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