1 files changed, 250 insertions, 0 deletions
diff --git a/third_party/rust/warp/src/generic.rs b/third_party/rust/warp/src/generic.rs
new file mode 100644
index 0000000000..5350d22156
--- /dev/null
+++ b/third_party/rust/warp/src/generic.rs
@@ -0,0 +1,250 @@
+#[derive(Debug)]
+pub struct Product<H, T: HList>(pub(crate) H, pub(crate) T);
+
+pub type One<T> = (T,);
+
+#[inline]
+pub(crate) fn one<T>(val: T) -> One<T> {
+    (val,)
+}
+
+#[derive(Debug)]
+pub enum Either<T, U> {
+    A(T),
+    B(U),
+}
+
+// Converts Product (and ()) into tuples.
+pub trait HList: Sized {
+    type Tuple: Tuple<HList = Self>;
+
+    fn flatten(self) -> Self::Tuple;
+}
+
+// Typeclass that tuples can be converted into a Product (or unit ()).
+pub trait Tuple: Sized {
+    type HList: HList<Tuple = Self>;
+
+    fn hlist(self) -> Self::HList;
+
+    #[inline]
+    fn combine<T>(self, other: T) -> CombinedTuples<Self, T>
+    where
+        Self: Sized,
+        T: Tuple,
+        Self::HList: Combine<T::HList>,
+    {
+        self.hlist().combine(other.hlist()).flatten()
+    }
+}
+
+pub type CombinedTuples<T, U> =
+    <<<T as Tuple>::HList as Combine<<U as Tuple>::HList>>::Output as HList>::Tuple;
+
+// Combines Product together.
+pub trait Combine<T: HList> {
+    type Output: HList;
+
+    fn combine(self, other: T) -> Self::Output;
+}
+
+pub trait Func<Args> {
+    type Output;
+
+    fn call(&self, args: Args) -> Self::Output;
+}
+
+// ===== impl Combine =====
+
+impl<T: HList> Combine<T> for () {
+    type Output = T;
+    #[inline]
+    fn combine(self, other: T) -> Self::Output {
+        other
+    }
+}
+
+impl<H, T: HList, U: HList> Combine<U> for Product<H, T>
+where
+    T: Combine<U>,
+    Product<H, <T as Combine<U>>::Output>: HList,
+{
+    type Output = Product<H, <T as Combine<U>>::Output>;
+
+    #[inline]
+    fn combine(self, other: U) -> Self::Output {
+        Product(self.0, self.1.combine(other))
+    }
+}
+
+impl HList for () {
+    type Tuple = ();
+    #[inline]
+    fn flatten(self) -> Self::Tuple {}
+}
+
+impl Tuple for () {
+    type HList = ();
+
+    #[inline]
+    fn hlist(self) -> Self::HList {}
+}
+
+impl<F, R> Func<()> for F
+where
+    F: Fn() -> R,
+{
+    type Output = R;
+
+    #[inline]
+    fn call(&self, _args: ()) -> Self::Output {
+        (*self)()
+    }
+}
+
+impl<F, R> Func<crate::Rejection> for F
+where
+    F: Fn(crate::Rejection) -> R,
+{
+    type Output = R;
+
+    #[inline]
+    fn call(&self, arg: crate::Rejection) -> Self::Output {
+        (*self)(arg)
+    }
+}
+
+macro_rules! product {
+    ($H:expr) => { Product($H, ()) };
+    ($H:expr, $($T:expr),*) => { Product($H, product!($($T),*)) };
+}
+
+macro_rules! Product {
+    ($H:ty) => { Product<$H, ()> };
+    ($H:ty, $($T:ty),*) => { Product<$H, Product!($($T),*)> };
+}
+
+macro_rules! product_pat {
+    ($H:pat) => { Product($H, ()) };
+    ($H:pat, $($T:pat),*) => { Product($H, product_pat!($($T),*)) };
+}
+
+macro_rules! generics {
+    ($type:ident) => {
+        impl<$type> HList for Product!($type) {
+            type Tuple = ($type,);
+
+            #[inline]
+            fn flatten(self) -> Self::Tuple {
+                (self.0,)
+            }
+        }
+
+        impl<$type> Tuple for ($type,) {
+            type HList = Product!($type);
+            #[inline]
+            fn hlist(self) -> Self::HList {
+                product!(self.0)
+            }
+        }
+
+        impl<F, R, $type> Func<Product!($type)> for F
+        where
+            F: Fn($type) -> R,
+        {
+            type Output = R;
+
+            #[inline]
+            fn call(&self, args: Product!($type)) -> Self::Output {
+                (*self)(args.0)
+            }
+
+        }
+
+        impl<F, R, $type> Func<($type,)> for F
+        where
+            F: Fn($type) -> R,
+        {
+            type Output = R;
+
+            #[inline]
+            fn call(&self, args: ($type,)) -> Self::Output {
+                (*self)(args.0)
+            }
+        }
+
+    };
+
+    ($type1:ident, $( $type:ident ),*) => {
+        generics!($( $type ),*);
+
+        impl<$type1, $( $type ),*> HList for Product!($type1, $($type),*) {
+            type Tuple = ($type1, $( $type ),*);
+
+            #[inline]
+            fn flatten(self) -> Self::Tuple {
+                #[allow(non_snake_case)]
+                let product_pat!($type1, $( $type ),*) = self;
+                ($type1, $( $type ),*)
+            }
+        }
+
+        impl<$type1, $( $type ),*> Tuple for ($type1, $($type),*) {
+            type HList = Product!($type1, $( $type ),*);
+
+            #[inline]
+            fn hlist(self) -> Self::HList {
+                #[allow(non_snake_case)]
+                let ($type1, $( $type ),*) = self;
+                product!($type1, $( $type ),*)
+            }
+        }
+
+        impl<F, R, $type1, $( $type ),*> Func<Product!($type1, $($type),*)> for F
+        where
+            F: Fn($type1, $( $type ),*) -> R,
+        {
+            type Output = R;
+
+            #[inline]
+            fn call(&self, args: Product!($type1, $($type),*)) -> Self::Output {
+                #[allow(non_snake_case)]
+                let product_pat!($type1, $( $type ),*) = args;
+                (*self)($type1, $( $type ),*)
+            }
+        }
+
+        impl<F, R, $type1, $( $type ),*> Func<($type1, $($type),*)> for F
+        where
+            F: Fn($type1, $( $type ),*) -> R,
+        {
+            type Output = R;
+
+            #[inline]
+            fn call(&self, args: ($type1, $($type),*)) -> Self::Output {
+                #[allow(non_snake_case)]
+                let ($type1, $( $type ),*) = args;
+                (*self)($type1, $( $type ),*)
+            }
+        }
+    };
+}
+
+generics! {
+    T1,
+    T2,
+    T3,
+    T4,
+    T5,
+    T6,
+    T7,
+    T8,
+    T9,
+    T10,
+    T11,
+    T12,
+    T13,
+    T14,
+    T15,
+    T16
+}