/* GLIB - Library of useful routines for C programming * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald * * gmain.c: Main loop abstraction, timeouts, and idle functions * Copyright 1998 Owen Taylor * * SPDX-License-Identifier: LGPL-2.1-or-later * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, see . */ /* * Modified by the GLib Team and others 1997-2000. See the AUTHORS * file for a list of people on the GLib Team. See the ChangeLog * files for a list of changes. These files are distributed with * GLib at ftp://ftp.gtk.org/pub/gtk/. */ /* * MT safe */ #include "config.h" #include "glib.h" #include "glibconfig.h" #include "glib_trace.h" /* Uncomment the next line (and the corresponding line in gpoll.c) to * enable debugging printouts if the environment variable * G_MAIN_POLL_DEBUG is set to some value. */ /* #define G_MAIN_POLL_DEBUG */ #ifdef _WIN32 /* Always enable debugging printout on Windows, as it is more often * needed there... */ #define G_MAIN_POLL_DEBUG #endif /* We need to include this as early as possible, because on some * platforms like AIX, redefines the names we use for * GPollFD struct members. * See https://gitlab.gnome.org/GNOME/glib/-/issues/3500 */ #ifdef HAVE_POLL_H #include #endif #ifdef G_OS_UNIX #include "glib-unix.h" #include #ifdef HAVE_EVENTFD #include #endif #endif #include #include #include #include #ifdef HAVE_SYS_TIME_H #include #endif /* HAVE_SYS_TIME_H */ #ifdef G_OS_UNIX #include #endif /* G_OS_UNIX */ #include #include #ifdef HAVE_PIDFD #include #include #include /* P_PIDFD */ #ifndef W_EXITCODE #define W_EXITCODE(ret, sig) ((ret) << 8 | (sig)) #endif #ifndef W_STOPCODE #define W_STOPCODE(sig) ((sig) << 8 | 0x7f) #endif #ifndef WCOREFLAG /* musl doesn’t define WCOREFLAG while glibc does. Unfortunately, there’s no way * to detect we’re building against musl, so just define it and hope. * See https://git.musl-libc.org/cgit/musl/tree/include/sys/wait.h#n51 */ #define WCOREFLAG 0x80 #endif #ifndef __W_CONTINUED /* Same as above, for musl */ #define __W_CONTINUED 0xffff #endif #endif /* HAVE_PIDFD */ #ifdef G_OS_WIN32 #include #endif #ifdef HAVE_MACH_MACH_TIME_H #include #endif #include "glib_trace.h" #include "gmain.h" #include "garray.h" #include "giochannel.h" #include "ghash.h" #include "ghook.h" #include "gqueue.h" #include "gstrfuncs.h" #include "gtestutils.h" #include "gthreadprivate.h" #include "gtrace-private.h" #ifdef G_OS_WIN32 #include "gwin32.h" #endif #ifdef G_MAIN_POLL_DEBUG #include "gtimer.h" #endif #include "gwakeup.h" #include "gmain-internal.h" #include "glib-init.h" #include "glib-private.h" /* Types */ typedef struct _GIdleSource GIdleSource; typedef struct _GTimeoutSource GTimeoutSource; typedef struct _GChildWatchSource GChildWatchSource; typedef struct _GUnixSignalWatchSource GUnixSignalWatchSource; typedef struct _GPollRec GPollRec; typedef struct _GSourceCallback GSourceCallback; typedef enum { G_SOURCE_READY = 1 << G_HOOK_FLAG_USER_SHIFT, G_SOURCE_CAN_RECURSE = 1 << (G_HOOK_FLAG_USER_SHIFT + 1), G_SOURCE_BLOCKED = 1 << (G_HOOK_FLAG_USER_SHIFT + 2) } GSourceFlags; typedef struct _GSourceList GSourceList; struct _GSourceList { GList link; GSource *head, *tail; gint priority; }; typedef struct _GMainWaiter GMainWaiter; struct _GMainWaiter { GCond *cond; GMutex *mutex; }; typedef struct _GMainDispatch GMainDispatch; struct _GMainDispatch { gint depth; GSource *source; }; #ifdef G_MAIN_POLL_DEBUG gboolean _g_main_poll_debug = FALSE; #endif struct _GMainContext { /* The following lock is used for both the list of sources * and the list of poll records */ GMutex mutex; GCond cond; GThread *owner; guint owner_count; GMainContextFlags flags; GSList *waiters; gint ref_count; /* (atomic) */ GHashTable *sources; /* guint -> GSource */ GPtrArray *pending_dispatches; gint64 timeout_usec; /* Timeout for current iteration */ guint next_id; GQueue source_lists; gint in_check_or_prepare; GPollRec *poll_records; guint n_poll_records; GPollFD *cached_poll_array; guint cached_poll_array_size; GWakeup *wakeup; GPollFD wake_up_rec; /* Flag indicating whether the set of fd's changed during a poll */ gboolean poll_changed; GPollFunc poll_func; gint64 time; gboolean time_is_fresh; }; struct _GSourceCallback { gint ref_count; /* (atomic) */ GSourceFunc func; gpointer data; GDestroyNotify notify; }; struct _GMainLoop { GMainContext *context; gboolean is_running; /* (atomic) */ gint ref_count; /* (atomic) */ }; struct _GIdleSource { GSource source; gboolean one_shot; }; struct _GTimeoutSource { GSource source; /* Measured in seconds if 'seconds' is TRUE, or milliseconds otherwise. */ guint interval; gboolean seconds; gboolean one_shot; }; struct _GChildWatchSource { GSource source; GPid pid; /* @poll is always used on Windows. * On Unix, poll.fd will be negative if PIDFD is unavailable. */ GPollFD poll; #ifndef G_OS_WIN32 gboolean child_maybe_exited; /* (atomic) */ #endif /* G_OS_WIN32 */ }; struct _GUnixSignalWatchSource { GSource source; int signum; gboolean pending; /* (atomic) */ }; struct _GPollRec { GPollFD *fd; GPollRec *prev; GPollRec *next; gint priority; }; struct _GSourcePrivate { GSList *child_sources; GSource *parent_source; gint64 ready_time; /* This is currently only used on UNIX, but we always declare it (and * let it remain empty on Windows) to avoid #ifdef all over the place. */ GSList *fds; GSourceDisposeFunc dispose; gboolean static_name; }; typedef struct _GSourceIter { GMainContext *context; gboolean may_modify; GList *current_list; GSource *source; } GSourceIter; #define LOCK_CONTEXT(context) g_mutex_lock (&context->mutex) #define UNLOCK_CONTEXT(context) g_mutex_unlock (&context->mutex) #define G_THREAD_SELF g_thread_self () #define SOURCE_DESTROYED(source) \ ((g_atomic_int_get (&((source)->flags)) & G_HOOK_FLAG_ACTIVE) == 0) #define SOURCE_BLOCKED(source) \ ((g_atomic_int_get (&((source)->flags)) & G_SOURCE_BLOCKED) != 0) /* Forward declarations */ static void g_source_unref_internal (GSource *source, GMainContext *context, gboolean have_lock); static void g_source_destroy_internal (GSource *source, GMainContext *context, gboolean have_lock); static void g_source_set_priority_unlocked (GSource *source, GMainContext *context, gint priority); static void g_child_source_remove_internal (GSource *child_source, GMainContext *context); static gboolean g_main_context_acquire_unlocked (GMainContext *context); static void g_main_context_release_unlocked (GMainContext *context); static gboolean g_main_context_prepare_unlocked (GMainContext *context, gint *priority); static gint g_main_context_query_unlocked (GMainContext *context, gint max_priority, gint64 *timeout_usec, GPollFD *fds, gint n_fds); static gboolean g_main_context_check_unlocked (GMainContext *context, gint max_priority, GPollFD *fds, gint n_fds); static void g_main_context_dispatch_unlocked (GMainContext *context); static void g_main_context_poll_unlocked (GMainContext *context, gint64 timeout_usec, int priority, GPollFD *fds, int n_fds); static void g_main_context_add_poll_unlocked (GMainContext *context, gint priority, GPollFD *fd); static void g_main_context_remove_poll_unlocked (GMainContext *context, GPollFD *fd); static void g_source_iter_init (GSourceIter *iter, GMainContext *context, gboolean may_modify); static gboolean g_source_iter_next (GSourceIter *iter, GSource **source); static void g_source_iter_clear (GSourceIter *iter); static gboolean g_timeout_dispatch (GSource *source, GSourceFunc callback, gpointer user_data); static gboolean g_child_watch_prepare (GSource *source, gint *timeout); static gboolean g_child_watch_check (GSource *source); static gboolean g_child_watch_dispatch (GSource *source, GSourceFunc callback, gpointer user_data); static void g_child_watch_finalize (GSource *source); #ifndef G_OS_WIN32 static void unref_unix_signal_handler_unlocked (int signum); #endif #ifdef G_OS_UNIX static void g_unix_signal_handler (int signum); static gboolean g_unix_signal_watch_prepare (GSource *source, gint *timeout); static gboolean g_unix_signal_watch_check (GSource *source); static gboolean g_unix_signal_watch_dispatch (GSource *source, GSourceFunc callback, gpointer user_data); static void g_unix_signal_watch_finalize (GSource *source); #endif static gboolean g_idle_prepare (GSource *source, gint *timeout); static gboolean g_idle_check (GSource *source); static gboolean g_idle_dispatch (GSource *source, GSourceFunc callback, gpointer user_data); static void block_source (GSource *source, GMainContext *context); static GMainContext *source_dup_main_context (GSource *source); /* Lock for serializing access for safe execution of * g_main_context_unref() with concurrent use of * g_source_destroy() and g_source_unref(). * * Locking order is source_destroy_lock, then context lock. */ static GRWLock source_destroy_lock; static GMainContext *glib_worker_context; #ifndef G_OS_WIN32 /* UNIX signals work by marking one of these variables then waking the * worker context to check on them and dispatch accordingly. * * Both variables must be accessed using atomic primitives, unless those atomic * primitives are implemented using fallback mutexes (as those aren’t safe in * an interrupt context). * * If using atomic primitives, the variables must be of type `int` (so they’re * the right size for the atomic primitives). Otherwise, use `sig_atomic_t` if * it’s available, which is guaranteed to be async-signal-safe (but it’s *not* * guaranteed to be thread-safe, which is why we use atomic primitives if * possible). * * Typically, `sig_atomic_t` is a typedef to `int`, but that’s not the case on * FreeBSD, so we can’t use it unconditionally if it’s defined. */ #if (defined(G_ATOMIC_LOCK_FREE) && defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)) || !defined(HAVE_SIG_ATOMIC_T) static volatile int unix_signal_pending[NSIG]; static volatile int any_unix_signal_pending; #else static volatile sig_atomic_t unix_signal_pending[NSIG]; static volatile sig_atomic_t any_unix_signal_pending; #endif /* Guards all the data below */ G_LOCK_DEFINE_STATIC (unix_signal_lock); static guint unix_signal_refcount[NSIG]; static GSList *unix_signal_watches; static GSList *unix_child_watches; GSourceFuncs g_unix_signal_funcs = { g_unix_signal_watch_prepare, g_unix_signal_watch_check, g_unix_signal_watch_dispatch, g_unix_signal_watch_finalize, NULL, NULL }; #endif /* !G_OS_WIN32 */ GSourceFuncs g_timeout_funcs = { NULL, /* prepare */ NULL, /* check */ g_timeout_dispatch, NULL, NULL, NULL }; GSourceFuncs g_child_watch_funcs = { g_child_watch_prepare, g_child_watch_check, g_child_watch_dispatch, g_child_watch_finalize, NULL, NULL }; GSourceFuncs g_idle_funcs = { g_idle_prepare, g_idle_check, g_idle_dispatch, NULL, NULL, NULL }; /** * g_main_context_ref: * @context: (not nullable): a main context * * Increases the reference count on a [struct@GLib.MainContext] object by one. * * Returns: the @context that was passed in (since 2.6) **/ GMainContext * g_main_context_ref (GMainContext *context) { int old_ref_count; g_return_val_if_fail (context != NULL, NULL); old_ref_count = g_atomic_int_add (&context->ref_count, 1); g_return_val_if_fail (old_ref_count > 0, NULL); return context; } static inline void poll_rec_list_free (GMainContext *context, GPollRec *list) { g_slice_free_chain (GPollRec, list, next); } /** * g_main_context_unref: * @context: (not nullable): a main context * * Decreases the reference count on a [struct@GLib.MainContext] object by one. * If * the result is zero, free the context and free all associated memory. **/ void g_main_context_unref (GMainContext *context) { GSourceIter iter; GSource *source; GList *sl_iter; GSList *s_iter, *remaining_sources = NULL; GSourceList *list; guint i; guint old_ref; GSource **pending_dispatches; gsize pending_dispatches_len; g_return_if_fail (context != NULL); g_return_if_fail (g_atomic_int_get (&context->ref_count) > 0); retry_decrement: old_ref = g_atomic_int_get (&context->ref_count); if (old_ref > 1) { if (!g_atomic_int_compare_and_exchange (&context->ref_count, old_ref, old_ref - 1)) goto retry_decrement; return; } g_rw_lock_writer_lock (&source_destroy_lock); /* if a weak ref got to the source_destroy lock first, we need to retry */ old_ref = g_atomic_int_add (&context->ref_count, -1); if (old_ref != 1) { g_rw_lock_writer_unlock (&source_destroy_lock); return; } LOCK_CONTEXT (context); pending_dispatches = (GSource **) g_ptr_array_steal (context->pending_dispatches, &pending_dispatches_len); UNLOCK_CONTEXT (context); /* Free pending dispatches */ for (i = 0; i < pending_dispatches_len; i++) g_source_unref_internal (pending_dispatches[i], context, FALSE); g_clear_pointer (&pending_dispatches, g_free); /* g_source_iter_next() assumes the context is locked. */ LOCK_CONTEXT (context); /* First collect all remaining sources from the sources lists and store a * new reference in a separate list. Also set the context of the sources * to NULL so that they can't access a partially destroyed context anymore. * * We have to do this first so that we have a strong reference to all * sources and destroying them below does not also free them, and so that * none of the sources can access the context from their finalize/dispose * functions. */ g_source_iter_init (&iter, context, FALSE); while (g_source_iter_next (&iter, &source)) { source->context = NULL; remaining_sources = g_slist_prepend (remaining_sources, g_source_ref (source)); } g_source_iter_clear (&iter); g_rw_lock_writer_unlock (&source_destroy_lock); /* Next destroy all sources. As we still hold a reference to all of them, * this won't cause any of them to be freed yet and especially prevents any * source that unrefs another source from its finalize function to be freed. */ for (s_iter = remaining_sources; s_iter; s_iter = s_iter->next) { source = s_iter->data; g_source_destroy_internal (source, context, TRUE); } /* the context is going to die now */ g_return_if_fail (old_ref > 0); sl_iter = context->source_lists.head; while (sl_iter != NULL) { list = sl_iter->data; sl_iter = sl_iter->next; g_slice_free (GSourceList, list); } g_hash_table_remove_all (context->sources); UNLOCK_CONTEXT (context); /* if the object has been reffed meanwhile by an internal weak ref, keep the * resources alive until the last reference is gone. */ if (old_ref == 1) { g_mutex_clear (&context->mutex); g_ptr_array_free (context->pending_dispatches, TRUE); g_free (context->cached_poll_array); poll_rec_list_free (context, context->poll_records); g_wakeup_free (context->wakeup); g_cond_clear (&context->cond); g_hash_table_unref (context->sources); g_free (context); } /* And now finally get rid of our references to the sources. This will cause * them to be freed unless something else still has a reference to them. Due * to setting the context pointers in the sources to NULL above, this won't * ever access the context or the internal linked list inside the GSource. * We already removed the sources completely from the context above. */ for (s_iter = remaining_sources; s_iter; s_iter = s_iter->next) { source = s_iter->data; g_source_unref_internal (source, NULL, FALSE); } g_slist_free (remaining_sources); } /* Helper function used by mainloop/overflow test. */ GMainContext * g_main_context_new_with_next_id (guint next_id) { GMainContext *ret = g_main_context_new (); ret->next_id = next_id; return ret; } /** * g_main_context_new: * * Creates a new [struct@GLib.MainContext] structure. * * Returns: (transfer full): the new main context **/ GMainContext * g_main_context_new (void) { return g_main_context_new_with_flags (G_MAIN_CONTEXT_FLAGS_NONE); } /** * g_main_context_new_with_flags: * @flags: a bitwise-OR combination of flags that can only be set at creation * time * * Creates a new [struct@GLib.MainContext] structure. * * Returns: (transfer full): the new main context * Since: 2.72 */ GMainContext * g_main_context_new_with_flags (GMainContextFlags flags) { static gsize initialised; GMainContext *context; if (g_once_init_enter (&initialised)) { #ifdef G_MAIN_POLL_DEBUG if (g_getenv ("G_MAIN_POLL_DEBUG") != NULL) _g_main_poll_debug = TRUE; #endif g_once_init_leave (&initialised, TRUE); } context = g_new0 (GMainContext, 1); TRACE (GLIB_MAIN_CONTEXT_NEW (context)); g_mutex_init (&context->mutex); g_cond_init (&context->cond); context->sources = g_hash_table_new (g_uint_hash, g_uint_equal); context->owner = NULL; context->flags = flags; context->waiters = NULL; context->ref_count = 1; context->next_id = 1; context->poll_func = g_poll; context->cached_poll_array = NULL; context->cached_poll_array_size = 0; context->pending_dispatches = g_ptr_array_new (); context->time_is_fresh = FALSE; context->wakeup = g_wakeup_new (); g_wakeup_get_pollfd (context->wakeup, &context->wake_up_rec); g_main_context_add_poll_unlocked (context, 0, &context->wake_up_rec); #ifdef G_MAIN_POLL_DEBUG if (_g_main_poll_debug) g_print ("created context=%p\n", context); #endif return context; } /** * g_main_context_default: * * Returns the global-default main context. * * This is the main context * used for main loop functions when a main loop is not explicitly * specified, and corresponds to the ‘main’ main loop. See also * [func@GLib.MainContext.get_thread_default]. * * Returns: (transfer none): the global-default main context. **/ GMainContext * g_main_context_default (void) { static GMainContext *default_main_context = NULL; if (g_once_init_enter_pointer (&default_main_context)) { GMainContext *context; context = g_main_context_new (); TRACE (GLIB_MAIN_CONTEXT_DEFAULT (context)); #ifdef G_MAIN_POLL_DEBUG if (_g_main_poll_debug) g_print ("global-default main context=%p\n", context); #endif g_once_init_leave_pointer (&default_main_context, context); } return default_main_context; } static void free_context (gpointer data) { GMainContext *context = data; TRACE (GLIB_MAIN_CONTEXT_FREE (context)); g_main_context_release (context); if (context) g_main_context_unref (context); } static void free_context_stack (gpointer data) { g_queue_free_full((GQueue *) data, (GDestroyNotify) free_context); } static GPrivate thread_context_stack = G_PRIVATE_INIT (free_context_stack); /** * g_main_context_push_thread_default: * @context: (nullable): a main context, or `NULL` for the global-default * main context * * Acquires @context and sets it as the thread-default context for the * current thread. This will cause certain asynchronous operations * (such as most [Gio](../gio/index.html)-based I/O) which are * started in this thread to run under @context and deliver their * results to its main loop, rather than running under the global * default main context in the main thread. Note that calling this function * changes the context returned by [func@GLib.MainContext.get_thread_default], * not the one returned by [func@GLib.MainContext.default], so it does not * affect the context used by functions like [func@GLib.idle_add]. * * Normally you would call this function shortly after creating a new * thread, passing it a [struct@GLib.MainContext] which will be run by a * [struct@GLib.MainLoop] in that thread, to set a new default context for all * async operations in that thread. In this case you may not need to * ever call [method@GLib.MainContext.pop_thread_default], assuming you want * the new [struct@GLib.MainContext] to be the default for the whole lifecycle * of the thread. * * If you don’t have control over how the new thread was created (e.g. * in the new thread isn’t newly created, or if the thread life * cycle is managed by a #GThreadPool), it is always suggested to wrap * the logic that needs to use the new [struct@GLib.MainContext] inside a * [method@GLib.MainContext.push_thread_default] / * [method@GLib.MainContext.pop_thread_default] pair, otherwise threads that * are re-used will end up never explicitly releasing the * [struct@GLib.MainContext] reference they hold. * * In some cases you may want to schedule a single operation in a * non-default context, or temporarily use a non-default context in * the main thread. In that case, you can wrap the call to the * asynchronous operation inside a * [method@GLib.MainContext.push_thread_default] / * [method@GLib.MainContext.pop_thread_default] pair, but it is up to you to * ensure that no other asynchronous operations accidentally get * started while the non-default context is active. * * Beware that libraries that predate this function may not correctly * handle being used from a thread with a thread-default context. For example, * see `g_file_supports_thread_contexts()`. * * Since: 2.22 **/ void g_main_context_push_thread_default (GMainContext *context) { GQueue *stack; gboolean acquired_context; acquired_context = g_main_context_acquire (context); g_return_if_fail (acquired_context); if (context == g_main_context_default ()) context = NULL; else if (context) g_main_context_ref (context); stack = g_private_get (&thread_context_stack); if (!stack) { stack = g_queue_new (); g_private_set (&thread_context_stack, stack); } g_queue_push_head (stack, context); TRACE (GLIB_MAIN_CONTEXT_PUSH_THREAD_DEFAULT (context)); } /** * g_main_context_pop_thread_default: * @context: (nullable): a main context, or `NULL` for the global-default * main context * * Pops @context off the thread-default context stack (verifying that * it was on the top of the stack). * * Since: 2.22 **/ void g_main_context_pop_thread_default (GMainContext *context) { GQueue *stack; if (context == g_main_context_default ()) context = NULL; stack = g_private_get (&thread_context_stack); g_return_if_fail (stack != NULL); g_return_if_fail (g_queue_peek_head (stack) == context); TRACE (GLIB_MAIN_CONTEXT_POP_THREAD_DEFAULT (context)); g_queue_pop_head (stack); g_main_context_release (context); if (context) g_main_context_unref (context); } /** * g_main_context_get_thread_default: * * Gets the thread-default main context for this thread. * * Asynchronous operations that want to be able to be run in contexts other than * the default one should call this method or * [func@GLib.MainContext.ref_thread_default] to get a * [struct@GLib.MainContext] to add their [struct@GLib.Source]s to. (Note that * even in single-threaded programs applications may sometimes want to * temporarily push a non-default context, so it is not safe to assume that * this will always return `NULL` if you are running in the default thread.) * * If you need to hold a reference on the context, use * [func@GLib.MainContext.ref_thread_default] instead. * * Returns: (transfer none) (nullable): the thread-default main context, or * `NULL` if the thread-default context is the global-default main context * Since: 2.22 **/ GMainContext * g_main_context_get_thread_default (void) { GQueue *stack; stack = g_private_get (&thread_context_stack); if (stack) return g_queue_peek_head (stack); else return NULL; } /** * g_main_context_ref_thread_default: * * Gets a reference to the thread-default [struct@GLib.MainContext] for this * thread * * This is the same as [func@GLib.MainContext.get_thread_default], but it also * adds a reference to the returned main context with [method@GLib.MainContext.ref]. * In addition, unlike * [func@GLib.MainContext.get_thread_default], if the thread-default context * is the global-default context, this will return that * [struct@GLib.MainContext] (with a ref added to it) rather than returning * `NULL`. * * Returns: (transfer full) (not nullable): the thread-default main context * Since: 2.32 */ GMainContext * g_main_context_ref_thread_default (void) { GMainContext *context; context = g_main_context_get_thread_default (); if (!context) context = g_main_context_default (); return g_main_context_ref (context); } /* Hooks for adding to the main loop */ /** * g_source_new: * @source_funcs: structure containing functions that implement * the source‘s behavior * @struct_size: size of the [struct@GLib.Source] structure to create, in bytes * * Creates a new [struct@GLib.Source] structure. * * The size is specified to * allow creating structures derived from [struct@GLib.Source] that contain * additional data. The size passed in must be at least * `sizeof (GSource)`. * * The source will not initially be associated with any [struct@GLib.MainContext] * and must be added to one with [method@GLib.Source.attach] before it will be * executed. * * Returns: (transfer full): the newly-created source **/ GSource * g_source_new (GSourceFuncs *source_funcs, guint struct_size) { GSource *source; g_return_val_if_fail (source_funcs != NULL, NULL); g_return_val_if_fail (struct_size >= sizeof (GSource), NULL); source = (GSource*) g_malloc0 (struct_size); source->priv = g_slice_new0 (GSourcePrivate); source->source_funcs = source_funcs; g_atomic_int_set (&source->ref_count, 1); source->priority = G_PRIORITY_DEFAULT; g_atomic_int_set (&source->flags, G_HOOK_FLAG_ACTIVE); source->priv->ready_time = -1; /* NULL/0 initialization for all other fields */ TRACE (GLIB_SOURCE_NEW (source, source_funcs->prepare, source_funcs->check, source_funcs->dispatch, source_funcs->finalize, struct_size)); return source; } /** * g_source_set_dispose_function: * @source: a source to set the dispose function on * @dispose: dispose function to set on the source * * Set @dispose as dispose function on @source. * * The @dispose function will be called once the reference count of @source * reaches zero but before any of the state of the source is freed, especially * before the finalize function (set as part of the [type@GLib.SourceFuncs]) is * called. * * This means that at this point @source is still a valid [struct@GLib.Source] * and it is allow for the reference count to increase again until @dispose * returns. * * The dispose function can be used to clear any ‘weak’ references to * the @source in other data structures in a thread-safe way where it is * possible for another thread to increase the reference count of @source again * while it is being freed. * * The finalize function can not be used for this purpose as at that * point @source is already partially freed and not valid any more. * * This should only ever be called from [struct@GLib.Source] implementations. * * Since: 2.64 **/ void g_source_set_dispose_function (GSource *source, GSourceDisposeFunc dispose) { gboolean was_unset G_GNUC_UNUSED; g_return_if_fail (source != NULL); g_return_if_fail (g_atomic_int_get (&source->ref_count) > 0); was_unset = g_atomic_pointer_compare_and_exchange (&source->priv->dispose, NULL, dispose); g_return_if_fail (was_unset); } /* Holds context's lock */ static void g_source_iter_init (GSourceIter *iter, GMainContext *context, gboolean may_modify) { iter->context = context; iter->current_list = NULL; iter->source = NULL; iter->may_modify = may_modify; } /* Holds context's lock */ static gboolean g_source_iter_next (GSourceIter *iter, GSource **source) { GSource *next_source; if (iter->source) next_source = iter->source->next; else next_source = NULL; if (!next_source) { if (iter->current_list) iter->current_list = iter->current_list->next; else iter->current_list = iter->context->source_lists.head; if (iter->current_list) { GSourceList *source_list = iter->current_list->data; next_source = source_list->head; } } /* Note: unreffing iter->source could potentially cause its * GSourceList to be removed from source_lists (if iter->source is * the only source in its list, and it is destroyed), so we have to * keep it reffed until after we advance iter->current_list, above. * * Also we first have to ref the next source before unreffing the * previous one as unreffing the previous source can potentially * free the next one. */ if (next_source && iter->may_modify) g_source_ref (next_source); if (iter->source && iter->may_modify) g_source_unref_internal (iter->source, iter->context, TRUE); iter->source = next_source; *source = iter->source; return *source != NULL; } /* Holds context's lock. Only necessary to call if you broke out of * the g_source_iter_next() loop early. */ static void g_source_iter_clear (GSourceIter *iter) { if (iter->source && iter->may_modify) { g_source_unref_internal (iter->source, iter->context, TRUE); iter->source = NULL; } } /* Holds context's lock */ static GSourceList * find_source_list_for_priority (GMainContext *context, gint priority, gboolean create) { GList *iter; GSourceList *source_list; for (iter = context->source_lists.head; iter; iter = iter->next) { source_list = iter->data; if (source_list->priority == priority) return source_list; if (source_list->priority > priority) { if (!create) return NULL; source_list = g_slice_new0 (GSourceList); source_list->link.data = source_list; source_list->priority = priority; g_queue_insert_before_link (&context->source_lists, iter, &source_list->link); return source_list; } } if (!create) return NULL; source_list = g_slice_new0 (GSourceList); source_list->link.data = source_list; source_list->priority = priority; g_queue_push_tail_link (&context->source_lists, &source_list->link); return source_list; } /* Holds context's lock */ static void source_add_to_context (GSource *source, GMainContext *context) { GSourceList *source_list; GSource *prev, *next; source_list = find_source_list_for_priority (context, source->priority, TRUE); if (source->priv->parent_source) { g_assert (source_list->head != NULL); /* Put the source immediately before its parent */ prev = source->priv->parent_source->prev; next = source->priv->parent_source; } else { prev = source_list->tail; next = NULL; } source->next = next; if (next) next->prev = source; else source_list->tail = source; source->prev = prev; if (prev) prev->next = source; else source_list->head = source; } /* Holds context's lock */ static void source_remove_from_context (GSource *source, GMainContext *context) { GSourceList *source_list; source_list = find_source_list_for_priority (context, source->priority, FALSE); g_return_if_fail (source_list != NULL); if (source->prev) source->prev->next = source->next; else source_list->head = source->next; if (source->next) source->next->prev = source->prev; else source_list->tail = source->prev; source->prev = NULL; source->next = NULL; if (source_list->head == NULL) { g_queue_unlink (&context->source_lists, &source_list->link); g_slice_free (GSourceList, source_list); } } static guint g_source_attach_unlocked (GSource *source, GMainContext *context, gboolean do_wakeup) { GSList *tmp_list; guint id; /* The counter may have wrapped, so we must ensure that we do not * reuse the source id of an existing source. */ do id = context->next_id++; while (id == 0 || g_hash_table_contains (context->sources, &id)); source->context = context; source->source_id = id; g_source_ref (source); g_hash_table_add (context->sources, &source->source_id); source_add_to_context (source, context); if (!SOURCE_BLOCKED (source)) { tmp_list = source->poll_fds; while (tmp_list) { g_main_context_add_poll_unlocked (context, source->priority, tmp_list->data); tmp_list = tmp_list->next; } for (tmp_list = source->priv->fds; tmp_list; tmp_list = tmp_list->next) g_main_context_add_poll_unlocked (context, source->priority, tmp_list->data); } tmp_list = source->priv->child_sources; while (tmp_list) { g_source_attach_unlocked (tmp_list->data, context, FALSE); tmp_list = tmp_list->next; } /* If another thread has acquired the context, wake it up since it * might be in poll() right now. */ if (do_wakeup && (context->flags & G_MAIN_CONTEXT_FLAGS_OWNERLESS_POLLING || (context->owner && context->owner != G_THREAD_SELF))) { g_wakeup_signal (context->wakeup); } g_trace_mark (G_TRACE_CURRENT_TIME, 0, "GLib", "g_source_attach", "%s to context %p", (g_source_get_name (source) != NULL) ? g_source_get_name (source) : "(unnamed)", context); return source->source_id; } /** * g_source_attach: * @source: a source * @context: (nullable): a main context (if `NULL`, the global-default * main context will be used) * * Adds a [struct@GLib.Source] to a @context so that it will be executed within * that context. * * Remove it by calling [method@GLib.Source.destroy]. * * This function is safe to call from any thread, regardless of which thread * the @context is running in. * * Returns: the ID (greater than 0) for the source within the * [struct@GLib.MainContext] **/ guint g_source_attach (GSource *source, GMainContext *context) { guint result = 0; g_return_val_if_fail (source != NULL, 0); g_return_val_if_fail (g_atomic_int_get (&source->ref_count) > 0, 0); g_return_val_if_fail (source->context == NULL, 0); g_return_val_if_fail (!SOURCE_DESTROYED (source), 0); if (!context) context = g_main_context_default (); LOCK_CONTEXT (context); result = g_source_attach_unlocked (source, context, TRUE); TRACE (GLIB_MAIN_SOURCE_ATTACH (g_source_get_name (source), source, context, result)); UNLOCK_CONTEXT (context); return result; } static void g_source_destroy_internal (GSource *source, GMainContext *context, gboolean have_lock) { TRACE (GLIB_MAIN_SOURCE_DESTROY (g_source_get_name (source), source, context)); if (!have_lock) LOCK_CONTEXT (context); if (!SOURCE_DESTROYED (source)) { GSList *tmp_list; gpointer old_cb_data; GSourceCallbackFuncs *old_cb_funcs; g_atomic_int_and (&source->flags, ~G_HOOK_FLAG_ACTIVE); old_cb_data = source->callback_data; old_cb_funcs = source->callback_funcs; source->callback_data = NULL; source->callback_funcs = NULL; if (old_cb_funcs) { UNLOCK_CONTEXT (context); old_cb_funcs->unref (old_cb_data); LOCK_CONTEXT (context); } if (!SOURCE_BLOCKED (source)) { tmp_list = source->poll_fds; while (tmp_list) { g_main_context_remove_poll_unlocked (context, tmp_list->data); tmp_list = tmp_list->next; } for (tmp_list = source->priv->fds; tmp_list; tmp_list = tmp_list->next) g_main_context_remove_poll_unlocked (context, tmp_list->data); } while (source->priv->child_sources) g_child_source_remove_internal (source->priv->child_sources->data, context); if (source->priv->parent_source) g_child_source_remove_internal (source, context); g_source_unref_internal (source, context, TRUE); } if (!have_lock) UNLOCK_CONTEXT (context); } static GMainContext * source_dup_main_context (GSource *source) { GMainContext *ret = NULL; g_rw_lock_reader_lock (&source_destroy_lock); ret = source->context; if (ret) g_atomic_int_inc (&ret->ref_count); g_rw_lock_reader_unlock (&source_destroy_lock); return ret; } /** * g_source_destroy: * @source: a source * * Removes a source from its [struct@GLib.MainContext], if any, and marks it as * destroyed. * * The source cannot be subsequently added to another * context. It is safe to call this on sources which have already been * removed from their context. * * This does not unref the [struct@GLib.Source]: if you still hold a reference, * use [method@GLib.Source.unref] to drop it. * * This function is safe to call from any thread, regardless of which thread * the [struct@GLib.MainContext] is running in. * * If the source is currently attached to a [struct@GLib.MainContext], * destroying it will effectively unset the callback similar to calling * [method@GLib.Source.set_callback]. This can mean, that the data’s * [callback@GLib.DestroyNotify] gets called right away. */ void g_source_destroy (GSource *source) { GMainContext *context; g_return_if_fail (source != NULL); g_return_if_fail (g_atomic_int_get (&source->ref_count) > 0); context = source_dup_main_context (source); if (context) { g_source_destroy_internal (source, context, FALSE); g_main_context_unref (context); } else g_atomic_int_and (&source->flags, ~G_HOOK_FLAG_ACTIVE); } /** * g_source_get_id: * @source: a source * * Returns the numeric ID for a particular source. * * The ID of a source * is a positive integer which is unique within a particular main loop * context. The reverse mapping from ID to source is done by * [method@GLib.MainContext.find_source_by_id]. * * You can only call this function while the source is associated to a * [struct@GLib.MainContext] instance; calling this function before * [method@GLib.Source.attach] or after [method@GLib.Source.destroy] yields * undefined behavior. The ID returned is unique within the * [struct@GLib.MainContext] instance passed to [method@GLib.Source.attach]. * * Returns: the ID (greater than 0) for the source **/ guint g_source_get_id (GSource *source) { guint result; GMainContext *context; g_return_val_if_fail (source != NULL, 0); g_return_val_if_fail (g_atomic_int_get (&source->ref_count) > 0, 0); context = source_dup_main_context (source); g_return_val_if_fail (context != NULL, 0); LOCK_CONTEXT (context); result = source->source_id; UNLOCK_CONTEXT (context); g_main_context_unref (context); return result; } /** * g_source_get_context: * @source: a source * * Gets the [struct@GLib.MainContext] with which the source is associated. * * You can call this on a source that has been destroyed, provided * that the [struct@GLib.MainContext] it was attached to still exists (in which * case it will return that [struct@GLib.MainContext]). In particular, you can * always call this function on the source returned from * [func@GLib.main_current_source]. But calling this function on a source * whose [struct@GLib.MainContext] has been destroyed is an error. * * If the associated [struct@GLib.MainContext] could be destroy concurrently from * a different thread, then this function is not safe to call and * [method@GLib.Source.dup_context] should be used instead. * * Returns: (transfer none) (nullable): the main context with which the * source is associated, or `NULL` if the context has not yet been added to a * source **/ GMainContext * g_source_get_context (GSource *source) { g_return_val_if_fail (source != NULL, NULL); g_return_val_if_fail (g_atomic_int_get (&source->ref_count) > 0, NULL); g_return_val_if_fail (source->context != NULL || !SOURCE_DESTROYED (source), NULL); return source->context; } /** * g_source_dup_context: * @source: a source * * Gets a reference to the [struct@GLib.MainContext] with which the source is * associated. * * You can call this on a source that has been destroyed. You can * always call this function on the source returned from * [func@GLib.main_current_source]. * * Returns: (transfer full) (nullable): the [struct@GLib.MainContext] with which * the source is associated, or `NULL` if the context has not yet been added * to a source * Since: 2.86 **/ GMainContext * g_source_dup_context (GSource *source) { g_return_val_if_fail (source != NULL, NULL); g_return_val_if_fail (g_atomic_int_get (&source->ref_count) > 0, NULL); g_return_val_if_fail (source->context != NULL || !SOURCE_DESTROYED (source), NULL); return source_dup_main_context (source); } /** * g_source_add_poll: * @source:a source * @fd: a [struct@GLib.PollFD] structure holding information about a file * descriptor to watch * * Adds a file descriptor to the set of file descriptors polled for * this source. * * This is usually combined with [ctor@GLib.Source.new] to add an * event source. The event source’s check function will typically test * the @revents field in the [struct@GLib.PollFD] struct and return true if * events need to be processed. * * This API is only intended to be used by implementations of [struct@GLib.Source]. * Do not call this API on a [struct@GLib.Source] that you did not create. * * Using this API forces the linear scanning of event sources on each * main loop iteration. Newly-written event sources should try to use * `g_source_add_unix_fd()` instead of this API. **/ void g_source_add_poll (GSource *source, GPollFD *fd) { GMainContext *context; g_return_if_fail (source != NULL); g_return_if_fail (g_atomic_int_get (&source->ref_count) > 0); g_return_if_fail (fd != NULL); g_return_if_fail (!SOURCE_DESTROYED (source)); context = source_dup_main_context (source); if (context) LOCK_CONTEXT (context); source->poll_fds = g_slist_prepend (source->poll_fds, fd); if (context) { if (!SOURCE_BLOCKED (source)) g_main_context_add_poll_unlocked (context, source->priority, fd); UNLOCK_CONTEXT (context); g_main_context_unref (context); } } /** * g_source_remove_poll: * @source:a source * @fd: a [struct@GLib.PollFD] structure previously passed to * [method@GLib.Source.add_poll] * * Removes a file descriptor from the set of file descriptors polled for * this source. * * This API is only intended to be used by implementations of [struct@GLib.Source]. * Do not call this API on a [struct@GLib.Source] that you did not create. **/ void g_source_remove_poll (GSource *source, GPollFD *fd) { GMainContext *context; g_return_if_fail (source != NULL); g_return_if_fail (g_atomic_int_get (&source->ref_count) > 0); g_return_if_fail (fd != NULL); g_return_if_fail (!SOURCE_DESTROYED (source)); context = source_dup_main_context (source); if (context) LOCK_CONTEXT (context); source->poll_fds = g_slist_remove (source->poll_fds, fd); if (context) { if (!SOURCE_BLOCKED (source)) g_main_context_remove_poll_unlocked (context, fd); UNLOCK_CONTEXT (context); g_main_context_unref (context); } } /** * g_source_add_child_source: * @source:a source * @child_source: a second source that @source should ‘poll’ * * Adds @child_source to @source as a ‘polled’ source. * * When @source is added to a [struct@GLib.MainContext], @child_source will be * automatically added with the same priority. When @child_source is triggered, * it will cause @source to dispatch (in addition to calling its own callback), * and when @source is destroyed, it will destroy @child_source as well. * * The @source will also still be dispatched if its own prepare/check functions * indicate that it is ready. * * If you don’t need @child_source to do anything on its own when it * triggers, you can call `g_source_set_dummy_callback()` on it to set a * callback that does nothing (except return true if appropriate). * * The @source will hold a reference on @child_source while @child_source * is attached to it. * * This API is only intended to be used by implementations of [struct@GLib.Source]. * Do not call this API on a [struct@GLib.Source] that you did not create. * * Since: 2.28 **/ void g_source_add_child_source (GSource *source, GSource *child_source) { GMainContext *context; g_return_if_fail (source != NULL); g_return_if_fail (g_atomic_int_get (&source->ref_count) > 0); g_return_if_fail (child_source != NULL); g_return_if_fail (g_atomic_int_get (&child_source->ref_count) > 0); g_return_if_fail (!SOURCE_DESTROYED (source)); g_return_if_fail (!SOURCE_DESTROYED (child_source)); g_return_if_fail (child_source->context == NULL); g_return_if_fail (child_source->priv->parent_source == NULL); context = source_dup_main_context (source); if (context) LOCK_CONTEXT (context); TRACE (GLIB_SOURCE_ADD_CHILD_SOURCE (source, child_source)); source->priv->child_sources = g_slist_prepend (source->priv->child_sources, g_source_ref (child_source)); child_source->priv->parent_source = source; g_source_set_priority_unlocked (child_source, NULL, source->priority); if (SOURCE_BLOCKED (source)) block_source (child_source, NULL); if (context) { g_source_attach_unlocked (child_source, context, TRUE); UNLOCK_CONTEXT (context); g_main_context_unref (context); } } static void g_child_source_remove_internal (GSource *child_source, GMainContext *context) { GSource *parent_source = child_source->priv->parent_source; parent_source->priv->child_sources = g_slist_remove (parent_source->priv->child_sources, child_source); child_source->priv->parent_source = NULL; g_source_destroy_internal (child_source, context, TRUE); g_source_unref_internal (child_source, context, TRUE); } /** * g_source_remove_child_source: * @source:a source * @child_source: a source previously passed to * [method@GLib.Source.add_child_source] * * Detaches @child_source from @source and destroys it. * * This API is only intended to be used by implementations of [struct@GLib.Source]. * Do not call this API on a [struct@GLib.Source] that you did not create. * * Since: 2.28 **/ void g_source_remove_child_source (GSource *source, GSource *child_source) { GMainContext *context; g_return_if_fail (source != NULL); g_return_if_fail (g_atomic_int_get (&source->ref_count) > 0); g_return_if_fail (child_source != NULL); g_return_if_fail (g_atomic_int_get (&child_source->ref_count) > 0); g_return_if_fail (child_source->priv->parent_source == source); g_return_if_fail (!SOURCE_DESTROYED (source)); g_return_if_fail (!SOURCE_DESTROYED (child_source)); context = source_dup_main_context (source); if (context) LOCK_CONTEXT (context); g_child_source_remove_internal (child_source, context); if (context) { UNLOCK_CONTEXT (context); g_main_context_unref (context); } } static void g_source_callback_ref (gpointer cb_data) { GSourceCallback *callback = cb_data; g_atomic_int_inc (&callback->ref_count); } static void g_source_callback_unref (gpointer cb_data) { GSourceCallback *callback = cb_data; if (g_atomic_int_dec_and_test (&callback->ref_count)) { if (callback->notify) callback->notify (callback->data); g_free (callback); } } static void g_source_callback_get (gpointer cb_data, GSource *source, GSourceFunc *func, gpointer *data) { GSourceCallback *callback = cb_data; *func = callback->func; *data = callback->data; } static GSourceCallbackFuncs g_source_callback_funcs = { g_source_callback_ref, g_source_callback_unref, g_source_callback_get, }; /** * g_source_set_callback_indirect: * @source: the source * @callback_data: pointer to callback data ‘object’ * @callback_funcs: functions for reference counting @callback_data * and getting the callback and data * * Sets the callback function storing the data as a reference counted callback * ‘object’. * * This is used internally. Note that calling * [method@GLib.Source.set_callback_indirect] assumes * an initial reference count on @callback_data, and thus * `callback_funcs->unref` will eventually be called once more than * `callback_funcs->ref`. * * It is safe to call this function multiple times on a source which has already * been attached to a context. The changes will take effect for the next time * the source is dispatched after this call returns. **/ void g_source_set_callback_indirect (GSource *source, gpointer callback_data, GSourceCallbackFuncs *callback_funcs) { GMainContext *context; gpointer old_cb_data; GSourceCallbackFuncs *old_cb_funcs; g_return_if_fail (source != NULL); g_return_if_fail (g_atomic_int_get (&source->ref_count) > 0); g_return_if_fail (callback_funcs != NULL || callback_data == NULL); context = source_dup_main_context (source); if (context) LOCK_CONTEXT (context); if (callback_funcs != &g_source_callback_funcs) { TRACE (GLIB_SOURCE_SET_CALLBACK_INDIRECT (source, callback_data, callback_funcs->ref, callback_funcs->unref, callback_funcs->get)); } old_cb_data = source->callback_data; old_cb_funcs = source->callback_funcs; source->callback_data = callback_data; source->callback_funcs = callback_funcs; if (context) { UNLOCK_CONTEXT (context); g_main_context_unref (context); } if (old_cb_funcs) old_cb_funcs->unref (old_cb_data); } /** * g_source_set_callback: * @source: the source * @func: a callback function * @data: the data to pass to callback function * @notify: (nullable): a function to call when @data is no longer in use * * Sets the callback function for a source. The callback for a source is * called from the source’s dispatch function. * * The exact type of @func depends on the type of source; ie. you * should not count on @func being called with @data as its first * parameter. Cast @func with [func@GLib.SOURCE_FUNC] to avoid warnings about * incompatible function types. * * See [main loop memory management](main-loop.html#memory-management-of-sources) for details * on how to handle memory management of @data. * * Typically, you won’t use this function. Instead use functions specific * to the type of source you are using, such as [func@GLib.idle_add] or * [func@GLib.timeout_add]. * * It is safe to call this function multiple times on a source which has already * been attached to a context. The changes will take effect for the next time * the source is dispatched after this call returns. * * Note that [method@GLib.Source.destroy] for a currently attached source has the effect * of also unsetting the callback. **/ void g_source_set_callback (GSource *source, GSourceFunc func, gpointer data, GDestroyNotify notify) { GSourceCallback *new_callback; g_return_if_fail (source != NULL); g_return_if_fail (g_atomic_int_get (&source->ref_count) > 0); TRACE (GLIB_SOURCE_SET_CALLBACK (source, func, data, notify)); new_callback = g_new (GSourceCallback, 1); new_callback->ref_count = 1; new_callback->func = func; new_callback->data = data; new_callback->notify = notify; g_source_set_callback_indirect (source, new_callback, &g_source_callback_funcs); } /** * g_source_set_funcs: * @source: a source * @funcs: the new source functions * * Sets the source functions of an unattached source. * * These can be used to override the default implementations for the type * of @source. * * Since: 2.12 */ void g_source_set_funcs (GSource *source, GSourceFuncs *funcs) { g_return_if_fail (source != NULL); g_return_if_fail (source->context == NULL); g_return_if_fail (g_atomic_int_get (&source->ref_count) > 0); g_return_if_fail (funcs != NULL); source->source_funcs = funcs; } static void g_source_set_priority_unlocked (GSource *source, GMainContext *context, gint priority) { GSList *tmp_list; g_return_if_fail (source->priv->parent_source == NULL || source->priv->parent_source->priority == priority); TRACE (GLIB_SOURCE_SET_PRIORITY (source, context, priority)); if (context) { /* Remove the source from the context's source and then * add it back after so it is sorted in the correct place */ source_remove_from_context (source, context); } source->priority = priority; if (context) { source_add_to_context (source, context); if (!SOURCE_BLOCKED (source)) { tmp_list = source->poll_fds; while (tmp_list) { g_main_context_remove_poll_unlocked (context, tmp_list->data); g_main_context_add_poll_unlocked (context, priority, tmp_list->data); tmp_list = tmp_list->next; } for (tmp_list = source->priv->fds; tmp_list; tmp_list = tmp_list->next) { g_main_context_remove_poll_unlocked (context, tmp_list->data); g_main_context_add_poll_unlocked (context, priority, tmp_list->data); } } } if (source->priv->child_sources) { tmp_list = source->priv->child_sources; while (tmp_list) { g_source_set_priority_unlocked (tmp_list->data, context, priority); tmp_list = tmp_list->next; } } } /** * g_source_set_priority: * @source: a source * @priority: the new priority * * Sets the priority of a source. * * While the main loop is being run, a * source will be dispatched if it is ready to be dispatched and no * sources at a higher (numerically smaller) priority are ready to be * dispatched. * * A child source always has the same priority as its parent. It is not * permitted to change the priority of a source once it has been added * as a child of another source. **/ void g_source_set_priority (GSource *source, gint priority) { GMainContext *context; g_return_if_fail (source != NULL); g_return_if_fail (g_atomic_int_get (&source->ref_count) > 0); g_return_if_fail (source->priv->parent_source == NULL); context = source_dup_main_context (source); if (context) LOCK_CONTEXT (context); g_source_set_priority_unlocked (source, context, priority); if (context) { UNLOCK_CONTEXT (context); g_main_context_unref (context); } } /** * g_source_get_priority: * @source: a source * * Gets the priority of a source. * * Returns: the priority of the source **/ gint g_source_get_priority (GSource *source) { g_return_val_if_fail (source != NULL, 0); g_return_val_if_fail (g_atomic_int_get (&source->ref_count) > 0, 0); return source->priority; } /** * g_source_set_ready_time: * @source: a source * @ready_time: the monotonic time at which the source will be ready; * `0` for ‘immediately’, `-1` for ‘never’ * * Sets a source to be dispatched when the given monotonic time is * reached (or passed). * * If the monotonic time is in the past (as it * always will be if @ready_time is `0`) then the source will be * dispatched immediately. * * If @ready_time is `-1` then the source is never woken up on the basis * of the passage of time. * * Dispatching the source does not reset the ready time. You should do * so yourself, from the source dispatch function. * * Note that if you have a pair of sources where the ready time of one * suggests that it will be delivered first but the priority for the * other suggests that it would be delivered first, and the ready time * for both sources is reached during the same main context iteration, * then the order of dispatch is undefined. * * It is a no-op to call this function on a [struct@GLib.Source] which has * already been destroyed with [method@GLib.Source.destroy]. * * This API is only intended to be used by implementations of [struct@GLib.Source]. * Do not call this API on a [struct@GLib.Source] that you did not create. * * Since: 2.36 **/ void g_source_set_ready_time (GSource *source, gint64 ready_time) { GMainContext *context; g_return_if_fail (source != NULL); g_return_if_fail (g_atomic_int_get (&source->ref_count) > 0); context = source_dup_main_context (source); if (context) LOCK_CONTEXT (context); if (source->priv->ready_time == ready_time) { if (context) { UNLOCK_CONTEXT (context); g_main_context_unref (context); } return; } source->priv->ready_time = ready_time; TRACE (GLIB_SOURCE_SET_READY_TIME (source, ready_time)); if (context) { /* Quite likely that we need to change the timeout on the poll */ if (!SOURCE_BLOCKED (source)) g_wakeup_signal (context->wakeup); UNLOCK_CONTEXT (context); g_main_context_unref (context); } } /** * g_source_get_ready_time: * @source: a source * * Gets the ‘ready time’ of @source, as set by * [method@GLib.Source.set_ready_time]. * * Any time before or equal to the current monotonic time (including zero) * is an indication that the source will fire immediately. * * Returns: the monotonic ready time, `-1` for ‘never’ **/ gint64 g_source_get_ready_time (GSource *source) { g_return_val_if_fail (source != NULL, -1); g_return_val_if_fail (g_atomic_int_get (&source->ref_count) > 0, -1); return source->priv->ready_time; } /** * g_source_set_can_recurse: * @source: a source * @can_recurse: whether recursion is allowed for this source * * Sets whether a source can be called recursively. * * If @can_recurse is true, then while the source is being dispatched then this * source will be processed normally. Otherwise, all processing of this * source is blocked until the dispatch function returns. **/ void g_source_set_can_recurse (GSource *source, gboolean can_recurse) { GMainContext *context; g_return_if_fail (source != NULL); g_return_if_fail (g_atomic_int_get (&source->ref_count) > 0); context = source_dup_main_context (source); if (context) LOCK_CONTEXT (context); if (can_recurse) g_atomic_int_or (&source->flags, G_SOURCE_CAN_RECURSE); else g_atomic_int_and (&source->flags, ~G_SOURCE_CAN_RECURSE); if (context) { UNLOCK_CONTEXT (context); g_main_context_unref (context); } } /** * g_source_get_can_recurse: * @source: a source * * Checks whether a source is allowed to be called recursively. * * See [method@GLib.Source.set_can_recurse]. * * Returns: whether recursion is allowed **/ gboolean g_source_get_can_recurse (GSource *source) { g_return_val_if_fail (source != NULL, FALSE); g_return_val_if_fail (g_atomic_int_get (&source->ref_count) > 0, FALSE); return (g_atomic_int_get (&source->flags) & G_SOURCE_CAN_RECURSE) != 0; } static void g_source_set_name_full (GSource *source, const char *name, gboolean is_static) { GMainContext *context; g_return_if_fail (source != NULL); g_return_if_fail (g_atomic_int_get (&source->ref_count) > 0); context = source_dup_main_context (source); if (context) LOCK_CONTEXT (context); TRACE (GLIB_SOURCE_SET_NAME (source, name)); /* setting back to NULL is allowed, just because it's * weird if get_name can return NULL but you can't * set that. */ if (!source->priv->static_name) g_free (source->name); if (is_static) source->name = (char *)name; else source->name = g_strdup (name); source->priv->static_name = is_static; if (context) { UNLOCK_CONTEXT (context); g_main_context_unref (context); } } /** * g_source_set_name: * @source: a source * @name: debug name for the source * * Sets a name for the source, used in debugging and profiling. * * The name defaults to `NULL`. * * The source name should describe in a human-readable way * what the source does. For example, ‘X11 event queue’ * or ‘GTK repaint idle handler’. * * It is permitted to call this function multiple times, but is not * recommended due to the potential performance impact. For example, * one could change the name in the `check` function of a * [struct@GLib.SourceFuncs] to include details like the event type in the * source name. * * Use caution if changing the name while another thread may be * accessing it with [method@GLib.Source.get_name]; that function does not copy * the value, and changing the value will free it while the other thread * may be attempting to use it. * * Also see [method@GLib.Source.set_static_name]. * * Since: 2.26 **/ void g_source_set_name (GSource *source, const char *name) { g_source_set_name_full (source, name, FALSE); } /** * g_source_set_static_name: * @source: a source * @name: debug name for the source * * A variant of [method@GLib.Source.set_name] that does not * duplicate the @name, and can only be used with * string literals. * * Since: 2.70 */ void g_source_set_static_name (GSource *source, const char *name) { g_source_set_name_full (source, name, TRUE); } /** * g_source_get_name: * @source: a source * * Gets a name for the source, used in debugging and profiling. * * The * name may be `NULL` if it has never been set with [method@GLib.Source.set_name]. * * Returns: (nullable): the name of the source * Since: 2.26 **/ const char * g_source_get_name (GSource *source) { g_return_val_if_fail (source != NULL, NULL); g_return_val_if_fail (g_atomic_int_get (&source->ref_count) > 0, NULL); return source->name; } /** * g_source_set_name_by_id: * @tag: a source ID * @name: debug name for the source * * Sets the name of a source using its ID. * * This is a convenience utility to set source names from the return * value of [func@GLib.idle_add], [func@GLib.timeout_add], etc. * * It is a programmer error to attempt to set the name of a non-existent * source. * * More specifically: source IDs can be reissued after a source has been * destroyed and therefore it is never valid to use this function with a * source ID which may have already been removed. An example is when * scheduling an idle to run in another thread with [func@GLib.idle_add]: the * idle may already have run and been removed by the time this function * is called on its (now invalid) source ID. This source ID may have * been reissued, leading to the operation being performed against the * wrong source. * * Since: 2.26 **/ void g_source_set_name_by_id (guint tag, const char *name) { GSource *source; g_return_if_fail (tag > 0); source = g_main_context_find_source_by_id (NULL, tag); if (source == NULL) return; g_source_set_name (source, name); } /** * g_source_ref: * @source: a source * * Increases the reference count on a source by one. * * Returns: @source **/ GSource * g_source_ref (GSource *source) { int old_ref G_GNUC_UNUSED; g_return_val_if_fail (source != NULL, NULL); old_ref = g_atomic_int_add (&source->ref_count, 1); /* We allow ref_count == 0 here to allow the dispose function to resurrect * the GSource if needed */ g_return_val_if_fail (old_ref >= 0, NULL); return source; } /* g_source_unref() but possible to call within context lock */ static void g_source_unref_internal (GSource *source, GMainContext *context, gboolean have_lock) { gpointer old_cb_data = NULL; GSourceCallbackFuncs *old_cb_funcs = NULL; int old_ref; g_return_if_fail (source != NULL); old_ref = g_atomic_int_get (&source->ref_count); retry_beginning: if (old_ref > 1) { /* We have many references. If we can decrement the ref counter, we are done. */ if (!g_atomic_int_compare_and_exchange_full ((int *) &source->ref_count, old_ref, old_ref - 1, &old_ref)) goto retry_beginning; return; } g_return_if_fail (old_ref > 0); if (!have_lock && context) LOCK_CONTEXT (context); /* We are about to drop the last reference, there's not guarantee at this * point that another thread already changed the value at this point or * that is also entering the disposal phase, but there is no much we can do * and dropping the reference too early would be still risky since it could * lead to a preventive finalization. * So let's just get all the threads that reached this point to get in, while * the final check on whether is the case or not to continue with the * finalization will be done by a final unique atomic dec and test. */ if (old_ref == 1) { /* If there's a dispose function, call this first */ GSourceDisposeFunc dispose_func; if ((dispose_func = g_atomic_pointer_get (&source->priv->dispose))) { if (context) UNLOCK_CONTEXT (context); dispose_func (source); if (context) LOCK_CONTEXT (context); } /* At this point the source can have been revived by any of the threads * acting on it or it's really ready for being finalized. */ if (!g_atomic_int_compare_and_exchange_full ((int *) &source->ref_count, 1, 0, &old_ref)) { if (!have_lock && context) UNLOCK_CONTEXT (context); goto retry_beginning; } TRACE (GLIB_SOURCE_BEFORE_FREE (source, context, source->source_funcs->finalize)); old_cb_data = source->callback_data; old_cb_funcs = source->callback_funcs; source->callback_data = NULL; source->callback_funcs = NULL; if (context) { if (!SOURCE_DESTROYED (source)) g_warning (G_STRLOC ": ref_count == 0, but source was still attached to a context!"); source_remove_from_context (source, context); g_hash_table_remove (context->sources, &source->source_id); } if (source->source_funcs->finalize) { gint old_ref_count; /* Temporarily increase the ref count again so that GSource methods * can be called from finalize(). */ g_atomic_int_inc (&source->ref_count); if (context) UNLOCK_CONTEXT (context); source->source_funcs->finalize (source); if (context) LOCK_CONTEXT (context); old_ref_count = g_atomic_int_add (&source->ref_count, -1); g_warn_if_fail (old_ref_count == 1); } if (old_cb_funcs) { gint old_ref_count; /* Temporarily increase the ref count again so that GSource methods * can be called from callback_funcs.unref(). */ g_atomic_int_inc (&source->ref_count); if (context) UNLOCK_CONTEXT (context); old_cb_funcs->unref (old_cb_data); if (context) LOCK_CONTEXT (context); old_ref_count = g_atomic_int_add (&source->ref_count, -1); g_warn_if_fail (old_ref_count == 1); } if (!source->priv->static_name) g_free (source->name); source->name = NULL; g_slist_free (source->poll_fds); source->poll_fds = NULL; g_slist_free_full (source->priv->fds, g_free); while (source->priv->child_sources) { GSource *child_source = source->priv->child_sources->data; source->priv->child_sources = g_slist_remove (source->priv->child_sources, child_source); child_source->priv->parent_source = NULL; g_source_unref_internal (child_source, context, TRUE); } g_slice_free (GSourcePrivate, source->priv); source->priv = NULL; g_free (source); } if (!have_lock && context) UNLOCK_CONTEXT (context); } /** * g_source_unref: * @source: a source * * Decreases the reference count of a source by one. * * If the resulting reference count is zero the source and associated * memory will be destroyed. **/ void g_source_unref (GSource *source) { GMainContext *context; g_return_if_fail (source != NULL); /* refcount is checked inside g_source_unref_internal() */ context = source_dup_main_context (source); g_source_unref_internal (source, context, FALSE); if (context) g_main_context_unref (context); } /** * g_main_context_find_source_by_id: * @context: (nullable): a main context (if `NULL`, the global-default * main context will be used) * @source_id: the source ID, as returned by [method@GLib.Source.get_id] * * Finds a [struct@GLib.Source] given a pair of context and ID. * * It is a programmer error to attempt to look up a non-existent source. * * More specifically: source IDs can be reissued after a source has been * destroyed and therefore it is never valid to use this function with a * source ID which may have already been removed. An example is when * scheduling an idle to run in another thread with [func@GLib.idle_add]: the * idle may already have run and been removed by the time this function * is called on its (now invalid) source ID. This source ID may have * been reissued, leading to the operation being performed against the * wrong source. * * Returns: (transfer none): the source **/ GSource * g_main_context_find_source_by_id (GMainContext *context, guint source_id) { GSource *source = NULL; gconstpointer ptr; g_return_val_if_fail (source_id > 0, NULL); if (context == NULL) context = g_main_context_default (); LOCK_CONTEXT (context); ptr = g_hash_table_lookup (context->sources, &source_id); if (ptr) { source = G_CONTAINER_OF (ptr, GSource, source_id); if (SOURCE_DESTROYED (source)) source = NULL; } UNLOCK_CONTEXT (context); return source; } /** * g_main_context_find_source_by_funcs_user_data: * @context: (nullable): a main context (if `NULL`, the global-default * main context will be used). * @funcs: the @source_funcs passed to [ctor@GLib.Source.new] * @user_data: the user data from the callback * * Finds a source with the given source functions and user data. * * If multiple sources exist with the same source function and user data, * the first one found will be returned. * * Returns: (transfer none) (nullable): the source, if one was found, * otherwise `NULL` **/ GSource * g_main_context_find_source_by_funcs_user_data (GMainContext *context, GSourceFuncs *funcs, gpointer user_data) { GSourceIter iter; GSource *source; g_return_val_if_fail (funcs != NULL, NULL); if (context == NULL) context = g_main_context_default (); LOCK_CONTEXT (context); g_source_iter_init (&iter, context, FALSE); while (g_source_iter_next (&iter, &source)) { if (!SOURCE_DESTROYED (source) && source->source_funcs == funcs && source->callback_funcs) { GSourceFunc callback; gpointer callback_data; source->callback_funcs->get (source->callback_data, source, &callback, &callback_data); if (callback_data == user_data) break; } } g_source_iter_clear (&iter); UNLOCK_CONTEXT (context); return source; } /** * g_main_context_find_source_by_user_data: * @context: (nullable): a main context (if `NULL`, the global-default * main context will be used) * @user_data: the user_data for the callback * * Finds a source with the given user data for the callback. * * If multiple sources exist with the same user data, the first * one found will be returned. * * Returns: (transfer none) (nullable): the source, if one was found, * otherwise `NULL` **/ GSource * g_main_context_find_source_by_user_data (GMainContext *context, gpointer user_data) { GSourceIter iter; GSource *source; if (context == NULL) context = g_main_context_default (); LOCK_CONTEXT (context); g_source_iter_init (&iter, context, FALSE); while (g_source_iter_next (&iter, &source)) { if (!SOURCE_DESTROYED (source) && source->callback_funcs) { GSourceFunc callback; gpointer callback_data = NULL; source->callback_funcs->get (source->callback_data, source, &callback, &callback_data); if (callback_data == user_data) break; } } g_source_iter_clear (&iter); UNLOCK_CONTEXT (context); return source; } /** * g_source_remove: * @tag: the ID of the source to remove. * * Removes the source with the given ID from the default main context. * * You must * use [method@GLib.Source.destroy] for sources added to a non-default main context. * * The ID of a [struct@GLib.Source] is given by [method@GLib.Source.get_id], or will be * returned by the functions [method@GLib.Source.attach], [func@GLib.idle_add], * [func@GLib.idle_add_full], [func@GLib.timeout_add], * [func@GLib.timeout_add_full], [func@GLib.child_watch_add], * [func@GLib.child_watch_add_full], [func@GLib.io_add_watch], and * [func@GLib.io_add_watch_full]. * * It is a programmer error to attempt to remove a non-existent source. * * More specifically: source IDs can be reissued after a source has been * destroyed and therefore it is never valid to use this function with a * source ID which may have already been removed. An example is when * scheduling an idle to run in another thread with [func@GLib.idle_add]: the * idle may already have run and been removed by the time this function * is called on its (now invalid) source ID. This source ID may have * been reissued, leading to the operation being performed against the * wrong source. * * Returns: true if the source was found and removed, false otherwise **/ gboolean g_source_remove (guint tag) { GSource *source; g_return_val_if_fail (tag > 0, FALSE); source = g_main_context_find_source_by_id (NULL, tag); if (source) g_source_destroy (source); else g_critical ("Source ID %u was not found when attempting to remove it", tag); return source != NULL; } /** * g_source_remove_by_user_data: * @user_data: the user_data for the callback * * Removes a source from the default main loop context given the user * data for the callback. * * If multiple sources exist with the same user data, only one will be destroyed. * * Returns: true if a source was found and removed, false otherwise **/ gboolean g_source_remove_by_user_data (gpointer user_data) { GSource *source; source = g_main_context_find_source_by_user_data (NULL, user_data); if (source) { g_source_destroy (source); return TRUE; } else return FALSE; } /** * g_source_remove_by_funcs_user_data: * @funcs: the @source_funcs passed to [ctor@GLib.Source.new] * @user_data: the user data for the callback * * Removes a source from the default main loop context given the * source functions and user data. * * If multiple sources exist with the same source functions and user data, only * one will be destroyed. * * Returns: true if a source was found and removed, false otherwise **/ gboolean g_source_remove_by_funcs_user_data (GSourceFuncs *funcs, gpointer user_data) { GSource *source; g_return_val_if_fail (funcs != NULL, FALSE); source = g_main_context_find_source_by_funcs_user_data (NULL, funcs, user_data); if (source) { g_source_destroy (source); return TRUE; } else return FALSE; } /** * g_clear_handle_id: (skip) * @tag_ptr: (not nullable): a pointer to the handler ID * @clear_func: (not nullable): the function to call to clear the handler * * Clears a numeric handler, such as a [struct@GLib.Source] ID. * * The @tag_ptr must be a valid pointer to the variable holding the handler. * * If the ID is zero then this function does nothing. * Otherwise, @clear_func is called with the ID as a parameter, and the tag is * set to zero. * * A macro is also included that allows this function to be used without * pointer casts. * * Since: 2.56 */ #undef g_clear_handle_id void g_clear_handle_id (guint *tag_ptr, GClearHandleFunc clear_func) { guint _handle_id; _handle_id = *tag_ptr; if (_handle_id > 0) { *tag_ptr = 0; clear_func (_handle_id); } } #ifdef G_OS_UNIX /** * g_source_add_unix_fd: * @source: a source * @fd: the file descriptor to monitor * @events: an event mask * * Monitors @fd for the IO events in @events. * * The tag returned by this function can be used to remove or modify the * monitoring of the @fd using [method@GLib.Source.remove_unix_fd] or * [method@GLib.Source.modify_unix_fd]. * * It is not necessary to remove the file descriptor before destroying the * source; it will be cleaned up automatically. * * This API is only intended to be used by implementations of [struct@GLib.Source]. * Do not call this API on a [struct@GLib.Source] that you did not create. * * As the name suggests, this function is not available on Windows. * * Returns: (not nullable): an opaque tag * Since: 2.36 **/ gpointer g_source_add_unix_fd (GSource *source, gint fd, GIOCondition events) { GMainContext *context; GPollFD *poll_fd; g_return_val_if_fail (source != NULL, NULL); g_return_val_if_fail (g_atomic_int_get (&source->ref_count) > 0, NULL); g_return_val_if_fail (!SOURCE_DESTROYED (source), NULL); poll_fd = g_new (GPollFD, 1); poll_fd->fd = fd; poll_fd->events = events; poll_fd->revents = 0; context = source_dup_main_context (source); if (context) LOCK_CONTEXT (context); source->priv->fds = g_slist_prepend (source->priv->fds, poll_fd); if (context) { if (!SOURCE_BLOCKED (source)) g_main_context_add_poll_unlocked (context, source->priority, poll_fd); UNLOCK_CONTEXT (context); g_main_context_unref (context); } return poll_fd; } /** * g_source_modify_unix_fd: * @source: a source * @tag: (not nullable): the tag from [method@GLib.Source.add_unix_fd] * @new_events: the new event mask to watch * * Updates the event mask to watch for the file descriptor identified by @tag. * * The @tag is the tag returned from [method@GLib.Source.add_unix_fd]. * * If you want to remove a file descriptor, don’t set its event mask to zero. * Instead, call [method@GLib.Source.remove_unix_fd]. * * This API is only intended to be used by implementations of [struct@GLib.Source]. * Do not call this API on a [struct@GLib.Source] that you did not create. * * As the name suggests, this function is not available on Windows. * * Since: 2.36 **/ void g_source_modify_unix_fd (GSource *source, gpointer tag, GIOCondition new_events) { GMainContext *context; GPollFD *poll_fd; g_return_if_fail (source != NULL); g_return_if_fail (g_atomic_int_get (&source->ref_count) > 0); g_return_if_fail (g_slist_find (source->priv->fds, tag)); context = source_dup_main_context (source); poll_fd = tag; poll_fd->events = new_events; if (context) { g_main_context_wakeup (context); g_main_context_unref (context); } } /** * g_source_remove_unix_fd: * @source: a source * @tag: (not nullable): the tag from [method@GLib.Source.add_unix_fd] * * Reverses the effect of a previous call to [method@GLib.Source.add_unix_fd]. * * You only need to call this if you want to remove a file descriptor from being * watched while keeping the same source around. In the normal case you * will just want to destroy the source. * * This API is only intended to be used by implementations of [struct@GLib.Source]. * Do not call this API on a [struct@GLib.Source] that you did not create. * * As the name suggests, this function is not available on Windows. * * Since: 2.36 **/ void g_source_remove_unix_fd (GSource *source, gpointer tag) { GMainContext *context; GPollFD *poll_fd; g_return_if_fail (source != NULL); g_return_if_fail (g_atomic_int_get (&source->ref_count) > 0); g_return_if_fail (g_slist_find (source->priv->fds, tag)); context = source_dup_main_context (source); poll_fd = tag; if (context) LOCK_CONTEXT (context); source->priv->fds = g_slist_remove (source->priv->fds, poll_fd); if (context) { if (!SOURCE_BLOCKED (source)) g_main_context_remove_poll_unlocked (context, poll_fd); UNLOCK_CONTEXT (context); g_main_context_unref (context); } g_free (poll_fd); } /** * g_source_query_unix_fd: * @source: a source * @tag: (not nullable): the tag from [method@GLib.Source.add_unix_fd] * * Queries the events reported for the file descriptor corresponding to @tag * on @source during the last poll. * * The return value of this function is only defined when the function * is called from the check or dispatch functions for @source. * * This API is only intended to be used by implementations of [struct@GLib.Source]. * Do not call this API on a [struct@GLib.Source] that you did not create. * * As the name suggests, this function is not available on Windows. * * Returns: the conditions reported on the file descriptor * Since: 2.36 **/ GIOCondition g_source_query_unix_fd (GSource *source, gpointer tag) { GPollFD *poll_fd; g_return_val_if_fail (source != NULL, 0); g_return_val_if_fail (g_atomic_int_get (&source->ref_count) > 0, 0); g_return_val_if_fail (g_slist_find (source->priv->fds, tag), 0); poll_fd = tag; return poll_fd->revents; } #endif /* G_OS_UNIX */ /** * g_get_current_time: * @result: [struct@GLib.TimeVal] structure in which to store current time * * Queries the system wall-clock time. * * This is equivalent to the UNIX [`gettimeofday()`](man:gettimeofday(2)) * function, but portable. * * You may find [func@GLib.get_real_time] to be more convenient. * * Deprecated: 2.62: [struct@GLib.TimeVal] is not year-2038-safe. Use * [func@GLib.get_real_time] instead. **/ G_GNUC_BEGIN_IGNORE_DEPRECATIONS void g_get_current_time (GTimeVal *result) { gint64 tv; g_return_if_fail (result != NULL); tv = g_get_real_time (); result->tv_sec = tv / 1000000; result->tv_usec = tv % 1000000; } G_GNUC_END_IGNORE_DEPRECATIONS /** * g_get_real_time: * * Queries the system wall-clock time. * * This is equivalent to the UNIX [`gettimeofday()`](man:gettimeofday(2)) * function, but portable. * * You should only use this call if you are actually interested in the real * wall-clock time. [func@GLib.get_monotonic_time] is probably more useful for * measuring intervals. * * Returns: the number of microseconds since * [January 1, 1970 UTC](https://en.wikipedia.org/wiki/Unix_time) * Since: 2.28 **/ gint64 g_get_real_time (void) { #ifndef G_OS_WIN32 struct timeval r; /* this is required on alpha, there the timeval structs are ints * not longs and a cast only would fail horribly */ gettimeofday (&r, NULL); return (((gint64) r.tv_sec) * 1000000) + r.tv_usec; #else FILETIME ft; guint64 time64; GetSystemTimeAsFileTime (&ft); memmove (&time64, &ft, sizeof (FILETIME)); /* Convert from 100s of nanoseconds since 1601-01-01 * to Unix epoch. This is Y2038 safe. */ time64 -= G_GINT64_CONSTANT (116444736000000000); time64 /= 10; return time64; #endif } /** * g_get_monotonic_time: * * Queries the system monotonic time. * * The monotonic clock will always increase and doesn’t suffer * discontinuities when the user (or NTP) changes the system time. It * may or may not continue to tick during times where the machine is * suspended. * * We try to use the clock that corresponds as closely as possible to * the passage of time as measured by system calls such as * [`poll()`](man:poll(2)) but it * may not always be possible to do this. * * Returns: the monotonic time, in microseconds * Since: 2.28 **/ #if defined (G_OS_WIN32) /* NOTE: * time_usec = ticks_since_boot * usec_per_sec / ticks_per_sec * * Doing (ticks_since_boot * usec_per_sec) before the division can overflow 64 bits * (ticks_since_boot / ticks_per_sec) and then multiply would not be accurate enough. * So for now we calculate (usec_per_sec / ticks_per_sec) and use floating point */ static gdouble g_monotonic_usec_per_tick = 0; void g_clock_win32_init (void) { LARGE_INTEGER freq; if (!QueryPerformanceFrequency (&freq) || freq.QuadPart == 0) { /* The documentation says that this should never happen */ g_assert_not_reached (); return; } g_monotonic_usec_per_tick = (gdouble)G_USEC_PER_SEC / freq.QuadPart; } gint64 g_get_monotonic_time (void) { if (G_LIKELY (g_monotonic_usec_per_tick != 0)) { LARGE_INTEGER ticks; if (QueryPerformanceCounter (&ticks)) return (gint64)(ticks.QuadPart * g_monotonic_usec_per_tick); g_warning ("QueryPerformanceCounter Failed (%lu)", GetLastError ()); g_monotonic_usec_per_tick = 0; } return 0; } #elif defined(HAVE_MACH_MACH_TIME_H) /* Mac OS */ gint64 g_get_monotonic_time (void) { mach_timebase_info_data_t timebase_info; guint64 val; /* we get nanoseconds from mach_absolute_time() using timebase_info */ mach_timebase_info (&timebase_info); val = mach_absolute_time (); if (timebase_info.numer != timebase_info.denom) { #ifdef HAVE_UINT128_T val = ((__uint128_t) val * (__uint128_t) timebase_info.numer) / timebase_info.denom / 1000; #else guint64 t_high, t_low; guint64 result_high, result_low; /* 64 bit x 32 bit / 32 bit with 96-bit intermediate * algorithm lifted from qemu */ t_low = (val & 0xffffffffLL) * (guint64) timebase_info.numer; t_high = (val >> 32) * (guint64) timebase_info.numer; t_high += (t_low >> 32); result_high = t_high / (guint64) timebase_info.denom; result_low = (((t_high % (guint64) timebase_info.denom) << 32) + (t_low & 0xffffffff)) / (guint64) timebase_info.denom; val = ((result_high << 32) | result_low) / 1000; #endif } else { /* nanoseconds to microseconds */ val = val / 1000; } return val; } #else gint64 g_get_monotonic_time (void) { struct timespec ts; gint result; result = clock_gettime (CLOCK_MONOTONIC, &ts); if G_UNLIKELY (result != 0) g_error ("GLib requires working CLOCK_MONOTONIC"); return (((gint64) ts.tv_sec) * 1000000) + (ts.tv_nsec / 1000); } #endif static void g_main_dispatch_free (gpointer dispatch) { g_free (dispatch); } /* Running the main loop */ static GMainDispatch * get_dispatch (void) { static GPrivate depth_private = G_PRIVATE_INIT (g_main_dispatch_free); GMainDispatch *dispatch; dispatch = g_private_get (&depth_private); if (!dispatch) dispatch = g_private_set_alloc0 (&depth_private, sizeof (GMainDispatch)); return dispatch; } /** * g_main_depth: * * Returns the depth of the stack of calls to * [method@GLib.MainContext.dispatch] on any #GMainContext in the current thread. * * That is, when called from the top level, it gives `0`. When * called from within a callback from [method@GLib.MainContext.iteration] * (or [method@GLib.MainLoop.run], etc.) it returns `1`. When called from within * a callback to a recursive call to [method@GLib.MainContext.iteration], * it returns `2`. And so forth. * * This function is useful in a situation like the following: * Imagine an extremely simple ‘garbage collected’ system. * * ```c * static GList *free_list; * * gpointer * allocate_memory (gsize size) * { * gpointer result = g_malloc (size); * free_list = g_list_prepend (free_list, result); * return result; * } * * void * free_allocated_memory (void) * { * GList *l; * for (l = free_list; l; l = l->next); * g_free (l->data); * g_list_free (free_list); * free_list = NULL; * } * * [...] * * while (TRUE); * { * g_main_context_iteration (NULL, TRUE); * free_allocated_memory(); * } * ``` * * This works from an application, however, if you want to do the same * thing from a library, it gets more difficult, since you no longer * control the main loop. You might think you can simply use an idle * function to make the call to `free_allocated_memory()`, but that * doesn’t work, since the idle function could be called from a * recursive callback. This can be fixed by using [func@GLib.main_depth] * * ```c * gpointer * allocate_memory (gsize size) * { * FreeListBlock *block = g_new (FreeListBlock, 1); * block->mem = g_malloc (size); * block->depth = g_main_depth (); * free_list = g_list_prepend (free_list, block); * return block->mem; * } * * void * free_allocated_memory (void) * { * GList *l; * * int depth = g_main_depth (); * for (l = free_list; l; ); * { * GList *next = l->next; * FreeListBlock *block = l->data; * if (block->depth > depth) * { * g_free (block->mem); * g_free (block); * free_list = g_list_delete_link (free_list, l); * } * * l = next; * } * } * ``` * * There is a temptation to use [func@GLib.main_depth] to solve * problems with reentrancy. For instance, while waiting for data * to be received from the network in response to a menu item, * the menu item might be selected again. It might seem that * one could make the menu item’s callback return immediately * and do nothing if [func@GLib.main_depth] returns a value greater than 1. * However, this should be avoided since the user then sees selecting * the menu item do nothing. Furthermore, you’ll find yourself adding * these checks all over your code, since there are doubtless many, * many things that the user could do. Instead, you can use the * following techniques: * * 1. Use `gtk_widget_set_sensitive()` or modal dialogs to prevent * the user from interacting with elements while the main * loop is recursing. * * 2. Avoid main loop recursion in situations where you can’t handle * arbitrary callbacks. Instead, structure your code so that you * simply return to the main loop and then get called again when * there is more work to do. * * Returns: the main loop recursion level in the current thread */ int g_main_depth (void) { GMainDispatch *dispatch = get_dispatch (); return dispatch->depth; } /** * g_main_current_source: * * Returns the currently firing source for this thread. * * Returns: (transfer none) (nullable): the currently firing source, or `NULL` * if none is firing * Since: 2.12 */ GSource * g_main_current_source (void) { GMainDispatch *dispatch = get_dispatch (); return dispatch->source; } /** * g_source_is_destroyed: * @source: a source * * Returns whether @source has been destroyed. * * This is important when you operate upon your objects * from within idle handlers, but may have freed the object * before the dispatch of your idle handler. * * ```c * static gboolean * idle_callback (gpointer data) * { * SomeWidget *self = data; * * g_mutex_lock (&self->idle_id_mutex); * // do stuff with self * self->idle_id = 0; * g_mutex_unlock (&self->idle_id_mutex); * * return G_SOURCE_REMOVE; * } * * static void * some_widget_do_stuff_later (SomeWidget *self) * { * g_mutex_lock (&self->idle_id_mutex); * self->idle_id = g_idle_add (idle_callback, self); * g_mutex_unlock (&self->idle_id_mutex); * } * * static void * some_widget_init (SomeWidget *self) * { * g_mutex_init (&self->idle_id_mutex); * * // ... * } * * static void * some_widget_finalize (GObject *object) * { * SomeWidget *self = SOME_WIDGET (object); * * if (self->idle_id) * g_source_remove (self->idle_id); * * g_mutex_clear (&self->idle_id_mutex); * * G_OBJECT_CLASS (parent_class)->finalize (object); * } * ``` * * This will fail in a multi-threaded application if the * widget is destroyed before the idle handler fires due * to the use after free in the callback. A solution, to * this particular problem, is to check to if the source * has already been destroy within the callback. * * ```c * static gboolean * idle_callback (gpointer data) * { * SomeWidget *self = data; * * g_mutex_lock (&self->idle_id_mutex); * if (!g_source_is_destroyed (g_main_current_source ())) * { * // do stuff with self * } * g_mutex_unlock (&self->idle_id_mutex); * * return FALSE; * } * ``` * * Calls to this function from a thread other than the one acquired by the * [struct@GLib.MainContext] the [struct@GLib.Source] is attached to are typically * redundant, as the source could be destroyed immediately after this function * returns. However, once a source is destroyed it cannot be un-destroyed, so * this function can be used for opportunistic checks from any thread. * * Returns: true if the source has been destroyed, false otherwise * Since: 2.12 */ gboolean g_source_is_destroyed (GSource *source) { g_return_val_if_fail (source != NULL, TRUE); g_return_val_if_fail (g_atomic_int_get (&source->ref_count) > 0, TRUE); return SOURCE_DESTROYED (source); } /* Temporarily remove all this source's file descriptors from the * poll(), so that if data comes available for one of the file descriptors * we don't continually spin in the poll() */ /* HOLDS: source->context's lock */ static void block_source (GSource *source, GMainContext *context) { GSList *tmp_list; g_return_if_fail (!SOURCE_BLOCKED (source)); g_atomic_int_or (&source->flags, G_SOURCE_BLOCKED); if (context) { tmp_list = source->poll_fds; while (tmp_list) { g_main_context_remove_poll_unlocked (context, tmp_list->data); tmp_list = tmp_list->next; } for (tmp_list = source->priv->fds; tmp_list; tmp_list = tmp_list->next) g_main_context_remove_poll_unlocked (context, tmp_list->data); } if (source->priv && source->priv->child_sources) { tmp_list = source->priv->child_sources; while (tmp_list) { block_source (tmp_list->data, context); tmp_list = tmp_list->next; } } } /* HOLDS: source->context's lock */ static void unblock_source (GSource *source, GMainContext *context) { GSList *tmp_list; g_return_if_fail (SOURCE_BLOCKED (source)); /* Source already unblocked */ g_return_if_fail (!SOURCE_DESTROYED (source)); g_atomic_int_and (&source->flags, ~G_SOURCE_BLOCKED); tmp_list = source->poll_fds; while (tmp_list) { g_main_context_add_poll_unlocked (context, source->priority, tmp_list->data); tmp_list = tmp_list->next; } for (tmp_list = source->priv->fds; tmp_list; tmp_list = tmp_list->next) g_main_context_add_poll_unlocked (context, source->priority, tmp_list->data); if (source->priv && source->priv->child_sources) { tmp_list = source->priv->child_sources; while (tmp_list) { unblock_source (tmp_list->data, context); tmp_list = tmp_list->next; } } } /* HOLDS: context's lock */ static void g_main_dispatch (GMainContext *context) { GMainDispatch *current = get_dispatch (); guint i; for (i = 0; i < context->pending_dispatches->len; i++) { GSource *source = context->pending_dispatches->pdata[i]; context->pending_dispatches->pdata[i] = NULL; g_assert (source); g_atomic_int_and (&source->flags, ~G_SOURCE_READY); if (!SOURCE_DESTROYED (source)) { gboolean was_in_call; gpointer user_data = NULL; GSourceFunc callback = NULL; GSourceCallbackFuncs *cb_funcs; gpointer cb_data; gboolean need_destroy; gboolean (*dispatch) (GSource *, GSourceFunc, gpointer); GSource *prev_source; gint64 begin_time_nsec G_GNUC_UNUSED; dispatch = source->source_funcs->dispatch; cb_funcs = source->callback_funcs; cb_data = source->callback_data; if (cb_funcs) cb_funcs->ref (cb_data); if ((g_atomic_int_get (&source->flags) & G_SOURCE_CAN_RECURSE) == 0) block_source (source, context); was_in_call = g_atomic_int_or (&source->flags, (GSourceFlags) G_HOOK_FLAG_IN_CALL) & G_HOOK_FLAG_IN_CALL; if (cb_funcs) cb_funcs->get (cb_data, source, &callback, &user_data); UNLOCK_CONTEXT (context); /* These operations are safe because 'current' is thread-local * and not modified from anywhere but this function. */ prev_source = current->source; current->source = source; current->depth++; begin_time_nsec = G_TRACE_CURRENT_TIME; TRACE (GLIB_MAIN_BEFORE_DISPATCH (g_source_get_name (source), source, dispatch, callback, user_data)); need_destroy = !(* dispatch) (source, callback, user_data); TRACE (GLIB_MAIN_AFTER_DISPATCH (g_source_get_name (source), source, dispatch, need_destroy)); g_trace_mark (begin_time_nsec, G_TRACE_CURRENT_TIME - begin_time_nsec, "GLib", "GSource.dispatch", "%s ⇒ %s", (g_source_get_name (source) != NULL) ? g_source_get_name (source) : "(unnamed)", need_destroy ? "destroy" : "keep"); current->source = prev_source; current->depth--; if (cb_funcs) cb_funcs->unref (cb_data); LOCK_CONTEXT (context); if (!was_in_call) g_atomic_int_and (&source->flags, ~G_HOOK_FLAG_IN_CALL); if (SOURCE_BLOCKED (source) && !SOURCE_DESTROYED (source)) unblock_source (source, context); /* Note: this depends on the fact that we can't switch * sources from one main context to another */ if (need_destroy && !SOURCE_DESTROYED (source)) { g_assert (source->context == context); g_source_destroy_internal (source, context, TRUE); } } g_source_unref_internal (source, context, TRUE); } g_ptr_array_set_size (context->pending_dispatches, 0); } /** * g_main_context_acquire: * @context: (nullable): a main context (if `NULL`, the global-default * main context will be used) * * Tries to become the owner of the specified context. * * If some other thread is the owner of the context, * returns false immediately. Ownership is properly * recursive: the owner can require ownership again * and will release ownership when [method@GLib.MainContext.release] * is called as many times as [method@GLib.MainContext.acquire]. * * You must be the owner of a context before you * can call [method@GLib.MainContext.prepare], [method@GLib.MainContext.query], * [method@GLib.MainContext.check], [method@GLib.MainContext.dispatch], * [method@GLib.MainContext.release]. * * Since 2.76 @context can be `NULL` to use the global-default * main context. * * Returns: true if this thread is now the owner of @context, false otherwise **/ gboolean g_main_context_acquire (GMainContext *context) { gboolean result = FALSE; if (context == NULL) context = g_main_context_default (); LOCK_CONTEXT (context); result = g_main_context_acquire_unlocked (context); UNLOCK_CONTEXT (context); return result; } static gboolean g_main_context_acquire_unlocked (GMainContext *context) { GThread *self = G_THREAD_SELF; if (!context->owner) { context->owner = self; g_assert (context->owner_count == 0); TRACE (GLIB_MAIN_CONTEXT_ACQUIRE (context, TRUE /* success */)); } if (context->owner == self) { context->owner_count++; return TRUE; } else { TRACE (GLIB_MAIN_CONTEXT_ACQUIRE (context, FALSE /* failure */)); return FALSE; } } /** * g_main_context_release: * @context: (nullable): a main context (if `NULL`, the global-default * main context will be used) * * Releases ownership of a context previously acquired by this thread * with [method@GLib.MainContext.acquire]. * * If the context was acquired multiple * times, the ownership will be released only when [method@GLib.MainContext.release] * is called as many times as it was acquired. * * You must have successfully acquired the context with * [method@GLib.MainContext.acquire] before you may call this function. **/ void g_main_context_release (GMainContext *context) { if (context == NULL) context = g_main_context_default (); LOCK_CONTEXT (context); g_main_context_release_unlocked (context); UNLOCK_CONTEXT (context); } static void g_main_context_release_unlocked (GMainContext *context) { /* NOTE: We should also have the following assert here: * g_return_if_fail (context->owner == G_THREAD_SELF); * However, this breaks NetworkManager, which has been (non-compliantly but * apparently safely) releasing a #GMainContext from a thread which didn’t * acquire it. * Breaking that would be quite disruptive, so we won’t do that now. However, * GLib reserves the right to add that assertion in future, if doing so would * allow for optimisations or refactorings. By that point, NetworkManager will * have to have reworked its use of #GMainContext. * * See: https://gitlab.gnome.org/GNOME/glib/-/merge_requests/3513 */ g_return_if_fail (context->owner_count > 0); context->owner_count--; if (context->owner_count == 0) { TRACE (GLIB_MAIN_CONTEXT_RELEASE (context)); context->owner = NULL; if (context->waiters) { GMainWaiter *waiter = context->waiters->data; gboolean loop_internal_waiter = (waiter->mutex == &context->mutex); context->waiters = g_slist_delete_link (context->waiters, context->waiters); if (!loop_internal_waiter) g_mutex_lock (waiter->mutex); g_cond_signal (waiter->cond); if (!loop_internal_waiter) g_mutex_unlock (waiter->mutex); } } } static gboolean g_main_context_wait_internal (GMainContext *context, GCond *cond, GMutex *mutex) { gboolean result = FALSE; GThread *self = G_THREAD_SELF; gboolean loop_internal_waiter; loop_internal_waiter = (mutex == &context->mutex); if (!loop_internal_waiter) LOCK_CONTEXT (context); if (context->owner && context->owner != self) { GMainWaiter waiter; waiter.cond = cond; waiter.mutex = mutex; context->waiters = g_slist_append (context->waiters, &waiter); if (!loop_internal_waiter) UNLOCK_CONTEXT (context); g_cond_wait (cond, mutex); if (!loop_internal_waiter) LOCK_CONTEXT (context); context->waiters = g_slist_remove (context->waiters, &waiter); } if (!context->owner) { context->owner = self; g_assert (context->owner_count == 0); } if (context->owner == self) { context->owner_count++; result = TRUE; } if (!loop_internal_waiter) UNLOCK_CONTEXT (context); return result; } /** * g_main_context_wait: * @context: (nullable): a main context (if `NULL`, the global-default * main context will be used) * @cond: a condition variable * @mutex: a mutex, currently held * * Tries to become the owner of the specified context, and waits on @cond if * another thread is the owner. * * This is the same as [method@GLib.MainContext.acquire], but if another thread * is the owner, atomically drop @mutex and wait on @cond until * that owner releases ownership or until @cond is signaled, then * try again (once) to become the owner. * * Returns: true if this thread is now the owner of @context, false otherwise * Deprecated: 2.58: Use [method@GLib.MainContext.is_owner] and separate * locking instead. */ gboolean g_main_context_wait (GMainContext *context, GCond *cond, GMutex *mutex) { if (context == NULL) context = g_main_context_default (); if (G_UNLIKELY (cond != &context->cond || mutex != &context->mutex)) { static gboolean warned; if (!warned) { g_critical ("WARNING!! g_main_context_wait() will be removed in a future release. " "If you see this message, please file a bug immediately."); warned = TRUE; } } return g_main_context_wait_internal (context, cond, mutex); } /** * g_main_context_prepare: * @context: (nullable): a main context (if `NULL`, the global-default * main context will be used) * @priority: (out) (optional): location to store priority of highest priority * source already ready * * Prepares to poll sources within a main loop. * * The resulting information * for polling is determined by calling [method@GLib.MainContext.query]. * * You must have successfully acquired the context with * [method@GLib.MainContext.acquire] before you may call this function. * * Returns: true if some source is ready to be dispatched prior to polling, * false otherwise **/ gboolean g_main_context_prepare (GMainContext *context, gint *priority) { gboolean ready; if (context == NULL) context = g_main_context_default (); LOCK_CONTEXT (context); ready = g_main_context_prepare_unlocked (context, priority); UNLOCK_CONTEXT (context); return ready; } static inline int round_timeout_to_msec (gint64 timeout_usec) { /* We need to round to milliseconds from our internal microseconds for * various external API and GPollFunc which requires milliseconds. * * However, we want to ensure a few invariants for this. * * Return == -1 if we have no timeout specified * Return == 0 if we don't want to block at all * Return > 0 if we have any timeout to avoid spinning the CPU * * This does cause jitter if the microsecond timeout is < 1000 usec * because that is beyond our precision. However, using ppoll() instead * of poll() (when available) avoids this jitter. */ if (timeout_usec == 0) return 0; if (timeout_usec > 0) { guint64 timeout_msec = (timeout_usec + 999) / 1000; return (int) MIN (timeout_msec, G_MAXINT); } return -1; } static inline gint64 extend_timeout_to_usec (int timeout_msec) { if (timeout_msec >= 0) return (gint64) timeout_msec * 1000; return -1; } static gboolean g_main_context_prepare_unlocked (GMainContext *context, gint *priority) { guint i; gint n_ready = 0; gint current_priority = G_MAXINT; GSource *source; GSourceIter iter; context->time_is_fresh = FALSE; if (context->in_check_or_prepare) { g_warning ("g_main_context_prepare() called recursively from within a source's check() or " "prepare() member."); return FALSE; } TRACE (GLIB_MAIN_CONTEXT_BEFORE_PREPARE (context)); #if 0 /* If recursing, finish up current dispatch, before starting over */ if (context->pending_dispatches) { if (dispatch) g_main_dispatch (context, ¤t_time); return TRUE; } #endif /* If recursing, clear list of pending dispatches */ for (i = 0; i < context->pending_dispatches->len; i++) { if (context->pending_dispatches->pdata[i]) g_source_unref_internal ((GSource *)context->pending_dispatches->pdata[i], context, TRUE); } g_ptr_array_set_size (context->pending_dispatches, 0); /* Prepare all sources */ context->timeout_usec = -1; g_source_iter_init (&iter, context, TRUE); while (g_source_iter_next (&iter, &source)) { gint64 source_timeout_usec = -1; if (SOURCE_DESTROYED (source) || SOURCE_BLOCKED (source)) continue; if ((n_ready > 0) && (source->priority > current_priority)) break; if (!(g_atomic_int_get (&source->flags) & G_SOURCE_READY)) { gboolean result; gboolean (* prepare) (GSource *source, gint *timeout); prepare = source->source_funcs->prepare; if (prepare) { gint64 begin_time_nsec G_GNUC_UNUSED; int source_timeout_msec = -1; context->in_check_or_prepare++; UNLOCK_CONTEXT (context); begin_time_nsec = G_TRACE_CURRENT_TIME; result = (*prepare) (source, &source_timeout_msec); TRACE (GLIB_MAIN_AFTER_PREPARE (source, prepare, source_timeout_msec)); source_timeout_usec = extend_timeout_to_usec (source_timeout_msec); g_trace_mark (begin_time_nsec, G_TRACE_CURRENT_TIME - begin_time_nsec, "GLib", "GSource.prepare", "%s ⇒ %s", (g_source_get_name (source) != NULL) ? g_source_get_name (source) : "(unnamed)", result ? "ready" : "unready"); LOCK_CONTEXT (context); context->in_check_or_prepare--; } else result = FALSE; if (result == FALSE && source->priv->ready_time != -1) { if (!context->time_is_fresh) { context->time = g_get_monotonic_time (); context->time_is_fresh = TRUE; } if (source->priv->ready_time <= context->time) { source_timeout_usec = 0; result = TRUE; } else if (source_timeout_usec < 0 || (source->priv->ready_time < context->time + source_timeout_usec)) { source_timeout_usec = MAX (0, source->priv->ready_time - context->time); } } if (result) { GSource *ready_source = source; while (ready_source) { g_atomic_int_or (&ready_source->flags, G_SOURCE_READY); ready_source = ready_source->priv->parent_source; } } } if (g_atomic_int_get (&source->flags) & G_SOURCE_READY) { n_ready++; current_priority = source->priority; context->timeout_usec = 0; } if (source_timeout_usec >= 0) { if (context->timeout_usec < 0) context->timeout_usec = source_timeout_usec; else context->timeout_usec = MIN (context->timeout_usec, source_timeout_usec); } } g_source_iter_clear (&iter); TRACE (GLIB_MAIN_CONTEXT_AFTER_PREPARE (context, current_priority, n_ready)); if (priority) *priority = current_priority; return (n_ready > 0); } /** * g_main_context_query: * @context: (nullable): a main context (if `NULL`, the global-default * main context will be used) * @max_priority: maximum priority source to check * @timeout_: (out): location to store timeout to be used in polling * @fds: (out caller-allocates) (array length=n_fds): location to * store [struct@GLib.PollFD] records that need to be polled * @n_fds: (in): length of @fds * * Determines information necessary to poll this main loop. * * You should * be careful to pass the resulting @fds array and its length @n_fds * as-is when calling [method@GLib.MainContext.check], as this function relies * on assumptions made when the array is filled. * * You must have successfully acquired the context with * [method@GLib.MainContext.acquire] before you may call this function. * * Returns: the number of records actually stored in @fds, * or, if more than @n_fds records need to be stored, the number * of records that need to be stored **/ gint g_main_context_query (GMainContext *context, gint max_priority, gint *timeout_msec, GPollFD *fds, gint n_fds) { gint64 timeout_usec; gint n_poll; if (context == NULL) context = g_main_context_default (); LOCK_CONTEXT (context); n_poll = g_main_context_query_unlocked (context, max_priority, &timeout_usec, fds, n_fds); UNLOCK_CONTEXT (context); if (timeout_msec != NULL) *timeout_msec = round_timeout_to_msec (timeout_usec); return n_poll; } static gint g_main_context_query_unlocked (GMainContext *context, gint max_priority, gint64 *timeout_usec, GPollFD *fds, gint n_fds) { gint n_poll; GPollRec *pollrec, *lastpollrec; gushort events; TRACE (GLIB_MAIN_CONTEXT_BEFORE_QUERY (context, max_priority)); /* fds is filled sequentially from poll_records. Since poll_records * are incrementally sorted by file descriptor identifier, fds will * also be incrementally sorted. */ n_poll = 0; lastpollrec = NULL; for (pollrec = context->poll_records; pollrec; pollrec = pollrec->next) { if (pollrec->priority > max_priority) continue; /* In direct contradiction to the Unix98 spec, IRIX runs into * difficulty if you pass in POLLERR, POLLHUP or POLLNVAL * flags in the events field of the pollfd while it should * just ignoring them. So we mask them out here. */ events = pollrec->fd->events & ~(G_IO_ERR|G_IO_HUP|G_IO_NVAL); /* This optimization --using the same GPollFD to poll for more * than one poll record-- relies on the poll records being * incrementally sorted. */ if (lastpollrec && pollrec->fd->fd == lastpollrec->fd->fd) { if (n_poll - 1 < n_fds) fds[n_poll - 1].events |= events; } else { if (n_poll < n_fds) { fds[n_poll].fd = pollrec->fd->fd; fds[n_poll].events = events; fds[n_poll].revents = 0; } n_poll++; } lastpollrec = pollrec; } context->poll_changed = FALSE; if (timeout_usec) { *timeout_usec = context->timeout_usec; if (*timeout_usec != 0) context->time_is_fresh = FALSE; } TRACE (GLIB_MAIN_CONTEXT_AFTER_QUERY (context, context->timeout_usec, fds, n_poll)); return n_poll; } /** * g_main_context_check: * @context: (nullable): a main context (if `NULL`, the global-default * main context will be used) * @max_priority: the maximum numerical priority of sources to check * @fds: (array length=n_fds): array of [struct@GLib.PollFD]s that was passed to * the last call to [method@GLib.MainContext.query] * @n_fds: return value of [method@GLib.MainContext.query] * * Passes the results of polling back to the main loop. * * You should be * careful to pass @fds and its length @n_fds as received from * [method@GLib.MainContext.query], as this functions relies on assumptions * on how @fds is filled. * * You must have successfully acquired the context with * [method@GLib.MainContext.acquire] before you may call this function. * * Since 2.76 @context can be `NULL` to use the global-default * main context. * * Returns: true if some sources are ready to be dispatched, false otherwise **/ gboolean g_main_context_check (GMainContext *context, gint max_priority, GPollFD *fds, gint n_fds) { gboolean ready; LOCK_CONTEXT (context); ready = g_main_context_check_unlocked (context, max_priority, fds, n_fds); UNLOCK_CONTEXT (context); return ready; } static gboolean g_main_context_check_unlocked (GMainContext *context, gint max_priority, GPollFD *fds, gint n_fds) { GSource *source; GSourceIter iter; GPollRec *pollrec; gint n_ready = 0; gint i; if (context == NULL) context = g_main_context_default (); if (context->in_check_or_prepare) { g_warning ("g_main_context_check() called recursively from within a source's check() or " "prepare() member."); return FALSE; } TRACE (GLIB_MAIN_CONTEXT_BEFORE_CHECK (context, max_priority, fds, n_fds)); for (i = 0; i < n_fds; i++) { if (fds[i].fd == context->wake_up_rec.fd) { if (fds[i].revents) { TRACE (GLIB_MAIN_CONTEXT_WAKEUP_ACKNOWLEDGE (context)); g_wakeup_acknowledge (context->wakeup); } break; } } /* If the set of poll file descriptors changed, bail out * and let the main loop rerun */ if (context->poll_changed) { TRACE (GLIB_MAIN_CONTEXT_AFTER_CHECK (context, 0)); return FALSE; } /* The linear iteration below relies on the assumption that both * poll records and the fds array are incrementally sorted by file * descriptor identifier. */ pollrec = context->poll_records; i = 0; while (pollrec && i < n_fds) { /* Make sure that fds is sorted by file descriptor identifier. */ g_assert (i <= 0 || fds[i - 1].fd < fds[i].fd); /* Skip until finding the first GPollRec matching the current GPollFD. */ while (pollrec && pollrec->fd->fd != fds[i].fd) pollrec = pollrec->next; /* Update all consecutive GPollRecs that match. */ while (pollrec && pollrec->fd->fd == fds[i].fd) { if (pollrec->priority <= max_priority) { pollrec->fd->revents = fds[i].revents & (pollrec->fd->events | G_IO_ERR | G_IO_HUP | G_IO_NVAL); } pollrec = pollrec->next; } /* Iterate to next GPollFD. */ i++; } g_source_iter_init (&iter, context, TRUE); while (g_source_iter_next (&iter, &source)) { if (SOURCE_DESTROYED (source) || SOURCE_BLOCKED (source)) continue; if ((n_ready > 0) && (source->priority > max_priority)) break; if (!(g_atomic_int_get (&source->flags) & G_SOURCE_READY)) { gboolean result; gboolean (* check) (GSource *source); check = source->source_funcs->check; if (check) { gint64 begin_time_nsec G_GNUC_UNUSED; /* If the check function is set, call it. */ context->in_check_or_prepare++; UNLOCK_CONTEXT (context); begin_time_nsec = G_TRACE_CURRENT_TIME; result = (* check) (source); TRACE (GLIB_MAIN_AFTER_CHECK (source, check, result)); g_trace_mark (begin_time_nsec, G_TRACE_CURRENT_TIME - begin_time_nsec, "GLib", "GSource.check", "%s ⇒ %s", (g_source_get_name (source) != NULL) ? g_source_get_name (source) : "(unnamed)", result ? "dispatch" : "ignore"); LOCK_CONTEXT (context); context->in_check_or_prepare--; } else result = FALSE; if (result == FALSE) { GSList *tmp_list; /* If not already explicitly flagged ready by ->check() * (or if we have no check) then we can still be ready if * any of our fds poll as ready. */ for (tmp_list = source->priv->fds; tmp_list; tmp_list = tmp_list->next) { GPollFD *pollfd = tmp_list->data; if (pollfd->revents) { result = TRUE; break; } } } if (result == FALSE && source->priv->ready_time != -1) { if (!context->time_is_fresh) { context->time = g_get_monotonic_time (); context->time_is_fresh = TRUE; } if (source->priv->ready_time <= context->time) result = TRUE; } if (result) { GSource *ready_source = source; while (ready_source) { g_atomic_int_or (&ready_source->flags, G_SOURCE_READY); ready_source = ready_source->priv->parent_source; } } } if (g_atomic_int_get (&source->flags) & G_SOURCE_READY) { g_source_ref (source); g_ptr_array_add (context->pending_dispatches, source); n_ready++; /* never dispatch sources with less priority than the first * one we choose to dispatch */ max_priority = source->priority; } } g_source_iter_clear (&iter); TRACE (GLIB_MAIN_CONTEXT_AFTER_CHECK (context, n_ready)); return n_ready > 0; } /** * g_main_context_dispatch: * @context: (nullable): a main context (if `NULL`, the global-default * main context will be used) * * Dispatches all pending sources. * * You must have successfully acquired the context with * [method@GLib.MainContext.acquire] before you may call this function. * * Since 2.76 @context can be `NULL` to use the global-default * main context. **/ void g_main_context_dispatch (GMainContext *context) { if (context == NULL) context = g_main_context_default (); LOCK_CONTEXT (context); g_main_context_dispatch_unlocked (context); UNLOCK_CONTEXT (context); } static void g_main_context_dispatch_unlocked (GMainContext *context) { TRACE (GLIB_MAIN_CONTEXT_BEFORE_DISPATCH (context)); if (context->pending_dispatches->len > 0) { g_main_dispatch (context); } TRACE (GLIB_MAIN_CONTEXT_AFTER_DISPATCH (context)); } /* HOLDS context lock */ static gboolean g_main_context_iterate_unlocked (GMainContext *context, gboolean block, gboolean dispatch, GThread *self) { gint max_priority = 0; gint64 timeout_usec; gboolean some_ready; gint nfds, allocated_nfds; GPollFD *fds = NULL; gint64 begin_time_nsec G_GNUC_UNUSED; begin_time_nsec = G_TRACE_CURRENT_TIME; if (!g_main_context_acquire_unlocked (context)) { gboolean got_ownership; if (!block) return FALSE; got_ownership = g_main_context_wait_internal (context, &context->cond, &context->mutex); if (!got_ownership) return FALSE; } if (!context->cached_poll_array) { context->cached_poll_array_size = context->n_poll_records; context->cached_poll_array = g_new (GPollFD, context->n_poll_records); } allocated_nfds = context->cached_poll_array_size; fds = context->cached_poll_array; g_main_context_prepare_unlocked (context, &max_priority); while ((nfds = g_main_context_query_unlocked ( context, max_priority, &timeout_usec, fds, allocated_nfds)) > allocated_nfds) { g_free (fds); context->cached_poll_array_size = allocated_nfds = nfds; context->cached_poll_array = fds = g_new (GPollFD, nfds); } if (!block) timeout_usec = 0; g_main_context_poll_unlocked (context, timeout_usec, max_priority, fds, nfds); some_ready = g_main_context_check_unlocked (context, max_priority, fds, nfds); if (dispatch) g_main_context_dispatch_unlocked (context); g_main_context_release_unlocked (context); g_trace_mark (begin_time_nsec, G_TRACE_CURRENT_TIME - begin_time_nsec, "GLib", "g_main_context_iterate", "Context %p, %s ⇒ %s", context, block ? "blocking" : "non-blocking", some_ready ? "dispatched" : "nothing"); return some_ready; } /** * g_main_context_pending: * @context: (nullable): a main context (if `NULL`, the global-default * main context will be used) * * Checks if any sources have pending events for the given context. * * Returns: true if events are pending, false otherwise **/ gboolean g_main_context_pending (GMainContext *context) { gboolean retval; if (!context) context = g_main_context_default(); LOCK_CONTEXT (context); retval = g_main_context_iterate_unlocked (context, FALSE, FALSE, G_THREAD_SELF); UNLOCK_CONTEXT (context); return retval; } /** * g_main_context_iteration: * @context: (nullable): a main context (if `NULL`, the global-default * main context will be used) * @may_block: whether the call may block * * Runs a single iteration for the given main loop. * * This involves * checking to see if any event sources are ready to be processed, * then if no events sources are ready and @may_block is true, waiting * for a source to become ready, then dispatching the highest priority * events sources that are ready. Otherwise, if @may_block is false, * this function does not wait for sources to become ready, and only the highest * priority sources which are already ready (if any) will be dispatched. * * Note that even when @may_block is true, it is still possible for * [method@GLib.MainContext.iteration] to return false, since the wait may * be interrupted for other reasons than an event source becoming ready. * * Returns: true if events were dispatched, false otherwise **/ gboolean g_main_context_iteration (GMainContext *context, gboolean may_block) { gboolean retval; if (!context) context = g_main_context_default(); LOCK_CONTEXT (context); retval = g_main_context_iterate_unlocked (context, may_block, TRUE, G_THREAD_SELF); UNLOCK_CONTEXT (context); return retval; } /** * g_main_loop_new: * @context: (nullable): a main context (if `NULL`, the global-default * main context will be used). * @is_running: set to true to indicate that the loop is running. This * is not very important since calling [method@GLib.MainLoop.run] will set this * to true anyway. * * Creates a new [struct@GLib.MainLoop] structure. * * Returns: (transfer full): a new main loop **/ GMainLoop * g_main_loop_new (GMainContext *context, gboolean is_running) { GMainLoop *loop; if (!context) context = g_main_context_default(); g_main_context_ref (context); loop = g_new0 (GMainLoop, 1); loop->context = context; loop->is_running = is_running != FALSE; loop->ref_count = 1; TRACE (GLIB_MAIN_LOOP_NEW (loop, context)); return loop; } /** * g_main_loop_ref: * @loop: a main loop * * Increases the reference count on a [struct@GLib.MainLoop] object by one. * * Returns: @loop **/ GMainLoop * g_main_loop_ref (GMainLoop *loop) { g_return_val_if_fail (loop != NULL, NULL); g_return_val_if_fail (g_atomic_int_get (&loop->ref_count) > 0, NULL); g_atomic_int_inc (&loop->ref_count); return loop; } /** * g_main_loop_unref: * @loop: a main loop * * Decreases the reference count on a [struct@GLib.MainLoop] object by one. * * If the result is zero, the loop and all associated memory are freed. **/ void g_main_loop_unref (GMainLoop *loop) { g_return_if_fail (loop != NULL); g_return_if_fail (g_atomic_int_get (&loop->ref_count) > 0); if (!g_atomic_int_dec_and_test (&loop->ref_count)) return; g_main_context_unref (loop->context); g_free (loop); } /** * g_main_loop_run: * @loop: a main loop * * Runs a main loop until [method@GLib.MainLoop.quit] is called on the loop. * * If this is called from the thread of the loop’s [struct@GLib.MainContext], * it will process events from the loop, otherwise it will * simply wait. **/ void g_main_loop_run (GMainLoop *loop) { GThread *self = G_THREAD_SELF; g_return_if_fail (loop != NULL); g_return_if_fail (g_atomic_int_get (&loop->ref_count) > 0); /* Hold a reference in case the loop is unreffed from a callback function */ g_atomic_int_inc (&loop->ref_count); LOCK_CONTEXT (loop->context); if (!g_main_context_acquire_unlocked (loop->context)) { gboolean got_ownership = FALSE; /* Another thread owns this context */ g_atomic_int_set (&loop->is_running, TRUE); while (g_atomic_int_get (&loop->is_running) && !got_ownership) got_ownership = g_main_context_wait_internal (loop->context, &loop->context->cond, &loop->context->mutex); if (!g_atomic_int_get (&loop->is_running)) { if (got_ownership) g_main_context_release_unlocked (loop->context); UNLOCK_CONTEXT (loop->context); g_main_loop_unref (loop); return; } g_assert (got_ownership); } if G_UNLIKELY (loop->context->in_check_or_prepare) { g_warning ("g_main_loop_run(): called recursively from within a source's " "check() or prepare() member, iteration not possible."); g_main_context_release_unlocked (loop->context); UNLOCK_CONTEXT (loop->context); g_main_loop_unref (loop); return; } g_atomic_int_set (&loop->is_running, TRUE); while (g_atomic_int_get (&loop->is_running)) g_main_context_iterate_unlocked (loop->context, TRUE, TRUE, self); g_main_context_release_unlocked (loop->context); UNLOCK_CONTEXT (loop->context); g_main_loop_unref (loop); } /** * g_main_loop_quit: * @loop: a main loop * * Stops a [struct@GLib.MainLoop] from running. Any calls to * [method@GLib.MainLoop.run] for the loop will return. * * Note that sources that have already been dispatched when * [method@GLib.MainLoop.quit] is called will still be executed. **/ void g_main_loop_quit (GMainLoop *loop) { g_return_if_fail (loop != NULL); g_return_if_fail (g_atomic_int_get (&loop->ref_count) > 0); LOCK_CONTEXT (loop->context); g_atomic_int_set (&loop->is_running, FALSE); g_wakeup_signal (loop->context->wakeup); g_cond_broadcast (&loop->context->cond); UNLOCK_CONTEXT (loop->context); TRACE (GLIB_MAIN_LOOP_QUIT (loop)); } /** * g_main_loop_is_running: * @loop: a main loop * * Checks to see if the main loop is currently being run via * [method@GLib.MainLoop.run]. * * Returns: true if the main loop is currently being run, false otherwise **/ gboolean g_main_loop_is_running (GMainLoop *loop) { g_return_val_if_fail (loop != NULL, FALSE); g_return_val_if_fail (g_atomic_int_get (&loop->ref_count) > 0, FALSE); return g_atomic_int_get (&loop->is_running); } /** * g_main_loop_get_context: * @loop: a main loop * * Returns the [struct@GLib.MainContext] of @loop. * * Returns: (transfer none): the [struct@GLib.MainContext] of @loop **/ GMainContext * g_main_loop_get_context (GMainLoop *loop) { g_return_val_if_fail (loop != NULL, NULL); g_return_val_if_fail (g_atomic_int_get (&loop->ref_count) > 0, NULL); return loop->context; } /* HOLDS: context's lock */ static void g_main_context_poll_unlocked (GMainContext *context, gint64 timeout_usec, int priority, GPollFD *fds, int n_fds) { #ifdef G_MAIN_POLL_DEBUG GTimer *poll_timer; GPollRec *pollrec; gint i; #endif GPollFunc poll_func; if (n_fds || timeout_usec != 0) { int ret, errsv; #ifdef G_MAIN_POLL_DEBUG poll_timer = NULL; if (_g_main_poll_debug) { g_print ("polling context=%p n=%d timeout_usec=%"G_GINT64_FORMAT"\n", context, n_fds, timeout_usec); poll_timer = g_timer_new (); } #endif poll_func = context->poll_func; #if defined(HAVE_PPOLL) && defined(HAVE_POLL) if (poll_func == g_poll) { struct timespec spec; struct timespec *spec_p = NULL; if (timeout_usec > -1) { spec.tv_sec = timeout_usec / G_USEC_PER_SEC; spec.tv_nsec = (timeout_usec % G_USEC_PER_SEC) * 1000L; spec_p = &spec; } UNLOCK_CONTEXT (context); ret = ppoll ((struct pollfd *) fds, n_fds, spec_p, NULL); LOCK_CONTEXT (context); } else #endif { int timeout_msec = round_timeout_to_msec (timeout_usec); UNLOCK_CONTEXT (context); ret = (*poll_func) (fds, n_fds, timeout_msec); LOCK_CONTEXT (context); } errsv = errno; if (ret < 0 && errsv != EINTR) { #ifndef G_OS_WIN32 g_warning ("poll(2) failed due to: %s.", g_strerror (errsv)); #else /* If g_poll () returns -1, it has already called g_warning() */ #endif } #ifdef G_MAIN_POLL_DEBUG if (_g_main_poll_debug) { g_print ("g_main_poll(%d) timeout_usec: %"G_GINT64_FORMAT" - elapsed %12.10f seconds", n_fds, timeout_usec, g_timer_elapsed (poll_timer, NULL)); g_timer_destroy (poll_timer); pollrec = context->poll_records; while (pollrec != NULL) { i = 0; while (i < n_fds) { if (fds[i].fd == pollrec->fd->fd && pollrec->fd->events && fds[i].revents) { g_print (" [" G_POLLFD_FORMAT " :", fds[i].fd); if (fds[i].revents & G_IO_IN) g_print ("i"); if (fds[i].revents & G_IO_OUT) g_print ("o"); if (fds[i].revents & G_IO_PRI) g_print ("p"); if (fds[i].revents & G_IO_ERR) g_print ("e"); if (fds[i].revents & G_IO_HUP) g_print ("h"); if (fds[i].revents & G_IO_NVAL) g_print ("n"); g_print ("]"); } i++; } pollrec = pollrec->next; } g_print ("\n"); } #endif } /* if (n_fds || timeout_usec != 0) */ } /** * g_main_context_add_poll: * @context: (nullable): a main context (or `NULL` for the global-default * main context) * @fd: a [struct@GLib.PollFD] structure holding information about a file * descriptor to watch. * @priority: the priority for this file descriptor which should be * the same as the priority used for [method@GLib.Source.attach] to ensure * that the file descriptor is polled whenever the results may be needed. * * Adds a file descriptor to the set of file descriptors polled for * this context. * * This will very seldom be used directly. Instead * a typical event source will use `g_source_add_unix_fd()` instead. **/ void g_main_context_add_poll (GMainContext *context, GPollFD *fd, gint priority) { if (!context) context = g_main_context_default (); g_return_if_fail (g_atomic_int_get (&context->ref_count) > 0); g_return_if_fail (fd); LOCK_CONTEXT (context); g_main_context_add_poll_unlocked (context, priority, fd); UNLOCK_CONTEXT (context); } /* HOLDS: main_loop_lock */ static void g_main_context_add_poll_unlocked (GMainContext *context, gint priority, GPollFD *fd) { GPollRec *prevrec, *nextrec; GPollRec *newrec = g_slice_new (GPollRec); /* This file descriptor may be checked before we ever poll */ fd->revents = 0; newrec->fd = fd; newrec->priority = priority; /* Poll records are incrementally sorted by file descriptor identifier. */ prevrec = NULL; nextrec = context->poll_records; while (nextrec) { if (nextrec->fd->fd > fd->fd) break; prevrec = nextrec; nextrec = nextrec->next; } if (prevrec) prevrec->next = newrec; else context->poll_records = newrec; newrec->prev = prevrec; newrec->next = nextrec; if (nextrec) nextrec->prev = newrec; context->n_poll_records++; context->poll_changed = TRUE; /* Now wake up the main loop if it is waiting in the poll() */ if (fd != &context->wake_up_rec) g_wakeup_signal (context->wakeup); } /** * g_main_context_remove_poll: * @context: (nullable): a main context (if `NULL`, the global-default * main context will be used) * @fd: a [struct@GLib.PollFD] descriptor previously added with * [method@GLib.MainContext.add_poll] * * Removes file descriptor from the set of file descriptors to be * polled for a particular context. **/ void g_main_context_remove_poll (GMainContext *context, GPollFD *fd) { if (!context) context = g_main_context_default (); g_return_if_fail (g_atomic_int_get (&context->ref_count) > 0); g_return_if_fail (fd); LOCK_CONTEXT (context); g_main_context_remove_poll_unlocked (context, fd); UNLOCK_CONTEXT (context); } static void g_main_context_remove_poll_unlocked (GMainContext *context, GPollFD *fd) { GPollRec *pollrec, *prevrec, *nextrec; prevrec = NULL; pollrec = context->poll_records; while (pollrec) { nextrec = pollrec->next; if (pollrec->fd == fd) { if (prevrec != NULL) prevrec->next = nextrec; else context->poll_records = nextrec; if (nextrec != NULL) nextrec->prev = prevrec; g_slice_free (GPollRec, pollrec); context->n_poll_records--; break; } prevrec = pollrec; pollrec = nextrec; } context->poll_changed = TRUE; /* Now wake up the main loop if it is waiting in the poll() */ g_wakeup_signal (context->wakeup); } /** * g_source_get_current_time: * @source: a source * @timeval: [struct@GLib.TimeVal] structure in which to store current time * * This function ignores @source and is otherwise the same as * [func@GLib.get_current_time]. * * Deprecated: 2.28: use [method@GLib.Source.get_time] instead **/ G_GNUC_BEGIN_IGNORE_DEPRECATIONS void g_source_get_current_time (GSource *source, GTimeVal *timeval) { g_get_current_time (timeval); } G_GNUC_END_IGNORE_DEPRECATIONS /** * g_source_get_time: * @source: a source * * Gets the time to be used when checking this source. * * The advantage of * calling this function over calling [func@GLib.get_monotonic_time] directly is * that when checking multiple sources, GLib can cache a single value * instead of having to repeatedly get the system monotonic time. * * The time here is the system monotonic time, if available, or some * other reasonable alternative otherwise. See [func@GLib.get_monotonic_time]. * * Returns: the monotonic time in microseconds * Since: 2.28 **/ gint64 g_source_get_time (GSource *source) { GMainContext *context; gint64 result; g_return_val_if_fail (source != NULL, 0); g_return_val_if_fail (g_atomic_int_get (&source->ref_count) > 0, 0); context = source_dup_main_context (source); g_return_val_if_fail (context != NULL, 0); LOCK_CONTEXT (context); if (!context->time_is_fresh) { context->time = g_get_monotonic_time (); context->time_is_fresh = TRUE; } result = context->time; UNLOCK_CONTEXT (context); g_main_context_unref (context); return result; } /** * g_main_context_set_poll_func: * @context: (nullable): a main context (if `NULL`, the global-default * main context will be used) * @func: the function to call to poll all file descriptors * * Sets the function to use to handle polling of file descriptors. * * It will be used instead of the [`poll()`](man:poll(2)) system call * (or GLib’s replacement function, which is used where * `poll()` isn’t available). * * This function could possibly be used to integrate the GLib event * loop with an external event loop. **/ void g_main_context_set_poll_func (GMainContext *context, GPollFunc func) { if (!context) context = g_main_context_default (); g_return_if_fail (g_atomic_int_get (&context->ref_count) > 0); LOCK_CONTEXT (context); if (func) context->poll_func = func; else context->poll_func = g_poll; UNLOCK_CONTEXT (context); } /** * g_main_context_get_poll_func: * @context: (nullable): a main context (if `NULL`, the global-default * main context will be used) * * Gets the poll function set by [method@GLib.MainContext.set_poll_func]. * * Returns: the poll function **/ GPollFunc g_main_context_get_poll_func (GMainContext *context) { GPollFunc result; if (!context) context = g_main_context_default (); g_return_val_if_fail (g_atomic_int_get (&context->ref_count) > 0, NULL); LOCK_CONTEXT (context); result = context->poll_func; UNLOCK_CONTEXT (context); return result; } /** * g_main_context_wakeup: * @context: (nullable): a main context (if `NULL`, the global-default * main context will be used) * * Wake up @context if it’s currently blocking in * [method@GLib.MainContext.iteration], causing it to stop blocking. * * The @context could be blocking waiting for a source to become ready. * Otherwise, if @context is not currently blocking, this function causes the * next invocation of [method@GLib.MainContext.iteration] to return without * blocking. * * This API is useful for low-level control over [struct@GLib.MainContext]; for * example, integrating it with main loop implementations such as * [struct@GLib.MainLoop]. * * Another related use for this function is when implementing a main * loop with a termination condition, computed from multiple threads: * * ```c * #define NUM_TASKS 10 * static gint tasks_remaining = NUM_TASKS; // (atomic) * ... * * while (g_atomic_int_get (&tasks_remaining) != 0) * g_main_context_iteration (NULL, TRUE); * ``` * * Then in a thread: * ```c * perform_work (); * * if (g_atomic_int_dec_and_test (&tasks_remaining)) * g_main_context_wakeup (NULL); * ``` **/ void g_main_context_wakeup (GMainContext *context) { if (!context) context = g_main_context_default (); g_return_if_fail (g_atomic_int_get (&context->ref_count) > 0); TRACE (GLIB_MAIN_CONTEXT_WAKEUP (context)); g_wakeup_signal (context->wakeup); } /** * g_main_context_is_owner: * @context: (nullable): a main context (if `NULL`, the global-default * main context will be used) * * Determines whether this thread holds the (recursive) * ownership of this [struct@GLib.MainContext]. * * This is useful to * know before waiting on another thread that may be * blocking to get ownership of @context. * * Returns: true if current thread is owner of @context, false otherwise * Since: 2.10 **/ gboolean g_main_context_is_owner (GMainContext *context) { gboolean is_owner; if (!context) context = g_main_context_default (); LOCK_CONTEXT (context); is_owner = context->owner == G_THREAD_SELF; UNLOCK_CONTEXT (context); return is_owner; } /* Timeouts */ static void g_timeout_set_expiration (GTimeoutSource *timeout_source, gint64 current_time) { gint64 expiration; if (timeout_source->seconds) { gint64 remainder; static gint timer_perturb = -1; if (timer_perturb == -1) { /* * we want a per machine/session unique 'random' value; try the dbus * address first, that has a UUID in it. If there is no dbus, use the * hostname for hashing. */ const char *session_bus_address = g_getenv ("DBUS_SESSION_BUS_ADDRESS"); if (!session_bus_address) session_bus_address = g_getenv ("HOSTNAME"); if (session_bus_address) timer_perturb = ABS ((gint) g_str_hash (session_bus_address)) % 1000000; else timer_perturb = 0; } expiration = current_time + (guint64) timeout_source->interval * 1000 * 1000; /* We want the microseconds part of the timeout to land on the * 'timer_perturb' mark, but we need to make sure we don't try to * set the timeout in the past. We do this by ensuring that we * always only *increase* the expiration time by adding a full * second in the case that the microsecond portion decreases. */ expiration -= timer_perturb; remainder = expiration % 1000000; if (remainder >= 1000000/4) expiration += 1000000; expiration -= remainder; expiration += timer_perturb; } else { expiration = current_time + (guint64) timeout_source->interval * 1000; } g_source_set_ready_time ((GSource *) timeout_source, expiration); } static gboolean g_timeout_dispatch (GSource *source, GSourceFunc callback, gpointer user_data) { GTimeoutSource *timeout_source = (GTimeoutSource *)source; gboolean again; if (!callback) { g_warning ("Timeout source dispatched without callback. " "You must call g_source_set_callback()."); return FALSE; } if (timeout_source->one_shot) { GSourceOnceFunc once_callback = (GSourceOnceFunc) callback; once_callback (user_data); again = G_SOURCE_REMOVE; } else { again = callback (user_data); } TRACE (GLIB_TIMEOUT_DISPATCH (source, source->context, callback, user_data, again)); if (again) g_timeout_set_expiration (timeout_source, g_source_get_time (source)); return again; } static GSource * timeout_source_new (guint interval, gboolean seconds, gboolean one_shot) { GSource *source = g_source_new (&g_timeout_funcs, sizeof (GTimeoutSource)); GTimeoutSource *timeout_source = (GTimeoutSource *)source; timeout_source->interval = interval; timeout_source->seconds = seconds; timeout_source->one_shot = one_shot; g_timeout_set_expiration (timeout_source, g_get_monotonic_time ()); return source; } /** * g_timeout_source_new: * @interval: the timeout interval in milliseconds * * Creates a new timeout source. * * The source will not initially be associated with any [struct@GLib.MainContext] * and must be added to one with [method@GLib.Source.attach] before it will be * executed. * * The interval given is in terms of monotonic time, not wall clock * time. See [func@GLib.get_monotonic_time]. * * Returns: (transfer full): the newly-created timeout source **/ GSource * g_timeout_source_new (guint interval) { return timeout_source_new (interval, FALSE, FALSE); } /** * g_timeout_source_new_seconds: * @interval: the timeout interval in seconds * * Creates a new timeout source. * * The source will not initially be associated with any * [struct@GLib.MainContext] and must be added to one with * [method@GLib.Source.attach] before it will be executed. * * The scheduling granularity/accuracy of this timeout source will be * in seconds. * * The interval given is in terms of monotonic time, not wall clock time. * See [func@GLib.get_monotonic_time]. * * Returns: (transfer full): the newly-created timeout source * Since: 2.14 **/ GSource * g_timeout_source_new_seconds (guint interval) { return timeout_source_new (interval, TRUE, FALSE); } static guint timeout_add_full (gint priority, guint interval, gboolean seconds, gboolean one_shot, GSourceFunc function, gpointer data, GDestroyNotify notify) { GSource *source; guint id; g_return_val_if_fail (function != NULL, 0); source = timeout_source_new (interval, seconds, one_shot); if (priority != G_PRIORITY_DEFAULT) g_source_set_priority (source, priority); g_source_set_callback (source, function, data, notify); id = g_source_attach (source, NULL); TRACE (GLIB_TIMEOUT_ADD (source, g_main_context_default (), id, priority, interval, function, data)); g_source_unref (source); return id; } /** * g_timeout_add_full: (rename-to g_timeout_add) * @priority: the priority of the timeout source; typically this will be in * the range between [const@GLib.PRIORITY_DEFAULT] and * [const@GLib.PRIORITY_HIGH] * @interval: the time between calls to the function, in milliseconds * @function: function to call * @data: data to pass to @function * @notify: (nullable): function to call when the timeout is removed * * Sets a function to be called at regular intervals, with the given * priority. * * The function is called repeatedly until it returns * [const@GLib.SOURCE_REMOVE], at which point the timeout is automatically * destroyed and * the function will not be called again. The @notify function is * called when the timeout is destroyed. The first call to the * function will be at the end of the first @interval. * * Note that timeout functions may be delayed, due to the processing of other * event sources. Thus they should not be relied on for precise timing. * After each call to the timeout function, the time of the next * timeout is recalculated based on the current time and the given interval * (it does not try to ‘catch up’ time lost in delays). * * See [main loop memory management](main-loop.html#memory-management-of-sources) for details * on how to handle the return value and memory management of @data. * * This internally creates a main loop source using * [func@GLib.timeout_source_new] and attaches it to the global * [struct@GLib.MainContext] using [method@GLib.Source.attach], so the callback * will be invoked in whichever thread is running that main context. You can do * these steps manually if you need greater control or to use a custom main * context. * * The interval given is in terms of monotonic time, not wall clock time. * See [func@GLib.get_monotonic_time]. * * Returns: the ID (greater than 0) of the event source **/ guint g_timeout_add_full (gint priority, guint interval, GSourceFunc function, gpointer data, GDestroyNotify notify) { return timeout_add_full (priority, interval, FALSE, FALSE, function, data, notify); } /** * g_timeout_add: * @interval: the time between calls to the function, in milliseconds * @function: function to call * @data: data to pass to @function * * Sets a function to be called at regular intervals, with the default * priority, [const@GLib.PRIORITY_DEFAULT]. * * The given @function is called repeatedly until it returns * [const@GLib.SOURCE_REMOVE], at which point the timeout is * automatically destroyed and the function will not be called again. The first * call to the function will be at the end of the first @interval. * * Note that timeout functions may be delayed, due to the processing of other * event sources. Thus they should not be relied on for precise timing. * After each call to the timeout function, the time of the next * timeout is recalculated based on the current time and the given interval * (it does not try to ‘catch up’ time lost in delays). * * See [main loop memory management](main-loop.html#memory-management-of-sources) for details * on how to handle the return value and memory management of @data. * * If you want to have a timer in the ‘seconds’ range and do not care * about the exact time of the first call of the timer, use the * [func@GLib.timeout_add_seconds] function; this function allows for more * optimizations and more efficient system power usage. * * This internally creates a main loop source using * [func@GLib.timeout_source_new] and attaches it to the global * [struct@GLib.MainContext] using [method@GLib.Source.attach], so the callback * will be invoked in whichever thread is running that main context. You can do * these steps manually if you need greater control or to use a custom main * context. * * It is safe to call this function from any thread. * * The interval given is in terms of monotonic time, not wall clock * time. See [func@GLib.get_monotonic_time]. * * Returns: the ID (greater than 0) of the event source **/ guint g_timeout_add (guint32 interval, GSourceFunc function, gpointer data) { return g_timeout_add_full (G_PRIORITY_DEFAULT, interval, function, data, NULL); } /** * g_timeout_add_once: * @interval: the time after which the function will be called, in milliseconds * @function: function to call * @data: data to pass to @function * * Sets a function to be called after @interval milliseconds have elapsed, * with the default priority, [const@GLib.PRIORITY_DEFAULT]. * * The given @function is called once and then the source will be automatically * removed from the main context. * * This function otherwise behaves like [func@GLib.timeout_add]. * * Returns: the ID (greater than 0) of the event source * Since: 2.74 */ guint g_timeout_add_once (guint32 interval, GSourceOnceFunc function, gpointer data) { return timeout_add_full (G_PRIORITY_DEFAULT, interval, FALSE, TRUE, (GSourceFunc) function, data, NULL); } /** * g_timeout_add_seconds_full: (rename-to g_timeout_add_seconds) * @priority: the priority of the timeout source; typically this will be in * the range between [const@GLib.PRIORITY_DEFAULT] and * [const@GLib.PRIORITY_HIGH] * @interval: the time between calls to the function, in seconds * @function: function to call * @data: data to pass to @function * @notify: (nullable): function to call when the timeout is removed * * Sets a function to be called at regular intervals, with @priority. * * The function is called repeatedly until it returns [const@GLib.SOURCE_REMOVE], * at which point the timeout is automatically destroyed and * the function will not be called again. * * Unlike [func@GLib.timeout_add], this function operates at whole second * granularity. The initial starting point of the timer is determined by the * implementation and the implementation is expected to group multiple timers * together so that they fire all at the same time. To allow this grouping, * the @interval to the first timer is rounded and can deviate up to one second * from the specified interval. Subsequent timer iterations will generally run * at the specified interval. * * Note that timeout functions may be delayed, due to the processing of other * event sources. Thus they should not be relied on for precise timing. * After each call to the timeout function, the time of the next * timeout is recalculated based on the current time and the given @interval * * See [main loop memory management](main-loop.html#memory-management-of-sources) for details * on how to handle the return value and memory management of @data. * * If you want timing more precise than whole seconds, use * [func@GLib.timeout_add] instead. * * The grouping of timers to fire at the same time results in a more power * and CPU efficient behavior so if your timer is in multiples of seconds * and you don’t require the first timer exactly one second from now, the * use of [func@GLib.timeout_add_seconds] is preferred over * [func@GLib.timeout_add]. * * This internally creates a main loop source using * [func@GLib.timeout_source_new_seconds] and attaches it to the main loop * context using [method@GLib.Source.attach]. You can do these steps manually * if you need greater control. * * It is safe to call this function from any thread. * * The interval given is in terms of monotonic time, not wall clock * time. See [func@GLib.get_monotonic_time]. * * Returns: the ID (greater than 0) of the event source * Since: 2.14 **/ guint g_timeout_add_seconds_full (gint priority, guint32 interval, GSourceFunc function, gpointer data, GDestroyNotify notify) { return timeout_add_full (priority, interval, TRUE, FALSE, function, data, notify); } /** * g_timeout_add_seconds: * @interval: the time between calls to the function, in seconds * @function: function to call * @data: data to pass to @function * * Sets a function to be called at regular intervals with the default * priority, [const@GLib.PRIORITY_DEFAULT]. * * The function is called repeatedly until it returns [const@GLib.SOURCE_REMOVE], * at which point the timeout is automatically destroyed * and the function will not be called again. * * This internally creates a main loop source using * [func@GLib.timeout_source_new_seconds] and attaches it to the main loop context * using [method@GLib.Source.attach]. You can do these steps manually if you need * greater control. Also see [func@GLib.timeout_add_seconds_full]. * * It is safe to call this function from any thread. * * Note that the first call of the timer may not be precise for timeouts * of one second. If you need finer precision and have such a timeout, * you may want to use [func@GLib.timeout_add] instead. * * See [main loop memory management](main-loop.html#memory-management-of-sources) for details * on how to handle the return value and memory management of @data. * * The interval given is in terms of monotonic time, not wall clock * time. See [func@GLib.get_monotonic_time]. * * Returns: the ID (greater than 0) of the event source * Since: 2.14 **/ guint g_timeout_add_seconds (guint interval, GSourceFunc function, gpointer data) { g_return_val_if_fail (function != NULL, 0); return g_timeout_add_seconds_full (G_PRIORITY_DEFAULT, interval, function, data, NULL); } /** * g_timeout_add_seconds_once: * @interval: the time after which the function will be called, in seconds * @function: function to call * @data: data to pass to @function * * This function behaves like [func@GLib.timeout_add_once] but with a range in * seconds. * * Returns: the ID (greater than 0) of the event source * Since: 2.78 */ guint g_timeout_add_seconds_once (guint interval, GSourceOnceFunc function, gpointer data) { return timeout_add_full (G_PRIORITY_DEFAULT, interval, TRUE, TRUE, (GSourceFunc) function, data, NULL); } /* Child watch functions */ #ifdef HAVE_PIDFD static int siginfo_t_to_wait_status (const siginfo_t *info) { /* Each of these returns is essentially the inverse of WIFEXITED(), * WIFSIGNALED(), etc. */ switch (info->si_code) { case CLD_EXITED: return W_EXITCODE (info->si_status, 0); case CLD_KILLED: return W_EXITCODE (0, info->si_status); case CLD_DUMPED: return W_EXITCODE (0, info->si_status | WCOREFLAG); case CLD_CONTINUED: return __W_CONTINUED; case CLD_STOPPED: case CLD_TRAPPED: default: return W_STOPCODE (info->si_status); } } #endif /* HAVE_PIDFD */ static gboolean g_child_watch_prepare (GSource *source, gint *timeout) { #ifdef G_OS_WIN32 return FALSE; #else /* G_OS_WIN32 */ { GChildWatchSource *child_watch_source; child_watch_source = (GChildWatchSource *) source; if (child_watch_source->poll.fd >= 0) return FALSE; return g_atomic_int_get (&child_watch_source->child_maybe_exited); } #endif /* G_OS_WIN32 */ } static gboolean g_child_watch_check (GSource *source) { GChildWatchSource *child_watch_source; gboolean child_exited; child_watch_source = (GChildWatchSource *) source; #ifdef G_OS_WIN32 child_exited = !!(child_watch_source->poll.revents & G_IO_IN); #else /* G_OS_WIN32 */ #ifdef HAVE_PIDFD if (child_watch_source->poll.fd >= 0) { child_exited = !!(child_watch_source->poll.revents & G_IO_IN); return child_exited; } #endif /* HAVE_PIDFD */ child_exited = g_atomic_int_get (&child_watch_source->child_maybe_exited); #endif /* G_OS_WIN32 */ return child_exited; } static void g_child_watch_finalize (GSource *source) { #ifndef G_OS_WIN32 GChildWatchSource *child_watch_source = (GChildWatchSource *) source; if (child_watch_source->poll.fd >= 0) { close (child_watch_source->poll.fd); return; } G_LOCK (unix_signal_lock); unix_child_watches = g_slist_remove (unix_child_watches, source); unref_unix_signal_handler_unlocked (SIGCHLD); G_UNLOCK (unix_signal_lock); #endif /* G_OS_WIN32 */ } #ifndef G_OS_WIN32 static void wake_source (GSource *source) { GMainContext *context; /* This should be thread-safe: * * - if the source is currently being added to a context, that * context will be woken up anyway * * - if the source is currently being destroyed, we simply need not * to crash: * * - the memory for the source will remain valid until after the * source finalize function was called (which would remove the * source from the global list which we are currently holding the * lock for) * * - the GMainContext will either be NULL or point to a live * GMainContext * * - the GMainContext will remain valid since source_dup_main_context() * gave us a ref or NULL * * Since we are holding a lot of locks here, don't try to enter any * more GMainContext functions for fear of dealock -- just hit the * GWakeup and run. Even if that's safe now, it could easily become * unsafe with some very minor changes in the future, and signal * handling is not the most well-tested codepath. */ context = source_dup_main_context (source); if (context) g_wakeup_signal (context->wakeup); if (context) g_main_context_unref (context); } static void dispatch_unix_signals_unlocked (void) { gboolean pending[NSIG]; GSList *node; gint i; /* clear this first in case another one arrives while we're processing */ g_atomic_int_set (&any_unix_signal_pending, 0); /* We atomically test/clear the bit from the global array in case * other signals arrive while we are dispatching. * * We then can safely use our own array below without worrying about * races. */ for (i = 0; i < NSIG; i++) { /* Be very careful with (the volatile) unix_signal_pending. * * We must ensure that it's not possible that we clear it without * handling the signal. We therefore must ensure that our pending * array has a field set (ie: we will do something about the * signal) before we clear the item in unix_signal_pending. * * Note specifically: we must check _our_ array. */ pending[i] = g_atomic_int_compare_and_exchange (&unix_signal_pending[i], 1, 0); } /* handle GChildWatchSource instances */ if (pending[SIGCHLD]) { /* The only way we can do this is to scan all of the children. * * The docs promise that we will not reap children that we are not * explicitly watching, so that ties our hands from calling * waitpid(-1). We also can't use siginfo's si_pid field since if * multiple SIGCHLD arrive at the same time, one of them can be * dropped (since a given UNIX signal can only be pending once). */ for (node = unix_child_watches; node; node = node->next) { GChildWatchSource *source = node->data; if (g_atomic_int_compare_and_exchange (&source->child_maybe_exited, FALSE, TRUE)) wake_source ((GSource *) source); } } /* handle GUnixSignalWatchSource instances */ for (node = unix_signal_watches; node; node = node->next) { GUnixSignalWatchSource *source = node->data; if (pending[source->signum] && g_atomic_int_compare_and_exchange (&source->pending, FALSE, TRUE)) { wake_source ((GSource *) source); } } } static void dispatch_unix_signals (void) { G_LOCK(unix_signal_lock); dispatch_unix_signals_unlocked (); G_UNLOCK(unix_signal_lock); } static gboolean g_unix_signal_watch_prepare (GSource *source, gint *timeout) { GUnixSignalWatchSource *unix_signal_source; unix_signal_source = (GUnixSignalWatchSource *) source; return g_atomic_int_get (&unix_signal_source->pending); } static gboolean g_unix_signal_watch_check (GSource *source) { GUnixSignalWatchSource *unix_signal_source; unix_signal_source = (GUnixSignalWatchSource *) source; return g_atomic_int_get (&unix_signal_source->pending); } static gboolean g_unix_signal_watch_dispatch (GSource *source, GSourceFunc callback, gpointer user_data) { GUnixSignalWatchSource *unix_signal_source; gboolean again; unix_signal_source = (GUnixSignalWatchSource *) source; if (!callback) { g_warning ("Unix signal source dispatched without callback. " "You must call g_source_set_callback()."); return FALSE; } g_atomic_int_set (&unix_signal_source->pending, FALSE); again = (callback) (user_data); return again; } static void ref_unix_signal_handler_unlocked (int signum) { /* Ensure we have the worker context */ g_get_worker_context (); unix_signal_refcount[signum]++; if (unix_signal_refcount[signum] == 1) { struct sigaction action; action.sa_handler = g_unix_signal_handler; sigemptyset (&action.sa_mask); #ifdef SA_RESTART action.sa_flags = SA_RESTART | SA_NOCLDSTOP; #else action.sa_flags = SA_NOCLDSTOP; #endif #ifdef SA_ONSTACK action.sa_flags |= SA_ONSTACK; #endif sigaction (signum, &action, NULL); } } static void unref_unix_signal_handler_unlocked (int signum) { unix_signal_refcount[signum]--; if (unix_signal_refcount[signum] == 0) { struct sigaction action; memset (&action, 0, sizeof (action)); action.sa_handler = SIG_DFL; sigemptyset (&action.sa_mask); sigaction (signum, &action, NULL); } } /* Return a const string to avoid allocations. We lose precision in the case the * @signum is unrecognised, but that’ll do. */ static const gchar * signum_to_string (int signum) { /* See `man 0P signal.h` */ #define SIGNAL(s) \ case (s): \ return ("GUnixSignalSource: " #s); switch (signum) { /* These signals are guaranteed to exist by POSIX. */ SIGNAL (SIGABRT) SIGNAL (SIGFPE) SIGNAL (SIGILL) SIGNAL (SIGINT) SIGNAL (SIGSEGV) SIGNAL (SIGTERM) /* Frustratingly, these are not, and hence for brevity the list is * incomplete. */ #ifdef SIGALRM SIGNAL (SIGALRM) #endif #ifdef SIGCHLD SIGNAL (SIGCHLD) #endif #ifdef SIGHUP SIGNAL (SIGHUP) #endif #ifdef SIGKILL SIGNAL (SIGKILL) #endif #ifdef SIGPIPE SIGNAL (SIGPIPE) #endif #ifdef SIGQUIT SIGNAL (SIGQUIT) #endif #ifdef SIGSTOP SIGNAL (SIGSTOP) #endif #ifdef SIGUSR1 SIGNAL (SIGUSR1) #endif #ifdef SIGUSR2 SIGNAL (SIGUSR2) #endif #ifdef SIGPOLL SIGNAL (SIGPOLL) #endif #ifdef SIGPROF SIGNAL (SIGPROF) #endif #ifdef SIGTRAP SIGNAL (SIGTRAP) #endif default: return "GUnixSignalSource: Unrecognized signal"; } #undef SIGNAL } GSource * _g_main_create_unix_signal_watch (int signum) { GSource *source; GUnixSignalWatchSource *unix_signal_source; source = g_source_new (&g_unix_signal_funcs, sizeof (GUnixSignalWatchSource)); unix_signal_source = (GUnixSignalWatchSource *) source; unix_signal_source->signum = signum; unix_signal_source->pending = FALSE; /* Set a default name on the source, just in case the caller does not. */ g_source_set_static_name (source, signum_to_string (signum)); G_LOCK (unix_signal_lock); ref_unix_signal_handler_unlocked (signum); unix_signal_watches = g_slist_prepend (unix_signal_watches, unix_signal_source); dispatch_unix_signals_unlocked (); G_UNLOCK (unix_signal_lock); return source; } static void g_unix_signal_watch_finalize (GSource *source) { GUnixSignalWatchSource *unix_signal_source; unix_signal_source = (GUnixSignalWatchSource *) source; G_LOCK (unix_signal_lock); unref_unix_signal_handler_unlocked (unix_signal_source->signum); unix_signal_watches = g_slist_remove (unix_signal_watches, source); G_UNLOCK (unix_signal_lock); } #endif /* G_OS_WIN32 */ static gboolean g_child_watch_dispatch (GSource *source, GSourceFunc callback, gpointer user_data) { GChildWatchSource *child_watch_source; GChildWatchFunc child_watch_callback = (GChildWatchFunc) callback; int wait_status; child_watch_source = (GChildWatchSource *) source; /* We only (try to) reap the child process right before dispatching the callback. * That way, the caller can rely that the process is there until the callback * is invoked; or, if the caller calls g_source_destroy() without the callback * being dispatched, the process is still not reaped. */ #ifdef G_OS_WIN32 { DWORD child_status; /* * Note: We do _not_ check for the special value of STILL_ACTIVE * since we know that the process has exited and doing so runs into * problems if the child process "happens to return STILL_ACTIVE(259)" * as Microsoft's Platform SDK puts it. */ if (!GetExitCodeProcess (child_watch_source->pid, &child_status)) { gchar *emsg = g_win32_error_message (GetLastError ()); g_warning (G_STRLOC ": GetExitCodeProcess() failed: %s", emsg); g_free (emsg); /* Unknown error. We got signaled that the process might be exited, * but now we failed to reap it? Assume the process is gone and proceed. */ wait_status = -1; } else wait_status = child_status; } #else /* G_OS_WIN32 */ { gboolean child_exited = FALSE; wait_status = -1; #ifdef HAVE_PIDFD if (child_watch_source->poll.fd >= 0) { siginfo_t child_info = { 0, }; /* Get the exit status */ if (waitid (P_PIDFD, child_watch_source->poll.fd, &child_info, WEXITED | WNOHANG) >= 0) { if (child_info.si_pid != 0) { /* waitid() helpfully provides the wait status in a decomposed * form which is quite useful. Unfortunately we have to report it * to the #GChildWatchFunc as a waitpid()-style platform-specific * wait status, so that the user code in #GChildWatchFunc can then * call WIFEXITED() (etc.) on it. That means re-composing the * status information. */ wait_status = siginfo_t_to_wait_status (&child_info); child_exited = TRUE; } else { g_debug (G_STRLOC ": pidfd signaled but pid %" G_PID_FORMAT " didn't exit", child_watch_source->pid); return TRUE; } } else { int errsv = errno; g_warning (G_STRLOC ": waitid(pid:%" G_PID_FORMAT ", pidfd=%d) failed: %s (%d). %s", child_watch_source->pid, child_watch_source->poll.fd, g_strerror (errsv), errsv, "See documentation of g_child_watch_source_new() for possible causes."); /* Assume the process is gone and proceed. */ child_exited = TRUE; } } #endif /* HAVE_PIDFD*/ if (!child_exited) { pid_t pid; int wstatus; waitpid_again: /* We must reset the flag before waitpid(). Otherwise, there would be a * race. */ g_atomic_int_set (&child_watch_source->child_maybe_exited, FALSE); pid = waitpid (child_watch_source->pid, &wstatus, WNOHANG); if (G_UNLIKELY (pid < 0 && errno == EINTR)) goto waitpid_again; if (pid == 0) { /* Not exited yet. Wait longer. */ return TRUE; } if (pid > 0) wait_status = wstatus; else { int errsv = errno; g_warning (G_STRLOC ": waitpid(pid:%" G_PID_FORMAT ") failed: %s (%d). %s", child_watch_source->pid, g_strerror (errsv), errsv, "See documentation of g_child_watch_source_new() for possible causes."); /* Assume the process is gone and proceed. */ } } } #endif /* G_OS_WIN32 */ if (!callback) { g_warning ("Child watch source dispatched without callback. " "You must call g_source_set_callback()."); return FALSE; } (child_watch_callback) (child_watch_source->pid, wait_status, user_data); /* We never keep a child watch source around as the child is gone */ return FALSE; } #ifndef G_OS_WIN32 static void g_unix_signal_handler (int signum) { gint saved_errno = errno; #if defined(G_ATOMIC_LOCK_FREE) && defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4) g_atomic_int_set (&unix_signal_pending[signum], 1); g_atomic_int_set (&any_unix_signal_pending, 1); #else #warning "Can't use atomics in g_unix_signal_handler(): Unix signal handling will be racy" unix_signal_pending[signum] = 1; any_unix_signal_pending = 1; #endif g_wakeup_signal (glib_worker_context->wakeup); errno = saved_errno; } #endif /* !G_OS_WIN32 */ /** * g_child_watch_source_new: * @pid: process to watch — on POSIX systems, this is the positive PID of a * child process; on Windows it is a handle for a process (which doesn’t have * to be a child) * * Creates a new child watch source. * * The source will not initially be associated with any * [struct@GLib.MainContext] and must be added to one with * [method@GLib.Source.attach] before it will be executed. * * Note that child watch sources can only be used in conjunction with * `g_spawn...` when the [flags@GLib.SpawnFlags.DO_NOT_REAP_CHILD] flag is used. * * Note that on platforms where [type@GLib.Pid] must be explicitly closed * (see [func@GLib.spawn_close_pid]) @pid must not be closed while the * source is still active. Typically, you will want to call * [func@GLib.spawn_close_pid] in the callback function for the source. * * On POSIX platforms, the following restrictions apply to this API * due to limitations in POSIX process interfaces: * * * @pid must be a child of this process. * * @pid must be positive. * * The application must not call [`waitpid()`](man:waitpid(1)) with a * non-positive first argument, for instance in another thread. * * The application must not wait for @pid to exit by any other * mechanism, including `waitpid(pid, ...)` or a second child-watch * source for the same @pid. * * The application must not ignore `SIGCHLD`. * * Before 2.78, the application could not send a signal ([`kill()`](man:kill(2))) to the * watched @pid in a race free manner. Since 2.78, you can do that while the * associated [struct@GLib.MainContext] is acquired. * * Before 2.78, even after destroying the [struct@GLib.Source], you could not * be sure that @pid wasn’t already reaped. Hence, it was also not * safe to `kill()` or `waitpid()` on the process ID after the child watch * source was gone. Destroying the source before it fired made it * impossible to reliably reap the process. * * If any of those conditions are not met, this and related APIs will * not work correctly. This can often be diagnosed via a GLib warning * stating that `ECHILD` was received by `waitpid()`. * * Calling [`waitpid()`](man:waitpid(2)) for specific processes other than @pid * remains a valid thing to do. * * Returns: (transfer full): the newly-created child watch source * Since: 2.4 **/ GSource * g_child_watch_source_new (GPid pid) { GSource *source; GChildWatchSource *child_watch_source; #ifdef HAVE_PIDFD int errsv; #endif #ifndef G_OS_WIN32 g_return_val_if_fail (pid > 0, NULL); #endif source = g_source_new (&g_child_watch_funcs, sizeof (GChildWatchSource)); child_watch_source = (GChildWatchSource *)source; /* Set a default name on the source, just in case the caller does not. */ g_source_set_static_name (source, "GChildWatchSource"); child_watch_source->pid = pid; #ifdef G_OS_WIN32 child_watch_source->poll.fd = (gintptr) pid; child_watch_source->poll.events = G_IO_IN; g_source_add_poll (source, &child_watch_source->poll); #else /* !G_OS_WIN32 */ #ifdef HAVE_PIDFD /* Use a pidfd, if possible, to avoid having to install a global SIGCHLD * handler and potentially competing with any other library/code which wants * to install one. * * Unfortunately this use of pidfd isn’t race-free (the PID could be recycled * between the caller calling g_child_watch_source_new() and here), but it’s * better than SIGCHLD. */ child_watch_source->poll.fd = (int) syscall (SYS_pidfd_open, pid, 0); if (child_watch_source->poll.fd >= 0) { child_watch_source->poll.events = G_IO_IN; g_source_add_poll (source, &child_watch_source->poll); return source; } errsv = errno; g_debug ("pidfd_open(%" G_PID_FORMAT ") failed with error: %s", pid, g_strerror (errsv)); /* Fall through; likely the kernel isn’t new enough to support pidfd_open() */ #endif /* HAVE_PIDFD */ /* We can do that without atomic, as the source is not yet added in * unix_child_watches (which we do next under a lock). */ child_watch_source->child_maybe_exited = TRUE; child_watch_source->poll.fd = -1; G_LOCK (unix_signal_lock); ref_unix_signal_handler_unlocked (SIGCHLD); unix_child_watches = g_slist_prepend (unix_child_watches, child_watch_source); G_UNLOCK (unix_signal_lock); #endif /* !G_OS_WIN32 */ return source; } /** * g_child_watch_add_full: (rename-to g_child_watch_add) * @priority: the priority of the idle source; typically this will be in the * range between [const@GLib.PRIORITY_DEFAULT_IDLE] and * [const@GLib.PRIORITY_HIGH_IDLE] * @pid: process to watch — on POSIX systems, this is the positive PID of a * child process; on Windows it is a handle for a process (which doesn’t have * to be a child) * @function: function to call * @data: data to pass to @function * @notify: (nullable): function to call when the idle is removed * * Sets a function to be called when the child indicated by @pid * exits, at the priority @priority. * * If you obtain @pid from [func@GLib.spawn_async] or * [func@GLib.spawn_async_with_pipes] you will need to pass * [flags@GLib.SpawnFlags.DO_NOT_REAP_CHILD] as a flag to the spawn function for * the child watching to work. * * In many programs, you will want to call [func@GLib.spawn_check_wait_status] * in the callback to determine whether or not the child exited * successfully. * * Also, note that on platforms where [type@GLib.Pid] must be explicitly closed * (see [func@GLib.spawn_close_pid]) @pid must not be closed while the source * is still active. Typically, you should invoke [func@GLib.spawn_close_pid] * in the callback function for the source. * * GLib supports only a single callback per process ID. * On POSIX platforms, the same restrictions mentioned for * [func@GLib.child_watch_source_new] apply to this function. * * This internally creates a main loop source using * [func@GLib.child_watch_source_new] and attaches it to the main loop context * using [method@GLib.Source.attach]. You can do these steps manually if you * need greater control. * * Returns: the ID (greater than 0) of the event source * Since: 2.4 **/ guint g_child_watch_add_full (gint priority, GPid pid, GChildWatchFunc function, gpointer data, GDestroyNotify notify) { GSource *source; guint id; g_return_val_if_fail (function != NULL, 0); #ifndef G_OS_WIN32 g_return_val_if_fail (pid > 0, 0); #endif source = g_child_watch_source_new (pid); if (priority != G_PRIORITY_DEFAULT) g_source_set_priority (source, priority); g_source_set_callback (source, (GSourceFunc) function, data, notify); id = g_source_attach (source, NULL); g_source_unref (source); return id; } /** * g_child_watch_add: * @pid: process to watch — on POSIX systems, this is the positive PID of a * child process; on Windows it is a handle for a process (which doesn’t have * to be a child) * @function: function to call * @data: data to pass to @function * * Sets a function to be called when the child indicated by @pid * exits, at a default priority, [const@GLib.PRIORITY_DEFAULT]. * * If you obtain @pid from [func@GLib.spawn_async] or * [func@GLib.spawn_async_with_pipes] you will need to pass * [flags@GLib.SpawnFlags.DO_NOT_REAP_CHILD] as a flag to the spawn function for * the child watching to work. * * Note that on platforms where [type@GLib.Pid] must be explicitly closed * (see [func@GLib.spawn_close_pid]) @pid must not be closed while the * source is still active. Typically, you will want to call * [func@GLib.spawn_close_pid] in the callback function for the source. * * GLib supports only a single callback per process ID. * On POSIX platforms, the same restrictions mentioned for * [func@GLib.child_watch_source_new] apply to this function. * * This internally creates a main loop source using * [func@GLib.child_watch_source_new] and attaches it to the main loop context * using [method@GLib.Source.attach]. You can do these steps manually if you * need greater control. * * Returns: the ID (greater than 0) of the event source * Since: 2.4 **/ guint g_child_watch_add (GPid pid, GChildWatchFunc function, gpointer data) { return g_child_watch_add_full (G_PRIORITY_DEFAULT, pid, function, data, NULL); } /* Idle functions */ static gboolean g_idle_prepare (GSource *source, gint *timeout) { *timeout = 0; return TRUE; } static gboolean g_idle_check (GSource *source) { return TRUE; } static gboolean g_idle_dispatch (GSource *source, GSourceFunc callback, gpointer user_data) { GIdleSource *idle_source = (GIdleSource *)source; gboolean again; if (!callback) { g_warning ("Idle source dispatched without callback. " "You must call g_source_set_callback()."); return FALSE; } if (idle_source->one_shot) { GSourceOnceFunc once_callback = (GSourceOnceFunc) callback; once_callback (user_data); again = G_SOURCE_REMOVE; } else { again = callback (user_data); } TRACE (GLIB_IDLE_DISPATCH (source, source->context, callback, user_data, again)); return again; } static GSource * idle_source_new (gboolean one_shot) { GSource *source; GIdleSource *idle_source; source = g_source_new (&g_idle_funcs, sizeof (GIdleSource)); idle_source = (GIdleSource *) source; idle_source->one_shot = one_shot; g_source_set_priority (source, G_PRIORITY_DEFAULT_IDLE); /* Set a default name on the source, just in case the caller does not. */ g_source_set_static_name (source, "GIdleSource"); return source; } /** * g_idle_source_new: * * Creates a new idle source. * * The source will not initially be associated with any * [struct@GLib.MainContext] and must be added to one with * [method@GLib.Source.attach] before it will be executed. Note that the * default priority for idle sources is [const@GLib.PRIORITY_DEFAULT_IDLE], as * compared to other sources which have a default priority of * [const@GLib.PRIORITY_DEFAULT]. * * Returns: (transfer full): the newly-created idle source **/ GSource * g_idle_source_new (void) { return idle_source_new (FALSE); } static guint idle_add_full (gint priority, gboolean one_shot, GSourceFunc function, gpointer data, GDestroyNotify notify) { GSource *source; guint id; g_return_val_if_fail (function != NULL, 0); source = idle_source_new (one_shot); if (priority != G_PRIORITY_DEFAULT_IDLE) g_source_set_priority (source, priority); g_source_set_callback (source, function, data, notify); id = g_source_attach (source, NULL); TRACE (GLIB_IDLE_ADD (source, g_main_context_default (), id, priority, function, data)); g_source_unref (source); return id; } /** * g_idle_add_full: (rename-to g_idle_add) * @priority: the priority of the idle source; typically this will be in the * range between [const@GLib.PRIORITY_DEFAULT_IDLE] and * [const@GLib.PRIORITY_HIGH_IDLE] * @function: function to call * @data: data to pass to @function * @notify: (nullable): function to call when the idle is removed * * Adds a function to be called whenever there are no higher priority * events pending. * * If the function returns [const@GLib.SOURCE_REMOVE] it is automatically * removed from the list of event sources and will not be called again. * * See [main loop memory management](main-loop.html#memory-management-of-sources) for details * on how to handle the return value and memory management of @data. * * This internally creates a main loop source using [func@GLib.idle_source_new] * and attaches it to the global [struct@GLib.MainContext] using * [method@GLib.Source.attach], so the callback will be invoked in whichever * thread is running that main context. You can do these steps manually if you * need greater control or to use a custom main context. * * Returns: the ID (greater than 0) of the event source **/ guint g_idle_add_full (gint priority, GSourceFunc function, gpointer data, GDestroyNotify notify) { return idle_add_full (priority, FALSE, function, data, notify); } /** * g_idle_add: * @function: function to call * @data: data to pass to @function * * Adds a function to be called whenever there are no higher priority * events pending to the default main loop. * * The function is given the * default idle priority, [const@GLib.PRIORITY_DEFAULT_IDLE]. If the function * returns [const@GLib.SOURCE_REMOVE] it is automatically removed from the list * of event sources and will not be called again. * * See [main loop memory management](main-loop.html#memory-management-of-sources) for details * on how to handle the return value and memory management of @data. * * This internally creates a main loop source using [func@GLib.idle_source_new] * and attaches it to the global [struct@GLib.MainContext] using * [method@GLib.Source.attach], so the callback will be invoked in whichever * thread is running that main context. You can do these steps manually if you * need greater control or to use a custom main context. * * Returns: the ID (greater than 0) of the event source **/ guint g_idle_add (GSourceFunc function, gpointer data) { return g_idle_add_full (G_PRIORITY_DEFAULT_IDLE, function, data, NULL); } /** * g_idle_add_once: * @function: function to call * @data: data to pass to @function * * Adds a function to be called whenever there are no higher priority * events pending to the default main loop. * * The function is given the * default idle priority, [const@GLib.PRIORITY_DEFAULT_IDLE]. * * The function will only be called once and then the source will be * automatically removed from the main context. * * This function otherwise behaves like [func@GLib.idle_add]. * * Returns: the ID (greater than 0) of the event source * Since: 2.74 */ guint g_idle_add_once (GSourceOnceFunc function, gpointer data) { return idle_add_full (G_PRIORITY_DEFAULT_IDLE, TRUE, (GSourceFunc) function, data, NULL); } /** * g_idle_remove_by_data: * @data: the data for the idle source’s callback. * * Removes the idle function with the given data. * * Returns: true if an idle source was found and removed, false otherwise **/ gboolean g_idle_remove_by_data (gpointer data) { return g_source_remove_by_funcs_user_data (&g_idle_funcs, data); } /** * g_main_context_invoke: * @context: (nullable): a main context, or `NULL` for the global-default * main context * @function: function to call * @data: data to pass to @function * * Invokes a function in such a way that @context is owned during the * invocation of @function. * * If @context is `NULL` then the global-default main context — as * returned by [func@GLib.MainContext.default] — is used. * * If @context is owned by the current thread, @function is called * directly. Otherwise, if @context is the thread-default main context * of the current thread and [method@GLib.MainContext.acquire] succeeds, * then @function is called and [method@GLib.MainContext.release] is called * afterwards. * * In any other case, an idle source is created to call @function and * that source is attached to @context (presumably to be run in another * thread). The idle source is attached with [const@GLib.PRIORITY_DEFAULT] * priority. If you want a different priority, use * [method@GLib.MainContext.invoke_full]. * * Note that, as with normal idle functions, @function should probably return * [const@GLib.SOURCE_REMOVE]. If it returns [const@GLib.SOURCE_CONTINUE], it * will be continuously run in a loop (and may prevent this call from returning). * * Since: 2.28 **/ void g_main_context_invoke (GMainContext *context, GSourceFunc function, gpointer data) { g_main_context_invoke_full (context, G_PRIORITY_DEFAULT, function, data, NULL); } /** * g_main_context_invoke_full: * @context: (nullable): a main context, or `NULL` for the global-default * main context * @priority: the priority at which to run @function * @function: function to call * @data: data to pass to @function * @notify: (nullable): a function to call when @data is no longer in use * * Invokes a function in such a way that @context is owned during the * invocation of @function. * * This function is the same as [method@GLib.MainContext.invoke] except that it * lets you specify the priority in case @function ends up being * scheduled as an idle and also lets you give a [callback@GLib.DestroyNotify] * for @data. * * The @notify function should not assume that it is called from any particular * thread or with any particular context acquired. * * Since: 2.28 **/ void g_main_context_invoke_full (GMainContext *context, gint priority, GSourceFunc function, gpointer data, GDestroyNotify notify) { g_return_if_fail (function != NULL); if (!context) context = g_main_context_default (); if (g_main_context_is_owner (context)) { while (function (data)); if (notify != NULL) notify (data); } else { GMainContext *thread_default; thread_default = g_main_context_get_thread_default (); if (!thread_default) thread_default = g_main_context_default (); if (thread_default == context && g_main_context_acquire (context)) { while (function (data)); g_main_context_release (context); if (notify != NULL) notify (data); } else { GSource *source; source = g_idle_source_new (); g_source_set_priority (source, priority); g_source_set_callback (source, function, data, notify); g_source_attach (source, context); g_source_unref (source); } } } static gpointer glib_worker_main (gpointer data) { while (TRUE) { g_main_context_iteration (glib_worker_context, TRUE); #ifdef G_OS_UNIX if (g_atomic_int_get (&any_unix_signal_pending)) dispatch_unix_signals (); #endif } return NULL; /* worst GCC warning message ever... */ } GMainContext * g_get_worker_context (void) { static gsize initialised; if (g_once_init_enter (&initialised)) { /* mask all signals in the worker thread */ #ifdef G_OS_UNIX sigset_t prev_mask; sigset_t all; sigfillset (&all); pthread_sigmask (SIG_SETMASK, &all, &prev_mask); #endif glib_worker_context = g_main_context_new (); g_thread_new ("gmain", glib_worker_main, NULL); #ifdef G_OS_UNIX pthread_sigmask (SIG_SETMASK, &prev_mask, NULL); #endif g_once_init_leave (&initialised, TRUE); } return glib_worker_context; }