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, 13 insertions, 3 deletions

diff --git a/lib/internal/fs/dir.js b/lib/internal/fs/dir.js
index fedd7ff8ed..90ab31fe5a 100644
--- a/lib/internal/fs/dir.js
+++ b/lib/internal/fs/dir.js
@@ -21,6 +21,9 @@ const {
   getValidatedPath,
   handleErrorFromBinding
 } = require('internal/fs/utils');
+const {
+  validateUint32
+} = require('internal/validators');
 
 const kDirHandle = Symbol('kDirHandle');
 const kDirPath = Symbol('kDirPath');
@@ -39,9 +42,14 @@ class Dir {
     this[kDirPath] = path;
     this[kDirClosed] = false;
 
-    this[kDirOptions] = getOptions(options, {
-      encoding: 'utf8'
-    });
+    this[kDirOptions] = {
+      bufferSize: 32,
+      ...getOptions(options, {
+        encoding: 'utf8'
+      })
+    };
+
+    validateUint32(this[kDirOptions].bufferSize, 'options.bufferSize', true);
 
     this[kDirReadPromisified] =
         internalUtil.promisify(this[kDirReadImpl]).bind(this, false);
@@ -88,6 +96,7 @@ class Dir {
 
     this[kDirHandle].read(
       this[kDirOptions].encoding,
+      this[kDirOptions].bufferSize,
       req
     );
   }
@@ -105,6 +114,7 @@ class Dir {
     const ctx = { path: this[kDirPath] };
     const result = this[kDirHandle].read(
       this[kDirOptions].encoding,
+      this[kDirOptions].bufferSize,
       undefined,
       ctx
     );