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use async_std::{io, io::prelude::*};
use futures::Future;
pub async fn ask_user(message: impl std::fmt::Display, default_answer: bool) -> bool {
let message = format!(
"{} ({}/{}) ",
message,
if default_answer { "Y" } else { "y" },
if default_answer { "n" } else { "N" }
);
let mut stdout = io::stdout();
let stdin = io::stdin();
loop {
stdout.write(message.as_bytes()).await.unwrap();
stdout.flush().await.unwrap();
let mut answer = String::new();
stdin.read_line(&mut answer).await.unwrap();
match answer.to_lowercase().trim() {
"y" | "yes" => break true,
"n" | "no" => break false,
"" => break default_answer,
_ => {
stdout
.write("Please type y or n!\n".as_bytes())
.await
.unwrap();
stdout.flush().await.unwrap();
continue;
},
};
}
}
/// A weird mixture of [`futures::future::Abortable`], [`async_std::sync::Condvar`] and [`futures::future::Select`] tailored to our Ctrl+C handling.
///
/// At it's core, it is an `Abortable` but instead of having an `AbortHandle`, we use a future that resolves as trigger.
/// Under the hood, it is implementing the same functionality as a `select`, but mapping one of the outcomes to an error type.
pub async fn cancellable<T>(
future: impl Future<Output = T> + Unpin,
cancel: impl Future<Output = ()>,
) -> Result<T, Cancelled> {
use futures::future::Either;
futures::pin_mut!(cancel);
match futures::future::select(future, cancel).await {
Either::Left((val, _)) => Ok(val),
Either::Right(((), _)) => Err(Cancelled),
}
}
/// Indicator that the cancellable task was cancelled.
#[derive(Copy, Clone, Debug, Eq, PartialEq)]
pub struct Cancelled;
impl std::fmt::Display for Cancelled {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
write!(f, "Task has been cancelled")
}
}
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