Add AnyUserData::type_id method

Author: khvzak

src/userdata.rs

@@ -623,10 +623,9 @@ impl AnyUserData {
     /// Checks whether the type of this userdata is `T`.
     #[inline]
     pub fn is<T: 'static>(&self) -> bool {
-        let lua = self.0.lua.lock();
-        let type_id = lua.get_userdata_ref_type_id(&self.0);
+        let type_id = self.type_id();
         // We do not use wrapped types here, rather prefer to check the "real" type of the userdata
-        matches!(type_id, Ok(Some(type_id)) if type_id == TypeId::of::<T>())
+        matches!(type_id, Some(type_id) if type_id == TypeId::of::<T>())
     }
 
     /// Borrow this userdata immutably if it is of type `T`.
@@ -918,6 +917,15 @@ impl AnyUserData {
         self.0.to_pointer()
     }
 
+    /// Returns [`TypeId`] of this userdata if it is registered and `'static`.
+    ///
+    /// This method is not available for scoped userdata.
+    #[inline]
+    pub fn type_id(&self) -> Option<TypeId> {
+        let lua = self.0.lua.lock();
+        lua.get_userdata_ref_type_id(&self.0).ok().flatten()
+    }
+
     /// Returns a type name of this `UserData` (from a metatable field).
     pub(crate) fn type_name(&self) -> Result<Option<StdString>> {
         let lua = self.0.lua.lock();

tests/userdata.rs

@@ -1,3 +1,4 @@
+use std::any::TypeId;
 use std::collections::HashMap;
 use std::string::String as StdString;
 use std::sync::Arc;
@@ -23,9 +24,11 @@ fn test_userdata() -> Result<()> {
     let userdata2 = lua.create_userdata(UserData2(Box::new(2)))?;
 
     assert!(userdata1.is::<UserData1>());
+    assert!(userdata1.type_id() == Some(TypeId::of::<UserData1>()));
     assert!(!userdata1.is::<UserData2>());
     assert!(userdata2.is::<UserData2>());
     assert!(!userdata2.is::<UserData1>());
+    assert!(userdata2.type_id() == Some(TypeId::of::<UserData2>()));
 
     assert_eq!(userdata1.borrow::<UserData1>()?.0, 1);
     assert_eq!(*userdata2.borrow::<UserData2>()?.0, 2);