worker,fs: make FileHandle transferable

Allow passing `FileHandle` instances in the transfer list
of a `.postMessage()` call.

PR-URL: https://github.com/nodejs/node/pull/33772
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>

1 files changed, 34 insertions, 0 deletions

diff --git a/src/node_file.cc b/src/node_file.cc
index c2ed56f43fb..9ed2d2960cf 100644
--- a/src/node_file.cc
+++ b/src/node_file.cc
@@ -190,6 +190,40 @@ void FileHandle::MemoryInfo(MemoryTracker* tracker) const {
   tracker->TrackField("current_read", current_read_);
 }
 
+FileHandle::TransferMode FileHandle::GetTransferMode() const {
+  return reading_ || closing_ || closed_ ?
+      TransferMode::kUntransferable : TransferMode::kTransferable;
+}
+
+std::unique_ptr<worker::TransferData> FileHandle::TransferForMessaging() {
+  CHECK_NE(GetTransferMode(), TransferMode::kUntransferable);
+  auto ret = std::make_unique<TransferData>(fd_);
+  closed_ = true;
+  return ret;
+}
+
+FileHandle::TransferData::TransferData(int fd) : fd_(fd) {}
+
+FileHandle::TransferData::~TransferData() {
+  if (fd_ > 0) {
+    uv_fs_t close_req;
+    CHECK_EQ(0, uv_fs_close(nullptr, &close_req, fd_, nullptr));
+    uv_fs_req_cleanup(&close_req);
+  }
+}
+
+BaseObjectPtr<BaseObject> FileHandle::TransferData::Deserialize(
+    Environment* env,
+    v8::Local<v8::Context> context,
+    std::unique_ptr<worker::TransferData> self) {
+  BindingData* bd = Environment::GetBindingData<BindingData>(context);
+  if (bd == nullptr) return {};
+
+  int fd = fd_;
+  fd_ = -1;
+  return BaseObjectPtr<BaseObject> { FileHandle::New(bd, fd) };
+}
+
 // Close the file descriptor if it hasn't already been closed. A process
 // warning will be emitted using a SetImmediate to avoid calling back to
 // JS during GC. If closing the fd fails at this point, a fatal exception