Initial revision

1 files changed, 998 insertions, 0 deletions

diff --git a/generic/tkFocus.c b/generic/tkFocus.c
new file mode 100644
index 0000000..fe8f2c5
--- /dev/null
+++ b/generic/tkFocus.c
@@ -0,0 +1,998 @@
+/* 
+ * tkFocus.c --
+ *
+ *	This file contains procedures that manage the input
+ *	focus for Tk.
+ *
+ * Copyright (c) 1990-1994 The Regents of the University of California.
+ * Copyright (c) 1994-1997 Sun Microsystems, Inc.
+ *
+ * See the file "license.terms" for information on usage and redistribution
+ * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
+ *
+ * SCCS: @(#) tkFocus.c 1.48 97/10/31 09:55:22
+ */
+
+#include "tkInt.h"
+#include "tkPort.h"
+
+
+/*
+ * For each top-level window that has ever received the focus, there
+ * is a record of the following type:
+ */
+
+typedef struct TkToplevelFocusInfo {
+    TkWindow *topLevelPtr;	/* Information about top-level window. */
+    TkWindow *focusWinPtr;	/* The next time the focus comes to this
+				 * top-level, it will be given to this
+				 * window. */
+    struct TkToplevelFocusInfo *nextPtr;
+				/* Next in list of all toplevel focus records
+				 * for a given application. */
+} ToplevelFocusInfo;
+
+/*
+ * One of the following structures exists for each display used by
+ * each application.  These are linked together from the TkMainInfo
+ * structure.  These structures are needed because it isn't
+ * sufficient to store a single piece of focus information in each
+ * display or in each application: we need the cross-product.
+ * There needs to be separate information for each display, because
+ * it's possible to have multiple focus windows active simultaneously
+ * on different displays.  There also needs to be separate information
+ * for each application, because of embedding: if an embedded
+ * application has the focus, its container application also has
+ * the focus.  Thus we keep a list of structures for each application:
+ * the same display can appear in structures for several applications
+ * at once.
+ */
+
+typedef struct TkDisplayFocusInfo {
+    TkDisplay *dispPtr;		/* Display that this information pertains
+				 * to. */
+    struct TkWindow *focusWinPtr;
+				/* Window that currently has the focus for
+				 * this application on this display, or NULL
+				 * if none. */
+    struct TkWindow *focusOnMapPtr;
+				/* This points to a toplevel window that is
+				 * supposed to receive the X input focus as
+				 * soon as it is mapped (needed to handle the
+				 * fact that X won't allow the focus on an
+				 * unmapped window).  NULL means no delayed
+				 * focus op in progress for this display. */
+    int forceFocus;		/* Associated with focusOnMapPtr:  non-zero
+				 * means claim the focus even if some other
+				 * application currently has it. */
+    unsigned long focusSerial;	/* Serial number of last request this
+				 * application made to change the focus on
+				 * this display.  Used to identify stale
+				 * focus notifications coming from the
+				 * X server. */
+    struct TkDisplayFocusInfo *nextPtr;
+				/* Next in list of all display focus
+				 * records for a given application. */
+} DisplayFocusInfo;
+
+/*
+ * Global used for debugging.
+ */
+
+int tclFocusDebug = 0;
+
+/*
+ * The following magic value is stored in the "send_event" field of
+ * FocusIn and FocusOut events that are generated in this file.  This
+ * allows us to separate "real" events coming from the server from
+ * those that we generated.
+ */
+
+#define GENERATED_EVENT_MAGIC ((Bool) 0x547321ac)
+
+/*
+ * Forward declarations for procedures defined in this file:
+ */
+
+
+static DisplayFocusInfo *FindDisplayFocusInfo _ANSI_ARGS_((TkMainInfo *mainPtr,
+			    TkDisplay *dispPtr));
+static void		FocusMapProc _ANSI_ARGS_((ClientData clientData,
+			    XEvent *eventPtr));
+static void		GenerateFocusEvents _ANSI_ARGS_((TkWindow *sourcePtr,
+			    TkWindow *destPtr));
+static void		SetFocus _ANSI_ARGS_((TkWindow *winPtr, int force));
+
+/*
+ *--------------------------------------------------------------
+ *
+ * Tk_FocusCmd --
+ *
+ *	This procedure is invoked to process the "focus" Tcl command.
+ *	See the user documentation for details on what it does.
+ *
+ * Results:
+ *	A standard Tcl result.
+ *
+ * Side effects:
+ *	See the user documentation.
+ *
+ *--------------------------------------------------------------
+ */
+
+int
+Tk_FocusCmd(clientData, interp, argc, argv)
+    ClientData clientData;	/* Main window associated with
+				 * interpreter. */
+    Tcl_Interp *interp;		/* Current interpreter. */
+    int argc;			/* Number of arguments. */
+    char **argv;		/* Argument strings. */
+{
+    Tk_Window tkwin = (Tk_Window) clientData;
+    TkWindow *winPtr = (TkWindow *) clientData;
+    TkWindow *newPtr, *focusWinPtr, *topLevelPtr;
+    ToplevelFocusInfo *tlFocusPtr;
+    char c;
+    size_t length;
+
+    /*
+     * If invoked with no arguments, just return the current focus window.
+     */
+
+    if (argc == 1) {
+	focusWinPtr = TkGetFocusWin(winPtr);
+	if (focusWinPtr != NULL) {
+	    interp->result = focusWinPtr->pathName;
+	}
+	return TCL_OK;
+    }
+
+    /*
+     * If invoked with a single argument beginning with "." then focus
+     * on that window.
+     */
+
+    if (argc == 2) {
+	if (argv[1][0] == 0) {
+	    return TCL_OK;
+	}
+	if (argv[1][0] == '.') {
+	    newPtr = (TkWindow *) Tk_NameToWindow(interp, argv[1], tkwin);
+	    if (newPtr == NULL) {
+		return TCL_ERROR;
+	    }
+	    if (!(newPtr->flags & TK_ALREADY_DEAD)) {
+		SetFocus(newPtr, 0);
+	    }
+	    return TCL_OK;
+	}
+    }
+
+    length = strlen(argv[1]);
+    c = argv[1][1];
+    if ((c == 'd') && (strncmp(argv[1], "-displayof", length) == 0)) {
+	if (argc != 3) {
+	    Tcl_AppendResult(interp, "wrong # args: should be \"",
+		    argv[0], " -displayof window\"", (char *) NULL);
+	    return TCL_ERROR;
+	}
+	newPtr = (TkWindow *) Tk_NameToWindow(interp, argv[2], tkwin);
+	if (newPtr == NULL) {
+	    return TCL_ERROR;
+	}
+	newPtr = TkGetFocusWin(newPtr);
+	if (newPtr != NULL) {
+	    interp->result = newPtr->pathName;
+	}
+    } else if ((c == 'f') && (strncmp(argv[1], "-force", length) == 0)) {
+	if (argc != 3) {
+	    Tcl_AppendResult(interp, "wrong # args: should be \"",
+		    argv[0], " -force window\"", (char *) NULL);
+	    return TCL_ERROR;
+	}
+	if (argv[2][0] == 0) {
+	    return TCL_OK;
+	}
+	newPtr = (TkWindow *) Tk_NameToWindow(interp, argv[2], tkwin);
+	if (newPtr == NULL) {
+	    return TCL_ERROR;
+	}
+	SetFocus(newPtr, 1);
+    } else if ((c == 'l') && (strncmp(argv[1], "-lastfor", length) == 0)) {
+	if (argc != 3) {
+	    Tcl_AppendResult(interp, "wrong # args: should be \"",
+		    argv[0], " -lastfor window\"", (char *) NULL);
+	    return TCL_ERROR;
+	}
+	newPtr = (TkWindow *) Tk_NameToWindow(interp, argv[2], tkwin);
+	if (newPtr == NULL) {
+	    return TCL_ERROR;
+	}
+	for (topLevelPtr = newPtr; topLevelPtr != NULL;
+		topLevelPtr = topLevelPtr->parentPtr)  {
+	    if (topLevelPtr->flags & TK_TOP_LEVEL) {
+		for (tlFocusPtr = newPtr->mainPtr->tlFocusPtr;
+			tlFocusPtr != NULL;
+			tlFocusPtr = tlFocusPtr->nextPtr) {
+		    if (tlFocusPtr->topLevelPtr == topLevelPtr) {
+			interp->result = tlFocusPtr->focusWinPtr->pathName;
+			return TCL_OK;
+		    }
+		}
+		interp->result = topLevelPtr->pathName;
+		return TCL_OK;
+	    }
+	}
+    } else {
+	Tcl_AppendResult(interp, "bad option \"", argv[1],
+		"\": must be -displayof, -force, or -lastfor", (char *) NULL);
+	return TCL_ERROR;
+    }
+    return TCL_OK;
+}
+
+/*
+ *--------------------------------------------------------------
+ *
+ * TkFocusFilterEvent --
+ *
+ *	This procedure is invoked by Tk_HandleEvent when it encounters
+ *	a FocusIn, FocusOut, Enter, or Leave event.
+ *
+ * Results:
+ *	A return value of 1 means that Tk_HandleEvent should process
+ *	the event normally (i.e. event handlers should be invoked).
+ *	A return value of 0 means that this event should be ignored.
+ *
+ * Side effects:
+ *	Additional events may be generated, and the focus may switch.
+ *
+ *--------------------------------------------------------------
+ */
+
+int
+TkFocusFilterEvent(winPtr, eventPtr)
+    TkWindow *winPtr;		/* Window that focus event is directed to. */
+    XEvent *eventPtr;		/* FocusIn, FocusOut, Enter, or Leave
+				 * event. */
+{
+    /*
+     * Design notes: the window manager and X server work together to
+     * transfer the focus among top-level windows.  This procedure takes
+     * care of transferring the focus from a top-level or wrapper window
+     * to the actual window within that top-level that has the focus. 
+     * We do this by synthesizing X events to move the focus around. 
+     * None of the FocusIn and FocusOut events generated by X are ever
+     * used outside of this procedure;  only the synthesized events get
+     * through to the rest of the application.  At one point (e.g.
+     * Tk4.0b1) Tk used to call X to move the focus from a top-level to
+     * one of its descendants, then just pass through the events
+     * generated by X. This approach didn't work very well, for a
+     * variety of reasons. For example, if X generates the events they
+     * go at the back of the event queue, which could cause problems if
+     * other things have already happened, such as moving the focus to
+     * yet another window.
+     */
+
+    ToplevelFocusInfo *tlFocusPtr;
+    DisplayFocusInfo *displayFocusPtr;
+    TkDisplay *dispPtr = winPtr->dispPtr;
+    TkWindow *newFocusPtr;
+    int retValue, delta;
+
+    /*
+     * If this was a generated event, just turn off the generated
+     * flag and pass the event through to Tk bindings.
+     */
+
+    if (eventPtr->xfocus.send_event == GENERATED_EVENT_MAGIC) {
+	eventPtr->xfocus.send_event = 0;
+	return 1;
+    }
+
+    /*
+     * Check for special events generated by embedded applications to
+     * request the input focus.  If this is one of those events, make
+     * the change in focus and return without any additional processing
+     * of the event (note: the "detail" field of the event indicates
+     * whether to claim the focus even if we don't already have it).
+     */
+
+    if ((eventPtr->xfocus.mode == EMBEDDED_APP_WANTS_FOCUS)
+	    && (eventPtr->type == FocusIn)) {
+	SetFocus(winPtr, eventPtr->xfocus.detail);
+	return 0;
+    }
+
+    /*
+     * This was not a generated event.  We'll return 1 (so that the
+     * event will be processed) if it's an Enter or Leave event, and
+     * 0 (so that the event won't be processed) if it's a FocusIn or
+     * FocusOut event.
+     */
+
+    retValue = 0;
+    displayFocusPtr = FindDisplayFocusInfo(winPtr->mainPtr, winPtr->dispPtr);
+    if (eventPtr->type == FocusIn) {
+	/*
+	 * Skip FocusIn events that cause confusion
+	 * NotifyVirtual and NotifyNonlinearVirtual - Virtual events occur
+	 *	on windows in between the origin and destination of the
+	 *	focus change.  For FocusIn we may see this when focus
+	 *	goes into an embedded child.  We don't care about this,
+	 *	although we may end up getting a NotifyPointer later.
+	 * NotifyInferior - focus is coming to us from an embedded child.
+	 *	When focus is on an embeded focus, we still think we have
+	 *	the focus, too, so this message doesn't change our state.
+	 * NotifyPointerRoot - should never happen because this is sent
+	 *	to the root window.
+	 *
+	 * Interesting FocusIn events are
+	 * NotifyAncestor - focus is coming from our parent, probably the root.
+	 * NotifyNonlinear - focus is coming from a different branch, probably
+	 *	another toplevel.
+	 * NotifyPointer - implicit focus because of the mouse position.
+	 *	This is	only interesting on toplevels, when it means that the
+	 *	focus has been set to the root window but the mouse is over
+	 *	this toplevel.  We take the focus implicitly (probably no
+	 *	window manager)
+	 */
+
+	if ((eventPtr->xfocus.detail == NotifyVirtual)
+		|| (eventPtr->xfocus.detail == NotifyNonlinearVirtual)
+		|| (eventPtr->xfocus.detail == NotifyPointerRoot)
+		|| (eventPtr->xfocus.detail == NotifyInferior)) {
+	    return retValue;
+	}
+    } else if (eventPtr->type == FocusOut) {
+	/*
+	 * Skip FocusOut events that cause confusion.
+	 * NotifyPointer - the pointer is in us or a child, and we are losing
+	 *	focus because of an XSetInputFocus.  Other focus events
+	 *	will set our state properly.
+	 * NotifyPointerRoot - should never happen because this is sent
+	 *	to the root window.
+	 * NotifyInferior - focus leaving us for an embedded child.  We
+	 *	retain a notion of focus when an embedded child has focus.
+	 *
+	 * Interesting events are:
+	 * NotifyAncestor - focus is going to root.
+	 * NotifyNonlinear - focus is going to another branch, probably
+	 *	another toplevel.
+	 * NotifyVirtual, NotifyNonlinearVirtual - focus is passing through,
+	 *	and we need to make sure we track this.
+	 */
+
+	if ((eventPtr->xfocus.detail == NotifyPointer)
+		|| (eventPtr->xfocus.detail == NotifyPointerRoot)
+		|| (eventPtr->xfocus.detail == NotifyInferior)) {
+	    return retValue;
+	}
+    } else {
+	retValue = 1;
+	if (eventPtr->xcrossing.detail == NotifyInferior) {
+	    return retValue;
+	}
+    }
+
+    /*
+     * If winPtr isn't a top-level window than just ignore the event.
+     */
+
+    winPtr = TkWmFocusToplevel(winPtr);
+    if (winPtr == NULL) {
+	return retValue;
+    }
+
+    /*
+     * If there is a grab in effect and this window is outside the
+     * grabbed tree, then ignore the event.
+     */
+
+    if (TkGrabState(winPtr) == TK_GRAB_EXCLUDED)  {
+	return retValue;
+    }
+
+    /*
+     * It is possible that there were outstanding FocusIn and FocusOut
+     * events on their way to us at the time the focus was changed
+     * internally with the "focus" command.  If so, these events could
+     * potentially cause us to lose the focus (switch it to the window
+     * of the last FocusIn event) even though the focus change occurred
+     * after those events.  The following code detects this and ignores
+     * the stale events.
+     *
+     * Note: the focusSerial is only generated by TkpChangeFocus,
+     * whereas in Tk 4.2 there was always a nop marker generated.
+     */
+
+    delta = eventPtr->xfocus.serial - displayFocusPtr->focusSerial;
+    if (delta < 0) {
+	return retValue;
+    }
+
+    /*
+     * Find the ToplevelFocusInfo structure for the window, and make a new one
+     * if there isn't one already.
+     */
+
+    for (tlFocusPtr = winPtr->mainPtr->tlFocusPtr; tlFocusPtr != NULL;
+	    tlFocusPtr = tlFocusPtr->nextPtr) {
+	if (tlFocusPtr->topLevelPtr == winPtr) {
+	    break;
+	}
+    }
+    if (tlFocusPtr == NULL) {
+	tlFocusPtr = (ToplevelFocusInfo *) ckalloc(sizeof(ToplevelFocusInfo));
+	tlFocusPtr->topLevelPtr = tlFocusPtr->focusWinPtr = winPtr;
+	tlFocusPtr->nextPtr = winPtr->mainPtr->tlFocusPtr;
+	winPtr->mainPtr->tlFocusPtr = tlFocusPtr;
+    }
+    newFocusPtr = tlFocusPtr->focusWinPtr;
+
+    if (eventPtr->type == FocusIn) {
+	GenerateFocusEvents(displayFocusPtr->focusWinPtr, newFocusPtr);
+	displayFocusPtr->focusWinPtr = newFocusPtr;
+	dispPtr->focusPtr = newFocusPtr;
+
+	/*
+	 * NotifyPointer gets set when the focus has been set to the root window
+	 * but we have the pointer.  We'll treat this like an implicit
+	 * focus in event so that upon Leave events we release focus.
+	 */
+
+	if (!(winPtr->flags & TK_EMBEDDED)) {
+	    if (eventPtr->xfocus.detail == NotifyPointer) {
+		dispPtr->implicitWinPtr = winPtr;
+	    } else {
+		dispPtr->implicitWinPtr = NULL;
+	    }
+	}
+    } else if (eventPtr->type == FocusOut) {
+	GenerateFocusEvents(displayFocusPtr->focusWinPtr, (TkWindow *) NULL);
+
+	/*
+	 * Reset dispPtr->focusPtr, but only if it currently is the same
+	 * as this application's focusWinPtr: this check is needed to
+	 * handle embedded applications in the same process.
+	 */
+
+	if (dispPtr->focusPtr == displayFocusPtr->focusWinPtr) {
+	    dispPtr->focusPtr = NULL;
+	}
+	displayFocusPtr->focusWinPtr = NULL;
+    } else if (eventPtr->type == EnterNotify) {
+	/*
+	 * If there is no window manager, or if the window manager isn't
+	 * moving the focus around (e.g. the disgusting "NoTitleFocus"
+	 * option has been selected in twm), then we won't get FocusIn
+	 * or FocusOut events.  Instead, the "focus" field will be set
+	 * in an Enter event to indicate that we've already got the focus
+	 * when the mouse enters the window (even though we didn't get
+	 * a FocusIn event).  Watch for this and grab the focus when it
+	 * happens.  Note: if this is an embedded application then don't
+	 * accept the focus implicitly like this;  the container
+	 * application will give us the focus explicitly if it wants us
+	 * to have it.
+	 */
+
+	if (eventPtr->xcrossing.focus &&
+                (displayFocusPtr->focusWinPtr == NULL)
+		&& !(winPtr->flags & TK_EMBEDDED)) {
+	    if (tclFocusDebug) {
+		printf("Focussed implicitly on %s\n",
+			newFocusPtr->pathName);
+	    }
+
+	    GenerateFocusEvents(displayFocusPtr->focusWinPtr, newFocusPtr);
+	    displayFocusPtr->focusWinPtr = newFocusPtr;
+	    dispPtr->implicitWinPtr = winPtr;
+	    dispPtr->focusPtr = newFocusPtr;
+	}
+    } else if (eventPtr->type == LeaveNotify) {
+	/*
+	 * If the pointer just left a window for which we automatically
+	 * claimed the focus on enter, move the focus back to the root
+	 * window, where it was before we claimed it above.  Note:
+	 * dispPtr->implicitWinPtr may not be the same as
+	 * displayFocusPtr->focusWinPtr (e.g. because the "focus"
+	 * command was used to redirect the focus after it arrived at
+	 * dispPtr->implicitWinPtr)!!  In addition, we generate events
+	 * because the window manager won't give us a FocusOut event when
+	 * we focus on the root. 
+	 */
+
+	if ((dispPtr->implicitWinPtr != NULL)
+		&& !(winPtr->flags & TK_EMBEDDED)) {
+	    if (tclFocusDebug) {
+		printf("Defocussed implicit Async\n");
+	    }
+	    GenerateFocusEvents(displayFocusPtr->focusWinPtr,
+		    (TkWindow *) NULL);
+	    XSetInputFocus(dispPtr->display, PointerRoot, RevertToPointerRoot,
+		    CurrentTime);
+	    displayFocusPtr->focusWinPtr = NULL;
+	    dispPtr->implicitWinPtr = NULL;
+	}
+    }
+    return retValue;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * SetFocus --
+ *
+ *	This procedure is invoked to change the focus window for a
+ *	given display in a given application.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Event handlers may be invoked to process the change of
+ *	focus.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+SetFocus(winPtr, force)
+    TkWindow *winPtr;		/* Window that is to be the new focus for
+				 * its display and application. */
+    int force;			/* If non-zero, set the X focus to this
+				 * window even if the application doesn't
+				 * currently have the X focus. */
+{
+    ToplevelFocusInfo *tlFocusPtr;
+    DisplayFocusInfo *displayFocusPtr;
+    TkWindow *topLevelPtr;
+    int allMapped, serial;
+
+    displayFocusPtr = FindDisplayFocusInfo(winPtr->mainPtr, winPtr->dispPtr);
+    if (winPtr == displayFocusPtr->focusWinPtr) {
+	return;
+    }
+
+    /*
+     * Find the top-level window for winPtr, then find (or create)
+     * a record for the top-level.  Also see whether winPtr and all its
+     * ancestors are mapped.
+     */
+
+    allMapped = 1;
+    for (topLevelPtr = winPtr; ; topLevelPtr = topLevelPtr->parentPtr)  {
+	if (topLevelPtr == NULL) {
+	    /*
+	     * The window is being deleted.  No point in worrying about
+	     * giving it the focus.
+	     */
+	    return;
+	}
+	if (!(topLevelPtr->flags & TK_MAPPED)) {
+	    allMapped = 0;
+	}
+	if (topLevelPtr->flags & TK_TOP_LEVEL) {
+	    break;
+	}
+    }
+
+    /*
+     * If the new focus window isn't mapped, then we can't focus on it
+     * (X will generate an error, for example).  Instead, create an
+     * event handler that will set the focus to this window once it gets
+     * mapped.  At the same time, delete any old handler that might be
+     * around;  it's no longer relevant.
+     */
+
+    if (displayFocusPtr->focusOnMapPtr != NULL) {
+	Tk_DeleteEventHandler(
+		(Tk_Window) displayFocusPtr->focusOnMapPtr,
+		StructureNotifyMask, FocusMapProc,
+		(ClientData) displayFocusPtr->focusOnMapPtr);
+	displayFocusPtr->focusOnMapPtr = NULL;
+    }
+    if (!allMapped) {
+	Tk_CreateEventHandler((Tk_Window) winPtr,
+		VisibilityChangeMask, FocusMapProc,
+		(ClientData) winPtr);
+	displayFocusPtr->focusOnMapPtr = winPtr;
+	displayFocusPtr->forceFocus = force;
+	return;
+    }
+
+    for (tlFocusPtr = winPtr->mainPtr->tlFocusPtr; tlFocusPtr != NULL;
+	    tlFocusPtr = tlFocusPtr->nextPtr) {
+	if (tlFocusPtr->topLevelPtr == topLevelPtr) {
+	    break;
+	}
+    }
+    if (tlFocusPtr == NULL) {
+	tlFocusPtr = (ToplevelFocusInfo *) ckalloc(sizeof(ToplevelFocusInfo));
+	tlFocusPtr->topLevelPtr = topLevelPtr;
+	tlFocusPtr->nextPtr = winPtr->mainPtr->tlFocusPtr;
+	winPtr->mainPtr->tlFocusPtr = tlFocusPtr;
+    }
+    tlFocusPtr->focusWinPtr = winPtr;
+
+    /*
+     * Reset the window system's focus window and generate focus events,
+     * with two special cases:
+     *
+     * 1. If the application is embedded and doesn't currently have the
+     *    focus, don't set the focus directly.  Instead, see if the
+     *    embedding code can claim the focus from the enclosing
+     *    container.
+     * 2. Otherwise, if the application doesn't currently have the
+     *    focus, don't change the window system's focus unless it was
+     *    already in this application or "force" was specified.
+     */
+
+    if ((topLevelPtr->flags & TK_EMBEDDED)
+	    && (displayFocusPtr->focusWinPtr == NULL)) {
+	TkpClaimFocus(topLevelPtr, force);
+    } else if ((displayFocusPtr->focusWinPtr != NULL) || force) {
+	/*
+	 * Generate events to shift focus between Tk windows.
+	 * We do this regardless of what TkpChangeFocus does with
+	 * the real X focus so that Tk widgets track focus commands
+	 * when there is no window manager.  GenerateFocusEvents will
+	 * set up a serial number marker so we discard focus events
+	 * that are triggered by the ChangeFocus.
+	 */
+
+	serial = TkpChangeFocus(TkpGetWrapperWindow(topLevelPtr), force);
+	if (serial != 0) {
+	    displayFocusPtr->focusSerial = serial;
+	}
+	GenerateFocusEvents(displayFocusPtr->focusWinPtr, winPtr);
+	displayFocusPtr->focusWinPtr = winPtr;
+	winPtr->dispPtr->focusPtr = winPtr;
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TkGetFocusWin --
+ *
+ *	Given a window, this procedure returns the current focus
+ *	window for its application and display.
+ *
+ * Results:
+ *	The return value is a pointer to the window that currently
+ *	has the input focus for the specified application and
+ *	display, or NULL if none.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+TkWindow *
+TkGetFocusWin(winPtr)
+    TkWindow *winPtr;		/* Window that selects an application
+				 * and a display. */
+{
+    DisplayFocusInfo *displayFocusPtr;
+
+    if (winPtr == NULL) {
+	return (TkWindow *) NULL;
+    }
+
+    displayFocusPtr = FindDisplayFocusInfo(winPtr->mainPtr, winPtr->dispPtr);
+    return displayFocusPtr->focusWinPtr;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TkFocusKeyEvent --
+ *
+ *	Given a window and a key press or release event that arrived for
+ *	the window, use information about the keyboard focus to compute
+ *	which window should really get the event.  In addition, update
+ *	the event to refer to its new window.
+ *
+ * Results:
+ *	The return value is a pointer to the window that has the input
+ *	focus in winPtr's application, or NULL if winPtr's application
+ *	doesn't have the input focus.  If a non-NULL value is returned,
+ *	eventPtr will be updated to refer properly to the focus window.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+TkWindow *
+TkFocusKeyEvent(winPtr, eventPtr)
+    TkWindow *winPtr;		/* Window that selects an application
+				 * and a display. */
+    XEvent *eventPtr;		/* X event to redirect (should be KeyPress
+				 * or KeyRelease). */
+{
+    DisplayFocusInfo *displayFocusPtr;
+    TkWindow *focusWinPtr;
+    int focusX, focusY, vRootX, vRootY, vRootWidth, vRootHeight;
+
+    displayFocusPtr = FindDisplayFocusInfo(winPtr->mainPtr, winPtr->dispPtr);
+    focusWinPtr = displayFocusPtr->focusWinPtr;
+
+    /*
+     * The code below is a debugging aid to make sure that dispPtr->focusPtr
+     * is kept properly in sync with the "truth", which is the value in
+     * displayFocusPtr->focusWinPtr.
+     */
+
+#ifdef TCL_MEM_DEBUG
+    if (focusWinPtr != winPtr->dispPtr->focusPtr) {
+	printf("TkFocusKeyEvent found dispPtr->focusPtr out of sync:\n");
+	printf("expected %s, got %s\n",
+		(focusWinPtr != NULL) ? focusWinPtr->pathName : "??",
+		(winPtr->dispPtr->focusPtr != NULL) ?
+		winPtr->dispPtr->focusPtr->pathName : "??");
+    }
+#endif
+
+    if ((focusWinPtr != NULL) && (focusWinPtr->mainPtr == winPtr->mainPtr)) {
+	/*
+	 * Map the x and y coordinates to make sense in the context of
+	 * the focus window, if possible (make both -1 if the map-from
+	 * and map-to windows don't share the same screen).
+	 */
+
+	if ((focusWinPtr->display != winPtr->display)
+		|| (focusWinPtr->screenNum != winPtr->screenNum)) {
+	    eventPtr->xkey.x = -1;
+	    eventPtr->xkey.y = -1;
+	} else {
+	    Tk_GetVRootGeometry((Tk_Window) focusWinPtr, &vRootX, &vRootY,
+		    &vRootWidth, &vRootHeight);
+	    Tk_GetRootCoords((Tk_Window) focusWinPtr, &focusX, &focusY);
+	    eventPtr->xkey.x = eventPtr->xkey.x_root - vRootX - focusX;
+	    eventPtr->xkey.y = eventPtr->xkey.y_root - vRootY - focusY;
+	}
+	eventPtr->xkey.window = focusWinPtr->window;
+	return focusWinPtr;
+    }
+
+    /*
+     * The event doesn't belong to us.  Perhaps, due to embedding, it
+     * really belongs to someone else.  Give the embedding code a chance
+     * to redirect the event.
+     */
+
+    TkpRedirectKeyEvent(winPtr, eventPtr);
+    return (TkWindow *) NULL;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * TkFocusDeadWindow --
+ *
+ *	This procedure is invoked when it is determined that
+ *	a window is dead.  It cleans up focus-related information
+ *	about the window.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	Various things get cleaned up and recycled.
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+TkFocusDeadWindow(winPtr)
+    register TkWindow *winPtr;		/* Information about the window
+					 * that is being deleted. */
+{
+    ToplevelFocusInfo *tlFocusPtr, *prevPtr;
+    DisplayFocusInfo *displayFocusPtr;
+    TkDisplay *dispPtr = winPtr->dispPtr;
+
+    /*
+     * Search for focus records that refer to this window either as
+     * the top-level window or the current focus window.
+     */
+
+    displayFocusPtr = FindDisplayFocusInfo(winPtr->mainPtr, winPtr->dispPtr);
+    for (prevPtr = NULL, tlFocusPtr = winPtr->mainPtr->tlFocusPtr;
+	    tlFocusPtr != NULL;
+	    prevPtr = tlFocusPtr, tlFocusPtr = tlFocusPtr->nextPtr) {
+	if (winPtr == tlFocusPtr->topLevelPtr) {
+	    /*
+	     * The top-level window is the one being deleted: free
+	     * the focus record and release the focus back to PointerRoot
+	     * if we acquired it implicitly.
+	     */
+
+	    if (dispPtr->implicitWinPtr == winPtr) {
+		if (tclFocusDebug) {
+		    printf("releasing focus to root after %s died\n",
+			    tlFocusPtr->topLevelPtr->pathName);
+		}
+		dispPtr->implicitWinPtr = NULL;
+		displayFocusPtr->focusWinPtr = NULL;
+		dispPtr->focusPtr = NULL;
+	    }
+	    if (displayFocusPtr->focusWinPtr == tlFocusPtr->focusWinPtr) {
+		displayFocusPtr->focusWinPtr = NULL;
+		dispPtr->focusPtr = NULL;
+	    }
+	    if (prevPtr == NULL) {
+		winPtr->mainPtr->tlFocusPtr = tlFocusPtr->nextPtr;
+	    } else {
+		prevPtr->nextPtr = tlFocusPtr->nextPtr;
+	    }
+	    ckfree((char *) tlFocusPtr);
+	    break;
+	} else if (winPtr == tlFocusPtr->focusWinPtr) {
+	    /*
+	     * The deleted window had the focus for its top-level:
+	     * move the focus to the top-level itself.
+	     */
+
+	    tlFocusPtr->focusWinPtr = tlFocusPtr->topLevelPtr;
+	    if ((displayFocusPtr->focusWinPtr == winPtr)
+		    && !(tlFocusPtr->topLevelPtr->flags & TK_ALREADY_DEAD)) {
+		if (tclFocusDebug) {
+		    printf("forwarding focus to %s after %s died\n",
+			    tlFocusPtr->topLevelPtr->pathName,
+			    winPtr->pathName);
+		}
+		GenerateFocusEvents(displayFocusPtr->focusWinPtr,
+			tlFocusPtr->topLevelPtr);
+		displayFocusPtr->focusWinPtr = tlFocusPtr->topLevelPtr;
+		dispPtr->focusPtr = tlFocusPtr->topLevelPtr;
+	    }
+	    break;
+	}
+    }
+
+    if (displayFocusPtr->focusOnMapPtr == winPtr) {
+	displayFocusPtr->focusOnMapPtr = NULL;
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * GenerateFocusEvents --
+ *
+ *	This procedure is called to create FocusIn and FocusOut events to
+ *	move the input focus from one window to another.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	FocusIn and FocusOut events are generated.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+GenerateFocusEvents(sourcePtr, destPtr)
+    TkWindow *sourcePtr;	/* Window that used to have the focus (may
+				 * be NULL). */
+    TkWindow *destPtr;		/* New window to have the focus (may be
+				 * NULL). */
+
+{
+    XEvent event;
+    TkWindow *winPtr;
+
+    winPtr = sourcePtr;
+    if (winPtr == NULL) {
+	winPtr = destPtr;
+	if (winPtr == NULL) {
+	    return;
+	}
+    }
+
+    event.xfocus.serial = LastKnownRequestProcessed(winPtr->display);
+    event.xfocus.send_event = GENERATED_EVENT_MAGIC;
+    event.xfocus.display = winPtr->display;
+    event.xfocus.mode = NotifyNormal;
+    TkInOutEvents(&event, sourcePtr, destPtr, FocusOut, FocusIn,
+	    TCL_QUEUE_MARK);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * FocusMapProc --
+ *
+ *	This procedure is called as an event handler for VisibilityNotify
+ *	events, if a window receives the focus at a time when its
+ *	toplevel isn't mapped.  The procedure is needed because X
+ *	won't allow the focus to be set to an unmapped window;  we
+ *	detect when the toplevel is mapped and set the focus to it then.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	If this is a map event, the focus gets set to the toplevel
+ *	given by clientData.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+FocusMapProc(clientData, eventPtr)
+    ClientData clientData;	/* Toplevel window. */
+    XEvent *eventPtr;		/* Information about event. */
+{
+    TkWindow *winPtr = (TkWindow *) clientData;
+    DisplayFocusInfo *displayFocusPtr;
+
+    if (eventPtr->type == VisibilityNotify) {
+	displayFocusPtr = FindDisplayFocusInfo(winPtr->mainPtr,
+		winPtr->dispPtr);
+	if (tclFocusDebug) {
+	    printf("auto-focussing on %s, force %d\n", winPtr->pathName,
+		    displayFocusPtr->forceFocus);
+	}
+	Tk_DeleteEventHandler((Tk_Window) winPtr, VisibilityChangeMask,
+		FocusMapProc, clientData);
+	displayFocusPtr->focusOnMapPtr = NULL;
+	SetFocus(winPtr, displayFocusPtr->forceFocus);
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * FindDisplayFocusInfo --
+ *
+ *	Given an application and a display, this procedure locate the
+ *	focus record for that combination.  If no such record exists,
+ *	it creates a new record and initializes it.
+ *
+ * Results:
+ *	The return value is a pointer to the record.
+ *
+ * Side effects:
+ *	A new record will be allocated if there wasn't one already.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static DisplayFocusInfo *
+FindDisplayFocusInfo(mainPtr, dispPtr)
+    TkMainInfo *mainPtr;	/* Record that identifies a particular
+				 * application. */
+    TkDisplay *dispPtr;		/* Display whose focus information is
+				 * needed. */
+{
+    DisplayFocusInfo *displayFocusPtr;
+
+    for (displayFocusPtr = mainPtr->displayFocusPtr;
+	    displayFocusPtr != NULL;
+	    displayFocusPtr = displayFocusPtr->nextPtr) {
+	if (displayFocusPtr->dispPtr == dispPtr) {
+	    return displayFocusPtr;
+	}
+    }
+
+    /*
+     * The record doesn't exist yet.  Make a new one.
+     */
+
+    displayFocusPtr = (DisplayFocusInfo *) ckalloc(sizeof(DisplayFocusInfo));
+    displayFocusPtr->dispPtr = dispPtr;
+    displayFocusPtr->focusWinPtr = NULL;
+    displayFocusPtr->focusOnMapPtr = NULL;
+    displayFocusPtr->forceFocus = 0;
+    displayFocusPtr->focusSerial = 0;
+    displayFocusPtr->nextPtr = mainPtr->displayFocusPtr;
+    mainPtr->displayFocusPtr = displayFocusPtr;
+    return displayFocusPtr;
+}