Copyright (C) 1994, Digital Equipment Corp.
INTERFACE ObValue;
IMPORT SynWr, SynLocation, Rd, Wr, ObTree, NetObj, Thread, AtomList;
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. *)
picklable: BOOLEAN;
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, NetObj.Error} := 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;
ValObj =
Val BRANDED "ValObj" OBJECT
remote: RemObj;
END;
ObjFields =
ARRAY OF RECORD
label: TEXT;
field: Val;
(* ValMeth for method fields,
ValAlias for alias fields,
other Val for value fields *)
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};
Set(val: Val) RAISES {NetObj.Error};
END;
RemVarServer <:
RemVar;
RemArray =
NetObj.T BRANDED "RemArray" OBJECT
METHODS
Size(): INTEGER
RAISES {NetObj.Error};
Get(i: INTEGER): Val
RAISES {ServerError, NetObj.Error};
Set(i: INTEGER; val: Val)
RAISES {ServerError, NetObj.Error};
Sub(start,size: INTEGER): ValArray
RAISES {ServerError, NetObj.Error};
(* Extract the subarray self[start for size]. *)
Upd(start, size: INTEGER; READONLY other: REF Vals)
RAISES {ServerError, NetObj.Error};
(* Update self[start for size] with other[0 for size]. *)
Obtain(): REF Vals RAISES {NetObj.Error};
(* 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};
Select(label: TEXT; internal: BOOLEAN; VAR hint: INTEGER): Val
RAISES {Error, Exception, ServerError, NetObj.Error};
Invoke(label: TEXT; argNo: INTEGER; READONLY args: Vals;
internal: BOOLEAN; VAR hint: INTEGER): Val
RAISES {Error, Exception, ServerError, NetObj.Error};
Update(label: TEXT; val: Val; internal: BOOLEAN;
VAR hint: INTEGER) RAISES {ServerError, NetObj.Error};
Redirect(val: Val; internal: BOOLEAN)
RAISES {ServerError, NetObj.Error};
Has(label: TEXT; VAR hint: INTEGER): BOOLEAN RAISES {NetObj.Error};
(* Whether a field called label exists. *)
Obtain(internal: BOOLEAN): REF ObjFields
RAISES {ServerError, NetObj.Error};
(* 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.
*)
Sync =
BRANDED "Sync" OBJECT
mutex: Thread.Mutex;
END;
RemEngine =
NetObj.T BRANDED "RemEngine" OBJECT
METHODS
Who(): TEXT RAISES {NetObj.Error};
Eval(proc: Val; mySelf: RemObj): Val
RAISES {Error, Exception, ServerError, NetObj.Error};
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};
OpenWrite(fileName: TEXT): Wr.T RAISES {NetObj.Error, ServerError};
OpenAppend(fileName: TEXT): Wr.T RAISES {NetObj.Error, ServerError};
END;
RemFileSystemServer <: RemFileSystem;
ArgArray = ARRAY [1..8] OF Val;
VAR
valOk: Val;
netException, threadAlerted: 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 ObjClone1(remObj: RemObj; mySelf: RemObj): ValObj
RAISES {ServerError, NetObj.Error};
(* mySelf is the object invoking cloning, if any, or NIL.
Then cloning is self-inflicted if remObj=mySelf. *)
PROCEDURE ObjClone(READONLY remObjs: ARRAY OF RemObj;
mySelf: RemObj): ValObj
RAISES {ServerError, NetObj.Error};
(* mySelf is the object invoking cloning, if any, or NIL.
Then cloning is self-inflicted for any remObjs[i]=mySelf. *)
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: RemObj): 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 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 CopyVal(val: Val; tbl: Tbl; loc: SynLocation.T): Val
RAISES {Error, NetObj.Error};
(* 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, NetObj.Error};
PROCEDURE CopyLocalToVal(val: Val; tbl: Tbl; loc: SynLocation.T)
: Val RAISES {Error, NetObj.Error};
(* 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.