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/*

 * tclWinNotify.c --

 *

 *      This file contains Windows-specific procedures for the notifier,

 *      which is the lowest-level part of the Tcl event loop.  This file

 *      works together with ../generic/tclNotify.c.

 *

 * 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: tclWinNotify.c,v 1.1.1.1 2002-01-16 10:25:38 markom Exp $

 */

#include "tclInt.h"

#include "tclPort.h"

#include <winsock.h>

/*

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

 */

static int initialized = 0;

#define INTERVAL_TIMER 1                /* Handle of interval timer. */

/*

 * The following static structure contains the state information for the

 * Windows implementation of the Tcl notifier.

 */

static struct {

    HWND hwnd;                  /* Messaging window. */

    int timeout;                /* Current timeout value. */

    int timerActive;            /* 1 if interval timer is running. */

} notifier;

/*

 * Static routines defined in this file.

 */

static void             InitNotifier(void);

static void             NotifierExitHandler(ClientData clientData);

static LRESULT CALLBACK NotifierProc(HWND hwnd, UINT message,

                            WPARAM wParam, LPARAM lParam);

static void             UpdateTimer(int timeout);

/*

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

 *

 * InitNotifier --

 *

 *      Initializes the notifier window.

 *

 * Results:

 *      None.

 *

 * Side effects:

 *      Creates a new notifier window and window class.

 *

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

 */

static void

InitNotifier(void)

{

    WNDCLASS class;

    initialized = 1;

    notifier.timerActive = 0;

    class.style = 0;

    class.cbClsExtra = 0;

    class.cbWndExtra = 0;

    class.hInstance = TclWinGetTclInstance();

    class.hbrBackground = NULL;

    class.lpszMenuName = NULL;

    class.lpszClassName = "TclNotifier";

    class.lpfnWndProc = NotifierProc;

    class.hIcon = NULL;

    class.hCursor = NULL;

    if (!RegisterClass(&class)) {

        panic("Unable to register TclNotifier window class");

    }

    notifier.hwnd = CreateWindow("TclNotifier", "TclNotifier", WS_TILED,

            0, 0, 0, 0, NULL, NULL, TclWinGetTclInstance(), NULL);

    Tcl_CreateExitHandler(NotifierExitHandler, NULL);

}

/*

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

 *

 * NotifierExitHandler --

 *

 *      This function is called to cleanup the notifier state before

 *      Tcl is unloaded.

 *

 * Results:

 *      None.

 *

 * Side effects:

 *      Destroys the notifier window.

 *

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

 */

static void

NotifierExitHandler(

    ClientData clientData)      /* Old window proc */

{

    initialized = 0;

    if (notifier.hwnd) {

        KillTimer(notifier.hwnd, INTERVAL_TIMER);

        DestroyWindow(notifier.hwnd);

        UnregisterClass("TclNotifier", TclWinGetTclInstance());

        notifier.hwnd = NULL;

    }

}

/*

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

 *

 * UpdateTimer --

 *

 *      This function starts or stops the notifier interval timer.

 *

 * Results:

 *      None.

 *

 * Side effects:

 *      None.

 *

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

 */

void

UpdateTimer(

    int timeout)                /* ms timeout, 0 means cancel timer */

{

    notifier.timeout = timeout;

    if (timeout != 0) {

        notifier.timerActive = 1;

        SetTimer(notifier.hwnd, INTERVAL_TIMER,

                    (unsigned long) notifier.timeout, NULL);

    } else {

        notifier.timerActive = 0;

        KillTimer(notifier.hwnd, INTERVAL_TIMER);

    }

}

/*

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

 *

 * Tcl_SetTimer --

 *

 *      This procedure sets the current notifier timer value.  The

 *      notifier will ensure that Tcl_ServiceAll() is called after

 *      the specified interval, even if no events have occurred.

 *

 * Results:

 *      None.

 *

 * Side effects:

 *      Replaces any previous timer.

 *

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

 */

void

Tcl_SetTimer(

    Tcl_Time *timePtr)          /* Maximum block time, or NULL. */

{

    UINT timeout;

    if (!initialized) {

        InitNotifier();

    }

    if (!timePtr) {

        timeout = 0;

    } else {

        /*

         * Make sure we pass a non-zero value into the timeout argument.

         * Windows seems to get confused by zero length timers.

         */

        timeout = timePtr->sec * 1000 + timePtr->usec / 1000;

        if (timeout == 0) {

            timeout = 1;

        }

    }

    UpdateTimer(timeout);

}

/*

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

 *

 * NotifierProc --

 *

 *      This procedure is invoked by Windows to process the timer

 *      message whenever we are using an external dispatch loop.

 *

 * Results:

 *      A standard windows result.

 *

 * Side effects:

 *      Services any pending events.

 *

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

 */

static LRESULT CALLBACK

NotifierProc(

    HWND hwnd,

    UINT message,

    WPARAM wParam,

    LPARAM lParam)

{

    if (message != WM_TIMER) {

        return DefWindowProc(hwnd, message, wParam, lParam);

    }

    /*

     * Process all of the runnable events.

     */

    Tcl_ServiceAll();

    return 0;

}

/*

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

 *

 * Tcl_WaitForEvent --

 *

 *      This function is called by Tcl_DoOneEvent to wait for new

 *      events on the message queue.  If the block time is 0, then

 *      Tcl_WaitForEvent just polls the event queue without blocking.

 *

 * Results:

 *      Returns -1 if a WM_QUIT message is detected, returns 1 if

 *      a message was dispatched, otherwise returns 0.

 *

 * Side effects:

 *      Dispatches a message to a window procedure, which could do

 *      anything.

 *

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

 */

int

Tcl_WaitForEvent(

    Tcl_Time *timePtr)          /* Maximum block time, or NULL. */

{

    MSG msg;

    int timeout;

    if (!initialized) {

        InitNotifier();

    }

    /*

     * Only use the interval timer for non-zero timeouts.  This avoids

     * generating useless messages when we really just want to poll.

     */

    if (timePtr) {

        timeout = timePtr->sec * 1000 + timePtr->usec / 1000;

    } else {

        timeout = 0;

    }

    UpdateTimer(timeout);

    if (!timePtr || (timeout != 0)

            || PeekMessage(&msg, NULL, 0, 0, PM_NOREMOVE)) {

        if (!GetMessage(&msg, NULL, 0, 0)) {

            /*

             * The application is exiting, so repost the quit message

             * and start unwinding.

             */

            PostQuitMessage(msg.wParam);

            return -1;

        }

        /*

         * Handle timer expiration as a special case so we don't

         * claim to be doing work when we aren't.

         */

        if (msg.message == WM_TIMER && msg.hwnd == notifier.hwnd) {

            return 0;

        }

        TranslateMessage(&msg);

        DispatchMessage(&msg);

        return 1;

    }

    return 0;

}

/*

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

 *

 * Tcl_Sleep --

 *

 *      Delay execution for the specified number of milliseconds.

 *

 * Results:

 *      None.

 *

 * Side effects:

 *      Time passes.

 *

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

 */

void

Tcl_Sleep(ms)

    int ms;                     /* Number of milliseconds to sleep. */

{

    Sleep(ms);

}