gthread.c

   1 /* GLIB - Library of useful routines for C programming
   2  * Copyright (C) 1995-1997  Peter Mattis, Spencer Kimball and Josh MacDonald
   3  *
   4  * gmutex.c: MT safety related functions
   5  * Copyright 1998 Sebastian Wilhelmi; University of Karlsruhe
   6  *                Owen Taylor
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2 of the License, or (at your option) any later version.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the
  20  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  21  * Boston, MA 02111-1307, USA.
  22  */
  23
  24 /*
  25  * Modified by the GLib Team and others 1997-2000.  See the AUTHORS
  26  * file for a list of people on the GLib Team.  See the ChangeLog
  27  * files for a list of changes.  These files are distributed with
  28  * GLib at ftp://ftp.gtk.org/pub/gtk/.
  29  */
  30
  31 /*
  32  * MT safe
  33  */
  34
  35 #include "config.h"
  36 #include "glib.h"
  37
  38 #ifdef HAVE_UNISTD_H
  39 #include <unistd.h>
  40 #endif
  41
  42 #if GLIB_SIZEOF_SYSTEM_THREAD == SIZEOF_VOID_P
  43 # define g_system_thread_equal(thread1, thread2)                        \
  44    (thread1.dummy_pointer == thread2.dummy_pointer)
  45 # define g_system_thread_assign(dest, src)                              \
  46    (dest.dummy_pointer = src.dummy_pointer)
  47 #else /* GLIB_SIZEOF_SYSTEM_THREAD != SIZEOF_VOID_P */
  48 # define g_system_thread_equal(thread1, thread2)                        \
  49    (memcmp (&thread1, &thread2, GLIB_SIZEOF_SYSTEM_THREAD) == 0)
  50 # define g_system_thread_assign(dest, src)                              \
  51    (memcpy (&dest, &src, GLIB_SIZEOF_SYSTEM_THREAD))
  52 #endif /* GLIB_SIZEOF_SYSTEM_THREAD == SIZEOF_VOID_P */
  53
  54 GQuark
  55 g_thread_error_quark (void)
  56 {
  57   static GQuark quark;
  58   if (!quark)
  59     quark = g_quark_from_static_string ("g_thread_error");
  60   return quark;
  61 }
  62
  63 typedef struct _GRealThread GRealThread;
  64 struct  _GRealThread
  65 {
  66   GThread thread;
  67   GThreadFunc func;
  68   gpointer arg;
  69   gpointer private_data;
  70   GSystemThread system_thread;
  71 };
  72
  73 typedef struct _GStaticPrivateNode GStaticPrivateNode;
  74 struct _GStaticPrivateNode
  75 {
  76   gpointer       data;
  77   GDestroyNotify destroy;
  78 };
  79
  80 static void g_thread_cleanup (gpointer data);
  81 static void g_thread_fail (void);
  82
  83 /* Global variables */
  84
  85 static GSystemThread zero_thread; /* This is initialized to all zero */
  86 gboolean g_thread_use_default_impl = TRUE;
  87 gboolean g_threads_got_initialized = FALSE;
  88
  89 #if defined(G_OS_WIN32) && defined(__GNUC__)
  90 __declspec(dllexport)
  91 #endif
  92 GThreadFunctions g_thread_functions_for_glib_use = {
  93   (GMutex*(*)())g_thread_fail,                 /* mutex_new */
  94   NULL,                                        /* mutex_lock */
  95   NULL,                                        /* mutex_trylock */
  96   NULL,                                        /* mutex_unlock */
  97   NULL,                                        /* mutex_free */
  98   (GCond*(*)())g_thread_fail,                  /* cond_new */
  99   NULL,                                        /* cond_signal */
 100   NULL,                                        /* cond_broadcast */
 101   NULL,                                        /* cond_wait */
 102   NULL,                                        /* cond_timed_wait  */
 103   NULL,                                        /* cond_free */
 104   (GPrivate*(*)(GDestroyNotify))g_thread_fail, /* private_new */
 105   NULL,                                        /* private_get */
 106   NULL,                                        /* private_set */
 107   (void(*)(GThreadFunc, gpointer, gulong,
 108            gboolean, gboolean, GThreadPriority,
 109            gpointer, GError**))g_thread_fail,  /* thread_create */
 110   NULL,                                        /* thread_yield */
 111   NULL,                                        /* thread_join */
 112   NULL,                                        /* thread_exit */
 113   NULL,                                        /* thread_set_priority */
 114   NULL                                         /* thread_self */
 115 };
 116
 117 /* Local data */
 118
 119 static GMutex   *g_mutex_protect_static_mutex_allocation = NULL;
 120 static GPrivate *g_thread_specific_private = NULL;
 121 static GSList   *g_thread_all_threads = NULL;
 122 static GSList   *g_thread_free_indeces = NULL;
 123
 124 G_LOCK_DEFINE_STATIC (g_thread);
 125
 126 /* This must be called only once, before any threads are created.
 127  * It will only be called from g_thread_init() in -lgthread.
 128  */
 129 void
 130 g_mutex_init (void)
 131 {
 132   GRealThread* main_thread;
 133
 134   /* We let the main thread (the one that calls g_thread_init) inherit
 135    * the data, that it set before calling g_thread_init
 136    */
 137   main_thread = (GRealThread*) g_thread_self ();
 138
 139   g_thread_specific_private = g_private_new (g_thread_cleanup);
 140   G_THREAD_UF (private_set, (g_thread_specific_private, main_thread));
 141   G_THREAD_UF (thread_self, (&main_thread->system_thread));
 142
 143   g_mutex_protect_static_mutex_allocation = g_mutex_new ();
 144 }
 145
 146 void
 147 g_static_mutex_init (GStaticMutex *mutex)
 148 {
 149   static GStaticMutex init_mutex = G_STATIC_MUTEX_INIT;
 150
 151   g_return_if_fail (mutex);
 152
 153   memcpy (mutex, &init_mutex, sizeof (GStaticMutex));
 154 }
 155
 156 GMutex *
 157 g_static_mutex_get_mutex_impl (GMutex** mutex)
 158 {
 159   if (!g_thread_supported ())
 160     return NULL;
 161
 162   g_assert (g_mutex_protect_static_mutex_allocation);
 163
 164   g_mutex_lock (g_mutex_protect_static_mutex_allocation);
 165
 166   if (!(*mutex))
 167     *mutex = g_mutex_new ();
 168
 169   g_mutex_unlock (g_mutex_protect_static_mutex_allocation);
 170
 171   return *mutex;
 172 }
 173
 174 void
 175 g_static_mutex_free (GStaticMutex* mutex)
 176 {
 177   GMutex **runtime_mutex;
 178
 179   g_return_if_fail (mutex);
 180
 181   /* The runtime_mutex is the first (or only) member of GStaticMutex,
 182    * see both versions (of glibconfig.h) in configure.in */
 183   runtime_mutex = ((GMutex**)mutex);
 184
 185   if (*runtime_mutex)
 186     g_mutex_free (*runtime_mutex);
 187
 188   *runtime_mutex = NULL;
 189 }
 190
 191 void
 192 g_static_rec_mutex_init (GStaticRecMutex *mutex)
 193 {
 194   static GStaticRecMutex init_mutex = G_STATIC_REC_MUTEX_INIT;
 195
 196   g_return_if_fail (mutex);
 197
 198   memcpy (mutex, &init_mutex, sizeof (GStaticRecMutex));
 199 }
 200
 201 void
 202 g_static_rec_mutex_lock (GStaticRecMutex* mutex)
 203 {
 204   GSystemThread self;
 205
 206   g_return_if_fail (mutex);
 207
 208   if (!g_thread_supported ())
 209     return;
 210
 211   G_THREAD_UF (thread_self, (&self));
 212
 213   if (g_system_thread_equal (self, mutex->owner))
 214     {
 215       mutex->depth++;
 216       return;
 217     }
 218   g_static_mutex_lock (&mutex->mutex);
 219   g_system_thread_assign (mutex->owner, self);
 220   mutex->depth = 1;
 221 }
 222
 223 gboolean
 224 g_static_rec_mutex_trylock (GStaticRecMutex* mutex)
 225 {
 226   GSystemThread self;
 227
 228   g_return_val_if_fail (mutex, FALSE);
 229
 230   if (!g_thread_supported ())
 231     return TRUE;
 232
 233   G_THREAD_UF (thread_self, (&self));
 234
 235   if (g_system_thread_equal (self, mutex->owner))
 236     {
 237       mutex->depth++;
 238       return TRUE;
 239     }
 240
 241   if (!g_static_mutex_trylock (&mutex->mutex))
 242     return FALSE;
 243
 244   g_system_thread_assign (mutex->owner, self);
 245   mutex->depth = 1;
 246   return TRUE;
 247 }
 248
 249 void
 250 g_static_rec_mutex_unlock (GStaticRecMutex* mutex)
 251 {
 252   g_return_if_fail (mutex);
 253
 254   if (!g_thread_supported ())
 255     return;
 256
 257   if (mutex->depth > 1)
 258     {
 259       mutex->depth--;
 260       return;
 261     }
 262   g_system_thread_assign (mutex->owner, zero_thread);
 263   g_static_mutex_unlock (&mutex->mutex);
 264 }
 265
 266 void
 267 g_static_rec_mutex_lock_full   (GStaticRecMutex *mutex,
 268                                 guint            depth)
 269 {
 270   g_return_if_fail (mutex);
 271
 272   if (!g_thread_supported ())
 273     return;
 274
 275   g_static_mutex_lock (&mutex->mutex);
 276   G_THREAD_UF (thread_self, (&mutex->owner));
 277   mutex->depth = depth;
 278 }
 279
 280 guint
 281 g_static_rec_mutex_unlock_full (GStaticRecMutex *mutex)
 282 {
 283   gint depth;
 284
 285   g_return_val_if_fail (mutex, 0);
 286
 287   if (!g_thread_supported ())
 288     return 1;
 289
 290   depth = mutex->depth;
 291
 292   g_system_thread_assign (mutex->owner, zero_thread);
 293   mutex->depth = 0;
 294   g_static_mutex_unlock (&mutex->mutex);
 295
 296   return depth;
 297 }
 298
 299 void
 300 g_static_rec_mutex_free (GStaticRecMutex *mutex)
 301 {
 302   g_return_if_fail (mutex);
 303
 304   g_static_mutex_free (&mutex->mutex);
 305 }
 306
 307 void
 308 g_static_private_init (GStaticPrivate *private_key)
 309 {
 310   private_key->index = 0;
 311 }
 312
 313 gpointer
 314 g_static_private_get (GStaticPrivate *private_key)
 315 {
 316   return g_static_private_get_for_thread (private_key, g_thread_self ());
 317 }
 318
 319 gpointer
 320 g_static_private_get_for_thread (GStaticPrivate *private_key,
 321                                  GThread        *thread)
 322 {
 323   GArray *array;
 324   GRealThread *self = (GRealThread*) thread;
 325
 326   g_return_val_if_fail (thread, NULL);
 327
 328   array = self->private_data;
 329   if (!array)
 330     return NULL;
 331
 332   if (!private_key->index)
 333     return NULL;
 334   else if (private_key->index <= array->len)
 335     return g_array_index (array, GStaticPrivateNode, private_key->index - 1).data;
 336   else
 337     return NULL;
 338 }
 339
 340 void
 341 g_static_private_set (GStaticPrivate *private_key,
 342                       gpointer        data,
 343                       GDestroyNotify  notify)
 344 {
 345   g_static_private_set_for_thread (private_key, g_thread_self (),
 346                                    data, notify);
 347 }
 348
 349 void
 350 g_static_private_set_for_thread (GStaticPrivate *private_key,
 351                                  GThread        *thread,
 352                                  gpointer        data,
 353                                  GDestroyNotify  notify)
 354 {
 355   GArray *array;
 356   GRealThread *self =(GRealThread*) thread;
 357   static guint next_index = 0;
 358   GStaticPrivateNode *node;
 359
 360   g_return_if_fail (thread);
 361
 362   array = self->private_data;
 363   if (!array)
 364     {
 365       array = g_array_new (FALSE, TRUE, sizeof (GStaticPrivateNode));
 366       self->private_data = array;
 367     }
 368
 369   if (!private_key->index)
 370     {
 371       G_LOCK (g_thread);
 372
 373       if (!private_key->index)
 374         {
 375           if (g_thread_free_indeces)
 376             {
 377               private_key->index =
 378                 GPOINTER_TO_UINT (g_thread_free_indeces->data);
 379               g_thread_free_indeces =
 380                 g_slist_delete_link (g_thread_free_indeces,
 381                                      g_thread_free_indeces);
 382             }
 383           else
 384             private_key->index = ++next_index;
 385         }
 386
 387       G_UNLOCK (g_thread);
 388     }
 389
 390   if (private_key->index > array->len)
 391     g_array_set_size (array, private_key->index);
 392
 393   node = &g_array_index (array, GStaticPrivateNode, private_key->index - 1);
 394   if (node->destroy)
 395     {
 396       gpointer ddata = node->data;
 397       GDestroyNotify ddestroy = node->destroy;
 398
 399       node->data = data;
 400       node->destroy = notify;
 401
 402       ddestroy (ddata);
 403     }
 404   else
 405     {
 406       node->data = data;
 407       node->destroy = notify;
 408     }
 409 }
 410
 411 void
 412 g_static_private_free (GStaticPrivate *private_key)
 413 {
 414   GStaticPrivate copied_key;
 415   GSList *list;
 416
 417   copied_key.index = private_key->index;
 418   private_key->index = 0;
 419
 420   if (!copied_key.index)
 421     return;
 422
 423   G_LOCK (g_thread);
 424   list =  g_thread_all_threads;
 425   while (list)
 426     {
 427       GThread *thread = list->data;
 428       list = list->next;
 429
 430       G_UNLOCK (g_thread);
 431       g_static_private_set_for_thread (&copied_key, thread, NULL, NULL);
 432       G_LOCK (g_thread);
 433     }
 434   g_thread_free_indeces =
 435     g_slist_prepend (g_thread_free_indeces,
 436                      GUINT_TO_POINTER (copied_key.index));
 437   G_UNLOCK (g_thread);
 438 }
 439
 440 static void
 441 g_thread_cleanup (gpointer data)
 442 {
 443   if (data)
 444     {
 445       GRealThread* thread = data;
 446       if (thread->private_data)
 447         {
 448           GArray* array = thread->private_data;
 449           guint i;
 450
 451           for (i = 0; i < array->len; i++ )
 452             {
 453               GStaticPrivateNode *node =
 454                 &g_array_index (array, GStaticPrivateNode, i);
 455               if (node->destroy)
 456                 node->destroy (node->data);
 457             }
 458           g_array_free (array, TRUE);
 459         }
 460       /* We only free the thread structure, if it isn't joinable. If
 461          it is, the structure is freed in g_thread_join */
 462       if (!thread->thread.joinable)
 463         {
 464           G_LOCK (g_thread);
 465           g_thread_all_threads = g_slist_remove (g_thread_all_threads, data);
 466           G_UNLOCK (g_thread);
 467
 468           /* Just to make sure, this isn't used any more */
 469           g_system_thread_assign (thread->system_thread, zero_thread);
 470           g_free (thread);
 471         }
 472     }
 473 }
 474
 475 static void
 476 g_thread_fail (void)
 477 {
 478   g_error ("The thread system is not yet initialized.");
 479 }
 480
 481 static void
 482 g_thread_create_proxy (gpointer data)
 483 {
 484   GRealThread* thread = data;
 485
 486   g_assert (data);
 487
 488   /* This has to happen before G_LOCK, as that might call g_thread_self */
 489   g_private_set (g_thread_specific_private, data);
 490
 491   /* the lock makes sure, that thread->system_thread is written,
 492      before thread->func is called. See g_thread_create. */
 493   G_LOCK (g_thread);
 494   G_UNLOCK (g_thread);
 495
 496   thread->func (thread->arg);
 497 }
 498
 499 GThread*
 500 g_thread_create (GThreadFunc             thread_func,
 501                  gpointer                arg,
 502                  gulong                  stack_size,
 503                  gboolean                joinable,
 504                  gboolean                bound,
 505                  GThreadPriority         priority,
 506                  GError                **error)
 507 {
 508   GRealThread* result = g_new (GRealThread, 1);
 509   GError *local_error = NULL;
 510   g_return_val_if_fail (thread_func, NULL);
 511   g_return_val_if_fail (priority >= G_THREAD_PRIORITY_LOW, NULL);
 512   g_return_val_if_fail (priority <= G_THREAD_PRIORITY_URGENT, NULL);
 513
 514   result->thread.joinable = joinable;
 515   result->thread.bound = bound;
 516   result->thread.priority = priority;
 517   result->func = thread_func;
 518   result->arg = arg;
 519   result->private_data = NULL;
 520   G_LOCK (g_thread);
 521   G_THREAD_UF (thread_create, (g_thread_create_proxy, result,
 522                                stack_size, joinable, bound, priority,
 523                                &result->system_thread, &local_error));
 524   g_thread_all_threads = g_slist_prepend (g_thread_all_threads, result);
 525   G_UNLOCK (g_thread);
 526
 527   if (local_error)
 528     {
 529       g_propagate_error (error, local_error);
 530       g_free (result);
 531       return NULL;
 532     }
 533
 534   return (GThread*) result;
 535 }
 536
 537 void
 538 g_thread_join (GThread* thread)
 539 {
 540   GRealThread* real = (GRealThread*) thread;
 541
 542
 543   g_return_if_fail (thread);
 544   g_return_if_fail (thread->joinable);
 545   g_return_if_fail (!g_system_thread_equal (real->system_thread, zero_thread));
 546
 547   G_THREAD_UF (thread_join, (&real->system_thread));
 548
 549   G_LOCK (g_thread);
 550   g_thread_all_threads = g_slist_remove (g_thread_all_threads, thread);
 551   G_UNLOCK (g_thread);
 552
 553   /* Just to make sure, this isn't used any more */
 554   thread->joinable = 0;
 555   g_system_thread_assign (real->system_thread, zero_thread);
 556
 557   /* the thread structure for non-joinable threads is freed upon
 558      thread end. We free the memory here. This will leave loose end,
 559      if a joinable thread is not joined. */
 560
 561   g_free (thread);
 562 }
 563
 564 void
 565 g_thread_set_priority (GThread* thread,
 566                        GThreadPriority priority)
 567 {
 568   GRealThread* real = (GRealThread*) thread;
 569
 570   g_return_if_fail (thread);
 571   g_return_if_fail (!g_system_thread_equal (real->system_thread, zero_thread));
 572   g_return_if_fail (priority >= G_THREAD_PRIORITY_LOW);
 573   g_return_if_fail (priority <= G_THREAD_PRIORITY_URGENT);
 574
 575   thread->priority = priority;
 576   G_THREAD_CF (thread_set_priority, (void)0, (&real->system_thread, priority));
 577 }
 578
 579 GThread*
 580 g_thread_self (void)
 581 {
 582   GRealThread* thread = g_private_get (g_thread_specific_private);
 583
 584   if (!thread)
 585     {
 586       /* If no thread data is available, provide and set one.  This
 587          can happen for the main thread and for threads, that are not
 588          created by GLib. */
 589       thread = g_new (GRealThread, 1);
 590       thread->thread.joinable = FALSE; /* This is a save guess */
 591       thread->thread.bound = TRUE; /* This isn't important at all */
 592       thread->thread.priority = G_THREAD_PRIORITY_NORMAL; /* This is
 593                                                              just a guess */
 594       thread->func = NULL;
 595       thread->arg = NULL;
 596       thread->private_data = NULL;
 597
 598       if (g_thread_supported ())
 599         G_THREAD_UF (thread_self, (&thread->system_thread));
 600
 601       g_private_set (g_thread_specific_private, thread);
 602
 603       G_LOCK (g_thread);
 604       g_thread_all_threads = g_slist_prepend (g_thread_all_threads, thread);
 605       G_UNLOCK (g_thread);
 606     }
 607
 608   return (GThread*)thread;
 609 }
 610
 611 void
 612 g_static_rw_lock_init (GStaticRWLock* lock)
 613 {
 614   static GStaticRWLock init_lock = G_STATIC_RW_LOCK_INIT;
 615
 616   g_return_if_fail (lock);
 617
 618   memcpy (lock, &init_lock, sizeof (GStaticRWLock));
 619 }
 620
 621 static void inline
 622 g_static_rw_lock_wait (GCond** cond, GStaticMutex* mutex)
 623 {
 624   if (!*cond)
 625       *cond = g_cond_new ();
 626   g_cond_wait (*cond, g_static_mutex_get_mutex (mutex));
 627 }
 628
 629 static void inline
 630 g_static_rw_lock_signal (GStaticRWLock* lock)
 631 {
 632   if (lock->want_to_write && lock->write_cond)
 633     g_cond_signal (lock->write_cond);
 634   else if (lock->read_cond)
 635     g_cond_broadcast (lock->read_cond);
 636 }
 637
 638 void
 639 g_static_rw_lock_reader_lock (GStaticRWLock* lock)
 640 {
 641   g_return_if_fail (lock);
 642
 643   if (!g_threads_got_initialized)
 644     return;
 645
 646   g_static_mutex_lock (&lock->mutex);
 647   while (lock->write || lock->want_to_write)
 648     g_static_rw_lock_wait (&lock->read_cond, &lock->mutex);
 649   lock->read_counter++;
 650   g_static_mutex_unlock (&lock->mutex);
 651 }
 652
 653 gboolean
 654 g_static_rw_lock_reader_trylock (GStaticRWLock* lock)
 655 {
 656   gboolean ret_val = FALSE;
 657
 658   g_return_val_if_fail (lock, FALSE);
 659
 660   if (!g_threads_got_initialized)
 661     return TRUE;
 662
 663   g_static_mutex_lock (&lock->mutex);
 664   if (!lock->write && !lock->want_to_write)
 665     {
 666       lock->read_counter++;
 667       ret_val = TRUE;
 668     }
 669   g_static_mutex_unlock (&lock->mutex);
 670   return ret_val;
 671 }
 672
 673 void
 674 g_static_rw_lock_reader_unlock  (GStaticRWLock* lock)
 675 {
 676   g_return_if_fail (lock);
 677
 678   if (!g_threads_got_initialized)
 679     return;
 680
 681   g_static_mutex_lock (&lock->mutex);
 682   lock->read_counter--;
 683   if (lock->read_counter == 0)
 684     g_static_rw_lock_signal (lock);
 685   g_static_mutex_unlock (&lock->mutex);
 686 }
 687
 688 void
 689 g_static_rw_lock_writer_lock (GStaticRWLock* lock)
 690 {
 691   g_return_if_fail (lock);
 692
 693   if (!g_threads_got_initialized)
 694     return;
 695
 696   g_static_mutex_lock (&lock->mutex);
 697   lock->want_to_write++;
 698   while (lock->write || lock->read_counter)
 699     g_static_rw_lock_wait (&lock->write_cond, &lock->mutex);
 700   lock->want_to_write--;
 701   lock->write = TRUE;
 702   g_static_mutex_unlock (&lock->mutex);
 703 }
 704
 705 gboolean
 706 g_static_rw_lock_writer_trylock (GStaticRWLock* lock)
 707 {
 708   gboolean ret_val = FALSE;
 709
 710   g_return_val_if_fail (lock, FALSE);
 711
 712   if (!g_threads_got_initialized)
 713     return TRUE;
 714
 715   g_static_mutex_lock (&lock->mutex);
 716   if (!lock->write && !lock->read_counter)
 717     {
 718       lock->write = TRUE;
 719       ret_val = TRUE;
 720     }
 721   g_static_mutex_unlock (&lock->mutex);
 722   return ret_val;
 723 }
 724
 725 void
 726 g_static_rw_lock_writer_unlock (GStaticRWLock* lock)
 727 {
 728   g_return_if_fail (lock);
 729
 730   if (!g_threads_got_initialized)
 731     return;
 732
 733   g_static_mutex_lock (&lock->mutex);
 734   lock->write = FALSE;
 735   g_static_rw_lock_signal (lock);
 736   g_static_mutex_unlock (&lock->mutex);
 737 }
 738
 739 void
 740 g_static_rw_lock_free (GStaticRWLock* lock)
 741 {
 742   g_return_if_fail (lock);
 743
 744   if (lock->read_cond)
 745     {
 746       g_cond_free (lock->read_cond);
 747       lock->read_cond = NULL;
 748     }
 749   if (lock->write_cond)
 750     {
 751       g_cond_free (lock->write_cond);
 752       lock->write_cond = NULL;
 753     }
 754   g_static_mutex_free (&lock->mutex);
 755 }