-- Copyright (C) 1981, 1984, 1985 by Xerox Corporation. All rights reserved. -- HeapXDefs.mesa, private DEFS for heap storage -- HGM, 15-Sep-85 12:51:50 -- Andrew Birrell 24-Feb-81 15:47:29 -- -- Brenda Hankins 15-Aug-84 14:11:34 alter WriterData def. DIRECTORY HeapDefs USING [ObjectNumber, ObjectOffset], VMDefs USING [FullAddress, PageAddress, Page, PageIndex, LookAheadCount]; HeapXDefs: DEFINITIONS = BEGIN -- Layout of objects on disk -- ObjectHeader: TYPE = MACHINE DEPENDENT RECORD [ size: CARDINAL, number: HeapDefs.ObjectNumber]; PageHeader: TYPE = MACHINE DEPENDENT RECORD [offset: HeapDefs.ObjectOffset]; -- Writer -- WriterHandle: TYPE = LONG POINTER TO WriterData; WriterData: TYPE = MONITORED RECORD [ next: WriterHandle, -- free chain -- page: VMDefs.Page, object: HeapDefs.ObjectNumber, offset: HeapDefs.ObjectOffset, maxOffset: HeapDefs.ObjectOffset, -- max offset if reWriting start: VMDefs.PageAddress, -- first value of wPos.page -- reWriting: BOOLEAN, base: VMDefs.PageIndex, --start of sub-object data-- wPos: VMDefs.FullAddress, objectHead: LONG POINTER TO ObjectHeader]; -- Reader -- ReaderHandle: TYPE = LONG POINTER TO ReaderData; ReaderData: TYPE = MONITORED RECORD [ next: ReaderHandle, page: VMDefs.Page, object: HeapDefs.ObjectNumber, offset: HeapDefs.ObjectOffset, where: VMDefs.FullAddress, end: BOOLEAN, stopped: BOOLEAN, canStart: CONDITION]; lookAhead: VMDefs.LookAheadCount = 2; -- used by readers and compactor -- -- Compactor interlock -- StopAllReaders: PROCEDURE [HeapDefs.ObjectNumber]; -- Stops any reader which is reading this object. -- RestartAllReaders: PROCEDURE [HeapDefs.ObjectNumber]; -- Allows stopped readers to continue; the object may have moved in the -- heap. -- StopReader: PROCEDURE [from: ReaderHandle]; -- Tells the reader to stop. -- RestartReader: PROCEDURE [from: ReaderHandle]; -- Tells the reader to restart and re-calculate its position within the -- heap, since the object may have moved. -- END.