feat(lua): hand rolled a_sync! to the rescue

Cargo.toml

@@ -26,10 +26,10 @@ tokio-stream = "0.1"
 dashmap = "5.5"
 
 # glue (multiple)
-lazy_static = { version = "1.4", optional = true }
 tracing-subscriber = { version = "0.3", optional = true }
 
 # glue (java)
+lazy_static = { version = "1.4", optional = true }
 jni = { version = "0.21", features = ["invocation"], optional = true }
 
 # glue (lua)
@@ -51,7 +51,7 @@ pyo3-build-config = { version = "0.19", optional = true }
 
 [features]
 default = []
-lua = ["mlua", "lazy_static", "tracing-subscriber"]
+lua = ["mlua", "tracing-subscriber"]
 java = ["lazy_static", "jni", "tracing-subscriber"]
 js = ["napi-build", "tracing-subscriber", "napi", "napi-derive"]
 python = ["pyo3", "pyo3-asyncio", "tracing-subscriber", "pyo3-build-config"]

src/ffi/lua.rs

@@ -17,13 +17,70 @@ impl From::<CodempError> for LuaError {
 	}
 }
 
-lazy_static::lazy_static!{
+fn tokio() -> &'static tokio::runtime::Runtime {
-	static ref RT : tokio::runtime::Runtime = tokio::runtime::Builder::new_current_thread().enable_all().build().expect("could not create tokio runtime");
+	use std::sync::OnceLock;
+	static RT: OnceLock<tokio::runtime::Runtime> = OnceLock::new();
+	RT.get_or_init(||
+		tokio::runtime::Builder::new_current_thread()
+			.enable_all()
+			.build()
+			.expect("could not create tokio runtime")
+	)
+}
+
+struct Promise<T: Send + Sync + IntoLuaMulti>(Option<tokio::task::JoinHandle<LuaResult<T>>>);
+
+impl<T: Send + Sync + IntoLuaMulti + 'static> LuaUserData for Promise<T> {
+	fn add_fields<'a, F: LuaUserDataFields<'a, Self>>(fields: &mut F) {
+		fields.add_field_method_get("ready", |_, this|
+			Ok(this.0.as_ref().map_or(true, |x| x.is_finished()))
+		);
+	}
+
+	fn add_methods<'a, M: LuaUserDataMethods<'a, Self>>(methods: &mut M) {
+		// TODO: await MUST NOT be used in callbacks!!
+		methods.add_method_mut("await", |_, this, ()| match this.0.take() {
+			None => Err(LuaError::runtime("Promise already awaited")),
+			Some(x) => {
+				tokio()
+					.block_on(x)
+					.map_err(LuaError::runtime)?
+			},
+		});
+		methods.add_method_mut("and_then", |_, this, (cb,):(LuaFunction,)| match this.0.take() {
+			None => Err(LuaError::runtime("Promise already awaited")),
+			Some(x) => {
+				tokio()
+					.spawn(async move {
+						match x.await {
+							Err(e) => tracing::error!("could not join promise to run callback: {e}"),
+							Ok(Err(e)) => tracing::error!("promise returned error: {e}"),
+							Ok(Ok(res)) => {
+								if let Err(e) = cb.call::<T,()>(res) {
+									tracing::error!("error running promise callback: {e}");
+								}
+							},
+						}
+					});
+				Ok(())
+			},
+		});
+	}
+}
+
+macro_rules! a_sync {
+	($($clone:ident)* => $x:expr) => {
+		{
+			$(let $clone = $clone.clone();)*
+			Ok(Promise(Some(tokio().spawn(async move { $x }))))
+		}
+	};
 }
 
 fn runtime_drive_forever(_: &Lua, ():()) -> LuaResult<Driver> {
 	let (tx, mut rx) = tokio::sync::mpsc::unbounded_channel();
-	std::thread::spawn(move || RT.block_on(async move {
+	std::thread::spawn(move || tokio().block_on(async move {
+		tracing::info!(" :: driving runtime...");
 		tokio::select! {
 			() = std::future::pending::<()>() => {},
 			_ = rx.recv() => {},
@@ -52,12 +109,12 @@ impl LuaUserData for CodempClient {
 
 		// join a remote workspace and start processing cursor events
 		methods.add_method("join_workspace", |_, this, (session,):(String,)|
-			Ok(RT.block_on(async { this.join_workspace(&session).await })?)
+			a_sync! { this => Ok(this.join_workspace(&session).await?) }
 		);
 
-		methods.add_method("leave_workspace", |_, this, (session,):(String,)| {
+		methods.add_method("leave_workspace", |_, this, (session,):(String,)|
 			Ok(this.leave_workspace(&session))
-		});
+		);
 		
 		methods.add_method("get_workspace", |_, this, (session,):(String,)| Ok(this.get_workspace(&session)));
 		methods.add_method("active_workspaces", |_, this, ()| Ok(this.active_workspaces()));
@@ -69,28 +126,46 @@ impl LuaUserData for CodempClient {
 impl LuaUserData for CodempWorkspace {
 	fn add_methods<'lua, M: LuaUserDataMethods<'lua, Self>>(methods: &mut M) {
 		methods.add_meta_method(LuaMetaMethod::ToString, |_, this, ()| Ok(format!("{:?}", this)));
-		methods.add_method("create_buffer", |_, this, (name,):(String,)| {
+		methods.add_method("create_buffer", |_, this, (name,):(String,)|
-			Ok(RT.block_on(async { this.create(&name).await })?)
+			a_sync! { this => Ok(this.create(&name).await?) }
-		});
+		);
 
-		methods.add_method("attach", |_, this, (name,):(String,)| {
+		methods.add_method("attach", |_, this, (name,):(String,)|
-			Ok(RT.block_on(async { this.attach(&name).await })?)
+			a_sync! { this => Ok(this.attach(&name).await?) }
-		});
+		);
 
-		methods.add_method("detach", |_, this, (name,):(String,)| {
+		methods.add_method("detach", |_, this, (name,):(String,)|
 			Ok(matches!(this.detach(&name), DetachResult::Detaching | DetachResult::AlreadyDetached))
-		});
+		);
 
-		methods.add_method("delete_buffer", |_, this, (name,):(String,)| {
+		methods.add_method("delete_buffer", |_, this, (name,):(String,)|
-			Ok(RT.block_on(this.delete(&name))?)
+			a_sync! { this => Ok(this.delete(&name).await?) }
-		});
+		);
 
 		methods.add_method("get_buffer", |_, this, (name,):(String,)| Ok(this.buffer_by_name(&name)));
 
-		methods.add_method("event", |_, this, ()| Ok(RT.block_on(this.event())?));
+		methods.add_method("event", |_, this, ()|
+			a_sync! { this => Ok(this.event().await?) }
+		);
 
-		methods.add_method("fetch_buffers", |_, this, ()| Ok(RT.block_on(this.fetch_buffers())?));
+		methods.add_method("fetch_buffers", |_, this, ()|
-		methods.add_method("fetch_users", |_, this, ()| Ok(RT.block_on(this.fetch_users())?));
+			a_sync! { this => Ok(this.fetch_buffers().await?) }
+		);
+		methods.add_method("fetch_users", |_, this, ()|
+			a_sync! { this => Ok(this.fetch_users().await?) }
+		);
+
+		methods.add_method("callback", |_, this, (cb,):(LuaFunction,)| {
+			let _this = this.clone();
+			tokio().spawn(async move {
+				while let Ok(ev) = _this.event().await {
+					if let Err(e) = cb.call::<CodempEvent,()>(ev) {
+						tracing::error!("error running workspace callback: {e}");
+					}
+				}
+			});
+			Ok(())
+		});
 	}
 
 	fn add_fields<'lua, F: LuaUserDataFields<'lua, Self>>(fields: &mut F) {
@@ -109,12 +184,12 @@ impl LuaUserData for CodempEvent {
 
 	fn add_fields<'lua, F: LuaUserDataFields<'lua, Self>>(fields: &mut F) {
 		fields.add_field_method_get("type", |_, this| match this {
-			CodempEvent::FileTreeUpdated => Ok("filetree"),
+			CodempEvent::FileTreeUpdated(_) => Ok("filetree"),
 			CodempEvent::UserJoin(_) | CodempEvent::UserLeave(_) => Ok("user"),
 		});
 		fields.add_field_method_get("value", |_, this| match this {
-			CodempEvent::FileTreeUpdated => Ok(None),
+			CodempEvent::FileTreeUpdated(x) => Ok(x.clone()),
-			CodempEvent::UserJoin(x) | CodempEvent::UserLeave(x) => Ok(Some(x.clone())),
+			CodempEvent::UserJoin(x) | CodempEvent::UserLeave(x) => Ok(x.clone()),
 		});
 	}
 }
@@ -123,19 +198,21 @@ impl LuaUserData for CodempCursorController {
 	fn add_methods<'lua, M: LuaUserDataMethods<'lua, Self>>(methods: &mut M) {
 		methods.add_meta_method(LuaMetaMethod::ToString, |_, this, ()| Ok(format!("{:?}", this)));
 
-		methods.add_method("send", |_, this, (buffer, start_row, start_col, end_row, end_col):(String, i32, i32, i32, i32)| {
+		methods.add_method("send", |_, this, (buffer, start_row, start_col, end_row, end_col):(String, i32, i32, i32, i32)|
-			Ok(RT.block_on(this.send(CodempCursor { buffer, start: (start_row, start_col), end: (end_row, end_col), user: None }))?)
+			a_sync! { this => Ok(this.send(CodempCursor { buffer, start: (start_row, start_col), end: (end_row, end_col), user: None }).await?) }
-		});
+		);
-		methods.add_method("try_recv", |_, this, ()| Ok(RT.block_on(this.try_recv())?));
+		methods.add_method("try_recv", |_, this, ()|
-		methods.add_method("recv", |_, this, ()| Ok(RT.block_on(this.recv())?));
+			a_sync! { this => Ok(this.try_recv().await?) }
-		methods.add_method("poll", |_, this, ()| Ok(RT.block_on(this.poll())?));
+		);
+		methods.add_method("recv", |_, this, ()| a_sync! { this => Ok(this.recv().await?) });
+		methods.add_method("poll", |_, this, ()| a_sync! { this => Ok(this.poll().await?) });
 
 		methods.add_method("stop", |_, this, ()| Ok(this.stop()));
 
-		methods.add_method("clear_callback", |_, this, ()| Ok(this.clear_callback()));
+		methods.add_method("clear_callback", |_, this, ()| { this.clear_callback(); Ok(()) });
 		methods.add_method("callback", |_, this, (cb,):(LuaFunction,)| {
-			this.callback(ControllerCallback::from(move |controller| {
+			this.callback(ControllerCallback::from(move |controller: CodempCursorController| {
-				if let Err(e) = cb.call::<(CodempCursorController,), ()>((controller,)) {
+				if let Err(e) = cb.call::<(CodempCursorController,), ()>((controller.clone(),)) {
 					tracing::error!("error running cursor callback: {e}");
 				}
 			}));
@@ -184,33 +261,33 @@ impl LuaUserData for CodempBufferController {
 	fn add_methods<'lua, M: LuaUserDataMethods<'lua, Self>>(methods: &mut M) {
 		methods.add_meta_method(LuaMetaMethod::ToString, |_, this, ()| Ok(format!("{:?}", this)));
 
-		methods.add_method("send", |_, this, (start, end, text): (usize, usize, String)| {
+		methods.add_method("send", |_, this, (start, end, content, hash): (usize, usize, String, Option<i64>)|
-			Ok(
+			a_sync! { this => Ok(
-				RT.block_on(this.send(
+				this.send(
 					CodempTextChange {
 						start: start as u32,
 						end: end as u32,
-						content: text,
+						content,
-						hash: None,
+						hash,
 					}
-				))?
+				).await?
-			)
+			)}
-		});
+		);
 
-		methods.add_method("try_recv", |_, this, ()| Ok(RT.block_on(this.try_recv())?));
+		methods.add_method("try_recv", |_, this, ()| a_sync! { this => Ok(this.try_recv().await?) });
-		methods.add_method("recv", |_, this, ()| Ok(RT.block_on(this.recv())?));
+		methods.add_method("recv", |_, this, ()| a_sync! { this => Ok(this.recv().await?) });
-		methods.add_method("poll", |_, this, ()| Ok(RT.block_on(this.poll())?));
+		methods.add_method("poll", |_, this, ()| a_sync! { this => Ok(this.poll().await?) });
 
 		methods.add_method("stop", |_, this, ()| Ok(this.stop()));
 
-		methods.add_method("content", |_, this, ()| Ok(RT.block_on(this.content())?));
+		methods.add_method("content", |_, this, ()| a_sync! { this => Ok(this.content().await?) });
 
-		methods.add_method("clear_callback", |_, this, ()| Ok(this.clear_callback()));
+		methods.add_method("clear_callback", |_, this, ()| { this.clear_callback(); Ok(()) });
 		methods.add_method("callback", |_, this, (cb,):(LuaFunction,)| {
 			this.callback(move |controller: CodempBufferController| {
 				let _c = controller.clone();
-				if let Err(e) = cb.call::<(CodempBufferController,), ()>((controller,)) {
+				if let Err(e) = cb.call::<(CodempBufferController,), ()>((_c,)) {
-					tracing::error!("error running buffer#{} callback: {e}", _c.name());
+					tracing::error!("error running buffer#{} callback: {e}", controller.name());
 				}
 			});
 			Ok(())
@@ -240,7 +317,7 @@ fn codemp_lua(lua: &Lua) -> LuaResult<LuaTable> {
 
 	// entrypoint
 	exports.set("connect", lua.create_function(|_, (host, username, password):(String,String,String)|
-		Ok(RT.block_on(CodempClient::new(host, username, password))?)
+		a_sync! { => Ok(CodempClient::new(host, username, password).await?) }
 	)?)?;
 
 	// utils
@@ -318,7 +395,7 @@ fn logger(_: &Lua, (printer, debug): (LuaValue, Option<bool>)) -> LuaResult<bool
 				.try_init()
 				.is_ok();
 			if res {
-				RT.spawn(async move {
+				tokio().spawn(async move {
 					while let Some(msg) = rx.recv().await {
 						let _ = cb.call::<(String,),()>((msg,));
 						// if the logger fails logging who logs it?