src,lib: make JSTransferables based on private symbols

Serializes and transfers platform objects implemented as a JS class based on private symbols instead of V8 object internal slots. This avoids the need to alter the prototype chains and mixins to make the JS class to be transferable.
nodejs · nodejs-github-bot · Jul 7, 2023 · Apr 9, 2023 · Apr 13, 2023 · May 6, 2023
commit b61b4c91d95b89acb8c2a86b22a9f31213a26031
diff --git a/lib/internal/abort_controller.js b/lib/internal/abort_controller.js
@@ -58,15 +58,15 @@ const {
 const assert = require('internal/assert');
 
 const {
-  messaging_deserialize_symbol: kDeserialize,
-  messaging_transfer_symbol: kTransfer,
-  messaging_transfer_list_symbol: kTransferList,
-} = internalBinding('symbols');
+  kDeserialize,
+  kTransfer,
+  kTransferList,
+} = require('internal/worker/js_transferable');
 
 let _MessageChannel;
-let makeTransferable;
+let markTransferMode;
 
-// Loading the MessageChannel and makeTransferable have to be done lazily
+// Loading the MessageChannel and markTransferable have to be done lazily
 // because otherwise we'll end up with a require cycle that ends up with
 // an incomplete initialization of abort_controller.
 
@@ -75,10 +75,10 @@ function lazyMessageChannel() {
   return new _MessageChannel();
 }
 
-function lazyMakeTransferable(obj) {
-  makeTransferable ??=
-    require('internal/worker/js_transferable').makeTransferable;
-  return makeTransferable(obj);
+function lazyMarkTransferMode(obj, cloneable, transferable) {
+  markTransferMode ??=
+    require('internal/worker/js_transferable').markTransferMode;
+  markTransferMode(obj, cloneable, transferable);
 }
 
 const clearTimeoutRegistry = new SafeFinalizationRegistry(clearTimeout);
@@ -355,7 +355,10 @@ function createAbortSignal(init = kEmptyObject) {
   signal[kAborted] = aborted;
   signal[kReason] = reason;
   signal[kComposite] = composite;
-  return transferable ? lazyMakeTransferable(signal) : signal;
+  if (transferable) {
+    lazyMarkTransferMode(signal, false, true);
+  }
+  return signal;
 }
 
 function abortSignal(signal, reason) {
@@ -411,7 +414,8 @@ class AbortController {
 function transferableAbortSignal(signal) {
   if (signal?.[kAborted] === undefined)
     throw new ERR_INVALID_ARG_TYPE('signal', 'AbortSignal', signal);
-  return lazyMakeTransferable(signal);
+  lazyMarkTransferMode(signal, false, true);
+  return signal;
 }
 
 /**

diff --git a/lib/internal/blob.js b/lib/internal/blob.js
@@ -32,7 +32,7 @@ const {
 const { URL } = require('internal/url');
 
 const {
-  makeTransferable,
+  markTransferMode,
   kClone,
   kDeserialize,
 } = require('internal/worker/js_transferable');
@@ -136,6 +136,8 @@ class Blob {
    * @constructs {Blob}
    */
   constructor(sources = [], options) {
+    markTransferMode(this, true, false);
+
     if (sources === null ||
         typeof sources[SymbolIterator] !== 'function' ||
         typeof sources === 'string') {
@@ -167,9 +169,6 @@ class Blob {
     type = `${type}`;
     this[kType] = RegExpPrototypeExec(disallowedTypeCharacters, type) !== null ?
       '' : StringPrototypeToLowerCase(type);
-
-    // eslint-disable-next-line no-constructor-return
-    return makeTransferable(this);
   }
 
   [kInspect](depth, options) {
@@ -385,16 +384,19 @@ class Blob {
 }
 
 function ClonedBlob() {
-  return makeTransferable(ReflectConstruct(function() {}, [], Blob));
+  return ReflectConstruct(function() {
+    markTransferMode(this, true, false);
+  }, [], Blob);
 }
 ClonedBlob.prototype[kDeserialize] = () => {};
 
 function createBlob(handle, length, type = '') {
-  return makeTransferable(ReflectConstruct(function() {
+  return ReflectConstruct(function() {
+    markTransferMode(this, true, false);
     this[kHandle] = handle;
     this[kType] = type;
     this[kLength] = length;
-  }, [], Blob));
+  }, [], Blob);
 }
 
 ObjectDefineProperty(Blob.prototype, SymbolToStringTag, {

diff --git a/lib/internal/blocklist.js b/lib/internal/blocklist.js
@@ -20,7 +20,7 @@ const {
 } = require('internal/socketaddress');
 
 const {
-  JSTransferable,
+  markTransferMode,
   kClone,
   kDeserialize,
 } = require('internal/worker/js_transferable');
@@ -36,9 +36,9 @@ const {
 
 const { validateInt32, validateString } = require('internal/validators');
 
-class BlockList extends JSTransferable {
+class BlockList {
   constructor() {
-    super();
+    markTransferMode(this, true, false);
     this[kHandle] = new BlockListHandle();
     this[kHandle][owner_symbol] = this;
   }
@@ -148,9 +148,9 @@ class BlockList extends JSTransferable {
   }
 }
 
-class InternalBlockList extends JSTransferable {
+class InternalBlockList {
   constructor(handle) {
-    super();
+    markTransferMode(this, true, false);
     this[kHandle] = handle;
     if (handle !== undefined)
       handle[owner_symbol] = this;

diff --git a/lib/internal/crypto/keys.js b/lib/internal/crypto/keys.js
@@ -57,7 +57,7 @@ const {
 } = require('internal/util/types');
 
 const {
-  makeTransferable,
+  markTransferMode,
   kClone,
   kDeserialize,
 } = require('internal/worker/js_transferable');
@@ -706,24 +706,22 @@ ObjectDefineProperties(CryptoKey.prototype, {
 // All internal code must use new InternalCryptoKey to create
 // CryptoKey instances. The CryptoKey class is exposed to end
 // user code but is not permitted to be constructed directly.
-// Using makeTransferable also allows the CryptoKey to be
+// Using markTransferMode also allows the CryptoKey to be
 // cloned to Workers.
 class InternalCryptoKey {
   constructor(
     keyObject,
     algorithm,
     keyUsages,
     extractable) {
+    markTransferMode(this, true, false);
     // Using symbol properties here currently instead of private
     // properties because (for now) the performance penalty of
     // private fields is still too high.
     this[kKeyObject] = keyObject;
     this[kAlgorithm] = algorithm;
     this[kExtractable] = extractable;
     this[kKeyUsages] = keyUsages;
-
-    // eslint-disable-next-line no-constructor-return
-    return makeTransferable(this);
   }
 
   [kClone]() {

diff --git a/lib/internal/crypto/x509.js b/lib/internal/crypto/x509.js
@@ -48,7 +48,7 @@ const {
 } = require('internal/errors');
 
 const {
-  JSTransferable,
+  markTransferMode,
   kClone,
   kDeserialize,
 } = require('internal/worker/js_transferable');
@@ -94,16 +94,16 @@ function getFlags(options = kEmptyObject) {
   return flags;
 }
 
-class InternalX509Certificate extends JSTransferable {
+class InternalX509Certificate {
   [kInternalState] = new SafeMap();
 
   constructor(handle) {
-    super();
+    markTransferMode(this, true, false);
     this[kHandle] = handle;
   }
 }
 
-class X509Certificate extends JSTransferable {
+class X509Certificate {
   [kInternalState] = new SafeMap();
 
   constructor(buffer) {
@@ -115,7 +115,7 @@ class X509Certificate extends JSTransferable {
         ['string', 'Buffer', 'TypedArray', 'DataView'],
         buffer);
     }
-    super();
+    markTransferMode(this, true, false);
     this[kHandle] = parseX509(buffer);
   }
 

diff --git a/lib/internal/event_target.js b/lib/internal/event_target.js
@@ -10,11 +10,7 @@ const {
   ObjectDefineProperties,
   ObjectDefineProperty,
   ObjectGetOwnPropertyDescriptor,
-  ObjectGetOwnPropertyDescriptors,
-  ObjectSetPrototypeOf,
-  ObjectValues,
   ReflectApply,
-  SafeArrayIterator,
   SafeFinalizationRegistry,
   SafeMap,
   SafeWeakMap,
@@ -1114,30 +1110,9 @@ function defineEventHandler(emitter, name, event = name) {
   });
 }
 
-const EventEmitterMixin = (Superclass) => {
-  class MixedEventEmitter extends Superclass {
-    constructor(...args) {
-      args = new SafeArrayIterator(args);
-      super(...args);
-      FunctionPrototypeCall(EventEmitter, this);
-    }
-  }
-  const protoProps = ObjectGetOwnPropertyDescriptors(EventEmitter.prototype);
-  delete protoProps.constructor;
-  const propertiesValues = ObjectValues(protoProps);
-  for (let i = 0; i < propertiesValues.length; i++) {
-    // We want to use null-prototype objects to not rely on globally mutable
-    // %Object.prototype%.
-    ObjectSetPrototypeOf(propertiesValues[i], null);
-  }
-  ObjectDefineProperties(MixedEventEmitter.prototype, protoProps);
-  return MixedEventEmitter;
-};
-
 module.exports = {
   Event,
   CustomEvent,
-  EventEmitterMixin,
   EventTarget,
   NodeEventTarget,
   defineEventHandler,

diff --git a/lib/internal/fs/promises.js b/lib/internal/fs/promises.js
@@ -90,7 +90,7 @@ const {
   lazyDOMException,
   promisify,
 } = require('internal/util');
-const { EventEmitterMixin } = require('internal/event_target');
+const EventEmitter = require('events');
 const { StringDecoder } = require('string_decoder');
 const { kFSWatchStart, watch } = require('internal/fs/watchers');
 const nonNativeWatcher = require('internal/fs/recursive_watch');
@@ -110,7 +110,7 @@ const kLocked = Symbol('kLocked');
 const { kUsePromises } = binding;
 const { Interface } = require('internal/readline/interface');
 const {
-  JSTransferable, kDeserialize, kTransfer, kTransferList,
+  kDeserialize, kTransfer, kTransferList, markTransferMode,
 } = require('internal/worker/js_transferable');
 
 const getDirectoryEntriesPromise = promisify(getDirents);
@@ -130,12 +130,13 @@ function lazyFsStreams() {
   return fsStreams ??= require('internal/fs/streams');
 }
 
-class FileHandle extends EventEmitterMixin(JSTransferable) {
+class FileHandle extends EventEmitter {
   /**
    * @param {InternalFSBinding.FileHandle | undefined} filehandle
    */
   constructor(filehandle) {
     super();
+    markTransferMode(this, false, true);
     this[kHandle] = filehandle;
     this[kFd] = filehandle ? filehandle.fd : -1;
 

diff --git a/lib/internal/histogram.js b/lib/internal/histogram.js
@@ -45,7 +45,7 @@ const kRecordable = Symbol('kRecordable');
 const {
   kClone,
   kDeserialize,
-  makeTransferable,
+  markTransferMode,
 } = require('internal/worker/js_transferable');
 
 function isHistogram(object) {
@@ -319,21 +319,23 @@ class RecordableHistogram extends Histogram {
 }
 
 function internalHistogram(handle) {
-  return makeTransferable(ReflectConstruct(
+  return ReflectConstruct(
     function() {
+      markTransferMode(this, true, false);
       this[kHandle] = handle;
       this[kMap] = new SafeMap();
-    }, [], Histogram));
+    }, [], Histogram);
 }
 internalHistogram.prototype[kDeserialize] = () => {};
 
 function internalRecordableHistogram(handle) {
-  return makeTransferable(ReflectConstruct(
+  return ReflectConstruct(
     function() {
+      markTransferMode(this, true, false);
       this[kHandle] = handle;
       this[kMap] = new SafeMap();
       this[kRecordable] = true;
-    }, [], RecordableHistogram));
+    }, [], RecordableHistogram);
 }
 internalRecordableHistogram.prototype[kDeserialize] = () => {};
 

diff --git a/lib/internal/perf/event_loop_delay.js b/lib/internal/perf/event_loop_delay.js
@@ -32,7 +32,7 @@ const {
 } = require('internal/util');
 
 const {
-  makeTransferable,
+  markTransferMode,
 } = require('internal/worker/js_transferable');
 
 const kEnabled = Symbol('kEnabled');
@@ -79,12 +79,13 @@ function monitorEventLoopDelay(options = kEmptyObject) {
   const { resolution = 10 } = options;
   validateInteger(resolution, 'options.resolution', 1);
 
-  return makeTransferable(ReflectConstruct(
+  return ReflectConstruct(
     function() {
+      markTransferMode(this, true, false);
       this[kEnabled] = false;
       this[kHandle] = createELDHistogram(resolution);
       this[kMap] = new SafeMap();
-    }, [], ELDHistogram));
+    }, [], ELDHistogram);
 }
 
 module.exports = monitorEventLoopDelay;
diff --git a/lib/internal/socketaddress.js b/lib/internal/socketaddress.js
@@ -32,21 +32,22 @@ const {
 const { inspect } = require('internal/util/inspect');
 
 const {
-  JSTransferable,
+  markTransferMode,
   kClone,
   kDeserialize,
 } = require('internal/worker/js_transferable');
 
 const kHandle = Symbol('kHandle');
 const kDetail = Symbol('kDetail');
 
-class SocketAddress extends JSTransferable {
+class SocketAddress {
   static isSocketAddress(value) {
     return value?.[kHandle] !== undefined;
   }
 
   constructor(options = kEmptyObject) {
-    super();
+    markTransferMode(this, true, false);
+
     validateObject(options, 'options');
     let { family = 'ipv4' } = options;
     const {
@@ -139,9 +140,10 @@ class SocketAddress extends JSTransferable {
   }
 }
 
-class InternalSocketAddress extends JSTransferable {
+class InternalSocketAddress {
   constructor(handle) {
-    super();
+    markTransferMode(this, true, false);
+
     this[kHandle] = handle;
     this[kDetail] = this[kHandle]?.detail({
       address: undefined,