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/*
 * Copyright (c) 2000 Greg Haerr <greg@censoft.com>
 * Copyright (c) 1991 David I. Bell
 * Permission is granted to use, distribute, or modify this source,
 * provided that this copyright notice remains intact.
 *
 * Graphics server event routines for windows.
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "serv.h"
 
/* readable error strings*/
char *nxErrorStrings[] = {
	GR_ERROR_STRINGS
};
 
#if NONETWORK
/* [copied from client.c]
 * The following is the user defined function for handling errors.
 * If this is not set, then the default action is to close the connection
 * to the server, describe the error, and then exit.  This error function
 * will only be called when the client asks for events.
 */
static GR_FNCALLBACKEVENT ErrorFunc = GrDefaultErrorHandler;
 
/* 
 * The default error handler which is called when the server
 * reports an error event and the client hasn't set a handler for error events.
 */
void 
GrDefaultErrorHandler(GR_EVENT *ep)
{
	if (ep->type == GR_EVENT_TYPE_ERROR) {
		EPRINTF("nxclient: Error (%s) ", ep->error.name);
		EPRINTF(nxErrorStrings[ep->error.code], ep->error.id);
		GrClose();
		exit(1);
	}
}
 
/*
 * Set an error handling routine, which will be called on any errors from
 * the server (when events are asked for by the client).  If zero is given,
 * then errors will be returned as regular events.  
 * Returns the previous error handler.
 */
GR_FNCALLBACKEVENT
GrSetErrorHandler(GR_FNCALLBACKEVENT fncb)
{
	GR_FNCALLBACKEVENT orig = ErrorFunc;
 
	ErrorFunc = fncb;
	return orig;
}
#endif /* NONETWORK*/
 
/*
 * Generate an error from a graphics function.
 * This creates a special event which describes the error.
 * Only one error event at a time can be saved for delivery to a client.
 * This is ok since there are usually lots of redundant errors generated
 * before the client can notice, errors occurs after the fact, and clients
 * can't do much about them except complain and die.  The error is saved
 * specially so that memory problems cannot occur.
 */
void GsError(GR_ERROR code, GR_ID id)
{
	GR_EVENT_ERROR	*ep;		/* event to describe error */
 
	EPRINTF("nano-X: GsError ");
	if(curfunc)
		EPRINTF("(%s) ", curfunc);
	EPRINTF(nxErrorStrings[code], id);
 
	/* if no clients, nothing to report*/
	if (!curclient)
		return;
 
	/* queue the error event regardless of GrSelectEvents*/
	ep = (GR_EVENT_ERROR *)GsAllocEvent(curclient);
	ep->type = GR_EVENT_TYPE_ERROR;
	ep->name[0] = 0;
	if(curfunc) {
		strncpy(ep->name, curfunc, sizeof(GR_FUNC_NAME));
		ep->name[sizeof(GR_FUNC_NAME)-1] = '\0';
	}
	ep->code = code;
	ep->id = id;
}
 
/*
 * Allocate an event to be passed back to the specified client.
 * The event is already chained onto the event queue, and only
 * needs filling out.  Returns NULL with an error generated if
 * the event cannot be allocated.
 */
GR_EVENT *GsAllocEvent(GR_CLIENT *client)
{
	GR_EVENT_LIST	*elp;		/* current element list */
	GR_CLIENT	*oldcurclient;	/* old current client */
 
	/*
	 * Get a new event structure from the free list, or else
	 * allocate it using malloc.
	 */
	elp = eventfree;
	if (elp)
		eventfree = elp->next;
	else {
		elp = (GR_EVENT_LIST *) malloc(sizeof(GR_EVENT_LIST));
		if (elp == NULL) {
			oldcurclient = curclient;
			curclient = client;
			GsError(GR_ERROR_MALLOC_FAILED, 0);
			curclient = oldcurclient;
			return NULL;
		}
	}
 
	/*
	 * Add the event to the end of the event list.
	 */
	if (client->eventhead)
		client->eventtail->next = elp;
	else
		client->eventhead = elp;
	client->eventtail = elp;
	elp->next = NULL;
	elp->event.type = GR_EVENT_TYPE_NONE;
 
	return &elp->event;
}
 
/*
 * Update mouse status and issue events on it if necessary.
 * This function doesn't block, but is normally only called when
 * there is known to be some data waiting to be read from the mouse.
 */
GR_BOOL GsCheckMouseEvent(void)
{
	GR_COORD	rootx;		/* latest mouse x position */
	GR_COORD	rooty;		/* latest mouse y position */
	int		newbuttons;	/* latest buttons */
	int		mousestatus;	/* latest mouse status */
 
	/* Read the latest mouse status: */
	mousestatus = GdReadMouse(&rootx, &rooty, &newbuttons);
	if(mousestatus < 0) {
		GsError(GR_ERROR_MOUSE_ERROR, 0);
		return FALSE;
	} else if(mousestatus) {	/* Deliver events as appropriate: */	
		GsHandleMouseStatus(rootx, rooty, newbuttons);
 
		/* possibly reset portrait mode based on mouse position*/
		if (autoportrait)
			GsSetPortraitModeFromXY(rootx, rooty);
		return TRUE;
	}
	return FALSE;
}
 
/*
 * Update keyboard status and issue events on it if necessary.
 * This function doesn't block, but is normally only called when
 * there is known to be some data waiting to be read from the keyboard.
 */
GR_BOOL GsCheckKeyboardEvent(void)
{
	MWKEY	 	mwkey;		/* latest character */
	MWKEYMOD 	modifiers;	/* latest modifiers */
	MWSCANCODE	scancode;
	int	 	keystatus;	/* latest keyboard status */
 
	/* Read the latest keyboard status: */
	keystatus = GdReadKeyboard(&mwkey, &modifiers, &scancode);
 
	if(keystatus < 0) {
		if(keystatus == -2)	/* special case return code*/
			GsTerminate();
		GsError(GR_ERROR_KEYBOARD_ERROR, 0);
		return FALSE;
	} else if(keystatus) {		/* Deliver events as appropriate: */	
		switch (mwkey) {
		case MWKEY_QUIT:
			GsTerminate();
			/* no return*/
		case MWKEY_REDRAW:
			GsRedrawScreen();
			break;
		case MWKEY_PRINT:
			if (keystatus == 1)
				GdCaptureScreen("screen.bmp");
			break;
		}
		GsDeliverKeyboardEvent(0,
			(keystatus==1?
			GR_EVENT_TYPE_KEY_DOWN: GR_EVENT_TYPE_KEY_UP),
			mwkey, modifiers, scancode);
		return TRUE;
	}
	return FALSE;
}
 
/*
 * Handle all mouse events.  These are mouse enter, mouse exit, mouse
 * motion, mouse position, button down, and button up.  This also moves
 * the cursor to the new mouse position and changes it shape if needed.
 */
void GsHandleMouseStatus(GR_COORD newx, GR_COORD newy, int newbuttons)
{
	int	 changebuttons;	/* buttons that have changed */
	MWKEYMOD modifiers;	/* latest modifiers */
 
	GdGetModifierInfo(NULL, &modifiers); /* Read kbd modifiers */
 
	/*
	 * First, if the mouse has moved, then position the cursor to the
	 * new location, which will send mouse enter, mouse exit, focus in,
	 * and focus out events if needed.  Check here for mouse motion and
	 * mouse position events.  Flush the device queue to make sure the
	 * new cursor location is quickly seen by the user.
	 */
	if ((newx != cursorx) || (newy != cursory)) {
		GsResetScreenSaver();
		GrMoveCursor(newx, newy);
		GsDeliverMotionEvent(GR_EVENT_TYPE_MOUSE_MOTION,
			newbuttons, modifiers);
		GsDeliverMotionEvent(GR_EVENT_TYPE_MOUSE_POSITION,
			newbuttons, modifiers);
	}
 
	/*
	 * Next, generate a button up event if any buttons have been released.
	 */
	changebuttons = (curbuttons & ~newbuttons);
	if (changebuttons) {
		GsResetScreenSaver();
		GsDeliverButtonEvent(GR_EVENT_TYPE_BUTTON_UP,
			newbuttons, changebuttons, modifiers);
	}
 
	/*
	 * Finally, generate a button down event if any buttons have been
	 * pressed.
	 */
	changebuttons = (~curbuttons & newbuttons);
	if (changebuttons) {
		GsResetScreenSaver();
		GsDeliverButtonEvent(GR_EVENT_TYPE_BUTTON_DOWN,
			newbuttons, changebuttons, modifiers);
	}
 
	curbuttons = newbuttons;
}
 
/*
 * Deliver a mouse button event to the clients which have selected for it.
 * Each client can only be delivered one instance of the event.  The window
 * the event is delivered for is either the smallest one containing the
 * mouse coordinates, or else one of its direct ancestors.  The lowest
 * window in that tree which has enabled for the event gets it.  This scan
 * is done independently for each client.  If a window with the correct
 * noprop mask is reached, or if no window selects for the event, then the
 * event is discarded for that client.  Special case: for the first client
 * that is enabled for both button down and button up events in a window,
 * then the pointer is implicitly grabbed by that window when a button is
 * pressed down in that window.  The grabbing remains until all buttons are
 * released.  While the pointer is grabbed, no other clients or windows can
 * receive button down or up events.
 */
void GsDeliverButtonEvent(GR_EVENT_TYPE type, int buttons, int changebuttons,
			int modifiers)
{
	GR_EVENT_BUTTON	*ep;		/* mouse button event */
	GR_WINDOW	*wp;		/* current window */
	GR_EVENT_CLIENT	*ecp;		/* current event client */
	GR_CLIENT	*client;	/* current client */
	GR_WINDOW_ID	subwid;		/* subwindow id event is for */
	GR_EVENT_MASK	eventmask;	/* event mask */
	GR_EVENT_MASK	tempmask;	/* to get around compiler bug */
 
	eventmask = GR_EVENTMASK(type);
	if (eventmask == 0)
		return;
 
	/*
	 * If the pointer is implicitly grabbed, then the only window
	 * which can receive button events is that window.  Otherwise
	 * the window the pointer is in gets the events.  Determine the
	 * subwindow by seeing if it is a child of the grabbed button.
	 */
	wp = mousewp;
	subwid = wp->id;
 
	if (grabbuttonwp) {
		while ((wp != rootwp) && (wp != grabbuttonwp))
			wp = wp->parent;
#if 0
		if (wp != grabbuttonwp)
			subwid = grabbuttonwp->id;
#endif
		wp = grabbuttonwp;
	}
 
	for (;;) {
		for (ecp = wp->eventclients; ecp; ecp = ecp->next) {
			if ((ecp->eventmask & eventmask) == 0)
				continue;
 
			client = ecp->client;
 
			/*
			 * If this is a button down, the buttons are not
			 * yet grabbed, and this client is enabled for both
			 * button down and button up events, then implicitly
			 * grab the window for him.
			 */
			if ((type == GR_EVENT_TYPE_BUTTON_DOWN)
				&& (grabbuttonwp == NULL))
			{
				tempmask = GR_EVENT_MASK_BUTTON_UP;
				if (ecp->eventmask & tempmask) {
/*DPRINTF("nano-X: implicit grab on window %d\n", wp->id);*/
					grabbuttonwp = wp;
				}
			}
 
			ep = (GR_EVENT_BUTTON *) GsAllocEvent(client);
			if (ep == NULL)
				continue;
 
			ep->type = type;
			ep->wid = wp->id;
			ep->subwid = subwid;
			ep->rootx = cursorx;
			ep->rooty = cursory;
			ep->x = cursorx - wp->x;
			ep->y = cursory - wp->y;
			ep->buttons = buttons;
			ep->changebuttons = changebuttons;
			ep->modifiers = modifiers;
			ep->time = GsGetTickCount();
		}
 
		/*
		 * Events do not propagate if the window was grabbed.
		 * Also release the grab if the buttons are now all released,
		 * which can cause various events.
		 */
		if (grabbuttonwp) {
			if (buttons == 0) {
				grabbuttonwp = NULL;
				GrMoveCursor(cursorx, cursory);
			}
			return;
		}
 
		if ((wp == rootwp) || (wp->nopropmask & eventmask))
			return;
 
		wp = wp->parent;
	}
}
 
/*
 * Deliver a mouse motion event to the clients which have selected for it.
 * Each client can only be delivered one instance of the event.  The window
 * the event is delivered for is either the smallest one containing the
 * mouse coordinates, or else one of its direct ancestors.  The lowest
 * window in that tree which has enabled for the event gets it.  This scan
 * is done independently for each client.  If a window with the correct
 * noprop mask is reached, or if no window selects for the event, then the
 * event is discarded for that client.  Special case: If the event type is
 * GR_EVENT_TYPE_MOUSE_POSITION, then only the last such event is queued for
 * any single client to reduce events.  If the mouse is implicitly grabbed,
 * then only the grabbing window receives the events, and continues to do
 * so even if the mouse is currently outside of the grabbing window.
 */
void GsDeliverMotionEvent(GR_EVENT_TYPE type, int buttons, MWKEYMOD modifiers)
{
	GR_EVENT_MOUSE	*ep;		/* mouse motion event */
	GR_WINDOW	*wp;		/* current window */
	GR_EVENT_CLIENT	*ecp;		/* current event client */
	GR_CLIENT	*client;	/* current client */
	GR_WINDOW_ID	subwid;		/* subwindow id event is for */
	GR_EVENT_MASK	eventmask;	/* event mask */
 
	eventmask = GR_EVENTMASK(type);
	if (eventmask == 0)
		return;
 
	wp = mousewp;
	subwid = wp->id;
 
	if (grabbuttonwp) {
		while ((wp != rootwp) && (wp != grabbuttonwp))
			wp = wp->parent;
#if 0
		if (wp != grabbuttonwp)
			subwid = grabbuttonwp->id;
#endif
		wp = grabbuttonwp;
	}
 
	for (;;) {
		for (ecp = wp->eventclients; ecp; ecp = ecp->next) {
			if ((ecp->eventmask & eventmask) == 0)
				continue;
 
			client = ecp->client;
 
			/*
			 * If the event is for just the latest position,
			 * then search the event queue for an existing
			 * event of this type (if any), and free it.
			 */
			if (type == GR_EVENT_TYPE_MOUSE_POSITION) 
				GsFreePositionEvent(client, wp->id, subwid);
 
			ep = (GR_EVENT_MOUSE *) GsAllocEvent(client);
			if (ep == NULL)
				continue;
 
			ep->type = type;
			ep->wid = wp->id;
			ep->subwid = subwid;
			ep->rootx = cursorx;
			ep->rooty = cursory;
			ep->x = cursorx - wp->x;
			ep->y = cursory - wp->y;
			ep->buttons = buttons;
			ep->modifiers = modifiers;
		}
 
		if ((wp == rootwp) || grabbuttonwp ||
			(wp->nopropmask & eventmask))
				return;
 
		wp = wp->parent;
	}
}
 
/*
 * Deliver a keyboard event to one of the clients which have selected for it.
 * Only the first client found gets the event (no duplicates are sent).  The
 * window the event is delivered to is either the smallest one containing
 * the mouse coordinates, or else one of its direct ancestors (if such a
 * window is a descendant of the focus window), or else just the focus window.
 * The lowest window in that tree which has enabled for the event gets it.
 * If a window with the correct noprop mask is reached, or if no window selects
 * for the event, then the event is discarded.
 */
void GsDeliverKeyboardEvent(GR_WINDOW_ID wid, GR_EVENT_TYPE type,
	GR_KEY keyvalue, GR_KEYMOD modifiers, GR_SCANCODE scancode)
{
	GR_EVENT_KEYSTROKE	*ep;		/* keystroke event */
	GR_WINDOW		*wp;		/* current window */
	GR_WINDOW		*tempwp;	/* temporary window pointer */
	GR_EVENT_CLIENT		*ecp;		/* current event client */
	GR_WINDOW_ID		subwid;		/* subwindow id event is for */
	GR_EVENT_MASK		eventmask;	/* event mask */
	GR_WINDOW		*kwp;
 
	eventmask = GR_EVENTMASK(type);
	if (eventmask == 0)
		return;
 
	GsResetScreenSaver();
 
	/* if window id passed, use it, otherwise focus window*/
	if (wid) {
		kwp = GsFindWindow(wid);
		if (!kwp)
			return;
	} else
		kwp = focuswp;
	wp = mousewp;
	subwid = wp->id;
 
	/*
	 * See if the actual window the pointer is in is a descendant of
	 * the focus window.  If not, then ignore it, and force the input
	 * into the focus window itself.
	 */
	tempwp = wp;
	while ((tempwp != kwp) && (tempwp != rootwp))
		tempwp = tempwp->parent;
 
	if (tempwp != kwp) {
		wp = kwp;
		subwid = wp->id;
	}
 
	/*
	 * Now walk upwards looking for the first window which will accept
	 * the keyboard event.  However, do not go beyond the focus window,
	 * and only give the event to one client.
	 */
	for (;;) {
		for (ecp = wp->eventclients; ecp; ecp = ecp->next) {
			if ((ecp->eventmask & eventmask) == 0)
				continue;
 
			ep = (GR_EVENT_KEYSTROKE *) GsAllocEvent(ecp->client);
			if (ep == NULL)
				return;
 
			ep->type = type;
			ep->wid = wp->id;
			ep->subwid = subwid;
			ep->rootx = cursorx;
			ep->rooty = cursory;
			ep->x = cursorx - wp->x;
			ep->y = cursory - wp->y;
			ep->buttons = curbuttons;
			ep->modifiers = modifiers;
			ep->ch = keyvalue;
			ep->scancode = scancode;
			return;			/* only one client gets it */
		}
 
		if ((wp == rootwp) || (wp == kwp) ||
			(wp->nopropmask & eventmask))
				return;
 
		wp = wp->parent;
	}
}
 
/*
 * Try to deliver a exposure event to the clients which have selected for it.
 * This does not send exposure events for unmapped or input-only windows.
 * Exposure events do not propagate upwards.
 */
void
GsDeliverExposureEvent(GR_WINDOW *wp, GR_COORD x, GR_COORD y,
	GR_SIZE width, GR_SIZE height)
{
	GR_EVENT_EXPOSURE	*ep;		/* exposure event */
	GR_EVENT_CLIENT		*ecp;		/* current event client */
 
	if (wp->unmapcount || !wp->output)
		return;
 
	for (ecp = wp->eventclients; ecp; ecp = ecp->next) {
		if ((ecp->eventmask & GR_EVENT_MASK_EXPOSURE) == 0)
			continue;
 
		GsFreeExposureEvent(ecp->client, wp->id, x, y, width, height);
 
		ep = (GR_EVENT_EXPOSURE *) GsAllocEvent(ecp->client);
		if (ep == NULL)
			continue;
 
		ep->type = GR_EVENT_TYPE_EXPOSURE;
		ep->wid = wp->id;
		ep->x = x;
		ep->y = y;
		ep->width = width;
		ep->height = height;
	}
}
 
/*
 * Search for an enclosed expose event in the specified client's
 * event queue, and remove it.  This is used to prevent multiple expose
 * events from being delivered, thus providing a more pleasing visual
 * redraw effect than if the events were all sent.
 */
void
GsFreeExposureEvent(GR_CLIENT *client, GR_WINDOW_ID wid, GR_COORD x,
	GR_COORD y, GR_SIZE width, GR_SIZE height)
{
	GR_EVENT_LIST	*elp;		/* current element list */
	GR_EVENT_LIST	*prevelp;	/* previous element list */
 
	prevelp = NULL;
	for (elp = client->eventhead; elp; prevelp = elp, elp = elp->next) {
		if (elp->event.type != GR_EVENT_TYPE_EXPOSURE ||
		    elp->event.exposure.wid != wid)
			continue;
		if (elp->event.exposure.x < x || elp->event.exposure.y < y ||
		    elp->event.exposure.x+elp->event.exposure.width > x+width ||
		    elp->event.exposure.y+elp->event.exposure.height > y+height)
			continue;
 
		/*
		 * Found one, remove it and put it back on the free list.
		 */
		if (prevelp)
			prevelp->next = elp->next;
		else
			client->eventhead = elp->next;
		if (client->eventtail == elp)
			client->eventtail = prevelp;
 
		elp->next = eventfree;
		eventfree = elp;
		return;
	}
}
 
/*
 * Try to deliver an update event to the clients which have selected for it.
 */
void GsDeliverUpdateEvent(GR_WINDOW *wp, GR_UPDATE_TYPE utype, GR_COORD x,
			GR_COORD y, GR_SIZE width, GR_SIZE height)
{
	GR_EVENT_MASK		cmask = GR_EVENT_MASK_UPDATE;
	GR_EVENT_UPDATE		*ep;		/* update event */
	GR_EVENT_CLIENT		*ecp;		/* current event client */
	GR_WINDOW_ID		id = wp->id;
	int			lcount = 0;
 
	/* adjust reported x,y to be parent-relative*/
	if (wp->parent) {
		x -= wp->parent->x;
		y -= wp->parent->y;
	}
 
update_again:
	for (ecp = wp->eventclients; ecp; ecp = ecp->next) {
		if ((ecp->eventmask & cmask) == 0)
			continue;
 
		ep = (GR_EVENT_UPDATE *) GsAllocEvent(ecp->client);
		if (ep == NULL)
			continue;
 
		ep->type = lcount? 
			GR_EVENT_TYPE_CHLD_UPDATE: GR_EVENT_TYPE_UPDATE;
		ep->utype = utype;
		ep->wid = wp->id;	/* GrSelectEvents window id*/
		ep->subwid = id;	/* update window id*/
		ep->x = x;
		ep->y = y;
		ep->width = width;
		ep->height = height;
	}
 
	/* If we are currently checking the window updated, go back and 
	 * check its parent too */
	if (!lcount++) {	
		wp = wp->parent;
		/* check for NULL on root window id*/
		if (wp == NULL)
			return;
		cmask = GR_EVENT_MASK_CHLD_UPDATE;
		goto update_again;
	}
}
 
/*
 * Try to deliver a general event such as focus in, focus out, mouse enter,
 * or mouse exit to the clients which have selected for it.  These events
 * only have the window id as data, and do not propagate upwards.
 */
void GsDeliverGeneralEvent(GR_WINDOW *wp, GR_EVENT_TYPE type, GR_WINDOW *other)
{
	GR_EVENT_GENERAL	*gp;		/* general event */
	GR_EVENT_CLIENT		*ecp;		/* current event client */
	GR_EVENT_MASK		eventmask;	/* event mask */
 
	eventmask = GR_EVENTMASK(type);
	if (eventmask == 0)
		return;
 
	for (ecp = wp->eventclients; ecp; ecp = ecp->next) {
		if ((ecp->eventmask & eventmask) == 0)
			continue;
 
		gp = (GR_EVENT_GENERAL *) GsAllocEvent(ecp->client);
		if (gp == NULL)
			continue;
 
		gp->type = type;
		gp->wid = wp->id;
		if (other)
			gp->otherid = other->id;
		else gp->otherid = 0;
	}
}
 
/*
 * Deliver a portrait mode changed event to all windows which
 * have selected for it.
 */
void GsDeliverPortraitChangedEvent(void)
{
	GR_WINDOW		*wp;
	GR_EVENT_GENERAL	*gp;
	GR_EVENT_CLIENT		*ecp;
 
	for (wp=listwp; wp; wp=wp->next) {
		for (ecp = wp->eventclients; ecp; ecp = ecp->next) {
			if ((ecp->eventmask & GR_EVENT_MASK_PORTRAIT_CHANGED) == 0)
				continue;
 
			gp = (GR_EVENT_GENERAL *) GsAllocEvent(ecp->client);
			if (gp == NULL)
				continue;
 
			gp->type = GR_EVENT_TYPE_PORTRAIT_CHANGED;
			gp->wid = wp->id;
			gp->otherid = 0;
		}
	}
}
 
/*
 * Deliver a Screen Saver event. There is only one parameter- activate the
 * screen saver or deactivate it. We only deliver it to the root window,
 * but we do send it to every client which has selected for it (because the
 * program which starts the screen saver on an activate event might not also
 * be the screen saver program which wants to catch the deactivate event).
 */
void GsDeliverScreenSaverEvent(GR_BOOL activate)
{
	GR_EVENT_SCREENSAVER	*gp;		/* screensaver event */
	GR_EVENT_CLIENT		*ecp;		/* current event client */
 
	for (ecp = rootwp->eventclients; ecp; ecp = ecp->next) {
		if ((ecp->eventmask & GR_EVENT_MASK_SCREENSAVER) == 0)
			continue;
 
		gp = (GR_EVENT_SCREENSAVER *) GsAllocEvent(ecp->client);
		if (gp == NULL)
			continue;
 
		gp->type = GR_EVENT_TYPE_SCREENSAVER;
		gp->activate = activate;
	}
}
 
/*
 * Deliver a client data request event. Delivered to the clients who have
 * selected for this event on the specified window only.
 */
void
GsDeliverClientDataReqEvent(GR_WINDOW_ID wid, GR_WINDOW_ID rid,
			GR_SERIALNO serial, GR_MIMETYPE mimetype)
{
	GR_EVENT_CLIENT_DATA_REQ *gp;		/* client data request event */
	GR_EVENT_CLIENT		*ecp;		/* current event client */
	GR_WINDOW *wp;
 
	if(!(wp = GsFindWindow(wid))) return;
 
	for (ecp = wp->eventclients; ecp; ecp = ecp->next) {
		if ((ecp->eventmask & GR_EVENT_MASK_CLIENT_DATA_REQ) == 0)
			continue;
 
		gp = (GR_EVENT_CLIENT_DATA_REQ *) GsAllocEvent(ecp->client);
		if (gp == NULL)
			continue;
 
		gp->type = GR_EVENT_TYPE_CLIENT_DATA_REQ;
		gp->wid = wid;
		gp->rid = rid;
		gp->serial = serial;
		gp->mimetype = mimetype;
		continue;
	}
}
 
/*
 * Deliver a client data event. Delivered to the clients who have selected for
 * this event on the specified window only.
 */
void
GsDeliverClientDataEvent(GR_WINDOW_ID wid, GR_WINDOW_ID rid,
	GR_SERIALNO serial, GR_LENGTH len, GR_LENGTH thislen, void *data)
{
	GR_EVENT_CLIENT_DATA *gp;		/* client data request event */
	GR_EVENT_CLIENT		*ecp;		/* current event client */
	GR_WINDOW *wp;
 
	if(!(wp = GsFindWindow(wid))) return;
 
	for (ecp = wp->eventclients; ecp; ecp = ecp->next) {
		if ((ecp->eventmask & GR_EVENT_MASK_CLIENT_DATA) == 0)
			continue;
 
		gp = (GR_EVENT_CLIENT_DATA *) GsAllocEvent(ecp->client);
		if (gp == NULL)
			continue;
 
		gp->type = GR_EVENT_TYPE_CLIENT_DATA;
		gp->wid = wid;
		gp->rid = rid;
		gp->serial = serial;
		gp->len = len;
		gp->datalen = thislen;
		if(!(gp->data = malloc(thislen))) {
			GsError(GR_ERROR_MALLOC_FAILED, wid);
			return;
		}
		memcpy(gp->data, data, thislen);
		continue;
	}
}
 
/*
 * Search for a matching mouse position event in the specified client's
 * event queue, and remove it.  This is used to prevent multiple position
 * events from being delivered, thus providing a more efficient rubber-
 * banding effect than if the mouse motion events were all sent.
 */
void
GsFreePositionEvent(GR_CLIENT *client, GR_WINDOW_ID wid, GR_WINDOW_ID subwid)
{
	GR_EVENT_LIST	*elp;		/* current element list */
	GR_EVENT_LIST	*prevelp;	/* previous element list */
 
	prevelp = NULL;
	for (elp = client->eventhead; elp; prevelp = elp, elp = elp->next) {
		if (elp->event.type != GR_EVENT_TYPE_MOUSE_POSITION)
			continue;
		if (elp->event.mouse.wid != wid)
			continue;
		if (elp->event.mouse.subwid != subwid)
			continue;
 
		/*
		 * Found one, remove it and put it back on the free list.
		 */
		if (prevelp)
			prevelp->next = elp->next;
		else
			client->eventhead = elp->next;
		if (client->eventtail == elp)
			client->eventtail = prevelp;
 
		elp->next = eventfree;
		eventfree = elp;
		return;
	}
}
 
/*
 * Deliver a "selection owner changed" event to all windows which have
 * selected for it. We deliver this event to all clients which have selected
 * to receive GR_EVENT_TYPE_SELECTION_CHANGED events for the window of the
 * _previous_ selection owner.
 */
void GsDeliverSelectionChangedEvent(GR_WINDOW_ID old_owner,
					GR_WINDOW_ID new_owner)
{
	GR_EVENT_SELECTION_CHANGED *gp;		/* selection changed event */
	GR_EVENT_CLIENT		*ecp;		/* current event client */
	GR_WINDOW *wp;
 
	if(!(wp = GsFindWindow(old_owner))) return;
 
	for (ecp = wp->eventclients; ecp; ecp = ecp->next) {
		if ((ecp->eventmask & GR_EVENT_MASK_SELECTION_CHANGED) == 0)
			continue;
 
		fprintf(stderr, "Delivering a selection changed event\n");
		gp = (GR_EVENT_SELECTION_CHANGED *) GsAllocEvent(ecp->client);
		if (gp == NULL)
			continue;
 
		gp->type = GR_EVENT_TYPE_SELECTION_CHANGED;
		gp->new_owner = new_owner;
	}
}
 
void GsDeliverTimerEvent (GR_CLIENT *client, GR_WINDOW_ID wid, GR_TIMER_ID tid)
{
    GR_EVENT_TIMER    *event;           /* general event */
    GR_EVENT_CLIENT   *ecp;             /* current event client */
    GR_WINDOW         *wp;              /* current window */
 
    if ((wp = GsFindWindow (wid)) == NULL)
    {
        return;
    }
 
    for (ecp = wp->eventclients; ecp != NULL; ecp = ecp->next) 
    {
        if ((ecp->client == client) && ((ecp->eventmask & GR_EVENT_MASK_TIMER) != 0))
        {
            event = (GR_EVENT_TIMER*) GsAllocEvent (client);
            if (event == NULL)
            {
                break;
            }
 
            event->type = GR_EVENT_TYPE_TIMER;
            event->wid  = wid;
            event->tid  = tid;
        }
    }
}