From f5e9287798fa0015d139e74138b8d117a9a4095a Mon Sep 17 00:00:00 2001
From: Quaternions <krakow20@gmail.com>
Date: Thu, 3 Oct 2024 17:20:31 -0700
Subject: [PATCH] weave the thread of fate

lifetime annotations hold &mut Context while scripts are runnable
---
 src/runner/runner.rs | 40 +++++++++++++++++++++++++++++++---------
 1 file changed, 31 insertions(+), 9 deletions(-)

diff --git a/src/runner/runner.rs b/src/runner/runner.rs
index aaa4547..2d44869 100644
--- a/src/runner/runner.rs
+++ b/src/runner/runner.rs
@@ -11,6 +11,7 @@ pub enum Error{
 	},
 	RustLua(mlua::Error),
 	Script(super::instance::GetScriptError),
+	NoContext,
 }
 impl std::fmt::Display for Error{
 	fn fmt(&self,f:&mut std::fmt::Formatter<'_>)->std::fmt::Result{
@@ -42,16 +43,37 @@ impl Runner{
 		init(&runner.lua).map_err(Error::RustLua)?;
 		Ok(runner)
 	}
-	pub fn run_script(&self,script:super::instance::Script,context:&mut Context)->Result<(),Error>{
-		let (name,source)=script.get_name_source(context).map_err(Error::Script)?;
-		self.lua.globals().set("script",script).map_err(Error::RustLua)?;
+	pub fn runnable_context<'a>(self,context:&'a mut Context,services:crate::place::Services)->Result<Runnable<'a>,Error>{
 		//this makes set_app_data shut up about the lifetime
 		self.lua.set_app_data::<&'static mut rbx_dom_weak::WeakDom>(unsafe{core::mem::transmute(&mut context.dom)});
-		let r=self.lua.load(source.as_str())
-		.set_name(name)
-		.exec().map_err(|error|Error::Lua{source,error});
-		self.lua.remove_app_data::<&'static mut rbx_dom_weak::WeakDom>();
-		r?;
-		Ok(())
+		Ok(Runnable{
+			lua:self.lua,
+			_lifetime:&std::marker::PhantomData
+		})
+	}
+}
+
+//Runnable is the same thing but has context set, which it holds the lifetime for.
+pub struct Runnable<'a>{
+	lua:mlua::Lua,
+	_lifetime:&'a std::marker::PhantomData<()>
+}
+impl Runnable<'_>{
+	pub fn drop_context(self)->Runner{
+		self.lua.remove_app_data::<&'static mut rbx_dom_weak::WeakDom>();
+		Runner{
+			lua:self.lua,
+		}
+	}
+	pub fn run_script(&self,script:super::instance::Script)->Result<(),Error>{
+		let (name,source)={
+			let dom=&mut *self.lua.app_data_mut::<&'static mut rbx_dom_weak::WeakDom>().ok_or(Error::NoContext)?;
+			let (name,source)=script.get_name_source(Context::from_mut(dom)).map_err(Error::Script)?;
+			self.lua.globals().set("script",script).map_err(Error::RustLua)?;
+			(name,source)
+		};
+		self.lua.load(source.as_str())
+		.set_name(name)
+		.exec().map_err(|error|Error::Lua{source,error})
 	}
 }