minor optimization.
[platform/upstream/glib.git] / gmain.c
diff --git a/gmain.c b/gmain.c
index 7e3571b..a3b1834 100644 (file)
--- a/gmain.c
+++ b/gmain.c
  * Boston, MA 02111-1307, USA.
  */
 
+/*
+ * Modified by the GLib Team and others 1997-1999.  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"
 
+/* uncomment the next line to get poll() debugging info */
+/* #define G_MAIN_POLL_DEBUG */
+
+
+
 #include "glib.h"
 #include <sys/types.h>
 #include <time.h>
 #ifdef HAVE_SYS_TIME_H
 #include <sys/time.h>
-#endif
-#ifdef GLIB_HAVE_SYS_POLL_H
+#endif /* HAVE_SYS_TIME_H */
+#ifdef GLIB_HAVE_SYS_POLL_H
 #  include <sys/poll.h>
 #  undef events         /* AIX 4.1.5 & 4.3.2 define this for SVR3,4 compatibility */
 #  undef revents /* AIX 4.1.5 & 4.3.2 define this for SVR3,4 compatibility */
-#endif /* GLIB_HAVE_SYS_POLL_H */
+#endif /* GLIB_HAVE_SYS_POLL_H */
 #ifdef HAVE_UNISTD_H
 #include <unistd.h>
-#endif
+#endif /* HAVE_UNISTD_H */
 #include <errno.h>
 
-#ifdef NATIVE_WIN32
+#ifdef G_OS_WIN32
 #define STRICT
 #include <windows.h>
-#endif
+#endif /* G_OS_WIN32 */
 
-#ifdef _MSC_VER
-#include <fcntl.h>
-#include <io.h>
-#endif
+#ifdef G_OS_BEOS
+#include <net/socket.h>
+#endif /* G_OS_BEOS */
 
 /* Types */
 
-typedef struct _GIdleData GIdleData;
 typedef struct _GTimeoutData GTimeoutData;
 typedef struct _GSource GSource;
 typedef struct _GPollRec GPollRec;
@@ -77,11 +87,6 @@ struct _GMainLoop
   gboolean is_running;
 };
 
-struct _GIdleData
-{
-  GSourceFunc callback;
-};
-
 struct _GTimeoutData
 {
   GTimeVal    expiration;
@@ -100,53 +105,61 @@ struct _GPollRec
 
 static gint     g_source_compare          (GHook      *a,
                                           GHook      *b);
-static void     g_source_free_func        (GHookList  *hook_list,
+static void     g_source_destroy_func     (GHookList  *hook_list,
                                           GHook      *hook);
 static void     g_main_poll               (gint      timeout,
                                           gboolean  use_priority, 
                                           gint      priority);
 static void     g_main_add_poll_unlocked  (gint      priority,
                                           GPollFD  *fd);
+static void     g_main_wakeup             (void);
 
 static gboolean g_timeout_prepare      (gpointer  source_data, 
                                        GTimeVal *current_time,
-                                       gint     *timeout);
+                                       gint     *timeout,
+                                       gpointer  user_data);
 static gboolean g_timeout_check        (gpointer  source_data,
-                                       GTimeVal *current_time);
-static gboolean g_timeout_dispatch     (gpointer  source_data,
                                        GTimeVal *current_time,
                                        gpointer  user_data);
+static gboolean g_timeout_dispatch     (gpointer  source_data,
+                                       GTimeVal *dispatch_time,
+                                       gpointer  user_data);
 static gboolean g_idle_prepare         (gpointer  source_data, 
                                        GTimeVal *current_time,
-                                       gint     *timeout);
+                                       gint     *timeout,
+                                       gpointer  user_data);
 static gboolean g_idle_check           (gpointer  source_data,
-                                       GTimeVal *current_time);
-static gboolean g_idle_dispatch        (gpointer  source_data,
                                        GTimeVal *current_time,
                                        gpointer  user_data);
+static gboolean g_idle_dispatch        (gpointer  source_data,
+                                       GTimeVal *dispatch_time,
+                                       gpointer  user_data);
 
 /* Data */
 
 static GSList *pending_dispatches = NULL;
 static GHookList source_list = { 0 };
+static gint in_check_or_prepare = 0;
 
 /* The following lock is used for both the list of sources
  * and the list of poll records
  */
-G_LOCK_DECLARE_STATIC (main_loop);
+G_LOCK_DEFINE_STATIC (main_loop);
 
-static GSourceFuncs timeout_funcs = {
+static GSourceFuncs timeout_funcs =
+{
   g_timeout_prepare,
   g_timeout_check,
   g_timeout_dispatch,
-  (GDestroyNotify)g_free
+  g_free,
 };
 
-static GSourceFuncs idle_funcs = {
+static GSourceFuncs idle_funcs =
+{
   g_idle_prepare,
   g_idle_check,
   g_idle_dispatch,
-  (GDestroyNotify)g_free
+  NULL,
 };
 
 static GPollRec *poll_records = NULL;
@@ -155,21 +168,28 @@ static GMemChunk *poll_chunk;
 static guint n_poll_records = 0;
 
 #ifdef G_THREADS_ENABLED
-#ifndef NATIVE_WIN32
+#ifndef G_OS_WIN32
 /* this pipe is used to wake up the main loop when a source is added.
  */
 static gint wake_up_pipe[2] = { -1, -1 };
-#else
+#else /* G_OS_WIN32 */
 static HANDLE wake_up_semaphore = NULL;
-#endif
+#endif /* G_OS_WIN32 */
 static GPollFD wake_up_rec;
 static gboolean poll_waiting = FALSE;
-#endif
+
+/* Flag indicating whether the set of fd's changed during a poll */
+static gboolean poll_changed = FALSE;
+#endif /* G_THREADS_ENABLED */
 
 #ifdef HAVE_POLL
+/* SunOS has poll, but doesn't provide a prototype. */
+#  if defined (sun) && !defined (__SVR4)
+extern gint poll (GPollFD *ufds, guint nfsd, gint timeout);
+#  endif  /* !sun */
 static GPollFunc poll_func = (GPollFunc) poll;
 #else  /* !HAVE_POLL */
-#ifdef NATIVE_WIN32
+#ifdef G_OS_WIN32
 
 static gint
 g_poll (GPollFD *fds, guint nfds, gint timeout)
@@ -307,7 +327,7 @@ g_poll (GPollFD *fds, guint nfds, gint timeout)
     return 1;
 }
 
-#else  /* !NATIVE_WIN32 */
+#else  /* !G_OS_WIN32 */
 
 /* The following implementation of poll() comes from the GNU C Library.
  * Copyright (C) 1994, 1996, 1997 Free Software Foundation, Inc.
@@ -317,23 +337,29 @@ g_poll (GPollFD *fds, guint nfds, gint timeout)
 
 #ifdef HAVE_SYS_SELECT_H
 #include <sys/select.h>
-#endif /* HAVE_SYS_SELECT_H_ */
+#endif /* HAVE_SYS_SELECT_H */
+
+#ifdef G_OS_BEOS
+#undef NO_FD_SET
+#endif /* G_OS_BEOS */
 
 #ifndef NO_FD_SET
 #  define SELECT_MASK fd_set
-#else  /* !NO_FD_SET */
+#else /* !NO_FD_SET */
 #  ifndef _AIX
 typedef long fd_mask;
-#  endif
-#  if defined(_IBMR2)
+#  endif /* _AIX */
+#  ifdef _IBMR2
 #    define SELECT_MASK void
-#  else
+#  else /* !_IBMR2 */
 #    define SELECT_MASK int
-#  endif
-#endif /* !NO_FD_SET */
+#  endif /* !_IBMR2 */
+#endif /* !NO_FD_SET */
 
 static gint 
-g_poll (GPollFD *fds, guint nfds, gint timeout)
+g_poll (GPollFD *fds,
+       guint    nfds,
+       gint     timeout)
 {
   struct timeval tv;
   SELECT_MASK rset, wset, xset;
@@ -380,7 +406,8 @@ g_poll (GPollFD *fds, guint nfds, gint timeout)
 
   return ready;
 }
-#endif /* !NATIVE_WIN32 */
+
+#endif /* !G_OS_WIN32 */
 
 static GPollFunc poll_func = g_poll;
 #endif /* !HAVE_POLL */
@@ -400,13 +427,25 @@ g_source_compare (GHook *a,
   return (source_a->priority < source_b->priority) ? -1 : 1;
 }
 
+/* HOLDS: main_loop lock */
 static void
-g_source_free_func (GHookList      *hook_list,
-                   GHook          *hook)
+g_source_destroy_func (GHookList *hook_list,
+                      GHook     *hook)
 {
-  GSource *source = (GSource *)hook;
+  GSource *source = (GSource*) hook;
+  GDestroyNotify destroy;
+
+  G_UNLOCK (main_loop);
 
-  ((GSourceFuncs *) hook->func)->destroy (source->source_data);
+  destroy = hook->destroy;
+  if (destroy)
+    destroy (hook->data);
+
+  destroy = ((GSourceFuncs*) hook->func)->destroy;
+  if (destroy)
+    destroy (source->source_data);
+
+  G_LOCK (main_loop);
 }
 
 guint 
@@ -423,11 +462,14 @@ g_source_add (gint           priority,
   G_LOCK (main_loop);
 
   if (!source_list.is_setup)
-    g_hook_list_init (&source_list, sizeof(GSource));
+    {
+      g_hook_list_init (&source_list, sizeof (GSource));
 
-  source_list.hook_free = g_source_free_func;
+      source_list.hook_destroy = G_HOOK_DEFERRED_DESTROY;
+      source_list.hook_free = g_source_destroy_func;
+    }
 
-  source = (GSource *)g_hook_alloc (&source_list);
+  source = (GSource*) g_hook_alloc (&source_list);
   source->priority = priority;
   source->source_data = source_data;
   source->hook.func = funcs;
@@ -445,27 +487,21 @@ g_source_add (gint           priority,
 
 #ifdef G_THREADS_ENABLED
   /* Now wake up the main loop if it is waiting in the poll() */
-
-  if (poll_waiting)
-    {
-      poll_waiting = FALSE;
-#ifndef NATIVE_WIN32
-      write (wake_up_pipe[1], "A", 1);
-#else
-      ReleaseSemaphore (wake_up_semaphore, 1, NULL);
-#endif
-    }
+  g_main_wakeup ();
 #endif
+  
   G_UNLOCK (main_loop);
 
   return return_val;
 }
 
-void 
+gboolean
 g_source_remove (guint tag)
 {
   GHook *hook;
 
+  g_return_val_if_fail (tag > 0, FALSE);
+
   G_LOCK (main_loop);
 
   hook = g_hook_get (&source_list, tag);
@@ -473,9 +509,11 @@ g_source_remove (guint tag)
     g_hook_destroy_link (&source_list, hook);
 
   G_UNLOCK (main_loop);
+
+  return hook != NULL;
 }
 
-void 
+gboolean
 g_source_remove_by_user_data (gpointer user_data)
 {
   GHook *hook;
@@ -487,6 +525,8 @@ g_source_remove_by_user_data (gpointer user_data)
     g_hook_destroy_link (&source_list, hook);
 
   G_UNLOCK (main_loop);
+
+  return hook != NULL;
 }
 
 static gboolean
@@ -498,7 +538,7 @@ g_source_find_source_data (GHook    *hook,
   return (source->source_data == data);
 }
 
-void 
+gboolean
 g_source_remove_by_source_data (gpointer source_data)
 {
   GHook *hook;
@@ -511,12 +551,47 @@ g_source_remove_by_source_data (gpointer source_data)
     g_hook_destroy_link (&source_list, hook);
 
   G_UNLOCK (main_loop);
+
+  return hook != NULL;
+}
+
+static gboolean
+g_source_find_funcs_user_data (GHook   *hook,
+                              gpointer data)
+{
+  gpointer *d = data;
+
+  return hook->func == d[0] && hook->data == d[1];
+}
+
+gboolean
+g_source_remove_by_funcs_user_data (GSourceFuncs *funcs,
+                                   gpointer      user_data)
+{
+  gpointer d[2];
+  GHook *hook;
+
+  g_return_val_if_fail (funcs != NULL, FALSE);
+
+  G_LOCK (main_loop);
+
+  d[0] = funcs;
+  d[1] = user_data;
+
+  hook = g_hook_find (&source_list, TRUE,
+                     g_source_find_funcs_user_data, d);
+  if (hook)
+    g_hook_destroy_link (&source_list, hook);
+
+  G_UNLOCK (main_loop);
+
+  return hook != NULL;
 }
 
 void
 g_get_current_time (GTimeVal *result)
 {
-#ifndef _MSC_VER
+#ifndef G_OS_WIN32
   struct timeval r;
   g_return_if_fail (result != NULL);
 
@@ -554,7 +629,7 @@ g_get_current_time (GTimeVal *result)
 
 /* HOLDS: main_loop_lock */
 static void
-g_main_dispatch (GTimeVal *current_time)
+g_main_dispatch (GTimeVal *dispatch_time)
 {
   while (pending_dispatches != NULL)
     {
@@ -582,7 +657,7 @@ g_main_dispatch (GTimeVal *current_time)
 
          G_UNLOCK (main_loop);
          need_destroy = ! dispatch (source_data,
-                                    current_time,
+                                    dispatch_time,
                                     hook_data);
          G_LOCK (main_loop);
 
@@ -632,7 +707,7 @@ g_main_iterate (gboolean block,
                gboolean dispatch)
 {
   GHook *hook;
-  GTimeVal current_time  ={ 0, 0 };
+  GTimeVal current_time  = { 0, 0 };
   gint n_ready = 0;
   gint current_priority = 0;
   gint timeout;
@@ -643,6 +718,15 @@ g_main_iterate (gboolean block,
   g_get_current_time (&current_time);
 
   G_LOCK (main_loop);
+
+#ifdef G_THREADS_ENABLED
+  if (poll_waiting)
+    {
+      g_warning("g_main_iterate(): main loop already active in another thread");
+      G_UNLOCK (main_loop);
+      return FALSE;
+    }
+#endif G_THREADS_ENABLED  
   
   /* If recursing, finish up current dispatch, before starting over */
   if (pending_dispatches)
@@ -662,7 +746,7 @@ g_main_iterate (gboolean block,
   hook = g_hook_first_valid (&source_list, TRUE);
   while (hook)
     {
-      GSource *source = (GSource *)hook;
+      GSource *source = (GSource*) hook;
       gint source_timeout = -1;
 
       if ((n_ready > 0) && (source->priority > current_priority))
@@ -676,14 +760,28 @@ g_main_iterate (gboolean block,
          continue;
        }
 
-      if (hook->flags & G_SOURCE_READY ||
-         ((GSourceFuncs *) hook->func)->prepare (source->source_data,
-                                                 &current_time,
-                                                 &source_timeout))
+      if (!(hook->flags & G_SOURCE_READY))
+       {
+         gboolean (*prepare)  (gpointer  source_data, 
+                               GTimeVal *current_time,
+                               gint     *timeout,
+                               gpointer  user_data);
+
+         prepare = ((GSourceFuncs *) hook->func)->prepare;
+         in_check_or_prepare++;
+         G_UNLOCK (main_loop);
+
+         if ((*prepare) (source->source_data, &current_time, &source_timeout, source->hook.data))
+           hook->flags |= G_SOURCE_READY;
+         
+         G_LOCK (main_loop);
+         in_check_or_prepare--;
+       }
+
+      if (hook->flags & G_SOURCE_READY)
        {
          if (!dispatch)
            {
-             hook->flags |= G_SOURCE_READY;
              g_hook_unref (&source_list, hook);
              G_UNLOCK (main_loop);
 
@@ -691,7 +789,6 @@ g_main_iterate (gboolean block,
            }
          else
            {
-             hook->flags |= G_SOURCE_READY;
              n_ready++;
              current_priority = source->priority;
              timeout = 0;
@@ -713,6 +810,9 @@ g_main_iterate (gboolean block,
 
   g_main_poll (timeout, n_ready > 0, current_priority);
 
+  if (timeout != 0)
+    g_get_current_time (&current_time);
+  
   /* Check to see what sources need to be dispatched */
 
   n_ready = 0;
@@ -733,9 +833,24 @@ g_main_iterate (gboolean block,
          continue;
        }
 
-      if (hook->flags & G_SOURCE_READY ||
-         ((GSourceFuncs *) hook->func)->check (source->source_data,
-                                               &current_time))
+      if (!(hook->flags & G_SOURCE_READY))
+       {
+         gboolean (*check) (gpointer  source_data,
+                            GTimeVal *current_time,
+                            gpointer  user_data);
+
+         check = ((GSourceFuncs *) hook->func)->check;
+         in_check_or_prepare++;
+         G_UNLOCK (main_loop);
+         
+         if ((*check) (source->source_data, &current_time, source->hook.data))
+           hook->flags |= G_SOURCE_READY;
+
+         G_LOCK (main_loop);
+         in_check_or_prepare--;
+       }
+
+      if (hook->flags & G_SOURCE_READY)
        {
          if (dispatch)
            {
@@ -756,7 +871,7 @@ g_main_iterate (gboolean block,
       
       hook = g_hook_next_valid (&source_list, hook, TRUE);
     }
-
   /* Now invoke the callbacks */
 
   if (pending_dispatches)
@@ -774,9 +889,9 @@ g_main_iterate (gboolean block,
 /* See if any events are pending
  */
 gboolean 
-g_main_pending ()
+g_main_pending (void)
 {
-  return g_main_iterate (FALSE, FALSE);
+  return in_check_or_prepare ? FALSE : g_main_iterate (FALSE, FALSE);
 }
 
 /* Run a single iteration of the mainloop. If block is FALSE,
@@ -785,7 +900,14 @@ g_main_pending ()
 gboolean
 g_main_iteration (gboolean block)
 {
-  return g_main_iterate (block, TRUE);
+  if (in_check_or_prepare)
+    {
+      g_warning ("g_main_iteration(): called recursively from within a source's check() or "
+                "prepare() member or from a second thread, iteration not possible");
+      return FALSE;
+    }
+  else
+    return g_main_iterate (block, TRUE);
 }
 
 GMainLoop*
@@ -804,6 +926,13 @@ g_main_run (GMainLoop *loop)
 {
   g_return_if_fail (loop != NULL);
 
+  if (in_check_or_prepare)
+    {
+      g_warning ("g_main_run(): called recursively from within a source's check() or "
+                "prepare() member or from a second thread, iteration not possible");
+      return;
+    }
+  
   loop->is_running = TRUE;
   while (loop->is_running)
     g_main_iterate (TRUE, TRUE);
@@ -839,13 +968,16 @@ g_main_poll (gint     timeout,
             gboolean use_priority,
             gint     priority)
 {
+#ifdef  G_MAIN_POLL_DEBUG
+  GTimer *poll_timer;
+#endif
   GPollFD *fd_array;
   GPollRec *pollrec;
-
   gint i;
   gint npoll;
+
 #ifdef G_THREADS_ENABLED
-#ifndef NATIVE_WIN32
+#ifndef G_OS_WIN32
   if (wake_up_pipe[0] < 0)
     {
       if (pipe (wake_up_pipe) < 0)
@@ -873,40 +1005,106 @@ g_main_poll (gint     timeout,
   i = 0;
   while (pollrec && (!use_priority || priority >= pollrec->priority))
     {
-      fd_array[i].fd = pollrec->fd->fd;
-      fd_array[i].events = pollrec->fd->events;
-      fd_array[i].revents = 0;
-       
+      if (pollrec->fd->events)
+       {
+         fd_array[i].fd = pollrec->fd->fd;
+         /* 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.
+          */
+         fd_array[i].events = pollrec->fd->events & ~(G_IO_ERR|G_IO_HUP|G_IO_NVAL);
+         fd_array[i].revents = 0;
+         i++;
+       }
+      
       pollrec = pollrec->next;
-      i++;
     }
 #ifdef G_THREADS_ENABLED
   poll_waiting = TRUE;
+  poll_changed = FALSE;
 #endif
-  G_UNLOCK (main_loop);
+  
   npoll = i;
-  (*poll_func) (fd_array, npoll, timeout);
-  G_LOCK (main_loop);
-
+  if (npoll || timeout != 0)
+    {
+#ifdef G_MAIN_POLL_DEBUG
+      g_print ("g_main_poll(%d) timeout: %d\r", npoll, timeout);
+      poll_timer = g_timer_new ();
+#endif
+      
+      G_UNLOCK (main_loop);
+      (*poll_func) (fd_array, npoll, timeout);
+      G_LOCK (main_loop);
+      
+#ifdef G_MAIN_POLL_DEBUG
+      g_print ("g_main_poll(%d) timeout: %d - elapsed %12.10f seconds",
+              npoll,
+              timeout,
+              g_timer_elapsed (poll_timer, NULL));
+      g_timer_destroy (poll_timer);
+      pollrec = poll_records;
+      i = 0;
+      while (i < npoll)
+       {
+         if (pollrec->fd->events)
+           {
+             if (fd_array[i].revents)
+               {
+                 g_print (" [%d:", fd_array[i].fd);
+                 if (fd_array[i].revents & G_IO_IN)
+                   g_print ("i");
+                 if (fd_array[i].revents & G_IO_OUT)
+                   g_print ("o");
+                 if (fd_array[i].revents & G_IO_PRI)
+                   g_print ("p");
+                 if (fd_array[i].revents & G_IO_ERR)
+                   g_print ("e");
+                 if (fd_array[i].revents & G_IO_HUP)
+                   g_print ("h");
+                 if (fd_array[i].revents & G_IO_NVAL)
+                   g_print ("n");
+                 g_print ("]");
+               }
+             i++;
+           }
+         pollrec = pollrec->next;
+       }
+      g_print ("\n");
+#endif
+    } /* if (npoll || timeout != 0) */
+  
 #ifdef G_THREADS_ENABLED
   if (!poll_waiting)
     {
-#ifndef NATIVE_WIN32
+#ifndef G_OS_WIN32
       gchar c;
       read (wake_up_pipe[0], &c, 1);
 #endif
     }
   else
     poll_waiting = FALSE;
+
+  /* If the set of poll file descriptors changed, bail out
+   * and let the main loop rerun
+   */
+  if (poll_changed)
+    {
+      g_free (fd_array);
+      return;
+    }
 #endif
 
   pollrec = poll_records;
   i = 0;
   while (i < npoll)
     {
-      pollrec->fd->revents = fd_array[i].revents;
+      if (pollrec->fd->events)
+       {
+         pollrec->fd->revents = fd_array[i].revents;
+         i++;
+       }
       pollrec = pollrec->next;
-      i++;
     }
 
   g_free (fd_array);
@@ -958,6 +1156,13 @@ g_main_add_poll_unlocked (gint     priority,
   newrec->next = pollrec;
 
   n_poll_records++;
+
+#ifdef G_THREADS_ENABLED
+  poll_changed = TRUE;
+
+  /* Now wake up the main loop if it is waiting in the poll() */
+  g_main_wakeup ();
+#endif
 }
 
 void 
@@ -989,6 +1194,13 @@ g_main_remove_poll (GPollFD *fd)
       pollrec = pollrec->next;
     }
 
+#ifdef G_THREADS_ENABLED
+  poll_changed = TRUE;
+  
+  /* Now wake up the main loop if it is waiting in the poll() */
+  g_main_wakeup ();
+#endif
+
   G_UNLOCK (main_loop);
 }
 
@@ -999,91 +1211,120 @@ g_main_set_poll_func (GPollFunc func)
     poll_func = func;
   else
 #ifdef HAVE_POLL
-    poll_func = (GPollFunc)poll;
+    poll_func = (GPollFunc) poll;
+#else
+    poll_func = (GPollFunc) g_poll;
+#endif
+}
+
+/* Wake the main loop up from a poll() */
+static void
+g_main_wakeup (void)
+{
+#ifdef G_THREADS_ENABLED
+  if (poll_waiting)
+    {
+      poll_waiting = FALSE;
+#ifndef G_OS_WIN32
+      write (wake_up_pipe[1], "A", 1);
 #else
-    poll_func = (GPollFunc)g_poll;
+      ReleaseSemaphore (wake_up_semaphore, 1, NULL);
+#endif
+    }
 #endif
 }
 
 /* Timeouts */
 
-static gboolean 
-g_timeout_prepare  (gpointer source_data, 
+static void
+g_timeout_set_expiration (GTimeoutData *data,
+                         GTimeVal     *current_time)
+{
+  guint seconds = data->interval / 1000;
+  guint msecs = data->interval - seconds * 1000;
+
+  data->expiration.tv_sec = current_time->tv_sec + seconds;
+  data->expiration.tv_usec = current_time->tv_usec + msecs * 1000;
+  if (data->expiration.tv_usec >= 1000000)
+    {
+      data->expiration.tv_usec -= 1000000;
+      data->expiration.tv_sec++;
+    }
+}
+
+static gboolean
+g_timeout_prepare  (gpointer  source_data,
                    GTimeVal *current_time,
-                   gint    *timeout)
+                   gint     *timeout,
+                   gpointer  user_data)
 {
   glong msec;
   GTimeoutData *data = source_data;
-
-  msec = (data->expiration.tv_sec  - current_time->tv_sec) * 1000 +
-         (data->expiration.tv_usec - current_time->tv_usec) / 1000;
-
-  *timeout = (msec <= 0) ? 0 : msec;
-
-  return (msec <= 0);
+  
+  msec = ((data->expiration.tv_sec  - current_time->tv_sec) * 1000 +
+         (data->expiration.tv_usec - current_time->tv_usec) / 1000);
+  
+  if (msec < 0)
+    msec = 0;
+  else if (msec > data->interval)
+    {
+      /* The system time has been set backwards, so we
+       * reset the expiration time to now + data->interval;
+       * this at least avoids hanging for long periods of time.
+       */
+      g_timeout_set_expiration (data, current_time);
+      msec = data->interval;
+    }
+  
+  *timeout = msec;
+  
+  return msec == 0;
 }
 
 static gboolean 
-g_timeout_check    (gpointer source_data,
-                   GTimeVal *current_time)
+g_timeout_check (gpointer  source_data,
+                GTimeVal *current_time,
+                gpointer  user_data)
 {
   GTimeoutData *data = source_data;
-
-  return (data->expiration.tv_sec < current_time->tv_sec) ||
-         ((data->expiration.tv_sec == current_time->tv_sec) &&
-         (data->expiration.tv_usec <= current_time->tv_usec));
+  
+  return ((data->expiration.tv_sec < current_time->tv_sec) ||
+         ((data->expiration.tv_sec == current_time->tv_sec) &&
+          (data->expiration.tv_usec <= current_time->tv_usec)));
 }
 
 static gboolean
-g_timeout_dispatch (gpointer source_data, 
-                   GTimeVal *current_time,
+g_timeout_dispatch (gpointer source_data,
+                   GTimeVal *dispatch_time,
                    gpointer user_data)
 {
   GTimeoutData *data = source_data;
 
-  if (data->callback(user_data))
+  if (data->callback (user_data))
     {
-      guint seconds = data->interval / 1000;
-      guint msecs = data->interval - seconds * 1000;
+      g_timeout_set_expiration (data, dispatch_time);
 
-      data->expiration.tv_sec = current_time->tv_sec + seconds;
-      data->expiration.tv_usec = current_time->tv_usec + msecs * 1000;
-      if (data->expiration.tv_usec >= 1000000)
-       {
-         data->expiration.tv_usec -= 1000000;
-         data->expiration.tv_sec++;
-       }
       return TRUE;
     }
   else
     return FALSE;
 }
 
-guint 
+guint
 g_timeout_add_full (gint           priority,
-                   guint          interval, 
+                   guint          interval,
                    GSourceFunc    function,
                    gpointer       data,
                    GDestroyNotify notify)
 {
-  guint seconds;
-  guint msecs;
   GTimeoutData *timeout_data = g_new (GTimeoutData, 1);
+  GTimeVal current_time;
 
   timeout_data->interval = interval;
   timeout_data->callback = function;
-  g_get_current_time (&timeout_data->expiration);
-
-  seconds = timeout_data->interval / 1000;
-  msecs = timeout_data->interval - seconds * 1000;
+  g_get_current_time (&current_time);
 
-  timeout_data->expiration.tv_sec += seconds;
-  timeout_data->expiration.tv_usec += msecs * 1000;
-  if (timeout_data->expiration.tv_usec >= 1000000)
-    {
-      timeout_data->expiration.tv_usec -= 1000000;
-      timeout_data->expiration.tv_sec++;
-    }
+  g_timeout_set_expiration (timeout_data, &current_time);
 
   return g_source_add (priority, FALSE, &timeout_funcs, timeout_data, data, notify);
 }
@@ -1100,9 +1341,10 @@ g_timeout_add (guint32        interval,
 /* Idle functions */
 
 static gboolean 
-g_idle_prepare  (gpointer source_data, 
+g_idle_prepare  (gpointer  source_data, 
                 GTimeVal *current_time,
-                gint     *timeout)
+                gint     *timeout,
+                gpointer  user_data)
 {
   timeout = 0;
   return TRUE;
@@ -1110,32 +1352,31 @@ g_idle_prepare  (gpointer source_data,
 
 static gboolean 
 g_idle_check    (gpointer  source_data,
-                GTimeVal *current_time)
+                GTimeVal *current_time,
+                gpointer  user_data)
 {
   return TRUE;
 }
 
 static gboolean
 g_idle_dispatch (gpointer source_data, 
-                GTimeVal *current_time,
+                GTimeVal *dispatch_time,
                 gpointer user_data)
 {
-  GIdleData *data = source_data;
+  GSourceFunc func = source_data;
 
-  return (*data->callback)(user_data);
+  return func (user_data);
 }
 
 guint 
-g_idle_add_full (gint          priority,
+g_idle_add_full (gint           priority,
                 GSourceFunc    function,
                 gpointer       data,
                 GDestroyNotify notify)
 {
-  GIdleData *idle_data = g_new (GIdleData, 1);
-
-  idle_data->callback = function;
+  g_return_val_if_fail (function != NULL, 0);
 
-  return g_source_add (priority, FALSE, &idle_funcs, idle_data, data, notify);
+  return g_source_add (priority, FALSE, &idle_funcs, function, data, notify);
 }
 
 guint 
@@ -1144,3 +1385,9 @@ g_idle_add (GSourceFunc    function,
 {
   return g_idle_add_full (G_PRIORITY_DEFAULT_IDLE, function, data, NULL);
 }
+
+gboolean
+g_idle_remove_by_data (gpointer data)
+{
+  return g_source_remove_by_funcs_user_data (&idle_funcs, data);
+}