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_CAN_INLINE */
  33 #include <glib/gatomic.h>  /* for G_ATOMIC_MEMORY_BARRIER */
  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 /* initializes the mutex/cond/private implementation for glib, might
 117  * only be called once, and must not be called directly or indirectly
 118  * from another glib-function, e.g. as a callback.
 119  */
 120 void    g_thread_init   (GThreadFunctions       *vtable);
 121
 122 /* Errorcheck mutexes. If you define G_ERRORCHECK_MUTEXES, then all
 123  * mutexes will check for re-locking and re-unlocking */
 124
 125 /* Initialize thread system with errorcheck mutexes. vtable must be
 126  * NULL. Do not call directly. Use #define G_ERRORCHECK_MUTEXES
 127  * instead.
 128  */
 129 void    g_thread_init_with_errorcheck_mutexes (GThreadFunctions* vtable);
 130
 131 /* A random number to recognize debug calls to g_mutex_... */
 132 #define G_MUTEX_DEBUG_MAGIC 0xf8e18ad7
 133
 134 #ifdef G_ERRORCHECK_MUTEXES
 135 #define g_thread_init(vtable) g_thread_init_with_errorcheck_mutexes (vtable)
 136 #endif
 137
 138 /* internal function for fallback static mutex implementation */
 139 GMutex* g_static_mutex_get_mutex_impl   (GMutex **mutex);
 140
 141 /* shorthands for conditional and unconditional function calls */
 142
 143 #define G_THREAD_UF(op, arglist)                                        \
 144     (*g_thread_functions_for_glib_use . op) arglist
 145 #define G_THREAD_CF(op, fail, arg)                                      \
 146     (g_thread_supported () ? G_THREAD_UF (op, arg) : (fail))
 147 #define G_THREAD_ECF(op, fail, mutex, type)                             \
 148     (g_thread_supported () ? ((type(*)(GMutex*, gulong, gchar*))        \
 149       (*g_thread_functions_for_glib_use . op))                          \
 150      (mutex, G_MUTEX_DEBUG_MAGIC, G_STRLOC) : (fail))
 151
 152 #ifndef G_ERRORCHECK_MUTEXES
 153 # define g_mutex_lock(mutex)                                            \
 154     G_THREAD_CF (mutex_lock,     (void)0, (mutex))
 155 # define g_mutex_trylock(mutex)                                         \
 156     G_THREAD_CF (mutex_trylock,  TRUE,    (mutex))
 157 # define g_mutex_unlock(mutex)                                          \
 158     G_THREAD_CF (mutex_unlock,   (void)0, (mutex))
 159 # define g_mutex_free(mutex)                                            \
 160     G_THREAD_CF (mutex_free,     (void)0, (mutex))
 161 # define g_cond_wait(cond, mutex)                                       \
 162     G_THREAD_CF (cond_wait,      (void)0, (cond, mutex))
 163 # define g_cond_timed_wait(cond, mutex, abs_time)                       \
 164     G_THREAD_CF (cond_timed_wait, TRUE,   (cond, mutex, abs_time))
 165 #else /* G_ERRORCHECK_MUTEXES */
 166 # define g_mutex_lock(mutex)                                            \
 167     G_THREAD_ECF (mutex_lock,    (void)0, (mutex), void)
 168 # define g_mutex_trylock(mutex)                                         \
 169     G_THREAD_ECF (mutex_trylock, TRUE,    (mutex), gboolean)
 170 # define g_mutex_unlock(mutex)                                          \
 171     G_THREAD_ECF (mutex_unlock,  (void)0, (mutex), void)
 172 # define g_mutex_free(mutex)                                            \
 173     G_THREAD_ECF (mutex_free,    (void)0, (mutex), void)
 174 # define g_cond_wait(cond, mutex)                                       \
 175     (g_thread_supported () ? ((void(*)(GCond*, GMutex*, gulong, gchar*))\
 176       g_thread_functions_for_glib_use.cond_wait)                        \
 177         (cond, mutex, G_MUTEX_DEBUG_MAGIC, G_STRLOC) : (void) 0)
 178 # define g_cond_timed_wait(cond, mutex, abs_time)                       \
 179     (g_thread_supported () ?                                            \
 180       ((gboolean(*)(GCond*, GMutex*, GTimeVal*, gulong, gchar*))        \
 181         g_thread_functions_for_glib_use.cond_timed_wait)                \
 182           (cond, mutex, abs_time, G_MUTEX_DEBUG_MAGIC, G_STRLOC) : TRUE)
 183 #endif /* G_ERRORCHECK_MUTEXES */
 184
 185 #define g_thread_supported()    (g_threads_got_initialized)
 186 #define g_mutex_new()            G_THREAD_UF (mutex_new,      ())
 187 #define g_cond_new()             G_THREAD_UF (cond_new,       ())
 188 #define g_cond_signal(cond)      G_THREAD_CF (cond_signal,    (void)0, (cond))
 189 #define g_cond_broadcast(cond)   G_THREAD_CF (cond_broadcast, (void)0, (cond))
 190 #define g_cond_free(cond)        G_THREAD_CF (cond_free,      (void)0, (cond))
 191 #define g_private_new(destructor) G_THREAD_UF (private_new, (destructor))
 192 #define g_private_get(private_key) G_THREAD_CF (private_get, \
 193                                                 ((gpointer)private_key), \
 194                                                 (private_key))
 195 #define g_private_set(private_key, value) G_THREAD_CF (private_set, \
 196                                                        (void) (private_key = \
 197                                                         (GPrivate*) (value)), \
 198                                                        (private_key, value))
 199 #define g_thread_yield()              G_THREAD_CF (thread_yield, (void)0, ())
 200
 201 #define g_thread_create(func, data, joinable, error)                    \
 202   (g_thread_create_full (func, data, 0, joinable, FALSE,                \
 203                          G_THREAD_PRIORITY_NORMAL, error))
 204
 205 GThread* g_thread_create_full  (GThreadFunc            func,
 206                                 gpointer               data,
 207                                 gulong                 stack_size,
 208                                 gboolean               joinable,
 209                                 gboolean               bound,
 210                                 GThreadPriority        priority,
 211                                 GError               **error);
 212 GThread* g_thread_self         (void);
 213 void     g_thread_exit         (gpointer               retval);
 214 gpointer g_thread_join         (GThread               *thread);
 215
 216 void     g_thread_set_priority (GThread               *thread,
 217                                 GThreadPriority        priority);
 218
 219 /* GStaticMutexes can be statically initialized with the value
 220  * G_STATIC_MUTEX_INIT, and then they can directly be used, that is
 221  * much easier, than having to explicitly allocate the mutex before
 222  * use
 223  */
 224 #define g_static_mutex_lock(mutex) \
 225     g_mutex_lock (g_static_mutex_get_mutex (mutex))
 226 #define g_static_mutex_trylock(mutex) \
 227     g_mutex_trylock (g_static_mutex_get_mutex (mutex))
 228 #define g_static_mutex_unlock(mutex) \
 229     g_mutex_unlock (g_static_mutex_get_mutex (mutex))
 230 void g_static_mutex_init (GStaticMutex *mutex);
 231 void g_static_mutex_free (GStaticMutex *mutex);
 232
 233 struct _GStaticPrivate
 234 {
 235   /*< private >*/
 236   guint index;
 237 };
 238 #define G_STATIC_PRIVATE_INIT { 0 }
 239 void     g_static_private_init           (GStaticPrivate   *private_key);
 240 gpointer g_static_private_get            (GStaticPrivate   *private_key);
 241 void     g_static_private_set            (GStaticPrivate   *private_key,
 242                                           gpointer          data,
 243                                           GDestroyNotify    notify);
 244 void     g_static_private_free           (GStaticPrivate   *private_key);
 245
 246 typedef struct _GStaticRecMutex GStaticRecMutex;
 247 struct _GStaticRecMutex
 248 {
 249   /*< private >*/
 250   GStaticMutex mutex;
 251   guint depth;
 252   GSystemThread owner;
 253 };
 254
 255 #define G_STATIC_REC_MUTEX_INIT { G_STATIC_MUTEX_INIT }
 256 void     g_static_rec_mutex_init        (GStaticRecMutex *mutex);
 257 void     g_static_rec_mutex_lock        (GStaticRecMutex *mutex);
 258 gboolean g_static_rec_mutex_trylock     (GStaticRecMutex *mutex);
 259 void     g_static_rec_mutex_unlock      (GStaticRecMutex *mutex);
 260 void     g_static_rec_mutex_lock_full   (GStaticRecMutex *mutex,
 261                                          guint            depth);
 262 guint    g_static_rec_mutex_unlock_full (GStaticRecMutex *mutex);
 263 void     g_static_rec_mutex_free        (GStaticRecMutex *mutex);
 264
 265 typedef struct _GStaticRWLock GStaticRWLock;
 266 struct _GStaticRWLock
 267 {
 268   /*< private >*/
 269   GStaticMutex mutex;
 270   GCond *read_cond;
 271   GCond *write_cond;
 272   guint read_counter;
 273   gboolean have_writer;
 274   guint want_to_read;
 275   guint want_to_write;
 276 };
 277
 278 #define G_STATIC_RW_LOCK_INIT { G_STATIC_MUTEX_INIT, NULL, NULL, 0, FALSE, 0, 0 }
 279
 280 void      g_static_rw_lock_init           (GStaticRWLock* lock);
 281 void      g_static_rw_lock_reader_lock    (GStaticRWLock* lock);
 282 gboolean  g_static_rw_lock_reader_trylock (GStaticRWLock* lock);
 283 void      g_static_rw_lock_reader_unlock  (GStaticRWLock* lock);
 284 void      g_static_rw_lock_writer_lock    (GStaticRWLock* lock);
 285 gboolean  g_static_rw_lock_writer_trylock (GStaticRWLock* lock);
 286 void      g_static_rw_lock_writer_unlock  (GStaticRWLock* lock);
 287 void      g_static_rw_lock_free           (GStaticRWLock* lock);
 288
 289 typedef enum
 290 {
 291   G_ONCE_STATUS_NOTCALLED,
 292   G_ONCE_STATUS_PROGRESS,
 293   G_ONCE_STATUS_READY
 294 } GOnceStatus;
 295
 296 typedef struct _GOnce GOnce;
 297 struct _GOnce
 298 {
 299   volatile GOnceStatus status;
 300   volatile gpointer retval;
 301 };
 302
 303 #define G_ONCE_INIT { G_ONCE_STATUS_NOTCALLED, NULL }
 304
 305 gpointer g_once_impl (GOnce *once, GThreadFunc func, gpointer arg);
 306
 307 #if defined (G_CAN_INLINE) && defined (G_ATOMIC_MEMORY_BARRIER)
 308 static inline gpointer
 309 g_once (GOnce *once, GThreadFunc func, gpointer arg)
 310 {
 311   if (once->status != G_ONCE_STATUS_READY)
 312     return g_once_impl (once, func, arg);
 313
 314   G_ATOMIC_MEMORY_BARRIER ();
 315   return once->retval;
 316 }
 317 static inline GMutex*
 318 g_static_mutex_get_mutex_impl_shortcut (GMutex **mutex)
 319 {
 320   if (! *mutex)
 321     return g_static_mutex_get_mutex_impl (mutex);
 322
 323   G_ATOMIC_MEMORY_BARRIER ();
 324   return *mutex;
 325 }
 326 #else /* !G_CAN_INLINE || !G_ATOMIC_MEMORY_BARRIER */
 327 # define g_once g_once_impl
 328 # define g_static_mutex_get_mutex_impl_shortcut g_static_mutex_get_mutex_impl
 329 #endif /* G_CAN_INLINE && G_ATOMIC_MEMORY_BARRIER*/
 330
 331 /* these are some convenience macros that expand to nothing if GLib
 332  * was configured with --disable-threads. for using StaticMutexes,
 333  * you define them with G_LOCK_DEFINE_STATIC (name) or G_LOCK_DEFINE (name)
 334  * if you need to export the mutex. With G_LOCK_EXTERN (name) you can
 335  * declare such an globally defined lock. name is a unique identifier
 336  * for the protected varibale or code portion. locking, testing and
 337  * unlocking of such mutexes can be done with G_LOCK(), G_UNLOCK() and
 338  * G_TRYLOCK() respectively.
 339  */
 340 extern void glib_dummy_decl (void);
 341 #define G_LOCK_NAME(name)               g__ ## name ## _lock
 342 #ifdef  G_THREADS_ENABLED
 343 #  define G_LOCK_DEFINE_STATIC(name)    static G_LOCK_DEFINE (name)
 344 #  define G_LOCK_DEFINE(name)           \
 345     GStaticMutex G_LOCK_NAME (name) = G_STATIC_MUTEX_INIT
 346 #  define G_LOCK_EXTERN(name)           extern GStaticMutex G_LOCK_NAME (name)
 347
 348 #  ifdef G_DEBUG_LOCKS
 349 #    define G_LOCK(name)                G_STMT_START{             \
 350         g_log (G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG,                   \
 351                "file %s: line %d (%s): locking: %s ",             \
 352                __FILE__,        __LINE__, G_GNUC_PRETTY_FUNCTION, \
 353                #name);                                            \
 354         g_static_mutex_lock (&G_LOCK_NAME (name));                \
 355      }G_STMT_END
 356 #    define G_UNLOCK(name)              G_STMT_START{             \
 357         g_log (G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG,                   \
 358                "file %s: line %d (%s): unlocking: %s ",           \
 359                __FILE__,        __LINE__, G_GNUC_PRETTY_FUNCTION, \
 360                #name);                                            \
 361        g_static_mutex_unlock (&G_LOCK_NAME (name));               \
 362      }G_STMT_END
 363 #    define G_TRYLOCK(name)                                       \
 364         (g_log (G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG,                  \
 365                "file %s: line %d (%s): try locking: %s ",         \
 366                __FILE__,        __LINE__, G_GNUC_PRETTY_FUNCTION, \
 367                #name), g_static_mutex_trylock (&G_LOCK_NAME (name)))
 368 #  else  /* !G_DEBUG_LOCKS */
 369 #    define G_LOCK(name) g_static_mutex_lock       (&G_LOCK_NAME (name))
 370 #    define G_UNLOCK(name) g_static_mutex_unlock   (&G_LOCK_NAME (name))
 371 #    define G_TRYLOCK(name) g_static_mutex_trylock (&G_LOCK_NAME (name))
 372 #  endif /* !G_DEBUG_LOCKS */
 373 #else   /* !G_THREADS_ENABLED */
 374 #  define G_LOCK_DEFINE_STATIC(name)    extern void glib_dummy_decl (void)
 375 #  define G_LOCK_DEFINE(name)           extern void glib_dummy_decl (void)
 376 #  define G_LOCK_EXTERN(name)           extern void glib_dummy_decl (void)
 377 #  define G_LOCK(name)
 378 #  define G_UNLOCK(name)
 379 #  define G_TRYLOCK(name)               (TRUE)
 380 #endif  /* !G_THREADS_ENABLED */
 381
 382 G_END_DECLS
 383
 384 #endif /* __G_THREAD_H__ */
 385