forked from TrueCloudLab/neoneo-go
480 lines
16 KiB
Go
480 lines
16 KiB
Go
package mempool
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import (
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"errors"
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"fmt"
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"math/big"
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"math/bits"
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"sort"
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"sync"
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"github.com/nspcc-dev/neo-go/pkg/core/transaction"
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"github.com/nspcc-dev/neo-go/pkg/util"
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)
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var (
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// ErrInsufficientFunds is returned when Sender is not able to pay for
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// transaction being added irrespective of the other contents of the
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// pool.
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ErrInsufficientFunds = errors.New("insufficient funds")
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// ErrConflict is returned when transaction being added is incompatible
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// with the contents of the memory pool (Sender doesn't have enough GAS
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// to pay for all transactions in the pool).
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ErrConflict = errors.New("conflicts with the memory pool")
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// ErrDup is returned when transaction being added is already present
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// in the memory pool.
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ErrDup = errors.New("already in the memory pool")
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// ErrOOM is returned when transaction just doesn't fit in the memory
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// pool because of its capacity constraints.
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ErrOOM = errors.New("out of memory")
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// ErrConflictsAttribute is returned when transaction conflicts with other transactions
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// due to its (or theirs) Conflicts attributes.
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ErrConflictsAttribute = errors.New("conflicts with memory pool due to Conflicts attribute")
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)
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// item represents a transaction in the the Memory pool.
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type item struct {
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txn *transaction.Transaction
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blockStamp uint32
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}
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// items is a slice of item.
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type items []item
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// utilityBalanceAndFees stores sender's balance and overall fees of
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// sender's transactions which are currently in mempool
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type utilityBalanceAndFees struct {
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balance *big.Int
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feeSum *big.Int
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}
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// Pool stores the unconfirms transactions.
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type Pool struct {
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lock sync.RWMutex
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verifiedMap map[util.Uint256]*transaction.Transaction
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verifiedTxes items
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fees map[util.Uint160]utilityBalanceAndFees
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// conflicts is a map of hashes of transactions which are conflicting with the mempooled ones.
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conflicts map[util.Uint256][]util.Uint256
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capacity int
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feePerByte int64
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resendThreshold uint32
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resendFunc func(*transaction.Transaction)
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}
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func (p items) Len() int { return len(p) }
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func (p items) Swap(i, j int) { p[i], p[j] = p[j], p[i] }
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func (p items) Less(i, j int) bool { return p[i].CompareTo(p[j]) < 0 }
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// CompareTo returns the difference between two items.
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// difference < 0 implies p < otherP.
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// difference = 0 implies p = otherP.
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// difference > 0 implies p > otherP.
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func (p item) CompareTo(otherP item) int {
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pHigh := p.txn.HasAttribute(transaction.HighPriority)
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otherHigh := otherP.txn.HasAttribute(transaction.HighPriority)
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if pHigh && !otherHigh {
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return 1
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} else if !pHigh && otherHigh {
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return -1
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}
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// Fees sorted ascending.
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if ret := int(p.txn.FeePerByte() - otherP.txn.FeePerByte()); ret != 0 {
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return ret
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}
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return int(p.txn.NetworkFee - otherP.txn.NetworkFee)
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}
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// Count returns the total number of uncofirm transactions.
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func (mp *Pool) Count() int {
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mp.lock.RLock()
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defer mp.lock.RUnlock()
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return mp.count()
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}
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// count is an internal unlocked version of Count.
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func (mp *Pool) count() int {
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return len(mp.verifiedTxes)
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}
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// ContainsKey checks if a transactions hash is in the Pool.
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func (mp *Pool) ContainsKey(hash util.Uint256) bool {
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mp.lock.RLock()
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defer mp.lock.RUnlock()
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return mp.containsKey(hash)
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}
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// containsKey is an internal unlocked version of ContainsKey.
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func (mp *Pool) containsKey(hash util.Uint256) bool {
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if _, ok := mp.verifiedMap[hash]; ok {
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return true
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}
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return false
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}
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// HasConflicts returns true if transaction is already in pool or in the Conflicts attributes
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// of pooled transactions or has Conflicts attributes for pooled transactions.
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func (mp *Pool) HasConflicts(t *transaction.Transaction, fee Feer) bool {
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mp.lock.RLock()
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defer mp.lock.RUnlock()
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if mp.containsKey(t.Hash()) {
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return true
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}
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if fee.P2PSigExtensionsEnabled() {
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// do not check sender's signature and fee
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if _, ok := mp.conflicts[t.Hash()]; ok {
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return true
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}
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for _, attr := range t.GetAttributes(transaction.ConflictsT) {
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if mp.containsKey(attr.Value.(*transaction.Conflicts).Hash) {
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return true
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}
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}
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}
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return false
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}
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// tryAddSendersFee tries to add system fee and network fee to the total sender`s fee in mempool
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// and returns false if both balance check is required and sender has not enough GAS to pay
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func (mp *Pool) tryAddSendersFee(tx *transaction.Transaction, feer Feer, needCheck bool) bool {
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senderFee, ok := mp.fees[tx.Sender()]
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if !ok {
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senderFee.balance = feer.GetUtilityTokenBalance(tx.Sender())
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senderFee.feeSum = big.NewInt(0)
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mp.fees[tx.Sender()] = senderFee
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}
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if needCheck {
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newFeeSum, err := checkBalance(tx, senderFee)
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if err != nil {
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return false
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}
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senderFee.feeSum.Set(newFeeSum)
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} else {
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senderFee.feeSum.Add(senderFee.feeSum, big.NewInt(tx.SystemFee+tx.NetworkFee))
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}
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return true
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}
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// checkBalance returns new cumulative fee balance for account or an error in
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// case sender doesn't have enough GAS to pay for the transaction.
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func checkBalance(tx *transaction.Transaction, balance utilityBalanceAndFees) (*big.Int, error) {
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txFee := big.NewInt(tx.SystemFee + tx.NetworkFee)
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if balance.balance.Cmp(txFee) < 0 {
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return nil, ErrInsufficientFunds
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}
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txFee.Add(txFee, balance.feeSum)
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if balance.balance.Cmp(txFee) < 0 {
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return nil, ErrConflict
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}
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return txFee, nil
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}
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// Add tries to add given transaction to the Pool.
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func (mp *Pool) Add(t *transaction.Transaction, fee Feer) error {
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var pItem = item{
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txn: t,
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blockStamp: fee.BlockHeight(),
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}
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mp.lock.Lock()
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if mp.containsKey(t.Hash()) {
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mp.lock.Unlock()
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return ErrDup
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}
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conflictsToBeRemoved, err := mp.checkTxConflicts(t, fee)
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if err != nil {
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mp.lock.Unlock()
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return err
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}
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mp.verifiedMap[t.Hash()] = t
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if fee.P2PSigExtensionsEnabled() {
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// Remove conflicting transactions.
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for _, conflictingTx := range conflictsToBeRemoved {
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mp.removeInternal(conflictingTx.Hash(), fee)
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}
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}
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// Insert into sorted array (from max to min, that could also be done
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// using sort.Sort(sort.Reverse()), but it incurs more overhead. Notice
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// also that we're searching for position that is strictly more
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// prioritized than our new item because we do expect a lot of
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// transactions with the same priority and appending to the end of the
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// slice is always more efficient.
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n := sort.Search(len(mp.verifiedTxes), func(n int) bool {
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return pItem.CompareTo(mp.verifiedTxes[n]) > 0
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})
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// We've reached our capacity already.
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if len(mp.verifiedTxes) == mp.capacity {
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// Less prioritized than the least prioritized we already have, won't fit.
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if n == len(mp.verifiedTxes) {
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mp.lock.Unlock()
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return ErrOOM
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}
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// Ditch the last one.
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unlucky := mp.verifiedTxes[len(mp.verifiedTxes)-1]
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delete(mp.verifiedMap, unlucky.txn.Hash())
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if fee.P2PSigExtensionsEnabled() {
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mp.removeConflictsOf(unlucky.txn)
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}
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mp.verifiedTxes[len(mp.verifiedTxes)-1] = pItem
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} else {
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mp.verifiedTxes = append(mp.verifiedTxes, pItem)
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}
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if n != len(mp.verifiedTxes)-1 {
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copy(mp.verifiedTxes[n+1:], mp.verifiedTxes[n:])
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mp.verifiedTxes[n] = pItem
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}
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if fee.P2PSigExtensionsEnabled() {
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// Add conflicting hashes to the mp.conflicts list.
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for _, attr := range t.GetAttributes(transaction.ConflictsT) {
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hash := attr.Value.(*transaction.Conflicts).Hash
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mp.conflicts[hash] = append(mp.conflicts[hash], t.Hash())
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}
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}
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// we already checked balance in checkTxConflicts, so don't need to check again
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mp.tryAddSendersFee(pItem.txn, fee, false)
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updateMempoolMetrics(len(mp.verifiedTxes))
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mp.lock.Unlock()
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return nil
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}
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// Remove removes an item from the mempool, if it exists there (and does
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// nothing if it doesn't).
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func (mp *Pool) Remove(hash util.Uint256, feer Feer) {
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mp.lock.Lock()
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mp.removeInternal(hash, feer)
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mp.lock.Unlock()
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}
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// removeInternal is an internal unlocked representation of Remove
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func (mp *Pool) removeInternal(hash util.Uint256, feer Feer) {
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if tx, ok := mp.verifiedMap[hash]; ok {
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var num int
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delete(mp.verifiedMap, hash)
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for num = range mp.verifiedTxes {
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if hash.Equals(mp.verifiedTxes[num].txn.Hash()) {
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break
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}
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}
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if num < len(mp.verifiedTxes)-1 {
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mp.verifiedTxes = append(mp.verifiedTxes[:num], mp.verifiedTxes[num+1:]...)
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} else if num == len(mp.verifiedTxes)-1 {
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mp.verifiedTxes = mp.verifiedTxes[:num]
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}
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senderFee := mp.fees[tx.Sender()]
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senderFee.feeSum.Sub(senderFee.feeSum, big.NewInt(tx.SystemFee+tx.NetworkFee))
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mp.fees[tx.Sender()] = senderFee
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if feer.P2PSigExtensionsEnabled() {
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// remove all conflicting hashes from mp.conflicts list
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mp.removeConflictsOf(tx)
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}
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}
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updateMempoolMetrics(len(mp.verifiedTxes))
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}
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// RemoveStale filters verified transactions through the given function keeping
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// only the transactions for which it returns a true result. It's used to quickly
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// drop part of the mempool that is now invalid after the block acceptance.
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func (mp *Pool) RemoveStale(isOK func(*transaction.Transaction) bool, feer Feer) {
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mp.lock.Lock()
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policyChanged := mp.loadPolicy(feer)
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// We can reuse already allocated slice
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// because items are iterated one-by-one in increasing order.
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newVerifiedTxes := mp.verifiedTxes[:0]
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mp.fees = make(map[util.Uint160]utilityBalanceAndFees) // it'd be nice to reuse existing map, but we can't easily clear it
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if feer.P2PSigExtensionsEnabled() {
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mp.conflicts = make(map[util.Uint256][]util.Uint256)
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}
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height := feer.BlockHeight()
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var staleTxs []*transaction.Transaction
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for _, itm := range mp.verifiedTxes {
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if isOK(itm.txn) && mp.checkPolicy(itm.txn, policyChanged) && mp.tryAddSendersFee(itm.txn, feer, true) {
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newVerifiedTxes = append(newVerifiedTxes, itm)
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if feer.P2PSigExtensionsEnabled() {
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for _, attr := range itm.txn.GetAttributes(transaction.ConflictsT) {
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hash := attr.Value.(*transaction.Conflicts).Hash
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mp.conflicts[hash] = append(mp.conflicts[hash], itm.txn.Hash())
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}
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}
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if mp.resendThreshold != 0 {
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// tx is resend at resendThreshold, 2*resendThreshold, 4*resendThreshold ...
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// so quotient must be a power of two.
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diff := (height - itm.blockStamp)
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if diff%mp.resendThreshold == 0 && bits.OnesCount32(diff/mp.resendThreshold) == 1 {
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staleTxs = append(staleTxs, itm.txn)
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}
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}
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} else {
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delete(mp.verifiedMap, itm.txn.Hash())
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}
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}
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if len(staleTxs) != 0 {
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go mp.resendStaleTxs(staleTxs)
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}
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mp.verifiedTxes = newVerifiedTxes
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mp.lock.Unlock()
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}
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// loadPolicy updates feePerByte field and returns whether policy has been
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// changed.
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func (mp *Pool) loadPolicy(feer Feer) bool {
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newFeePerByte := feer.FeePerByte()
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if newFeePerByte > mp.feePerByte {
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mp.feePerByte = newFeePerByte
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return true
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}
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return false
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}
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// checkPolicy checks whether transaction fits policy.
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func (mp *Pool) checkPolicy(tx *transaction.Transaction, policyChanged bool) bool {
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if !policyChanged || tx.FeePerByte() >= mp.feePerByte {
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return true
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}
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return false
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}
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// New returns a new Pool struct.
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func New(capacity int) *Pool {
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return &Pool{
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verifiedMap: make(map[util.Uint256]*transaction.Transaction),
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verifiedTxes: make([]item, 0, capacity),
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capacity: capacity,
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fees: make(map[util.Uint160]utilityBalanceAndFees),
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conflicts: make(map[util.Uint256][]util.Uint256),
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}
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}
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// SetResendThreshold sets threshold after which transaction will be considered stale
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// and returned for retransmission by `GetStaleTransactions`.
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func (mp *Pool) SetResendThreshold(h uint32, f func(*transaction.Transaction)) {
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mp.lock.Lock()
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defer mp.lock.Unlock()
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mp.resendThreshold = h
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mp.resendFunc = f
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}
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func (mp *Pool) resendStaleTxs(txs []*transaction.Transaction) {
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for i := range txs {
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mp.resendFunc(txs[i])
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}
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}
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// TryGetValue returns a transaction and its fee if it exists in the memory pool.
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func (mp *Pool) TryGetValue(hash util.Uint256) (*transaction.Transaction, bool) {
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mp.lock.RLock()
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defer mp.lock.RUnlock()
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if tx, ok := mp.verifiedMap[hash]; ok {
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return tx, ok
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}
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return nil, false
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}
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// GetVerifiedTransactions returns a slice of transactions with their fees.
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func (mp *Pool) GetVerifiedTransactions() []*transaction.Transaction {
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mp.lock.RLock()
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defer mp.lock.RUnlock()
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var t = make([]*transaction.Transaction, len(mp.verifiedTxes))
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for i := range mp.verifiedTxes {
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t[i] = mp.verifiedTxes[i].txn
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}
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return t
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}
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// checkTxConflicts is an internal unprotected version of Verify. It takes into
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// consideration conflicting transactions which are about to be removed from mempool.
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func (mp *Pool) checkTxConflicts(tx *transaction.Transaction, fee Feer) ([]*transaction.Transaction, error) {
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actualSenderFee, ok := mp.fees[tx.Sender()]
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if !ok {
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actualSenderFee.balance = fee.GetUtilityTokenBalance(tx.Sender())
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actualSenderFee.feeSum = big.NewInt(0)
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}
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var expectedSenderFee utilityBalanceAndFees
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// Check Conflicts attributes.
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var conflictsToBeRemoved []*transaction.Transaction
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if fee.P2PSigExtensionsEnabled() {
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// Step 1: check if `tx` was in attributes of mempooled transactions.
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if conflictingHashes, ok := mp.conflicts[tx.Hash()]; ok {
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for _, hash := range conflictingHashes {
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existingTx := mp.verifiedMap[hash]
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if existingTx.HasSigner(tx.Sender()) && existingTx.NetworkFee > tx.NetworkFee {
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return nil, fmt.Errorf("%w: conflicting transaction %s has bigger network fee", ErrConflictsAttribute, existingTx.Hash().StringBE())
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}
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conflictsToBeRemoved = append(conflictsToBeRemoved, existingTx)
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}
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}
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// Step 2: check if mempooled transactions were in `tx`'s attributes.
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for _, attr := range tx.GetAttributes(transaction.ConflictsT) {
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hash := attr.Value.(*transaction.Conflicts).Hash
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existingTx, ok := mp.verifiedMap[hash]
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if !ok {
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continue
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}
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if !tx.HasSigner(existingTx.Sender()) {
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return nil, fmt.Errorf("%w: not signed by the sender of conflicting transaction %s", ErrConflictsAttribute, existingTx.Hash().StringBE())
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}
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if existingTx.NetworkFee >= tx.NetworkFee {
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return nil, fmt.Errorf("%w: conflicting transaction %s has bigger or equal network fee", ErrConflictsAttribute, existingTx.Hash().StringBE())
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}
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conflictsToBeRemoved = append(conflictsToBeRemoved, existingTx)
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}
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// Step 3: take into account sender's conflicting transactions before balance check.
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expectedSenderFee = utilityBalanceAndFees{
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balance: new(big.Int).Set(actualSenderFee.balance),
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feeSum: new(big.Int).Set(actualSenderFee.feeSum),
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}
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for _, conflictingTx := range conflictsToBeRemoved {
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if conflictingTx.Sender().Equals(tx.Sender()) {
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expectedSenderFee.feeSum.Sub(expectedSenderFee.feeSum, big.NewInt(conflictingTx.SystemFee+conflictingTx.NetworkFee))
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}
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}
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} else {
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expectedSenderFee = actualSenderFee
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}
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_, err := checkBalance(tx, expectedSenderFee)
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return conflictsToBeRemoved, err
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}
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// Verify checks if a Sender of tx is able to pay for it (and all the other
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// transactions in the pool). If yes, the transaction tx is a valid
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// transaction and the function returns true. If no, the transaction tx is
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// considered to be invalid the function returns false.
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func (mp *Pool) Verify(tx *transaction.Transaction, feer Feer) bool {
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mp.lock.RLock()
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defer mp.lock.RUnlock()
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_, err := mp.checkTxConflicts(tx, feer)
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return err == nil
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}
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// removeConflictsOf removes hash of the given transaction from the conflicts list
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// for each Conflicts attribute.
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func (mp *Pool) removeConflictsOf(tx *transaction.Transaction) {
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// remove all conflicting hashes from mp.conflicts list
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for _, attr := range tx.GetAttributes(transaction.ConflictsT) {
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conflictsHash := attr.Value.(*transaction.Conflicts).Hash
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if len(mp.conflicts[conflictsHash]) == 1 {
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delete(mp.conflicts, conflictsHash)
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continue
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}
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for i, existingHash := range mp.conflicts[conflictsHash] {
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if existingHash == tx.Hash() {
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// tx.Hash can occur in the conflicting hashes array only once, because we can't add the same transaction to the mempol twice
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mp.conflicts[conflictsHash] = append(mp.conflicts[conflictsHash][:i], mp.conflicts[conflictsHash][i+1:]...)
|
|
break
|
|
}
|
|
}
|
|
}
|
|
}
|