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};
21 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
27 /// Create a new `Svh` given the hash. If you actually want to
28 /// compute the SVH from some HIR, you want the `calculate_svh`
29 /// function found in `librustc_incremental`.
30 pub fn new(hash: u64) -> Svh {
34 pub fn as_u64(&self) -> u64 {
38 pub fn to_string(&self) -> String {
40 return (0..64).step_by(4).map(|i| hex(hash >> i)).collect();
42 fn hex(b: u64) -> char {
43 let b = (b & 0xf) as u8;
45 0 ... 9 => '0' as u8 + b,
46 _ => 'a' as u8 + b - 10,
54 fn hash<H>(&self, state: &mut H) where H: Hasher {
55 self.hash.to_le().hash(state);
59 impl fmt::Display for Svh {
60 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
61 f.pad(&self.to_string())