2 files changed, 58 insertions, 0 deletions
diff --git a/serde_v8/magic/external_pointer.rs b/serde_v8/magic/external_pointer.rs
new file mode 100644
index 000000000..fca6028d6
--- /dev/null
+++ b/serde_v8/magic/external_pointer.rs
@@ -0,0 +1,56 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
+use std::ffi::c_void;
+
+use super::transl8::impl_magic;
+use super::transl8::FromV8;
+use super::transl8::ToV8;
+
+pub struct ExternalPointer(*mut c_void);
+
+// SAFETY: Nonblocking FFI is user controller and we must trust user to have it right.
+unsafe impl Send for ExternalPointer {}
+// SAFETY: Nonblocking FFI is user controller and we must trust user to have it right.
+unsafe impl Sync for ExternalPointer {}
+
+impl_magic!(ExternalPointer);
+
+impl ToV8 for ExternalPointer {
+  fn to_v8<'a>(
+    &mut self,
+    scope: &mut v8::HandleScope<'a>,
+  ) -> Result<v8::Local<'a, v8::Value>, crate::Error> {
+    if self.0.is_null() {
+      Ok(v8::null(scope).into())
+    } else {
+      Ok(v8::External::new(scope, self.0).into())
+    }
+  }
+}
+
+impl FromV8 for ExternalPointer {
+  fn from_v8(
+    _scope: &mut v8::HandleScope,
+    value: v8::Local<v8::Value>,
+  ) -> Result<Self, crate::Error> {
+    if value.is_null() {
+      Ok(ExternalPointer(std::ptr::null_mut()))
+    } else if let Ok(external) = v8::Local::<v8::External>::try_from(value) {
+      Ok(ExternalPointer(external.value()))
+    } else {
+      Err(crate::Error::ExpectedExternal)
+    }
+  }
+}
+
+impl From<*mut c_void> for ExternalPointer {
+  fn from(value: *mut c_void) -> Self {
+    ExternalPointer(value)
+  }
+}
+
+impl From<*const c_void> for ExternalPointer {
+  fn from(value: *const c_void) -> Self {
+    ExternalPointer(value as *mut c_void)
+  }
+}
diff --git a/serde_v8/magic/mod.rs b/serde_v8/magic/mod.rs
index fe4577672..f96e422b1 100644
--- a/serde_v8/magic/mod.rs
+++ b/serde_v8/magic/mod.rs
@@ -2,6 +2,7 @@
 pub mod buffer;
 pub mod bytestring;
 pub mod detached_buffer;
+mod external_pointer;
 mod global;
 pub(super) mod rawbytes;
 pub mod string_or_buffer;
@@ -9,5 +10,6 @@ pub mod transl8;
 pub mod u16string;
 pub mod v8slice;
 mod value;
+pub use external_pointer::ExternalPointer;
 pub use global::Global;
 pub use value::Value;