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Merge rust-bitcoin/rust-bitcoin#864: Cleanup block module 

146d5e83d1 Improve docs for blockdata::block (Tobin Harding)
f03092c380 Fix erroneous function rustdoc (Tobin Harding)
5464848f45 Refactor check_witness_commitment (Tobin Harding)

Pull request description:

  Do some clean ups to the `blockdata::block` module.

  - Patch 1: Change predicate names (API breaking, could be seen as unnecessarily changing the API), can remove if NACK'd
  - Patch 2: Refactor to assist code clarity
  - Patch 3 and 4: are docs improvements, shouldn't be too controversial

ACKs for top commit:
  apoelstra:
    ACK 146d5e83d1
  dr-orlovsky:
    ACK 146d5e83d1

Tree-SHA512: 65cc414857c4569a389638b53eb99ed629bf67ae1d8ebdc9023e5974bb26902d4de41ec311bef3b5c895229d7d0df78d469a84c1e94fc0b7be7435338f0d510a
This commit is contained in:
Dr. Maxim Orlovsky 2022-03-12 12:40:08 +02:00
parent 501cf63f0d 146d5e83d1
commit 7e755d3ddd
No known key found for this signature in database
GPG Key ID: AF91255DEA466640
1 changed files with 39 additions and 36 deletions
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65
src/blockdata/block.rs
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@ -44,30 +44,30 @@ use VarInt;
pub struct BlockHeader {
/// The protocol version. Should always be 1.
pub version: i32,
/// Reference to the previous block in the chain
/// Reference to the previous block in the chain.
pub prev_blockhash: BlockHash,
/// The root hash of the merkle tree of transactions in the block
/// The root hash of the merkle tree of transactions in the block.
pub merkle_root: TxMerkleNode,
/// The timestamp of the block, as claimed by the miner
/// The timestamp of the block, as claimed by the miner.
pub time: u32,
/// The target value below which the blockhash must lie, encoded as a
/// a float (with well-defined rounding, of course)
/// a float (with well-defined rounding, of course).
pub bits: u32,
/// The nonce, selected to obtain a low enough blockhash
/// The nonce, selected to obtain a low enough blockhash.
pub nonce: u32,
}
impl_consensus_encoding!(BlockHeader, version, prev_blockhash, merkle_root, time, bits, nonce);
impl BlockHeader {
/// Return the block hash.
/// Returns the block hash.
pub fn block_hash(&self) -> BlockHash {
let mut engine = BlockHash::engine();
self.consensus_encode(&mut engine).expect("engines don't error");
BlockHash::from_engine(engine)
}
/// Computes the target [0, T] that a blockhash must land in to be valid
/// Computes the target [0, T] that a blockhash must land in to be valid.
pub fn target(&self) -> Uint256 {
Self::u256_from_compact_target(self.bits)
}
@ -125,7 +125,7 @@ impl BlockHeader {
compact | (size << 24) as u32
}
/// Compute the popular "difficulty" measure for mining
/// Computes the popular "difficulty" measure for mining.
pub fn difficulty(&self, network: Network) -> u64 {
(max_target(network) / self.target()).low_u64()
}
@ -143,7 +143,7 @@ impl BlockHeader {
if hash <= target { Ok(block_hash) } else { Err(BlockBadProofOfWork) }
}
/// Returns the total work of the block
/// Returns the total work of the block.
pub fn work(&self) -> Uint256 {
// 2**256 / (target + 1) == ~target / (target+1) + 1 (eqn shamelessly stolen from bitcoind)
let mut ret = !self.target();
@ -169,7 +169,7 @@ pub struct Block {
impl_consensus_encoding!(Block, header, txdata);
impl Block {
/// Return the block hash.
/// Returns the block hash.
pub fn block_hash(&self) -> BlockHash {
self.header.block_hash()
}
@ -182,37 +182,41 @@ impl Block {
}
}
/// check if witness commitment in coinbase is matching the transaction list
/// Checks if witness commitment in coinbase matches the transaction list.
pub fn check_witness_commitment(&self) -> bool {
// witness commitment is optional if there are no transactions using SegWit in the block
const MAGIC: [u8; 6] = [0x6a, 0x24, 0xaa, 0x21, 0xa9, 0xed];
// Witness commitment is optional if there are no transactions using SegWit in the block.
if self.txdata.iter().all(|t| t.input.iter().all(|i| i.witness.is_empty())) {
return true;
}
if !self.txdata.is_empty() {
if self.txdata.is_empty() {
return false;
}
let coinbase = &self.txdata[0];
if coinbase.is_coin_base() {
// commitment is in the last output that starts with below magic
if !coinbase.is_coin_base() {
return false;
}
// Commitment is in the last output that starts with magic bytes.
if let Some(pos) = coinbase.output.iter()
.rposition(|o| {
o.script_pubkey.len () >= 38
&& o.script_pubkey[0..6] == [0x6a, 0x24, 0xaa, 0x21, 0xa9, 0xed] }) {
.rposition(|o| o.script_pubkey.len () >= 38 && o.script_pubkey[0..6] == MAGIC)
{
let commitment = WitnessCommitment::from_slice(&coinbase.output[pos].script_pubkey.as_bytes()[6..38]).unwrap();
// witness reserved value is in coinbase input witness
// Witness reserved value is in coinbase input witness.
let witness_vec: Vec<_> = coinbase.input[0].witness.iter().collect();
if witness_vec.len() == 1 && witness_vec[0].len() == 32 {
match self.witness_root() {
Some(witness_root) => return commitment == Self::compute_witness_commitment(&witness_root, witness_vec[0]),
None => return false,
}
}
if let Some(witness_root) = self.witness_root() {
return commitment == Self::compute_witness_commitment(&witness_root, witness_vec[0]);
}
}
}
false
}
/// Compute the transaction merkle root.
/// Computes the transaction merkle root.
pub fn compute_merkle_root(&self) -> Option<TxMerkleNode> {
let hashes = self.txdata.iter().map(|obj| obj.txid().as_hash());
bitcoin_merkle_root(hashes).map(|h| h.into())
@ -224,7 +228,7 @@ impl Block {
self.compute_merkle_root()
}
/// compute witness commitment for the transaction list
/// Computes the witness commitment for the block's transaction list.
pub fn compute_witness_commitment (witness_root: &WitnessMerkleNode, witness_reserved_value: &[u8]) -> WitnessCommitment {
let mut encoder = WitnessCommitment::engine();
witness_root.consensus_encode(&mut encoder).expect("engines don't error");
@ -232,7 +236,7 @@ impl Block {
WitnessCommitment::from_engine(encoder)
}
/// Merkle root of transactions hashed for witness
/// Computes the merkle root of transactions hashed for witness.
pub fn witness_root(&self) -> Option<WitnessMerkleNode> {
let hashes = self.txdata.iter().enumerate().map(|(i, t)|
if i == 0 {
@ -270,13 +274,12 @@ impl Block {
base_weight + txs_weight
}
/// Get the coinbase transaction, if one is present.
/// Returns the coinbase transaction, if one is present.
pub fn coinbase(&self) -> Option<&Transaction> {
self.txdata.first()
}
/// Get the block height as encoded into the coinbase according to BIP34.
/// Returns [None] if not present.
/// Returns the block height, as encoded in the coinbase transaction according to BIP34.
pub fn bip34_block_height(&self) -> Result<u64, Bip34Error> {
// Citing the spec:
// Add height as the first item in the coinbase transaction's scriptSig,