// Copyright 2016 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 (
"container/heap"
"math"
"math/big"
"sort"
"github.com/ethereum/go-ethereum/core/types"
)
// nonceHeap is a heap.Interface implementation over 64bit unsigned integers for
// retrieving sorted transactions from the possibly gapped future queue.
type nonceHeap []uint64
func (h nonceHeap) Len() int { return len(h) }
func (h nonceHeap) Less(i, j int) bool { return h[i] < h[j] }
func (h nonceHeap) Swap(i, j int) { h[i], h[j] = h[j], h[i] }
func (h *nonceHeap) Push(x interface{}) {
*h = append(*h, x.(uint64))
}
func (h *nonceHeap) Pop() interface{} {
old := *h
n := len(old)
x := old[n-1]
*h = old[0 : n-1]
return x
}
// txSortedMap is a nonce->transaction hash map with a heap based index to allow
// iterating over the contents in a nonce-incrementing way.
type txSortedMap struct {
items map[uint64]*types.Transaction // Hash map storing the transaction data
index *nonceHeap // Heap of nonces of all the stored transactions (non-strict mode)
cache types.Transactions // Cache of the transactions already sorted
}
// newTxSortedMap creates a new sorted transaction map.
func newTxSortedMap() *txSortedMap {
return &txSortedMap{
items: make(map[uint64]*types.Transaction),
index: &nonceHeap{},
}
}
// Get retrieves the current transactions associated with the given nonce.
func (m *txSortedMap) Get(nonce uint64) *types.Transaction {
return m.items[nonce]
}
// Put inserts a new transaction into the map, also updating the map's nonce
// index. If a transaction already exists with the same nonce, it's overwritten.
func (m *txSortedMap) Put(tx *types.Transaction) {
nonce := tx.Nonce()
if m.items[nonce] == nil {
heap.Push(m.index, nonce)
}
m.items[nonce], m.cache = tx, nil
}
// Forward removes all transactions from the map with a nonce lower than the
// provided threshold. Every removed transaction is returned for any post-removal
// maintenance.
func (m *txSortedMap) Forward(threshold uint64) types.Transactions {
var removed types.Transactions
// Pop off heap items until the threshold is reached
for m.index.Len() > 0 && (*m.index)[0] < threshold {
nonce := heap.Pop(m.index).(uint64)
removed = append(removed, m.items[nonce])
delete(m.items, nonce)
}
// If we had a cached order, shift the front
if m.cache != nil {
m.cache = m.cache[len(removed):]
}
return removed
}
// Filter iterates over the list of transactions and removes all of them for which
// the specified function evaluates to true.
func (m *txSortedMap) Filter(filter func(*types.Transaction) bool) types.Transactions {
var removed types.Transactions
// Collect all the transactions to filter out
for nonce, tx := range m.items {
if filter(tx) {
removed = append(removed, tx)
delete(m.items, nonce)
}
}
// If transactions were removed, the heap and cache are ruined
if len(removed) > 0 {
*m.index = make([]uint64, 0, len(m.items))
for nonce, _ := range m.items {
*m.index = append(*m.index, nonce)
}
heap.Init(m.index)
m.cache = nil
}
return removed
}
// Cap places a hard limit on the number of items, returning all transactions
// exceeding that limit.
func (m *txSortedMap) Cap(threshold int) types.Transactions {
// Short circuit if the number of items is under the limit
if len(m.items) <= threshold {
return nil
}
// Otherwise gather and drop the highest nonce'd transactions
var drops types.Transactions
sort.Sort(*m.index)
for size := len(m.items); size > threshold; size-- {
drops = append(drops, m.items[(*m.index)[size-1]])
delete(m.items, (*m.index)[size-1])
}
*m.index = (*m.index)[:threshold]
heap.Init(m.index)
// If we had a cache, shift the back
if m.cache != nil {
m.cache = m.cache[:len(m.cache)-len(drops)]
}
return drops
}
// Remove deletes a transaction from the maintained map, returning whether the
// transaction was found.
func (m *txSortedMap) Remove(nonce uint64) bool {
// Short circuit if no transaction is present
_, ok := m.items[nonce]
if !ok {
return false
}
// Otherwise delete the transaction and fix the heap index
for i := 0; i < m.index.Len(); i++ {
if (*m.index)[i] == nonce {
heap.Remove(m.index, i)
break
}
}
delete(m.items, nonce)
m.cache = nil
return true
}
// Ready retrieves a sequentially increasing list of transactions starting at the
// provided nonce that is ready for processing. The returned transactions will be
// removed from the list.
//
// Note, all transactions with nonces lower than start will also be returned to
// prevent getting into and invalid state. This is not something that should ever
// happen but better to be self correcting than failing!
func (m *txSortedMap) Ready(start uint64) types.Transactions {
// Short circuit if no transactions are available
if m.index.Len() == 0 || (*m.index)[0] > start {
return nil
}
// Otherwise start accumulating incremental transactions
var ready types.Transactions
for next := (*m.index)[0]; m.index.Len() > 0 && (*m.index)[0] == next; next++ {
ready = append(ready, m.items[next])
delete(m.items, next)
heap.Pop(m.index)
}
m.cache = nil
return ready
}
// Len returns the length of the transaction map.
func (m *txSortedMap) Len() int {
return len(m.items)
}
// Flatten creates a nonce-sorted slice of transactions based on the loosely
// sorted internal representation. The result of the sorting is cached in case
// it's requested again before any modifications are made to the contents.
func (m *txSortedMap) Flatten() types.Transactions {
// If the sorting was not cached yet, create and cache it
if m.cache == nil {
m.cache = make(types.Transactions, 0, len(m.items))
for _, tx := range m.items {
m.cache = append(m.cache, tx)
}
sort.Sort(types.TxByNonce(m.cache))
}
// Copy the cache to prevent accidental modifications
txs := make(types.Transactions, len(m.cache))
copy(txs, m.cache)
return txs
}
// txList is a "list" of transactions belonging to an account, sorted by account
// nonce. The same type can be used both for storing contiguous transactions for
// the executable/pending queue; and for storing gapped transactions for the non-
// executable/future queue, with minor behavoiral changes.
type txList struct {
strict bool // Whether nonces are strictly continuous or not
txs *txSortedMap // Heap indexed sorted hash map of the transactions
costcap *big.Int // Price of the highest costing transaction (reset only if exceeds balance)
}
// newTxList create a new transaction list for maintaining nonce-indexable fast,
// gapped, sortable transaction lists.
func newTxList(strict bool) *txList {
return &txList{
strict: strict,
txs: newTxSortedMap(),
costcap: new(big.Int),
}
}
// Add tries to insert a new transaction into the list, returning whether the
// transaction was accepted, and if yes, any previous transaction it replaced.
//
// If the new transaction is accepted into the list, the lists' cost threshold
// is also potentially updated.
func (l *txList) Add(tx *types.Transaction) (bool, *types.Transaction) {
// If there's an older better transaction, abort
old := l.txs.Get(tx.Nonce())
if old != nil && old.GasPrice().Cmp(tx.GasPrice()) >= 0 {
return false, nil
}
// Otherwise overwrite the old transaction with the current one
l.txs.Put(tx)
if cost := tx.Cost(); l.costcap.Cmp(cost) < 0 {
l.costcap = cost
}
return true, old
}
// Forward removes all transactions from the list with a nonce lower than the
// provided threshold. Every removed transaction is returned for any post-removal
// maintenance.
func (l *txList) Forward(threshold uint64) types.Transactions {
return l.txs.Forward(threshold)
}
// Filter removes all transactions from the list with a cost higher than the
// provided threshold. Every removed transaction is returned for any post-removal
// maintenance. Strict-mode invalidated transactions are also returned.
//
// This method uses the cached costcap to quickly decide if there's even a point
// in calculating all the costs or if the balance covers all. If the threshold is
// lower than the costcap, the costcap will be reset to a new high after removing
// expensive the too transactions.
func (l *txList) Filter(threshold *big.Int) (types.Transactions, types.Transactions) {
// If all transactions are below the threshold, short circuit
if l.costcap.Cmp(threshold) <= 0 {
return nil, nil
}
l.costcap = new(big.Int).Set(threshold) // Lower the cap to the threshold
// Filter out all the transactions above the account's funds
removed := l.txs.Filter(func(tx *types.Transaction) bool { return tx.Cost().Cmp(threshold) > 0 })
// If the list was strict, filter anything above the lowest nonce
var invalids types.Transactions
if l.strict && len(removed) > 0 {
lowest := uint64(math.MaxUint64)
for _, tx := range removed {
if nonce := tx.Nonce(); lowest > nonce {
lowest = nonce
}
}
invalids = l.txs.Filter(func(tx *types.Transaction) bool { return tx.Nonce() > lowest })
}
return removed, invalids
}
// Cap places a hard limit on the number of items, returning all transactions
// exceeding that limit.
func (l *txList) Cap(threshold int) types.Transactions {
return l.txs.Cap(threshold)
}
// Remove deletes a transaction from the maintained list, returning whether the
// transaction was found, and also returning any transaction invalidated due to
// the deletion (strict mode only).
func (l *txList) Remove(tx *types.Transaction) (bool, types.Transactions) {
// Remove the transaction from the set
nonce := tx.Nonce()
if removed := l.txs.Remove(nonce); !removed {
return false, nil
}
// In strict mode, filter out non-executable transactions
if l.strict {
return true, l.txs.Filter(func(tx *types.Transaction) bool { return tx.Nonce() > nonce })
}
return true, nil
}
// Ready retrieves a sequentially increasing list of transactions starting at the
// provided nonce that is ready for processing. The returned transactions will be
// removed from the list.
//
// Note, all transactions with nonces lower than start will also be returned to
// prevent getting into and invalid state. This is not something that should ever
// happen but better to be self correcting than failing!
func (l *txList) Ready(start uint64) types.Transactions {
return l.txs.Ready(start)
}
// Len returns the length of the transaction list.
func (l *txList) Len() int {
return l.txs.Len()
}
// Empty returns whether the list of transactions is empty or not.
func (l *txList) Empty() bool {
return l.Len() == 0
}
// Flatten creates a nonce-sorted slice of transactions based on the loosely
// sorted internal representation. The result of the sorting is cached in case
// it's requested again before any modifications are made to the contents.
func (l *txList) Flatten() types.Transactions {
return l.txs.Flatten()
}
