ref: c116550e6a41572796e4db65e4f6acbcb3d9d6f8
dir: /appl/collab/servers/wbsrv.b/
implement Service; include "sys.m"; sys: Sys; include "draw.m"; draw: Draw; Chans, Display, Image, Rect, Point : import draw; include "../service.m"; WBW : con 234; WBH : con 279; init(nil : list of string) : (string, string, ref Sys->FD) { sys = load Sys Sys->PATH; draw = load Draw Draw->PATH; if (draw == nil) return ("cannot load Draw module", nil, nil); p := array [2] of ref Sys->FD; if (sys->pipe(p) == -1) return (sys->sprint("cannot create pipe: %r"), nil, nil); display := Display.allocate(nil); if (display == nil) return (sys->sprint("cannot allocate display: %r"), nil, nil); r := Rect(Point(0,0), Point(WBW, WBH)); wb := display.newimage(r, Draw->CMAP8, 0, Draw->White); if (wb == nil) return (sys->sprint("cannot allocate whiteboard image: %r"), nil, nil); nextmsg = ref Msg (nil, nil); spawn wbsrv(p[1], wb); return (nil, "/chan", p[0]); } wbsrv(fd : ref Sys->FD, wb: ref Image) { sys->pctl(Sys->FORKNS, nil); sys->unmount(nil, "/chan"); sys->bind("#s", "/chan", Sys->MREPL); bit := sys->file2chan("/chan", "wb.bit"); strokes := sys->file2chan("/chan", "strokes"); hangup := chan of int; spawn export(fd, hangup); nwbbytes := draw->bytesperline(wb.r, wb.depth) * wb.r.dy(); bithdr := sys->aprint("%11s %11d %11d %11d %11d ", wb.chans.text(), 0, 0, WBW, WBH); for (;;) alt { <-hangup => sys->print("whiteboard:hangup\n"); return; (offset, count, fid, r) := <-bit.read => if (r == nil) { closeclient(fid); continue; } c := getclient(fid); if (c == nil) { # new client c = newclient(fid); data := array [len bithdr + nwbbytes] of byte; data[0:] = bithdr; wb.readpixels(wb.r, data[len bithdr:]); c.bitdata = data; } if (offset >= len c.bitdata) { rreply(r, (nil, nil)); continue; } rreply(r, (c.bitdata[offset:], nil)); (offset, data, fid, w) := <-bit.write => if (w != nil) wreply(w, (0, "permission denied")); (offset, count, fid, r) := <-strokes.read => if (r == nil) { closeclient(fid); continue; } c := getclient(fid); if (c == nil) { c = newclient(fid); c.nextmsg = nextmsg; } d := c.nextmsg.data; if (d == nil) { c.pending = r; c.pendlen = count; continue; } c.nextmsg = c.nextmsg.next; rreply(r, (d, nil)); (offset, data, fid, w) := <-strokes.write => if (w == nil) { closeclient(fid); continue; } err := drawstrokes(wb, data); if (err != nil) { wreply(w, (0, err)); continue; } wreply(w, (len data, nil)); writeclients(data); } } rreply(rc: chan of (array of byte, string), reply: (array of byte, string)) { alt { rc <-= reply =>; * =>; } } wreply(wc: chan of (int, string), reply: (int, string)) { alt { wc <-= reply=>; * =>; } } export(fd : ref Sys->FD, done : chan of int) { sys->export(fd, "/", Sys->EXPWAIT); done <-= 1; } Msg : adt { data : array of byte; next : cyclic ref Msg; }; Client : adt { fid : int; bitdata : array of byte; # bit file client nextmsg : ref Msg; # strokes file client pending : Sys->Rread; pendlen : int; }; nextmsg : ref Msg; clients : list of ref Client; newclient(fid : int) : ref Client { c := ref Client(fid, nil, nil, nil, 0); clients = c :: clients; return c; } getclient(fid : int) : ref Client { for(cl := clients; cl != nil; cl = tl cl) if((c := hd cl).fid == fid) return c; return nil; } closeclient(fid : int) { nl: list of ref Client; for(cl := clients; cl != nil; cl = tl cl) if((hd cl).fid != fid) nl = hd cl :: nl; clients = nl; } writeclients(data : array of byte) { nm := ref Msg(nil, nil); nextmsg.data = data; nextmsg.next = nm; for(cl := clients; cl != nil; cl = tl cl){ if ((c := hd cl).pending != nil) { n := c.pendlen; if (n > len data) n = len data; alt{ c.pending <-= (data[0:n], nil) => ; * => ; } c.pending = nil; c.nextmsg = nm; } } nextmsg = nm; } # data: colour width p0 p1 pn* drawstrokes(wb: ref Image, data : array of byte) : string { (n, toks) := sys->tokenize(string data, " "); if (n < 6 || n & 1) return "bad data"; colour, width, x, y : int; (colour, toks) = (int hd toks, tl toks); (width, toks) = (int hd toks, tl toks); (x, toks) = (int hd toks, tl toks); (y, toks) = (int hd toks, tl toks); pen := wb.display.newimage(Rect(Point(0,0), Point(1,1)), Draw->CMAP8, 1, colour); p0 := Point(x, y); while (toks != nil) { (x, toks) = (int hd toks, tl toks); (y, toks) = (int hd toks, tl toks); p1 := Point(x, y); # could use poly() instead of line() wb.line(p0, p1, Draw->Endsquare, Draw->Endsquare, width, pen, pen.r.min); p0 = p1; } return nil; }