Taproot descriptor #267
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| Original file line number | Diff line number | Diff line change |
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| @@ -0,0 +1,260 @@ | ||
| // Tapscript | ||
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| use super::checksum::{desc_checksum, verify_checksum}; | ||
| use bitcoin::hashes::_export::_core::fmt::Formatter; | ||
| use errstr; | ||
| use expression::{self, FromTree, Tree}; | ||
| use miniscript::{limits::TAPROOT_MAX_NODE_COUNT, Miniscript}; | ||
| use std::cmp::max; | ||
| use std::sync::Arc; | ||
| use std::{fmt, str::FromStr}; | ||
| use Segwitv0; | ||
| use {Error, MiniscriptKey}; | ||
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| #[derive(Clone, Ord, PartialOrd, Eq, PartialEq, Hash)] | ||
| pub enum TapTree<Pk: MiniscriptKey> { | ||
| Tree(Arc<TapTree<Pk>>, Arc<TapTree<Pk>>), | ||
| Leaf(Arc<Miniscript<Pk, Segwitv0>>), | ||
|
There was a problem hiding this comment. @sanket1729: I assume we can't use There was a problem hiding this comment. @dr-orlovsky. This is being done in #278 now |
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| } | ||
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| #[derive(Clone, Ord, PartialOrd, Eq, PartialEq, Hash)] | ||
| pub struct Tr<Pk: MiniscriptKey> { | ||
| internal_key: Pk, | ||
| tree: Option<TapTree<Pk>>, | ||
| } | ||
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| impl<Pk: MiniscriptKey> TapTree<Pk> { | ||
| fn taptree_height(&self) -> usize { | ||
| match *self { | ||
| TapTree::Tree(ref left_tree, ref right_tree) => { | ||
| 1 + max(left_tree.taptree_height(), right_tree.taptree_height()) | ||
| } | ||
| TapTree::Leaf(_) => 1, | ||
| } | ||
| } | ||
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| pub fn to_string_no_checksum(&self) -> String { | ||
| match self { | ||
| TapTree::Tree(ref left, ref right) => { | ||
| format!("{{{},{}}}", *left, *right) | ||
| } | ||
| TapTree::Leaf(ref script) => format!("{}", *script), | ||
| } | ||
| } | ||
| } | ||
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| impl<Pk: MiniscriptKey> fmt::Display for TapTree<Pk> { | ||
| fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result { | ||
| let desc = self.to_string_no_checksum(); | ||
| write!(f, "{}", &desc) | ||
| } | ||
| } | ||
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| impl<Pk: MiniscriptKey> Tr<Pk> { | ||
| pub fn new(internal_key: Pk, tree: Option<TapTree<Pk>>) -> Result<Self, Error> { | ||
| let nodes = match tree { | ||
| Some(ref t) => t.taptree_height(), | ||
| None => 0, | ||
| }; | ||
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| if nodes <= TAPROOT_MAX_NODE_COUNT { | ||
| Ok(Self { internal_key, tree }) | ||
|
There was a problem hiding this comment. If condition is reversed. It should be error if nodes > TAPROOT_MAX_NODE_COUNT |
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| } else { | ||
| Err(Error::MaxRecursiveDepthExceeded) | ||
| } | ||
| } | ||
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| fn to_string_no_checksum(&self) -> String { | ||
| let key = &self.internal_key; | ||
| match self.tree { | ||
| Some(ref s) => format!("tr({},{})", key, s), | ||
| None => format!("tr({})", key), | ||
| } | ||
| } | ||
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| pub fn internal_key(&self) -> &Pk { | ||
| &self.internal_key | ||
| } | ||
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| pub fn taptree(&self) -> &Option<TapTree<Pk>> { | ||
| &self.tree | ||
| } | ||
| } | ||
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| impl<Pk> Tr<Pk> | ||
| where | ||
| Pk: MiniscriptKey + FromStr, | ||
| Pk::Hash: FromStr, | ||
| <Pk as FromStr>::Err: ToString, | ||
| <<Pk as MiniscriptKey>::Hash as FromStr>::Err: ToString, | ||
| { | ||
|
There was a problem hiding this comment. Same comment about the bounds here. Try to separate out the functions that really need the bound into its own There was a problem hiding this comment. Also make accessor function for fields in |
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| pub fn tr_script_path(tree: &Tree) -> Result<TapTree<Pk>, Error> { | ||
| match tree { | ||
| Tree { name, args } if name.len() > 0 && args.len() == 0 => { | ||
| let script = Miniscript::<Pk, Segwitv0>::from_str(name)?; | ||
| Ok(TapTree::Leaf(Arc::new(script))) | ||
| } | ||
| Tree { name, args } if name.len() == 0 && args.len() == 2 => { | ||
| let left = Self::tr_script_path(&args[0])?; | ||
| let right = Self::tr_script_path(&args[1])?; | ||
| Ok(TapTree::Tree(Arc::new(left), Arc::new(right))) | ||
| } | ||
| _ => { | ||
| return Err(Error::Unexpected( | ||
| "unknown format for script spending paths while parsing taproot descriptor" | ||
| .to_string(), | ||
| )); | ||
| } | ||
| } | ||
| } | ||
| } | ||
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| impl<Pk: MiniscriptKey> FromTree for Tr<Pk> | ||
| where | ||
| Pk: MiniscriptKey + FromStr, | ||
| Pk::Hash: FromStr, | ||
| <Pk as FromStr>::Err: ToString, | ||
| <<Pk as MiniscriptKey>::Hash as FromStr>::Err: ToString, | ||
| { | ||
| fn from_tree(top: &Tree) -> Result<Self, Error> { | ||
| if top.name == "tr" { | ||
| match top.args.len() { | ||
| 1 => { | ||
| let key = &top.args[0]; | ||
| if key.args.len() > 0 { | ||
| return Err(Error::Unexpected(format!( | ||
| "#{} script associated with `key-path` while parsing taproot descriptor", | ||
| key.args.len() | ||
| ))); | ||
| } | ||
| Ok(Tr { | ||
| internal_key: expression::terminal(key, Pk::from_str)?, | ||
| tree: None, | ||
| }) | ||
| } | ||
| 2 => { | ||
| let ref key = top.args[0]; | ||
| if key.args.len() > 0 { | ||
| return Err(Error::Unexpected(format!( | ||
| "#{} script associated with `key-path` while parsing taproot descriptor", | ||
| key.args.len() | ||
| ))); | ||
| } | ||
| let ref tree = top.args[1]; | ||
| let ret = Tr::tr_script_path(tree)?; | ||
| Ok(Tr { | ||
| internal_key: expression::terminal(key, Pk::from_str)?, | ||
| tree: Some(ret), | ||
| }) | ||
| } | ||
| _ => { | ||
| return Err(Error::Unexpected(format!( | ||
| "{}[#{} args] while parsing taproot descriptor", | ||
| top.name, | ||
| top.args.len() | ||
| ))); | ||
| } | ||
| } | ||
| } else { | ||
| return Err(Error::Unexpected(format!( | ||
| "{}[#{} args] while parsing taproot descriptor", | ||
| top.name, | ||
| top.args.len() | ||
| ))); | ||
| } | ||
| } | ||
| } | ||
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| impl<Pk: MiniscriptKey> FromStr for Tr<Pk> | ||
| where | ||
| Pk: MiniscriptKey + FromStr, | ||
| Pk::Hash: FromStr, | ||
| <Pk as FromStr>::Err: ToString, | ||
| <<Pk as MiniscriptKey>::Hash as FromStr>::Err: ToString, | ||
| { | ||
| type Err = Error; | ||
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| fn from_str(s: &str) -> Result<Self, Self::Err> { | ||
| let desc_str = verify_checksum(s)?; | ||
| let top = parse_tr(desc_str)?; | ||
| Self::from_tree(&top) | ||
| } | ||
| } | ||
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| impl<Pk: MiniscriptKey> fmt::Display for Tr<Pk> { | ||
| fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { | ||
| let desc = self.to_string_no_checksum(); | ||
| let checksum = desc_checksum(&desc).map_err(|_| fmt::Error)?; | ||
| write!(f, "{}#{}", &desc, &checksum) | ||
| } | ||
| } | ||
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| fn parse_tr(s: &str) -> Result<Tree, Error> { | ||
| for ch in s.bytes() { | ||
| if ch > 0x7f { | ||
| return Err(Error::Unprintable(ch)); | ||
| } | ||
| } | ||
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| let ret = if s.len() > 3 && &s[..3] == "tr(" && s.as_bytes()[s.len() - 1] == b')' { | ||
| let rest = &s[3..s.len() - 1]; | ||
| if !rest.contains(',') { | ||
| let internal_key = Tree { | ||
| name: rest, | ||
| args: vec![], | ||
| }; | ||
| return Ok(Tree { | ||
| name: "tr", | ||
| args: vec![internal_key], | ||
| }); | ||
| } | ||
| // use str::split_once() method to refactor this when compiler version bumps up | ||
| let (key, script) = split_once(rest, ',') | ||
| .ok_or_else(|| Error::BadDescriptor("invalid taproot descriptor".to_string()))?; | ||
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| let internal_key = Tree { | ||
| name: key, | ||
| args: vec![], | ||
| }; | ||
| if script.is_empty() { | ||
| return Ok(Tree { | ||
| name: "tr", | ||
| args: vec![internal_key], | ||
| }); | ||
| } | ||
| let (tree, rest) = expression::Tree::from_slice_helper_curly(script, 1)?; | ||
| if rest.is_empty() { | ||
| Ok(Tree { | ||
| name: "tr", | ||
| args: vec![internal_key, tree], | ||
| }) | ||
| } else { | ||
| Err(errstr(rest)) | ||
| } | ||
| } else { | ||
| Err(Error::Unexpected("invalid taproot descriptor".to_string())) | ||
| }; | ||
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| return ret; | ||
| } | ||
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| fn split_once(inp: &str, delim: char) -> Option<(&str, &str)> { | ||
| let ret = if inp.len() == 0 { | ||
| None | ||
| } else { | ||
| let mut found = inp.len(); | ||
| for (idx, ch) in inp.chars().enumerate() { | ||
| if ch == delim { | ||
| found = idx; | ||
| break; | ||
| } | ||
| } | ||
| // No comma or trailing comma found | ||
| if found >= inp.len() - 1 { | ||
| Some((&inp[..], "")) | ||
| } else { | ||
| Some((&inp[..found], &inp[found + 1..])) | ||
|
There was a problem hiding this comment. Add a comment that this deals with the case when the |
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| } | ||
| }; | ||
| return ret; | ||
| } | ||
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In 73dd23e,
You should be exposing public utilities from private module tr to the external user. In particular, I think you need to expose
TapTree/Tr.A good exercise might be to write an example (see
/examplesfolder) to see how an external user might use the library.There was a problem hiding this comment.
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This is still not addressed
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We still need a statement with
pub use self::tr::{TapTree}and all other utilities that need to be exposed.