/*
 * 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 1.17 2005/11/13 21:00:17 dkf Exp $
 */

#include "tkInt.h"
#include "tkUnixInt.h"
#include <signal.h>

/*
 * The following static indicates whether this module has been initialized
 * in the current thread.
 */

typedef struct ThreadSpecificData {
    int initialized;
} ThreadSpecificData;
static Tcl_ThreadDataKey dataKey;

#if defined(TK_USE_INPUT_METHODS) && defined(PEEK_XCLOSEIM)
/*
 * Structure used to peek into internal XIM data structure. This is only known
 * to work with XFree86.
 */

struct XIMPeek {
    void *junk1, *junk2;
    XIC ic_chain;
};
#endif

/*
 * Prototypes for functions that are referenced only in this file:
 */

static void		DisplayCheckProc(ClientData clientData, int flags);
static void		DisplayExitHandler(ClientData clientData);
static void		DisplayFileProc(ClientData clientData, int flags);
static void		DisplaySetupProc(ClientData clientData, int flags);
static void		TransferXEventsToTcl(Display *display);
#ifdef TK_USE_INPUT_METHODS
static void		OpenIM(TkDisplay *dispPtr);
#endif

/*
 *----------------------------------------------------------------------
 *
 * TkCreateXEventSource --
 *
 *	This function 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(void)
{
    ThreadSpecificData *tsdPtr = (ThreadSpecificData *)
            Tcl_GetThreadData(&dataKey, sizeof(ThreadSpecificData));

    if (!tsdPtr->initialized) {
	tsdPtr->initialized = 1;
	Tcl_CreateEventSource(DisplaySetupProc, DisplayCheckProc, NULL);
	TkCreateExitHandler(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)	/* Not used. */
{
    ThreadSpecificData *tsdPtr = (ThreadSpecificData *)
            Tcl_GetThreadData(&dataKey, sizeof(ThreadSpecificData));

    Tcl_DeleteEventSource(DisplaySetupProc, DisplayCheckProc, NULL);
    tsdPtr->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(
    CONST char *displayNameStr)
{
    TkDisplay *dispPtr;
    Display *display = XOpenDisplay(displayNameStr);

    if (display == NULL) {
	return NULL;
    }
    dispPtr = (TkDisplay *) ckalloc(sizeof(TkDisplay));
    memset(dispPtr, 0, sizeof(TkDisplay));
    dispPtr->display = display;
#ifdef TK_USE_INPUT_METHODS
    OpenIM(dispPtr);
#endif
    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 and unix-specific resources.
 *
 *----------------------------------------------------------------------
 */

void
TkpCloseDisplay(
    TkDisplay *dispPtr)
{
    TkSendCleanup(dispPtr);

    TkFreeXId(dispPtr);

    TkWmCleanup(dispPtr);

#ifdef TK_USE_INPUT_METHODS
#if TK_XIM_SPOT
    if (dispPtr->inputXfs) {
	XFreeFontSet(dispPtr->display, dispPtr->inputXfs);
    }
#endif
    if (dispPtr->inputMethod) {
	/*
	 * Calling XCloseIM with an input context that has not been freed can
	 * cause a crash. This crash has been reproduced under Linux systems
	 * with XFree86 3.3 and may have also been seen under Solaris 2.3.
	 * The crash is caused by a double free of memory inside the X
	 * library. Memory that was already deallocated may be accessed again
	 * inside XCloseIM. This bug can be avoided by making sure that a call
	 * to XDestroyIC is made for each XCreateIC call. This bug has been
	 * fixed in XFree86 4.2.99.2. The internal layout of the XIM structure
	 * changed in the XFree86 4.2 release so the test should not be run
	 * for with these new releases.
	 */

#if defined(TK_USE_INPUT_METHODS) && defined(PEEK_XCLOSEIM)
	int do_peek = 0;
	struct XIMPeek *peek;

	if (strstr(ServerVendor(dispPtr->display), "XFree86")) {
	    int vendrel = VendorRelease(dispPtr->display);
	    if (vendrel < 336) {
	        /* 3.3.4 and 3.3.5 */
	        do_peek = 1;
	    } else if (vendrel < 3900) {
	        /* Other 3.3.x versions */
	        do_peek = 1;
	    } else if (vendrel < 40000000) {
	        /* 4.0.x versions */
	        do_peek = 1;
	    } else {
	        /* Newer than 4.0 */
	        do_peek = 0;
	    }
	}

	if (do_peek) {
	    peek = (struct XIMPeek *) dispPtr->inputMethod;
	    if (peek->ic_chain != NULL) {
	        Tcl_Panic("input contexts not freed before XCloseIM");
	    }
	}
#endif
	XCloseIM(dispPtr->inputMethod);
    }
#endif

    if (dispPtr->display != 0) {
	Tcl_DeleteFileHandler(ConnectionNumber(dispPtr->display));
	(void) XSync(dispPtr->display, False);
	(void) XCloseDisplay(dispPtr->display);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * TkClipCleanup --
 *
 *	This function is called to cleanup resources associated with claiming
 *	clipboard ownership and for receiving selection get results. This
 *	function is called in tkWindow.c. This has to be called by the display
 *	cleanup function because we still need the access display elements.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Resources are freed - the clipboard may no longer be used.
 *
 *----------------------------------------------------------------------
 */

void
TkClipCleanup(
    TkDisplay *dispPtr)		/* Display associated with clipboard */
{
    if (dispPtr->clipWindow != NULL) {
	Tk_DeleteSelHandler(dispPtr->clipWindow, dispPtr->clipboardAtom,
		dispPtr->applicationAtom);
	Tk_DeleteSelHandler(dispPtr->clipWindow, dispPtr->clipboardAtom,
		dispPtr->windowAtom);

	Tk_DestroyWindow(dispPtr->clipWindow);
	Tcl_Release((ClientData) dispPtr->clipWindow);
	dispPtr->clipWindow = NULL;
    }
}

/*
 *----------------------------------------------------------------------
 *
 * DisplaySetupProc --
 *
 *	This function 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 clientData,	/* Not used. */
    int flags)
{
    TkDisplay *dispPtr;
    static Tcl_Time blockTime = { 0, 0 };

    if (!(flags & TCL_WINDOW_EVENTS)) {
	return;
    }

    for (dispPtr = TkGetDisplayList(); 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 (QLength(dispPtr->display) > 0) {
	    Tcl_SetMaxBlockTime(&blockTime);
	}
    }
}

/*
 *----------------------------------------------------------------------
 *
 *  TransferXEventsToTcl
 *
 *      Transfer events from the X event queue to the Tk event queue.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Moves queued X events onto the Tcl event queue.
 *
 *----------------------------------------------------------------------
 */

static void
TransferXEventsToTcl(
    Display *display)
{
    int numFound;
    XEvent event;

    numFound = QLength(display);

    /*
     * 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--;
    }
}

/*
 *----------------------------------------------------------------------
 *
 * DisplayCheckProc --
 *
 *	This function 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 clientData,	/* Not used. */
    int flags)
{
    TkDisplay *dispPtr;

    if (!(flags & TCL_WINDOW_EVENTS)) {
	return;
    }

    for (dispPtr = TkGetDisplayList(); dispPtr != NULL;
	    dispPtr = dispPtr->nextPtr) {
	XFlush(dispPtr->display);
	TransferXEventsToTcl(dispPtr->display);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * DisplayFileProc --
 *
 *	This function 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 clientData,	/* The display pointer. */
    int flags)			/* Should be TCL_READABLE. */
{
    TkDisplay *dispPtr = (TkDisplay *) clientData;
    Display *display = dispPtr->display;
    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);
    }

    TransferXEventsToTcl(display);
}

/*
 *----------------------------------------------------------------------
 *
 * 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(
    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) {
	Tcl_GetTime(&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 = TkGetDisplayList(); dispPtr != NULL;
	 dispPtr = dispPtr->nextPtr) {
	XFlush(dispPtr->display);
	if (QLength(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 = TkGetDisplayList(); 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) || (QLength(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) {
	Tcl_GetTime(&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 to sync. */
{
    XSync(display, False);

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

    TransferXEventsToTcl(display);
}
#ifdef TK_USE_INPUT_METHODS

/*
 *--------------------------------------------------------------
 *
 * OpenIM --
 *
 *	Tries to open an X input method, associated with the given display.
 *	Right now we can only deal with a bare-bones input style: no preedit,
 *	and no status.
 *
 * Results:
 *	Stores the input method in dispPtr->inputMethod; if there isn't a
 *	suitable input method, then NULL is stored in dispPtr->inputMethod.
 *
 * Side effects:
 *	An input method gets opened.
 *
 *--------------------------------------------------------------
 */

static void
OpenIM(
    TkDisplay *dispPtr)		/* Tk's structure for the display. */
{
    unsigned short i;
    XIMStyles *stylePtr;

    if (XSetLocaleModifiers("") == NULL) {
	goto error;
    }

    dispPtr->inputMethod = XOpenIM(dispPtr->display, NULL, NULL, NULL);
    if (dispPtr->inputMethod == NULL) {
	return;
    }

    if ((XGetIMValues(dispPtr->inputMethod, XNQueryInputStyle, &stylePtr,
	    NULL) != NULL) || (stylePtr == NULL)) {
	goto error;
    }

#if TK_XIM_SPOT
    /*
     * If we want to do over-the-spot XIM, we have to check that this mode is
     * supported. If not we will fall-through to the check below.
     */
    for (i = 0; i < stylePtr->count_styles; i++) {
	if (stylePtr->supported_styles[i]
		== (XIMPreeditPosition | XIMStatusNothing)) {
	    dispPtr->flags |= TK_DISPLAY_XIM_SPOT;
	    XFree(stylePtr);
	    return;
	}
    }
#endif /* TK_XIM_SPOT */

    for (i = 0; i < stylePtr->count_styles; i++) {
	if (stylePtr->supported_styles[i]
		== (XIMPreeditNothing | XIMStatusNothing)) {
	    XFree(stylePtr);
	    return;
	}
    }
    XFree(stylePtr);

  error:

    if (dispPtr->inputMethod) {
	/*
	 * This call should not suffer from any core dumping problems since we
	 * have not allocated any input contexts.
	 */

	XCloseIM(dispPtr->inputMethod);
	dispPtr->inputMethod = NULL;
    }
}
#endif /* TK_USE_INPUT_METHODS */

/*
 * Local Variables:
 * mode: c
 * c-basic-offset: 4
 * fill-column: 78
 * End:
 */