Update LuaRef/LuaOwnedRef

Move content of `Lua::make_owned_ref` into `LuaRef::into_owned`
Add crate-visible `Lua::clone` function (not trait)

src/lua.rs

@@ -2493,23 +2493,15 @@ impl Lua {
         }
     }
 
-    pub(crate) fn drop_ref(&self, lref: &LuaRef) {
+    pub(crate) fn drop_ref_index(&self, index: c_int) {
         unsafe {
             let ref_thread = self.ref_thread();
             ffi::lua_pushnil(ref_thread);
-            ffi::lua_replace(ref_thread, lref.index);
-            (*self.extra.get()).ref_free.push(lref.index);
+            ffi::lua_replace(ref_thread, index);
+            (*self.extra.get()).ref_free.push(index);
         }
     }
 
-    #[cfg(feature = "unstable")]
-    pub(crate) fn make_owned_ref(&self, lref: LuaRef) -> crate::types::LuaOwnedRef {
-        assert!(lref.drop, "Cannot turn non-drop reference into owned");
-        let owned_ref = crate::types::LuaOwnedRef::new(Lua(self.0.clone()), lref.index);
-        mem::forget(lref);
-        owned_ref
-    }
-
     #[cfg(feature = "unstable")]
     pub(crate) fn adopt_owned_ref(&self, loref: crate::types::LuaOwnedRef) -> LuaRef {
         assert!(
@@ -3041,6 +3033,12 @@ impl Lua {
             .map(|x| x.as_ref().memory_limit == 0)
             .unwrap_or_default()
     }
+
+    #[cfg(feature = "unstable")]
+    #[inline]
+    pub(crate) fn clone(&self) -> Self {
+        Lua(Arc::clone(&self.0))
+    }
 }
 
 impl LuaInner {

src/types.rs

@@ -195,7 +195,10 @@ impl<'lua> LuaRef<'lua> {
     #[cfg(feature = "unstable")]
     #[inline]
     pub(crate) fn into_owned(self) -> LuaOwnedRef {
-        self.lua.make_owned_ref(self)
+        assert!(self.drop, "Cannot turn non-drop reference into owned");
+        let owned_ref = LuaOwnedRef::new(self.lua.clone(), self.index);
+        mem::forget(self);
+        owned_ref
     }
 }
 
@@ -214,7 +217,7 @@ impl<'lua> Clone for LuaRef<'lua> {
 impl<'lua> Drop for LuaRef<'lua> {
     fn drop(&mut self) {
         if self.drop {
-            self.lua.drop_ref(self);
+            self.lua.drop_ref_index(self.index);
         }
     }
 }
@@ -250,18 +253,14 @@ impl fmt::Debug for LuaOwnedRef {
 #[cfg(feature = "unstable")]
 impl Clone for LuaOwnedRef {
     fn clone(&self) -> Self {
-        self.lua.make_owned_ref(self.to_ref().clone())
+        self.to_ref().clone().into_owned()
     }
 }
 
 #[cfg(feature = "unstable")]
 impl Drop for LuaOwnedRef {
     fn drop(&mut self) {
-        drop(LuaRef {
-            lua: &self.lua,
-            index: self.index,
-            drop: true,
-        });
+        self.lua.drop_ref_index(self.index);
     }
 }