axum/src/macros.rs

//! Internal macros

macro_rules! opaque_future {
    ($(#[$m:meta])* pub type $name:ident = $actual:ty;) => {
        opaque_future! {
            $(#[$m])*
            pub type $name<> = $actual;
        }
    };

    ($(#[$m:meta])* pub type $name:ident<$($param:ident),*> = $actual:ty;) => {
        #[pin_project::pin_project]
        $(#[$m])*
        pub struct $name<$($param),*>(#[pin] pub(crate) $actual)
        where;

        impl<$($param),*> std::fmt::Debug for $name<$($param),*> {
            fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
                f.debug_tuple(stringify!($name)).field(&format_args!("...")).finish()
            }
        }

        impl<$($param),*> std::future::Future for $name<$($param),*>
        where
            $actual: std::future::Future,
        {
            type Output = <$actual as std::future::Future>::Output;
            #[inline]
            fn poll(self: std::pin::Pin<&mut Self>, cx: &mut std::task::Context<'_>) -> std::task::Poll<Self::Output> {
                self.project().0.poll(cx)
            }
        }
    };
}