michael@0: /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: /*
michael@0: ** File:		prrwlock.h
michael@0: ** Description:	API to basic reader-writer lock functions of NSPR.
michael@0: **
michael@0: **/
michael@0: 
michael@0: #ifndef prrwlock_h___
michael@0: #define prrwlock_h___
michael@0: 
michael@0: #include "prtypes.h"
michael@0: 
michael@0: PR_BEGIN_EXTERN_C
michael@0: 
michael@0: /*
michael@0:  * PRRWLock --
michael@0:  *
michael@0:  *	The reader writer lock, PRRWLock, is an opaque object to the clients
michael@0:  *	of NSPR.  All routines operate on a pointer to this opaque entity.
michael@0:  */
michael@0: 
michael@0: 
michael@0: typedef struct PRRWLock PRRWLock;
michael@0: 
michael@0: #define	PR_RWLOCK_RANK_NONE	0
michael@0: 
michael@0: 
michael@0: /***********************************************************************
michael@0: ** FUNCTION:    PR_NewRWLock
michael@0: ** DESCRIPTION:
michael@0: **  Returns a pointer to a newly created reader-writer lock object.
michael@0: ** INPUTS:      Lock rank
michael@0: **				Lock name
michael@0: ** OUTPUTS:     void
michael@0: ** RETURN:      PRRWLock*
michael@0: **   If the lock cannot be created because of resource constraints, NULL
michael@0: **   is returned.
michael@0: **  
michael@0: ***********************************************************************/
michael@0: NSPR_API(PRRWLock*) PR_NewRWLock(PRUint32 lock_rank, const char *lock_name);
michael@0: 
michael@0: /***********************************************************************
michael@0: ** FUNCTION:    PR_DestroyRWLock
michael@0: ** DESCRIPTION:
michael@0: **  Destroys a given RW lock object.
michael@0: ** INPUTS:      PRRWLock *lock - Lock to be freed.
michael@0: ** OUTPUTS:     void
michael@0: ** RETURN:      None
michael@0: ***********************************************************************/
michael@0: NSPR_API(void) PR_DestroyRWLock(PRRWLock *lock);
michael@0: 
michael@0: /***********************************************************************
michael@0: ** FUNCTION:    PR_RWLock_Rlock
michael@0: ** DESCRIPTION:
michael@0: **  Apply a read lock (non-exclusive) on a RWLock
michael@0: ** INPUTS:      PRRWLock *lock - Lock to be read-locked.
michael@0: ** OUTPUTS:     void
michael@0: ** RETURN:      None
michael@0: ***********************************************************************/
michael@0: NSPR_API(void) PR_RWLock_Rlock(PRRWLock *lock);
michael@0: 
michael@0: /***********************************************************************
michael@0: ** FUNCTION:    PR_RWLock_Wlock
michael@0: ** DESCRIPTION:
michael@0: **  Apply a write lock (exclusive) on a RWLock
michael@0: ** INPUTS:      PRRWLock *lock - Lock to write-locked.
michael@0: ** OUTPUTS:     void
michael@0: ** RETURN:      None
michael@0: ***********************************************************************/
michael@0: NSPR_API(void) PR_RWLock_Wlock(PRRWLock *lock);
michael@0: 
michael@0: /***********************************************************************
michael@0: ** FUNCTION:    PR_RWLock_Unlock
michael@0: ** DESCRIPTION:
michael@0: **  Release a RW lock. Unlocking an unlocked lock has undefined results.
michael@0: ** INPUTS:      PRRWLock *lock - Lock to unlocked.
michael@0: ** OUTPUTS:     void
michael@0: ** RETURN:      void
michael@0: ***********************************************************************/
michael@0: NSPR_API(void) PR_RWLock_Unlock(PRRWLock *lock);
michael@0: 
michael@0: PR_END_EXTERN_C
michael@0: 
michael@0: #endif /* prrwlock_h___ */