Implement TryFrom for WitnessVersion

We have a bunch of 'from' methods that are fallible; `TryFrom` became
available in Rust 1.34 so we can use it now we have bumped our MSRV.

Implement the various `WitnessVersion` from methods using `TryFrom` and
deprecate the originals.
This commit is contained in:
Tobin C. Harding 2022-05-25 16:35:34 +10:00
parent b645b6b4b5
commit 632a5db8d9
2 changed files with 113 additions and 39 deletions

View File

@ -27,6 +27,7 @@ use crate::consensus::encode::MAX_VEC_SIZE;
use crate::prelude::*; use crate::prelude::*;
use crate::io; use crate::io;
use core::convert::TryFrom;
use core::{fmt, default::Default}; use core::{fmt, default::Default};
use core::ops::Index; use core::ops::Index;
@ -498,7 +499,7 @@ impl Script {
/// Returns witness version of the script, if any, assuming the script is a `scriptPubkey`. /// Returns witness version of the script, if any, assuming the script is a `scriptPubkey`.
#[inline] #[inline]
pub fn witness_version(&self) -> Option<WitnessVersion> { pub fn witness_version(&self) -> Option<WitnessVersion> {
self.0.get(0).and_then(|opcode| WitnessVersion::from_opcode(opcodes::All::from(*opcode)).ok()) self.0.get(0).and_then(|opcode| WitnessVersion::try_from(opcodes::All::from(*opcode)).ok())
} }
/// Checks whether a script pubkey is a P2SH output. /// Checks whether a script pubkey is a P2SH output.
@ -550,7 +551,7 @@ impl Script {
} }
let ver_opcode = opcodes::All::from(self.0[0]); // Version 0 or PUSHNUM_1-PUSHNUM_16 let ver_opcode = opcodes::All::from(self.0[0]); // Version 0 or PUSHNUM_1-PUSHNUM_16
let push_opbyte = self.0[1]; // Second byte push opcode 2-40 bytes let push_opbyte = self.0[1]; // Second byte push opcode 2-40 bytes
WitnessVersion::from_opcode(ver_opcode).is_ok() WitnessVersion::try_from(ver_opcode).is_ok()
&& push_opbyte >= opcodes::all::OP_PUSHBYTES_2.to_u8() && push_opbyte >= opcodes::all::OP_PUSHBYTES_2.to_u8()
&& push_opbyte <= opcodes::all::OP_PUSHBYTES_40.to_u8() && push_opbyte <= opcodes::all::OP_PUSHBYTES_40.to_u8()
// Check that the rest of the script has the correct size // Check that the rest of the script has the correct size

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@ -34,6 +34,7 @@
use crate::prelude::*; use crate::prelude::*;
use core::convert::TryFrom;
use core::fmt; use core::fmt;
use core::num::ParseIntError; use core::num::ParseIntError;
use core::str::FromStr; use core::str::FromStr;
@ -243,8 +244,8 @@ impl FromStr for WitnessVersion {
type Err = Error; type Err = Error;
fn from_str(s: &str) -> Result<Self, Self::Err> { fn from_str(s: &str) -> Result<Self, Self::Err> {
let version = s.parse().map_err(Error::UnparsableWitnessVersion)?; let version: u8 = s.parse().map_err(Error::UnparsableWitnessVersion)?;
WitnessVersion::from_num(version) WitnessVersion::try_from(version)
} }
} }
@ -258,8 +259,9 @@ impl WitnessVersion {
/// # Errors /// # Errors
/// If the integer does not correspond to any witness version, errors with /// If the integer does not correspond to any witness version, errors with
/// [`Error::InvalidWitnessVersion`]. /// [`Error::InvalidWitnessVersion`].
#[deprecated(since = "0.29.0", note = "use try_from instead")]
pub fn from_u5(value: ::bech32::u5) -> Result<Self, Error> { pub fn from_u5(value: ::bech32::u5) -> Result<Self, Error> {
WitnessVersion::from_num(value.to_u8()) Self::try_from(value)
} }
/// Converts an 8-bit unsigned integer value into [`WitnessVersion`] variant. /// Converts an 8-bit unsigned integer value into [`WitnessVersion`] variant.
@ -270,27 +272,9 @@ impl WitnessVersion {
/// # Errors /// # Errors
/// If the integer does not correspond to any witness version, errors with /// If the integer does not correspond to any witness version, errors with
/// [`Error::InvalidWitnessVersion`]. /// [`Error::InvalidWitnessVersion`].
#[deprecated(since = "0.29.0", note = "use try_from instead")]
pub fn from_num(no: u8) -> Result<Self, Error> { pub fn from_num(no: u8) -> Result<Self, Error> {
Ok(match no { Self::try_from(no)
0 => WitnessVersion::V0,
1 => WitnessVersion::V1,
2 => WitnessVersion::V2,
3 => WitnessVersion::V3,
4 => WitnessVersion::V4,
5 => WitnessVersion::V5,
6 => WitnessVersion::V6,
7 => WitnessVersion::V7,
8 => WitnessVersion::V8,
9 => WitnessVersion::V9,
10 => WitnessVersion::V10,
11 => WitnessVersion::V11,
12 => WitnessVersion::V12,
13 => WitnessVersion::V13,
14 => WitnessVersion::V14,
15 => WitnessVersion::V15,
16 => WitnessVersion::V16,
wrong => return Err(Error::InvalidWitnessVersion(wrong)),
})
} }
/// Converts bitcoin script opcode into [`WitnessVersion`] variant. /// Converts bitcoin script opcode into [`WitnessVersion`] variant.
@ -301,13 +285,9 @@ impl WitnessVersion {
/// # Errors /// # Errors
/// If the opcode does not correspond to any witness version, errors with /// If the opcode does not correspond to any witness version, errors with
/// [`Error::MalformedWitnessVersion`]. /// [`Error::MalformedWitnessVersion`].
#[deprecated(since = "0.29.0", note = "use try_from instead")]
pub fn from_opcode(opcode: opcodes::All) -> Result<Self, Error> { pub fn from_opcode(opcode: opcodes::All) -> Result<Self, Error> {
match opcode.to_u8() { Self::try_from(opcode)
0 => Ok(WitnessVersion::V0),
version if version >= opcodes::all::OP_PUSHNUM_1.to_u8() && version <= opcodes::all::OP_PUSHNUM_16.to_u8() =>
WitnessVersion::from_num(version - opcodes::all::OP_PUSHNUM_1.to_u8() + 1),
_ => Err(Error::MalformedWitnessVersion)
}
} }
/// Converts bitcoin script [`Instruction`] (parsed opcode) into [`WitnessVersion`] variant. /// Converts bitcoin script [`Instruction`] (parsed opcode) into [`WitnessVersion`] variant.
@ -319,12 +299,9 @@ impl WitnessVersion {
/// # Errors /// # Errors
/// If the opcode does not correspond to any witness version, errors with /// If the opcode does not correspond to any witness version, errors with
/// [`Error::MalformedWitnessVersion`] for the rest of opcodes. /// [`Error::MalformedWitnessVersion`] for the rest of opcodes.
#[deprecated(since = "0.29.0", note = "use try_from instead")]
pub fn from_instruction(instruction: Instruction) -> Result<Self, Error> { pub fn from_instruction(instruction: Instruction) -> Result<Self, Error> {
match instruction { Self::try_from(instruction)
Instruction::Op(op) => WitnessVersion::from_opcode(op),
Instruction::PushBytes(bytes) if bytes.is_empty() => Ok(WitnessVersion::V0),
Instruction::PushBytes(_) => Err(Error::MalformedWitnessVersion),
}
} }
/// Returns integer version number representation for a given [`WitnessVersion`] value. /// Returns integer version number representation for a given [`WitnessVersion`] value.
@ -355,6 +332,102 @@ impl WitnessVersion {
} }
} }
impl TryFrom<bech32::u5> for WitnessVersion {
type Error = Error;
/// Converts 5-bit unsigned integer value matching single symbol from Bech32(m) address encoding
/// ([`bech32::u5`]) into [`WitnessVersion`] variant.
///
/// # Returns
/// Version of the Witness program.
///
/// # Errors
/// If the integer does not correspond to any witness version, errors with
/// [`Error::InvalidWitnessVersion`].
fn try_from(value: bech32::u5) -> Result<Self, Self::Error> {
Self::try_from(value.to_u8())
}
}
impl TryFrom<u8> for WitnessVersion {
type Error = Error;
/// Converts an 8-bit unsigned integer value into [`WitnessVersion`] variant.
///
/// # Returns
/// Version of the Witness program.
///
/// # Errors
/// If the integer does not correspond to any witness version, errors with
/// [`Error::InvalidWitnessVersion`].
fn try_from(no: u8) -> Result<Self, Self::Error> {
use WitnessVersion::*;
Ok(match no {
0 => V0,
1 => V1,
2 => V2,
3 => V3,
4 => V4,
5 => V5,
6 => V6,
7 => V7,
8 => V8,
9 => V9,
10 => V10,
11 => V11,
12 => V12,
13 => V13,
14 => V14,
15 => V15,
16 => V16,
wrong => return Err(Error::InvalidWitnessVersion(wrong)),
})
}
}
impl TryFrom<opcodes::All> for WitnessVersion {
type Error = Error;
/// Converts bitcoin script opcode into [`WitnessVersion`] variant.
///
/// # Returns
/// Version of the Witness program (for opcodes in range of `OP_0`..`OP_16`).
///
/// # Errors
/// If the opcode does not correspond to any witness version, errors with
/// [`Error::MalformedWitnessVersion`].
fn try_from(opcode: opcodes::All) -> Result<Self, Self::Error> {
match opcode.to_u8() {
0 => Ok(WitnessVersion::V0),
version if version >= opcodes::all::OP_PUSHNUM_1.to_u8() && version <= opcodes::all::OP_PUSHNUM_16.to_u8() =>
WitnessVersion::try_from(version - opcodes::all::OP_PUSHNUM_1.to_u8() + 1),
_ => Err(Error::MalformedWitnessVersion)
}
}
}
impl<'a> TryFrom<Instruction<'a>> for WitnessVersion {
type Error = Error;
/// Converts bitcoin script [`Instruction`] (parsed opcode) into [`WitnessVersion`] variant.
///
/// # Returns
/// Version of the Witness program for [`Instruction::Op`] and [`Instruction::PushBytes`] with
/// byte value within `1..=16` range.
///
/// # Errors
/// If the opcode does not correspond to any witness version, errors with
/// [`Error::MalformedWitnessVersion`] for the rest of opcodes.
fn try_from(instruction: Instruction) -> Result<Self, Self::Error> {
match instruction {
Instruction::Op(op) => WitnessVersion::try_from(op),
Instruction::PushBytes(bytes) if bytes.is_empty() => Ok(WitnessVersion::V0),
Instruction::PushBytes(_) => Err(Error::MalformedWitnessVersion),
}
}
}
impl From<WitnessVersion> for ::bech32::u5 { impl From<WitnessVersion> for ::bech32::u5 {
/// Converts [`WitnessVersion`] instance into corresponding Bech32(m) u5-value ([`bech32::u5`]). /// Converts [`WitnessVersion`] instance into corresponding Bech32(m) u5-value ([`bech32::u5`]).
fn from(version: WitnessVersion) -> Self { fn from(version: WitnessVersion) -> Self {
@ -405,7 +478,7 @@ impl Payload {
} }
Payload::WitnessProgram { Payload::WitnessProgram {
version: WitnessVersion::from_opcode(opcodes::All::from(script[0]))?, version: WitnessVersion::try_from(opcodes::All::from(script[0]))?,
program: script[2..].to_vec(), program: script[2..].to_vec(),
} }
} else { } else {
@ -856,7 +929,7 @@ impl FromStr for Address {
// Get the script version and program (converted from 5-bit to 8-bit) // Get the script version and program (converted from 5-bit to 8-bit)
let (version, program): (WitnessVersion, Vec<u8>) = { let (version, program): (WitnessVersion, Vec<u8>) = {
let (v, p5) = payload.split_at(1); let (v, p5) = payload.split_at(1);
(WitnessVersion::from_u5(v[0])?, bech32::FromBase32::from_base32(p5)?) (WitnessVersion::try_from(v[0])?, bech32::FromBase32::from_base32(p5)?)
}; };
if program.len() < 2 || program.len() > 40 { if program.len() < 2 || program.len() > 40 {
@ -1277,7 +1350,7 @@ mod tests {
]; ];
let segwit_payload = (0..=16).map(|version| { let segwit_payload = (0..=16).map(|version| {
Payload::WitnessProgram { Payload::WitnessProgram {
version: WitnessVersion::from_num(version).unwrap(), version: WitnessVersion::try_from(version).unwrap(),
program: vec![] program: vec![]
} }
}).collect::<Vec<_>>(); }).collect::<Vec<_>>();