71 lines
1.7 KiB
Rust
71 lines
1.7 KiB
Rust
//! Calculation and management of a Strict Version Hash for crates
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//!
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//! The SVH is used for incremental compilation to track when HIR
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//! nodes have changed between compilations, and also to detect
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//! mismatches where we have two versions of the same crate that were
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//! compiled from distinct sources.
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use std::fmt;
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use std::hash::{Hash, Hasher};
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use rustc_serialize::{Encodable, Decodable, Encoder, Decoder};
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use crate::stable_hasher;
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#[derive(Copy, Clone, PartialEq, Eq, Debug)]
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pub struct Svh {
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hash: u64,
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}
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impl Svh {
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/// Creates a new `Svh` given the hash. If you actually want to
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/// compute the SVH from some HIR, you want the `calculate_svh`
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/// function found in `librustc_incremental`.
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pub fn new(hash: u64) -> Svh {
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Svh { hash }
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}
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pub fn as_u64(&self) -> u64 {
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self.hash
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}
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pub fn to_string(&self) -> String {
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format!("{:016x}", self.hash)
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}
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}
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impl Hash for Svh {
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fn hash<H>(&self, state: &mut H) where H: Hasher {
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self.hash.to_le().hash(state);
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}
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}
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impl fmt::Display for Svh {
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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f.pad(&self.to_string())
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}
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}
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impl Encodable for Svh {
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fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
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s.emit_u64(self.as_u64().to_le())
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}
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}
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impl Decodable for Svh {
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fn decode<D: Decoder>(d: &mut D) -> Result<Svh, D::Error> {
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d.read_u64()
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.map(u64::from_le)
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.map(Svh::new)
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}
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}
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impl<T> stable_hasher::HashStable<T> for Svh {
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#[inline]
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fn hash_stable(&self, ctx: &mut T, hasher: &mut stable_hasher::StableHasher) {
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let Svh {
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hash
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} = *self;
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hash.hash_stable(ctx, hasher);
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}
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}
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