File size: 2,053 Bytes
1e92f2d | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 | use std::{
any::{Any, TypeId},
hash::{Hash, Hasher},
};
/// A dynamic-dispatch version of the [`PartialEq`] trait. Implemented for every type that
/// implements [`Any`] + [`PartialEq`].
pub trait DynPartialEq: Any {
fn dyn_partial_eq(&self, other: &dyn Any) -> bool;
}
impl<T: Any + PartialEq> DynPartialEq for T {
fn dyn_partial_eq(&self, other: &dyn Any) -> bool {
other
.downcast_ref::<Self>()
.map(|other| PartialEq::eq(self, other))
.unwrap_or(false)
}
}
#[macro_export]
macro_rules! impl_partial_eq_for_dyn {
($ty:ty) => {
impl ::std::cmp::PartialEq for $ty {
fn eq(&self, other: &Self) -> bool {
$crate::DynPartialEq::dyn_partial_eq(self, other as &dyn ::std::any::Any)
}
}
};
}
/// A dynamic-dispatch version of the [`Eq`] trait. Implemented for every type that implements
/// [`Any`] + [`Eq`].
pub trait DynEq: DynPartialEq {}
impl<T: Any + Eq> DynEq for T {}
#[macro_export]
macro_rules! impl_eq_for_dyn {
($ty:ty) => {
impl ::std::cmp::Eq for $ty {}
};
}
/// A dynamic-dispatch version of the [`Hash`] trait. Implemented for every type that implements
/// [`Any`] + [`Hash`].
///
/// The `TypeId::of::<Self>()` value is included in the resulting hash, so the hash generated by
/// `DynEqHash` will not match the hash generated by the underlying `Hash` implementation. In other
/// words, the hash of `T` will not match the hash of `T as dyn SomeDynHashTrait`.
pub trait DynHash {
fn dyn_hash(&self, state: &mut dyn Hasher);
}
impl<T: Any + Hash> DynHash for T {
fn dyn_hash(&self, mut state: &mut dyn Hasher) {
Hash::hash(&(TypeId::of::<Self>(), self), &mut state);
}
}
#[macro_export]
macro_rules! impl_hash_for_dyn {
($ty:ty) => {
impl ::std::hash::Hash for $ty {
fn hash<H: ::std::hash::Hasher>(&self, state: &mut H) {
$crate::DynHash::dyn_hash(self, state as &mut dyn (::std::hash::Hasher))
}
}
};
}
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