fixup! fs: buffer dir entries in opendir()

benchmark/fs/bench-opendir.js

@@ -10,26 +10,24 @@ const bench = common.createBenchmark(main, {
   mode: [ 'async', 'sync' ]
 });
 
-function main({ n, dir, mode }) {
+async function main({ n, dir, mode }) {
   const fullPath = path.resolve(__dirname, '../../', dir);
 
-  (async () => {
-    bench.start();
+  bench.start();
 
-    let counter = 0;
-    for (let i = 0; i < n; i++) {
-      if (mode === 'async') {
-        // eslint-disable-next-line no-unused-vars
-        for await (const entry of await fs.promises.opendir(fullPath))
-          counter++;
-      } else {
-        const dir = fs.opendirSync(fullPath);
-        while (dir.readSync() !== null)
-          counter++;
-        dir.closeSync();
-      }
+  let counter = 0;
+  for (let i = 0; i < n; i++) {
+    if (mode === 'async') {
+      // eslint-disable-next-line no-unused-vars
+      for await (const entry of await fs.promises.opendir(fullPath))
+        counter++;
+    } else {
+      const dir = fs.opendirSync(fullPath);
+      while (dir.readSync() !== null)
+        counter++;
+      dir.closeSync();
     }
+  }
 
-    bench.end(counter);
-  })();
+  bench.end(counter);
 }

lib/internal/fs/dir.js

@@ -27,6 +27,7 @@ const kDirPath = Symbol('kDirPath');
 const kDirBufferedEntries = Symbol('kDirBufferedEntries');
 const kDirClosed = Symbol('kDirClosed');
 const kDirOptions = Symbol('kDirOptions');
+const kDirReadImpl = Symbol('kDirReadImpl');
 const kDirReadPromisified = Symbol('kDirReadPromisified');
 const kDirClosePromisified = Symbol('kDirClosePromisified');
 
@@ -42,7 +43,7 @@ class Dir {
       encoding: 'utf8'
     });
 
-    this[kDirReadPromisified] = internalUtil.promisify(this.read).bind(this);
+    this[kDirReadPromisified] = internalUtil.promisify(this[kDirReadImpl]).bind(this, false);
     this[kDirClosePromisified] = internalUtil.promisify(this.close).bind(this);
   }
 
@@ -51,6 +52,10 @@ class Dir {
   }
 
   read(callback) {
+    return this[kDirReadImpl](true, callback);
+  }
+
+  [kDirReadImpl](maybeSync, callback) {
     if (this[kDirClosed] === true) {
       throw new ERR_DIR_CLOSED();
     }
@@ -63,7 +68,10 @@ class Dir {
 
     if (this[kDirBufferedEntries].length > 0) {
       const [ name, type ] = this[kDirBufferedEntries].splice(0, 2);
-      getDirent(this[kDirPath], name, type, callback);
+      if (maybeSync)
+        process.nextTick(getDirent, this[kDirPath], name, type, callback);
+      else
+        getDirent(this[kDirPath], name, type, callback);
       return;
     }
 

test/parallel/test-fs-opendir.js

@@ -58,17 +58,27 @@ const dirclosedError = {
 // Check the opendir async version
 fs.opendir(testDir, common.mustCall(function(err, dir) {
   assert.ifError(err);
-  dir.read(common.mustCall(function(err, dirent) {
+  let sync = true;
+  dir.read(common.mustCall((err, dirent) => {
+    assert(!sync);
     assert.ifError(err);
 
     // Order is operating / file system dependent
     assert(files.includes(dirent.name), `'files' should include ${dirent}`);
     assertDirent(dirent);
 
-    dir.close(common.mustCall(function(err) {
+    let syncInner = true;
+    dir.read(common.mustCall((err, dirent) => {
+      assert(!syncInner);
       assert.ifError(err);
+
+      dir.close(common.mustCall(function(err) {
+        assert.ifError(err);
+      }));
     }));
+    syncInner = false;
   }));
+  sync = false;
 }));
 
 // opendir() on file should throw ENOTDIR