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-rw-r--r--third_party/rust/futures-util/src/fns.rs372
1 files changed, 372 insertions, 0 deletions
diff --git a/third_party/rust/futures-util/src/fns.rs b/third_party/rust/futures-util/src/fns.rs
new file mode 100644
index 0000000000..37ee03e6df
--- /dev/null
+++ b/third_party/rust/futures-util/src/fns.rs
@@ -0,0 +1,372 @@
+use core::fmt::{self, Debug};
+use core::marker::PhantomData;
+
+pub trait FnOnce1<A> {
+ type Output;
+ fn call_once(self, arg: A) -> Self::Output;
+}
+
+impl<T, A, R> FnOnce1<A> for T
+where
+ T: FnOnce(A) -> R,
+{
+ type Output = R;
+ fn call_once(self, arg: A) -> R {
+ self(arg)
+ }
+}
+
+pub trait FnMut1<A>: FnOnce1<A> {
+ fn call_mut(&mut self, arg: A) -> Self::Output;
+}
+
+impl<T, A, R> FnMut1<A> for T
+where
+ T: FnMut(A) -> R,
+{
+ fn call_mut(&mut self, arg: A) -> R {
+ self(arg)
+ }
+}
+
+// Not used, but present for completeness
+#[allow(unreachable_pub)]
+pub trait Fn1<A>: FnMut1<A> {
+ fn call(&self, arg: A) -> Self::Output;
+}
+
+impl<T, A, R> Fn1<A> for T
+where
+ T: Fn(A) -> R,
+{
+ fn call(&self, arg: A) -> R {
+ self(arg)
+ }
+}
+
+macro_rules! trivial_fn_impls {
+ ($name:ident <$($arg:ident),*> $t:ty = $debug:literal) => {
+ impl<$($arg),*> Copy for $t {}
+ impl<$($arg),*> Clone for $t {
+ fn clone(&self) -> Self { *self }
+ }
+ impl<$($arg),*> Debug for $t {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ f.write_str($debug)
+ }
+ }
+ impl<$($arg,)* A> FnMut1<A> for $t where Self: FnOnce1<A> {
+ fn call_mut(&mut self, arg: A) -> Self::Output {
+ self.call_once(arg)
+ }
+ }
+ impl<$($arg,)* A> Fn1<A> for $t where Self: FnOnce1<A> {
+ fn call(&self, arg: A) -> Self::Output {
+ self.call_once(arg)
+ }
+ }
+ pub(crate) fn $name<$($arg),*>() -> $t {
+ Default::default()
+ }
+ }
+}
+
+pub struct OkFn<E>(PhantomData<fn(E)>);
+
+impl<E> Default for OkFn<E> {
+ fn default() -> Self {
+ Self(PhantomData)
+ }
+}
+
+impl<A, E> FnOnce1<A> for OkFn<E> {
+ type Output = Result<A, E>;
+ fn call_once(self, arg: A) -> Self::Output {
+ Ok(arg)
+ }
+}
+
+trivial_fn_impls!(ok_fn <T> OkFn<T> = "Ok");
+
+#[derive(Debug, Copy, Clone, Default)]
+pub struct ChainFn<F, G>(F, G);
+
+impl<F, G, A> FnOnce1<A> for ChainFn<F, G>
+where
+ F: FnOnce1<A>,
+ G: FnOnce1<F::Output>,
+{
+ type Output = G::Output;
+ fn call_once(self, arg: A) -> Self::Output {
+ self.1.call_once(self.0.call_once(arg))
+ }
+}
+impl<F, G, A> FnMut1<A> for ChainFn<F, G>
+where
+ F: FnMut1<A>,
+ G: FnMut1<F::Output>,
+{
+ fn call_mut(&mut self, arg: A) -> Self::Output {
+ self.1.call_mut(self.0.call_mut(arg))
+ }
+}
+impl<F, G, A> Fn1<A> for ChainFn<F, G>
+where
+ F: Fn1<A>,
+ G: Fn1<F::Output>,
+{
+ fn call(&self, arg: A) -> Self::Output {
+ self.1.call(self.0.call(arg))
+ }
+}
+pub(crate) fn chain_fn<F, G>(f: F, g: G) -> ChainFn<F, G> {
+ ChainFn(f, g)
+}
+
+#[derive(Default)]
+pub struct MergeResultFn;
+
+impl<T> FnOnce1<Result<T, T>> for MergeResultFn {
+ type Output = T;
+ fn call_once(self, arg: Result<T, T>) -> Self::Output {
+ match arg {
+ Ok(x) => x,
+ Err(x) => x,
+ }
+ }
+}
+trivial_fn_impls!(merge_result_fn <> MergeResultFn = "merge_result");
+
+#[derive(Debug, Copy, Clone, Default)]
+pub struct InspectFn<F>(F);
+
+#[allow(single_use_lifetimes)] // https://github.com/rust-lang/rust/issues/55058
+impl<F, A> FnOnce1<A> for InspectFn<F>
+where
+ F: for<'a> FnOnce1<&'a A, Output = ()>,
+{
+ type Output = A;
+ fn call_once(self, arg: A) -> Self::Output {
+ self.0.call_once(&arg);
+ arg
+ }
+}
+#[allow(single_use_lifetimes)] // https://github.com/rust-lang/rust/issues/55058
+impl<F, A> FnMut1<A> for InspectFn<F>
+where
+ F: for<'a> FnMut1<&'a A, Output = ()>,
+{
+ fn call_mut(&mut self, arg: A) -> Self::Output {
+ self.0.call_mut(&arg);
+ arg
+ }
+}
+#[allow(single_use_lifetimes)] // https://github.com/rust-lang/rust/issues/55058
+impl<F, A> Fn1<A> for InspectFn<F>
+where
+ F: for<'a> Fn1<&'a A, Output = ()>,
+{
+ fn call(&self, arg: A) -> Self::Output {
+ self.0.call(&arg);
+ arg
+ }
+}
+pub(crate) fn inspect_fn<F>(f: F) -> InspectFn<F> {
+ InspectFn(f)
+}
+
+#[derive(Debug, Copy, Clone, Default)]
+pub struct MapOkFn<F>(F);
+
+impl<F, T, E> FnOnce1<Result<T, E>> for MapOkFn<F>
+where
+ F: FnOnce1<T>,
+{
+ type Output = Result<F::Output, E>;
+ fn call_once(self, arg: Result<T, E>) -> Self::Output {
+ arg.map(|x| self.0.call_once(x))
+ }
+}
+impl<F, T, E> FnMut1<Result<T, E>> for MapOkFn<F>
+where
+ F: FnMut1<T>,
+{
+ fn call_mut(&mut self, arg: Result<T, E>) -> Self::Output {
+ arg.map(|x| self.0.call_mut(x))
+ }
+}
+impl<F, T, E> Fn1<Result<T, E>> for MapOkFn<F>
+where
+ F: Fn1<T>,
+{
+ fn call(&self, arg: Result<T, E>) -> Self::Output {
+ arg.map(|x| self.0.call(x))
+ }
+}
+pub(crate) fn map_ok_fn<F>(f: F) -> MapOkFn<F> {
+ MapOkFn(f)
+}
+
+#[derive(Debug, Copy, Clone, Default)]
+pub struct MapErrFn<F>(F);
+
+impl<F, T, E> FnOnce1<Result<T, E>> for MapErrFn<F>
+where
+ F: FnOnce1<E>,
+{
+ type Output = Result<T, F::Output>;
+ fn call_once(self, arg: Result<T, E>) -> Self::Output {
+ arg.map_err(|x| self.0.call_once(x))
+ }
+}
+impl<F, T, E> FnMut1<Result<T, E>> for MapErrFn<F>
+where
+ F: FnMut1<E>,
+{
+ fn call_mut(&mut self, arg: Result<T, E>) -> Self::Output {
+ arg.map_err(|x| self.0.call_mut(x))
+ }
+}
+impl<F, T, E> Fn1<Result<T, E>> for MapErrFn<F>
+where
+ F: Fn1<E>,
+{
+ fn call(&self, arg: Result<T, E>) -> Self::Output {
+ arg.map_err(|x| self.0.call(x))
+ }
+}
+pub(crate) fn map_err_fn<F>(f: F) -> MapErrFn<F> {
+ MapErrFn(f)
+}
+
+#[derive(Debug, Copy, Clone)]
+pub struct InspectOkFn<F>(F);
+
+impl<'a, F, T, E> FnOnce1<&'a Result<T, E>> for InspectOkFn<F>
+where
+ F: FnOnce1<&'a T, Output = ()>,
+{
+ type Output = ();
+ fn call_once(self, arg: &'a Result<T, E>) -> Self::Output {
+ if let Ok(x) = arg {
+ self.0.call_once(x)
+ }
+ }
+}
+impl<'a, F, T, E> FnMut1<&'a Result<T, E>> for InspectOkFn<F>
+where
+ F: FnMut1<&'a T, Output = ()>,
+{
+ fn call_mut(&mut self, arg: &'a Result<T, E>) -> Self::Output {
+ if let Ok(x) = arg {
+ self.0.call_mut(x)
+ }
+ }
+}
+impl<'a, F, T, E> Fn1<&'a Result<T, E>> for InspectOkFn<F>
+where
+ F: Fn1<&'a T, Output = ()>,
+{
+ fn call(&self, arg: &'a Result<T, E>) -> Self::Output {
+ if let Ok(x) = arg {
+ self.0.call(x)
+ }
+ }
+}
+pub(crate) fn inspect_ok_fn<F>(f: F) -> InspectOkFn<F> {
+ InspectOkFn(f)
+}
+
+#[derive(Debug, Copy, Clone)]
+pub struct InspectErrFn<F>(F);
+
+impl<'a, F, T, E> FnOnce1<&'a Result<T, E>> for InspectErrFn<F>
+where
+ F: FnOnce1<&'a E, Output = ()>,
+{
+ type Output = ();
+ fn call_once(self, arg: &'a Result<T, E>) -> Self::Output {
+ if let Err(x) = arg {
+ self.0.call_once(x)
+ }
+ }
+}
+impl<'a, F, T, E> FnMut1<&'a Result<T, E>> for InspectErrFn<F>
+where
+ F: FnMut1<&'a E, Output = ()>,
+{
+ fn call_mut(&mut self, arg: &'a Result<T, E>) -> Self::Output {
+ if let Err(x) = arg {
+ self.0.call_mut(x)
+ }
+ }
+}
+impl<'a, F, T, E> Fn1<&'a Result<T, E>> for InspectErrFn<F>
+where
+ F: Fn1<&'a E, Output = ()>,
+{
+ fn call(&self, arg: &'a Result<T, E>) -> Self::Output {
+ if let Err(x) = arg {
+ self.0.call(x)
+ }
+ }
+}
+pub(crate) fn inspect_err_fn<F>(f: F) -> InspectErrFn<F> {
+ InspectErrFn(f)
+}
+
+pub(crate) type MapOkOrElseFn<F, G> = ChainFn<MapOkFn<F>, ChainFn<MapErrFn<G>, MergeResultFn>>;
+pub(crate) fn map_ok_or_else_fn<F, G>(f: F, g: G) -> MapOkOrElseFn<F, G> {
+ chain_fn(map_ok_fn(f), chain_fn(map_err_fn(g), merge_result_fn()))
+}
+
+#[derive(Debug, Copy, Clone, Default)]
+pub struct UnwrapOrElseFn<F>(F);
+
+impl<F, T, E> FnOnce1<Result<T, E>> for UnwrapOrElseFn<F>
+where
+ F: FnOnce1<E, Output = T>,
+{
+ type Output = T;
+ fn call_once(self, arg: Result<T, E>) -> Self::Output {
+ arg.unwrap_or_else(|x| self.0.call_once(x))
+ }
+}
+impl<F, T, E> FnMut1<Result<T, E>> for UnwrapOrElseFn<F>
+where
+ F: FnMut1<E, Output = T>,
+{
+ fn call_mut(&mut self, arg: Result<T, E>) -> Self::Output {
+ arg.unwrap_or_else(|x| self.0.call_mut(x))
+ }
+}
+impl<F, T, E> Fn1<Result<T, E>> for UnwrapOrElseFn<F>
+where
+ F: Fn1<E, Output = T>,
+{
+ fn call(&self, arg: Result<T, E>) -> Self::Output {
+ arg.unwrap_or_else(|x| self.0.call(x))
+ }
+}
+pub(crate) fn unwrap_or_else_fn<F>(f: F) -> UnwrapOrElseFn<F> {
+ UnwrapOrElseFn(f)
+}
+
+pub struct IntoFn<T>(PhantomData<fn() -> T>);
+
+impl<T> Default for IntoFn<T> {
+ fn default() -> Self {
+ Self(PhantomData)
+ }
+}
+impl<A, T> FnOnce1<A> for IntoFn<T>
+where
+ A: Into<T>,
+{
+ type Output = T;
+ fn call_once(self, arg: A) -> Self::Output {
+ arg.into()
+ }
+}
+
+trivial_fn_impls!(into_fn <T> IntoFn<T> = "Into::into");
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