monotonic-clock.wit

package wasi:[email protected];
/// WASI Monotonic Clock is a clock API intended to let users measure elapsed
/// time.
///
/// It is intended to be portable at least between Unix-family platforms and
/// Windows.
///
/// A monotonic clock is a clock which has an unspecified initial value, and
/// successive reads of the clock will produce non-decreasing values.
@since(version = 0.2.0)
interface monotonic-clock {
    @since(version = 0.2.0)
    use wasi:io/[email protected].{pollable};

    /// An instant in time, in nanoseconds. An instant is relative to an
    /// unspecified initial value, and can only be compared to instances from
    /// the same monotonic-clock.
    @since(version = 0.2.0)
    type instant = u64;

    /// A duration of time, in nanoseconds.
    @since(version = 0.2.0)
    type duration = u64;

    /// Read the current value of the clock.
    ///
    /// The clock is monotonic, therefore calling this function repeatedly will
    /// produce a sequence of non-decreasing values.
    @since(version = 0.2.0)
    now: func() -> instant;

    /// Query the resolution of the clock. Returns the duration of time
    /// corresponding to a clock tick.
    @since(version = 0.2.0)
    resolution: func() -> duration;

    /// Create a `pollable` which will resolve once the specified instant
    /// has occurred.
    @since(version = 0.2.0)
    subscribe-instant: func(
        when: instant,
    ) -> pollable;

    /// Create a `pollable` that will resolve after the specified duration has
    /// elapsed from the time this function is invoked.
    @since(version = 0.2.0)
    subscribe-duration: func(
        when: duration,
    ) -> pollable;
}