tkgrab.c

linux系统下的音频通信

/* 
 * tkGrab.c --
 *
 *	This file provides procedures that implement grabs for Tk.
 *
 * Copyright (c) 1992-1994 The Regents of the University of California.
 * Copyright (c) 1994-1995 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: @(#) tkGrab.c 1.52 97/03/21 11:14:34
 */

#include "tkPort.h"
#include "tkInt.h"

/*
 * The grab state machine has four states: ungrabbed, button pressed,
 * grabbed, and button pressed while grabbed.  In addition, there are
 * three pieces of grab state information: the current grab window,
 * the current restrict window, and whether the mouse is captured.
 *
 * The current grab window specifies the point in the Tk window
 * heirarchy above which pointer events will not be reported.  Any
 * window within the subtree below the grab window will continue to
 * receive events as normal.  Events outside of the grab tree will be
 * reported to the grab window.
 *
 * If the current restrict window is set, then all pointer events will
 * be reported only to the restrict window.  The restrict window is
 * normally set during an automatic button grab.
 *
 * The mouse capture state specifies whether the window system will
 * report mouse events outside of any Tk toplevels.  This is set
 * during a global grab or an automatic button grab.
 *
 * The transitions between different states is given in the following
 * table:
 * 
 * Event\State	U	B	G	GB
 * -----------	--	--	--	--
 * FirstPress	B	B	GB	GB
 * Press	B	B	G	GB
 * Release	U	B	G	GB
 * LastRelease	U	U	G	G
 * Grab		G	G	G	G
 * Ungrab	U	B	U	U
 *
 * Note: U=Ungrabbed, B=Button, G=Grabbed, GB=Grab and Button
 *
 * In addition, the following conditions are always true:
 *
 * State\Variable	Grab	     Restrict	     Capture
 * --------------	----	     --------	     -------
 * Ungrabbed		 0		0		0
 * Button		 0		1		1
 * Grabbed		 1		0		b/g
 * Grab and Button	 1		1		1
 *
 * Note: 0 means variable is set to NULL, 1 means variable is set to
 * some window, b/g means the variable is set to a window if a button
 * is currently down or a global grab is in effect.
 *
 * The final complication to all of this is enter and leave events.
 * In order to correctly handle all of the various cases, Tk cannot
 * rely on X enter/leave events in all situations.  The following
 * describes the correct sequence of enter and leave events that
 * should be observed by Tk scripts:
 *
 * Event(state)		Enter/Leave From -> To
 * ------------		----------------------
 * LastRelease(B | GB): restrict window -> anc(grab window, event window)
 * Grab(U | B): 	event window -> anc(grab window, event window)
 * Grab(G):		anc(old grab window, event window) ->
 * 				anc(new grab window, event window)
 * Grab(GB):		restrict window -> anc(new grab window, event window)
 * Ungrab(G):		anc(grab window, event window) -> event window
 * Ungrab(GB):		restrict window -> event window
 *
 * Note: anc(x,y) returns the least ancestor of y that is in the tree
 * of x, terminating at toplevels.
 */

/*
 * The following structure is used to pass information to 
 * GrabRestrictProc from EatGrabEvents.
 */

typedef struct {
    Display *display;		/* Display from which to discard events. */
    unsigned int serial;	/* Serial number with which to compare. */
} GrabInfo;

/*
 * Bit definitions for grabFlags field of TkDisplay structures:
 *
 * GRAB_GLOBAL			1 means this is a global grab (we grabbed via
 *				the server so all applications are locked out).
 *				0 means this is a local grab that affects
 *				only this application.
 * GRAB_TEMP_GLOBAL		1 means we've temporarily grabbed via the
 *				server because a button is down and we want
 *				to make sure that we get the button-up
 *				event.  The grab will be released when the
 *				last mouse button goes up.
 */

#define GRAB_GLOBAL		1
#define GRAB_TEMP_GLOBAL	4

/*
 * The following structure is a Tcl_Event that triggers a change in
 * the grabWinPtr field of a display.  This event guarantees that
 * the change occurs in the proper order relative to enter and leave
 * events.
 */

typedef struct NewGrabWinEvent {
    Tcl_Event header;		/* Standard information for all Tcl events. */
    TkDisplay *dispPtr;		/* Display whose grab window is to change. */
    Window grabWindow;		/* New grab window for display.  This is
				 * recorded instead of a (TkWindow *) because
				 * it will allow us to detect cases where
				 * the window is destroyed before this event
				 * is processed. */
} NewGrabWinEvent;

/*
 * The following magic value is stored in the "send_event" field of
 * EnterNotify and LeaveNotify 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) 0x147321ac)

/*
 * Mask that selects any of the state bits corresponding to buttons,
 * plus masks that select individual buttons' bits:
 */

#define ALL_BUTTONS \
	(Button1Mask|Button2Mask|Button3Mask|Button4Mask|Button5Mask)
static unsigned int buttonStates[] = {
    Button1Mask, Button2Mask, Button3Mask, Button4Mask, Button5Mask
};

/*
 * Forward declarations for procedures declared later in this file:
 */

static void		EatGrabEvents _ANSI_ARGS_((TkDisplay *dispPtr,
			    unsigned int serial));
static TkWindow *	FindCommonAncestor _ANSI_ARGS_((TkWindow *winPtr1,
			    TkWindow *winPtr2, int *countPtr1,
			    int *countPtr2));
static Tk_RestrictAction GrabRestrictProc _ANSI_ARGS_((ClientData arg,
			    XEvent *eventPtr));
static int		GrabWinEventProc _ANSI_ARGS_((Tcl_Event *evPtr,
			    int flags));
static void		MovePointer2 _ANSI_ARGS_((TkWindow *sourcePtr,
			    TkWindow *destPtr, int mode, int leaveEvents,
			    int EnterEvents));
static void		QueueGrabWindowChange _ANSI_ARGS_((TkDisplay *dispPtr,
			    TkWindow *grabWinPtr));
static void		ReleaseButtonGrab _ANSI_ARGS_((TkDisplay *dispPtr));

/*
 *----------------------------------------------------------------------
 *
 * Tk_GrabCmd --
 *
 *	This procedure is invoked to process the "grab" Tcl command.
 *	See the user documentation for details on what it does.
 *
 * Results:
 *	A standard Tcl result.
 *
 * Side effects:
 *	See the user documentation.
 *
 *----------------------------------------------------------------------
 */

	/* ARGSUSED */
int
Tk_GrabCmd(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. */
{
    int globalGrab, c;
    Tk_Window tkwin;
    TkDisplay *dispPtr;
    size_t length;

    if (argc < 2) {
	badArgs:
	Tcl_AppendResult(interp, "wrong # args: should be \"",
		argv[0], " ?-global? window\" or \"", argv[0],
		" option ?arg arg ...?\"", (char *) NULL);
	return TCL_ERROR;
    }
    c = argv[1][0];
    length = strlen(argv[1]);
    if (c == '.') {
	if (argc != 2) {
	    goto badArgs;
	}
	tkwin = Tk_NameToWindow(interp, argv[1], (Tk_Window) clientData);
	if (tkwin == NULL) {
	    return TCL_ERROR;
	}
	return Tk_Grab(interp, tkwin, 0);
    } else if ((c == '-') && (strncmp(argv[1], "-global", length) == 0)
	    && (length >= 2)) {
	if (argc != 3) {
	    goto badArgs;
	}
	tkwin = Tk_NameToWindow(interp, argv[2], (Tk_Window) clientData);
	if (tkwin == NULL) {
	    return TCL_ERROR;
	}
	return Tk_Grab(interp, tkwin, 1);
    } else if ((c == 'c') && (strncmp(argv[1], "current", length) == 0)) {
	if (argc > 3) {
	    Tcl_AppendResult(interp, "wrong # args: should be \"",
		    argv[0], " current ?window?\"", (char *) NULL);
	    return TCL_ERROR;
	}
	if (argc == 3) {
	    tkwin = Tk_NameToWindow(interp, argv[2], (Tk_Window) clientData);
	    if (tkwin == NULL) {
		return TCL_ERROR;
	    }
	    dispPtr = ((TkWindow *) tkwin)->dispPtr;
	    if (dispPtr->eventualGrabWinPtr != NULL) {
		interp->result = dispPtr->eventualGrabWinPtr->pathName;
	    }
	} else {
	    for (dispPtr = tkDisplayList; dispPtr != NULL;
		    dispPtr = dispPtr->nextPtr) {
		if (dispPtr->eventualGrabWinPtr != NULL) {
		    Tcl_AppendElement(interp,
			    dispPtr->eventualGrabWinPtr->pathName);
		}
	    }
	}
	return TCL_OK;
    } else if ((c == 'r') && (strncmp(argv[1], "release", length) == 0)) {
	if (argc != 3) {
	    Tcl_AppendResult(interp, "wrong # args: should be \"",
		    argv[0], " release window\"", (char *) NULL);
	    return TCL_ERROR;
	}
	tkwin = Tk_NameToWindow(interp, argv[2], (Tk_Window) clientData);
	if (tkwin == NULL) {
	    Tcl_ResetResult(interp);
	} else {
	    Tk_Ungrab(tkwin);
	}
    } else if ((c == 's') && (strncmp(argv[1], "set", length) == 0)
	    && (length >= 2)) {
	if ((argc != 3) && (argc != 4)) {
	    Tcl_AppendResult(interp, "wrong # args: should be \"",
		    argv[0], " set ?-global? window\"", (char *) NULL);
	    return TCL_ERROR;
	}
	if (argc == 3) {
	    globalGrab = 0;
	    tkwin = Tk_NameToWindow(interp, argv[2], (Tk_Window) clientData);
	} else {
	    globalGrab = 1;
	    length = strlen(argv[2]);
	    if ((strncmp(argv[2], "-global", length) != 0) || (length < 2)) {
		Tcl_AppendResult(interp, "bad argument \"", argv[2],
			"\": must be \"", argv[0], " set ?-global? window\"",
			(char *) NULL);
		return TCL_ERROR;
	    }
	    tkwin = Tk_NameToWindow(interp, argv[3], (Tk_Window) clientData);
	}
	if (tkwin == NULL) {
	    return TCL_ERROR;
	}
	return Tk_Grab(interp, tkwin, globalGrab);
    } else if ((c == 's') && (strncmp(argv[1], "status", length) == 0)
	    && (length >= 2)) {
	TkWindow *winPtr;

	if (argc != 3) {
	    Tcl_AppendResult(interp, "wrong # args: should be \"",
		    argv[0], " status window\"", (char *) NULL);
	    return TCL_ERROR;
	}
	winPtr = (TkWindow *) Tk_NameToWindow(interp, argv[2],
		(Tk_Window) clientData);
	if (winPtr == NULL) {
	    return TCL_ERROR;
	}
	dispPtr = winPtr->dispPtr;
	if (dispPtr->eventualGrabWinPtr != winPtr) {
	    interp->result = "none";
	} else if (dispPtr->grabFlags & GRAB_GLOBAL) {
	    interp->result = "global";
	} else {
	    interp->result = "local";
	}
    } else {
	Tcl_AppendResult(interp, "unknown or ambiguous option \"", argv[1],
		"\": must be current, release, set, or status",
		(char *) NULL);
	return TCL_ERROR;
    }
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * Tk_Grab --
 *
 *	Grabs the pointer and keyboard, so that mouse-related events are
 *	only reported relative to a given window and its descendants.
 *
 * Results:
 *	A standard Tcl result is returned.  TCL_OK is the normal return
 *	value;  if the grab could not be set then TCL_ERROR is returned
 *	and interp->result will hold an error message.
 *
 * Side effects:
 *	Once this call completes successfully, no window outside the
 *	tree rooted at tkwin will receive pointer- or keyboard-related
 *	events until the next call to Tk_Ungrab.  If a previous grab was
 *	in effect within this application, then it is replaced with a new
 *	one.
 *
 *----------------------------------------------------------------------
 */

int
Tk_Grab(interp, tkwin, grabGlobal)
    Tcl_Interp *interp;			/* Used for error reporting. */
    Tk_Window tkwin;			/* Window on whose behalf the pointer
					 * is to be grabbed. */
    int grabGlobal;			/* Non-zero means issue a grab to the
					 * server so that no other application
					 * gets mouse or keyboard events.
					 * Zero means the grab only applies
					 * within this application. */
{
    int grabResult, numTries;
    TkWindow *winPtr = (TkWindow *) tkwin;
    TkDisplay *dispPtr = winPtr->dispPtr;
    TkWindow *winPtr2;
    unsigned int serial;

    ReleaseButtonGrab(dispPtr);
    if (dispPtr->eventualGrabWinPtr != NULL) {
	if ((dispPtr->eventualGrabWinPtr == winPtr)
		&& (grabGlobal == ((dispPtr->grabFlags & GRAB_GLOBAL) != 0))) {
	    return TCL_OK;
	}
	if (dispPtr->eventualGrabWinPtr->mainPtr != winPtr->mainPtr) {
	    alreadyGrabbed:
	    interp->result = "grab failed: another application has grab";
	    return TCL_ERROR;
	}
	Tk_Ungrab((Tk_Window) dispPtr->eventualGrabWinPtr);
    }

    Tk_MakeWindowExist(tkwin);
    if (!grabGlobal) {
	Window dummy1, dummy2;
	int dummy3, dummy4, dummy5, dummy6;
	unsigned int state;

	/*
	 * Local grab.  However, if any mouse buttons are down, turn
	 * it into a global grab temporarily, until the last button
	 * goes up.  This does two things: (a) it makes sure that we