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Diffstat (limited to 'nsprpub/pr/src/bthreads/btsem.c')
-rw-r--r-- | nsprpub/pr/src/bthreads/btsem.c | 98 |
1 files changed, 98 insertions, 0 deletions
diff --git a/nsprpub/pr/src/bthreads/btsem.c b/nsprpub/pr/src/bthreads/btsem.c new file mode 100644 index 000000000..011ee6bd3 --- /dev/null +++ b/nsprpub/pr/src/bthreads/btsem.c @@ -0,0 +1,98 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +#include <kernel/OS.h> + +#include "primpl.h" + +/* +** Create a new semaphore object. +*/ +PR_IMPLEMENT(PRSemaphore*) + PR_NewSem (PRUintn value) +{ + PRSemaphore *semaphore; + + if (!_pr_initialized) _PR_ImplicitInitialization(); + + semaphore = PR_NEWZAP(PRSemaphore); + if (NULL != semaphore) { + if ((semaphore->sem = create_sem(value, "nspr_sem")) < B_NO_ERROR) + return NULL; + else + return semaphore; + } + return NULL; +} + +/* +** Destroy the given semaphore object. +** +*/ +PR_IMPLEMENT(void) + PR_DestroySem (PRSemaphore *sem) +{ + status_t result; + + PR_ASSERT(sem != NULL); + result = delete_sem(sem->sem); + PR_ASSERT(result == B_NO_ERROR); + PR_DELETE(sem); +} + +/* +** Wait on a Semaphore. +** +** This routine allows a calling thread to wait or proceed depending upon +** the state of the semahore sem. The thread can proceed only if the +** counter value of the semaphore sem is currently greater than 0. If the +** value of semaphore sem is positive, it is decremented by one and the +** routine returns immediately allowing the calling thread to continue. If +** the value of semaphore sem is 0, the calling thread blocks awaiting the +** semaphore to be released by another thread. +** +** This routine can return PR_PENDING_INTERRUPT if the waiting thread +** has been interrupted. +*/ +PR_IMPLEMENT(PRStatus) + PR_WaitSem (PRSemaphore *sem) +{ + PR_ASSERT(sem != NULL); + if (acquire_sem(sem->sem) == B_NO_ERROR) + return PR_SUCCESS; + else + return PR_FAILURE; +} + +/* +** This routine increments the counter value of the semaphore. If other +** threads are blocked for the semaphore, then the scheduler will +** determine which ONE thread will be unblocked. +*/ +PR_IMPLEMENT(void) + PR_PostSem (PRSemaphore *sem) +{ + status_t result; + + PR_ASSERT(sem != NULL); + result = release_sem_etc(sem->sem, 1, B_DO_NOT_RESCHEDULE); + PR_ASSERT(result == B_NO_ERROR); +} + +/* +** Returns the value of the semaphore referenced by sem without affecting +** the state of the semaphore. The value represents the semaphore value +** at the time of the call, but may not be the actual value when the +** caller inspects it. +*/ +PR_IMPLEMENT(PRUintn) + PR_GetValueSem (PRSemaphore *sem) +{ + sem_info info; + + PR_ASSERT(sem != NULL); + get_sem_info(sem->sem, &info); + return info.count; +} |