glib/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 /* Keep this in sync with GRealThread in gmain.c! */
  73 typedef struct _GRealThread GRealThread;
  74 struct  _GRealThread
  75 {
  76   GThread thread;
  77   gpointer private_data;
  78   gpointer retval;
  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_PLATFORM_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   *mutex = init_mutex;
 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   *mutex = init_mutex;
 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   GRealThread *self = (GRealThread*) g_thread_self ();
 350   GArray *array;
 351
 352   array = self->private_data;
 353   if (!array)
 354     return NULL;
 355
 356   if (!private_key->index)
 357     return NULL;
 358   else if (private_key->index <= array->len)
 359     return g_array_index (array, GStaticPrivateNode,
 360                           private_key->index - 1).data;
 361   else
 362     return NULL;
 363 }
 364
 365 void
 366 g_static_private_set (GStaticPrivate *private_key,
 367                       gpointer        data,
 368                       GDestroyNotify  notify)
 369 {
 370   GRealThread *self = (GRealThread*) g_thread_self ();
 371   GArray *array;
 372   static guint next_index = 0;
 373   GStaticPrivateNode *node;
 374
 375   array = self->private_data;
 376   if (!array)
 377     {
 378       array = g_array_new (FALSE, TRUE, sizeof (GStaticPrivateNode));
 379       self->private_data = array;
 380     }
 381
 382   if (!private_key->index)
 383     {
 384       G_LOCK (g_thread);
 385
 386       if (!private_key->index)
 387         {
 388           if (g_thread_free_indeces)
 389             {
 390               private_key->index =
 391                 GPOINTER_TO_UINT (g_thread_free_indeces->data);
 392               g_thread_free_indeces =
 393                 g_slist_delete_link (g_thread_free_indeces,
 394                                      g_thread_free_indeces);
 395             }
 396           else
 397             private_key->index = ++next_index;
 398         }
 399
 400       G_UNLOCK (g_thread);
 401     }
 402
 403   if (private_key->index > array->len)
 404     g_array_set_size (array, private_key->index);
 405
 406   node = &g_array_index (array, GStaticPrivateNode, private_key->index - 1);
 407   if (node->destroy)
 408     {
 409       gpointer ddata = node->data;
 410       GDestroyNotify ddestroy = node->destroy;
 411
 412       node->data = data;
 413       node->destroy = notify;
 414
 415       ddestroy (ddata);
 416     }
 417   else
 418     {
 419       node->data = data;
 420       node->destroy = notify;
 421     }
 422 }
 423
 424 void
 425 g_static_private_free (GStaticPrivate *private_key)
 426 {
 427   guint index = private_key->index;
 428   GSList *list;
 429
 430   if (!index)
 431     return;
 432
 433   private_key->index = 0;
 434
 435   G_LOCK (g_thread);
 436   list =  g_thread_all_threads;
 437   while (list)
 438     {
 439       GRealThread *thread = list->data;
 440       GArray *array = thread->private_data;
 441       list = list->next;
 442
 443       if (array && index <= array->len)
 444         {
 445           GStaticPrivateNode *node = &g_array_index (array,
 446                                                      GStaticPrivateNode,
 447                                                      index - 1);
 448           gpointer ddata = node->data;
 449           GDestroyNotify ddestroy = node->destroy;
 450
 451           node->data = NULL;
 452           node->destroy = NULL;
 453
 454           if (ddestroy)
 455             {
 456               G_UNLOCK (g_thread);
 457               ddestroy (ddata);
 458               G_LOCK (g_thread);
 459               }
 460         }
 461     }
 462   g_thread_free_indeces = g_slist_prepend (g_thread_free_indeces,
 463                                            GUINT_TO_POINTER (index));
 464   G_UNLOCK (g_thread);
 465 }
 466
 467 static void
 468 g_thread_cleanup (gpointer data)
 469 {
 470   if (data)
 471     {
 472       GRealThread* thread = data;
 473       if (thread->private_data)
 474         {
 475           GArray* array = thread->private_data;
 476           guint i;
 477
 478           for (i = 0; i < array->len; i++ )
 479             {
 480               GStaticPrivateNode *node =
 481                 &g_array_index (array, GStaticPrivateNode, i);
 482               if (node->destroy)
 483                 node->destroy (node->data);
 484             }
 485           g_array_free (array, TRUE);
 486         }
 487
 488       /* We only free the thread structure, if it isn't joinable. If
 489          it is, the structure is freed in g_thread_join */
 490       if (!thread->thread.joinable)
 491         {
 492           G_LOCK (g_thread);
 493           g_thread_all_threads = g_slist_remove (g_thread_all_threads, data);
 494           G_UNLOCK (g_thread);
 495
 496           /* Just to make sure, this isn't used any more */
 497           g_system_thread_assign (thread->system_thread, zero_thread);
 498           g_free (thread);
 499         }
 500     }
 501 }
 502
 503 static void
 504 g_thread_fail (void)
 505 {
 506   g_error ("The thread system is not yet initialized.");
 507 }
 508
 509 static gpointer
 510 g_thread_create_proxy (gpointer data)
 511 {
 512   GRealThread* thread = data;
 513
 514   g_assert (data);
 515
 516 #ifdef G_THREAD_USE_PID_SURROGATE
 517   thread->pid = getpid ();
 518 #endif /* G_THREAD_USE_PID_SURROGATE */
 519
 520   /* This has to happen before G_LOCK, as that might call g_thread_self */
 521   g_private_set (g_thread_specific_private, data);
 522
 523   /* the lock makes sure, that thread->system_thread is written,
 524      before thread->thread.func is called. See g_thread_create. */
 525   G_LOCK (g_thread);
 526   G_UNLOCK (g_thread);
 527
 528 #ifdef G_THREAD_USE_PID_SURROGATE
 529   if (g_thread_use_default_impl)
 530     SET_PRIO (thread->pid, thread->thread.priority);
 531 #endif /* G_THREAD_USE_PID_SURROGATE */
 532
 533   thread->retval = thread->thread.func (thread->thread.data);
 534
 535   return NULL;
 536 }
 537
 538 GThread*
 539 g_thread_create_full (GThreadFunc                func,
 540                       gpointer           data,
 541                       gulong             stack_size,
 542                       gboolean           joinable,
 543                       gboolean           bound,
 544                       GThreadPriority    priority,
 545                       GError                **error)
 546 {
 547   GRealThread* result = g_new (GRealThread, 1);
 548   GError *local_error = NULL;
 549   g_return_val_if_fail (func, NULL);
 550   g_return_val_if_fail (priority >= G_THREAD_PRIORITY_LOW, NULL);
 551   g_return_val_if_fail (priority <= G_THREAD_PRIORITY_URGENT, NULL);
 552
 553   result->thread.joinable = joinable;
 554   result->thread.priority = priority;
 555   result->thread.func = func;
 556   result->thread.data = data;
 557   result->private_data = NULL;
 558   G_LOCK (g_thread);
 559   G_THREAD_UF (thread_create, (g_thread_create_proxy, result,
 560                                stack_size, joinable, bound, priority,
 561                                &result->system_thread, &local_error));
 562   g_thread_all_threads = g_slist_prepend (g_thread_all_threads, result);
 563   G_UNLOCK (g_thread);
 564
 565   if (local_error)
 566     {
 567       g_propagate_error (error, local_error);
 568       g_free (result);
 569       return NULL;
 570     }
 571
 572   return (GThread*) result;
 573 }
 574
 575 void
 576 g_thread_exit (gpointer retval)
 577 {
 578   GRealThread* real = (GRealThread*) g_thread_self ();
 579   real->retval = retval;
 580   G_THREAD_CF (thread_exit, (void)0, ());
 581 }
 582
 583 gpointer
 584 g_thread_join (GThread* thread)
 585 {
 586   GRealThread* real = (GRealThread*) thread;
 587   gpointer retval;
 588
 589   g_return_val_if_fail (thread, NULL);
 590   g_return_val_if_fail (thread->joinable, NULL);
 591   g_return_val_if_fail (!g_system_thread_equal (real->system_thread,
 592                                                 zero_thread), NULL);
 593
 594   G_THREAD_UF (thread_join, (&real->system_thread));
 595
 596   retval = real->retval;
 597
 598   G_LOCK (g_thread);
 599   g_thread_all_threads = g_slist_remove (g_thread_all_threads, thread);
 600   G_UNLOCK (g_thread);
 601
 602   /* Just to make sure, this isn't used any more */
 603   thread->joinable = 0;
 604   g_system_thread_assign (real->system_thread, zero_thread);
 605
 606   /* the thread structure for non-joinable threads is freed upon
 607      thread end. We free the memory here. This will leave a loose end,
 608      if a joinable thread is not joined. */
 609
 610   g_free (thread);
 611
 612   return retval;
 613 }
 614
 615 void
 616 g_thread_set_priority (GThread* thread,
 617                        GThreadPriority priority)
 618 {
 619   GRealThread* real = (GRealThread*) thread;
 620
 621   g_return_if_fail (thread);
 622   g_return_if_fail (!g_system_thread_equal (real->system_thread, zero_thread));
 623   g_return_if_fail (priority >= G_THREAD_PRIORITY_LOW);
 624   g_return_if_fail (priority <= G_THREAD_PRIORITY_URGENT);
 625
 626   thread->priority = priority;
 627
 628 #ifdef G_THREAD_USE_PID_SURROGATE
 629   if (g_thread_use_default_impl)
 630     SET_PRIO (real->pid, priority);
 631   else
 632 #endif /* G_THREAD_USE_PID_SURROGATE */
 633     G_THREAD_CF (thread_set_priority, (void)0,
 634                  (&real->system_thread, priority));
 635 }
 636
 637 GThread*
 638 g_thread_self (void)
 639 {
 640   GRealThread* thread = g_private_get (g_thread_specific_private);
 641
 642   if (!thread)
 643     {
 644       /* If no thread data is available, provide and set one.  This
 645          can happen for the main thread and for threads, that are not
 646          created by GLib. */
 647       thread = g_new (GRealThread, 1);
 648       thread->thread.joinable = FALSE; /* This is a save guess */
 649       thread->thread.priority = G_THREAD_PRIORITY_NORMAL; /* This is
 650                                                              just a guess */
 651       thread->thread.func = NULL;
 652       thread->thread.data = NULL;
 653       thread->private_data = NULL;
 654
 655       if (g_thread_supported ())
 656         G_THREAD_UF (thread_self, (&thread->system_thread));
 657
 658 #ifdef G_THREAD_USE_PID_SURROGATE
 659       thread->pid = getpid ();
 660 #endif /* G_THREAD_USE_PID_SURROGATE */
 661
 662       g_private_set (g_thread_specific_private, thread);
 663
 664       G_LOCK (g_thread);
 665       g_thread_all_threads = g_slist_prepend (g_thread_all_threads, thread);
 666       G_UNLOCK (g_thread);
 667     }
 668
 669   return (GThread*)thread;
 670 }
 671
 672 void
 673 g_static_rw_lock_init (GStaticRWLock* lock)
 674 {
 675   static GStaticRWLock init_lock = G_STATIC_RW_LOCK_INIT;
 676
 677   g_return_if_fail (lock);
 678
 679   *lock = init_lock;
 680 }
 681
 682 static void inline
 683 g_static_rw_lock_wait (GCond** cond, GStaticMutex* mutex)
 684 {
 685   if (!*cond)
 686       *cond = g_cond_new ();
 687   g_cond_wait (*cond, g_static_mutex_get_mutex (mutex));
 688 }
 689
 690 static void inline
 691 g_static_rw_lock_signal (GStaticRWLock* lock)
 692 {
 693   if (lock->want_to_write && lock->write_cond)
 694     g_cond_signal (lock->write_cond);
 695   else if (lock->want_to_read && lock->read_cond)
 696     g_cond_broadcast (lock->read_cond);
 697 }
 698
 699 void
 700 g_static_rw_lock_reader_lock (GStaticRWLock* lock)
 701 {
 702   g_return_if_fail (lock);
 703
 704   if (!g_threads_got_initialized)
 705     return;
 706
 707   g_static_mutex_lock (&lock->mutex);
 708   lock->want_to_read++;
 709   while (lock->write || lock->want_to_write)
 710     g_static_rw_lock_wait (&lock->read_cond, &lock->mutex);
 711   lock->want_to_read--;
 712   lock->read_counter++;
 713   g_static_mutex_unlock (&lock->mutex);
 714 }
 715
 716 gboolean
 717 g_static_rw_lock_reader_trylock (GStaticRWLock* lock)
 718 {
 719   gboolean ret_val = FALSE;
 720
 721   g_return_val_if_fail (lock, FALSE);
 722
 723   if (!g_threads_got_initialized)
 724     return TRUE;
 725
 726   g_static_mutex_lock (&lock->mutex);
 727   if (!lock->write && !lock->want_to_write)
 728     {
 729       lock->read_counter++;
 730       ret_val = TRUE;
 731     }
 732   g_static_mutex_unlock (&lock->mutex);
 733   return ret_val;
 734 }
 735
 736 void
 737 g_static_rw_lock_reader_unlock  (GStaticRWLock* lock)
 738 {
 739   g_return_if_fail (lock);
 740
 741   if (!g_threads_got_initialized)
 742     return;
 743
 744   g_static_mutex_lock (&lock->mutex);
 745   lock->read_counter--;
 746   if (lock->read_counter == 0)
 747     g_static_rw_lock_signal (lock);
 748   g_static_mutex_unlock (&lock->mutex);
 749 }
 750
 751 void
 752 g_static_rw_lock_writer_lock (GStaticRWLock* lock)
 753 {
 754   g_return_if_fail (lock);
 755
 756   if (!g_threads_got_initialized)
 757     return;
 758
 759   g_static_mutex_lock (&lock->mutex);
 760   lock->want_to_write++;
 761   while (lock->write || lock->read_counter)
 762     g_static_rw_lock_wait (&lock->write_cond, &lock->mutex);
 763   lock->want_to_write--;
 764   lock->write = TRUE;
 765   g_static_mutex_unlock (&lock->mutex);
 766 }
 767
 768 gboolean
 769 g_static_rw_lock_writer_trylock (GStaticRWLock* lock)
 770 {
 771   gboolean ret_val = FALSE;
 772
 773   g_return_val_if_fail (lock, FALSE);
 774
 775   if (!g_threads_got_initialized)
 776     return TRUE;
 777
 778   g_static_mutex_lock (&lock->mutex);
 779   if (!lock->write && !lock->read_counter)
 780     {
 781       lock->write = TRUE;
 782       ret_val = TRUE;
 783     }
 784   g_static_mutex_unlock (&lock->mutex);
 785   return ret_val;
 786 }
 787
 788 void
 789 g_static_rw_lock_writer_unlock (GStaticRWLock* lock)
 790 {
 791   g_return_if_fail (lock);
 792
 793   if (!g_threads_got_initialized)
 794     return;
 795
 796   g_static_mutex_lock (&lock->mutex);
 797   lock->write = FALSE;
 798   g_static_rw_lock_signal (lock);
 799   g_static_mutex_unlock (&lock->mutex);
 800 }
 801
 802 void
 803 g_static_rw_lock_free (GStaticRWLock* lock)
 804 {
 805   g_return_if_fail (lock);
 806
 807   if (lock->read_cond)
 808     {
 809       g_cond_free (lock->read_cond);
 810       lock->read_cond = NULL;
 811     }
 812   if (lock->write_cond)
 813     {
 814       g_cond_free (lock->write_cond);
 815       lock->write_cond = NULL;
 816     }
 817   g_static_mutex_free (&lock->mutex);
 818 }