gobject/gclosure.c

   1 /* GObject - GLib Type, Object, Parameter and Signal Library
   2  * Copyright (C) 2000-2001 Red Hat, Inc.
   3  * Copyright (C) 2005 Imendio AB
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General
  16  * Public License along with this library; if not, write to the
  17  * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  18  * Boston, MA 02111-1307, USA.
  19  */
  20 #include        "gclosure.h"
  21
  22 /*
  23  * MT safe with regards to reference counting.
  24  */
  25
  26 #include        "gvalue.h"
  27 #include        "gobjectalias.h"
  28 #include        <string.h>
  29
  30
  31 #define CLOSURE_MAX_REF_COUNT           ((1 << 15) - 1)
  32 #define CLOSURE_MAX_N_GUARDS            ((1 << 1) - 1)
  33 #define CLOSURE_MAX_N_FNOTIFIERS        ((1 << 2) - 1)
  34 #define CLOSURE_MAX_N_INOTIFIERS        ((1 << 8) - 1)
  35 #define CLOSURE_N_MFUNCS(cl)            ((cl)->meta_marshal + \
  36                                          ((cl)->n_guards << 1L))
  37 /* same as G_CLOSURE_N_NOTIFIERS() (keep in sync) */
  38 #define CLOSURE_N_NOTIFIERS(cl)         (CLOSURE_N_MFUNCS (cl) + \
  39                                          (cl)->n_fnotifiers + \
  40                                          (cl)->n_inotifiers)
  41
  42 typedef union {
  43   GClosure closure;
  44   volatile gint vint;
  45 } ClosureInt;
  46
  47 #define CHANGE_FIELD(_closure, _field, _OP, _value, _must_set, _SET_OLD, _SET_NEW)      \
  48 G_STMT_START {                                                                          \
  49   ClosureInt *cunion = (ClosureInt*) _closure;                                          \
  50   gint new_int, old_int, success;                                                       \
  51   do                                                                                    \
  52     {                                                                                   \
  53       ClosureInt tmp;                                                                   \
  54       tmp.vint = old_int = cunion->vint;                                                \
  55       _SET_OLD tmp.closure._field;                                                      \
  56       tmp.closure._field _OP _value;                                                    \
  57       _SET_NEW tmp.closure._field;                                                      \
  58       new_int = tmp.vint;                                                               \
  59       success = g_atomic_int_compare_and_exchange (&cunion->vint, old_int, new_int);    \
  60     }                                                                                   \
  61   while (!success && _must_set);                                                        \
  62 } G_STMT_END
  63
  64 #define SWAP(_closure, _field, _value, _oldv)   CHANGE_FIELD (_closure, _field, =, _value, TRUE, *(_oldv) =,     (void) )
  65 #define SET(_closure, _field, _value)           CHANGE_FIELD (_closure, _field, =, _value, TRUE,     (void),     (void) )
  66 #define INC(_closure, _field)                   CHANGE_FIELD (_closure, _field, +=,     1, TRUE,     (void),     (void) )
  67 #define INC_ASSIGN(_closure, _field, _newv)     CHANGE_FIELD (_closure, _field, +=,     1, TRUE,     (void), *(_newv) = )
  68 #define DEC(_closure, _field)                   CHANGE_FIELD (_closure, _field, -=,     1, TRUE,     (void),     (void) )
  69 #define DEC_ASSIGN(_closure, _field, _newv)     CHANGE_FIELD (_closure, _field, -=,     1, TRUE,     (void), *(_newv) = )
  70
  71 #if 0   // for non-thread-safe closures
  72 #define SWAP(cl,f,v,o)     (void) (*(o) = cl->f, cl->f = v)
  73 #define SET(cl,f,v)        (void) (cl->f = v)
  74 #define INC(cl,f)          (void) (cl->f += 1)
  75 #define INC_ASSIGN(cl,f,n) (void) (cl->f += 1, *(n) = cl->f)
  76 #define DEC(cl,f)          (void) (cl->f -= 1)
  77 #define DEC_ASSIGN(cl,f,n) (void) (cl->f -= 1, *(n) = cl->f)
  78 #endif
  79
  80 enum {
  81   FNOTIFY,
  82   INOTIFY,
  83   PRE_NOTIFY,
  84   POST_NOTIFY
  85 };
  86
  87
  88 /* --- functions --- */
  89 GClosure*
  90 g_closure_new_simple (guint           sizeof_closure,
  91                       gpointer        data)
  92 {
  93   GClosure *closure;
  94
  95   g_return_val_if_fail (sizeof_closure >= sizeof (GClosure), NULL);
  96
  97   closure = g_malloc0 (sizeof_closure);
  98   SET (closure, ref_count, 1);
  99   SET (closure, meta_marshal, 0);
 100   SET (closure, n_guards, 0);
 101   SET (closure, n_fnotifiers, 0);
 102   SET (closure, n_inotifiers, 0);
 103   SET (closure, in_inotify, FALSE);
 104   SET (closure, floating, TRUE);
 105   SET (closure, derivative_flag, 0);
 106   SET (closure, in_marshal, FALSE);
 107   SET (closure, is_invalid, FALSE);
 108   closure->marshal = NULL;
 109   closure->data = data;
 110   closure->notifiers = NULL;
 111   memset (G_STRUCT_MEMBER_P (closure, sizeof (*closure)), 0, sizeof_closure - sizeof (*closure));
 112
 113   return closure;
 114 }
 115
 116 static inline void
 117 closure_invoke_notifiers (GClosure *closure,
 118                           guint     notify_type)
 119 {
 120   /* notifier layout:
 121    *     meta_marshal  n_guards    n_guards     n_fnotif.  n_inotifiers
 122    * ->[[meta_marshal][pre_guards][post_guards][fnotifiers][inotifiers]]
 123    *
 124    * CLOSURE_N_MFUNCS(cl)    = meta_marshal + n_guards + n_guards;
 125    * CLOSURE_N_NOTIFIERS(cl) = CLOSURE_N_MFUNCS(cl) + n_fnotifiers + n_inotifiers
 126    *
 127    * constrains/catches:
 128    * - closure->notifiers may be reloacted during callback
 129    * - closure->n_fnotifiers and closure->n_inotifiers may change during callback
 130    * - i.e. callbacks can be removed/added during invocation
 131    * - must prepare for callback removal during FNOTIFY and INOTIFY (done via ->marshal= & ->data=)
 132    * - must distinguish (->marshal= & ->data=) for INOTIFY vs. FNOTIFY (via ->in_inotify)
 133    * + closure->n_guards is const during PRE_NOTIFY & POST_NOTIFY
 134    * + closure->meta_marshal is const for all cases
 135    * + none of the callbacks can cause recursion
 136    * + closure->n_inotifiers is const 0 during FNOTIFY
 137    */
 138   switch (notify_type)
 139     {
 140       GClosureNotifyData *ndata;
 141       guint i, offs;
 142     case FNOTIFY:
 143       while (closure->n_fnotifiers)
 144         {
 145           guint n;
 146           DEC_ASSIGN (closure, n_fnotifiers, &n);
 147
 148           ndata = closure->notifiers + CLOSURE_N_MFUNCS (closure) + n;
 149           closure->marshal = (GClosureMarshal) ndata->notify;
 150           closure->data = ndata->data;
 151           ndata->notify (ndata->data, closure);
 152         }
 153       closure->marshal = NULL;
 154       closure->data = NULL;
 155       break;
 156     case INOTIFY:
 157       SET (closure, in_inotify, TRUE);
 158       while (closure->n_inotifiers)
 159         {
 160           guint n;
 161           DEC_ASSIGN (closure, n_inotifiers, &n);
 162
 163           ndata = closure->notifiers + CLOSURE_N_MFUNCS (closure) + closure->n_fnotifiers + n;
 164           closure->marshal = (GClosureMarshal) ndata->notify;
 165           closure->data = ndata->data;
 166           ndata->notify (ndata->data, closure);
 167         }
 168       closure->marshal = NULL;
 169       closure->data = NULL;
 170       SET (closure, in_inotify, FALSE);
 171       break;
 172     case PRE_NOTIFY:
 173       i = closure->n_guards;
 174       offs = closure->meta_marshal;
 175       while (i--)
 176         {
 177           ndata = closure->notifiers + offs + i;
 178           ndata->notify (ndata->data, closure);
 179         }
 180       break;
 181     case POST_NOTIFY:
 182       i = closure->n_guards;
 183       offs = closure->meta_marshal + i;
 184       while (i--)
 185         {
 186           ndata = closure->notifiers + offs + i;
 187           ndata->notify (ndata->data, closure);
 188         }
 189       break;
 190     }
 191 }
 192
 193 void
 194 g_closure_set_meta_marshal (GClosure       *closure,
 195                             gpointer        marshal_data,
 196                             GClosureMarshal meta_marshal)
 197 {
 198   GClosureNotifyData *notifiers;
 199   guint n;
 200
 201   g_return_if_fail (closure != NULL);
 202   g_return_if_fail (meta_marshal != NULL);
 203   g_return_if_fail (closure->is_invalid == FALSE);
 204   g_return_if_fail (closure->in_marshal == FALSE);
 205   g_return_if_fail (closure->meta_marshal == 0);
 206
 207   n = CLOSURE_N_NOTIFIERS (closure);
 208   notifiers = closure->notifiers;
 209   closure->notifiers = g_renew (GClosureNotifyData, NULL, CLOSURE_N_NOTIFIERS (closure) + 1);
 210   if (notifiers)
 211     {
 212       /* usually the meta marshal will be setup right after creation, so the
 213        * g_memmove() should be rare-case scenario
 214        */
 215       g_memmove (closure->notifiers + 1, notifiers, CLOSURE_N_NOTIFIERS (closure) * sizeof (notifiers[0]));
 216       g_free (notifiers);
 217     }
 218   closure->notifiers[0].data = marshal_data;
 219   closure->notifiers[0].notify = (GClosureNotify) meta_marshal;
 220   SET (closure, meta_marshal, 1);
 221 }
 222
 223 void
 224 g_closure_add_marshal_guards (GClosure      *closure,
 225                               gpointer       pre_marshal_data,
 226                               GClosureNotify pre_marshal_notify,
 227                               gpointer       post_marshal_data,
 228                               GClosureNotify post_marshal_notify)
 229 {
 230   guint i;
 231
 232   g_return_if_fail (closure != NULL);
 233   g_return_if_fail (pre_marshal_notify != NULL);
 234   g_return_if_fail (post_marshal_notify != NULL);
 235   g_return_if_fail (closure->is_invalid == FALSE);
 236   g_return_if_fail (closure->in_marshal == FALSE);
 237   g_return_if_fail (closure->n_guards < CLOSURE_MAX_N_GUARDS);
 238
 239   closure->notifiers = g_renew (GClosureNotifyData, closure->notifiers, CLOSURE_N_NOTIFIERS (closure) + 2);
 240   if (closure->n_inotifiers)
 241     closure->notifiers[(CLOSURE_N_MFUNCS (closure) +
 242                         closure->n_fnotifiers +
 243                         closure->n_inotifiers + 1)] = closure->notifiers[(CLOSURE_N_MFUNCS (closure) +
 244                                                                           closure->n_fnotifiers + 0)];
 245   if (closure->n_inotifiers > 1)
 246     closure->notifiers[(CLOSURE_N_MFUNCS (closure) +
 247                         closure->n_fnotifiers +
 248                         closure->n_inotifiers)] = closure->notifiers[(CLOSURE_N_MFUNCS (closure) +
 249                                                                       closure->n_fnotifiers + 1)];
 250   if (closure->n_fnotifiers)
 251     closure->notifiers[(CLOSURE_N_MFUNCS (closure) +
 252                         closure->n_fnotifiers + 1)] = closure->notifiers[CLOSURE_N_MFUNCS (closure) + 0];
 253   if (closure->n_fnotifiers > 1)
 254     closure->notifiers[(CLOSURE_N_MFUNCS (closure) +
 255                         closure->n_fnotifiers)] = closure->notifiers[CLOSURE_N_MFUNCS (closure) + 1];
 256   if (closure->n_guards)
 257     closure->notifiers[(closure->meta_marshal +
 258                         closure->n_guards +
 259                         closure->n_guards + 1)] = closure->notifiers[closure->meta_marshal + closure->n_guards];
 260   i = closure->n_guards;
 261   closure->notifiers[closure->meta_marshal + i].data = pre_marshal_data;
 262   closure->notifiers[closure->meta_marshal + i].notify = pre_marshal_notify;
 263   closure->notifiers[closure->meta_marshal + i + 1].data = post_marshal_data;
 264   closure->notifiers[closure->meta_marshal + i + 1].notify = post_marshal_notify;
 265   INC (closure, n_guards);
 266 }
 267
 268 void
 269 g_closure_add_finalize_notifier (GClosure      *closure,
 270                                  gpointer       notify_data,
 271                                  GClosureNotify notify_func)
 272 {
 273   guint i;
 274
 275   g_return_if_fail (closure != NULL);
 276   g_return_if_fail (notify_func != NULL);
 277   g_return_if_fail (closure->n_fnotifiers < CLOSURE_MAX_N_FNOTIFIERS);
 278
 279   closure->notifiers = g_renew (GClosureNotifyData, closure->notifiers, CLOSURE_N_NOTIFIERS (closure) + 1);
 280   if (closure->n_inotifiers)
 281     closure->notifiers[(CLOSURE_N_MFUNCS (closure) +
 282                         closure->n_fnotifiers +
 283                         closure->n_inotifiers)] = closure->notifiers[(CLOSURE_N_MFUNCS (closure) +
 284                                                                       closure->n_fnotifiers + 0)];
 285   i = CLOSURE_N_MFUNCS (closure) + closure->n_fnotifiers;
 286   closure->notifiers[i].data = notify_data;
 287   closure->notifiers[i].notify = notify_func;
 288   INC (closure, n_fnotifiers);
 289 }
 290
 291 void
 292 g_closure_add_invalidate_notifier (GClosure      *closure,
 293                                    gpointer       notify_data,
 294                                    GClosureNotify notify_func)
 295 {
 296   guint i;
 297
 298   g_return_if_fail (closure != NULL);
 299   g_return_if_fail (notify_func != NULL);
 300   g_return_if_fail (closure->is_invalid == FALSE);
 301   g_return_if_fail (closure->n_inotifiers < CLOSURE_MAX_N_INOTIFIERS);
 302
 303   closure->notifiers = g_renew (GClosureNotifyData, closure->notifiers, CLOSURE_N_NOTIFIERS (closure) + 1);
 304   i = CLOSURE_N_MFUNCS (closure) + closure->n_fnotifiers + closure->n_inotifiers;
 305   closure->notifiers[i].data = notify_data;
 306   closure->notifiers[i].notify = notify_func;
 307   INC (closure, n_inotifiers);
 308 }
 309
 310 static inline gboolean
 311 closure_try_remove_inotify (GClosure       *closure,
 312                             gpointer       notify_data,
 313                             GClosureNotify notify_func)
 314 {
 315   GClosureNotifyData *ndata, *nlast;
 316
 317   nlast = closure->notifiers + CLOSURE_N_NOTIFIERS (closure) - 1;
 318   for (ndata = nlast + 1 - closure->n_inotifiers; ndata <= nlast; ndata++)
 319     if (ndata->notify == notify_func && ndata->data == notify_data)
 320       {
 321         DEC (closure, n_inotifiers);
 322         if (ndata < nlast)
 323           *ndata = *nlast;
 324
 325         return TRUE;
 326       }
 327   return FALSE;
 328 }
 329
 330 static inline gboolean
 331 closure_try_remove_fnotify (GClosure       *closure,
 332                             gpointer       notify_data,
 333                             GClosureNotify notify_func)
 334 {
 335   GClosureNotifyData *ndata, *nlast;
 336
 337   nlast = closure->notifiers + CLOSURE_N_NOTIFIERS (closure) - closure->n_inotifiers - 1;
 338   for (ndata = nlast + 1 - closure->n_fnotifiers; ndata <= nlast; ndata++)
 339     if (ndata->notify == notify_func && ndata->data == notify_data)
 340       {
 341         DEC (closure, n_fnotifiers);
 342         if (ndata < nlast)
 343           *ndata = *nlast;
 344         if (closure->n_inotifiers)
 345           closure->notifiers[(CLOSURE_N_MFUNCS (closure) +
 346                               closure->n_fnotifiers)] = closure->notifiers[(CLOSURE_N_MFUNCS (closure) +
 347                                                                             closure->n_fnotifiers +
 348                                                                             closure->n_inotifiers)];
 349         return TRUE;
 350       }
 351   return FALSE;
 352 }
 353
 354 GClosure*
 355 g_closure_ref (GClosure *closure)
 356 {
 357   guint new_ref_count;
 358   g_return_val_if_fail (closure != NULL, NULL);
 359   g_return_val_if_fail (closure->ref_count > 0, NULL);
 360   g_return_val_if_fail (closure->ref_count < CLOSURE_MAX_REF_COUNT, NULL);
 361
 362   INC_ASSIGN (closure, ref_count, &new_ref_count);
 363   g_return_val_if_fail (new_ref_count > 1, NULL);
 364
 365   return closure;
 366 }
 367
 368 void
 369 g_closure_invalidate (GClosure *closure)
 370 {
 371   g_return_if_fail (closure != NULL);
 372
 373   if (!closure->is_invalid)
 374     {
 375       gboolean was_invalid;
 376       g_closure_ref (closure);           /* preserve floating flag */
 377       SWAP (closure, is_invalid, TRUE, &was_invalid);
 378       /* invalidate only once */
 379       if (!was_invalid)
 380         closure_invoke_notifiers (closure, INOTIFY);
 381       g_closure_unref (closure);
 382     }
 383 }
 384
 385 void
 386 g_closure_unref (GClosure *closure)
 387 {
 388   guint new_ref_count;
 389
 390   g_return_if_fail (closure != NULL);
 391   g_return_if_fail (closure->ref_count > 0);
 392
 393   if (closure->ref_count == 1)  /* last unref, invalidate first */
 394     g_closure_invalidate (closure);
 395
 396   DEC_ASSIGN (closure, ref_count, &new_ref_count);
 397
 398   if (new_ref_count == 0)
 399     {
 400       closure_invoke_notifiers (closure, FNOTIFY);
 401       g_free (closure->notifiers);
 402       g_free (closure);
 403     }
 404 }
 405
 406 void
 407 g_closure_sink (GClosure *closure)
 408 {
 409   g_return_if_fail (closure != NULL);
 410   g_return_if_fail (closure->ref_count > 0);
 411
 412   /* floating is basically a kludge to avoid creating closures
 413    * with a ref_count of 0. so the intial ref_count a closure has
 414    * is unowned. with invoking g_closure_sink() code may
 415    * indicate that it takes over that intiial ref_count.
 416    */
 417   if (closure->floating)
 418     {
 419       gboolean was_floating;
 420       SWAP (closure, floating, FALSE, &was_floating);
 421       /* unref floating flag only once */
 422       if (was_floating)
 423         g_closure_unref (closure);
 424     }
 425 }
 426
 427 void
 428 g_closure_remove_invalidate_notifier (GClosure      *closure,
 429                                       gpointer       notify_data,
 430                                       GClosureNotify notify_func)
 431 {
 432   g_return_if_fail (closure != NULL);
 433   g_return_if_fail (notify_func != NULL);
 434
 435   if (closure->is_invalid && closure->in_inotify && /* account removal of notify_func() while its called */
 436       ((gpointer) closure->marshal) == ((gpointer) notify_func) &&
 437       closure->data == notify_data)
 438     closure->marshal = NULL;
 439   else if (!closure_try_remove_inotify (closure, notify_data, notify_func))
 440     g_warning (G_STRLOC ": unable to remove uninstalled invalidation notifier: %p (%p)",
 441                notify_func, notify_data);
 442 }
 443
 444 void
 445 g_closure_remove_finalize_notifier (GClosure      *closure,
 446                                     gpointer       notify_data,
 447                                     GClosureNotify notify_func)
 448 {
 449   g_return_if_fail (closure != NULL);
 450   g_return_if_fail (notify_func != NULL);
 451
 452   if (closure->is_invalid && !closure->in_inotify && /* account removal of notify_func() while its called */
 453       ((gpointer) closure->marshal) == ((gpointer) notify_func) &&
 454       closure->data == notify_data)
 455     closure->marshal = NULL;
 456   else if (!closure_try_remove_fnotify (closure, notify_data, notify_func))
 457     g_warning (G_STRLOC ": unable to remove uninstalled finalization notifier: %p (%p)",
 458                notify_func, notify_data);
 459 }
 460
 461 void
 462 g_closure_invoke (GClosure       *closure,
 463                   GValue /*out*/ *return_value,
 464                   guint           n_param_values,
 465                   const GValue   *param_values,
 466                   gpointer        invocation_hint)
 467 {
 468   g_return_if_fail (closure != NULL);
 469
 470   g_closure_ref (closure);      /* preserve floating flag */
 471   if (!closure->is_invalid)
 472     {
 473       GClosureMarshal marshal;
 474       gpointer marshal_data;
 475       gboolean in_marshal = closure->in_marshal;
 476
 477       g_return_if_fail (closure->marshal || closure->meta_marshal);
 478
 479       SET (closure, in_marshal, TRUE);
 480       if (closure->meta_marshal)
 481         {
 482           marshal_data = closure->notifiers[0].data;
 483           marshal = (GClosureMarshal) closure->notifiers[0].notify;
 484         }
 485       else
 486         {
 487           marshal_data = NULL;
 488           marshal = closure->marshal;
 489         }
 490       if (!in_marshal)
 491         closure_invoke_notifiers (closure, PRE_NOTIFY);
 492       marshal (closure,
 493                return_value,
 494                n_param_values, param_values,
 495                invocation_hint,
 496                marshal_data);
 497       if (!in_marshal)
 498         closure_invoke_notifiers (closure, POST_NOTIFY);
 499       SET (closure, in_marshal, in_marshal);
 500     }
 501   g_closure_unref (closure);
 502 }
 503
 504 void
 505 g_closure_set_marshal (GClosure       *closure,
 506                        GClosureMarshal marshal)
 507 {
 508   g_return_if_fail (closure != NULL);
 509   g_return_if_fail (marshal != NULL);
 510
 511   if (closure->marshal && closure->marshal != marshal)
 512     g_warning ("attempt to override closure->marshal (%p) with new marshal (%p)",
 513                closure->marshal, marshal);
 514   else
 515     closure->marshal = marshal;
 516 }
 517
 518 GClosure*
 519 g_cclosure_new (GCallback      callback_func,
 520                 gpointer       user_data,
 521                 GClosureNotify destroy_data)
 522 {
 523   GClosure *closure;
 524
 525   g_return_val_if_fail (callback_func != NULL, NULL);
 526
 527   closure = g_closure_new_simple (sizeof (GCClosure), user_data);
 528   if (destroy_data)
 529     g_closure_add_finalize_notifier (closure, user_data, destroy_data);
 530   ((GCClosure*) closure)->callback = (gpointer) callback_func;
 531
 532   return closure;
 533 }
 534
 535 GClosure*
 536 g_cclosure_new_swap (GCallback      callback_func,
 537                      gpointer       user_data,
 538                      GClosureNotify destroy_data)
 539 {
 540   GClosure *closure;
 541
 542   g_return_val_if_fail (callback_func != NULL, NULL);
 543
 544   closure = g_closure_new_simple (sizeof (GCClosure), user_data);
 545   if (destroy_data)
 546     g_closure_add_finalize_notifier (closure, user_data, destroy_data);
 547   ((GCClosure*) closure)->callback = (gpointer) callback_func;
 548   SET (closure, derivative_flag, TRUE);
 549
 550   return closure;
 551 }
 552
 553 static void
 554 g_type_class_meta_marshal (GClosure       *closure,
 555                            GValue /*out*/ *return_value,
 556                            guint           n_param_values,
 557                            const GValue   *param_values,
 558                            gpointer        invocation_hint,
 559                            gpointer        marshal_data)
 560 {
 561   GTypeClass *class;
 562   gpointer callback;
 563   /* GType itype = (GType) closure->data; */
 564   guint offset = GPOINTER_TO_UINT (marshal_data);
 565
 566   class = G_TYPE_INSTANCE_GET_CLASS (g_value_peek_pointer (param_values + 0), itype, GTypeClass);
 567   callback = G_STRUCT_MEMBER (gpointer, class, offset);
 568   if (callback)
 569     closure->marshal (closure,
 570                       return_value,
 571                       n_param_values, param_values,
 572                       invocation_hint,
 573                       callback);
 574 }
 575
 576 static void
 577 g_type_iface_meta_marshal (GClosure       *closure,
 578                            GValue /*out*/ *return_value,
 579                            guint           n_param_values,
 580                            const GValue   *param_values,
 581                            gpointer        invocation_hint,
 582                            gpointer        marshal_data)
 583 {
 584   GTypeClass *class;
 585   gpointer callback;
 586   GType itype = (GType) closure->data;
 587   guint offset = GPOINTER_TO_UINT (marshal_data);
 588
 589   class = G_TYPE_INSTANCE_GET_INTERFACE (g_value_peek_pointer (param_values + 0), itype, GTypeClass);
 590   callback = G_STRUCT_MEMBER (gpointer, class, offset);
 591   if (callback)
 592     closure->marshal (closure,
 593                       return_value,
 594                       n_param_values, param_values,
 595                       invocation_hint,
 596                       callback);
 597 }
 598
 599 GClosure*
 600 g_signal_type_cclosure_new (GType    itype,
 601                             guint    struct_offset)
 602 {
 603   GClosure *closure;
 604
 605   g_return_val_if_fail (G_TYPE_IS_CLASSED (itype) || G_TYPE_IS_INTERFACE (itype), NULL);
 606   g_return_val_if_fail (struct_offset >= sizeof (GTypeClass), NULL);
 607
 608   closure = g_closure_new_simple (sizeof (GClosure), (gpointer) itype);
 609   if (G_TYPE_IS_INTERFACE (itype))
 610     g_closure_set_meta_marshal (closure, GUINT_TO_POINTER (struct_offset), g_type_iface_meta_marshal);
 611   else
 612     g_closure_set_meta_marshal (closure, GUINT_TO_POINTER (struct_offset), g_type_class_meta_marshal);
 613
 614   return closure;
 615 }
 616
 617 #define __G_CLOSURE_C__
 618 #include "gobjectaliasdef.c"