implement Wdiff; include "sys.m";	sys: Sys;include "draw.m";include "bufio.m";	bufio: Bufio;	Iobuf: import bufio;include "arg.m";	arg: Arg;include "wrap.m";	wrap : Wrap;include "sh.m";include "keyring.m";	keyring : Keyring;  Wdiff: module{	init:	fn(nil: ref Draw->Context, nil: list of string);}; root := "/";bflag : int;listing : int;package: int; diff(w : ref Wrap->Wrapped, name : string, c : chan of int){	sys->pctl(Sys->FORKFD, nil);	wrapped := w.root+"/"+name;	local := root+"/"+name;	(ok, dir) := sys->stat(local);	if (ok < 0) {		sys->print("cannot stat %s\n", local);		c <-= -1;		return;	}	(ok, dir) = sys->stat(wrapped);	if (ok < 0) {		sys->print("cannot stat %s\n", wrapped);		c <-= -1;		return;	}	cmd := "/dis/diff.dis";	m := load Command cmd;	if(m == nil) {		c <-= -1;		return;	}	if (bflag)		m->init(nil, cmd :: "-b" :: wrapped :: local :: nil);	else		m->init(nil, cmd :: wrapped :: local :: nil);	c <-= 0;}	fatal(err : string){	sys->fprint(sys->fildes(2), "%s\n", err);	exit;} init(nil: ref Draw->Context, args: list of string){	sys = load Sys Sys->PATH;	bufio = load Bufio Bufio->PATH;	arg = load Arg Arg->PATH;	keyring = load Keyring Keyring->PATH;	wrap = load Wrap Wrap->PATH;	wrap->init(bufio); 	arg->init(args);	while ((c := arg->opt()) != 0) {		case c {			'b' =>				bflag = 1;			'l' =>				listing = 1;			'p' =>				package = 1;			'r' =>				root = arg->arg();				if (root == nil)					fatal("missing root name");			* =>				fatal(sys->sprint("bad argument -%c", c));		}	}	args = arg->argv();	if (args == nil || tl args != nil)		fatal("usage: install/wdiff [-blp] [-r root] package");	(ok, dir) := sys->stat(hd args);	if (ok < 0)		fatal(sys->sprint("no such file %s", hd args));	w := wrap->openwraphdr(hd args, root, nil, !listing);	if (w == nil)		fatal("no such package found"); 	if(package){		while(w.nu > 0 && w.u[w.nu-1].typ == wrap->UPD)			w.nu--;	} 	digest := array[keyring->MD5dlen] of { * => byte 0 };	digest0 := array[keyring->MD5dlen] of { * => byte 0 }; 	# loop through each md5sum file of each package in increasing time order	for(i := 0; i < w.nu; i++){		b := bufio->open(w.u[i].dir+"/md5sum", Sys->OREAD);		if (b == nil)			fatal("md5sum file not found");		while ((p := b.gets('\n')) != nil) {			(n, lst) := sys->tokenize(p, " \t\n");			if (n != 2)				fatal("error in md5sum file");			p = hd lst;			q := root+"/"+p;			(ok, dir) = sys->stat(q);			if (ok >= 0 && (dir.mode & Sys->DMDIR))				continue;			t: int;			(ok, t) = wrap->getfileinfo(w, p, nil, digest0, nil);			if(ok < 0){				sys->print("cannot happen\n");				continue;			}			if(t != w.u[i].time)	# covered by later update				continue;			if (wrap->md5file(q, digest) < 0) {				sys->print("%s removed\n", p);				continue;			}			str := wrap->md5conv(digest);			str0 := wrap->md5conv(digest0);			# if (str == hd tl lst)			if(str == str0)				continue;			if (listing)				sys->print("%s modified\n", p);			else {				endc := chan of int;				spawn diff(w, p, endc);				<- endc;			}		}	}	wrap->end();}