Struct Mmr 

pub struct Mmr<H: CHasher> { /* private fields */ }

Implementation of Mmr.

Max Capacity

The maximum number of elements that can be stored is usize::MAX (u32::MAX on 32-bit architectures).

Implementations

impl<H: CHasher> Mmr<H>

pub fn new() -> Self

Return a new (empty) Mmr.

pub fn init(config: Config<H>) -> Self

Return an Mmr initialized with the given config.

pub fn size(&self) -> u64

Return the total number of nodes in the MMR, irrespective of any pruning. The next added element’s position will have this value.

pub fn leaves(&self) -> u64

Return the total number of leaves in the MMR.

pub fn last_leaf_pos(&self) -> Option<u64>

Return the position of the last leaf in this MMR, or None if the MMR is empty.

pub fn pruned_to_pos(&self) -> u64

pub fn oldest_retained_pos(&self) -> Option<u64>

Return the position of the oldest retained node in the MMR, not including those cached in pinned_nodes.

pub fn get_node_unchecked(&self, pos: u64) -> &H::Digest

Returns the requested node, assuming it is either retained or known to exist in the pinned_nodes map.

pub fn get_node(&self, pos: u64) -> Option<H::Digest>

Returns the requested node or None if it is not stored in the MMR.

pub fn add(&mut self, hasher: &mut impl Hasher<H>, element: &[u8]) -> u64

Add element to the MMR and return its position in the MMR. The element can be an arbitrary byte slice, and need not be converted to a digest first.

Warning

Panics if there are unprocessed batch updates.

pub fn add_batched( &mut self, hasher: &mut impl Hasher<H>, element: &[u8], ) -> u64

Add element to the MMR and return its position in the MMR, but without updating ancestors until sync is called. The element can be an arbitrary byte slice, and need not be converted to a digest first.

pub fn pop(&mut self) -> Result<u64, Error>

Pop the most recent leaf element out of the MMR if it exists, returning Empty or ElementPruned errors otherwise.

Warning

Panics if there are unprocessed batch updates.

pub fn update_leaf( &mut self, hasher: &mut impl Hasher<H>, pos: u64, element: &[u8], )

Change the digest of any retained leaf. This is useful if you want to use the MMR implementation as an updatable binary Merkle tree, and otherwise should be avoided.

Warning

• Panics if pos does not correspond to a leaf, or if the leaf has been pruned.

• This method will change the root and invalidate any previous inclusion proofs.

• Use of this method will prevent using this structure as a base mmr for grafting.

pub fn update_leaf_batched<T: AsRef<[u8]> + Sync>( &mut self, hasher: &mut impl Hasher<H>, updates: &[(u64, T)], )

Batch update the digests of multiple retained leaves.

Warning

Panics if any of the updated leaves has been pruned.

pub fn is_dirty(&self) -> bool

Returns whether there are pending updates.

pub fn sync(&mut self, hasher: &mut impl Hasher<H>)

Process any pending batched updates.

pub fn root(&self, hasher: &mut impl Hasher<H>) -> H::Digest

Computes the root of the MMR.

Warning

Panics if there are unprocessed batch updates.

pub async fn proof(&self, element_pos: u64) -> Result<Proof<H::Digest>, Error>

Return an inclusion proof for the specified element. Returns ElementPruned error if some element needed to generate the proof has been pruned.

Warning

Panics if there are unprocessed batch updates.

pub async fn range_proof( &self, start_element_pos: u64, end_element_pos: u64, ) -> Result<Proof<H::Digest>, Error>

Return an inclusion proof for the specified range of elements, inclusive of both endpoints. Returns ElementPruned error if some element needed to generate the proof has been pruned.

Warning

Panics if there are unprocessed batch updates.

pub fn prune_all(&mut self)

Prune all nodes and pin the O(log2(n)) number of them required for proof generation going forward.

Warning

Panics if there are unprocessed batch updates.

pub fn prune_to_pos(&mut self, pos: u64)

Prune all nodes up to but not including the given position, and pin the O(log2(n)) number of them required for proof generation.

Warning

Panics if there are unprocessed batch updates.

pub fn clone_pruned(&self) -> Self

A lightweight cloning operation that “clones” only the fully pruned state of this MMR. The output is exactly the same as the result of mmr.prune_all(), only you get a copy without mutating the original, and the thread pool if any is not cloned.

Runtime is Log_2(n) in the number of elements even if the original MMR is never pruned.

Warning

Panics if there are unprocessed batch updates.

Trait Implementations

impl<H: CHasher> Builder<H> for Mmr<H>

async fn add( &mut self, hasher: &mut impl Hasher<H>, element: &[u8], ) -> Result<u64, Error>

Add element to the MMR and return its position within it. The element can be an arbitrary byte slice, and need not be converted to a digest first.

fn root(&self, hasher: &mut impl Hasher<H>) -> H::Digest

Return the root hash of the MMR.

impl<H: CHasher> Default for Mmr<H>

fn default() -> Self

Returns the “default value” for a type.

impl<H> Storage<<H as Hasher>::Digest> for Mmr<H>

where H: CHasher,

fn size(&self) -> u64

Return the number of elements in the MMR.

async fn get_node(&self, position: u64) -> Result<Option<H::Digest>, Error>

Return the specified node of the MMR if it exists & hasn’t been pruned.