Subversion Repositories or1k

/*

 * 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 1.1.1.1 2002-01-16 10:26:01 markom Exp $

 */

#include "tkInt.h"

#include "tkPort.h"

#include "tkUnixInt.h"

extern int tclFocusDebug;

/*

 *----------------------------------------------------------------------

 *

 * 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;

}