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 #ifndef G_DISABLE_DEPRECATED
 120 GLIB_VAR guint64   (*g_thread_gettime) (void);
 121 #endif
 122
 123 /* initializes the mutex/cond/private implementation for glib, might
 124  * only be called once, and must not be called directly or indirectly
 125  * from another glib-function, e.g. as a callback.
 126  */
 127 void    g_thread_init   (GThreadFunctions       *vtable);
 128
 129 /* Checks if thread support is initialized.  Identical to the
 130  * g_thread_supported macro but provided for language bindings.
 131  */
 132 gboolean g_thread_get_initialized (void);
 133
 134 /* A random number to recognize debug calls to g_mutex_... */
 135 #define G_MUTEX_DEBUG_MAGIC 0xf8e18ad7
 136
 137 /* internal function for fallback static mutex implementation */
 138 GMutex* g_static_mutex_get_mutex_impl   (GMutex **mutex);
 139
 140 #define g_static_mutex_get_mutex_impl_shortcut(mutex) \
 141   (g_atomic_pointer_get (mutex) ? *(mutex) : \
 142    g_static_mutex_get_mutex_impl (mutex))
 143
 144 /* shorthands for conditional and unconditional function calls */
 145
 146 #define G_THREAD_UF(op, arglist)                                        \
 147     (*g_thread_functions_for_glib_use . op) arglist
 148 #define G_THREAD_CF(op, fail, arg)                                      \
 149     (g_thread_supported () ? G_THREAD_UF (op, arg) : (fail))
 150 #define G_THREAD_ECF(op, fail, mutex, type)                             \
 151     (g_thread_supported () ?                                            \
 152       ((type(*)(GMutex*, const gulong, gchar const*))                   \
 153       (*g_thread_functions_for_glib_use . op))                          \
 154      (mutex, G_MUTEX_DEBUG_MAGIC, G_STRLOC) : (fail))
 155
 156 #ifndef G_ERRORCHECK_MUTEXES
 157 # define g_mutex_lock(mutex)                                            \
 158     G_THREAD_CF (mutex_lock,     (void)0, (mutex))
 159 # define g_mutex_trylock(mutex)                                         \
 160     G_THREAD_CF (mutex_trylock,  TRUE,    (mutex))
 161 # define g_mutex_unlock(mutex)                                          \
 162     G_THREAD_CF (mutex_unlock,   (void)0, (mutex))
 163 # define g_mutex_free(mutex)                                            \
 164     G_THREAD_CF (mutex_free,     (void)0, (mutex))
 165 # define g_cond_wait(cond, mutex)                                       \
 166     G_THREAD_CF (cond_wait,      (void)0, (cond, mutex))
 167 # define g_cond_timed_wait(cond, mutex, abs_time)                       \
 168     G_THREAD_CF (cond_timed_wait, TRUE,   (cond, mutex, abs_time))
 169 #else /* G_ERRORCHECK_MUTEXES */
 170 # define g_mutex_lock(mutex)                                            \
 171     G_THREAD_ECF (mutex_lock,    (void)0, (mutex), void)
 172 # define g_mutex_trylock(mutex)                                         \
 173     G_THREAD_ECF (mutex_trylock, TRUE,    (mutex), gboolean)
 174 # define g_mutex_unlock(mutex)                                          \
 175     G_THREAD_ECF (mutex_unlock,  (void)0, (mutex), void)
 176 # define g_mutex_free(mutex)                                            \
 177     G_THREAD_ECF (mutex_free,    (void)0, (mutex), void)
 178 # define g_cond_wait(cond, mutex)                                       \
 179     (g_thread_supported () ? ((void(*)(GCond*, GMutex*, gulong, gchar*))\
 180       g_thread_functions_for_glib_use.cond_wait)                        \
 181         (cond, mutex, G_MUTEX_DEBUG_MAGIC, G_STRLOC) : (void) 0)
 182 # define g_cond_timed_wait(cond, mutex, abs_time)                       \
 183     (g_thread_supported () ?                                            \
 184       ((gboolean(*)(GCond*, GMutex*, GTimeVal*, gulong, gchar*))        \
 185         g_thread_functions_for_glib_use.cond_timed_wait)                \
 186           (cond, mutex, abs_time, G_MUTEX_DEBUG_MAGIC, G_STRLOC) : TRUE)
 187 #endif /* G_ERRORCHECK_MUTEXES */
 188
 189 #if defined(G_THREADS_MANDATORY)
 190 #define g_thread_supported()     1
 191 #else
 192 #define g_thread_supported()    (g_threads_got_initialized)
 193 #endif
 194 #define g_mutex_new()            G_THREAD_UF (mutex_new,      ())
 195 #define g_cond_new()             G_THREAD_UF (cond_new,       ())
 196 #define g_cond_signal(cond)      G_THREAD_CF (cond_signal,    (void)0, (cond))
 197 #define g_cond_broadcast(cond)   G_THREAD_CF (cond_broadcast, (void)0, (cond))
 198 #define g_cond_free(cond)        G_THREAD_CF (cond_free,      (void)0, (cond))
 199 #define g_private_new(destructor) G_THREAD_UF (private_new, (destructor))
 200 #define g_private_get(private_key) G_THREAD_CF (private_get, \
 201                                                 ((gpointer)private_key), \
 202                                                 (private_key))
 203 #define g_private_set(private_key, value) G_THREAD_CF (private_set, \
 204                                                        (void) (private_key = \
 205                                                         (GPrivate*) (value)), \
 206                                                        (private_key, value))
 207 #define g_thread_yield()              G_THREAD_CF (thread_yield, (void)0, ())
 208
 209 #define g_thread_create(func, data, joinable, error)                    \
 210   (g_thread_create_full (func, data, 0, joinable, FALSE,                \
 211                          G_THREAD_PRIORITY_NORMAL, error))
 212
 213 GThread* g_thread_create_full  (GThreadFunc            func,
 214                                 gpointer               data,
 215                                 gulong                 stack_size,
 216                                 gboolean               joinable,
 217                                 gboolean               bound,
 218                                 GThreadPriority        priority,
 219                                 GError               **error);
 220 GThread* g_thread_self         (void);
 221 void     g_thread_exit         (gpointer               retval);
 222 gpointer g_thread_join         (GThread               *thread);
 223
 224 void     g_thread_set_priority (GThread               *thread,
 225                                 GThreadPriority        priority);
 226
 227 /* GStaticMutexes can be statically initialized with the value
 228  * G_STATIC_MUTEX_INIT, and then they can directly be used, that is
 229  * much easier, than having to explicitly allocate the mutex before
 230  * use
 231  */
 232 #define g_static_mutex_lock(mutex) \
 233     g_mutex_lock (g_static_mutex_get_mutex (mutex))
 234 #define g_static_mutex_trylock(mutex) \
 235     g_mutex_trylock (g_static_mutex_get_mutex (mutex))
 236 #define g_static_mutex_unlock(mutex) \
 237     g_mutex_unlock (g_static_mutex_get_mutex (mutex))
 238 void g_static_mutex_init (GStaticMutex *mutex);
 239 void g_static_mutex_free (GStaticMutex *mutex);
 240
 241 struct _GStaticPrivate
 242 {
 243   /*< private >*/
 244   guint index;
 245 };
 246 #define G_STATIC_PRIVATE_INIT { 0 }
 247 void     g_static_private_init           (GStaticPrivate   *private_key);
 248 gpointer g_static_private_get            (GStaticPrivate   *private_key);
 249 void     g_static_private_set            (GStaticPrivate   *private_key,
 250                                           gpointer          data,
 251                                           GDestroyNotify    notify);
 252 void     g_static_private_free           (GStaticPrivate   *private_key);
 253
 254 typedef struct _GStaticRecMutex GStaticRecMutex;
 255 struct _GStaticRecMutex
 256 {
 257   /*< private >*/
 258   GStaticMutex mutex;
 259   guint depth;
 260   GSystemThread owner;
 261 };
 262
 263 #define G_STATIC_REC_MUTEX_INIT { G_STATIC_MUTEX_INIT, 0, {{0, 0, 0, 0}} }
 264 void     g_static_rec_mutex_init        (GStaticRecMutex *mutex);
 265 void     g_static_rec_mutex_lock        (GStaticRecMutex *mutex);
 266 gboolean g_static_rec_mutex_trylock     (GStaticRecMutex *mutex);
 267 void     g_static_rec_mutex_unlock      (GStaticRecMutex *mutex);
 268 void     g_static_rec_mutex_lock_full   (GStaticRecMutex *mutex,
 269                                          guint            depth);
 270 guint    g_static_rec_mutex_unlock_full (GStaticRecMutex *mutex);
 271 void     g_static_rec_mutex_free        (GStaticRecMutex *mutex);
 272
 273 typedef struct _GStaticRWLock GStaticRWLock;
 274 struct _GStaticRWLock
 275 {
 276   /*< private >*/
 277   GStaticMutex mutex;
 278   GCond *read_cond;
 279   GCond *write_cond;
 280   guint read_counter;
 281   gboolean have_writer;
 282   guint want_to_read;
 283   guint want_to_write;
 284 };
 285
 286 #define G_STATIC_RW_LOCK_INIT { G_STATIC_MUTEX_INIT, NULL, NULL, 0, FALSE, 0, 0 }
 287
 288 void      g_static_rw_lock_init           (GStaticRWLock* lock);
 289 void      g_static_rw_lock_reader_lock    (GStaticRWLock* lock);
 290 gboolean  g_static_rw_lock_reader_trylock (GStaticRWLock* lock);
 291 void      g_static_rw_lock_reader_unlock  (GStaticRWLock* lock);
 292 void      g_static_rw_lock_writer_lock    (GStaticRWLock* lock);
 293 gboolean  g_static_rw_lock_writer_trylock (GStaticRWLock* lock);
 294 void      g_static_rw_lock_writer_unlock  (GStaticRWLock* lock);
 295 void      g_static_rw_lock_free           (GStaticRWLock* lock);
 296
 297 void      g_thread_foreach                (GFunc          thread_func,
 298                                            gpointer       user_data);
 299
 300 typedef enum
 301 {
 302   G_ONCE_STATUS_NOTCALLED,
 303   G_ONCE_STATUS_PROGRESS,
 304   G_ONCE_STATUS_READY
 305 } GOnceStatus;
 306
 307 typedef struct _GOnce GOnce;
 308 struct _GOnce
 309 {
 310   volatile GOnceStatus status;
 311   volatile gpointer retval;
 312 };
 313
 314 #define G_ONCE_INIT { G_ONCE_STATUS_NOTCALLED, NULL }
 315
 316 gpointer g_once_impl (GOnce *once, GThreadFunc func, gpointer arg);
 317
 318 #ifdef G_ATOMIC_OP_MEMORY_BARRIER_NEEDED
 319 # define g_once(once, func, arg) g_once_impl ((once), (func), (arg))
 320 #else /* !G_ATOMIC_OP_MEMORY_BARRIER_NEEDED*/
 321 # define g_once(once, func, arg) \
 322   (((once)->status == G_ONCE_STATUS_READY) ? \
 323    (once)->retval : \
 324    g_once_impl ((once), (func), (arg)))
 325 #endif /* G_ATOMIC_OP_MEMORY_BARRIER_NEEDED */
 326
 327 /* initialize-once guards, keyed by value_location */
 328 G_INLINE_FUNC gboolean  g_once_init_enter       (volatile gsize *value_location);
 329 gboolean                g_once_init_enter_impl  (volatile gsize *value_location);
 330 void                    g_once_init_leave       (volatile gsize *value_location,
 331                                                  gsize           initialization_value);
 332 #if defined (G_CAN_INLINE) || defined (__G_THREAD_C__)
 333 G_INLINE_FUNC gboolean
 334 g_once_init_enter (volatile gsize *value_location)
 335 {
 336   if G_LIKELY ((gpointer) g_atomic_pointer_get (value_location) != NULL)
 337     return FALSE;
 338   else
 339     return g_once_init_enter_impl (value_location);
 340 }
 341 #endif /* G_CAN_INLINE || __G_THREAD_C__ */
 342
 343 /* these are some convenience macros that expand to nothing if GLib
 344  * was configured with --disable-threads. for using StaticMutexes,
 345  * you define them with G_LOCK_DEFINE_STATIC (name) or G_LOCK_DEFINE (name)
 346  * if you need to export the mutex. With G_LOCK_EXTERN (name) you can
 347  * declare such an globally defined lock. name is a unique identifier
 348  * for the protected varibale or code portion. locking, testing and
 349  * unlocking of such mutexes can be done with G_LOCK(), G_UNLOCK() and
 350  * G_TRYLOCK() respectively.
 351  */
 352 extern void glib_dummy_decl (void);
 353 #define G_LOCK_NAME(name)               g__ ## name ## _lock
 354 #define G_LOCK_DEFINE_STATIC(name)    static G_LOCK_DEFINE (name)
 355 #define G_LOCK_DEFINE(name)           \
 356   GStaticMutex G_LOCK_NAME (name) = G_STATIC_MUTEX_INIT
 357 #define G_LOCK_EXTERN(name)           extern GStaticMutex G_LOCK_NAME (name)
 358
 359 #ifdef G_DEBUG_LOCKS
 360 #  define G_LOCK(name)                G_STMT_START{             \
 361       g_log (G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG,                   \
 362              "file %s: line %d (%s): locking: %s ",             \
 363              __FILE__,        __LINE__, G_STRFUNC,              \
 364              #name);                                            \
 365       g_static_mutex_lock (&G_LOCK_NAME (name));                \
 366    }G_STMT_END
 367 #  define G_UNLOCK(name)              G_STMT_START{             \
 368       g_log (G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG,                   \
 369              "file %s: line %d (%s): unlocking: %s ",           \
 370              __FILE__,        __LINE__, G_STRFUNC,              \
 371              #name);                                            \
 372      g_static_mutex_unlock (&G_LOCK_NAME (name));               \
 373    }G_STMT_END
 374 #  define G_TRYLOCK(name)                                       \
 375       (g_log (G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG,                  \
 376              "file %s: line %d (%s): try locking: %s ",         \
 377              __FILE__,        __LINE__, G_STRFUNC,              \
 378              #name), g_static_mutex_trylock (&G_LOCK_NAME (name)))
 379 #else  /* !G_DEBUG_LOCKS */
 380 #  define G_LOCK(name) g_static_mutex_lock       (&G_LOCK_NAME (name))
 381 #  define G_UNLOCK(name) g_static_mutex_unlock   (&G_LOCK_NAME (name))
 382 #  define G_TRYLOCK(name) g_static_mutex_trylock (&G_LOCK_NAME (name))
 383 #endif /* !G_DEBUG_LOCKS */
 384
 385 G_END_DECLS
 386
 387 #endif /* __G_THREAD_H__ */