feat(napi): implement add_finalizer for JsObject

napi/src/js_values/object.rs

@@ -1,13 +1,86 @@
-use super::Value;
-#[cfg(feature = "napi6")]
-use crate::sys;
-#[cfg(feature = "napi6")]
-use crate::{Error, Result};
 #[cfg(feature = "napi6")]
 use std::convert::TryFrom;
+#[cfg(feature = "napi5")]
+use std::ffi::c_void;
+#[cfg(feature = "napi5")]
+use std::ptr;
+
+#[cfg(feature = "napi5")]
+use super::check_status;
+use super::Value;
+#[cfg(feature = "napi5")]
+use crate::sys;
+#[cfg(feature = "napi5")]
+use crate::Env;
+#[cfg(feature = "napi6")]
+use crate::{Error, Result};
 
 pub struct JsObject(pub(crate) Value);
 
+#[cfg(feature = "napi5")]
+pub struct FinalizeContext<T: 'static, Hint: 'static> {
+  pub env: Env,
+  pub value: T,
+  pub hint: Hint,
+}
+
+#[cfg(feature = "napi5")]
+impl JsObject {
+  pub fn add_finalizer<T, Hint, F>(
+    &mut self,
+    native: T,
+    finalize_hint: Hint,
+    finalize_cb: F,
+  ) -> Result<()>
+  where
+    T: 'static,
+    Hint: 'static,
+    F: FnOnce(FinalizeContext<T, Hint>),
+  {
+    let mut maybe_ref = ptr::null_mut();
+    check_status!(unsafe {
+      sys::napi_add_finalizer(
+        self.0.env,
+        self.0.value,
+        Box::leak(Box::new((native, finalize_cb, maybe_ref))) as *mut _ as *mut c_void,
+        Some(
+          finalize_callback::<T, Hint, F>
+            as unsafe extern "C" fn(
+              env: sys::napi_env,
+              finalize_data: *mut c_void,
+              finalize_hint: *mut c_void,
+            ),
+        ),
+        Box::leak(Box::new(finalize_hint)) as *mut _ as *mut c_void,
+        &mut maybe_ref,
+      )
+    })
+  }
+}
+
+#[cfg(feature = "napi5")]
+unsafe extern "C" fn finalize_callback<T, Hint, F>(
+  raw_env: sys::napi_env,
+  finalize_data: *mut c_void,
+  finalize_hint: *mut c_void,
+) where
+  T: 'static,
+  Hint: 'static,
+  F: FnOnce(FinalizeContext<T, Hint>),
+{
+  let (value, callback, raw_ref) = *Box::from_raw(finalize_data as *mut (T, F, sys::napi_ref));
+  let hint = *Box::from_raw(finalize_hint as *mut Hint);
+  let env = Env::from_raw(raw_env);
+  callback(FinalizeContext { value, hint, env });
+  if !raw_ref.is_null() {
+    let status = sys::napi_delete_reference(raw_env, raw_ref);
+    debug_assert!(
+      status == sys::Status::napi_ok,
+      "Delete reference in finalize callback failed"
+    );
+  }
+}
+
 #[cfg(feature = "napi6")]
 pub enum KeyCollectionMode {
   IncludePrototypes,