Exonum MerkleDB is a persistent storage implementation based on RocksDB which provides APIs to work with merkelized data structures.
Entry is a specific index that stores only one value. Useful for global
values, such as configuration. Similar to a combination of Box and
Option.ListIndex is a list of items stored in a sequential order. Similar to
Vec.SparseListIndex is a list of items stored in a sequential order. Similar
to ListIndex, but may contain indices without elements.MapIndex is a map of keys and values. Similar to BTreeMap.ProofListIndex is a Merkelized version of ListIndex that supports
cryptographic proofs of existence and is implemented as a Merkle tree.ProofMapIndex is a Merkelized version of MapIndex that supports cryptographic
proofs of existence and is implemented as a binary Merkle Patricia tree.KeySetIndex and ValueSetIndex are sets of items, similar to BTreeSet and
HashSet accordingly.Include exonum-merkledb as a dependency in your Cargo.toml:
```toml [dependencies] exonum-merkledb = "0.12.0"
```
If you need only to read the data you can create Snapshot. Objects
created from Snapshot provide a read-only access to the storage data.
To modify data you need to create an object based on Fork.
Fork and Snapshot can be obtained from the Database object.
Currently only one database backend is supported - RockDB.
```rust use std::path::Path; use exonum_merkledb::{ProofListIndex, Database, ListProof, DbOptions, RocksDB};
let dboptions = DbOptions::default(); let db = RocksDB::open(&Path::new("db"), &dboptions).unwrap(); let list_name = "list";
// Read-only list let snapshot = db.snapshot(); let list: ProofListIndex<_, u8> = ProofListIndex::new(list_name, &snapshot);
// Mutable list let fork = db.fork(); let mut list: ProofListIndex<_, u8> = ProofListIndex::new(list_name, &fork);
```
After adding elements to the object you can obtain cryptographic proofs for their existence or absence.
```rust list.push(1);
asserteq!(ListProof::Leaf(1), list.getproof(0));
if let ListProof::Absent(proof) = list.getproof(1) { println!("Element with index 1 is absent") }
```
exonum-merkledb is licensed under the Apache License (Version 2.0).
See LICENSE for details.