headers/private/libroot/libroot_lock.h

   1 /*
   2  * Copyright 2002-2008, Axel Dörfler, axeld@pinc-software.de.
   3  * Distributed under the terms of the MIT License.
   4  *
   5  * Copyright 2001-2002, Travis Geiselbrecht. All rights reserved.
   6  * Distributed under the terms of the NewOS License.
   7  */
   8 #ifndef _LIBROOT_LOCK_H
   9 #define _LIBROOT_LOCK_H
  10
  11 #include <OS.h>
  12
  13
  14 // TODO: Copied from the kernel private lock.h/lock.c. We should somehow make
  15 // that code reusable.
  16
  17
  18 namespace BPrivate {
  19
  20
  21 typedef struct benaphore {
  22         sem_id  sem;
  23         int32   count;
  24 } benaphore;
  25
  26
  27 static inline status_t
  28 benaphore_init(benaphore *ben, const char *name)
  29 {
  30         if (ben == NULL || name == NULL)
  31                 return B_BAD_VALUE;
  32
  33         ben->count = 1;
  34         ben->sem = create_sem(0, name);
  35         if (ben->sem >= B_OK)
  36                 return B_OK;
  37
  38         return ben->sem;
  39 }
  40
  41
  42 static inline status_t
  43 benaphore_lock_etc(benaphore *ben, uint32 flags, bigtime_t timeout)
  44 {
  45 // TODO: This function really shouldn't be used, since timeouts screw the
  46 // benaphore behavior.
  47         if (atomic_add(&ben->count, -1) <= 0)
  48                 return acquire_sem_etc(ben->sem, 1, flags, timeout);
  49
  50         return B_OK;
  51 }
  52
  53
  54 static inline status_t
  55 benaphore_lock(benaphore *ben)
  56 {
  57         if (atomic_add(&ben->count, -1) <= 0) {
  58                 status_t error;
  59                 do {
  60                         error = acquire_sem(ben->sem);
  61                 } while (error == B_INTERRUPTED);
  62
  63                 return error;
  64         }
  65
  66         return B_OK;
  67 }
  68
  69
  70 static inline status_t
  71 benaphore_unlock(benaphore *ben)
  72 {
  73         if (atomic_add(&ben->count, 1) < 0)
  74                 return release_sem(ben->sem);
  75
  76         return B_OK;
  77 }
  78
  79
  80 }       // namespace BPrivate
  81
  82
  83 using BPrivate::benaphore;
  84 using BPrivate::benaphore_init;
  85 using BPrivate::benaphore_lock_etc;
  86 using BPrivate::benaphore_lock;
  87 using BPrivate::benaphore_unlock;
  88
  89
  90 #endif  // _LIBROOT_LOCK_H