perf(serde_v8): `serde_v8::StringOrBuffer` return JS ArrayBuffer instead of Uint8Array (#16360)

Towards #16315

1 files changed, 18 insertions, 1 deletions

diff --git a/serde_v8/magic/string_or_buffer.rs b/serde_v8/magic/string_or_buffer.rs
index aa7e26d2b..582314d4b 100644
--- a/serde_v8/magic/string_or_buffer.rs
+++ b/serde_v8/magic/string_or_buffer.rs
@@ -29,7 +29,24 @@ impl ToV8 for StringOrBuffer {
     scope: &mut v8::HandleScope<'a>,
   ) -> Result<v8::Local<'a, v8::Value>, crate::Error> {
     match self {
-      Self::Buffer(buf) => crate::to_v8(scope, buf),
+      Self::Buffer(buf) => {
+        let buf: Box<[u8]> = match buf {
+          ZeroCopyBuf::FromV8(buf) => {
+            let value: &[u8] = buf;
+            value.into()
+          }
+          ZeroCopyBuf::Temp(_) => unreachable!(),
+          ZeroCopyBuf::ToV8(ref mut x) => {
+            x.take().expect("ZeroCopyBuf was empty")
+          }
+        };
+        let backing_store =
+          v8::ArrayBuffer::new_backing_store_from_boxed_slice(buf);
+        Ok(
+          v8::ArrayBuffer::with_backing_store(scope, &backing_store.into())
+            .into(),
+        )
+      }
       Self::String(s) => crate::to_v8(scope, s),
     }
   }