openethereum/util/patricia_trie/src/sectriedb.rs

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// Copyright 2015-2017 Parity Technologies (UK) Ltd.
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// 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/>.
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use bigint::hash::H256;
use keccak::keccak;
use hashdb::HashDB;
use super::triedb::TrieDB;
use super::{Trie, TrieItem, TrieIterator, Query};
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/// A `Trie` implementation which hashes keys and uses a generic `HashDB` backing database.
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///
/// Use it as a `Trie` trait object. You can use `raw()` to get the backing `TrieDB` object.
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pub struct SecTrieDB<'db> {
raw: TrieDB<'db>
}
impl<'db> SecTrieDB<'db> {
/// Create a new trie with the backing database `db` and empty `root`
///
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/// Initialise to the state entailed by the genesis block.
/// This guarantees the trie is built correctly.
/// Returns an error if root does not exist.
pub fn new(db: &'db HashDB, root: &'db H256) -> super::Result<Self> {
Ok(SecTrieDB { raw: TrieDB::new(db, root)? })
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}
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/// Get a reference to the underlying raw `TrieDB` struct.
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pub fn raw(&self) -> &TrieDB {
&self.raw
}
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/// Get a mutable reference to the underlying raw `TrieDB` struct.
pub fn raw_mut(&mut self) -> &mut TrieDB<'db> {
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&mut self.raw
}
}
impl<'db> Trie for SecTrieDB<'db> {
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fn iter<'a>(&'a self) -> super::Result<Box<TrieIterator<Item = TrieItem> + 'a>> {
TrieDB::iter(&self.raw)
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}
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fn root(&self) -> &H256 { self.raw.root() }
fn contains(&self, key: &[u8]) -> super::Result<bool> {
self.raw.contains(&keccak(key))
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}
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)
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}
}
#[test]
fn trie_to_sectrie() {
use memorydb::MemoryDB;
use hashdb::DBValue;
use super::triedbmut::TrieDBMut;
use super::TrieMut;
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let mut memdb = MemoryDB::new();
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let mut root = H256::default();
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{
let mut t = TrieDBMut::new(&mut memdb, &mut root);
t.insert(&keccak(&[0x01u8, 0x23]), &[0x01u8, 0x23]).unwrap();
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}
let t = SecTrieDB::new(&memdb, &root).unwrap();
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assert_eq!(t.get(&[0x01u8, 0x23]).unwrap().unwrap(), DBValue::from_slice(&[0x01u8, 0x23]));
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}