implement Topic; include "sys.m";	sys : Sys;	Qid, nulldir, OTRUNC: import sys;include "draw.m";include "styx.m";	styx : Styx;	Tmsg, Rmsg : import styx;include "styxservers.m";	styxservers : Styxservers;	Styxserver, Navigator, Fid : import styxservers;	nametree : Nametree;	Tree : import nametree; Topic : module{	init: fn(nil : ref Draw->Context, argv: list of string);}; Qroot, Qctl, Qmsgs, Qnewmsg, Qmsgdir : con big iota; uid : string; init (nil: ref Draw->Context, argv: list of string){	sys  = load Sys Sys->PATH;	styx = load Styx Styx->PATH;	styx->init();	styxservers = load Styxservers Styxservers->PATH;	styxservers->init(styx);	nametree = load Nametree Nametree->PATH;	nametree->init(); 	getuid();	(tree, treeop) := nametree->start();	tree.create(Qroot, dir(".", 8r777|Sys->DMDIR, Qroot));	tree.create(Qroot, dir("ctl", 8r666|sys->OTRUNC, Qctl));	tree.create(Qroot, dir("msgs", 8r666, Qmsgs));	tree.create(Qroot, dir("newmsg", 8r666, Qnewmsg)); 	nav := Navigator.new(treeop);	(tchan, srv) := Styxserver.new(sys->fildes(0), nav, Qroot);	spawn server(tchan, srv, tree);} getuid(){        buf := array [100] of byte;        fd := sys->open("/dev/user", Sys->OREAD);        uidlen := sys->read(fd, buf, len buf);        uid = string buf[0: uidlen];} dir(name: string, perm: int, qid: big): Sys->Dir{	d := sys->zerodir;	d.name = name;	d.uid = uid;	d.gid = uid;	d.qid.path = qid;	if (perm & Sys->DMDIR)		d.qid.qtype = Sys->QTDIR;	else		d.qid.qtype = Sys->QTFILE;		d.mode = perm;	return d;} server(tchan: chan of ref Tmsg, srv: ref Styxserver, tree: ref Tree){	readerId : int = 0; 	sys->pctl(Sys->NEWPGRP, nil); 	while((gm := <-tchan) != nil){		pick m := gm{		Wstat => # workaround for linux v9fs O_TRUNC issue			srv.reply(ref Rmsg.Wstat(m.tag));		Readerror =>			break;		Flush =>			srv.reply(ref Rmsg.Flush(m.tag));		Write =>			(c, err) := srv.canwrite(m);			if (c == nil){				srv.reply(ref Rmsg.Error(m.tag, err));			} else{				srv.reply(ref Rmsg.Write(m.tag, len m.data));			}		Read =>			(c, err) := srv.canread(m);			if (c == nil)				srv.reply(ref Rmsg.Error(m.tag, err)); 			case c.path{			Qmsgs =>				data := array of byte "TODO: list of messages here";				srv.reply(styxservers->readbytes(m, data));			Qnewmsg =>				data := array of byte string "from: \ndate: \n";				srv.reply(styxservers->readbytes(m, data));			* =>				srv.default(gm);			}		* => srv.default(gm);		}	}	tree.quit();} newmsgclient(fid: int, name: string){    #writemsgclients(fid, nil, "+++ " + name + " has arrived");    #msgclients = ref Msgclient(fid, name, keptmsg, nil, msgclients);}