LockDis.c revision b4ee4795 
1
2/*
3
4Copyright 1993, 1998  The Open Group
5
6Permission to use, copy, modify, distribute, and sell this software and its
7documentation for any purpose is hereby granted without fee, provided that
8the above copyright notice appear in all copies and that both that
9copyright notice and this permission notice appear in supporting
10documentation.
11
12The above copyright notice and this permission notice shall be included in
13all copies or substantial portions of the Software.
14
15THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
18OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
19AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
20CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
21
22Except as contained in this notice, the name of The Open Group shall not be
23used in advertising or otherwise to promote the sale, use or other dealings
24in this Software without prior written authorization from The Open Group.
25
26*/
27
28/*
29 * Author: Stephen Gildea, MIT X Consortium
30 *
31 * XLockDis.c - multi-thread application-level locking routines
32 */
33
34#ifdef HAVE_CONFIG_H
35#include <config.h>
36#endif
37#include "Xlibint.h"
38#ifdef XTHREADS
39#include "locking.h"
40#endif
41
42void
43XLockDisplay(
44    register Display* dpy)
45{
46#ifdef XTHREADS
47    LockDisplay(dpy);
48    if (dpy->lock)
49	(*dpy->lock->user_lock_display)(dpy);
50    /*
51     * We want the threads in the reply queue to all get out before
52     * XLockDisplay returns, in case they have any side effects the
53     * caller of XLockDisplay was trying to protect against.
54     * XLockDisplay puts itself at the head of the event waiters queue
55     * to wait for all the replies to come in.
56     */
57    if (dpy->lock && dpy->lock->reply_awaiters) {
58	struct _XCVList *cvl;
59
60	cvl = (*dpy->lock->create_cvl)(dpy);
61
62	/* stuff ourselves on the head of the queue */
63	cvl->next = dpy->lock->event_awaiters;
64	dpy->lock->event_awaiters = cvl;
65
66	while (dpy->lock->reply_awaiters)
67	    ConditionWait(dpy, cvl->cv);
68	UnlockNextEventReader(dpy); /* pass the signal on */
69    }
70    UnlockDisplay(dpy);
71#endif
72}
73
74void
75XUnlockDisplay(
76    register Display* dpy)
77{
78#ifdef XTHREADS
79    LockDisplay(dpy);
80    if (dpy->lock)
81	(*dpy->lock->user_unlock_display)(dpy);
82    UnlockDisplay(dpy);
83#endif
84}
85