associated values store (dumb)

src/runner/instance.rs

@@ -9,6 +9,7 @@ use super::vector3::Vector3;
 pub fn set_globals(lua:&mlua::Lua,globals:&mlua::Table)->Result<(),mlua::Error>{
 	//class functions store
 	lua.set_app_data(ClassMethodsStore::default());
+	lua.set_app_data(InstanceValueStore::default());
 
 	let instance_table=lua.create_table()?;
 
@@ -30,7 +31,7 @@ pub fn set_globals(lua:&mlua::Lua,globals:&mlua::Table)->Result<(),mlua::Error>{
 }
 
 // LMAO look at this function!
-fn dom_mut<T>(lua:&mlua::Lua,mut f:impl FnMut(&mut WeakDom)->mlua::Result<T>)->mlua::Result<T>{
+pub fn dom_mut<T>(lua:&mlua::Lua,mut f:impl FnMut(&mut WeakDom)->mlua::Result<T>)->mlua::Result<T>{
 	let mut dom=lua.app_data_mut::<&'static mut WeakDom>().ok_or(mlua::Error::runtime("DataModel missing"))?;
 	f(&mut *dom)
 }
@@ -271,6 +272,17 @@ impl mlua::UserData for Instance{
 				})?{
 					return function.into_lua(lua);
 				}
+
+				//find or create an associated userdata object
+				if let Some(value)=instance_value_store_mut(lua,|ivs|{
+					//TODO: walk class tree somehow
+					match ivs.get_or_create_instance_values(&instance){
+						Some(mut instance_values)=>instance_values.get_or_create_value(lua,index_str),
+						None=>Ok(None)
+					}
+				})?{
+					return value.into_lua(lua);
+				}
 				//find a child with a matching name
 				find_first_child(dom,instance,index_str)
 				.map(|instance|Instance::new(instance.referent()))
@@ -481,3 +493,59 @@ fn find_virtual_property(
 	//Transform Source property with provided function
 	(virtual_property.pointer)(variant)
 }
+
+// lazy-loaded per-instance userdata values
+// This whole thing is a bad idea and a garbage collection nightmare.
+// TODO: recreate rbx_dom_weak with my own instance type that owns this data.
+type CreateUserData=fn(&mlua::Lua)->mlua::Result<mlua::AnyUserData>;
+type LUD=phf::Map<&'static str,// Class name
+	phf::Map<&'static str,// Value name
+		CreateUserData
+	>
+>;
+static LAZY_USER_DATA:LUD=phf::phf_map!{
+};
+#[derive(Default)]
+pub struct InstanceValueStore{
+	values:HashMap<Ref,
+		HashMap<&'static str,
+			mlua::AnyUserData
+		>
+	>,
+}
+pub struct InstanceValues<'a>{
+	named_values:&'static phf::Map<&'static str,CreateUserData>,
+	values:&'a mut HashMap<&'static str,mlua::AnyUserData>,
+}
+impl InstanceValueStore{
+	pub fn get_or_create_instance_values(&mut self,instance:&rbx_dom_weak::Instance)->Option<InstanceValues>{
+		LAZY_USER_DATA.get(instance.class.as_str())
+			.map(|named_values|
+				InstanceValues{
+					named_values,
+					values:self.values.entry(instance.referent())
+					.or_insert_with(||HashMap::new()),
+				}
+			)
+	}
+}
+impl InstanceValues<'_>{
+	pub fn get_or_create_value(&mut self,lua:&mlua::Lua,index:&str)->mlua::Result<Option<mlua::AnyUserData>>{
+		Ok(match self.named_values.get_entry(index){
+			Some((&static_index_str,&function_pointer))=>Some(
+				match self.values.entry(static_index_str){
+					Entry::Occupied(entry)=>entry.get().clone(),
+					Entry::Vacant(entry)=>entry.insert(
+						function_pointer(lua)?
+					).clone(),
+				}
+			),
+			None=>None,
+		})
+	}
+}
+
+pub fn instance_value_store_mut<T>(lua:&mlua::Lua,mut f:impl FnMut(&mut InstanceValueStore)->mlua::Result<T>)->mlua::Result<T>{
+	let mut cf=lua.app_data_mut::<InstanceValueStore>().ok_or(mlua::Error::runtime("InstanceValueStore missing"))?;
+	f(&mut *cf)
+}