Implement non-erased JsObjects (#3618)

core/engine/src/builtins/array_buffer/mod.rs

@@ -207,7 +207,9 @@ impl BuiltInConstructor for ArrayBuffer {
         let byte_length = args.get_or_undefined(0).to_index(context)?;
 
         // 3. Return ? AllocateArrayBuffer(NewTarget, byteLength).
-        Ok(Self::allocate(new_target, byte_length, context)?.into())
+        Ok(Self::allocate(new_target, byte_length, context)?
+            .upcast()
+            .into())
     }
 }
 
@@ -384,7 +386,7 @@ impl ArrayBuffer {
         constructor: &JsValue,
         byte_length: u64,
         context: &mut Context,
-    ) -> JsResult<JsObject> {
+    ) -> JsResult<JsObject<ArrayBuffer>> {
         // 1. Let obj be ? OrdinaryCreateFromConstructor(constructor, "%ArrayBuffer.prototype%", « [[ArrayBufferData]], [[ArrayBufferByteLength]], [[ArrayBufferDetachKey]] »).
         let prototype = get_prototype_from_constructor(
             constructor,
@@ -397,7 +399,7 @@ impl ArrayBuffer {
 
         // 3. Set obj.[[ArrayBufferData]] to block.
         // 4. Set obj.[[ArrayBufferByteLength]] to byteLength.
-        let obj = JsObject::from_proto_and_data_with_shared_shape(
+        let obj = JsObject::new(
             context.root_shape(),
             prototype,
             Self {

core/engine/src/builtins/array_buffer/utils.rs

@@ -120,7 +120,7 @@ impl SliceRef<'_> {
     ///  - [ECMAScript reference][spec]
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-clonearraybuffer
-    pub(crate) fn clone(&self, context: &mut Context) -> JsResult<JsObject> {
+    pub(crate) fn clone(&self, context: &mut Context) -> JsResult<JsObject<ArrayBuffer>> {
         // 1. Assert: IsDetachedBuffer(srcBuffer) is false.
 
         // 2. Let targetBuffer be ? AllocateArrayBuffer(%ArrayBuffer%, srcLength).
@@ -140,12 +140,10 @@ impl SliceRef<'_> {
 
         // 4. Let targetBlock be targetBuffer.[[ArrayBufferData]].
         {
-            let mut target_buffer = target_buffer
-                .downcast_mut::<ArrayBuffer>()
-                .expect("This must be an ArrayBuffer");
+            let mut target_buffer = target_buffer.borrow_mut();
             let target_block = target_buffer
                 .data
-                .as_deref_mut()
+                .data_mut()
                 .expect("ArrayBuffer cannot be detached here");
 
             // 5. Perform CopyDataBlockBytes(targetBlock, 0, srcBlock, srcByteOffset, srcLength).

core/engine/src/builtins/typed_array/builtin.rs

@@ -2096,7 +2096,8 @@ impl BuiltinTypedArray {
                     .subslice(src_byte_offset..src_byte_offset + src_byte_length)
                     .clone(context)?
             };
-            src_buffer_obj = s;
+            // TODO: skip this upcast
+            src_buffer_obj = s.upcast();
 
             // d. Let srcByteIndex be 0.
             0
@@ -3068,7 +3069,14 @@ impl BuiltinTypedArray {
         // 9. Set O.[[ArrayLength]] to length.
 
         // 10. Return O.
-        Ok(TypedArray::new(data, T::ERASED, 0, byte_length, length))
+        // TODO: skip this upcast.
+        Ok(TypedArray::new(
+            data.upcast(),
+            T::ERASED,
+            0,
+            byte_length,
+            length,
+        ))
     }
 
     /// <https://tc39.es/ecma262/#sec-initializetypedarrayfromlist>
@@ -3209,11 +3217,12 @@ impl BuiltinTypedArray {
                 context,
             )?;
             {
-                let mut data = data_obj
-                    .downcast_mut::<ArrayBuffer>()
-                    .expect("Must be ArrayBuffer");
-                let mut data =
-                    SliceRefMut::Slice(data.data_mut().expect("a new buffer cannot be detached"));
+                let mut data = data_obj.borrow_mut();
+                let mut data = SliceRefMut::Slice(
+                    data.data
+                        .data_mut()
+                        .expect("a new buffer cannot be detached"),
+                );
 
                 // b. If srcArray.[[ContentType]] is not O.[[ContentType]], throw a TypeError exception.
                 if src_type.content_type() != element_type.content_type() {
@@ -3279,10 +3288,17 @@ impl BuiltinTypedArray {
         // 13. Set O.[[ByteLength]] to byteLength.
         // 14. Set O.[[ByteOffset]] to 0.
         // 15. Set O.[[ArrayLength]] to elementLength.
+        // TODO: Skip this upcast.
         let obj = JsObject::from_proto_and_data_with_shared_shape(
             context.root_shape(),
             proto,
-            TypedArray::new(new_buffer, element_type, 0, byte_length, element_length),
+            TypedArray::new(
+                new_buffer.upcast(),
+                element_type,
+                0,
+                byte_length,
+                element_length,
+            ),
         );
 
         // 16. Return unused.

core/engine/src/object/builtins/jsarraybuffer.rs

@@ -3,9 +3,7 @@ use crate::{
     builtins::array_buffer::ArrayBuffer,
     context::intrinsics::StandardConstructors,
     error::JsNativeError,
-    object::{
-        internal_methods::get_prototype_from_constructor, ErasedObject, JsObject, JsObjectType,
-    },
+    object::{internal_methods::get_prototype_from_constructor, JsObject, JsObjectType, Object},
     value::TryFromJs,
     Context, JsResult, JsValue,
 };
@@ -14,8 +12,9 @@ use std::ops::Deref;
 
 /// `JsArrayBuffer` provides a wrapper for Boa's implementation of the ECMAScript `ArrayBuffer` object
 #[derive(Debug, Clone, Trace, Finalize)]
+#[boa_gc(unsafe_no_drop)]
 pub struct JsArrayBuffer {
-    inner: JsObject,
+    inner: JsObject<ArrayBuffer>,
 }
 
 // TODO: Add constructors that also take the `detach_key` as argument.
@@ -103,7 +102,7 @@ impl JsArrayBuffer {
 
         // 3. Set obj.[[ArrayBufferData]] to block.
         // 4. Set obj.[[ArrayBufferByteLength]] to byteLength.
-        let obj = JsObject::from_proto_and_data_with_shared_shape(
+        let obj = JsObject::new(
             context.root_shape(),
             prototype,
             ArrayBuffer::from_data(block, JsValue::Undefined),
@@ -117,13 +116,14 @@ impl JsArrayBuffer {
     /// This does not clone the fields of the array buffer, it only does a shallow clone of the object.
     #[inline]
     pub fn from_object(object: JsObject) -> JsResult<Self> {
-        if object.is::<ArrayBuffer>() {
-            Ok(Self { inner: object })
-        } else {
-            Err(JsNativeError::typ()
-                .with_message("object is not an ArrayBuffer")
-                .into())
-        }
+        object
+            .downcast::<ArrayBuffer>()
+            .map(|inner| Self { inner })
+            .map_err(|_| {
+                JsNativeError::typ()
+                    .with_message("object is not an ArrayBuffer")
+                    .into()
+            })
     }
 
     /// Returns the byte length of the array buffer.
@@ -141,18 +141,16 @@ impl JsArrayBuffer {
     /// let array_buffer = JsArrayBuffer::from_byte_block(data_block, context)?;
     ///
     /// // Take the inner buffer
-    /// let buffer_length = array_buffer.byte_length(context);
+    /// let buffer_length = array_buffer.byte_length();
     ///
     /// assert_eq!(buffer_length, 5);
     /// # Ok(())
     /// # }
     ///  ```
     #[inline]
-    pub fn byte_length(&self, context: &mut Context) -> usize {
-        ArrayBuffer::get_byte_length(&self.inner.clone().into(), &[], context)
-            .expect("it should not throw")
-            .as_number()
-            .expect("expected a number") as usize
+    #[must_use]
+    pub fn byte_length(&self) -> usize {
+        self.inner.borrow().data.len()
     }
 
     /// Take the inner `ArrayBuffer`'s `array_buffer_data` field and replace it with `None`
@@ -188,8 +186,8 @@ impl JsArrayBuffer {
     #[inline]
     pub fn detach(&self, detach_key: &JsValue) -> JsResult<Vec<u8>> {
         self.inner
-            .downcast_mut::<ArrayBuffer>()
-            .expect("inner must be an ArrayBuffer")
+            .borrow_mut()
+            .data
             .detach(detach_key)?
             .ok_or_else(|| {
                 JsNativeError::typ()
@@ -224,12 +222,7 @@ impl JsArrayBuffer {
     #[inline]
     #[must_use]
     pub fn data(&self) -> Option<GcRef<'_, [u8]>> {
-        debug_assert!(
-            self.inner.is::<ArrayBuffer>(),
-            "inner must be an ArrayBuffer"
-        );
-
-        GcRef::try_map(self.inner.downcast_ref::<ArrayBuffer>()?, ArrayBuffer::data)
+        GcRef::try_map(self.inner.borrow(), |o| o.data.data())
     }
 
     /// Get a mutable reference to the [`JsArrayBuffer`]'s data.
@@ -261,35 +254,27 @@ impl JsArrayBuffer {
     /// ```
     #[inline]
     #[must_use]
-    pub fn data_mut(&self) -> Option<GcRefMut<'_, ErasedObject, [u8]>> {
-        debug_assert!(
-            self.inner.is::<ArrayBuffer>(),
-            "inner must be an ArrayBuffer"
-        );
-
-        GcRefMut::try_map(
-            self.inner.downcast_mut::<ArrayBuffer>()?,
-            ArrayBuffer::data_mut,
-        )
+    pub fn data_mut(&self) -> Option<GcRefMut<'_, Object<ArrayBuffer>, [u8]>> {
+        GcRefMut::try_map(self.inner.borrow_mut(), |o| o.data.data_mut())
     }
 }
 
 impl From<JsArrayBuffer> for JsObject {
     #[inline]
     fn from(o: JsArrayBuffer) -> Self {
-        o.inner.clone()
+        o.inner.upcast()
     }
 }
 
 impl From<JsArrayBuffer> for JsValue {
     #[inline]
     fn from(o: JsArrayBuffer) -> Self {
-        o.inner.clone().into()
+        o.inner.upcast().into()
     }
 }
 
 impl Deref for JsArrayBuffer {
-    type Target = JsObject;
+    type Target = JsObject<ArrayBuffer>;
 
     #[inline]
     fn deref(&self) -> &Self::Target {

core/engine/src/object/builtins/jsdataview.rs

@@ -1,6 +1,6 @@
 //! A Rust API wrapper for Boa's `DataView` Builtin ECMAScript Object
 use crate::{
-    builtins::{array_buffer::ArrayBuffer, DataView},
+    builtins::DataView,
     context::intrinsics::StandardConstructors,
     object::{
         internal_methods::get_prototype_from_constructor, JsArrayBuffer, JsObject, JsObjectType,
@@ -27,7 +27,7 @@ use std::ops::Deref;
 ///
 /// // Create a new Dataview from pre-existing ArrayBuffer
 /// let data_view =
-///     JsDataView::from_js_array_buffer(&array_buffer, None, None, context)?;
+///     JsDataView::from_js_array_buffer(array_buffer, None, None, context)?;
 ///
 /// # Ok(())
 /// # }
@@ -40,26 +40,23 @@ pub struct JsDataView {
 impl JsDataView {
     /// Create a new `JsDataView` object from an existing `JsArrayBuffer`.
     pub fn from_js_array_buffer(
-        array_buffer: &JsArrayBuffer,
+        array_buffer: JsArrayBuffer,
         offset: Option<u64>,
         byte_length: Option<u64>,
         context: &mut Context,
     ) -> JsResult<Self> {
         let (byte_offset, byte_length) = {
-            let buffer = array_buffer.downcast_ref::<ArrayBuffer>().ok_or_else(|| {
-                JsNativeError::typ().with_message("buffer must be an ArrayBuffer")
-            })?;
-
+            let buffer = array_buffer.borrow();
             let provided_offset = offset.unwrap_or(0_u64);
 
             // Check if buffer is detached.
-            if buffer.is_detached() {
+            if buffer.data.is_detached() {
                 return Err(JsNativeError::typ()
                     .with_message("ArrayBuffer is detached")
                     .into());
             };
 
-            let array_buffer_length = buffer.len() as u64;
+            let array_buffer_length = buffer.data.len() as u64;
 
             if provided_offset > array_buffer_length {
                 return Err(JsNativeError::range()
@@ -97,7 +94,8 @@ impl JsDataView {
             context.root_shape(),
             prototype,
             DataView {
-                viewed_array_buffer: (**array_buffer).clone(),
+                // TODO: Remove upcast.
+                viewed_array_buffer: array_buffer.into(),
                 byte_length,
                 byte_offset,
             },

core/engine/src/object/internal_methods/mod.rs

@@ -1043,7 +1043,7 @@ where
     Ok(default(realm.intrinsics().constructors()).prototype())
 }
 
-pub(crate) fn non_existant_call(
+fn non_existant_call(
     _obj: &JsObject,
     _argument_count: usize,
     context: &mut Context,
@@ -1054,7 +1054,7 @@ pub(crate) fn non_existant_call(
         .into())
 }
 
-pub(crate) fn non_existant_construct(
+fn non_existant_construct(
     _obj: &JsObject,
     _argument_count: usize,
     context: &mut Context,