neoneo-go/pkg/core/mempool/mem_pool.go
Roman Khimov 22f5667530 mempool: return fee along with tx when requesting tx
Users of GetVerifiedTransactions() don't want to recalculate tx fee and it's
nice to have it returned from TryGetValue() also sometimes.
2020-02-19 12:19:02 +03:00

286 lines
7.7 KiB
Go

package mempool
import (
"errors"
"sort"
"sync"
"time"
"github.com/CityOfZion/neo-go/pkg/core/transaction"
"github.com/CityOfZion/neo-go/pkg/util"
)
var (
// ErrConflict is returned when transaction being added is incompatible
// with the contents of the memory pool (using the same inputs as some
// other transaction in the pool)
ErrConflict = errors.New("conflicts with the memory pool")
// ErrDup is returned when transaction being added is already present
// in the memory pool.
ErrDup = errors.New("already in the memory pool")
// ErrOOM is returned when transaction just doesn't fit in the memory
// pool because of its capacity constraints.
ErrOOM = errors.New("out of memory")
)
// item represents a transaction in the the Memory pool.
type item struct {
txn *transaction.Transaction
timeStamp time.Time
perByteFee util.Fixed8
netFee util.Fixed8
isLowPrio bool
}
// items is a slice of item.
type items []*item
// TxWithFee combines transaction and its precalculated network fee.
type TxWithFee struct {
Tx *transaction.Transaction
Fee util.Fixed8
}
// Pool stores the unconfirms transactions.
type Pool struct {
lock sync.RWMutex
verifiedMap map[util.Uint256]*item
verifiedTxes items
capacity int
}
func (p items) Len() int { return len(p) }
func (p items) Swap(i, j int) { p[i], p[j] = p[j], p[i] }
func (p items) Less(i, j int) bool { return p[i].CompareTo(p[j]) < 0 }
// CompareTo returns the difference between two items.
// difference < 0 implies p < otherP.
// difference = 0 implies p = otherP.
// difference > 0 implies p > otherP.
func (p *item) CompareTo(otherP *item) int {
if otherP == nil {
return 1
}
if !p.isLowPrio && otherP.isLowPrio {
return 1
}
if p.isLowPrio && !otherP.isLowPrio {
return -1
}
if p.isLowPrio && otherP.isLowPrio {
thisIsClaimTx := p.txn.Type == transaction.ClaimType
otherIsClaimTx := otherP.txn.Type == transaction.ClaimType
if thisIsClaimTx != otherIsClaimTx {
// This is a claim Tx and other isn't.
if thisIsClaimTx {
return 1
}
// The other is claim Tx and this isn't.
return -1
}
}
// Fees sorted ascending.
if ret := p.perByteFee.CompareTo(otherP.perByteFee); ret != 0 {
return ret
}
if ret := p.netFee.CompareTo(otherP.netFee); ret != 0 {
return ret
}
// Transaction hash sorted descending.
return otherP.txn.Hash().CompareTo(p.txn.Hash())
}
// Count returns the total number of uncofirm transactions.
func (mp *Pool) Count() int {
mp.lock.RLock()
defer mp.lock.RUnlock()
return mp.count()
}
// count is an internal unlocked version of Count.
func (mp *Pool) count() int {
return len(mp.verifiedTxes)
}
// ContainsKey checks if a transactions hash is in the Pool.
func (mp *Pool) ContainsKey(hash util.Uint256) bool {
mp.lock.RLock()
defer mp.lock.RUnlock()
return mp.containsKey(hash)
}
// containsKey is an internal unlocked version of ContainsKey.
func (mp *Pool) containsKey(hash util.Uint256) bool {
if _, ok := mp.verifiedMap[hash]; ok {
return true
}
return false
}
// Add tries to add given transaction to the Pool.
func (mp *Pool) Add(t *transaction.Transaction, fee Feer) error {
var pItem = &item{
txn: t,
timeStamp: time.Now().UTC(),
perByteFee: fee.FeePerByte(t),
netFee: fee.NetworkFee(t),
}
pItem.isLowPrio = fee.IsLowPriority(pItem.netFee)
mp.lock.Lock()
if !mp.verifyInputs(t) {
mp.lock.Unlock()
return ErrConflict
}
if mp.containsKey(t.Hash()) {
mp.lock.Unlock()
return ErrDup
}
mp.verifiedMap[t.Hash()] = pItem
// Insert into sorted array (from max to min, that could also be done
// using sort.Sort(sort.Reverse()), but it incurs more overhead. Notice
// also that we're searching for position that is strictly more
// prioritized than our new item because we do expect a lot of
// transactions with the same priority and appending to the end of the
// slice is always more efficient.
n := sort.Search(len(mp.verifiedTxes), func(n int) bool {
return pItem.CompareTo(mp.verifiedTxes[n]) > 0
})
// We've reached our capacity already.
if len(mp.verifiedTxes) == mp.capacity {
// Less prioritized than the least prioritized we already have, won't fit.
if n == len(mp.verifiedTxes) {
mp.lock.Unlock()
return ErrOOM
}
// Ditch the last one.
unlucky := mp.verifiedTxes[len(mp.verifiedTxes)-1]
delete(mp.verifiedMap, unlucky.txn.Hash())
mp.verifiedTxes[len(mp.verifiedTxes)-1] = pItem
} else {
mp.verifiedTxes = append(mp.verifiedTxes, pItem)
}
if n != len(mp.verifiedTxes)-1 {
copy(mp.verifiedTxes[n+1:], mp.verifiedTxes[n:])
mp.verifiedTxes[n] = pItem
}
updateMempoolMetrics(len(mp.verifiedTxes))
mp.lock.Unlock()
return nil
}
// Remove removes an item from the mempool, if it exists there (and does
// nothing if it doesn't).
func (mp *Pool) Remove(hash util.Uint256) {
mp.lock.Lock()
if _, ok := mp.verifiedMap[hash]; ok {
var num int
delete(mp.verifiedMap, hash)
for num := range mp.verifiedTxes {
if hash.Equals(mp.verifiedTxes[num].txn.Hash()) {
break
}
}
if num < len(mp.verifiedTxes)-1 {
mp.verifiedTxes = append(mp.verifiedTxes[:num], mp.verifiedTxes[num+1:]...)
} else if num == len(mp.verifiedTxes)-1 {
mp.verifiedTxes = mp.verifiedTxes[:num]
}
}
updateMempoolMetrics(len(mp.verifiedTxes))
mp.lock.Unlock()
}
// RemoveStale filters verified transactions through the given function keeping
// only the transactions for which it returns a true result. It's used to quickly
// drop part of the mempool that is now invalid after the block acceptance.
func (mp *Pool) RemoveStale(isOK func(*transaction.Transaction) bool) {
mp.lock.Lock()
// We expect a lot of changes, so it's easier to allocate a new slice
// rather than move things in an old one.
newVerifiedTxes := make([]*item, 0, mp.capacity)
for _, itm := range mp.verifiedTxes {
if isOK(itm.txn) {
newVerifiedTxes = append(newVerifiedTxes, itm)
} else {
delete(mp.verifiedMap, itm.txn.Hash())
}
}
mp.verifiedTxes = newVerifiedTxes
mp.lock.Unlock()
}
// NewMemPool returns a new Pool struct.
func NewMemPool(capacity int) Pool {
return Pool{
verifiedMap: make(map[util.Uint256]*item),
verifiedTxes: make([]*item, 0, capacity),
capacity: capacity,
}
}
// TryGetValue returns a transaction and its fee if it exists in the memory pool.
func (mp *Pool) TryGetValue(hash util.Uint256) (*transaction.Transaction, util.Fixed8, bool) {
mp.lock.RLock()
defer mp.lock.RUnlock()
if pItem, ok := mp.verifiedMap[hash]; ok {
return pItem.txn, pItem.netFee, ok
}
return nil, 0, false
}
// GetVerifiedTransactions returns a slice of Input from all the transactions in the memory pool
// whose hash is not included in excludedHashes.
func (mp *Pool) GetVerifiedTransactions() []TxWithFee {
mp.lock.RLock()
defer mp.lock.RUnlock()
var t = make([]TxWithFee, len(mp.verifiedTxes))
for i := range mp.verifiedTxes {
t[i].Tx = mp.verifiedTxes[i].txn
t[i].Fee = mp.verifiedTxes[i].netFee
}
return t
}
// verifyInputs is an internal unprotected version of Verify.
func (mp *Pool) verifyInputs(tx *transaction.Transaction) bool {
if len(tx.Inputs) == 0 {
return true
}
for num := range mp.verifiedTxes {
txn := mp.verifiedTxes[num].txn
for i := range txn.Inputs {
for j := 0; j < len(tx.Inputs); j++ {
if txn.Inputs[i] == tx.Inputs[j] {
return false
}
}
}
}
return true
}
// Verify verifies if the inputs of a transaction tx are already used in any other transaction in the memory pool.
// If yes, the transaction tx is not a valid transaction and the function return false.
// If no, the transaction tx is a valid transaction and the function return true.
func (mp *Pool) Verify(tx *transaction.Transaction) bool {
mp.lock.RLock()
defer mp.lock.RUnlock()
return mp.verifyInputs(tx)
}