andre@0: /* This Source Code Form is subject to the terms of the Mozilla Public
andre@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
andre@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
andre@0: /*
andre@0:  * pkix_pl_rwlock.c
andre@0:  *
andre@0:  * Read/Write Lock Functions
andre@0:  *
andre@0:  */
andre@0: 
andre@0: #include "pkix_pl_rwlock.h"
andre@0: 
andre@0: /* --Private-Functions-------------------------------------------- */
andre@0: 
andre@0: static PKIX_Error *
andre@0: pkix_pl_RWLock_Destroy(
andre@0:         PKIX_PL_Object *object,
andre@0:         void *plContext)
andre@0: {
andre@0:         PKIX_PL_RWLock* rwlock = NULL;
andre@0: 
andre@0:         PKIX_ENTER(RWLOCK, "pkix_pl_RWLock_Destroy");
andre@0:         PKIX_NULLCHECK_ONE(object);
andre@0: 
andre@0:         PKIX_CHECK(pkix_CheckType(object, PKIX_RWLOCK_TYPE, plContext),
andre@0:                     PKIX_OBJECTNOTRWLOCK);
andre@0: 
andre@0:         rwlock = (PKIX_PL_RWLock*) object;
andre@0: 
andre@0:         PKIX_RWLOCK_DEBUG("Calling PR_DestroyRWLock)\n");
andre@0:         PR_DestroyRWLock(rwlock->lock);
andre@0:         rwlock->lock = NULL;
andre@0: 
andre@0: cleanup:
andre@0: 
andre@0:         PKIX_RETURN(RWLOCK);
andre@0: }
andre@0: 
andre@0: /*
andre@0:  * FUNCTION: pkix_pl_RWLock_RegisterSelf
andre@0:  * DESCRIPTION:
andre@0:  *  Registers PKIX_RWLOCK_TYPE and its related functions with systemClasses[]
andre@0:  * THREAD SAFETY:
andre@0:  *  Not Thread Safe - for performance and complexity reasons
andre@0:  *
andre@0:  *  Since this function is only called by PKIX_PL_Initialize, which should
andre@0:  *  only be called once, it is acceptable that this function is not
andre@0:  *  thread-safe.
andre@0:  */
andre@0: PKIX_Error *
andre@0: pkix_pl_RWLock_RegisterSelf(
andre@0:         void *plContext)
andre@0: {
andre@0: 
andre@0:         extern pkix_ClassTable_Entry systemClasses[PKIX_NUMTYPES];
andre@0:         pkix_ClassTable_Entry entry;
andre@0: 
andre@0:         PKIX_ENTER(RWLOCK, "pkix_pl_RWLock_RegisterSelf");
andre@0: 
andre@0:         entry.description = "RWLock";
andre@0:         entry.objCounter = 0;
andre@0:         entry.typeObjectSize = sizeof(PKIX_PL_RWLock);
andre@0:         entry.destructor = pkix_pl_RWLock_Destroy;
andre@0:         entry.equalsFunction = NULL;
andre@0:         entry.hashcodeFunction = NULL;
andre@0:         entry.toStringFunction = NULL;
andre@0:         entry.comparator = NULL;
andre@0:         entry.duplicateFunction = NULL;
andre@0: 
andre@0:         systemClasses[PKIX_RWLOCK_TYPE] = entry;
andre@0: 
andre@0:         PKIX_RETURN(RWLOCK);
andre@0: }
andre@0: 
andre@0: /* --Public-Functions--------------------------------------------- */
andre@0: 
andre@0: PKIX_Error *
andre@0: PKIX_PL_RWLock_Create(
andre@0:         PKIX_PL_RWLock **pNewLock,
andre@0:         void *plContext)
andre@0: {
andre@0:         PKIX_PL_RWLock *rwLock = NULL;
andre@0: 
andre@0:         PKIX_ENTER(RWLOCK, "PKIX_PL_RWLock_Create");
andre@0:         PKIX_NULLCHECK_ONE(pNewLock);
andre@0: 
andre@0:         PKIX_CHECK(PKIX_PL_Object_Alloc
andre@0:                     (PKIX_RWLOCK_TYPE,
andre@0:                     sizeof (PKIX_PL_RWLock),
andre@0:                     (PKIX_PL_Object **)&rwLock,
andre@0:                     plContext),
andre@0:                     PKIX_ERRORALLOCATINGRWLOCK);
andre@0: 
andre@0:         PKIX_RWLOCK_DEBUG("\tCalling PR_NewRWLock)\n");
andre@0:         rwLock->lock = PR_NewRWLock(PR_RWLOCK_RANK_NONE, "PKIX RWLock");
andre@0: 
andre@0:         if (rwLock->lock == NULL) {
andre@0:                 PKIX_DECREF(rwLock);
andre@0:                 PKIX_ERROR(PKIX_OUTOFMEMORY);
andre@0:         }
andre@0: 
andre@0:         rwLock->readCount = 0;
andre@0:         rwLock->writeLocked = PKIX_FALSE;
andre@0: 
andre@0:         *pNewLock = rwLock;
andre@0: 
andre@0: cleanup:
andre@0: 
andre@0:         PKIX_RETURN(RWLOCK);
andre@0: }
andre@0: 
andre@0: PKIX_Error *
andre@0: PKIX_PL_AcquireReaderLock(
andre@0:         PKIX_PL_RWLock *lock,
andre@0:         void *plContext)
andre@0: {
andre@0:         PKIX_ENTER(RWLOCK, "PKIX_PL_AcquireReaderLock");
andre@0:         PKIX_NULLCHECK_ONE(lock);
andre@0: 
andre@0:         PKIX_RWLOCK_DEBUG("\tCalling PR_RWLock_Rlock)\n");
andre@0:         (void) PR_RWLock_Rlock(lock->lock);
andre@0: 
andre@0:         lock->readCount++;
andre@0: 
andre@0:         PKIX_RETURN(RWLOCK);
andre@0: }
andre@0: 
andre@0: PKIX_Error *
andre@0: PKIX_PL_ReleaseReaderLock(
andre@0:         PKIX_PL_RWLock *lock,
andre@0:         void *plContext)
andre@0: {
andre@0:         PKIX_ENTER(RWLOCK, "PKIX_PL_ReleaseReaderLock");
andre@0:         PKIX_NULLCHECK_ONE(lock);
andre@0: 
andre@0:         PKIX_RWLOCK_DEBUG("\tCalling PR_RWLock_Unlock)\n");
andre@0:         (void) PR_RWLock_Unlock(lock->lock);
andre@0: 
andre@0:         lock->readCount--;
andre@0: 
andre@0:         PKIX_RETURN(RWLOCK);
andre@0: }
andre@0: 
andre@0: PKIX_Error *
andre@0: PKIX_PL_IsReaderLockHeld(
andre@0:         PKIX_PL_RWLock *lock,
andre@0:         PKIX_Boolean *pIsHeld,
andre@0:         void *plContext)
andre@0: {
andre@0:         PKIX_ENTER(RWLOCK, "PKIX_PL_IsReaderLockHeld");
andre@0:         PKIX_NULLCHECK_TWO(lock, pIsHeld);
andre@0: 
andre@0:         *pIsHeld = (lock->readCount > 0)?PKIX_TRUE:PKIX_FALSE;
andre@0: 
andre@0:         PKIX_RETURN(RWLOCK);
andre@0: }
andre@0: 
andre@0: PKIX_Error *
andre@0: PKIX_PL_AcquireWriterLock(
andre@0:         PKIX_PL_RWLock *lock,
andre@0:         void *plContext)
andre@0: {
andre@0:         PKIX_ENTER(RWLOCK, "PKIX_PL_AcquireWriterLock");
andre@0:         PKIX_NULLCHECK_ONE(lock);
andre@0: 
andre@0:         PKIX_RWLOCK_DEBUG("\tCalling PR_RWLock_Wlock\n");
andre@0:         (void) PR_RWLock_Wlock(lock->lock);
andre@0: 
andre@0:         if (lock->readCount > 0) {
andre@0:                 PKIX_ERROR(PKIX_LOCKHASNONZEROREADCOUNT);
andre@0:         }
andre@0: 
andre@0:         /* We should never acquire a write lock if the lock is held */
andre@0:         lock->writeLocked = PKIX_TRUE;
andre@0: 
andre@0: cleanup:
andre@0: 
andre@0:         PKIX_RETURN(RWLOCK);
andre@0: }
andre@0: 
andre@0: PKIX_Error *
andre@0: PKIX_PL_ReleaseWriterLock(
andre@0:         PKIX_PL_RWLock *lock,
andre@0:         void *plContext)
andre@0: {
andre@0:         PKIX_ENTER(RWLOCK, "PKIX_PL_ReleaseWriterLock");
andre@0:         PKIX_NULLCHECK_ONE(lock);
andre@0: 
andre@0:         if (lock->readCount > 0) {
andre@0:                 PKIX_ERROR(PKIX_LOCKHASNONZEROREADCOUNT);
andre@0:         }
andre@0: 
andre@0:         PKIX_RWLOCK_DEBUG("\tCalling PR_RWLock_Unlock)\n");
andre@0:         (void) PR_RWLock_Unlock(lock->lock);
andre@0: 
andre@0:         /* XXX Need to think about thread safety here */
andre@0:         /* There should be a single lock holder  */
andre@0:         lock->writeLocked = PKIX_FALSE;
andre@0: 
andre@0: cleanup:
andre@0: 
andre@0:         PKIX_RETURN(RWLOCK);
andre@0: }
andre@0: 
andre@0: PKIX_Error *
andre@0: PKIX_PL_IsWriterLockHeld(
andre@0:         PKIX_PL_RWLock *lock,
andre@0:         PKIX_Boolean *pIsHeld,
andre@0:         void *plContext)
andre@0: {
andre@0:         PKIX_ENTER(RWLOCK, "PKIX_PL_IsWriterLockHeld");
andre@0:         PKIX_NULLCHECK_TWO(lock, pIsHeld);
andre@0: 
andre@0:         *pIsHeld = lock->writeLocked;
andre@0: 
andre@0:         PKIX_RETURN(RWLOCK);
andre@0: }