use hex::FromHex;
use md5::{digest::generic_array::GenericArray, Digest, Md5};
use sha1::Sha1;
use sha2::{Sha256, Sha512};
use std::{io, path::Path};
use thiserror::Error;
use crate::request::RequestChecksum;
#[derive(Debug, Error)]
pub enum ChecksumError {
#[error("checksum invalid: {0}")]
InvalidInput(String),
#[error("unable to open the file to validate")]
FileOpen(#[source] io::Error),
#[error(
"file does not match expected size: found {} KiB but expected {} KiB",
found,
expected
)]
InvalidSize { found: u64, expected: u64 },
#[error("error during read of file")]
FileRead(#[source] io::Error),
#[error("checksum mismatch")]
Mismatch,
}
pub fn compare_hash(
path: &Path,
expected_size: u64,
expected_hash: &RequestChecksum,
) -> Result<(), ChecksumError> {
use std::io::Read;
let mut file = std::fs::File::open(path).map_err(ChecksumError::FileOpen)?;
let file_size = file.metadata().unwrap().len();
if file_size != expected_size {
return Err(ChecksumError::InvalidSize {
found: file_size / 1024,
expected: expected_size / 1024,
});
}
match expected_hash {
RequestChecksum::Md5(sum) => {
let expected = <[u8; 16]>::from_hex(sum)
.map(GenericArray::from)
.map_err(|_| ChecksumError::InvalidInput(format!("MD5 {}", sum)))?;
let mut buffer = vec![0u8; 8 * 1024];
let mut hasher = Md5::new();
loop {
match file.read(&mut buffer) {
Ok(0) => break,
Ok(bytes) => hasher.update(&buffer[..bytes]),
Err(why) => return Err(ChecksumError::FileRead(why)),
}
}
let hash = &*hasher.finalize();
if &*expected == hash {
Ok(())
} else {
Err(ChecksumError::Mismatch)
}
}
RequestChecksum::Sha1(sum) => {
let expected = <[u8; 20]>::from_hex(sum)
.map(GenericArray::from)
.map_err(|_| ChecksumError::InvalidInput(format!("SHA1 {}", sum)))?;
let mut buffer = vec![0u8; 8 * 1024];
let mut hasher = Sha1::new();
loop {
match file.read(&mut buffer) {
Ok(0) => break,
Ok(bytes) => hasher.update(&buffer[..bytes]),
Err(why) => return Err(ChecksumError::FileRead(why)),
}
}
let hash = &*hasher.finalize();
if &*expected == hash {
Ok(())
} else {
Err(ChecksumError::Mismatch)
}
}
RequestChecksum::Sha256(sum) => {
let expected = <[u8; 32]>::from_hex(sum)
.map(GenericArray::from)
.map_err(|_| ChecksumError::InvalidInput(format!("SHA256 {}", sum)))?;
let mut buffer = vec![0u8; 8 * 1024];
let mut hasher = Sha256::new();
loop {
match file.read(&mut buffer) {
Ok(0) => break,
Ok(bytes) => hasher.update(&buffer[..bytes]),
Err(why) => return Err(ChecksumError::FileRead(why)),
}
}
let hash = &*hasher.finalize();
if &*expected == hash {
Ok(())
} else {
Err(ChecksumError::Mismatch)
}
}
RequestChecksum::Sha512(sum) => {
let expected = <[u8; 64]>::from_hex(sum)
.map(GenericArray::from)
.map_err(|_| ChecksumError::InvalidInput(format!("SHA512 {}", sum)))?;
let mut buffer = vec![0u8; 8 * 1024];
let mut hasher = Sha512::new();
loop {
match file.read(&mut buffer) {
Ok(0) => break,
Ok(bytes) => hasher.update(&buffer[..bytes]),
Err(why) => return Err(ChecksumError::FileRead(why)),
}
}
let hash = &*hasher.finalize();
if &*expected == hash {
Ok(())
} else {
Err(ChecksumError::Mismatch)
}
}
}
}