feat(python): switched to a "Promise" approach

chore(python): removed, commented out some of the earlier attempts
feat(python): reworked the logger and tokio runtime approach, now the logging
callback drives the runtime.

dist/py/codemp.pyi

@@ -1,14 +1,24 @@
-from typing import Tuple, Optional
+from typing import Tuple, Optional, Callable
 
-class PyLogger:
+class Driver:
 	"""
-	A python wrapper for the tracing subscriber so that we can
-	receive logging messages from the library.
+	this is akin to a big red button with a white "STOP" on top of it.
+	it is used to stop the runtime
 	"""
-	def __init__(self, debug) -> None: ...
-	async def listen(self) -> Optional[str]: ...
+	def stop(self) -> None: ...
 
 
+def init(logger_cb: Callable, debug: bool) -> Driver: ...
+
+class RustPromise[T]:
+	"""
+	This is a class akin to a future, which wraps a join handle from a spawned
+	task on the rust side. you may call .pyawait() on this promise to block
+	until we have a result, or return immediately if we already have one.
+	This only goes one way rust -> python.
+	"""
+	def pyawait(self) -> T: ...
+
 class TextChange:
 	"""
 	Editor agnostic representation of a text change, it translate between internal
@@ -84,7 +94,7 @@ class Client:
 	to a server and joining/creating new workspaces
 	"""
 	def __new__(cls, host: str, username: str, password: str) -> None: ...
-	async def join_workspace(self, workspace: str) -> Workspace: ...
+	def join_workspace(self, workspace: str) -> RustPromise: ...
 	def leave_workspace(self, workspace: str) -> bool: ...
 	def get_workspace(self, id: str) -> Workspace: ...
 	def active_workspaces(self) -> list[str]: ...

src/ffi/python/client.rs

@@ -11,25 +11,18 @@ impl Client {
 		tokio().block_on(Client::new(host, username, password))
 	}
 
-	async fn dioboia(&self) {
-		tokio().spawn(async { tracing::info!("dioboia? si dioboia!") });
-	}
-
 	#[pyo3(name = "join_workspace")]
-	async fn pyjoin_workspace(&self, workspace: String) -> crate::Result<Workspace> {
-		// self.join_workspace(workspace).await
+	fn pyjoin_workspace(&self, workspace: String) -> PyResult<super::RustPromise> {
+		tracing::info!("attempting to join the workspace {workspace}");
+
+		// crate::a_sync! { self => self.join_workspace(workspace).await }
 		let rc = self.clone();
-		crate::spawn_future!(rc.join_workspace(workspace))
-			.await
-			.unwrap()
-		// This expands to if spawn_future_allow_threads! is used
-		// tokio()
-		// 	.spawn(super::AllowThreads(Box::pin(async move {
-		// 		rc.join_workspace(workspace).await
-		// 	})))
-		// or if only spawn_future!
-		// tokio()
-		// 	.spawn(async move { rc.join_workspace(workspace).await })
+		Ok(super::RustPromise(Some(tokio().spawn(async move {
+			Ok(rc
+				.join_workspace(workspace)
+				.await
+				.map(|f| Python::with_gil(|py| f.into_py(py)))?)
+		}))))
 	}
 
 	#[pyo3(name = "leave_workspace")]

src/ffi/python/mod.rs

@@ -2,13 +2,6 @@ pub mod client;
 pub mod controllers;
 pub mod workspace;
 
-use std::{
-	future::Future,
-	pin::Pin,
-	sync::OnceLock,
-	task::{Context, Poll},
-};
-
 use crate::{
 	api::{Cursor, TextChange},
 	buffer::Controller as BufferController,
@@ -18,12 +11,14 @@ use crate::{
 use pyo3::prelude::*;
 use pyo3::{
 	exceptions::{PyConnectionError, PyRuntimeError, PySystemError},
-	ffi::PyFunctionObject,
 	types::PyFunction,
 };
-use tokio::sync::watch;
 
+use tokio::sync::{mpsc, oneshot};
+
+// global reference to a current_thread tokio runtime
 pub fn tokio() -> &'static tokio::runtime::Runtime {
+	use std::sync::OnceLock;
 	static RT: OnceLock<tokio::runtime::Runtime> = OnceLock::new();
 	RT.get_or_init(|| {
 		tokio::runtime::Builder::new_current_thread()
@@ -35,51 +30,151 @@ pub fn tokio() -> &'static tokio::runtime::Runtime {
 	})
 }
 
-// workaround to allow the GIL to be released across awaits, waiting on
-// https://github.com/PyO3/pyo3/pull/3610
-struct AllowThreads<F>(F);
+// // workaround to allow the GIL to be released across awaits, waiting on
+// // https://github.com/PyO3/pyo3/pull/3610
+// struct AllowThreads<F>(F);
 
-impl<F> Future for AllowThreads<F>
-where
-	F: Future + Unpin + Send,
-	F::Output: Send,
-{
-	type Output = F::Output;
+// impl<F> Future for AllowThreads<F>
+// where
+// 	F: Future + Unpin + Send,
+// 	F::Output: Send,
+// {
+// 	type Output = F::Output;
 
-	fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
-		let waker = cx.waker();
-		let fut = unsafe { self.map_unchecked_mut(|e| &mut e.0) };
-		Python::with_gil(|py| py.allow_threads(|| fut.poll(&mut Context::from_waker(waker))))
-	}
-}
+// 	fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
+// 		let waker = cx.waker();
+// 		let fut = unsafe { self.map_unchecked_mut(|e| &mut e.0) };
+// 		Python::with_gil(|py| py.allow_threads(|| fut.poll(&mut Context::from_waker(waker))))
+// 	}
+// }
+// #[macro_export]
+// macro_rules! spawn_future_allow_threads {
+// 	($fut:expr) => {
+// 		$crate::ffi::python::tokio().spawn($crate::ffi::python::AllowThreads(Box::pin(
+// 			async move {
+// 				tracing::info!("running future from rust.");
+// 				$fut.await
+// 			},
+// 		)))
+// 	};
+// }
 
 #[macro_export]
 macro_rules! a_sync {
 	($($clone:ident)* => $x:expr) => {
 		{
 			$(let $clone = $clone.clone();)*
-			Ok(Promise(Some($crate::ffi::python::tokio().spawn(async move { $x }))))
+			Ok($crate::ffi::python::RustPromise(Some($crate::ffi::python::tokio().spawn(async move {
+				Ok($x.map(|f| Python::with_gil(|py| f.into_py(py)))?)
+			}))))
 		}
 	};
 }
 
-#[macro_export]
-macro_rules! spawn_future_allow_threads {
-	($fut:expr) => {
-		$crate::ffi::python::tokio().spawn($crate::ffi::python::AllowThreads(Box::pin(
-			async move {
-				tracing::info!("running future from rust.");
-				$fut.await
-			},
-		)))
-	};
+// #[macro_export]
+// macro_rules! spawn_future {
+// 	($fut:expr) => {
+// 		$crate::ffi::python::tokio().spawn(async move { $fut.await })
+// 	};
+// }
+
+#[derive(Debug, Clone)]
+struct LoggerProducer(mpsc::UnboundedSender<String>);
+
+impl std::io::Write for LoggerProducer {
+	fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
+		let _ = self.0.send(String::from_utf8_lossy(buf).to_string()); // ignore: logger disconnected or with full buffer
+		Ok(buf.len())
+	}
+
+	fn flush(&mut self) -> std::io::Result<()> {
+		Ok(())
+	}
 }
 
-#[macro_export]
-macro_rules! spawn_future {
-	($fut:expr) => {
-		$crate::ffi::python::tokio().spawn(async move { $fut.await })
+#[pyclass]
+pub struct Driver(Option<oneshot::Sender<()>>);
+#[pymethods]
+impl Driver {
+	fn stop(&mut self) -> PyResult<()> {
+		match self.0.take() {
+			Some(tx) => {
+				let _ = tx.send(());
+				Ok(())
+			}
+			None => Err(PySystemError::new_err("Runtime was already stopped.")),
+		}
+	}
+}
+#[pyfunction]
+fn init(logging_cb: Py<PyFunction>, debug: bool) -> PyResult<PyObject> {
+	let (tx, mut rx) = mpsc::unbounded_channel();
+	let level = if debug {
+		tracing::Level::DEBUG
+	} else {
+		tracing::Level::INFO
 	};
+
+	let format = tracing_subscriber::fmt::format()
+		.without_time()
+		.with_level(true)
+		.with_target(true)
+		.with_thread_ids(false)
+		.with_thread_names(false)
+		.with_file(false)
+		.with_line_number(false)
+		.with_source_location(false)
+		.compact();
+
+	let log_subscribing = tracing_subscriber::fmt()
+		.with_ansi(false)
+		.event_format(format)
+		.with_max_level(level)
+		.with_writer(std::sync::Mutex::new(LoggerProducer(tx)))
+		.try_init();
+
+	let (rt_stop_tx, rt_stop_rx) = oneshot::channel::<()>();
+
+	match log_subscribing {
+		Ok(_) => {
+			// the runtime is driven by the logger awaiting messages from codemp and echoing them back to
+			// python logger.
+			std::thread::spawn(move || {
+				tokio().block_on(async move {
+					tokio::select! {
+						biased;
+						Some(msg) = rx.recv() => {
+							let _ = Python::with_gil(|py| logging_cb.call1(py, (msg,)));
+						},
+						_ = rt_stop_rx => { todo!() },
+					}
+				})
+			});
+			Ok(Python::with_gil(|py| Driver(Some(rt_stop_tx)).into_py(py)))
+		}
+		Err(_) => Err(PyRuntimeError::new_err("codemp was already initialised.")),
+	}
+}
+
+#[pyclass]
+pub struct RustPromise(Option<tokio::task::JoinHandle<PyResult<PyObject>>>);
+
+#[pymethods]
+impl RustPromise {
+	#[pyo3(name = "pyawait")]
+	fn _await(&mut self) -> PyResult<PyObject> {
+		match self.0.take() {
+			None => Err(PySystemError::new_err(
+				"promise can't be awaited multiple times!",
+			)),
+			Some(x) => match tokio().block_on(x) {
+				Err(e) => Err(PySystemError::new_err(format!(
+					"error awaiting promise: {e}"
+				))),
+				Ok(res) => res,
+			},
+		}
+	}
 }
 
 impl From<crate::Error> for PyErr {
@@ -105,90 +200,10 @@ impl IntoPy<PyObject> for crate::api::User {
 	}
 }
 
-#[derive(Debug, Clone)]
-struct LoggerProducer(watch::Sender<String>);
-
-impl std::io::Write for LoggerProducer {
-	fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
-		let _ = self.0.send(String::from_utf8_lossy(buf).to_string()); // ignore: logger disconnected or with full buffer
-		Ok(buf.len())
-	}
-
-	fn flush(&mut self) -> std::io::Result<()> {
-		Ok(())
-	}
-}
-
-#[pyclass]
-struct PyLogger(watch::Receiver<String>);
-
-#[pymethods]
-impl PyLogger {
-	#[new]
-	fn init_logger(debug: bool) -> PyResult<Self> {
-		let (tx, mut rx) = watch::channel("logger initialised".to_string());
-		let level = if debug {
-			tracing::Level::DEBUG
-		} else {
-			tracing::Level::INFO
-		};
-
-		let format = tracing_subscriber::fmt::format()
-			.without_time()
-			.with_level(true)
-			.with_target(true)
-			.with_thread_ids(false)
-			.with_thread_names(false)
-			.with_file(false)
-			.with_line_number(false)
-			.with_source_location(false)
-			.compact();
-
-		match tracing_subscriber::fmt()
-			.with_ansi(false)
-			.event_format(format)
-			.with_max_level(level)
-			.with_writer(std::sync::Mutex::new(LoggerProducer(tx)))
-			.try_init()
-		{
-			Ok(_) => Ok(PyLogger(rx)),
-			Err(_) => Err(PySystemError::new_err("A logger already exists")),
-		}
-	}
-
-	async fn listen(&mut self) -> Option<String> {
-		if self.0.changed().await.is_ok() {
-			return Some(self.0.borrow().clone());
-		}
-
-		None
-	}
-}
-
-#[pyclass]
-pub struct Promise(Option<tokio::task::JoinHandle<PyResult<PyObject>>>);
-
-#[pymethods]
-impl Promise {
-	#[pyo3(name = "await")]
-	fn a_wait(&mut self) -> PyResult<PyObject> {
-		match self.0.take() {
-			None => Err(PySystemError::new_err(
-				"promise can't be awaited multiple times!",
-			)),
-			Some(x) => match tokio().block_on(x) {
-				Err(e) => Err(PySystemError::new_err(format!(
-					"error awaiting promise: {e}"
-				))),
-				Ok(res) => res,
-			},
-		}
-	}
-}
-
 #[pymodule]
 fn codemp(m: &Bound<'_, PyModule>) -> PyResult<()> {
-	m.add_class::<PyLogger>()?;
+	m.add_function(wrap_pyfunction!(init, m)?)?;
+	m.add_class::<Driver>()?;
 
 	m.add_class::<TextChange>()?;
 	m.add_class::<BufferController>()?;

src/ffi/python/workspace.rs

@@ -5,7 +5,7 @@ use pyo3::prelude::*;
 
 use crate::spawn_future;
 
-use super::Promise;
+// use super::Promise;
 
 #[pymethods]
 impl Workspace {
@@ -31,12 +31,12 @@ impl Workspace {
 		}
 	}
 
-	#[pyo3(name = "event")]
-	fn pyevent(&self) -> Promise {
-		crate::a_sync! { self =>
-			self.event().await
-		}
-	}
+	// #[pyo3(name = "event")]
+	// fn pyevent(&self) -> Promise {
+	// 	crate::a_sync! { self =>
+	// 		self.event().await
+	// 	}
+	// }
 
 	#[pyo3(name = "fetch_buffers")]
 	async fn pyfetch_buffers(&self) -> crate::Result<()> {