1 files changed, 76 insertions, 0 deletions
diff --git a/libX11/src/PeekIfEv.c b/libX11/src/PeekIfEv.c
new file mode 100644
index 000000000..1d5b1ab9c
--- /dev/null
+++ b/libX11/src/PeekIfEv.c
@@ -0,0 +1,76 @@
+/* $Xorg: PeekIfEv.c,v 1.4 2001/02/09 02:03:35 xorgcvs Exp $ */
+/*
+
+Copyright 1986, 1998  The Open Group
+
+Permission to use, copy, modify, distribute, and sell this software and its
+documentation for any purpose is hereby granted without fee, provided that
+the above copyright notice appear in all copies and that both that
+copyright notice and this permission notice appear in supporting
+documentation.
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+Except as contained in this notice, the name of The Open Group shall not be
+used in advertising or otherwise to promote the sale, use or other dealings
+in this Software without prior written authorization from The Open Group.
+
+*/
+/* $XFree86: xc/lib/X11/PeekIfEv.c,v 1.4 2001/12/14 19:54:03 dawes Exp $ */
+
+#define NEED_EVENTS
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+#include "Xlibint.h"
+
+/*
+ * return the next event in the queue that satisfies the predicate.
+ * BUT do not remove it from the queue.
+ * If none found, flush, and then wait until one satisfies the predicate.
+ */
+
+int
+XPeekIfEvent (
+	register Display *dpy,
+	register XEvent *event,
+	Bool (*predicate)(
+			  Display*			/* display */,
+			  XEvent*			/* event */,
+			  char*				/* arg */
+			  ),
+	char *arg)
+{
+	register _XQEvent *prev, *qelt;
+	unsigned long qe_serial = 0;
+
+	LockDisplay(dpy);
+	prev = NULL;
+	while (1) {
+	    for (qelt = prev ? prev->next : dpy->head;
+		 qelt;
+		 prev = qelt, qelt = qelt->next) {
+		if(qelt->qserial_num > qe_serial
+		   && (*predicate)(dpy, &qelt->event, arg)) {
+		    *event = qelt->event;
+		    UnlockDisplay(dpy);
+		    return 0;
+		}
+	    }
+	    if (prev)
+		qe_serial = prev->qserial_num;
+	    _XReadEvents(dpy);
+	    if (prev && prev->qserial_num != qe_serial)
+		/* another thread has snatched this event */
+		prev = NULL;
+	}
+}
+