This is a go implementation of Merkle Patricia Tree (MPT) similar to that used in go-Ethereum. The reason for re-implementing it is to ease the adoption in other projects, as the MPT in go-Ethereum is coupled with other Ethereum modules and its interface is not clean.

For the detailed explanation of MPT, please refer to Ethereum wiki.

The usage of this library is simple.

MPT uses a key-value store as backend to store the tree nodes. Therefore, a key-value store instance is required before creating an MPT instance.

This library provides two implementaion of key-value store in ./kvstore

1. MemKVStore: essentially a go map which stores key-value pairs in memory
2. LevelDB: Google leveldb that persist key-value pairs in disk

//Creating a MemKVStore instance
memKv := kvstore.NewMemKVStore()

//Creating a LevelDB instance
leveldb, err := kvstore.NewLevelDB("path/to/leveldb/file")

// Creating an empty MPT
tree := mpt.New(nil, leveldb)

// Create an MPT from existing tree node
tree := mpt.New(node, leveldb)

// Creating an MPT from a known root hash
tree := mpt.New(mpt.HashNode(root_hash), leveldb)

Now you are good to go!

// Put and get
tree.Put([]byte("A"), []byte("a"))
tree.Get([]byte("A"))

Any put operation won't be persisted in key-value store backend until you call:

tree.Commit()

If you want to cancel all the operations until last commit:

tree.Abort()

// serialize the mpt
data, err := tree.Serialize()

// deserialze the mpt
tree := mpt.New(nil, leveldb)
tree.Deserialize(data)