-- AccessOp.mesa
-- edited by Schroeder, May 4, 1981  3:09 PM.
-- edited by Brotz, March 4, 1983  9:54 AM
-- edited by Levin, February 24, 1981  4:51 PM.

DIRECTORY
  AltoFile USING [DiskFull],
  BodyDefs USING [ItemHeader],
  csD: FROM "CoreStreamDefs" USING [Checkpoint, Destroy, EndOfStream, GetLength,
    GetPosition, MapPageByteToPosition, MapPositionToPageByte, Open, Position, Read,
    Reset, SetPosition, StreamHandle, Write, WriteBlock],
  exD: FROM "exceptionDefs" USING [AppendExceptionToExceptionLine,
    AppendStringToExceptionLine, badCredentialsSemi, badServerNameSemi, busySemi,
    cantConnect, continuationHeader, DisplayExceptionLine, dots, dotsDidntRespond,
    dotsEmpty, emptySemi, Exception, ExceptionLineOverflow, failedSemi,
    FlashExceptionsRegion, GetExceptionString, loginTryAgain, newMailOverfill, nil,
    noMailboxes, noNewMail, overflow, semi, SysBug, tocOverflow, unknownErrorSemi],
  Inline USING [LowHalf],
  MailParseDefs USING [endOfInput],
  mfD: FROM "MailFormatDefs" USING [CreateStamp, ParseHeaderForTOC, ParseStamp],
  opD: FROM "OperationsDefs" USING [maxTOCStringLength],
  Process USING [Yield],
  RetrieveDefs USING [AccessProcs, Failed, FailureReason, Handle, MailboxState,
    NextServer, ServerName, ServerState],
  String USING [AppendNumber, EquivalentString],
  vmD: FROM "VirtualMgrDefs" USING [CheckpointDisplayMessage, DMList, ExtendTOC,
    FirstFreeTOCIndex, GetTOCFixedPart, TOCFixedPart, TOCFixedPartPtr, TOCHandle,
    TOCOverflow],
  VMDefs USING [AllocatePage, Error, Page, pageByteSize, Release];


AccessOp: PROGRAM
  IMPORTS AltoFile, csD, exD, Inline, mfD, Process, RetrieveDefs, String, vmD, VMDefs
  EXPORTS opD =

BEGIN


AccessNewMailOperation: PUBLIC PROCEDURE
    [toc: vmD.TOCHandle, key: CARDINAL, retrieveHandle: RetrieveDefs.Handle,
    registry: STRING, ignoreUserFeedback: BOOLEAN _ FALSE,
    deleteEachMessage: BOOLEAN _ FALSE]
  RETURNS [messagesRead: BOOLEAN] =
-- Gets new messages from the user's mailbox(es) through "retrieveHandle", appends them
--   to the mail file "toc", and updates the TOC.  If "deleteEachMessage" is FALSE, then
--   each mailbox in turn is flushed only after successfully retrieveing all messages in
--   that mailbox.  If "deleteEachMessage" is TRUE, then each message is deleted from its
--   mailbox after successful retrieval of that message.
BEGIN
breakBuffers: [0 .. 177777B / VMDefs.pageByteSize) = 125;
buffer: VMDefs.Page _ NIL;
mailFileSH: csD.StreamHandle _ NIL;
flashWanted: BOOLEAN _ FALSE;
nextCharLimit: CARDINAL;
charCount: CARDINAL;

BoxNextChar: PROCEDURE RETURNS [lastChar: CHARACTER] =
  BEGIN
  IF charCount >= nextCharLimit THEN lastChar _ MailParseDefs.endOfInput 
  ELSE lastChar _ csD.Read[mailFileSH ! csD.EndOfStream =>
    {nextCharLimit _ charCount; lastChar _ MailParseDefs.endOfInput; CONTINUE}];
  charCount _ charCount + 1;
  END;  -- of BoxNextChar --

BoxPutChar: PROCEDURE [c: CHARACTER] = {csD.Write[mailFileSH, c]};

BoxPositionNextChar: PROCEDURE [page, byte, limit: CARDINAL] =
  BEGIN
  nextCharLimit _ limit;
  charCount _ 0;
  csD.SetPosition[mailFileSH, csD.MapPageByteToPosition[page, byte]];
  END;  -- of BoxPositionNextChar --

lastLineUsed: [0 .. 2] _ 0;

ReportProgressString: PROCEDURE [s: STRING] =
  BEGIN
  IF ignoreUserFeedback THEN RETURN;
  lastLineUsed _ 1;
  exD.AppendStringToExceptionLine[s, 1
    ! exD.ExceptionLineOverflow => CONTINUE ];
  END;  -- of ReportProgressString --

ReportProgress: PROCEDURE [e: exD.Exception] =
  BEGIN
  IF ignoreUserFeedback THEN RETURN;
  lastLineUsed _ 1;
  exD.AppendExceptionToExceptionLine[e, 1
    ! exD.ExceptionLineOverflow => CONTINUE ];
  END;  -- of ReportProgress --

lastException: exD.Exception _ exD.nil;

ReportException: PROCEDURE [e: exD.Exception,
    f: {flash, dontFlash} _ dontFlash] =
  BEGIN
  IF ignoreUserFeedback THEN RETURN;
  IF lastLineUsed = 2
    THEN exD.DisplayExceptionLine[lastException, 1]
    ELSE lastLineUsed _ lastLineUsed + 1;
  exD.DisplayExceptionLine[e, lastLineUsed];
  lastException _ e;
  IF f = flash THEN flashWanted _ TRUE;
  END;  -- of ReportException --


-- Code for AccessNewMailOperation

messagesRead _ FALSE;

BEGIN  -- for EXITS --

serverKnown: BOOLEAN _ FALSE;
utilityString: STRING = [opD.maxTOCStringLength];
  -- [MAX[opD.maxTOCStringLength, BodyDefs.maxRNameLength, 60]]
tOCEntry: vmD.TOCFixedPart;
tb: vmD.TOCFixedPartPtr = @tOCEntry;

tb.deleted _ tb.changed _ tb.seen _ FALSE;
tb.mark _ ' ;
tb.offsetToHeader _ 0;

SELECT RetrieveDefs.MailboxState[retrieveHandle] FROM
  badName, badPwd => GOTO credentialsError;
  cantAuth => GOTO noServers; 
  ENDCASE; --ok to try

-- Flush buffers on the mail file held by all displayed messages.
FOR dmList: vmD.DMList _ toc.dmList, dmList.next UNTIL dmList = NIL DO
  IF dmList.dm # NIL THEN vmD.CheckpointDisplayMessage[dmList.dm, key];
  ENDLOOP;

mailFileSH _ csD.Open[fh: toc.mailFile, type: byte, mode: append];
buffer _ VMDefs.AllocatePage[];

DO -- next server
  ENABLE
  BEGIN
  VMDefs.Error =>
    BEGIN
    UNTIL RetrieveDefs.NextServer[retrieveHandle].noMore DO ENDLOOP;
    IF reason = resources THEN GO TO FullDisk;
    END;
  AltoFile.DiskFull =>
    BEGIN
    UNTIL RetrieveDefs.NextServer[retrieveHandle].noMore DO ENDLOOP;
    GO TO FullDisk;
    END;
  END;  -- ENABLE --

  messages: CARDINAL _ 0;
  connected, archivedReported: BOOLEAN _ FALSE;
  retProcs: RetrieveDefs.AccessProcs;
  whyFailed: RetrieveDefs.FailureReason;

  noMore: BOOLEAN;
  serverState: RetrieveDefs.ServerState;
  Process.Yield[];
  [noMore, serverState, retProcs] _ RetrieveDefs.NextServer[retrieveHandle];
  IF noMore THEN EXIT;
  serverKnown _ TRUE;
  RetrieveDefs.ServerName[retrieveHandle, utilityString];
  ReportProgressString[utilityString];
  IF String.EquivalentString[utilityString, registry]
    THEN ReportProgressString[" inbox server "L];
  IF serverState # notEmpty THEN
    BEGIN
    ReportProgress
      [IF serverState = empty THEN exD.dotsEmpty ELSE exD.dotsDidntRespond];
    LOOP;
    END;

  DO -- next message
    firstChunk: BOOLEAN _ TRUE;
    msgExists, archived, deleted: BOOLEAN;
    item: BodyDefs.ItemHeader;

    [msgExists, archived, deleted] _ retProcs.nextMessage[retrieveHandle
      ! RetrieveDefs.Failed => {whyFailed _ why; GOTO retrieveError} ];
    IF NOT connected THEN {connected _ TRUE; ReportProgress[exD.dots]};
    IF NOT msgExists THEN EXIT;
    IF archived AND NOT archivedReported THEN
      {archivedReported _ TRUE; ReportProgressString["archived messages .. "L]};
    IF deleted THEN LOOP;
    DO
      item _ retProcs.nextItem[retrieveHandle
        ! RetrieveDefs.Failed => {whyFailed _ why; GOTO retrieveError} ];
      IF item.type = Text OR item.type = LastItem THEN EXIT;
      ENDLOOP;
    IF item.type = LastItem THEN LOOP;
    Process.Yield[];

    UNTIL item.length = 0 DO -- message chunks
      breakBytes: CARDINAL = breakBuffers * VMDefs.pageByteSize;
      tb.textLength _ IF item.length <= breakBytes 
        THEN Inline.LowHalf[item.length] ELSE breakBytes;
      item.length _ item.length - tb.textLength;
      IF firstChunk THEN mfD.CreateStamp[tb, BoxPutChar]
      ELSE BEGIN
        exD.GetExceptionString[exD.continuationHeader, utilityString];
        tb.textLength _ tb.textLength + utilityString.length;
        mfD.CreateStamp[tb, BoxPutChar];
        csD.WriteBlock[mailFileSH, @utilityString.text, 0, utilityString.length];
        END;
      firstChunk _ FALSE;
      FOR blockCounter: CARDINAL IN [0 .. breakBuffers) DO -- next block
        bytes: CARDINAL = retProcs.nextBlock
          [retrieveHandle, DESCRIPTOR[@buffer.chars, VMDefs.pageByteSize]
            ! RetrieveDefs.Failed => {whyFailed _ why; GOTO retrieveError}];
        IF bytes = 0 THEN EXIT;
        csD.WriteBlock[mailFileSH, buffer, 0, bytes];
        ENDLOOP; -- next block
      ENDLOOP; -- message chunk

    IF deleteEachMessage THEN
      BEGIN
      csD.Checkpoint[mailFileSH];
      WITH gvRetProcs: retProcs SELECT FROM
        GV => gvRetProcs.deleteMessage[retrieveHandle];
        ENDCASE;
      END;
    messages _ messages + 1;

    REPEAT
    retrieveError =>
      BEGIN 
      IF NOT connected THEN ReportProgress[exD.dots];
      ReportProgress[ SELECT whyFailed FROM
        communicationFailure => exD.failedSemi,
        noSuchServer => exD.badServerNameSemi,
        connectionRejected => exD.busySemi,
        badCredentials => exD.badCredentialsSemi,
        ENDCASE => exD.unknownErrorSemi ];      
      csD.Reset[mailFileSH];
      csD.Checkpoint[mailFileSH];
      LOOP; -- goes to start of next server loop
      END;
    ENDLOOP; -- next message

  csD.Checkpoint[mailFileSH];
  retProcs.accept[retrieveHandle ! RetrieveDefs.Failed => CONTINUE ];
  IF messages = 0 THEN ReportProgress[exD.emptySemi]
  ELSE BEGIN
    numString: STRING = [6];
    String.AppendNumber[numString,messages,10];
    ReportProgressString[numString];
    ReportProgress[exD.semi];
    messagesRead _ TRUE;
    END;
  REPEAT
  FullDisk =>
    BEGIN
    ReportProgress[exD.overflow];
    csD.Reset[mailFileSH];
    csD.Checkpoint[mailFileSH];
    ReportException[exD.newMailOverfill];
    END;
  ENDLOOP; -- next server

VMDefs.Release[buffer];
buffer _ NIL;
IF NOT serverKnown THEN GOTO noMailboxes;

IF messagesRead THEN
  BEGIN -- extend toc to include new messages
  p: csD.Position;
  vmD.GetTOCFixedPart[toc, key, vmD.FirstFreeTOCIndex[toc, key] - 1, tb];
  BoxPositionNextChar[tb.firstPage, tb.firstByte + tb.offsetToHeader + tb.textLength, 24];
  WHILE (p _ csD.GetPosition[mailFileSH]) < csD.GetLength[mailFileSH] DO
    [tb.firstPage, tb.firstByte] _ csD.MapPositionToPageByte[p];
    IF ~mfD.ParseStamp[BoxNextChar, tb] THEN exD.SysBug[];
    BoxPositionNextChar[tb.firstPage, tb.firstByte + tb.offsetToHeader, tb.textLength];
    mfD.ParseHeaderForTOC[utilityString, BoxNextChar];
    vmD.ExtendTOC[toc, key, tb, utilityString
      ! vmD.TOCOverflow => GO TO tocError;
        VMDefs.Error => IF reason = resources THEN GO TO tocError;
        AltoFile.DiskFull => GO TO tocError];
    BoxPositionNextChar[tb.firstPage, tb.firstByte+tb.offsetToHeader + tb.textLength, 24];
    ENDLOOP;
  END
ELSE ReportException[exD.noNewMail];
  
EXITS
noMailboxes => ReportException[exD.noMailboxes, flash];
credentialsError => ReportException[exD.loginTryAgain, flash];
noServers => ReportException[exD.cantConnect, flash];
tocError => ReportException[exD.tocOverflow, flash];
END; -- of EXITS block

IF mailFileSH # NIL THEN csD.Destroy[mailFileSH];
IF buffer # NIL THEN VMDefs.Release[buffer];
IF flashWanted AND ~ignoreUserFeedback THEN exD.FlashExceptionsRegion[];
END; -- of AccessNewMailOperation --


END.  -- of AccessOp --

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