// file: crates/ksp-job-api/src/cancellation.rs
// version: 1

/// Runtime-neutral cloneable token carrying cooperative cancellation intent.
#[derive(Clone)]
pub struct JobCancellationToken {
    requested: std::sync::Arc<std::sync::atomic::AtomicBool>,
}

impl JobCancellationToken {
    /// Creates a token with no cancellation request.
    #[must_use]
    pub fn new() -> Self {
        return Self { requested: std::sync::Arc::new(std::sync::atomic::AtomicBool::new(false)) };
    }

    /// Requests cancellation and returns `true` only for the first request shared by all clones.
    #[must_use]
    pub fn cancel(&self) -> bool {
        return !self.requested.swap(true, std::sync::atomic::Ordering::AcqRel);
    }

    /// Reports whether cancellation has been requested through any clone.
    #[must_use]
    pub fn is_cancellation_requested(&self) -> bool {
        return self.requested.load(std::sync::atomic::Ordering::Acquire);
    }
}

impl std::default::Default for JobCancellationToken {
    fn default() -> Self {
        return Self::new();
    }
}

impl std::fmt::Debug for JobCancellationToken {
    fn fmt(&self, formatter: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        return formatter.debug_struct("JobCancellationToken").field("cancellation_requested", &self.is_cancellation_requested()).finish();
    }
}

#[cfg(test)]
#[path = "../unit_tests/cancellation.rs"]
mod tests;