openethereum/util/patricia_trie/src/fatdb.rs
Marek Kotewicz e95b093483 dissolve util (#7460)
* ethereum-types refactor in progress

* ethereum-types refactor in progress

* ethereum-types refactor in progress

* ethereum-types refactor in progress

* ethereum-types refactor finished

* removed obsolete util/src/lib.rs

* removed commented out code
2018-01-10 15:35:18 +03:00

121 lines
3.4 KiB
Rust

// Copyright 2015-2017 Parity Technologies (UK) Ltd.
// This file is part of Parity.
// Parity is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// Parity is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License
// along with Parity. If not, see <http://www.gnu.org/licenses/>.
use ethereum_types::H256;
use keccak::keccak;
use hashdb::HashDB;
use super::{TrieDB, Trie, TrieDBIterator, TrieItem, TrieIterator, Query};
/// A `Trie` implementation which hashes keys and uses a generic `HashDB` backing database.
/// Additionaly it stores inserted hash-key mappings for later retrieval.
///
/// Use it as a `Trie` or `TrieMut` trait object.
pub struct FatDB<'db> {
raw: TrieDB<'db>,
}
impl<'db> FatDB<'db> {
/// Create a new trie with the backing database `db` and empty `root`
/// Initialise to the state entailed by the genesis block.
/// This guarantees the trie is built correctly.
pub fn new(db: &'db HashDB, root: &'db H256) -> super::Result<Self> {
let fatdb = FatDB {
raw: TrieDB::new(db, root)?
};
Ok(fatdb)
}
/// Get the backing database.
pub fn db(&self) -> &HashDB {
self.raw.db()
}
}
impl<'db> Trie for FatDB<'db> {
fn iter<'a>(&'a self) -> super::Result<Box<TrieIterator<Item = TrieItem> + 'a>> {
FatDBIterator::new(&self.raw).map(|iter| Box::new(iter) as Box<_>)
}
fn root(&self) -> &H256 {
self.raw.root()
}
fn contains(&self, key: &[u8]) -> super::Result<bool> {
self.raw.contains(&keccak(key))
}
fn get_with<'a, 'key, Q: Query>(&'a self, key: &'key [u8], query: Q) -> super::Result<Option<Q::Item>>
where 'a: 'key
{
self.raw.get_with(&keccak(key), query)
}
}
/// Itarator over inserted pairs of key values.
pub struct FatDBIterator<'db> {
trie_iterator: TrieDBIterator<'db>,
trie: &'db TrieDB<'db>,
}
impl<'db> FatDBIterator<'db> {
/// Creates new iterator.
pub fn new(trie: &'db TrieDB) -> super::Result<Self> {
Ok(FatDBIterator {
trie_iterator: TrieDBIterator::new(trie)?,
trie: trie,
})
}
}
impl<'db> TrieIterator for FatDBIterator<'db> {
fn seek(&mut self, key: &[u8]) -> super::Result<()> {
self.trie_iterator.seek(&keccak(key))
}
}
impl<'db> Iterator for FatDBIterator<'db> {
type Item = TrieItem<'db>;
fn next(&mut self) -> Option<Self::Item> {
self.trie_iterator.next()
.map(|res|
res.map(|(hash, value)| {
let aux_hash = keccak(hash);
(self.trie.db().get(&aux_hash).expect("Missing fatdb hash").into_vec(), value)
})
)
}
}
#[test]
fn fatdb_to_trie() {
use memorydb::MemoryDB;
use hashdb::DBValue;
use super::fatdbmut::FatDBMut;
use super::TrieMut;
let mut memdb = MemoryDB::new();
let mut root = H256::default();
{
let mut t = FatDBMut::new(&mut memdb, &mut root);
t.insert(&[0x01u8, 0x23], &[0x01u8, 0x23]).unwrap();
}
let t = FatDB::new(&memdb, &root).unwrap();
assert_eq!(t.get(&[0x01u8, 0x23]).unwrap().unwrap(), DBValue::from_slice(&[0x01u8, 0x23]));
assert_eq!(t.iter().unwrap().map(Result::unwrap).collect::<Vec<_>>(), vec![(vec![0x01u8, 0x23], DBValue::from_slice(&[0x01u8, 0x23] as &[u8]))]);
}