DIRECTORY
AlpineEnvironment,
Basics USING [bytesPerWord],
FileInstance,
FileLockFormat,
FileLog,
FilePageMgr,
LeaderPage,
LeaderPageFormat,
AlpineLog,
Rope USING [InlineFlatten, Text];
FileLogImpl: PROGRAM
IMPORTS FileInstance, FileLog, FilePageMgr, LeaderPage, AlpineLog, Rope
EXPORTS FileLog
SHARES Rope =
BEGIN OPEN FileLog;
LogCreate: PUBLIC PROCEDURE [fileInstance: FileInstance.Handle, initialSize: PageCount, owner: AlpineEnvironment.OwnerName] =
BEGIN
textOwner: Rope.Text = Rope.InlineFlatten[owner];
length: CARDINAL = textOwner.length;
textBlock: AlpineLog.Block _ [ base: BASE[DESCRIPTOR[textOwner.text]], length: (length+Basics.bytesPerWord-1)/Basics.bytesPerWord];
record: FileLogRecord[create] _ [ volumeID: NULL, fileID: NULL, specifics: create [initialSize: initialSize, owner: [length: length, text: NULL]]];
[volumeID: record.volumeID, fileID: record.fileID] _ FileInstance.GetVolumeIDAndFileID[fileInstance];
[] _ AlpineLog.Write[trans: FileInstance.GetTransHandle[fileInstance], recordType: create, recordData: [base: @record, length: SIZE[FileLogRecord[create]], rest: @textBlock], force: TRUE];
END;
LogDelete: PUBLIC PROCEDURE [fileInstance: FileInstance.Handle] =
BEGIN
record: FileLogRecord[delete] _ [volumeID: NULL, fileID: NULL, specifics: delete []];
[volumeID: record.volumeID, fileID: record.fileID] _ FileInstance.GetVolumeIDAndFileID[fileInstance];
[] _ AlpineLog.Write[trans: FileInstance.GetTransHandle[fileInstance], recordType: delete, recordData: [base: @record, length: SIZE[FileLogRecord[delete]]]];
END;
LogSetSize: PUBLIC PROCEDURE [fileInstance: FileInstance.Handle, old, new: PageCount] =
BEGIN
record: FileLogRecord[setSize] _ [volumeID: NULL, fileID: NULL, specifics: setSize [old: old, new: new]];
[volumeID: record.volumeID, fileID: record.fileID] _ FileInstance.GetVolumeIDAndFileID[fileInstance];
[] _ AlpineLog.Write[trans: FileInstance.GetTransHandle[fileInstance], recordType: setSize, recordData: [base: @record, length: SIZE[FileLogRecord[setSize]]]];
END;
LogWritePages: PUBLIC PROCEDURE [fileInstance: FileInstance.Handle, where: LONG POINTER, pageRun: PageRun, referencePattern: ReferencePattern] RETURNS [recordID: LogRecordID] =
BEGIN
dataBlock: AlpineLog.Block _ [base: where, length: pageRun.count*AlpineEnvironment.wordsPerPage];
record: FileLogRecord[writePages] _ [volumeID: NULL, fileID: NULL, specifics: writePages [pageRun: pageRun, referencePattern: referencePattern, data: NULL]];
[volumeID: record.volumeID, fileID: record.fileID] _ FileInstance.GetVolumeIDAndFileID[fileInstance];
[thisRecord: recordID] _ AlpineLog.Write[trans: FileInstance.GetTransHandle[fileInstance], recordType: writePages, recordData: [base: @record, length: SIZE[FileLogRecord[writePages]], rest: @dataBlock]];
END;
LogReadPages: PUBLIC PROCEDURE [fileInstance: FileInstance.Handle, where: LONG POINTER, pageRun: PageRun, recordID: LogRecordID] RETURNS [referencePattern: ReferencePattern] =
BEGIN
header: FileLogRecord[writePages];
status: AlpineLog.ReadProcStatus;
[status: status] _ AlpineLog.Read[thisRecord: recordID, to: [base: @header, length: SIZE[FileLogRecord[writePages]]]];
IF status=sourceExhausted THEN ERROR;  -- wrong length log record
IF FileInstance.GetFileID[fileInstance] # header.fileID THEN ERROR;  -- wrong file
IF pageRun.firstPage<header.pageRun.firstPage OR pageRun.firstPage+pageRun.count>header.pageRun.firstPage+header.pageRun.count
THEN ERROR;  -- pageRun is not a subinterval of the one contained in the log record
[status: status] _ AlpineLog.Read[thisRecord: recordID, wordsToSkip: SIZE[FileLogRecord[writePages]] + CARDINAL[pageRun.firstPage-header.pageRun.firstPage] * AlpineEnvironment.wordsPerPage, to: [base: where, length: pageRun.count * AlpineEnvironment.wordsPerPage]];
IF status=sourceExhausted THEN ERROR;  -- log record not as long as it says it is
RETURN [header.referencePattern];
END;
LogWriteLeaderPages: PUBLIC PROCEDURE [fileInstance: FileInstance.Handle, leaderPage: LeaderPageFormat.LeaderPageHandle] RETURNS [recordID: LogRecordID] =
BEGIN
dataBlock: AlpineLog.Block _ [base: @leaderPage.record, length: AlpineEnvironment.wordsPerPage*leaderPage.nPages];
record: FileLogRecord[writeLeaderPage] _ [volumeID: NULL, fileID: NULL, specifics: writeLeaderPage [pageCount: leaderPage.nPages, data: NULL]];
[volumeID: record.volumeID, fileID: record.fileID] _ FileInstance.GetVolumeIDAndFileID[fileInstance];
[thisRecord: recordID] _ AlpineLog.Write[trans: FileInstance.GetTransHandle[fileInstance], recordType: writeLeaderPage, recordData: [base: @record, length: SIZE[FileLogRecord[writeLeaderPage]], rest: @dataBlock]];
END;
LogReadLeaderPages: PUBLIC PROCEDURE [fileInstance: FileInstance.Handle, recordID: LogRecordID] RETURNS[ leaderPage: LeaderPageFormat.LeaderPageHandle ] =
BEGIN
header: FileLogRecord[writeLeaderPage];
status: AlpineLog.ReadProcStatus;
[status: status] _ AlpineLog.Read[thisRecord: recordID, to: [base: @header, length: SIZE[FileLogRecord[writeLeaderPage]]]];
IF status=sourceExhausted THEN ERROR;  -- wrong length log record
IF FileInstance.GetFileID[fileInstance] # header.fileID THEN ERROR;  -- wrong file
leaderPage _ LeaderPage.newLeaderPageObject[header.pageCount];
[status: status] _ AlpineLog.Read[thisRecord: recordID, wordsToSkip: SIZE[FileLogRecord[writeLeaderPage]], to: [base: @leaderPage.record, length: AlpineEnvironment.wordsPerPage*header.pageCount]];
IF status#normal THEN ERROR;  -- log record not as long as it says it is
END;

LogChangeHWM: PUBLIC PROCEDURE [fileInstance: FileInstance.Handle, oldHWM, newHWM: PageCount] = 
BEGIN
record: FileLogRecord[changeHWM] _ [volumeID: NULL, fileID: NULL, specifics: changeHWM [oldHWM: oldHWM, newHWM: newHWM]];
[volumeID: record.volumeID, fileID: record.fileID] _ FileInstance.GetVolumeIDAndFileID[fileInstance];
[] _ AlpineLog.Write[trans: FileInstance.GetTransHandle[fileInstance], recordType: changeHWM, recordData: [base: @record, length: SIZE[FileLogRecord[changeHWM]]]];
END;

LogWritePagesToBase: PUBLIC PROCEDURE [fileInstance: FileInstance.Handle, pageRun: PageRun] = 
BEGIN
record: FileLogRecord[writePagesToBase] _ [volumeID: NULL, fileID: NULL, specifics: writePagesToBase[pageRun: pageRun]];
[volumeID: record.volumeID, fileID: record.fileID] _ FileInstance.GetVolumeIDAndFileID[fileInstance];
[] _ AlpineLog.Write[trans: FileInstance.GetTransHandle[fileInstance], recordType: writePagesToBase, recordData: [base: @record, length: SIZE[FileLogRecord[writePagesToBase]]]];
END;

LogFileLock: PUBLIC PROCEDURE [fileInstance: FileInstance.Handle] =
BEGIN
lockSubID: FileLockFormat.FileLockSubID = [file[]];
record: FileLogRecord[lock] _ [volumeID: NULL, fileID: NULL, specifics: lock [lockSubID: LOOPHOLE[lockSubID]]];
[volumeID: record.volumeID, fileID: record.fileID] _ FileInstance.GetVolumeIDAndFileID[fileInstance];
[] _ AlpineLog.Write[trans: FileInstance.GetTransHandle[fileInstance], recordType: lock, recordData: [base: @record, length: SIZE[FileLogRecord[lock]]]];
END;


FileRecoveryProc: AlpineLog.RecoveryProc --[record, type, trans, outcome]-- =
BEGIN
fileInstance: FileInstance.Handle;
header: FileLogRecord;
wordsRead: CARDINAL;
exists: BOOLEAN _ TRUE;
IF type NOT IN DefinedFileRecord THEN ERROR;
[wordsRead: wordsRead] _ AlpineLog.ReadForRecovery[thisRecord: record, to: [base: @header, length: SIZE[FileLogRecord]]];
IF wordsRead<SIZE[FileLogRecord[delete]] THEN ERROR;  -- log record too short
fileInstance _ FileInstance.Register[trans: trans, volumeID: header.volumeID, fileID: header.fileID];
[] _ FilePageMgr.GetSize[FileInstance.GetFileHandle[fileInstance] !
FilePageMgr.NoSuchFile => {exists _ FALSE; CONTINUE}];
IF exists THEN WITH r: header SELECT type FROM
create =>
BEGIN
IF wordsRead<SIZE[FileLogRecord[create]] THEN ERROR;  -- log record too short
RecoverCreate[fileInstance: fileInstance, initialSize: r.initialSize, outcome: outcome];
END;
delete =>
BEGIN
IF wordsRead<SIZE[FileLogRecord[delete]] THEN ERROR;  -- log record too short
RecoverDelete[fileInstance: fileInstance, outcome: outcome];
END;
setSize =>
BEGIN
IF wordsRead<SIZE[FileLogRecord[setSize]] THEN ERROR;  -- log record too short
RecoverSetSize[fileInstance: fileInstance, old: r.old, new: r.new, outcome: outcome];
END;
writePages =>
BEGIN
IF wordsRead<SIZE[FileLogRecord[writePages]] THEN ERROR;  -- log record too short
RecoverWritePages[fileInstance: fileInstance, recordID: record, pageRun: r.pageRun, outcome: outcome];
END;
writeLeaderPage =>
BEGIN
IF wordsRead<SIZE[FileLogRecord[writeLeaderPage]] THEN ERROR;  -- log record too short
RecoverWriteLeaderPage[fileInstance: fileInstance, recordID: record, outcome: outcome];
END;
lock =>
BEGIN
IF wordsRead<SIZE[FileLogRecord[lock]] THEN ERROR;  -- log record too short
RecoverLock[fileInstance: fileInstance, lockSubID: r.lockSubID, outcome: outcome];
END;
changeHWM =>
BEGIN
IF wordsRead<SIZE[FileLogRecord[changeHWM]] THEN ERROR;  -- log record too short
END;
writePagesToBase =>
BEGIN
IF wordsRead<SIZE[FileLogRecord[writePagesToBase]] THEN ERROR;  -- log record too short
END;
ENDCASE => ERROR;
FileInstance.SetMaxDeltaVersion[fileInstance, 1];
FileInstance.Unregister[fileInstance];
END;



FOR type: DefinedFileRecord IN DefinedFileRecord DO
AlpineLog.RegisterRecoveryProc[type, FileRecoveryProc];
ENDLOOP;
END.
ŠFileLogImpl.mesa
Copyright c 1985 by Xerox Corporation.  All rights reserved.
Last edited by:
Taft on April 10, 1983 3:16 pm
MBrown on January 30, 1984 1:48:20 pm PST
Hauser, March 7, 1985 2:57:05 pm PST
Carl Hauser, March 18, 1986 10:07:37 am PST

FileLog.
Internal procedures
Attempt to read the longest possible FileLogRecord, and make sure it is at least as long as the shortest possible FileLogRecord.
Recover the update only if the file still exists, under the assumption that if it does not exist then it must have been deleted by some later committed transaction. GetSize is an efficient way to check for the existence of a file because FilePageMgr caches the file's existence and size.
owner is not actually needed for recovery, so omit this:
owner: OwnerName;
Fetch: SAFE PROCEDURE RETURNS [c: CHAR] = TRUSTED
{c _ r.owner.text[index]; index _ index+1};
index: CARDINAL _ 0;
owner _ Rope.FromProc[len: r.owner.length, p: Fetch];
Nothing to be done: the change is also represented in a writeLeaderPage type log record where it will be taken care of.
Nothing to be done: the change is already represented in the file.
Unregister to balance the above Register, so the fileInstance use count will be zero when recovery finished.  Pretend that an update has occurred (even if it hasn't) so that the fileInstance will stay around.
Module initialization
Hauser, March 7, 1985 2:56:28 pm PST
Added copyright.

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