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#[cfg(test)]
mod test;
use super::Handle;
use crate::core::{
ChannelCookie, ChannelEnd, Deserialize, DeserializeError, Deserializer, Serialize,
SerializeError, SerializedValue, Serializer,
};
use crate::error::Error;
#[cfg(feature = "sink")]
use crate::handle::CloseChannelEndFuture;
use futures_channel::{mpsc, oneshot};
use futures_core::stream::{FusedStream, Stream};
use std::future;
use std::marker::PhantomData;
use std::mem;
use std::num::NonZeroU32;
use std::pin::Pin;
use std::task::{Context, Poll};
const LOW_CAPACITY: u32 = 4;
/// A sender that is not bound to any particular client.
///
/// [`UnboundSender`s](Self) are used to transfer senders to some other client, typically by
/// returning them from function calls.
///
/// When [creating a channel](Handle::create_channel_with_claimed_receiver) the resulting
/// [`UnclaimedSender`] can be [unbound](UnclaimedSender::unbind) and sent to another client.
///
/// It is worth noting that this type implements [`Copy`] and [`Clone`]. As such (and because it is
/// not bound to any client), it will not close the sending end of a channel. This is the main
/// difference from `UnclaimedSender`.
#[derive(Debug, Copy, Clone, PartialEq, Eq)]
pub struct UnboundSender<T: Serialize + ?Sized> {
cookie: ChannelCookie,
phantom: PhantomData<fn(T)>,
}
impl<T: Serialize + ?Sized> UnboundSender<T> {
fn new(cookie: ChannelCookie) -> Self {
Self {
cookie,
phantom: PhantomData,
}
}
/// Binds the sender to a client.
///
/// See also [`claim`](Self::claim) to bind and claim the sender in one step.
///
/// # Examples
///
/// ```
/// use aldrin::{UnclaimedSender, Sender};
///
/// # use aldrin_test::tokio::TestBroker;
/// # #[tokio::main]
/// # async fn main() -> Result<(), Box<dyn std::error::Error>> {
/// # let broker = TestBroker::new();
/// # let handle = broker.add_client().await;
/// # let (sender, receiver) = handle.create_channel_with_claimed_receiver::<u32>(16).await?;
/// # let sender = sender.unbind();
/// // Assume this sender has been returned from some function call.
/// // let sender: UnboundSender<u32> = ...
///
/// // Bind it to the local client. The explicit type is shown here only for the sake of the
/// // example.
/// let sender: UnclaimedSender<u32> = sender.bind(handle.clone());
///
/// // Afterwards, it can be claimed.
/// let sender: Sender<u32> = sender.claim().await?;
/// # Ok(())
/// # }
pub fn bind(self, client: Handle) -> UnclaimedSender<T> {
UnclaimedSender::new(UnclaimedSenderInner::new(self.cookie, client))
}
/// Binds the sender to a client and claims it.
///
/// This function is equivalent to `sender.bind(client).claim()`.
///
/// See [`UnclaimedSender::claim`] for explanation of the cases in which this function can fail.
///
/// # Examples
///
/// ```
/// use aldrin::Sender;
///
/// # use aldrin_test::tokio::TestBroker;
/// # #[tokio::main]
/// # async fn main() -> Result<(), Box<dyn std::error::Error>> {
/// # let broker = TestBroker::new();
/// # let handle = broker.add_client().await;
/// # let (sender, receiver) = handle.create_channel_with_claimed_receiver::<u32>(16).await?;
/// # let sender = sender.unbind();
/// // Assume this sender has been returned from some function call.
/// // let sender: UnboundSender<u32> = ...
///
/// // Bind it to the local client and claim it, so that it can immediately be used. The
/// // explicit type here is given only for the sake of the example.
/// let sender: Sender<u32> = sender.claim(handle.clone()).await?;
/// # Ok(())
/// # }
pub async fn claim(self, client: Handle) -> Result<Sender<T>, Error> {
self.bind(client).claim().await
}
/// Casts the item type to a different type.
pub fn cast<U: Serialize + ?Sized>(self) -> UnboundSender<U> {
UnboundSender {
cookie: self.cookie,
phantom: PhantomData,
}
}
}
impl<T: Serialize + ?Sized> Serialize for UnboundSender<T> {
fn serialize(&self, serializer: Serializer) -> Result<(), SerializeError> {
serializer.serialize_sender(self.cookie);
Ok(())
}
}
impl<T: Serialize + ?Sized> Deserialize for UnboundSender<T> {
fn deserialize(deserializer: Deserializer) -> Result<Self, DeserializeError> {
deserializer.deserialize_sender().map(Self::new)
}
}
/// A sender that hasn't been claimed yet.
///
/// [`UnclaimedSender`s](Self) are similar to [`UnboundSender`s](UnboundSender) in that they
/// identify the sending end of a channel in an unclaimed state. This sender is however bound to a
/// client and can thus be claimed.
#[derive(Debug)]
pub struct UnclaimedSender<T: Serialize + ?Sized> {
inner: UnclaimedSenderInner,
phantom: PhantomData<fn(T)>,
}
impl<T: Serialize + ?Sized> UnclaimedSender<T> {
pub(crate) fn new(inner: UnclaimedSenderInner) -> Self {
Self {
inner,
phantom: PhantomData,
}
}
/// Returns a handle to the client that was used to create the sender.
///
/// `None` will be returned if the sender is closed.
pub fn client(&self) -> Option<&Handle> {
self.inner.client()
}
/// Unbinds the sender from its client.
///
/// When creating a channel, one end will already be claimed while the other end won't. In order
/// to send that other end (here the sender) to another client, it must first be unbound from
/// its client.
///
/// # Examples
///
/// ```
/// # use aldrin_test::tokio::TestBroker;
/// # #[tokio::main]
/// # async fn main() -> Result<(), Box<dyn std::error::Error>> {
/// # let broker = TestBroker::new();
/// # let handle = broker.add_client().await;
/// // Create a channel with an unclaimed sender and a claimed receiver.
/// let (sender, receiver) = handle.create_channel_with_claimed_receiver::<u32>(16).await?;
///
/// // Unbind the sender so that it can be sent to another client. This will typically happen by
/// // returning it from a function call.
/// let sender = sender.unbind();
/// # Ok(())
/// # }
pub fn unbind(self) -> UnboundSender<T> {
UnboundSender::new(self.inner.unbind())
}
/// Closes the sender without consuming it.
///
/// This closes the sender such that it cannot be claimed anymore by any client. When the
/// receiver waits for the channel to become [established](PendingReceiver::established), an
/// error will be returned.
///
/// After closing a sender, any further function calls will return [`Error::InvalidChannel`].
///
/// # Examples
///
/// ```
/// use aldrin::Error;
/// # use aldrin_test::tokio::TestBroker;
///
/// # #[tokio::main]
/// # async fn main() -> Result<(), Box<dyn std::error::Error>> {
/// # let broker = TestBroker::new();
/// # let handle = broker.add_client().await;
/// let (mut sender, receiver) = handle.create_channel_with_claimed_receiver::<u32>(16).await?;
///
/// // Close the sender.
/// sender.close().await?;
///
/// // For the receiver, an error will be returned when waiting for the channel to become
/// // established.
/// let err = receiver.established().await.unwrap_err();
/// assert_eq!(err, Error::InvalidChannel);
/// # Ok(())
/// # }
pub async fn close(&mut self) -> Result<(), Error> {
self.inner.close().await
}
/// Claims the sender by its bound client.
///
/// When creating channels, both ends must be claimed by a client before items can be sent and
/// received. One end will always be claimed automatically. The other end, here the sender, must
/// be claimed manually (after it has possibly been sent to another client).
///
/// When this function returns successfully, a receiver's call to
/// [`PendingReceiver::established`] will also resolve successfully.
///
/// This function can fail in the following cases:
/// - Some other client has already claimed the sender.
/// - Some other client has closed the sender.
/// - The receiver has been closed.
///
/// # Examples
///
/// ```
/// # use aldrin_test::tokio::TestBroker;
///
/// # #[tokio::main]
/// # async fn main() -> Result<(), Box<dyn std::error::Error>> {
/// # let broker = TestBroker::new();
/// # let handle = broker.add_client().await;
/// // The sender is unclaimed, while the receiver has been claimed automatically.
/// let (sender, receiver) = handle.create_channel_with_claimed_receiver(16).await?;
///
/// // Claim the sender.
/// let mut sender = sender.claim().await?;
///
/// // This will now resolve immediately.
/// let mut receiver = receiver.established().await?;
///
/// // The channel is now fully established and items can be sent and received.
/// sender.send_item(&1).await?;
/// sender.send_item(&2).await?;
/// assert_eq!(receiver.next_item().await, Ok(Some(1)));
/// assert_eq!(receiver.next_item().await, Ok(Some(2)));
/// # Ok(())
/// # }
pub async fn claim(self) -> Result<Sender<T>, Error> {
self.inner.claim().await.map(Sender::new)
}
/// Casts the item type to a different type.
pub fn cast<U: Serialize + ?Sized>(self) -> UnclaimedSender<U> {
UnclaimedSender {
inner: self.inner,
phantom: PhantomData,
}
}
}
#[derive(Debug)]
pub(crate) struct UnclaimedSenderInner {
cookie: ChannelCookie,
client: Option<Handle>,
}
impl UnclaimedSenderInner {
pub(crate) fn new(cookie: ChannelCookie, client: Handle) -> Self {
Self {
cookie,
client: Some(client),
}
}
fn client(&self) -> Option<&Handle> {
self.client.as_ref()
}
fn unbind(mut self) -> ChannelCookie {
self.client = None;
self.cookie
}
async fn close(&mut self) -> Result<(), Error> {
if let Some(client) = self.client.take() {
client
.close_channel_end(self.cookie, ChannelEnd::Sender, false)?
.await
} else {
Ok(())
}
}
async fn claim(mut self) -> Result<SenderInner, Error> {
let client = self.client.take().ok_or(Error::InvalidChannel)?;
client.claim_sender(self.cookie).await
}
}
impl Drop for UnclaimedSenderInner {
fn drop(&mut self) {
if let Some(client) = self.client.take() {
client
.close_channel_end(self.cookie, ChannelEnd::Sender, false)
.ok();
}
}
}
/// A claimed sender that is waiting for the channel to become established.
///
/// [`PendingSender`s](Self) are used to wait until some client has claimed the receiving end of the
/// channel. This is done with the [`established`](Self::established) function.
#[derive(Debug)]
pub struct PendingSender<T: Serialize + ?Sized> {
inner: PendingSenderInner,
phantom: PhantomData<fn(T)>,
}
impl<T: Serialize + ?Sized> PendingSender<T> {
pub(crate) fn new(inner: PendingSenderInner) -> Self {
Self {
inner,
phantom: PhantomData,
}
}
/// Returns a handle to the client that was used to create the sender.
///
/// `None` will be returned if the sender is closed.
pub fn client(&self) -> Option<&Handle> {
self.inner.client()
}
/// Closes the sender without consuming it.
///
/// When closing a [`PendingSender`], it will no longer be possible to claim the receiver. If it
/// has already been claimed, then it will receive `None`, indicating that the channel has been
/// closed.
///
/// # Examples
///
/// ## Closing a sender while the receiver hasn't been claimed yet
///
/// ```
/// use aldrin::Error;
/// # use aldrin_test::tokio::TestBroker;
///
/// # #[tokio::main]
/// # async fn main() -> Result<(), Box<dyn std::error::Error>> {
/// # let broker = TestBroker::new();
/// # let handle = broker.add_client().await;
/// let (mut sender, receiver) = handle.create_channel_with_claimed_sender::<u32>().await?;
///
/// // Close the sender.
/// sender.close().await?;
///
/// // For the receiver, an error will be returned when trying to claim it.
/// let err = receiver.claim(16).await.unwrap_err();
/// assert_eq!(err, Error::InvalidChannel);
/// # Ok(())
/// # }
/// ```
///
/// ## Closing a sender while the receiver has already been claimed
///
/// ```
/// use aldrin::Error;
/// # use aldrin_test::tokio::TestBroker;
///
/// # #[tokio::main]
/// # async fn main() -> Result<(), Box<dyn std::error::Error>> {
/// # let broker = TestBroker::new();
/// # let handle = broker.add_client().await;
/// let (mut sender, receiver) = handle.create_channel_with_claimed_sender::<u32>().await?;
///
/// // Claim the receiver.
/// let mut receiver = receiver.claim(16).await?;
///
/// // Close the sender.
/// sender.close().await?;
///
/// // The receiver will receive None.
/// assert_eq!(receiver.next_item().await, Ok(None));
/// # Ok(())
/// # }
/// ```
pub async fn close(&mut self) -> Result<(), Error> {
self.inner.close().await
}
/// Waits until the channel has been established.
///
/// A channel is established when both ends have been claimed. An error is returned when the
/// receiver has been closed instead of claimed.
pub async fn established(self) -> Result<Sender<T>, Error> {
self.inner.established().await.map(Sender::new)
}
/// Casts the item type to a different type.
pub fn cast<U: Serialize + ?Sized>(self) -> PendingSender<U> {
PendingSender {
inner: self.inner,
phantom: PhantomData,
}
}
}
#[derive(Debug)]
pub(crate) struct PendingSenderInner {
cookie: ChannelCookie,
state: Option<PendingSenderInnerState>,
}
#[derive(Debug)]
struct PendingSenderInnerState {
client: Handle,
established: oneshot::Receiver<(u32, mpsc::UnboundedReceiver<u32>)>,
}
impl PendingSenderInner {
pub(crate) fn new(
cookie: ChannelCookie,
client: Handle,
established: oneshot::Receiver<(u32, mpsc::UnboundedReceiver<u32>)>,
) -> Self {
Self {
cookie,
state: Some(PendingSenderInnerState {
client,
established,
}),
}
}
fn client(&self) -> Option<&Handle> {
self.state.as_ref().map(|state| &state.client)
}
async fn close(&mut self) -> Result<(), Error> {
if let Some(state) = self.state.take() {
state
.client
.close_channel_end(self.cookie, ChannelEnd::Sender, true)?
.await
} else {
Ok(())
}
}
async fn established(mut self) -> Result<SenderInner, Error> {
let state = self.state.take().ok_or(Error::InvalidChannel)?;
let client = state.client;
state
.established
.await
.map(|(capacity, capacity_added)| {
SenderInner::new(self.cookie, client, capacity_added, capacity)
})
.map_err(|_| Error::InvalidChannel)
}
}
impl Drop for PendingSenderInner {
fn drop(&mut self) {
if let Some(state) = self.state.take() {
state
.client
.close_channel_end(self.cookie, ChannelEnd::Sender, true)
.ok();
}
}
}
/// The sending end of an established channel.
///
/// This type of sender is obtained when a channel has been fully established, either by
/// [`PendingSender::established`] or by [`UnclaimedSender::claim`].
#[derive(Debug)]
pub struct Sender<T: Serialize + ?Sized> {
inner: SenderInner,
phantom: PhantomData<fn(T)>,
}
impl<T: Serialize + ?Sized> Sender<T> {
pub(crate) fn new(inner: SenderInner) -> Self {
Self {
inner,
phantom: PhantomData,
}
}
/// Casts the item type to a different type.
pub fn cast<U: Serialize + ?Sized>(self) -> Sender<U> {
Sender {
inner: self.inner,
phantom: PhantomData,
}
}
/// Polls the channel for capacity to send at least 1 item.
pub fn poll_send_ready(&mut self, cx: &mut Context) -> Poll<Result<(), Error>> {
self.inner.poll_send_ready(cx)
}
/// Waits until the channel has capacity to send at least 1 item.
pub async fn send_ready(&mut self) -> Result<(), Error> {
future::poll_fn(|cx| self.poll_send_ready(cx)).await
}
/// Sends an item on the channel.
///
/// This function panics if the channel doesn't have any capacity left. You must call either
/// [`send_ready`](Self::send_ready) or [`poll_send_ready`](Self::poll_send_ready) before to
/// ensure there is capacity.
pub fn start_send_item(&mut self, item: &T) -> Result<(), Error> {
self.inner.start_send_item(item)
}
/// Sends an item on the channel.
///
/// This function will wait until the channel has capacity to send at least 1 item.
pub async fn send_item(&mut self, item: &T) -> Result<(), Error> {
self.send_ready().await?;
self.start_send_item(item)
}
/// Closes the sender without consuming it.
///
/// The will cause the receiving end to receive [`None`] after all other items have been
/// received.
///
/// # Examples
///
/// ```
/// # use aldrin_test::tokio::TestBroker;
///
/// # #[tokio::main]
/// # async fn main() -> Result<(), Box<dyn std::error::Error>> {
/// # let broker = TestBroker::new();
/// # let handle = broker.add_client().await;
/// let (sender, receiver) = handle.create_channel_with_claimed_sender().await?;
///
/// let mut receiver = receiver.claim(16).await?;
/// let mut sender = sender.established().await?;
///
/// // Send a couple of items and then close the sender.
/// sender.send_item(&1).await?;
/// sender.send_item(&2).await?;
/// sender.send_item(&3).await?;
/// sender.close().await?;
///
/// // The receiver will receive all items followed by None.
/// assert_eq!(receiver.next_item().await, Ok(Some(1)));
/// assert_eq!(receiver.next_item().await, Ok(Some(2)));
/// assert_eq!(receiver.next_item().await, Ok(Some(3)));
/// assert_eq!(receiver.next_item().await, Ok(None));
/// # Ok(())
/// # }
/// ```
pub async fn close(&mut self) -> Result<(), Error> {
self.inner.close().await
}
/// Returns `true` if the channel is closed.
pub fn is_closed(&self) -> bool {
self.inner.is_closed()
}
/// Polls whether the channel is closed.
pub fn poll_closed(&mut self, cx: &mut Context) -> Poll<()> {
self.inner.poll_closed(cx)
}
/// Completes when the channel is closed.
pub async fn closed(&mut self) {
future::poll_fn(|cx| self.poll_closed(cx)).await
}
}
#[cfg(feature = "sink")]
impl<T: Serialize + ?Sized> futures_sink::Sink<&T> for Sender<T> {
type Error = Error;
fn poll_ready(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<(), Self::Error>> {
self.poll_send_ready(cx)
}
fn start_send(mut self: Pin<&mut Self>, item: &T) -> Result<(), Self::Error> {
self.start_send_item(item)
}
fn poll_flush(self: Pin<&mut Self>, _cx: &mut Context) -> Poll<Result<(), Self::Error>> {
self.inner.poll_flush()
}
fn poll_close(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<(), Self::Error>> {
self.inner.poll_close(cx)
}
}
#[cfg(feature = "sink")]
impl<T: Serialize> futures_sink::Sink<T> for Sender<T> {
type Error = Error;
fn poll_ready(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<(), Self::Error>> {
self.poll_send_ready(cx)
}
fn start_send(mut self: Pin<&mut Self>, item: T) -> Result<(), Self::Error> {
self.start_send_item(&item)
}
fn poll_flush(self: Pin<&mut Self>, _cx: &mut Context) -> Poll<Result<(), Self::Error>> {
self.inner.poll_flush()
}
fn poll_close(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<(), Self::Error>> {
self.inner.poll_close(cx)
}
}
#[derive(Debug)]
pub(crate) struct SenderInner {
cookie: ChannelCookie,
state: SenderInnerState,
}
#[derive(Debug)]
enum SenderInnerState {
Open {
client: Handle,
capacity_added: mpsc::UnboundedReceiver<u32>,
capacity: u32,
},
Closed,
#[cfg(feature = "sink")]
Closing(CloseChannelEndFuture),
}
impl SenderInner {
pub(crate) fn new(
cookie: ChannelCookie,
client: Handle,
capacity_added: mpsc::UnboundedReceiver<u32>,
capacity: u32,
) -> Self {
Self {
cookie,
state: SenderInnerState::Open {
client,
capacity_added,
capacity,
},
}
}
fn poll_send_ready(&mut self, cx: &mut Context) -> Poll<Result<(), Error>> {
let SenderInnerState::Open {
ref mut capacity_added,
ref mut capacity,
..
} = self.state
else {
return Poll::Ready(Err(Error::InvalidChannel));
};
if *capacity == 0 {
loop {
match Pin::new(&mut *capacity_added).poll_next(cx) {
Poll::Ready(Some(added_capacity)) => *capacity += added_capacity,
Poll::Ready(None) => {
self.state = SenderInnerState::Closed;
return Poll::Ready(Err(Error::InvalidChannel));
}
Poll::Pending => {
if *capacity > 0 {
break;
} else {
return Poll::Pending;
}
}
}
}
} else {
match capacity_added.try_next() {
Ok(Some(added_capacity)) => *capacity += added_capacity,
Ok(None) => {
self.state = SenderInnerState::Closed;
return Poll::Ready(Err(Error::InvalidChannel));
}
Err(_) => {}
}
}
Poll::Ready(Ok(()))
}
fn start_send_item<T: Serialize + ?Sized>(&mut self, value: &T) -> Result<(), Error> {
let SenderInnerState::Open {
ref client,
ref mut capacity,
..
} = self.state
else {
return Err(Error::InvalidChannel);
};
debug_assert!(*capacity > 0);
let value = SerializedValue::serialize(value)?;
client.send_item(self.cookie, value)?;
*capacity -= 1;
Ok(())
}
#[cfg(feature = "sink")]
fn poll_flush(&self) -> Poll<Result<(), Error>> {
if let SenderInnerState::Open { .. } = self.state {
Poll::Ready(Ok(()))
} else {
Poll::Ready(Err(Error::InvalidChannel))
}
}
#[cfg(feature = "sink")]
fn poll_close(&mut self, cx: &mut Context) -> Poll<Result<(), Error>> {
use std::future::Future;
let mut fut = match mem::replace(&mut self.state, SenderInnerState::Closed) {
SenderInnerState::Open { client, .. } => {
match client.close_channel_end(self.cookie, ChannelEnd::Sender, true) {
Ok(fut) => fut,
Err(e) => return Poll::Ready(Err(e)),
}
}
SenderInnerState::Closing(fut) => fut,
SenderInnerState::Closed => return Poll::Ready(Ok(())),
};
let res = Pin::new(&mut fut).poll(cx);
if res.is_pending() {
self.state = SenderInnerState::Closing(fut);
}
res
}
async fn close(&mut self) -> Result<(), Error> {
if let SenderInnerState::Open { client, .. } =
mem::replace(&mut self.state, SenderInnerState::Closed)
{
client
.close_channel_end(self.cookie, ChannelEnd::Sender, true)?
.await
} else {
Ok(())
}
}
fn is_closed(&self) -> bool {
matches!(self.state, SenderInnerState::Closed)
}
fn poll_closed(&mut self, cx: &mut Context) -> Poll<()> {
let (capacity_added, capacity) = match self.state {
SenderInnerState::Open {
ref mut capacity_added,
ref mut capacity,
..
} => (capacity_added, capacity),
SenderInnerState::Closed => return Poll::Ready(()),
#[cfg(feature = "sink")]
SenderInnerState::Closing(_) => return self.poll_close(cx).map(|_| ()),
};
loop {
match Pin::new(&mut *capacity_added).poll_next(cx) {
Poll::Ready(Some(added_capacity)) => *capacity += added_capacity,
Poll::Ready(None) => {
self.state = SenderInnerState::Closed;
break Poll::Ready(());
}
Poll::Pending => break Poll::Pending,
}
}
}
}
impl Drop for SenderInner {
fn drop(&mut self) {
if let SenderInnerState::Open { client, .. } =
mem::replace(&mut self.state, SenderInnerState::Closed)
{
client
.close_channel_end(self.cookie, ChannelEnd::Sender, true)
.ok();
}
}
}
/// A receiver that is not bound to any particular client.
///
/// [`UnboundReceiver`s](Self) are used to transfer receivers to some other client, typically by
/// returning them from function calls.
///
/// When [creating a channel](Handle::create_channel_with_claimed_sender) the resulting
/// [`UnclaimedReceiver`] can be [unbound](UnclaimedReceiver::unbind) and sent to another client.
///
/// It is worth noting that this type implements [`Copy`] and [`Clone`]. As such (and because it is
/// not bound to any client), it will not close the receiving end of a channel. This is the main
/// difference from `UnclaimedReceiver`.
#[derive(Debug, Copy, Clone, PartialEq, Eq)]
pub struct UnboundReceiver<T: Deserialize> {
cookie: ChannelCookie,
phantom: PhantomData<fn() -> T>,
}
impl<T: Deserialize> UnboundReceiver<T> {
fn new(cookie: ChannelCookie) -> Self {
Self {
cookie,
phantom: PhantomData,
}
}
/// Binds the receiver to a client.
///
/// See also [`claim`](Self::claim) to bind and claim the receiver in one step.
///
/// # Examples
///
/// ```
/// use aldrin::{Receiver, UnclaimedReceiver};
///
/// # use aldrin_test::tokio::TestBroker;
/// # #[tokio::main]
/// # async fn main() -> Result<(), Box<dyn std::error::Error>> {
/// # let broker = TestBroker::new();
/// # let handle = broker.add_client().await;
/// # let (sender, receiver) = handle.create_channel_with_claimed_sender::<u32>().await?;
/// # let receiver = receiver.unbind();
/// // Assume this receiver has been returned from some function call.
/// // let receiver: UnboundReceiver<u32> = ...
///
/// // Bind it to the local client. The explicit type is shown here only for the sake of the
/// // example.
/// let receiver: UnclaimedReceiver<u32> = receiver.bind(handle.clone());
///
/// // Afterwards, it can be claimed.
/// let receiver: Receiver<u32> = receiver.claim(16).await?;
/// # Ok(())
/// # }
pub fn bind(self, client: Handle) -> UnclaimedReceiver<T> {
UnclaimedReceiver::new(UnclaimedReceiverInner::new(self.cookie, client))
}
/// Binds the receiver to a client and claims it.
///
/// This function is equivalent to `receiver.bind(client).claim()`.
///
/// See [`UnclaimedReceiver::claim`] for explanation of the cases in which this function can
/// fail.
///
/// A `capacity` of 0 is treated as if 1 was specificed instead.
///
/// # Examples
///
/// ```
/// use aldrin::Receiver;
///
/// # use aldrin_test::tokio::TestBroker;
/// # #[tokio::main]
/// # async fn main() -> Result<(), Box<dyn std::error::Error>> {
/// # let broker = TestBroker::new();
/// # let handle = broker.add_client().await;
/// # let (sender, receiver) = handle.create_channel_with_claimed_sender::<u32>().await?;
/// # let receiver = receiver.unbind();
/// // Assume this receiver has been returned from some function call.
/// // let receiver: UnboundReceiver<u32> = ...
///
/// // Bind it to the local client and claim it, so that it can immediately be used. The
/// // explicit type here is given only for the sake of the example.
/// let receiver: Receiver<u32> = receiver.claim(handle.clone(), 16).await?;
/// # Ok(())
/// # }
pub async fn claim(self, client: Handle, capacity: u32) -> Result<Receiver<T>, Error> {
self.bind(client).claim(capacity).await
}
/// Casts the item type to a different type.
pub fn cast<U: Deserialize>(self) -> UnboundReceiver<U> {
UnboundReceiver {
cookie: self.cookie,
phantom: PhantomData,
}
}
}
impl<T: Deserialize> Serialize for UnboundReceiver<T> {
fn serialize(&self, serializer: Serializer) -> Result<(), SerializeError> {
serializer.serialize_receiver(self.cookie);
Ok(())
}
}
impl<T: Deserialize> Deserialize for UnboundReceiver<T> {
fn deserialize(deserializer: Deserializer) -> Result<Self, DeserializeError> {
deserializer.deserialize_receiver().map(Self::new)
}
}
/// A receiver that hasn't been claimed yet.
///
/// [`UnclaimedReceiver`s](Self) are similar to [`UnboundReceiver`s](UnboundReceiver) in that they
/// identify the receiving end of a channel in an unclaimed state. This receiver is however bound to
/// a client and can thus be claimed.
#[derive(Debug)]
pub struct UnclaimedReceiver<T: Deserialize> {
inner: UnclaimedReceiverInner,
phantom: PhantomData<fn() -> T>,
}
impl<T: Deserialize> UnclaimedReceiver<T> {
pub(crate) fn new(inner: UnclaimedReceiverInner) -> Self {
Self {
inner,
phantom: PhantomData,
}
}
/// Returns a handle to the client that was used to create the receiver.
///
/// `None` will be returned if the receiver is closed.
pub fn client(&self) -> Option<&Handle> {
self.inner.client()
}
/// Unbinds the receiver from its client.
///
/// When creating a channel, one end will already be claimed while the other end won't. In order
/// to send that other end (here the receiver) to another client, it must first be unbound from
/// its client.
///
/// # Examples
///
/// ```
/// # use aldrin_test::tokio::TestBroker;
/// # #[tokio::main]
/// # async fn main() -> Result<(), Box<dyn std::error::Error>> {
/// # let broker = TestBroker::new();
/// # let handle = broker.add_client().await;
/// // Create a channel with an unclaimed receiver and a claimed sender.
/// let (sender, receiver) = handle.create_channel_with_claimed_sender::<u32>().await?;
///
/// // Unbind the receiver so that it can be sent to another client. This will typically happen
/// // by returning it from a function call.
/// let receiver = receiver.unbind();
/// # Ok(())
/// # }
pub fn unbind(self) -> UnboundReceiver<T> {
UnboundReceiver::new(self.inner.unbind())
}
/// Closes the receiver without consuming it.
///
/// This closes the receiver such that it cannot be claimed anymore by any client. When the
/// sender waits for the channel to become [established](PendingSender::established), an error
/// will be returned.
///
/// After closing a receiver, any further function calls will return [`Error::InvalidChannel`].
///
/// # Examples
///
/// ```
/// use aldrin::Error;
/// # use aldrin_test::tokio::TestBroker;
///
/// # #[tokio::main]
/// # async fn main() -> Result<(), Box<dyn std::error::Error>> {
/// # let broker = TestBroker::new();
/// # let handle = broker.add_client().await;
/// let (sender, mut receiver) = handle.create_channel_with_claimed_sender::<u32>().await?;
///
/// // Close the receiver.
/// receiver.close().await?;
///
/// // For the sender, an error will be returned when waiting for the channel to become
/// // established.
/// let err = sender.established().await.unwrap_err();
/// assert_eq!(err, Error::InvalidChannel);
/// # Ok(())
/// # }
pub async fn close(&mut self) -> Result<(), Error> {
self.inner.close().await
}
/// Claims the receiver by its bound client.
///
/// When creating channels, both ends must be claimed by a client before items can be sent and
/// received. One end will always be claimed automatically. The other end, here the receiver,
/// must be claimed manually (after it has possibly been sent to another client).
///
/// When this function returns successfully, a senders's call to [`PendingSender::established`]
/// will also resolve successfully.
///
/// This function can fail in the following cases:
/// - Some other client has already claimed the receiver.
/// - Some other client has closed the receiver.
/// - The sender has been closed.
///
/// A `capacity` of 0 is treated as if 1 was specificed instead.
///
/// # Examples
///
/// ```
/// # use aldrin_test::tokio::TestBroker;
///
/// # #[tokio::main]
/// # async fn main() -> Result<(), Box<dyn std::error::Error>> {
/// # let broker = TestBroker::new();
/// # let handle = broker.add_client().await;
/// // The receiver is unclaimed, while the sender has been claimed automatically.
/// let (sender, receiver) = handle.create_channel_with_claimed_sender().await?;
///
/// // Claim the receiver.
/// let mut receiver = receiver.claim(16).await?;
///
/// // This will now resolve immediately.
/// let mut sender = sender.established().await?;
///
/// // The channel is now fully established and items can be sent and received.
/// sender.send_item(&1).await?;
/// sender.send_item(&2).await?;
/// assert_eq!(receiver.next_item().await, Ok(Some(1)));
/// assert_eq!(receiver.next_item().await, Ok(Some(2)));
/// # Ok(())
/// # }
pub async fn claim(self, capacity: u32) -> Result<Receiver<T>, Error> {
self.inner.claim(capacity).await.map(Receiver::new)
}
/// Casts the item type to a different type.
pub fn cast<U: Deserialize>(self) -> UnclaimedReceiver<U> {
UnclaimedReceiver {
inner: self.inner,
phantom: PhantomData,
}
}
}
#[derive(Debug)]
pub(crate) struct UnclaimedReceiverInner {
cookie: ChannelCookie,
client: Option<Handle>,
}
impl UnclaimedReceiverInner {
pub(crate) fn new(cookie: ChannelCookie, client: Handle) -> Self {
Self {
cookie,
client: Some(client),
}
}
fn client(&self) -> Option<&Handle> {
self.client.as_ref()
}
fn unbind(mut self) -> ChannelCookie {
self.client = None;
self.cookie
}
async fn close(&mut self) -> Result<(), Error> {
if let Some(client) = self.client.take() {
client
.close_channel_end(self.cookie, ChannelEnd::Receiver, false)?
.await
} else {
Ok(())
}
}
async fn claim(mut self, capacity: u32) -> Result<ReceiverInner, Error> {
let client = self.client.take().ok_or(Error::InvalidChannel)?;
client.claim_receiver(self.cookie, capacity).await
}
}
impl Drop for UnclaimedReceiverInner {
fn drop(&mut self) {
if let Some(client) = self.client.take() {
client
.close_channel_end(self.cookie, ChannelEnd::Receiver, false)
.ok();
}
}
}
/// A claimed receiver that is waiting for the channel to become established.
///
/// [`PendingReceiver`s](Self) are used to wait until some client has claimed the sending end of the
/// channel. This is done with the [`established`](Self::established) function.
#[derive(Debug)]
pub struct PendingReceiver<T: Deserialize> {
inner: PendingReceiverInner,
phantom: PhantomData<fn() -> T>,
}
impl<T: Deserialize> PendingReceiver<T> {
pub(crate) fn new(inner: PendingReceiverInner) -> Self {
Self {
inner,
phantom: PhantomData,
}
}
/// Returns a handle to the client that was used to create the receiver.
///
/// `None` will be returned if the receiver is closed.
pub fn client(&self) -> Option<&Handle> {
self.inner.client()
}
/// Closes the receiver without consuming it.
///
/// When closing a [`PendingReceiver`], it will no longer be possible to claim the sender.
///
/// When the sender has already been claimed, the situation is a little bit more
/// complicated. The sender is notified asynchronously about the receiver's closing. It will,
/// sooner or later, receive an error when sending an item.
///
/// # Examples
///
/// ## Closing a receiver while the sender hasn't been claimed yet
///
/// ```
/// use aldrin::Error;
/// # use aldrin_test::tokio::TestBroker;
///
/// # #[tokio::main]
/// # async fn main() -> Result<(), Box<dyn std::error::Error>> {
/// # let broker = TestBroker::new();
/// # let handle = broker.add_client().await;
/// let (sender, mut receiver) = handle.create_channel_with_claimed_receiver::<u32>(16).await?;
///
/// // Close the receiver.
/// receiver.close().await?;
///
/// // For the sender, an error will be returned when trying to claim it.
/// let err = sender.claim().await.unwrap_err();
/// assert_eq!(err, Error::InvalidChannel);
/// # Ok(())
/// # }
/// ```
pub async fn close(&mut self) -> Result<(), Error> {
self.inner.close().await
}
/// Waits until the channel has been established.
///
/// A channel is established when both ends have been claimed. An error is returned when the
/// sender has been closed instead of claimed.
pub async fn established(self) -> Result<Receiver<T>, Error> {
self.inner.established().await.map(Receiver::new)
}
/// Casts the item type to a different type.
pub fn cast<U: Deserialize>(self) -> PendingReceiver<U> {
PendingReceiver {
inner: self.inner,
phantom: PhantomData,
}
}
}
#[derive(Debug)]
pub(crate) struct PendingReceiverInner {
cookie: ChannelCookie,
state: Option<PendingReceiverInnerState>,
}
#[derive(Debug)]
struct PendingReceiverInnerState {
client: Handle,
established: oneshot::Receiver<mpsc::UnboundedReceiver<SerializedValue>>,
max_capacity: NonZeroU32,
}
impl PendingReceiverInner {
pub(crate) fn new(
cookie: ChannelCookie,
client: Handle,
established: oneshot::Receiver<mpsc::UnboundedReceiver<SerializedValue>>,
max_capacity: NonZeroU32,
) -> Self {
Self {
cookie,
state: Some(PendingReceiverInnerState {
client,
established,
max_capacity,
}),
}
}
fn client(&self) -> Option<&Handle> {
self.state.as_ref().map(|state| &state.client)
}
async fn close(&mut self) -> Result<(), Error> {
if let Some(state) = self.state.take() {
state
.client
.close_channel_end(self.cookie, ChannelEnd::Receiver, true)?
.await
} else {
Ok(())
}
}
async fn established(mut self) -> Result<ReceiverInner, Error> {
let state = self.state.take().ok_or(Error::InvalidChannel)?;
let client = state.client;
state
.established
.await
.map(|items| ReceiverInner::new(self.cookie, client, items, state.max_capacity))
.map_err(|_| Error::InvalidChannel)
}
}
impl Drop for PendingReceiverInner {
fn drop(&mut self) {
if let Some(state) = self.state.take() {
state
.client
.close_channel_end(self.cookie, ChannelEnd::Receiver, true)
.ok();
}
}
}
/// The receiving end of an established channel.
///
/// This type of receiver is obtained when a channel has been fully established, either by
/// [`PendingReceiver::established`] or by [`UnclaimedReceiver::claim`].
#[derive(Debug)]
pub struct Receiver<T: Deserialize> {
inner: ReceiverInner,
phantom: PhantomData<fn() -> T>,
}
impl<T: Deserialize> Receiver<T> {
pub(crate) fn new(inner: ReceiverInner) -> Self {
Self {
inner,
phantom: PhantomData,
}
}
/// Closes the receiver without consuming it.
pub async fn close(&mut self) -> Result<(), Error> {
self.inner.close().await
}
/// Casts the item type to a different type.
pub fn cast<U: Deserialize>(self) -> Receiver<U> {
Receiver {
inner: self.inner,
phantom: PhantomData,
}
}
/// Polls for the next item.
pub fn poll_next_item(&mut self, cx: &mut Context) -> Poll<Result<Option<T>, Error>> {
match self.inner.poll_next_item(cx) {
Poll::Ready(Some(value)) => {
Poll::Ready(value.deserialize().map(Some).map_err(Error::invalid_item))
}
Poll::Ready(None) => Poll::Ready(Ok(None)),
Poll::Pending => Poll::Pending,
}
}
/// Returns the next item.
pub async fn next_item(&mut self) -> Result<Option<T>, Error> {
future::poll_fn(|cx| self.poll_next_item(cx)).await
}
}
impl<T: Deserialize> Stream for Receiver<T> {
type Item = Result<T, Error>;
fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Option<Self::Item>> {
self.poll_next_item(cx).map(Result::transpose)
}
}
impl<T: Deserialize> FusedStream for Receiver<T> {
fn is_terminated(&self) -> bool {
self.inner.is_terminated()
}
}
#[derive(Debug)]
pub(crate) struct ReceiverInner {
cookie: ChannelCookie,
state: Option<ReceiverInnerState>,
}
#[derive(Debug)]
struct ReceiverInnerState {
client: Handle,
items: mpsc::UnboundedReceiver<SerializedValue>,
max_capacity: NonZeroU32,
cur_capacity: u32,
}
impl ReceiverInner {
pub(crate) fn new(
cookie: ChannelCookie,
client: Handle,
items: mpsc::UnboundedReceiver<SerializedValue>,
max_capacity: NonZeroU32,
) -> Self {
Self {
cookie,
state: Some(ReceiverInnerState {
client,
items,
max_capacity,
cur_capacity: max_capacity.get(),
}),
}
}
async fn close(&mut self) -> Result<(), Error> {
if let Some(state) = self.state.take() {
state
.client
.close_channel_end(self.cookie, ChannelEnd::Receiver, true)?
.await
} else {
Ok(())
}
}
fn poll_next_item(&mut self, cx: &mut Context) -> Poll<Option<SerializedValue>> {
let Some(ref mut state) = self.state else {
return Poll::Ready(None);
};
debug_assert!(state.cur_capacity > 0);
debug_assert!(state.cur_capacity <= state.max_capacity.get());
let item = match Pin::new(&mut state.items).poll_next(cx) {
Poll::Ready(Some(item)) => item,
Poll::Ready(None) => {
self.state = None;
return Poll::Ready(None);
}
Poll::Pending => return Poll::Pending,
};
state.cur_capacity -= 1;
if state.cur_capacity <= LOW_CAPACITY {
let diff = state.max_capacity.get() - state.cur_capacity;
debug_assert!(diff >= 1);
state.client.add_channel_capacity(self.cookie, diff).ok();
state.cur_capacity += diff;
}
debug_assert!(state.cur_capacity > 0);
debug_assert!(state.cur_capacity <= state.max_capacity.get());
Poll::Ready(Some(item))
}
fn is_terminated(&self) -> bool {
if let Some(ref state) = self.state {
state.items.is_terminated()
} else {
true
}
}
}
impl Drop for ReceiverInner {
fn drop(&mut self) {
if let Some(state) = self.state.take() {
state
.client
.close_channel_end(self.cookie, ChannelEnd::Receiver, true)
.ok();
}
}
}