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 G_THREAD_USE_PID_SURROGATE
  39 #include <sys/types.h>
  40 #include <sys/time.h>
  41 #include <sys/resource.h>
  42 #include <errno.h>
  43 #endif /* G_THREAD_USE_PID_SURROGATE */
  44
  45 #ifdef HAVE_UNISTD_H
  46 #include <unistd.h>
  47 #endif
  48
  49 #include <string.h>
  50
  51 #if GLIB_SIZEOF_SYSTEM_THREAD == SIZEOF_VOID_P
  52 # define g_system_thread_equal(thread1, thread2)                        \
  53    (thread1.dummy_pointer == thread2.dummy_pointer)
  54 # define g_system_thread_assign(dest, src)                              \
  55    (dest.dummy_pointer = src.dummy_pointer)
  56 #else /* GLIB_SIZEOF_SYSTEM_THREAD != SIZEOF_VOID_P */
  57 # define g_system_thread_equal(thread1, thread2)                        \
  58    (memcmp (&thread1, &thread2, GLIB_SIZEOF_SYSTEM_THREAD) == 0)
  59 # define g_system_thread_assign(dest, src)                              \
  60    (memcpy (&dest, &src, GLIB_SIZEOF_SYSTEM_THREAD))
  61 #endif /* GLIB_SIZEOF_SYSTEM_THREAD == SIZEOF_VOID_P */
  62
  63 GQuark
  64 g_thread_error_quark (void)
  65 {
  66   static GQuark quark;
  67   if (!quark)
  68     quark = g_quark_from_static_string ("g_thread_error");
  69   return quark;
  70 }
  71
  72 typedef struct _GRealThread GRealThread;
  73 struct  _GRealThread
  74 {
  75   GThread thread;
  76   GThreadFunc func;
  77   gpointer arg;
  78   gpointer private_data;
  79   GSystemThread system_thread;
  80 #ifdef G_THREAD_USE_PID_SURROGATE
  81   pid_t pid;
  82 #endif /* G_THREAD_USE_PID_SURROGATE */
  83 };
  84
  85 #ifdef G_THREAD_USE_PID_SURROGATE
  86 static gint priority_map[] = { 15, 0, -15, -20 };
  87 static gboolean prio_warned = FALSE;
  88 # define SET_PRIO(pid, prio) G_STMT_START{                              \
  89   gint error = setpriority (PRIO_PROCESS, (pid), priority_map[prio]);   \
  90   if (error == -1 && errno == EACCES && !prio_warned)                   \
  91     {                                                                   \
  92       prio_warned = TRUE;                                               \
  93       g_warning ("Priorities can only be increased by root.");          \
  94     }                                                                   \
  95   }G_STMT_END
  96 #endif /* G_THREAD_USE_PID_SURROGATE */
  97
  98 typedef struct _GStaticPrivateNode GStaticPrivateNode;
  99 struct _GStaticPrivateNode
 100 {
 101   gpointer       data;
 102   GDestroyNotify destroy;
 103 };
 104
 105 static void g_thread_cleanup (gpointer data);
 106 static void g_thread_fail (void);
 107
 108 /* Global variables */
 109
 110 static GSystemThread zero_thread; /* This is initialized to all zero */
 111 gboolean g_thread_use_default_impl = TRUE;
 112 gboolean g_threads_got_initialized = FALSE;
 113
 114 #if defined(G_OS_WIN32) && defined(__GNUC__)
 115 __declspec(dllexport)
 116 #endif
 117 GThreadFunctions g_thread_functions_for_glib_use = {
 118   (GMutex*(*)())g_thread_fail,                 /* mutex_new */
 119   NULL,                                        /* mutex_lock */
 120   NULL,                                        /* mutex_trylock */
 121   NULL,                                        /* mutex_unlock */
 122   NULL,                                        /* mutex_free */
 123   (GCond*(*)())g_thread_fail,                  /* cond_new */
 124   NULL,                                        /* cond_signal */
 125   NULL,                                        /* cond_broadcast */
 126   NULL,                                        /* cond_wait */
 127   NULL,                                        /* cond_timed_wait  */
 128   NULL,                                        /* cond_free */
 129   (GPrivate*(*)(GDestroyNotify))g_thread_fail, /* private_new */
 130   NULL,                                        /* private_get */
 131   NULL,                                        /* private_set */
 132   (void(*)(GThreadFunc, gpointer, gulong,
 133            gboolean, gboolean, GThreadPriority,
 134            gpointer, GError**))g_thread_fail,  /* thread_create */
 135   NULL,                                        /* thread_yield */
 136   NULL,                                        /* thread_join */
 137   NULL,                                        /* thread_exit */
 138   NULL,                                        /* thread_set_priority */
 139   NULL                                         /* thread_self */
 140 };
 141
 142 /* Local data */
 143
 144 static GMutex   *g_mutex_protect_static_mutex_allocation = NULL;
 145 static GPrivate *g_thread_specific_private = NULL;
 146 static GSList   *g_thread_all_threads = NULL;
 147 static GSList   *g_thread_free_indeces = NULL;
 148
 149 G_LOCK_DEFINE_STATIC (g_thread);
 150
 151 /* This must be called only once, before any threads are created.
 152  * It will only be called from g_thread_init() in -lgthread.
 153  */
 154 void
 155 g_mutex_init (void)
 156 {
 157   GRealThread* main_thread;
 158
 159   /* We let the main thread (the one that calls g_thread_init) inherit
 160    * the data, that it set before calling g_thread_init
 161    */
 162   main_thread = (GRealThread*) g_thread_self ();
 163
 164   g_thread_specific_private = g_private_new (g_thread_cleanup);
 165   G_THREAD_UF (private_set, (g_thread_specific_private, main_thread));
 166   G_THREAD_UF (thread_self, (&main_thread->system_thread));
 167
 168   g_mutex_protect_static_mutex_allocation = g_mutex_new ();
 169 }
 170
 171 void
 172 g_static_mutex_init (GStaticMutex *mutex)
 173 {
 174   static GStaticMutex init_mutex = G_STATIC_MUTEX_INIT;
 175
 176   g_return_if_fail (mutex);
 177
 178   memcpy (mutex, &init_mutex, sizeof (GStaticMutex));
 179 }
 180
 181 GMutex *
 182 g_static_mutex_get_mutex_impl (GMutex** mutex)
 183 {
 184   if (!g_thread_supported ())
 185     return NULL;
 186
 187   g_assert (g_mutex_protect_static_mutex_allocation);
 188
 189   g_mutex_lock (g_mutex_protect_static_mutex_allocation);
 190
 191   if (!(*mutex))
 192     *mutex = g_mutex_new ();
 193
 194   g_mutex_unlock (g_mutex_protect_static_mutex_allocation);
 195
 196   return *mutex;
 197 }
 198
 199 void
 200 g_static_mutex_free (GStaticMutex* mutex)
 201 {
 202   GMutex **runtime_mutex;
 203
 204   g_return_if_fail (mutex);
 205
 206   /* The runtime_mutex is the first (or only) member of GStaticMutex,
 207    * see both versions (of glibconfig.h) in configure.in */
 208   runtime_mutex = ((GMutex**)mutex);
 209
 210   if (*runtime_mutex)
 211     g_mutex_free (*runtime_mutex);
 212
 213   *runtime_mutex = NULL;
 214 }
 215
 216 void
 217 g_static_rec_mutex_init (GStaticRecMutex *mutex)
 218 {
 219   static GStaticRecMutex init_mutex = G_STATIC_REC_MUTEX_INIT;
 220
 221   g_return_if_fail (mutex);
 222
 223   memcpy (mutex, &init_mutex, sizeof (GStaticRecMutex));
 224 }
 225
 226 void
 227 g_static_rec_mutex_lock (GStaticRecMutex* mutex)
 228 {
 229   GSystemThread self;
 230
 231   g_return_if_fail (mutex);
 232
 233   if (!g_thread_supported ())
 234     return;
 235
 236   G_THREAD_UF (thread_self, (&self));
 237
 238   if (g_system_thread_equal (self, mutex->owner))
 239     {
 240       mutex->depth++;
 241       return;
 242     }
 243   g_static_mutex_lock (&mutex->mutex);
 244   g_system_thread_assign (mutex->owner, self);
 245   mutex->depth = 1;
 246 }
 247
 248 gboolean
 249 g_static_rec_mutex_trylock (GStaticRecMutex* mutex)
 250 {
 251   GSystemThread self;
 252
 253   g_return_val_if_fail (mutex, FALSE);
 254
 255   if (!g_thread_supported ())
 256     return TRUE;
 257
 258   G_THREAD_UF (thread_self, (&self));
 259
 260   if (g_system_thread_equal (self, mutex->owner))
 261     {
 262       mutex->depth++;
 263       return TRUE;
 264     }
 265
 266   if (!g_static_mutex_trylock (&mutex->mutex))
 267     return FALSE;
 268
 269   g_system_thread_assign (mutex->owner, self);
 270   mutex->depth = 1;
 271   return TRUE;
 272 }
 273
 274 void
 275 g_static_rec_mutex_unlock (GStaticRecMutex* mutex)
 276 {
 277   g_return_if_fail (mutex);
 278
 279   if (!g_thread_supported ())
 280     return;
 281
 282   if (mutex->depth > 1)
 283     {
 284       mutex->depth--;
 285       return;
 286     }
 287   g_system_thread_assign (mutex->owner, zero_thread);
 288   g_static_mutex_unlock (&mutex->mutex);
 289 }
 290
 291 void
 292 g_static_rec_mutex_lock_full   (GStaticRecMutex *mutex,
 293                                 guint            depth)
 294 {
 295   GSystemThread self;
 296   g_return_if_fail (mutex);
 297
 298   if (!g_thread_supported ())
 299     return;
 300
 301   G_THREAD_UF (thread_self, (&self));
 302
 303   if (g_system_thread_equal (self, mutex->owner))
 304     {
 305       mutex->depth += depth;
 306       return;
 307     }
 308   g_static_mutex_lock (&mutex->mutex);
 309   g_system_thread_assign (mutex->owner, self);
 310   mutex->depth = depth;
 311 }
 312
 313 guint
 314 g_static_rec_mutex_unlock_full (GStaticRecMutex *mutex)
 315 {
 316   gint depth;
 317
 318   g_return_val_if_fail (mutex, 0);
 319
 320   if (!g_thread_supported ())
 321     return 1;
 322
 323   depth = mutex->depth;
 324
 325   g_system_thread_assign (mutex->owner, zero_thread);
 326   mutex->depth = 0;
 327   g_static_mutex_unlock (&mutex->mutex);
 328
 329   return depth;
 330 }
 331
 332 void
 333 g_static_rec_mutex_free (GStaticRecMutex *mutex)
 334 {
 335   g_return_if_fail (mutex);
 336
 337   g_static_mutex_free (&mutex->mutex);
 338 }
 339
 340 void
 341 g_static_private_init (GStaticPrivate *private_key)
 342 {
 343   private_key->index = 0;
 344 }
 345
 346 gpointer
 347 g_static_private_get (GStaticPrivate *private_key)
 348 {
 349   return g_static_private_get_for_thread (private_key, g_thread_self ());
 350 }
 351
 352 gpointer
 353 g_static_private_get_for_thread (GStaticPrivate *private_key,
 354                                  GThread        *thread)
 355 {
 356   GArray *array;
 357   GRealThread *self = (GRealThread*) thread;
 358
 359   g_return_val_if_fail (thread, NULL);
 360
 361   array = self->private_data;
 362   if (!array)
 363     return NULL;
 364
 365   if (!private_key->index)
 366     return NULL;
 367   else if (private_key->index <= array->len)
 368     return g_array_index (array, GStaticPrivateNode, private_key->index - 1).data;
 369   else
 370     return NULL;
 371 }
 372
 373 void
 374 g_static_private_set (GStaticPrivate *private_key,
 375                       gpointer        data,
 376                       GDestroyNotify  notify)
 377 {
 378   g_static_private_set_for_thread (private_key, g_thread_self (),
 379                                    data, notify);
 380 }
 381
 382 void
 383 g_static_private_set_for_thread (GStaticPrivate *private_key,
 384                                  GThread        *thread,
 385                                  gpointer        data,
 386                                  GDestroyNotify  notify)
 387 {
 388   GArray *array;
 389   GRealThread *self =(GRealThread*) thread;
 390   static guint next_index = 0;
 391   GStaticPrivateNode *node;
 392
 393   g_return_if_fail (thread);
 394
 395   array = self->private_data;
 396   if (!array)
 397     {
 398       array = g_array_new (FALSE, TRUE, sizeof (GStaticPrivateNode));
 399       self->private_data = array;
 400     }
 401
 402   if (!private_key->index)
 403     {
 404       G_LOCK (g_thread);
 405
 406       if (!private_key->index)
 407         {
 408           if (g_thread_free_indeces)
 409             {
 410               private_key->index =
 411                 GPOINTER_TO_UINT (g_thread_free_indeces->data);
 412               g_thread_free_indeces =
 413                 g_slist_delete_link (g_thread_free_indeces,
 414                                      g_thread_free_indeces);
 415             }
 416           else
 417             private_key->index = ++next_index;
 418         }
 419
 420       G_UNLOCK (g_thread);
 421     }
 422
 423   if (private_key->index > array->len)
 424     g_array_set_size (array, private_key->index);
 425
 426   node = &g_array_index (array, GStaticPrivateNode, private_key->index - 1);
 427   if (node->destroy)
 428     {
 429       gpointer ddata = node->data;
 430       GDestroyNotify ddestroy = node->destroy;
 431
 432       node->data = data;
 433       node->destroy = notify;
 434
 435       ddestroy (ddata);
 436     }
 437   else
 438     {
 439       node->data = data;
 440       node->destroy = notify;
 441     }
 442 }
 443
 444 void
 445 g_static_private_free (GStaticPrivate *private_key)
 446 {
 447   GStaticPrivate copied_key;
 448   GSList *list;
 449
 450   copied_key.index = private_key->index;
 451   private_key->index = 0;
 452
 453   if (!copied_key.index)
 454     return;
 455
 456   G_LOCK (g_thread);
 457   list =  g_thread_all_threads;
 458   while (list)
 459     {
 460       GThread *thread = list->data;
 461       list = list->next;
 462
 463       G_UNLOCK (g_thread);
 464       g_static_private_set_for_thread (&copied_key, thread, NULL, NULL);
 465       G_LOCK (g_thread);
 466     }
 467   g_thread_free_indeces =
 468     g_slist_prepend (g_thread_free_indeces,
 469                      GUINT_TO_POINTER (copied_key.index));
 470   G_UNLOCK (g_thread);
 471 }
 472
 473 static void
 474 g_thread_cleanup (gpointer data)
 475 {
 476   if (data)
 477     {
 478       GRealThread* thread = data;
 479       if (thread->private_data)
 480         {
 481           GArray* array = thread->private_data;
 482           guint i;
 483
 484           for (i = 0; i < array->len; i++ )
 485             {
 486               GStaticPrivateNode *node =
 487                 &g_array_index (array, GStaticPrivateNode, i);
 488               if (node->destroy)
 489                 node->destroy (node->data);
 490             }
 491           g_array_free (array, TRUE);
 492         }
 493       /* We only free the thread structure, if it isn't joinable. If
 494          it is, the structure is freed in g_thread_join */
 495       if (!thread->thread.joinable)
 496         {
 497           G_LOCK (g_thread);
 498           g_thread_all_threads = g_slist_remove (g_thread_all_threads, data);
 499           G_UNLOCK (g_thread);
 500
 501           /* Just to make sure, this isn't used any more */
 502           g_system_thread_assign (thread->system_thread, zero_thread);
 503           g_free (thread);
 504         }
 505     }
 506 }
 507
 508 static void
 509 g_thread_fail (void)
 510 {
 511   g_error ("The thread system is not yet initialized.");
 512 }
 513
 514 static void
 515 g_thread_create_proxy (gpointer data)
 516 {
 517   GRealThread* thread = data;
 518
 519   g_assert (data);
 520
 521 #ifdef G_THREAD_USE_PID_SURROGATE
 522   thread->pid = getpid ();
 523 #endif /* G_THREAD_USE_PID_SURROGATE */
 524
 525   /* This has to happen before G_LOCK, as that might call g_thread_self */
 526   g_private_set (g_thread_specific_private, data);
 527
 528   /* the lock makes sure, that thread->system_thread is written,
 529      before thread->func is called. See g_thread_create. */
 530   G_LOCK (g_thread);
 531   G_UNLOCK (g_thread);
 532
 533 #ifdef G_THREAD_USE_PID_SURROGATE
 534   if (g_thread_use_default_impl)
 535     SET_PRIO (thread->pid, thread->thread.priority);
 536 #endif /* G_THREAD_USE_PID_SURROGATE */
 537
 538   thread->func (thread->arg);
 539 }
 540
 541 GThread*
 542 g_thread_create (GThreadFunc             thread_func,
 543                  gpointer                arg,
 544                  gulong                  stack_size,
 545                  gboolean                joinable,
 546                  gboolean                bound,
 547                  GThreadPriority         priority,
 548                  GError                **error)
 549 {
 550   GRealThread* result = g_new (GRealThread, 1);
 551   GError *local_error = NULL;
 552   g_return_val_if_fail (thread_func, NULL);
 553   g_return_val_if_fail (priority >= G_THREAD_PRIORITY_LOW, NULL);
 554   g_return_val_if_fail (priority <= G_THREAD_PRIORITY_URGENT, NULL);
 555
 556   result->thread.joinable = joinable;
 557   result->thread.bound = bound;
 558   result->thread.priority = priority;
 559   result->func = thread_func;
 560   result->arg = arg;
 561   result->private_data = NULL;
 562   G_LOCK (g_thread);
 563   G_THREAD_UF (thread_create, (g_thread_create_proxy, result,
 564                                stack_size, joinable, bound, priority,
 565                                &result->system_thread, &local_error));
 566   g_thread_all_threads = g_slist_prepend (g_thread_all_threads, result);
 567   G_UNLOCK (g_thread);
 568
 569   if (local_error)
 570     {
 571       g_propagate_error (error, local_error);
 572       g_free (result);
 573       return NULL;
 574     }
 575
 576   return (GThread*) result;
 577 }
 578
 579 void
 580 g_thread_join (GThread* thread)
 581 {
 582   GRealThread* real = (GRealThread*) thread;
 583
 584
 585   g_return_if_fail (thread);
 586   g_return_if_fail (thread->joinable);
 587   g_return_if_fail (!g_system_thread_equal (real->system_thread, zero_thread));
 588
 589   G_THREAD_UF (thread_join, (&real->system_thread));
 590
 591   G_LOCK (g_thread);
 592   g_thread_all_threads = g_slist_remove (g_thread_all_threads, thread);
 593   G_UNLOCK (g_thread);
 594
 595   /* Just to make sure, this isn't used any more */
 596   thread->joinable = 0;
 597   g_system_thread_assign (real->system_thread, zero_thread);
 598
 599   /* the thread structure for non-joinable threads is freed upon
 600      thread end. We free the memory here. This will leave loose end,
 601      if a joinable thread is not joined. */
 602
 603   g_free (thread);
 604 }
 605
 606 void
 607 g_thread_set_priority (GThread* thread,
 608                        GThreadPriority priority)
 609 {
 610   GRealThread* real = (GRealThread*) thread;
 611
 612   g_return_if_fail (thread);
 613   g_return_if_fail (!g_system_thread_equal (real->system_thread, zero_thread));
 614   g_return_if_fail (priority >= G_THREAD_PRIORITY_LOW);
 615   g_return_if_fail (priority <= G_THREAD_PRIORITY_URGENT);
 616
 617   thread->priority = priority;
 618
 619 #ifdef G_THREAD_USE_PID_SURROGATE
 620   if (g_thread_use_default_impl)
 621     SET_PRIO (real->pid, priority);
 622   else
 623 #endif /* G_THREAD_USE_PID_SURROGATE */
 624     G_THREAD_CF (thread_set_priority, (void)0,
 625                  (&real->system_thread, priority));
 626 }
 627
 628 GThread*
 629 g_thread_self (void)
 630 {
 631   GRealThread* thread = g_private_get (g_thread_specific_private);
 632
 633   if (!thread)
 634     {
 635       /* If no thread data is available, provide and set one.  This
 636          can happen for the main thread and for threads, that are not
 637          created by GLib. */
 638       thread = g_new (GRealThread, 1);
 639       thread->thread.joinable = FALSE; /* This is a save guess */
 640       thread->thread.bound = TRUE; /* This isn't important at all */
 641       thread->thread.priority = G_THREAD_PRIORITY_NORMAL; /* This is
 642                                                              just a guess */
 643       thread->func = NULL;
 644       thread->arg = NULL;
 645       thread->private_data = NULL;
 646
 647       if (g_thread_supported ())
 648         G_THREAD_UF (thread_self, (&thread->system_thread));
 649
 650 #ifdef G_THREAD_USE_PID_SURROGATE
 651       thread->pid = getpid ();
 652 #endif /* G_THREAD_USE_PID_SURROGATE */
 653
 654       g_private_set (g_thread_specific_private, thread);
 655
 656       G_LOCK (g_thread);
 657       g_thread_all_threads = g_slist_prepend (g_thread_all_threads, thread);
 658       G_UNLOCK (g_thread);
 659     }
 660
 661   return (GThread*)thread;
 662 }
 663
 664 void
 665 g_static_rw_lock_init (GStaticRWLock* lock)
 666 {
 667   static GStaticRWLock init_lock = G_STATIC_RW_LOCK_INIT;
 668
 669   g_return_if_fail (lock);
 670
 671   memcpy (lock, &init_lock, sizeof (GStaticRWLock));
 672 }
 673
 674 static void inline
 675 g_static_rw_lock_wait (GCond** cond, GStaticMutex* mutex)
 676 {
 677   if (!*cond)
 678       *cond = g_cond_new ();
 679   g_cond_wait (*cond, g_static_mutex_get_mutex (mutex));
 680 }
 681
 682 static void inline
 683 g_static_rw_lock_signal (GStaticRWLock* lock)
 684 {
 685   if (lock->want_to_write && lock->write_cond)
 686     g_cond_signal (lock->write_cond);
 687   else if (lock->read_cond)
 688     g_cond_broadcast (lock->read_cond);
 689 }
 690
 691 void
 692 g_static_rw_lock_reader_lock (GStaticRWLock* lock)
 693 {
 694   g_return_if_fail (lock);
 695
 696   if (!g_threads_got_initialized)
 697     return;
 698
 699   g_static_mutex_lock (&lock->mutex);
 700   while (lock->write || lock->want_to_write)
 701     g_static_rw_lock_wait (&lock->read_cond, &lock->mutex);
 702   lock->read_counter++;
 703   g_static_mutex_unlock (&lock->mutex);
 704 }
 705
 706 gboolean
 707 g_static_rw_lock_reader_trylock (GStaticRWLock* lock)
 708 {
 709   gboolean ret_val = FALSE;
 710
 711   g_return_val_if_fail (lock, FALSE);
 712
 713   if (!g_threads_got_initialized)
 714     return TRUE;
 715
 716   g_static_mutex_lock (&lock->mutex);
 717   if (!lock->write && !lock->want_to_write)
 718     {
 719       lock->read_counter++;
 720       ret_val = TRUE;
 721     }
 722   g_static_mutex_unlock (&lock->mutex);
 723   return ret_val;
 724 }
 725
 726 void
 727 g_static_rw_lock_reader_unlock  (GStaticRWLock* lock)
 728 {
 729   g_return_if_fail (lock);
 730
 731   if (!g_threads_got_initialized)
 732     return;
 733
 734   g_static_mutex_lock (&lock->mutex);
 735   lock->read_counter--;
 736   if (lock->read_counter == 0)
 737     g_static_rw_lock_signal (lock);
 738   g_static_mutex_unlock (&lock->mutex);
 739 }
 740
 741 void
 742 g_static_rw_lock_writer_lock (GStaticRWLock* lock)
 743 {
 744   g_return_if_fail (lock);
 745
 746   if (!g_threads_got_initialized)
 747     return;
 748
 749   g_static_mutex_lock (&lock->mutex);
 750   lock->want_to_write++;
 751   while (lock->write || lock->read_counter)
 752     g_static_rw_lock_wait (&lock->write_cond, &lock->mutex);
 753   lock->want_to_write--;
 754   lock->write = TRUE;
 755   g_static_mutex_unlock (&lock->mutex);
 756 }
 757
 758 gboolean
 759 g_static_rw_lock_writer_trylock (GStaticRWLock* lock)
 760 {
 761   gboolean ret_val = FALSE;
 762
 763   g_return_val_if_fail (lock, FALSE);
 764
 765   if (!g_threads_got_initialized)
 766     return TRUE;
 767
 768   g_static_mutex_lock (&lock->mutex);
 769   if (!lock->write && !lock->read_counter)
 770     {
 771       lock->write = TRUE;
 772       ret_val = TRUE;
 773     }
 774   g_static_mutex_unlock (&lock->mutex);
 775   return ret_val;
 776 }
 777
 778 void
 779 g_static_rw_lock_writer_unlock (GStaticRWLock* lock)
 780 {
 781   g_return_if_fail (lock);
 782
 783   if (!g_threads_got_initialized)
 784     return;
 785
 786   g_static_mutex_lock (&lock->mutex);
 787   lock->write = FALSE;
 788   g_static_rw_lock_signal (lock);
 789   g_static_mutex_unlock (&lock->mutex);
 790 }
 791
 792 void
 793 g_static_rw_lock_free (GStaticRWLock* lock)
 794 {
 795   g_return_if_fail (lock);
 796
 797   if (lock->read_cond)
 798     {
 799       g_cond_free (lock->read_cond);
 800       lock->read_cond = NULL;
 801     }
 802   if (lock->write_cond)
 803     {
 804       g_cond_free (lock->write_cond);
 805       lock->write_cond = NULL;
 806     }
 807   g_static_mutex_free (&lock->mutex);
 808 }