gobject/gobjectnotifyqueue.c

   1 /* GObject - GLib Type, Object, Parameter and Signal Library
   2  * Copyright (C) 1998-1999, 2000-2001 Tim Janik and Red Hat, Inc.
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General
  15  * Public License along with this library; if not, write to the
  16  * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  17  * Boston, MA 02111-1307, USA.
  18  */
  19
  20 /* WARNING:
  21  *
  22  *    This file is INSTALLED and other projects (outside of glib)
  23  *    #include its contents.
  24  */
  25
  26 #ifndef __G_OBJECT_NOTIFY_QUEUE_H__
  27 #define __G_OBJECT_NOTIFY_QUEUE_H__
  28
  29 #include <string.h> /* memset */
  30
  31 #include <glib-object.h>
  32
  33 G_BEGIN_DECLS
  34
  35
  36 /* --- typedefs --- */
  37 typedef struct _GObjectNotifyContext          GObjectNotifyContext;
  38 typedef struct _GObjectNotifyQueue            GObjectNotifyQueue;
  39 typedef void (*GObjectNotifyQueueDispatcher) (GObject     *object,
  40                                               guint        n_pspecs,
  41                                               GParamSpec **pspecs);
  42
  43
  44 /* --- structures --- */
  45 struct _GObjectNotifyContext
  46 {
  47   GQuark                       quark_notify_queue;
  48   GObjectNotifyQueueDispatcher dispatcher;
  49   GTrashStack                 *_nqueue_trash; /* unused */
  50 };
  51 struct _GObjectNotifyQueue
  52 {
  53   GObjectNotifyContext *context;
  54   GSList               *pspecs;
  55   guint16               n_pspecs;
  56   guint16               freeze_count;
  57 };
  58
  59 G_LOCK_DEFINE_STATIC(notify_lock);
  60
  61 /* --- functions --- */
  62 static void
  63 g_object_notify_queue_free (gpointer data)
  64 {
  65   GObjectNotifyQueue *nqueue = data;
  66
  67   g_slist_free (nqueue->pspecs);
  68   g_slice_free (GObjectNotifyQueue, nqueue);
  69 }
  70
  71 static inline GObjectNotifyQueue*
  72 g_object_notify_queue_freeze (GObject              *object,
  73                               GObjectNotifyContext *context)
  74 {
  75   GObjectNotifyQueue *nqueue;
  76
  77   G_LOCK(notify_lock);
  78   nqueue = g_datalist_id_get_data (&object->qdata, context->quark_notify_queue);
  79   if (!nqueue)
  80     {
  81       nqueue = g_slice_new0 (GObjectNotifyQueue);
  82       nqueue->context = context;
  83       g_datalist_id_set_data_full (&object->qdata, context->quark_notify_queue,
  84                                    nqueue, g_object_notify_queue_free);
  85     }
  86
  87   if (nqueue->freeze_count >= 65535)
  88     g_critical("Free queue for %s (%p) is larger than 65535,"
  89                " called g_object_freeze_notify() too often."
  90                " Forgot to call g_object_thaw_notify() or infinite loop",
  91                G_OBJECT_TYPE_NAME (object), object);
  92   else
  93     nqueue->freeze_count++;
  94   G_UNLOCK(notify_lock);
  95
  96   return nqueue;
  97 }
  98
  99 static inline void
 100 g_object_notify_queue_thaw (GObject            *object,
 101                             GObjectNotifyQueue *nqueue)
 102 {
 103   GObjectNotifyContext *context = nqueue->context;
 104   GParamSpec *pspecs_mem[16], **pspecs, **free_me = NULL;
 105   GSList *slist;
 106   guint n_pspecs = 0;
 107
 108   g_return_if_fail (nqueue->freeze_count > 0);
 109   g_return_if_fail (g_atomic_int_get(&object->ref_count) > 0);
 110
 111   G_LOCK(notify_lock);
 112
 113   /* Just make sure we never get into some nasty race condition */
 114   if (G_UNLIKELY(nqueue->freeze_count == 0)) {
 115     G_UNLOCK(notify_lock);
 116     g_warning ("%s: property-changed notification for %s(%p) is not frozen",
 117                G_STRFUNC, G_OBJECT_TYPE_NAME (object), object);
 118     return;
 119   }
 120
 121   nqueue->freeze_count--;
 122   if (nqueue->freeze_count) {
 123     G_UNLOCK(notify_lock);
 124     return;
 125   }
 126
 127   pspecs = nqueue->n_pspecs > 16 ? free_me = g_new (GParamSpec*, nqueue->n_pspecs) : pspecs_mem;
 128
 129   for (slist = nqueue->pspecs; slist; slist = slist->next)
 130     {
 131       pspecs[n_pspecs++] = slist->data;
 132     }
 133   g_datalist_id_set_data (&object->qdata, context->quark_notify_queue, NULL);
 134
 135   G_UNLOCK(notify_lock);
 136
 137   if (n_pspecs)
 138     context->dispatcher (object, n_pspecs, pspecs);
 139   g_free (free_me);
 140 }
 141
 142 static inline void
 143 g_object_notify_queue_clear (GObject            *object,
 144                              GObjectNotifyQueue *nqueue)
 145 {
 146   g_return_if_fail (nqueue->freeze_count > 0);
 147
 148   G_LOCK(notify_lock);
 149
 150   g_slist_free (nqueue->pspecs);
 151   nqueue->pspecs = NULL;
 152   nqueue->n_pspecs = 0;
 153
 154   G_UNLOCK(notify_lock);
 155 }
 156
 157 static inline void
 158 g_object_notify_queue_add (GObject            *object,
 159                            GObjectNotifyQueue *nqueue,
 160                            GParamSpec         *pspec)
 161 {
 162   if (pspec->flags & G_PARAM_READABLE)
 163     {
 164       GParamSpec *redirect;
 165
 166       G_LOCK(notify_lock);
 167
 168       g_return_if_fail (nqueue->n_pspecs < 65535);
 169
 170       redirect = g_param_spec_get_redirect_target (pspec);
 171       if (redirect)
 172         pspec = redirect;
 173
 174       /* we do the deduping in _thaw */
 175       if (g_slist_find (nqueue->pspecs, pspec) == NULL)
 176         {
 177           nqueue->pspecs = g_slist_prepend (nqueue->pspecs, pspec);
 178           nqueue->n_pspecs++;
 179         }
 180
 181       G_UNLOCK(notify_lock);
 182     }
 183 }
 184
 185 /* NB: This function is not threadsafe, do not ever use it if
 186  * you need a threadsafe notify queue.
 187  * Use g_object_notify_queue_freeze() to acquire the queue and
 188  * g_object_notify_queue_thaw() after you are done instead.
 189  */
 190 static inline GObjectNotifyQueue*
 191 g_object_notify_queue_from_object (GObject              *object,
 192                                    GObjectNotifyContext *context)
 193 {
 194   return g_datalist_id_get_data (&object->qdata, context->quark_notify_queue);
 195 }
 196
 197 G_END_DECLS
 198
 199 #endif /* __G_OBJECT_NOTIFY_QUEUE_H__ */