PACKET dos manager multi DEFINES             (* Copyright (C) 1985, 86, 87 *)
                                             (* Frank Klapper              *)
  provide channel,                           (* 16.10.87                   *)
  dos manager:
 
LET std archive channel = 31,

    ack              = 0,
    second phase ack = 5,
    false code       = 6,

    fetch code       = 11,
    save code        = 12,
    exists code      = 13,
    erase code       = 14,
    list code        = 15,
    all code         = 17,
    clear code       = 18,
    reserve code     = 19,
    free code        = 20,
    check read code  = 22,
    format code      = 23,

    log code         = 78,

    quote            = """";

BOUND STRUCT (TEXT name, pass) VAR msg;

TASK VAR order task;

INT VAR dos channel;

INT VAR fetch save modus;

REAL VAR last access time := 0.0;

TASK VAR disk owner := niltask; 

TEXT VAR save file name;

PROC provide channel (INT CONST channel):
  dos channel := channel

END PROC provide channel;

IF hd version
  THEN provide channel (29)
  ELSE provide channel (std archive channel)
FI;

PROC dos manager:
  dos manager (dos channel)

END PROC dos manager;

PROC dos manager (INT CONST channel):
  dos channel := channel;
  task password ("-");
  global manager
        (PROC (DATASPACE VAR, INT CONST, INT CONST, TASK CONST) dos manager) 

END PROC dos manager;

PROC dos manager (DATASPACE VAR ds, INT CONST order code, phase,
                  TASK CONST from task):
  enable stop;
  order task := from task;
  msg := ds;
  IF NOT (order task = disk owner) AND 
     order code <> free code AND order code <> reserve code
    THEN errorstop ("DOS nicht angemeldet")
  FI;
  IF order task = disk owner
    THEN last access time := clock (1)
  FI;
  SELECT order code OF 
    CASE fetch code     : fetch file 
    CASE save code      : save file
    CASE erase code     : erase file
    CASE clear code     : clear disk
    CASE exists code    : exists file
    CASE list code      : list disk
    CASE all code       : deliver directory
    CASE reserve code   : reserve
    CASE free code      : free
    CASE check read code: check
    CASE format code    : format
    CASE log code       : send log
    OTHERWISE errorstop ("unbekannter Auftrag für Task: " + name (myself))
  END SELECT.

fetch file:
  fetch (dos name (msg.name, read modus), ds, fetch save modus);
  manager ok (ds).

check:
  check file (dos name (msg.name, read modus));
  manager message (expanded name (msg.name, read modus) + " ohne Fehler gelesen"). 

format:
  IF phase = 1
    THEN manager question ("Diskette formatieren")
    ELSE format dos disk (int (msg.name));
         manager ok (ds)
  FI.

save file:
  IF phase = 1
    THEN save first phase
    ELSE save second phase
  FI.

save first phase:
  save file name := dos name (msg.name, write modus);
  IF dos file exists (save file name)
    THEN manager question (expanded name (msg.name, write modus) + " auf der MS-DOS Disk ueberschreiben")
    ELSE send (order task, second phase ack, ds)
  FI.

save second phase:
  IF dos file exists (save file name)
    THEN erase dos file (save file name)
  FI;
  save (save file name, ds, fetch save modus);
  forget (ds) ;
  ds := nilspace ;
  manager ok (ds).

clear disk: 
  IF phase = 1
    THEN manager question ("Diskette loeschen")
    ELSE clear dos disk;
         manager ok (ds)
  FI.

erase file:
  IF dos file exists (dos name (msg.name, read modus))
    THEN IF phase = 1
           THEN manager question (expanded name (msg.name, TRUE) + " auf der MS-DOS Disk loeschen")
           ELSE erase dos file (dos name (msg.name, read modus));
                manager ok (ds)
         FI
    ELSE manager message ("die Datei " + expanded name (msg.name, TRUE) + " gibt es nicht auf der MS-DOS Disk")
  FI.
 
exists file:
  IF dos file exists (dos name (msg.name, read modus))
    THEN manager ok (ds)
    ELSE send (order task, false code, ds)
  FI.

list disk:
  dos list (ds);
  manager ok (ds).

send log:
  forget (ds);
  ds := old ("logbuch");
  manager ok (ds).

deliver directory:
  forget (ds);
  ds := nilspace;
  BOUND THESAURUS VAR all names := ds;
  all names := all dos files;
  manager ok (ds).

reserve:
  IF reserve or free permitted
    THEN continue channel (dos channel);
         disk owner := from task;
         fetch save modus := save fetch mode (msg.name);
         open dos disk (path (msg.name));
         forget ("logbuch", quiet);
         manager ok (ds)
    ELSE errorstop ("Archivlaufwerk wird von Task """+ name (disk owner) + """ benutzt")
  FI.

reserve or free permitted :
  from task = disk owner OR last access more than five minutes ago
  OR disk owner = niltask OR NOT
  (exists (disk owner) OR station(disk owner) <> station (myself)).

last access more than five minutes ago :
  abs (last access time - clock (1)) > 300.0.

free: 
  IF reserve or free permitted
    THEN close dos disk;
         disk owner := niltask;
         break (quiet);
         manager ok (ds)
    ELSE manager message ("DOS nicht angemeldet")
  FI.

END PROC dos manager;

PROC manager ok (DATASPACE VAR ds):
  send (order task, ack, ds);
  last access time := clock (1).

END PROC manager ok;

TEXT PROC expanded name (TEXT CONST name, BOOL CONST status):
  text (quote + dos name (name, status) + quote, 14)

END PROC expanded name;

END PACKET dos manager multi;