src/semaphore_internal.h

   1 /*
   2  * Copyright (c) 2008-2013 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_APACHE_LICENSE_HEADER_START@
   5  *
   6  * Licensed under the Apache License, Version 2.0 (the "License");
   7  * you may not use this file except in compliance with the License.
   8  * You may obtain a copy of the License at
   9  *
  10  *     http://www.apache.org/licenses/LICENSE-2.0
  11  *
  12  * Unless required by applicable law or agreed to in writing, software
  13  * distributed under the License is distributed on an "AS IS" BASIS,
  14  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  15  * See the License for the specific language governing permissions and
  16  * limitations under the License.
  17  *
  18  * @APPLE_APACHE_LICENSE_HEADER_END@
  19  */
  20
  21 /*
  22  * IMPORTANT: This header file describes INTERNAL interfaces to libdispatch
  23  * which are subject to change in future releases of Mac OS X. Any applications
  24  * relying on these interfaces WILL break.
  25  */
  26
  27 #ifndef __DISPATCH_SEMAPHORE_INTERNAL__
  28 #define __DISPATCH_SEMAPHORE_INTERNAL__
  29
  30 struct dispatch_queue_s;
  31
  32 DISPATCH_CLASS_DECL(semaphore);
  33 struct dispatch_semaphore_s {
  34         DISPATCH_STRUCT_HEADER(semaphore);
  35 #if USE_MACH_SEM
  36         semaphore_t dsema_port;
  37 #elif USE_POSIX_SEM
  38         sem_t dsema_sem;
  39 #elif USE_WIN32_SEM
  40         HANDLE dsema_handle;
  41 #else
  42 #error "No supported semaphore type"
  43 #endif
  44         long dsema_orig;
  45         long volatile dsema_value;
  46         union {
  47                 long volatile dsema_sent_ksignals;
  48                 long volatile dsema_group_waiters;
  49         };
  50         struct dispatch_continuation_s *volatile dsema_notify_head;
  51         struct dispatch_continuation_s *volatile dsema_notify_tail;
  52 };
  53
  54 DISPATCH_CLASS_DECL(group);
  55
  56 void _dispatch_semaphore_dispose(dispatch_object_t dou);
  57 size_t _dispatch_semaphore_debug(dispatch_object_t dou, char *buf,
  58                 size_t bufsiz);
  59
  60 typedef uintptr_t _dispatch_thread_semaphore_t;
  61
  62 _dispatch_thread_semaphore_t _dispatch_thread_semaphore_create(void);
  63 void _dispatch_thread_semaphore_dispose(_dispatch_thread_semaphore_t);
  64 void _dispatch_thread_semaphore_wait(_dispatch_thread_semaphore_t);
  65 void _dispatch_thread_semaphore_signal(_dispatch_thread_semaphore_t);
  66
  67 DISPATCH_ALWAYS_INLINE
  68 static inline _dispatch_thread_semaphore_t
  69 _dispatch_get_thread_semaphore(void)
  70 {
  71         _dispatch_thread_semaphore_t sema = (_dispatch_thread_semaphore_t)
  72                         _dispatch_thread_getspecific(dispatch_sema4_key);
  73         if (slowpath(!sema)) {
  74                 return _dispatch_thread_semaphore_create();
  75         }
  76         _dispatch_thread_setspecific(dispatch_sema4_key, NULL);
  77         return sema;
  78 }
  79
  80 DISPATCH_ALWAYS_INLINE
  81 static inline void
  82 _dispatch_put_thread_semaphore(_dispatch_thread_semaphore_t sema)
  83 {
  84         _dispatch_thread_semaphore_t old_sema = (_dispatch_thread_semaphore_t)
  85                         _dispatch_thread_getspecific(dispatch_sema4_key);
  86         _dispatch_thread_setspecific(dispatch_sema4_key, (void*)sema);
  87         if (slowpath(old_sema)) {
  88                 return _dispatch_thread_semaphore_dispose(old_sema);
  89         }
  90 }
  91
  92 #endif