fastcall: Fix get_storage_if_aligned for non-uint8arrays (denoland#…

…1077)

src/fast_api.rs

@@ -192,7 +192,8 @@ pub struct FastApiCallbackOptions<'a> {
 // https://source.chromium.org/chromium/chromium/src/+/main:v8/include/v8-fast-api-calls.h;l=336
 #[repr(C)]
 pub struct FastApiTypedArray<T: Default> {
- pub byte_length: usize,
+ /// Returns the length in number of elements.
+ pub length: usize,
  // This pointer should include the typed array offset applied.
  // It's not guaranteed that it's aligned to sizeof(T), it's only
  // guaranteed that it's 4-byte aligned, so for 8-byte types we need to
@@ -204,7 +205,7 @@ pub struct FastApiTypedArray<T: Default> {
 impl<T: Default> FastApiTypedArray<T> {
  #[inline]
  pub fn get(&self, index: usize) -> T {
- debug_assert!(index < self.byte_length);
+ debug_assert!(index < self.length);
  let mut t: T = Default::default();
  unsafe {
  ptr::copy_nonoverlapping(self.data.add(index), &mut t, 1);
@@ -217,12 +218,7 @@ impl<T: Default> FastApiTypedArray<T> {
  if (self.data as usize) % align_of::<T>() != 0 {
  return None;
  }
- Some(unsafe {
- std::slice::from_raw_parts_mut(
- self.data,
- self.byte_length / align_of::<T>(),
- )
- })
+ Some(unsafe { std::slice::from_raw_parts_mut(self.data, self.length) })
  }
 }
 

tests/test_api.rs

@@ -7560,7 +7560,7 @@ fn test_fast_calls_overload() {
  ) {
  unsafe { WHO = "fast_buf" };
  let buf = unsafe { &*data };
- assert_eq!(buf.byte_length, 2);
+ assert_eq!(buf.length, 2);
  assert_eq!(buf.get(0), 6);
  assert_eq!(buf.get(1), 9);
  }