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/*

 * tkUnixEvent.c --

 *

 *      This file implements an event source for X displays for the

 *      UNIX version of Tk.

 *

 * Copyright (c) 1995-1997 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: tkUnixEvent.c,v 1.1.1.1 2002-01-16 10:26:01 markom Exp $

 */

#include "tkInt.h"

#include "tkUnixInt.h"

#include <signal.h>

/*

 * The following static indicates whether this module has been initialized.

 */

static int initialized = 0;

/*

 * Prototypes for procedures that are referenced only in this file:

 */

static void             DisplayCheckProc _ANSI_ARGS_((ClientData clientData,

                            int flags));

static void             DisplayExitHandler _ANSI_ARGS_((

                            ClientData clientData));

static void             DisplayFileProc _ANSI_ARGS_((ClientData clientData,

                            int flags));

static void             DisplaySetupProc _ANSI_ARGS_((ClientData clientData,

                            int flags));

/*

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

 *

 * TkCreateXEventSource --

 *

 *      This procedure is called during Tk initialization to create

 *      the event source for X Window events.

 *

 * Results:

 *      None.

 *

 * Side effects:

 *      A new event source is created.

 *

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

 */

void

TkCreateXEventSource()

{

    if (!initialized) {

        initialized = 1;

        Tcl_CreateEventSource(DisplaySetupProc, DisplayCheckProc, NULL);

        Tcl_CreateExitHandler(DisplayExitHandler, NULL);

    }

}

/*

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

 *

 * DisplayExitHandler --

 *

 *      This function is called during finalization to clean up the

 *      display module.

 *

 * Results:

 *      None.

 *

 * Side effects:

 *      None.

 *

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

 */

static void

DisplayExitHandler(clientData)

    ClientData clientData;      /* Not used. */

{

    Tcl_DeleteEventSource(DisplaySetupProc, DisplayCheckProc, NULL);

    initialized = 0;

}

/*

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

 *

 * TkpOpenDisplay --

 *

 *      Allocates a new TkDisplay, opens the X display, and establishes

 *      the file handler for the connection.

 *

 * Results:

 *      A pointer to a Tk display structure.

 *

 * Side effects:

 *      Opens a display.

 *

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

 */

TkDisplay *

TkpOpenDisplay(display_name)

    char *display_name;

{

    TkDisplay *dispPtr;

    Display *display = XOpenDisplay(display_name);

    if (display == NULL) {

        return NULL;

    }

    dispPtr = (TkDisplay *) ckalloc(sizeof(TkDisplay));

    dispPtr->display = display;

    Tcl_CreateFileHandler(ConnectionNumber(display), TCL_READABLE,

            DisplayFileProc, (ClientData) dispPtr);

    return dispPtr;

}

/*

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

 *

 * TkpCloseDisplay --

 *

 *      Cancels notifier callbacks and closes a display.

 *

 * Results:

 *      None.

 *

 * Side effects:

 *      Deallocates the displayPtr.

 *

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

 */

void

TkpCloseDisplay(displayPtr)

    TkDisplay *displayPtr;

{

    TkDisplay *dispPtr = (TkDisplay *) displayPtr;

    if (dispPtr->display != 0) {

        Tcl_DeleteFileHandler(ConnectionNumber(dispPtr->display));

        (void) XSync(dispPtr->display, False);

        (void) XCloseDisplay(dispPtr->display);

    }

    ckfree((char *) dispPtr);

}

/*

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

 *

 * DisplaySetupProc --

 *

 *      This procedure implements the setup part of the UNIX X display

 *      event source.  It is invoked by Tcl_DoOneEvent before entering

 *      the notifier to check for events on all displays.

 *

 * Results:

 *      None.

 *

 * Side effects:

 *      If data is queued on a display inside Xlib, then the maximum

 *      block time will be set to 0 to ensure that the notifier returns

 *      control to Tcl even if there is no more data on the X connection.

 *

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

 */

static void

DisplaySetupProc(clientData, flags)

    ClientData clientData;      /* Not used. */

    int flags;

{

    TkDisplay *dispPtr;

    static Tcl_Time blockTime = { 0, 0 };

    if (!(flags & TCL_WINDOW_EVENTS)) {

        return;

    }

    for (dispPtr = tkDisplayList; dispPtr != NULL;

         dispPtr = dispPtr->nextPtr) {

        /*

         * Flush the display. If data is pending on the X queue, set

         * the block time to zero.  This ensures that we won't block

         * in the notifier if there is data in the X queue, but not on

         * the server socket.

         */

        XFlush(dispPtr->display);

        if (XQLength(dispPtr->display) > 0) {

            Tcl_SetMaxBlockTime(&blockTime);

        }

    }

}

/*

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

 *

 * DisplayCheckProc --

 *

 *      This procedure checks for events sitting in the X event

 *      queue.

 *

 * Results:

 *      None.

 *

 * Side effects:

 *      Moves queued events onto the Tcl event queue.

 *

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

 */

static void

DisplayCheckProc(clientData, flags)

    ClientData clientData;      /* Not used. */

    int flags;

{

    TkDisplay *dispPtr;

    XEvent event;

    int numFound;

    if (!(flags & TCL_WINDOW_EVENTS)) {

        return;

    }

    for (dispPtr = tkDisplayList; dispPtr != NULL;

         dispPtr = dispPtr->nextPtr) {

        XFlush(dispPtr->display);

        numFound = XQLength(dispPtr->display);

        /*

         * Transfer events from the X event queue to the Tk event queue.

         */

        while (numFound > 0) {

            XNextEvent(dispPtr->display, &event);

            Tk_QueueWindowEvent(&event, TCL_QUEUE_TAIL);

            numFound--;

        }

    }

}

/*

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

 *

 * DisplayFileProc --

 *

 *      This procedure implements the file handler for the X connection.

 *

 * Results:

 *      None.

 *

 * Side effects:

 *      Makes entries on the Tcl event queue for all the events available

 *      from all the displays.

 *

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

 */

static void

DisplayFileProc(clientData, flags)

    ClientData clientData;              /* The display pointer. */

    int flags;                          /* Should be TCL_READABLE. */

{

    TkDisplay *dispPtr = (TkDisplay *) clientData;

    Display *display = dispPtr->display;

    XEvent event;

    int numFound;

    XFlush(display);

    numFound = XEventsQueued(display, QueuedAfterReading);

    if (numFound == 0) {

        /*

         * Things are very tricky if there aren't any events readable

         * at this point (after all, there was supposedly data

         * available on the connection).  A couple of things could

         * have occurred:

         *

         * One possibility is that there were only error events in the

         * input from the server.  If this happens, we should return

         * (we don't want to go to sleep in XNextEvent below, since

         * this would block out other sources of input to the

         * process).

         *

         * Another possibility is that our connection to the server

         * has been closed.  This will not necessarily be detected in

         * XEventsQueued (!!), so if we just return then there will be

         * an infinite loop.  To detect such an error, generate a NoOp

         * protocol request to exercise the connection to the server,

         * then return.  However, must disable SIGPIPE while sending

         * the request, or else the process will die from the signal

         * and won't invoke the X error function to print a nice (?!)

         * message.

         */

        void (*oldHandler)();

        oldHandler = (void (*)()) signal(SIGPIPE, SIG_IGN);

        XNoOp(display);

        XFlush(display);

        (void) signal(SIGPIPE, oldHandler);

    }

    /*

     * Transfer events from the X event queue to the Tk event queue.

     */

    while (numFound > 0) {

        XNextEvent(display, &event);

        Tk_QueueWindowEvent(&event, TCL_QUEUE_TAIL);

        numFound--;

    }

}

/*

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

 *

 * TkUnixDoOneXEvent --

 *

 *      This routine waits for an X event to be processed or for

 *      a timeout to occur.  The timeout is specified as an absolute

 *      time.  This routine is called when Tk needs to wait for a

 *      particular X event without letting arbitrary events be

 *      processed.  The caller will typically call Tk_RestrictEvents

 *      to set up an event filter before calling this routine.  This

 *      routine will service at most one event per invocation.

 *

 * Results:

 *      Returns 0 if the timeout has expired, otherwise returns 1.

 *

 * Side effects:

 *      Can invoke arbitrary Tcl scripts.

 *

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

 */

int

TkUnixDoOneXEvent(timePtr)

    Tcl_Time *timePtr;          /* Specifies the absolute time when the

                                 * call should time out. */

{

    TkDisplay *dispPtr;

    static fd_mask readMask[MASK_SIZE];

    struct timeval blockTime, *timeoutPtr;

    Tcl_Time now;

    int fd, index, bit, numFound, numFdBits = 0;

    /*

     * Look for queued events first.

     */

    if (Tcl_ServiceEvent(TCL_WINDOW_EVENTS)) {

        return 1;

    }

    /*

     * Compute the next block time and check to see if we have timed out.

     * Note that HP-UX defines tv_sec to be unsigned so we have to be

     * careful in our arithmetic.

     */

    if (timePtr) {

        TclpGetTime(&now);

        blockTime.tv_sec = timePtr->sec;

        blockTime.tv_usec = timePtr->usec - now.usec;

        if (blockTime.tv_usec < 0) {

            now.sec += 1;

            blockTime.tv_usec += 1000000;

        }

        if (blockTime.tv_sec < now.sec) {

            blockTime.tv_sec = 0;

            blockTime.tv_usec = 0;

        } else {

            blockTime.tv_sec -= now.sec;

        }

        timeoutPtr = &blockTime;

    } else {

        timeoutPtr = NULL;

    }

    /*

     * Set up the select mask for all of the displays.  If a display has

     * data pending, then we want to poll instead of blocking.

     */

    memset((VOID *) readMask, 0, MASK_SIZE*sizeof(fd_mask));

    for (dispPtr = tkDisplayList; dispPtr != NULL;

         dispPtr = dispPtr->nextPtr) {

        XFlush(dispPtr->display);

        if (XQLength(dispPtr->display) > 0) {

            blockTime.tv_sec = 0;

            blockTime.tv_usec = 0;

        }

        fd = ConnectionNumber(dispPtr->display);

        index = fd/(NBBY*sizeof(fd_mask));

        bit = 1 << (fd%(NBBY*sizeof(fd_mask)));

        readMask[index] |= bit;

        if (numFdBits <= fd) {

            numFdBits = fd+1;

        }

    }

    numFound = select(numFdBits, (SELECT_MASK *) &readMask[0], NULL, NULL,

            timeoutPtr);

    if (numFound <= 0) {

        /*

         * Some systems don't clear the masks after an error, so

         * we have to do it here.

         */

        memset((VOID *) readMask, 0, MASK_SIZE*sizeof(fd_mask));

    }

    /*

     * Process any new events on the display connections.

     */

    for (dispPtr = tkDisplayList; dispPtr != NULL;

         dispPtr = dispPtr->nextPtr) {

        fd = ConnectionNumber(dispPtr->display);

        index = fd/(NBBY*sizeof(fd_mask));

        bit = 1 << (fd%(NBBY*sizeof(fd_mask)));

        if ((readMask[index] & bit) || (XQLength(dispPtr->display) > 0)) {

            DisplayFileProc((ClientData)dispPtr, TCL_READABLE);

        }

    }

    if (Tcl_ServiceEvent(TCL_WINDOW_EVENTS)) {

        return 1;

    }

    /*

     * Check to see if we timed out.

     */

    if (timePtr) {

        TclpGetTime(&now);

        if ((now.sec > timePtr->sec) || ((now.sec == timePtr->sec)

                && (now.usec > timePtr->usec))) {

            return 0;

        }

    }

    /*

     * We had an event but we did not generate a Tcl event from it. Behave

     * as though we dealt with it. (JYL&SS)

     */

    return 1;

}

/*

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

 *

 * TkpSync --

 *

 *      This routine ensures that all pending X requests have been

 *      seen by the server, and that any pending X events have been

 *      moved onto the Tk event queue.

 *

 * Results:

 *      None.

 *

 * Side effects:

 *      Places new events on the Tk event queue.

 *

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

 */

void

TkpSync(display)

    Display *display;           /* Display to sync. */

{

    int numFound = 0;

    XEvent event;

    XSync(display, False);

    /*

     * Transfer events from the X event queue to the Tk event queue.

     */

    numFound = XQLength(display);

    while (numFound > 0) {

        XNextEvent(display, &event);

        Tk_QueueWindowEvent(&event, TCL_QUEUE_TAIL);

        numFound--;

    }

}