events: try to improve perf by checking if impl already exists

this will break but just for the sake of it
nodejs · May 13, 2024 · 1d27fc5 · 1d27fc5
1 parent 190cb0d
commit 1d27fc5
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Showing 3 changed files with 5 additions and 21 deletions.
diff --git a/lib/internal/events/event_emitter.js b/lib/internal/events/event_emitter.js
@@ -32,7 +32,6 @@ const {
   kMaxEventTargetListeners,
   kMaxEventTargetListenersWarned,
   kImpl,
-  kPreInitiated,
   kIsFastPath,
   kSwitchToSlowPath,
   kInitialEvents,
@@ -223,13 +222,6 @@ ObjectDefineProperties(EventEmitter.prototype, {
     configurable: false,
     writable: true,
   },
-  [kPreInitiated]: {
-    __proto__: null,
-    value: false,
-    enumerable: false,
-    configurable: false,
-    writable: true,
-  },
   [kIsFastPath]: {
     __proto__: null,
     value: undefined,
@@ -360,7 +352,6 @@ EventEmitter.init = function(opts) {
 
   this._maxListeners = this._maxListeners || undefined;
 
-
   if (opts?.captureRejections) {
     validateBoolean(opts.captureRejections, 'options.captureRejections');
     this[kCapture] = Boolean(opts.captureRejections);
@@ -369,9 +360,7 @@ EventEmitter.init = function(opts) {
     // prototype lookup in a very sensitive hot path.
     this[kCapture] = EventEmitter.prototype[kCapture];
   }
-
-  if(this[kPreInitiated] === true) {
-    this[kPreInitiated] = false;
+  if(this[kImpl] !== undefined) {
     return;
   }
 

diff --git a/lib/internal/events/symbols.js b/lib/internal/events/symbols.js
@@ -17,7 +17,6 @@ const kMaxEventTargetListenersWarned =
 const kWatermarkData = SymbolFor('nodejs.watermarkData');
 
 const kImpl = Symbol('kImpl');
-const kPreInitiated = Symbol('kPreInitiated');
 const kIsFastPath = Symbol('kIsFastPath');
 const kSwitchToSlowPath = Symbol('kSwitchToSlowPath');
 const kRejection = SymbolFor('nodejs.rejection');
@@ -32,7 +31,6 @@ module.exports = {
   kMaxEventTargetListenersWarned,
   kWatermarkData,
   kImpl,
-  kPreInitiated,
   kIsFastPath,
   kSwitchToSlowPath,
   kRejection,

diff --git a/lib/internal/streams/readable.js b/lib/internal/streams/readable.js
@@ -43,7 +43,7 @@ Readable.ReadableState = ReadableState;
 
 const EE = require('events');
 const { Stream, prependListener } = require('internal/streams/legacy');
-const { kInitialEvents, kImpl, kShapeMode, kIsFastPath, kPreInitiated} = require('internal/events/symbols');
+const { kInitialEvents, kImpl, kShapeMode, kIsFastPath } = require('internal/events/symbols');
 const { Buffer } = require('buffer');
 
 const {
@@ -321,9 +321,9 @@ function Readable(options) {
   if (!(this instanceof Readable))
     return new Readable(options);
 
-  if (this[kImpl] === undefined && this._events === undefined) {
+  if (this[kImpl] === undefined) {
     this[kIsFastPath] = true;
-    this[kImpl] = new FastEventEmitter(this, this[kInitialEvents] !== undefined ? this[kInitialEvents] :{
+    this[kImpl] = new FastEventEmitter(this, this[kInitialEvents] === undefined ? {
       close: undefined,
       error: undefined,
       data: undefined,
@@ -336,10 +336,8 @@ function Readable(options) {
       // unpipe: undefined,
       // [destroyImpl.kConstruct]: undefined,
       // [destroyImpl.kDestroy]: undefined,
-    });
+    } : this[kInitialEvents]);
     this[kImpl][kShapeMode] = true;
-  } else {
-    this[kPreInitiated] = false;
   }
 
   this._readableState = new ReadableState(options, this, false);
@@ -367,7 +365,6 @@ function Readable(options) {
   }
 }
 
-Readable.prototype[kPreInitiated] = true;
 Readable.prototype.destroy = destroyImpl.destroy;
 Readable.prototype._undestroy = destroyImpl.undestroy;
 Readable.prototype._destroy = function(err, cb) {