1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136

use std::{fs::File, io::Read, path::Path};

use multihash::Code;
pub use multihash::{Hasher, Multihash, MultihashDigest, Sha3_256, Sha3_512, StatefulHasher};

use crate::framing;

const MULTIHASH_CODE_SIZE: usize = 2;

/// Multihash digest extension.
pub trait MultihashDigestExt: StatefulHasher + Default {
    fn input_signed_frame<I: framing::FrameReader>(
        &mut self,
        frame: &framing::MultihashFrame<Self, I>,
    ) {
        self.update(frame.multihash_bytes());
    }

    fn multihash_size() -> usize {
        MULTIHASH_CODE_SIZE + usize::from(Self::size())
    }

    fn to_multihash(&self) -> Multihash;

    fn update_from_reader<R: Read>(&mut self, mut read: R) -> Result<Multihash, std::io::Error> {
        let mut bytes = Vec::new();
        read.read_to_end(&mut bytes)?;

        self.update(&bytes);
        Ok(self.to_multihash())
    }
}

impl<T> MultihashDigestExt for T
where
    T: StatefulHasher,
    Code: for<'a> From<&'a T::Digest>,
{
    fn to_multihash(&self) -> Multihash {
        let digest = self.finalize();
        Code::multihash_from_digest(&digest)
    }
}

pub trait MultihashExt {
    fn encode_bs58(&self) -> String;
}

impl MultihashExt for Multihash {
    fn encode_bs58(&self) -> String {
        bs58::encode(self.to_bytes()).into_string()
    }
}

pub fn multihash_decode_bs58(str: &str) -> Result<Multihash, HashError> {
    let bytes = bs58::decode(str).into_vec()?;
    let mh = Multihash::from_bytes(&bytes)?;
    Ok(mh)
}

pub fn multihash_sha3_256_file<P: AsRef<Path>>(path: P) -> Result<Multihash, HashError> {
    let file = File::open(path.as_ref())?;
    let mut digest = Sha3_256::default();
    let mh = digest.update_from_reader(file)?;
    Ok(mh)
}

#[derive(thiserror::Error, Debug)]
pub enum HashError {
    #[error("Base58 decoding error: {0}")]
    Bs58(#[from] bs58::decode::Error),
    #[error("Multihash error: {0}")]
    Multihash(#[from] multihash::Error),
    #[error("IO error: {0}")]
    Io(#[from] std::io::Error),
}

#[cfg(test)]
mod tests {
    use std::io::{Seek, SeekFrom, Write};

    use tempfile::tempdir;

    use super::*;

    #[test]
    fn test_to_multihash() {
        let stateless = Code::Sha3_256.digest(b"Hello world");

        let mut hasher = Sha3_256::default();
        hasher.update(b"Hello world");
        let stateful = hasher.to_multihash();

        assert_eq!(stateful, stateless);
    }

    #[test]
    fn multihash_from_reader() {
        let stateless = Code::Sha3_256.digest(b"Hello world");

        let mut file = tempfile::tempfile().unwrap();
        file.write_all(b"Hello world").unwrap();
        file.seek(SeekFrom::Start(0)).unwrap();

        let mut hasher = Sha3_256::default();
        hasher.update_from_reader(file).unwrap();
        let file_hash = hasher.to_multihash();

        assert_eq!(stateless, file_hash);
    }

    #[test]
    fn bs58_encode_decode() {
        let mh_init = Code::Sha3_256.digest(b"Hello world");

        let bs58 = mh_init.encode_bs58();
        let mh_decoded = multihash_decode_bs58(&bs58).unwrap();
        assert_eq!(mh_init, mh_decoded);
    }

    #[test]
    fn multihash_file() {
        let dir = tempdir().unwrap();
        let file_path = dir.path().join("file.txt");

        {
            let mut file = File::create(&file_path).unwrap();
            file.write_all(b"Hello world").unwrap();
        }

        let file_hash = multihash_sha3_256_file(file_path).unwrap();
        let hw_hash = Code::Sha3_256.digest(b"Hello world");

        assert_eq!(hw_hash, file_hash);
    }
}