From 37a4b30d08f23126a0554aee9ff9713a9b06e1b6 Mon Sep 17 00:00:00 2001
From: David <dvdplm@gmail.com>
Date: Thu, 12 Jul 2018 17:43:18 +0200
Subject: [PATCH] environmental! handles generics (#307)
* Teach environmental! about generics
* whitespace
---
substrate/substrate/environmental/src/lib.rs | 43 ++++++++++++++++----
1 file changed, 35 insertions(+), 8 deletions(-)
diff --git a/substrate/substrate/environmental/src/lib.rs b/substrate/substrate/environmental/src/lib.rs
index 86e1100eccc..ff94c0c1ebb 100644
--- a/substrate/substrate/environmental/src/lib.rs
+++ b/substrate/substrate/environmental/src/lib.rs
@@ -190,33 +190,36 @@ macro_rules! environmental {
}
}
};
- ($name:ident : trait $t:ident) => {
- #[allow(non_camel_case_types)]
+ ($name:ident : trait @$t:ident [$($args:ty,)*]) => {
+ #[allow(non_camel_case_types, dead_code)]
struct $name { __private_field: () }
- thread_local_impl!(static GLOBAL: $crate::imp::RefCell<Option<*mut ($t + 'static)>>
+ thread_local_impl!(static GLOBAL: $crate::imp::RefCell<Option<*mut ($t<$($args),*> + 'static)>>
= $crate::imp::RefCell::new(None));
impl $name {
- #[allow(unused_imports)]
+ #[allow(unused_imports)]
pub fn using<R, F: FnOnce() -> R>(
- protected: &mut $t,
+ protected: &mut $t<$($args),*>,
f: F
) -> R {
let lifetime_extended = unsafe {
- $crate::imp::transmute::<&mut $t, &mut ($t + 'static)>(protected)
+ $crate::imp::transmute::<&mut $t<$($args),*>, &mut ($t<$($args),*> + 'static)>(protected)
};
$crate::using(&GLOBAL, lifetime_extended, f)
}
- pub fn with<R, F: for<'a> FnOnce(&'a mut ($t + 'a)) -> R>(
+ pub fn with<R, F: for<'a> FnOnce(&'a mut ($t<$($args),*> + 'a)) -> R>(
f: F
) -> Option<R> {
$crate::with(&GLOBAL, |x| f(x))
}
}
- }
+ };
+ ($name:ident : trait $t:ident <>) => { environmental! { $name : trait @$t [] } };
+ ($name:ident : trait $t:ident < $($args:ty),* $(,)* >) => { environmental! { $name : trait @$t [$($args,)*] } };
+ ($name:ident : trait $t:ident) => { environmental! { $name : trait @$t [] } };
}
#[cfg(test)]
@@ -322,4 +325,28 @@ mod tests {
assert_eq!(got_sum, 15);
}
+
+ #[test]
+ fn use_generic_trait() {
+ trait Plus { fn plus42() -> usize; }
+ struct ConcretePlus;
+ impl Plus for ConcretePlus {
+ fn plus42() -> usize { 42 }
+ }
+ trait Multiplier<T: Plus> { fn mul_and_add(&self) -> usize; }
+ impl<'a, P: Plus> Multiplier<P> for &'a [usize] {
+ fn mul_and_add(&self) -> usize {
+ self.iter().fold(1, |a, c| a * c) + P::plus42()
+ }
+ }
+
+ let numbers = vec![1, 2, 3];
+ let mut numbers = &numbers[..];
+ let out = foo::using(&mut numbers, || {
+ foo::with(|x| x.mul_and_add() )
+ }).unwrap();
+
+ assert_eq!(out, 6 + 42);
+ environmental!(foo: trait Multiplier<ConcretePlus>);
+ }
}
--
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