Stop exposing/using internal (private) variable within Scheduler

Author: ssoelvsten

rt/src/Asserts.mts

@@ -16,7 +16,7 @@ import { TroupeAggregateRawValue, TroupeRawValue } from './TroupeRawValue.mjs';
 // import { LVal } from './Lval';
 
 function _thread() {
-    return getRuntimeObject().__sched.__currentThread
+    return getRuntimeObject().__sched.getCurrentThread()
 }
 
 function __stringRep (v) {

rt/src/MailboxProcessor.mts

@@ -105,7 +105,7 @@ export class MailboxProcessor implements MailboxInterface {
 
 
     peek(lev: Level, index: number, lowb: Level, highb: Level) {        
-        let theThread = this.sched.__currentThread
+        let theThread = this.sched.getCurrentThread()
         let mb = theThread.mailbox;
         debug (`peek index: ${index}`)        
         debug (`peek interval: [${lowb.stringRep()}, ${highb.stringRep()}]`)
@@ -138,7 +138,7 @@ export class MailboxProcessor implements MailboxInterface {
     }
 
     consume(lev: Level, index: number, lowb: Level, highb: Level) {
-        let theThread = this.sched.__currentThread
+        let theThread = this.sched.getCurrentThread()
         let mb = theThread.mailbox;
         debug (`consume index: ${index}`)        
         debug (`consume interval: [${lowb.stringRep()} to ${highb.stringRep()}]`)

rt/src/Scheduler.mts

@@ -158,6 +158,18 @@ export class Scheduler implements SchedulerInterface {
         return this.__alive[tid.val.toString()];
     }
 
+    /** The currently scheduled thread */
+    getCurrentThread() {
+        return this.__currentThread;
+    }
+
+    /** Overwrites the current thread; the previously current thread is returned. */
+    setCurrentThread(t: Thread) {
+        const prev = this.__currentThread
+        this.__currentThread = t;
+        return prev;
+    }
+
     /*************************************************************************************************\
     Thread blocking/unblocking
     \*************************************************************************************************/

rt/src/SchedulerInterface.mts

@@ -3,8 +3,6 @@ import { LVal } from './Lval.mjs'
 import { Level } from "./Level.mjs";
 
 export interface SchedulerInterface {
-    __currentThread: Thread;
-
     resetScheduler(): void;
 
     scheduleNewThread(fun: () => any, arg: any, pc: Level, block: Level): LVal;
@@ -15,6 +13,8 @@ export interface SchedulerInterface {
 
     isAlive(tid: LVal): boolean;
     getThread(tid: LVal): Thread;
+    getCurrentThread(): Thread;
+    setCurrentThread(t: Thread): Thread;
 
     stopThreadWithErrorMessage (t: Thread, errMsg: string): void
 

rt/src/builtins/UserRuntimeZero.mts

@@ -259,21 +259,20 @@ export class UserRuntimeZero {
 
 
     libLoadingPseudoThread = new Thread(null, null, null, __unit, levels.BOT, levels.BOT, null, this, null);
-    savedThread =  null ;// this.runtime.__sched.__currentThread;
+    savedThread =  null ;// this.runtime.__sched.getCurrentThread();
     setLibloadMode() {
         this.mkVal = (x) => new LVal(x, levels.BOT);
         this.mkValPos = (x, pos) => new LVal(x, levels.BOT, levels.BOT, pos);
         this.Env = LibEnv;
-        this.savedThread = this.runtime.__sched.__currentThread;
-        this.runtime.__sched.__currentThread = this.libLoadingPseudoThread;
+        this.savedThread = this.runtime.__sched.setCurrentThread(this.libLoadingPseudoThread);
     }
 
 
     setNormalMode() {
         this.mkVal = this.default_mkVal;
         this.mkValPos = this.default_mkValPos
         this.Env = RtEnv;
-        this.runtime.__sched.__currentThread = this.savedThread;
+        this.runtime.__sched.setCurrentThread(this.savedThread);
     }
 
     // tailcall(lff, arg) {    

rt/src/builtins/monitor.mts

@@ -19,7 +19,7 @@ export function BuiltinMonitors <TBase extends Constructor<UserRuntimeZero>> (Ba
 
             let r = this.runtime.rt_mkuuid();
             if (t) {
-                t.addMonitor(this.runtime.__sched.__currentThread.tid, r);
+                t.addMonitor(this.runtime.__sched.getCurrentThread().tid, r);
             }
 
             return this.runtime.ret(r);

rt/src/builtins/receive.mts

@@ -133,7 +133,7 @@ export function BuiltinReceive<TBase extends Constructor<UserRuntimeZero>>(Base:
 
         _blockThread = mkBase ((arg) => {
           assertIsUnit(arg)
-          this.runtime.__sched.blockThread(this.runtime.__sched.__currentThread);
+          this.runtime.__sched.blockThread(this.runtime.__sched.getCurrentThread());
           return null;
         })
 

rt/src/builtins/self.mts

@@ -8,7 +8,7 @@ import { UserRuntimeZero, Constructor, mkBase } from './UserRuntimeZero.mjs'
 export function BuiltinSelf<TBase extends Constructor<UserRuntimeZero>>(Base: TBase) {
     return class extends Base {
         self = mkBase((arg) => {
-            return this.runtime.ret(this.runtime.__sched.__currentThread.tid);
+            return this.runtime.ret(this.runtime.__sched.getCurrentThread().tid);
         }, "self");
     }
 }

rt/src/runtimeMonitored.mts

@@ -48,7 +48,7 @@ const rt_xconsole =
                  });
 
 /** Returns the current thread */
-function $t():Thread { return __sched.__currentThread };
+function $t():Thread { return __sched.getCurrentThread() };
 
 // --------------------------------------------------