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 2.1 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, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 /* WARNING:
  19  *
  20  *    This file is INSTALLED and other projects (outside of glib)
  21  *    #include its contents.
  22  */
  23
  24 #ifndef __G_OBJECT_NOTIFY_QUEUE_H__
  25 #define __G_OBJECT_NOTIFY_QUEUE_H__
  26
  27 #include <string.h> /* memset */
  28
  29 #include <glib-object.h>
  30
  31 G_BEGIN_DECLS
  32
  33
  34 /* --- typedefs --- */
  35 typedef struct _GObjectNotifyContext          GObjectNotifyContext;
  36 typedef struct _GObjectNotifyQueue            GObjectNotifyQueue;
  37 typedef void (*GObjectNotifyQueueDispatcher) (GObject     *object,
  38                                               guint        n_pspecs,
  39                                               GParamSpec **pspecs);
  40
  41
  42 /* --- structures --- */
  43 struct _GObjectNotifyContext
  44 {
  45   GQuark                       quark_notify_queue;
  46   GObjectNotifyQueueDispatcher dispatcher;
  47   GTrashStack                 *_nqueue_trash; /* unused */
  48 };
  49 struct _GObjectNotifyQueue
  50 {
  51   GObjectNotifyContext *context;
  52   GSList               *pspecs;
  53   guint16               n_pspecs;
  54   guint16               freeze_count;
  55 };
  56
  57 G_LOCK_DEFINE_STATIC(notify_lock);
  58
  59 /* --- functions --- */
  60 static void
  61 g_object_notify_queue_free (gpointer data)
  62 {
  63   GObjectNotifyQueue *nqueue = data;
  64
  65   g_slist_free (nqueue->pspecs);
  66   g_slice_free (GObjectNotifyQueue, nqueue);
  67 }
  68
  69 static inline GObjectNotifyQueue*
  70 g_object_notify_queue_freeze (GObject              *object,
  71                               GObjectNotifyContext *context)
  72 {
  73   GObjectNotifyQueue *nqueue;
  74
  75   G_LOCK(notify_lock);
  76   nqueue = g_datalist_id_get_data (&object->qdata, context->quark_notify_queue);
  77   if (!nqueue)
  78     {
  79       nqueue = g_slice_new0 (GObjectNotifyQueue);
  80       nqueue->context = context;
  81       g_datalist_id_set_data_full (&object->qdata, context->quark_notify_queue,
  82                                    nqueue, g_object_notify_queue_free);
  83     }
  84
  85   if (nqueue->freeze_count >= 65535)
  86     g_critical("Free queue for %s (%p) is larger than 65535,"
  87                " called g_object_freeze_notify() too often."
  88                " Forgot to call g_object_thaw_notify() or infinite loop",
  89                G_OBJECT_TYPE_NAME (object), object);
  90   else
  91     nqueue->freeze_count++;
  92   G_UNLOCK(notify_lock);
  93
  94   return nqueue;
  95 }
  96
  97 static inline void
  98 g_object_notify_queue_thaw (GObject            *object,
  99                             GObjectNotifyQueue *nqueue)
 100 {
 101   GObjectNotifyContext *context = nqueue->context;
 102   GParamSpec *pspecs_mem[16], **pspecs, **free_me = NULL;
 103   GSList *slist;
 104   guint n_pspecs = 0;
 105
 106   g_return_if_fail (nqueue->freeze_count > 0);
 107   g_return_if_fail (g_atomic_int_get(&object->ref_count) > 0);
 108
 109   G_LOCK(notify_lock);
 110
 111   /* Just make sure we never get into some nasty race condition */
 112   if (G_UNLIKELY(nqueue->freeze_count == 0)) {
 113     G_UNLOCK(notify_lock);
 114     g_warning ("%s: property-changed notification for %s(%p) is not frozen",
 115                G_STRFUNC, G_OBJECT_TYPE_NAME (object), object);
 116     return;
 117   }
 118
 119   nqueue->freeze_count--;
 120   if (nqueue->freeze_count) {
 121     G_UNLOCK(notify_lock);
 122     return;
 123   }
 124
 125   pspecs = nqueue->n_pspecs > 16 ? free_me = g_new (GParamSpec*, nqueue->n_pspecs) : pspecs_mem;
 126
 127   for (slist = nqueue->pspecs; slist; slist = slist->next)
 128     {
 129       pspecs[n_pspecs++] = slist->data;
 130     }
 131   g_datalist_id_set_data (&object->qdata, context->quark_notify_queue, NULL);
 132
 133   G_UNLOCK(notify_lock);
 134
 135   if (n_pspecs)
 136     context->dispatcher (object, n_pspecs, pspecs);
 137   g_free (free_me);
 138 }
 139
 140 static inline void
 141 g_object_notify_queue_clear (GObject            *object,
 142                              GObjectNotifyQueue *nqueue)
 143 {
 144   g_return_if_fail (nqueue->freeze_count > 0);
 145
 146   G_LOCK(notify_lock);
 147
 148   g_slist_free (nqueue->pspecs);
 149   nqueue->pspecs = NULL;
 150   nqueue->n_pspecs = 0;
 151
 152   G_UNLOCK(notify_lock);
 153 }
 154
 155 static inline void
 156 g_object_notify_queue_add (GObject            *object,
 157                            GObjectNotifyQueue *nqueue,
 158                            GParamSpec         *pspec)
 159 {
 160   if (pspec->flags & G_PARAM_READABLE)
 161     {
 162       GParamSpec *redirect;
 163
 164       G_LOCK(notify_lock);
 165
 166       g_return_if_fail (nqueue->n_pspecs < 65535);
 167
 168       redirect = g_param_spec_get_redirect_target (pspec);
 169       if (redirect)
 170         pspec = redirect;
 171
 172       /* we do the deduping in _thaw */
 173       if (g_slist_find (nqueue->pspecs, pspec) == NULL)
 174         {
 175           nqueue->pspecs = g_slist_prepend (nqueue->pspecs, pspec);
 176           nqueue->n_pspecs++;
 177         }
 178
 179       G_UNLOCK(notify_lock);
 180     }
 181 }
 182
 183 /* NB: This function is not threadsafe, do not ever use it if
 184  * you need a threadsafe notify queue.
 185  * Use g_object_notify_queue_freeze() to acquire the queue and
 186  * g_object_notify_queue_thaw() after you are done instead.
 187  */
 188 static inline GObjectNotifyQueue*
 189 g_object_notify_queue_from_object (GObject              *object,
 190                                    GObjectNotifyContext *context)
 191 {
 192   return g_datalist_id_get_data (&object->qdata, context->quark_notify_queue);
 193 }
 194
 195 G_END_DECLS
 196
 197 #endif /* __G_OBJECT_NOTIFY_QUEUE_H__ */