holochain_persistence_api 0.0.10

//! The HashString type is defined here. It is used for type safety throughout the codebase
//! to keep track of places where a string is the product of a hash function,
//! and as a base type for Address to use.

use crate::holochain_json_api::{error::JsonError, json::JsonString};
use multihash::{encode, Hash};
use rust_base58::{FromBase58, ToBase58};
use std::{convert::TryInto, fmt};

// HashString newtype for String
#[derive(
    PartialOrd, PartialEq, Eq, Ord, Clone, Debug, Serialize, Deserialize, DefaultJson, Default, Hash,
)]
pub struct HashString(String);

impl fmt::Display for HashString {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, "{}", self.0)
    }
}

impl From<String> for HashString {
    fn from(s: String) -> HashString {
        HashString(s)
    }
}

impl From<HashString> for String {
    fn from(h: HashString) -> String {
        h.0
    }
}

impl<'a> From<&'a str> for HashString {
    fn from(s: &str) -> HashString {
        HashString::from(s.to_string())
    }
}

impl<'a> From<&Vec<u8>> for HashString {
    fn from(v: &Vec<u8>) -> HashString {
        HashString::from(v.clone())
    }
}

impl From<Vec<u8>> for HashString {
    fn from(v: Vec<u8>) -> HashString {
        HashString::from(v.to_base58())
    }
}

impl TryInto<Vec<u8>> for HashString {
    type Error = rust_base58::base58::FromBase58Error;
    fn try_into(self) -> Result<Vec<u8>, Self::Error> {
        self.0.from_base58()
    }
}

impl<'a> TryInto<Vec<u8>> for &'a HashString {
    type Error = rust_base58::base58::FromBase58Error;
    fn try_into(self) -> Result<Vec<u8>, Self::Error> {
        self.clone().try_into()
    }
}

impl<'a> AsRef<[u8]> for HashString {
    fn as_ref(&self) -> &[u8] {
        self.0.as_bytes()
    }
}

impl HashString {
    pub fn new() -> HashString {
        HashString("".to_string())
    }

    /// convert bytes to a b58 hashed string
    pub fn encode_from_bytes(bytes: &[u8], hash_type: Hash) -> HashString {
        HashString::from(encode(hash_type, bytes).unwrap().to_base58())
    }

    /// convert a string as bytes to a b58 hashed string
    pub fn encode_from_str(s: &str, hash_type: Hash) -> HashString {
        HashString::encode_from_bytes(s.as_bytes(), hash_type)
    }

    /// magic all in one fn, take a JsonString + hash type and get a hashed b58 string back
    pub fn encode_from_json_string(json_string: JsonString, hash_type: Hash) -> HashString {
        HashString::encode_from_str(&String::from(json_string), hash_type)
    }
}

#[cfg(test)]
pub mod tests {
    use super::*;
    use crate::fixture::{test_entry_a, test_hash_a};
    use cas::content::AddressableContent;
    use multihash::Hash;

    #[test]
    /// show From<String> implementation
    fn from_string_test() {
        assert_eq!(HashString::new(), HashString::from("".to_string()),);

        assert_eq!(
            test_hash_a(),
            HashString::from(test_entry_a().address().to_string()),
        );
    }

    #[test]
    /// show From<&str> implementation
    fn from_str_test() {
        assert_eq!(HashString::new(), HashString::from(""));

        assert_eq!(test_hash_a(), HashString::from(test_entry_a().address()),);
    }

    #[test]
    /// mimics tests from legacy golang holochain core hashing bytes
    fn bytes_to_b58_known_golang() {
        assert_eq!(
            HashString::encode_from_bytes(b"test data", Hash::SHA2256).to_string(),
            "QmY8Mzg9F69e5P9AoQPYat655HEhc1TVGs11tmfNSzkqh2"
        )
    }

    #[test]
    /// mimics tests from legacy golang holochain core hashing strings
    fn str_to_b58_hash_known_golang() {
        assert_eq!(
            HashString::encode_from_str("test data", Hash::SHA2256).to_string(),
            "QmY8Mzg9F69e5P9AoQPYat655HEhc1TVGs11tmfNSzkqh2"
        );
    }

    #[test]
    /// known hash for a serializable something
    fn can_serialize_to_b58_hash() {
        #[derive(Serialize, Deserialize, Debug, DefaultJson)]
        struct Foo {
            foo: u8,
        };

        assert_eq!(
            "Qme7Bu4NVYMtpsRtb7e4yyhcbE1zdB9PsrKTdosaqF3Bu3",
            HashString::encode_from_json_string(JsonString::from(Foo { foo: 5 }), Hash::SHA2256)
                .to_string(),
        );
    }

    #[test]
    fn can_convert_vec_u8_to_hash() {
        let v: Vec<u8> = vec![48, 49, 50];
        let hash_string: HashString = v.clone().into();
        assert_eq!("HBrq", hash_string.to_string());
        let hash_string_from_ref: HashString = (&v).into();
        assert_eq!("HBrq", hash_string_from_ref.to_string());
        let result: Result<Vec<u8>, _> = hash_string.clone().try_into();
        assert!(result.is_ok());
        assert_eq!(result.unwrap(), [48, 49, 50]);
        let result_from_ref: Result<Vec<u8>, _> = (&hash_string).try_into();
        assert!(result_from_ref.is_ok());
        assert_eq!(result_from_ref.unwrap(), [48, 49, 50]);
    }
}