implement Rawable for all TypedArray types (#1679)

src/array_buffer.rs

@@ -253,26 +253,66 @@ pub type BackingStoreDeleterCallback = unsafe extern "C" fn(
 );
 
 pub(crate) mod sealed {
-  pub trait Rawable<T: ?Sized> {
+  pub trait Rawable {
+    fn byte_len(&mut self) -> usize;
     fn into_raw(self) -> (*const (), *const u8);
     unsafe fn drop_raw(ptr: *const (), size: usize);
   }
 }
 
-impl sealed::Rawable<[u8]> for Vec<u8> {
+macro_rules! rawable {
+  ($ty:ty) => {
+    impl sealed::Rawable for Box<[$ty]> {
+      fn byte_len(&mut self) -> usize {
+        self.as_mut().len() * std::mem::size_of::<$ty>()
+      }
+
+      fn into_raw(mut self) -> (*const (), *const u8) {
+        // Thin the fat pointer
+        let ptr = self.as_mut_ptr();
+        std::mem::forget(self);
+        (ptr as _, ptr as _)
+      }
+
+      unsafe fn drop_raw(ptr: *const (), len: usize) {
+        // Fatten the thin pointer
+        _ = Self::from_raw(std::ptr::slice_from_raw_parts_mut(ptr as _, len));
+      }
+    }
+
+    impl sealed::Rawable for Vec<$ty> {
+      fn byte_len(&mut self) -> usize {
+        Vec::<$ty>::len(self) * std::mem::size_of::<$ty>()
+      }
+
       unsafe fn drop_raw(ptr: *const (), size: usize) {
-    <Box<[u8]> as sealed::Rawable<[u8]>>::drop_raw(ptr, size);
+        <Box<[$ty]> as sealed::Rawable>::drop_raw(ptr, size);
       }
 
       fn into_raw(self) -> (*const (), *const u8) {
         self.into_boxed_slice().into_raw()
       }
     }
+  };
+}
 
-impl<T: Sized> sealed::Rawable<T> for Box<T>
+rawable!(u8);
+rawable!(u16);
+rawable!(u32);
+rawable!(u64);
+rawable!(i8);
+rawable!(i16);
+rawable!(i32);
+rawable!(i64);
+
+impl<T: Sized> sealed::Rawable for Box<T>
 where
   T: AsMut<[u8]>,
 {
+  fn byte_len(&mut self) -> usize {
+    self.as_mut().as_mut().len()
+  }
+
   fn into_raw(mut self) -> (*const (), *const u8) {
     let data = self.as_mut().as_mut().as_mut_ptr();
     let ptr = Self::into_raw(self);
@@ -284,20 +324,6 @@ where
   }
 }
 
-impl sealed::Rawable<[u8]> for Box<[u8]> {
-  fn into_raw(mut self) -> (*const (), *const u8) {
-    // Thin the fat pointer
-    let ptr = self.as_mut_ptr();
-    std::mem::forget(self);
-    (ptr as _, ptr)
-  }
-
-  unsafe fn drop_raw(ptr: *const (), len: usize) {
-    // Fatten the thin pointer
-    _ = Self::from_raw(std::ptr::slice_from_raw_parts_mut(ptr as _, len));
-  }
-}
-
 /// A wrapper around the backing store (i.e. the raw memory) of an array buffer.
 /// See a document linked in http://crbug.com/v8/9908 for more information.
 ///
@@ -565,16 +591,13 @@ impl ArrayBuffer {
   /// let backing_store = v8::ArrayBuffer::new_backing_store_from_bytes(Box::new(bytes::BytesMut::new()));
   /// ```
   #[inline(always)]
-  pub fn new_backing_store_from_bytes<T, U>(
+  pub fn new_backing_store_from_bytes<T>(
     mut bytes: T,
   ) -> UniqueRef<BackingStore>
   where
-    U: ?Sized,
-    U: AsMut<[u8]>,
-    T: AsMut<U>,
-    T: sealed::Rawable<U>,
+    T: sealed::Rawable,
   {
-    let len = bytes.as_mut().as_mut().len();
+    let len = bytes.byte_len();
     if len == 0 {
       return unsafe {
         UniqueRef::from_raw(v8__BackingStore__EmptyBackingStore(false))
@@ -583,13 +606,13 @@ impl ArrayBuffer {
 
     let (ptr, slice) = T::into_raw(bytes);
 
-    extern "C" fn drop_rawable<T: sealed::Rawable<U>, U: ?Sized>(
+    extern "C" fn drop_rawable<T: sealed::Rawable>(
       _ptr: *mut c_void,
       len: usize,
       data: *mut c_void,
     ) {
       // SAFETY: We know that data is a raw T from above
-      unsafe { <T as sealed::Rawable<U>>::drop_raw(data as _, len) }
+      unsafe { T::drop_raw(data as _, len) }
     }
 
     // SAFETY: We are extending the lifetime of a slice, but we're locking away the box that we
@@ -598,7 +621,7 @@ impl ArrayBuffer {
       Self::new_backing_store_from_ptr(
         slice as _,
         len,
-        drop_rawable::<T, U>,
+        drop_rawable::<T>,
         ptr as _,
       )
     }

src/shared_array_buffer.rs

@@ -166,16 +166,13 @@ impl SharedArrayBuffer {
   /// let backing_store = v8::ArrayBuffer::new_backing_store_from_bytes(Box::new(bytes::BytesMut::new()));
   /// ```
   #[inline(always)]
-  pub fn new_backing_store_from_bytes<T, U>(
+  pub fn new_backing_store_from_bytes<T>(
     mut bytes: T,
   ) -> UniqueRef<BackingStore>
   where
-    U: ?Sized,
-    U: AsMut<[u8]>,
-    T: AsMut<U>,
-    T: crate::array_buffer::sealed::Rawable<U>,
+    T: crate::array_buffer::sealed::Rawable,
   {
-    let len = bytes.as_mut().as_mut().len();
+    let len = bytes.byte_len();
     if len == 0 {
       return unsafe {
         UniqueRef::from_raw(v8__BackingStore__EmptyBackingStore(false))
@@ -184,17 +181,14 @@ impl SharedArrayBuffer {
 
     let (ptr, slice) = T::into_raw(bytes);
 
-    extern "C" fn drop_rawable<
-      T: crate::array_buffer::sealed::Rawable<U>,
-      U: ?Sized,
-    >(
+    extern "C" fn drop_rawable<T: crate::array_buffer::sealed::Rawable>(
       _ptr: *mut c_void,
       len: usize,
       data: *mut c_void,
     ) {
       // SAFETY: We know that data is a raw T from above
       unsafe {
-        <T as crate::array_buffer::sealed::Rawable<U>>::drop_raw(data as _, len)
+        <T as crate::array_buffer::sealed::Rawable>::drop_raw(data as _, len)
       }
     }
 
@@ -204,7 +198,7 @@ impl SharedArrayBuffer {
       Self::new_backing_store_from_ptr(
         slice as _,
         len,
-        drop_rawable::<T, U>,
+        drop_rawable::<T>,
         ptr as _,
       )
     }

tests/test_api.rs

@@ -862,13 +862,14 @@ fn array_buffer() {
     // Empty but from vec
     let ab = v8::ArrayBuffer::with_backing_store(
       scope,
-      &v8::ArrayBuffer::new_backing_store_from_bytes(vec![]).make_shared(),
+      &v8::ArrayBuffer::new_backing_store_from_bytes(Vec::<u8>::new())
+        .make_shared(),
     );
     assert_eq!(0, ab.byte_length());
     assert!(!ab.get_backing_store().is_shared());
 
     // Empty but from vec with a huge capacity
-    let mut v = Vec::with_capacity(10_000_000);
+    let mut v: Vec<u8> = Vec::with_capacity(10_000_000);
     v.extend_from_slice(&[1, 2, 3, 4]);
     let ab = v8::ArrayBuffer::with_backing_store(
       scope,