fs: add `bufferSize` option to `fs.opendir()`

Add an option that controls the size of the internal
buffer.

Fixes: https://github.com/nodejs/node/issues/29941

PR-URL: https://github.com/nodejs/node/pull/30114
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

1 files changed, 7 insertions, 5 deletions

diff --git a/benchmark/fs/bench-opendir.js b/benchmark/fs/bench-opendir.js
index 419c3a231a..20e178d9cc 100644
--- a/benchmark/fs/bench-opendir.js
+++ b/benchmark/fs/bench-opendir.js
@@ -7,10 +7,11 @@ const path = require('path');
 const bench = common.createBenchmark(main, {
   n: [100],
   dir: [ 'lib', 'test/parallel'],
-  mode: [ 'async', 'sync', 'callback' ]
+  mode: [ 'async', 'sync', 'callback' ],
+  bufferSize: [ 4, 32, 1024 ]
 });
 
-async function main({ n, dir, mode }) {
+async function main({ n, dir, mode, bufferSize }) {
   const fullPath = path.resolve(__dirname, '../../', dir);
 
   bench.start();
@@ -18,11 +19,12 @@ async function main({ n, dir, mode }) {
   let counter = 0;
   for (let i = 0; i < n; i++) {
     if (mode === 'async') {
+      const dir = await fs.promises.opendir(fullPath, { bufferSize });
       // eslint-disable-next-line no-unused-vars
-      for await (const entry of await fs.promises.opendir(fullPath))
+      for await (const entry of dir)
         counter++;
     } else if (mode === 'callback') {
-      const dir = await fs.promises.opendir(fullPath);
+      const dir = await fs.promises.opendir(fullPath, { bufferSize });
       await new Promise((resolve, reject) => {
         function read() {
           dir.read((err, entry) => {
@@ -40,7 +42,7 @@ async function main({ n, dir, mode }) {
         read();
       });
     } else {
-      const dir = fs.opendirSync(fullPath);
+      const dir = fs.opendirSync(fullPath, { bufferSize });
       while (dir.readSync() !== null)
         counter++;
       dir.closeSync();