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, 21 insertions, 0 deletions

diff --git a/doc/api/fs.md b/doc/api/fs.md
index 78b7b3af2f..7f6c815b9b 100644
--- a/doc/api/fs.md
+++ b/doc/api/fs.md
@@ -2625,11 +2625,18 @@ Functions based on `fs.open()` exhibit this behavior as well:
 ## fs.opendir(path\[, options\], callback)
 <!-- YAML
 added: v12.12.0
+changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/30114
+    description: The `bufferSize` option was introduced.
 -->
 
 * `path` {string|Buffer|URL}
 * `options` {Object}
   * `encoding` {string|null} **Default:** `'utf8'`
+  * `bufferSize` {number} Number of directory entries that are buffered
+    internally when reading from the directory. Higher values lead to better
+    performance but higher memory usage. **Default:** `32`
 * `callback` {Function}
   * `err` {Error}
   * `dir` {fs.Dir}
@@ -2645,11 +2652,18 @@ directory and subsequent read operations.
 ## fs.opendirSync(path\[, options\])
 <!-- YAML
 added: v12.12.0
+changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/30114
+    description: The `bufferSize` option was introduced.
 -->
 
 * `path` {string|Buffer|URL}
 * `options` {Object}
   * `encoding` {string|null} **Default:** `'utf8'`
+  * `bufferSize` {number} Number of directory entries that are buffered
+    internally when reading from the directory. Higher values lead to better
+    performance but higher memory usage. **Default:** `32`
 * Returns: {fs.Dir}
 
 Synchronously open a directory. See opendir(3).
@@ -4829,11 +4843,18 @@ a colon, Node.js will open a file system stream, as described by
 ### fsPromises.opendir(path\[, options\])
 <!-- YAML
 added: v12.12.0
+changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/30114
+    description: The `bufferSize` option was introduced.
 -->
 
 * `path` {string|Buffer|URL}
 * `options` {Object}
   * `encoding` {string|null} **Default:** `'utf8'`
+  * `bufferSize` {number} Number of directory entries that are buffered
+    internally when reading from the directory. Higher values lead to better
+    performance but higher memory usage. **Default:** `32`
 * Returns: {Promise} containing {fs.Dir}
 
 Asynchronously open a directory. See opendir(3).