tkfocus.c

linux系统下的音频通信

/* 
 * 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