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/*
* tkUnixFocus.c --
*
* This file contains platform specific procedures that manage
* focus for Tk.
*
* Copyright (c) 1997 Sun Microsystems, Inc.
*
* See the file "license.terms" for information on usage and redistribution
* of this file, and for a DISCLAIMER OF ALL WARRANTIES.
*
* RCS: @(#) $Id: tkUnixFocus.c,v 1.3 1999/04/16 01:51:46 stanton Exp $
*/
#include "tkInt.h"
#include "tkPort.h"
#include "tkUnixInt.h"
/*
*----------------------------------------------------------------------
*
* TkpChangeFocus --
*
* This procedure is invoked to move the official X focus from
* one window to another.
*
* Results:
* The return value is the serial number of the command that
* changed the focus. It may be needed by the caller to filter
* out focus change events that were queued before the command.
* If the procedure doesn't actually change the focus then
* it returns 0.
*
* Side effects:
* The official X focus window changes; the application's focus
* window isn't changed by this procedure.
*
*----------------------------------------------------------------------
*/
int
TkpChangeFocus(winPtr, force)
TkWindow *winPtr; /* Window that is to receive the X focus. */
int force; /* Non-zero means claim the focus even
* if it didn't originally belong to
* topLevelPtr's application. */
{
TkDisplay *dispPtr = winPtr->dispPtr;
Tk_ErrorHandler errHandler;
Window window, root, parent, *children;
unsigned int numChildren, serial;
TkWindow *winPtr2;
int dummy;
/*
* Don't set the X focus to a window that's marked
* override-redirect. This is a hack to avoid problems with menus
* under olvwm: if we move the focus then the focus can get lost
* during keyboard traversal. Fortunately, we don't really need to
* move the focus for menus: events will still find their way to the
* focus window, and menus aren't decorated anyway so the window
* manager doesn't need to hear about the focus change in order to
* redecorate the menu.
*/
serial = 0;
if (winPtr->atts.override_redirect) {
return serial;
}
/*
* Check to make sure that the focus is still in one of the windows
* of this application or one of their descendants. Furthermore,
* grab the server to make sure that the focus doesn't change in the
* middle of this operation.
*/
XGrabServer(dispPtr->display);
if (!force) {
/*
* Find the focus window, then see if it or one of its ancestors
* is a window in our application (it's possible that the focus
* window is in an embedded application, which may or may not be
* in the same process.
*/
XGetInputFocus(dispPtr->display, &window, &dummy);
while (1) {
winPtr2 = (TkWindow *) Tk_IdToWindow(dispPtr->display, window);
if ((winPtr2 != NULL) && (winPtr2->mainPtr == winPtr->mainPtr)) {
break;
}
if ((window == PointerRoot) || (window == None)) {
goto done;
}
XQueryTree(dispPtr->display, window, &root, &parent, &children,
&numChildren);
if (children != NULL) {
XFree((void *) children);
}
if (parent == root) {
goto done;
}
window = parent;
}
}
/*
* Tell X to change the focus. Ignore errors that occur when changing
* the focus: it is still possible that the window we're focussing
* to could have gotten unmapped, which will generate an error.
*/
errHandler = Tk_CreateErrorHandler(dispPtr->display, -1, -1, -1,
(Tk_ErrorProc *) NULL, (ClientData) NULL);
if (winPtr->window == None) {
panic("ChangeXFocus got null X window");
}
XSetInputFocus(dispPtr->display, winPtr->window, RevertToParent,
CurrentTime);
Tk_DeleteErrorHandler(errHandler);
/*
* Remember the current serial number for the X server and issue
* a dummy server request. This marks the position at which we
* changed the focus, so we can distinguish FocusIn and FocusOut
* events on either side of the mark.
*/
serial = NextRequest(winPtr->display);
XNoOp(winPtr->display);
done:
XUngrabServer(dispPtr->display);
/*
* After ungrabbing the server, it's important to flush the output
* immediately so that the server sees the ungrab command. Otherwise
* we might do something else that needs to communicate with the
* server (such as invoking a subprocess that needs to do I/O to
* the screen); if the ungrab command is still sitting in our
* output buffer, we could deadlock.
*/
XFlush(dispPtr->display);
return serial;
}
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