fix(napi): allow cleanup hook to remove itself (denoland#17402)

This commit fixes "cleanup hooks" in NAPI integration in two ways:
- don't hold to RefCell's borrow while iterating over hooks
- allow a hook to remove itself when being called

ext/napi/lib.rs

@@ -343,11 +343,32 @@ pub struct NapiState {
 
 impl Drop for NapiState {
  fn drop(&mut self) {
- let mut hooks = self.env_cleanup_hooks.borrow_mut();
+ let hooks = {
+ let h = self.env_cleanup_hooks.borrow_mut();
+ h.clone()
+ };
+
  // Hooks are supposed to be run in LIFO order
- let hooks = hooks.drain(..).rev();
- for (fn_ptr, data) in hooks {
- (fn_ptr)(data);
+ let hooks_to_run = hooks.into_iter().rev();
+
+ for hook in hooks_to_run {
+ // This hook might have been removed by a previous hook, in such case skip it here.
+ if !self
+ .env_cleanup_hooks
+ .borrow()
+ .iter()
+ .any(|pair| pair.0 == hook.0 && pair.1 == hook.1)
+ {
+ continue;
+ }
+
+ (hook.0)(hook.1);
+ {
+ self
+ .env_cleanup_hooks
+ .borrow_mut()
+ .retain(|pair| !(pair.0 == hook.0 && pair.1 == hook.1));
+ }
  }
  }
 }

test_napi/src/lib.rs

@@ -66,6 +66,11 @@ extern "C" fn cleanup(arg: *mut c_void) {
  println!("cleanup({})", arg as i64);
 }
 
+extern "C" fn remove_this_hook(arg: *mut c_void) {
+ let env = arg as napi_env;
+ unsafe { napi_remove_env_cleanup_hook(env, Some(remove_this_hook), arg) };
+}
+
 static SECRET: i64 = 42;
 static WRONG_SECRET: i64 = 17;
 static THIRD_SECRET: i64 = 18;
@@ -81,6 +86,7 @@ extern "C" fn install_cleanup_hook(
  napi_add_env_cleanup_hook(env, Some(cleanup), WRONG_SECRET as *mut c_void);
  napi_add_env_cleanup_hook(env, Some(cleanup), SECRET as *mut c_void);
  napi_add_env_cleanup_hook(env, Some(cleanup), THIRD_SECRET as *mut c_void);
+ napi_add_env_cleanup_hook(env, Some(remove_this_hook), env as *mut c_void);
  napi_remove_env_cleanup_hook(
  env,
  Some(cleanup),