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Move-only: restructure merkle tree source for extraction.

This commit is contained in:
Kris Nuttycombe 2023-03-16 10:30:36 -06:00
parent 6f2cbfc7de
commit 667a7b841e
1 changed files with 71 additions and 77 deletions
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148
zcash_primitives/src/merkle_tree.rs
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@ -150,33 +150,6 @@ impl<Node, const DEPTH: u8> CommitmentTree<Node, DEPTH> {
}
}
/// Reads a `CommitmentTree` from its serialized form.
pub fn read_commitment_tree<Node: HashSer, R: Read, const DEPTH: u8>(
mut reader: R,
) -> io::Result<CommitmentTree<Node, DEPTH>> {
let left = Optional::read(&mut reader, Node::read)?;
let right = Optional::read(&mut reader, Node::read)?;
let parents = Vector::read(&mut reader, |r| Optional::read(r, Node::read))?;
Ok(CommitmentTree {
left,
right,
parents,
})
}
/// Serializes this tree as an array of bytes.
pub fn write_commitment_tree<Node: HashSer, W: Write, const DEPTH: u8>(
tree: &CommitmentTree<Node, DEPTH>,
mut writer: W,
) -> io::Result<()> {
Optional::write(&mut writer, tree.left.as_ref(), |w, n| n.write(w))?;
Optional::write(&mut writer, tree.right.as_ref(), |w, n| n.write(w))?;
Vector::write(&mut writer, &tree.parents, |w, e| {
Optional::write(w, e.as_ref(), |w, n| n.write(w))
})
}
impl<Node: Hashable + Clone, const DEPTH: u8> CommitmentTree<Node, DEPTH> {
/// Adds a leaf node to the tree.
///
@ -257,6 +230,33 @@ impl<Node: Hashable + Clone, const DEPTH: u8> CommitmentTree<Node, DEPTH> {
}
}
/// Reads a `CommitmentTree` from its serialized form.
pub fn read_commitment_tree<Node: HashSer, R: Read, const DEPTH: u8>(
mut reader: R,
) -> io::Result<CommitmentTree<Node, DEPTH>> {
let left = Optional::read(&mut reader, Node::read)?;
let right = Optional::read(&mut reader, Node::read)?;
let parents = Vector::read(&mut reader, |r| Optional::read(r, Node::read))?;
Ok(CommitmentTree {
left,
right,
parents,
})
}
/// Serializes this tree as an array of bytes.
pub fn write_commitment_tree<Node: HashSer, W: Write, const DEPTH: u8>(
tree: &CommitmentTree<Node, DEPTH>,
mut writer: W,
) -> io::Result<()> {
Optional::write(&mut writer, tree.left.as_ref(), |w, n| n.write(w))?;
Optional::write(&mut writer, tree.right.as_ref(), |w, n| n.write(w))?;
Vector::write(&mut writer, &tree.parents, |w, e| {
Optional::write(w, e.as_ref(), |w, n| n.write(w))
})
}
/// An updatable witness to a path from a position in a particular [`CommitmentTree`].
///
/// Appending the same commitments in the same order to both the original
@ -304,62 +304,12 @@ impl<Node, const DEPTH: u8> IncrementalWitness<Node, DEPTH> {
cursor: None,
}
}
}
/// Reads an `IncrementalWitness` from its serialized form.
#[allow(clippy::redundant_closure)]
pub fn read_incremental_witness<Node: HashSer, R: Read, const DEPTH: u8>(
mut reader: R,
) -> io::Result<IncrementalWitness<Node, DEPTH>> {
let tree = read_commitment_tree(&mut reader)?;
let filled = Vector::read(&mut reader, |r| Node::read(r))?;
let cursor = Optional::read(&mut reader, read_commitment_tree)?;
let mut witness = IncrementalWitness {
tree,
filled,
cursor_depth: 0,
cursor,
};
witness.cursor_depth = witness.next_depth();
Ok(witness)
}
/// Serializes this `IncrementalWitness` as an array of bytes.
pub fn write_incremental_witness<Node: HashSer, W: Write, const DEPTH: u8>(
witness: &IncrementalWitness<Node, DEPTH>,
mut writer: W,
) -> io::Result<()> {
write_commitment_tree(&witness.tree, &mut writer)?;
Vector::write(&mut writer, &witness.filled, |w, n| n.write(w))?;
Optional::write(&mut writer, witness.cursor.as_ref(), |w, t| {
write_commitment_tree(t, w)
})
}
impl<Node, const DEPTH: u8> IncrementalWitness<Node, DEPTH> {
/// Returns the position of the witnessed leaf node in the commitment tree.
pub fn position(&self) -> usize {
self.tree.size() - 1
}
}
impl<Node: Hashable + Clone, const DEPTH: u8> IncrementalWitness<Node, DEPTH> {
fn filler(&self) -> PathFiller<Node> {
let cursor_root = self
.cursor
.as_ref()
.map(|c| c.root_inner(self.cursor_depth, PathFiller::empty()));
PathFiller {
queue: self.filled.iter().cloned().chain(cursor_root).collect(),
}
}
}
impl<Node, const DEPTH: u8> IncrementalWitness<Node, DEPTH> {
/// Finds the next "depth" of an unfilled subtree.
fn next_depth(&self) -> u8 {
let mut skip: u8 = self
@ -401,6 +351,17 @@ impl<Node, const DEPTH: u8> IncrementalWitness<Node, DEPTH> {
}
impl<Node: Hashable + Clone, const DEPTH: u8> IncrementalWitness<Node, DEPTH> {
fn filler(&self) -> PathFiller<Node> {
let cursor_root = self
.cursor
.as_ref()
.map(|c| c.root_inner(self.cursor_depth, PathFiller::empty()));
PathFiller {
queue: self.filled.iter().cloned().chain(cursor_root).collect(),
}
}
/// Tracks a leaf node that has been added to the underlying tree.
///
/// Returns an error if the tree is full.
@ -482,6 +443,39 @@ impl<Node: Hashable + Clone, const DEPTH: u8> IncrementalWitness<Node, DEPTH> {
}
}
/// Reads an `IncrementalWitness` from its serialized form.
#[allow(clippy::redundant_closure)]
pub fn read_incremental_witness<Node: HashSer, R: Read, const DEPTH: u8>(
mut reader: R,
) -> io::Result<IncrementalWitness<Node, DEPTH>> {
let tree = read_commitment_tree(&mut reader)?;
let filled = Vector::read(&mut reader, |r| Node::read(r))?;
let cursor = Optional::read(&mut reader, read_commitment_tree)?;
let mut witness = IncrementalWitness {
tree,
filled,
cursor_depth: 0,
cursor,
};
witness.cursor_depth = witness.next_depth();
Ok(witness)
}
/// Serializes this `IncrementalWitness` as an array of bytes.
pub fn write_incremental_witness<Node: HashSer, W: Write, const DEPTH: u8>(
witness: &IncrementalWitness<Node, DEPTH>,
mut writer: W,
) -> io::Result<()> {
write_commitment_tree(&witness.tree, &mut writer)?;
Vector::write(&mut writer, &witness.filled, |w, n| n.write(w))?;
Optional::write(&mut writer, witness.cursor.as_ref(), |w, t| {
write_commitment_tree(t, w)
})
}
/// A path from a position in a particular commitment tree to the root of that tree.
#[derive(Clone, Debug, PartialEq, Eq)]
pub struct MerklePath<Node, const DEPTH: u8> {