imag/libimagref/src/hasher.rs

48 lines
1.1 KiB
Rust

use std::path::PathBuf;
use std::io::Read;
use error::RefErrorKind as REK;
use error::MapErrInto;
use crypto::sha1::Sha1;
use crypto::digest::Digest;
use result::Result;
/// The Hasher trait is used to implement custom hashing functions for the ref library.
/// This means that one can define how the hash of a reference is constructed from the content of
/// the file to ref to.
pub trait Hasher {
fn hash_name(&self) -> &'static str;
fn create_hash<R: Read>(&mut self, pb: &PathBuf, contents: &mut R) -> Result<String>;
}
pub struct DefaultHasher {
hasher: Sha1,
}
impl DefaultHasher {
pub fn new() -> DefaultHasher {
DefaultHasher { hasher: Sha1::new() }
}
}
impl Hasher for DefaultHasher {
fn hash_name(&self) -> &'static str {
"default"
}
fn create_hash<R: Read>(&mut self, _: &PathBuf, c: &mut R) -> Result<String> {
let mut s = String::new();
try!(c.read_to_string(&mut s).map_err_into(REK::UTF8Error).map_err_into(REK::IOError));
self.hasher.input_str(&s[..]);
Ok(self.hasher.result_str())
}
}