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