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incrementalmerkletree
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Expose operations on `legacy-api` types required for serialization & testing.

This commit is contained in:
Kris Nuttycombe 2023-03-16 11:53:48 -06:00
parent 7cb2bdcc8f
commit 71557cc0e3
2 changed files with 129 additions and 80 deletions
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144
incrementalmerkletree/src/frontier.rs
View File

@ -248,19 +248,23 @@ impl<H: Hashable + Clone, const DEPTH: u8> Frontier<H, DEPTH> {
}
#[cfg(feature = "legacy-api")]
pub(crate) struct PathFiller<H> {
pub(crate) queue: VecDeque<H>,
pub struct PathFiller<H> {
queue: VecDeque<H>,
}
#[cfg(feature = "legacy-api")]
impl<H: Hashable> PathFiller<H> {
pub(crate) fn empty() -> Self {
pub fn empty() -> Self {
PathFiller {
queue: VecDeque::new(),
}
}
pub(crate) fn next(&mut self, level: Level) -> H {
pub fn new(queue: VecDeque<H>) -> Self {
Self { queue }
}
pub fn next(&mut self, level: Level) -> H {
self.queue
.pop_front()
.unwrap_or_else(|| H::empty_root(level))
@ -287,63 +291,32 @@ impl<H, const DEPTH: u8> CommitmentTree<H, DEPTH> {
}
}
pub fn from_frontier(frontier: &Frontier<H, DEPTH>) -> Self
where
H: Clone,
{
frontier.value().map_or_else(Self::empty, |f| {
let mut ommers_iter = f.ommers().iter().cloned();
let (left, right) = if f.position().is_odd() {
(
ommers_iter
.next()
.expect("An ommer must exist if the frontier position is odd"),
Some(f.leaf().clone()),
)
} else {
(f.leaf().clone(), None)
};
let upos: usize = f.position().into();
Self {
left: Some(left),
pub fn from_parts(
left: Option<H>,
right: Option<H>,
parents: Vec<Option<H>>,
) -> Result<Self, ()> {
if parents.len() < usize::from(DEPTH) {
Ok(CommitmentTree {
left,
right,
parents: (1u8..DEPTH)
.into_iter()
.map(|i| {
if upos & (1 << i) == 0 {
None
} else {
ommers_iter.next()
}
})
.collect(),
}
})
parents,
})
} else {
Err(())
}
}
pub fn to_frontier(&self) -> Frontier<H, DEPTH>
where
H: Hashable + Clone,
{
if self.size() == 0 {
Frontier::empty()
} else {
let ommers_iter = self.parents.iter().filter_map(|v| v.as_ref()).cloned();
let (leaf, ommers) = match (self.left.as_ref(), self.right.as_ref()) {
(Some(a), None) => (a.clone(), ommers_iter.collect()),
(Some(a), Some(b)) => (
b.clone(),
Some(a.clone()).into_iter().chain(ommers_iter).collect(),
),
_ => unreachable!(),
};
pub fn left(&self) -> &Option<H> {
&self.left
}
// If a frontier cannot be successfully constructed from the
// parts of a commitment tree, it is a programming error.
Frontier::from_parts((self.size() - 1).into(), leaf, ommers)
.expect("Frontier should be constructable from CommitmentTree.")
}
pub fn right(&self) -> &Option<H> {
&self.right
}
pub fn parents(&self) -> &Vec<Option<H>> {
&self.parents
}
/// Returns the number of leaf nodes in the tree.
@ -381,6 +354,59 @@ impl<H, const DEPTH: u8> CommitmentTree<H, DEPTH> {
#[cfg(feature = "legacy-api")]
impl<H: Hashable + Clone, const DEPTH: u8> CommitmentTree<H, DEPTH> {
pub fn from_frontier(frontier: &Frontier<H, DEPTH>) -> Self {
frontier.value().map_or_else(Self::empty, |f| {
let mut ommers_iter = f.ommers().iter().cloned();
let (left, right) = if f.position().is_odd() {
(
ommers_iter
.next()
.expect("An ommer must exist if the frontier position is odd"),
Some(f.leaf().clone()),
)
} else {
(f.leaf().clone(), None)
};
let upos: usize = f.position().into();
Self {
left: Some(left),
right,
parents: (1u8..DEPTH)
.into_iter()
.map(|i| {
if upos & (1 << i) == 0 {
None
} else {
ommers_iter.next()
}
})
.collect(),
}
})
}
pub fn to_frontier(&self) -> Frontier<H, DEPTH> {
if self.size() == 0 {
Frontier::empty()
} else {
let ommers_iter = self.parents.iter().filter_map(|v| v.as_ref()).cloned();
let (leaf, ommers) = match (self.left.as_ref(), self.right.as_ref()) {
(Some(a), None) => (a.clone(), ommers_iter.collect()),
(Some(a), Some(b)) => (
b.clone(),
Some(a.clone()).into_iter().chain(ommers_iter).collect(),
),
_ => unreachable!(),
};
// If a frontier cannot be successfully constructed from the
// parts of a commitment tree, it is a programming error.
Frontier::from_parts((self.size() - 1).into(), leaf, ommers)
.expect("Frontier should be constructable from CommitmentTree.")
}
}
/// Adds a leaf node to the tree.
///
/// Returns an error if the tree is full.
@ -422,10 +448,10 @@ impl<H: Hashable + Clone, const DEPTH: u8> CommitmentTree<H, DEPTH> {
/// Returns the current root of the tree.
pub fn root(&self) -> H {
self.root_inner(DEPTH, PathFiller::empty())
self.root_at_depth(DEPTH, PathFiller::empty())
}
pub(crate) fn root_inner(&self, depth: u8, mut filler: PathFiller<H>) -> H {
pub fn root_at_depth(&self, depth: u8, mut filler: PathFiller<H>) -> H {
assert!(depth > 0);
// 1) Hash left and right leaves together.

65
incrementalmerkletree/src/witness.rs
View File

@ -14,16 +14,8 @@ pub struct MerklePath<H, const DEPTH: u8> {
}
impl<H, const DEPTH: u8> MerklePath<H, DEPTH> {
pub fn auth_path(&self) -> &[(H, bool)] {
&self.auth_path
}
pub fn position(&self) -> u64 {
self.position
}
/// Constructs a Merkle path directly from a path and position.
pub fn from_path(auth_path: Vec<(H, bool)>, position: u64) -> Result<Self, ()> {
pub fn from_parts(auth_path: Vec<(H, bool)>, position: u64) -> Result<Self, ()> {
if auth_path.len() == usize::from(DEPTH) {
Ok(MerklePath {
auth_path,
@ -33,6 +25,14 @@ impl<H, const DEPTH: u8> MerklePath<H, DEPTH> {
Err(())
}
}
pub fn auth_path(&self) -> &[(H, bool)] {
&self.auth_path
}
pub fn position(&self) -> u64 {
self.position
}
}
impl<H: Hashable, const DEPTH: u8> MerklePath<H, DEPTH> {
@ -91,7 +91,7 @@ pub struct IncrementalWitness<H, const DEPTH: u8> {
impl<H, const DEPTH: u8> IncrementalWitness<H, DEPTH> {
/// Creates an `IncrementalWitness` for the most recent commitment added to the given
/// [`CommitmentTree`].
pub fn from_tree(tree: CommitmentTree<H, DEPTH>) -> IncrementalWitness<H, DEPTH> {
pub fn from_tree(tree: CommitmentTree<H, DEPTH>) -> Self {
IncrementalWitness {
tree,
filled: vec![],
@ -100,6 +100,35 @@ impl<H, const DEPTH: u8> IncrementalWitness<H, DEPTH> {
}
}
pub fn from_parts(
tree: CommitmentTree<H, DEPTH>,
filled: Vec<H>,
cursor: Option<CommitmentTree<H, DEPTH>>,
) -> Self {
let mut witness = IncrementalWitness {
tree,
filled,
cursor_depth: 0,
cursor,
};
witness.cursor_depth = witness.next_depth();
witness
}
pub fn tree(&self) -> &CommitmentTree<H, DEPTH> {
&self.tree
}
pub fn filled(&self) -> &Vec<H> {
&self.filled
}
pub fn cursor(&self) -> &Option<CommitmentTree<H, DEPTH>> {
&self.cursor
}
/// Returns the position of the witnessed leaf node in the commitment tree.
pub fn position(&self) -> usize {
self.tree.size() - 1
@ -150,11 +179,9 @@ impl<H: Hashable + Clone, const DEPTH: u8> IncrementalWitness<H, DEPTH> {
let cursor_root = self
.cursor
.as_ref()
.map(|c| c.root_inner(self.cursor_depth, PathFiller::empty()));
.map(|c| c.root_at_depth(self.cursor_depth, PathFiller::empty()));
PathFiller {
queue: self.filled.iter().cloned().chain(cursor_root).collect(),
}
PathFiller::new(self.filled.iter().cloned().chain(cursor_root).collect())
}
/// Tracks a leaf node that has been added to the underlying tree.
@ -166,7 +193,7 @@ impl<H: Hashable + Clone, const DEPTH: u8> IncrementalWitness<H, DEPTH> {
cursor.append(node).expect("cursor should not be full");
if cursor.is_complete(self.cursor_depth) {
self.filled
.push(cursor.root_inner(self.cursor_depth, PathFiller::empty()));
.push(cursor.root_at_depth(self.cursor_depth, PathFiller::empty()));
} else {
self.cursor = Some(cursor);
}
@ -191,11 +218,7 @@ impl<H: Hashable + Clone, const DEPTH: u8> IncrementalWitness<H, DEPTH> {
/// Returns the current root of the tree corresponding to the witness.
pub fn root(&self) -> H {
self.root_inner(DEPTH)
}
fn root_inner(&self, depth: u8) -> H {
self.tree.root_inner(depth, self.filler())
self.tree.root_at_depth(DEPTH, self.filler())
}
/// Returns the current witness, or None if the tree is empty.
@ -234,6 +257,6 @@ impl<H: Hashable + Clone, const DEPTH: u8> IncrementalWitness<H, DEPTH> {
assert_eq!(auth_path.len(), usize::from(depth));
MerklePath::from_path(auth_path, self.position() as u64).ok()
MerklePath::from_parts(auth_path, self.position() as u64).ok()
}
}