-- AppendOp.mesa
-- Edited by Schroeder, Wednesday Nov. 5, 1980 2:32 pm PST.
-- Edited by Brotz, September 1, 1980  10:03 AM

DIRECTORY
	crD: FROM "CoreDefs",
	exD: FROM "ExceptionDefs",
	gsD: FROM "GlobalStorageDefs",
	inD: FROM "InteractorDefs",
	intCommon: FROM "IntCommon",
	mfD: FROM "MailFormatDefs",
	opD: FROM "OperationsDefs",
	ovD: FROM "OverviewDefs",
	tsD: FROM "TOCSelectionDefs",
	vmD: FROM "VirtualMgrDefs";

AppendOp: PROGRAM
	IMPORTS crD, gsD, inD, intC:intCommon, mfD, tsD, vmD
	EXPORTS opD
	SHARES opD =

BEGIN

fileAccessError: ERROR = CODE; -- Had error return trying to read or write a file

AppendMailToFileOperation: PUBLIC PROCEDURE [appendFileName: crD.UFilename]
	RETURNS [ovD.ErrorCode] =
BEGIN
-- variables of the procedure
appendFileHandle: crD.UFileHandle;
errorCode, errorCode2: ovD.ErrorCode;
tOCEntry: vmD.TOCFixedPart;
tb: vmD.TOCFixedPartPtr = @tOCEntry;
b, count, bytesToCopy, index: CARDINAL;
messageIndex: vmD.TOCIndex;
aMessageWasCopied: BOOLEAN _ FALSE;

outBufferPage: gsD.MemoryPagePtr;
outBufferString: STRING;  -- turns the BufferPage into a string
outBufferSize: CARDINAL; -- size in bytes, always a multiple of 512
nextOutSlot: CARDINAL;
pageInOutBuffer: crD.PageNumber;

inBufferPage: gsD.MemoryPagePtr;
inBufferString: STRING;  -- turns the BufferPage into a string
nextInSlot: CARDINAL;
pageInInBuffer: crD.PageNumber;

eofPage: crD.PageNumber;
eofByte: CARDINAL;

-- internal procedures of AppendMailToFileOperation

WriteOutputBuffer: PROCEDURE =
	BEGIN
	IF (errorCode _ crD.WritePages[outBufferPage, nextOutSlot, pageInOutBuffer,
												appendFileHandle]) # ovD.ok
		THEN ERROR fileAccessError;
	pageInOutBuffer _ pageInOutBuffer + outBufferSize/512; 
	nextOutSlot _ 0;
	END; -- of WriteOutputBuffer --


ReadInputBuffer: PROCEDURE =
	BEGIN
	[errorCode, ] _ crD.ReadPages[inBufferPage, 512, pageInInBuffer, intC.mailFileHandle];
	IF errorCode # ovD.ok THEN ERROR fileAccessError;
	END; -- of ReadInputBuffer --


APutChar: PROCEDURE [c: CHARACTER] =
	BEGIN
	IF nextOutSlot >= outBufferSize THEN WriteOutputBuffer[];
	outBufferString[nextOutSlot] _ c;
	nextOutSlot _ nextOutSlot +1;
	count _ count +1;
	END;  -- of APutChar --


AGetChar: PROCEDURE RETURNS [CHARACTER] =
	BEGIN --assumes that page boundary won't be crossed
	nextOutSlot _ nextOutSlot + 1;
	RETURN[outBufferString[nextOutSlot - 1]];
	END; -- of AGetChar --

-- code for AppendMailToFileOperation

[errorCode, appendFileHandle] _ crD.OpenFile[intC.user, appendFileName, update];
IF errorCode # ovD.ok THEN RETURN[errorCode];

outBufferSize _ IF tsD.LastSelectedEntry[] < tsD.FirstSelectedEntry[] + 20
						THEN 1024 ELSE 2048;
outBufferPage _ gsD.GetMemoryPages[outBufferSize / 512];
outBufferString _ LOOPHOLE[outBufferPage - 2, STRING];

inBufferPage _ gsD.GetMemoryPages[1];
inBufferString _ LOOPHOLE[inBufferPage - 2, STRING];

BEGIN -- block for exits
ENABLE fileAccessError =>
	BEGIN
	IF errorCode = ovD.diskFull OR errorCode = ovD.fileTooBig THEN
		[] _ crD.UFileTruncate[eofPage, eofByte, appendFileHandle];
      GOTO cleanupAndReturn;
	END;
[errorCode, eofPage, eofByte] _ crD.UFileLength[appendFileHandle];
IF errorCode # ovD.ok THEN GOTO cleanupAndReturn;
IF eofPage # 0 OR eofByte # 0 THEN
	BEGIN --see if target file looks like a mail file
	pageInOutBuffer _ nextOutSlot _ 0;
	[errorCode, ] _ crD.ReadPages[outBufferPage, 512, pageInOutBuffer, appendFileHandle];
	IF errorCode # ovD.ok THEN GOTO cleanupAndReturn;
	IF mfD.ParseStamp[AGetChar, tb] # ovD.ok THEN
		{IF ~inD.AskUserToConfirm[exD.moveTargetExists] THEN GOTO cleanupAndReturn};
	END;
pageInOutBuffer _ eofPage;
nextOutSlot _ eofByte;
IF pageInOutBuffer > 0 AND nextOutSlot > 0 THEN
	BEGIN
	[errorCode, ] _ crD.ReadPages[outBufferPage, 512, pageInOutBuffer, appendFileHandle];
	IF errorCode # ovD.ok THEN GOTO cleanupAndReturn;
	END;
pageInInBuffer _ 77777B;

FOR messageIndex _ tsD.FirstSelectedEntry[], tsD.NextSelectedEntry[messageIndex]
	UNTIL messageIndex = 0 DO -- loop for each message
	vmD.GetTOCFixedPart[messageIndex,tb];
	IF ~tb.deleted THEN
		BEGIN
		IF tb.changed THEN
			BEGIN
			count _ 0;
			mfD.CreateStamp[tb, APutChar];
			b _ tb.firstByte + count;
			tb.firstPage _ tb.firstPage + b/512;
			tb.firstByte _ b MOD 512;
			tb.offsetToHeader _ tb.offsetToHeader - count;
			END;
		IF pageInInBuffer # tb.firstPage THEN
			{pageInInBuffer _ tb.firstPage; ReadInputBuffer[]};
		nextInSlot _ tb.firstByte;
		bytesToCopy _ tb.offsetToHeader + tb.textLength;
		UNTIL bytesToCopy = 0 DO
			IF nextInSlot > 511 THEN --need a new page in the input buffer
				{pageInInBuffer _ pageInInBuffer +1; ReadInputBuffer[]; nextInSlot _ 0};
			DO -- copy input buffer
				count _ MIN[outBufferSize - nextOutSlot, 512 - nextInSlot, bytesToCopy];
				FOR index IN [0 .. count) DO
					outBufferString[nextOutSlot + index] _ inBufferString[nextInSlot + index];
					ENDLOOP;
				nextInSlot _ nextInSlot + count;
				bytesToCopy _ bytesToCopy - count;
				IF (nextOutSlot _ nextOutSlot + count) >= outBufferSize THEN
					WriteOutputBuffer[];
				IF nextInSlot > 511 OR bytesToCopy = 0 THEN EXIT;
				ENDLOOP; -- copy input buffer
			ENDLOOP; -- UNTIL bytesToCopy = 0
		aMessageWasCopied _ TRUE;
		END; -- of ~tb.deleted THEN block
	ENDLOOP; -- loop for each message

IF aMessageWasCopied AND  nextOutSlot # 0 THEN WriteOutputBuffer[];
GOTO cleanupAndReturn;

EXITS
cleanupAndReturn =>
	BEGIN
	errorCode2 _ crD.CloseFile[appendFileHandle];
	IF errorCode = ovD.ok THEN errorCode _ errorCode2; --return the first error
	gsD.ReturnMemoryPages[outBufferSize / 512, outBufferPage];
	gsD.ReturnMemoryPages[1, inBufferPage];
	RETURN[IF (~aMessageWasCopied AND errorCode = ovD.ok)
				THEN ovD.noMessagesMoved ELSE errorCode];
	END;
END; -- of EXITS block
END; -- of AppendMailToFileOperation --


END.	-- of AppendOp --z20461(529)\f1 5801f0