hash_types.rs

// Rust Bitcoin Library
// Written in 2014 by
//   Andrew Poelstra <apoelstra@wpsoftware.net>
//
// To the extent possible under law, the author(s) have dedicated all
// copyright and related and neighboring rights to this software to
// the public domain worldwide. This software is distributed without
// any warranty.
//
// You should have received a copy of the CC0 Public Domain Dedication
// along with this software.
// If not, see <http://creativecommons.org/publicdomain/zero/1.0/>.
//

//! Bitcoin hash types.
//!
//! This module defines types for hashes used throughout the library. These
//! types are needed in order to avoid mixing data of the same hash format
//! (e.g. `SHA256d`) but of different meaning (such as transaction id, block
//! hash).
//!

#[rustfmt::skip]
macro_rules! impl_hashencode {
    ($hashtype:ident) => {
        impl $crate::consensus::Encodable for $hashtype {
            fn consensus_encode<S: $crate::io::Write>(&self, s: S) -> Result<usize, $crate::io::Error> {
                self.0.consensus_encode(s)
            }
        }

        impl $crate::consensus::Decodable for $hashtype {
            fn consensus_decode<D: $crate::io::Read>(d: D) -> Result<Self, $crate::consensus::encode::Error> {
                use $crate::hashes::Hash;
                Ok(Self::from_inner(<<$hashtype as $crate::hashes::Hash>::Inner>::consensus_decode(d)?))
            }
        }
    };
}

// newtypes module is solely here so we can rustfmt::skip.
pub use newtypes::*;

#[rustfmt::skip]
mod newtypes {
    use crate::hashes::{Hash, sha256, sha256d, hash160, hash_newtype};

    hash_newtype!(
        Txid, sha256d::Hash, 32, doc="A bitcoin transaction hash/transaction ID.

For compatibility with the existing Bitcoin infrastructure and historical
and current versions of the Bitcoin Core software itself, this and
other [`sha256d::Hash`] types, are serialized in reverse
byte order when converted to a hex string via [`std::fmt::Display`] trait operations.
See [`hashes::Hash::DISPLAY_BACKWARD`] for more details.
");
    hash_newtype!(Wtxid, sha256d::Hash, 32, doc="A bitcoin witness transaction ID.");
    hash_newtype!(BlockHash, sha256d::Hash, 32, doc="A bitcoin block hash.");
    hash_newtype!(Sighash, sha256d::Hash, 32, doc="Hash of the transaction according to the signature algorithm");

    hash_newtype!(PubkeyHash, hash160::Hash, 20, doc="A hash of a public key.");
    hash_newtype!(ScriptHash, hash160::Hash, 20, doc="A hash of Bitcoin Script bytecode.");
    hash_newtype!(WPubkeyHash, hash160::Hash, 20, doc="SegWit version of a public key hash.");
    hash_newtype!(WScriptHash, sha256::Hash, 32, doc="SegWit version of a Bitcoin Script bytecode hash.");

    hash_newtype!(TxMerkleNode, sha256d::Hash, 32, doc="A hash of the Merkle tree branch or root for transactions");
    hash_newtype!(WitnessMerkleNode, sha256d::Hash, 32, doc="A hash corresponding to the Merkle tree root for witness data");
    hash_newtype!(WitnessCommitment, sha256d::Hash, 32, doc="A hash corresponding to the witness structure commitment in the coinbase transaction");
    hash_newtype!(XpubIdentifier, hash160::Hash, 20, doc="XpubIdentifier as defined in BIP-32.");

    hash_newtype!(FilterHash, sha256d::Hash, 32, doc="Filter hash, as defined in BIP-157");
    hash_newtype!(FilterHeader, sha256d::Hash, 32, doc="Filter header, as defined in BIP-157");

    impl_hashencode!(Txid);
    impl_hashencode!(Wtxid);
    impl_hashencode!(BlockHash);
    impl_hashencode!(Sighash);

    impl_hashencode!(TxMerkleNode);
    impl_hashencode!(WitnessMerkleNode);

    impl_hashencode!(FilterHash);
    impl_hashencode!(FilterHeader);
}