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  * gthread.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
  37 #ifdef HAVE_UNISTD_H
  38 #include <unistd.h>
  39 #endif
  40
  41 #include <string.h>
  42
  43 #include "glib.h"
  44 #include "gthreadinit.h"
  45 #include "galias.h"
  46
  47 #if GLIB_SIZEOF_SYSTEM_THREAD == SIZEOF_VOID_P
  48 # define g_system_thread_equal_simple(thread1, thread2)                 \
  49    ((thread1).dummy_pointer == (thread2).dummy_pointer)
  50 # define g_system_thread_assign(dest, src)                              \
  51    ((dest).dummy_pointer = (src).dummy_pointer)
  52 #else /* GLIB_SIZEOF_SYSTEM_THREAD != SIZEOF_VOID_P */
  53 # define g_system_thread_equal_simple(thread1, thread2)                 \
  54    (memcmp (&(thread1), &(thread2), GLIB_SIZEOF_SYSTEM_THREAD) == 0)
  55 # define g_system_thread_assign(dest, src)                              \
  56    (memcpy (&(dest), &(src), GLIB_SIZEOF_SYSTEM_THREAD))
  57 #endif /* GLIB_SIZEOF_SYSTEM_THREAD == SIZEOF_VOID_P */
  58
  59 #define g_system_thread_equal(thread1, thread2)                         \
  60   (g_thread_functions_for_glib_use.thread_equal ?                       \
  61    g_thread_functions_for_glib_use.thread_equal (&(thread1), &(thread2)) :\
  62    g_system_thread_equal_simple((thread1), (thread2)))
  63
  64 GQuark
  65 g_thread_error_quark (void)
  66 {
  67   static GQuark quark;
  68   if (!quark)
  69     quark = g_quark_from_static_string ("g_thread_error");
  70   return quark;
  71 }
  72
  73 /* Keep this in sync with GRealThread in gmain.c! */
  74 typedef struct _GRealThread GRealThread;
  75 struct  _GRealThread
  76 {
  77   GThread thread;
  78   gpointer private_data;
  79   gpointer mem_private;
  80   GRealThread *next;
  81   gpointer retval;
  82   GSystemThread system_thread;
  83 };
  84
  85 typedef struct _GStaticPrivateNode GStaticPrivateNode;
  86 struct _GStaticPrivateNode
  87 {
  88   gpointer       data;
  89   GDestroyNotify destroy;
  90 };
  91
  92 static void g_thread_cleanup (gpointer data);
  93 static void g_thread_fail (void);
  94
  95 /* Global variables */
  96
  97 static GSystemThread zero_thread; /* This is initialized to all zero */
  98 gboolean g_thread_use_default_impl = TRUE;
  99 gboolean g_threads_got_initialized = FALSE;
 100
 101 GThreadFunctions g_thread_functions_for_glib_use = {
 102   (GMutex*(*)())g_thread_fail,                 /* mutex_new */
 103   NULL,                                        /* mutex_lock */
 104   NULL,                                        /* mutex_trylock */
 105   NULL,                                        /* mutex_unlock */
 106   NULL,                                        /* mutex_free */
 107   (GCond*(*)())g_thread_fail,                  /* cond_new */
 108   NULL,                                        /* cond_signal */
 109   NULL,                                        /* cond_broadcast */
 110   NULL,                                        /* cond_wait */
 111   NULL,                                        /* cond_timed_wait  */
 112   NULL,                                        /* cond_free */
 113   (GPrivate*(*)(GDestroyNotify))g_thread_fail, /* private_new */
 114   NULL,                                        /* private_get */
 115   NULL,                                        /* private_set */
 116   (void(*)(GThreadFunc, gpointer, gulong,
 117            gboolean, gboolean, GThreadPriority,
 118            gpointer, GError**))g_thread_fail,  /* thread_create */
 119   NULL,                                        /* thread_yield */
 120   NULL,                                        /* thread_join */
 121   NULL,                                        /* thread_exit */
 122   NULL,                                        /* thread_set_priority */
 123   NULL                                         /* thread_self */
 124 };
 125
 126 /* Local data */
 127
 128 static GMutex   *g_once_mutex = NULL;
 129 static GCond    *g_once_cond = NULL;
 130 static GPrivate *g_thread_specific_private = NULL;
 131 static GRealThread *g_thread_all_threads = NULL;
 132 static GSList   *g_thread_free_indeces = NULL;
 133
 134 G_LOCK_DEFINE_STATIC (g_thread);
 135
 136 #ifdef G_THREADS_ENABLED
 137 /* This must be called only once, before any threads are created.
 138  * It will only be called from g_thread_init() in -lgthread.
 139  */
 140 void
 141 g_thread_init_glib (void)
 142 {
 143   /* We let the main thread (the one that calls g_thread_init) inherit
 144    * the static_private data set before calling g_thread_init
 145    */
 146   GRealThread* main_thread = (GRealThread*) g_thread_self ();
 147
 148   g_once_mutex = g_mutex_new ();
 149   g_once_cond = g_cond_new ();
 150
 151   _g_convert_thread_init ();
 152   _g_rand_thread_init ();
 153   _g_main_thread_init ();
 154   _g_mem_thread_init ();
 155   _g_messages_thread_init ();
 156   _g_atomic_thread_init ();
 157   _g_utils_thread_init ();
 158 #ifdef G_OS_WIN32
 159   _g_win32_thread_init ();
 160 #endif
 161
 162   g_threads_got_initialized = TRUE;
 163
 164   g_thread_specific_private = g_private_new (g_thread_cleanup);
 165   g_private_set (g_thread_specific_private, main_thread);
 166   G_THREAD_UF (thread_self, (&main_thread->system_thread));
 167
 168   _g_mem_thread_private_init ();
 169   _g_messages_thread_private_init ();
 170
 171 }
 172 #endif /* G_THREADS_ENABLED */
 173
 174 gpointer
 175 g_once_impl (GOnce       *once,
 176              GThreadFunc  func,
 177              gpointer     arg)
 178 {
 179   g_mutex_lock (g_once_mutex);
 180
 181   while (once->status == G_ONCE_STATUS_PROGRESS)
 182     g_cond_wait (g_once_cond, g_once_mutex);
 183
 184   if (once->status != G_ONCE_STATUS_READY)
 185     {
 186       once->status = G_ONCE_STATUS_PROGRESS;
 187       g_mutex_unlock (g_once_mutex);
 188
 189       once->retval = func (arg);
 190
 191       g_mutex_lock (g_once_mutex);
 192       once->status = G_ONCE_STATUS_READY;
 193       g_cond_broadcast (g_once_cond);
 194     }
 195
 196   g_mutex_unlock (g_once_mutex);
 197
 198   return once->retval;
 199 }
 200
 201 void
 202 g_static_mutex_init (GStaticMutex *mutex)
 203 {
 204   static const GStaticMutex init_mutex = G_STATIC_MUTEX_INIT;
 205
 206   g_return_if_fail (mutex);
 207
 208   *mutex = init_mutex;
 209 }
 210
 211 GMutex *
 212 g_static_mutex_get_mutex_impl (GMutex** mutex)
 213 {
 214   if (!g_thread_supported ())
 215     return NULL;
 216
 217   g_assert (g_once_mutex);
 218
 219   g_mutex_lock (g_once_mutex);
 220
 221   if (!(*mutex))
 222     {
 223       GMutex *new_mutex = g_mutex_new ();
 224
 225       /* The following is a memory barrier to avoid the write
 226        * to *new_mutex being reordered to after writing *mutex */
 227       g_mutex_lock (new_mutex);
 228       g_mutex_unlock (new_mutex);
 229
 230       *mutex = new_mutex;
 231     }
 232
 233   g_mutex_unlock (g_once_mutex);
 234
 235   return *mutex;
 236 }
 237
 238 void
 239 g_static_mutex_free (GStaticMutex* mutex)
 240 {
 241   GMutex **runtime_mutex;
 242
 243   g_return_if_fail (mutex);
 244
 245   /* The runtime_mutex is the first (or only) member of GStaticMutex,
 246    * see both versions (of glibconfig.h) in configure.in */
 247   runtime_mutex = ((GMutex**)mutex);
 248
 249   if (*runtime_mutex)
 250     g_mutex_free (*runtime_mutex);
 251
 252   *runtime_mutex = NULL;
 253 }
 254
 255 void
 256 g_static_rec_mutex_init (GStaticRecMutex *mutex)
 257 {
 258   static const GStaticRecMutex init_mutex = G_STATIC_REC_MUTEX_INIT;
 259
 260   g_return_if_fail (mutex);
 261
 262   *mutex = init_mutex;
 263 }
 264
 265 void
 266 g_static_rec_mutex_lock (GStaticRecMutex* mutex)
 267 {
 268   GSystemThread self;
 269
 270   g_return_if_fail (mutex);
 271
 272   if (!g_thread_supported ())
 273     return;
 274
 275   G_THREAD_UF (thread_self, (&self));
 276
 277   if (g_system_thread_equal (self, mutex->owner))
 278     {
 279       mutex->depth++;
 280       return;
 281     }
 282   g_static_mutex_lock (&mutex->mutex);
 283   g_system_thread_assign (mutex->owner, self);
 284   mutex->depth = 1;
 285 }
 286
 287 gboolean
 288 g_static_rec_mutex_trylock (GStaticRecMutex* mutex)
 289 {
 290   GSystemThread self;
 291
 292   g_return_val_if_fail (mutex, FALSE);
 293
 294   if (!g_thread_supported ())
 295     return TRUE;
 296
 297   G_THREAD_UF (thread_self, (&self));
 298
 299   if (g_system_thread_equal (self, mutex->owner))
 300     {
 301       mutex->depth++;
 302       return TRUE;
 303     }
 304
 305   if (!g_static_mutex_trylock (&mutex->mutex))
 306     return FALSE;
 307
 308   g_system_thread_assign (mutex->owner, self);
 309   mutex->depth = 1;
 310   return TRUE;
 311 }
 312
 313 void
 314 g_static_rec_mutex_unlock (GStaticRecMutex* mutex)
 315 {
 316   g_return_if_fail (mutex);
 317
 318   if (!g_thread_supported ())
 319     return;
 320
 321   if (mutex->depth > 1)
 322     {
 323       mutex->depth--;
 324       return;
 325     }
 326   g_system_thread_assign (mutex->owner, zero_thread);
 327   g_static_mutex_unlock (&mutex->mutex);
 328 }
 329
 330 void
 331 g_static_rec_mutex_lock_full   (GStaticRecMutex *mutex,
 332                                 guint            depth)
 333 {
 334   GSystemThread self;
 335   g_return_if_fail (mutex);
 336
 337   if (!g_thread_supported ())
 338     return;
 339
 340   if (depth == 0)
 341     return;
 342
 343   G_THREAD_UF (thread_self, (&self));
 344
 345   if (g_system_thread_equal (self, mutex->owner))
 346     {
 347       mutex->depth += depth;
 348       return;
 349     }
 350   g_static_mutex_lock (&mutex->mutex);
 351   g_system_thread_assign (mutex->owner, self);
 352   mutex->depth = depth;
 353 }
 354
 355 guint
 356 g_static_rec_mutex_unlock_full (GStaticRecMutex *mutex)
 357 {
 358   guint depth;
 359
 360   g_return_val_if_fail (mutex, 0);
 361
 362   if (!g_thread_supported ())
 363     return 1;
 364
 365   depth = mutex->depth;
 366
 367   g_system_thread_assign (mutex->owner, zero_thread);
 368   mutex->depth = 0;
 369   g_static_mutex_unlock (&mutex->mutex);
 370
 371   return depth;
 372 }
 373
 374 void
 375 g_static_rec_mutex_free (GStaticRecMutex *mutex)
 376 {
 377   g_return_if_fail (mutex);
 378
 379   g_static_mutex_free (&mutex->mutex);
 380 }
 381
 382 void
 383 g_static_private_init (GStaticPrivate *private_key)
 384 {
 385   private_key->index = 0;
 386 }
 387
 388 gpointer
 389 g_static_private_get (GStaticPrivate *private_key)
 390 {
 391   GRealThread *self = (GRealThread*) g_thread_self ();
 392   GArray *array;
 393
 394   array = self->private_data;
 395   if (!array)
 396     return NULL;
 397
 398   if (!private_key->index)
 399     return NULL;
 400   else if (private_key->index <= array->len)
 401     return g_array_index (array, GStaticPrivateNode,
 402                           private_key->index - 1).data;
 403   else
 404     return NULL;
 405 }
 406
 407 void
 408 g_static_private_set (GStaticPrivate *private_key,
 409                       gpointer        data,
 410                       GDestroyNotify  notify)
 411 {
 412   GRealThread *self = (GRealThread*) g_thread_self ();
 413   GArray *array;
 414   static guint next_index = 0;
 415   GStaticPrivateNode *node;
 416
 417   array = self->private_data;
 418   if (!array)
 419     {
 420       array = g_array_new (FALSE, TRUE, sizeof (GStaticPrivateNode));
 421       self->private_data = array;
 422     }
 423
 424   if (!private_key->index)
 425     {
 426       G_LOCK (g_thread);
 427
 428       if (!private_key->index)
 429         {
 430           if (g_thread_free_indeces)
 431             {
 432               private_key->index =
 433                 GPOINTER_TO_UINT (g_thread_free_indeces->data);
 434               g_thread_free_indeces =
 435                 g_slist_delete_link (g_thread_free_indeces,
 436                                      g_thread_free_indeces);
 437             }
 438           else
 439             private_key->index = ++next_index;
 440         }
 441
 442       G_UNLOCK (g_thread);
 443     }
 444
 445   if (private_key->index > array->len)
 446     g_array_set_size (array, private_key->index);
 447
 448   node = &g_array_index (array, GStaticPrivateNode, private_key->index - 1);
 449   if (node->destroy)
 450     {
 451       gpointer ddata = node->data;
 452       GDestroyNotify ddestroy = node->destroy;
 453
 454       node->data = data;
 455       node->destroy = notify;
 456
 457       ddestroy (ddata);
 458     }
 459   else
 460     {
 461       node->data = data;
 462       node->destroy = notify;
 463     }
 464 }
 465
 466 void
 467 g_static_private_free (GStaticPrivate *private_key)
 468 {
 469   guint index = private_key->index;
 470   GRealThread *thread;
 471
 472   if (!index)
 473     return;
 474
 475   private_key->index = 0;
 476
 477   G_LOCK (g_thread);
 478
 479   thread = g_thread_all_threads;
 480   while (thread)
 481     {
 482       GArray *array = thread->private_data;
 483       thread = thread->next;
 484
 485       if (array && index <= array->len)
 486         {
 487           GStaticPrivateNode *node = &g_array_index (array,
 488                                                      GStaticPrivateNode,
 489                                                      index - 1);
 490           gpointer ddata = node->data;
 491           GDestroyNotify ddestroy = node->destroy;
 492
 493           node->data = NULL;
 494           node->destroy = NULL;
 495
 496           if (ddestroy)
 497             {
 498               G_UNLOCK (g_thread);
 499               ddestroy (ddata);
 500               G_LOCK (g_thread);
 501               }
 502         }
 503     }
 504   g_thread_free_indeces = g_slist_prepend (g_thread_free_indeces,
 505                                            GUINT_TO_POINTER (index));
 506   G_UNLOCK (g_thread);
 507 }
 508
 509 static void
 510 g_thread_cleanup (gpointer data)
 511 {
 512   if (data)
 513     {
 514       GRealThread* thread = data;
 515       if (thread->private_data)
 516         {
 517           GArray* array = thread->private_data;
 518           guint i;
 519
 520           for (i = 0; i < array->len; i++ )
 521             {
 522               GStaticPrivateNode *node =
 523                 &g_array_index (array, GStaticPrivateNode, i);
 524               if (node->destroy)
 525                 node->destroy (node->data);
 526             }
 527           g_array_free (array, TRUE);
 528         }
 529
 530       /* We only free the thread structure, if it isn't joinable. If
 531          it is, the structure is freed in g_thread_join */
 532       if (!thread->thread.joinable)
 533         {
 534           GRealThread *t, *p;
 535
 536           G_LOCK (g_thread);
 537           for (t = g_thread_all_threads, p = NULL; t; p = t, t = t->next)
 538             {
 539               if (t == thread)
 540                 {
 541                   if (p)
 542                     p->next = t->next;
 543                   else
 544                     g_thread_all_threads = t->next;
 545                   break;
 546                 }
 547             }
 548           G_UNLOCK (g_thread);
 549
 550           /* Just to make sure, this isn't used any more */
 551           g_system_thread_assign (thread->system_thread, zero_thread);
 552           g_free (thread);
 553         }
 554     }
 555 }
 556
 557 static void
 558 g_thread_fail (void)
 559 {
 560   g_error ("The thread system is not yet initialized.");
 561 }
 562
 563 static gpointer
 564 g_thread_create_proxy (gpointer data)
 565 {
 566   GRealThread* thread = data;
 567
 568   g_assert (data);
 569
 570   /* This has to happen before G_LOCK, as that might call g_thread_self */
 571   g_private_set (g_thread_specific_private, data);
 572
 573   /* the lock makes sure, that thread->system_thread is written,
 574      before thread->thread.func is called. See g_thread_create. */
 575   G_LOCK (g_thread);
 576   G_UNLOCK (g_thread);
 577
 578   thread->retval = thread->thread.func (thread->thread.data);
 579
 580   return NULL;
 581 }
 582
 583 GThread*
 584 g_thread_create_full (GThreadFunc                func,
 585                       gpointer           data,
 586                       gulong             stack_size,
 587                       gboolean           joinable,
 588                       gboolean           bound,
 589                       GThreadPriority    priority,
 590                       GError                **error)
 591 {
 592   GRealThread* result;
 593   GError *local_error = NULL;
 594   g_return_val_if_fail (func, NULL);
 595   g_return_val_if_fail (priority >= G_THREAD_PRIORITY_LOW, NULL);
 596   g_return_val_if_fail (priority <= G_THREAD_PRIORITY_URGENT, NULL);
 597
 598   result = g_new0 (GRealThread, 1);
 599
 600   result->thread.joinable = joinable;
 601   result->thread.priority = priority;
 602   result->thread.func = func;
 603   result->thread.data = data;
 604   result->private_data = NULL;
 605   G_LOCK (g_thread);
 606   G_THREAD_UF (thread_create, (g_thread_create_proxy, result,
 607                                stack_size, joinable, bound, priority,
 608                                &result->system_thread, &local_error));
 609   result->next = g_thread_all_threads;
 610   g_thread_all_threads = result;
 611   G_UNLOCK (g_thread);
 612
 613   if (local_error)
 614     {
 615       g_propagate_error (error, local_error);
 616       g_free (result);
 617       return NULL;
 618     }
 619
 620   return (GThread*) result;
 621 }
 622
 623 void
 624 g_thread_exit (gpointer retval)
 625 {
 626   GRealThread* real = (GRealThread*) g_thread_self ();
 627   real->retval = retval;
 628   G_THREAD_CF (thread_exit, (void)0, ());
 629 }
 630
 631 gpointer
 632 g_thread_join (GThread* thread)
 633 {
 634   GRealThread* real = (GRealThread*) thread;
 635   GRealThread *p, *t;
 636   gpointer retval;
 637
 638   g_return_val_if_fail (thread, NULL);
 639   g_return_val_if_fail (thread->joinable, NULL);
 640   g_return_val_if_fail (!g_system_thread_equal (real->system_thread,
 641                                                 zero_thread), NULL);
 642
 643   G_THREAD_UF (thread_join, (&real->system_thread));
 644
 645   retval = real->retval;
 646
 647   G_LOCK (g_thread);
 648   for (t = g_thread_all_threads, p = NULL; t; p = t, t = t->next)
 649     {
 650       if (t == (GRealThread*) thread)
 651         {
 652           if (p)
 653             p->next = t->next;
 654           else
 655             g_thread_all_threads = t->next;
 656           break;
 657         }
 658     }
 659   G_UNLOCK (g_thread);
 660
 661   /* Just to make sure, this isn't used any more */
 662   thread->joinable = 0;
 663   g_system_thread_assign (real->system_thread, zero_thread);
 664
 665   /* the thread structure for non-joinable threads is freed upon
 666      thread end. We free the memory here. This will leave a loose end,
 667      if a joinable thread is not joined. */
 668
 669   g_free (thread);
 670
 671   return retval;
 672 }
 673
 674 void
 675 g_thread_set_priority (GThread* thread,
 676                        GThreadPriority priority)
 677 {
 678   GRealThread* real = (GRealThread*) thread;
 679
 680   g_return_if_fail (thread);
 681   g_return_if_fail (!g_system_thread_equal (real->system_thread, zero_thread));
 682   g_return_if_fail (priority >= G_THREAD_PRIORITY_LOW);
 683   g_return_if_fail (priority <= G_THREAD_PRIORITY_URGENT);
 684
 685   thread->priority = priority;
 686
 687   G_THREAD_CF (thread_set_priority, (void)0,
 688                (&real->system_thread, priority));
 689 }
 690
 691 GThread*
 692 g_thread_self (void)
 693 {
 694   GRealThread* thread = g_private_get (g_thread_specific_private);
 695
 696   if (!thread)
 697     {
 698       /* If no thread data is available, provide and set one.  This
 699          can happen for the main thread and for threads, that are not
 700          created by GLib. */
 701       thread = g_new0 (GRealThread, 1);
 702       thread->thread.joinable = FALSE; /* This is a save guess */
 703       thread->thread.priority = G_THREAD_PRIORITY_NORMAL; /* This is
 704                                                              just a guess */
 705       thread->thread.func = NULL;
 706       thread->thread.data = NULL;
 707       thread->private_data = NULL;
 708
 709       if (g_thread_supported ())
 710         G_THREAD_UF (thread_self, (&thread->system_thread));
 711
 712       g_private_set (g_thread_specific_private, thread);
 713
 714       G_LOCK (g_thread);
 715       thread->next = g_thread_all_threads;
 716       g_thread_all_threads = thread;
 717       G_UNLOCK (g_thread);
 718     }
 719
 720   return (GThread*)thread;
 721 }
 722
 723 void
 724 g_static_rw_lock_init (GStaticRWLock* lock)
 725 {
 726   static const GStaticRWLock init_lock = G_STATIC_RW_LOCK_INIT;
 727
 728   g_return_if_fail (lock);
 729
 730   *lock = init_lock;
 731 }
 732
 733 static void inline
 734 g_static_rw_lock_wait (GCond** cond, GStaticMutex* mutex)
 735 {
 736   if (!*cond)
 737       *cond = g_cond_new ();
 738   g_cond_wait (*cond, g_static_mutex_get_mutex (mutex));
 739 }
 740
 741 static void inline
 742 g_static_rw_lock_signal (GStaticRWLock* lock)
 743 {
 744   if (lock->want_to_write && lock->write_cond)
 745     g_cond_signal (lock->write_cond);
 746   else if (lock->want_to_read && lock->read_cond)
 747     g_cond_broadcast (lock->read_cond);
 748 }
 749
 750 void
 751 g_static_rw_lock_reader_lock (GStaticRWLock* lock)
 752 {
 753   g_return_if_fail (lock);
 754
 755   if (!g_threads_got_initialized)
 756     return;
 757
 758   g_static_mutex_lock (&lock->mutex);
 759   lock->want_to_read++;
 760   while (lock->have_writer || lock->want_to_write)
 761     g_static_rw_lock_wait (&lock->read_cond, &lock->mutex);
 762   lock->want_to_read--;
 763   lock->read_counter++;
 764   g_static_mutex_unlock (&lock->mutex);
 765 }
 766
 767 gboolean
 768 g_static_rw_lock_reader_trylock (GStaticRWLock* lock)
 769 {
 770   gboolean ret_val = FALSE;
 771
 772   g_return_val_if_fail (lock, FALSE);
 773
 774   if (!g_threads_got_initialized)
 775     return TRUE;
 776
 777   g_static_mutex_lock (&lock->mutex);
 778   if (!lock->have_writer && !lock->want_to_write)
 779     {
 780       lock->read_counter++;
 781       ret_val = TRUE;
 782     }
 783   g_static_mutex_unlock (&lock->mutex);
 784   return ret_val;
 785 }
 786
 787 void
 788 g_static_rw_lock_reader_unlock  (GStaticRWLock* lock)
 789 {
 790   g_return_if_fail (lock);
 791
 792   if (!g_threads_got_initialized)
 793     return;
 794
 795   g_static_mutex_lock (&lock->mutex);
 796   lock->read_counter--;
 797   if (lock->read_counter == 0)
 798     g_static_rw_lock_signal (lock);
 799   g_static_mutex_unlock (&lock->mutex);
 800 }
 801
 802 void
 803 g_static_rw_lock_writer_lock (GStaticRWLock* lock)
 804 {
 805   g_return_if_fail (lock);
 806
 807   if (!g_threads_got_initialized)
 808     return;
 809
 810   g_static_mutex_lock (&lock->mutex);
 811   lock->want_to_write++;
 812   while (lock->have_writer || lock->read_counter)
 813     g_static_rw_lock_wait (&lock->write_cond, &lock->mutex);
 814   lock->want_to_write--;
 815   lock->have_writer = TRUE;
 816   g_static_mutex_unlock (&lock->mutex);
 817 }
 818
 819 gboolean
 820 g_static_rw_lock_writer_trylock (GStaticRWLock* lock)
 821 {
 822   gboolean ret_val = FALSE;
 823
 824   g_return_val_if_fail (lock, FALSE);
 825
 826   if (!g_threads_got_initialized)
 827     return TRUE;
 828
 829   g_static_mutex_lock (&lock->mutex);
 830   if (!lock->have_writer && !lock->read_counter)
 831     {
 832       lock->have_writer = TRUE;
 833       ret_val = TRUE;
 834     }
 835   g_static_mutex_unlock (&lock->mutex);
 836   return ret_val;
 837 }
 838
 839 void
 840 g_static_rw_lock_writer_unlock (GStaticRWLock* lock)
 841 {
 842   g_return_if_fail (lock);
 843
 844   if (!g_threads_got_initialized)
 845     return;
 846
 847   g_static_mutex_lock (&lock->mutex);
 848   lock->have_writer = FALSE;
 849   g_static_rw_lock_signal (lock);
 850   g_static_mutex_unlock (&lock->mutex);
 851 }
 852
 853 void
 854 g_static_rw_lock_free (GStaticRWLock* lock)
 855 {
 856   g_return_if_fail (lock);
 857
 858   if (lock->read_cond)
 859     {
 860       g_cond_free (lock->read_cond);
 861       lock->read_cond = NULL;
 862     }
 863   if (lock->write_cond)
 864     {
 865       g_cond_free (lock->write_cond);
 866       lock->write_cond = NULL;
 867     }
 868   g_static_mutex_free (&lock->mutex);
 869 }
 870
 871 /*
 872  * Memory allocation can't use the regular GPrivate
 873  * API, since that relies on GArray, which uses
 874  * chunked memory.
 875  */
 876 gpointer
 877 _g_thread_mem_private_get (GThread *thread)
 878 {
 879   GRealThread *real_thread = (GRealThread*) thread;
 880
 881   return real_thread->mem_private;
 882 }
 883
 884 void
 885 _g_thread_mem_private_set (GThread *thread,
 886                            gpointer data)
 887 {
 888   GRealThread *real_thread = (GRealThread*) thread;
 889
 890   real_thread->mem_private = data;
 891 }
 892
 893 /**
 894  * g_thread_foreach
 895  * @thread_func: function to call for all GThread structures
 896  * @user_data:   second argument to @thread_func
 897  *
 898  * Call @thread_func on all existing #GThread structures. Note that
 899  * threads may decide to exit while @thread_func is running, so
 900  * without intimate knowledge about the lifetime of foreign threads,
 901  * @thread_func shouldn't access the GThread* pointer passed in as
 902  * first argument. However, @thread_func will not be called for threads
 903  * which are known to have exited already.
 904  *
 905  * Due to thread lifetime checks, this function has an execution complexity
 906  * which is quadratic in the number of existing threads.
 907  *
 908  * Since: 2.10
 909  */
 910 void
 911 g_thread_foreach (GFunc    thread_func,
 912                   gpointer user_data)
 913 {
 914   GSList *slist = NULL;
 915   GRealThread *thread;
 916   g_return_if_fail (thread_func != NULL);
 917   /* snapshot the list of threads for iteration */
 918   G_LOCK (g_thread);
 919   for (thread = g_thread_all_threads; thread; thread = thread->next)
 920     slist = g_slist_prepend (slist, thread);
 921   G_UNLOCK (g_thread);
 922   /* walk the list, skipping non-existant threads */
 923   while (slist)
 924     {
 925       GSList *node = slist;
 926       slist = node->next;
 927       /* check whether the current thread still exists */
 928       G_LOCK (g_thread);
 929       for (thread = g_thread_all_threads; thread; thread = thread->next)
 930         if (thread == node->data)
 931           break;
 932       G_UNLOCK (g_thread);
 933       if (thread)
 934         thread_func (thread, user_data);
 935       g_slist_free_1 (node);
 936     }
 937 }
 938
 939 #define __G_THREAD_C__
 940 #include "galiasdef.c"