sharedobj/src/ObjectInfo.i3


                            -*- Mode: Modula-3 -*- 
 * 
 * For information about this program, contact Blair MacIntyre            
 * (bm@cs.columbia.edu) or Steven Feiner (feiner@cs.columbia.edu)         
 * at the Computer Science Dept., Columbia University,                    
 * 1214 Amsterdam Ave. Mailstop 0401, New York, NY, 10027.                
 *                                                                        
 * Copyright (C) 1995, 1996 by The Trustees of Columbia University in the 
 * City of New York.  Blair MacIntyre, Computer Science Department.       
 * See file COPYRIGHT-COLUMBIA for details.
 * 
 * Author          : Blair MacIntyre
 * Created On      : Tue Apr 25 13:50:10 1995
 * Last Modified By: Blair MacIntyre
 * Last Modified On: Fri Nov 22 14:00:34 1996
 * Update Count    : 64
 * 
 * $Source: /opt/cvs/cm3/doc/help/gen_html/sharedobj/src/ObjectInfo.i3.html,v $
 * $Date: 2010-04-29 17:19:55 $
 * $Author: wagner $
 * $Revision: 1.5 $
 * 
 * $Log: not supported by cvs2svn $
 * Revision 1.4.2.1  2010-04-15 21:00:25  wagner
 * update generated HTML doc to RC5
 *
 * Revision 1.2  2001/12/02 13:41:16  wagner
 * add copyright notes, fix overrides for cm3, and make everything compile(except tests)
 *
 * added: sharedobj/COPYRIGHT-COLUMBIA
 * added: sharedobj/src/COPYRIGHT-COLUMBIA
 * modified: sharedobj/src/LocalObjectSpace.i3
 * modified: sharedobj/src/LocalObjectSpace.m3
 * modified: sharedobj/src/Message.i3
 * modified: sharedobj/src/Message.m3
 * modified: sharedobj/src/ObjCopy.i3
 * modified: sharedobj/src/ObjCopy.m3
 * modified: sharedobj/src/ObjectInfo.i3
 * modified: sharedobj/src/ObjectInfo.m3
 * modified: sharedobj/src/ObjectSpace.i3
 * modified: sharedobj/src/ObjectSpace_FindObjCallBack_v1.i3
 * modified: sharedobj/src/ObjectSpace_FindObjCallBack_v1.m3
 * modified: sharedobj/src/ObjectSpace_FindObjCallBack_v2.i3
 * modified: sharedobj/src/ObjectSpace_FindObjCallBack_v2.m3
 * modified: sharedobj/src/ObjectSpace_T_v1.i3
 * modified: sharedobj/src/ObjectSpace_T_v1.m3
 * modified: sharedobj/src/ObjectSpace_T_v2.i3
 * modified: sharedobj/src/ObjectSpace_T_v2.m3
 * modified: sharedobj/src/SharedObj.i3
 * modified: sharedobj/src/SharedObjError.i3
 * modified: sharedobj/src/SharedObjF.i3
 * modified: sharedobj/src/SharedObjF.m3
 * modified: sharedobj/src/SharedObjRT.i3
 * modified: sharedobj/src/SharedObjRT.m3
 * modified: sharedobj/src/SharedObjRTF.i3
 * modified: sharedobj/src/SharedObjRep.i3
 * modified: sharedobj/src/SharedObjRep.m3
 * modified: sharedobj/src/SharedObjStubLib.i3
 * modified: sharedobj/src/SharedObjStubLib.m3
 * modified: sharedobj/src/SpaceConn.i3
 * modified: sharedobj/src/SpaceConn.m3
 * modified: sharedobj/src/WeakerRef.i3
 * modified: sharedobj/src/WeakerRef.m3
 * modified: sharedobj/src/m3makefile
 * modified: sharedobj/src/m3overrides
 * modified: sharedobj/tests/netobjtest/src/m3makefile
 * modified: sharedobj/tests/obsequence/src/m3makefile
 * modified: sharedobj/tests/tracker/src/m3makefile
 *
 * Revision 1.1.1.1  2001/12/02 13:14:14  wagner
 * Blair MacIntyre's sharedobj package
 *
 * Revision 1.2  1996/11/22 19:00:38  bm
 * fixed header
 *
 * 
 * HISTORY
 

INTERFACE ObjectInfo;

IMPORT SharedObj, ObjCopy, SharedObjRep, ObjCopyList, WeakRef,
       EventConnList, Thread, SpaceConn, EventNumber;

CONST Brand = "Shared Object Info";

TYPE
  T  = Thread.Mutex OBJECT
             (* The wire representation of the object. *)
             wrep  : SharedObjRep.WireRep;

             (* Used by all hosts. *)
             seqNo     : SharedObj.SequenceNumber;
             conns     : EventConnList.T            := NIL;

             (* Used by hosts that have a copy of the object. *)
             isStandalone: BITS 1 FOR BOOLEAN := TRUE;
             isOwner     : BITS 1 FOR BOOLEAN := FALSE;
             isLocker    : BITS 1 FOR BOOLEAN := FALSE;
             hasCopy     : BITS 1 FOR BOOLEAN := FALSE;
             obj         : WeakRef.T;

             (* Used by the sequencers. *)
             lock      : ObjCopy.T                  := NIL;
             owner     : ObjCopy.T                  := NIL;
             sequencer : SpaceConn.T                := NIL;
             clients   : ObjCopyList.T              := NIL;

             (* Different meaning on sequencers. *)
             fastClients: ObjCopyList.T             := NIL;

             (* threads that sent messages to be sequenced *)
             waiting: REF ARRAY OF Blocked := NIL;
           METHODS
             init (seqNo: SharedObj.SequenceNumber := NIL): T := Init;
             pickThreadSlot(): CARDINAL := PickThreadSlot;
             releaseThreadSlot(id: CARDINAL) := ReleaseThreadSlot;
          END;

TYPE
  Blocked = RECORD
    used: BOOLEAN;
    en: EventNumber.T := NIL;
    cv: Thread.Condition;
  END;
The information maintained by the runtime system for each shared object it knows about. The seqNo is the highest sequence number seen in, or assigned to, any update event. If this host is forwarding to any other host, either because its a sequencer or because it is doing fast updates, conns contains the list of Conn.Ts to use as a parameter to EventPort.T.mcast().

If there is a copy of the object on this host, obj is a weak reference to the object itself. The following flags define the state of this copy of the object: isStandalone indicates if the object exists on any other machines or just this one, isOwner indicates if this machine owns the objects and isLocker is true if someone has locked the object through this copy.

If the host is the sequencer for this group, it can also have the following additional fields set. lock is the the copy that is locking the object and owner is the copy that owns the object, if either of those conditions are true. If some other sequencer is doing the sequencing for this object, sequencer refers to it. clients is a list of clients.

fastClients is the list of clients that are getting timely updates. On a sequencer, this is the list that has been delegated to the owner. Thus, conns corresponds to clients-fastClients. On the owner, this is the list we are sending to. In this case, conns corresponds to fastClients.

PROCEDURE Init(self: T; seqNo: SharedObj.SequenceNumber): T;
PROCEDURE PickThreadSlot(self: T) : CARDINAL;
PROCEDURE ReleaseThreadSlot(self: T; id: CARDINAL);
Generate a text version for debugging.
PROCEDURE ToText(objInfo: T): TEXT;

END ObjectInfo.