// 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 .
//! DB backend wrapper for Account trie
use std::collections::HashMap;
use hash::{KECCAK_NULL_RLP, keccak};
use ethereum_types::H256;
use kvdb::DBValue;
use hashdb::HashDB;
use rlp::NULL_RLP;
#[cfg(test)]
use ethereum_types::Address;
// combines a key with an address hash to ensure uniqueness.
// leaves the first 96 bits untouched in order to support partial key lookup.
#[inline]
fn combine_key<'a>(address_hash: &'a H256, key: &'a H256) -> H256 {
let mut dst = key.clone();
{
let last_src: &[u8] = &*address_hash;
let last_dst: &mut [u8] = &mut *dst;
for (k, a) in last_dst[12..].iter_mut().zip(&last_src[12..]) {
*k ^= *a
}
}
dst
}
/// A factory for different kinds of account dbs.
#[derive(Debug, Clone)]
pub enum Factory {
/// Mangle hashes based on address.
Mangled,
/// Don't mangle hashes.
Plain,
}
impl Default for Factory {
fn default() -> Self { Factory::Mangled }
}
impl Factory {
/// Create a read-only accountdb.
/// This will panic when write operations are called.
pub fn readonly<'db>(&self, db: &'db HashDB, address_hash: H256) -> Box {
match *self {
Factory::Mangled => Box::new(AccountDB::from_hash(db, address_hash)),
Factory::Plain => Box::new(Wrapping(db)),
}
}
/// Create a new mutable hashdb.
pub fn create<'db>(&self, db: &'db mut HashDB, address_hash: H256) -> Box {
match *self {
Factory::Mangled => Box::new(AccountDBMut::from_hash(db, address_hash)),
Factory::Plain => Box::new(WrappingMut(db)),
}
}
}
// TODO: introduce HashDBMut?
/// DB backend wrapper for Account trie
/// Transforms trie node keys for the database
pub struct AccountDB<'db> {
db: &'db HashDB,
address_hash: H256,
}
impl<'db> AccountDB<'db> {
/// Create a new AccountDB from an address.
#[cfg(test)]
pub fn new(db: &'db HashDB, address: &Address) -> Self {
Self::from_hash(db, keccak(address))
}
/// Create a new AcountDB from an address' hash.
pub fn from_hash(db: &'db HashDB, address_hash: H256) -> Self {
AccountDB {
db: db,
address_hash: address_hash,
}
}
}
impl<'db> HashDB for AccountDB<'db>{
fn keys(&self) -> HashMap {
unimplemented!()
}
fn get(&self, key: &H256) -> Option {
if key == &KECCAK_NULL_RLP {
return Some(DBValue::from_slice(&NULL_RLP));
}
self.db.get(&combine_key(&self.address_hash, key))
}
fn contains(&self, key: &H256) -> bool {
if key == &KECCAK_NULL_RLP {
return true;
}
self.db.contains(&combine_key(&self.address_hash, key))
}
fn insert(&mut self, _value: &[u8]) -> H256 {
unimplemented!()
}
fn emplace(&mut self, _key: H256, _value: DBValue) {
unimplemented!()
}
fn remove(&mut self, _key: &H256) {
unimplemented!()
}
}
/// DB backend wrapper for Account trie
pub struct AccountDBMut<'db> {
db: &'db mut HashDB,
address_hash: H256,
}
impl<'db> AccountDBMut<'db> {
/// Create a new AccountDB from an address.
#[cfg(test)]
pub fn new(db: &'db mut HashDB, address: &Address) -> Self {
Self::from_hash(db, keccak(address))
}
/// Create a new AcountDB from an address' hash.
pub fn from_hash(db: &'db mut HashDB, address_hash: H256) -> Self {
AccountDBMut {
db: db,
address_hash: address_hash,
}
}
#[cfg(test)]
pub fn immutable(&'db self) -> AccountDB<'db> {
AccountDB { db: self.db, address_hash: self.address_hash.clone() }
}
}
impl<'db> HashDB for AccountDBMut<'db>{
fn keys(&self) -> HashMap {
unimplemented!()
}
fn get(&self, key: &H256) -> Option {
if key == &KECCAK_NULL_RLP {
return Some(DBValue::from_slice(&NULL_RLP));
}
self.db.get(&combine_key(&self.address_hash, key))
}
fn contains(&self, key: &H256) -> bool {
if key == &KECCAK_NULL_RLP {
return true;
}
self.db.contains(&combine_key(&self.address_hash, key))
}
fn insert(&mut self, value: &[u8]) -> H256 {
if value == &NULL_RLP {
return KECCAK_NULL_RLP.clone();
}
let k = keccak(value);
let ak = combine_key(&self.address_hash, &k);
self.db.emplace(ak, DBValue::from_slice(value));
k
}
fn emplace(&mut self, key: H256, value: DBValue) {
if key == KECCAK_NULL_RLP {
return;
}
let key = combine_key(&self.address_hash, &key);
self.db.emplace(key, value)
}
fn remove(&mut self, key: &H256) {
if key == &KECCAK_NULL_RLP {
return;
}
let key = combine_key(&self.address_hash, key);
self.db.remove(&key)
}
}
struct Wrapping<'db>(&'db HashDB);
impl<'db> HashDB for Wrapping<'db> {
fn keys(&self) -> HashMap {
unimplemented!()
}
fn get(&self, key: &H256) -> Option {
if key == &KECCAK_NULL_RLP {
return Some(DBValue::from_slice(&NULL_RLP));
}
self.0.get(key)
}
fn contains(&self, key: &H256) -> bool {
if key == &KECCAK_NULL_RLP {
return true;
}
self.0.contains(key)
}
fn insert(&mut self, _value: &[u8]) -> H256 {
unimplemented!()
}
fn emplace(&mut self, _key: H256, _value: DBValue) {
unimplemented!()
}
fn remove(&mut self, _key: &H256) {
unimplemented!()
}
}
struct WrappingMut<'db>(&'db mut HashDB);
impl<'db> HashDB for WrappingMut<'db>{
fn keys(&self) -> HashMap {
unimplemented!()
}
fn get(&self, key: &H256) -> Option {
if key == &KECCAK_NULL_RLP {
return Some(DBValue::from_slice(&NULL_RLP));
}
self.0.get(key)
}
fn contains(&self, key: &H256) -> bool {
if key == &KECCAK_NULL_RLP {
return true;
}
self.0.contains(key)
}
fn insert(&mut self, value: &[u8]) -> H256 {
if value == &NULL_RLP {
return KECCAK_NULL_RLP.clone();
}
self.0.insert(value)
}
fn emplace(&mut self, key: H256, value: DBValue) {
if key == KECCAK_NULL_RLP {
return;
}
self.0.emplace(key, value)
}
fn remove(&mut self, key: &H256) {
if key == &KECCAK_NULL_RLP {
return;
}
self.0.remove(key)
}
}