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