fs: fix cpSync crash on utf characters

Author: jazelly

src/node_file.cc

@@ -3130,14 +3130,14 @@ static void CpSyncCheckPaths(const FunctionCallbackInfo<Value>& args) {
   ToNamespacedPath(env, &src);
   THROW_IF_INSUFFICIENT_PERMISSIONS(
       env, permission::PermissionScope::kFileSystemRead, src.ToStringView());
-  auto src_path = std::filesystem::path(src.ToStringView());
+  auto src_path = std::filesystem::path(src.ToStringU8View());
 
   BufferValue dest(isolate, args[1]);
   CHECK_NOT_NULL(*dest);
   ToNamespacedPath(env, &dest);
   THROW_IF_INSUFFICIENT_PERMISSIONS(
       env, permission::PermissionScope::kFileSystemWrite, dest.ToStringView());
-  auto dest_path = std::filesystem::path(dest.ToStringView());
+  auto dest_path = std::filesystem::path(dest.ToStringU8View());
 
   bool dereference = args[2]->IsTrue();
   bool recursive = args[3]->IsTrue();

src/util.h

@@ -562,6 +562,10 @@ class BufferValue : public MaybeStackBuffer<char> {
   inline std::string_view ToStringView() const {
     return std::string_view(out(), length());
   }
+  inline std::u8string_view ToStringU8View() const {
+    return std::u8string_view(reinterpret_cast<const char8_t*>(out()),
+                              length());
+  }
 };
 
 #define SPREAD_BUFFER_ARG(val, name)                                           \

test/fixtures/copy/utf/新建文件/index.js

@@ -0,0 +1,3 @@
+module.exports = {
+  purpose: 'testing copy'
+};

test/parallel/test-fs-cp.mjs

@@ -30,6 +30,14 @@ function nextdir() {
 
 // Synchronous implementation of copy.
 
+// It copies a nested folder containing UTF characters.
+{
+  const src = './test/fixtures/copy/utf/新建文件';
+  const dest = nextdir();
+  cpSync(src, dest, mustNotMutateObjectDeep({ recursive: true }));
+  assertDirEquivalent(src, dest);
+}
+
 // It copies a nested folder structure with files and folders.
 {
   const src = './test/fixtures/copy/kitchen-sink';