autocommit 2022-02-24 16:30:11 CET

src/utils/tri.rs

@@ -0,0 +1,49 @@
+use std::future::Future;
+use std::marker::PhantomData;
+use std::pin::Pin;
+use std::task::{Context, Poll};
+
+pub trait Try: Sized {
+    fn tri<F>(f: F) -> Result<(), Self>
+    where
+        F: FnOnce() -> Result<(), Self>;
+
+    fn tria<F>(f: F) -> Tria<Self, F>
+    where
+        F: Future<Output = Result<(), Self>>;
+}
+
+impl<E> Try for E {
+    fn tri<F>(f: F) -> Result<(), Self>
+    where
+        F: FnOnce() -> Result<(), Self>,
+    {
+        f()
+    }
+
+    fn tria<F>(f: F) -> Tria<E, F>
+    where
+        F: Future<Output = Result<(), Self>>,
+    {
+        Tria {
+            f,
+            _phantom: Default::default(),
+        }
+    }
+}
+
+pub struct Tria<E, F> {
+    f: F,
+    _phantom: PhantomData<E>,
+}
+
+impl<E, F> Future for Tria<E, F>
+where
+    F: Future<Output = Result<(), E>>,
+{
+    type Output = Result<(), E>;
+
+    fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
+        unsafe { Pin::new_unchecked(&mut Pin::get_unchecked_mut(self).f).poll(cx) }
+    }
+}