Closed
Description
There is a possible bug when you define a generic trait implementation within a different module but within the same file, e.g. given:
type byte = u8;
mod crypto {
// Hash is the trait implemented by all cryptographic hash functions.
pub trait Hash {
fn block_size() -> int;
fn digest() -> ~[byte];
fn digest_size() -> int;
fn reset();
fn update(msg: &[byte]);
}
// HashUtil is a utility trait that is auto-implemented for all Hash
// implementations.
pub trait HashUtil {
fn hexdigest() -> ~str;
fn update(msg: &str);
}
impl <A: Hash> A: HashUtil {
fn hexdigest() -> ~str {
let mut d = ~"";
for vec::each(self.digest()) |b| {
d += fmt!("%02x", *b as uint)
}
return d;
}
fn update(msg: &str) {
self.update(str::to_bytes(msg));
}
}
}
mod sha256 {
use crypto::Hash;
const block_size: int = 64;
const digest_size: int = 32;
const i0: u32 = 0x6a09e667;
const i1: u32 = 0xbb67ae85;
const i2: u32 = 0x3c6ef372;
const i3: u32 = 0xa54ff53a;
const i4: u32 = 0x510e527f;
const i5: u32 = 0x9b05688c;
const i6: u32 = 0x1f83d9ab;
const i7: u32 = 0x5be0cd19;
const k: [u32 * 64] =
[0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1,
0x923f82a4, 0xab1c5ed5, 0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174, 0xe49b69c1, 0xefbe4786,
0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147,
0x06ca6351, 0x14292967, 0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85, 0xa2bfe8a1, 0xa81a664b,
0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a,
0x5b9cca4f, 0x682e6ff3, 0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2];
struct sha256 {
b: [mut byte * 64],
h: [mut u32 * 8],
mut l: u64,
mut n: uint,
}
impl sha256 {
#[inline(always)]
fn compute_block() {
let mut h0 = self.h[0];
let mut h1 = self.h[1];
let mut h2 = self.h[2];
let mut h3 = self.h[3];
let mut h4 = self.h[4];
let mut h5 = self.h[5];
let mut h6 = self.h[6];
let mut h7 = self.h[7];
self.h[0] = h0;
self.h[1] = h1;
self.h[2] = h2;
self.h[3] = h3;
self.h[4] = h4;
self.h[5] = h5;
self.h[6] = h6;
self.h[7] = h7;
}
}
impl sha256: Hash {
fn block_size() -> int { block_size }
fn digest() -> ~[byte] {
~[1, 2, 37]
}
fn digest_size() -> int { digest_size }
fn reset() {
self.h[0] = i0;
self.h[1] = i1;
self.h[2] = i2;
self.h[3] = i3;
self.h[4] = i4;
self.h[5] = i5;
self.h[6] = i6;
self.h[7] = i7;
self.l = 0;
self.n = 0;
}
fn update(msg: &[byte]) {
let mut l = msg.len();
self.l += l as u64;
if self.n > 0 {
if l > 64 - self.n {
l = 64 - self.n;
}
}
}
}
pub fn new() -> sha256 {
sha256{
b: [mut 0, ..64],
h: [mut i0, i1, i2, i3, i4, i5, i6, i7],
l: 0,
n: 0
}
}
}
fn main() {
io::println(fmt!("val: %?", sha256::new().block_size()));
io::println(fmt!("val: %?", sha256::new().hexdigest()));
}The compiler errors with:
error: attempted access of field `hexdigest` on type `sha256::sha256`, but no field or method with that name was found
If, however, you put a use crypto::*; statement before the main(), then everything seems to work. This behaviour feels like a bug since block_size() works and hexdigest() is defined within the same module...