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|
/*----------------------------------------------------------------------------
| Copyright (C) 1999 Jochen C. Loewer (loewerj@hotmail.com)
+-----------------------------------------------------------------------------
|
| The contents of this file are subject to the Mozilla Public License
| Version 2.0 (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 tDOM.
|
| The Initial Developer of the Original Code is Jochen Loewer
| Portions created by Jochen Loewer are Copyright (C) 1998, 1999
| Jochen Loewer. All Rights Reserved.
|
| This implements many-readers/single-writer locking of DOM documents.
|
| Contributor(s):
| May02 Zoran Vasiljevic Added this file.
|
\---------------------------------------------------------------------------*/
#ifdef TCL_THREADS
#include <dom.h>
/*----------------------------------------------------------------------------
| Global list of document lock structures. These should be finalized
| only on application exit.
|
\---------------------------------------------------------------------------*/
static Tcl_Mutex lockMutex = 0;
static domlock *domLocks = NULL;
/*----------------------------------------------------------------------------
| Lock the document according to passed flag
|
\---------------------------------------------------------------------------*/
void
domLocksLock(domlock *dl, int how)
{
Tcl_MutexLock(&dl->mutex);
switch (how) {
case LOCK_READ:
while (dl->lrcnt < 0 || dl->numwr > 0) {
dl->numrd++;
Tcl_ConditionWait(&dl->rcond, &dl->mutex, NULL);
dl->numrd--;
}
dl->lrcnt++;
break;
case LOCK_WRITE:
while (dl->lrcnt != 0) {
dl->numwr++;
Tcl_ConditionWait(&dl->wcond, &dl->mutex, NULL);
dl->numwr--;
}
dl->lrcnt = -1; /* This designates the sole writer */
break;
}
Tcl_MutexUnlock(&dl->mutex);
}
/*----------------------------------------------------------------------------
| Unlock the previously locked document.
|
\---------------------------------------------------------------------------*/
void
domLocksUnlock(domlock *dl)
{
Tcl_MutexLock(&dl->mutex);
if (--dl->lrcnt < 0) {
dl->lrcnt = 0;
}
if (dl->numwr) {
Tcl_ConditionNotify(&dl->wcond);
} else if (dl->numrd) {
Tcl_ConditionNotify(&dl->rcond);
}
Tcl_MutexUnlock (&dl->mutex);
}
/*----------------------------------------------------------------------------
| Associate a lock with the document..
|
\---------------------------------------------------------------------------*/
void
domLocksAttach(domDocument *doc)
{
domlock *dl;
Tcl_MutexLock(&lockMutex);
dl = domLocks;
if (dl == NULL) {
dl = (domlock*)MALLOC(sizeof(domlock));
memset(dl, 0, sizeof(domlock));
} else {
domLocks = dl->next;
}
dl->doc = doc;
doc->lock = dl;
Tcl_MutexUnlock(&lockMutex);
}
/*----------------------------------------------------------------------------
| Divorce DOM document from its lock. The lock structure is not
| disposed and may be used for locking other documents.
|
\---------------------------------------------------------------------------*/
void
domLocksDetach(domDocument *doc)
{
domlock *dl = doc->lock;
Tcl_MutexLock(&lockMutex);
if (dl->doc != doc) {
domPanic("document lock mismatch");
}
dl->next = domLocks;
domLocks = dl;
dl->doc = NULL;
doc->lock = NULL;
Tcl_MutexUnlock(&lockMutex);
}
/*----------------------------------------------------------------------------
| Reclaim storage used for lock structures. This should be done only
| on application exit.
|
\---------------------------------------------------------------------------*/
void
domLocksFinalize(ClientData UNUSED(dummy))
{
domlock *tmp, *dl;
Tcl_MutexLock(&lockMutex);
dl = domLocks;
while (dl != NULL) {
Tcl_MutexFinalize(&dl->mutex);
Tcl_ConditionFinalize(&dl->rcond);
Tcl_ConditionFinalize(&dl->wcond);
tmp = dl;
dl = dl->next;
FREE((char*)tmp);
}
domLocks = NULL;
Tcl_MutexUnlock(&lockMutex);
}
#endif /* TCL_THREADS */
|
