From 4b27087b30d87d590152cc177c7c4a8886e78f48 Mon Sep 17 00:00:00 2001
From: Robert Nagy <ronagy@icloud.com>
Date: Wed, 4 Oct 2023 12:13:06 +0200
Subject: [PATCH] stream: optimize Writable

PR-URL: https://github.com/nodejs/node/pull/50012
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com>
---
 lib/internal/streams/writable.js | 32 ++++++++++++++++++++++----------
 1 file changed, 22 insertions(+), 10 deletions(-)

diff --git a/lib/internal/streams/writable.js b/lib/internal/streams/writable.js
index 5800c9df171ff2..8b44731b462a95 100644
--- a/lib/internal/streams/writable.js
+++ b/lib/internal/streams/writable.js
@@ -108,6 +108,7 @@ const kWriteCb = 1 << 26;
 const kExpectWriteCb = 1 << 27;
 const kAfterWriteTickInfo = 1 << 28;
 const kAfterWritePending = 1 << 29;
+const kHasBuffer = 1 << 30;
 
 // TODO(benjamingr) it is likely slower to do it this way than with free functions
 function makeBitMapDescriptor(bit) {
@@ -340,6 +341,7 @@ function resetBuffer(state) {
   state.buffered = [];
   state.bufferedIndex = 0;
   state.state |= kAllBuffers | kAllNoop;
+  state.state &= ~kHasBuffer;
 }
 
 WritableState.prototype.getBuffer = function getBuffer() {
@@ -396,11 +398,13 @@ function Writable(options) {
   destroyImpl.construct(this, () => {
     const state = this._writableState;
 
-    if (!state.writing) {
+    if ((state.state & kWriting) === 0) {
       clearBuffer(this, state);
     }
 
-    finishMaybe(this, state);
+    if ((state.state & kEnding) !== 0) {
+      finishMaybe(this, state);
+    }
   });
 }
 
@@ -523,6 +527,7 @@ function writeOrBuffer(stream, state, chunk, encoding, callback) {
 
   if ((state.state & (kWriting | kErrored | kCorked | kConstructed)) !== kConstructed) {
     state.buffered.push({ chunk, encoding, callback });
+    state.state |= kHasBuffer;
     if ((state.state & kAllBuffers) !== 0 && encoding !== 'buffer') {
       state.state &= ~kAllBuffers;
     }
@@ -591,8 +596,9 @@ function onwrite(stream, er) {
     // Avoid V8 leak, https://github.com/nodejs/node/pull/34103#issuecomment-652002364
     er.stack; // eslint-disable-line no-unused-expressions
 
-    if (!state.errored) {
-      state.errored = er;
+    if ((state.state & kErrored) === 0) {
+      state[kErroredValue] = er;
+      state.state |= kErrored;
     }
 
     // In case of duplex streams we need to notify the readable side of the
@@ -607,12 +613,12 @@ function onwrite(stream, er) {
       onwriteError(stream, state, er, cb);
     }
   } else {
-    if (state.buffered.length > state.bufferedIndex) {
+    if ((state.state & kHasBuffer) !== 0) {
       clearBuffer(stream, state);
     }
 
     if (sync) {
-      const needDrain = state.length === 0 && (state.state & kNeedDrain) !== 0;
+      const needDrain = (state.state & kNeedDrain) !== 0 && state.length === 0;
       const needTick = needDrain || (state.state & kDestroyed !== 0) || cb !== nop;
 
       // It is a common case that the callback passed to .write() is always
@@ -625,7 +631,9 @@ function onwrite(stream, er) {
           state.state |= kAfterWritePending;
         } else {
           state.pendingcb--;
-          finishMaybe(stream, state, true);
+          if ((state.state & kEnding) !== 0) {
+            finishMaybe(stream, state, true);
+          }
         }
       } else if ((state.state & kAfterWriteTickInfo) !== 0 &&
                  state[kAfterWriteTickInfoValue].cb === cb) {
@@ -636,7 +644,9 @@ function onwrite(stream, er) {
         state.state |= (kAfterWritePending | kAfterWriteTickInfo);
       } else {
         state.pendingcb--;
-        finishMaybe(stream, state, true);
+        if ((state.state & kEnding) !== 0) {
+          finishMaybe(stream, state, true);
+        }
       }
     } else {
       afterWrite(stream, state, 1, cb);
@@ -668,7 +678,9 @@ function afterWrite(stream, state, count, cb) {
     errorBuffer(state);
   }
 
-  finishMaybe(stream, state);
+  if ((state.state & kEnding) !== 0) {
+    finishMaybe(stream, state, true);
+  }
 }
 
 // If there's something in the buffer waiting, then invoke callbacks.
@@ -692,7 +704,7 @@ function errorBuffer(state) {
 
 // If there's something in the buffer waiting, then process it.
 function clearBuffer(stream, state) {
-  if ((state.state & (kDestroyed | kBufferProcessing | kCorked)) !== 0 ||
+  if ((state.state & (kDestroyed | kBufferProcessing | kCorked | kHasBuffer)) !== kHasBuffer ||
     (state.state & kConstructed) === 0) {
     return;
   }