
DIRECTORY
BridgeExec,
Process,
RefTab,
Rope,
SymTab
;

BridgeExecImpl: CEDAR MONITOR
LOCKS session USING session: Session
IMPORTS Process, RefTab, SymTab
EXPORTS BridgeExec
~ {

CreateProc: TYPE ~ BridgeExec.CreateProc;
DestroyProc: TYPE ~ BridgeExec.DestroyProc;
Instance: TYPE ~ BridgeExec.Instance;
NetworkStreamPair: TYPE ~ BridgeExec.NetworkStreamPair;
ROPE: TYPE ~ Rope.ROPE;
Registration: TYPE ~ REF RegistrationObject;
RegistrationObject: TYPE ~ RECORD [
name: ROPE,
createProc: CreateProc,
clientData: REF,
destroyProc: DestroyProc
];

registrationTab: SymTab.Ref м SymTab.Create[];

Register: PUBLIC PROC [name: ROPE, createProc: CreateProc, clientData: REF, destroyProc: DestroyProc] ~ {
IF createProc = NIL
THEN {
[] м SymTab.Delete[x~registrationTab, key~name] }
ELSE {
r: Registration м NEW[RegistrationObject м [name, createProc, clientData, destroyProc]];
[] м SymTab.Store[x~registrationTab, key~name, val~r] };
};

GetRegistration: PROC [name: ROPE] RETURNS [registration: Registration] ~ {
val: REF;
[val~val] м SymTab.Fetch[x~registrationTab, key~name];
registration м NARROW[val];
};
Session: TYPE ~ REF SessionObject;
SessionObject: PUBLIC TYPE ~ MONITORED RECORD [
name: ROPE,
locks: NAT м 0,
unlocked: CONDITION,
dead: BOOL м FALSE,
creationTab: RefTab.Ref
];

CreateSession: PUBLIC PROC [sessionName: ROPE] RETURNS [newSession: Session] ~ {
newSession м NEW[SessionObject м [name~sessionName, creationTab~RefTab.Create[]]];
};

DestroySession: PUBLIC PROC [session: Session] ~ {
TRUSTED {
Process.Detach[ FORK DestroySessionWorker[session] ] };
};

DestroySessionWorker: PROC [session: Session] ~ {
DestroyOne: RefTab.EachPairAction -- [key, val] RETURNS [quit] -- ~ {
DestroyInstance[session, NARROW[key]];
RETURN [FALSE] };
KillSessionWhenUnlocked[session];
[] м RefTab.Pairs[x~session.creationTab, action~DestroyOne];
};

KillSessionWhenUnlocked: ENTRY PROC [session: Session] ~ {
ENABLE UNWIND => NULL;
WHILE session.locks > 0 DO WAIT session.unlocked ENDLOOP;
session.dead м TRUE;
};

LockSession: ENTRY PROC [session: Session]
RETURNS [ok: BOOL] ~ {
ENABLE UNWIND => NULL;
IF session.dead
THEN RETURN [FALSE]
ELSE { session.locks м session.locks.SUCC; RETURN [TRUE] };
};

UnlockSession: ENTRY PROC [session: Session] ~ {
ENABLE UNWIND => NULL;
IF (session.locks м session.locks.PRED) = 0 THEN
BROADCAST session.unlocked;
};

SessionNameFromSession: PUBLIC PROC [session: Session]
RETURNS [sessionName: ROPE] ~ { RETURN [session.name] };


SessionIsDead: PUBLIC ENTRY PROC [session: Session]
RETURNS [dead: BOOL] ~ {
ENABLE UNWIND => NULL;
RETURN [session.dead] };
Creation: TYPE ~ REF CreationObject;
CreationObject: TYPE ~ RECORD [
registration: Registration,
args: ROPE,
nsp: NetworkStreamPair,
close: PROC[nsp: NetworkStreamPair],
instance: Instance
];

CreateInstance: PUBLIC PROC [cmdName: ROPE, nsp: NetworkStreamPair, args: ROPE, session: Session, close: PROC[nsp: NetworkStreamPair]] RETURNS [instance: Instance м NIL] ~ {
registration: Registration;
creation: Creation;
registration м GetRegistration[cmdName];
IF registration = NIL THEN RETURN;
IF registration.createProc = NIL THEN RETURN;
IF NOT LockSession[session] THEN RETURN;
instance м registration.createProc[nsp, args, session, registration.clientData];
IF instance = NIL THEN { UnlockSession[session]; RETURN };
creation м NEW[CreationObject м [registration, args, nsp, close, instance]];
[] м RefTab.Store[x~session.creationTab, key~instance, val~creation];
UnlockSession[session];
};

DestroyInstance: PUBLIC PROC [session: Session, instance: Instance, clientData: REF м NIL] ~ {
creation: Creation м DeleteCreationFromSession[session, instance];
IF creation # NIL THEN TRUSTED {
Process.Detach[ FORK DestroyInstanceInner[creation, instance, clientData] ];
};
};

DestroyInstanceInner: PROC [creation: Creation, instance: Instance, clientData: REF] ~ {
creation.registration.destroyProc[instance, clientData];
IF creation.close#NIL THEN creation.close[creation.nsp];
creation.instance м NIL; -- help break cycles for garbage collector
};

DeleteCreationFromSession: ENTRY PROC [session: Session, instance: Instance]
RETURNS [creation: Creation] ~ {
ENABLE UNWIND => NULL;
val: REF;
[val~val] м RefTab.Fetch[x~session.creationTab, key~instance];
[] м RefTab.Delete[x~session.creationTab, key~instance];
creation м NARROW[val];
};
}...
     
BridgeExecImpl.mesa
Copyright ╙ 1992 by Xerox Corporation.  All rights reserved.
Demers, May 11, 1990 5:10 pm PDT
Christian Le Cocq September 30, 1987 4:52:13 pm PDT
Eduardo Pelegri-Llopart April 5, 1989 6:05:12 am PDT
Command Registration
Session Management
Instance Management
Э╩#  ХNewlineDelimiter
Ц(cedarcode) styleЩ codeЩKЪЬ
╧eЬ1Щ<KЩ KЩ3KЩ4KШ ЧЪ╧k	Ш	KЪЬШKЪЬШKЪЬШKЪЬШKЪЬШKШKШ ЧЪ╧nЬЮЬЮШKЪЮЬ	ЮЬШ$KЪЮЬШKЪЮЬШKЪЬШKШ KЪЬЮЬШ)KЪЬЮЬШ+KЪЬ
ЮЬШ%KЪЬЮЬ Ш7KЪЮЬЮЬЮЬШheadЩKЪЬЮЬЮЬШ,ЪЬЮЬЮЬШ#KЪЬЮЬШKШKЪЬЮЬШKЪЬШKШKШ ЧKШ.KШ Ъ
ЯЬЮЬЮЬЮЬ&ЮЬШiЪЮЬЮШЪЮЬШKШ1ЧЪЮЬШKЪЬЮЬCШXKШ8ЧЧKШKШ ЧЪЯЬЮЬЮЬЮЬ!ШKKЪЬЮЬШ	KШ6KЪЬЮЬШKШЧЧЩKЪЬ	ЮЬЮЬШ"ЪЬЮЬЮЬЮЬШ/KЪЬЮЬШKЪЬЮЬШKЪЬ
Ю	ЬШKЪЬЮЬЮЬШKШKШЧKШ Ъ
ЯЬЮЬЮЬЮЬЮЬШPKЪЬЮЬBШRKШKШ ЧЪЯЬЮЬЮЬШ2ЪЮЬШ	KЪЬЮЬ#Ш7ЧKЪЬШKШ ЧЪЯЬЮЬШ1ЪЯ
Ь╧cЬШEKЪЬЮЬШ&KЪЮЬЮЬШЧKЪЬ!Ш!KШ<KЪЬШKШ ЧЪЯЬЮЬЮЬШ:KЪЮЬЮЬЮЬШKЪЮЬЮЬЮЬЮЬШ9KЪЬЮЬШKЪЬШKШ ЧЪ
ЯЬЮЬЮЬЮЬЮЬШAKЪЮЬЮЬЮЬШЪЮЬШKЪЮЬЮЬЮЬШKЪЮЬ!ЮЬЮЬЮЬШ;ЧKЪЬШKШ ЧЪЯЬЮЬЮЬШ0KЪЮЬЮЬЮЬШKЪЮЬ ЮЬЮЬЮ	ЬШLKЪЬШKШ ЧKЪЯЬЮЬЮЬЮЬЮЬЮЬШoKШ KШ ЪЯЬЮЬЮЬЮЬЮЬЮЬШLKЪЮЬЮЬЮЬШKЪЮЬШЧЧЩKЪЬ
ЮЬЮЬШ$ЪЬЮЬЮЬШKШKЪЬЮЬШKЪЬШKЪЬЮЬШ$KШKШKШ ЧЪЯЬЮЬЮЬЮЬ ЮЬЮЬЮЬЮЬШнKШKШKШ(KЪЮЬЮЬЮЬЮЬШ"KЪЮЬЮЬЮЬЮЬШ-KЪЮЬЮЬЮЬЮЬШ(KШPKЪЮЬЮЬЮЬЮЬШ:KЪЬЮЬ>ШLKШEKЪЬШKШKШ ЧЪ
ЯЬЮЬЮЬ4ЮЬЮЬШ^KШBЪЮЬЮЬЮЬЮЬШ KЪЬЮЬ8ШLKШЧKШKШ ЧЪЯЬЮЬ6ЮЬШXKЪЬ8Ш8KХStartOfExpansion[s: BridgeComm.NetworkStream]ЪЮЬЮЬЮЬШ8KЪЬЮЬа*ШCKШKШ ЧЪЯЬЮЬЮЬ(ЮЬШmKЪЮЬЮЬЮЬШKЪЬЮЬШ	KШ>KШ8KЪЬЮЬШKШЧЧKШЧЧ ЕЧ    Ї  5  