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