/*
 * The contents of this file are subject to the Mozilla Public
 * License Version 1.1 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy of
 * the License at http://www.mozilla.org/MPL/
 * 
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 * 
 * The Original Code is the Netscape security libraries.
 * 
 * The Initial Developer of the Original Code is Netscape
 * Communications Corporation.  Portions created by Netscape are 
 * Copyright (C) 1994-2000 Netscape Communications Corporation.  All
 * Rights Reserved.
 * 
 * Contributor(s):
 * 
 * Alternatively, the contents of this file may be used under the
 * terms of the GNU General Public License Version 2 or later (the
 * "GPL"), in which case the provisions of the GPL are applicable 
 * instead of those above.  If you wish to allow use of your 
 * version of this file only under the terms of the GPL and not to
 * allow others to use your version of this file under the MPL,
 * indicate your decision by deleting the provisions above and
 * replace them with the notice and other provisions required by
 * the GPL.  If you do not delete the provisions above, a recipient
 * may use your version of this file under either the MPL or the
 * GPL.
 */
/*
 * Locking and queue management primatives
 *
 */

#include "seccomon.h"
#include "nssilock.h"
#include "prmon.h"
#include "secmod.h"
#include "secmodi.h"
#include "prlong.h"
#include "nssrwlk.h"

/*
 * create a new lock for a Module List
 */
SECMODListLock *SECMOD_NewListLock() 
{
#ifdef PKCS11_USE_THREADS
    return (SECMODListLock *)NSSRWLock_New( 10, "moduleListLock");
#else
    return (SECMODListLock *)1;
#endif
}

/*
 * destroy the lock
 */
void SECMOD_DestroyListLock(SECMODListLock *lock) 
{
    PK11_USE_THREADS(NSSRWLock_Destroy((NSSRWLock *)lock);)
}


/*
 * Lock the List for Read: NOTE: this assumes the reading isn't so common
 * the writing will be starved.
 */
void SECMOD_GetReadLock(SECMODListLock *modLock) 
{
    PK11_USE_THREADS(NSSRWLock_LockRead((NSSRWLock *)modLock);)
}

/*
 * Release the Read lock
 */
void SECMOD_ReleaseReadLock(SECMODListLock *modLock) 
{
    PK11_USE_THREADS(NSSRWLock_UnlockRead((NSSRWLock *)modLock);)
}


/*
 * lock the list for Write
 */
void SECMOD_GetWriteLock(SECMODListLock *modLock) 
{
    PK11_USE_THREADS(NSSRWLock_LockWrite((NSSRWLock *)modLock);)
}


/*
 * Release the Write Lock: NOTE, this code is pretty inefficient if you have
 * lots of write collisions.
 */
void SECMOD_ReleaseWriteLock(SECMODListLock *modLock) 
{
    PK11_USE_THREADS(NSSRWLock_UnlockWrite((NSSRWLock *)modLock);)
}


/*
 * must Hold the Write lock
 */
void
SECMOD_RemoveList(SECMODModuleList **parent, SECMODModuleList *child) 
{
    *parent = child->next;
    child->next = NULL;
}

/*
 * if lock is not specified, it must already be held
 */
void
SECMOD_AddList(SECMODModuleList *parent, SECMODModuleList *child, 
							SECMODListLock *lock) 
{
    if (lock) { SECMOD_GetWriteLock(lock); }

    child->next = parent->next;
    parent->next = child;

   if (lock) { SECMOD_ReleaseWriteLock(lock); }
}