From ab42dda007893c7629d916d794579c68b7ce9e34 Mon Sep 17 00:00:00 2001
From: Robert Nagy <ronagy@icloud.com>
Date: Thu, 12 Oct 2023 22:34:34 +0200
Subject: [PATCH] http: reduce parts in chunked response when corking

Refs: https://github.com/nodejs/performance/issues/57

PR-URL: https://github.com/nodejs/node/pull/50167
---
 lib/_http_outgoing.js | 63 ++++++++++++++++++++++++++++++++++---------
 1 file changed, 50 insertions(+), 13 deletions(-)

diff --git a/lib/_http_outgoing.js b/lib/_http_outgoing.js
index 178a3418dace0a..9caa80e3d13df4 100644
--- a/lib/_http_outgoing.js
+++ b/lib/_http_outgoing.js
@@ -82,6 +82,8 @@ let debug = require('internal/util/debuglog').debuglog('http', (fn) => {
 });
 
 const kCorked = Symbol('corked');
+const kChunkedBuffer = Symbol('kChunkedBuffer');
+const kChunkedLength = Symbol('kChunkedLength');
 const kUniqueHeaders = Symbol('kUniqueHeaders');
 const kBytesWritten = Symbol('kBytesWritten');
 const kErrored = Symbol('errored');
@@ -140,6 +142,8 @@ function OutgoingMessage(options) {
   this.finished = false;
   this._headerSent = false;
   this[kCorked] = 0;
+  this[kChunkedBuffer] = [];
+  this[kChunkedLength] = 0;
   this._closed = false;
 
   this.socket = null;
@@ -192,7 +196,7 @@ ObjectDefineProperty(OutgoingMessage.prototype, 'writableObjectMode', {
 ObjectDefineProperty(OutgoingMessage.prototype, 'writableLength', {
   __proto__: null,
   get() {
-    return this.outputSize + (this.socket ? this.socket.writableLength : 0);
+    return this.outputSize + this[kChunkedLength] + (this.socket ? this.socket.writableLength : 0);
   },
 });
 
@@ -206,8 +210,7 @@ ObjectDefineProperty(OutgoingMessage.prototype, 'writableHighWaterMark', {
 ObjectDefineProperty(OutgoingMessage.prototype, 'writableCorked', {
   __proto__: null,
   get() {
-    const corked = this.socket ? this.socket.writableCorked : 0;
-    return corked + this[kCorked];
+    return this[kCorked];
   },
 });
 
@@ -299,19 +302,45 @@ OutgoingMessage.prototype._renderHeaders = function _renderHeaders() {
 };
 
 OutgoingMessage.prototype.cork = function() {
+  this[kCorked]++;
   if (this.socket) {
     this.socket.cork();
-  } else {
-    this[kCorked]++;
   }
 };
 
 OutgoingMessage.prototype.uncork = function() {
+  this[kCorked]--;
   if (this.socket) {
     this.socket.uncork();
-  } else if (this[kCorked]) {
-    this[kCorked]--;
   }
+
+  if (this[kCorked] || this[kChunkedBuffer].length === 0) {
+    return;
+  }
+
+  const len = this[kChunkedLength];
+  const buf = this[kChunkedBuffer];
+
+  assert(this.chunkedEncoding);
+
+  let callbacks;
+  this._send(NumberPrototypeToString(len, 16), 'latin1', null);
+  this._send(crlf_buf, null, null);
+  for (let n = 0; n < buf.length; n += 3) {
+    this._send(buf[n + 0], buf[n + 1], null);
+    if (buf[n + 2]) {
+      callbacks ??= [];
+      callbacks.push(buf[n + 2]);
+    }
+  }
+  this._send(crlf_buf, null, callbacks.length ? (err) => {
+    for (const callback of callbacks) {
+      callback(err);
+    }
+  } : null);
+
+  this[kChunkedBuffer].length = 0;
+  this[kChunkedLength] = 0;
 };
 
 OutgoingMessage.prototype.setTimeout = function setTimeout(msecs, callback) {
@@ -937,11 +966,18 @@ function write_(msg, chunk, encoding, callback, fromEnd) {
 
   let ret;
   if (msg.chunkedEncoding && chunk.length !== 0) {
-    len ??= typeof chunk === 'string' ? Buffer.byteLength(chunk, encoding) : chunk.byteLength;
-    msg._send(NumberPrototypeToString(len, 16), 'latin1', null);
-    msg._send(crlf_buf, null, null);
-    msg._send(chunk, encoding, null, len);
-    ret = msg._send(crlf_buf, null, callback);
+    if (msg[kCorked] && msg._headerSent) {
+      len ??= typeof chunk === 'string' ? Buffer.byteLength(chunk, encoding) : chunk.byteLength;
+      msg[kChunkedBuffer].push(chunk, encoding, callback);
+      msg[kChunkedLength] += len;
+      ret = msg.outputSize + msg[kChunkedLength] < msg[kHighWaterMark];
+    } else {
+      len ??= typeof chunk === 'string' ? Buffer.byteLength(chunk, encoding) : chunk.byteLength;
+      msg._send(NumberPrototypeToString(len, 16), 'latin1', null);
+      msg._send(crlf_buf, null, null);
+      msg._send(chunk, encoding, null, len);
+      ret = msg._send(crlf_buf, null, callback);
+    }
   } else {
     ret = msg._send(chunk, encoding, callback, len);
   }
@@ -1068,7 +1104,8 @@ OutgoingMessage.prototype.end = function end(chunk, encoding, callback) {
     this.socket._writableState.corked = 1;
     this.socket.uncork();
   }
-  this[kCorked] = 0;
+  this[kCorked] = 1;
+  this.uncork();
 
   this.finished = true;