src/system/libroot/os/locks/recursive_lock.cpp

   1 /*
   2  * Copyright 2009, Michael Lotz, mmlr@mlotz.ch.
   3  * Copyright 2008-2010, Ingo Weinhold, ingo_weinhold@gmx.de.
   4  * Copyright 2002-2009, Axel Dörfler, axeld@pinc-software.de. All rights reserved.
   5  * Distributed under the terms of the MIT License.
   6  *
   7  * Copyright 2001-2002, Travis Geiselbrecht. All rights reserved.
   8  * Distributed under the terms of the NewOS License.
   9  */
  10
  11
  12 #include <locks.h>
  13
  14 #include <OS.h>
  15
  16
  17 // #pragma mark - recursive lock
  18
  19
  20 int32
  21 __recursive_lock_get_recursion(recursive_lock *lock)
  22 {
  23         if (lock->holder == find_thread(NULL))
  24                 return lock->recursion;
  25
  26         return -1;
  27 }
  28
  29
  30 void
  31 __recursive_lock_init(recursive_lock *lock, const char *name)
  32 {
  33         recursive_lock_init_etc(lock, name, 0);
  34 }
  35
  36
  37 void
  38 __recursive_lock_init_etc(recursive_lock *lock, const char *name, uint32 flags)
  39 {
  40         lock->holder = -1;
  41         lock->recursion = 0;
  42         mutex_init_etc(&lock->lock, name, flags);
  43 }
  44
  45
  46 void
  47 __recursive_lock_destroy(recursive_lock *lock)
  48 {
  49         if (lock == NULL)
  50                 return;
  51
  52         mutex_destroy(&lock->lock);
  53 }
  54
  55
  56 status_t
  57 __recursive_lock_lock(recursive_lock *lock)
  58 {
  59         thread_id thread = find_thread(NULL);
  60
  61         if (thread != lock->holder) {
  62                 mutex_lock(&lock->lock);
  63                 lock->holder = thread;
  64         }
  65
  66         lock->recursion++;
  67         return B_OK;
  68 }
  69
  70
  71 void
  72 __recursive_lock_unlock(recursive_lock *lock)
  73 {
  74         if (find_thread(NULL) != lock->holder) {
  75                 debugger("recursive_lock unlocked by non-holder thread!\n");
  76                 return;
  77         }
  78
  79         if (--lock->recursion == 0) {
  80                 lock->holder = -1;
  81                 mutex_unlock(&lock->lock);
  82         }
  83 }