// Copyright 2019 The go-ethereum Authors // This file is part of the go-ethereum library. // // The go-ethereum library is free software: you can redistribute it and/or modify // it under the terms of the GNU Lesser General Public License as published by // the Free Software Foundation, either version 3 of the License, or // (at your option) any later version. // // The go-ethereum library 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 Lesser General Public License for more details. // // You should have received a copy of the GNU Lesser General Public License // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>. package core import ( "sync" "github.com/ava-labs/coreth/core/state" "github.com/ava-labs/go-ethereum/common" ) // txNoncer is a tiny virtual state database to manage the executable nonces of // accounts in the pool, falling back to reading from a real state database if // an account is unknown. type txNoncer struct { fallback *state.StateDB nonces map[common.Address]uint64 lock sync.Mutex } // newTxNoncer creates a new virtual state database to track the pool nonces. func newTxNoncer(statedb *state.StateDB) *txNoncer { return &txNoncer{ fallback: statedb.Copy(), nonces: make(map[common.Address]uint64), } } // get returns the current nonce of an account, falling back to a real state // database if the account is unknown. func (txn *txNoncer) get(addr common.Address) uint64 { // We use mutex for get operation is the underlying // state will mutate db even for read access. txn.lock.Lock() defer txn.lock.Unlock() if _, ok := txn.nonces[addr]; !ok { txn.nonces[addr] = txn.fallback.GetNonce(addr) } return txn.nonces[addr] } // set inserts a new virtual nonce into the virtual state database to be returned // whenever the pool requests it instead of reaching into the real state database. func (txn *txNoncer) set(addr common.Address, nonce uint64) { txn.lock.Lock() defer txn.lock.Unlock() txn.nonces[addr] = nonce } // setIfLower updates a new virtual nonce into the virtual state database if the // the new one is lower. func (txn *txNoncer) setIfLower(addr common.Address, nonce uint64) { txn.lock.Lock() defer txn.lock.Unlock() if _, ok := txn.nonces[addr]; !ok { txn.nonces[addr] = txn.fallback.GetNonce(addr) } if txn.nonces[addr] <= nonce { return } txn.nonces[addr] = nonce }