Crate shardtree

source ·
Expand description

shardtree is a space-efficient fixed-depth Merkle tree structure that is densely filled from the left. It supports:

  • Out-of-order insertion: leaves and nodes may be inserted into the tree in arbitrary order. The structure will keep track of the right-most filled position as the frontier of the tree; any unfilled leaves to the left of this position are considered “missing”, while any unfilled leaves to the right of this position are considered “empty”.
  • Witnessing: Individual leaves of the Merkle tree may be marked such that witnesses will be maintained for the marked leaves as additional nodes are inserted into the tree, but leaf and node data not specifically required to maintain these witnesses is not retained, for space efficiency.
  • Checkpointing: the tree may be reset to a previously checkpointed state, up to a fixed number of checkpoints.

Due to its structure (described in the store module), witnesses for marked leaves can be advanced up to recent checkpoints or the latest state of the tree, without having to insert each intermediate leaf individually. Instead, only the roots of all complete shards between the one containing the marked leaf and the tree frontier need to be inserted, along with the necessary nodes to build a path from the marked leaf to the root of the shard containing it.

Modules§

Structs§

  • BatchInsertionResult
    A type for the result of a batch insertion operation.
  • IncompleteAt
    A data structure describing the nature of a Node::Nil node in the tree that was introduced as the consequence of an insertion.
  • LocatedTree
    A binary Merkle tree with its root at the given address.
  • RetentionFlags
    Flags storing the Retention state of a leaf.
  • ShardTree
    A sparse binary Merkle tree of the specified depth, represented as an ordered collection of subtrees (shards) of a given maximum height.
  • Tree
    An immutable binary tree with each of its nodes tagged with an annotation value.

Enums§

  • Node
    A “pattern functor” for a single layer of a binary tree.

Type Aliases§