// option. This file may not be copied, modified, or distributed
// except according to those terms.
-use std::hash::Hasher;
+use std::hash::{Hash, Hasher};
use std::marker::PhantomData;
use std::mem;
use blake2b::Blake2bHasher;
/// This hasher currently always uses the stable Blake2b algorithm
/// and allows for variable output lengths through its type
/// parameter.
-#[derive(Debug)]
pub struct StableHasher<W> {
state: Blake2bHasher,
bytes_hashed: u64,
width: PhantomData<W>,
}
+impl<W: StableHasherResult> ::std::fmt::Debug for StableHasher<W> {
+ fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+ write!(f, "{:?}", self.state)
+ }
+}
+
pub trait StableHasherResult: Sized {
fn finish(hasher: StableHasher<Self>) -> Self;
}
self.write_ileb128(i as i64);
}
}
+
+
+/// Something that implements `HashStable<CTX>` can be hashed in a way that is
+/// stable across multiple compiliation sessions.
+pub trait HashStable<CTX> {
+ fn hash_stable<W: StableHasherResult>(&self,
+ hcx: &mut CTX,
+ hasher: &mut StableHasher<W>);
+}
+
+// Implement HashStable by just calling `Hash::hash()`. This works fine for
+// self-contained values that don't depend on the hashing context `CTX`.
+macro_rules! impl_stable_hash_via_hash {
+ ($t:ty) => (
+ impl<CTX> HashStable<CTX> for $t {
+ #[inline]
+ fn hash_stable<W: StableHasherResult>(&self,
+ _: &mut CTX,
+ hasher: &mut StableHasher<W>) {
+ ::std::hash::Hash::hash(self, hasher);
+ }
+ }
+ );
+}
+
+impl_stable_hash_via_hash!(i8);
+impl_stable_hash_via_hash!(i16);
+impl_stable_hash_via_hash!(i32);
+impl_stable_hash_via_hash!(i64);
+impl_stable_hash_via_hash!(isize);
+
+impl_stable_hash_via_hash!(u8);
+impl_stable_hash_via_hash!(u16);
+impl_stable_hash_via_hash!(u32);
+impl_stable_hash_via_hash!(u64);
+impl_stable_hash_via_hash!(usize);
+
+impl_stable_hash_via_hash!(u128);
+impl_stable_hash_via_hash!(i128);
+
+impl_stable_hash_via_hash!(char);
+impl_stable_hash_via_hash!(());
+
+impl<CTX> HashStable<CTX> for f32 {
+ fn hash_stable<W: StableHasherResult>(&self,
+ ctx: &mut CTX,
+ hasher: &mut StableHasher<W>) {
+ let val: u32 = unsafe {
+ ::std::mem::transmute(*self)
+ };
+ val.hash_stable(ctx, hasher);
+ }
+}
+
+impl<CTX> HashStable<CTX> for f64 {
+ fn hash_stable<W: StableHasherResult>(&self,
+ ctx: &mut CTX,
+ hasher: &mut StableHasher<W>) {
+ let val: u64 = unsafe {
+ ::std::mem::transmute(*self)
+ };
+ val.hash_stable(ctx, hasher);
+ }
+}
+
+impl<T1: HashStable<CTX>, T2: HashStable<CTX>, CTX> HashStable<CTX> for (T1, T2) {
+ fn hash_stable<W: StableHasherResult>(&self,
+ ctx: &mut CTX,
+ hasher: &mut StableHasher<W>) {
+ self.0.hash_stable(ctx, hasher);
+ self.1.hash_stable(ctx, hasher);
+ }
+}
+
+impl<T: HashStable<CTX>, CTX> HashStable<CTX> for [T] {
+ default fn hash_stable<W: StableHasherResult>(&self,
+ ctx: &mut CTX,
+ hasher: &mut StableHasher<W>) {
+ self.len().hash_stable(ctx, hasher);
+ for item in self {
+ item.hash_stable(ctx, hasher);
+ }
+ }
+}
+
+impl<T: HashStable<CTX>, CTX> HashStable<CTX> for Vec<T> {
+ #[inline]
+ fn hash_stable<W: StableHasherResult>(&self,
+ ctx: &mut CTX,
+ hasher: &mut StableHasher<W>) {
+ (&self[..]).hash_stable(ctx, hasher);
+ }
+}
+
+impl<CTX> HashStable<CTX> for str {
+ #[inline]
+ fn hash_stable<W: StableHasherResult>(&self,
+ _: &mut CTX,
+ hasher: &mut StableHasher<W>) {
+ self.len().hash(hasher);
+ self.as_bytes().hash(hasher);
+ }
+}
+
+impl<CTX> HashStable<CTX> for bool {
+ #[inline]
+ fn hash_stable<W: StableHasherResult>(&self,
+ ctx: &mut CTX,
+ hasher: &mut StableHasher<W>) {
+ (if *self { 1u8 } else { 0u8 }).hash_stable(ctx, hasher);
+ }
+}
+
+
+impl<T, CTX> HashStable<CTX> for Option<T>
+ where T: HashStable<CTX>
+{
+ #[inline]
+ fn hash_stable<W: StableHasherResult>(&self,
+ ctx: &mut CTX,
+ hasher: &mut StableHasher<W>) {
+ if let Some(ref value) = *self {
+ 1u8.hash_stable(ctx, hasher);
+ value.hash_stable(ctx, hasher);
+ } else {
+ 0u8.hash_stable(ctx, hasher);
+ }
+ }
+}
+
+impl<'a, T, CTX> HashStable<CTX> for &'a T
+ where T: HashStable<CTX>
+{
+ #[inline]
+ fn hash_stable<W: StableHasherResult>(&self,
+ ctx: &mut CTX,
+ hasher: &mut StableHasher<W>) {
+ (**self).hash_stable(ctx, hasher);
+ }
+}
+
+impl<T, CTX> HashStable<CTX> for ::std::mem::Discriminant<T> {
+ #[inline]
+ fn hash_stable<W: StableHasherResult>(&self,
+ _: &mut CTX,
+ hasher: &mut StableHasher<W>) {
+ ::std::hash::Hash::hash(self, hasher);
+ }
+}
+
+impl<K, V, CTX> HashStable<CTX> for ::std::collections::BTreeMap<K, V>
+ where K: Ord + HashStable<CTX>,
+ V: HashStable<CTX>,
+{
+ fn hash_stable<W: StableHasherResult>(&self,
+ ctx: &mut CTX,
+ hasher: &mut StableHasher<W>) {
+ self.len().hash_stable(ctx, hasher);
+ for (k, v) in self {
+ k.hash_stable(ctx, hasher);
+ v.hash_stable(ctx, hasher);
+ }
+ }
+}
+
+impl<T, CTX> HashStable<CTX> for ::std::collections::BTreeSet<T>
+ where T: Ord + HashStable<CTX>,
+{
+ fn hash_stable<W: StableHasherResult>(&self,
+ ctx: &mut CTX,
+ hasher: &mut StableHasher<W>) {
+ self.len().hash_stable(ctx, hasher);
+ for v in self {
+ v.hash_stable(ctx, hasher);
+ }
+ }
+}
+
+impl<I: ::indexed_vec::Idx, T, CTX> HashStable<CTX> for ::indexed_vec::IndexVec<I, T>
+ where T: HashStable<CTX>,
+{
+ fn hash_stable<W: StableHasherResult>(&self,
+ ctx: &mut CTX,
+ hasher: &mut StableHasher<W>) {
+ self.len().hash_stable(ctx, hasher);
+ for v in &self.raw {
+ v.hash_stable(ctx, hasher);
+ }
+ }
+}
projects / rust.git / blobdiff