/* $Xorg: ChkIfEv.c,v 1.4 2001/02/09 02:03:31 xorgcvs Exp $ */ /* Copyright 1985, 1987, 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. */ /* $XFree86$ */ #define NEED_EVENTS #ifdef HAVE_CONFIG_H #include <config.h> #endif #include "Xlibint.h" /* * Check existing events in queue to find if any match. If so, return. * If not, flush buffer and see if any more events are readable. If one * matches, return. If all else fails, tell the user no events found. */ Bool XCheckIfEvent (dpy, event, predicate, arg) register Display *dpy; Bool (*predicate)( Display* /* display */, XEvent* /* event */, char* /* arg */ ); /* function to call */ register XEvent *event; /* XEvent to be filled in. */ char *arg; { register _XQEvent *prev, *qelt; unsigned long qe_serial = 0; int n; /* time through count */ LockDisplay(dpy); prev = NULL; for (n = 3; --n >= 0;) { 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; _XDeq(dpy, prev, qelt); UnlockDisplay(dpy); return True; } } if (prev) qe_serial = prev->qserial_num; switch (n) { case 2: _XEventsQueued(dpy, QueuedAfterReading); break; case 1: _XFlush(dpy); break; } if (prev && prev->qserial_num != qe_serial) /* another thread has snatched this event */ prev = NULL; } UnlockDisplay(dpy); return False; } #ifdef NX_TRANS_SOCKET /* * This is just like XCheckIfEvent() but doesn't * flush the output buffer if it can't read new * events. */ Bool XCheckIfEventNoFlush (dpy, event, predicate, arg) register Display *dpy; Bool (*predicate)( Display* /* display */, XEvent* /* event */, char* /* arg */ ); /* function to call */ register XEvent *event; /* XEvent to be filled in. */ char *arg; { register _XQEvent *prev, *qelt; unsigned long qe_serial = 0; int n; /* time through count */ LockDisplay(dpy); prev = NULL; for (n = 2; --n >= 0;) { 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; _XDeq(dpy, prev, qelt); UnlockDisplay(dpy); return True; } } if (prev) qe_serial = prev->qserial_num; switch (n) { case 1: _XEventsQueued(dpy, QueuedAfterReading); break; } if (prev && prev->qserial_num != qe_serial) /* another thread has snatched this event */ prev = NULL; } UnlockDisplay(dpy); return False; } #endif