1 // Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 //! Calculation and management of a Strict Version Hash for crates
13 //! The SVH is used for incremental compilation to track when HIR
14 //! nodes have changed between compilations, and also to detect
15 //! mismatches where we have two versions of the same crate that were
16 //! compiled from distinct sources.
19 use std::hash::{Hash, Hasher};
20 use serialize::{Encodable, Decodable, Encoder, Decoder};
24 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
30 /// Create a new `Svh` given the hash. If you actually want to
31 /// compute the SVH from some HIR, you want the `calculate_svh`
32 /// function found in `librustc_incremental`.
33 pub fn new(hash: u64) -> Svh {
37 pub fn as_u64(&self) -> u64 {
41 pub fn to_string(&self) -> String {
42 format!("{:016x}", self.hash)
47 fn hash<H>(&self, state: &mut H) where H: Hasher {
48 self.hash.to_le().hash(state);
52 impl fmt::Display for Svh {
53 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
54 f.pad(&self.to_string())
58 impl Encodable for Svh {
59 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
60 s.emit_u64(self.as_u64().to_le())
64 impl Decodable for Svh {
65 fn decode<D: Decoder>(d: &mut D) -> Result<Svh, D::Error> {
72 impl<T> stable_hasher::HashStable<T> for Svh {
74 fn hash_stable<W: stable_hasher::StableHasherResult>(
77 hasher: &mut stable_hasher::StableHasher<W>
82 hash.hash_stable(ctx, hasher);