Converting LeafVersion into an enum

This commit is contained in:
Dr Maxim Orlovsky 2021-11-25 00:01:21 +01:00
parent 2405417432
commit 67b8db05a8
3 changed files with 44 additions and 31 deletions

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@ -235,7 +235,7 @@ impl Serialize for (Script, LeafVersion) {
fn serialize(&self) -> Vec<u8> { fn serialize(&self) -> Vec<u8> {
let mut buf = Vec::with_capacity(self.0.len() + 1); let mut buf = Vec::with_capacity(self.0.len() + 1);
buf.extend(self.0.as_bytes()); buf.extend(self.0.as_bytes());
buf.push(self.1.as_u8()); buf.push(self.1.into_consensus());
buf buf
} }
} }
@ -247,7 +247,7 @@ impl Deserialize for (Script, LeafVersion) {
} }
// The last byte is LeafVersion. // The last byte is LeafVersion.
let script = Script::deserialize(&bytes[..bytes.len() - 1])?; let script = Script::deserialize(&bytes[..bytes.len() - 1])?;
let leaf_ver = LeafVersion::from_u8(bytes[bytes.len() - 1]) let leaf_ver = LeafVersion::from_consensus(bytes[bytes.len() - 1])
.map_err(|_| encode::Error::ParseFailed("invalid leaf version"))?; .map_err(|_| encode::Error::ParseFailed("invalid leaf version"))?;
Ok((script, leaf_ver)) Ok((script, leaf_ver))
} }
@ -283,7 +283,7 @@ impl Serialize for TapTree {
// TaprootMerkleBranch can only have len atmost 128(TAPROOT_CONTROL_MAX_NODE_COUNT). // TaprootMerkleBranch can only have len atmost 128(TAPROOT_CONTROL_MAX_NODE_COUNT).
// safe to cast from usize to u8 // safe to cast from usize to u8
buf.push(leaf_info.merkle_branch.as_inner().len() as u8); buf.push(leaf_info.merkle_branch.as_inner().len() as u8);
buf.push(leaf_info.ver.as_u8()); buf.push(leaf_info.ver.into_consensus());
leaf_info.script.consensus_encode(&mut buf).expect("Vecs dont err"); leaf_info.script.consensus_encode(&mut buf).expect("Vecs dont err");
} }
buf buf
@ -305,7 +305,7 @@ impl Deserialize for TapTree {
bytes_iter.nth(consumed - 1); bytes_iter.nth(consumed - 1);
} }
let leaf_version = LeafVersion::from_u8(*version) let leaf_version = LeafVersion::from_consensus(*version)
.map_err(|_| encode::Error::ParseFailed("Leaf Version Error"))?; .map_err(|_| encode::Error::ParseFailed("Leaf Version Error"))?;
builder = builder.add_leaf_with_ver(usize::from(*depth), script, leaf_version) builder = builder.add_leaf_with_ver(usize::from(*depth), script, leaf_version)
.map_err(|_| encode::Error::ParseFailed("Tree not in DFS order"))?; .map_err(|_| encode::Error::ParseFailed("Tree not in DFS order"))?;

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@ -229,13 +229,13 @@ impl<'s> ScriptPath<'s> {
} }
/// Create a new ScriptPath structure using default leaf version value /// Create a new ScriptPath structure using default leaf version value
pub fn with_defaults(script: &'s Script) -> Self { pub fn with_defaults(script: &'s Script) -> Self {
Self::new(script, LeafVersion::default()) Self::new(script, LeafVersion::TapScript)
} }
/// Compute the leaf hash /// Compute the leaf hash
pub fn leaf_hash(&self) -> TapLeafHash { pub fn leaf_hash(&self) -> TapLeafHash {
let mut enc = TapLeafHash::engine(); let mut enc = TapLeafHash::engine();
self.leaf_version.as_u8().consensus_encode(&mut enc).expect("Writing to hash enging should never fail"); self.leaf_version.into_consensus().consensus_encode(&mut enc).expect("Writing to hash enging should never fail");
self.script.consensus_encode(&mut enc).expect("Writing to hash enging should never fail"); self.script.consensus_encode(&mut enc).expect("Writing to hash enging should never fail");
TapLeafHash::from_engine(enc) TapLeafHash::from_engine(enc)

View File

@ -15,6 +15,7 @@
//! //!
//! This module provides support for taproot tagged hashes. //! This module provides support for taproot tagged hashes.
//! //!
use prelude::*; use prelude::*;
use io; use io;
use secp256k1::{self, Secp256k1}; use secp256k1::{self, Secp256k1};
@ -120,7 +121,7 @@ impl TapLeafHash {
/// function to compute leaf hash from components /// function to compute leaf hash from components
pub fn from_script(script: &Script, ver: LeafVersion) -> TapLeafHash { pub fn from_script(script: &Script, ver: LeafVersion) -> TapLeafHash {
let mut eng = TapLeafHash::engine(); let mut eng = TapLeafHash::engine();
ver.as_u8() ver.into_consensus()
.consensus_encode(&mut eng) .consensus_encode(&mut eng)
.expect("engines don't error"); .expect("engines don't error");
script script
@ -142,6 +143,8 @@ pub const TAPROOT_LEAF_MASK: u8 = 0xfe;
/// Tapscript leaf version /// Tapscript leaf version
// https://github.com/bitcoin/bitcoin/blob/e826b22da252e0599c61d21c98ff89f366b3120f/src/script/interpreter.h#L226 // https://github.com/bitcoin/bitcoin/blob/e826b22da252e0599c61d21c98ff89f366b3120f/src/script/interpreter.h#L226
pub const TAPROOT_LEAF_TAPSCRIPT: u8 = 0xc0; pub const TAPROOT_LEAF_TAPSCRIPT: u8 = 0xc0;
/// Taproot annex prefix
pub const TAPROOT_ANNEX_PREFIX: u8 = 0x50;
/// Tapscript control base size /// Tapscript control base size
// https://github.com/bitcoin/bitcoin/blob/e826b22da252e0599c61d21c98ff89f366b3120f/src/script/interpreter.h#L227 // https://github.com/bitcoin/bitcoin/blob/e826b22da252e0599c61d21c98ff89f366b3120f/src/script/interpreter.h#L227
pub const TAPROOT_CONTROL_BASE_SIZE: usize = 33; pub const TAPROOT_CONTROL_BASE_SIZE: usize = 33;
@ -152,6 +155,7 @@ pub const TAPROOT_CONTROL_MAX_SIZE: usize =
// type alias for versioned tap script corresponding merkle proof // type alias for versioned tap script corresponding merkle proof
type ScriptMerkleProofMap = BTreeMap<(Script, LeafVersion), BTreeSet<TaprootMerkleBranch>>; type ScriptMerkleProofMap = BTreeMap<(Script, LeafVersion), BTreeSet<TaprootMerkleBranch>>;
/// Data structure for representing Taproot spending information. /// Data structure for representing Taproot spending information.
/// Taproot output corresponds to a combination of a /// Taproot output corresponds to a combination of a
/// single public key condition (known the internal key), and zero or more /// single public key condition (known the internal key), and zero or more
@ -216,7 +220,7 @@ impl TaprootSpendInfo {
{ {
let mut node_weights = BinaryHeap::<(Reverse<u64>, NodeInfo)>::new(); let mut node_weights = BinaryHeap::<(Reverse<u64>, NodeInfo)>::new();
for (p, leaf) in script_weights { for (p, leaf) in script_weights {
node_weights.push((Reverse(p as u64), NodeInfo::new_leaf_with_ver(leaf, LeafVersion::default()))); node_weights.push((Reverse(p as u64), NodeInfo::new_leaf_with_ver(leaf, LeafVersion::TapScript)));
} }
if node_weights.is_empty() { if node_weights.is_empty() {
return Err(TaprootBuilderError::IncompleteTree); return Err(TaprootBuilderError::IncompleteTree);
@ -409,7 +413,7 @@ impl TaprootBuilder {
/// See [`TaprootBuilder::add_leaf_with_ver`] for adding a leaf with specific version /// See [`TaprootBuilder::add_leaf_with_ver`] for adding a leaf with specific version
/// See [Wikipedia](https://en.wikipedia.org/wiki/Depth-first_search) for more details /// See [Wikipedia](https://en.wikipedia.org/wiki/Depth-first_search) for more details
pub fn add_leaf(self, depth: usize, script: Script) -> Result<Self, TaprootBuilderError> { pub fn add_leaf(self, depth: usize, script: Script) -> Result<Self, TaprootBuilderError> {
self.add_leaf_with_ver(depth, script, LeafVersion::default()) self.add_leaf_with_ver(depth, script, LeafVersion::TapScript)
} }
/// Add a hidden/omitted node at a depth `depth` to the builder. /// Add a hidden/omitted node at a depth `depth` to the builder.
@ -680,7 +684,7 @@ impl ControlBlock {
return Err(TaprootError::InvalidControlBlockSize(sl.len())); return Err(TaprootError::InvalidControlBlockSize(sl.len()));
} }
let output_key_parity = secp256k1::Parity::from((sl[0] & 1) as i32); let output_key_parity = secp256k1::Parity::from((sl[0] & 1) as i32);
let leaf_version = LeafVersion::from_u8(sl[0] & TAPROOT_LEAF_MASK)?; let leaf_version = LeafVersion::from_consensus(sl[0] & TAPROOT_LEAF_MASK)?;
let internal_key = UntweakedPublicKey::from_slice(&sl[1..TAPROOT_CONTROL_BASE_SIZE]) let internal_key = UntweakedPublicKey::from_slice(&sl[1..TAPROOT_CONTROL_BASE_SIZE])
.map_err(TaprootError::InvalidInternalKey)?; .map_err(TaprootError::InvalidInternalKey)?;
let merkle_branch = TaprootMerkleBranch::from_slice(&sl[TAPROOT_CONTROL_BASE_SIZE..])?; let merkle_branch = TaprootMerkleBranch::from_slice(&sl[TAPROOT_CONTROL_BASE_SIZE..])?;
@ -700,7 +704,7 @@ impl ControlBlock {
/// Serialize to a writer. Returns the number of bytes written /// Serialize to a writer. Returns the number of bytes written
pub fn encode<Write: io::Write>(&self, mut writer: Write) -> io::Result<usize> { pub fn encode<Write: io::Write>(&self, mut writer: Write) -> io::Result<usize> {
let first_byte: u8 = i32::from(self.output_key_parity) as u8 | self.leaf_version.as_u8(); let first_byte: u8 = i32::from(self.output_key_parity) as u8 | self.leaf_version.into_consensus();
let mut bytes_written = 0; let mut bytes_written = 0;
bytes_written += writer.write(&[first_byte])?; bytes_written += writer.write(&[first_byte])?;
bytes_written += writer.write(&self.internal_key.serialize())?; bytes_written += writer.write(&self.internal_key.serialize())?;
@ -759,16 +763,16 @@ impl ControlBlock {
/// The leaf version for tapleafs /// The leaf version for tapleafs
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)] #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))] #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
pub struct LeafVersion(u8); pub enum LeafVersion {
/// BIP-342 tapscript
TapScript,
impl Default for LeafVersion { /// Future leaf version
fn default() -> Self { Future(u8)
LeafVersion(TAPROOT_LEAF_TAPSCRIPT)
}
} }
impl LeafVersion { impl LeafVersion {
/// Obtain LeafVersion from u8, will error when last bit of ver is even or /// Obtain LeafVersion from u8, will error when last bit of ver is odd or
/// when ver is 0x50 (ANNEX_TAG) /// when ver is 0x50 (ANNEX_TAG)
// Text from BIP341: // Text from BIP341:
// In order to support some forms of static analysis that rely on // In order to support some forms of static analysis that rely on
@ -779,23 +783,32 @@ impl LeafVersion {
// or an opcode that is not valid as the first opcode). // or an opcode that is not valid as the first opcode).
// The values that comply to this rule are the 32 even values between // The values that comply to this rule are the 32 even values between
// 0xc0 and 0xfe and also 0x66, 0x7e, 0x80, 0x84, 0x96, 0x98, 0xba, 0xbc, 0xbe // 0xc0 and 0xfe and also 0x66, 0x7e, 0x80, 0x84, 0x96, 0x98, 0xba, 0xbc, 0xbe
pub fn from_u8(ver: u8) -> Result<Self, TaprootError> { pub fn from_consensus(version: u8) -> Result<Self, TaprootError> {
if ver & TAPROOT_LEAF_MASK == ver && ver != 0x50 { match version {
Ok(LeafVersion(ver)) TAPROOT_LEAF_TAPSCRIPT => Ok(LeafVersion::TapScript),
} else { TAPROOT_ANNEX_PREFIX => Err(TaprootError::InvalidTaprootLeafVersion(TAPROOT_ANNEX_PREFIX)),
Err(TaprootError::InvalidTaprootLeafVersion(ver)) odd if odd & TAPROOT_LEAF_MASK != odd => Err(TaprootError::InvalidTaprootLeafVersion(odd)),
future => Ok(LeafVersion::Future(future)),
} }
} }
/// Get the inner version from LeafVersion /// Get the inner version from LeafVersion
pub fn as_u8(&self) -> u8 { pub fn into_consensus(self) -> u8 {
self.0 match self {
LeafVersion::TapScript => TAPROOT_LEAF_TAPSCRIPT,
LeafVersion::Future(version) => version,
}
} }
} }
impl Into<u8> for LeafVersion { impl fmt::Display for LeafVersion {
fn into(self) -> u8 { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
self.0 match (self, f.alternate()) {
(LeafVersion::TapScript, false) => f.write_str("tapscript"),
(LeafVersion::TapScript, true) => fmt::Display::fmt(&TAPROOT_LEAF_TAPSCRIPT, f),
(LeafVersion::Future(version), false) => write!(f, "future_script_{:#02x}", version),
(LeafVersion::Future(version), true) => fmt::Display::fmt(version, f),
}
} }
} }
@ -1063,7 +1076,7 @@ mod test {
length, length,
tree_info tree_info
.script_map .script_map
.get(&(Script::from_hex(script).unwrap(), LeafVersion::default())) .get(&(Script::from_hex(script).unwrap(), LeafVersion::TapScript))
.expect("Present Key") .expect("Present Key")
.iter() .iter()
.next() .next()
@ -1078,7 +1091,7 @@ mod test {
// Try to create and verify a control block from each path // Try to create and verify a control block from each path
for (_weights, script) in script_weights { for (_weights, script) in script_weights {
let ver_script = (script, LeafVersion::default()); let ver_script = (script, LeafVersion::TapScript);
let ctrl_block = tree_info.control_block(&ver_script).unwrap(); let ctrl_block = tree_info.control_block(&ver_script).unwrap();
assert!(ctrl_block.verify_taproot_commitment(&secp, &output_key, &ver_script.0)) assert!(ctrl_block.verify_taproot_commitment(&secp, &output_key, &ver_script.0))
} }
@ -1114,7 +1127,7 @@ mod test {
let output_key = tree_info.output_key(); let output_key = tree_info.output_key();
for script in vec![a, b, c, d, e] { for script in vec![a, b, c, d, e] {
let ver_script = (script, LeafVersion::default()); let ver_script = (script, LeafVersion::TapScript);
let ctrl_block = tree_info.control_block(&ver_script).unwrap(); let ctrl_block = tree_info.control_block(&ver_script).unwrap();
assert!(ctrl_block.verify_taproot_commitment(&secp, &output_key, &ver_script.0)) assert!(ctrl_block.verify_taproot_commitment(&secp, &output_key, &ver_script.0))
} }
@ -1137,7 +1150,7 @@ mod test {
} }
} else { } else {
let script = Script::from_str(v["script"].as_str().unwrap()).unwrap(); let script = Script::from_str(v["script"].as_str().unwrap()).unwrap();
let ver = LeafVersion::from_u8(v["leafVersion"].as_u64().unwrap() as u8).unwrap(); let ver = LeafVersion::from_consensus(v["leafVersion"].as_u64().unwrap() as u8).unwrap();
leaves.push((script.clone(), ver)); leaves.push((script.clone(), ver));
builder = builder.add_leaf_with_ver(depth, script, ver).unwrap(); builder = builder.add_leaf_with_ver(depth, script, ver).unwrap();
} }