Home | History | Annotate | Download | only in glib
      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 #define g_thread_supported()    (g_threads_got_initialized)
    202 #define g_mutex_new()            G_THREAD_UF (mutex_new,      ())
    203 #define g_cond_new()             G_THREAD_UF (cond_new,       ())
    204 #define g_cond_signal(cond)      G_THREAD_CF (cond_signal,    (void)0, (cond))
    205 #define g_cond_broadcast(cond)   G_THREAD_CF (cond_broadcast, (void)0, (cond))
    206 #define g_cond_free(cond)        G_THREAD_CF (cond_free,      (void)0, (cond))
    207 #define g_private_new(destructor) G_THREAD_UF (private_new, (destructor))
    208 #define g_private_get(private_key) G_THREAD_CF (private_get, \
    209                                                 ((gpointer)private_key), \
    210                                                 (private_key))
    211 #define g_private_set(private_key, value) G_THREAD_CF (private_set, \
    212                                                        (void) (private_key = \
    213                                                         (GPrivate*) (value)), \
    214                                                        (private_key, value))
    215 #define g_thread_yield()              G_THREAD_CF (thread_yield, (void)0, ())
    216 
    217 #define g_thread_create(func, data, joinable, error)			\
    218   (g_thread_create_full (func, data, 0, joinable, FALSE, 		\
    219                          G_THREAD_PRIORITY_NORMAL, error))
    220 
    221 GThread* g_thread_create_full  (GThreadFunc            func,
    222                                 gpointer               data,
    223                                 gulong                 stack_size,
    224                                 gboolean               joinable,
    225                                 gboolean               bound,
    226                                 GThreadPriority        priority,
    227                                 GError               **error);
    228 GThread* g_thread_self         (void);
    229 void     g_thread_exit         (gpointer               retval);
    230 gpointer g_thread_join         (GThread               *thread);
    231 
    232 void     g_thread_set_priority (GThread               *thread,
    233                                 GThreadPriority        priority);
    234 
    235 /* GStaticMutexes can be statically initialized with the value
    236  * G_STATIC_MUTEX_INIT, and then they can directly be used, that is
    237  * much easier, than having to explicitly allocate the mutex before
    238  * use
    239  */
    240 #define g_static_mutex_lock(mutex) \
    241     g_mutex_lock (g_static_mutex_get_mutex (mutex))
    242 #define g_static_mutex_trylock(mutex) \
    243     g_mutex_trylock (g_static_mutex_get_mutex (mutex))
    244 #define g_static_mutex_unlock(mutex) \
    245     g_mutex_unlock (g_static_mutex_get_mutex (mutex))
    246 void g_static_mutex_init (GStaticMutex *mutex);
    247 void g_static_mutex_free (GStaticMutex *mutex);
    248 
    249 struct _GStaticPrivate
    250 {
    251   /*< private >*/
    252   guint index;
    253 };
    254 #define G_STATIC_PRIVATE_INIT { 0 }
    255 void     g_static_private_init           (GStaticPrivate   *private_key);
    256 gpointer g_static_private_get            (GStaticPrivate   *private_key);
    257 void     g_static_private_set            (GStaticPrivate   *private_key,
    258 					  gpointer          data,
    259 					  GDestroyNotify    notify);
    260 void     g_static_private_free           (GStaticPrivate   *private_key);
    261 
    262 typedef struct _GStaticRecMutex GStaticRecMutex;
    263 struct _GStaticRecMutex
    264 {
    265   /*< private >*/
    266   GStaticMutex mutex;
    267   guint depth;
    268   GSystemThread owner;
    269 };
    270 
    271 #define G_STATIC_REC_MUTEX_INIT { G_STATIC_MUTEX_INIT }
    272 void     g_static_rec_mutex_init        (GStaticRecMutex *mutex);
    273 void     g_static_rec_mutex_lock        (GStaticRecMutex *mutex);
    274 gboolean g_static_rec_mutex_trylock     (GStaticRecMutex *mutex);
    275 void     g_static_rec_mutex_unlock      (GStaticRecMutex *mutex);
    276 void     g_static_rec_mutex_lock_full   (GStaticRecMutex *mutex,
    277                                          guint            depth);
    278 guint    g_static_rec_mutex_unlock_full (GStaticRecMutex *mutex);
    279 void     g_static_rec_mutex_free        (GStaticRecMutex *mutex);
    280 
    281 typedef struct _GStaticRWLock GStaticRWLock;
    282 struct _GStaticRWLock
    283 {
    284   /*< private >*/
    285   GStaticMutex mutex;
    286   GCond *read_cond;
    287   GCond *write_cond;
    288   guint read_counter;
    289   gboolean have_writer;
    290   guint want_to_read;
    291   guint want_to_write;
    292 };
    293 
    294 #define G_STATIC_RW_LOCK_INIT { G_STATIC_MUTEX_INIT, NULL, NULL, 0, FALSE, 0, 0 }
    295 
    296 void      g_static_rw_lock_init           (GStaticRWLock* lock);
    297 void      g_static_rw_lock_reader_lock    (GStaticRWLock* lock);
    298 gboolean  g_static_rw_lock_reader_trylock (GStaticRWLock* lock);
    299 void      g_static_rw_lock_reader_unlock  (GStaticRWLock* lock);
    300 void      g_static_rw_lock_writer_lock    (GStaticRWLock* lock);
    301 gboolean  g_static_rw_lock_writer_trylock (GStaticRWLock* lock);
    302 void      g_static_rw_lock_writer_unlock  (GStaticRWLock* lock);
    303 void      g_static_rw_lock_free           (GStaticRWLock* lock);
    304 
    305 void	  g_thread_foreach         	  (GFunc    	  thread_func,
    306 					   gpointer 	  user_data);
    307 
    308 typedef enum
    309 {
    310   G_ONCE_STATUS_NOTCALLED,
    311   G_ONCE_STATUS_PROGRESS,
    312   G_ONCE_STATUS_READY
    313 } GOnceStatus;
    314 
    315 typedef struct _GOnce GOnce;
    316 struct _GOnce
    317 {
    318   volatile GOnceStatus status;
    319   volatile gpointer retval;
    320 };
    321 
    322 #define G_ONCE_INIT { G_ONCE_STATUS_NOTCALLED, NULL }
    323 
    324 gpointer g_once_impl (GOnce *once, GThreadFunc func, gpointer arg);
    325 
    326 #ifdef G_ATOMIC_OP_MEMORY_BARRIER_NEEDED
    327 # define g_once(once, func, arg) g_once_impl ((once), (func), (arg))
    328 #else /* !G_ATOMIC_OP_MEMORY_BARRIER_NEEDED*/
    329 # define g_once(once, func, arg) \
    330   (((once)->status == G_ONCE_STATUS_READY) ? \
    331    (once)->retval : \
    332    g_once_impl ((once), (func), (arg)))
    333 #endif /* G_ATOMIC_OP_MEMORY_BARRIER_NEEDED */
    334 
    335 /* initialize-once guards, keyed by value_location */
    336 G_INLINE_FUNC gboolean  g_once_init_enter       (volatile gsize *value_location);
    337 gboolean                g_once_init_enter_impl  (volatile gsize *value_location);
    338 void                    g_once_init_leave       (volatile gsize *value_location,
    339                                                  gsize           initialization_value);
    340 #if defined (G_CAN_INLINE) || defined (__G_THREAD_C__)
    341 G_INLINE_FUNC gboolean
    342 g_once_init_enter (volatile gsize *value_location)
    343 {
    344   if G_LIKELY ((gpointer) g_atomic_pointer_get (value_location) != NULL)
    345     return FALSE;
    346   else
    347     return g_once_init_enter_impl (value_location);
    348 }
    349 #endif /* G_CAN_INLINE || __G_THREAD_C__ */
    350 
    351 /* these are some convenience macros that expand to nothing if GLib
    352  * was configured with --disable-threads. for using StaticMutexes,
    353  * you define them with G_LOCK_DEFINE_STATIC (name) or G_LOCK_DEFINE (name)
    354  * if you need to export the mutex. With G_LOCK_EXTERN (name) you can
    355  * declare such an globally defined lock. name is a unique identifier
    356  * for the protected varibale or code portion. locking, testing and
    357  * unlocking of such mutexes can be done with G_LOCK(), G_UNLOCK() and
    358  * G_TRYLOCK() respectively.
    359  */
    360 extern void glib_dummy_decl (void);
    361 #define G_LOCK_NAME(name)               g__ ## name ## _lock
    362 #ifdef  G_THREADS_ENABLED
    363 #  define G_LOCK_DEFINE_STATIC(name)    static G_LOCK_DEFINE (name)
    364 #  define G_LOCK_DEFINE(name)           \
    365     GStaticMutex G_LOCK_NAME (name) = G_STATIC_MUTEX_INIT
    366 #  define G_LOCK_EXTERN(name)           extern GStaticMutex G_LOCK_NAME (name)
    367 
    368 #  ifdef G_DEBUG_LOCKS
    369 #    define G_LOCK(name)                G_STMT_START{             \
    370         g_log (G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG,                   \
    371                "file %s: line %d (%s): locking: %s ",             \
    372                __FILE__,        __LINE__, G_STRFUNC,              \
    373                #name);                                            \
    374         g_static_mutex_lock (&G_LOCK_NAME (name));                \
    375      }G_STMT_END
    376 #    define G_UNLOCK(name)              G_STMT_START{             \
    377         g_log (G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG,                   \
    378                "file %s: line %d (%s): unlocking: %s ",           \
    379                __FILE__,        __LINE__, G_STRFUNC,              \
    380                #name);                                            \
    381        g_static_mutex_unlock (&G_LOCK_NAME (name));               \
    382      }G_STMT_END
    383 #    define G_TRYLOCK(name)                                       \
    384         (g_log (G_LOG_DOMAIN, G_LOG_LEVEL_DEBUG,                  \
    385                "file %s: line %d (%s): try locking: %s ",         \
    386                __FILE__,        __LINE__, G_STRFUNC,              \
    387                #name), g_static_mutex_trylock (&G_LOCK_NAME (name)))
    388 #  else  /* !G_DEBUG_LOCKS */
    389 #    define G_LOCK(name) g_static_mutex_lock       (&G_LOCK_NAME (name))
    390 #    define G_UNLOCK(name) g_static_mutex_unlock   (&G_LOCK_NAME (name))
    391 #    define G_TRYLOCK(name) g_static_mutex_trylock (&G_LOCK_NAME (name))
    392 #  endif /* !G_DEBUG_LOCKS */
    393 #else   /* !G_THREADS_ENABLED */
    394 #  define G_LOCK_DEFINE_STATIC(name)    extern void glib_dummy_decl (void)
    395 #  define G_LOCK_DEFINE(name)           extern void glib_dummy_decl (void)
    396 #  define G_LOCK_EXTERN(name)           extern void glib_dummy_decl (void)
    397 #  define G_LOCK(name)
    398 #  define G_UNLOCK(name)
    399 #  define G_TRYLOCK(name)               (TRUE)
    400 #endif  /* !G_THREADS_ENABLED */
    401 
    402 G_END_DECLS
    403 
    404 #endif /* __G_THREAD_H__ */
    405