-- edited by Teitelman  June 9, 1982 7:35 am 
-- edited by McGregor  June 11, 1982 11:08 am 

DIRECTORY
    ViewerIO, IO, Rope,
      ViewerClasses, TypeScript; 

ViewerIOImpl: PROGRAM 

    IMPORTS IO, TypeScript  
    EXPORTS IO, ViewerIO
    SHARES IO = 

BEGIN 

Viewer: TYPE = ViewerClasses.Viewer;

ViewerStreamData: TYPE = REF ViewerStreamDataRecord;
ViewerStreamDataRecord: TYPE = RECORD[
    viewer: Viewer,
    echoTo: IO.STREAM _ NIL
    ];

ViewerInStreamProcs: REF IO.StreamProcs _ IO.CreateRefStreamProcs[
    getChar: ViewerGetChar, 
    close: ViewerClose,
    endOf: ViewerEndOf,
    charsAvail: ViewerCharsAvail, 
    setEcho: ViewerSetEcho,
    userAbort: ViewerUserAbort,
    name: "Viewers Input"
    ];
    
ViewerOutStreamProcs: REF IO.StreamProcs _ IO.CreateRefStreamProcs[
    putChar: ViewerPutChar,
    putBlock: ViewerPutBlock,
    close: ViewerClose,
    endOf: ViewerEndOf,
    eraseChar: ViewerEraseChar,
    userAbort: ViewerUserAbort,
    name: "Viewers Output"
];

CreateTTYStreams:  PUBLIC SAFE PROC [name: Rope.ROPE] RETURNS [in: IO.STREAM, out: IO.STREAM]  =
TRUSTED
{[in, out] _ CreateViewerStreams[name];
};


CreateViewerStreams: PUBLIC PROC [name: Rope.ROPE, viewer: Viewer _ NIL, backingFile: Rope.ROPE _ NIL] RETURNS [in: IO.STREAM, out: 
IO.STREAM] =
{OPEN IO;
IF viewer = NIL THEN viewer _ TypeScript.Create[info: [name: name]];
{in _ CreateProcsStream[streamProcs: ViewerInStreamProcs, streamData: NEW[ViewerStreamDataRecord _ [viewer: viewer]] ];
out _ CreateProcsStream[streamProcs: ViewerOutStreamProcs, streamData: NEW[ViewerStreamDataRecord _ [viewer: viewer]] ];
IF backingFile # NIL THEN out _ IO.CreateDribbleStream[stream: out, dribbleTo: IO.CreateFileStream[fileName: backingFile, 
accessOptions: overwrite], flushEveryNChars: 256];
[] _ SetEcho[in, out]; 
};
};

ViewerGetChar:  SAFE PROCEDURE [self: IO.STREAM] RETURNS [char: CHARACTER] = 
TRUSTED
BEGIN
data: ViewerStreamData _ NARROW[self.streamData];
IF data.viewer.destroyed THEN IO.Error[StreamClosed];
char _ TypeScript.GetChar[data.viewer];
IF data.echoTo # NIL THEN IO.PutChar[data.echoTo, char];
END; -- of ViewerGetChar

ViewerPutChar:  SAFE PROCEDURE[self: IO.STREAM, char: CHARACTER] =
TRUSTED
BEGIN
data: ViewerStreamData _ NARROW[self.streamData];
IF data.viewer.destroyed THEN IO.Error[StreamClosed];
TypeScript.PutChar[data.viewer, char];
END; -- of ViewerPutChar

ViewerPutBlock:  SAFE PROCEDURE[self: IO.STREAM, block: REF READONLY TEXT, startIndex: NAT, stopIndexPlusOne: NAT] =
TRUSTED
BEGIN
data: ViewerStreamData _ NARROW[self.streamData];
IF data.viewer.destroyed THEN IO.Error[StreamClosed];
TypeScript.PutText[ts: data.viewer, text: block, start: startIndex, stopPlusOne: stopIndexPlusOne];
END; -- of ViewerPutChar

ViewerReset:  SAFE PROCEDURE[self: IO.STREAM] =
TRUSTED
BEGIN
data: ViewerStreamData _ NARROW[self.streamData];
TypeScript.Reset[data.viewer];
END; -- of ViewerClose

ViewerClose:  SAFE PROCEDURE[self: IO.STREAM, abort: BOOLEAN] =
TRUSTED
BEGIN
data: ViewerStreamData _ NARROW[self.streamData];
IF ~data.viewer.destroyed THEN TypeScript.Destroy[data.viewer];
END; -- of ViewerClose

ViewerEndOf:  SAFE PROCEDURE[self: IO.STREAM] RETURNS [BOOLEAN] = 
CHECKED
BEGIN
data: ViewerStreamData _ NARROW[self.streamData];
IF data.viewer.destroyed THEN IO.Error[StreamClosed];
RETURN[FALSE];
END; -- ViewerEndOf

ViewerCharsAvail:  SAFE PROCEDURE[self: IO.STREAM] RETURNS [BOOLEAN] = 
TRUSTED
BEGIN
data: ViewerStreamData _ NARROW[self.streamData];
IF data.viewer.destroyed THEN IO.Error[StreamClosed];
RETURN[TypeScript.CharsAvailable[data.viewer]];
END; -- ViewerCharsAvail

ViewerEraseChar:  SAFE PROCEDURE[self: IO.STREAM, char: CHARACTER] =
TRUSTED
BEGIN
data: ViewerStreamData _ NARROW[self.streamData];
IF data.viewer.destroyed THEN IO.Error[StreamClosed];
TypeScript.BackSpace[data.viewer];
END; -- of ViewerEraseChar

ViewerSetEcho:  SAFE PROCEDURE[self: IO.STREAM, echoTo: IO.STREAM] RETURNS[oldEcho: IO.STREAM] =
CHECKED
BEGIN
data: ViewerStreamData _ NARROW[self.streamData];
IF data.viewer.destroyed THEN IO.Error[StreamClosed];
oldEcho _ data.echoTo;
data.echoTo _ echoTo;
END; -- of ViewerSetEcho

-- until Andrew gets around to doing this in a more general fashion, this will allow aborting of typeout to a stream that is 
connected to a typescript/exec
ViewerUserAbort: SAFE PROC [self: IO.STREAM] RETURNS [abort: BOOLEAN] =
TRUSTED 
{data: ViewerStreamData _ NARROW[self.streamData];
RETURN[TypeScript.UserAbort[data.viewer]];
};


END.

March 24, 1982 7:46 pm W. Teitelman. Fixed Close to check if viewer already destroyed. Added name argument to CreateRefStreamProcs.
13-Apr-82 14:05:22 W. Teitelman. Added checks for whether viewer was destroyed, and if so, raised IO error
May 27, 1982 2:49 pm W. Teitelman. Changed name of IOStream to IO. Made changes relating to IO being in the Safe language
June 1, 1982 6:01 pm W. Teitelman. Added CheckForAbort.