process: split worker IO into internal/worker/io.js

- Move `setupProcessStdio` which contains write access to
the process object into `bootstrap/node.js`
- Move `MessagePort`, `MessageChannel`, `ReadableWorkerStdio`,
and `WritableWorkerStdio` into `internal/worker/io.js`
- Move more worker-specific bootstrap code into
`internal/process/worker_thread_only` from `setupChild`
in `internal/worker.js`, and move the `process._fatalException`
overwrite into `bootstrap/node.js` for clarity.
PR-URL: #25199
Reviewed-By: James M Snell <jasnell@gmail.com>

Author: joyeecheung

lib/internal/bootstrap/node.js

@@ -140,9 +140,13 @@ function startup() {
 }
 
 if(isMainThread){
-mainThreadSetup.setupStdio();
+const{ getStdout, getStdin, getStderr }=
+NativeModule.require('internal/process/stdio').getMainThreadStdio();
+setupProcessStdio(getStdout,getStdin,getStderr);
 }else{
-workerThreadSetup.setupStdio();
+const{ getStdout, getStdin, getStderr }=
+workerThreadSetup.initializeWorkerStdio();
+setupProcessStdio(getStdout,getStdin,getStderr);
 }
 
 if(global.__coverage__)
@@ -318,8 +322,14 @@ function startup() {
 functionstartExecution(){
 // This means we are in a Worker context, and any script execution
 // will be directed by the worker module.
-if(internalBinding('worker').getEnvMessagePort()!==undefined){
-NativeModule.require('internal/worker').setupChild();
+if(!isMainThread){
+constworkerThreadSetup=NativeModule.require(
+'internal/process/worker_thread_only'
+);
+// Set up the message port and start listening
+const{ workerFatalExeception }=workerThreadSetup.setup();
+// Overwrite fatalException
+process._fatalException=workerFatalExeception;
 return;
 }
 
@@ -511,6 +521,31 @@ function setupProcessObject() {
 EventEmitter.call(process);
 }
 
+functionsetupProcessStdio(getStdout,getStdin,getStderr){
+Object.defineProperty(process,'stdout',{
+configurable: true,
+enumerable: true,
+get: getStdout
+});
+
+Object.defineProperty(process,'stderr',{
+configurable: true,
+enumerable: true,
+get: getStderr
+});
+
+Object.defineProperty(process,'stdin',{
+configurable: true,
+enumerable: true,
+get: getStdin
+});
+
+process.openStdin=function(){
+process.stdin.resume();
+returnprocess.stdin;
+};
+}
+
 functionsetupGlobalVariables(){
 Object.defineProperty(global,Symbol.toStringTag,{
 value: 'global',

lib/internal/process/main_thread_only.js

@@ -16,15 +16,6 @@ const {
  validateString
 }=require('internal/validators');
 
-const{
- setupProcessStdio,
- getMainThreadStdio
-}=require('internal/process/stdio');
-
-functionsetupStdio(){
-setupProcessStdio(getMainThreadStdio());
-}
-
 // The execution of this function itself should not cause any side effects.
 functionwrapProcessMethods(binding){
 functionchdir(directory){
@@ -174,7 +165,6 @@ function setupChildProcessIpcChannel() {
 }
 
 module.exports={
- setupStdio,
  wrapProcessMethods,
  setupSignalHandlers,
  setupChildProcessIpcChannel,

lib/internal/process/stdio.js

@@ -1,6 +1,5 @@
 'use strict';
 
-exports.setupProcessStdio=setupProcessStdio;
 exports.getMainThreadStdio=getMainThreadStdio;
 
 functiondummyDestroy(err,cb){cb(err);}
@@ -134,31 +133,6 @@ function getMainThreadStdio() {
 };
 }
 
-functionsetupProcessStdio({ getStdout, getStdin, getStderr }){
-Object.defineProperty(process,'stdout',{
-configurable: true,
-enumerable: true,
-get: getStdout
-});
-
-Object.defineProperty(process,'stderr',{
-configurable: true,
-enumerable: true,
-get: getStderr
-});
-
-Object.defineProperty(process,'stdin',{
-configurable: true,
-enumerable: true,
-get: getStdin
-});
-
-process.openStdin=function(){
-process.stdin.resume();
-returnprocess.stdin;
-};
-}
-
 functioncreateWritableStdioStream(fd){
 varstream;
 consttty_wrap=internalBinding('tty_wrap');

lib/internal/process/worker_thread_only.js

@@ -2,23 +2,54 @@
 
 // This file contains process bootstrappers that can only be
 // run in the worker thread.
+const{
+ getEnvMessagePort,
+ threadId
+}=internalBinding('worker');
+
+constdebug=require('util').debuglog('worker');
 
 const{
- setupProcessStdio
-}=require('internal/process/stdio');
+ kWaitingStreams,
+ ReadableWorkerStdio,
+ WritableWorkerStdio
+}=require('internal/worker/io');
 
 const{
- workerStdio
+ createMessageHandler,
+ createWorkerFatalExeception
 }=require('internal/worker');
 
-functionsetupStdio(){
-setupProcessStdio({
-getStdout: ()=>workerStdio.stdout,
-getStderr: ()=>workerStdio.stderr,
-getStdin: ()=>workerStdio.stdin
-});
+constworkerStdio={};
+
+functioninitializeWorkerStdio(){
+constport=getEnvMessagePort();
+port[kWaitingStreams]=0;
+workerStdio.stdin=newReadableWorkerStdio(port,'stdin');
+workerStdio.stdout=newWritableWorkerStdio(port,'stdout');
+workerStdio.stderr=newWritableWorkerStdio(port,'stderr');
+
+return{
+getStdout(){returnworkerStdio.stdout;},
+getStderr(){returnworkerStdio.stderr;},
+getStdin(){returnworkerStdio.stdin;}
+};
+}
+
+functionsetup(){
+debug(`[${threadId}] is setting up worker child environment`);
+
+constport=getEnvMessagePort();
+constpublicWorker=require('worker_threads');
+port.on('message',createMessageHandler(publicWorker,port,workerStdio));
+port.start();
+
+return{
+workerFatalExeception: createWorkerFatalExeception(port)
+};
 }
 
 module.exports={
- setupStdio
+ initializeWorkerStdio,
+ setup
 };