From def55f80a11410008e045447cb147daf52d40782 Mon Sep 17 00:00:00 2001
From: Robert Nagy <ronagy@icloud.com>
Date: Sun, 1 Oct 2023 22:07:12 +0200
Subject: [PATCH] stream: avoid tick in writable hot path

PR-URL: https://github.com/nodejs/node/pull/49966
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
---
 lib/internal/streams/writable.js | 28 +++++++++++++++++++---------
 1 file changed, 19 insertions(+), 9 deletions(-)

diff --git a/lib/internal/streams/writable.js b/lib/internal/streams/writable.js
index 7b1896baeb47c2..5800c9df171ff2 100644
--- a/lib/internal/streams/writable.js
+++ b/lib/internal/streams/writable.js
@@ -612,24 +612,31 @@ function onwrite(stream, er) {
     }
 
     if (sync) {
+      const needDrain = state.length === 0 && (state.state & kNeedDrain) !== 0;
+      const needTick = needDrain || (state.state & kDestroyed !== 0) || cb !== nop;
+
       // It is a common case that the callback passed to .write() is always
       // the same. In that case, we do not schedule a new nextTick(), but
       // rather just increase a counter, to improve performance and avoid
       // memory allocations.
       if (cb === nop) {
-        if ((state.state & kAfterWritePending) === 0) {
+        if ((state.state & kAfterWritePending) === 0 && needTick) {
           process.nextTick(afterWrite, stream, state, 1, cb);
           state.state |= kAfterWritePending;
         } else {
-          state.pendingcb -= 1;
+          state.pendingcb--;
+          finishMaybe(stream, state, true);
         }
-      } else if (state.afterWriteTickInfo !== null &&
-                 state.afterWriteTickInfo.cb === cb) {
-        state.afterWriteTickInfo.count++;
+      } else if ((state.state & kAfterWriteTickInfo) !== 0 &&
+                 state[kAfterWriteTickInfoValue].cb === cb) {
+        state[kAfterWriteTickInfoValue].count++;
+      } else if (needTick) {
+        state[kAfterWriteTickInfoValue] = { count: 1, cb, stream, state };
+        process.nextTick(afterWriteTick, state[kAfterWriteTickInfoValue]);
+        state.state |= (kAfterWritePending | kAfterWriteTickInfo);
       } else {
-        state.afterWriteTickInfo = { count: 1, cb, stream, state };
-        process.nextTick(afterWriteTick, state.afterWriteTickInfo);
-        state.state |= kAfterWritePending;
+        state.pendingcb--;
+        finishMaybe(stream, state, true);
       }
     } else {
       afterWrite(stream, state, 1, cb);
@@ -638,7 +645,8 @@ function onwrite(stream, er) {
 }
 
 function afterWriteTick({ stream, state, count, cb }) {
-  state.afterWriteTickInfo = null;
+  state.state &= ~kAfterWriteTickInfo;
+  state[kAfterWriteTickInfoValue] = null;
   return afterWrite(stream, state, count, cb);
 }
 
@@ -795,6 +803,8 @@ Writable.prototype.end = function(chunk, encoding, cb) {
   if (typeof cb === 'function') {
     if (err) {
       process.nextTick(cb, err);
+    } else if ((state.state & kErrored) !== 0) {
+      process.nextTick(cb, state[kErroredValue]);
     } else if ((state.state & kFinished) !== 0) {
       process.nextTick(cb, null);
     } else {