From cf071a01f2297834057039b8a973b06be2f2da2d Mon Sep 17 00:00:00 2001
From: Matteo Collina <hello@matteocollina.com>
Date: Wed, 24 Jul 2019 15:56:13 +0200
Subject: [PATCH] stream: resolve perf regression introduced by V8 7.3
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This commit contains two fixes:
1. use instanceof instead of Object.getPrototypeOf, as checking an
   object prototype with Object.getPrototypeOf is slower
   than an instanceof check.
2. avoid parseInt(undefined, 10) to get NaN as it regressed.

PR-URL: https://github.com/nodejs/node/pull/28842
Fixes: https://github.com/nodejs/node/issues/28586
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Anto Aravinth <anto.aravinth.cse@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
---
 lib/_stream_readable.js | 11 +++++++++--
 lib/_stream_writable.js |  3 ++-
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/lib/_stream_readable.js b/lib/_stream_readable.js
index 76077a117ad5d8..31cddbedac93a5 100644
--- a/lib/_stream_readable.js
+++ b/lib/_stream_readable.js
@@ -250,7 +250,8 @@ function readableAddChunk(stream, chunk, encoding, addToFront) {
     } else if (state.objectMode || chunk && chunk.length > 0) {
       if (typeof chunk !== 'string' &&
           !state.objectMode &&
-          Object.getPrototypeOf(chunk) !== Buffer.prototype) {
+          // Do not use Object.getPrototypeOf as it is slower since V8 7.3.
+          !(chunk instanceof Buffer)) {
         chunk = Stream._uint8ArrayToBuffer(chunk);
       }
 
@@ -393,7 +394,13 @@ function howMuchToRead(n, state) {
 // You can override either this method, or the async _read(n) below.
 Readable.prototype.read = function(n) {
   debug('read', n);
-  n = parseInt(n, 10);
+  // Same as parseInt(undefined, 10), however V8 7.3 performance regressed
+  // in this scenario, so we are doing it manually.
+  if (n === undefined) {
+    n = NaN;
+  } else if (!Number.isInteger(n)) {
+    n = parseInt(n, 10);
+  }
   const state = this._readableState;
   const nOrig = n;
 
diff --git a/lib/_stream_writable.js b/lib/_stream_writable.js
index e85b4dead859bc..bf9abeeed81d45 100644
--- a/lib/_stream_writable.js
+++ b/lib/_stream_writable.js
@@ -277,7 +277,8 @@ Writable.prototype.write = function(chunk, encoding, cb) {
   var ret = false;
   const isBuf = !state.objectMode && Stream._isUint8Array(chunk);
 
-  if (isBuf && Object.getPrototypeOf(chunk) !== Buffer.prototype) {
+  // Do not use Object.getPrototypeOf as it is slower since V8 7.3.
+  if (isBuf && !(chunk instanceof Buffer)) {
     chunk = Stream._uint8ArrayToBuffer(chunk);
   }