Copyright 1991 Digital Equipment Corporation. Distributed only by permission.
<*PRAGMA SHARED *> INTERFACEObValue ; IMPORT SynWr, SynLocation, Rd, Wr, ObTree, NetObj, Thread, AtomList; IMPORT SharedObj; EXCEPTION Exception(ExceptionPacket); (* trappable *) Error(ErrorPacket); (* only trappable by try-else *) ServerError(TEXT); (* like Error, but has no location info; immediately converted to Error on the way back from a server *) TYPE ErrorPacket = BRANDED "ErrorPacket" OBJECT msg: TEXT; location: SynLocation.T; END; ExceptionPacket = BRANDED "ExceptionPacket" OBJECT msg: TEXT; location: SynLocation.T; exception: ValException; data: Val; END; Tbl <: REFANY; TYPE Vals = ARRAY OF Val; Env = BRANDED OBJECT name: ObTree.IdeName; rest: Env; END; LocalEnv = Env BRANDED OBJECT val: Val; END; GlobalEnv = REF Vals; Val = BRANDED "Val" OBJECT END; ValOk = Val BRANDED "ValOk" OBJECT END; ValBool = Val BRANDED "ValBool" OBJECT bool: BOOLEAN; END; ValChar = Val BRANDED "ValChar" OBJECT char: CHAR; END; ValText = Val BRANDED "ValText" OBJECT text: TEXT; (* Non-NIL ! *) END; ValInt = Val BRANDED "ValInt" OBJECT int: INTEGER; temp: BOOLEAN:=FALSE; END; ValReal = Val BRANDED "ValReal" OBJECT real: LONGREAL; temp: BOOLEAN:=FALSE; END; ValException = Val BRANDED "ValException" OBJECT name: TEXT; END; ValOption = Val BRANDED "ValOption" OBJECT tag: TEXT; val: Val; END; ValVar = Val BRANDED "ValVar" OBJECT remote: RemVar; END; ValArray = Val BRANDED "ValArray" OBJECT remote: RemArray; END; ValFun = Val BRANDED "ValFun" OBJECT fun: ObTree.TermFun; global: GlobalEnv; END; ValMeth = Val BRANDED "ValMeth" OBJECT meth: ObTree.TermMeth; global: GlobalEnv; END; ValAlias = Val BRANDED "ValAlias" OBJECT label: TEXT; labelIndexHint: INTEGER; obj: ValObj; END; ValAnything = (* to be subtyped *) Val BRANDED "ValAnything" OBJECT what: TEXT; (* Only used for printing. *) tag: TEXT := NIL; (* Used to identify the type with reflection *) picklable: BOOLEAN := TRUE; METHODS Is(other: ValAnything): BOOLEAN := IsSelfOther; (* Override with what you want the "is" primitive to do to determine equality of two ValAnything values. The default method returns self=other. *) Print(): TEXT := PrintWhat; (* Override with a routine to print this value. The default method returns the "what"field. *) Copy(tbl: Tbl; loc: SynLocation.T): ValAnything RAISES {Error, SharedObj.Error, NetObj.Error, Thread.Alerted} := CopyError; (* Override with a routine that makes a copy of this value (the default CopyError raises error, CopyId returns self). Use this pattern: IF tbl.Get(self, (*out*)newVal) THEN RETURN newVal END; newVal := NEW(ValAnything, what:=self.what, ... all private fields set to NIL ... ); EVAL tbl.Put(self, newVal); ... fill private fields, possibly calling: newVal.field:=ObValue.CopyVal(self.field, tbl, loc) ... RETURN newVal; *) END; (* There are 3 kinds of objects, Remote (Network Objects), Replicated (Shared Objects) and Simple (normal Modula-3 Objects). The Obliq wrappers contain a reference to the real data objects in an appropriately typed data field. These are ValObj wrapper methods allow each subtype to redirect the method calls to their approriate data object (RemObj, ReplObj or SimpleObj). *) ValObj = Val BRANDED "ValObj" OBJECT METHODS Who(VAR(*out*) protected, serialized: BOOLEAN): TEXT RAISES {NetObj.Error, SharedObj.Error, Thread.Alerted}; Select(label: TEXT; internal: BOOLEAN; VAR hint: INTEGER): Val RAISES {Error, Exception, ServerError, SharedObj.Error, NetObj.Error, Thread.Alerted}; Invoke(label: TEXT; argNo: INTEGER; READONLY args: Vals; internal: BOOLEAN; VAR hint: INTEGER): Val RAISES {Error, Exception, ServerError, SharedObj.Error, NetObj.Error, Thread.Alerted}; Update(label: TEXT; val: Val; internal: BOOLEAN; VAR hint: INTEGER) RAISES {ServerError, SharedObj.Error, NetObj.Error, Thread.Alerted}; Redirect(val: Val; internal: BOOLEAN) RAISES {ServerError, SharedObj.Error, NetObj.Error, Thread.Alerted}; Has(label: TEXT; VAR hint: INTEGER): BOOLEAN RAISES {NetObj.Error, Thread.Alerted, SharedObj.Error}; Obtain(internal: BOOLEAN): REF ObjFields RAISES {ServerError, SharedObj.Error, NetObj.Error, Thread.Alerted}; END; ValRemObj <: ValRemObjPublic; ValRemObjPublic = ValObj OBJECT remote: RemObj; END; ValReplObj <: ValReplObjPublic; ValReplObjPublic = ValObj OBJECT replica: ReplObj; END; ValSimpleObj <: ValSimpleObjPublic; ValSimpleObjPublic = ValObj OBJECT simple: SimpleObj; END; ObjFields = ARRAY OF Field; Field = RECORD label: TEXT; field: Val; (* ValMeth for method fields, ValAlias for alias fields, other Val for value fields *) update: BOOLEAN := FALSE; (* TRUE for replicated object update method, FALSE otherwise *) END; ValEngine = Val BRANDED "ValEngine" OBJECT remote: RemEngine; END; ValFileSystem = ValAnything BRANDED "ValFileSystem" OBJECT remote: RemFileSystem; OVERRIDES Is := FileSystemIs; Copy := CopyId; END; ValProcessor = ValAnything BRANDED "ValProcessor" OBJECT OVERRIDES Copy := CopyId; END; RemVar = NetObj.T BRANDED "RemVar" OBJECT METHODS Get(): Val RAISES {NetObj.Error, Thread.Alerted}; Set(val: Val) RAISES {NetObj.Error, Thread.Alerted}; END; RemVarServer <: RemVar; RemArray = NetObj.T BRANDED "RemArray" OBJECT METHODS Size(): INTEGER RAISES {NetObj.Error, Thread.Alerted}; Get(i: INTEGER): Val RAISES {ServerError, NetObj.Error, Thread.Alerted}; Set(i: INTEGER; val: Val) RAISES {ServerError, NetObj.Error, Thread.Alerted}; Sub(start,size: INTEGER): ValArray RAISES {ServerError, NetObj.Error, Thread.Alerted}; (* Extract the subarray self[start for size]. *) Upd(start, size: INTEGER; READONLY other: REF Vals) RAISES {ServerError, NetObj.Error, Thread.Alerted}; (* Update self[start for size] with other[0 for size]. *) Obtain(): REF Vals RAISES {NetObj.Error, Thread.Alerted}; (* Return self.array if local, or a copy of it if remote. Modifying the result of Obtain may violate network transparency. *) END; RemArrayServer <: RemArray; RemObj = NetObj.T BRANDED "RemObj" OBJECT METHODS Who(VAR(*out*) protected, serialized: BOOLEAN): TEXT RAISES {NetObj.Error, Thread.Alerted}; Select(label: TEXT; internal: BOOLEAN; VAR hint: INTEGER): Val RAISES {Error, Exception, ServerError, SharedObj.Error, NetObj.Error, Thread.Alerted}; Invoke(label: TEXT; argNo: INTEGER; READONLY args: Vals; internal: BOOLEAN; VAR hint: INTEGER): Val RAISES {Error, Exception, ServerError, SharedObj.Error, NetObj.Error, Thread.Alerted}; Update(label: TEXT; val: Val; internal: BOOLEAN; VAR hint: INTEGER) RAISES {ServerError, SharedObj.Error, NetObj.Error, Thread.Alerted}; Redirect(val: Val; internal: BOOLEAN) RAISES {ServerError, SharedObj.Error, NetObj.Error, Thread.Alerted}; Has(label: TEXT; VAR hint: INTEGER): BOOLEAN RAISES {NetObj.Error, Thread.Alerted}; (* Whether a field called label exists. *) Obtain(internal: BOOLEAN): REF ObjFields RAISES {ServerError, NetObj.Error, Thread.Alerted}; (* Return self.fields if local, or a copy of it if remote. Modifying the result of Obtain may violate network transparency. *) END; RemObjServer <: RemObjServerPublic; RemObjServerPublic = RemObj BRANDED "RemObjServerPublic" OBJECT who: TEXT; sync: Sync; END; (* RemObjServer, a subtype of RemObj, is the standard implementation of local objects. Another subtype of RemObj is automatically produced by the Network Objects stub generator, for remote surrogates. Further subtypes of RemObj can be defined and used as client-specific pseudo-objects. In the latter case, the result of Who is used for printing; copying, cloning, and pickling operate on the results of Who and Obtain. *) NonRemObjHookServer <: NonRemObjHook; NonRemObjHook = NetObj.T BRANDED "NonRemObjHook" OBJECT METHODS init(remObj: ValObj): NonRemObjHook RAISES {NetObj.Error, Thread.Alerted}; Get(): ValObj RAISES {NetObj.Error, Thread.Alerted}; END; (* NonRemObjHook is used by the obliq net_import and net_export commands to allow replicated and simple objects to be exported and imported. *) ReplObjStd <: ReplObj; <* SHARED UPDATE METHODS ReplObjStd.init, ReplObjStd.InvokeUpdate, ReplObjStd.Update *> ReplObj <: ReplObjPublic; ReplObjPublic = SharedObj.T BRANDED "ReplObjServerPublic" OBJECT METHODS init (): ReplObj RAISES {SharedObj.Error}; Who(VAR(*out*) protected: BOOLEAN): TEXT RAISES {SharedObj.Error}; (* All replicated objects are protected and serialized! *) Select(label: TEXT; VAR hint: INTEGER): Val RAISES {Error, Exception, ServerError, SharedObj.Error}; Invoke(label: TEXT; argNo: INTEGER; READONLY args: Vals; VAR hint: INTEGER): Val RAISES {Error, Exception, ServerError, SharedObj.Error}; Update(label: TEXT; val: Val; internal: BOOLEAN; VAR hint: INTEGER) RAISES {ServerError, SharedObj.Error}; Has(label: TEXT; VAR hint: INTEGER): BOOLEAN RAISES {SharedObj.Error}; (* Whether a field called label exists. *) Obtain(internal: BOOLEAN): REF ObjFields RAISES {ServerError, SharedObj.Error}; (* Return self.fields. Modifying the result of Obtain may violate network transparency. *) END; (* ReplObj is the implementation of replicated objects. The default internal implementation is ReplObjStd. Further subtypes of ReplObj can be defined and used as client-specific pseudo-objects. *) SimpleObj <: SimpleObjPublic; SimpleObjPublic = BRANDED "SimpleObjPublic" OBJECT who: TEXT; sync: Sync; METHODS Who(VAR(*out*) protected, serialized: BOOLEAN): TEXT; Select(label: TEXT; internal: BOOLEAN; VAR hint: INTEGER): Val RAISES {Error, Exception, ServerError, SharedObj.Error, NetObj.Error, Thread.Alerted}; Invoke(label: TEXT; argNo: INTEGER; READONLY args: Vals; internal: BOOLEAN; VAR hint: INTEGER): Val RAISES {Error, Exception, ServerError, SharedObj.Error, NetObj.Error, Thread.Alerted}; Update(label: TEXT; val: Val; internal: BOOLEAN; VAR hint: INTEGER) RAISES {ServerError, SharedObj.Error, NetObj.Error, Thread.Alerted}; Redirect(val: Val; internal: BOOLEAN) RAISES {ServerError, SharedObj.Error, NetObj.Error, Thread.Alerted}; Has(label: TEXT; VAR hint: INTEGER): BOOLEAN; (* Whether a field called label exists. *) Obtain(internal: BOOLEAN): REF ObjFields RAISES {ServerError}; (* Return self.fields if local, or a copy of it if remote. Modifying the result of Obtain may violate network transparency. *) END; Sync = BRANDED "Sync" OBJECT mutex: Thread.Mutex; END; RemEngine = NetObj.T BRANDED "RemEngine" OBJECT METHODS Who(): TEXT RAISES {NetObj.Error, Thread.Alerted}; Eval(proc: Val; mySelf: ValObj): Val RAISES {Error, Exception, ServerError, NetObj.Error, Thread.Alerted}; END; RemEngineServer = RemEngine BRANDED "RemEngineServer" OBJECT who: TEXT; arg: Val; OVERRIDES Who := EngineWho; Eval := EngineEval; END; RemFileSystem = NetObj.T BRANDED "RemFileSystem" OBJECT METHODS OpenRead(fileName: TEXT): Rd.T RAISES {NetObj.Error, ServerError, Thread.Alerted}; OpenWrite(fileName: TEXT): Wr.T RAISES {NetObj.Error, ServerError, Thread.Alerted}; OpenAppend(fileName: TEXT): Wr.T RAISES {NetObj.Error, ServerError, Thread.Alerted}; END; RemFileSystemServer <: RemFileSystem; ArgArray = ARRAY [1..8] OF Val; VAR valOk: Val; netException, threadAlerted, sharedException, sharedFatal: ValException; showNetObjMsgs: BOOLEAN; machineAddress: TEXT; localProcessor: ValProcessor; PROCEDURE Setup(); (* To be called before any other use of this module. *) PROCEDURE Is(v1,v2: Val; location: SynLocation.T): BOOLEAN; PROCEDURE NewText(text: TEXT): Val; (* Create an Obliq text containing a non-NIL m3 TEXT. *) PROCEDURE NewVar(val: Val): ValVar; (* Create a new variable. *) PROCEDURE NewArray(READONLY vals: Vals): ValArray; (* Create a new array. *) PROCEDURE NewArrayFromVals(vals: REF Vals): ValArray; (* Careful: the vals passed in are shared and may get modified later. *) PROCEDURE ArrayCat(vals1, vals2: REF Vals): Val RAISES {}; PROCEDURE NewObject(READONLY fields: ObjFields; who: TEXT:=""; protected: BOOLEAN:=FALSE; sync: Sync:=NIL): ValObj; (* Create a new object. *) PROCEDURE NewObjectFromFields(fields: REF ObjFields; who: TEXT; protected: BOOLEAN; sync: Sync): ValObj; (* Careful: the fields passed in are shared and may get modified later. *) PROCEDURE NewReplObject(READONLY fields: ObjFields; who: TEXT:=""; protected: BOOLEAN:=FALSE): ValObj RAISES {SharedObj.Error}; (* Create a new replicated object. *) PROCEDURE NewReplObjectFromFields(fields: REF ObjFields; who: TEXT; protected: BOOLEAN): ValObj RAISES {SharedObj.Error}; (* Careful: the fields passed in are shared and may get modified later. *) PROCEDURE NewSimpleObject(READONLY fields: ObjFields; who: TEXT:=""; protected: BOOLEAN:=FALSE; sync: Sync:=NIL): ValObj; (* Create a new simple object. *) PROCEDURE NewSimpleObjectFromFields(fields: REF ObjFields; who: TEXT; protected: BOOLEAN; sync: Sync): ValObj; (* Careful: the fields passed in are shared and may get modified later. *) PROCEDURE ToSimpleObj(READONLY obj: ValObj; mySelf: ValObj): ValObj RAISES {ServerError, NetObj.Error, SharedObj.Error, Thread.Alerted}; (* Create a SimpleObj from another ValObj. *) PROCEDURE ToReplObj(READONLY obj: ValObj; mySelf: ValObj; READONLY updateMethods: ARRAY OF TEXT): ValObj RAISES {ServerError, NetObj.Error, SharedObj.Error, Thread.Alerted}; (* Create a ReplObj from another ValObj. *) PROCEDURE ToRemObj(READONLY obj: ValObj; mySelf: ValObj): ValObj RAISES {ServerError, NetObj.Error, SharedObj.Error, Thread.Alerted}; (* Create a RemObj from another ValObj. *) PROCEDURE SetObjPickler(obj: ValObj; picklerIn: ValSimpleObj; picklerOut: ValSimpleObj; mySelf: ValObj) RAISES {ServerError, NetObj.Error, SharedObj.Error, Thread.Alerted}; (* mySelf is the object invoking the pickler setting. set the pickler objects "picklerIn" and "picklerOut" for an object "obj." These objects are valid iff they have the set of fields corresponding to {obj's fields - obj's method fields} (ie. all of obj's non-method fields.) *) PROCEDURE ObjClone1(remObj: ValObj; mySelf: ValObj): ValObj RAISES {ServerError, NetObj.Error, SharedObj.Error, Thread.Alerted}; (* mySelf is the object invoking cloning, if any, or NIL. Then cloning is self-inflicted if Is(remObj, mySelf) *) PROCEDURE ObjClone(READONLY valObjs: ARRAY OF ValObj; mySelf: ValObj): ValObj RAISES {ServerError, NetObj.Error, SharedObj.Error, Thread.Alerted}; (* mySelf is the object invoking cloning, if any, or NIL. Then cloning is self-inflicted if for any Is(remObjs[i],mySelf). *) PROCEDURE ObjNotify(val: Val; notifyProc: ValFun); (* Create a NetObjNotifier on val if it is a remote data value. When val becomes inaccesible, notifyProc is called. notifyProc should take two arguments, the value and a text string which will contain "Dead" or "Failed". See NetObjNotifier.i3 for details. *) PROCEDURE NewAlias(obj: ValObj; label: TEXT; location: SynLocation.T) : ValAlias RAISES {Error, Exception}; PROCEDURE EngineWho(self: RemEngineServer): TEXT RAISES {NetObj.Error}; PROCEDURE EngineEval(self: RemEngineServer; proc: Val; mySelf: ValObj): Val RAISES {Error, Exception, ServerError, NetObj.Error}; PROCEDURE NewFileSystem(readOnly: BOOLEAN): ValFileSystem; PROCEDURE FileSystemIs(self: ValFileSystem; other: ValAnything): BOOLEAN; PROCEDURE SameException(exc1, exc2: ValException): BOOLEAN; PROCEDURE RaiseError(msg: TEXT; location: SynLocation.T) RAISES {Error}; PROCEDURE RaiseException(exception: ValException; msg: TEXT; loc: SynLocation.T) RAISES {Exception}; PROCEDURE RaiseNetException(msg: TEXT; atoms: AtomList.T; loc: SynLocation.T) RAISES {Exception}; PROCEDURE RaiseSharedException(msg: TEXT; atoms: AtomList.T; loc: SynLocation.T) RAISES {Exception}; PROCEDURE ErrorMsg(swr: SynWr.T; packet: ErrorPacket); PROCEDURE ExceptionMsg(wr: SynWr.T; packet: ExceptionPacket); PROCEDURE BadOp(pkg, op: TEXT; location: SynLocation.T) RAISES {Error}; PROCEDURE BadArgType(argNo: INTEGER; expected, pkg, op: TEXT; location: SynLocation.T) RAISES {Error}; PROCEDURE BadArgVal(argNo: INTEGER; expected, pkg, op: TEXT; location: SynLocation.T) RAISES {Error}; PROCEDURE BadArgsNoMsg(desired, found: INTEGER; routineKind, routineName: TEXT): TEXT; PROCEDURE IsSelfOther(self, other: ValAnything): BOOLEAN; PROCEDURE PrintWhat(self: ValAnything): TEXT; PROCEDURE CopyError(self: ValAnything; tbl: Tbl; loc: SynLocation.T): ValAnything RAISES {Error}; PROCEDURE CopyId(self: ValAnything; tbl: Tbl; loc: SynLocation.T): ValAnything; PROCEDURE InhibitTransmission(tc: INTEGER; reason: TEXT); (* Inhibits the network transmission of any object whose type has typecode "tc"; an obliq exception will result. To be used on all M3 types that are embedded in obliq values but that have only "local" meaning, such as threads. The reason should be a string like "threads cannot be transmitted/duplicated". *) PROCEDURE NewTbl(): Tbl; (* A new empty table for CopyVal. *) PROCEDURE TblGet (self: Tbl; old: REFANY; VAR (*out*) new: REFANY): BOOLEAN; PROCEDURE TblPut (self: Tbl; old, new: REFANY); PROCEDURE CopyVal(val: Val; tbl: Tbl; loc: SynLocation.T): Val RAISES {Error, SharedObj.Error, NetObj.Error, Thread.Alerted}; (* Make a complete local copy of val, preserving sharing and circularities. Substructures are fetched over the network, if necessary. Protected objects and non-transferrable values produce errors. *) PROCEDURE CopyValToLocal(val: Val; tbl: Tbl; loc: SynLocation.T) : Val RAISES {Error, SharedObj.Error, NetObj.Error, Thread.Alerted}; PROCEDURE CopyLocalToVal(val: Val; tbl: Tbl; loc: SynLocation.T) : Val RAISES {Error, SharedObj.Error, NetObj.Error, Thread.Alerted}; (* Internal use only. *) VAR sysCallFailure: ValException; TYPE SysCallClosure = OBJECT METHODS SysCall(READONLY args: Vals; loc: SynLocation.T:=NIL): Val RAISES{Error, Exception}; (* To be overridden. It should return an obliq Val, or raise an error by calling RaiseError, or raise an exception by calling RaiseException. The raised exception should normally be sysCallFailure. The loc parameter should be passed through whenever appropriate, or appriate error locations should be synthesized. Alternatively, errors and exceptions may be left uncought, so that they propagate back to Obliq; however this may result in poor error location reporting. *) END; PROCEDURE RegisterSysCall(name: TEXT; clos: SysCallClosure); (* To register a Modula-3 procedure that can be called from Obliq, under a given name. Re-registering for the same name overrides the previous proc for that name. Use clos=NIL to unregister. *) PROCEDURE FetchSysCall(name: TEXT; VAR(*out*) clos: SysCallClosure): BOOLEAN; (* To fetch a registered Modula-3 procedure by its given name. Returns FALSE if not found. *) END ObValue.