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account_db.rs 10.33 KiB
// Copyright 2018-2019 Parity Technologies (UK) Ltd.
// This file is part of Substrate.
// Substrate 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.
// Substrate 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 Substrate. If not, see <http://www.gnu.org/licenses/>.
//! Auxilliaries to help with managing partial changes to accounts state.
use super::{
AliveContractInfo, BalanceOf, CodeHash, ContractInfo, ContractInfoOf, Trait, TrieId,
TrieIdGenerator, prefixed_trie_id,
};
use crate::exec::StorageKey;
use rstd::cell::RefCell;
use rstd::collections::btree_map::{BTreeMap, Entry};
use rstd::prelude::*;
use runtime_io::blake2_256;
use runtime_primitives::traits::{Bounded, Zero};
use srml_support::traits::{Currency, Get, Imbalance, SignedImbalance, UpdateBalanceOutcome};
use srml_support::{storage::child, StorageMap};
use system;
// Note: we don't provide Option<Contract> because we can't create
// the trie_id in the overlay, thus we provide an overlay on the fields
// specifically.
pub struct ChangeEntry<T: Trait> {
balance: Option<BalanceOf<T>>,
/// If None, the code_hash remains untouched.
code_hash: Option<CodeHash<T>>,
rent_allowance: Option<BalanceOf<T>>,
storage: BTreeMap<StorageKey, Option<Vec<u8>>>,
}
// Cannot derive(Default) since it erroneously bounds T by Default.
impl<T: Trait> Default for ChangeEntry<T> {
fn default() -> Self {
ChangeEntry {
rent_allowance: Default::default(),
balance: Default::default(),
code_hash: Default::default(),
storage: Default::default(),
}
}
}
pub type ChangeSet<T> = BTreeMap<<T as system::Trait>::AccountId, ChangeEntry<T>>;
pub trait AccountDb<T: Trait> {
/// Account is used when overlayed otherwise trie_id must be provided.
/// This is for performance reason.
///
/// Trie id is None iff account doesn't have an associated trie id in <ContractInfoOf<T>>.
/// Because DirectAccountDb bypass the lookup for this association.
fn get_storage(&self, account: &T::AccountId, trie_id: Option<&TrieId>, location: &StorageKey) -> Option<Vec<u8>>;
/// If account has an alive contract then return the code hash associated.
fn get_code_hash(&self, account: &T::AccountId) -> Option<CodeHash<T>>;
/// If account has an alive contract then return the rent allowance associated.
fn get_rent_allowance(&self, account: &T::AccountId) -> Option<BalanceOf<T>>;
/// Returns false iff account has no alive contract nor tombstone.
fn contract_exists(&self, account: &T::AccountId) -> bool;
fn get_balance(&self, account: &T::AccountId) -> BalanceOf<T>;
fn commit(&mut self, change_set: ChangeSet<T>);
}
pub struct DirectAccountDb;
impl<T: Trait> AccountDb<T> for DirectAccountDb {
fn get_storage(
&self,
_account: &T::AccountId,
trie_id: Option<&TrieId>,
location: &StorageKey,
) -> Option<Vec<u8>> {
// see issue FIXME #2744 to stop querying child trie
trie_id.and_then(|id| {
child::child_trie(&prefixed_trie_id(&id)[..])
.and_then(|child_trie| child::get_raw(child_trie.node_ref(), &blake2_256(location))
)})
}
fn get_code_hash(&self, account: &T::AccountId) -> Option<CodeHash<T>> {
<ContractInfoOf<T>>::get(account).and_then(|i| i.as_alive().map(|i| i.code_hash))
}
fn get_rent_allowance(&self, account: &T::AccountId) -> Option<BalanceOf<T>> {
<ContractInfoOf<T>>::get(account).and_then(|i| i.as_alive().map(|i| i.rent_allowance))
}
fn contract_exists(&self, account: &T::AccountId) -> bool {
<ContractInfoOf<T>>::exists(account)
}
fn get_balance(&self, account: &T::AccountId) -> BalanceOf<T> {
T::Currency::free_balance(account)
}
fn commit(&mut self, s: ChangeSet<T>) {
let mut total_imbalance = SignedImbalance::zero();
for (address, changed) in s.into_iter() {
if let Some(balance) = changed.balance {
let (imbalance, outcome) = T::Currency::make_free_balance_be(&address, balance);
total_imbalance = total_imbalance.merge(imbalance);
if let UpdateBalanceOutcome::AccountKilled = outcome {
// Account killed. This will ultimately lead to calling `OnFreeBalanceZero` callback
// which will make removal of CodeHashOf and AccountStorage for this account.
// In order to avoid writing over the deleted properties we `continue` here.
continue;
}
}
if changed.code_hash.is_some()
|| changed.rent_allowance.is_some()
|| !changed.storage.is_empty()
{
let old_info = match <ContractInfoOf<T>>::get(&address) {
Some(ContractInfo::Alive(alive)) => Some(alive),
None => None,
// Cannot commit changes to tombstone contract
Some(ContractInfo::Tombstone(_)) => continue,
};
let block_number = <system::Module<T>>::block_number();
let mut new_info = if let Some(info) = old_info.clone() {
info
} else if let Some(code_hash) = changed.code_hash {
AliveContractInfo::<T> {
code_hash,
storage_size: T::StorageSizeOffset::get(),
trie_id: <T as Trait>::TrieIdGenerator::trie_id(&address),
deduct_block: block_number,
rent_allowance: <BalanceOf<T>>::max_value(),
last_write: None,
}
} else {
// No contract exist and no code_hash provided
continue;
};
if let Some(rent_allowance) = changed.rent_allowance {
new_info.rent_allowance = rent_allowance;
}
if let Some(code_hash) = changed.code_hash {
new_info.code_hash = code_hash;
}
let p_key = prefixed_trie_id(&new_info.trie_id);
// see issue FIXME #2744 to avoid this fetch
let child_trie = child::fetch_or_new(p_key.as_ref());
if !changed.storage.is_empty() {
new_info.last_write = Some(block_number);
}
for (k, v) in changed.storage.into_iter() {
if let Some(value) = child::get_raw(child_trie.node_ref(), &blake2_256(&k)) {
new_info.storage_size -= value.len() as u32;
}
if let Some(value) = v {
new_info.storage_size += value.len() as u32;
child::put_raw(&child_trie, &blake2_256(&k), &value[..]);
} else {
child::kill(&child_trie, &blake2_256(&k));
}
}
if old_info
.map(|old_info| old_info != new_info)
.unwrap_or(true)
{
<ContractInfoOf<T>>::insert(&address, ContractInfo::Alive(new_info));
}
}
}
match total_imbalance {
// If we've detected a positive imbalance as a result of our contract-level machinations
// then it's indicative of a buggy contracts system.
// Panicking is far from ideal as it opens up a DoS attack on block validators, however
// it's a less bad option than allowing arbitrary value to be created.
SignedImbalance::Positive(ref p) if !p.peek().is_zero() =>
panic!("contract subsystem resulting in positive imbalance!"),
_ => {}
}
}
}
pub struct OverlayAccountDb<'a, T: Trait + 'a> {
local: RefCell<ChangeSet<T>>,
underlying: &'a dyn AccountDb<T>,
}
impl<'a, T: Trait> OverlayAccountDb<'a, T> {
pub fn new(underlying: &'a dyn AccountDb<T>) -> OverlayAccountDb<'a, T> {
OverlayAccountDb {
local: RefCell::new(ChangeSet::new()),
underlying,
}
}
pub fn into_change_set(self) -> ChangeSet<T> {
self.local.into_inner()
}
pub fn set_storage(
&mut self,
account: &T::AccountId,
location: StorageKey,
value: Option<Vec<u8>>,
) {
self.local.borrow_mut()
.entry(account.clone())
.or_insert(Default::default())
.storage
.insert(location, value);
}
/// Return an error if contract already exists (either if it is alive or tombstone)
pub fn create_contract(
&mut self,
account: &T::AccountId,
code_hash: CodeHash<T>,
) -> Result<(), &'static str> {
if self.contract_exists(account) {
return Err("Alive contract or tombstone already exists");
}
let mut local = self.local.borrow_mut();
let contract = local.entry(account.clone()).or_insert_with(|| Default::default());
contract.code_hash = Some(code_hash);
contract.rent_allowance = Some(<BalanceOf<T>>::max_value());
Ok(())
}
/// Assume contract exists
pub fn set_rent_allowance(&mut self, account: &T::AccountId, rent_allowance: BalanceOf<T>) {
self.local
.borrow_mut()
.entry(account.clone())
.or_insert(Default::default())
.rent_allowance = Some(rent_allowance);
}
pub fn set_balance(&mut self, account: &T::AccountId, balance: BalanceOf<T>) {
self.local
.borrow_mut()
.entry(account.clone())
.or_insert(Default::default())
.balance = Some(balance);
}
}
impl<'a, T: Trait> AccountDb<T> for OverlayAccountDb<'a, T> {
fn get_storage(
&self,
account: &T::AccountId,
trie_id: Option<&TrieId>,
location: &StorageKey
) -> Option<Vec<u8>> {
self.local
.borrow()
.get(account)
.and_then(|a| a.storage.get(location))
.cloned()
.unwrap_or_else(|| self.underlying.get_storage(account, trie_id, location))
}
fn get_code_hash(&self, account: &T::AccountId) -> Option<CodeHash<T>> {
self.local
.borrow()
.get(account)
.and_then(|changes| changes.code_hash)
.or_else(|| self.underlying.get_code_hash(account))
}
fn get_rent_allowance(&self, account: &T::AccountId) -> Option<BalanceOf<T>> {
self.local
.borrow()
.get(account)
.and_then(|changes| changes.rent_allowance)
.or_else(|| self.underlying.get_rent_allowance(account))
}
fn contract_exists(&self, account: &T::AccountId) -> bool {
self.local
.borrow()
.get(account)
.map(|a| a.code_hash.is_some())
.unwrap_or_else(|| self.underlying.contract_exists(account))
}
fn get_balance(&self, account: &T::AccountId) -> BalanceOf<T> {
self.local
.borrow()
.get(account)
.and_then(|a| a.balance)
.unwrap_or_else(|| self.underlying.get_balance(account))
}
fn commit(&mut self, s: ChangeSet<T>) {
let mut local = self.local.borrow_mut();
for (address, changed) in s.into_iter() {
match local.entry(address) {
Entry::Occupied(e) => {
let mut value = e.into_mut();
value.balance = changed.balance.or(value.balance);
value.code_hash = changed.code_hash.or(value.code_hash);
value.rent_allowance = changed.rent_allowance.or(value.rent_allowance);
value.storage.extend(changed.storage.into_iter());
}
Entry::Vacant(e) => {
e.insert(changed);
}
}
}
}
}