glib/gthread.h

   1 /* GLIB - Library of useful routines for C programming
   2  * Copyright (C) 1995-1997  Peter Mattis, Spencer Kimball and Josh MacDonald
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, write to the
  16  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17  * Boston, MA 02111-1307, USA.
  18  */
  19
  20 /*
  21  * Modified by the GLib Team and others 1997-2000.  See the AUTHORS
  22  * file for a list of people on the GLib Team.  See the ChangeLog
  23  * files for a list of changes.  These files are distributed with
  24  * GLib at ftp://ftp.gtk.org/pub/gtk/.
  25  */
  26
  27 #if defined(G_DISABLE_SINGLE_INCLUDES) && !defined (__GLIB_H_INSIDE__) && !defined (GLIB_COMPILATION)
  28 #error "Only <glib.h> can be included directly."
  29 #endif
  30
  31 #ifndef __G_THREAD_H__
  32 #define __G_THREAD_H__
  33
  34 #include <glib/gerror.h>
  35 #include <glib/gutils.h>        /* for G_INLINE_FUNC */
  36 #include <glib/gatomic.h>       /* for g_atomic_pointer_get */
  37
  38 G_BEGIN_DECLS
  39
  40 /* GLib Thread support
  41  */
  42
  43 extern GQuark g_thread_error_quark (void);
  44 #define G_THREAD_ERROR g_thread_error_quark ()
  45
  46 typedef enum
  47 {
  48   G_THREAD_ERROR_AGAIN /* Resource temporarily unavailable */
  49 } GThreadError;
  50
  51 typedef gpointer (*GThreadFunc) (gpointer data);
  52
  53 typedef enum
  54 {
  55   G_THREAD_PRIORITY_LOW,
  56   G_THREAD_PRIORITY_NORMAL,
  57   G_THREAD_PRIORITY_HIGH,
  58   G_THREAD_PRIORITY_URGENT
  59 } GThreadPriority;
  60
  61 typedef struct _GThread         GThread;
  62 struct  _GThread
  63 {
  64   /*< private >*/
  65   GThreadFunc func;
  66   gpointer data;
  67   gboolean joinable;
  68   GThreadPriority priority;
  69 };
  70
  71 typedef struct _GMutex          GMutex;
  72 typedef struct _GCond           GCond;
  73 typedef struct _GPrivate        GPrivate;
  74 typedef struct _GStaticPrivate  GStaticPrivate;
  75
  76 typedef struct _GThreadFunctions GThreadFunctions;
  77 struct _GThreadFunctions
  78 {
  79   GMutex*  (*mutex_new)           (void);
  80   void     (*mutex_lock)          (GMutex               *mutex);
  81   gboolean (*mutex_trylock)       (GMutex               *mutex);
  82   void     (*mutex_unlock)        (GMutex               *mutex);
  83   void     (*mutex_free)          (GMutex               *mutex);
  84   GCond*   (*cond_new)            (void);
  85   void     (*cond_signal)         (GCond                *cond);
  86   void     (*cond_broadcast)      (GCond                *cond);
  87   void     (*cond_wait)           (GCond                *cond,
  88                                    GMutex               *mutex);
  89   gboolean (*cond_timed_wait)     (GCond                *cond,
  90                                    GMutex               *mutex,
  91                                    GTimeVal             *end_time);
  92   void      (*cond_free)          (GCond                *cond);
  93   GPrivate* (*private_new)        (GDestroyNotify        destructor);
  94   gpointer  (*private_get)        (GPrivate             *private_key);
  95   void      (*private_set)        (GPrivate             *private_key,
  96                                    gpointer              data);
  97   void      (*thread_create)      (GThreadFunc           func,
  98                                    gpointer              data,
  99                                    gulong                stack_size,
 100                                    gboolean              joinable,
 101                                    gboolean              bound,
 102                                    GThreadPriority       priority,
 103                                    gpointer              thread,
 104                                    GError              **error);
 105   void      (*thread_yield)       (void);
 106   void      (*thread_join)        (gpointer              thread);
 107   void      (*thread_exit)        (void);
 108   void      (*thread_set_priority)(gpointer              thread,
 109                                    GThreadPriority       priority);
 110   void      (*thread_self)        (gpointer              thread);
 111   gboolean  (*thread_equal)       (gpointer              thread1,
 112                                    gpointer              thread2);
 113 };
 114
 115 GLIB_VAR GThreadFunctions       g_thread_functions_for_glib_use;
 116 GLIB_VAR gboolean               g_thread_use_default_impl;
 117 GLIB_VAR gboolean               g_threads_got_initialized;
 118
 119 GLIB_VAR guint64   (*g_thread_gettime) (void);
 120
 121 /* initializes the mutex/cond/private implementation for glib, might
 122  * only be called once, and must not be called directly or indirectly
 123  * from another glib-function, e.g. as a callback.
 124  */
 125 void    g_thread_init   (GThreadFunctions       *vtable);
 126
 127 /* Errorcheck mutexes. If you define G_ERRORCHECK_MUTEXES, then all
 128  * mutexes will check for re-locking and re-unlocking */
 129
 130 /* Initialize thread system with errorcheck mutexes. vtable must be
 131  * NULL. Do not call directly. Use #define G_ERRORCHECK_MUTEXES
 132  * instead.
 133  */
 134 void    g_thread_init_with_errorcheck_mutexes (GThreadFunctions* vtable);
 135
 136 /* Checks if thread support is initialized.  Identical to the
 137  * g_thread_supported macro but provided for language bindings.
 138  */
 139 gboolean g_thread_get_initialized (void);
 140
 141 /* A random number to recognize debug calls to g_mutex_... */
 142 #define G_MUTEX_DEBUG_MAGIC 0xf8e18ad7
 143
 144 #ifdef G_ERRORCHECK_MUTEXES
 145 #define g_thread_init(vtable) g_thread_init_with_errorcheck_mutexes (vtable)
 146 #endif
 147
 148 /* internal function for fallback static mutex implementation */
 149 GMutex* g_static_mutex_get_mutex_impl   (GMutex **mutex);
 150
 151 #define g_static_mutex_get_mutex_impl_shortcut(mutex) \
 152   (g_atomic_pointer_get (mutex) ? *(mutex) : \
 153    g_static_mutex_get_mutex_impl (mutex))
 154
 155 /* shorthands for conditional and unconditional function calls */
 156
 157 #define G_THREAD_UF(op, arglist)                                        \
 158     (*g_thread_functions_for_glib_use . op) arglist
 159 #define G_THREAD_CF(op, fail, arg)                                      \
 160     (g_thread_supported () ? G_THREAD_UF (op, arg) : (fail))
 161 #define G_THREAD_ECF(op, fail, mutex, type)                             \
 162     (g_thread_supported () ?                                            \
 163       ((type(*)(GMutex*, const gulong, gchar const*))                   \
 164       (*g_thread_functions_for_glib_use . op))                          \
 165      (mutex, G_MUTEX_DEBUG_MAGIC, G_STRLOC) : (fail))
 166
 167 #ifndef G_ERRORCHECK_MUTEXES
 168 # define g_mutex_lock(mutex)                                            \
 169     G_THREAD_CF (mutex_lock,     (void)0, (mutex))
 170 # define g_mutex_trylock(mutex)                                         \
 171     G_THREAD_CF (mutex_trylock,  TRUE,    (mutex))
 172 # define g_mutex_unlock(mutex)                                          \
 173     G_THREAD_CF (mutex_unlock,   (void)0, (mutex))
 174 # define g_mutex_free(mutex)                                            \
 175     G_THREAD_CF (mutex_free,     (void)0, (mutex))
 176 # define g_cond_wait(cond, mutex)                                       \
 177     G_THREAD_CF (cond_wait,      (void)0, (cond, mutex))
 178 # define g_cond_timed_wait(cond, mutex, abs_time)                       \
 179     G_THREAD_CF (cond_timed_wait, TRUE,   (cond, mutex, abs_time))
 180 #else /* G_ERRORCHECK_MUTEXES */
 181 # define g_mutex_lock(mutex)                                            \
 182     G_THREAD_ECF (mutex_lock,    (void)0, (mutex), void)
 183 # define g_mutex_trylock(mutex)                                         \
 184     G_THREAD_ECF (mutex_trylock, TRUE,    (mutex), gboolean)
 185 # define g_mutex_unlock(mutex)                                          \
 186     G_THREAD_ECF (mutex_unlock,  (void)0, (mutex), void)
 187 # define g_mutex_free(mutex)                                            \
 188     G_THREAD_ECF (mutex_free,    (void)0, (mutex), void)
 189 # define g_cond_wait(cond, mutex)                                       \
 190     (g_thread_supported () ? ((void(*)(GCond*, GMutex*, gulong, gchar*))\
 191       g_thread_functions_for_glib_use.cond_wait)                        \
 192         (cond, mutex, G_MUTEX_DEBUG_MAGIC, G_STRLOC) : (void) 0)
 193 # define g_cond_timed_wait(cond, mutex, abs_time)                       \
 194     (g_thread_supported () ?                                            \
 195       ((gboolean(*)(GCond*, GMutex*, GTimeVal*, gulong, gchar*))        \
 196         g_thread_functions_for_glib_use.cond_timed_wait)                \
 197           (cond, mutex, abs_time, G_MUTEX_DEBUG_MAGIC, G_STRLOC) : TRUE)
 198 #endif /* G_ERRORCHECK_MUTEXES */
 199
 200 #if defined(G_THREADS_ENABLED) && defined(G_THREADS_MANDATORY)
 201 #define g_thread_supported()     1
 202 #else
 203 #define g_thread_supported()    (g_threads_got_initialized)
 204 #endif
 205 #define g_mutex_new()            G_THREAD_UF (mutex_new,      ())
 206 #define g_cond_new()             G_THREAD_UF (cond_new,       ())
 207 #define g_cond_signal(cond)      G_THREAD_CF (cond_signal,    (void)0, (cond))
 208 #define g_cond_broadcast(cond)   G_THREAD_CF (cond_broadcast, (void)0, (cond))
 209 #define g_cond_free(cond)        G_THREAD_CF (cond_free,      (void)0, (cond))
 210 #define g_private_new(destructor) G_THREAD_UF (private_new, (destructor))
 211 #define g_private_get(private_key) G_THREAD_CF (private_get, \
 212                                                 ((gpointer)private_key), \
 213                                                 (private_key))
 214 #define g_private_set(private_key, value) G_THREAD_CF (private_set, \
 215                                                        (void) (private_key = \
 216                                                         (GPrivate*) (value)), \
 217                                                        (private_key, value))
 218 #define g_thread_yield()              G_THREAD_CF (thread_yield, (void)0, ())
 219
 220 #define g_thread_create(func, data, joinable, error)                    \
 221   (g_thread_create_full (func, data, 0, joinable, FALSE,                \
 222                          G_THREAD_PRIORITY_NORMAL, error))
 223
 224 GThread* g_thread_create_full  (GThreadFunc            func,
 225                                 gpointer               data,
 226                                 gulong                 stack_size,
 227                                 gboolean               joinable,
 228                                 gboolean               bound,
 229                                 GThreadPriority        priority,
 230                                 GError               **error);
 231 GThread* g_thread_self         (void);
 232 void     g_thread_exit         (gpointer               retval);
 233 gpointer g_thread_join         (GThread               *thread);
 234
 235 void     g_thread_set_priority (GThread               *thread,
 236                                 GThreadPriority        priority);
 237
 238 /* GStaticMutexes can be statically initialized with the value
 239  * G_STATIC_MUTEX_INIT, and then they can directly be used, that is
 240  * much easier, than having to explicitly allocate the mutex before
 241  * use
 242  */
 243 #define g_static_mutex_lock(mutex) \
 244     g_mutex_lock (g_static_mutex_get_mutex (mutex))
 245 #define g_static_mutex_trylock(mutex) \
 246     g_mutex_trylock (g_static_mutex_get_mutex (mutex))
 247 #define g_static_mutex_unlock(mutex) \
 248     g_mutex_unlock (g_static_mutex_get_mutex (mutex))
 249 void g_static_mutex_init (GStaticMutex *mutex);
 250 void g_static_mutex_free (GStaticMutex *mutex);
 251
 252 struct _GStaticPrivate
 253 {
 254   /*< private >*/
 255   guint index;
 256 };
 257 #define G_STATIC_PRIVATE_INIT { 0 }
 258 void     g_static_private_init           (GStaticPrivate   *private_key);
 259 gpointer g_static_private_get            (GStaticPrivate   *private_key);
 260 void     g_static_private_set            (GStaticPrivate   *private_key,
 261                                           gpointer          data,
 262                                           GDestroyNotify    notify);
 263 void     g_static_private_free           (GStaticPrivate   *private_key);
 264
 265 typedef struct _GStaticRecMutex GStaticRecMutex;
 266 struct _GStaticRecMutex
 267 {
 268   /*< private >*/
 269   GStaticMutex mutex;
 270   guint depth;
 271   GSystemThread owner;
 272 };
 273
 274 #define G_STATIC_REC_MUTEX_INIT { G_STATIC_MUTEX_INIT, 0 }
 275 void     g_static_rec_mutex_init        (GStaticRecMutex *mutex);
 276 void     g_static_rec_mutex_lock        (GStaticRecMutex *mutex);
 277 gboolean g_static_rec_mutex_trylock     (GStaticRecMutex *mutex);
 278 void     g_static_rec_mutex_unlock      (GStaticRecMutex *mutex);
 279 void     g_static_rec_mutex_lock_full   (GStaticRecMutex *mutex,
 280                                          guint            depth);
 281 guint    g_static_rec_mutex_unlock_full (GStaticRecMutex *mutex);
 282 void     g_static_rec_mutex_free        (GStaticRecMutex *mutex);
 283
 284 typedef struct _GStaticRWLock GStaticRWLock;
 285 struct _GStaticRWLock
 286 {
 287   /*< private >*/
 288   GStaticMutex mutex;
 289   GCond *read_cond;
 290   GCond *write_cond;
 291   guint read_counter;
 292   gboolean have_writer;
 293   guint want_to_read;
 294   guint want_to_write;
 295 };
 296
 297 #define G_STATIC_RW_LOCK_INIT { G_STATIC_MUTEX_INIT, NULL, NULL, 0, FALSE, 0, 0 }
 298
 299 void      g_static_rw_lock_init           (GStaticRWLock* lock);
 300 void      g_static_rw_lock_reader_lock    (GStaticRWLock* lock);
 301 gboolean  g_static_rw_lock_reader_trylock (GStaticRWLock* lock);
 302 void      g_static_rw_lock_reader_unlock  (GStaticRWLock* lock);
 303 void      g_static_rw_lock_writer_lock    (GStaticRWLock* lock);
 304 gboolean  g_static_rw_lock_writer_trylock (GStaticRWLock* lock);
 305 void      g_static_rw_lock_writer_unlock  (GStaticRWLock* lock);
 306 void      g_static_rw_lock_free           (GStaticRWLock* lock);
 307
 308 void      g_thread_foreach                (GFunc          thread_func,
 309                                            gpointer       user_data);
 310
 311 typedef enum
 312 {
 313   G_ONCE_STATUS_NOTCALLED,
 314   G_ONCE_STATUS_PROGRESS,
 315   G_ONCE_STATUS_READY
 316 } GOnceStatus;
 317
 318 typedef struct _GOnce GOnce;
 319 struct _GOnce
 320 {
 321   volatile GOnceStatus status;
 322   volatile gpointer retval;
 323 };
 324
 325 #define G_ONCE_INIT { G_ONCE_STATUS_NOTCALLED, NULL }
 326
 327 gpointer g_once_impl (GOnce *once, GThreadFunc func, gpointer arg);
 328
 329 #ifdef G_ATOMIC_OP_MEMORY_BARRIER_NEEDED
 330 # define g_once(once, func, arg) g_once_impl ((once), (func), (arg))
 331 #else /* !G_ATOMIC_OP_MEMORY_BARRIER_NEEDED*/
 332 # define g_once(once, func, arg) \
 333   (((once)->status == G_ONCE_STATUS_READY) ? \
 334    (once)->retval : \
 335    g_once_impl ((once), (func), (arg)))
 336 #endif /* G_ATOMIC_OP_MEMORY_BARRIER_NEEDED */
 337
 338 /* initialize-once guards, keyed by value_location */
 339 G_INLINE_FUNC gboolean  g_once_init_enter       (volatile gsize *value_location);
 340 gboolean                g_once_init_enter_impl  (volatile gsize *value_location);
 341 void                    g_once_init_leave       (volatile gsize *value_location,
 342                                                  gsize           initialization_value);
 343 #if defined (G_CAN_INLINE) || defined (__G_THREAD_C__)
 344 G_INLINE_FUNC gboolean
 345 g_once_init_enter (volatile gsize *value_location)
 346 {
 347   if G_LIKELY ((gpointer) g_atomic_pointer_get (value_location) != NULL)
 348     return FALSE;
 349   else
 350     return g_once_init_enter_impl (value_location);
 351 }
 352 #endif /* G_CAN_INLINE || __G_THREAD_C__ */
 353
 354 /* these are some convenience macros that expand to nothing if GLib
 355  * was configured with --disable-threads. for using StaticMutexes,
 356  * you define them with G_LOCK_DEFINE_STATIC (name) or G_LOCK_DEFINE (name)
 357  * if you need to export the mutex. With G_LOCK_EXTERN (name) you can
 358  * declare such an globally defined lock. name is a unique identifier
 359  * for the protected varibale or code portion. locking, testing and
 360  * unlocking of such mutexes can be done with G_LOCK(), G_UNLOCK() and
 361  * G_TRYLOCK() respectively.
 362  */
 363 extern void glib_dummy_decl (void);
 364 #define G_LOCK_NAME(name)               g__ ## name ## _lock
 365 #ifdef  G_THREADS_ENABLED
 366 #  define G_LOCK_DEFINE_STATIC(name)    static G_LOCK_DEFINE (name)
 367 #  define G_LOCK_DEFINE(name)           \
 368     GStaticMutex G_LOCK_NAME (name) = G_STATIC_MUTEX_INIT
 369 #  define G_LOCK_EXTERN(name)           extern GStaticMutex G_LOCK_NAME (name)
 370
 371 #  ifdef G_DEBUG_LOCKS
 372 #    define G_LOCK(name)                G_STMT_START{             \
 373         g_log (G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG,                   \
 374                "file %s: line %d (%s): locking: %s ",             \
 375                __FILE__,        __LINE__, G_STRFUNC,              \
 376                #name);                                            \
 377         g_static_mutex_lock (&G_LOCK_NAME (name));                \
 378      }G_STMT_END
 379 #    define G_UNLOCK(name)              G_STMT_START{             \
 380         g_log (G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG,                   \
 381                "file %s: line %d (%s): unlocking: %s ",           \
 382                __FILE__,        __LINE__, G_STRFUNC,              \
 383                #name);                                            \
 384        g_static_mutex_unlock (&G_LOCK_NAME (name));               \
 385      }G_STMT_END
 386 #    define G_TRYLOCK(name)                                       \
 387         (g_log (G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG,                  \
 388                "file %s: line %d (%s): try locking: %s ",         \
 389                __FILE__,        __LINE__, G_STRFUNC,              \
 390                #name), g_static_mutex_trylock (&G_LOCK_NAME (name)))
 391 #  else  /* !G_DEBUG_LOCKS */
 392 #    define G_LOCK(name) g_static_mutex_lock       (&G_LOCK_NAME (name))
 393 #    define G_UNLOCK(name) g_static_mutex_unlock   (&G_LOCK_NAME (name))
 394 #    define G_TRYLOCK(name) g_static_mutex_trylock (&G_LOCK_NAME (name))
 395 #  endif /* !G_DEBUG_LOCKS */
 396 #else   /* !G_THREADS_ENABLED */
 397 #  define G_LOCK_DEFINE_STATIC(name)    extern void glib_dummy_decl (void)
 398 #  define G_LOCK_DEFINE(name)           extern void glib_dummy_decl (void)
 399 #  define G_LOCK_EXTERN(name)           extern void glib_dummy_decl (void)
 400 #  define G_LOCK(name)
 401 #  define G_UNLOCK(name)
 402 #  define G_TRYLOCK(name)               (TRUE)
 403 #endif  /* !G_THREADS_ENABLED */
 404
 405 G_END_DECLS
 406
 407 #endif /* __G_THREAD_H__ */