574 lines
17 KiB
Rust
574 lines
17 KiB
Rust
use std::hash::{Hash, Hasher, BuildHasher};
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use std::marker::PhantomData;
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use std::mem;
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use crate::sip128::SipHasher128;
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use crate::indexed_vec;
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use crate::bit_set;
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/// When hashing something that ends up affecting properties like symbol names,
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/// we want these symbol names to be calculated independently of other factors
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/// like what architecture you're compiling *from*.
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///
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/// To that end we always convert integers to little-endian format before
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/// hashing and the architecture dependent `isize` and `usize` types are
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/// extended to 64 bits if needed.
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pub struct StableHasher<W> {
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state: SipHasher128,
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bytes_hashed: u64,
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width: PhantomData<W>,
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}
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impl<W: StableHasherResult> ::std::fmt::Debug for StableHasher<W> {
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fn fmt(&self, f: &mut ::std::fmt::Formatter<'_>) -> ::std::fmt::Result {
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write!(f, "{:?}", self.state)
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}
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}
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pub trait StableHasherResult: Sized {
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fn finish(hasher: StableHasher<Self>) -> Self;
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}
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impl<W: StableHasherResult> StableHasher<W> {
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pub fn new() -> Self {
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StableHasher {
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state: SipHasher128::new_with_keys(0, 0),
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bytes_hashed: 0,
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width: PhantomData,
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}
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}
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pub fn finish(self) -> W {
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W::finish(self)
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}
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}
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impl StableHasherResult for u128 {
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fn finish(hasher: StableHasher<Self>) -> Self {
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let (_0, _1) = hasher.finalize();
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(_0 as u128) | ((_1 as u128) << 64)
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}
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}
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impl StableHasherResult for u64 {
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fn finish(hasher: StableHasher<Self>) -> Self {
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hasher.finalize().0
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}
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}
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impl<W> StableHasher<W> {
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#[inline]
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pub fn finalize(self) -> (u64, u64) {
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self.state.finish128()
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}
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#[inline]
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pub fn bytes_hashed(&self) -> u64 {
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self.bytes_hashed
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}
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}
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impl<W> Hasher for StableHasher<W> {
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fn finish(&self) -> u64 {
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panic!("use StableHasher::finalize instead");
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}
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#[inline]
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fn write(&mut self, bytes: &[u8]) {
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self.state.write(bytes);
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self.bytes_hashed += bytes.len() as u64;
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}
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#[inline]
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fn write_u8(&mut self, i: u8) {
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self.state.write_u8(i);
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self.bytes_hashed += 1;
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}
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#[inline]
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fn write_u16(&mut self, i: u16) {
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self.state.write_u16(i.to_le());
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self.bytes_hashed += 2;
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}
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#[inline]
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fn write_u32(&mut self, i: u32) {
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self.state.write_u32(i.to_le());
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self.bytes_hashed += 4;
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}
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#[inline]
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fn write_u64(&mut self, i: u64) {
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self.state.write_u64(i.to_le());
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self.bytes_hashed += 8;
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}
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#[inline]
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fn write_u128(&mut self, i: u128) {
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self.state.write_u128(i.to_le());
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self.bytes_hashed += 16;
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}
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#[inline]
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fn write_usize(&mut self, i: usize) {
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// Always treat usize as u64 so we get the same results on 32 and 64 bit
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// platforms. This is important for symbol hashes when cross compiling,
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// for example.
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self.state.write_u64((i as u64).to_le());
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self.bytes_hashed += 8;
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}
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#[inline]
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fn write_i8(&mut self, i: i8) {
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self.state.write_i8(i);
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self.bytes_hashed += 1;
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}
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#[inline]
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fn write_i16(&mut self, i: i16) {
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self.state.write_i16(i.to_le());
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self.bytes_hashed += 2;
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}
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#[inline]
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fn write_i32(&mut self, i: i32) {
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self.state.write_i32(i.to_le());
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self.bytes_hashed += 4;
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}
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#[inline]
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fn write_i64(&mut self, i: i64) {
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self.state.write_i64(i.to_le());
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self.bytes_hashed += 8;
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}
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#[inline]
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fn write_i128(&mut self, i: i128) {
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self.state.write_i128(i.to_le());
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self.bytes_hashed += 16;
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}
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#[inline]
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fn write_isize(&mut self, i: isize) {
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// Always treat isize as i64 so we get the same results on 32 and 64 bit
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// platforms. This is important for symbol hashes when cross compiling,
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// for example.
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self.state.write_i64((i as i64).to_le());
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self.bytes_hashed += 8;
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}
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}
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/// Something that implements `HashStable<CTX>` can be hashed in a way that is
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/// stable across multiple compilation sessions.
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pub trait HashStable<CTX> {
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fn hash_stable<W: StableHasherResult>(&self,
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hcx: &mut CTX,
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hasher: &mut StableHasher<W>);
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}
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/// Implement this for types that can be turned into stable keys like, for
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/// example, for DefId that can be converted to a DefPathHash. This is used for
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/// bringing maps into a predictable order before hashing them.
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pub trait ToStableHashKey<HCX> {
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type KeyType: Ord + Clone + Sized + HashStable<HCX>;
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fn to_stable_hash_key(&self, hcx: &HCX) -> Self::KeyType;
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}
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// Implement HashStable by just calling `Hash::hash()`. This works fine for
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// self-contained values that don't depend on the hashing context `CTX`.
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#[macro_export]
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macro_rules! impl_stable_hash_via_hash {
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($t:ty) => (
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impl<CTX> $crate::stable_hasher::HashStable<CTX> for $t {
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#[inline]
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fn hash_stable<W: $crate::stable_hasher::StableHasherResult>(
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&self,
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_: &mut CTX,
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hasher: &mut $crate::stable_hasher::StableHasher<W>
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) {
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::std::hash::Hash::hash(self, hasher);
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}
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}
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);
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}
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impl_stable_hash_via_hash!(i8);
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impl_stable_hash_via_hash!(i16);
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impl_stable_hash_via_hash!(i32);
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impl_stable_hash_via_hash!(i64);
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impl_stable_hash_via_hash!(isize);
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impl_stable_hash_via_hash!(u8);
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impl_stable_hash_via_hash!(u16);
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impl_stable_hash_via_hash!(u32);
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impl_stable_hash_via_hash!(u64);
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impl_stable_hash_via_hash!(usize);
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impl_stable_hash_via_hash!(u128);
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impl_stable_hash_via_hash!(i128);
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impl_stable_hash_via_hash!(char);
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impl_stable_hash_via_hash!(());
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impl<CTX> HashStable<CTX> for ::std::num::NonZeroU32 {
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fn hash_stable<W: StableHasherResult>(&self,
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ctx: &mut CTX,
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hasher: &mut StableHasher<W>) {
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self.get().hash_stable(ctx, hasher)
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}
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}
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impl<CTX> HashStable<CTX> for f32 {
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fn hash_stable<W: StableHasherResult>(&self,
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ctx: &mut CTX,
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hasher: &mut StableHasher<W>) {
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let val: u32 = unsafe {
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::std::mem::transmute(*self)
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};
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val.hash_stable(ctx, hasher);
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}
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}
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impl<CTX> HashStable<CTX> for f64 {
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fn hash_stable<W: StableHasherResult>(&self,
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ctx: &mut CTX,
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hasher: &mut StableHasher<W>) {
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let val: u64 = unsafe {
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::std::mem::transmute(*self)
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};
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val.hash_stable(ctx, hasher);
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}
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}
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impl<CTX> HashStable<CTX> for ::std::cmp::Ordering {
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fn hash_stable<W: StableHasherResult>(&self,
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ctx: &mut CTX,
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hasher: &mut StableHasher<W>) {
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(*self as i8).hash_stable(ctx, hasher);
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}
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}
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impl<T1: HashStable<CTX>, CTX> HashStable<CTX> for (T1,) {
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fn hash_stable<W: StableHasherResult>(&self,
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ctx: &mut CTX,
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hasher: &mut StableHasher<W>) {
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let (ref _0,) = *self;
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_0.hash_stable(ctx, hasher);
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}
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}
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impl<T1: HashStable<CTX>, T2: HashStable<CTX>, CTX> HashStable<CTX> for (T1, T2) {
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fn hash_stable<W: StableHasherResult>(&self,
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ctx: &mut CTX,
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hasher: &mut StableHasher<W>) {
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let (ref _0, ref _1) = *self;
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_0.hash_stable(ctx, hasher);
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_1.hash_stable(ctx, hasher);
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}
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}
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impl<T1, T2, T3, CTX> HashStable<CTX> for (T1, T2, T3)
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where T1: HashStable<CTX>,
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T2: HashStable<CTX>,
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T3: HashStable<CTX>,
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{
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fn hash_stable<W: StableHasherResult>(&self,
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ctx: &mut CTX,
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hasher: &mut StableHasher<W>) {
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let (ref _0, ref _1, ref _2) = *self;
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_0.hash_stable(ctx, hasher);
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_1.hash_stable(ctx, hasher);
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_2.hash_stable(ctx, hasher);
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}
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}
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impl<T1, T2, T3, T4, CTX> HashStable<CTX> for (T1, T2, T3, T4)
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where T1: HashStable<CTX>,
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T2: HashStable<CTX>,
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T3: HashStable<CTX>,
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T4: HashStable<CTX>,
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{
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fn hash_stable<W: StableHasherResult>(&self,
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ctx: &mut CTX,
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hasher: &mut StableHasher<W>) {
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let (ref _0, ref _1, ref _2, ref _3) = *self;
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_0.hash_stable(ctx, hasher);
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_1.hash_stable(ctx, hasher);
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_2.hash_stable(ctx, hasher);
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_3.hash_stable(ctx, hasher);
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}
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}
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impl<T: HashStable<CTX>, CTX> HashStable<CTX> for [T] {
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default fn hash_stable<W: StableHasherResult>(&self,
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ctx: &mut CTX,
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hasher: &mut StableHasher<W>) {
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self.len().hash_stable(ctx, hasher);
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for item in self {
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item.hash_stable(ctx, hasher);
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}
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}
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}
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impl<T: HashStable<CTX>, CTX> HashStable<CTX> for Vec<T> {
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#[inline]
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fn hash_stable<W: StableHasherResult>(&self,
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ctx: &mut CTX,
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hasher: &mut StableHasher<W>) {
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(&self[..]).hash_stable(ctx, hasher);
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}
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}
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impl<T: ?Sized + HashStable<CTX>, CTX> HashStable<CTX> for Box<T> {
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#[inline]
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fn hash_stable<W: StableHasherResult>(&self,
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ctx: &mut CTX,
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hasher: &mut StableHasher<W>) {
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(**self).hash_stable(ctx, hasher);
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}
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}
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impl<T: ?Sized + HashStable<CTX>, CTX> HashStable<CTX> for ::std::rc::Rc<T> {
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#[inline]
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fn hash_stable<W: StableHasherResult>(&self,
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ctx: &mut CTX,
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hasher: &mut StableHasher<W>) {
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(**self).hash_stable(ctx, hasher);
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}
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}
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impl<T: ?Sized + HashStable<CTX>, CTX> HashStable<CTX> for ::std::sync::Arc<T> {
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#[inline]
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fn hash_stable<W: StableHasherResult>(&self,
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ctx: &mut CTX,
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hasher: &mut StableHasher<W>) {
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(**self).hash_stable(ctx, hasher);
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}
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}
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impl<CTX> HashStable<CTX> for str {
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#[inline]
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fn hash_stable<W: StableHasherResult>(&self,
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_: &mut CTX,
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hasher: &mut StableHasher<W>) {
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self.len().hash(hasher);
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self.as_bytes().hash(hasher);
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}
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}
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impl<CTX> HashStable<CTX> for String {
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#[inline]
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fn hash_stable<W: StableHasherResult>(&self,
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hcx: &mut CTX,
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hasher: &mut StableHasher<W>) {
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(&self[..]).hash_stable(hcx, hasher);
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}
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}
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impl<HCX> ToStableHashKey<HCX> for String {
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type KeyType = String;
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#[inline]
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fn to_stable_hash_key(&self, _: &HCX) -> Self::KeyType {
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self.clone()
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}
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}
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impl<CTX> HashStable<CTX> for bool {
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#[inline]
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fn hash_stable<W: StableHasherResult>(&self,
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ctx: &mut CTX,
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hasher: &mut StableHasher<W>) {
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(if *self { 1u8 } else { 0u8 }).hash_stable(ctx, hasher);
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}
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}
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impl<T, CTX> HashStable<CTX> for Option<T>
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where T: HashStable<CTX>
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{
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#[inline]
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fn hash_stable<W: StableHasherResult>(&self,
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ctx: &mut CTX,
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hasher: &mut StableHasher<W>) {
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if let Some(ref value) = *self {
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1u8.hash_stable(ctx, hasher);
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value.hash_stable(ctx, hasher);
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} else {
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0u8.hash_stable(ctx, hasher);
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}
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}
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}
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impl<T1, T2, CTX> HashStable<CTX> for Result<T1, T2>
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where T1: HashStable<CTX>,
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T2: HashStable<CTX>,
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{
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#[inline]
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fn hash_stable<W: StableHasherResult>(&self,
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ctx: &mut CTX,
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hasher: &mut StableHasher<W>) {
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mem::discriminant(self).hash_stable(ctx, hasher);
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match *self {
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Ok(ref x) => x.hash_stable(ctx, hasher),
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Err(ref x) => x.hash_stable(ctx, hasher),
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}
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}
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}
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impl<'a, T, CTX> HashStable<CTX> for &'a T
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where T: HashStable<CTX> + ?Sized
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{
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#[inline]
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fn hash_stable<W: StableHasherResult>(&self,
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ctx: &mut CTX,
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hasher: &mut StableHasher<W>) {
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(**self).hash_stable(ctx, hasher);
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}
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}
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impl<T, CTX> HashStable<CTX> for ::std::mem::Discriminant<T> {
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#[inline]
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fn hash_stable<W: StableHasherResult>(&self,
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_: &mut CTX,
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hasher: &mut StableHasher<W>) {
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::std::hash::Hash::hash(self, hasher);
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}
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}
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impl<I: indexed_vec::Idx, T, CTX> HashStable<CTX> for indexed_vec::IndexVec<I, T>
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where T: HashStable<CTX>,
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{
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fn hash_stable<W: StableHasherResult>(&self,
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ctx: &mut CTX,
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hasher: &mut StableHasher<W>) {
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self.len().hash_stable(ctx, hasher);
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for v in &self.raw {
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v.hash_stable(ctx, hasher);
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}
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}
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}
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impl<I: indexed_vec::Idx, CTX> HashStable<CTX> for bit_set::BitSet<I>
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{
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fn hash_stable<W: StableHasherResult>(&self,
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ctx: &mut CTX,
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hasher: &mut StableHasher<W>) {
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self.words().hash_stable(ctx, hasher);
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}
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}
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impl_stable_hash_via_hash!(::std::path::Path);
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impl_stable_hash_via_hash!(::std::path::PathBuf);
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impl<K, V, R, HCX> HashStable<HCX> for ::std::collections::HashMap<K, V, R>
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where K: ToStableHashKey<HCX> + Eq + Hash,
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V: HashStable<HCX>,
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R: BuildHasher,
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{
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#[inline]
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fn hash_stable<W: StableHasherResult>(&self,
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hcx: &mut HCX,
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hasher: &mut StableHasher<W>) {
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hash_stable_hashmap(hcx, hasher, self, ToStableHashKey::to_stable_hash_key);
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}
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}
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impl<K, R, HCX> HashStable<HCX> for ::std::collections::HashSet<K, R>
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where K: ToStableHashKey<HCX> + Eq + Hash,
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R: BuildHasher,
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{
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fn hash_stable<W: StableHasherResult>(&self,
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hcx: &mut HCX,
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hasher: &mut StableHasher<W>) {
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let mut keys: Vec<_> = self.iter()
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.map(|k| k.to_stable_hash_key(hcx))
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.collect();
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keys.sort_unstable();
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keys.hash_stable(hcx, hasher);
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}
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}
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impl<K, V, HCX> HashStable<HCX> for ::std::collections::BTreeMap<K, V>
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where K: ToStableHashKey<HCX>,
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V: HashStable<HCX>,
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{
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fn hash_stable<W: StableHasherResult>(&self,
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hcx: &mut HCX,
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hasher: &mut StableHasher<W>) {
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|
let mut entries: Vec<_> = self.iter()
|
|
.map(|(k, v)| (k.to_stable_hash_key(hcx), v))
|
|
.collect();
|
|
entries.sort_unstable_by(|&(ref sk1, _), &(ref sk2, _)| sk1.cmp(sk2));
|
|
entries.hash_stable(hcx, hasher);
|
|
}
|
|
}
|
|
|
|
impl<K, HCX> HashStable<HCX> for ::std::collections::BTreeSet<K>
|
|
where K: ToStableHashKey<HCX>,
|
|
{
|
|
fn hash_stable<W: StableHasherResult>(&self,
|
|
hcx: &mut HCX,
|
|
hasher: &mut StableHasher<W>) {
|
|
let mut keys: Vec<_> = self.iter()
|
|
.map(|k| k.to_stable_hash_key(hcx))
|
|
.collect();
|
|
keys.sort_unstable();
|
|
keys.hash_stable(hcx, hasher);
|
|
}
|
|
}
|
|
|
|
pub fn hash_stable_hashmap<HCX, K, V, R, SK, F, W>(
|
|
hcx: &mut HCX,
|
|
hasher: &mut StableHasher<W>,
|
|
map: &::std::collections::HashMap<K, V, R>,
|
|
to_stable_hash_key: F)
|
|
where K: Eq + Hash,
|
|
V: HashStable<HCX>,
|
|
R: BuildHasher,
|
|
SK: HashStable<HCX> + Ord + Clone,
|
|
F: Fn(&K, &HCX) -> SK,
|
|
W: StableHasherResult,
|
|
{
|
|
let mut entries: Vec<_> = map.iter()
|
|
.map(|(k, v)| (to_stable_hash_key(k, hcx), v))
|
|
.collect();
|
|
entries.sort_unstable_by(|&(ref sk1, _), &(ref sk2, _)| sk1.cmp(sk2));
|
|
entries.hash_stable(hcx, hasher);
|
|
}
|
|
|
|
|
|
/// A vector container that makes sure that its items are hashed in a stable
|
|
/// order.
|
|
pub struct StableVec<T>(Vec<T>);
|
|
|
|
impl<T> StableVec<T> {
|
|
pub fn new(v: Vec<T>) -> Self {
|
|
StableVec(v)
|
|
}
|
|
}
|
|
|
|
impl<T> ::std::ops::Deref for StableVec<T> {
|
|
type Target = Vec<T>;
|
|
|
|
fn deref(&self) -> &Vec<T> {
|
|
&self.0
|
|
}
|
|
}
|
|
|
|
impl<T, HCX> HashStable<HCX> for StableVec<T>
|
|
where T: HashStable<HCX> + ToStableHashKey<HCX>
|
|
{
|
|
fn hash_stable<W: StableHasherResult>(&self,
|
|
hcx: &mut HCX,
|
|
hasher: &mut StableHasher<W>) {
|
|
let StableVec(ref v) = *self;
|
|
|
|
let mut sorted: Vec<_> = v.iter()
|
|
.map(|x| x.to_stable_hash_key(hcx))
|
|
.collect();
|
|
sorted.sort_unstable();
|
|
sorted.hash_stable(hcx, hasher);
|
|
}
|
|
}
|