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, 18 insertions, 8 deletions

diff --git a/src/node_dir.cc b/src/node_dir.cc
index 382f00f56e..ffef27f452 100644
--- a/src/node_dir.cc
+++ b/src/node_dir.cc
@@ -36,6 +36,7 @@ using v8::Isolate;
 using v8::Local;
 using v8::MaybeLocal;
 using v8::Null;
+using v8::Number;
 using v8::Object;
 using v8::ObjectTemplate;
 using v8::String;
@@ -59,8 +60,8 @@ DirHandle::DirHandle(Environment* env, Local<Object> obj, uv_dir_t* dir)
       dir_(dir) {
   MakeWeak();
 
-  dir_->nentries = arraysize(dirents_);
-  dir_->dirents = dirents_;
+  dir_->nentries = 0;
+  dir_->dirents = nullptr;
 }
 
 DirHandle* DirHandle::New(Environment* env, uv_dir_t* dir) {
@@ -230,22 +231,31 @@ void DirHandle::Read(const FunctionCallbackInfo<Value>& args) {
   Isolate* isolate = env->isolate();
 
   const int argc = args.Length();
-  CHECK_GE(argc, 2);
+  CHECK_GE(argc, 3);
 
   const enum encoding encoding = ParseEncoding(isolate, args[0], UTF8);
 
   DirHandle* dir;
   ASSIGN_OR_RETURN_UNWRAP(&dir, args.Holder());
 
-  FSReqBase* req_wrap_async = GetReqWrap(env, args[1]);
-  if (req_wrap_async != nullptr) {  // dir.read(encoding, req)
+  CHECK(args[1]->IsNumber());
+  uint64_t buffer_size = args[1].As<Number>()->Value();
+
+  if (buffer_size != dir->dirents_.size()) {
+    dir->dirents_.resize(buffer_size);
+    dir->dir_->nentries = buffer_size;
+    dir->dir_->dirents = dir->dirents_.data();
+  }
+
+  FSReqBase* req_wrap_async = GetReqWrap(env, args[2]);
+  if (req_wrap_async != nullptr) {  // dir.read(encoding, bufferSize, req)
     AsyncCall(env, req_wrap_async, args, "readdir", encoding,
               AfterDirRead, uv_fs_readdir, dir->dir());
-  } else {  // dir.read(encoding, undefined, ctx)
-    CHECK_EQ(argc, 3);
+  } else {  // dir.read(encoding, bufferSize, undefined, ctx)
+    CHECK_EQ(argc, 4);
     FSReqWrapSync req_wrap_sync;
     FS_DIR_SYNC_TRACE_BEGIN(readdir);
-    int err = SyncCall(env, args[2], &req_wrap_sync, "readdir", uv_fs_readdir,
+    int err = SyncCall(env, args[3], &req_wrap_sync, "readdir", uv_fs_readdir,
                        dir->dir());
     FS_DIR_SYNC_TRACE_END(readdir);
     if (err < 0) {