feat: add ArrayBuffer::was_detached() (denoland#1103)

src/array_buffer.rs

@@ -38,6 +38,7 @@ extern "C" {
  fn v8__ArrayBuffer__Detach(this: *const ArrayBuffer);
  fn v8__ArrayBuffer__Data(this: *const ArrayBuffer) -> *mut c_void;
  fn v8__ArrayBuffer__IsDetachable(this: *const ArrayBuffer) -> bool;
+ fn v8__ArrayBuffer__WasDetached(this: *const ArrayBuffer) -> bool;
  fn v8__ArrayBuffer__ByteLength(this: *const ArrayBuffer) -> usize;
  fn v8__ArrayBuffer__GetBackingStore(
  this: *const ArrayBuffer,
@@ -389,6 +390,15 @@ impl ArrayBuffer {
  unsafe { v8__ArrayBuffer__IsDetachable(self) }
  }
 
+ /// Returns true if this ArrayBuffer was detached.
+ #[inline(always)]
+ pub fn was_detached(&self) -> bool {
+ if self.byte_length() != 0 {
+ return false;
+ }
+ unsafe { v8__ArrayBuffer__WasDetached(self) }
+ }
+
  /// Detaches this ArrayBuffer and all its views (typed arrays).
  /// Detaching sets the byte length of the buffer and all typed arrays to zero,
  /// preventing JavaScript from ever accessing underlying backing store.

src/binding.cc

@@ -828,6 +828,10 @@ bool v8__ArrayBuffer__IsDetachable(const v8::ArrayBuffer& self) {
  return ptr_to_local(&self)->IsDetachable();
 }
 
+bool v8__ArrayBuffer__WasDetached(const v8::ArrayBuffer& self) {
+ return v8::Utils::OpenHandle(&self)->was_detached();
+}
+
 void* v8__BackingStore__Data(const v8::BackingStore& self) {
  return self.Data();
 }

tests/test_api.rs

@@ -573,12 +573,20 @@ fn array_buffer() {
 
  let ab = v8::ArrayBuffer::new(scope, 42);
  assert_eq!(42, ab.byte_length());
-
+ assert!(!ab.was_detached());
  assert!(ab.is_detachable());
+
  ab.detach();
  assert_eq!(0, ab.byte_length());
+ assert!(ab.was_detached());
  ab.detach(); // Calling it twice should be a no-op.
 
+ // detecting if it was detached on a zero-length ArrayBuffer should work
+ let empty_ab = v8::ArrayBuffer::new(scope, 0);
+ assert!(!empty_ab.was_detached());
+ empty_ab.detach();
+ assert!(empty_ab.was_detached());
+
  let bs = v8::ArrayBuffer::new_backing_store(scope, 84);
  assert_eq!(84, bs.byte_length());
  assert!(!bs.is_shared());