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 /* implement gthread.h's inline functions */
  36 #define G_IMPLEMENT_INLINES 1
  37 #define __G_THREAD_C__
  38
  39 #include "config.h"
  40
  41 #include "glib.h"
  42 #include "gthreadprivate.h"
  43
  44 #ifdef HAVE_UNISTD_H
  45 #include <unistd.h>
  46 #endif
  47
  48 #ifndef G_OS_WIN32
  49 #include <sys/time.h>
  50 #include <time.h>
  51 #else
  52 #include <windows.h>
  53 #endif /* G_OS_WIN32 */
  54
  55 #include <string.h>
  56
  57 #include "galias.h"
  58
  59 GQuark
  60 g_thread_error_quark (void)
  61 {
  62   return g_quark_from_static_string ("g_thread_error");
  63 }
  64
  65 /* Keep this in sync with GRealThread in gmain.c! */
  66 typedef struct _GRealThread GRealThread;
  67 struct  _GRealThread
  68 {
  69   GThread thread;
  70   gpointer private_data;
  71   GRealThread *next;
  72   gpointer retval;
  73   GSystemThread system_thread;
  74 };
  75
  76 typedef struct _GStaticPrivateNode GStaticPrivateNode;
  77 struct _GStaticPrivateNode
  78 {
  79   gpointer       data;
  80   GDestroyNotify destroy;
  81 };
  82
  83 static void    g_thread_cleanup (gpointer data);
  84 static void    g_thread_fail (void);
  85 static guint64 gettime (void);
  86
  87 guint64        (*g_thread_gettime) (void) = gettime;
  88
  89 /* Global variables */
  90
  91 static GSystemThread zero_thread; /* This is initialized to all zero */
  92 gboolean g_thread_use_default_impl = TRUE;
  93 gboolean g_threads_got_initialized = FALSE;
  94
  95 GThreadFunctions g_thread_functions_for_glib_use = {
  96   (GMutex*(*)())g_thread_fail,                 /* mutex_new */
  97   NULL,                                        /* mutex_lock */
  98   NULL,                                        /* mutex_trylock */
  99   NULL,                                        /* mutex_unlock */
 100   NULL,                                        /* mutex_free */
 101   (GCond*(*)())g_thread_fail,                  /* cond_new */
 102   NULL,                                        /* cond_signal */
 103   NULL,                                        /* cond_broadcast */
 104   NULL,                                        /* cond_wait */
 105   NULL,                                        /* cond_timed_wait  */
 106   NULL,                                        /* cond_free */
 107   (GPrivate*(*)(GDestroyNotify))g_thread_fail, /* private_new */
 108   NULL,                                        /* private_get */
 109   NULL,                                        /* private_set */
 110   (void(*)(GThreadFunc, gpointer, gulong,
 111            gboolean, gboolean, GThreadPriority,
 112            gpointer, GError**))g_thread_fail,  /* thread_create */
 113   NULL,                                        /* thread_yield */
 114   NULL,                                        /* thread_join */
 115   NULL,                                        /* thread_exit */
 116   NULL,                                        /* thread_set_priority */
 117   NULL,                                        /* thread_self */
 118   NULL                                         /* thread_equal */
 119 };
 120
 121 /* Local data */
 122
 123 static GMutex   *g_once_mutex = NULL;
 124 static GCond    *g_once_cond = NULL;
 125 static GPrivate *g_thread_specific_private = NULL;
 126 static GRealThread *g_thread_all_threads = NULL;
 127 static GSList   *g_thread_free_indeces = NULL;
 128 static GSList*   g_once_init_list = NULL;
 129
 130 G_LOCK_DEFINE_STATIC (g_thread);
 131
 132 #ifdef G_THREADS_ENABLED
 133 /* This must be called only once, before any threads are created.
 134  * It will only be called from g_thread_init() in -lgthread.
 135  */
 136 void
 137 g_thread_init_glib (void)
 138 {
 139   /* We let the main thread (the one that calls g_thread_init) inherit
 140    * the static_private data set before calling g_thread_init
 141    */
 142   GRealThread* main_thread = (GRealThread*) g_thread_self ();
 143
 144   /* mutex and cond creation works without g_threads_got_initialized */
 145   g_once_mutex = g_mutex_new ();
 146   g_once_cond = g_cond_new ();
 147
 148   /* we may only create mutex and cond in here */
 149   _g_mem_thread_init_noprivate_nomessage ();
 150
 151   /* setup the basic threading system */
 152   g_threads_got_initialized = TRUE;
 153   g_thread_specific_private = g_private_new (g_thread_cleanup);
 154   g_private_set (g_thread_specific_private, main_thread);
 155   G_THREAD_UF (thread_self, (&main_thread->system_thread));
 156
 157   /* complete memory system initialization, g_private_*() works now */
 158   _g_slice_thread_init_nomessage ();
 159
 160   /* accomplish log system initialization to enable messaging */
 161   _g_messages_thread_init_nomessage ();
 162
 163   /* we may run full-fledged initializers from here */
 164   _g_atomic_thread_init ();
 165   _g_convert_thread_init ();
 166   _g_rand_thread_init ();
 167   _g_main_thread_init ();
 168   _g_utils_thread_init ();
 169   _g_futex_thread_init ();
 170 #ifdef G_OS_WIN32
 171   _g_win32_thread_init ();
 172 #endif
 173 }
 174 #endif /* G_THREADS_ENABLED */
 175
 176 gpointer
 177 g_once_impl (GOnce       *once,
 178              GThreadFunc  func,
 179              gpointer     arg)
 180 {
 181   g_mutex_lock (g_once_mutex);
 182
 183   while (once->status == G_ONCE_STATUS_PROGRESS)
 184     g_cond_wait (g_once_cond, g_once_mutex);
 185
 186   if (once->status != G_ONCE_STATUS_READY)
 187     {
 188       once->status = G_ONCE_STATUS_PROGRESS;
 189       g_mutex_unlock (g_once_mutex);
 190
 191       once->retval = func (arg);
 192
 193       g_mutex_lock (g_once_mutex);
 194       once->status = G_ONCE_STATUS_READY;
 195       g_cond_broadcast (g_once_cond);
 196     }
 197
 198   g_mutex_unlock (g_once_mutex);
 199
 200   return once->retval;
 201 }
 202
 203 gboolean
 204 g_once_init_enter_impl (volatile gsize *value_location)
 205 {
 206   gboolean need_init = FALSE;
 207   g_mutex_lock (g_once_mutex);
 208   if (g_atomic_pointer_get (value_location) == NULL)
 209     {
 210       if (!g_slist_find (g_once_init_list, (void*) value_location))
 211         {
 212           need_init = TRUE;
 213           g_once_init_list = g_slist_prepend (g_once_init_list, (void*) value_location);
 214         }
 215       else
 216         do
 217           g_cond_wait (g_once_cond, g_once_mutex);
 218         while (g_slist_find (g_once_init_list, (void*) value_location));
 219     }
 220   g_mutex_unlock (g_once_mutex);
 221   return need_init;
 222 }
 223
 224 void
 225 g_once_init_leave (volatile gsize *value_location,
 226                    gsize           initialization_value)
 227 {
 228   g_return_if_fail (g_atomic_pointer_get (value_location) == NULL);
 229   g_return_if_fail (initialization_value != 0);
 230   g_return_if_fail (g_once_init_list != NULL);
 231
 232   g_atomic_pointer_set ((void**)value_location, (void*) initialization_value);
 233   g_mutex_lock (g_once_mutex);
 234   g_once_init_list = g_slist_remove (g_once_init_list, (void*) value_location);
 235   g_cond_broadcast (g_once_cond);
 236   g_mutex_unlock (g_once_mutex);
 237 }
 238
 239 void
 240 g_static_mutex_init (GStaticMutex *mutex)
 241 {
 242   static const GStaticMutex init_mutex = G_STATIC_MUTEX_INIT;
 243
 244   g_return_if_fail (mutex);
 245
 246   *mutex = init_mutex;
 247 }
 248
 249 GMutex *
 250 g_static_mutex_get_mutex_impl (GMutex** mutex)
 251 {
 252   if (!g_thread_supported ())
 253     return NULL;
 254
 255   g_assert (g_once_mutex);
 256
 257   g_mutex_lock (g_once_mutex);
 258
 259   if (!(*mutex))
 260     g_atomic_pointer_set (mutex, g_mutex_new());
 261
 262   g_mutex_unlock (g_once_mutex);
 263
 264   return *mutex;
 265 }
 266
 267 void
 268 g_static_mutex_free (GStaticMutex* mutex)
 269 {
 270   GMutex **runtime_mutex;
 271
 272   g_return_if_fail (mutex);
 273
 274   /* The runtime_mutex is the first (or only) member of GStaticMutex,
 275    * see both versions (of glibconfig.h) in configure.in. Note, that
 276    * this variable is NULL, if g_thread_init() hasn't been called or
 277    * if we're using the default thread implementation and it provides
 278    * static mutexes. */
 279   runtime_mutex = ((GMutex**)mutex);
 280
 281   if (*runtime_mutex)
 282     g_mutex_free (*runtime_mutex);
 283
 284   *runtime_mutex = NULL;
 285 }
 286
 287 void
 288 g_static_rec_mutex_init (GStaticRecMutex *mutex)
 289 {
 290   static const GStaticRecMutex init_mutex = G_STATIC_REC_MUTEX_INIT;
 291
 292   g_return_if_fail (mutex);
 293
 294   *mutex = init_mutex;
 295 }
 296
 297 void
 298 g_static_rec_mutex_lock (GStaticRecMutex* mutex)
 299 {
 300   GSystemThread self;
 301
 302   g_return_if_fail (mutex);
 303
 304   if (!g_thread_supported ())
 305     return;
 306
 307   G_THREAD_UF (thread_self, (&self));
 308
 309   if (g_system_thread_equal (self, mutex->owner))
 310     {
 311       mutex->depth++;
 312       return;
 313     }
 314   g_static_mutex_lock (&mutex->mutex);
 315   g_system_thread_assign (mutex->owner, self);
 316   mutex->depth = 1;
 317 }
 318
 319 gboolean
 320 g_static_rec_mutex_trylock (GStaticRecMutex* mutex)
 321 {
 322   GSystemThread self;
 323
 324   g_return_val_if_fail (mutex, FALSE);
 325
 326   if (!g_thread_supported ())
 327     return TRUE;
 328
 329   G_THREAD_UF (thread_self, (&self));
 330
 331   if (g_system_thread_equal (self, mutex->owner))
 332     {
 333       mutex->depth++;
 334       return TRUE;
 335     }
 336
 337   if (!g_static_mutex_trylock (&mutex->mutex))
 338     return FALSE;
 339
 340   g_system_thread_assign (mutex->owner, self);
 341   mutex->depth = 1;
 342   return TRUE;
 343 }
 344
 345 void
 346 g_static_rec_mutex_unlock (GStaticRecMutex* mutex)
 347 {
 348   g_return_if_fail (mutex);
 349
 350   if (!g_thread_supported ())
 351     return;
 352
 353   if (mutex->depth > 1)
 354     {
 355       mutex->depth--;
 356       return;
 357     }
 358   g_system_thread_assign (mutex->owner, zero_thread);
 359   g_static_mutex_unlock (&mutex->mutex);
 360 }
 361
 362 void
 363 g_static_rec_mutex_lock_full   (GStaticRecMutex *mutex,
 364                                 guint            depth)
 365 {
 366   GSystemThread self;
 367   g_return_if_fail (mutex);
 368
 369   if (!g_thread_supported ())
 370     return;
 371
 372   if (depth == 0)
 373     return;
 374
 375   G_THREAD_UF (thread_self, (&self));
 376
 377   if (g_system_thread_equal (self, mutex->owner))
 378     {
 379       mutex->depth += depth;
 380       return;
 381     }
 382   g_static_mutex_lock (&mutex->mutex);
 383   g_system_thread_assign (mutex->owner, self);
 384   mutex->depth = depth;
 385 }
 386
 387 guint
 388 g_static_rec_mutex_unlock_full (GStaticRecMutex *mutex)
 389 {
 390   guint depth;
 391
 392   g_return_val_if_fail (mutex, 0);
 393
 394   if (!g_thread_supported ())
 395     return 1;
 396
 397   depth = mutex->depth;
 398
 399   g_system_thread_assign (mutex->owner, zero_thread);
 400   mutex->depth = 0;
 401   g_static_mutex_unlock (&mutex->mutex);
 402
 403   return depth;
 404 }
 405
 406 void
 407 g_static_rec_mutex_free (GStaticRecMutex *mutex)
 408 {
 409   g_return_if_fail (mutex);
 410
 411   g_static_mutex_free (&mutex->mutex);
 412 }
 413
 414 void
 415 g_static_private_init (GStaticPrivate *private_key)
 416 {
 417   private_key->index = 0;
 418 }
 419
 420 gpointer
 421 g_static_private_get (GStaticPrivate *private_key)
 422 {
 423   GRealThread *self = (GRealThread*) g_thread_self ();
 424   GArray *array;
 425
 426   array = self->private_data;
 427   if (!array)
 428     return NULL;
 429
 430   if (!private_key->index)
 431     return NULL;
 432   else if (private_key->index <= array->len)
 433     return g_array_index (array, GStaticPrivateNode,
 434                           private_key->index - 1).data;
 435   else
 436     return NULL;
 437 }
 438
 439 void
 440 g_static_private_set (GStaticPrivate *private_key,
 441                       gpointer        data,
 442                       GDestroyNotify  notify)
 443 {
 444   GRealThread *self = (GRealThread*) g_thread_self ();
 445   GArray *array;
 446   static guint next_index = 0;
 447   GStaticPrivateNode *node;
 448
 449   array = self->private_data;
 450   if (!array)
 451     {
 452       array = g_array_new (FALSE, TRUE, sizeof (GStaticPrivateNode));
 453       self->private_data = array;
 454     }
 455
 456   if (!private_key->index)
 457     {
 458       G_LOCK (g_thread);
 459
 460       if (!private_key->index)
 461         {
 462           if (g_thread_free_indeces)
 463             {
 464               private_key->index =
 465                 GPOINTER_TO_UINT (g_thread_free_indeces->data);
 466               g_thread_free_indeces =
 467                 g_slist_delete_link (g_thread_free_indeces,
 468                                      g_thread_free_indeces);
 469             }
 470           else
 471             private_key->index = ++next_index;
 472         }
 473
 474       G_UNLOCK (g_thread);
 475     }
 476
 477   if (private_key->index > array->len)
 478     g_array_set_size (array, private_key->index);
 479
 480   node = &g_array_index (array, GStaticPrivateNode, private_key->index - 1);
 481   if (node->destroy)
 482     {
 483       gpointer ddata = node->data;
 484       GDestroyNotify ddestroy = node->destroy;
 485
 486       node->data = data;
 487       node->destroy = notify;
 488
 489       ddestroy (ddata);
 490     }
 491   else
 492     {
 493       node->data = data;
 494       node->destroy = notify;
 495     }
 496 }
 497
 498 void
 499 g_static_private_free (GStaticPrivate *private_key)
 500 {
 501   guint idx = private_key->index;
 502   GRealThread *thread;
 503
 504   if (!idx)
 505     return;
 506
 507   private_key->index = 0;
 508
 509   G_LOCK (g_thread);
 510
 511   thread = g_thread_all_threads;
 512   while (thread)
 513     {
 514       GArray *array = thread->private_data;
 515       thread = thread->next;
 516
 517       if (array && idx <= array->len)
 518         {
 519           GStaticPrivateNode *node = &g_array_index (array,
 520                                                      GStaticPrivateNode,
 521                                                      idx - 1);
 522           gpointer ddata = node->data;
 523           GDestroyNotify ddestroy = node->destroy;
 524
 525           node->data = NULL;
 526           node->destroy = NULL;
 527
 528           if (ddestroy)
 529             {
 530               G_UNLOCK (g_thread);
 531               ddestroy (ddata);
 532               G_LOCK (g_thread);
 533             }
 534         }
 535     }
 536   g_thread_free_indeces = g_slist_prepend (g_thread_free_indeces,
 537                                            GUINT_TO_POINTER (idx));
 538   G_UNLOCK (g_thread);
 539 }
 540
 541 static void
 542 g_thread_cleanup (gpointer data)
 543 {
 544   if (data)
 545     {
 546       GRealThread* thread = data;
 547       if (thread->private_data)
 548         {
 549           GArray* array = thread->private_data;
 550           guint i;
 551
 552           for (i = 0; i < array->len; i++ )
 553             {
 554               GStaticPrivateNode *node =
 555                 &g_array_index (array, GStaticPrivateNode, i);
 556               if (node->destroy)
 557                 node->destroy (node->data);
 558             }
 559           g_array_free (array, TRUE);
 560         }
 561
 562       /* We only free the thread structure, if it isn't joinable. If
 563          it is, the structure is freed in g_thread_join */
 564       if (!thread->thread.joinable)
 565         {
 566           GRealThread *t, *p;
 567
 568           G_LOCK (g_thread);
 569           for (t = g_thread_all_threads, p = NULL; t; p = t, t = t->next)
 570             {
 571               if (t == thread)
 572                 {
 573                   if (p)
 574                     p->next = t->next;
 575                   else
 576                     g_thread_all_threads = t->next;
 577                   break;
 578                 }
 579             }
 580           G_UNLOCK (g_thread);
 581
 582           /* Just to make sure, this isn't used any more */
 583           g_system_thread_assign (thread->system_thread, zero_thread);
 584           g_free (thread);
 585         }
 586     }
 587 }
 588
 589 static void
 590 g_thread_fail (void)
 591 {
 592   g_error ("The thread system is not yet initialized.");
 593 }
 594
 595 #define G_NSEC_PER_SEC 1000000000
 596
 597 static guint64
 598 gettime (void)
 599 {
 600 #ifdef G_OS_WIN32
 601   guint64 v;
 602
 603   /* Returns 100s of nanoseconds since start of 1601 */
 604   GetSystemTimeAsFileTime ((FILETIME *)&v);
 605
 606   /* Offset to Unix epoch */
 607   v -= G_GINT64_CONSTANT (116444736000000000);
 608   /* Convert to nanoseconds */
 609   v *= 100;
 610
 611   return v;
 612 #else
 613   struct timeval tv;
 614
 615   gettimeofday (&tv, NULL);
 616
 617   return (guint64) tv.tv_sec * G_NSEC_PER_SEC + tv.tv_usec * (G_NSEC_PER_SEC / G_USEC_PER_SEC);
 618 #endif
 619 }
 620
 621 static gpointer
 622 g_thread_create_proxy (gpointer data)
 623 {
 624   GRealThread* thread = data;
 625
 626   g_assert (data);
 627
 628   /* This has to happen before G_LOCK, as that might call g_thread_self */
 629   g_private_set (g_thread_specific_private, data);
 630
 631   /* the lock makes sure, that thread->system_thread is written,
 632      before thread->thread.func is called. See g_thread_create. */
 633   G_LOCK (g_thread);
 634   G_UNLOCK (g_thread);
 635
 636   thread->retval = thread->thread.func (thread->thread.data);
 637
 638   return NULL;
 639 }
 640
 641 GThread*
 642 g_thread_create_full (GThreadFunc       func,
 643                       gpointer          data,
 644                       gulong            stack_size,
 645                       gboolean          joinable,
 646                       gboolean          bound,
 647                       GThreadPriority   priority,
 648                       GError          **error)
 649 {
 650   GRealThread* result;
 651   GError *local_error = NULL;
 652   g_return_val_if_fail (func, NULL);
 653   g_return_val_if_fail (priority >= G_THREAD_PRIORITY_LOW, NULL);
 654   g_return_val_if_fail (priority <= G_THREAD_PRIORITY_URGENT, NULL);
 655
 656   result = g_new0 (GRealThread, 1);
 657
 658   result->thread.joinable = joinable;
 659   result->thread.priority = priority;
 660   result->thread.func = func;
 661   result->thread.data = data;
 662   result->private_data = NULL;
 663   G_LOCK (g_thread);
 664   G_THREAD_UF (thread_create, (g_thread_create_proxy, result,
 665                                stack_size, joinable, bound, priority,
 666                                &result->system_thread, &local_error));
 667   if (!local_error)
 668     {
 669       result->next = g_thread_all_threads;
 670       g_thread_all_threads = result;
 671     }
 672   G_UNLOCK (g_thread);
 673
 674   if (local_error)
 675     {
 676       g_propagate_error (error, local_error);
 677       g_free (result);
 678       return NULL;
 679     }
 680
 681   return (GThread*) result;
 682 }
 683
 684 void
 685 g_thread_exit (gpointer retval)
 686 {
 687   GRealThread* real = (GRealThread*) g_thread_self ();
 688   real->retval = retval;
 689   G_THREAD_CF (thread_exit, (void)0, ());
 690 }
 691
 692 gpointer
 693 g_thread_join (GThread* thread)
 694 {
 695   GRealThread* real = (GRealThread*) thread;
 696   GRealThread *p, *t;
 697   gpointer retval;
 698
 699   g_return_val_if_fail (thread, NULL);
 700   g_return_val_if_fail (thread->joinable, NULL);
 701   g_return_val_if_fail (!g_system_thread_equal (real->system_thread,
 702                                                 zero_thread), NULL);
 703
 704   G_THREAD_UF (thread_join, (&real->system_thread));
 705
 706   retval = real->retval;
 707
 708   G_LOCK (g_thread);
 709   for (t = g_thread_all_threads, p = NULL; t; p = t, t = t->next)
 710     {
 711       if (t == (GRealThread*) thread)
 712         {
 713           if (p)
 714             p->next = t->next;
 715           else
 716             g_thread_all_threads = t->next;
 717           break;
 718         }
 719     }
 720   G_UNLOCK (g_thread);
 721
 722   /* Just to make sure, this isn't used any more */
 723   thread->joinable = 0;
 724   g_system_thread_assign (real->system_thread, zero_thread);
 725
 726   /* the thread structure for non-joinable threads is freed upon
 727      thread end. We free the memory here. This will leave a loose end,
 728      if a joinable thread is not joined. */
 729
 730   g_free (thread);
 731
 732   return retval;
 733 }
 734
 735 void
 736 g_thread_set_priority (GThread* thread,
 737                        GThreadPriority priority)
 738 {
 739   GRealThread* real = (GRealThread*) thread;
 740
 741   g_return_if_fail (thread);
 742   g_return_if_fail (!g_system_thread_equal (real->system_thread, zero_thread));
 743   g_return_if_fail (priority >= G_THREAD_PRIORITY_LOW);
 744   g_return_if_fail (priority <= G_THREAD_PRIORITY_URGENT);
 745
 746   thread->priority = priority;
 747
 748   G_THREAD_CF (thread_set_priority, (void)0,
 749                (&real->system_thread, priority));
 750 }
 751
 752 GThread*
 753 g_thread_self (void)
 754 {
 755   GRealThread* thread = g_private_get (g_thread_specific_private);
 756
 757   if (!thread)
 758     {
 759       /* If no thread data is available, provide and set one.  This
 760          can happen for the main thread and for threads, that are not
 761          created by GLib. */
 762       thread = g_new0 (GRealThread, 1);
 763       thread->thread.joinable = FALSE; /* This is a save guess */
 764       thread->thread.priority = G_THREAD_PRIORITY_NORMAL; /* This is
 765                                                              just a guess */
 766       thread->thread.func = NULL;
 767       thread->thread.data = NULL;
 768       thread->private_data = NULL;
 769
 770       if (g_thread_supported ())
 771         G_THREAD_UF (thread_self, (&thread->system_thread));
 772
 773       g_private_set (g_thread_specific_private, thread);
 774
 775       G_LOCK (g_thread);
 776       thread->next = g_thread_all_threads;
 777       g_thread_all_threads = thread;
 778       G_UNLOCK (g_thread);
 779     }
 780
 781   return (GThread*)thread;
 782 }
 783
 784 void
 785 g_static_rw_lock_init (GStaticRWLock* lock)
 786 {
 787   static const GStaticRWLock init_lock = G_STATIC_RW_LOCK_INIT;
 788
 789   g_return_if_fail (lock);
 790
 791   *lock = init_lock;
 792 }
 793
 794 inline static void
 795 g_static_rw_lock_wait (GCond** cond, GStaticMutex* mutex)
 796 {
 797   if (!*cond)
 798       *cond = g_cond_new ();
 799   g_cond_wait (*cond, g_static_mutex_get_mutex (mutex));
 800 }
 801
 802 inline static void
 803 g_static_rw_lock_signal (GStaticRWLock* lock)
 804 {
 805   if (lock->want_to_write && lock->write_cond)
 806     g_cond_signal (lock->write_cond);
 807   else if (lock->want_to_read && lock->read_cond)
 808     g_cond_broadcast (lock->read_cond);
 809 }
 810
 811 void
 812 g_static_rw_lock_reader_lock (GStaticRWLock* lock)
 813 {
 814   g_return_if_fail (lock);
 815
 816   if (!g_threads_got_initialized)
 817     return;
 818
 819   g_static_mutex_lock (&lock->mutex);
 820   lock->want_to_read++;
 821   while (lock->have_writer || lock->want_to_write)
 822     g_static_rw_lock_wait (&lock->read_cond, &lock->mutex);
 823   lock->want_to_read--;
 824   lock->read_counter++;
 825   g_static_mutex_unlock (&lock->mutex);
 826 }
 827
 828 gboolean
 829 g_static_rw_lock_reader_trylock (GStaticRWLock* lock)
 830 {
 831   gboolean ret_val = FALSE;
 832
 833   g_return_val_if_fail (lock, FALSE);
 834
 835   if (!g_threads_got_initialized)
 836     return TRUE;
 837
 838   g_static_mutex_lock (&lock->mutex);
 839   if (!lock->have_writer && !lock->want_to_write)
 840     {
 841       lock->read_counter++;
 842       ret_val = TRUE;
 843     }
 844   g_static_mutex_unlock (&lock->mutex);
 845   return ret_val;
 846 }
 847
 848 void
 849 g_static_rw_lock_reader_unlock  (GStaticRWLock* lock)
 850 {
 851   g_return_if_fail (lock);
 852
 853   if (!g_threads_got_initialized)
 854     return;
 855
 856   g_static_mutex_lock (&lock->mutex);
 857   lock->read_counter--;
 858   if (lock->read_counter == 0)
 859     g_static_rw_lock_signal (lock);
 860   g_static_mutex_unlock (&lock->mutex);
 861 }
 862
 863 void
 864 g_static_rw_lock_writer_lock (GStaticRWLock* lock)
 865 {
 866   g_return_if_fail (lock);
 867
 868   if (!g_threads_got_initialized)
 869     return;
 870
 871   g_static_mutex_lock (&lock->mutex);
 872   lock->want_to_write++;
 873   while (lock->have_writer || lock->read_counter)
 874     g_static_rw_lock_wait (&lock->write_cond, &lock->mutex);
 875   lock->want_to_write--;
 876   lock->have_writer = TRUE;
 877   g_static_mutex_unlock (&lock->mutex);
 878 }
 879
 880 gboolean
 881 g_static_rw_lock_writer_trylock (GStaticRWLock* lock)
 882 {
 883   gboolean ret_val = FALSE;
 884
 885   g_return_val_if_fail (lock, FALSE);
 886
 887   if (!g_threads_got_initialized)
 888     return TRUE;
 889
 890   g_static_mutex_lock (&lock->mutex);
 891   if (!lock->have_writer && !lock->read_counter)
 892     {
 893       lock->have_writer = TRUE;
 894       ret_val = TRUE;
 895     }
 896   g_static_mutex_unlock (&lock->mutex);
 897   return ret_val;
 898 }
 899
 900 void
 901 g_static_rw_lock_writer_unlock (GStaticRWLock* lock)
 902 {
 903   g_return_if_fail (lock);
 904
 905   if (!g_threads_got_initialized)
 906     return;
 907
 908   g_static_mutex_lock (&lock->mutex);
 909   lock->have_writer = FALSE;
 910   g_static_rw_lock_signal (lock);
 911   g_static_mutex_unlock (&lock->mutex);
 912 }
 913
 914 void
 915 g_static_rw_lock_free (GStaticRWLock* lock)
 916 {
 917   g_return_if_fail (lock);
 918
 919   if (lock->read_cond)
 920     {
 921       g_cond_free (lock->read_cond);
 922       lock->read_cond = NULL;
 923     }
 924   if (lock->write_cond)
 925     {
 926       g_cond_free (lock->write_cond);
 927       lock->write_cond = NULL;
 928     }
 929   g_static_mutex_free (&lock->mutex);
 930 }
 931
 932 /**
 933  * g_thread_foreach
 934  * @thread_func: function to call for all GThread structures
 935  * @user_data:   second argument to @thread_func
 936  *
 937  * Call @thread_func on all existing #GThread structures. Note that
 938  * threads may decide to exit while @thread_func is running, so
 939  * without intimate knowledge about the lifetime of foreign threads,
 940  * @thread_func shouldn't access the GThread* pointer passed in as
 941  * first argument. However, @thread_func will not be called for threads
 942  * which are known to have exited already.
 943  *
 944  * Due to thread lifetime checks, this function has an execution complexity
 945  * which is quadratic in the number of existing threads.
 946  *
 947  * Since: 2.10
 948  */
 949 void
 950 g_thread_foreach (GFunc    thread_func,
 951                   gpointer user_data)
 952 {
 953   GSList *slist = NULL;
 954   GRealThread *thread;
 955   g_return_if_fail (thread_func != NULL);
 956   /* snapshot the list of threads for iteration */
 957   G_LOCK (g_thread);
 958   for (thread = g_thread_all_threads; thread; thread = thread->next)
 959     slist = g_slist_prepend (slist, thread);
 960   G_UNLOCK (g_thread);
 961   /* walk the list, skipping non-existant threads */
 962   while (slist)
 963     {
 964       GSList *node = slist;
 965       slist = node->next;
 966       /* check whether the current thread still exists */
 967       G_LOCK (g_thread);
 968       for (thread = g_thread_all_threads; thread; thread = thread->next)
 969         if (thread == node->data)
 970           break;
 971       G_UNLOCK (g_thread);
 972       if (thread)
 973         thread_func (thread, user_data);
 974       g_slist_free_1 (node);
 975     }
 976 }
 977
 978 /**
 979  * g_thread_get_initialized
 980  *
 981  * Indicates if g_thread_init() has been called.
 982  *
 983  * Returns: %TRUE if threads have been initialized.
 984  *
 985  * Since: 2.20
 986  */
 987 gboolean
 988 g_thread_get_initialized ()
 989 {
 990   return g_thread_supported ();
 991 }
 992
 993 #define __G_THREAD_C__
 994 #include "galiasdef.c"