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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-21 11:44:51 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-21 11:44:51 +0000 |
commit | 9e3c08db40b8916968b9f30096c7be3f00ce9647 (patch) | |
tree | a68f146d7fa01f0134297619fbe7e33db084e0aa /nsprpub/pr/src/threads/prsem.c | |
parent | Initial commit. (diff) | |
download | thunderbird-9e3c08db40b8916968b9f30096c7be3f00ce9647.tar.xz thunderbird-9e3c08db40b8916968b9f30096c7be3f00ce9647.zip |
Adding upstream version 1:115.7.0.upstream/1%115.7.0upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'nsprpub/pr/src/threads/prsem.c')
-rw-r--r-- | nsprpub/pr/src/threads/prsem.c | 141 |
1 files changed, 141 insertions, 0 deletions
diff --git a/nsprpub/pr/src/threads/prsem.c b/nsprpub/pr/src/threads/prsem.c new file mode 100644 index 0000000000..120075b0cb --- /dev/null +++ b/nsprpub/pr/src/threads/prsem.c @@ -0,0 +1,141 @@ +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* 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 "primpl.h" +#include "obsolete/prsem.h" + +/************************************************************************/ + +/* +** Create a new semaphore. +*/ +PR_IMPLEMENT(PRSemaphore*) PR_NewSem(PRUintn value) +{ + PRSemaphore *sem; + PRCondVar *cvar; + PRLock *lock; + + sem = PR_NEWZAP(PRSemaphore); + if (sem) { +#ifdef HAVE_CVAR_BUILT_ON_SEM + _PR_MD_NEW_SEM(&sem->md, value); +#else + lock = PR_NewLock(); + if (!lock) { + PR_DELETE(sem); + return NULL; + } + + cvar = PR_NewCondVar(lock); + if (!cvar) { + PR_DestroyLock(lock); + PR_DELETE(sem); + return NULL; + } + sem->cvar = cvar; + sem->count = value; +#endif + } + return sem; +} + +/* +** Destroy a semaphore. There must be no thread waiting on the semaphore. +** The caller is responsible for guaranteeing that the semaphore is +** no longer in use. +*/ +PR_IMPLEMENT(void) PR_DestroySem(PRSemaphore *sem) +{ +#ifdef HAVE_CVAR_BUILT_ON_SEM + _PR_MD_DESTROY_SEM(&sem->md); +#else + PR_ASSERT(sem->waiters == 0); + + PR_DestroyLock(sem->cvar->lock); + PR_DestroyCondVar(sem->cvar); +#endif + 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) +{ + PRStatus status = PR_SUCCESS; + +#ifdef HAVE_CVAR_BUILT_ON_SEM + return _PR_MD_WAIT_SEM(&sem->md); +#else + PR_Lock(sem->cvar->lock); + while (sem->count == 0) { + sem->waiters++; + status = PR_WaitCondVar(sem->cvar, PR_INTERVAL_NO_TIMEOUT); + sem->waiters--; + if (status != PR_SUCCESS) { + break; + } + } + if (status == PR_SUCCESS) { + sem->count--; + } + PR_Unlock(sem->cvar->lock); +#endif + + return (status); +} + +/* +** 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) +{ +#ifdef HAVE_CVAR_BUILT_ON_SEM + _PR_MD_POST_SEM(&sem->md); +#else + PR_Lock(sem->cvar->lock); + if (sem->waiters) { + PR_NotifyCondVar(sem->cvar); + } + sem->count++; + PR_Unlock(sem->cvar->lock); +#endif +} + +#if DEBUG +/* +** Returns the value of the semaphore referenced by sem without affecting +** the state of the semaphore. The value represents the semaphore vaule +** at the time of the call, but may not be the actual value when the +** caller inspects it. (FOR DEBUGGING ONLY) +*/ +PR_IMPLEMENT(PRUintn) PR_GetValueSem(PRSemaphore *sem) +{ + PRUintn rv; + +#ifdef HAVE_CVAR_BUILT_ON_SEM + rv = _PR_MD_GET_VALUE_SEM(&sem->md); +#else + PR_Lock(sem->cvar->lock); + rv = sem->count; + PR_Unlock(sem->cvar->lock); +#endif + + return rv; +} +#endif |