Code cleanup

src/userdata/any.rs

@@ -1,80 +1,48 @@
-use std::ffi::CStr;
-
-use crate::{ensure_type, FromLuaStack, LuaRef, PushToLuaStack, StackGuard, State, Userdata};
+use std::{cell::{Ref, RefCell, RefMut}, ffi::CStr};
 
 use mlua_sys as lua;
 
-pub struct UnsafeUserdata<'a> {
+use crate::{ensure_type, AsLua, FromLua, FromLuaStack, Function, IntoLuaVec, LuaRef, PushToLuaStack, StackGuard, State, Table, Userdata, Value};
+
+/// A handle to some userdata on the stack
+//#[derive(Clone)]
+pub struct AnyUserdata<'a> {
     pub(crate) lref: LuaRef<'a>,
     state: &'a State,
 }
 
-impl<'a> Clone for UnsafeUserdata<'a> {
+impl<'a> Clone for AnyUserdata<'a> {
     fn clone(&self) -> Self {
         Self {
-            lref: self.lref.clone(),
             state: self.state,
+            lref: self.lref.clone()
         }
     }
 }
 
-impl<'a> UnsafeUserdata<'a> {
+impl<'a> AnyUserdata<'a> {
     pub fn from_ref(state: &'a State, lref: LuaRef<'a>) -> Self {
         Self {
-            lref,
             state,
+            lref,
         }
     }
 
     /// Returns a borrow to the userdata.
-    pub fn as_ref<T: Userdata + 'static>(&self) -> crate::Result<&'a T> {
+    pub fn as_ref<T: Userdata + 'static>(&self) -> crate::Result<Ref<'a, T>> {
         unsafe {
-            self.state.ensure_stack(3)?;
-            let _g = StackGuard::new(self.state);
-            let s = self.state.state_ptr();
-
-            self.lref.push_to_lua_stack(self.state)?;
-            
-            if lua::lua_getmetatable(s, -1) == 0 {
-                return Err(crate::Error::UserdataMismatch);
-            }
-
-            self.state.get_userdata_metatable::<T>()
-                .push_to_lua_stack(self.state)?;
-
-            if lua::lua_rawequal(s, -2, -1) == 1 {
-                let cptr = lua::lua_touserdata(s, -3);
-                let t = &*cptr.cast::<T>();
-                Ok(t)
-            } else {
-                return Err(crate::Error::UserdataMismatch);
-            }
+            let cell = self.as_ptr::<T>()?;
+            let cell = cell.as_ref().unwrap();
+            Ok(cell.borrow())
         }
     }
 
     /// Returns a mutable reference to the userdata.
-    pub fn as_mut<T: Userdata + 'static>(&self) -> crate::Result<&'a mut T> {
+    pub fn as_mut<T: Userdata + 'static>(&self) -> crate::Result<RefMut<'a, T>> {
         unsafe {
-            self.state.ensure_stack(3)?;
-            let _g = StackGuard::new(self.state);
-            let s = self.state.state_ptr();
-
-            self.lref.push_to_lua_stack(self.state)?;
-            
-            if lua::lua_getmetatable(s, -1) == 0 {
-                return Err(crate::Error::MissingMetatable);
-            }
-
-            self.state.get_userdata_metatable::<T>()
-                .push_to_lua_stack(self.state)?;
-
-            if lua::lua_rawequal(s, -2, -1) == 1 {
-                let cptr = lua::lua_touserdata(s, -3);
-                let t = &mut *cptr.cast::<T>();
-                Ok(t)
-            } else {
-                Err(crate::Error::UserdataMismatch)
-            }
+            let cell = self.as_ptr::<T>()?;
+            let cell = cell.as_mut().unwrap();
+            Ok(cell.borrow_mut())
         }
     }
 
@@ -84,9 +52,9 @@ impl<'a> UnsafeUserdata<'a> {
     /// * You must be certain that the type `T` is the same type that this userdata has a handle to.
     ///   There is a blind cast from `void*` to `T*`
     /// 
-    /// If there is a possibility that these types do not match, use [`UnsafeUserdata::as_ptr`]
+    /// If there is a possibility that these types do not match, use [`AnyUserdata::as_ptr`]
     /// which does verify the types.
-    pub unsafe fn as_ptr_unchecked<T>(&self) -> crate::Result<*mut T> {
+    pub unsafe fn as_ptr_unchecked<T: Userdata + 'static>(&self) -> crate::Result<*mut RefCell<T>> {
         self.state.ensure_stack(1)?;
         let _g = StackGuard::new(self.state);
         let s = self.state.state_ptr();
@@ -97,11 +65,11 @@ impl<'a> UnsafeUserdata<'a> {
         Ok(cptr.cast())
     }
 
-    /// Returns a mutable pointer of the data stored.
+    /// Returns a mutable pointer of the [`RefCell`] storing the userdata.
     /// 
     /// This function ensures that the type of the userdata this struct has a handle to is the
     /// same as `T`. If it isn't, a `UserdataMismatch` error will be returned.
-    pub unsafe fn as_ptr<T: Userdata + 'static>(&self) -> crate::Result<*mut T> {
+    pub unsafe fn as_ptr<T: Userdata + 'static>(&self) -> crate::Result<*mut RefCell<T>> {
         let _g = StackGuard::new(self.state);
         let s = self.state.state_ptr();
 
@@ -148,33 +116,108 @@ impl<'a> UnsafeUserdata<'a> {
             Ok(cstr.to_string())
         }
     }
+
+    /// Returns the metatable of this userdata
+    pub fn get_metatable(&'a self) -> crate::Result<Table<'a>> {
+        unsafe {
+            self.state.ensure_stack(2)?;
+            let _g = StackGuard::new(self.state);
+
+            //self.unsafe_ud.lref.push_to_lua_stack(self.state)?;
+            self.push_to_lua_stack(self.state)?;
+            let s = self.state.state_ptr();
+
+            if lua::lua_getmetatable(s, -1) == 0 {
+                Err(crate::Error::MissingMetatable)
+            } else {
+                let mut t = Table::from_lua_stack(self.state)?;
+                t.mt_marker = true;
+
+                Ok(t)
+            }
+        }
     }
 
-impl<'a> FromLuaStack<'a> for UnsafeUserdata<'a> {
+    /// Gets something from the userdata.
+    /// 
+    /// Will trigger a call to the `__index` metamethod. Use [`AnyUserdata::raw_get`] if you
+    /// don't want to call it.
+    pub fn get<K, V>(&'a self, key: K) -> crate::Result<V>
+    where
+        K: AsLua<'a>,
+        V: FromLua<'a>,
+    {
+        let mt = self.get_metatable()?;
+        mt.get::<K, V>(key)
+    }
+
+    /// Gets something from the userdata. Will **not** trigger a call to the `__index` metamethod.
+    pub fn raw_get<K, V>(&'a self, key: K) -> crate::Result<V>
+    where
+        K: AsLua<'a>,
+        V: FromLua<'a>,
+    {
+        let mt = self.get_metatable()?;
+        mt.raw_get::<K, V>(key)
+    }
+
+    /// Execute a method on this userdata. This finds a function with `name` and executes it
+    /// with the userdata as the first argument.
+    pub fn execute_method<A, R>(&'a self, name: &str, args: A) -> crate::Result<R>
+    where
+        A: IntoLuaVec<'a>,
+        R: FromLua<'a>,
+    {
+        let name = name.to_string();
+        let mt = self.get_metatable()?;
+        let f = mt.get::<_, Function>(name)?;
+        
+        let mut args = args.into_lua_value_vec(self.state)?;
+        args.push_front(self.clone().as_lua(self.state)?);
+
+        f.exec(args)
+    }
+}
+
+impl<'a> FromLuaStack<'a> for AnyUserdata<'a> {
     unsafe fn from_lua_stack(state: &'a State) -> crate::Result<Self> {
         ensure_type(state, lua::LUA_TUSERDATA, -1)?;
 
-        Ok(UnsafeUserdata {
-            lref: LuaRef::from_stack(state)?,
+        Ok(AnyUserdata {
             state,
+            lref: LuaRef::from_stack(state)?,
         })
     }
 }
 
-impl<'a> PushToLuaStack<'a> for UnsafeUserdata<'a> {
+impl<'a> PushToLuaStack<'a> for AnyUserdata<'a> {
     unsafe fn push_to_lua_stack(&self, state: &'a State) -> crate::Result<()> {
         self.lref.push_to_lua_stack(state)
     }
 }
 
-/* impl<'a> AsLua<'a> for UnsafeUserdata<'a> {
+impl<'a> AsLua<'a> for AnyUserdata<'a> {
     fn as_lua(&self, _lua: &'a State) -> crate::Result<Value<'a>> {
         Ok(Value::Userdata(self.clone()))
     }
 }
 
-impl<'a> FromLua<'a> for UnsafeUserdata<'a> {
+impl<'a> FromLua<'a> for AnyUserdata<'a> {
     fn from_lua(_lua: &State, val: Value<'a>) -> crate::Result<Self> {
         val.into_userdata()
     }
-} */
+}
+
+impl<'a, T: Userdata + 'static> FromLua<'a> for Ref<'a, T> {
+    fn from_lua(_lua: &'a State, val: Value<'a>) -> crate::Result<Self> {
+        let ud = val.into_userdata()?;
+        ud.as_ref::<T>()
+    }
+}
+
+impl<'a, T: Userdata + 'static> FromLua<'a> for RefMut<'a, T> {
+    fn from_lua(_lua: &'a State, val: Value<'a>) -> crate::Result<Self> {
+        let ud = val.into_userdata()?;
+        ud.as_mut::<T>()
+    }
+}

src/userdata/builder.rs

@@ -0,0 +1,283 @@
+use std::{cell::OnceCell, collections::HashMap, marker::PhantomData, mem, ops::DerefMut, sync::Arc};
+
+use crate::{AnyUserdata, AsLua, FromLua, FromLuaVec, State, Userdata, Value, ValueVec};
+
+pub type UserdataFn<'a> = Box<dyn Fn(&'a State, ValueVec<'a>) -> crate::Result<Value<'a>>>;
+pub type UserdataGetterFn<'a> = Arc<OnceCell<Box<dyn Fn(AnyUserdata<'a>) -> crate::Result<*const ()>>>>;
+pub type UserdataMutGetterFn<'a> = Arc<OnceCell<Box<dyn Fn(AnyUserdata<'a>) -> crate::Result<*mut ()>>>>;
+
+pub struct UserdataBuilder<'a, T> {
+    pub(crate) name: String,
+    pub(crate) field_getters: HashMap<String, UserdataFn<'a>>,
+    pub(crate) field_setters: HashMap<String, UserdataFn<'a>>,
+    pub(crate) functions: HashMap<String, UserdataFn<'a>>,
+    pub(crate) meta_methods: HashMap<String, UserdataFn<'a>>,
+
+    pub(crate) wrapped_getter: Arc<OnceCell<Box<dyn Fn(AnyUserdata<'a>) -> crate::Result<*const ()>>>>,
+    pub(crate) wrapped_getter_mut: Arc<OnceCell<Box<dyn Fn(AnyUserdata<'a>) -> crate::Result<*mut ()>>>>,
+
+    _marker: PhantomData<T>,
+}
+
+impl<'a, T: Userdata> UserdataBuilder<'a, T> {
+    pub fn new() -> Self {
+        Self {
+            name: T::name(),
+            field_getters: HashMap::new(),
+            field_setters: HashMap::new(),
+            functions: HashMap::new(),
+            meta_methods: HashMap::new(),
+            wrapped_getter: Arc::new(OnceCell::new()),
+            wrapped_getter_mut: Arc::new(OnceCell::new()),
+            _marker: PhantomData,
+        }
+    }
+
+    pub fn field_getter<F, R>(&mut self, name: &str, f: F) -> &mut Self
+    where
+        F: Fn(&'a State, &T) -> crate::Result<R> + 'static,
+        R: AsLua<'a>,
+        T: Userdata + 'static
+    {
+        let wrapped = self.wrapped_getter.clone();
+        let wrapped: Arc<OnceCell<Box<dyn Fn(AnyUserdata<'_>) -> Result<*const (), crate::Error>>>> = unsafe { mem::transmute(wrapped) };
+        
+        let ud_name = self.name.clone();
+        let fn_name = name.to_string();
+
+        let wrap = move |lua: &'a State, mut val: ValueVec<'a>| {
+            let val = val.pop_front().unwrap();
+            let this = val.as_userdata().unwrap(); // if this panics, its a bug
+
+            if let Some(getter) = wrapped.get() {
+                let this_ptr = Self::result_to_bad_arg(
+                    getter(this.clone()),
+                    &ud_name,
+                    &fn_name,
+                    1,
+                    Some("self")
+                )?;
+                let this_ptr = this_ptr.cast::<T>();
+                let this = unsafe { &*this_ptr };
+
+                f(lua, this).and_then(|r| r.as_lua(lua))
+            } else {
+                let this = this.as_ref::<T>()?;
+                f(lua, &*this).and_then(|r| r.as_lua(lua))
+            }
+        };
+        self.field_getters.insert(name.to_string(), Box::new(wrap));
+
+        self
+    }
+
+    pub fn field_setter<F, V>(&mut self, name: &str, f: F) -> &mut Self
+    where
+        F: Fn(&'a State, &mut T, V) -> () + 'static,
+        V: FromLua<'a>,
+        T: Userdata + 'static
+    {
+        let wrapped = self.wrapped_getter_mut.clone();
+        let wrapped: Arc<OnceCell<Box<dyn Fn(AnyUserdata<'_>) -> Result<*mut (), crate::Error>>>> = unsafe { mem::transmute(wrapped) };
+        
+        let ud_name = self.name.clone();
+        let fn_name = name.to_string();
+
+        let wrap = move |lua: &'a State, mut val: ValueVec<'a>| {
+            let lua_val = val.pop_front().unwrap();
+            let this = lua_val.as_userdata().unwrap(); // if this panics, its a bug
+
+            let lua_val = val.pop_front().unwrap();
+            let v_arg = V::from_lua(lua, lua_val)?;
+
+            if let Some(mut_getter) = wrapped.get() {
+                let this_ptr = Self::result_to_bad_arg(
+                    mut_getter(this.clone()),
+                    &ud_name,
+                    &fn_name,
+                    1,
+                    Some("self")
+                )?;
+                let this_ptr = this_ptr.cast::<T>();
+                let this = unsafe { this_ptr.as_mut().unwrap() };
+
+                f(lua, this, v_arg).as_lua(lua)
+            } else {
+                let mut this = this.as_mut::<T>()?;
+
+                f(lua, this.deref_mut(), v_arg).as_lua(lua)
+            }
+        };
+        self.field_setters.insert(name.to_string(), Box::new(wrap));
+
+        self
+    }
+
+    fn arg_result_to_bad_arg<R>(res: crate::Result<R>, ud_name: &str, fn_name: &str) -> crate::Result<R> {
+        res.map_err(|e| match e {
+            crate::Error::ValueVecError { value_idx, error } => {
+                let full_name = format!("{}.{}", ud_name, fn_name);
+                // added 2 to value index since the error idx starts at 0,
+                // and `this` counts as the first argument in the lua function.
+                crate::Error::BadArgument { func: Some(full_name), arg_index: value_idx + 2, arg_name: None, error, }
+            },
+            _ => e
+        })
+    }
+
+    fn result_to_bad_arg<R>(res: crate::Result<R>, ud_name: &str, fn_name: &str, arg_idx: i32, arg_name: Option<&str>) -> crate::Result<R> {
+        res.map_err(|e| {
+            let full_name = format!("{}.{}", ud_name, fn_name);
+            let arg_name = arg_name.map(|s| s.to_string());
+
+            crate::Error::BadArgument { func: Some(full_name), arg_index: arg_idx, arg_name, error: Arc::new(e), }
+        })
+    }
+
+    pub fn function<F, R, A>(&mut self, name: &str, f: F) -> &mut Self
+    where
+        F: Fn(&'a State, A) -> crate::Result<R> + 'static,
+        A: FromLuaVec<'a>,
+        R: AsLua<'a>,
+    {
+        let ud_name = self.name.clone();
+        let fn_name = name.to_string();
+        let wrap = move |lua: &'a State, val: ValueVec<'a>| {
+            let args = Self::arg_result_to_bad_arg(
+                A::from_lua_value_vec(lua, val),
+                &ud_name, &fn_name
+            )?;
+            f(lua, args).and_then(|r| r.as_lua(lua))
+        };
+        self.functions.insert(name.to_string(), Box::new(wrap));
+
+        self
+    }
+
+    pub fn method<F, R, A>(&mut self, name: &str, f: F) -> &mut Self
+    where
+        F: Fn(&'a State, &T, A) -> crate::Result<R> + 'static,
+        A: FromLuaVec<'a>,
+        R: AsLua<'a>,
+        T: Userdata + 'static
+    {
+        let wrapped = self.wrapped_getter.clone();
+        let wrapped: Arc<OnceCell<Box<dyn Fn(AnyUserdata<'_>) -> Result<*const (), crate::Error>>>> = unsafe { mem::transmute(wrapped) };
+
+        let ud_name = self.name.clone();
+        let fn_name = name.to_string();
+        
+        let wrap = move |lua: &'a State, mut val: ValueVec<'a>| {
+            let this_val = val.pop_front().unwrap();
+            let this = this_val.as_userdata().unwrap(); // if this panics, its a bug
+
+            let args = Self::arg_result_to_bad_arg(
+                A::from_lua_value_vec(lua, val),
+                &ud_name, &fn_name
+            )?;
+
+            if let Some(mut_getter) = wrapped.get() {
+                let this_ptr = Self::result_to_bad_arg(
+                    mut_getter(this.clone()),
+                    &ud_name,
+                    &fn_name,
+                    1,
+                    Some("self")
+                )?;
+                let this_ptr = this_ptr.cast::<T>();
+                let this = unsafe { this_ptr.as_ref().unwrap() };
+
+                f(lua, this, args).and_then(|r| r.as_lua(lua))
+            } else {
+                let this = this.as_ref::<T>()?;
+
+                f(lua, &*this, args).and_then(|r| r.as_lua(lua))
+            }
+        };
+        self.functions.insert(name.to_string(), Box::new(wrap));
+
+        self
+    }
+
+    pub fn method_mut<F, R, A>(&mut self, name: &str, f: F) -> &mut Self
+    where
+        F: Fn(&'a State, &mut T, A) -> crate::Result<R> + 'static,
+        A: FromLuaVec<'a>,
+        R: AsLua<'a>,
+        T: Userdata + 'static
+    {
+        let wrapped = self.wrapped_getter_mut.clone();
+        let wrapped: Arc<OnceCell<Box<dyn Fn(AnyUserdata<'_>) -> Result<*mut (), crate::Error>>>> = unsafe { mem::transmute(wrapped) };
+
+        let ud_name = self.name.clone();
+        let fn_name = name.to_string();
+        
+        let wrap = move |lua: &'a State, mut val: ValueVec<'a>| {
+            let this_val = val.pop_front().unwrap();
+            let this = this_val.as_userdata().unwrap(); // if this panics, its a bug
+
+            let args = Self::arg_result_to_bad_arg(
+                A::from_lua_value_vec(lua, val),
+                &ud_name, &fn_name
+            )?;
+
+            if let Some(mut_getter) = wrapped.get() {
+                let this_ptr = Self::result_to_bad_arg(
+                    mut_getter(this.clone()),
+                    &ud_name,
+                    &fn_name,
+                    1,
+                    Some("self")
+                )?;
+                let this_ptr = this_ptr.cast::<T>();
+                let this = unsafe { this_ptr.as_mut().unwrap() };
+
+                f(lua, this, args).and_then(|r| r.as_lua(lua))
+            } else {
+                let mut this = this.as_mut::<T>()?;
+
+                f(lua, this.deref_mut(), args).and_then(|r| r.as_lua(lua))
+            }
+        };
+        self.functions.insert(name.to_string(), Box::new(wrap));
+
+        self
+    }
+
+    pub fn meta_method<N, F, R, A>(&mut self, name: N, f: F) -> &mut Self
+    where
+        N: AsRef<str>,
+        F: Fn(&'a State, &T, A) -> crate::Result<R> + 'static,
+        A: FromLuaVec<'a>,
+        R: AsLua<'a>,
+        T: Userdata + 'static
+    {
+        let ud_name = self.name.clone();
+        let fn_name = name.as_ref().to_string();
+        let wrap = move |lua: &'a State, mut val: ValueVec<'a>| {
+            let this_val = val.pop_front().unwrap();
+            let this = this_val.as_userdata().unwrap(); // if this panics, its a bug
+            let this = this.as_ref::<T>()?;
+
+            let args = Self::arg_result_to_bad_arg(
+                A::from_lua_value_vec(lua, val),
+                &ud_name, &fn_name
+            )?;
+            
+            f(lua, &*this, args).and_then(|r| r.as_lua(lua))
+        };
+        self.meta_methods.insert(name.as_ref().to_string(), Box::new(wrap));
+
+        self
+    }
+
+    //fn append_fields_from<S>(&mut self, other: UserDataRegistry<'lua, S>) {
+    pub fn expand_with<U>(&mut self, other: UserdataBuilder<'a, U>) {
+        self.field_getters = other.field_getters;
+        self.field_setters = other.field_setters;
+        self.functions = other.functions;
+        self.meta_methods = other.meta_methods;
+        self.wrapped_getter = other.wrapped_getter;
+        self.wrapped_getter_mut = other.wrapped_getter_mut;
+    }
+}

src/userdata/mod.rs

@@ -1,27 +1,26 @@
-use std::{cell::{OnceCell, Ref, RefCell, RefMut}, collections::HashMap, ffi::CStr, marker::PhantomData, mem, ops::DerefMut, sync::Arc};
+use crate::{AsLua, PushToLuaStack, State, Value};
 
-use crate::{ensure_type, AsLua, FromLua, FromLuaStack, FromLuaVec, Function, IntoLuaVec, LuaRef, PushToLuaStack, StackGuard, State, Table, Value, ValueVec};
-
-use mlua_sys as lua;
-
-pub mod unsafe_ud;
-pub use unsafe_ud::*;
+pub mod any;
+#[allow(unused_imports)]
+pub use any::*;
 
 pub mod proxy;
 #[allow(unused_imports)]
-use proxy::*;
+pub use proxy::*;
+
+pub mod builder;
+#[allow(unused_imports)]
+pub use builder::*;
 
 pub mod borrow;
 #[allow(unused_imports)]
-use borrow::*;
+pub use borrow::*;
 
 pub mod borrow_mut;
 #[allow(unused_imports)]
-use borrow_mut::*;
+pub use borrow_mut::*;
 
-
-/// An enum representing all Lua MetaMethods
-/// https://gist.github.com/oatmealine/655c9e64599d0f0dd47687c1186de99f
+/// An enum representing Lua meta methods and fields
 pub enum MetaMethod {
     Add,
     Sub,
@@ -105,499 +104,8 @@ impl<'a> PushToLuaStack<'a> for MetaMethod {
     }
 }
 
-pub type UserdataFn<'a> = Box<dyn Fn(&'a State, ValueVec<'a>) -> crate::Result<Value<'a>>>;
-pub type UserdataGetterFn<'a> = Arc<OnceCell<Box<dyn Fn(AnyUserdata<'a>) -> crate::Result<*const ()>>>>;
-pub type UserdataMutGetterFn<'a> = Arc<OnceCell<Box<dyn Fn(AnyUserdata<'a>) -> crate::Result<*mut ()>>>>;
-
-pub struct UserdataBuilder<'a, T> {
-    pub(crate) name: String,
-    pub(crate) field_getters: HashMap<String, UserdataFn<'a>>,
-    pub(crate) field_setters: HashMap<String, UserdataFn<'a>>,
-    pub(crate) functions: HashMap<String, UserdataFn<'a>>,
-    pub(crate) meta_methods: HashMap<String, UserdataFn<'a>>,
-
-    pub(crate) wrapped_getter: Arc<OnceCell<Box<dyn Fn(AnyUserdata<'a>) -> crate::Result<*const ()>>>>,
-    pub(crate) wrapped_getter_mut: Arc<OnceCell<Box<dyn Fn(AnyUserdata<'a>) -> crate::Result<*mut ()>>>>,
-
-    _marker: PhantomData<T>,
-}
-
-impl<'a, T: Userdata> UserdataBuilder<'a, T> {
-    pub fn new() -> Self {
-        Self {
-            name: T::name(),
-            field_getters: HashMap::new(),
-            field_setters: HashMap::new(),
-            functions: HashMap::new(),
-            meta_methods: HashMap::new(),
-            wrapped_getter: Arc::new(OnceCell::new()),
-            wrapped_getter_mut: Arc::new(OnceCell::new()),
-            _marker: PhantomData,
-        }
-    }
-
-    pub fn field_getter<F, R>(&mut self, name: &str, f: F) -> &mut Self
-    where
-        F: Fn(&'a State, &T) -> crate::Result<R> + 'static,
-        R: AsLua<'a>,
-        T: Userdata + 'static
-    {
-        let wrapped = self.wrapped_getter.clone();
-        let wrapped: Arc<OnceCell<Box<dyn Fn(AnyUserdata<'_>) -> Result<*const (), crate::Error>>>> = unsafe { mem::transmute(wrapped) };
-        
-        let ud_name = self.name.clone();
-        let fn_name = name.to_string();
-
-        let wrap = move |lua: &'a State, mut val: ValueVec<'a>| {
-            let val = val.pop_front().unwrap();
-            let this = val.as_userdata().unwrap(); // if this panics, its a bug
-
-            if let Some(getter) = wrapped.get() {
-                let this_ptr = Self::result_to_bad_arg(
-                    getter(this.clone()),
-                    &ud_name,
-                    &fn_name,
-                    1,
-                    Some("self")
-                )?;
-                let this_ptr = this_ptr.cast::<T>();
-                let this = unsafe { &*this_ptr };
-
-                f(lua, this).and_then(|r| r.as_lua(lua))
-            } else {
-                let this = this.as_ref::<T>()?;
-                f(lua, &*this).and_then(|r| r.as_lua(lua))
-            }
-        };
-        self.field_getters.insert(name.to_string(), Box::new(wrap));
-
-        self
-    }
-
-    pub fn field_setter<F, V>(&mut self, name: &str, f: F) -> &mut Self
-    where
-        F: Fn(&'a State, &mut T, V) -> () + 'static,
-        V: FromLua<'a>,
-        T: Userdata + 'static
-    {
-        let wrapped = self.wrapped_getter_mut.clone();
-        let wrapped: Arc<OnceCell<Box<dyn Fn(AnyUserdata<'_>) -> Result<*mut (), crate::Error>>>> = unsafe { mem::transmute(wrapped) };
-        
-        let ud_name = self.name.clone();
-        let fn_name = name.to_string();
-
-        let wrap = move |lua: &'a State, mut val: ValueVec<'a>| {
-            let lua_val = val.pop_front().unwrap();
-            let this = lua_val.as_userdata().unwrap(); // if this panics, its a bug
-
-            let lua_val = val.pop_front().unwrap();
-            let v_arg = V::from_lua(lua, lua_val)?;
-
-            if let Some(mut_getter) = wrapped.get() {
-                let this_ptr = Self::result_to_bad_arg(
-                    mut_getter(this.clone()),
-                    &ud_name,
-                    &fn_name,
-                    1,
-                    Some("self")
-                )?;
-                let this_ptr = this_ptr.cast::<T>();
-                let this = unsafe { this_ptr.as_mut().unwrap() };
-
-                f(lua, this, v_arg).as_lua(lua)
-            } else {
-                let mut this = this.as_mut::<T>()?;
-
-                f(lua, this.deref_mut(), v_arg).as_lua(lua)
-            }
-        };
-        self.field_setters.insert(name.to_string(), Box::new(wrap));
-
-        self
-    }
-
-    fn arg_result_to_bad_arg<R>(res: crate::Result<R>, ud_name: &str, fn_name: &str) -> crate::Result<R> {
-        res.map_err(|e| match e {
-            crate::Error::ValueVecError { value_idx, error } => {
-                let full_name = format!("{}.{}", ud_name, fn_name);
-                // added 2 to value index since the error idx starts at 0,
-                // and `this` counts as the first argument in the lua function.
-                crate::Error::BadArgument { func: Some(full_name), arg_index: value_idx + 2, arg_name: None, error, }
-            },
-            _ => e
-        })
-    }
-
-    fn result_to_bad_arg<R>(res: crate::Result<R>, ud_name: &str, fn_name: &str, arg_idx: i32, arg_name: Option<&str>) -> crate::Result<R> {
-        res.map_err(|e| {
-            let full_name = format!("{}.{}", ud_name, fn_name);
-            let arg_name = arg_name.map(|s| s.to_string());
-
-            crate::Error::BadArgument { func: Some(full_name), arg_index: arg_idx, arg_name, error: Arc::new(e), }
-        })
-    }
-
-    pub fn function<F, R, A>(&mut self, name: &str, f: F) -> &mut Self
-    where
-        F: Fn(&'a State, A) -> crate::Result<R> + 'static,
-        A: FromLuaVec<'a>,
-        R: AsLua<'a>,
-    {
-        let ud_name = self.name.clone();
-        let fn_name = name.to_string();
-        let wrap = move |lua: &'a State, val: ValueVec<'a>| {
-            let args = Self::arg_result_to_bad_arg(
-                A::from_lua_value_vec(lua, val),
-                &ud_name, &fn_name
-            )?;
-            f(lua, args).and_then(|r| r.as_lua(lua))
-        };
-        self.functions.insert(name.to_string(), Box::new(wrap));
-
-        self
-    }
-
-    pub fn method<F, R, A>(&mut self, name: &str, f: F) -> &mut Self
-    where
-        F: Fn(&'a State, &T, A) -> crate::Result<R> + 'static,
-        A: FromLuaVec<'a>,
-        R: AsLua<'a>,
-        T: Userdata + 'static
-    {
-        let wrapped = self.wrapped_getter.clone();
-        let wrapped: Arc<OnceCell<Box<dyn Fn(AnyUserdata<'_>) -> Result<*const (), crate::Error>>>> = unsafe { mem::transmute(wrapped) };
-
-        let ud_name = self.name.clone();
-        let fn_name = name.to_string();
-        
-        let wrap = move |lua: &'a State, mut val: ValueVec<'a>| {
-            let this_val = val.pop_front().unwrap();
-            let this = this_val.as_userdata().unwrap(); // if this panics, its a bug
-
-            let args = Self::arg_result_to_bad_arg(
-                A::from_lua_value_vec(lua, val),
-                &ud_name, &fn_name
-            )?;
-
-            if let Some(mut_getter) = wrapped.get() {
-                let this_ptr = Self::result_to_bad_arg(
-                    mut_getter(this.clone()),
-                    &ud_name,
-                    &fn_name,
-                    1,
-                    Some("self")
-                )?;
-                let this_ptr = this_ptr.cast::<T>();
-                let this = unsafe { this_ptr.as_ref().unwrap() };
-
-                f(lua, this, args).and_then(|r| r.as_lua(lua))
-            } else {
-                let this = this.as_ref::<T>()?;
-
-                f(lua, &*this, args).and_then(|r| r.as_lua(lua))
-            }
-        };
-        self.functions.insert(name.to_string(), Box::new(wrap));
-
-        self
-    }
-
-    pub fn method_mut<F, R, A>(&mut self, name: &str, f: F) -> &mut Self
-    where
-        F: Fn(&'a State, &mut T, A) -> crate::Result<R> + 'static,
-        A: FromLuaVec<'a>,
-        R: AsLua<'a>,
-        T: Userdata + 'static
-    {
-        let wrapped = self.wrapped_getter_mut.clone();
-        let wrapped: Arc<OnceCell<Box<dyn Fn(AnyUserdata<'_>) -> Result<*mut (), crate::Error>>>> = unsafe { mem::transmute(wrapped) };
-
-        let ud_name = self.name.clone();
-        let fn_name = name.to_string();
-        
-        let wrap = move |lua: &'a State, mut val: ValueVec<'a>| {
-            let this_val = val.pop_front().unwrap();
-            let this = this_val.as_userdata().unwrap(); // if this panics, its a bug
-
-            let args = Self::arg_result_to_bad_arg(
-                A::from_lua_value_vec(lua, val),
-                &ud_name, &fn_name
-            )?;
-
-            if let Some(mut_getter) = wrapped.get() {
-                let this_ptr = Self::result_to_bad_arg(
-                    mut_getter(this.clone()),
-                    &ud_name,
-                    &fn_name,
-                    1,
-                    Some("self")
-                )?;
-                let this_ptr = this_ptr.cast::<T>();
-                let this = unsafe { this_ptr.as_mut().unwrap() };
-
-                f(lua, this, args).and_then(|r| r.as_lua(lua))
-            } else {
-                let mut this = this.as_mut::<T>()?;
-
-                f(lua, this.deref_mut(), args).and_then(|r| r.as_lua(lua))
-            }
-        };
-        self.functions.insert(name.to_string(), Box::new(wrap));
-
-        self
-    }
-
-    pub fn meta_method<N, F, R, A>(&mut self, name: N, f: F) -> &mut Self
-    where
-        N: AsRef<str>,
-        F: Fn(&'a State, &T, A) -> crate::Result<R> + 'static,
-        A: FromLuaVec<'a>,
-        R: AsLua<'a>,
-        T: Userdata + 'static
-    {
-        let ud_name = self.name.clone();
-        let fn_name = name.as_ref().to_string();
-        let wrap = move |lua: &'a State, mut val: ValueVec<'a>| {
-            let this_val = val.pop_front().unwrap();
-            let this = this_val.as_userdata().unwrap(); // if this panics, its a bug
-            let this = this.as_ref::<T>()?;
-
-            let args = Self::arg_result_to_bad_arg(
-                A::from_lua_value_vec(lua, val),
-                &ud_name, &fn_name
-            )?;
-            
-            f(lua, &*this, args).and_then(|r| r.as_lua(lua))
-        };
-        self.meta_methods.insert(name.as_ref().to_string(), Box::new(wrap));
-
-        self
-    }
-
-    //fn append_fields_from<S>(&mut self, other: UserDataRegistry<'lua, S>) {
-    pub fn expand_with<U>(&mut self, other: UserdataBuilder<'a, U>) {
-        self.field_getters = other.field_getters;
-        self.field_setters = other.field_setters;
-        self.functions = other.functions;
-        self.meta_methods = other.meta_methods;
-        self.wrapped_getter = other.wrapped_getter;
-        self.wrapped_getter_mut = other.wrapped_getter_mut;
-    }
-}
-
 pub trait Userdata: Sized {
     fn name() -> String;
 
     fn build<'a>(state: &State, builder: &mut UserdataBuilder<'a, Self>) -> crate::Result<()>;
 }
-
-/// A handle to some userdata on the stack
-//#[derive(Clone)]
-pub struct AnyUserdata<'a> {
-    pub(crate) unsafe_ud: UnsafeUserdata<'a>,
-    state: &'a State,
-}
-
-impl<'a> Clone for AnyUserdata<'a> {
-    fn clone(&self) -> Self {
-        Self {
-            state: self.state,
-            unsafe_ud: self.unsafe_ud.clone()
-        }
-    }
-}
-
-impl<'a> AnyUserdata<'a> {
-    pub fn from_ref(state: &'a State, lref: LuaRef<'a>) -> Self {
-        Self {
-            state,
-            unsafe_ud: UnsafeUserdata::from_ref(state, lref)
-        }
-    }
-
-    /// Returns a borrow to the userdata.
-    pub fn as_ref<T: Userdata + 'static>(&self) -> crate::Result<Ref<'a, T>> {
-        unsafe {
-            let cell = &*self.unsafe_ud.as_ptr_unchecked::<RefCell<T>>()?;
-            Ok(cell.borrow())
-        }
-    }
-
-    /// Returns a mutable reference to the userdata.
-    pub fn as_mut<T: Userdata + 'static>(&self) -> crate::Result<RefMut<'a, T>> {
-        unsafe {
-            let cell = &*self.unsafe_ud.as_ptr_unchecked::<RefCell<T>>()?;
-            Ok(cell.borrow_mut())
-        }
-    }
-
-    /// Returns a mutable pointer of the [`RefCell`] of userdata **WITHOUT verifying the type of it**.
-    /// 
-    /// # Safety
-    /// * You must be certain that the type `T` is the same type that this userdata has a handle to.
-    ///   There is a blind cast from `void*` to `T*`
-    /// 
-    /// If there is a possibility that these types do not match, use [`AnyUserdata::as_ptr`]
-    /// which does verify the types.
-    pub unsafe fn as_ptr_unchecked<T: Userdata + 'static>(&self) -> crate::Result<*mut RefCell<T>> {
-        let cell = self.unsafe_ud.as_ptr_unchecked::<RefCell<T>>()?;
-        Ok(cell)
-    }
-
-    /// Returns a mutable pointer of the [`RefCell`] storing the userdata.
-    /// 
-    /// This function ensures that the type of the userdata this struct has a handle to is the
-    /// same as `T`. If it isn't, a `UserdataMismatch` error will be returned.
-    pub unsafe fn as_ptr<T: Userdata + 'static>(&self) -> crate::Result<*mut RefCell<T>> {
-        let _g = StackGuard::new(self.state);
-        let s = self.state.state_ptr();
-
-        self.unsafe_ud.lref.push_to_lua_stack(self.state)?;
-        
-        if lua::lua_getmetatable(s, -1) == 0 {
-            return Err(crate::Error::MissingMetatable);
-        }
-
-        self.state.get_userdata_metatable::<T>()
-            .push_to_lua_stack(self.state)?;
-
-        if lua::lua_rawequal(s, -2, -1) == 1 {
-            drop(_g);
-            let cell = self.unsafe_ud.as_ptr_unchecked::<RefCell<T>>()?;
-            Ok(cell)
-        } else {
-            Err(crate::Error::UserdataMismatch)
-        }
-    }
-
-    /// Returns the name of the userdata by accessing the metatable
-    pub fn name(&self) -> crate::Result<String> {
-        unsafe {
-            self.state.ensure_stack(3)?;
-            let _g = StackGuard::new(self.state);
-
-            self.unsafe_ud.lref.push_to_lua_stack(self.state)?;
-            let s = self.state.state_ptr();
-
-            if lua::lua_getmetatable(s, -1) == 0 {
-                return Err(crate::Error::MissingMetatable);
-            }
-
-            lua::lua_pushliteral(s, "__name");
-            lua::lua_rawget(s, -2);
-            
-            ensure_type(self.state, lua::LUA_TSTRING, -1)?;
-
-            let cstr = CStr::from_ptr(lua::lua_tostring(s, -1));
-            let cstr = cstr.to_str()
-                // on panic, this should be considered a bug
-                .expect("Metatable name has invalid utf8 bytes!");
-
-            Ok(cstr.to_string())
-        }
-    }
-
-    /// Returns the metatable of this userdata
-    pub fn get_metatable(&'a self) -> crate::Result<Table<'a>> {
-        unsafe {
-            self.state.ensure_stack(2)?;
-            let _g = StackGuard::new(self.state);
-
-            //self.unsafe_ud.lref.push_to_lua_stack(self.state)?;
-            self.push_to_lua_stack(self.state)?;
-            let s = self.state.state_ptr();
-
-            if lua::lua_getmetatable(s, -1) == 0 {
-                Err(crate::Error::MissingMetatable)
-            } else {
-                let mut t = Table::from_lua_stack(self.state)?;
-                t.mt_marker = true;
-
-                Ok(t)
-            }
-        }
-    }
-
-    /// Gets something from the userdata.
-    /// 
-    /// Will trigger a call to the `__index` metamethod. Use [`AnyUserdata::raw_get`] if you
-    /// don't want to call it.
-    pub fn get<K, V>(&'a self, key: K) -> crate::Result<V>
-    where
-        K: AsLua<'a>,
-        V: FromLua<'a>,
-    {
-        let mt = self.get_metatable()?;
-        mt.get::<K, V>(key)
-    }
-
-    /// Gets something from the userdata. Will **not** trigger a call to the `__index` metamethod.
-    pub fn raw_get<K, V>(&'a self, key: K) -> crate::Result<V>
-    where
-        K: AsLua<'a>,
-        V: FromLua<'a>,
-    {
-        let mt = self.get_metatable()?;
-        mt.raw_get::<K, V>(key)
-    }
-
-    /// Execute a method on this userdata. This finds a function with `name` and executes it
-    /// with the userdata as the first argument.
-    pub fn execute_method<A, R>(&'a self, name: &str, args: A) -> crate::Result<R>
-    where
-        A: IntoLuaVec<'a>,
-        R: FromLua<'a>,
-    {
-        let name = name.to_string();
-        let mt = self.get_metatable()?;
-        let f = mt.get::<_, Function>(name)?;
-        
-        let mut args = args.into_lua_value_vec(self.state)?;
-        args.push_front(self.clone().as_lua(self.state)?);
-
-        f.exec(args)
-    }
-}
-
-impl<'a> FromLuaStack<'a> for AnyUserdata<'a> {
-    unsafe fn from_lua_stack(state: &'a State) -> crate::Result<Self> {
-        ensure_type(state, lua::LUA_TUSERDATA, -1)?;
-
-        Ok(AnyUserdata {
-            state,
-            unsafe_ud: UnsafeUserdata::from_lua_stack(state)?,
-        })
-    }
-}
-
-impl<'a> PushToLuaStack<'a> for AnyUserdata<'a> {
-    unsafe fn push_to_lua_stack(&self, state: &'a State) -> crate::Result<()> {
-        self.unsafe_ud.lref.push_to_lua_stack(state)
-    }
-}
-
-impl<'a> AsLua<'a> for AnyUserdata<'a> {
-    fn as_lua(&self, _lua: &'a State) -> crate::Result<Value<'a>> {
-        Ok(Value::Userdata(self.clone()))
-    }
-}
-
-impl<'a> FromLua<'a> for AnyUserdata<'a> {
-    fn from_lua(_lua: &State, val: Value<'a>) -> crate::Result<Self> {
-        val.into_userdata()
-    }
-}
-
-impl<'a, T: Userdata + 'static> FromLua<'a> for Ref<'a, T> {
-    fn from_lua(_lua: &'a State, val: Value<'a>) -> crate::Result<Self> {
-        let ud = val.into_userdata()?;
-        ud.as_ref::<T>()
-    }
-}
-
-impl<'a, T: Userdata + 'static> FromLua<'a> for RefMut<'a, T> {
-    fn from_lua(_lua: &'a State, val: Value<'a>) -> crate::Result<Self> {
-        let ud = val.into_userdata()?;
-        ud.as_mut::<T>()
-    }
-}