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Deprecate bip143::SigHashCache in favor of sighash::SigHashCache
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@RCasatta
RCasatta committed Jul 21, 2021
1 parent 15e3caf commit 53d0e17
Showing 1 changed file with 15 additions and 100 deletions.
115 changes: 15 additions & 100 deletions src/util/bip143.rs
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Expand Up @@ -19,7 +19,7 @@
//! signatures, which are placed in the scriptSig.
//!

use hashes::{Hash, sha256d};
use hashes::Hash;
use hash_types::SigHash;
use blockdata::script::Script;
use blockdata::transaction::{Transaction, TxIn, SigHashType};
Expand All @@ -29,11 +29,12 @@ use prelude::*;

use io;
use core::ops::{Deref, DerefMut};
use util::sighash;

/// Parts of a sighash which are common across inputs or signatures, and which are
/// sufficient (in conjunction with a private key) to sign the transaction
#[derive(Clone, PartialEq, Eq, Debug)]
#[deprecated(since="0.24.0", note="please use `SigHashCache` instead")]
#[deprecated(since="0.24.0", note="please use [sighash::SigHashCache] instead")]
pub struct SighashComponents {
tx_version: i32,
tx_locktime: u32,
Expand Down Expand Up @@ -107,121 +108,34 @@ impl SighashComponents {
}

/// A replacement for SigHashComponents which supports all sighash modes
#[deprecated(since="0.27.0", note="please use [sighash::SigHashCache] instead")]
pub struct SigHashCache<R: Deref<Target=Transaction>> {
/// Access to transaction required for various introspection
tx: R,
/// Hash of all the previous outputs, computed as required
hash_prevouts: Option<sha256d::Hash>,
/// Hash of all the input sequence nos, computed as required
hash_sequence: Option<sha256d::Hash>,
/// Hash of all the outputs in this transaction, computed as required
hash_outputs: Option<sha256d::Hash>,
cache: sighash::SigHashCache<R>,
}

#[allow(deprecated)]
impl<R: Deref<Target=Transaction>> SigHashCache<R> {
/// Compute the sighash components from an unsigned transaction and auxiliary
/// in a lazy manner when required.
/// For the generated sighashes to be valid, no fields in the transaction may change except for
/// script_sig and witnesses.
pub fn new(tx: R) -> Self {
SigHashCache {
tx: tx,
hash_prevouts: None,
hash_sequence: None,
hash_outputs: None,
}
}

/// Calculate hash for prevouts
pub fn hash_prevouts(&mut self) -> sha256d::Hash {
let hash_prevout = &mut self.hash_prevouts;
let input = &self.tx.input;
*hash_prevout.get_or_insert_with(|| {
let mut enc = sha256d::Hash::engine();
for txin in input {
txin.previous_output.consensus_encode(&mut enc).unwrap();
}
sha256d::Hash::from_engine(enc)
})
}

/// Calculate hash for input sequence values
pub fn hash_sequence(&mut self) -> sha256d::Hash {
let hash_sequence = &mut self.hash_sequence;
let input = &self.tx.input;
*hash_sequence.get_or_insert_with(|| {
let mut enc = sha256d::Hash::engine();
for txin in input {
txin.sequence.consensus_encode(&mut enc).unwrap();
}
sha256d::Hash::from_engine(enc)
})
}

/// Calculate hash for outputs
pub fn hash_outputs(&mut self) -> sha256d::Hash {
let hash_output = &mut self.hash_outputs;
let output = &self.tx.output;
*hash_output.get_or_insert_with(|| {
let mut enc = sha256d::Hash::engine();
for txout in output {
txout.consensus_encode(&mut enc).unwrap();
}
sha256d::Hash::from_engine(enc)
})
Self { cache: sighash::SigHashCache::new(tx) }
}

/// Encode the BIP143 signing data for any flag type into a given object implementing a
/// std::io::Write trait.
pub fn encode_signing_data_to<Write: io::Write>(
&mut self,
mut writer: Write,
writer: Write,
input_index: usize,
script_code: &Script,
value: u64,
sighash_type: SigHashType,
) -> Result<(), encode::Error> {
let zero_hash = sha256d::Hash::default();

let (sighash, anyone_can_pay) = sighash_type.split_anyonecanpay_flag();

self.tx.version.consensus_encode(&mut writer)?;

if !anyone_can_pay {
self.hash_prevouts().consensus_encode(&mut writer)?;
} else {
zero_hash.consensus_encode(&mut writer)?;
}

if !anyone_can_pay && sighash != SigHashType::Single && sighash != SigHashType::None {
self.hash_sequence().consensus_encode(&mut writer)?;
} else {
zero_hash.consensus_encode(&mut writer)?;
}

{
let txin = &self.tx.input[input_index];

txin
.previous_output
.consensus_encode(&mut writer)?;
script_code.consensus_encode(&mut writer)?;
value.consensus_encode(&mut writer)?;
txin.sequence.consensus_encode(&mut writer)?;
}

if sighash != SigHashType::Single && sighash != SigHashType::None {
self.hash_outputs().consensus_encode(&mut writer)?;
} else if sighash == SigHashType::Single && input_index < self.tx.output.len() {
let mut single_enc = SigHash::engine();
self.tx.output[input_index].consensus_encode(&mut single_enc)?;
SigHash::from_engine(single_enc).consensus_encode(&mut writer)?;
} else {
zero_hash.consensus_encode(&mut writer)?;
}

self.tx.lock_time.consensus_encode(&mut writer)?;
sighash_type.as_u32().consensus_encode(&mut writer)?;
self.cache
.segwit_encode_signing_data_to(writer, input_index, script_code, value, sighash_type.into())
.expect("input_index greater than tx input len");
Ok(())
}

Expand All @@ -241,6 +155,7 @@ impl<R: Deref<Target=Transaction>> SigHashCache<R> {
}
}

#[allow(deprecated)]
impl<R: DerefMut<Target=Transaction>> SigHashCache<R> {
/// When the SigHashCache is initialized with a mutable reference to a transaction instead of a
/// regular reference, this method is available to allow modification to the witnesses.
Expand All @@ -263,13 +178,14 @@ impl<R: DerefMut<Target=Transaction>> SigHashCache<R> {
/// }
/// ```
pub fn access_witness(&mut self, input_index: usize) -> &mut Vec<Vec<u8>> {
&mut self.tx.input[input_index].witness
self.cache.access_witness(input_index)
}
}

#[cfg(test)]
#[allow(deprecated)]
mod tests {
use std::str::FromStr;
use hash_types::SigHash;
use blockdata::script::Script;
use blockdata::transaction::Transaction;
Expand All @@ -282,8 +198,7 @@ mod tests {
use super::*;

fn p2pkh_hex(pk: &str) -> Script {
let pk = Vec::from_hex(pk).unwrap();
let pk = PublicKey::from_slice(pk.as_slice()).unwrap();
let pk: PublicKey = PublicKey::from_str(pk).unwrap();
let witness_script = Address::p2pkh(&pk, Network::Bitcoin).script_pubkey();
witness_script
}
Expand Down

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