Struct patricia_trie::triedb::TrieDB

pub struct TrieDB<'db, H, C> where
    H: Hasher + 'db,
    C: NodeCodec<H>,  { /* fields omitted */ }

A Trie implementation using a generic HashDB backing database, a Hasher implementation to generate keys and a NodeCodec implementation to encode/decode the nodes.

Use it as a Trie trait object. You can use db() to get the backing database object. Use get and contains to query values associated with keys in the trie.

Example

extern crate patricia_trie as trie;
extern crate patricia_trie_ethereum as ethtrie;
extern crate hashdb;
extern crate keccak_hasher;
extern crate memorydb;
extern crate ethereum_types;

use trie::*;
use hashdb::*;
use keccak_hasher::KeccakHasher;
use memorydb::*;
use ethereum_types::H256;
use ethtrie::{TrieDB, TrieDBMut};


fn main() {
  let mut memdb = MemoryDB::<KeccakHasher>::new();
  let mut root = H256::new();
  TrieDBMut::new(&mut memdb, &mut root).insert(b"foo", b"bar").unwrap();
  let t = TrieDB::new(&memdb, &root).unwrap();
  assert!(t.contains(b"foo").unwrap());
  assert_eq!(t.get(b"foo").unwrap().unwrap(), DBValue::from_slice(b"bar"));
}

Methods

impl<'db, H, C> TrieDB<'db, H, C> where     H: Hasher,     C: NodeCodec<H>,

pub fn new(     db: &'db HashDB<H>,     root: &'db H::Out ) -> Result<Self, H::Out, C::Error>

Create a new trie with the backing database db and root Returns an error if root does not exist

pub fn db(&'db self) -> &'db HashDB<H>

Get the backing database.

Trait Implementations

impl<'db, H, C> Trie<H, C> for TrieDB<'db, H, C> where     H: Hasher,     C: NodeCodec<H>,

fn root(&self) -> &H::Out

Return the root of the trie.

fn get_with<'a, 'key, Q: Query<H>>(     &'a self,     key: &'key [u8],     query: Q ) -> Result<Option<Q::Item>, H::Out, C::Error> where     'a: 'key,

Search for the key with the given query parameter. See the docs of the Query trait for more details.

fn iter<'a>(     &'a self ) -> Result<Box<TrieIterator<H, C, Item = TrieItem<H::Out, C::Error>> + 'a>, H::Out, C::Error>

Returns a depth-first iterator over the elements of trie.

fn is_empty(&self) -> bool

Is the trie empty?

fn contains(&self, key: &[u8]) -> Result<bool, H::Out, C::Error>

Does the trie contain a given key?

fn get<'a, 'key>(     &'a self,     key: &'key [u8] ) -> Result<Option<DBValue>, H::Out, C::Error> where     'a: 'key,

What is the value of the given key in this trie?

impl<'db, H, C> Debug for TrieDB<'db, H, C> where     H: Hasher,     C: NodeCodec<H>,

fn fmt(&self, f: &mut Formatter) -> Result

Formats the value using the given formatter.