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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
g_once_init_enter(volatile gsize * value_location)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