GClosure *closure,
428 gpointer func,
429 gpointer data);
430GLIB_AVAILABLE_IN_ALL
431guint g_signal_handlers_disconnect_matched (gpointer instance,
432 GSignalMatchType mask,
433 guint signal_id,
434 GQuark detail,
435 GClosure *closure,
436 gpointer func,
437 gpointer data);
438
439
440/* --- overriding and chaining --- */
441GLIB_AVAILABLE_IN_ALL
442void g_signal_override_class_closure (guint signal_id,
443 GType instance_type,
444 GClosure *class_closure);
445GLIB_AVAILABLE_IN_ALL
446void g_signal_override_class_handler (const gchar *signal_name,
447 GType instance_type,
448 GCallback class_handler);
449GLIB_AVAILABLE_IN_ALL
450void g_signal_chain_from_overridden (const GValue *instance_and_params,
451 GValue *return_value);
452GLIB_AVAILABLE_IN_ALL
453void g_signal_chain_from_overridden_handler (gpointer instance,
454 ...);
455
456
457/* --- convenience --- */
458/**
459 * g_signal_connect:
460 * @instance: the instance to connect to.
461 * @detailed_signal: a string of the form "signal-name::detail".
462 * @c_handler: the #GCallback to connect.
463 * @data: data to pass to @c_handler calls.
464 *
465 * Connects a #GCallback function to a signal for a particular object.
466 *
467 * The handler will be called before the default handler of the signal.
468 *
469 * See [memory management of signal handlers][signal-memory-management] for
470 * details on how to handle the return value and memory management of @data.
471 *
472 * Returns: the handler id (always greater than 0 for successful connections)
473 */
474#define g_signal_connect(instance, detailed_signal, c_handler, data) \
475 g_signal_connect_data ((instance), (detailed_signal), (c_handler), (data), NULL, (GConnectFlags) 0)
476/**
477 * g_signal_connect_after:
478 * @instance: the instance to connect to.
479 * @detailed_signal: a string of the form "signal-name::detail".
480 * @c_handler: the #GCallback to connect.
481 * @data: data to pass to @c_handler calls.
482 *
483 * Connects a #GCallback function to a signal for a particular object.
484 *
485 * The handler will be called after the default handler of the signal.
486 *
487 * Returns: the handler id (always greater than 0 for successful connections)
488 */
489#define g_signal_connect_after(instance, detailed_signal, c_handler, data) \
490 g_signal_connect_data ((instance), (detailed_signal), (c_handler), (data), NULL, G_CONNECT_AFTER)
491/**
492 * g_signal_connect_swapped:
493 * @instance: the instance to connect to.
494 * @detailed_signal: a string of the form "signal-name::detail".
495 * @c_handler: the #GCallback to connect.
496 * @data: data to pass to @c_handler calls.
497 *
498 * Connects a #GCallback function to a signal for a particular object.
499 *
500 * The instance on which the signal is emitted and @data will be swapped when
501 * calling the handler. This is useful when calling pre-existing functions to
502 * operate purely on the @data, rather than the @instance: swapping the
503 * parameters avoids the need to write a wrapper function.
504 *
505 * For example, this allows the shorter code:
506 * |[<!-- language="C" -->
507 * g_signal_connect_swapped (button, "clicked",
508 * (GCallback) gtk_widget_hide, other_widget);
509 * ]|
510 *
511 * Rather than the cumbersome:
512 * |[<!-- language="C" -->
513 * static void
514 * button_clicked_cb (GtkButton *button, GtkWidget *other_widget)
515 * {
516 * gtk_widget_hide (other_widget);
517 * }
518 *
519 * …
520 *
521 * g_signal_connect (button, "clicked",
522 * (GCallback) button_clicked_cb, other_widget);
523 * ]|
524 *
525 * Returns: the handler ID (always greater than 0 for successful connections)
526 */
527#define g_signal_connect_swapped(instance, detailed_signal, c_handler, data) \
528 g_signal_connect_data ((instance), (detailed_signal), (c_handler), (data), NULL, G_CONNECT_SWAPPED)
529/**
530 * g_signal_handlers_disconnect_by_func:
531 * @instance: The instance to remove handlers from.
532 * @func: The C closure callback of the handlers (useless for non-C closures).
533 * @data: The closure data of the handlers' closures.
534 *
535 * Disconnects all handlers on an instance that match @func and @data.
536 *
537 * Returns: The number of handlers that matched.
538 */
539#define g_signal_handlers_disconnect_by_func(instance, func, data) \
540 g_signal_handlers_disconnect_matched ((instance), \
541 (GSignalMatchType) (G_SIGNAL_MATCH_FUNC | G_SIGNAL_MATCH_DATA), \
542 0, 0, NULL, (func), (data))
543
544/**
545 * g_signal_handlers_disconnect_by_data:
546 * @instance: The instance to remove handlers from
547 * @data: the closure data of the handlers' closures
548 *
549 * Disconnects all handlers on an instance that match @data.
550 *
551 * Returns: The number of handlers that matched.
552 *
553 * Since: 2.32
554 */
555#define g_signal_handlers_disconnect_by_data(instance, data) \
556 g_signal_handlers_disconnect_matched ((instance), G_SIGNAL_MATCH_DATA, 0, 0, NULL, NULL, (data))
557
558/**
559 * g_signal_handlers_block_by_func:
560 * @instance: The instance to block handlers from.
561 * @func: The C closure callback of the handlers (useless for non-C closures).
562 * @data: The closure data of the handlers' closures.
563 *
564 * Blocks all handlers on an instance that match @func and @data.
565 *
566 * Returns: The number of handlers that matched.
567 */
568#define g_signal_handlers_block_by_func(instance, func, data) \
569 g_signal_handlers_block_matched ((instance), \
570 (GSignalMatchType) (G_SIGNAL_MATCH_FUNC | G_SIGNAL_MATCH_DATA), \
571 0, 0, NULL, (func), (data))
572/**
573 * g_signal_handlers_unblock_by_func:
574 * @instance: The instance to unblock handlers from.
575 * @func: The C closure callback of the handlers (useless for non-C closures).
576 * @data: The closure data of the handlers' closures.
577 *
578 * Unblocks all handlers on an instance that match @func and @data.
579 *
580 * Returns: The number of handlers that matched.
581 */
582#define g_signal_handlers_unblock_by_func(instance, func, data) \
583 g_signal_handlers_unblock_matched ((instance), \
584 (GSignalMatchType) (G_SIGNAL_MATCH_FUNC | G_SIGNAL_MATCH_DATA), \
585 0, 0, NULL, (func), (data))
586
587
588GLIB_AVAILABLE_IN_ALL
589gboolean g_signal_accumulator_true_handled (GSignalInvocationHint *ihint,
590 GValue *return_accu,
591 const GValue *handler_return,
592 gpointer dummy);
593
594GLIB_AVAILABLE_IN_ALL
595gboolean g_signal_accumulator_first_wins (GSignalInvocationHint *ihint,
596 GValue *return_accu,
597 const GValue *handler_return,
598 gpointer dummy);
599
600/*< private >*/
601GLIB_AVAILABLE_IN_ALL
602void g_signal_handlers_destroy (gpointer instance);
603void _g_signals_destroy (GType itype);
604
605G_END_DECLS
606
607#endif /* __G_SIGNAL_H__ */
608