Merge rust-bitcoin/rust-bitcoin#2619: Call is_witness_program from witness_version

dec05b63e9 Refactor witness_version and is_witness_program (Tobin C. Harding)
dac552b436 Add unit tests for shortest/longest witness program (Tobin C. Harding)

Pull request description:

  Refactor `witness_version` and `is_witness_program`.

  - Patch 2 adds a couple of preparatory unit tests.
  - Patch 2 does the refactor

  Fix: #2618

ACKs for top commit:
  apoelstra:
    ACK dec05b63e9
  sanket1729:
    ACK dec05b63e9

Tree-SHA512: 3db0a1d8175cbb2fd18f3254854d02db3ad7efa2620b12f08d9727ef6bb5854f0a015917e57023cd2196a36d13276e80536a0e96318c44a1173da4f6793ca370
This commit is contained in:
Andrew Poelstra 2024-03-22 21:45:08 +00:00
commit 1656e1a09a
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1 changed files with 56 additions and 18 deletions

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@ -165,9 +165,35 @@ impl Script {
}
/// Returns witness version of the script, if any, assuming the script is a `scriptPubkey`.
///
/// # Returns
///
/// The witness version if this script is found to conform to the SegWit rules:
///
/// > A scriptPubKey (or redeemScript as defined in BIP16/P2SH) that consists of a 1-byte
/// > push opcode (for 0 to 16) followed by a data push between 2 and 40 bytes gets a new
/// > special meaning. The value of the first push is called the "version byte". The following
/// > byte vector pushed is called the "witness program".
#[inline]
pub fn witness_version(&self) -> Option<WitnessVersion> {
self.0.first().and_then(|opcode| WitnessVersion::try_from(Opcode::from(*opcode)).ok())
let script_len = self.0.len();
if !(4..=42).contains(&script_len) {
return None;
}
let ver_opcode = Opcode::from(self.0[0]); // Version 0 or PUSHNUM_1-PUSHNUM_16
let push_opbyte = self.0[1]; // Second byte push opcode 2-40 bytes
if push_opbyte < OP_PUSHBYTES_2.to_u8() || push_opbyte > OP_PUSHBYTES_40.to_u8()
{
return None;
}
// Check that the rest of the script has the correct size
if script_len - 2 != push_opbyte as usize {
return None;
}
WitnessVersion::try_from(ver_opcode).ok()
}
/// Checks whether a script pubkey is a P2SH output.
@ -293,23 +319,7 @@ impl Script {
/// Checks whether a script pubkey is a Segregated Witness (segwit) program.
#[inline]
pub fn is_witness_program(&self) -> bool {
// A scriptPubKey (or redeemScript as defined in BIP16/P2SH) that consists of a 1-byte
// push opcode (for 0 to 16) followed by a data push between 2 and 40 bytes gets a new
// special meaning. The value of the first push is called the "version byte". The following
// byte vector pushed is called the "witness program".
let script_len = self.0.len();
if !(4..=42).contains(&script_len) {
return false;
}
let ver_opcode = Opcode::from(self.0[0]); // Version 0 or PUSHNUM_1-PUSHNUM_16
let push_opbyte = self.0[1]; // Second byte push opcode 2-40 bytes
WitnessVersion::try_from(ver_opcode).is_ok()
&& push_opbyte >= OP_PUSHBYTES_2.to_u8()
&& push_opbyte <= OP_PUSHBYTES_40.to_u8()
// Check that the rest of the script has the correct size
&& script_len - 2 == push_opbyte as usize
}
pub fn is_witness_program(&self) -> bool { self.witness_version().is_some() }
/// Checks whether a script pubkey is a P2WSH output.
#[inline]
@ -660,3 +670,31 @@ delegate_index!(
RangeToInclusive<usize>,
(Bound<usize>, Bound<usize>)
);
#[cfg(test)]
mod tests {
use super::*;
use crate::blockdata::script::witness_program::WitnessProgram;
#[test]
fn shortest_witness_program() {
let bytes = [0x00; 2]; // Arbitrary bytes, witprog must be between 2 and 40.
let version = WitnessVersion::V15; // Arbitrary version number, intentionally not 0 or 1.
let p = WitnessProgram::new(version, &bytes).expect("failed to create witness program");
let script = ScriptBuf::new_witness_program(&p);
assert_eq!(script.witness_version(), Some(version));
}
#[test]
fn longest_witness_program() {
let bytes = [0x00; 40]; // Arbitrary bytes, witprog must be between 2 and 40.
let version = WitnessVersion::V16; // Arbitrary version number, intentionally not 0 or 1.
let p = WitnessProgram::new(version, &bytes).expect("failed to create witness program");
let script = ScriptBuf::new_witness_program(&p);
assert_eq!(script.witness_version(), Some(version));
}
}