axum/axum-core/src/macros.rs

macro_rules! define_rejection {
    (
        #[status = $status:ident]
        #[body = $body:expr]
        $(#[$m:meta])*
        pub struct $name:ident (Error);
    ) => {
        $(#[$m])*
        #[derive(Debug)]
        pub struct $name(pub(crate) crate::Error);

        impl $name {
            pub(crate) fn from_err<E>(err: E) -> Self
            where
                E: Into<crate::BoxError>,
            {
                Self(crate::Error::new(err))
            }
        }

        impl crate::response::IntoResponse for $name {
            fn into_response(self) -> $crate::response::Response {
                (
                    http::StatusCode::$status,
                    format!(concat!($body, ": {}"), self.0)
                ).into_response()
            }
        }

        impl std::fmt::Display for $name {
            fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
                write!(f, "{}", $body)
            }
        }

        impl std::error::Error for $name {
            fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
                Some(&self.0)
            }
        }
    };
}

macro_rules! composite_rejection {
    (
        $(#[$m:meta])*
        pub enum $name:ident {
            $($variant:ident),+
            $(,)?
        }
    ) => {
        $(#[$m])*
        #[derive(Debug)]
        #[non_exhaustive]
        pub enum $name {
            $(
                #[allow(missing_docs, deprecated)]
                $variant($variant)
            ),+
        }

        impl $crate::response::IntoResponse for $name {
            fn into_response(self) -> $crate::response::Response {
                match self {
                    $(
                        Self::$variant(inner) => inner.into_response(),
                    )+
                }
            }
        }

        $(
            #[allow(deprecated)]
            impl From<$variant> for $name {
                fn from(inner: $variant) -> Self {
                    Self::$variant(inner)
                }
            }
        )+

        impl std::fmt::Display for $name {
            fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
                match self {
                    $(
                        Self::$variant(inner) => write!(f, "{}", inner),
                    )+
                }
            }
        }

        impl std::error::Error for $name {
            fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
                match self {
                    $(
                        Self::$variant(inner) => Some(inner),
                    )+
                }
            }
        }
    };
}

macro_rules! all_the_tuples {
    ($name:ident) => {
        $name!(T1);
        $name!(T1, T2);
        $name!(T1, T2, T3);
        $name!(T1, T2, T3, T4);
        $name!(T1, T2, T3, T4, T5);
        $name!(T1, T2, T3, T4, T5, T6);
        $name!(T1, T2, T3, T4, T5, T6, T7);
        $name!(T1, T2, T3, T4, T5, T6, T7, T8);
        $name!(T1, T2, T3, T4, T5, T6, T7, T8, T9);
        $name!(T1, T2, T3, T4, T5, T6, T7, T8, T9, T10);
        $name!(T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11);
        $name!(T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12);
        $name!(T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13);
        $name!(T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14);
        $name!(T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15);
        $name!(T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16);
    };
}