1 /* GLIB - Library of useful routines for C programming
2 * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
3 *
4 * gmain.c: Main loop abstraction, timeouts, and idle functions
5 * Copyright 1998 Owen Taylor
6 *
7 * This library is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * This library is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with this library; if not, see <http://www.gnu.org/licenses/>.
19 */
20
21 /*
22 * Modified by the GLib Team and others 1997-2000. See the AUTHORS
23 * file for a list of people on the GLib Team. See the ChangeLog
24 * files for a list of changes. These files are distributed with
25 * GLib at ftp://ftp.gtk.org/pub/gtk/.
26 */
27
28 /*
29 * MT safe
30 */
31
32 #include "config.h"
33 #include "glibconfig.h"
34 #include "glib_trace.h"
35
36 /* Uncomment the next line (and the corresponding line in gpoll.c) to
37 * enable debugging printouts if the environment variable
38 * G_MAIN_POLL_DEBUG is set to some value.
39 */
40 /* #define G_MAIN_POLL_DEBUG */
41
42 #ifdef _WIN32
43 /* Always enable debugging printout on Windows, as it is more often
44 * needed there...
45 */
46 #define G_MAIN_POLL_DEBUG
47 #endif
48
49 #ifdef G_OS_UNIX
50 #include "glib-unix.h"
51 #include <pthread.h>
52 #ifdef HAVE_EVENTFD
53 #include <sys/eventfd.h>
54 #endif
55 #endif
56
57 #include <signal.h>
58 #include <sys/types.h>
59 #include <time.h>
60 #include <stdlib.h>
61 #ifdef HAVE_SYS_TIME_H
62 #include <sys/time.h>
63 #endif /* HAVE_SYS_TIME_H */
64 #ifdef G_OS_UNIX
65 #include <unistd.h>
66 #endif /* G_OS_UNIX */
67 #include <errno.h>
68 #include <string.h>
69
70 #ifdef G_OS_WIN32
71 #define STRICT
72 #include <windows.h>
73 #endif /* G_OS_WIN32 */
74
75 #ifdef HAVE_MACH_MACH_TIME_H
76 #include <mach/mach_time.h>
77 #endif
78
79 #include "glib_trace.h"
80
81 #include "gmain.h"
82
83 #include "garray.h"
84 #include "giochannel.h"
85 #include "ghash.h"
86 #include "ghook.h"
87 #include "gqueue.h"
88 #include "gstrfuncs.h"
89 #include "gtestutils.h"
90 #include "gthreadprivate.h"
91 #include "gtrace-private.h"
92
93 #ifdef G_OS_WIN32
94 #include "gwin32.h"
95 #endif
96
97 #ifdef G_MAIN_POLL_DEBUG
98 #include "gtimer.h"
99 #endif
100
101 #include "gwakeup.h"
102 #include "gmain-internal.h"
103 #include "glib-init.h"
104 #include "glib-private.h"
105
106 /**
107 * SECTION:main
108 * @title: The Main Event Loop
109 * @short_description: manages all available sources of events
110 *
111 * The main event loop manages all the available sources of events for
112 * GLib and GTK+ applications. These events can come from any number of
113 * different types of sources such as file descriptors (plain files,
114 * pipes or sockets) and timeouts. New types of event sources can also
115 * be added using g_source_attach().
116 *
117 * To allow multiple independent sets of sources to be handled in
118 * different threads, each source is associated with a #GMainContext.
119 * A #GMainContext can only be running in a single thread, but
120 * sources can be added to it and removed from it from other threads. All
121 * functions which operate on a #GMainContext or a built-in #GSource are
122 * thread-safe.
123 *
124 * Each event source is assigned a priority. The default priority,
125 * %G_PRIORITY_DEFAULT, is 0. Values less than 0 denote higher priorities.
126 * Values greater than 0 denote lower priorities. Events from high priority
127 * sources are always processed before events from lower priority sources.
128 *
129 * Idle functions can also be added, and assigned a priority. These will
130 * be run whenever no events with a higher priority are ready to be processed.
131 *
132 * The #GMainLoop data type represents a main event loop. A GMainLoop is
133 * created with g_main_loop_new(). After adding the initial event sources,
134 * g_main_loop_run() is called. This continuously checks for new events from
135 * each of the event sources and dispatches them. Finally, the processing of
136 * an event from one of the sources leads to a call to g_main_loop_quit() to
137 * exit the main loop, and g_main_loop_run() returns.
138 *
139 * It is possible to create new instances of #GMainLoop recursively.
140 * This is often used in GTK+ applications when showing modal dialog
141 * boxes. Note that event sources are associated with a particular
142 * #GMainContext, and will be checked and dispatched for all main
143 * loops associated with that GMainContext.
144 *
145 * GTK+ contains wrappers of some of these functions, e.g. gtk_main(),
146 * gtk_main_quit() and gtk_events_pending().
147 *
148 * ## Creating new source types
149 *
150 * One of the unusual features of the #GMainLoop functionality
151 * is that new types of event source can be created and used in
152 * addition to the builtin type of event source. A new event source
153 * type is used for handling GDK events. A new source type is created
154 * by "deriving" from the #GSource structure. The derived type of
155 * source is represented by a structure that has the #GSource structure
156 * as a first element, and other elements specific to the new source
157 * type. To create an instance of the new source type, call
158 * g_source_new() passing in the size of the derived structure and
159 * a table of functions. These #GSourceFuncs determine the behavior of
160 * the new source type.
161 *
162 * New source types basically interact with the main context
163 * in two ways. Their prepare function in #GSourceFuncs can set a timeout
164 * to determine the maximum amount of time that the main loop will sleep
165 * before checking the source again. In addition, or as well, the source
166 * can add file descriptors to the set that the main context checks using
167 * g_source_add_poll().
168 *
169 * ## Customizing the main loop iteration
170 *
171 * Single iterations of a #GMainContext can be run with
172 * g_main_context_iteration(). In some cases, more detailed control
173 * of exactly how the details of the main loop work is desired, for
174 * instance, when integrating the #GMainLoop with an external main loop.
175 * In such cases, you can call the component functions of
176 * g_main_context_iteration() directly. These functions are
177 * g_main_context_prepare(), g_main_context_query(),
178 * g_main_context_check() and g_main_context_dispatch().
179 *
180 * ## State of a Main Context # {#mainloop-states}
181 *
182 * The operation of these functions can best be seen in terms
183 * of a state diagram, as shown in this image.
184 *
185 * ![](mainloop-states.gif)
186 *
187 * On UNIX, the GLib mainloop is incompatible with fork(). Any program
188 * using the mainloop must either exec() or exit() from the child
189 * without returning to the mainloop.
190 *
191 * ## Memory management of sources # {#mainloop-memory-management}
192 *
193 * There are two options for memory management of the user data passed to a
194 * #GSource to be passed to its callback on invocation. This data is provided
195 * in calls to g_timeout_add(), g_timeout_add_full(), g_idle_add(), etc. and
196 * more generally, using g_source_set_callback(). This data is typically an
197 * object which ‘owns’ the timeout or idle callback, such as a widget or a
198 * network protocol implementation. In many cases, it is an error for the
199 * callback to be invoked after this owning object has been destroyed, as that
200 * results in use of freed memory.
201 *
202 * The first, and preferred, option is to store the source ID returned by
203 * functions such as g_timeout_add() or g_source_attach(), and explicitly
204 * remove that source from the main context using g_source_remove() when the
205 * owning object is finalized. This ensures that the callback can only be
206 * invoked while the object is still alive.
207 *
208 * The second option is to hold a strong reference to the object in the
209 * callback, and to release it in the callback’s #GDestroyNotify. This ensures
210 * that the object is kept alive until after the source is finalized, which is
211 * guaranteed to be after it is invoked for the final time. The #GDestroyNotify
212 * is another callback passed to the ‘full’ variants of #GSource functions (for
213 * example, g_timeout_add_full()). It is called when the source is finalized,
214 * and is designed for releasing references like this.
215 *
216 * One important caveat of this second approach is that it will keep the object
217 * alive indefinitely if the main loop is stopped before the #GSource is
218 * invoked, which may be undesirable.
219 */
220
221 /* Types */
222
223 typedef struct _GTimeoutSource GTimeoutSource;
224 typedef struct _GChildWatchSource GChildWatchSource;
225 typedef struct _GUnixSignalWatchSource GUnixSignalWatchSource;
226 typedef struct _GPollRec GPollRec;
227 typedef struct _GSourceCallback GSourceCallback;
228
229 typedef enum
230 {
231 G_SOURCE_READY = 1 << G_HOOK_FLAG_USER_SHIFT,
232 G_SOURCE_CAN_RECURSE = 1 << (G_HOOK_FLAG_USER_SHIFT + 1),
233 G_SOURCE_BLOCKED = 1 << (G_HOOK_FLAG_USER_SHIFT + 2)
234 } GSourceFlags;
235
236 typedef struct _GSourceList GSourceList;
237
238 struct _GSourceList
239 {
240 GSource *head, *tail;
241 gint priority;
242 };
243
244 typedef struct _GMainWaiter GMainWaiter;
245
246 struct _GMainWaiter
247 {
248 GCond *cond;
249 GMutex *mutex;
250 };
251
252 typedef struct _GMainDispatch GMainDispatch;
253
254 struct _GMainDispatch
255 {
256 gint depth;
257 GSource *source;
258 };
259
260 #ifdef G_MAIN_POLL_DEBUG
261 gboolean _g_main_poll_debug = FALSE;
262 #endif
263
264 struct _GMainContext
265 {
266 /* The following lock is used for both the list of sources
267 * and the list of poll records
268 */
269 GMutex mutex;
270 GCond cond;
271 GThread *owner;
272 guint owner_count;
273 GSList *waiters;
274
275 gint ref_count; /* (atomic) */
276
277 GHashTable *sources; /* guint -> GSource */
278
279 GPtrArray *pending_dispatches;
280 gint timeout; /* Timeout for current iteration */
281
282 guint next_id;
283 GList *source_lists;
284 gint in_check_or_prepare;
285
286 GPollRec *poll_records;
287 guint n_poll_records;
288 GPollFD *cached_poll_array;
289 guint cached_poll_array_size;
290
291 GWakeup *wakeup;
292
293 GPollFD wake_up_rec;
294
295 /* Flag indicating whether the set of fd's changed during a poll */
296 gboolean poll_changed;
297
298 GPollFunc poll_func;
299
300 gint64 time;
301 gboolean time_is_fresh;
302 };
303
304 struct _GSourceCallback
305 {
306 gint ref_count; /* (atomic) */
307 GSourceFunc func;
308 gpointer data;
309 GDestroyNotify notify;
310 };
311
312 struct _GMainLoop
313 {
314 GMainContext *context;
315 gboolean is_running; /* (atomic) */
316 gint ref_count; /* (atomic) */
317 };
318
319 struct _GTimeoutSource
320 {
321 GSource source;
322 /* Measured in seconds if 'seconds' is TRUE, or milliseconds otherwise. */
323 guint interval;
324 gboolean seconds;
325 };
326
327 struct _GChildWatchSource
328 {
329 GSource source;
330 GPid pid;
331 gint child_status;
332 #ifdef G_OS_WIN32
333 GPollFD poll;
334 #else /* G_OS_WIN32 */
335 gboolean child_exited; /* (atomic) */
336 #endif /* G_OS_WIN32 */
337 };
338
339 struct _GUnixSignalWatchSource
340 {
341 GSource source;
342 int signum;
343 gboolean pending; /* (atomic) */
344 };
345
346 struct _GPollRec
347 {
348 GPollFD *fd;
349 GPollRec *prev;
350 GPollRec *next;
351 gint priority;
352 };
353
354 struct _GSourcePrivate
355 {
356 GSList *child_sources;
357 GSource *parent_source;
358
359 gint64 ready_time;
360
361 /* This is currently only used on UNIX, but we always declare it (and
362 * let it remain empty on Windows) to avoid #ifdef all over the place.
363 */
364 GSList *fds;
365
366 GSourceDisposeFunc dispose;
367
368 gboolean static_name;
369 };
370
371 typedef struct _GSourceIter
372 {
373 GMainContext *context;
374 gboolean may_modify;
375 GList *current_list;
376 GSource *source;
377 } GSourceIter;
378
379 #define LOCK_CONTEXT(context) g_mutex_lock (&context->mutex)
380 #define UNLOCK_CONTEXT(context) g_mutex_unlock (&context->mutex)
381 #define G_THREAD_SELF g_thread_self ()
382
383 #define SOURCE_DESTROYED(source) (((source)->flags & G_HOOK_FLAG_ACTIVE) == 0)
384 #define SOURCE_BLOCKED(source) (((source)->flags & G_SOURCE_BLOCKED) != 0)
385
386 /* Forward declarations */
387
388 static void g_source_unref_internal (GSource *source,
389 GMainContext *context,
390 gboolean have_lock);
391 static void g_source_destroy_internal (GSource *source,
392 GMainContext *context,
393 gboolean have_lock);
394 static void g_source_set_priority_unlocked (GSource *source,
395 GMainContext *context,
396 gint priority);
397 static void g_child_source_remove_internal (GSource *child_source,
398 GMainContext *context);
399
400 static void g_main_context_poll (GMainContext *context,
401 gint timeout,
402 gint priority,
403 GPollFD *fds,
404 gint n_fds);
405 static void g_main_context_add_poll_unlocked (GMainContext *context,
406 gint priority,
407 GPollFD *fd);
408 static void g_main_context_remove_poll_unlocked (GMainContext *context,
409 GPollFD *fd);
410
411 static void g_source_iter_init (GSourceIter *iter,
412 GMainContext *context,
413 gboolean may_modify);
414 static gboolean g_source_iter_next (GSourceIter *iter,
415 GSource **source);
416 static void g_source_iter_clear (GSourceIter *iter);
417
418 static gboolean g_timeout_dispatch (GSource *source,
419 GSourceFunc callback,
420 gpointer user_data);
421 static gboolean g_child_watch_prepare (GSource *source,
422 gint *timeout);
423 static gboolean g_child_watch_check (GSource *source);
424 static gboolean g_child_watch_dispatch (GSource *source,
425 GSourceFunc callback,
426 gpointer user_data);
427 static void g_child_watch_finalize (GSource *source);
428 #ifdef G_OS_UNIX
429 static void g_unix_signal_handler (int signum);
430 static gboolean g_unix_signal_watch_prepare (GSource *source,
431 gint *timeout);
432 static gboolean g_unix_signal_watch_check (GSource *source);
433 static gboolean g_unix_signal_watch_dispatch (GSource *source,
434 GSourceFunc callback,
435 gpointer user_data);
436 static void g_unix_signal_watch_finalize (GSource *source);
437 #endif
438 static gboolean g_idle_prepare (GSource *source,
439 gint *timeout);
440 static gboolean g_idle_check (GSource *source);
441 static gboolean g_idle_dispatch (GSource *source,
442 GSourceFunc callback,
443 gpointer user_data);
444
445 static void block_source (GSource *source);
446
447 static GMainContext *glib_worker_context;
448
449 #ifndef G_OS_WIN32
450
451
452 /* UNIX signals work by marking one of these variables then waking the
453 * worker context to check on them and dispatch accordingly.
454 *
455 * Both variables must be accessed using atomic primitives, unless those atomic
456 * primitives are implemented using fallback mutexes (as those aren’t safe in
457 * an interrupt context).
458 *
459 * If using atomic primitives, the variables must be of type `int` (so they’re
460 * the right size for the atomic primitives). Otherwise, use `sig_atomic_t` if
461 * it’s available, which is guaranteed to be async-signal-safe (but it’s *not*
462 * guaranteed to be thread-safe, which is why we use atomic primitives if
463 * possible).
464 *
465 * Typically, `sig_atomic_t` is a typedef to `int`, but that’s not the case on
466 * FreeBSD, so we can’t use it unconditionally if it’s defined.
467 */
468 #if (defined(G_ATOMIC_LOCK_FREE) && defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)) || !defined(HAVE_SIG_ATOMIC_T)
469 static volatile int unix_signal_pending[NSIG];
470 static volatile int any_unix_signal_pending;
471 #else
472 static volatile sig_atomic_t unix_signal_pending[NSIG];
473 static volatile sig_atomic_t any_unix_signal_pending;
474 #endif
475
476 /* Guards all the data below */
477 G_LOCK_DEFINE_STATIC (unix_signal_lock);
478 static guint unix_signal_refcount[NSIG];
479 static GSList *unix_signal_watches;
480 static GSList *unix_child_watches;
481
482 GSourceFuncs g_unix_signal_funcs =
483 {
484 g_unix_signal_watch_prepare,
485 g_unix_signal_watch_check,
486 g_unix_signal_watch_dispatch,
487 g_unix_signal_watch_finalize,
488 NULL, NULL
489 };
490 #endif /* !G_OS_WIN32 */
491 G_LOCK_DEFINE_STATIC (main_context_list);
492 static GSList *main_context_list = NULL;
493
494 GSourceFuncs g_timeout_funcs =
495 {
496 NULL, /* prepare */
497 NULL, /* check */
498 g_timeout_dispatch,
499 NULL, NULL, NULL
500 };
501
502 GSourceFuncs g_child_watch_funcs =
503 {
504 g_child_watch_prepare,
505 g_child_watch_check,
506 g_child_watch_dispatch,
507 g_child_watch_finalize,
508 NULL, NULL
509 };
510
511 GSourceFuncs g_idle_funcs =
512 {
513 g_idle_prepare,
514 g_idle_check,
515 g_idle_dispatch,
516 NULL, NULL, NULL
517 };
518
519 /**
520 * g_main_context_ref:
521 * @context: a #GMainContext
522 *
523 * Increases the reference count on a #GMainContext object by one.
524 *
525 * Returns: the @context that was passed in (since 2.6)
526 **/
527 GMainContext *
g_main_context_ref(GMainContext * context)528 g_main_context_ref (GMainContext *context)
529 {
530 g_return_val_if_fail (context != NULL, NULL);
531 g_return_val_if_fail (g_atomic_int_get (&context->ref_count) > 0, NULL);
532
533 g_atomic_int_inc (&context->ref_count);
534
535 return context;
536 }
537
538 static inline void
poll_rec_list_free(GMainContext * context,GPollRec * list)539 poll_rec_list_free (GMainContext *context,
540 GPollRec *list)
541 {
542 g_slice_free_chain (GPollRec, list, next);
543 }
544
545 /**
546 * g_main_context_unref:
547 * @context: a #GMainContext
548 *
549 * Decreases the reference count on a #GMainContext object by one. If
550 * the result is zero, free the context and free all associated memory.
551 **/
552 void
g_main_context_unref(GMainContext * context)553 g_main_context_unref (GMainContext *context)
554 {
555 GSourceIter iter;
556 GSource *source;
557 GList *sl_iter;
558 GSList *s_iter, *remaining_sources = NULL;
559 GSourceList *list;
560 guint i;
561
562 g_return_if_fail (context != NULL);
563 g_return_if_fail (g_atomic_int_get (&context->ref_count) > 0);
564
565 if (!g_atomic_int_dec_and_test (&context->ref_count))
566 return;
567
568 G_LOCK (main_context_list);
569 main_context_list = g_slist_remove (main_context_list, context);
570 G_UNLOCK (main_context_list);
571
572 /* Free pending dispatches */
573 for (i = 0; i < context->pending_dispatches->len; i++)
574 g_source_unref_internal (context->pending_dispatches->pdata[i], context, FALSE);
575
576 /* g_source_iter_next() assumes the context is locked. */
577 LOCK_CONTEXT (context);
578
579 /* First collect all remaining sources from the sources lists and store a
580 * new reference in a separate list. Also set the context of the sources
581 * to NULL so that they can't access a partially destroyed context anymore.
582 *
583 * We have to do this first so that we have a strong reference to all
584 * sources and destroying them below does not also free them, and so that
585 * none of the sources can access the context from their finalize/dispose
586 * functions. */
587 g_source_iter_init (&iter, context, FALSE);
588 while (g_source_iter_next (&iter, &source))
589 {
590 source->context = NULL;
591 remaining_sources = g_slist_prepend (remaining_sources, g_source_ref (source));
592 }
593 g_source_iter_clear (&iter);
594
595 /* Next destroy all sources. As we still hold a reference to all of them,
596 * this won't cause any of them to be freed yet and especially prevents any
597 * source that unrefs another source from its finalize function to be freed.
598 */
599 for (s_iter = remaining_sources; s_iter; s_iter = s_iter->next)
600 {
601 source = s_iter->data;
602 g_source_destroy_internal (source, context, TRUE);
603 }
604
605 for (sl_iter = context->source_lists; sl_iter; sl_iter = sl_iter->next)
606 {
607 list = sl_iter->data;
608 g_slice_free (GSourceList, list);
609 }
610 g_list_free (context->source_lists);
611
612 g_hash_table_destroy (context->sources);
613
614 UNLOCK_CONTEXT (context);
615 g_mutex_clear (&context->mutex);
616
617 g_ptr_array_free (context->pending_dispatches, TRUE);
618 g_free (context->cached_poll_array);
619
620 poll_rec_list_free (context, context->poll_records);
621
622 g_wakeup_free (context->wakeup);
623 g_cond_clear (&context->cond);
624
625 g_free (context);
626
627 /* And now finally get rid of our references to the sources. This will cause
628 * them to be freed unless something else still has a reference to them. Due
629 * to setting the context pointers in the sources to NULL above, this won't
630 * ever access the context or the internal linked list inside the GSource.
631 * We already removed the sources completely from the context above. */
632 for (s_iter = remaining_sources; s_iter; s_iter = s_iter->next)
633 {
634 source = s_iter->data;
635 g_source_unref_internal (source, NULL, FALSE);
636 }
637 g_slist_free (remaining_sources);
638 }
639
640 /* Helper function used by mainloop/overflow test.
641 */
642 GMainContext *
g_main_context_new_with_next_id(guint next_id)643 g_main_context_new_with_next_id (guint next_id)
644 {
645 GMainContext *ret = g_main_context_new ();
646
647 ret->next_id = next_id;
648
649 return ret;
650 }
651
652 /**
653 * g_main_context_new:
654 *
655 * Creates a new #GMainContext structure.
656 *
657 * Returns: the new #GMainContext
658 **/
659 GMainContext *
g_main_context_new(void)660 g_main_context_new (void)
661 {
662 static gsize initialised;
663 GMainContext *context;
664
665 if (g_once_init_enter (&initialised))
666 {
667 #ifdef G_MAIN_POLL_DEBUG
668 if (g_getenv ("G_MAIN_POLL_DEBUG") != NULL)
669 _g_main_poll_debug = TRUE;
670 #endif
671
672 g_once_init_leave (&initialised, TRUE);
673 }
674
675 context = g_new0 (GMainContext, 1);
676
677 TRACE (GLIB_MAIN_CONTEXT_NEW (context));
678
679 g_mutex_init (&context->mutex);
680 g_cond_init (&context->cond);
681
682 context->sources = g_hash_table_new (NULL, NULL);
683 context->owner = NULL;
684 context->waiters = NULL;
685
686 context->ref_count = 1;
687
688 context->next_id = 1;
689
690 context->source_lists = NULL;
691
692 context->poll_func = g_poll;
693
694 context->cached_poll_array = NULL;
695 context->cached_poll_array_size = 0;
696
697 context->pending_dispatches = g_ptr_array_new ();
698
699 context->time_is_fresh = FALSE;
700
701 context->wakeup = g_wakeup_new ();
702 g_wakeup_get_pollfd (context->wakeup, &context->wake_up_rec);
703 g_main_context_add_poll_unlocked (context, 0, &context->wake_up_rec);
704
705 G_LOCK (main_context_list);
706 main_context_list = g_slist_append (main_context_list, context);
707
708 #ifdef G_MAIN_POLL_DEBUG
709 if (_g_main_poll_debug)
710 g_print ("created context=%p\n", context);
711 #endif
712
713 G_UNLOCK (main_context_list);
714
715 return context;
716 }
717
718 /**
719 * g_main_context_default:
720 *
721 * Returns the global default main context. This is the main context
722 * used for main loop functions when a main loop is not explicitly
723 * specified, and corresponds to the "main" main loop. See also
724 * g_main_context_get_thread_default().
725 *
726 * Returns: (transfer none): the global default main context.
727 **/
728 GMainContext *
g_main_context_default(void)729 g_main_context_default (void)
730 {
731 static GMainContext *default_main_context = NULL;
732
733 if (g_once_init_enter (&default_main_context))
734 {
735 GMainContext *context;
736
737 context = g_main_context_new ();
738
739 TRACE (GLIB_MAIN_CONTEXT_DEFAULT (context));
740
741 #ifdef G_MAIN_POLL_DEBUG
742 if (_g_main_poll_debug)
743 g_print ("default context=%p\n", context);
744 #endif
745
746 g_once_init_leave (&default_main_context, context);
747 }
748
749 return default_main_context;
750 }
751
752 static void
free_context(gpointer data)753 free_context (gpointer data)
754 {
755 GMainContext *context = data;
756
757 TRACE (GLIB_MAIN_CONTEXT_FREE (context));
758
759 g_main_context_release (context);
760 if (context)
761 g_main_context_unref (context);
762 }
763
764 static void
free_context_stack(gpointer data)765 free_context_stack (gpointer data)
766 {
767 g_queue_free_full((GQueue *) data, (GDestroyNotify) free_context);
768 }
769
770 static GPrivate thread_context_stack = G_PRIVATE_INIT (free_context_stack);
771
772 /**
773 * g_main_context_push_thread_default:
774 * @context: (nullable): a #GMainContext, or %NULL for the global default context
775 *
776 * Acquires @context and sets it as the thread-default context for the
777 * current thread. This will cause certain asynchronous operations
778 * (such as most [gio][gio]-based I/O) which are
779 * started in this thread to run under @context and deliver their
780 * results to its main loop, rather than running under the global
781 * default context in the main thread. Note that calling this function
782 * changes the context returned by g_main_context_get_thread_default(),
783 * not the one returned by g_main_context_default(), so it does not affect
784 * the context used by functions like g_idle_add().
785 *
786 * Normally you would call this function shortly after creating a new
787 * thread, passing it a #GMainContext which will be run by a
788 * #GMainLoop in that thread, to set a new default context for all
789 * async operations in that thread. In this case you may not need to
790 * ever call g_main_context_pop_thread_default(), assuming you want the
791 * new #GMainContext to be the default for the whole lifecycle of the
792 * thread.
793 *
794 * If you don't have control over how the new thread was created (e.g.
795 * in the new thread isn't newly created, or if the thread life
796 * cycle is managed by a #GThreadPool), it is always suggested to wrap
797 * the logic that needs to use the new #GMainContext inside a
798 * g_main_context_push_thread_default() / g_main_context_pop_thread_default()
799 * pair, otherwise threads that are re-used will end up never explicitly
800 * releasing the #GMainContext reference they hold.
801 *
802 * In some cases you may want to schedule a single operation in a
803 * non-default context, or temporarily use a non-default context in
804 * the main thread. In that case, you can wrap the call to the
805 * asynchronous operation inside a
806 * g_main_context_push_thread_default() /
807 * g_main_context_pop_thread_default() pair, but it is up to you to
808 * ensure that no other asynchronous operations accidentally get
809 * started while the non-default context is active.
810 *
811 * Beware that libraries that predate this function may not correctly
812 * handle being used from a thread with a thread-default context. Eg,
813 * see g_file_supports_thread_contexts().
814 *
815 * Since: 2.22
816 **/
817 void
g_main_context_push_thread_default(GMainContext * context)818 g_main_context_push_thread_default (GMainContext *context)
819 {
820 GQueue *stack;
821 gboolean acquired_context;
822
823 acquired_context = g_main_context_acquire (context);
824 g_return_if_fail (acquired_context);
825
826 if (context == g_main_context_default ())
827 context = NULL;
828 else if (context)
829 g_main_context_ref (context);
830
831 stack = g_private_get (&thread_context_stack);
832 if (!stack)
833 {
834 stack = g_queue_new ();
835 g_private_set (&thread_context_stack, stack);
836 }
837
838 g_queue_push_head (stack, context);
839
840 TRACE (GLIB_MAIN_CONTEXT_PUSH_THREAD_DEFAULT (context));
841 }
842
843 /**
844 * g_main_context_pop_thread_default:
845 * @context: (nullable): a #GMainContext object, or %NULL
846 *
847 * Pops @context off the thread-default context stack (verifying that
848 * it was on the top of the stack).
849 *
850 * Since: 2.22
851 **/
852 void
g_main_context_pop_thread_default(GMainContext * context)853 g_main_context_pop_thread_default (GMainContext *context)
854 {
855 GQueue *stack;
856
857 if (context == g_main_context_default ())
858 context = NULL;
859
860 stack = g_private_get (&thread_context_stack);
861
862 g_return_if_fail (stack != NULL);
863 g_return_if_fail (g_queue_peek_head (stack) == context);
864
865 TRACE (GLIB_MAIN_CONTEXT_POP_THREAD_DEFAULT (context));
866
867 g_queue_pop_head (stack);
868
869 g_main_context_release (context);
870 if (context)
871 g_main_context_unref (context);
872 }
873
874 /**
875 * g_main_context_get_thread_default:
876 *
877 * Gets the thread-default #GMainContext for this thread. Asynchronous
878 * operations that want to be able to be run in contexts other than
879 * the default one should call this method or
880 * g_main_context_ref_thread_default() to get a #GMainContext to add
881 * their #GSources to. (Note that even in single-threaded
882 * programs applications may sometimes want to temporarily push a
883 * non-default context, so it is not safe to assume that this will
884 * always return %NULL if you are running in the default thread.)
885 *
886 * If you need to hold a reference on the context, use
887 * g_main_context_ref_thread_default() instead.
888 *
889 * Returns: (transfer none) (nullable): the thread-default #GMainContext, or
890 * %NULL if the thread-default context is the global default context.
891 *
892 * Since: 2.22
893 **/
894 GMainContext *
g_main_context_get_thread_default(void)895 g_main_context_get_thread_default (void)
896 {
897 GQueue *stack;
898
899 stack = g_private_get (&thread_context_stack);
900 if (stack)
901 return g_queue_peek_head (stack);
902 else
903 return NULL;
904 }
905
906 /**
907 * g_main_context_ref_thread_default:
908 *
909 * Gets the thread-default #GMainContext for this thread, as with
910 * g_main_context_get_thread_default(), but also adds a reference to
911 * it with g_main_context_ref(). In addition, unlike
912 * g_main_context_get_thread_default(), if the thread-default context
913 * is the global default context, this will return that #GMainContext
914 * (with a ref added to it) rather than returning %NULL.
915 *
916 * Returns: (transfer full): the thread-default #GMainContext. Unref
917 * with g_main_context_unref() when you are done with it.
918 *
919 * Since: 2.32
920 */
921 GMainContext *
g_main_context_ref_thread_default(void)922 g_main_context_ref_thread_default (void)
923 {
924 GMainContext *context;
925
926 context = g_main_context_get_thread_default ();
927 if (!context)
928 context = g_main_context_default ();
929 return g_main_context_ref (context);
930 }
931
932 /* Hooks for adding to the main loop */
933
934 /**
935 * g_source_new:
936 * @source_funcs: structure containing functions that implement
937 * the sources behavior.
938 * @struct_size: size of the #GSource structure to create.
939 *
940 * Creates a new #GSource structure. The size is specified to
941 * allow creating structures derived from #GSource that contain
942 * additional data. The size passed in must be at least
943 * `sizeof (GSource)`.
944 *
945 * The source will not initially be associated with any #GMainContext
946 * and must be added to one with g_source_attach() before it will be
947 * executed.
948 *
949 * Returns: the newly-created #GSource.
950 **/
951 GSource *
g_source_new(GSourceFuncs * source_funcs,guint struct_size)952 g_source_new (GSourceFuncs *source_funcs,
953 guint struct_size)
954 {
955 GSource *source;
956
957 g_return_val_if_fail (source_funcs != NULL, NULL);
958 g_return_val_if_fail (struct_size >= sizeof (GSource), NULL);
959
960 source = (GSource*) g_malloc0 (struct_size);
961 source->priv = g_slice_new0 (GSourcePrivate);
962 source->source_funcs = source_funcs;
963 source->ref_count = 1;
964
965 source->priority = G_PRIORITY_DEFAULT;
966
967 source->flags = G_HOOK_FLAG_ACTIVE;
968
969 source->priv->ready_time = -1;
970
971 /* NULL/0 initialization for all other fields */
972
973 TRACE (GLIB_SOURCE_NEW (source, source_funcs->prepare, source_funcs->check,
974 source_funcs->dispatch, source_funcs->finalize,
975 struct_size));
976
977 return source;
978 }
979
980 /**
981 * g_source_set_dispose_function:
982 * @source: A #GSource to set the dispose function on
983 * @dispose: #GSourceDisposeFunc to set on the source
984 *
985 * Set @dispose as dispose function on @source. @dispose will be called once
986 * the reference count of @source reaches 0 but before any of the state of the
987 * source is freed, especially before the finalize function is called.
988 *
989 * This means that at this point @source is still a valid #GSource and it is
990 * allow for the reference count to increase again until @dispose returns.
991 *
992 * The dispose function can be used to clear any "weak" references to the
993 * @source in other data structures in a thread-safe way where it is possible
994 * for another thread to increase the reference count of @source again while
995 * it is being freed.
996 *
997 * The finalize function can not be used for this purpose as at that point
998 * @source is already partially freed and not valid anymore.
999 *
1000 * This should only ever be called from #GSource implementations.
1001 *
1002 * Since: 2.64
1003 **/
1004 void
g_source_set_dispose_function(GSource * source,GSourceDisposeFunc dispose)1005 g_source_set_dispose_function (GSource *source,
1006 GSourceDisposeFunc dispose)
1007 {
1008 g_return_if_fail (source != NULL);
1009 g_return_if_fail (source->priv->dispose == NULL);
1010 g_return_if_fail (g_atomic_int_get (&source->ref_count) > 0);
1011 source->priv->dispose = dispose;
1012 }
1013
1014 /* Holds context's lock */
1015 static void
g_source_iter_init(GSourceIter * iter,GMainContext * context,gboolean may_modify)1016 g_source_iter_init (GSourceIter *iter,
1017 GMainContext *context,
1018 gboolean may_modify)
1019 {
1020 iter->context = context;
1021 iter->current_list = NULL;
1022 iter->source = NULL;
1023 iter->may_modify = may_modify;
1024 }
1025
1026 /* Holds context's lock */
1027 static gboolean
g_source_iter_next(GSourceIter * iter,GSource ** source)1028 g_source_iter_next (GSourceIter *iter, GSource **source)
1029 {
1030 GSource *next_source;
1031
1032 if (iter->source)
1033 next_source = iter->source->next;
1034 else
1035 next_source = NULL;
1036
1037 if (!next_source)
1038 {
1039 if (iter->current_list)
1040 iter->current_list = iter->current_list->next;
1041 else
1042 iter->current_list = iter->context->source_lists;
1043
1044 if (iter->current_list)
1045 {
1046 GSourceList *source_list = iter->current_list->data;
1047
1048 next_source = source_list->head;
1049 }
1050 }
1051
1052 /* Note: unreffing iter->source could potentially cause its
1053 * GSourceList to be removed from source_lists (if iter->source is
1054 * the only source in its list, and it is destroyed), so we have to
1055 * keep it reffed until after we advance iter->current_list, above.
1056 *
1057 * Also we first have to ref the next source before unreffing the
1058 * previous one as unreffing the previous source can potentially
1059 * free the next one.
1060 */
1061 if (next_source && iter->may_modify)
1062 g_source_ref (next_source);
1063
1064 if (iter->source && iter->may_modify)
1065 g_source_unref_internal (iter->source, iter->context, TRUE);
1066 iter->source = next_source;
1067
1068 *source = iter->source;
1069 return *source != NULL;
1070 }
1071
1072 /* Holds context's lock. Only necessary to call if you broke out of
1073 * the g_source_iter_next() loop early.
1074 */
1075 static void
g_source_iter_clear(GSourceIter * iter)1076 g_source_iter_clear (GSourceIter *iter)
1077 {
1078 if (iter->source && iter->may_modify)
1079 {
1080 g_source_unref_internal (iter->source, iter->context, TRUE);
1081 iter->source = NULL;
1082 }
1083 }
1084
1085 /* Holds context's lock
1086 */
1087 static GSourceList *
find_source_list_for_priority(GMainContext * context,gint priority,gboolean create)1088 find_source_list_for_priority (GMainContext *context,
1089 gint priority,
1090 gboolean create)
1091 {
1092 GList *iter, *last;
1093 GSourceList *source_list;
1094
1095 last = NULL;
1096 for (iter = context->source_lists; iter != NULL; last = iter, iter = iter->next)
1097 {
1098 source_list = iter->data;
1099
1100 if (source_list->priority == priority)
1101 return source_list;
1102
1103 if (source_list->priority > priority)
1104 {
1105 if (!create)
1106 return NULL;
1107
1108 source_list = g_slice_new0 (GSourceList);
1109 source_list->priority = priority;
1110 context->source_lists = g_list_insert_before (context->source_lists,
1111 iter,
1112 source_list);
1113 return source_list;
1114 }
1115 }
1116
1117 if (!create)
1118 return NULL;
1119
1120 source_list = g_slice_new0 (GSourceList);
1121 source_list->priority = priority;
1122
1123 if (!last)
1124 context->source_lists = g_list_append (NULL, source_list);
1125 else
1126 {
1127 /* This just appends source_list to the end of
1128 * context->source_lists without having to walk the list again.
1129 */
1130 last = g_list_append (last, source_list);
1131 (void) last;
1132 }
1133 return source_list;
1134 }
1135
1136 /* Holds context's lock
1137 */
1138 static void
source_add_to_context(GSource * source,GMainContext * context)1139 source_add_to_context (GSource *source,
1140 GMainContext *context)
1141 {
1142 GSourceList *source_list;
1143 GSource *prev, *next;
1144
1145 source_list = find_source_list_for_priority (context, source->priority, TRUE);
1146
1147 if (source->priv->parent_source)
1148 {
1149 g_assert (source_list->head != NULL);
1150
1151 /* Put the source immediately before its parent */
1152 prev = source->priv->parent_source->prev;
1153 next = source->priv->parent_source;
1154 }
1155 else
1156 {
1157 prev = source_list->tail;
1158 next = NULL;
1159 }
1160
1161 source->next = next;
1162 if (next)
1163 next->prev = source;
1164 else
1165 source_list->tail = source;
1166
1167 source->prev = prev;
1168 if (prev)
1169 prev->next = source;
1170 else
1171 source_list->head = source;
1172 }
1173
1174 /* Holds context's lock
1175 */
1176 static void
source_remove_from_context(GSource * source,GMainContext * context)1177 source_remove_from_context (GSource *source,
1178 GMainContext *context)
1179 {
1180 GSourceList *source_list;
1181
1182 source_list = find_source_list_for_priority (context, source->priority, FALSE);
1183 g_return_if_fail (source_list != NULL);
1184
1185 if (source->prev)
1186 source->prev->next = source->next;
1187 else
1188 source_list->head = source->next;
1189
1190 if (source->next)
1191 source->next->prev = source->prev;
1192 else
1193 source_list->tail = source->prev;
1194
1195 source->prev = NULL;
1196 source->next = NULL;
1197
1198 if (source_list->head == NULL)
1199 {
1200 context->source_lists = g_list_remove (context->source_lists, source_list);
1201 g_slice_free (GSourceList, source_list);
1202 }
1203 }
1204
1205 static guint
g_source_attach_unlocked(GSource * source,GMainContext * context,gboolean do_wakeup)1206 g_source_attach_unlocked (GSource *source,
1207 GMainContext *context,
1208 gboolean do_wakeup)
1209 {
1210 GSList *tmp_list;
1211 guint id;
1212
1213 /* The counter may have wrapped, so we must ensure that we do not
1214 * reuse the source id of an existing source.
1215 */
1216 do
1217 id = context->next_id++;
1218 while (id == 0 || g_hash_table_contains (context->sources, GUINT_TO_POINTER (id)));
1219
1220 source->context = context;
1221 source->source_id = id;
1222 g_source_ref (source);
1223
1224 g_hash_table_insert (context->sources, GUINT_TO_POINTER (id), source);
1225
1226 source_add_to_context (source, context);
1227
1228 if (!SOURCE_BLOCKED (source))
1229 {
1230 tmp_list = source->poll_fds;
1231 while (tmp_list)
1232 {
1233 g_main_context_add_poll_unlocked (context, source->priority, tmp_list->data);
1234 tmp_list = tmp_list->next;
1235 }
1236
1237 for (tmp_list = source->priv->fds; tmp_list; tmp_list = tmp_list->next)
1238 g_main_context_add_poll_unlocked (context, source->priority, tmp_list->data);
1239 }
1240
1241 tmp_list = source->priv->child_sources;
1242 while (tmp_list)
1243 {
1244 g_source_attach_unlocked (tmp_list->data, context, FALSE);
1245 tmp_list = tmp_list->next;
1246 }
1247
1248 /* If another thread has acquired the context, wake it up since it
1249 * might be in poll() right now.
1250 */
1251 if (do_wakeup && context->owner && context->owner != G_THREAD_SELF)
1252 g_wakeup_signal (context->wakeup);
1253
1254 g_trace_mark (G_TRACE_CURRENT_TIME, 0,
1255 "GLib", "g_source_attach",
1256 "%s to context %p",
1257 (g_source_get_name (source) != NULL) ? g_source_get_name (source) : "(unnamed)",
1258 context);
1259
1260 return source->source_id;
1261 }
1262
1263 /**
1264 * g_source_attach:
1265 * @source: a #GSource
1266 * @context: (nullable): a #GMainContext (if %NULL, the default context will be used)
1267 *
1268 * Adds a #GSource to a @context so that it will be executed within
1269 * that context. Remove it by calling g_source_destroy().
1270 *
1271 * This function is safe to call from any thread, regardless of which thread
1272 * the @context is running in.
1273 *
1274 * Returns: the ID (greater than 0) for the source within the
1275 * #GMainContext.
1276 **/
1277 guint
g_source_attach(GSource * source,GMainContext * context)1278 g_source_attach (GSource *source,
1279 GMainContext *context)
1280 {
1281 guint result = 0;
1282
1283 g_return_val_if_fail (source != NULL, 0);
1284 g_return_val_if_fail (g_atomic_int_get (&source->ref_count) > 0, 0);
1285 g_return_val_if_fail (source->context == NULL, 0);
1286 g_return_val_if_fail (!SOURCE_DESTROYED (source), 0);
1287
1288 if (!context)
1289 context = g_main_context_default ();
1290
1291 LOCK_CONTEXT (context);
1292
1293 result = g_source_attach_unlocked (source, context, TRUE);
1294
1295 TRACE (GLIB_MAIN_SOURCE_ATTACH (g_source_get_name (source), source, context,
1296 result));
1297
1298 UNLOCK_CONTEXT (context);
1299
1300 return result;
1301 }
1302
1303 static void
g_source_destroy_internal(GSource * source,GMainContext * context,gboolean have_lock)1304 g_source_destroy_internal (GSource *source,
1305 GMainContext *context,
1306 gboolean have_lock)
1307 {
1308 TRACE (GLIB_MAIN_SOURCE_DESTROY (g_source_get_name (source), source,
1309 context));
1310
1311 if (!have_lock)
1312 LOCK_CONTEXT (context);
1313
1314 if (!SOURCE_DESTROYED (source))
1315 {
1316 GSList *tmp_list;
1317 gpointer old_cb_data;
1318 GSourceCallbackFuncs *old_cb_funcs;
1319
1320 source->flags &= ~G_HOOK_FLAG_ACTIVE;
1321
1322 old_cb_data = source->callback_data;
1323 old_cb_funcs = source->callback_funcs;
1324
1325 source->callback_data = NULL;
1326 source->callback_funcs = NULL;
1327
1328 if (old_cb_funcs)
1329 {
1330 UNLOCK_CONTEXT (context);
1331 old_cb_funcs->unref (old_cb_data);
1332 LOCK_CONTEXT (context);
1333 }
1334
1335 if (!SOURCE_BLOCKED (source))
1336 {
1337 tmp_list = source->poll_fds;
1338 while (tmp_list)
1339 {
1340 g_main_context_remove_poll_unlocked (context, tmp_list->data);
1341 tmp_list = tmp_list->next;
1342 }
1343
1344 for (tmp_list = source->priv->fds; tmp_list; tmp_list = tmp_list->next)
1345 g_main_context_remove_poll_unlocked (context, tmp_list->data);
1346 }
1347
1348 while (source->priv->child_sources)
1349 g_child_source_remove_internal (source->priv->child_sources->data, context);
1350
1351 if (source->priv->parent_source)
1352 g_child_source_remove_internal (source, context);
1353
1354 g_source_unref_internal (source, context, TRUE);
1355 }
1356
1357 if (!have_lock)
1358 UNLOCK_CONTEXT (context);
1359 }
1360
1361 /**
1362 * g_source_destroy:
1363 * @source: a #GSource
1364 *
1365 * Removes a source from its #GMainContext, if any, and mark it as
1366 * destroyed. The source cannot be subsequently added to another
1367 * context. It is safe to call this on sources which have already been
1368 * removed from their context.
1369 *
1370 * This does not unref the #GSource: if you still hold a reference, use
1371 * g_source_unref() to drop it.
1372 *
1373 * This function is safe to call from any thread, regardless of which thread
1374 * the #GMainContext is running in.
1375 *
1376 * If the source is currently attached to a #GMainContext, destroying it
1377 * will effectively unset the callback similar to calling g_source_set_callback().
1378 * This can mean, that the data's #GDestroyNotify gets called right away.
1379 */
1380 void
g_source_destroy(GSource * source)1381 g_source_destroy (GSource *source)
1382 {
1383 GMainContext *context;
1384
1385 g_return_if_fail (source != NULL);
1386 g_return_if_fail (g_atomic_int_get (&source->ref_count) > 0);
1387
1388 context = source->context;
1389
1390 if (context)
1391 g_source_destroy_internal (source, context, FALSE);
1392 else
1393 source->flags &= ~G_HOOK_FLAG_ACTIVE;
1394 }
1395
1396 /**
1397 * g_source_get_id:
1398 * @source: a #GSource
1399 *
1400 * Returns the numeric ID for a particular source. The ID of a source
1401 * is a positive integer which is unique within a particular main loop
1402 * context. The reverse
1403 * mapping from ID to source is done by g_main_context_find_source_by_id().
1404 *
1405 * You can only call this function while the source is associated to a
1406 * #GMainContext instance; calling this function before g_source_attach()
1407 * or after g_source_destroy() yields undefined behavior. The ID returned
1408 * is unique within the #GMainContext instance passed to g_source_attach().
1409 *
1410 * Returns: the ID (greater than 0) for the source
1411 **/
1412 guint
g_source_get_id(GSource * source)1413 g_source_get_id (GSource *source)
1414 {
1415 guint result;
1416
1417 g_return_val_if_fail (source != NULL, 0);
1418 g_return_val_if_fail (g_atomic_int_get (&source->ref_count) > 0, 0);
1419 g_return_val_if_fail (source->context != NULL, 0);
1420
1421 LOCK_CONTEXT (source->context);
1422 result = source->source_id;
1423 UNLOCK_CONTEXT (source->context);
1424
1425 return result;
1426 }
1427
1428 /**
1429 * g_source_get_context:
1430 * @source: a #GSource
1431 *
1432 * Gets the #GMainContext with which the source is associated.
1433 *
1434 * You can call this on a source that has been destroyed, provided
1435 * that the #GMainContext it was attached to still exists (in which
1436 * case it will return that #GMainContext). In particular, you can
1437 * always call this function on the source returned from
1438 * g_main_current_source(). But calling this function on a source
1439 * whose #GMainContext has been destroyed is an error.
1440 *
1441 * Returns: (transfer none) (nullable): the #GMainContext with which the
1442 * source is associated, or %NULL if the context has not
1443 * yet been added to a source.
1444 **/
1445 GMainContext *
g_source_get_context(GSource * source)1446 g_source_get_context (GSource *source)
1447 {
1448 g_return_val_if_fail (source != NULL, NULL);
1449 g_return_val_if_fail (g_atomic_int_get (&source->ref_count) > 0, NULL);
1450 g_return_val_if_fail (source->context != NULL || !SOURCE_DESTROYED (source), NULL);
1451
1452 return source->context;
1453 }
1454
1455 /**
1456 * g_source_add_poll:
1457 * @source:a #GSource
1458 * @fd: a #GPollFD structure holding information about a file
1459 * descriptor to watch.
1460 *
1461 * Adds a file descriptor to the set of file descriptors polled for
1462 * this source. This is usually combined with g_source_new() to add an
1463 * event source. The event source's check function will typically test
1464 * the @revents field in the #GPollFD struct and return %TRUE if events need
1465 * to be processed.
1466 *
1467 * This API is only intended to be used by implementations of #GSource.
1468 * Do not call this API on a #GSource that you did not create.
1469 *
1470 * Using this API forces the linear scanning of event sources on each
1471 * main loop iteration. Newly-written event sources should try to use
1472 * g_source_add_unix_fd() instead of this API.
1473 **/
1474 void
g_source_add_poll(GSource * source,GPollFD * fd)1475 g_source_add_poll (GSource *source,
1476 GPollFD *fd)
1477 {
1478 GMainContext *context;
1479
1480 g_return_if_fail (source != NULL);
1481 g_return_if_fail (g_atomic_int_get (&source->ref_count) > 0);
1482 g_return_if_fail (fd != NULL);
1483 g_return_if_fail (!SOURCE_DESTROYED (source));
1484
1485 context = source->context;
1486
1487 if (context)
1488 LOCK_CONTEXT (context);
1489
1490 source->poll_fds = g_slist_prepend (source->poll_fds, fd);
1491
1492 if (context)
1493 {
1494 if (!SOURCE_BLOCKED (source))
1495 g_main_context_add_poll_unlocked (context, source->priority, fd);
1496 UNLOCK_CONTEXT (context);
1497 }
1498 }
1499
1500 /**
1501 * g_source_remove_poll:
1502 * @source:a #GSource
1503 * @fd: a #GPollFD structure previously passed to g_source_add_poll().
1504 *
1505 * Removes a file descriptor from the set of file descriptors polled for
1506 * this source.
1507 *
1508 * This API is only intended to be used by implementations of #GSource.
1509 * Do not call this API on a #GSource that you did not create.
1510 **/
1511 void
g_source_remove_poll(GSource * source,GPollFD * fd)1512 g_source_remove_poll (GSource *source,
1513 GPollFD *fd)
1514 {
1515 GMainContext *context;
1516
1517 g_return_if_fail (source != NULL);
1518 g_return_if_fail (g_atomic_int_get (&source->ref_count) > 0);
1519 g_return_if_fail (fd != NULL);
1520 g_return_if_fail (!SOURCE_DESTROYED (source));
1521
1522 context = source->context;
1523
1524 if (context)
1525 LOCK_CONTEXT (context);
1526
1527 source->poll_fds = g_slist_remove (source->poll_fds, fd);
1528
1529 if (context)
1530 {
1531 if (!SOURCE_BLOCKED (source))
1532 g_main_context_remove_poll_unlocked (context, fd);
1533 UNLOCK_CONTEXT (context);
1534 }
1535 }
1536
1537 /**
1538 * g_source_add_child_source:
1539 * @source:a #GSource
1540 * @child_source: a second #GSource that @source should "poll"
1541 *
1542 * Adds @child_source to @source as a "polled" source; when @source is
1543 * added to a #GMainContext, @child_source will be automatically added
1544 * with the same priority, when @child_source is triggered, it will
1545 * cause @source to dispatch (in addition to calling its own
1546 * callback), and when @source is destroyed, it will destroy
1547 * @child_source as well. (@source will also still be dispatched if
1548 * its own prepare/check functions indicate that it is ready.)
1549 *
1550 * If you don't need @child_source to do anything on its own when it
1551 * triggers, you can call g_source_set_dummy_callback() on it to set a
1552 * callback that does nothing (except return %TRUE if appropriate).
1553 *
1554 * @source will hold a reference on @child_source while @child_source
1555 * is attached to it.
1556 *
1557 * This API is only intended to be used by implementations of #GSource.
1558 * Do not call this API on a #GSource that you did not create.
1559 *
1560 * Since: 2.28
1561 **/
1562 void
g_source_add_child_source(GSource * source,GSource * child_source)1563 g_source_add_child_source (GSource *source,
1564 GSource *child_source)
1565 {
1566 GMainContext *context;
1567
1568 g_return_if_fail (source != NULL);
1569 g_return_if_fail (g_atomic_int_get (&source->ref_count) > 0);
1570 g_return_if_fail (child_source != NULL);
1571 g_return_if_fail (g_atomic_int_get (&child_source->ref_count) > 0);
1572 g_return_if_fail (!SOURCE_DESTROYED (source));
1573 g_return_if_fail (!SOURCE_DESTROYED (child_source));
1574 g_return_if_fail (child_source->context == NULL);
1575 g_return_if_fail (child_source->priv->parent_source == NULL);
1576
1577 context = source->context;
1578
1579 if (context)
1580 LOCK_CONTEXT (context);
1581
1582 TRACE (GLIB_SOURCE_ADD_CHILD_SOURCE (source, child_source));
1583
1584 source->priv->child_sources = g_slist_prepend (source->priv->child_sources,
1585 g_source_ref (child_source));
1586 child_source->priv->parent_source = source;
1587 g_source_set_priority_unlocked (child_source, NULL, source->priority);
1588 if (SOURCE_BLOCKED (source))
1589 block_source (child_source);
1590
1591 if (context)
1592 {
1593 g_source_attach_unlocked (child_source, context, TRUE);
1594 UNLOCK_CONTEXT (context);
1595 }
1596 }
1597
1598 static void
g_child_source_remove_internal(GSource * child_source,GMainContext * context)1599 g_child_source_remove_internal (GSource *child_source,
1600 GMainContext *context)
1601 {
1602 GSource *parent_source = child_source->priv->parent_source;
1603
1604 parent_source->priv->child_sources =
1605 g_slist_remove (parent_source->priv->child_sources, child_source);
1606 child_source->priv->parent_source = NULL;
1607
1608 g_source_destroy_internal (child_source, context, TRUE);
1609 g_source_unref_internal (child_source, context, TRUE);
1610 }
1611
1612 /**
1613 * g_source_remove_child_source:
1614 * @source:a #GSource
1615 * @child_source: a #GSource previously passed to
1616 * g_source_add_child_source().
1617 *
1618 * Detaches @child_source from @source and destroys it.
1619 *
1620 * This API is only intended to be used by implementations of #GSource.
1621 * Do not call this API on a #GSource that you did not create.
1622 *
1623 * Since: 2.28
1624 **/
1625 void
g_source_remove_child_source(GSource * source,GSource * child_source)1626 g_source_remove_child_source (GSource *source,
1627 GSource *child_source)
1628 {
1629 GMainContext *context;
1630
1631 g_return_if_fail (source != NULL);
1632 g_return_if_fail (g_atomic_int_get (&source->ref_count) > 0);
1633 g_return_if_fail (child_source != NULL);
1634 g_return_if_fail (g_atomic_int_get (&child_source->ref_count) > 0);
1635 g_return_if_fail (child_source->priv->parent_source == source);
1636 g_return_if_fail (!SOURCE_DESTROYED (source));
1637 g_return_if_fail (!SOURCE_DESTROYED (child_source));
1638
1639 context = source->context;
1640
1641 if (context)
1642 LOCK_CONTEXT (context);
1643
1644 g_child_source_remove_internal (child_source, context);
1645
1646 if (context)
1647 UNLOCK_CONTEXT (context);
1648 }
1649
1650 static void
g_source_callback_ref(gpointer cb_data)1651 g_source_callback_ref (gpointer cb_data)
1652 {
1653 GSourceCallback *callback = cb_data;
1654
1655 g_atomic_int_inc (&callback->ref_count);
1656 }
1657
1658 static void
g_source_callback_unref(gpointer cb_data)1659 g_source_callback_unref (gpointer cb_data)
1660 {
1661 GSourceCallback *callback = cb_data;
1662
1663 if (g_atomic_int_dec_and_test (&callback->ref_count))
1664 {
1665 if (callback->notify)
1666 callback->notify (callback->data);
1667 g_free (callback);
1668 }
1669 }
1670
1671 static void
g_source_callback_get(gpointer cb_data,GSource * source,GSourceFunc * func,gpointer * data)1672 g_source_callback_get (gpointer cb_data,
1673 GSource *source,
1674 GSourceFunc *func,
1675 gpointer *data)
1676 {
1677 GSourceCallback *callback = cb_data;
1678
1679 *func = callback->func;
1680 *data = callback->data;
1681 }
1682
1683 static GSourceCallbackFuncs g_source_callback_funcs = {
1684 g_source_callback_ref,
1685 g_source_callback_unref,
1686 g_source_callback_get,
1687 };
1688
1689 /**
1690 * g_source_set_callback_indirect:
1691 * @source: the source
1692 * @callback_data: pointer to callback data "object"
1693 * @callback_funcs: functions for reference counting @callback_data
1694 * and getting the callback and data
1695 *
1696 * Sets the callback function storing the data as a refcounted callback
1697 * "object". This is used internally. Note that calling
1698 * g_source_set_callback_indirect() assumes
1699 * an initial reference count on @callback_data, and thus
1700 * @callback_funcs->unref will eventually be called once more
1701 * than @callback_funcs->ref.
1702 *
1703 * It is safe to call this function multiple times on a source which has already
1704 * been attached to a context. The changes will take effect for the next time
1705 * the source is dispatched after this call returns.
1706 **/
1707 void
g_source_set_callback_indirect(GSource * source,gpointer callback_data,GSourceCallbackFuncs * callback_funcs)1708 g_source_set_callback_indirect (GSource *source,
1709 gpointer callback_data,
1710 GSourceCallbackFuncs *callback_funcs)
1711 {
1712 GMainContext *context;
1713 gpointer old_cb_data;
1714 GSourceCallbackFuncs *old_cb_funcs;
1715
1716 g_return_if_fail (source != NULL);
1717 g_return_if_fail (g_atomic_int_get (&source->ref_count) > 0);
1718 g_return_if_fail (callback_funcs != NULL || callback_data == NULL);
1719
1720 context = source->context;
1721
1722 if (context)
1723 LOCK_CONTEXT (context);
1724
1725 if (callback_funcs != &g_source_callback_funcs)
1726 {
1727 TRACE (GLIB_SOURCE_SET_CALLBACK_INDIRECT (source, callback_data,
1728 callback_funcs->ref,
1729 callback_funcs->unref,
1730 callback_funcs->get));
1731 }
1732
1733 old_cb_data = source->callback_data;
1734 old_cb_funcs = source->callback_funcs;
1735
1736 source->callback_data = callback_data;
1737 source->callback_funcs = callback_funcs;
1738
1739 if (context)
1740 UNLOCK_CONTEXT (context);
1741
1742 if (old_cb_funcs)
1743 old_cb_funcs->unref (old_cb_data);
1744 }
1745
1746 /**
1747 * g_source_set_callback:
1748 * @source: the source
1749 * @func: a callback function
1750 * @data: the data to pass to callback function
1751 * @notify: (nullable): a function to call when @data is no longer in use, or %NULL.
1752 *
1753 * Sets the callback function for a source. The callback for a source is
1754 * called from the source's dispatch function.
1755 *
1756 * The exact type of @func depends on the type of source; ie. you
1757 * should not count on @func being called with @data as its first
1758 * parameter. Cast @func with G_SOURCE_FUNC() to avoid warnings about
1759 * incompatible function types.
1760 *
1761 * See [memory management of sources][mainloop-memory-management] for details
1762 * on how to handle memory management of @data.
1763 *
1764 * Typically, you won't use this function. Instead use functions specific
1765 * to the type of source you are using, such as g_idle_add() or g_timeout_add().
1766 *
1767 * It is safe to call this function multiple times on a source which has already
1768 * been attached to a context. The changes will take effect for the next time
1769 * the source is dispatched after this call returns.
1770 *
1771 * Note that g_source_destroy() for a currently attached source has the effect
1772 * of also unsetting the callback.
1773 **/
1774 void
g_source_set_callback(GSource * source,GSourceFunc func,gpointer data,GDestroyNotify notify)1775 g_source_set_callback (GSource *source,
1776 GSourceFunc func,
1777 gpointer data,
1778 GDestroyNotify notify)
1779 {
1780 GSourceCallback *new_callback;
1781
1782 g_return_if_fail (source != NULL);
1783 g_return_if_fail (g_atomic_int_get (&source->ref_count) > 0);
1784
1785 TRACE (GLIB_SOURCE_SET_CALLBACK (source, func, data, notify));
1786
1787 new_callback = g_new (GSourceCallback, 1);
1788
1789 new_callback->ref_count = 1;
1790 new_callback->func = func;
1791 new_callback->data = data;
1792 new_callback->notify = notify;
1793
1794 g_source_set_callback_indirect (source, new_callback, &g_source_callback_funcs);
1795 }
1796
1797
1798 /**
1799 * g_source_set_funcs:
1800 * @source: a #GSource
1801 * @funcs: the new #GSourceFuncs
1802 *
1803 * Sets the source functions (can be used to override
1804 * default implementations) of an unattached source.
1805 *
1806 * Since: 2.12
1807 */
1808 void
g_source_set_funcs(GSource * source,GSourceFuncs * funcs)1809 g_source_set_funcs (GSource *source,
1810 GSourceFuncs *funcs)
1811 {
1812 g_return_if_fail (source != NULL);
1813 g_return_if_fail (source->context == NULL);
1814 g_return_if_fail (g_atomic_int_get (&source->ref_count) > 0);
1815 g_return_if_fail (funcs != NULL);
1816
1817 source->source_funcs = funcs;
1818 }
1819
1820 static void
g_source_set_priority_unlocked(GSource * source,GMainContext * context,gint priority)1821 g_source_set_priority_unlocked (GSource *source,
1822 GMainContext *context,
1823 gint priority)
1824 {
1825 GSList *tmp_list;
1826
1827 g_return_if_fail (source->priv->parent_source == NULL ||
1828 source->priv->parent_source->priority == priority);
1829
1830 TRACE (GLIB_SOURCE_SET_PRIORITY (source, context, priority));
1831
1832 if (context)
1833 {
1834 /* Remove the source from the context's source and then
1835 * add it back after so it is sorted in the correct place
1836 */
1837 source_remove_from_context (source, source->context);
1838 }
1839
1840 source->priority = priority;
1841
1842 if (context)
1843 {
1844 source_add_to_context (source, source->context);
1845
1846 if (!SOURCE_BLOCKED (source))
1847 {
1848 tmp_list = source->poll_fds;
1849 while (tmp_list)
1850 {
1851 g_main_context_remove_poll_unlocked (context, tmp_list->data);
1852 g_main_context_add_poll_unlocked (context, priority, tmp_list->data);
1853
1854 tmp_list = tmp_list->next;
1855 }
1856
1857 for (tmp_list = source->priv->fds; tmp_list; tmp_list = tmp_list->next)
1858 {
1859 g_main_context_remove_poll_unlocked (context, tmp_list->data);
1860 g_main_context_add_poll_unlocked (context, priority, tmp_list->data);
1861 }
1862 }
1863 }
1864
1865 if (source->priv->child_sources)
1866 {
1867 tmp_list = source->priv->child_sources;
1868 while (tmp_list)
1869 {
1870 g_source_set_priority_unlocked (tmp_list->data, context, priority);
1871 tmp_list = tmp_list->next;
1872 }
1873 }
1874 }
1875
1876 /**
1877 * g_source_set_priority:
1878 * @source: a #GSource
1879 * @priority: the new priority.
1880 *
1881 * Sets the priority of a source. While the main loop is being run, a
1882 * source will be dispatched if it is ready to be dispatched and no
1883 * sources at a higher (numerically smaller) priority are ready to be
1884 * dispatched.
1885 *
1886 * A child source always has the same priority as its parent. It is not
1887 * permitted to change the priority of a source once it has been added
1888 * as a child of another source.
1889 **/
1890 void
g_source_set_priority(GSource * source,gint priority)1891 g_source_set_priority (GSource *source,
1892 gint priority)
1893 {
1894 GMainContext *context;
1895
1896 g_return_if_fail (source != NULL);
1897 g_return_if_fail (g_atomic_int_get (&source->ref_count) > 0);
1898 g_return_if_fail (source->priv->parent_source == NULL);
1899
1900 context = source->context;
1901
1902 if (context)
1903 LOCK_CONTEXT (context);
1904 g_source_set_priority_unlocked (source, context, priority);
1905 if (context)
1906 UNLOCK_CONTEXT (context);
1907 }
1908
1909 /**
1910 * g_source_get_priority:
1911 * @source: a #GSource
1912 *
1913 * Gets the priority of a source.
1914 *
1915 * Returns: the priority of the source
1916 **/
1917 gint
g_source_get_priority(GSource * source)1918 g_source_get_priority (GSource *source)
1919 {
1920 g_return_val_if_fail (source != NULL, 0);
1921 g_return_val_if_fail (g_atomic_int_get (&source->ref_count) > 0, 0);
1922
1923 return source->priority;
1924 }
1925
1926 /**
1927 * g_source_set_ready_time:
1928 * @source: a #GSource
1929 * @ready_time: the monotonic time at which the source will be ready,
1930 * 0 for "immediately", -1 for "never"
1931 *
1932 * Sets a #GSource to be dispatched when the given monotonic time is
1933 * reached (or passed). If the monotonic time is in the past (as it
1934 * always will be if @ready_time is 0) then the source will be
1935 * dispatched immediately.
1936 *
1937 * If @ready_time is -1 then the source is never woken up on the basis
1938 * of the passage of time.
1939 *
1940 * Dispatching the source does not reset the ready time. You should do
1941 * so yourself, from the source dispatch function.
1942 *
1943 * Note that if you have a pair of sources where the ready time of one
1944 * suggests that it will be delivered first but the priority for the
1945 * other suggests that it would be delivered first, and the ready time
1946 * for both sources is reached during the same main context iteration,
1947 * then the order of dispatch is undefined.
1948 *
1949 * It is a no-op to call this function on a #GSource which has already been
1950 * destroyed with g_source_destroy().
1951 *
1952 * This API is only intended to be used by implementations of #GSource.
1953 * Do not call this API on a #GSource that you did not create.
1954 *
1955 * Since: 2.36
1956 **/
1957 void
g_source_set_ready_time(GSource * source,gint64 ready_time)1958 g_source_set_ready_time (GSource *source,
1959 gint64 ready_time)
1960 {
1961 GMainContext *context;
1962
1963 g_return_if_fail (source != NULL);
1964 g_return_if_fail (g_atomic_int_get (&source->ref_count) > 0);
1965
1966 context = source->context;
1967
1968 if (context)
1969 LOCK_CONTEXT (context);
1970
1971 if (source->priv->ready_time == ready_time)
1972 {
1973 if (context)
1974 UNLOCK_CONTEXT (context);
1975
1976 return;
1977 }
1978
1979 source->priv->ready_time = ready_time;
1980
1981 TRACE (GLIB_SOURCE_SET_READY_TIME (source, ready_time));
1982
1983 if (context)
1984 {
1985 /* Quite likely that we need to change the timeout on the poll */
1986 if (!SOURCE_BLOCKED (source))
1987 g_wakeup_signal (context->wakeup);
1988 UNLOCK_CONTEXT (context);
1989 }
1990 }
1991
1992 /**
1993 * g_source_get_ready_time:
1994 * @source: a #GSource
1995 *
1996 * Gets the "ready time" of @source, as set by
1997 * g_source_set_ready_time().
1998 *
1999 * Any time before the current monotonic time (including 0) is an
2000 * indication that the source will fire immediately.
2001 *
2002 * Returns: the monotonic ready time, -1 for "never"
2003 **/
2004 gint64
g_source_get_ready_time(GSource * source)2005 g_source_get_ready_time (GSource *source)
2006 {
2007 g_return_val_if_fail (source != NULL, -1);
2008 g_return_val_if_fail (g_atomic_int_get (&source->ref_count) > 0, -1);
2009
2010 return source->priv->ready_time;
2011 }
2012
2013 /**
2014 * g_source_set_can_recurse:
2015 * @source: a #GSource
2016 * @can_recurse: whether recursion is allowed for this source
2017 *
2018 * Sets whether a source can be called recursively. If @can_recurse is
2019 * %TRUE, then while the source is being dispatched then this source
2020 * will be processed normally. Otherwise, all processing of this
2021 * source is blocked until the dispatch function returns.
2022 **/
2023 void
g_source_set_can_recurse(GSource * source,gboolean can_recurse)2024 g_source_set_can_recurse (GSource *source,
2025 gboolean can_recurse)
2026 {
2027 GMainContext *context;
2028
2029 g_return_if_fail (source != NULL);
2030 g_return_if_fail (g_atomic_int_get (&source->ref_count) > 0);
2031
2032 context = source->context;
2033
2034 if (context)
2035 LOCK_CONTEXT (context);
2036
2037 if (can_recurse)
2038 source->flags |= G_SOURCE_CAN_RECURSE;
2039 else
2040 source->flags &= ~G_SOURCE_CAN_RECURSE;
2041
2042 if (context)
2043 UNLOCK_CONTEXT (context);
2044 }
2045
2046 /**
2047 * g_source_get_can_recurse:
2048 * @source: a #GSource
2049 *
2050 * Checks whether a source is allowed to be called recursively.
2051 * see g_source_set_can_recurse().
2052 *
2053 * Returns: whether recursion is allowed.
2054 **/
2055 gboolean
g_source_get_can_recurse(GSource * source)2056 g_source_get_can_recurse (GSource *source)
2057 {
2058 g_return_val_if_fail (source != NULL, FALSE);
2059 g_return_val_if_fail (g_atomic_int_get (&source->ref_count) > 0, FALSE);
2060
2061 return (source->flags & G_SOURCE_CAN_RECURSE) != 0;
2062 }
2063
2064 static void
g_source_set_name_full(GSource * source,const char * name,gboolean is_static)2065 g_source_set_name_full (GSource *source,
2066 const char *name,
2067 gboolean is_static)
2068 {
2069 GMainContext *context;
2070
2071 g_return_if_fail (source != NULL);
2072 g_return_if_fail (g_atomic_int_get (&source->ref_count) > 0);
2073
2074 context = source->context;
2075
2076 if (context)
2077 LOCK_CONTEXT (context);
2078
2079 TRACE (GLIB_SOURCE_SET_NAME (source, name));
2080
2081 /* setting back to NULL is allowed, just because it's
2082 * weird if get_name can return NULL but you can't
2083 * set that.
2084 */
2085
2086 if (!source->priv->static_name)
2087 g_free (source->name);
2088
2089 if (is_static)
2090 source->name = (char *)name;
2091 else
2092 source->name = g_strdup (name);
2093
2094 source->priv->static_name = is_static;
2095
2096 if (context)
2097 UNLOCK_CONTEXT (context);
2098 }
2099
2100 /**
2101 * g_source_set_name:
2102 * @source: a #GSource
2103 * @name: debug name for the source
2104 *
2105 * Sets a name for the source, used in debugging and profiling.
2106 * The name defaults to #NULL.
2107 *
2108 * The source name should describe in a human-readable way
2109 * what the source does. For example, "X11 event queue"
2110 * or "GTK+ repaint idle handler" or whatever it is.
2111 *
2112 * It is permitted to call this function multiple times, but is not
2113 * recommended due to the potential performance impact. For example,
2114 * one could change the name in the "check" function of a #GSourceFuncs
2115 * to include details like the event type in the source name.
2116 *
2117 * Use caution if changing the name while another thread may be
2118 * accessing it with g_source_get_name(); that function does not copy
2119 * the value, and changing the value will free it while the other thread
2120 * may be attempting to use it.
2121 *
2122 * Also see g_source_set_static_name().
2123 *
2124 * Since: 2.26
2125 **/
2126 void
g_source_set_name(GSource * source,const char * name)2127 g_source_set_name (GSource *source,
2128 const char *name)
2129 {
2130 g_source_set_name_full (source, name, FALSE);
2131 }
2132
2133 /**
2134 * g_source_set_static_name:
2135 * @source: a #GSource
2136 * @name: debug name for the source
2137 *
2138 * A variant of g_source_set_name() that does not
2139 * duplicate the @name, and can only be used with
2140 * string literals.
2141 *
2142 * Since: 2.70
2143 */
2144 void
g_source_set_static_name(GSource * source,const char * name)2145 g_source_set_static_name (GSource *source,
2146 const char *name)
2147 {
2148 g_source_set_name_full (source, name, TRUE);
2149 }
2150
2151 /**
2152 * g_source_get_name:
2153 * @source: a #GSource
2154 *
2155 * Gets a name for the source, used in debugging and profiling. The
2156 * name may be #NULL if it has never been set with g_source_set_name().
2157 *
2158 * Returns: (nullable): the name of the source
2159 *
2160 * Since: 2.26
2161 **/
2162 const char *
g_source_get_name(GSource * source)2163 g_source_get_name (GSource *source)
2164 {
2165 g_return_val_if_fail (source != NULL, NULL);
2166 g_return_val_if_fail (g_atomic_int_get (&source->ref_count) > 0, NULL);
2167
2168 return source->name;
2169 }
2170
2171 /**
2172 * g_source_set_name_by_id:
2173 * @tag: a #GSource ID
2174 * @name: debug name for the source
2175 *
2176 * Sets the name of a source using its ID.
2177 *
2178 * This is a convenience utility to set source names from the return
2179 * value of g_idle_add(), g_timeout_add(), etc.
2180 *
2181 * It is a programmer error to attempt to set the name of a non-existent
2182 * source.
2183 *
2184 * More specifically: source IDs can be reissued after a source has been
2185 * destroyed and therefore it is never valid to use this function with a
2186 * source ID which may have already been removed. An example is when
2187 * scheduling an idle to run in another thread with g_idle_add(): the
2188 * idle may already have run and been removed by the time this function
2189 * is called on its (now invalid) source ID. This source ID may have
2190 * been reissued, leading to the operation being performed against the
2191 * wrong source.
2192 *
2193 * Since: 2.26
2194 **/
2195 void
g_source_set_name_by_id(guint tag,const char * name)2196 g_source_set_name_by_id (guint tag,
2197 const char *name)
2198 {
2199 GSource *source;
2200
2201 g_return_if_fail (tag > 0);
2202
2203 source = g_main_context_find_source_by_id (NULL, tag);
2204 if (source == NULL)
2205 return;
2206
2207 g_source_set_name (source, name);
2208 }
2209
2210
2211 /**
2212 * g_source_ref:
2213 * @source: a #GSource
2214 *
2215 * Increases the reference count on a source by one.
2216 *
2217 * Returns: @source
2218 **/
2219 GSource *
g_source_ref(GSource * source)2220 g_source_ref (GSource *source)
2221 {
2222 g_return_val_if_fail (source != NULL, NULL);
2223 /* We allow ref_count == 0 here to allow the dispose function to resurrect
2224 * the GSource if needed */
2225 g_return_val_if_fail (g_atomic_int_get (&source->ref_count) >= 0, NULL);
2226
2227 g_atomic_int_inc (&source->ref_count);
2228
2229 return source;
2230 }
2231
2232 /* g_source_unref() but possible to call within context lock
2233 */
2234 static void
g_source_unref_internal(GSource * source,GMainContext * context,gboolean have_lock)2235 g_source_unref_internal (GSource *source,
2236 GMainContext *context,
2237 gboolean have_lock)
2238 {
2239 gpointer old_cb_data = NULL;
2240 GSourceCallbackFuncs *old_cb_funcs = NULL;
2241
2242 g_return_if_fail (source != NULL);
2243
2244 if (!have_lock && context)
2245 LOCK_CONTEXT (context);
2246
2247 if (g_atomic_int_dec_and_test (&source->ref_count))
2248 {
2249 /* If there's a dispose function, call this first */
2250 if (source->priv->dispose)
2251 {
2252 /* Temporarily increase the ref count again so that GSource methods
2253 * can be called from dispose(). */
2254 g_atomic_int_inc (&source->ref_count);
2255 if (context)
2256 UNLOCK_CONTEXT (context);
2257 source->priv->dispose (source);
2258 if (context)
2259 LOCK_CONTEXT (context);
2260
2261 /* Now the reference count might be bigger than 0 again, in which
2262 * case we simply return from here before freeing the source */
2263 if (!g_atomic_int_dec_and_test (&source->ref_count))
2264 {
2265 if (!have_lock && context)
2266 UNLOCK_CONTEXT (context);
2267 return;
2268 }
2269 }
2270
2271 TRACE (GLIB_SOURCE_BEFORE_FREE (source, context,
2272 source->source_funcs->finalize));
2273
2274 old_cb_data = source->callback_data;
2275 old_cb_funcs = source->callback_funcs;
2276
2277 source->callback_data = NULL;
2278 source->callback_funcs = NULL;
2279
2280 if (context)
2281 {
2282 if (!SOURCE_DESTROYED (source))
2283 g_warning (G_STRLOC ": ref_count == 0, but source was still attached to a context!");
2284 source_remove_from_context (source, context);
2285
2286 g_hash_table_remove (context->sources, GUINT_TO_POINTER (source->source_id));
2287 }
2288
2289 if (source->source_funcs->finalize)
2290 {
2291 gint old_ref_count;
2292
2293 /* Temporarily increase the ref count again so that GSource methods
2294 * can be called from finalize(). */
2295 g_atomic_int_inc (&source->ref_count);
2296 if (context)
2297 UNLOCK_CONTEXT (context);
2298 source->source_funcs->finalize (source);
2299 if (context)
2300 LOCK_CONTEXT (context);
2301 old_ref_count = g_atomic_int_add (&source->ref_count, -1);
2302 g_warn_if_fail (old_ref_count == 1);
2303 }
2304
2305 if (old_cb_funcs)
2306 {
2307 gint old_ref_count;
2308
2309 /* Temporarily increase the ref count again so that GSource methods
2310 * can be called from callback_funcs.unref(). */
2311 g_atomic_int_inc (&source->ref_count);
2312 if (context)
2313 UNLOCK_CONTEXT (context);
2314
2315 old_cb_funcs->unref (old_cb_data);
2316
2317 if (context)
2318 LOCK_CONTEXT (context);
2319 old_ref_count = g_atomic_int_add (&source->ref_count, -1);
2320 g_warn_if_fail (old_ref_count == 1);
2321 }
2322
2323 if (!source->priv->static_name)
2324 g_free (source->name);
2325 source->name = NULL;
2326
2327 g_slist_free (source->poll_fds);
2328 source->poll_fds = NULL;
2329
2330 g_slist_free_full (source->priv->fds, g_free);
2331
2332 while (source->priv->child_sources)
2333 {
2334 GSource *child_source = source->priv->child_sources->data;
2335
2336 source->priv->child_sources =
2337 g_slist_remove (source->priv->child_sources, child_source);
2338 child_source->priv->parent_source = NULL;
2339
2340 g_source_unref_internal (child_source, context, TRUE);
2341 }
2342
2343 g_slice_free (GSourcePrivate, source->priv);
2344 source->priv = NULL;
2345
2346 g_free (source);
2347 }
2348
2349 if (!have_lock && context)
2350 UNLOCK_CONTEXT (context);
2351 }
2352
2353 /**
2354 * g_source_unref:
2355 * @source: a #GSource
2356 *
2357 * Decreases the reference count of a source by one. If the
2358 * resulting reference count is zero the source and associated
2359 * memory will be destroyed.
2360 **/
2361 void
g_source_unref(GSource * source)2362 g_source_unref (GSource *source)
2363 {
2364 g_return_if_fail (source != NULL);
2365 g_return_if_fail (g_atomic_int_get (&source->ref_count) > 0);
2366
2367 g_source_unref_internal (source, source->context, FALSE);
2368 }
2369
2370 /**
2371 * g_main_context_find_source_by_id:
2372 * @context: (nullable): a #GMainContext (if %NULL, the default context will be used)
2373 * @source_id: the source ID, as returned by g_source_get_id().
2374 *
2375 * Finds a #GSource given a pair of context and ID.
2376 *
2377 * It is a programmer error to attempt to look up a non-existent source.
2378 *
2379 * More specifically: source IDs can be reissued after a source has been
2380 * destroyed and therefore it is never valid to use this function with a
2381 * source ID which may have already been removed. An example is when
2382 * scheduling an idle to run in another thread with g_idle_add(): the
2383 * idle may already have run and been removed by the time this function
2384 * is called on its (now invalid) source ID. This source ID may have
2385 * been reissued, leading to the operation being performed against the
2386 * wrong source.
2387 *
2388 * Returns: (transfer none): the #GSource
2389 **/
2390 GSource *
g_main_context_find_source_by_id(GMainContext * context,guint source_id)2391 g_main_context_find_source_by_id (GMainContext *context,
2392 guint source_id)
2393 {
2394 GSource *source;
2395
2396 g_return_val_if_fail (source_id > 0, NULL);
2397
2398 if (context == NULL)
2399 context = g_main_context_default ();
2400
2401 LOCK_CONTEXT (context);
2402 source = g_hash_table_lookup (context->sources, GUINT_TO_POINTER (source_id));
2403 UNLOCK_CONTEXT (context);
2404
2405 if (source && SOURCE_DESTROYED (source))
2406 source = NULL;
2407
2408 return source;
2409 }
2410
2411 /**
2412 * g_main_context_find_source_by_funcs_user_data:
2413 * @context: (nullable): a #GMainContext (if %NULL, the default context will be used).
2414 * @funcs: the @source_funcs passed to g_source_new().
2415 * @user_data: the user data from the callback.
2416 *
2417 * Finds a source with the given source functions and user data. If
2418 * multiple sources exist with the same source function and user data,
2419 * the first one found will be returned.
2420 *
2421 * Returns: (transfer none): the source, if one was found, otherwise %NULL
2422 **/
2423 GSource *
g_main_context_find_source_by_funcs_user_data(GMainContext * context,GSourceFuncs * funcs,gpointer user_data)2424 g_main_context_find_source_by_funcs_user_data (GMainContext *context,
2425 GSourceFuncs *funcs,
2426 gpointer user_data)
2427 {
2428 GSourceIter iter;
2429 GSource *source;
2430
2431 g_return_val_if_fail (funcs != NULL, NULL);
2432
2433 if (context == NULL)
2434 context = g_main_context_default ();
2435
2436 LOCK_CONTEXT (context);
2437
2438 g_source_iter_init (&iter, context, FALSE);
2439 while (g_source_iter_next (&iter, &source))
2440 {
2441 if (!SOURCE_DESTROYED (source) &&
2442 source->source_funcs == funcs &&
2443 source->callback_funcs)
2444 {
2445 GSourceFunc callback;
2446 gpointer callback_data;
2447
2448 source->callback_funcs->get (source->callback_data, source, &callback, &callback_data);
2449
2450 if (callback_data == user_data)
2451 break;
2452 }
2453 }
2454 g_source_iter_clear (&iter);
2455
2456 UNLOCK_CONTEXT (context);
2457
2458 return source;
2459 }
2460
2461 /**
2462 * g_main_context_find_source_by_user_data:
2463 * @context: a #GMainContext
2464 * @user_data: the user_data for the callback.
2465 *
2466 * Finds a source with the given user data for the callback. If
2467 * multiple sources exist with the same user data, the first
2468 * one found will be returned.
2469 *
2470 * Returns: (transfer none): the source, if one was found, otherwise %NULL
2471 **/
2472 GSource *
g_main_context_find_source_by_user_data(GMainContext * context,gpointer user_data)2473 g_main_context_find_source_by_user_data (GMainContext *context,
2474 gpointer user_data)
2475 {
2476 GSourceIter iter;
2477 GSource *source;
2478
2479 if (context == NULL)
2480 context = g_main_context_default ();
2481
2482 LOCK_CONTEXT (context);
2483
2484 g_source_iter_init (&iter, context, FALSE);
2485 while (g_source_iter_next (&iter, &source))
2486 {
2487 if (!SOURCE_DESTROYED (source) &&
2488 source->callback_funcs)
2489 {
2490 GSourceFunc callback;
2491 gpointer callback_data = NULL;
2492
2493 source->callback_funcs->get (source->callback_data, source, &callback, &callback_data);
2494
2495 if (callback_data == user_data)
2496 break;
2497 }
2498 }
2499 g_source_iter_clear (&iter);
2500
2501 UNLOCK_CONTEXT (context);
2502
2503 return source;
2504 }
2505
2506 /**
2507 * g_source_remove:
2508 * @tag: the ID of the source to remove.
2509 *
2510 * Removes the source with the given ID from the default main context. You must
2511 * use g_source_destroy() for sources added to a non-default main context.
2512 *
2513 * The ID of a #GSource is given by g_source_get_id(), or will be
2514 * returned by the functions g_source_attach(), g_idle_add(),
2515 * g_idle_add_full(), g_timeout_add(), g_timeout_add_full(),
2516 * g_child_watch_add(), g_child_watch_add_full(), g_io_add_watch(), and
2517 * g_io_add_watch_full().
2518 *
2519 * It is a programmer error to attempt to remove a non-existent source.
2520 *
2521 * More specifically: source IDs can be reissued after a source has been
2522 * destroyed and therefore it is never valid to use this function with a
2523 * source ID which may have already been removed. An example is when
2524 * scheduling an idle to run in another thread with g_idle_add(): the
2525 * idle may already have run and been removed by the time this function
2526 * is called on its (now invalid) source ID. This source ID may have
2527 * been reissued, leading to the operation being performed against the
2528 * wrong source.
2529 *
2530 * Returns: For historical reasons, this function always returns %TRUE
2531 **/
2532 gboolean
g_source_remove(guint tag)2533 g_source_remove (guint tag)
2534 {
2535 GSource *source;
2536
2537 g_return_val_if_fail (tag > 0, FALSE);
2538
2539 source = g_main_context_find_source_by_id (NULL, tag);
2540 if (source)
2541 g_source_destroy (source);
2542 else
2543 g_critical ("Source ID %u was not found when attempting to remove it", tag);
2544
2545 return source != NULL;
2546 }
2547
2548 /**
2549 * g_source_remove_by_user_data:
2550 * @user_data: the user_data for the callback.
2551 *
2552 * Removes a source from the default main loop context given the user
2553 * data for the callback. If multiple sources exist with the same user
2554 * data, only one will be destroyed.
2555 *
2556 * Returns: %TRUE if a source was found and removed.
2557 **/
2558 gboolean
g_source_remove_by_user_data(gpointer user_data)2559 g_source_remove_by_user_data (gpointer user_data)
2560 {
2561 GSource *source;
2562
2563 source = g_main_context_find_source_by_user_data (NULL, user_data);
2564 if (source)
2565 {
2566 g_source_destroy (source);
2567 return TRUE;
2568 }
2569 else
2570 return FALSE;
2571 }
2572
2573 /**
2574 * g_source_remove_by_funcs_user_data:
2575 * @funcs: The @source_funcs passed to g_source_new()
2576 * @user_data: the user data for the callback
2577 *
2578 * Removes a source from the default main loop context given the
2579 * source functions and user data. If multiple sources exist with the
2580 * same source functions and user data, only one will be destroyed.
2581 *
2582 * Returns: %TRUE if a source was found and removed.
2583 **/
2584 gboolean
g_source_remove_by_funcs_user_data(GSourceFuncs * funcs,gpointer user_data)2585 g_source_remove_by_funcs_user_data (GSourceFuncs *funcs,
2586 gpointer user_data)
2587 {
2588 GSource *source;
2589
2590 g_return_val_if_fail (funcs != NULL, FALSE);
2591
2592 source = g_main_context_find_source_by_funcs_user_data (NULL, funcs, user_data);
2593 if (source)
2594 {
2595 g_source_destroy (source);
2596 return TRUE;
2597 }
2598 else
2599 return FALSE;
2600 }
2601
2602 /**
2603 * g_clear_handle_id: (skip)
2604 * @tag_ptr: (not nullable): a pointer to the handler ID
2605 * @clear_func: (not nullable): the function to call to clear the handler
2606 *
2607 * Clears a numeric handler, such as a #GSource ID.
2608 *
2609 * @tag_ptr must be a valid pointer to the variable holding the handler.
2610 *
2611 * If the ID is zero then this function does nothing.
2612 * Otherwise, clear_func() is called with the ID as a parameter, and the tag is
2613 * set to zero.
2614 *
2615 * A macro is also included that allows this function to be used without
2616 * pointer casts.
2617 *
2618 * Since: 2.56
2619 */
2620 #undef g_clear_handle_id
2621 void
g_clear_handle_id(guint * tag_ptr,GClearHandleFunc clear_func)2622 g_clear_handle_id (guint *tag_ptr,
2623 GClearHandleFunc clear_func)
2624 {
2625 guint _handle_id;
2626
2627 _handle_id = *tag_ptr;
2628 if (_handle_id > 0)
2629 {
2630 *tag_ptr = 0;
2631 clear_func (_handle_id);
2632 }
2633 }
2634
2635 #ifdef G_OS_UNIX
2636 /**
2637 * g_source_add_unix_fd:
2638 * @source: a #GSource
2639 * @fd: the fd to monitor
2640 * @events: an event mask
2641 *
2642 * Monitors @fd for the IO events in @events.
2643 *
2644 * The tag returned by this function can be used to remove or modify the
2645 * monitoring of the fd using g_source_remove_unix_fd() or
2646 * g_source_modify_unix_fd().
2647 *
2648 * It is not necessary to remove the fd before destroying the source; it
2649 * will be cleaned up automatically.
2650 *
2651 * This API is only intended to be used by implementations of #GSource.
2652 * Do not call this API on a #GSource that you did not create.
2653 *
2654 * As the name suggests, this function is not available on Windows.
2655 *
2656 * Returns: (not nullable): an opaque tag
2657 *
2658 * Since: 2.36
2659 **/
2660 gpointer
g_source_add_unix_fd(GSource * source,gint fd,GIOCondition events)2661 g_source_add_unix_fd (GSource *source,
2662 gint fd,
2663 GIOCondition events)
2664 {
2665 GMainContext *context;
2666 GPollFD *poll_fd;
2667
2668 g_return_val_if_fail (source != NULL, NULL);
2669 g_return_val_if_fail (g_atomic_int_get (&source->ref_count) > 0, NULL);
2670 g_return_val_if_fail (!SOURCE_DESTROYED (source), NULL);
2671
2672 poll_fd = g_new (GPollFD, 1);
2673 poll_fd->fd = fd;
2674 poll_fd->events = events;
2675 poll_fd->revents = 0;
2676
2677 context = source->context;
2678
2679 if (context)
2680 LOCK_CONTEXT (context);
2681
2682 source->priv->fds = g_slist_prepend (source->priv->fds, poll_fd);
2683
2684 if (context)
2685 {
2686 if (!SOURCE_BLOCKED (source))
2687 g_main_context_add_poll_unlocked (context, source->priority, poll_fd);
2688 UNLOCK_CONTEXT (context);
2689 }
2690
2691 return poll_fd;
2692 }
2693
2694 /**
2695 * g_source_modify_unix_fd:
2696 * @source: a #GSource
2697 * @tag: (not nullable): the tag from g_source_add_unix_fd()
2698 * @new_events: the new event mask to watch
2699 *
2700 * Updates the event mask to watch for the fd identified by @tag.
2701 *
2702 * @tag is the tag returned from g_source_add_unix_fd().
2703 *
2704 * If you want to remove a fd, don't set its event mask to zero.
2705 * Instead, call g_source_remove_unix_fd().
2706 *
2707 * This API is only intended to be used by implementations of #GSource.
2708 * Do not call this API on a #GSource that you did not create.
2709 *
2710 * As the name suggests, this function is not available on Windows.
2711 *
2712 * Since: 2.36
2713 **/
2714 void
g_source_modify_unix_fd(GSource * source,gpointer tag,GIOCondition new_events)2715 g_source_modify_unix_fd (GSource *source,
2716 gpointer tag,
2717 GIOCondition new_events)
2718 {
2719 GMainContext *context;
2720 GPollFD *poll_fd;
2721
2722 g_return_if_fail (source != NULL);
2723 g_return_if_fail (g_atomic_int_get (&source->ref_count) > 0);
2724 g_return_if_fail (g_slist_find (source->priv->fds, tag));
2725
2726 context = source->context;
2727 poll_fd = tag;
2728
2729 poll_fd->events = new_events;
2730
2731 if (context)
2732 g_main_context_wakeup (context);
2733 }
2734
2735 /**
2736 * g_source_remove_unix_fd:
2737 * @source: a #GSource
2738 * @tag: (not nullable): the tag from g_source_add_unix_fd()
2739 *
2740 * Reverses the effect of a previous call to g_source_add_unix_fd().
2741 *
2742 * You only need to call this if you want to remove an fd from being
2743 * watched while keeping the same source around. In the normal case you
2744 * will just want to destroy the source.
2745 *
2746 * This API is only intended to be used by implementations of #GSource.
2747 * Do not call this API on a #GSource that you did not create.
2748 *
2749 * As the name suggests, this function is not available on Windows.
2750 *
2751 * Since: 2.36
2752 **/
2753 void
g_source_remove_unix_fd(GSource * source,gpointer tag)2754 g_source_remove_unix_fd (GSource *source,
2755 gpointer tag)
2756 {
2757 GMainContext *context;
2758 GPollFD *poll_fd;
2759
2760 g_return_if_fail (source != NULL);
2761 g_return_if_fail (g_atomic_int_get (&source->ref_count) > 0);
2762 g_return_if_fail (g_slist_find (source->priv->fds, tag));
2763
2764 context = source->context;
2765 poll_fd = tag;
2766
2767 if (context)
2768 LOCK_CONTEXT (context);
2769
2770 source->priv->fds = g_slist_remove (source->priv->fds, poll_fd);
2771
2772 if (context)
2773 {
2774 if (!SOURCE_BLOCKED (source))
2775 g_main_context_remove_poll_unlocked (context, poll_fd);
2776
2777 UNLOCK_CONTEXT (context);
2778 }
2779
2780 g_free (poll_fd);
2781 }
2782
2783 /**
2784 * g_source_query_unix_fd:
2785 * @source: a #GSource
2786 * @tag: (not nullable): the tag from g_source_add_unix_fd()
2787 *
2788 * Queries the events reported for the fd corresponding to @tag on
2789 * @source during the last poll.
2790 *
2791 * The return value of this function is only defined when the function
2792 * is called from the check or dispatch functions for @source.
2793 *
2794 * This API is only intended to be used by implementations of #GSource.
2795 * Do not call this API on a #GSource that you did not create.
2796 *
2797 * As the name suggests, this function is not available on Windows.
2798 *
2799 * Returns: the conditions reported on the fd
2800 *
2801 * Since: 2.36
2802 **/
2803 GIOCondition
g_source_query_unix_fd(GSource * source,gpointer tag)2804 g_source_query_unix_fd (GSource *source,
2805 gpointer tag)
2806 {
2807 GPollFD *poll_fd;
2808
2809 g_return_val_if_fail (source != NULL, 0);
2810 g_return_val_if_fail (g_atomic_int_get (&source->ref_count) > 0, 0);
2811 g_return_val_if_fail (g_slist_find (source->priv->fds, tag), 0);
2812
2813 poll_fd = tag;
2814
2815 return poll_fd->revents;
2816 }
2817 #endif /* G_OS_UNIX */
2818
2819 /**
2820 * g_get_current_time:
2821 * @result: #GTimeVal structure in which to store current time.
2822 *
2823 * Equivalent to the UNIX gettimeofday() function, but portable.
2824 *
2825 * You may find g_get_real_time() to be more convenient.
2826 *
2827 * Deprecated: 2.62: #GTimeVal is not year-2038-safe. Use g_get_real_time()
2828 * instead.
2829 **/
2830 G_GNUC_BEGIN_IGNORE_DEPRECATIONS
2831 void
g_get_current_time(GTimeVal * result)2832 g_get_current_time (GTimeVal *result)
2833 {
2834 gint64 tv;
2835
2836 g_return_if_fail (result != NULL);
2837
2838 tv = g_get_real_time ();
2839
2840 result->tv_sec = tv / 1000000;
2841 result->tv_usec = tv % 1000000;
2842 }
2843 G_GNUC_END_IGNORE_DEPRECATIONS
2844
2845 /**
2846 * g_get_real_time:
2847 *
2848 * Queries the system wall-clock time.
2849 *
2850 * This call is functionally equivalent to g_get_current_time() except
2851 * that the return value is often more convenient than dealing with a
2852 * #GTimeVal.
2853 *
2854 * You should only use this call if you are actually interested in the real
2855 * wall-clock time. g_get_monotonic_time() is probably more useful for
2856 * measuring intervals.
2857 *
2858 * Returns: the number of microseconds since January 1, 1970 UTC.
2859 *
2860 * Since: 2.28
2861 **/
2862 gint64
g_get_real_time(void)2863 g_get_real_time (void)
2864 {
2865 #ifndef G_OS_WIN32
2866 struct timeval r;
2867
2868 /* this is required on alpha, there the timeval structs are ints
2869 * not longs and a cast only would fail horribly */
2870 gettimeofday (&r, NULL);
2871
2872 return (((gint64) r.tv_sec) * 1000000) + r.tv_usec;
2873 #else
2874 FILETIME ft;
2875 guint64 time64;
2876
2877 GetSystemTimeAsFileTime (&ft);
2878 memmove (&time64, &ft, sizeof (FILETIME));
2879
2880 /* Convert from 100s of nanoseconds since 1601-01-01
2881 * to Unix epoch. This is Y2038 safe.
2882 */
2883 time64 -= G_GINT64_CONSTANT (116444736000000000);
2884 time64 /= 10;
2885
2886 return time64;
2887 #endif
2888 }
2889
2890 /**
2891 * g_get_monotonic_time:
2892 *
2893 * Queries the system monotonic time.
2894 *
2895 * The monotonic clock will always increase and doesn't suffer
2896 * discontinuities when the user (or NTP) changes the system time. It
2897 * may or may not continue to tick during times where the machine is
2898 * suspended.
2899 *
2900 * We try to use the clock that corresponds as closely as possible to
2901 * the passage of time as measured by system calls such as poll() but it
2902 * may not always be possible to do this.
2903 *
2904 * Returns: the monotonic time, in microseconds
2905 *
2906 * Since: 2.28
2907 **/
2908 #if defined (G_OS_WIN32)
2909 /* NOTE:
2910 * time_usec = ticks_since_boot * usec_per_sec / ticks_per_sec
2911 *
2912 * Doing (ticks_since_boot * usec_per_sec) before the division can overflow 64 bits
2913 * (ticks_since_boot / ticks_per_sec) and then multiply would not be accurate enough.
2914 * So for now we calculate (usec_per_sec / ticks_per_sec) and use floating point
2915 */
2916 static gdouble g_monotonic_usec_per_tick = 0;
2917
2918 void
g_clock_win32_init(void)2919 g_clock_win32_init (void)
2920 {
2921 LARGE_INTEGER freq;
2922
2923 if (!QueryPerformanceFrequency (&freq) || freq.QuadPart == 0)
2924 {
2925 /* The documentation says that this should never happen */
2926 g_assert_not_reached ();
2927 return;
2928 }
2929
2930 g_monotonic_usec_per_tick = (gdouble)G_USEC_PER_SEC / freq.QuadPart;
2931 }
2932
2933 gint64
g_get_monotonic_time(void)2934 g_get_monotonic_time (void)
2935 {
2936 if (G_LIKELY (g_monotonic_usec_per_tick != 0))
2937 {
2938 LARGE_INTEGER ticks;
2939
2940 if (QueryPerformanceCounter (&ticks))
2941 return (gint64)(ticks.QuadPart * g_monotonic_usec_per_tick);
2942
2943 g_warning ("QueryPerformanceCounter Failed (%lu)", GetLastError ());
2944 g_monotonic_usec_per_tick = 0;
2945 }
2946
2947 return 0;
2948 }
2949 #elif defined(HAVE_MACH_MACH_TIME_H) /* Mac OS */
2950 gint64
g_get_monotonic_time(void)2951 g_get_monotonic_time (void)
2952 {
2953 mach_timebase_info_data_t timebase_info;
2954 guint64 val;
2955
2956 /* we get nanoseconds from mach_absolute_time() using timebase_info */
2957 mach_timebase_info (&timebase_info);
2958 val = mach_absolute_time ();
2959
2960 if (timebase_info.numer != timebase_info.denom)
2961 {
2962 #ifdef HAVE_UINT128_T
2963 val = ((__uint128_t) val * (__uint128_t) timebase_info.numer) / timebase_info.denom / 1000;
2964 #else
2965 guint64 t_high, t_low;
2966 guint64 result_high, result_low;
2967
2968 /* 64 bit x 32 bit / 32 bit with 96-bit intermediate
2969 * algorithm lifted from qemu */
2970 t_low = (val & 0xffffffffLL) * (guint64) timebase_info.numer;
2971 t_high = (val >> 32) * (guint64) timebase_info.numer;
2972 t_high += (t_low >> 32);
2973 result_high = t_high / (guint64) timebase_info.denom;
2974 result_low = (((t_high % (guint64) timebase_info.denom) << 32) +
2975 (t_low & 0xffffffff)) /
2976 (guint64) timebase_info.denom;
2977 val = ((result_high << 32) | result_low) / 1000;
2978 #endif
2979 }
2980 else
2981 {
2982 /* nanoseconds to microseconds */
2983 val = val / 1000;
2984 }
2985
2986 return val;
2987 }
2988 #else
2989 gint64
g_get_monotonic_time(void)2990 g_get_monotonic_time (void)
2991 {
2992 struct timespec ts;
2993 gint result;
2994
2995 result = clock_gettime (CLOCK_MONOTONIC, &ts);
2996
2997 if G_UNLIKELY (result != 0)
2998 g_error ("GLib requires working CLOCK_MONOTONIC");
2999
3000 return (((gint64) ts.tv_sec) * 1000000) + (ts.tv_nsec / 1000);
3001 }
3002 #endif
3003
3004 static void
g_main_dispatch_free(gpointer dispatch)3005 g_main_dispatch_free (gpointer dispatch)
3006 {
3007 g_free (dispatch);
3008 }
3009
3010 /* Running the main loop */
3011
3012 static GMainDispatch *
get_dispatch(void)3013 get_dispatch (void)
3014 {
3015 static GPrivate depth_private = G_PRIVATE_INIT (g_main_dispatch_free);
3016 GMainDispatch *dispatch;
3017
3018 dispatch = g_private_get (&depth_private);
3019
3020 if (!dispatch)
3021 dispatch = g_private_set_alloc0 (&depth_private, sizeof (GMainDispatch));
3022
3023 return dispatch;
3024 }
3025
3026 /**
3027 * g_main_depth:
3028 *
3029 * Returns the depth of the stack of calls to
3030 * g_main_context_dispatch() on any #GMainContext in the current thread.
3031 * That is, when called from the toplevel, it gives 0. When
3032 * called from within a callback from g_main_context_iteration()
3033 * (or g_main_loop_run(), etc.) it returns 1. When called from within
3034 * a callback to a recursive call to g_main_context_iteration(),
3035 * it returns 2. And so forth.
3036 *
3037 * This function is useful in a situation like the following:
3038 * Imagine an extremely simple "garbage collected" system.
3039 *
3040 * |[<!-- language="C" -->
3041 * static GList *free_list;
3042 *
3043 * gpointer
3044 * allocate_memory (gsize size)
3045 * {
3046 * gpointer result = g_malloc (size);
3047 * free_list = g_list_prepend (free_list, result);
3048 * return result;
3049 * }
3050 *
3051 * void
3052 * free_allocated_memory (void)
3053 * {
3054 * GList *l;
3055 * for (l = free_list; l; l = l->next);
3056 * g_free (l->data);
3057 * g_list_free (free_list);
3058 * free_list = NULL;
3059 * }
3060 *
3061 * [...]
3062 *
3063 * while (TRUE);
3064 * {
3065 * g_main_context_iteration (NULL, TRUE);
3066 * free_allocated_memory();
3067 * }
3068 * ]|
3069 *
3070 * This works from an application, however, if you want to do the same
3071 * thing from a library, it gets more difficult, since you no longer
3072 * control the main loop. You might think you can simply use an idle
3073 * function to make the call to free_allocated_memory(), but that
3074 * doesn't work, since the idle function could be called from a
3075 * recursive callback. This can be fixed by using g_main_depth()
3076 *
3077 * |[<!-- language="C" -->
3078 * gpointer
3079 * allocate_memory (gsize size)
3080 * {
3081 * FreeListBlock *block = g_new (FreeListBlock, 1);
3082 * block->mem = g_malloc (size);
3083 * block->depth = g_main_depth ();
3084 * free_list = g_list_prepend (free_list, block);
3085 * return block->mem;
3086 * }
3087 *
3088 * void
3089 * free_allocated_memory (void)
3090 * {
3091 * GList *l;
3092 *
3093 * int depth = g_main_depth ();
3094 * for (l = free_list; l; );
3095 * {
3096 * GList *next = l->next;
3097 * FreeListBlock *block = l->data;
3098 * if (block->depth > depth)
3099 * {
3100 * g_free (block->mem);
3101 * g_free (block);
3102 * free_list = g_list_delete_link (free_list, l);
3103 * }
3104 *
3105 * l = next;
3106 * }
3107 * }
3108 * ]|
3109 *
3110 * There is a temptation to use g_main_depth() to solve
3111 * problems with reentrancy. For instance, while waiting for data
3112 * to be received from the network in response to a menu item,
3113 * the menu item might be selected again. It might seem that
3114 * one could make the menu item's callback return immediately
3115 * and do nothing if g_main_depth() returns a value greater than 1.
3116 * However, this should be avoided since the user then sees selecting
3117 * the menu item do nothing. Furthermore, you'll find yourself adding
3118 * these checks all over your code, since there are doubtless many,
3119 * many things that the user could do. Instead, you can use the
3120 * following techniques:
3121 *
3122 * 1. Use gtk_widget_set_sensitive() or modal dialogs to prevent
3123 * the user from interacting with elements while the main
3124 * loop is recursing.
3125 *
3126 * 2. Avoid main loop recursion in situations where you can't handle
3127 * arbitrary callbacks. Instead, structure your code so that you
3128 * simply return to the main loop and then get called again when
3129 * there is more work to do.
3130 *
3131 * Returns: The main loop recursion level in the current thread
3132 */
3133 int
g_main_depth(void)3134 g_main_depth (void)
3135 {
3136 GMainDispatch *dispatch = get_dispatch ();
3137 return dispatch->depth;
3138 }
3139
3140 /**
3141 * g_main_current_source:
3142 *
3143 * Returns the currently firing source for this thread.
3144 *
3145 * Returns: (transfer none) (nullable): The currently firing source or %NULL.
3146 *
3147 * Since: 2.12
3148 */
3149 GSource *
g_main_current_source(void)3150 g_main_current_source (void)
3151 {
3152 GMainDispatch *dispatch = get_dispatch ();
3153 return dispatch->source;
3154 }
3155
3156 /**
3157 * g_source_is_destroyed:
3158 * @source: a #GSource
3159 *
3160 * Returns whether @source has been destroyed.
3161 *
3162 * This is important when you operate upon your objects
3163 * from within idle handlers, but may have freed the object
3164 * before the dispatch of your idle handler.
3165 *
3166 * |[<!-- language="C" -->
3167 * static gboolean
3168 * idle_callback (gpointer data)
3169 * {
3170 * SomeWidget *self = data;
3171 *
3172 * g_mutex_lock (&self->idle_id_mutex);
3173 * // do stuff with self
3174 * self->idle_id = 0;
3175 * g_mutex_unlock (&self->idle_id_mutex);
3176 *
3177 * return G_SOURCE_REMOVE;
3178 * }
3179 *
3180 * static void
3181 * some_widget_do_stuff_later (SomeWidget *self)
3182 * {
3183 * g_mutex_lock (&self->idle_id_mutex);
3184 * self->idle_id = g_idle_add (idle_callback, self);
3185 * g_mutex_unlock (&self->idle_id_mutex);
3186 * }
3187 *
3188 * static void
3189 * some_widget_init (SomeWidget *self)
3190 * {
3191 * g_mutex_init (&self->idle_id_mutex);
3192 *
3193 * // ...
3194 * }
3195 *
3196 * static void
3197 * some_widget_finalize (GObject *object)
3198 * {
3199 * SomeWidget *self = SOME_WIDGET (object);
3200 *
3201 * if (self->idle_id)
3202 * g_source_remove (self->idle_id);
3203 *
3204 * g_mutex_clear (&self->idle_id_mutex);
3205 *
3206 * G_OBJECT_CLASS (parent_class)->finalize (object);
3207 * }
3208 * ]|
3209 *
3210 * This will fail in a multi-threaded application if the
3211 * widget is destroyed before the idle handler fires due
3212 * to the use after free in the callback. A solution, to
3213 * this particular problem, is to check to if the source
3214 * has already been destroy within the callback.
3215 *
3216 * |[<!-- language="C" -->
3217 * static gboolean
3218 * idle_callback (gpointer data)
3219 * {
3220 * SomeWidget *self = data;
3221 *
3222 * g_mutex_lock (&self->idle_id_mutex);
3223 * if (!g_source_is_destroyed (g_main_current_source ()))
3224 * {
3225 * // do stuff with self
3226 * }
3227 * g_mutex_unlock (&self->idle_id_mutex);
3228 *
3229 * return FALSE;
3230 * }
3231 * ]|
3232 *
3233 * Calls to this function from a thread other than the one acquired by the
3234 * #GMainContext the #GSource is attached to are typically redundant, as the
3235 * source could be destroyed immediately after this function returns. However,
3236 * once a source is destroyed it cannot be un-destroyed, so this function can be
3237 * used for opportunistic checks from any thread.
3238 *
3239 * Returns: %TRUE if the source has been destroyed
3240 *
3241 * Since: 2.12
3242 */
3243 gboolean
g_source_is_destroyed(GSource * source)3244 g_source_is_destroyed (GSource *source)
3245 {
3246 g_return_val_if_fail (source != NULL, TRUE);
3247 g_return_val_if_fail (g_atomic_int_get (&source->ref_count) > 0, TRUE);
3248 return SOURCE_DESTROYED (source);
3249 }
3250
3251 /* Temporarily remove all this source's file descriptors from the
3252 * poll(), so that if data comes available for one of the file descriptors
3253 * we don't continually spin in the poll()
3254 */
3255 /* HOLDS: source->context's lock */
3256 static void
block_source(GSource * source)3257 block_source (GSource *source)
3258 {
3259 GSList *tmp_list;
3260
3261 g_return_if_fail (!SOURCE_BLOCKED (source));
3262
3263 source->flags |= G_SOURCE_BLOCKED;
3264
3265 if (source->context)
3266 {
3267 tmp_list = source->poll_fds;
3268 while (tmp_list)
3269 {
3270 g_main_context_remove_poll_unlocked (source->context, tmp_list->data);
3271 tmp_list = tmp_list->next;
3272 }
3273
3274 for (tmp_list = source->priv->fds; tmp_list; tmp_list = tmp_list->next)
3275 g_main_context_remove_poll_unlocked (source->context, tmp_list->data);
3276 }
3277
3278 if (source->priv && source->priv->child_sources)
3279 {
3280 tmp_list = source->priv->child_sources;
3281 while (tmp_list)
3282 {
3283 block_source (tmp_list->data);
3284 tmp_list = tmp_list->next;
3285 }
3286 }
3287 }
3288
3289 /* HOLDS: source->context's lock */
3290 static void
unblock_source(GSource * source)3291 unblock_source (GSource *source)
3292 {
3293 GSList *tmp_list;
3294
3295 g_return_if_fail (SOURCE_BLOCKED (source)); /* Source already unblocked */
3296 g_return_if_fail (!SOURCE_DESTROYED (source));
3297
3298 source->flags &= ~G_SOURCE_BLOCKED;
3299
3300 tmp_list = source->poll_fds;
3301 while (tmp_list)
3302 {
3303 g_main_context_add_poll_unlocked (source->context, source->priority, tmp_list->data);
3304 tmp_list = tmp_list->next;
3305 }
3306
3307 for (tmp_list = source->priv->fds; tmp_list; tmp_list = tmp_list->next)
3308 g_main_context_add_poll_unlocked (source->context, source->priority, tmp_list->data);
3309
3310 if (source->priv && source->priv->child_sources)
3311 {
3312 tmp_list = source->priv->child_sources;
3313 while (tmp_list)
3314 {
3315 unblock_source (tmp_list->data);
3316 tmp_list = tmp_list->next;
3317 }
3318 }
3319 }
3320
3321 /* HOLDS: context's lock */
3322 static void
g_main_dispatch(GMainContext * context)3323 g_main_dispatch (GMainContext *context)
3324 {
3325 GMainDispatch *current = get_dispatch ();
3326 guint i;
3327
3328 for (i = 0; i < context->pending_dispatches->len; i++)
3329 {
3330 GSource *source = context->pending_dispatches->pdata[i];
3331
3332 context->pending_dispatches->pdata[i] = NULL;
3333 g_assert (source);
3334
3335 source->flags &= ~G_SOURCE_READY;
3336
3337 if (!SOURCE_DESTROYED (source))
3338 {
3339 gboolean was_in_call;
3340 gpointer user_data = NULL;
3341 GSourceFunc callback = NULL;
3342 GSourceCallbackFuncs *cb_funcs;
3343 gpointer cb_data;
3344 gboolean need_destroy;
3345
3346 gboolean (*dispatch) (GSource *,
3347 GSourceFunc,
3348 gpointer);
3349 GSource *prev_source;
3350 gint64 begin_time_nsec G_GNUC_UNUSED;
3351
3352 dispatch = source->source_funcs->dispatch;
3353 cb_funcs = source->callback_funcs;
3354 cb_data = source->callback_data;
3355
3356 if (cb_funcs)
3357 cb_funcs->ref (cb_data);
3358
3359 if ((source->flags & G_SOURCE_CAN_RECURSE) == 0)
3360 block_source (source);
3361
3362 was_in_call = source->flags & G_HOOK_FLAG_IN_CALL;
3363 source->flags |= G_HOOK_FLAG_IN_CALL;
3364
3365 if (cb_funcs)
3366 cb_funcs->get (cb_data, source, &callback, &user_data);
3367
3368 UNLOCK_CONTEXT (context);
3369
3370 /* These operations are safe because 'current' is thread-local
3371 * and not modified from anywhere but this function.
3372 */
3373 prev_source = current->source;
3374 current->source = source;
3375 current->depth++;
3376
3377 begin_time_nsec = G_TRACE_CURRENT_TIME;
3378
3379 TRACE (GLIB_MAIN_BEFORE_DISPATCH (g_source_get_name (source), source,
3380 dispatch, callback, user_data));
3381 need_destroy = !(* dispatch) (source, callback, user_data);
3382 TRACE (GLIB_MAIN_AFTER_DISPATCH (g_source_get_name (source), source,
3383 dispatch, need_destroy));
3384
3385 g_trace_mark (begin_time_nsec, G_TRACE_CURRENT_TIME - begin_time_nsec,
3386 "GLib", "GSource.dispatch",
3387 "%s ⇒ %s",
3388 (g_source_get_name (source) != NULL) ? g_source_get_name (source) : "(unnamed)",
3389 need_destroy ? "destroy" : "keep");
3390
3391 current->source = prev_source;
3392 current->depth--;
3393
3394 if (cb_funcs)
3395 cb_funcs->unref (cb_data);
3396
3397 LOCK_CONTEXT (context);
3398
3399 if (!was_in_call)
3400 source->flags &= ~G_HOOK_FLAG_IN_CALL;
3401
3402 if (SOURCE_BLOCKED (source) && !SOURCE_DESTROYED (source))
3403 unblock_source (source);
3404
3405 /* Note: this depends on the fact that we can't switch
3406 * sources from one main context to another
3407 */
3408 if (need_destroy && !SOURCE_DESTROYED (source))
3409 {
3410 g_assert (source->context == context);
3411 g_source_destroy_internal (source, context, TRUE);
3412 }
3413 }
3414
3415 g_source_unref_internal (source, context, TRUE);
3416 }
3417
3418 g_ptr_array_set_size (context->pending_dispatches, 0);
3419 }
3420
3421 /**
3422 * g_main_context_acquire:
3423 * @context: a #GMainContext
3424 *
3425 * Tries to become the owner of the specified context.
3426 * If some other thread is the owner of the context,
3427 * returns %FALSE immediately. Ownership is properly
3428 * recursive: the owner can require ownership again
3429 * and will release ownership when g_main_context_release()
3430 * is called as many times as g_main_context_acquire().
3431 *
3432 * You must be the owner of a context before you
3433 * can call g_main_context_prepare(), g_main_context_query(),
3434 * g_main_context_check(), g_main_context_dispatch().
3435 *
3436 * Returns: %TRUE if the operation succeeded, and
3437 * this thread is now the owner of @context.
3438 **/
3439 gboolean
g_main_context_acquire(GMainContext * context)3440 g_main_context_acquire (GMainContext *context)
3441 {
3442 gboolean result = FALSE;
3443 GThread *self = G_THREAD_SELF;
3444
3445 if (context == NULL)
3446 context = g_main_context_default ();
3447
3448 LOCK_CONTEXT (context);
3449
3450 if (!context->owner)
3451 {
3452 context->owner = self;
3453 g_assert (context->owner_count == 0);
3454 TRACE (GLIB_MAIN_CONTEXT_ACQUIRE (context, TRUE /* success */));
3455 }
3456
3457 if (context->owner == self)
3458 {
3459 context->owner_count++;
3460 result = TRUE;
3461 }
3462 else
3463 {
3464 TRACE (GLIB_MAIN_CONTEXT_ACQUIRE (context, FALSE /* failure */));
3465 }
3466
3467 UNLOCK_CONTEXT (context);
3468
3469 return result;
3470 }
3471
3472 /**
3473 * g_main_context_release:
3474 * @context: a #GMainContext
3475 *
3476 * Releases ownership of a context previously acquired by this thread
3477 * with g_main_context_acquire(). If the context was acquired multiple
3478 * times, the ownership will be released only when g_main_context_release()
3479 * is called as many times as it was acquired.
3480 **/
3481 void
g_main_context_release(GMainContext * context)3482 g_main_context_release (GMainContext *context)
3483 {
3484 if (context == NULL)
3485 context = g_main_context_default ();
3486
3487 LOCK_CONTEXT (context);
3488
3489 context->owner_count--;
3490 if (context->owner_count == 0)
3491 {
3492 TRACE (GLIB_MAIN_CONTEXT_RELEASE (context));
3493
3494 context->owner = NULL;
3495
3496 if (context->waiters)
3497 {
3498 GMainWaiter *waiter = context->waiters->data;
3499 gboolean loop_internal_waiter = (waiter->mutex == &context->mutex);
3500 context->waiters = g_slist_delete_link (context->waiters,
3501 context->waiters);
3502 if (!loop_internal_waiter)
3503 g_mutex_lock (waiter->mutex);
3504
3505 g_cond_signal (waiter->cond);
3506
3507 if (!loop_internal_waiter)
3508 g_mutex_unlock (waiter->mutex);
3509 }
3510 }
3511
3512 UNLOCK_CONTEXT (context);
3513 }
3514
3515 static gboolean
g_main_context_wait_internal(GMainContext * context,GCond * cond,GMutex * mutex)3516 g_main_context_wait_internal (GMainContext *context,
3517 GCond *cond,
3518 GMutex *mutex)
3519 {
3520 gboolean result = FALSE;
3521 GThread *self = G_THREAD_SELF;
3522 gboolean loop_internal_waiter;
3523
3524 if (context == NULL)
3525 context = g_main_context_default ();
3526
3527 loop_internal_waiter = (mutex == &context->mutex);
3528
3529 if (!loop_internal_waiter)
3530 LOCK_CONTEXT (context);
3531
3532 if (context->owner && context->owner != self)
3533 {
3534 GMainWaiter waiter;
3535
3536 waiter.cond = cond;
3537 waiter.mutex = mutex;
3538
3539 context->waiters = g_slist_append (context->waiters, &waiter);
3540
3541 if (!loop_internal_waiter)
3542 UNLOCK_CONTEXT (context);
3543 g_cond_wait (cond, mutex);
3544 if (!loop_internal_waiter)
3545 LOCK_CONTEXT (context);
3546
3547 context->waiters = g_slist_remove (context->waiters, &waiter);
3548 }
3549
3550 if (!context->owner)
3551 {
3552 context->owner = self;
3553 g_assert (context->owner_count == 0);
3554 }
3555
3556 if (context->owner == self)
3557 {
3558 context->owner_count++;
3559 result = TRUE;
3560 }
3561
3562 if (!loop_internal_waiter)
3563 UNLOCK_CONTEXT (context);
3564
3565 return result;
3566 }
3567
3568 /**
3569 * g_main_context_wait:
3570 * @context: a #GMainContext
3571 * @cond: a condition variable
3572 * @mutex: a mutex, currently held
3573 *
3574 * Tries to become the owner of the specified context,
3575 * as with g_main_context_acquire(). But if another thread
3576 * is the owner, atomically drop @mutex and wait on @cond until
3577 * that owner releases ownership or until @cond is signaled, then
3578 * try again (once) to become the owner.
3579 *
3580 * Returns: %TRUE if the operation succeeded, and
3581 * this thread is now the owner of @context.
3582 * Deprecated: 2.58: Use g_main_context_is_owner() and separate locking instead.
3583 */
3584 gboolean
g_main_context_wait(GMainContext * context,GCond * cond,GMutex * mutex)3585 g_main_context_wait (GMainContext *context,
3586 GCond *cond,
3587 GMutex *mutex)
3588 {
3589 if (context == NULL)
3590 context = g_main_context_default ();
3591
3592 if (G_UNLIKELY (cond != &context->cond || mutex != &context->mutex))
3593 {
3594 static gboolean warned;
3595
3596 if (!warned)
3597 {
3598 g_critical ("WARNING!! g_main_context_wait() will be removed in a future release. "
3599 "If you see this message, please file a bug immediately.");
3600 warned = TRUE;
3601 }
3602 }
3603
3604 return g_main_context_wait_internal (context, cond, mutex);
3605 }
3606
3607 /**
3608 * g_main_context_prepare:
3609 * @context: a #GMainContext
3610 * @priority: (out) (optional): location to store priority of highest priority
3611 * source already ready.
3612 *
3613 * Prepares to poll sources within a main loop. The resulting information
3614 * for polling is determined by calling g_main_context_query ().
3615 *
3616 * You must have successfully acquired the context with
3617 * g_main_context_acquire() before you may call this function.
3618 *
3619 * Returns: %TRUE if some source is ready to be dispatched
3620 * prior to polling.
3621 **/
3622 gboolean
g_main_context_prepare(GMainContext * context,gint * priority)3623 g_main_context_prepare (GMainContext *context,
3624 gint *priority)
3625 {
3626 guint i;
3627 gint n_ready = 0;
3628 gint current_priority = G_MAXINT;
3629 GSource *source;
3630 GSourceIter iter;
3631
3632 if (context == NULL)
3633 context = g_main_context_default ();
3634
3635 LOCK_CONTEXT (context);
3636
3637 context->time_is_fresh = FALSE;
3638
3639 if (context->in_check_or_prepare)
3640 {
3641 g_warning ("g_main_context_prepare() called recursively from within a source's check() or "
3642 "prepare() member.");
3643 UNLOCK_CONTEXT (context);
3644 return FALSE;
3645 }
3646
3647 TRACE (GLIB_MAIN_CONTEXT_BEFORE_PREPARE (context));
3648
3649 #if 0
3650 /* If recursing, finish up current dispatch, before starting over */
3651 if (context->pending_dispatches)
3652 {
3653 if (dispatch)
3654 g_main_dispatch (context, ¤t_time);
3655
3656 UNLOCK_CONTEXT (context);
3657 return TRUE;
3658 }
3659 #endif
3660
3661 /* If recursing, clear list of pending dispatches */
3662
3663 for (i = 0; i < context->pending_dispatches->len; i++)
3664 {
3665 if (context->pending_dispatches->pdata[i])
3666 g_source_unref_internal ((GSource *)context->pending_dispatches->pdata[i], context, TRUE);
3667 }
3668 g_ptr_array_set_size (context->pending_dispatches, 0);
3669
3670 /* Prepare all sources */
3671
3672 context->timeout = -1;
3673
3674 g_source_iter_init (&iter, context, TRUE);
3675 while (g_source_iter_next (&iter, &source))
3676 {
3677 gint source_timeout = -1;
3678
3679 if (SOURCE_DESTROYED (source) || SOURCE_BLOCKED (source))
3680 continue;
3681 if ((n_ready > 0) && (source->priority > current_priority))
3682 break;
3683
3684 if (!(source->flags & G_SOURCE_READY))
3685 {
3686 gboolean result;
3687 gboolean (* prepare) (GSource *source,
3688 gint *timeout);
3689
3690 prepare = source->source_funcs->prepare;
3691
3692 if (prepare)
3693 {
3694 gint64 begin_time_nsec G_GNUC_UNUSED;
3695
3696 context->in_check_or_prepare++;
3697 UNLOCK_CONTEXT (context);
3698
3699 begin_time_nsec = G_TRACE_CURRENT_TIME;
3700
3701 result = (* prepare) (source, &source_timeout);
3702 TRACE (GLIB_MAIN_AFTER_PREPARE (source, prepare, source_timeout));
3703
3704 g_trace_mark (begin_time_nsec, G_TRACE_CURRENT_TIME - begin_time_nsec,
3705 "GLib", "GSource.prepare",
3706 "%s ⇒ %s",
3707 (g_source_get_name (source) != NULL) ? g_source_get_name (source) : "(unnamed)",
3708 result ? "ready" : "unready");
3709
3710 LOCK_CONTEXT (context);
3711 context->in_check_or_prepare--;
3712 }
3713 else
3714 {
3715 source_timeout = -1;
3716 result = FALSE;
3717 }
3718
3719 if (result == FALSE && source->priv->ready_time != -1)
3720 {
3721 if (!context->time_is_fresh)
3722 {
3723 context->time = g_get_monotonic_time ();
3724 context->time_is_fresh = TRUE;
3725 }
3726
3727 if (source->priv->ready_time <= context->time)
3728 {
3729 source_timeout = 0;
3730 result = TRUE;
3731 }
3732 else
3733 {
3734 gint64 timeout;
3735
3736 /* rounding down will lead to spinning, so always round up */
3737 timeout = (source->priv->ready_time - context->time + 999) / 1000;
3738
3739 if (source_timeout < 0 || timeout < source_timeout)
3740 source_timeout = MIN (timeout, G_MAXINT);
3741 }
3742 }
3743
3744 if (result)
3745 {
3746 GSource *ready_source = source;
3747
3748 while (ready_source)
3749 {
3750 ready_source->flags |= G_SOURCE_READY;
3751 ready_source = ready_source->priv->parent_source;
3752 }
3753 }
3754 }
3755
3756 if (source->flags & G_SOURCE_READY)
3757 {
3758 n_ready++;
3759 current_priority = source->priority;
3760 context->timeout = 0;
3761 }
3762
3763 if (source_timeout >= 0)
3764 {
3765 if (context->timeout < 0)
3766 context->timeout = source_timeout;
3767 else
3768 context->timeout = MIN (context->timeout, source_timeout);
3769 }
3770 }
3771 g_source_iter_clear (&iter);
3772
3773 TRACE (GLIB_MAIN_CONTEXT_AFTER_PREPARE (context, current_priority, n_ready));
3774
3775 UNLOCK_CONTEXT (context);
3776
3777 if (priority)
3778 *priority = current_priority;
3779
3780 return (n_ready > 0);
3781 }
3782
3783 /**
3784 * g_main_context_query:
3785 * @context: a #GMainContext
3786 * @max_priority: maximum priority source to check
3787 * @timeout_: (out): location to store timeout to be used in polling
3788 * @fds: (out caller-allocates) (array length=n_fds): location to
3789 * store #GPollFD records that need to be polled.
3790 * @n_fds: (in): length of @fds.
3791 *
3792 * Determines information necessary to poll this main loop. You should
3793 * be careful to pass the resulting @fds array and its length @n_fds
3794 * as is when calling g_main_context_check(), as this function relies
3795 * on assumptions made when the array is filled.
3796 *
3797 * You must have successfully acquired the context with
3798 * g_main_context_acquire() before you may call this function.
3799 *
3800 * Returns: the number of records actually stored in @fds,
3801 * or, if more than @n_fds records need to be stored, the number
3802 * of records that need to be stored.
3803 **/
3804 gint
g_main_context_query(GMainContext * context,gint max_priority,gint * timeout,GPollFD * fds,gint n_fds)3805 g_main_context_query (GMainContext *context,
3806 gint max_priority,
3807 gint *timeout,
3808 GPollFD *fds,
3809 gint n_fds)
3810 {
3811 gint n_poll;
3812 GPollRec *pollrec, *lastpollrec;
3813 gushort events;
3814
3815 LOCK_CONTEXT (context);
3816
3817 TRACE (GLIB_MAIN_CONTEXT_BEFORE_QUERY (context, max_priority));
3818
3819 /* fds is filled sequentially from poll_records. Since poll_records
3820 * are incrementally sorted by file descriptor identifier, fds will
3821 * also be incrementally sorted.
3822 */
3823 n_poll = 0;
3824 lastpollrec = NULL;
3825 for (pollrec = context->poll_records; pollrec; pollrec = pollrec->next)
3826 {
3827 if (pollrec->priority > max_priority)
3828 continue;
3829
3830 /* In direct contradiction to the Unix98 spec, IRIX runs into
3831 * difficulty if you pass in POLLERR, POLLHUP or POLLNVAL
3832 * flags in the events field of the pollfd while it should
3833 * just ignoring them. So we mask them out here.
3834 */
3835 events = pollrec->fd->events & ~(G_IO_ERR|G_IO_HUP|G_IO_NVAL);
3836
3837 /* This optimization --using the same GPollFD to poll for more
3838 * than one poll record-- relies on the poll records being
3839 * incrementally sorted.
3840 */
3841 if (lastpollrec && pollrec->fd->fd == lastpollrec->fd->fd)
3842 {
3843 if (n_poll - 1 < n_fds)
3844 fds[n_poll - 1].events |= events;
3845 }
3846 else
3847 {
3848 if (n_poll < n_fds)
3849 {
3850 fds[n_poll].fd = pollrec->fd->fd;
3851 fds[n_poll].events = events;
3852 fds[n_poll].revents = 0;
3853 }
3854
3855 n_poll++;
3856 }
3857
3858 lastpollrec = pollrec;
3859 }
3860
3861 context->poll_changed = FALSE;
3862
3863 if (timeout)
3864 {
3865 *timeout = context->timeout;
3866 if (*timeout != 0)
3867 context->time_is_fresh = FALSE;
3868 }
3869
3870 TRACE (GLIB_MAIN_CONTEXT_AFTER_QUERY (context, context->timeout,
3871 fds, n_poll));
3872
3873 UNLOCK_CONTEXT (context);
3874
3875 return n_poll;
3876 }
3877
3878 /**
3879 * g_main_context_check:
3880 * @context: a #GMainContext
3881 * @max_priority: the maximum numerical priority of sources to check
3882 * @fds: (array length=n_fds): array of #GPollFD's that was passed to
3883 * the last call to g_main_context_query()
3884 * @n_fds: return value of g_main_context_query()
3885 *
3886 * Passes the results of polling back to the main loop. You should be
3887 * careful to pass @fds and its length @n_fds as received from
3888 * g_main_context_query(), as this functions relies on assumptions
3889 * on how @fds is filled.
3890 *
3891 * You must have successfully acquired the context with
3892 * g_main_context_acquire() before you may call this function.
3893 *
3894 * Returns: %TRUE if some sources are ready to be dispatched.
3895 **/
3896 gboolean
g_main_context_check(GMainContext * context,gint max_priority,GPollFD * fds,gint n_fds)3897 g_main_context_check (GMainContext *context,
3898 gint max_priority,
3899 GPollFD *fds,
3900 gint n_fds)
3901 {
3902 GSource *source;
3903 GSourceIter iter;
3904 GPollRec *pollrec;
3905 gint n_ready = 0;
3906 gint i;
3907
3908 LOCK_CONTEXT (context);
3909
3910 if (context->in_check_or_prepare)
3911 {
3912 g_warning ("g_main_context_check() called recursively from within a source's check() or "
3913 "prepare() member.");
3914 UNLOCK_CONTEXT (context);
3915 return FALSE;
3916 }
3917
3918 TRACE (GLIB_MAIN_CONTEXT_BEFORE_CHECK (context, max_priority, fds, n_fds));
3919
3920 for (i = 0; i < n_fds; i++)
3921 {
3922 if (fds[i].fd == context->wake_up_rec.fd)
3923 {
3924 if (fds[i].revents)
3925 {
3926 TRACE (GLIB_MAIN_CONTEXT_WAKEUP_ACKNOWLEDGE (context));
3927 g_wakeup_acknowledge (context->wakeup);
3928 }
3929 break;
3930 }
3931 }
3932
3933 /* If the set of poll file descriptors changed, bail out
3934 * and let the main loop rerun
3935 */
3936 if (context->poll_changed)
3937 {
3938 TRACE (GLIB_MAIN_CONTEXT_AFTER_CHECK (context, 0));
3939
3940 UNLOCK_CONTEXT (context);
3941 return FALSE;
3942 }
3943
3944 /* The linear iteration below relies on the assumption that both
3945 * poll records and the fds array are incrementally sorted by file
3946 * descriptor identifier.
3947 */
3948 pollrec = context->poll_records;
3949 i = 0;
3950 while (pollrec && i < n_fds)
3951 {
3952 /* Make sure that fds is sorted by file descriptor identifier. */
3953 g_assert (i <= 0 || fds[i - 1].fd < fds[i].fd);
3954
3955 /* Skip until finding the first GPollRec matching the current GPollFD. */
3956 while (pollrec && pollrec->fd->fd != fds[i].fd)
3957 pollrec = pollrec->next;
3958
3959 /* Update all consecutive GPollRecs that match. */
3960 while (pollrec && pollrec->fd->fd == fds[i].fd)
3961 {
3962 if (pollrec->priority <= max_priority)
3963 {
3964 pollrec->fd->revents =
3965 fds[i].revents & (pollrec->fd->events | G_IO_ERR | G_IO_HUP | G_IO_NVAL);
3966 }
3967 pollrec = pollrec->next;
3968 }
3969
3970 /* Iterate to next GPollFD. */
3971 i++;
3972 }
3973
3974 g_source_iter_init (&iter, context, TRUE);
3975 while (g_source_iter_next (&iter, &source))
3976 {
3977 if (SOURCE_DESTROYED (source) || SOURCE_BLOCKED (source))
3978 continue;
3979 if ((n_ready > 0) && (source->priority > max_priority))
3980 break;
3981
3982 if (!(source->flags & G_SOURCE_READY))
3983 {
3984 gboolean result;
3985 gboolean (* check) (GSource *source);
3986
3987 check = source->source_funcs->check;
3988
3989 if (check)
3990 {
3991 gint64 begin_time_nsec G_GNUC_UNUSED;
3992
3993 /* If the check function is set, call it. */
3994 context->in_check_or_prepare++;
3995 UNLOCK_CONTEXT (context);
3996
3997 begin_time_nsec = G_TRACE_CURRENT_TIME;
3998
3999 result = (* check) (source);
4000
4001 TRACE (GLIB_MAIN_AFTER_CHECK (source, check, result));
4002
4003 g_trace_mark (begin_time_nsec, G_TRACE_CURRENT_TIME - begin_time_nsec,
4004 "GLib", "GSource.check",
4005 "%s ⇒ %s",
4006 (g_source_get_name (source) != NULL) ? g_source_get_name (source) : "(unnamed)",
4007 result ? "dispatch" : "ignore");
4008
4009 LOCK_CONTEXT (context);
4010 context->in_check_or_prepare--;
4011 }
4012 else
4013 result = FALSE;
4014
4015 if (result == FALSE)
4016 {
4017 GSList *tmp_list;
4018
4019 /* If not already explicitly flagged ready by ->check()
4020 * (or if we have no check) then we can still be ready if
4021 * any of our fds poll as ready.
4022 */
4023 for (tmp_list = source->priv->fds; tmp_list; tmp_list = tmp_list->next)
4024 {
4025 GPollFD *pollfd = tmp_list->data;
4026
4027 if (pollfd->revents)
4028 {
4029 result = TRUE;
4030 break;
4031 }
4032 }
4033 }
4034
4035 if (result == FALSE && source->priv->ready_time != -1)
4036 {
4037 if (!context->time_is_fresh)
4038 {
4039 context->time = g_get_monotonic_time ();
4040 context->time_is_fresh = TRUE;
4041 }
4042
4043 if (source->priv->ready_time <= context->time)
4044 result = TRUE;
4045 }
4046
4047 if (result)
4048 {
4049 GSource *ready_source = source;
4050
4051 while (ready_source)
4052 {
4053 ready_source->flags |= G_SOURCE_READY;
4054 ready_source = ready_source->priv->parent_source;
4055 }
4056 }
4057 }
4058
4059 if (source->flags & G_SOURCE_READY)
4060 {
4061 g_source_ref (source);
4062 g_ptr_array_add (context->pending_dispatches, source);
4063
4064 n_ready++;
4065
4066 /* never dispatch sources with less priority than the first
4067 * one we choose to dispatch
4068 */
4069 max_priority = source->priority;
4070 }
4071 }
4072 g_source_iter_clear (&iter);
4073
4074 TRACE (GLIB_MAIN_CONTEXT_AFTER_CHECK (context, n_ready));
4075
4076 UNLOCK_CONTEXT (context);
4077
4078 return n_ready > 0;
4079 }
4080
4081 /**
4082 * g_main_context_dispatch:
4083 * @context: a #GMainContext
4084 *
4085 * Dispatches all pending sources.
4086 *
4087 * You must have successfully acquired the context with
4088 * g_main_context_acquire() before you may call this function.
4089 **/
4090 void
g_main_context_dispatch(GMainContext * context)4091 g_main_context_dispatch (GMainContext *context)
4092 {
4093 LOCK_CONTEXT (context);
4094
4095 TRACE (GLIB_MAIN_CONTEXT_BEFORE_DISPATCH (context));
4096
4097 if (context->pending_dispatches->len > 0)
4098 {
4099 g_main_dispatch (context);
4100 }
4101
4102 TRACE (GLIB_MAIN_CONTEXT_AFTER_DISPATCH (context));
4103
4104 UNLOCK_CONTEXT (context);
4105 }
4106
4107 /* HOLDS context lock */
4108 static gboolean
g_main_context_iterate(GMainContext * context,gboolean block,gboolean dispatch,GThread * self)4109 g_main_context_iterate (GMainContext *context,
4110 gboolean block,
4111 gboolean dispatch,
4112 GThread *self)
4113 {
4114 gint max_priority;
4115 gint timeout;
4116 gboolean some_ready;
4117 gint nfds, allocated_nfds;
4118 GPollFD *fds = NULL;
4119 gint64 begin_time_nsec G_GNUC_UNUSED;
4120
4121 UNLOCK_CONTEXT (context);
4122
4123 begin_time_nsec = G_TRACE_CURRENT_TIME;
4124
4125 if (!g_main_context_acquire (context))
4126 {
4127 gboolean got_ownership;
4128
4129 LOCK_CONTEXT (context);
4130
4131 if (!block)
4132 return FALSE;
4133
4134 got_ownership = g_main_context_wait_internal (context,
4135 &context->cond,
4136 &context->mutex);
4137
4138 if (!got_ownership)
4139 return FALSE;
4140 }
4141 else
4142 LOCK_CONTEXT (context);
4143
4144 if (!context->cached_poll_array)
4145 {
4146 context->cached_poll_array_size = context->n_poll_records;
4147 context->cached_poll_array = g_new (GPollFD, context->n_poll_records);
4148 }
4149
4150 allocated_nfds = context->cached_poll_array_size;
4151 fds = context->cached_poll_array;
4152
4153 UNLOCK_CONTEXT (context);
4154
4155 g_main_context_prepare (context, &max_priority);
4156
4157 while ((nfds = g_main_context_query (context, max_priority, &timeout, fds,
4158 allocated_nfds)) > allocated_nfds)
4159 {
4160 LOCK_CONTEXT (context);
4161 g_free (fds);
4162 context->cached_poll_array_size = allocated_nfds = nfds;
4163 context->cached_poll_array = fds = g_new (GPollFD, nfds);
4164 UNLOCK_CONTEXT (context);
4165 }
4166
4167 if (!block)
4168 timeout = 0;
4169
4170 g_main_context_poll (context, timeout, max_priority, fds, nfds);
4171
4172 some_ready = g_main_context_check (context, max_priority, fds, nfds);
4173
4174 if (dispatch)
4175 g_main_context_dispatch (context);
4176
4177 g_main_context_release (context);
4178
4179 g_trace_mark (begin_time_nsec, G_TRACE_CURRENT_TIME - begin_time_nsec,
4180 "GLib", "g_main_context_iterate",
4181 "Context %p, %s ⇒ %s", context, block ? "blocking" : "non-blocking", some_ready ? "dispatched" : "nothing");
4182
4183 LOCK_CONTEXT (context);
4184
4185 return some_ready;
4186 }
4187
4188 /**
4189 * g_main_context_pending:
4190 * @context: (nullable): a #GMainContext (if %NULL, the default context will be used)
4191 *
4192 * Checks if any sources have pending events for the given context.
4193 *
4194 * Returns: %TRUE if events are pending.
4195 **/
4196 gboolean
g_main_context_pending(GMainContext * context)4197 g_main_context_pending (GMainContext *context)
4198 {
4199 gboolean retval;
4200
4201 if (!context)
4202 context = g_main_context_default();
4203
4204 LOCK_CONTEXT (context);
4205 retval = g_main_context_iterate (context, FALSE, FALSE, G_THREAD_SELF);
4206 UNLOCK_CONTEXT (context);
4207
4208 return retval;
4209 }
4210
4211 /**
4212 * g_main_context_iteration:
4213 * @context: (nullable): a #GMainContext (if %NULL, the default context will be used)
4214 * @may_block: whether the call may block.
4215 *
4216 * Runs a single iteration for the given main loop. This involves
4217 * checking to see if any event sources are ready to be processed,
4218 * then if no events sources are ready and @may_block is %TRUE, waiting
4219 * for a source to become ready, then dispatching the highest priority
4220 * events sources that are ready. Otherwise, if @may_block is %FALSE
4221 * sources are not waited to become ready, only those highest priority
4222 * events sources will be dispatched (if any), that are ready at this
4223 * given moment without further waiting.
4224 *
4225 * Note that even when @may_block is %TRUE, it is still possible for
4226 * g_main_context_iteration() to return %FALSE, since the wait may
4227 * be interrupted for other reasons than an event source becoming ready.
4228 *
4229 * Returns: %TRUE if events were dispatched.
4230 **/
4231 gboolean
g_main_context_iteration(GMainContext * context,gboolean may_block)4232 g_main_context_iteration (GMainContext *context, gboolean may_block)
4233 {
4234 gboolean retval;
4235
4236 if (!context)
4237 context = g_main_context_default();
4238
4239 LOCK_CONTEXT (context);
4240 retval = g_main_context_iterate (context, may_block, TRUE, G_THREAD_SELF);
4241 UNLOCK_CONTEXT (context);
4242
4243 return retval;
4244 }
4245
4246 /**
4247 * g_main_loop_new:
4248 * @context: (nullable): a #GMainContext (if %NULL, the default context will be used).
4249 * @is_running: set to %TRUE to indicate that the loop is running. This
4250 * is not very important since calling g_main_loop_run() will set this to
4251 * %TRUE anyway.
4252 *
4253 * Creates a new #GMainLoop structure.
4254 *
4255 * Returns: a new #GMainLoop.
4256 **/
4257 GMainLoop *
g_main_loop_new(GMainContext * context,gboolean is_running)4258 g_main_loop_new (GMainContext *context,
4259 gboolean is_running)
4260 {
4261 GMainLoop *loop;
4262
4263 if (!context)
4264 context = g_main_context_default();
4265
4266 g_main_context_ref (context);
4267
4268 loop = g_new0 (GMainLoop, 1);
4269 loop->context = context;
4270 loop->is_running = is_running != FALSE;
4271 loop->ref_count = 1;
4272
4273 TRACE (GLIB_MAIN_LOOP_NEW (loop, context));
4274
4275 return loop;
4276 }
4277
4278 /**
4279 * g_main_loop_ref:
4280 * @loop: a #GMainLoop
4281 *
4282 * Increases the reference count on a #GMainLoop object by one.
4283 *
4284 * Returns: @loop
4285 **/
4286 GMainLoop *
g_main_loop_ref(GMainLoop * loop)4287 g_main_loop_ref (GMainLoop *loop)
4288 {
4289 g_return_val_if_fail (loop != NULL, NULL);
4290 g_return_val_if_fail (g_atomic_int_get (&loop->ref_count) > 0, NULL);
4291
4292 g_atomic_int_inc (&loop->ref_count);
4293
4294 return loop;
4295 }
4296
4297 /**
4298 * g_main_loop_unref:
4299 * @loop: a #GMainLoop
4300 *
4301 * Decreases the reference count on a #GMainLoop object by one. If
4302 * the result is zero, free the loop and free all associated memory.
4303 **/
4304 void
g_main_loop_unref(GMainLoop * loop)4305 g_main_loop_unref (GMainLoop *loop)
4306 {
4307 g_return_if_fail (loop != NULL);
4308 g_return_if_fail (g_atomic_int_get (&loop->ref_count) > 0);
4309
4310 if (!g_atomic_int_dec_and_test (&loop->ref_count))
4311 return;
4312
4313 g_main_context_unref (loop->context);
4314 g_free (loop);
4315 }
4316
4317 /**
4318 * g_main_loop_run:
4319 * @loop: a #GMainLoop
4320 *
4321 * Runs a main loop until g_main_loop_quit() is called on the loop.
4322 * If this is called for the thread of the loop's #GMainContext,
4323 * it will process events from the loop, otherwise it will
4324 * simply wait.
4325 **/
4326 void
g_main_loop_run(GMainLoop * loop)4327 g_main_loop_run (GMainLoop *loop)
4328 {
4329 GThread *self = G_THREAD_SELF;
4330
4331 g_return_if_fail (loop != NULL);
4332 g_return_if_fail (g_atomic_int_get (&loop->ref_count) > 0);
4333
4334 if (!g_main_context_acquire (loop->context))
4335 {
4336 gboolean got_ownership = FALSE;
4337
4338 /* Another thread owns this context */
4339 LOCK_CONTEXT (loop->context);
4340
4341 g_atomic_int_inc (&loop->ref_count);
4342 g_atomic_int_set (&loop->is_running, TRUE);
4343
4344 while (g_atomic_int_get (&loop->is_running) && !got_ownership)
4345 got_ownership = g_main_context_wait_internal (loop->context,
4346 &loop->context->cond,
4347 &loop->context->mutex);
4348
4349 if (!g_atomic_int_get (&loop->is_running))
4350 {
4351 UNLOCK_CONTEXT (loop->context);
4352 if (got_ownership)
4353 g_main_context_release (loop->context);
4354 g_main_loop_unref (loop);
4355 return;
4356 }
4357
4358 g_assert (got_ownership);
4359 }
4360 else
4361 LOCK_CONTEXT (loop->context);
4362
4363 if (loop->context->in_check_or_prepare)
4364 {
4365 g_warning ("g_main_loop_run(): called recursively from within a source's "
4366 "check() or prepare() member, iteration not possible.");
4367 return;
4368 }
4369
4370 g_atomic_int_inc (&loop->ref_count);
4371 g_atomic_int_set (&loop->is_running, TRUE);
4372 while (g_atomic_int_get (&loop->is_running))
4373 g_main_context_iterate (loop->context, TRUE, TRUE, self);
4374
4375 UNLOCK_CONTEXT (loop->context);
4376
4377 g_main_context_release (loop->context);
4378
4379 g_main_loop_unref (loop);
4380 }
4381
4382 /**
4383 * g_main_loop_quit:
4384 * @loop: a #GMainLoop
4385 *
4386 * Stops a #GMainLoop from running. Any calls to g_main_loop_run()
4387 * for the loop will return.
4388 *
4389 * Note that sources that have already been dispatched when
4390 * g_main_loop_quit() is called will still be executed.
4391 **/
4392 void
g_main_loop_quit(GMainLoop * loop)4393 g_main_loop_quit (GMainLoop *loop)
4394 {
4395 g_return_if_fail (loop != NULL);
4396 g_return_if_fail (g_atomic_int_get (&loop->ref_count) > 0);
4397
4398 LOCK_CONTEXT (loop->context);
4399 g_atomic_int_set (&loop->is_running, FALSE);
4400 g_wakeup_signal (loop->context->wakeup);
4401
4402 g_cond_broadcast (&loop->context->cond);
4403
4404 UNLOCK_CONTEXT (loop->context);
4405
4406 TRACE (GLIB_MAIN_LOOP_QUIT (loop));
4407 }
4408
4409 /**
4410 * g_main_loop_is_running:
4411 * @loop: a #GMainLoop.
4412 *
4413 * Checks to see if the main loop is currently being run via g_main_loop_run().
4414 *
4415 * Returns: %TRUE if the mainloop is currently being run.
4416 **/
4417 gboolean
g_main_loop_is_running(GMainLoop * loop)4418 g_main_loop_is_running (GMainLoop *loop)
4419 {
4420 g_return_val_if_fail (loop != NULL, FALSE);
4421 g_return_val_if_fail (g_atomic_int_get (&loop->ref_count) > 0, FALSE);
4422
4423 return g_atomic_int_get (&loop->is_running);
4424 }
4425
4426 /**
4427 * g_main_loop_get_context:
4428 * @loop: a #GMainLoop.
4429 *
4430 * Returns the #GMainContext of @loop.
4431 *
4432 * Returns: (transfer none): the #GMainContext of @loop
4433 **/
4434 GMainContext *
g_main_loop_get_context(GMainLoop * loop)4435 g_main_loop_get_context (GMainLoop *loop)
4436 {
4437 g_return_val_if_fail (loop != NULL, NULL);
4438 g_return_val_if_fail (g_atomic_int_get (&loop->ref_count) > 0, NULL);
4439
4440 return loop->context;
4441 }
4442
4443 /* HOLDS: context's lock */
4444 static void
g_main_context_poll(GMainContext * context,gint timeout,gint priority,GPollFD * fds,gint n_fds)4445 g_main_context_poll (GMainContext *context,
4446 gint timeout,
4447 gint priority,
4448 GPollFD *fds,
4449 gint n_fds)
4450 {
4451 #ifdef G_MAIN_POLL_DEBUG
4452 GTimer *poll_timer;
4453 GPollRec *pollrec;
4454 gint i;
4455 #endif
4456
4457 GPollFunc poll_func;
4458
4459 if (n_fds || timeout != 0)
4460 {
4461 int ret, errsv;
4462
4463 #ifdef G_MAIN_POLL_DEBUG
4464 poll_timer = NULL;
4465 if (_g_main_poll_debug)
4466 {
4467 g_print ("polling context=%p n=%d timeout=%d\n",
4468 context, n_fds, timeout);
4469 poll_timer = g_timer_new ();
4470 }
4471 #endif
4472
4473 LOCK_CONTEXT (context);
4474
4475 poll_func = context->poll_func;
4476
4477 UNLOCK_CONTEXT (context);
4478 ret = (*poll_func) (fds, n_fds, timeout);
4479 errsv = errno;
4480 if (ret < 0 && errsv != EINTR)
4481 {
4482 #ifndef G_OS_WIN32
4483 g_warning ("poll(2) failed due to: %s.",
4484 g_strerror (errsv));
4485 #else
4486 /* If g_poll () returns -1, it has already called g_warning() */
4487 #endif
4488 }
4489
4490 #ifdef G_MAIN_POLL_DEBUG
4491 if (_g_main_poll_debug)
4492 {
4493 LOCK_CONTEXT (context);
4494
4495 g_print ("g_main_poll(%d) timeout: %d - elapsed %12.10f seconds",
4496 n_fds,
4497 timeout,
4498 g_timer_elapsed (poll_timer, NULL));
4499 g_timer_destroy (poll_timer);
4500 pollrec = context->poll_records;
4501
4502 while (pollrec != NULL)
4503 {
4504 i = 0;
4505 while (i < n_fds)
4506 {
4507 if (fds[i].fd == pollrec->fd->fd &&
4508 pollrec->fd->events &&
4509 fds[i].revents)
4510 {
4511 g_print (" [" G_POLLFD_FORMAT " :", fds[i].fd);
4512 if (fds[i].revents & G_IO_IN)
4513 g_print ("i");
4514 if (fds[i].revents & G_IO_OUT)
4515 g_print ("o");
4516 if (fds[i].revents & G_IO_PRI)
4517 g_print ("p");
4518 if (fds[i].revents & G_IO_ERR)
4519 g_print ("e");
4520 if (fds[i].revents & G_IO_HUP)
4521 g_print ("h");
4522 if (fds[i].revents & G_IO_NVAL)
4523 g_print ("n");
4524 g_print ("]");
4525 }
4526 i++;
4527 }
4528 pollrec = pollrec->next;
4529 }
4530 g_print ("\n");
4531
4532 UNLOCK_CONTEXT (context);
4533 }
4534 #endif
4535 } /* if (n_fds || timeout != 0) */
4536 }
4537
4538 /**
4539 * g_main_context_add_poll:
4540 * @context: (nullable): a #GMainContext (or %NULL for the default context)
4541 * @fd: a #GPollFD structure holding information about a file
4542 * descriptor to watch.
4543 * @priority: the priority for this file descriptor which should be
4544 * the same as the priority used for g_source_attach() to ensure that the
4545 * file descriptor is polled whenever the results may be needed.
4546 *
4547 * Adds a file descriptor to the set of file descriptors polled for
4548 * this context. This will very seldom be used directly. Instead
4549 * a typical event source will use g_source_add_unix_fd() instead.
4550 **/
4551 void
g_main_context_add_poll(GMainContext * context,GPollFD * fd,gint priority)4552 g_main_context_add_poll (GMainContext *context,
4553 GPollFD *fd,
4554 gint priority)
4555 {
4556 if (!context)
4557 context = g_main_context_default ();
4558
4559 g_return_if_fail (g_atomic_int_get (&context->ref_count) > 0);
4560 g_return_if_fail (fd);
4561
4562 LOCK_CONTEXT (context);
4563 g_main_context_add_poll_unlocked (context, priority, fd);
4564 UNLOCK_CONTEXT (context);
4565 }
4566
4567 /* HOLDS: main_loop_lock */
4568 static void
g_main_context_add_poll_unlocked(GMainContext * context,gint priority,GPollFD * fd)4569 g_main_context_add_poll_unlocked (GMainContext *context,
4570 gint priority,
4571 GPollFD *fd)
4572 {
4573 GPollRec *prevrec, *nextrec;
4574 GPollRec *newrec = g_slice_new (GPollRec);
4575
4576 /* This file descriptor may be checked before we ever poll */
4577 fd->revents = 0;
4578 newrec->fd = fd;
4579 newrec->priority = priority;
4580
4581 /* Poll records are incrementally sorted by file descriptor identifier. */
4582 prevrec = NULL;
4583 nextrec = context->poll_records;
4584 while (nextrec)
4585 {
4586 if (nextrec->fd->fd > fd->fd)
4587 break;
4588 prevrec = nextrec;
4589 nextrec = nextrec->next;
4590 }
4591
4592 if (prevrec)
4593 prevrec->next = newrec;
4594 else
4595 context->poll_records = newrec;
4596
4597 newrec->prev = prevrec;
4598 newrec->next = nextrec;
4599
4600 if (nextrec)
4601 nextrec->prev = newrec;
4602
4603 context->n_poll_records++;
4604
4605 context->poll_changed = TRUE;
4606
4607 /* Now wake up the main loop if it is waiting in the poll() */
4608 g_wakeup_signal (context->wakeup);
4609 }
4610
4611 /**
4612 * g_main_context_remove_poll:
4613 * @context:a #GMainContext
4614 * @fd: a #GPollFD descriptor previously added with g_main_context_add_poll()
4615 *
4616 * Removes file descriptor from the set of file descriptors to be
4617 * polled for a particular context.
4618 **/
4619 void
g_main_context_remove_poll(GMainContext * context,GPollFD * fd)4620 g_main_context_remove_poll (GMainContext *context,
4621 GPollFD *fd)
4622 {
4623 if (!context)
4624 context = g_main_context_default ();
4625
4626 g_return_if_fail (g_atomic_int_get (&context->ref_count) > 0);
4627 g_return_if_fail (fd);
4628
4629 LOCK_CONTEXT (context);
4630 g_main_context_remove_poll_unlocked (context, fd);
4631 UNLOCK_CONTEXT (context);
4632 }
4633
4634 static void
g_main_context_remove_poll_unlocked(GMainContext * context,GPollFD * fd)4635 g_main_context_remove_poll_unlocked (GMainContext *context,
4636 GPollFD *fd)
4637 {
4638 GPollRec *pollrec, *prevrec, *nextrec;
4639
4640 prevrec = NULL;
4641 pollrec = context->poll_records;
4642
4643 while (pollrec)
4644 {
4645 nextrec = pollrec->next;
4646 if (pollrec->fd == fd)
4647 {
4648 if (prevrec != NULL)
4649 prevrec->next = nextrec;
4650 else
4651 context->poll_records = nextrec;
4652
4653 if (nextrec != NULL)
4654 nextrec->prev = prevrec;
4655
4656 g_slice_free (GPollRec, pollrec);
4657
4658 context->n_poll_records--;
4659 break;
4660 }
4661 prevrec = pollrec;
4662 pollrec = nextrec;
4663 }
4664
4665 context->poll_changed = TRUE;
4666
4667 /* Now wake up the main loop if it is waiting in the poll() */
4668 g_wakeup_signal (context->wakeup);
4669 }
4670
4671 /**
4672 * g_source_get_current_time:
4673 * @source: a #GSource
4674 * @timeval: #GTimeVal structure in which to store current time.
4675 *
4676 * This function ignores @source and is otherwise the same as
4677 * g_get_current_time().
4678 *
4679 * Deprecated: 2.28: use g_source_get_time() instead
4680 **/
4681 G_GNUC_BEGIN_IGNORE_DEPRECATIONS
4682 void
g_source_get_current_time(GSource * source,GTimeVal * timeval)4683 g_source_get_current_time (GSource *source,
4684 GTimeVal *timeval)
4685 {
4686 g_get_current_time (timeval);
4687 }
4688 G_GNUC_END_IGNORE_DEPRECATIONS
4689
4690 /**
4691 * g_source_get_time:
4692 * @source: a #GSource
4693 *
4694 * Gets the time to be used when checking this source. The advantage of
4695 * calling this function over calling g_get_monotonic_time() directly is
4696 * that when checking multiple sources, GLib can cache a single value
4697 * instead of having to repeatedly get the system monotonic time.
4698 *
4699 * The time here is the system monotonic time, if available, or some
4700 * other reasonable alternative otherwise. See g_get_monotonic_time().
4701 *
4702 * Returns: the monotonic time in microseconds
4703 *
4704 * Since: 2.28
4705 **/
4706 gint64
g_source_get_time(GSource * source)4707 g_source_get_time (GSource *source)
4708 {
4709 GMainContext *context;
4710 gint64 result;
4711
4712 g_return_val_if_fail (source != NULL, 0);
4713 g_return_val_if_fail (g_atomic_int_get (&source->ref_count) > 0, 0);
4714 g_return_val_if_fail (source->context != NULL, 0);
4715
4716 context = source->context;
4717
4718 LOCK_CONTEXT (context);
4719
4720 if (!context->time_is_fresh)
4721 {
4722 context->time = g_get_monotonic_time ();
4723 context->time_is_fresh = TRUE;
4724 }
4725
4726 result = context->time;
4727
4728 UNLOCK_CONTEXT (context);
4729
4730 return result;
4731 }
4732
4733 /**
4734 * g_main_context_set_poll_func:
4735 * @context: a #GMainContext
4736 * @func: the function to call to poll all file descriptors
4737 *
4738 * Sets the function to use to handle polling of file descriptors. It
4739 * will be used instead of the poll() system call
4740 * (or GLib's replacement function, which is used where
4741 * poll() isn't available).
4742 *
4743 * This function could possibly be used to integrate the GLib event
4744 * loop with an external event loop.
4745 **/
4746 void
g_main_context_set_poll_func(GMainContext * context,GPollFunc func)4747 g_main_context_set_poll_func (GMainContext *context,
4748 GPollFunc func)
4749 {
4750 if (!context)
4751 context = g_main_context_default ();
4752
4753 g_return_if_fail (g_atomic_int_get (&context->ref_count) > 0);
4754
4755 LOCK_CONTEXT (context);
4756
4757 if (func)
4758 context->poll_func = func;
4759 else
4760 context->poll_func = g_poll;
4761
4762 UNLOCK_CONTEXT (context);
4763 }
4764
4765 /**
4766 * g_main_context_get_poll_func:
4767 * @context: a #GMainContext
4768 *
4769 * Gets the poll function set by g_main_context_set_poll_func().
4770 *
4771 * Returns: the poll function
4772 **/
4773 GPollFunc
g_main_context_get_poll_func(GMainContext * context)4774 g_main_context_get_poll_func (GMainContext *context)
4775 {
4776 GPollFunc result;
4777
4778 if (!context)
4779 context = g_main_context_default ();
4780
4781 g_return_val_if_fail (g_atomic_int_get (&context->ref_count) > 0, NULL);
4782
4783 LOCK_CONTEXT (context);
4784 result = context->poll_func;
4785 UNLOCK_CONTEXT (context);
4786
4787 return result;
4788 }
4789
4790 /**
4791 * g_main_context_wakeup:
4792 * @context: a #GMainContext
4793 *
4794 * If @context is currently blocking in g_main_context_iteration()
4795 * waiting for a source to become ready, cause it to stop blocking
4796 * and return. Otherwise, cause the next invocation of
4797 * g_main_context_iteration() to return without blocking.
4798 *
4799 * This API is useful for low-level control over #GMainContext; for
4800 * example, integrating it with main loop implementations such as
4801 * #GMainLoop.
4802 *
4803 * Another related use for this function is when implementing a main
4804 * loop with a termination condition, computed from multiple threads:
4805 *
4806 * |[<!-- language="C" -->
4807 * #define NUM_TASKS 10
4808 * static gint tasks_remaining = NUM_TASKS; // (atomic)
4809 * ...
4810 *
4811 * while (g_atomic_int_get (&tasks_remaining) != 0)
4812 * g_main_context_iteration (NULL, TRUE);
4813 * ]|
4814 *
4815 * Then in a thread:
4816 * |[<!-- language="C" -->
4817 * perform_work();
4818 *
4819 * if (g_atomic_int_dec_and_test (&tasks_remaining))
4820 * g_main_context_wakeup (NULL);
4821 * ]|
4822 **/
4823 void
g_main_context_wakeup(GMainContext * context)4824 g_main_context_wakeup (GMainContext *context)
4825 {
4826 if (!context)
4827 context = g_main_context_default ();
4828
4829 g_return_if_fail (g_atomic_int_get (&context->ref_count) > 0);
4830
4831 TRACE (GLIB_MAIN_CONTEXT_WAKEUP (context));
4832
4833 g_wakeup_signal (context->wakeup);
4834 }
4835
4836 /**
4837 * g_main_context_is_owner:
4838 * @context: a #GMainContext
4839 *
4840 * Determines whether this thread holds the (recursive)
4841 * ownership of this #GMainContext. This is useful to
4842 * know before waiting on another thread that may be
4843 * blocking to get ownership of @context.
4844 *
4845 * Returns: %TRUE if current thread is owner of @context.
4846 *
4847 * Since: 2.10
4848 **/
4849 gboolean
g_main_context_is_owner(GMainContext * context)4850 g_main_context_is_owner (GMainContext *context)
4851 {
4852 gboolean is_owner;
4853
4854 if (!context)
4855 context = g_main_context_default ();
4856
4857 LOCK_CONTEXT (context);
4858 is_owner = context->owner == G_THREAD_SELF;
4859 UNLOCK_CONTEXT (context);
4860
4861 return is_owner;
4862 }
4863
4864 /* Timeouts */
4865
4866 static void
g_timeout_set_expiration(GTimeoutSource * timeout_source,gint64 current_time)4867 g_timeout_set_expiration (GTimeoutSource *timeout_source,
4868 gint64 current_time)
4869 {
4870 gint64 expiration;
4871
4872 if (timeout_source->seconds)
4873 {
4874 gint64 remainder;
4875 static gint timer_perturb = -1;
4876
4877 if (timer_perturb == -1)
4878 {
4879 /*
4880 * we want a per machine/session unique 'random' value; try the dbus
4881 * address first, that has a UUID in it. If there is no dbus, use the
4882 * hostname for hashing.
4883 */
4884 const char *session_bus_address = g_getenv ("DBUS_SESSION_BUS_ADDRESS");
4885 if (!session_bus_address)
4886 session_bus_address = g_getenv ("HOSTNAME");
4887 if (session_bus_address)
4888 timer_perturb = ABS ((gint) g_str_hash (session_bus_address)) % 1000000;
4889 else
4890 timer_perturb = 0;
4891 }
4892
4893 expiration = current_time + (guint64) timeout_source->interval * 1000 * 1000;
4894
4895 /* We want the microseconds part of the timeout to land on the
4896 * 'timer_perturb' mark, but we need to make sure we don't try to
4897 * set the timeout in the past. We do this by ensuring that we
4898 * always only *increase* the expiration time by adding a full
4899 * second in the case that the microsecond portion decreases.
4900 */
4901 expiration -= timer_perturb;
4902
4903 remainder = expiration % 1000000;
4904 if (remainder >= 1000000/4)
4905 expiration += 1000000;
4906
4907 expiration -= remainder;
4908 expiration += timer_perturb;
4909 }
4910 else
4911 {
4912 expiration = current_time + (guint64) timeout_source->interval * 1000;
4913 }
4914
4915 g_source_set_ready_time ((GSource *) timeout_source, expiration);
4916 }
4917
4918 static gboolean
g_timeout_dispatch(GSource * source,GSourceFunc callback,gpointer user_data)4919 g_timeout_dispatch (GSource *source,
4920 GSourceFunc callback,
4921 gpointer user_data)
4922 {
4923 GTimeoutSource *timeout_source = (GTimeoutSource *)source;
4924 gboolean again;
4925
4926 if (!callback)
4927 {
4928 g_warning ("Timeout source dispatched without callback. "
4929 "You must call g_source_set_callback().");
4930 return FALSE;
4931 }
4932
4933 again = callback (user_data);
4934
4935 TRACE (GLIB_TIMEOUT_DISPATCH (source, source->context, callback, user_data, again));
4936
4937 if (again)
4938 g_timeout_set_expiration (timeout_source, g_source_get_time (source));
4939
4940 return again;
4941 }
4942
4943 /**
4944 * g_timeout_source_new:
4945 * @interval: the timeout interval in milliseconds.
4946 *
4947 * Creates a new timeout source.
4948 *
4949 * The source will not initially be associated with any #GMainContext
4950 * and must be added to one with g_source_attach() before it will be
4951 * executed.
4952 *
4953 * The interval given is in terms of monotonic time, not wall clock
4954 * time. See g_get_monotonic_time().
4955 *
4956 * Returns: the newly-created timeout source
4957 **/
4958 GSource *
g_timeout_source_new(guint interval)4959 g_timeout_source_new (guint interval)
4960 {
4961 GSource *source = g_source_new (&g_timeout_funcs, sizeof (GTimeoutSource));
4962 GTimeoutSource *timeout_source = (GTimeoutSource *)source;
4963
4964 timeout_source->interval = interval;
4965 g_timeout_set_expiration (timeout_source, g_get_monotonic_time ());
4966
4967 return source;
4968 }
4969
4970 /**
4971 * g_timeout_source_new_seconds:
4972 * @interval: the timeout interval in seconds
4973 *
4974 * Creates a new timeout source.
4975 *
4976 * The source will not initially be associated with any #GMainContext
4977 * and must be added to one with g_source_attach() before it will be
4978 * executed.
4979 *
4980 * The scheduling granularity/accuracy of this timeout source will be
4981 * in seconds.
4982 *
4983 * The interval given is in terms of monotonic time, not wall clock time.
4984 * See g_get_monotonic_time().
4985 *
4986 * Returns: the newly-created timeout source
4987 *
4988 * Since: 2.14
4989 **/
4990 GSource *
g_timeout_source_new_seconds(guint interval)4991 g_timeout_source_new_seconds (guint interval)
4992 {
4993 GSource *source = g_source_new (&g_timeout_funcs, sizeof (GTimeoutSource));
4994 GTimeoutSource *timeout_source = (GTimeoutSource *)source;
4995
4996 timeout_source->interval = interval;
4997 timeout_source->seconds = TRUE;
4998
4999 g_timeout_set_expiration (timeout_source, g_get_monotonic_time ());
5000
5001 return source;
5002 }
5003
5004
5005 /**
5006 * g_timeout_add_full: (rename-to g_timeout_add)
5007 * @priority: the priority of the timeout source. Typically this will be in
5008 * the range between %G_PRIORITY_DEFAULT and %G_PRIORITY_HIGH.
5009 * @interval: the time between calls to the function, in milliseconds
5010 * (1/1000ths of a second)
5011 * @function: function to call
5012 * @data: data to pass to @function
5013 * @notify: (nullable): function to call when the timeout is removed, or %NULL
5014 *
5015 * Sets a function to be called at regular intervals, with the given
5016 * priority. The function is called repeatedly until it returns
5017 * %FALSE, at which point the timeout is automatically destroyed and
5018 * the function will not be called again. The @notify function is
5019 * called when the timeout is destroyed. The first call to the
5020 * function will be at the end of the first @interval.
5021 *
5022 * Note that timeout functions may be delayed, due to the processing of other
5023 * event sources. Thus they should not be relied on for precise timing.
5024 * After each call to the timeout function, the time of the next
5025 * timeout is recalculated based on the current time and the given interval
5026 * (it does not try to 'catch up' time lost in delays).
5027 *
5028 * See [memory management of sources][mainloop-memory-management] for details
5029 * on how to handle the return value and memory management of @data.
5030 *
5031 * This internally creates a main loop source using g_timeout_source_new()
5032 * and attaches it to the global #GMainContext using g_source_attach(), so
5033 * the callback will be invoked in whichever thread is running that main
5034 * context. You can do these steps manually if you need greater control or to
5035 * use a custom main context.
5036 *
5037 * The interval given is in terms of monotonic time, not wall clock time.
5038 * See g_get_monotonic_time().
5039 *
5040 * Returns: the ID (greater than 0) of the event source.
5041 **/
5042 guint
g_timeout_add_full(gint priority,guint interval,GSourceFunc function,gpointer data,GDestroyNotify notify)5043 g_timeout_add_full (gint priority,
5044 guint interval,
5045 GSourceFunc function,
5046 gpointer data,
5047 GDestroyNotify notify)
5048 {
5049 GSource *source;
5050 guint id;
5051
5052 g_return_val_if_fail (function != NULL, 0);
5053
5054 source = g_timeout_source_new (interval);
5055
5056 if (priority != G_PRIORITY_DEFAULT)
5057 g_source_set_priority (source, priority);
5058
5059 g_source_set_callback (source, function, data, notify);
5060 id = g_source_attach (source, NULL);
5061
5062 TRACE (GLIB_TIMEOUT_ADD (source, g_main_context_default (), id, priority, interval, function, data));
5063
5064 g_source_unref (source);
5065
5066 return id;
5067 }
5068
5069 /**
5070 * g_timeout_add:
5071 * @interval: the time between calls to the function, in milliseconds
5072 * (1/1000ths of a second)
5073 * @function: function to call
5074 * @data: data to pass to @function
5075 *
5076 * Sets a function to be called at regular intervals, with the default
5077 * priority, %G_PRIORITY_DEFAULT.
5078 *
5079 * The given @function is called repeatedly until it returns %G_SOURCE_REMOVE
5080 * or %FALSE, at which point the timeout is automatically destroyed and the
5081 * function will not be called again. The first call to the function will be
5082 * at the end of the first @interval.
5083 *
5084 * Note that timeout functions may be delayed, due to the processing of other
5085 * event sources. Thus they should not be relied on for precise timing.
5086 * After each call to the timeout function, the time of the next
5087 * timeout is recalculated based on the current time and the given interval
5088 * (it does not try to 'catch up' time lost in delays).
5089 *
5090 * See [memory management of sources][mainloop-memory-management] for details
5091 * on how to handle the return value and memory management of @data.
5092 *
5093 * If you want to have a timer in the "seconds" range and do not care
5094 * about the exact time of the first call of the timer, use the
5095 * g_timeout_add_seconds() function; this function allows for more
5096 * optimizations and more efficient system power usage.
5097 *
5098 * This internally creates a main loop source using g_timeout_source_new()
5099 * and attaches it to the global #GMainContext using g_source_attach(), so
5100 * the callback will be invoked in whichever thread is running that main
5101 * context. You can do these steps manually if you need greater control or to
5102 * use a custom main context.
5103 *
5104 * It is safe to call this function from any thread.
5105 *
5106 * The interval given is in terms of monotonic time, not wall clock
5107 * time. See g_get_monotonic_time().
5108 *
5109 * Returns: the ID (greater than 0) of the event source.
5110 **/
5111 guint
g_timeout_add(guint32 interval,GSourceFunc function,gpointer data)5112 g_timeout_add (guint32 interval,
5113 GSourceFunc function,
5114 gpointer data)
5115 {
5116 return g_timeout_add_full (G_PRIORITY_DEFAULT,
5117 interval, function, data, NULL);
5118 }
5119
5120 /**
5121 * g_timeout_add_seconds_full: (rename-to g_timeout_add_seconds)
5122 * @priority: the priority of the timeout source. Typically this will be in
5123 * the range between %G_PRIORITY_DEFAULT and %G_PRIORITY_HIGH.
5124 * @interval: the time between calls to the function, in seconds
5125 * @function: function to call
5126 * @data: data to pass to @function
5127 * @notify: (nullable): function to call when the timeout is removed, or %NULL
5128 *
5129 * Sets a function to be called at regular intervals, with @priority.
5130 *
5131 * The function is called repeatedly until it returns %G_SOURCE_REMOVE
5132 * or %FALSE, at which point the timeout is automatically destroyed and
5133 * the function will not be called again.
5134 *
5135 * Unlike g_timeout_add(), this function operates at whole second granularity.
5136 * The initial starting point of the timer is determined by the implementation
5137 * and the implementation is expected to group multiple timers together so that
5138 * they fire all at the same time. To allow this grouping, the @interval to the
5139 * first timer is rounded and can deviate up to one second from the specified
5140 * interval. Subsequent timer iterations will generally run at the specified
5141 * interval.
5142 *
5143 * Note that timeout functions may be delayed, due to the processing of other
5144 * event sources. Thus they should not be relied on for precise timing.
5145 * After each call to the timeout function, the time of the next
5146 * timeout is recalculated based on the current time and the given @interval
5147 *
5148 * See [memory management of sources][mainloop-memory-management] for details
5149 * on how to handle the return value and memory management of @data.
5150 *
5151 * If you want timing more precise than whole seconds, use g_timeout_add()
5152 * instead.
5153 *
5154 * The grouping of timers to fire at the same time results in a more power
5155 * and CPU efficient behavior so if your timer is in multiples of seconds
5156 * and you don't require the first timer exactly one second from now, the
5157 * use of g_timeout_add_seconds() is preferred over g_timeout_add().
5158 *
5159 * This internally creates a main loop source using
5160 * g_timeout_source_new_seconds() and attaches it to the main loop context
5161 * using g_source_attach(). You can do these steps manually if you need
5162 * greater control.
5163 *
5164 * It is safe to call this function from any thread.
5165 *
5166 * The interval given is in terms of monotonic time, not wall clock
5167 * time. See g_get_monotonic_time().
5168 *
5169 * Returns: the ID (greater than 0) of the event source.
5170 *
5171 * Since: 2.14
5172 **/
5173 guint
g_timeout_add_seconds_full(gint priority,guint32 interval,GSourceFunc function,gpointer data,GDestroyNotify notify)5174 g_timeout_add_seconds_full (gint priority,
5175 guint32 interval,
5176 GSourceFunc function,
5177 gpointer data,
5178 GDestroyNotify notify)
5179 {
5180 GSource *source;
5181 guint id;
5182
5183 g_return_val_if_fail (function != NULL, 0);
5184
5185 source = g_timeout_source_new_seconds (interval);
5186
5187 if (priority != G_PRIORITY_DEFAULT)
5188 g_source_set_priority (source, priority);
5189
5190 g_source_set_callback (source, function, data, notify);
5191 id = g_source_attach (source, NULL);
5192 g_source_unref (source);
5193
5194 return id;
5195 }
5196
5197 /**
5198 * g_timeout_add_seconds:
5199 * @interval: the time between calls to the function, in seconds
5200 * @function: function to call
5201 * @data: data to pass to @function
5202 *
5203 * Sets a function to be called at regular intervals with the default
5204 * priority, %G_PRIORITY_DEFAULT.
5205 *
5206 * The function is called repeatedly until it returns %G_SOURCE_REMOVE
5207 * or %FALSE, at which point the timeout is automatically destroyed
5208 * and the function will not be called again.
5209 *
5210 * This internally creates a main loop source using
5211 * g_timeout_source_new_seconds() and attaches it to the main loop context
5212 * using g_source_attach(). You can do these steps manually if you need
5213 * greater control. Also see g_timeout_add_seconds_full().
5214 *
5215 * It is safe to call this function from any thread.
5216 *
5217 * Note that the first call of the timer may not be precise for timeouts
5218 * of one second. If you need finer precision and have such a timeout,
5219 * you may want to use g_timeout_add() instead.
5220 *
5221 * See [memory management of sources][mainloop-memory-management] for details
5222 * on how to handle the return value and memory management of @data.
5223 *
5224 * The interval given is in terms of monotonic time, not wall clock
5225 * time. See g_get_monotonic_time().
5226 *
5227 * Returns: the ID (greater than 0) of the event source.
5228 *
5229 * Since: 2.14
5230 **/
5231 guint
g_timeout_add_seconds(guint interval,GSourceFunc function,gpointer data)5232 g_timeout_add_seconds (guint interval,
5233 GSourceFunc function,
5234 gpointer data)
5235 {
5236 g_return_val_if_fail (function != NULL, 0);
5237
5238 return g_timeout_add_seconds_full (G_PRIORITY_DEFAULT, interval, function, data, NULL);
5239 }
5240
5241 /* Child watch functions */
5242
5243 #ifdef G_OS_WIN32
5244
5245 static gboolean
g_child_watch_prepare(GSource * source,gint * timeout)5246 g_child_watch_prepare (GSource *source,
5247 gint *timeout)
5248 {
5249 *timeout = -1;
5250 return FALSE;
5251 }
5252
5253 static gboolean
g_child_watch_check(GSource * source)5254 g_child_watch_check (GSource *source)
5255 {
5256 GChildWatchSource *child_watch_source;
5257 gboolean child_exited;
5258
5259 child_watch_source = (GChildWatchSource *) source;
5260
5261 child_exited = child_watch_source->poll.revents & G_IO_IN;
5262
5263 if (child_exited)
5264 {
5265 DWORD child_status;
5266
5267 /*
5268 * Note: We do _not_ check for the special value of STILL_ACTIVE
5269 * since we know that the process has exited and doing so runs into
5270 * problems if the child process "happens to return STILL_ACTIVE(259)"
5271 * as Microsoft's Platform SDK puts it.
5272 */
5273 if (!GetExitCodeProcess (child_watch_source->pid, &child_status))
5274 {
5275 gchar *emsg = g_win32_error_message (GetLastError ());
5276 g_warning (G_STRLOC ": GetExitCodeProcess() failed: %s", emsg);
5277 g_free (emsg);
5278
5279 child_watch_source->child_status = -1;
5280 }
5281 else
5282 child_watch_source->child_status = child_status;
5283 }
5284
5285 return child_exited;
5286 }
5287
5288 static void
g_child_watch_finalize(GSource * source)5289 g_child_watch_finalize (GSource *source)
5290 {
5291 }
5292
5293 #else /* G_OS_WIN32 */
5294
5295 static void
wake_source(GSource * source)5296 wake_source (GSource *source)
5297 {
5298 GMainContext *context;
5299
5300 /* This should be thread-safe:
5301 *
5302 * - if the source is currently being added to a context, that
5303 * context will be woken up anyway
5304 *
5305 * - if the source is currently being destroyed, we simply need not
5306 * to crash:
5307 *
5308 * - the memory for the source will remain valid until after the
5309 * source finalize function was called (which would remove the
5310 * source from the global list which we are currently holding the
5311 * lock for)
5312 *
5313 * - the GMainContext will either be NULL or point to a live
5314 * GMainContext
5315 *
5316 * - the GMainContext will remain valid since we hold the
5317 * main_context_list lock
5318 *
5319 * Since we are holding a lot of locks here, don't try to enter any
5320 * more GMainContext functions for fear of dealock -- just hit the
5321 * GWakeup and run. Even if that's safe now, it could easily become
5322 * unsafe with some very minor changes in the future, and signal
5323 * handling is not the most well-tested codepath.
5324 */
5325 G_LOCK(main_context_list);
5326 context = source->context;
5327 if (context)
5328 g_wakeup_signal (context->wakeup);
5329 G_UNLOCK(main_context_list);
5330 }
5331
5332 static void
dispatch_unix_signals_unlocked(void)5333 dispatch_unix_signals_unlocked (void)
5334 {
5335 gboolean pending[NSIG];
5336 GSList *node;
5337 gint i;
5338
5339 /* clear this first in case another one arrives while we're processing */
5340 g_atomic_int_set (&any_unix_signal_pending, 0);
5341
5342 /* We atomically test/clear the bit from the global array in case
5343 * other signals arrive while we are dispatching.
5344 *
5345 * We then can safely use our own array below without worrying about
5346 * races.
5347 */
5348 for (i = 0; i < NSIG; i++)
5349 {
5350 /* Be very careful with (the volatile) unix_signal_pending.
5351 *
5352 * We must ensure that it's not possible that we clear it without
5353 * handling the signal. We therefore must ensure that our pending
5354 * array has a field set (ie: we will do something about the
5355 * signal) before we clear the item in unix_signal_pending.
5356 *
5357 * Note specifically: we must check _our_ array.
5358 */
5359 pending[i] = g_atomic_int_compare_and_exchange (&unix_signal_pending[i], 1, 0);
5360 }
5361
5362 /* handle GChildWatchSource instances */
5363 if (pending[SIGCHLD])
5364 {
5365 /* The only way we can do this is to scan all of the children.
5366 *
5367 * The docs promise that we will not reap children that we are not
5368 * explicitly watching, so that ties our hands from calling
5369 * waitpid(-1). We also can't use siginfo's si_pid field since if
5370 * multiple SIGCHLD arrive at the same time, one of them can be
5371 * dropped (since a given UNIX signal can only be pending once).
5372 */
5373 for (node = unix_child_watches; node; node = node->next)
5374 {
5375 GChildWatchSource *source = node->data;
5376
5377 if (!g_atomic_int_get (&source->child_exited))
5378 {
5379 pid_t pid;
5380 do
5381 {
5382 g_assert (source->pid > 0);
5383
5384 pid = waitpid (source->pid, &source->child_status, WNOHANG);
5385 if (pid > 0)
5386 {
5387 g_atomic_int_set (&source->child_exited, TRUE);
5388 wake_source ((GSource *) source);
5389 }
5390 else if (pid == -1 && errno == ECHILD)
5391 {
5392 g_warning ("GChildWatchSource: Exit status of a child process was requested but ECHILD was received by waitpid(). See the documentation of g_child_watch_source_new() for possible causes.");
5393 source->child_status = 0;
5394 g_atomic_int_set (&source->child_exited, TRUE);
5395 wake_source ((GSource *) source);
5396 }
5397 }
5398 while (pid == -1 && errno == EINTR);
5399 }
5400 }
5401 }
5402
5403 /* handle GUnixSignalWatchSource instances */
5404 for (node = unix_signal_watches; node; node = node->next)
5405 {
5406 GUnixSignalWatchSource *source = node->data;
5407
5408 if (pending[source->signum] &&
5409 g_atomic_int_compare_and_exchange (&source->pending, FALSE, TRUE))
5410 {
5411 wake_source ((GSource *) source);
5412 }
5413 }
5414
5415 }
5416
5417 static void
dispatch_unix_signals(void)5418 dispatch_unix_signals (void)
5419 {
5420 G_LOCK(unix_signal_lock);
5421 dispatch_unix_signals_unlocked ();
5422 G_UNLOCK(unix_signal_lock);
5423 }
5424
5425 static gboolean
g_child_watch_prepare(GSource * source,gint * timeout)5426 g_child_watch_prepare (GSource *source,
5427 gint *timeout)
5428 {
5429 GChildWatchSource *child_watch_source;
5430
5431 child_watch_source = (GChildWatchSource *) source;
5432
5433 return g_atomic_int_get (&child_watch_source->child_exited);
5434 }
5435
5436 static gboolean
g_child_watch_check(GSource * source)5437 g_child_watch_check (GSource *source)
5438 {
5439 GChildWatchSource *child_watch_source;
5440
5441 child_watch_source = (GChildWatchSource *) source;
5442
5443 return g_atomic_int_get (&child_watch_source->child_exited);
5444 }
5445
5446 static gboolean
g_unix_signal_watch_prepare(GSource * source,gint * timeout)5447 g_unix_signal_watch_prepare (GSource *source,
5448 gint *timeout)
5449 {
5450 GUnixSignalWatchSource *unix_signal_source;
5451
5452 unix_signal_source = (GUnixSignalWatchSource *) source;
5453
5454 return g_atomic_int_get (&unix_signal_source->pending);
5455 }
5456
5457 static gboolean
g_unix_signal_watch_check(GSource * source)5458 g_unix_signal_watch_check (GSource *source)
5459 {
5460 GUnixSignalWatchSource *unix_signal_source;
5461
5462 unix_signal_source = (GUnixSignalWatchSource *) source;
5463
5464 return g_atomic_int_get (&unix_signal_source->pending);
5465 }
5466
5467 static gboolean
g_unix_signal_watch_dispatch(GSource * source,GSourceFunc callback,gpointer user_data)5468 g_unix_signal_watch_dispatch (GSource *source,
5469 GSourceFunc callback,
5470 gpointer user_data)
5471 {
5472 GUnixSignalWatchSource *unix_signal_source;
5473 gboolean again;
5474
5475 unix_signal_source = (GUnixSignalWatchSource *) source;
5476
5477 if (!callback)
5478 {
5479 g_warning ("Unix signal source dispatched without callback. "
5480 "You must call g_source_set_callback().");
5481 return FALSE;
5482 }
5483
5484 g_atomic_int_set (&unix_signal_source->pending, FALSE);
5485
5486 again = (callback) (user_data);
5487
5488 return again;
5489 }
5490
5491 static void
ref_unix_signal_handler_unlocked(int signum)5492 ref_unix_signal_handler_unlocked (int signum)
5493 {
5494 /* Ensure we have the worker context */
5495 g_get_worker_context ();
5496 unix_signal_refcount[signum]++;
5497 if (unix_signal_refcount[signum] == 1)
5498 {
5499 struct sigaction action;
5500 action.sa_handler = g_unix_signal_handler;
5501 sigemptyset (&action.sa_mask);
5502 #ifdef SA_RESTART
5503 action.sa_flags = SA_RESTART | SA_NOCLDSTOP;
5504 #else
5505 action.sa_flags = SA_NOCLDSTOP;
5506 #endif
5507 sigaction (signum, &action, NULL);
5508 }
5509 }
5510
5511 static void
unref_unix_signal_handler_unlocked(int signum)5512 unref_unix_signal_handler_unlocked (int signum)
5513 {
5514 unix_signal_refcount[signum]--;
5515 if (unix_signal_refcount[signum] == 0)
5516 {
5517 struct sigaction action;
5518 memset (&action, 0, sizeof (action));
5519 action.sa_handler = SIG_DFL;
5520 sigemptyset (&action.sa_mask);
5521 sigaction (signum, &action, NULL);
5522 }
5523 }
5524
5525 /* Return a const string to avoid allocations. We lose precision in the case the
5526 * @signum is unrecognised, but that’ll do. */
5527 static const gchar *
signum_to_string(int signum)5528 signum_to_string (int signum)
5529 {
5530 /* See `man 0P signal.h` */
5531 #define SIGNAL(s) \
5532 case (s): \
5533 return ("GUnixSignalSource: " #s);
5534 switch (signum)
5535 {
5536 /* These signals are guaranteed to exist by POSIX. */
5537 SIGNAL (SIGABRT)
5538 SIGNAL (SIGFPE)
5539 SIGNAL (SIGILL)
5540 SIGNAL (SIGINT)
5541 SIGNAL (SIGSEGV)
5542 SIGNAL (SIGTERM)
5543 /* Frustratingly, these are not, and hence for brevity the list is
5544 * incomplete. */
5545 #ifdef SIGALRM
5546 SIGNAL (SIGALRM)
5547 #endif
5548 #ifdef SIGCHLD
5549 SIGNAL (SIGCHLD)
5550 #endif
5551 #ifdef SIGHUP
5552 SIGNAL (SIGHUP)
5553 #endif
5554 #ifdef SIGKILL
5555 SIGNAL (SIGKILL)
5556 #endif
5557 #ifdef SIGPIPE
5558 SIGNAL (SIGPIPE)
5559 #endif
5560 #ifdef SIGQUIT
5561 SIGNAL (SIGQUIT)
5562 #endif
5563 #ifdef SIGSTOP
5564 SIGNAL (SIGSTOP)
5565 #endif
5566 #ifdef SIGUSR1
5567 SIGNAL (SIGUSR1)
5568 #endif
5569 #ifdef SIGUSR2
5570 SIGNAL (SIGUSR2)
5571 #endif
5572 #ifdef SIGPOLL
5573 SIGNAL (SIGPOLL)
5574 #endif
5575 #ifdef SIGPROF
5576 SIGNAL (SIGPROF)
5577 #endif
5578 #ifdef SIGTRAP
5579 SIGNAL (SIGTRAP)
5580 #endif
5581 default:
5582 return "GUnixSignalSource: Unrecognized signal";
5583 }
5584 #undef SIGNAL
5585 }
5586
5587 GSource *
_g_main_create_unix_signal_watch(int signum)5588 _g_main_create_unix_signal_watch (int signum)
5589 {
5590 GSource *source;
5591 GUnixSignalWatchSource *unix_signal_source;
5592
5593 source = g_source_new (&g_unix_signal_funcs, sizeof (GUnixSignalWatchSource));
5594 unix_signal_source = (GUnixSignalWatchSource *) source;
5595
5596 unix_signal_source->signum = signum;
5597 unix_signal_source->pending = FALSE;
5598
5599 /* Set a default name on the source, just in case the caller does not. */
5600 g_source_set_static_name (source, signum_to_string (signum));
5601
5602 G_LOCK (unix_signal_lock);
5603 ref_unix_signal_handler_unlocked (signum);
5604 unix_signal_watches = g_slist_prepend (unix_signal_watches, unix_signal_source);
5605 dispatch_unix_signals_unlocked ();
5606 G_UNLOCK (unix_signal_lock);
5607
5608 return source;
5609 }
5610
5611 static void
g_unix_signal_watch_finalize(GSource * source)5612 g_unix_signal_watch_finalize (GSource *source)
5613 {
5614 GUnixSignalWatchSource *unix_signal_source;
5615
5616 unix_signal_source = (GUnixSignalWatchSource *) source;
5617
5618 G_LOCK (unix_signal_lock);
5619 unref_unix_signal_handler_unlocked (unix_signal_source->signum);
5620 unix_signal_watches = g_slist_remove (unix_signal_watches, source);
5621 G_UNLOCK (unix_signal_lock);
5622 }
5623
5624 static void
g_child_watch_finalize(GSource * source)5625 g_child_watch_finalize (GSource *source)
5626 {
5627 G_LOCK (unix_signal_lock);
5628 unix_child_watches = g_slist_remove (unix_child_watches, source);
5629 unref_unix_signal_handler_unlocked (SIGCHLD);
5630 G_UNLOCK (unix_signal_lock);
5631 }
5632
5633 #endif /* G_OS_WIN32 */
5634
5635 static gboolean
g_child_watch_dispatch(GSource * source,GSourceFunc callback,gpointer user_data)5636 g_child_watch_dispatch (GSource *source,
5637 GSourceFunc callback,
5638 gpointer user_data)
5639 {
5640 GChildWatchSource *child_watch_source;
5641 GChildWatchFunc child_watch_callback = (GChildWatchFunc) callback;
5642
5643 child_watch_source = (GChildWatchSource *) source;
5644
5645 if (!callback)
5646 {
5647 g_warning ("Child watch source dispatched without callback. "
5648 "You must call g_source_set_callback().");
5649 return FALSE;
5650 }
5651
5652 (child_watch_callback) (child_watch_source->pid, child_watch_source->child_status, user_data);
5653
5654 /* We never keep a child watch source around as the child is gone */
5655 return FALSE;
5656 }
5657
5658 #ifndef G_OS_WIN32
5659
5660 static void
g_unix_signal_handler(int signum)5661 g_unix_signal_handler (int signum)
5662 {
5663 gint saved_errno = errno;
5664
5665 #if defined(G_ATOMIC_LOCK_FREE) && defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)
5666 g_atomic_int_set (&unix_signal_pending[signum], 1);
5667 g_atomic_int_set (&any_unix_signal_pending, 1);
5668 #else
5669 #warning "Can't use atomics in g_unix_signal_handler(): Unix signal handling will be racy"
5670 unix_signal_pending[signum] = 1;
5671 any_unix_signal_pending = 1;
5672 #endif
5673
5674 g_wakeup_signal (glib_worker_context->wakeup);
5675
5676 errno = saved_errno;
5677 }
5678
5679 #endif /* !G_OS_WIN32 */
5680
5681 /**
5682 * g_child_watch_source_new:
5683 * @pid: process to watch. On POSIX the positive pid of a child process. On
5684 * Windows a handle for a process (which doesn't have to be a child).
5685 *
5686 * Creates a new child_watch source.
5687 *
5688 * The source will not initially be associated with any #GMainContext
5689 * and must be added to one with g_source_attach() before it will be
5690 * executed.
5691 *
5692 * Note that child watch sources can only be used in conjunction with
5693 * `g_spawn...` when the %G_SPAWN_DO_NOT_REAP_CHILD flag is used.
5694 *
5695 * Note that on platforms where #GPid must be explicitly closed
5696 * (see g_spawn_close_pid()) @pid must not be closed while the
5697 * source is still active. Typically, you will want to call
5698 * g_spawn_close_pid() in the callback function for the source.
5699 *
5700 * On POSIX platforms, the following restrictions apply to this API
5701 * due to limitations in POSIX process interfaces:
5702 *
5703 * * @pid must be a child of this process
5704 * * @pid must be positive
5705 * * the application must not call `waitpid` with a non-positive
5706 * first argument, for instance in another thread
5707 * * the application must not wait for @pid to exit by any other
5708 * mechanism, including `waitpid(pid, ...)` or a second child-watch
5709 * source for the same @pid
5710 * * the application must not ignore `SIGCHLD`
5711 *
5712 * If any of those conditions are not met, this and related APIs will
5713 * not work correctly. This can often be diagnosed via a GLib warning
5714 * stating that `ECHILD` was received by `waitpid`.
5715 *
5716 * Calling `waitpid` for specific processes other than @pid remains a
5717 * valid thing to do.
5718 *
5719 * Returns: the newly-created child watch source
5720 *
5721 * Since: 2.4
5722 **/
5723 GSource *
g_child_watch_source_new(GPid pid)5724 g_child_watch_source_new (GPid pid)
5725 {
5726 GSource *source;
5727 GChildWatchSource *child_watch_source;
5728
5729 #ifndef G_OS_WIN32
5730 g_return_val_if_fail (pid > 0, NULL);
5731 #endif
5732
5733 source = g_source_new (&g_child_watch_funcs, sizeof (GChildWatchSource));
5734 child_watch_source = (GChildWatchSource *)source;
5735
5736 /* Set a default name on the source, just in case the caller does not. */
5737 g_source_set_static_name (source, "GChildWatchSource");
5738
5739 child_watch_source->pid = pid;
5740
5741 #ifdef G_OS_WIN32
5742 child_watch_source->poll.fd = (gintptr) pid;
5743 child_watch_source->poll.events = G_IO_IN;
5744
5745 g_source_add_poll (source, &child_watch_source->poll);
5746 #else /* G_OS_WIN32 */
5747 G_LOCK (unix_signal_lock);
5748 ref_unix_signal_handler_unlocked (SIGCHLD);
5749 unix_child_watches = g_slist_prepend (unix_child_watches, child_watch_source);
5750 if (waitpid (pid, &child_watch_source->child_status, WNOHANG) > 0)
5751 child_watch_source->child_exited = TRUE;
5752 G_UNLOCK (unix_signal_lock);
5753 #endif /* G_OS_WIN32 */
5754
5755 return source;
5756 }
5757
5758 /**
5759 * g_child_watch_add_full: (rename-to g_child_watch_add)
5760 * @priority: the priority of the idle source. Typically this will be in the
5761 * range between %G_PRIORITY_DEFAULT_IDLE and %G_PRIORITY_HIGH_IDLE.
5762 * @pid: process to watch. On POSIX the positive pid of a child process. On
5763 * Windows a handle for a process (which doesn't have to be a child).
5764 * @function: function to call
5765 * @data: data to pass to @function
5766 * @notify: (nullable): function to call when the idle is removed, or %NULL
5767 *
5768 * Sets a function to be called when the child indicated by @pid
5769 * exits, at the priority @priority.
5770 *
5771 * If you obtain @pid from g_spawn_async() or g_spawn_async_with_pipes()
5772 * you will need to pass %G_SPAWN_DO_NOT_REAP_CHILD as flag to
5773 * the spawn function for the child watching to work.
5774 *
5775 * In many programs, you will want to call g_spawn_check_wait_status()
5776 * in the callback to determine whether or not the child exited
5777 * successfully.
5778 *
5779 * Also, note that on platforms where #GPid must be explicitly closed
5780 * (see g_spawn_close_pid()) @pid must not be closed while the source
5781 * is still active. Typically, you should invoke g_spawn_close_pid()
5782 * in the callback function for the source.
5783 *
5784 * GLib supports only a single callback per process id.
5785 * On POSIX platforms, the same restrictions mentioned for
5786 * g_child_watch_source_new() apply to this function.
5787 *
5788 * This internally creates a main loop source using
5789 * g_child_watch_source_new() and attaches it to the main loop context
5790 * using g_source_attach(). You can do these steps manually if you
5791 * need greater control.
5792 *
5793 * Returns: the ID (greater than 0) of the event source.
5794 *
5795 * Since: 2.4
5796 **/
5797 guint
g_child_watch_add_full(gint priority,GPid pid,GChildWatchFunc function,gpointer data,GDestroyNotify notify)5798 g_child_watch_add_full (gint priority,
5799 GPid pid,
5800 GChildWatchFunc function,
5801 gpointer data,
5802 GDestroyNotify notify)
5803 {
5804 GSource *source;
5805 guint id;
5806
5807 g_return_val_if_fail (function != NULL, 0);
5808 #ifndef G_OS_WIN32
5809 g_return_val_if_fail (pid > 0, 0);
5810 #endif
5811
5812 source = g_child_watch_source_new (pid);
5813
5814 if (priority != G_PRIORITY_DEFAULT)
5815 g_source_set_priority (source, priority);
5816
5817 g_source_set_callback (source, (GSourceFunc) function, data, notify);
5818 id = g_source_attach (source, NULL);
5819 g_source_unref (source);
5820
5821 return id;
5822 }
5823
5824 /**
5825 * g_child_watch_add:
5826 * @pid: process id to watch. On POSIX the positive pid of a child
5827 * process. On Windows a handle for a process (which doesn't have
5828 * to be a child).
5829 * @function: function to call
5830 * @data: data to pass to @function
5831 *
5832 * Sets a function to be called when the child indicated by @pid
5833 * exits, at a default priority, %G_PRIORITY_DEFAULT.
5834 *
5835 * If you obtain @pid from g_spawn_async() or g_spawn_async_with_pipes()
5836 * you will need to pass %G_SPAWN_DO_NOT_REAP_CHILD as flag to
5837 * the spawn function for the child watching to work.
5838 *
5839 * Note that on platforms where #GPid must be explicitly closed
5840 * (see g_spawn_close_pid()) @pid must not be closed while the
5841 * source is still active. Typically, you will want to call
5842 * g_spawn_close_pid() in the callback function for the source.
5843 *
5844 * GLib supports only a single callback per process id.
5845 * On POSIX platforms, the same restrictions mentioned for
5846 * g_child_watch_source_new() apply to this function.
5847 *
5848 * This internally creates a main loop source using
5849 * g_child_watch_source_new() and attaches it to the main loop context
5850 * using g_source_attach(). You can do these steps manually if you
5851 * need greater control.
5852 *
5853 * Returns: the ID (greater than 0) of the event source.
5854 *
5855 * Since: 2.4
5856 **/
5857 guint
g_child_watch_add(GPid pid,GChildWatchFunc function,gpointer data)5858 g_child_watch_add (GPid pid,
5859 GChildWatchFunc function,
5860 gpointer data)
5861 {
5862 return g_child_watch_add_full (G_PRIORITY_DEFAULT, pid, function, data, NULL);
5863 }
5864
5865
5866 /* Idle functions */
5867
5868 static gboolean
g_idle_prepare(GSource * source,gint * timeout)5869 g_idle_prepare (GSource *source,
5870 gint *timeout)
5871 {
5872 *timeout = 0;
5873
5874 return TRUE;
5875 }
5876
5877 static gboolean
g_idle_check(GSource * source)5878 g_idle_check (GSource *source)
5879 {
5880 return TRUE;
5881 }
5882
5883 static gboolean
g_idle_dispatch(GSource * source,GSourceFunc callback,gpointer user_data)5884 g_idle_dispatch (GSource *source,
5885 GSourceFunc callback,
5886 gpointer user_data)
5887 {
5888 gboolean again;
5889
5890 if (!callback)
5891 {
5892 g_warning ("Idle source dispatched without callback. "
5893 "You must call g_source_set_callback().");
5894 return FALSE;
5895 }
5896
5897 again = callback (user_data);
5898
5899 TRACE (GLIB_IDLE_DISPATCH (source, source->context, callback, user_data, again));
5900
5901 return again;
5902 }
5903
5904 /**
5905 * g_idle_source_new:
5906 *
5907 * Creates a new idle source.
5908 *
5909 * The source will not initially be associated with any #GMainContext
5910 * and must be added to one with g_source_attach() before it will be
5911 * executed. Note that the default priority for idle sources is
5912 * %G_PRIORITY_DEFAULT_IDLE, as compared to other sources which
5913 * have a default priority of %G_PRIORITY_DEFAULT.
5914 *
5915 * Returns: the newly-created idle source
5916 **/
5917 GSource *
g_idle_source_new(void)5918 g_idle_source_new (void)
5919 {
5920 GSource *source;
5921
5922 source = g_source_new (&g_idle_funcs, sizeof (GSource));
5923 g_source_set_priority (source, G_PRIORITY_DEFAULT_IDLE);
5924
5925 /* Set a default name on the source, just in case the caller does not. */
5926 g_source_set_static_name (source, "GIdleSource");
5927
5928 return source;
5929 }
5930
5931 /**
5932 * g_idle_add_full: (rename-to g_idle_add)
5933 * @priority: the priority of the idle source. Typically this will be in the
5934 * range between %G_PRIORITY_DEFAULT_IDLE and %G_PRIORITY_HIGH_IDLE.
5935 * @function: function to call
5936 * @data: data to pass to @function
5937 * @notify: (nullable): function to call when the idle is removed, or %NULL
5938 *
5939 * Adds a function to be called whenever there are no higher priority
5940 * events pending.
5941 *
5942 * If the function returns %G_SOURCE_REMOVE or %FALSE it is automatically
5943 * removed from the list of event sources and will not be called again.
5944 *
5945 * See [memory management of sources][mainloop-memory-management] for details
5946 * on how to handle the return value and memory management of @data.
5947 *
5948 * This internally creates a main loop source using g_idle_source_new()
5949 * and attaches it to the global #GMainContext using g_source_attach(), so
5950 * the callback will be invoked in whichever thread is running that main
5951 * context. You can do these steps manually if you need greater control or to
5952 * use a custom main context.
5953 *
5954 * Returns: the ID (greater than 0) of the event source.
5955 **/
5956 guint
g_idle_add_full(gint priority,GSourceFunc function,gpointer data,GDestroyNotify notify)5957 g_idle_add_full (gint priority,
5958 GSourceFunc function,
5959 gpointer data,
5960 GDestroyNotify notify)
5961 {
5962 GSource *source;
5963 guint id;
5964
5965 g_return_val_if_fail (function != NULL, 0);
5966
5967 source = g_idle_source_new ();
5968
5969 if (priority != G_PRIORITY_DEFAULT_IDLE)
5970 g_source_set_priority (source, priority);
5971
5972 g_source_set_callback (source, function, data, notify);
5973 id = g_source_attach (source, NULL);
5974
5975 TRACE (GLIB_IDLE_ADD (source, g_main_context_default (), id, priority, function, data));
5976
5977 g_source_unref (source);
5978
5979 return id;
5980 }
5981
5982 /**
5983 * g_idle_add:
5984 * @function: function to call
5985 * @data: data to pass to @function.
5986 *
5987 * Adds a function to be called whenever there are no higher priority
5988 * events pending to the default main loop. The function is given the
5989 * default idle priority, %G_PRIORITY_DEFAULT_IDLE. If the function
5990 * returns %FALSE it is automatically removed from the list of event
5991 * sources and will not be called again.
5992 *
5993 * See [memory management of sources][mainloop-memory-management] for details
5994 * on how to handle the return value and memory management of @data.
5995 *
5996 * This internally creates a main loop source using g_idle_source_new()
5997 * and attaches it to the global #GMainContext using g_source_attach(), so
5998 * the callback will be invoked in whichever thread is running that main
5999 * context. You can do these steps manually if you need greater control or to
6000 * use a custom main context.
6001 *
6002 * Returns: the ID (greater than 0) of the event source.
6003 **/
6004 guint
g_idle_add(GSourceFunc function,gpointer data)6005 g_idle_add (GSourceFunc function,
6006 gpointer data)
6007 {
6008 return g_idle_add_full (G_PRIORITY_DEFAULT_IDLE, function, data, NULL);
6009 }
6010
6011 /**
6012 * g_idle_remove_by_data:
6013 * @data: the data for the idle source's callback.
6014 *
6015 * Removes the idle function with the given data.
6016 *
6017 * Returns: %TRUE if an idle source was found and removed.
6018 **/
6019 gboolean
g_idle_remove_by_data(gpointer data)6020 g_idle_remove_by_data (gpointer data)
6021 {
6022 return g_source_remove_by_funcs_user_data (&g_idle_funcs, data);
6023 }
6024
6025 /**
6026 * g_main_context_invoke:
6027 * @context: (nullable): a #GMainContext, or %NULL
6028 * @function: function to call
6029 * @data: data to pass to @function
6030 *
6031 * Invokes a function in such a way that @context is owned during the
6032 * invocation of @function.
6033 *
6034 * If @context is %NULL then the global default main context — as
6035 * returned by g_main_context_default() — is used.
6036 *
6037 * If @context is owned by the current thread, @function is called
6038 * directly. Otherwise, if @context is the thread-default main context
6039 * of the current thread and g_main_context_acquire() succeeds, then
6040 * @function is called and g_main_context_release() is called
6041 * afterwards.
6042 *
6043 * In any other case, an idle source is created to call @function and
6044 * that source is attached to @context (presumably to be run in another
6045 * thread). The idle source is attached with %G_PRIORITY_DEFAULT
6046 * priority. If you want a different priority, use
6047 * g_main_context_invoke_full().
6048 *
6049 * Note that, as with normal idle functions, @function should probably
6050 * return %FALSE. If it returns %TRUE, it will be continuously run in a
6051 * loop (and may prevent this call from returning).
6052 *
6053 * Since: 2.28
6054 **/
6055 void
g_main_context_invoke(GMainContext * context,GSourceFunc function,gpointer data)6056 g_main_context_invoke (GMainContext *context,
6057 GSourceFunc function,
6058 gpointer data)
6059 {
6060 g_main_context_invoke_full (context,
6061 G_PRIORITY_DEFAULT,
6062 function, data, NULL);
6063 }
6064
6065 /**
6066 * g_main_context_invoke_full:
6067 * @context: (nullable): a #GMainContext, or %NULL
6068 * @priority: the priority at which to run @function
6069 * @function: function to call
6070 * @data: data to pass to @function
6071 * @notify: (nullable): a function to call when @data is no longer in use, or %NULL.
6072 *
6073 * Invokes a function in such a way that @context is owned during the
6074 * invocation of @function.
6075 *
6076 * This function is the same as g_main_context_invoke() except that it
6077 * lets you specify the priority in case @function ends up being
6078 * scheduled as an idle and also lets you give a #GDestroyNotify for @data.
6079 *
6080 * @notify should not assume that it is called from any particular
6081 * thread or with any particular context acquired.
6082 *
6083 * Since: 2.28
6084 **/
6085 void
g_main_context_invoke_full(GMainContext * context,gint priority,GSourceFunc function,gpointer data,GDestroyNotify notify)6086 g_main_context_invoke_full (GMainContext *context,
6087 gint priority,
6088 GSourceFunc function,
6089 gpointer data,
6090 GDestroyNotify notify)
6091 {
6092 g_return_if_fail (function != NULL);
6093
6094 if (!context)
6095 context = g_main_context_default ();
6096
6097 if (g_main_context_is_owner (context))
6098 {
6099 while (function (data));
6100 if (notify != NULL)
6101 notify (data);
6102 }
6103
6104 else
6105 {
6106 GMainContext *thread_default;
6107
6108 thread_default = g_main_context_get_thread_default ();
6109
6110 if (!thread_default)
6111 thread_default = g_main_context_default ();
6112
6113 if (thread_default == context && g_main_context_acquire (context))
6114 {
6115 while (function (data));
6116
6117 g_main_context_release (context);
6118
6119 if (notify != NULL)
6120 notify (data);
6121 }
6122 else
6123 {
6124 GSource *source;
6125
6126 source = g_idle_source_new ();
6127 g_source_set_priority (source, priority);
6128 g_source_set_callback (source, function, data, notify);
6129 g_source_attach (source, context);
6130 g_source_unref (source);
6131 }
6132 }
6133 }
6134
6135 static gpointer
glib_worker_main(gpointer data)6136 glib_worker_main (gpointer data)
6137 {
6138 while (TRUE)
6139 {
6140 g_main_context_iteration (glib_worker_context, TRUE);
6141
6142 #ifdef G_OS_UNIX
6143 if (g_atomic_int_get (&any_unix_signal_pending))
6144 dispatch_unix_signals ();
6145 #endif
6146 }
6147
6148 return NULL; /* worst GCC warning message ever... */
6149 }
6150
6151 GMainContext *
g_get_worker_context(void)6152 g_get_worker_context (void)
6153 {
6154 static gsize initialised;
6155
6156 if (g_once_init_enter (&initialised))
6157 {
6158 /* mask all signals in the worker thread */
6159 #ifdef G_OS_UNIX
6160 sigset_t prev_mask;
6161 sigset_t all;
6162
6163 sigfillset (&all);
6164 pthread_sigmask (SIG_SETMASK, &all, &prev_mask);
6165 #endif
6166 glib_worker_context = g_main_context_new ();
6167 g_thread_new ("gmain", glib_worker_main, NULL);
6168 #ifdef G_OS_UNIX
6169 pthread_sigmask (SIG_SETMASK, &prev_mask, NULL);
6170 #endif
6171 g_once_init_leave (&initialised, TRUE);
6172 }
6173
6174 return glib_worker_context;
6175 }
6176
6177 /**
6178 * g_steal_fd:
6179 * @fd_ptr: (not optional) (inout): A pointer to a file descriptor
6180 *
6181 * Sets @fd_ptr to `-1`, returning the value that was there before.
6182 *
6183 * Conceptually, this transfers the ownership of the file descriptor
6184 * from the referenced variable to the caller of the function (i.e.
6185 * ‘steals’ the reference). This is very similar to g_steal_pointer(),
6186 * but for file descriptors.
6187 *
6188 * On POSIX platforms, this function is async-signal safe
6189 * (see [`signal(7)`](man:signal(7)) and
6190 * [`signal-safety(7)`](man:signal-safety(7))), making it safe to call from a
6191 * signal handler or a #GSpawnChildSetupFunc.
6192 *
6193 * Returns: the value that @fd_ptr previously had
6194 * Since: 2.70
6195 */
6196