parity-common/patricia_trie/src/sectriedbmut.rs

111 lines
3.3 KiB
Rust

// Copyright 2015-2018 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 hashdb::{HashDB, Hasher};
use super::{Result, DBValue, TrieMut, TrieDBMut};
use node_codec::NodeCodec;
/// A mutable `Trie` implementation which hashes keys and uses a generic `HashDB` backing database.
///
/// Use it as a `Trie` or `TrieMut` trait object. You can use `raw()` to get the backing `TrieDBMut` object.
pub struct SecTrieDBMut<'db, H, C>
where
H: Hasher + 'db,
C: NodeCodec<H>
{
raw: TrieDBMut<'db, H, C>
}
impl<'db, H, C> SecTrieDBMut<'db, H, C>
where
H: Hasher,
C: NodeCodec<H>
{
/// 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 mut HashDB<H, DBValue>, root: &'db mut H::Out) -> Self {
SecTrieDBMut { raw: TrieDBMut::new(db, root) }
}
/// Create a new trie with the backing database `db` and `root`.
///
/// Returns an error if root does not exist.
pub fn from_existing(db: &'db mut HashDB<H, DBValue>, root: &'db mut H::Out) -> Result<Self, H::Out, C::Error> {
Ok(SecTrieDBMut { raw: TrieDBMut::from_existing(db, root)? })
}
/// Get the backing database.
pub fn db(&self) -> &HashDB<H, DBValue> { self.raw.db() }
/// Get the backing database.
pub fn db_mut(&mut self) -> &mut HashDB<H, DBValue> { self.raw.db_mut() }
}
impl<'db, H, C> TrieMut<H, C> for SecTrieDBMut<'db, H, C>
where
H: Hasher,
C: NodeCodec<H>
{
fn root(&mut self) -> &H::Out {
self.raw.root()
}
fn is_empty(&self) -> bool {
self.raw.is_empty()
}
fn contains(&self, key: &[u8]) -> Result<bool, H::Out, C::Error> {
self.raw.contains(&H::hash(key).as_ref())
}
fn get<'a, 'key>(&'a self, key: &'key [u8]) -> Result<Option<DBValue>, H::Out, C::Error>
where 'a: 'key
{
self.raw.get(&H::hash(key).as_ref())
}
fn insert(&mut self, key: &[u8], value: &[u8]) -> Result<Option<DBValue>, H::Out, C::Error> {
self.raw.insert(&H::hash(key).as_ref(), value)
}
fn remove(&mut self, key: &[u8]) -> Result<Option<DBValue>, H::Out, C::Error> {
self.raw.remove(&H::hash(key).as_ref())
}
}
#[cfg(test)]
mod test {
use memorydb::MemoryDB;
use keccak;
use keccak_hasher::KeccakHasher;
use ethtrie::{TrieDB, SecTrieDBMut, trie::{Trie, TrieMut}};
use ethereum_types::H256;
use DBValue;
#[test]
fn sectrie_to_trie() {
let mut memdb = MemoryDB::<KeccakHasher, DBValue>::new();
let mut root = H256::new();
{
let mut t = SecTrieDBMut::new(&mut memdb, &mut root);
t.insert(&[0x01u8, 0x23], &[0x01u8, 0x23]).unwrap();
}
let t = TrieDB::new(&memdb, &root).unwrap();
assert_eq!(t.get(&keccak::keccak(&[0x01u8, 0x23])).unwrap().unwrap(), DBValue::from_slice(&[0x01u8, 0x23]));
}
}