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