perf(ext/web): optimize transferArrayBuffer (#16294)

Avoid copying enqueued data + misc optimizations to skip webidl
converter.

1 files changed, 18 insertions, 0 deletions

diff --git a/ext/web/lib.rs b/ext/web/lib.rs
index 8a9d3e18c..588a3adfd 100644
--- a/ext/web/lib.rs
+++ b/ext/web/lib.rs
@@ -112,6 +112,7 @@ pub fn init<P: TimersPermission + 'static>(
       op_timer_handle::decl(),
       op_cancel_handle::decl(),
       op_sleep::decl(),
+      op_transfer_arraybuffer::decl(),
     ])
     .state(move |state| {
       state.put(blob_store.clone());
@@ -338,6 +339,23 @@ fn op_encoding_encode_into(
   Ok(())
 }
 
+#[op(v8)]
+fn op_transfer_arraybuffer<'a>(
+  scope: &mut v8::HandleScope<'a>,
+  input: serde_v8::Value<'a>,
+) -> Result<serde_v8::Value<'a>, AnyError> {
+  let ab = v8::Local::<v8::ArrayBuffer>::try_from(input.v8_value)?;
+  if !ab.is_detachable() {
+    return Err(type_error("ArrayBuffer is not detachable"));
+  }
+  let bs = ab.get_backing_store();
+  ab.detach();
+  let ab = v8::ArrayBuffer::with_backing_store(scope, &bs);
+  Ok(serde_v8::Value {
+    v8_value: ab.into(),
+  })
+}
+
 #[op]
 fn op_encode_binary_string(s: &[u8]) -> ByteString {
   ByteString::from(s)