lafere 0.2.0-pre.6

//!
//!

pub(crate) mod handler;
mod receiver;
mod sender;

use crate::error::{StreamError, TaskError};
use crate::util::watch;

use tokio::sync::{mpsc, oneshot};
use tokio::task::JoinHandle;

pub use receiver::Receiver;
pub use sender::Sender;

/// Used in Client and Server
pub(crate) enum SendBack<P> {
	None,
	Packet(P),
	Close,
	CloseWithPacket,
}

/// A Handle to a background task, if this handle is dropped
/// the connection will be dropped.
#[derive(Debug)]
pub(crate) struct TaskHandle {
	pub close: oneshot::Sender<()>,
	pub task: JoinHandle<Result<(), TaskError>>,
}

impl TaskHandle {
	/// Wait until the connection is closed.
	pub async fn closed(&mut self) {
		self.close.closed().await;
	}

	/// Wait until the connection has nothing more todo which will then close
	/// the connection.
	pub async fn wait(self) -> Result<(), TaskError> {
		self.task.await.map_err(TaskError::Join)?
	}

	/// Send a close signal to the background task and wait until it closes.
	pub async fn close(self) -> Result<(), TaskError> {
		let _ = self.close.send(());
		self.task.await.map_err(TaskError::Join)?
	}

	// used for testing
	#[cfg(test)]
	pub fn abort(self) {
		self.task.abort();
	}
}

/// A sender of packets to an open stream.
#[derive(Debug, Clone)]
pub struct StreamSender<P> {
	pub(crate) inner: mpsc::Sender<P>,
}

impl<P> StreamSender<P> {
	pub(crate) fn new(inner: mpsc::Sender<P>) -> Self {
		Self { inner }
	}

	/// Sends a packet to the client or the server.
	pub async fn send(&self, packet: P) -> Result<(), StreamError> {
		self.inner
			.send(packet)
			.await
			.map_err(|_| StreamError::StreamAlreadyClosed)
	}
}

/// A stream of packets which is inside of a connection.
#[derive(Debug)]
pub struct StreamReceiver<P> {
	pub(crate) inner: mpsc::Receiver<P>,
}

impl<P> StreamReceiver<P> {
	pub(crate) fn new(inner: mpsc::Receiver<P>) -> Self {
		Self { inner }
	}

	/// If none is returned this can mean that the connection
	/// was closed or the other side is finished sending.
	pub async fn receive(&mut self) -> Option<P> {
		self.inner.recv().await
	}

	/// Marks the stream as closed but allows to receive the remaining
	/// messages.
	pub fn close(&mut self) {
		self.inner.close();
	}
}

#[derive(Debug)]
pub struct Configurator<C> {
	inner: watch::Sender<C>,
}

impl<C> Clone for Configurator<C> {
	fn clone(&self) -> Self {
		Self {
			inner: self.inner.clone(),
		}
	}
}

impl<C> Configurator<C> {
	pub(crate) fn new(cfg: C) -> (Self, watch::Receiver<C>) {
		let (tx, rx) = watch::channel(cfg);
		(Self { inner: tx }, rx)
	}

	/// It is possible that there are no receivers left.
	///
	/// This is not checked
	pub fn update(&self, cfg: C) {
		self.inner.send(cfg);
	}

	pub fn read(&self) -> C
	where
		C: Clone,
	{
		self.inner.newest()
	}
}