tkgrab.c

linux系统下的音频通信

    TkDisplay *dispPtr = winPtr->dispPtr;

    if (dispPtr->eventualGrabWinPtr == winPtr) {
	/*
	 * Grab window was deleted.  Release the grab.
	 */

	Tk_Ungrab((Tk_Window) dispPtr->eventualGrabWinPtr);
    } else if (dispPtr->buttonWinPtr == winPtr) {
	ReleaseButtonGrab(dispPtr);
    }
    if (dispPtr->serverWinPtr == winPtr) {
	if (winPtr->flags & TK_TOP_LEVEL) {
	    dispPtr->serverWinPtr = NULL;
	} else {
	    dispPtr->serverWinPtr = winPtr->parentPtr;
	}
    }
    if (dispPtr->grabWinPtr == winPtr) {
	dispPtr->grabWinPtr = NULL;
    }
}

/*
 *----------------------------------------------------------------------
 *
 * EatGrabEvents --
 *
 *	This procedure is called to eliminate any Enter, Leave,
 *	FocusIn, or FocusOut events in the event queue for a
 *	display that have mode NotifyGrab or NotifyUngrab and
 *	have a serial number no less than a given value and are not
 *	generated by the grab module.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	DispPtr's display gets sync-ed, and some of the events get
 *	removed from the Tk event queue.
 *
 *----------------------------------------------------------------------
 */

static void
EatGrabEvents(dispPtr, serial)
    TkDisplay *dispPtr;		/* Display from which to consume events. */
    unsigned int serial;	/* Only discard events that have a serial
				 * number at least this great. */
{
    Tk_RestrictProc *oldProc;
    GrabInfo info;
    ClientData oldArg, dummy;

    info.display = dispPtr->display;
    info.serial = serial;
    TkpSync(info.display);
    oldProc = Tk_RestrictEvents(GrabRestrictProc, (ClientData)&info, &oldArg);
    while (Tcl_ServiceEvent(TCL_WINDOW_EVENTS)) {
    }
    Tk_RestrictEvents(oldProc, oldArg, &dummy);
}

/*
 *----------------------------------------------------------------------
 *
 * GrabRestrictProc --
 *
 *	A Tk_RestrictProc used by EatGrabEvents to eliminate any
 *	Enter, Leave, FocusIn, or FocusOut events in the event queue
 *	for a display that has mode NotifyGrab or NotifyUngrab and
 *	have a serial number no less than a given value.
 *
 * Results:
 *	Returns either TK_DISCARD_EVENT or TK_DEFER_EVENT.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static Tk_RestrictAction
GrabRestrictProc(arg, eventPtr)
    ClientData arg;
    XEvent *eventPtr;
{
    GrabInfo *info = (GrabInfo *) arg;
    int mode, diff;

    /*
     * The diff caculation is trickier than it may seem.  Don't forget
     * that serial numbers can wrap around, so can't compare the two
     * serial numbers directly.
     */

    diff = eventPtr->xany.serial - info->serial;
    if ((eventPtr->type == EnterNotify)
	    || (eventPtr->type == LeaveNotify)) {
	mode = eventPtr->xcrossing.mode;
    } else if ((eventPtr->type == FocusIn)
	    || (eventPtr->type == FocusOut)) {
	mode = eventPtr->xfocus.mode;
    } else {
	mode = NotifyNormal;
    }
    if ((info->display != eventPtr->xany.display) || (mode == NotifyNormal)
	    || (diff < 0)) {
	return TK_DEFER_EVENT;
    } else {
	return TK_DISCARD_EVENT;
    }
}

/*
 *----------------------------------------------------------------------
 *
 * QueueGrabWindowChange --
 *
 *	This procedure queues a special event in the Tcl event queue,
 *	which will cause the "grabWinPtr" field for the display to get
 *	modified when the event is processed.  This is needed to make
 *	sure that the grab window changes at the proper time relative
 *	to grab-related enter and leave events that are also in the
 *	queue.  In particular, this approach works even when multiple
 *	grabs and ungrabs happen back-to-back.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	DispPtr->grabWinPtr will be modified later (by GrabWinEventProc)
 *	when the event is removed from the grab event queue.
 *
 *----------------------------------------------------------------------
 */

static void
QueueGrabWindowChange(dispPtr, grabWinPtr)
    TkDisplay *dispPtr;		/* Display on which to change the grab
				 * window. */
    TkWindow *grabWinPtr;	/* Window that is to become the new grab
				 * window (may be NULL). */
{
    NewGrabWinEvent *grabEvPtr;

    grabEvPtr = (NewGrabWinEvent *) ckalloc(sizeof(NewGrabWinEvent));
    grabEvPtr->header.proc = GrabWinEventProc;
    grabEvPtr->dispPtr = dispPtr;
    if (grabWinPtr == NULL) {
	grabEvPtr->grabWindow = None;
    } else {
	grabEvPtr->grabWindow = grabWinPtr->window;
    }
    Tcl_QueueEvent(&grabEvPtr->header, TCL_QUEUE_MARK);
    dispPtr->eventualGrabWinPtr = grabWinPtr;
}

/*
 *----------------------------------------------------------------------
 *
 * GrabWinEventProc --
 *
 *	This procedure is invoked as a handler for Tcl_Events of type
 *	NewGrabWinEvent.  It updates the current grab window field in
 *	a display.
 *
 * Results:
 *	Returns 1 if the event was processed, 0 if it should be deferred
 *	for processing later.
 *
 * Side effects:
 *	The grabWinPtr field is modified in the display associated with
 *	the event.
 *
 *----------------------------------------------------------------------
 */

static int
GrabWinEventProc(evPtr, flags)
    Tcl_Event *evPtr;		/* Event of type NewGrabWinEvent. */
    int flags;			/* Flags argument to Tk_DoOneEvent: indicates
				 * what kinds of events are being processed
				 * right now. */
{
    NewGrabWinEvent *grabEvPtr = (NewGrabWinEvent *) evPtr;

    grabEvPtr->dispPtr->grabWinPtr = (TkWindow *) Tk_IdToWindow(
	    grabEvPtr->dispPtr->display, grabEvPtr->grabWindow);
    return 1;
}

/*
 *----------------------------------------------------------------------
 *
 * FindCommonAncestor --
 *
 *	Given two windows, this procedure finds their least common
 *	ancestor and also computes how many levels up this ancestor
 *	is from each of the original windows.
 *
 * Results:
 *	If the windows are in different applications or top-level
 *	windows, then NULL is returned and *countPtr1 and *countPtr2
 *	are set to the depths of the two windows in their respective
 *	top-level windows (1 means the window is a top-level, 2 means
 *	its parent is a top-level, and so on).  Otherwise, the return
 *	value is a pointer to the common ancestor and the counts are
 *	set to the distance of winPtr1 and winPtr2 from this ancestor
 *	(1 means they're children, 2 means grand-children, etc.).
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static TkWindow *
FindCommonAncestor(winPtr1, winPtr2, countPtr1, countPtr2)
    TkWindow *winPtr1;		/* First window.   May be NULL. */
    TkWindow *winPtr2;		/* Second window.  May be NULL. */
    int *countPtr1;		/* Store nesting level of winPtr1 within
				 * common ancestor here. */
    int *countPtr2;		/* Store nesting level of winPtr2 within
				 * common ancestor here. */
{
    register TkWindow *winPtr;
    TkWindow *ancestorPtr;
    int count1, count2, i;

    /*
     * Mark winPtr1 and all of its ancestors with a special flag bit.
     */

    if (winPtr1 != NULL) {
	for (winPtr = winPtr1; winPtr != NULL; winPtr = winPtr->parentPtr) {
	    winPtr->flags |= TK_GRAB_FLAG;
	    if (winPtr->flags & TK_TOP_LEVEL) {
		break;
	    }
	}
    }

    /*
     * Search upwards from winPtr2 until an ancestor of winPtr1 is
     * found or a top-level window is reached.
     */

    winPtr = winPtr2;
    count2 = 0;
    ancestorPtr = NULL;
    if (winPtr2 != NULL) {
	for (; winPtr != NULL; count2++, winPtr = winPtr->parentPtr) {
	    if (winPtr->flags & TK_GRAB_FLAG) {
		ancestorPtr = winPtr;
		break;
	    }
	    if (winPtr->flags & TK_TOP_LEVEL)  {
		count2++;
		break;
	    }
	}
    }

    /*
     * Search upwards from winPtr1 again, clearing the flag bits and
     * remembering how many levels up we had to go.
     */

    if (winPtr1 == NULL) {
	count1 = 0;
    } else {
	count1 = -1;
	for (i = 0, winPtr = winPtr1; winPtr != NULL;
		i++, winPtr = winPtr->parentPtr) {
	    winPtr->flags &= ~TK_GRAB_FLAG;
	    if (winPtr == ancestorPtr) {
		count1 = i;
	    }
	    if (winPtr->flags & TK_TOP_LEVEL) {
		if (count1 == -1) {
		    count1 = i+1;
		}
		break;
	    }
	}
    }

    *countPtr1 = count1;
    *countPtr2 = count2;
    return ancestorPtr;
}

/*
 *----------------------------------------------------------------------
 *
 * TkPositionInTree --
 *
 *	Compute where the given window is relative to a particular
 *	subtree of the window hierarchy.
 *
 * Results:
 *
 *	Returns TK_GRAB_IN_TREE if the window is contained in the
 *	subtree.  Returns TK_GRAB_ANCESTOR if the window is an
 *	ancestor of the subtree, in the same toplevel.  Otherwise
 *	it returns TK_GRAB_EXCLUDED.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

int
TkPositionInTree(winPtr, treePtr)
    TkWindow *winPtr;		/* Window to be checked. */
    TkWindow *treePtr;		/* Root of tree to compare against. */
{
    TkWindow *winPtr2;

    for (winPtr2 = winPtr; winPtr2 != treePtr;
	   winPtr2 = winPtr2->parentPtr) {
	if (winPtr2 == NULL) {
	    for (winPtr2 = treePtr; winPtr2 != NULL;
		    winPtr2 = winPtr2->parentPtr) {
		if (winPtr2 == winPtr) {
		    return TK_GRAB_ANCESTOR;
		}
		if (winPtr2->flags & TK_TOP_LEVEL) {
		    break;
		}
	    }
	    return TK_GRAB_EXCLUDED;
	}
    }
    return TK_GRAB_IN_TREE;
}

/*
 *----------------------------------------------------------------------
 *
 * TkGrabState --
 *
 *	Given a window, this procedure returns a value that indicates
 *	the grab state of the application relative to the window.
 *
 * Results:
 *	The return value is one of three things:
 *	    TK_GRAB_NONE -	no grab is in effect.
 *	    TK_GRAB_IN_TREE -   there is a grab in effect, and winPtr
 *				is in the grabbed subtree.
 *	    TK_GRAB_ANCESTOR -  there is a grab in effect;  winPtr is
 *				an ancestor of the grabbed window, in
 *				the same toplevel.
 *	    TK_GRAB_EXCLUDED -	there is a grab in effect; winPtr is
 *				outside the tree of the grab and is not
 *				an ancestor of the grabbed window in the
 *				same toplevel.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

int
TkGrabState(winPtr)
    TkWindow *winPtr;		/* Window for which grab information is
				 * needed. */
{
    TkWindow *grabWinPtr = winPtr->dispPtr->grabWinPtr;

    if (grabWinPtr == NULL) {
	return TK_GRAB_NONE;
    }
    if ((winPtr->mainPtr != grabWinPtr->mainPtr)
	    && !(winPtr->dispPtr->grabFlags & GRAB_GLOBAL)) {
	return TK_GRAB_NONE;
    }

    return TkPositionInTree(winPtr, grabWinPtr);
}