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use super::*;
/// New paired [`ResponderVar`] and [`ResponseVar`] in the waiting state.
pub fn response_var<T: VarValue>() -> (ResponderVar<T>, ResponseVar<T>) {
let responder = var(Response::Waiting::<T>);
let response = responder.read_only();
(responder, response)
}
/// New [`ResponseVar`] in the done state.
pub fn response_done_var<T: VarValue>(response: T) -> ResponseVar<T> {
var(Response::Done(response)).read_only()
}
/// Variable used to notify the completion of an async operation.
///
/// Use [`response_var`] to init.
pub type ResponderVar<T> = ArcVar<Response<T>>;
/// Variable used to listen to a one time signal that an async operation has completed.
///
/// Use [`response_var`] or [`response_done_var`] to init.
pub type ResponseVar<T> = types::ReadOnlyVar<Response<T>, ArcVar<Response<T>>>;
/// Raw value in a [`ResponseVar`].
#[derive(Clone, Copy, PartialEq)]
pub enum Response<T: VarValue> {
/// Responder has not set the response yet.
Waiting,
/// Responder has set the response.
Done(T),
}
impl<T: VarValue> Response<T> {
/// Has response.
pub fn is_done(&self) -> bool {
matches!(self, Response::Done(_))
}
/// Does not have response.
pub fn is_waiting(&self) -> bool {
matches!(self, Response::Waiting)
}
/// Gets the response if done.
pub fn done(&self) -> Option<&T> {
match self {
Response::Waiting => None,
Response::Done(r) => Some(r),
}
}
}
impl<T: VarValue> fmt::Debug for Response<T> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
if f.alternate() {
match self {
Response::Waiting => {
write!(f, "Response::Waiting")
}
Response::Done(v) => f.debug_tuple("Response::Done").field(v).finish(),
}
} else {
match self {
Response::Waiting => {
write!(f, "Waiting")
}
Response::Done(v) => fmt::Debug::fmt(v, f),
}
}
}
}
impl<T: VarValue> From<Response<T>> for Option<T> {
fn from(value: Response<T>) -> Self {
match value {
Response::Waiting => None,
Response::Done(r) => Some(r),
}
}
}
impl<T: VarValue> ResponseVar<T> {
/// Visit the response, if present.
pub fn with_rsp<R>(&self, read: impl FnOnce(&T) -> R) -> Option<R> {
self.with(|value| match value {
Response::Waiting => None,
Response::Done(value) => Some(read(value)),
})
}
/// Visit the response, if present and new.
pub fn with_new_rsp<R>(&self, read: impl FnOnce(&T) -> R) -> Option<R> {
self.with_new(|value| match value {
Response::Waiting => None,
Response::Done(value) => Some(read(value)),
})
.flatten()
}
/// If the response is received.
pub fn is_done(&self) -> bool {
self.with(Response::is_done)
}
/// If the response is not received yet.
pub fn is_waiting(&self) -> bool {
self.with(Response::is_waiting)
}
/// Clone the response value, if present.
pub fn rsp(&self) -> Option<T> {
self.with_rsp(Clone::clone)
}
/// Returns a future that awaits until a response is received and then returns a clone.
pub async fn wait_rsp(&self) -> T {
self.wait_done().await;
self.rsp().unwrap()
}
/// Returns a future that awaits until a response is received and then returns it.
///
/// Will clone the value if the variable is shared.
pub async fn wait_into_rsp(self) -> T {
self.wait_done().await;
self.into_rsp().unwrap()
}
/// Returns a future that awaits until a response is received.
///
/// [`rsp`]: Self::rsp
pub async fn wait_done(&self) {
self.wait_value(Response::is_done).await;
}
/// Clone the response, if present and new.
pub fn rsp_new(&self) -> Option<T> {
self.with_new_rsp(Clone::clone)
}
/// Into response, if received.
///
/// Clones if the variable is has more than one strong reference.
pub fn into_rsp(self) -> Option<T> {
self.into_value().into()
}
/// Map the response value using `map`, if the variable is awaiting a response uses the `waiting_value` first.
pub fn map_rsp<O, I, M>(&self, waiting_value: I, map: M) -> impl Var<O>
where
O: VarValue,
I: Fn() -> O + Send + Sync + 'static,
M: FnOnce(&T) -> O + Send + 'static,
{
let mut map = Some(map);
self.filter_map(
move |r| match r {
Response::Waiting => None,
Response::Done(r) => map.take().map(|m| m(r)),
},
waiting_value,
)
}
}
impl<T: VarValue> ResponderVar<T> {
/// Sets the one time response.
pub fn respond(&self, response: T) {
self.set(Response::Done(response));
}
/// Creates a [`ResponseVar`] linked to this responder.
pub fn response_var(&self) -> ResponseVar<T> {
self.read_only()
}
}