luc14n0/glib
1
0
Fork 0
mirror of https://gitlab.gnome.org/GNOME/glib.git synced 2024-12-25 06:56:14 +01:00
Code Issues Packages Projects Releases Wiki Activity
e18a6a850f
glib/glib/gmain.c
Claudio Saavedra fa45688ff6 gmain: g_main_context_check() can skip updating polled FD sources 
If there is a file descriptor source that has a lower priority
than the one for sources that are going to be dispatched,
all subsequent file descriptor sources (internally sorted by
file descriptor identifier) do not get an update in their GPollRec
and later on wrong sources can be dispatched.

Fix this by first finding the first GPollRec that matches the current
GPollFD, instead of relying on it to be the current one. At
the same time, document the assumptions about the ordering of the
file descriptor records and array and make explicit in the documentation
that the array needs to be passed to g_main_context_check() as it was
received from g_main_context_query().

Added a new test that reproduces the bug by creating two file
descriptor sources and an idle one. Since the first
file descriptor created has a lower identifier and a low priority,
the second one is not dispatched even when it has the same, higher,
priority as the idle source. After fixing this bug, both
higher priority sources are dispatched as expected.

While this patch was written independently, a similar fix for this
bug was first submitted by Eugene M in GNOME/glib!562. Having a
second fix that basically does the same is a reassurance that we
are in the right here.

Fixes #1592
2020-10-26 13:09:19 +00:00

6113 lines
170 KiB
C
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

/* 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
*
* 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 <http://www.gnu.org/licenses/>.
*/
/*
* 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 "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
#ifdef G_OS_UNIX
#include "glib-unix.h"
#include <pthread.h>
#ifdef HAVE_EVENTFD
#include <sys/eventfd.h>
#endif
#endif
#include <signal.h>
#include <sys/types.h>
#include <time.h>
#include <stdlib.h>
#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#endif /* HAVE_SYS_TIME_H */
#ifdef G_OS_UNIX
#include <unistd.h>
#endif /* G_OS_UNIX */
#include <errno.h>
#include <string.h>
#ifdef G_OS_WIN32
#define STRICT
#include <windows.h>
#endif /* G_OS_WIN32 */
#ifdef HAVE_MACH_MACH_TIME_H
#include <mach/mach_time.h>
#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"
/**
* SECTION:main
* @title: The Main Event Loop
* @short_description: manages all available sources of events
*
* The main event loop manages all the available sources of events for
* GLib and GTK+ applications. These events can come from any number of
* different types of sources such as file descriptors (plain files,
* pipes or sockets) and timeouts. New types of event sources can also
* be added using g_source_attach().
*
* To allow multiple independent sets of sources to be handled in
* different threads, each source is associated with a #GMainContext.
* A #GMainContext can only be running in a single thread, but
* sources can be added to it and removed from it from other threads. All
* functions which operate on a #GMainContext or a built-in #GSource are
* thread-safe.
*
* Each event source is assigned a priority. The default priority,
* #G_PRIORITY_DEFAULT, is 0. Values less than 0 denote higher priorities.
* Values greater than 0 denote lower priorities. Events from high priority
* sources are always processed before events from lower priority sources.
*
* Idle functions can also be added, and assigned a priority. These will
* be run whenever no events with a higher priority are ready to be processed.
*
* The #GMainLoop data type represents a main event loop. A GMainLoop is
* created with g_main_loop_new(). After adding the initial event sources,
* g_main_loop_run() is called. This continuously checks for new events from
* each of the event sources and dispatches them. Finally, the processing of
* an event from one of the sources leads to a call to g_main_loop_quit() to
* exit the main loop, and g_main_loop_run() returns.
*
* It is possible to create new instances of #GMainLoop recursively.
* This is often used in GTK+ applications when showing modal dialog
* boxes. Note that event sources are associated with a particular
* #GMainContext, and will be checked and dispatched for all main
* loops associated with that GMainContext.
*
* GTK+ contains wrappers of some of these functions, e.g. gtk_main(),
* gtk_main_quit() and gtk_events_pending().
*
* ## Creating new source types
*
* One of the unusual features of the #GMainLoop functionality
* is that new types of event source can be created and used in
* addition to the builtin type of event source. A new event source
* type is used for handling GDK events. A new source type is created
* by "deriving" from the #GSource structure. The derived type of
* source is represented by a structure that has the #GSource structure
* as a first element, and other elements specific to the new source
* type. To create an instance of the new source type, call
* g_source_new() passing in the size of the derived structure and
* a table of functions. These #GSourceFuncs determine the behavior of
* the new source type.
*
* New source types basically interact with the main context
* in two ways. Their prepare function in #GSourceFuncs can set a timeout
* to determine the maximum amount of time that the main loop will sleep
* before checking the source again. In addition, or as well, the source
* can add file descriptors to the set that the main context checks using
* g_source_add_poll().
*
* ## Customizing the main loop iteration
*
* Single iterations of a #GMainContext can be run with
* g_main_context_iteration(). In some cases, more detailed control
* of exactly how the details of the main loop work is desired, for
* instance, when integrating the #GMainLoop with an external main loop.
* In such cases, you can call the component functions of
* g_main_context_iteration() directly. These functions are
* g_main_context_prepare(), g_main_context_query(),
* g_main_context_check() and g_main_context_dispatch().
*
* ## State of a Main Context # {#mainloop-states}
*
* The operation of these functions can best be seen in terms
* of a state diagram, as shown in this image.
*
* ![](mainloop-states.gif)
*
* On UNIX, the GLib mainloop is incompatible with fork(). Any program
* using the mainloop must either exec() or exit() from the child
* without returning to the mainloop.
*
* ## Memory management of sources # {#mainloop-memory-management}
*
* There are two options for memory management of the user data passed to a
* #GSource to be passed to its callback on invocation. This data is provided
* in calls to g_timeout_add(), g_timeout_add_full(), g_idle_add(), etc. and
* more generally, using g_source_set_callback(). This data is typically an
* object which ‘owns’ the timeout or idle callback, such as a widget or a
* network protocol implementation. In many cases, it is an error for the
* callback to be invoked after this owning object has been destroyed, as that
* results in use of freed memory.
*
* The first, and preferred, option is to store the source ID returned by
* functions such as g_timeout_add() or g_source_attach(), and explicitly
* remove that source from the main context using g_source_remove() when the
* owning object is finalized. This ensures that the callback can only be
* invoked while the object is still alive.
*
* The second option is to hold a strong reference to the object in the
* callback, and to release it in the callback’s #GDestroyNotify. This ensures
* that the object is kept alive until after the source is finalized, which is
* guaranteed to be after it is invoked for the final time. The #GDestroyNotify
* is another callback passed to the ‘full’ variants of #GSource functions (for
* example, g_timeout_add_full()). It is called when the source is finalized,
* and is designed for releasing references like this.
*
* One important caveat of this second approach is that it will keep the object
* alive indefinitely if the main loop is stopped before the #GSource is
* invoked, which may be undesirable.
*/
/* Types */
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
{
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;
GSList *waiters;
volatile gint ref_count;
GHashTable *sources; /* guint -> GSource */
GPtrArray *pending_dispatches;
gint timeout; /* Timeout for current iteration */
guint next_id;
GList *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
{
volatile gint ref_count;
GSourceFunc func;
gpointer data;
GDestroyNotify notify;
};
struct _GMainLoop
{
GMainContext *context;
gboolean is_running; /* (atomic) */
volatile gint ref_count;
};
struct _GTimeoutSource
{
GSource source;
/* Measured in seconds if 'seconds' is TRUE, or milliseconds otherwise. */
guint interval;
gboolean seconds;
};
struct _GChildWatchSource
{
GSource source;
GPid pid;
gint child_status;
#ifdef G_OS_WIN32
GPollFD poll;
#else /* G_OS_WIN32 */
gboolean child_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;
};
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) (((source)->flags & G_HOOK_FLAG_ACTIVE) == 0)
#define SOURCE_BLOCKED(source) (((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 void g_main_context_poll (GMainContext *context,
gint timeout,
gint priority,
GPollFD *fds,
gint 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);
#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);
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 */
G_LOCK_DEFINE_STATIC (main_context_list);
static GSList *main_context_list = NULL;
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: a #GMainContext
*
* Increases the reference count on a #GMainContext object by one.
*
* Returns: the @context that was passed in (since 2.6)
**/
GMainContext *
g_main_context_ref (GMainContext *context)
{
g_return_val_if_fail (context != NULL, NULL);
g_return_val_if_fail (g_atomic_int_get (&context->ref_count) > 0, NULL);
g_atomic_int_inc (&context->ref_count);
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: a #GMainContext
*
* Decreases the reference count on a #GMainContext 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;
g_return_if_fail (context != NULL);
g_return_if_fail (g_atomic_int_get (&context->ref_count) > 0);
if (!g_atomic_int_dec_and_test (&context->ref_count))
return;
G_LOCK (main_context_list);
main_context_list = g_slist_remove (main_context_list, context);
G_UNLOCK (main_context_list);
/* Free pending dispatches */
for (i = 0; i < context->pending_dispatches->len; i++)
g_source_unref_internal (context->pending_dispatches->pdata[i], context, FALSE);
/* 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);
/* 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);
}
for (sl_iter = context->source_lists; sl_iter; sl_iter = sl_iter->next)
{
list = sl_iter->data;
g_slice_free (GSourceList, list);
}
g_list_free (context->source_lists);
g_hash_table_destroy (context->sources);
UNLOCK_CONTEXT (context);
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_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 #GMainContext structure.
*
* Returns: the new #GMainContext
**/
GMainContext *
g_main_context_new (void)
{
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 (NULL, NULL);
context->owner = NULL;
context->waiters = NULL;
context->ref_count = 1;
context->next_id = 1;
context->source_lists = NULL;
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);
G_LOCK (main_context_list);
main_context_list = g_slist_append (main_context_list, context);
#ifdef G_MAIN_POLL_DEBUG
if (_g_main_poll_debug)
g_print ("created context=%p\n", context);
#endif
G_UNLOCK (main_context_list);
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
* g_main_context_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 (&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 ("default context=%p\n", context);
#endif
g_once_init_leave (&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 #GMainContext, or %NULL for the global default 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]-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 context in the main thread. Note that calling this function
* changes the context returned by g_main_context_get_thread_default(),
* not the one returned by g_main_context_default(), so it does not affect
* the context used by functions like g_idle_add().
*
* Normally you would call this function shortly after creating a new
* thread, passing it a #GMainContext which will be run by a
* #GMainLoop 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 g_main_context_pop_thread_default(), assuming you want the
* new #GMainContext 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 #GMainContext inside a
* g_main_context_push_thread_default() / g_main_context_pop_thread_default()
* pair, otherwise threads that are re-used will end up never explicitly
* releasing the #GMainContext 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
* g_main_context_push_thread_default() /
* g_main_context_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. Eg,
* 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 #GMainContext object, or %NULL
*
* 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 #GMainContext 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
* g_main_context_ref_thread_default() to get a #GMainContext to add
* their #GSources 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
* g_main_context_ref_thread_default() instead.
*
* Returns: (transfer none) (nullable): the thread-default #GMainContext, or
* %NULL if the thread-default context is the global default 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 the thread-default #GMainContext for this thread, as with
* g_main_context_get_thread_default(), but also adds a reference to
* it with g_main_context_ref(). In addition, unlike
* g_main_context_get_thread_default(), if the thread-default context
* is the global default context, this will return that #GMainContext
* (with a ref added to it) rather than returning %NULL.
*
* Returns: (transfer full): the thread-default #GMainContext. Unref
* with g_main_context_unref() when you are done with it.
*
* 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 sources behavior.
* @struct_size: size of the #GSource structure to create.
*
* Creates a new #GSource structure. The size is specified to
* allow creating structures derived from #GSource that contain
* additional data. The size passed in must be at least
* `sizeof (GSource)`.
*
* The source will not initially be associated with any #GMainContext
* and must be added to one with g_source_attach() before it will be
* executed.
*
* Returns: the newly-created #GSource.
**/
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;
source->ref_count = 1;
source->priority = G_PRIORITY_DEFAULT;
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 #GSource to set the dispose function on
* @dispose: #GSourceDisposeFunc to set on the source
*
* Set @dispose as dispose function on @source. @dispose will be called once
* the reference count of @source reaches 0 but before any of the state of the
* source is freed, especially before the finalize function is called.
*
* This means that at this point @source is still a valid #GSource 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 anymore.
*
* This should only ever be called from #GSource implementations.
*
* Since: 2.64
**/
void
g_source_set_dispose_function (GSource *source,
GSourceDisposeFunc dispose)
{
g_return_if_fail (source != NULL);
g_return_if_fail (source->priv->dispose == NULL);
g_return_if_fail (g_atomic_int_get (&source->ref_count) > 0);
source->priv->dispose = dispose;
}
/* 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;
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, *last;
GSourceList *source_list;
last = NULL;
for (iter = context->source_lists; iter != NULL; last = 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->priority = priority;
context->source_lists = g_list_insert_before (context->source_lists,
iter,
source_list);
return source_list;
}
}
if (!create)
return NULL;
source_list = g_slice_new0 (GSourceList);
source_list->priority = priority;
if (!last)
context->source_lists = g_list_append (NULL, source_list);
else
{
/* This just appends source_list to the end of
* context->source_lists without having to walk the list again.
*/
last = g_list_append (last, source_list);
(void) last;
}
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)
{
context->source_lists = g_list_remove (context->source_lists, source_list);
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, GUINT_TO_POINTER (id)));
source->context = context;
source->source_id = id;
g_source_ref (source);
g_hash_table_insert (context->sources, GUINT_TO_POINTER (id), source);
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->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 #GSource
* @context: (nullable): a #GMainContext (if %NULL, the default context will be used)
*
* Adds a #GSource to a @context so that it will be executed within
* that context. Remove it by calling g_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
* #GMainContext.
**/
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;
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);
}
/**
* g_source_destroy:
* @source: a #GSource
*
* Removes a source from its #GMainContext, if any, and mark 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 #GSource: if you still hold a reference, use
* g_source_unref() to drop it.
*
* This function is safe to call from any thread, regardless of which thread
* the #GMainContext is running in.
*/
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->context;
if (context)
g_source_destroy_internal (source, context, FALSE);
else
source->flags &= ~G_HOOK_FLAG_ACTIVE;
}
/**
* g_source_get_id:
* @source: a #GSource
*
* 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 g_main_context_find_source_by_id().
*
* You can only call this function while the source is associated to a
* #GMainContext instance; calling this function before g_source_attach()
* or after g_source_destroy() yields undefined behavior. The ID returned
* is unique within the #GMainContext instance passed to g_source_attach().
*
* Returns: the ID (greater than 0) for the source
**/
guint
g_source_get_id (GSource *source)
{
guint result;
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);
LOCK_CONTEXT (source->context);
result = source->source_id;
UNLOCK_CONTEXT (source->context);
return result;
}
/**
* g_source_get_context:
* @source: a #GSource
*
* Gets the #GMainContext with which the source is associated.
*
* You can call this on a source that has been destroyed, provided
* that the #GMainContext it was attached to still exists (in which
* case it will return that #GMainContext). In particular, you can
* always call this function on the source returned from
* g_main_current_source(). But calling this function on a source
* whose #GMainContext has been destroyed is an error.
*
* Returns: (transfer none) (nullable): the #GMainContext 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_add_poll:
* @source:a #GSource
* @fd: a #GPollFD 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 g_source_new() to add an
* event source. The event source's check function will typically test
* the @revents field in the #GPollFD struct and return %TRUE if events need
* to be processed.
*
* This API is only intended to be used by implementations of #GSource.
* Do not call this API on a #GSource 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->context;
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_source_remove_poll:
* @source:a #GSource
* @fd: a #GPollFD structure previously passed to g_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 #GSource.
* Do not call this API on a #GSource 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->context;
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_source_add_child_source:
* @source:a #GSource
* @child_source: a second #GSource that @source should "poll"
*
* Adds @child_source to @source as a "polled" source; when @source is
* added to a #GMainContext, @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. (@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).
*
* @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 #GSource.
* Do not call this API on a #GSource 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->context;
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);
if (context)
{
g_source_attach_unlocked (child_source, context, TRUE);
UNLOCK_CONTEXT (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 #GSource
* @child_source: a #GSource previously passed to
* g_source_add_child_source().
*
* Detaches @child_source from @source and destroys it.
*
* This API is only intended to be used by implementations of #GSource.
* Do not call this API on a #GSource 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->context;
if (context)
LOCK_CONTEXT (context);
g_child_source_remove_internal (child_source, context);
if (context)
UNLOCK_CONTEXT (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 refcounted callback
* "object". This is used internally. Note that calling
* g_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->context;
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);
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, or %NULL.
*
* 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 G_SOURCE_FUNC() to avoid warnings about
* incompatible function types.
*
* See [memory management of sources][mainloop-memory-management] 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 g_idle_add() or g_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.
**/
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 #GSource
* @funcs: the new #GSourceFuncs
*
* Sets the source functions (can be used to override
* default implementations) of an unattached 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, source->context);
}
source->priority = priority;
if (context)
{
source_add_to_context (source, 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 #GSource
* @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->context;
if (context)
LOCK_CONTEXT (context);
g_source_set_priority_unlocked (source, context, priority);
if (context)
UNLOCK_CONTEXT (context);
}
/**
* g_source_get_priority:
* @source: a #GSource
*
* 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 #GSource
* @ready_time: the monotonic time at which the source will be ready,
* 0 for "immediately", -1 for "never"
*
* Sets a #GSource 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 #GSource which has already been
* destroyed with g_source_destroy().
*
* This API is only intended to be used by implementations of #GSource.
* Do not call this API on a #GSource 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->context;
if (context)
LOCK_CONTEXT (context);
if (source->priv->ready_time == ready_time)
{
if (context)
UNLOCK_CONTEXT (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_source_get_ready_time:
* @source: a #GSource
*
* Gets the "ready time" of @source, as set by
* g_source_set_ready_time().
*
* Any time before the current monotonic time (including 0) 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 #GSource
* @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->context;
if (context)
LOCK_CONTEXT (context);
if (can_recurse)
source->flags |= G_SOURCE_CAN_RECURSE;
else
source->flags &= ~G_SOURCE_CAN_RECURSE;
if (context)
UNLOCK_CONTEXT (context);
}
/**
* g_source_get_can_recurse:
* @source: a #GSource
*
* Checks whether a source is allowed to be called recursively.
* see g_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 (source->flags & G_SOURCE_CAN_RECURSE) != 0;
}
/**
* g_source_set_name:
* @source: a #GSource
* @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" or whatever it is.
*
* 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 #GSourceFuncs
* 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 g_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.
*
* Since: 2.26
**/
void
g_source_set_name (GSource *source,
const char *name)
{
GMainContext *context;
g_return_if_fail (source != NULL);
g_return_if_fail (g_atomic_int_get (&source->ref_count) > 0);
context = source->context;
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.
*/
g_free (source->name);
source->name = g_strdup (name);
if (context)
UNLOCK_CONTEXT (context);
}
/**
* g_source_get_name:
* @source: a #GSource
*
* Gets a name for the source, used in debugging and profiling. The
* name may be #NULL if it has never been set with g_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 #GSource 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 g_idle_add(), g_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 g_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 #GSource
*
* Increases the reference count on a source by one.
*
* Returns: @source
**/
GSource *
g_source_ref (GSource *source)
{
g_return_val_if_fail (source != NULL, NULL);
/* We allow ref_count == 0 here to allow the dispose function to resurrect
* the GSource if needed */
g_return_val_if_fail (g_atomic_int_get (&source->ref_count) >= 0, NULL);
g_atomic_int_inc (&source->ref_count);
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;
g_return_if_fail (source != NULL);
if (!have_lock && context)
LOCK_CONTEXT (context);
if (g_atomic_int_dec_and_test (&source->ref_count))
{
/* If there's a dispose function, call this first */
if (source->priv->dispose)
{
/* Temporarily increase the ref count again so that GSource methods
* can be called from dispose(). */
g_atomic_int_inc (&source->ref_count);
if (context)
UNLOCK_CONTEXT (context);
source->priv->dispose (source);
if (context)
LOCK_CONTEXT (context);
/* Now the reference count might be bigger than 0 again, in which
* case we simply return from here before freeing the source */
if (!g_atomic_int_dec_and_test (&source->ref_count))
{
if (!have_lock && context)
UNLOCK_CONTEXT (context);
return;
}
}
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, GUINT_TO_POINTER (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);
}
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 #GSource
*
* 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)
{
g_return_if_fail (source != NULL);
g_return_if_fail (g_atomic_int_get (&source->ref_count) > 0);
g_source_unref_internal (source, source->context, FALSE);
}
/**
* g_main_context_find_source_by_id:
* @context: (nullable): a #GMainContext (if %NULL, the default context will be used)
* @source_id: the source ID, as returned by g_source_get_id().
*
* Finds a #GSource 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 g_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 #GSource
**/
GSource *
g_main_context_find_source_by_id (GMainContext *context,
guint source_id)
{
GSource *source;
g_return_val_if_fail (source_id > 0, NULL);
if (context == NULL)
context = g_main_context_default ();
LOCK_CONTEXT (context);
source = g_hash_table_lookup (context->sources, GUINT_TO_POINTER (source_id));
UNLOCK_CONTEXT (context);
if (source && SOURCE_DESTROYED (source))
source = NULL;
return source;
}
/**
* g_main_context_find_source_by_funcs_user_data:
* @context: (nullable): a #GMainContext (if %NULL, the default context will be used).
* @funcs: the @source_funcs passed to g_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): 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: a #GMainContext
* @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): 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 g_source_destroy() for sources added to a non-default main context.
*
* The ID of a #GSource is given by g_source_get_id(), or will be
* returned by the functions g_source_attach(), g_idle_add(),
* g_idle_add_full(), g_timeout_add(), g_timeout_add_full(),
* g_child_watch_add(), g_child_watch_add_full(), g_io_add_watch(), and
* g_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 g_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: For historical reasons, this function always returns %TRUE
**/
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.
**/
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 g_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.
**/
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 #GSource ID.
*
* @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 #GSource
* @fd: the fd 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 g_source_remove_unix_fd() or
* g_source_modify_unix_fd().
*
* It is not necessary to remove the fd before destroying the source; it
* will be cleaned up automatically.
*
* This API is only intended to be used by implementations of #GSource.
* Do not call this API on a #GSource 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->context;
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);
}
return poll_fd;
}
/**
* g_source_modify_unix_fd:
* @source: a #GSource
* @tag: (not nullable): the tag from g_source_add_unix_fd()
* @new_events: the new event mask to watch
*
* Updates the event mask to watch for the fd identified by @tag.
*
* @tag is the tag returned from g_source_add_unix_fd().
*
* If you want to remove a fd, don't set its event mask to zero.
* Instead, call g_source_remove_unix_fd().
*
* This API is only intended to be used by implementations of #GSource.
* Do not call this API on a #GSource 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->context;
poll_fd = tag;
poll_fd->events = new_events;
if (context)
g_main_context_wakeup (context);
}
/**
* g_source_remove_unix_fd:
* @source: a #GSource
* @tag: (not nullable): the tag from g_source_add_unix_fd()
*
* Reverses the effect of a previous call to g_source_add_unix_fd().
*
* You only need to call this if you want to remove an fd 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 #GSource.
* Do not call this API on a #GSource 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->context;
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_free (poll_fd);
}
/**
* g_source_query_unix_fd:
* @source: a #GSource
* @tag: (not nullable): the tag from g_source_add_unix_fd()
*
* Queries the events reported for the fd 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 #GSource.
* Do not call this API on a #GSource that you did not create.
*
* As the name suggests, this function is not available on Windows.
*
* Returns: the conditions reported on the fd
*
* 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: #GTimeVal structure in which to store current time.
*
* Equivalent to the UNIX gettimeofday() function, but portable.
*
* You may find g_get_real_time() to be more convenient.
*
* Deprecated: 2.62: #GTimeVal is not year-2038-safe. Use g_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 call is functionally equivalent to g_get_current_time() except
* that the return value is often more convenient than dealing with a
* #GTimeVal.
*
* You should only use this call if you are actually interested in the real
* wall-clock time. g_get_monotonic_time() is probably more useful for
* measuring intervals.
*
* Returns: the number of microseconds since January 1, 1970 UTC.
*
* 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() 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
* g_main_context_dispatch() on any #GMainContext in the current thread.
* That is, when called from the toplevel, it gives 0. When
* called from within a callback from g_main_context_iteration()
* (or g_main_loop_run(), etc.) it returns 1. When called from within
* a callback to a recursive call to g_main_context_iteration(),
* it returns 2. And so forth.
*
* This function is useful in a situation like the following:
* Imagine an extremely simple "garbage collected" system.
*
* |[<!-- language="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 g_main_depth()
*
* |[<!-- language="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 g_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 g_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.
*
* Since: 2.12
*/
GSource *
g_main_current_source (void)
{
GMainDispatch *dispatch = get_dispatch ();
return dispatch->source;
}
/**
* g_source_is_destroyed:
* @source: a #GSource
*
* 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.
*
* |[<!-- language="C" -->
* static gboolean
* idle_callback (gpointer data)
* {
* SomeWidget *self = data;
*
* GDK_THREADS_ENTER ();
* // do stuff with self
* self->idle_id = 0;
* GDK_THREADS_LEAVE ();
*
* return G_SOURCE_REMOVE;
* }
*
* static void
* some_widget_do_stuff_later (SomeWidget *self)
* {
* self->idle_id = g_idle_add (idle_callback, self);
* }
*
* static void
* some_widget_finalize (GObject *object)
* {
* SomeWidget *self = SOME_WIDGET (object);
*
* if (self->idle_id)
* g_source_remove (self->idle_id);
*
* 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.
*
* |[<!-- language="C" -->
* static gboolean
* idle_callback (gpointer data)
* {
* SomeWidget *self = data;
*
* GDK_THREADS_ENTER ();
* if (!g_source_is_destroyed (g_main_current_source ()))
* {
* // do stuff with self
* }
* GDK_THREADS_LEAVE ();
*
* return FALSE;
* }
* ]|
*
* Calls to this function from a thread other than the one acquired by the
* #GMainContext the #GSource 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
*
* 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)
{
GSList *tmp_list;
g_return_if_fail (!SOURCE_BLOCKED (source));
source->flags |= G_SOURCE_BLOCKED;
if (source->context)
{
tmp_list = source->poll_fds;
while (tmp_list)
{
g_main_context_remove_poll_unlocked (source->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 (source->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);
tmp_list = tmp_list->next;
}
}
}
/* HOLDS: source->context's lock */
static void
unblock_source (GSource *source)
{
GSList *tmp_list;
g_return_if_fail (SOURCE_BLOCKED (source)); /* Source already unblocked */
g_return_if_fail (!SOURCE_DESTROYED (source));
source->flags &= ~G_SOURCE_BLOCKED;
tmp_list = source->poll_fds;
while (tmp_list)
{
g_main_context_add_poll_unlocked (source->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 (source->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);
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);
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 ((source->flags & G_SOURCE_CAN_RECURSE) == 0)
block_source (source);
was_in_call = source->flags & G_HOOK_FLAG_IN_CALL;
source->flags |= 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)
source->flags &= ~G_HOOK_FLAG_IN_CALL;
if (SOURCE_BLOCKED (source) && !SOURCE_DESTROYED (source))
unblock_source (source);
/* 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: a #GMainContext
*
* 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 g_main_context_release()
* is called as many times as g_main_context_acquire().
*
* You must be the owner of a context before you
* can call g_main_context_prepare(), g_main_context_query(),
* g_main_context_check(), g_main_context_dispatch().
*
* Returns: %TRUE if the operation succeeded, and
* this thread is now the owner of @context.
**/
gboolean
g_main_context_acquire (GMainContext *context)
{
gboolean result = FALSE;
GThread *self = G_THREAD_SELF;
if (context == NULL)
context = g_main_context_default ();
LOCK_CONTEXT (context);
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++;
result = TRUE;
}
else
{
TRACE (GLIB_MAIN_CONTEXT_ACQUIRE (context, FALSE /* failure */));
}
UNLOCK_CONTEXT (context);
return result;
}
/**
* g_main_context_release:
* @context: a #GMainContext
*
* Releases ownership of a context previously acquired by this thread
* with g_main_context_acquire(). If the context was acquired multiple
* times, the ownership will be released only when g_main_context_release()
* is called as many times as it was acquired.
**/
void
g_main_context_release (GMainContext *context)
{
if (context == NULL)
context = g_main_context_default ();
LOCK_CONTEXT (context);
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);
}
}
UNLOCK_CONTEXT (context);
}
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;
if (context == NULL)
context = g_main_context_default ();
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: a #GMainContext
* @cond: a condition variable
* @mutex: a mutex, currently held
*
* Tries to become the owner of the specified context,
* as with g_main_context_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 the operation succeeded, and
* this thread is now the owner of @context.
* Deprecated: 2.58: Use g_main_context_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: a #GMainContext
* @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 g_main_context_query ().
*
* You must have successfully acquired the context with
* g_main_context_acquire() before you may call this function.
*
* Returns: %TRUE if some source is ready to be dispatched
* prior to polling.
**/
gboolean
g_main_context_prepare (GMainContext *context,
gint *priority)
{
guint i;
gint n_ready = 0;
gint current_priority = G_MAXINT;
GSource *source;
GSourceIter iter;
if (context == NULL)
context = g_main_context_default ();
LOCK_CONTEXT (context);
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.");
UNLOCK_CONTEXT (context);
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, &current_time);
UNLOCK_CONTEXT (context);
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 = -1;
g_source_iter_init (&iter, context, TRUE);
while (g_source_iter_next (&iter, &source))
{
gint source_timeout = -1;
if (SOURCE_DESTROYED (source) || SOURCE_BLOCKED (source))
continue;
if ((n_ready > 0) && (source->priority > current_priority))
break;
if (!(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;
context->in_check_or_prepare++;
UNLOCK_CONTEXT (context);
begin_time_nsec = G_TRACE_CURRENT_TIME;
result = (* prepare) (source, &source_timeout);
TRACE (GLIB_MAIN_AFTER_PREPARE (source, prepare, source_timeout));
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
{
source_timeout = -1;
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 = 0;
result = TRUE;
}
else
{
gint64 timeout;
/* rounding down will lead to spinning, so always round up */
timeout = (source->priv->ready_time - context->time + 999) / 1000;
if (source_timeout < 0 || timeout < source_timeout)
source_timeout = MIN (timeout, G_MAXINT);
}
}
if (result)
{
GSource *ready_source = source;
while (ready_source)
{
ready_source->flags |= G_SOURCE_READY;
ready_source = ready_source->priv->parent_source;
}
}
}
if (source->flags & G_SOURCE_READY)
{
n_ready++;
current_priority = source->priority;
context->timeout = 0;
}
if (source_timeout >= 0)
{
if (context->timeout < 0)
context->timeout = source_timeout;
else
context->timeout = MIN (context->timeout, source_timeout);
}
}
g_source_iter_clear (&iter);
TRACE (GLIB_MAIN_CONTEXT_AFTER_PREPARE (context, current_priority, n_ready));
UNLOCK_CONTEXT (context);
if (priority)
*priority = current_priority;
return (n_ready > 0);
}
/**
* g_main_context_query:
* @context: a #GMainContext
* @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 #GPollFD 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 g_main_context_check(), as this function relies
* on assumptions made when the array is filled.
*
* You must have successfully acquired the context with
* g_main_context_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,
GPollFD *fds,
gint n_fds)
{
gint n_poll;
GPollRec *pollrec, *lastpollrec;
gushort events;
LOCK_CONTEXT (context);
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)
{
*timeout = context->timeout;
if (*timeout != 0)
context->time_is_fresh = FALSE;
}
TRACE (GLIB_MAIN_CONTEXT_AFTER_QUERY (context, context->timeout,
fds, n_poll));
UNLOCK_CONTEXT (context);
return n_poll;
}
/**
* g_main_context_check:
* @context: a #GMainContext
* @max_priority: the maximum numerical priority of sources to check
* @fds: (array length=n_fds): array of #GPollFD's that was passed to
* the last call to g_main_context_query()
* @n_fds: return value of g_main_context_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
* g_main_context_query(), as this functions relies on assumptions
* on how @fds is filled.
*
* You must have successfully acquired the context with
* g_main_context_acquire() before you may call this function.
*
* Returns: %TRUE if some sources are ready to be dispatched.
**/
gboolean
g_main_context_check (GMainContext *context,
gint max_priority,
GPollFD *fds,
gint n_fds)
{
GSource *source;
GSourceIter iter;
GPollRec *pollrec;
gint n_ready = 0;
gint i;
LOCK_CONTEXT (context);
if (context->in_check_or_prepare)
{
g_warning ("g_main_context_check() called recursively from within a source's check() or "
"prepare() member.");
UNLOCK_CONTEXT (context);
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));
UNLOCK_CONTEXT (context);
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 (!(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)
{
ready_source->flags |= G_SOURCE_READY;
ready_source = ready_source->priv->parent_source;
}
}
}
if (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));
UNLOCK_CONTEXT (context);
return n_ready > 0;
}
/**
* g_main_context_dispatch:
* @context: a #GMainContext
*
* Dispatches all pending sources.
*
* You must have successfully acquired the context with
* g_main_context_acquire() before you may call this function.
**/
void
g_main_context_dispatch (GMainContext *context)
{
LOCK_CONTEXT (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));
UNLOCK_CONTEXT (context);
}
/* HOLDS context lock */
static gboolean
g_main_context_iterate (GMainContext *context,
gboolean block,
gboolean dispatch,
GThread *self)
{
gint max_priority;
gint timeout;
gboolean some_ready;
gint nfds, allocated_nfds;
GPollFD *fds = NULL;
gint64 begin_time_nsec G_GNUC_UNUSED;
UNLOCK_CONTEXT (context);
begin_time_nsec = G_TRACE_CURRENT_TIME;
if (!g_main_context_acquire (context))
{
gboolean got_ownership;
LOCK_CONTEXT (context);
if (!block)
return FALSE;
got_ownership = g_main_context_wait_internal (context,
&context->cond,
&context->mutex);
if (!got_ownership)
return FALSE;
}
else
LOCK_CONTEXT (context);
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;
UNLOCK_CONTEXT (context);
g_main_context_prepare (context, &max_priority);
while ((nfds = g_main_context_query (context, max_priority, &timeout, fds,
allocated_nfds)) > allocated_nfds)
{
LOCK_CONTEXT (context);
g_free (fds);
context->cached_poll_array_size = allocated_nfds = nfds;
context->cached_poll_array = fds = g_new (GPollFD, nfds);
UNLOCK_CONTEXT (context);
}
if (!block)
timeout = 0;
g_main_context_poll (context, timeout, max_priority, fds, nfds);
some_ready = g_main_context_check (context, max_priority, fds, nfds);
if (dispatch)
g_main_context_dispatch (context);
g_main_context_release (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");
LOCK_CONTEXT (context);
return some_ready;
}
/**
* g_main_context_pending:
* @context: (nullable): a #GMainContext (if %NULL, the default context will be used)
*
* Checks if any sources have pending events for the given context.
*
* Returns: %TRUE if events are pending.
**/
gboolean
g_main_context_pending (GMainContext *context)
{
gboolean retval;
if (!context)
context = g_main_context_default();
LOCK_CONTEXT (context);
retval = g_main_context_iterate (context, FALSE, FALSE, G_THREAD_SELF);
UNLOCK_CONTEXT (context);
return retval;
}
/**
* g_main_context_iteration:
* @context: (nullable): a #GMainContext (if %NULL, the default 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
* sources are not waited to become ready, only those highest priority
* events sources will be dispatched (if any), that are ready at this
* given moment without further waiting.
*
* Note that even when @may_block is %TRUE, it is still possible for
* g_main_context_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.
**/
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 (context, may_block, TRUE, G_THREAD_SELF);
UNLOCK_CONTEXT (context);
return retval;
}
/**
* g_main_loop_new:
* @context: (nullable): a #GMainContext (if %NULL, the default context will be used).
* @is_running: set to %TRUE to indicate that the loop is running. This
* is not very important since calling g_main_loop_run() will set this to
* %TRUE anyway.
*
* Creates a new #GMainLoop structure.
*
* Returns: a new #GMainLoop.
**/
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 #GMainLoop
*
* Increases the reference count on a #GMainLoop 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 #GMainLoop
*
* Decreases the reference count on a #GMainLoop object by one. If
* the result is zero, free the loop and free all associated memory.
**/
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 #GMainLoop
*
* Runs a main loop until g_main_loop_quit() is called on the loop.
* If this is called for the thread of the loop's #GMainContext,
* 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);
if (!g_main_context_acquire (loop->context))
{
gboolean got_ownership = FALSE;
/* Another thread owns this context */
LOCK_CONTEXT (loop->context);
g_atomic_int_inc (&loop->ref_count);
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))
{
UNLOCK_CONTEXT (loop->context);
if (got_ownership)
g_main_context_release (loop->context);
g_main_loop_unref (loop);
return;
}
g_assert (got_ownership);
}
else
LOCK_CONTEXT (loop->context);
if (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.");
return;
}
g_atomic_int_inc (&loop->ref_count);
g_atomic_int_set (&loop->is_running, TRUE);
while (g_atomic_int_get (&loop->is_running))
g_main_context_iterate (loop->context, TRUE, TRUE, self);
UNLOCK_CONTEXT (loop->context);
g_main_context_release (loop->context);
g_main_loop_unref (loop);
}
/**
* g_main_loop_quit:
* @loop: a #GMainLoop
*
* Stops a #GMainLoop from running. Any calls to g_main_loop_run()
* for the loop will return.
*
* Note that sources that have already been dispatched when
* g_main_loop_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 #GMainLoop.
*
* Checks to see if the main loop is currently being run via g_main_loop_run().
*
* Returns: %TRUE if the mainloop is currently being run.
**/
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 #GMainLoop.
*
* Returns the #GMainContext of @loop.
*
* Returns: (transfer none): the #GMainContext 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 (GMainContext *context,
gint timeout,
gint priority,
GPollFD *fds,
gint n_fds)
{
#ifdef G_MAIN_POLL_DEBUG
GTimer *poll_timer;
GPollRec *pollrec;
gint i;
#endif
GPollFunc poll_func;
if (n_fds || timeout != 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=%d\n",
context, n_fds, timeout);
poll_timer = g_timer_new ();
}
#endif
LOCK_CONTEXT (context);
poll_func = context->poll_func;
UNLOCK_CONTEXT (context);
ret = (*poll_func) (fds, n_fds, timeout);
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)
{
LOCK_CONTEXT (context);
g_print ("g_main_poll(%d) timeout: %d - elapsed %12.10f seconds",
n_fds,
timeout,
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");
UNLOCK_CONTEXT (context);
}
#endif
} /* if (n_fds || timeout != 0) */
}
/**
* g_main_context_add_poll:
* @context: (nullable): a #GMainContext (or %NULL for the default context)
* @fd: a #GPollFD 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 g_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() */
g_wakeup_signal (context->wakeup);
}
/**
* g_main_context_remove_poll:
* @context:a #GMainContext
* @fd: a #GPollFD descriptor previously added with g_main_context_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 #GSource
* @timeval: #GTimeVal structure in which to store current time.
*
* This function ignores @source and is otherwise the same as
* g_get_current_time().
*
* Deprecated: 2.28: use g_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 #GSource
*
* Gets the time to be used when checking this source. The advantage of
* calling this function over calling g_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 g_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);
g_return_val_if_fail (source->context != NULL, 0);
context = source->context;
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);
return result;
}
/**
* g_main_context_set_poll_func:
* @context: a #GMainContext
* @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() 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: a #GMainContext
*
* Gets the poll function set by g_main_context_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: a #GMainContext
*
* If @context is currently blocking in g_main_context_iteration()
* waiting for a source to become ready, cause it to stop blocking
* and return. Otherwise, cause the next invocation of
* g_main_context_iteration() to return without blocking.
*
* This API is useful for low-level control over #GMainContext; for
* example, integrating it with main loop implementations such as
* #GMainLoop.
*
* Another related use for this function is when implementing a main
* loop with a termination condition, computed from multiple threads:
*
* |[<!-- language="C" -->
* #define NUM_TASKS 10
* static volatile gint tasks_remaining = NUM_TASKS;
* ...
*
* while (g_atomic_int_get (&tasks_remaining) != 0)
* g_main_context_iteration (NULL, TRUE);
* ]|
*
* Then in a thread:
* |[<!-- language="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: a #GMainContext
*
* Determines whether this thread holds the (recursive)
* ownership of this #GMainContext. 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.
*
* 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;
}
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;
}
/**
* g_timeout_source_new:
* @interval: the timeout interval in milliseconds.
*
* Creates a new timeout source.
*
* The source will not initially be associated with any #GMainContext
* and must be added to one with g_source_attach() before it will be
* executed.
*
* The interval given is in terms of monotonic time, not wall clock
* time. See g_get_monotonic_time().
*
* Returns: the newly-created timeout source
**/
GSource *
g_timeout_source_new (guint interval)
{
GSource *source = g_source_new (&g_timeout_funcs, sizeof (GTimeoutSource));
GTimeoutSource *timeout_source = (GTimeoutSource *)source;
timeout_source->interval = interval;
g_timeout_set_expiration (timeout_source, g_get_monotonic_time ());
return source;
}
/**
* 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 #GMainContext
* and must be added to one with g_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 g_get_monotonic_time().
*
* Returns: the newly-created timeout source
*
* Since: 2.14
**/
GSource *
g_timeout_source_new_seconds (guint interval)
{
GSource *source = g_source_new (&g_timeout_funcs, sizeof (GTimeoutSource));
GTimeoutSource *timeout_source = (GTimeoutSource *)source;
timeout_source->interval = interval;
timeout_source->seconds = TRUE;
g_timeout_set_expiration (timeout_source, g_get_monotonic_time ());
return source;
}
/**
* g_timeout_add_full: (rename-to g_timeout_add)
* @priority: the priority of the timeout source. Typically this will be in
* the range between #G_PRIORITY_DEFAULT and #G_PRIORITY_HIGH.
* @interval: the time between calls to the function, in milliseconds
* (1/1000ths of a second)
* @function: function to call
* @data: data to pass to @function
* @notify: (nullable): function to call when the timeout is removed, or %NULL
*
* Sets a function to be called at regular intervals, with the given
* priority. The function is called repeatedly until it returns
* %FALSE, 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 [memory management of sources][mainloop-memory-management] for details
* on how to handle the return value and memory management of @data.
*
* This internally creates a main loop source using g_timeout_source_new()
* and attaches it to the global #GMainContext using g_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 g_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)
{
GSource *source;
guint id;
g_return_val_if_fail (function != NULL, 0);
source = g_timeout_source_new (interval);
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:
* @interval: the time between calls to the function, in milliseconds
* (1/1000ths of a second)
* @function: function to call
* @data: data to pass to @function
*
* Sets a function to be called at regular intervals, with the default
* priority, #G_PRIORITY_DEFAULT. The function is called repeatedly
* until it returns %FALSE, 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 [memory management of sources][mainloop-memory-management] 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
* g_timeout_add_seconds() function; this function allows for more
* optimizations and more efficient system power usage.
*
* This internally creates a main loop source using g_timeout_source_new()
* and attaches it to the global #GMainContext using g_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 g_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_seconds_full: (rename-to g_timeout_add_seconds)
* @priority: the priority of the timeout source. Typically this will be in
* the range between #G_PRIORITY_DEFAULT and #G_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, or %NULL
*
* Sets a function to be called at regular intervals, with @priority.
* The function is called repeatedly until it returns %FALSE, at which
* point the timeout is automatically destroyed and the function will
* not be called again.
*
* Unlike g_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 [memory management of sources][mainloop-memory-management] for details
* on how to handle the return value and memory management of @data.
*
* If you want timing more precise than whole seconds, use g_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 g_timeout_add_seconds() is preferred over g_timeout_add().
*
* This internally creates a main loop source using
* g_timeout_source_new_seconds() and attaches it to the main loop context
* using g_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 g_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)
{
GSource *source;
guint id;
g_return_val_if_fail (function != NULL, 0);
source = g_timeout_source_new_seconds (interval);
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);
g_source_unref (source);
return id;
}
/**
* 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, #G_PRIORITY_DEFAULT. The function is called repeatedly until
* it returns %FALSE, at which point the timeout is automatically destroyed
* and the function will not be called again.
*
* This internally creates a main loop source using
* g_timeout_source_new_seconds() and attaches it to the main loop context
* using g_source_attach(). You can do these steps manually if you need
* greater control. Also see g_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 g_timeout_add() instead.
*
* See [memory management of sources][mainloop-memory-management] 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 g_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);
}
/* Child watch functions */
#ifdef G_OS_WIN32
static gboolean
g_child_watch_prepare (GSource *source,
gint *timeout)
{
*timeout = -1;
return FALSE;
}
static gboolean
g_child_watch_check (GSource *source)
{
GChildWatchSource *child_watch_source;
gboolean child_exited;
child_watch_source = (GChildWatchSource *) source;
child_exited = child_watch_source->poll.revents & G_IO_IN;
if (child_exited)
{
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);
child_watch_source->child_status = -1;
}
else
child_watch_source->child_status = child_status;
}
return child_exited;
}
static void
g_child_watch_finalize (GSource *source)
{
}
#else /* 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 we hold the
* main_context_list lock
*
* 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.
*/
G_LOCK(main_context_list);
context = source->context;
if (context)
g_wakeup_signal (context->wakeup);
G_UNLOCK(main_context_list);
}
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_get (&source->child_exited))
{
pid_t pid;
do
{
g_assert (source->pid > 0);
pid = waitpid (source->pid, &source->child_status, WNOHANG);
if (pid > 0)
{
g_atomic_int_set (&source->child_exited, TRUE);
wake_source ((GSource *) source);
}
else if (pid == -1 && errno == ECHILD)
{
g_warning ("GChildWatchSource: Exit status of a child process was requested but ECHILD was received by waitpid(). See the documentation of g_child_watch_source_new() for possible causes.");
source->child_status = 0;
g_atomic_int_set (&source->child_exited, TRUE);
wake_source ((GSource *) source);
}
}
while (pid == -1 && errno == EINTR);
}
}
}
/* 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_child_watch_prepare (GSource *source,
gint *timeout)
{
GChildWatchSource *child_watch_source;
child_watch_source = (GChildWatchSource *) source;
return g_atomic_int_get (&child_watch_source->child_exited);
}
static gboolean
g_child_watch_check (GSource *source)
{
GChildWatchSource *child_watch_source;
child_watch_source = (GChildWatchSource *) source;
return g_atomic_int_get (&child_watch_source->child_exited);
}
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
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_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);
}
static void
g_child_watch_finalize (GSource *source)
{
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 */
static gboolean
g_child_watch_dispatch (GSource *source,
GSourceFunc callback,
gpointer user_data)
{
GChildWatchSource *child_watch_source;
GChildWatchFunc child_watch_callback = (GChildWatchFunc) callback;
child_watch_source = (GChildWatchSource *) source;
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, child_watch_source->child_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 the positive pid of a child process. On
* Windows 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 #GMainContext
* and must be added to one with g_source_attach() before it will be
* executed.
*
* Note that child watch sources can only be used in conjunction with
* `g_spawn...` when the %G_SPAWN_DO_NOT_REAP_CHILD flag is used.
*
* Note that on platforms where #GPid must be explicitly closed
* (see g_spawn_close_pid()) @pid must not be closed while the
* source is still active. Typically, you will want to call
* g_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` 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 SIGCHILD
*
* 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` for specific processes other than @pid remains a
* valid thing to do.
*
* Returns: the newly-created child watch source
*
* Since: 2.4
**/
GSource *
g_child_watch_source_new (GPid pid)
{
GSource *source;
GChildWatchSource *child_watch_source;
#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_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 */
G_LOCK (unix_signal_lock);
ref_unix_signal_handler_unlocked (SIGCHLD);
unix_child_watches = g_slist_prepend (unix_child_watches, child_watch_source);
if (waitpid (pid, &child_watch_source->child_status, WNOHANG) > 0)
child_watch_source->child_exited = TRUE;
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 #G_PRIORITY_DEFAULT_IDLE and #G_PRIORITY_HIGH_IDLE.
* @pid: process to watch. On POSIX the positive pid of a child process. On
* Windows 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, or %NULL
*
* Sets a function to be called when the child indicated by @pid
* exits, at the priority @priority.
*
* If you obtain @pid from g_spawn_async() or g_spawn_async_with_pipes()
* you will need to pass #G_SPAWN_DO_NOT_REAP_CHILD as flag to
* the spawn function for the child watching to work.
*
* In many programs, you will want to call g_spawn_check_exit_status()
* in the callback to determine whether or not the child exited
* successfully.
*
* Also, note that on platforms where #GPid must be explicitly closed
* (see g_spawn_close_pid()) @pid must not be closed while the source
* is still active. Typically, you should invoke g_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
* g_child_watch_source_new() apply to this function.
*
* This internally creates a main loop source using
* g_child_watch_source_new() and attaches it to the main loop context
* using g_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 id to watch. On POSIX the positive pid of a child
* process. On Windows 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, #G_PRIORITY_DEFAULT.
*
* If you obtain @pid from g_spawn_async() or g_spawn_async_with_pipes()
* you will need to pass #G_SPAWN_DO_NOT_REAP_CHILD as flag to
* the spawn function for the child watching to work.
*
* Note that on platforms where #GPid must be explicitly closed
* (see g_spawn_close_pid()) @pid must not be closed while the
* source is still active. Typically, you will want to call
* g_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
* g_child_watch_source_new() apply to this function.
*
* This internally creates a main loop source using
* g_child_watch_source_new() and attaches it to the main loop context
* using g_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)
{
gboolean again;
if (!callback)
{
g_warning ("Idle source dispatched without callback. "
"You must call g_source_set_callback().");
return FALSE;
}
again = callback (user_data);
TRACE (GLIB_IDLE_DISPATCH (source, source->context, callback, user_data, again));
return again;
}
/**
* g_idle_source_new:
*
* Creates a new idle source.
*
* The source will not initially be associated with any #GMainContext
* and must be added to one with g_source_attach() before it will be
* executed. Note that the default priority for idle sources is
* %G_PRIORITY_DEFAULT_IDLE, as compared to other sources which
* have a default priority of %G_PRIORITY_DEFAULT.
*
* Returns: the newly-created idle source
**/
GSource *
g_idle_source_new (void)
{
GSource *source;
source = g_source_new (&g_idle_funcs, sizeof (GSource));
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_name (source, "GIdleSource");
return source;
}
/**
* g_idle_add_full: (rename-to g_idle_add)
* @priority: the priority of the idle source. Typically this will be in the
* range between #G_PRIORITY_DEFAULT_IDLE and #G_PRIORITY_HIGH_IDLE.
* @function: function to call
* @data: data to pass to @function
* @notify: (nullable): function to call when the idle is removed, or %NULL
*
* Adds a function to be called whenever there are no higher priority
* events pending. If the function returns %FALSE it is automatically
* removed from the list of event sources and will not be called again.
*
* See [memory management of sources][mainloop-memory-management] for details
* on how to handle the return value and memory management of @data.
*
* This internally creates a main loop source using g_idle_source_new()
* and attaches it to the global #GMainContext using g_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)
{
GSource *source;
guint id;
g_return_val_if_fail (function != NULL, 0);
source = g_idle_source_new ();
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:
* @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, #G_PRIORITY_DEFAULT_IDLE. If the function
* returns %FALSE it is automatically removed from the list of event
* sources and will not be called again.
*
* See [memory management of sources][mainloop-memory-management] for details
* on how to handle the return value and memory management of @data.
*
* This internally creates a main loop source using g_idle_source_new()
* and attaches it to the global #GMainContext using g_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_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.
**/
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 #GMainContext, or %NULL
* @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 g_main_context_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 g_main_context_acquire() succeeds, then
* @function is called and g_main_context_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 #G_PRIORITY_DEFAULT
* priority. If you want a different priority, use
* g_main_context_invoke_full().
*
* Note that, as with normal idle functions, @function should probably
* return %FALSE. If it returns %TRUE, 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 #GMainContext, or %NULL
* @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, or %NULL.
*
* Invokes a function in such a way that @context is owned during the
* invocation of @function.
*
* This function is the same as g_main_context_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 #GDestroyNotify for @data.
*
* @notify 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;
}
Reference in New Issue View Git Blame Copy Permalink