The core protocol of WoopChain
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woop/blockchain/utxopool.go

395 lines
12 KiB

package blockchain
import (
"bytes"
"encoding/gob"
"encoding/hex"
"fmt"
"sync"
)
// UTXOPool stores transactions and balance associated with each address.
type UTXOPool struct {
// Mapping from address to a map of transaction id to a map of the index of output
// array in that transaction to that balance.
/*
The 3-d map's structure:
address - [
txId1 - [
outputIndex1 - value1
outputIndex2 - value2
]
txId2 - [
outputIndex1 - value1
outputIndex2 - value2
]
]
*/
UtxoMap map[string]map[string]map[int]int
LockedUtxoMap map[string]map[string]map[int]int
ShardId uint32
mutex sync.Mutex
}
// VerifyTransactions verifies if a list of transactions valid for this shard.
func (utxoPool *UTXOPool) VerifyTransactions(transactions []*Transaction) bool {
spentTXOs := make(map[string]map[string]map[int]bool)
if utxoPool != nil {
for _, tx := range transactions {
if valid, crossShard := utxoPool.VerifyOneTransaction(tx, &spentTXOs); !crossShard && !valid {
return false
}
}
}
return true
}
// VerifyOneTransaction verifies if a list of transactions valid.
func (utxoPool *UTXOPool) VerifyOneTransaction(tx *Transaction, spentTXOs *map[string]map[string]map[int]bool) (valid, crossShard bool) {
if len(tx.Proofs) != 0 {
return utxoPool.VerifyUnlockTransaction(tx)
}
if spentTXOs == nil {
spentTXOs = &map[string]map[string]map[int]bool{}
}
inTotal := 0
// Calculate the sum of TxInput
for _, in := range tx.TxInput {
// Only check the input for my own shard.
if in.ShardId != utxoPool.ShardId {
crossShard = true
continue
}
inTxID := hex.EncodeToString(in.TxID[:])
index := in.TxOutputIndex
// Check if the transaction with the addres is spent or not.
if val, ok := (*spentTXOs)[in.Address][inTxID][index]; ok {
if val {
return false, crossShard
}
}
// Mark the transactions with the address and index spent.
if _, ok := (*spentTXOs)[in.Address]; !ok {
(*spentTXOs)[in.Address] = make(map[string]map[int]bool)
}
if _, ok := (*spentTXOs)[in.Address][inTxID]; !ok {
(*spentTXOs)[in.Address][inTxID] = make(map[int]bool)
}
(*spentTXOs)[in.Address][inTxID][index] = true
// Sum the balance up to the inTotal.
utxoPool.mutex.Lock()
if val, ok := utxoPool.UtxoMap[in.Address][inTxID][index]; ok {
inTotal += val
} else {
utxoPool.mutex.Unlock()
return false, crossShard
}
utxoPool.mutex.Unlock()
}
outTotal := 0
// Calculate the sum of TxOutput
for _, out := range tx.TxOutput {
outTotal += out.Value
}
if (crossShard && inTotal >= outTotal) || (!crossShard && inTotal != outTotal) {
return false, crossShard
}
if inTotal == 0 {
return false, false // Here crossShard is false, because if there is no business for this shard, it's effectively not crossShard no matter what.
}
return true, crossShard
}
// Verify a cross shard transaction that contains proofs for unlock-to-commit/abort.
func (utxoPool *UTXOPool) VerifyUnlockTransaction(tx *Transaction) (valid, crossShard bool) {
valid = true
crossShard = false // unlock transaction is treated as crossShard=false because it will be finalized now (doesn't need more steps)
txInputs := make(map[TXInput]bool)
for _, curProof := range tx.Proofs {
for _, txInput := range curProof.TxInput {
txInputs[txInput] = true
}
}
for _, txInput := range tx.TxInput {
val, ok := txInputs[txInput]
if !ok || !val {
valid = false
}
}
return
}
// Update Utxo balances with a list of new transactions.
func (utxoPool *UTXOPool) Update(transactions []*Transaction) {
if utxoPool != nil {
for _, tx := range transactions {
utxoPool.UpdateOneTransaction(tx)
}
}
}
// UpdateOneTransaction updates utxoPool in respect to the new Transaction.
func (utxoPool *UTXOPool) UpdateOneTransaction(tx *Transaction) {
isUnlockTx := len(tx.Proofs) != 0
unlockToCommit := true
if isUnlockTx {
for _, proof := range tx.Proofs {
if !proof.Accept {
unlockToCommit = false // if any proof is a rejection, they it's a unlock-to-abort tx. Otherwise, it's unlock-to-commit
}
}
}
isCrossShard := false
// check whether it's a cross shard tx.
for _, in := range tx.TxInput {
if in.ShardId != utxoPool.ShardId {
isCrossShard = true
break
}
}
isValidCrossShard := true
if isCrossShard {
// Check whether for this shard this cross transaction is valid or not.
for _, in := range tx.TxInput {
// Only check the input for my own shard.
if in.ShardId != utxoPool.ShardId {
continue
}
inTxID := hex.EncodeToString(in.TxID[:])
if _, ok := utxoPool.UtxoMap[in.Address][inTxID][in.TxOutputIndex]; !ok {
isValidCrossShard = false
}
}
}
utxoPool.mutex.Lock()
defer utxoPool.mutex.Unlock()
if utxoPool != nil {
txID := hex.EncodeToString(tx.ID[:])
// Remove
if !isUnlockTx {
if isValidCrossShard {
for _, in := range tx.TxInput {
// Only check the input for my own shard.
if in.ShardId != utxoPool.ShardId {
continue
}
// NOTE: for the locking phase of cross tx, the utxo is simply removed from the pool.
inTxID := hex.EncodeToString(in.TxID[:])
value := utxoPool.UtxoMap[in.Address][inTxID][in.TxOutputIndex]
utxoPool.DeleteOneUtxo(in.Address, inTxID, in.TxOutputIndex)
if isCrossShard {
// put the delete (locked) utxo into a separate locked utxo pool
inTxID := hex.EncodeToString(in.TxID[:])
if _, ok := utxoPool.LockedUtxoMap[in.Address]; !ok {
utxoPool.LockedUtxoMap[in.Address] = make(map[string]map[int]int)
utxoPool.LockedUtxoMap[in.Address][inTxID] = make(map[int]int)
}
if _, ok := utxoPool.LockedUtxoMap[in.Address][inTxID]; !ok {
utxoPool.LockedUtxoMap[in.Address][inTxID] = make(map[int]int)
}
utxoPool.LockedUtxoMap[in.Address][inTxID][in.TxOutputIndex] = value
}
}
}
}
// Update
if !isCrossShard || isUnlockTx {
if !unlockToCommit {
if isValidCrossShard {
// unlock-to-abort, bring back (unlock) the utxo input
for _, in := range tx.TxInput {
// Only unlock the input for my own shard.
if in.ShardId != utxoPool.ShardId {
continue
}
// Simply bring back the locked (removed) utxo
inTxID := hex.EncodeToString(in.TxID[:])
if _, ok := utxoPool.UtxoMap[in.Address]; !ok {
utxoPool.UtxoMap[in.Address] = make(map[string]map[int]int)
utxoPool.UtxoMap[in.Address][inTxID] = make(map[int]int)
}
if _, ok := utxoPool.UtxoMap[in.Address][inTxID]; !ok {
utxoPool.UtxoMap[in.Address][inTxID] = make(map[int]int)
}
value := utxoPool.LockedUtxoMap[in.Address][inTxID][in.TxOutputIndex]
utxoPool.UtxoMap[in.Address][inTxID][in.TxOutputIndex] = value
utxoPool.DeleteOneLockedUtxo(in.Address, inTxID, in.TxOutputIndex)
}
}
} else {
// normal utxo output update
for index, out := range tx.TxOutput {
// Only check the input for my own shard.
if out.ShardId != utxoPool.ShardId {
continue
}
if _, ok := utxoPool.UtxoMap[out.Address]; !ok {
utxoPool.UtxoMap[out.Address] = make(map[string]map[int]int)
utxoPool.UtxoMap[out.Address][txID] = make(map[int]int)
}
if _, ok := utxoPool.UtxoMap[out.Address][txID]; !ok {
utxoPool.UtxoMap[out.Address][txID] = make(map[int]int)
}
utxoPool.UtxoMap[out.Address][txID][index] = out.Value
}
}
} // If it's a cross shard locking Tx, then don't update so the input UTXOs are locked (removed), and the money is not spendable until unlock-to-commit or unlock-to-abort
}
}
// VerifyOneTransactionAndUpdate verifies and update a valid transaction.
// Return false if the transaction is not valid.
func (utxoPool *UTXOPool) VerifyOneTransactionAndUpdate(tx *Transaction) bool {
if valid, _ := utxoPool.VerifyOneTransaction(tx, nil); valid {
utxoPool.UpdateOneTransaction(tx)
return true
}
return false
}
// VerifyAndUpdate verifies a list of transactions and update utxoPool.
func (utxoPool *UTXOPool) VerifyAndUpdate(transactions []*Transaction) bool {
if utxoPool.VerifyTransactions(transactions) {
utxoPool.Update(transactions)
return true
}
return false
}
// CreateUTXOPoolFromTransaction a Utxo pool from a genesis transaction.
func CreateUTXOPoolFromTransaction(tx *Transaction, shardId uint32) *UTXOPool {
var utxoPool UTXOPool
txID := hex.EncodeToString(tx.ID[:])
utxoPool.UtxoMap = make(map[string]map[string]map[int]int)
utxoPool.LockedUtxoMap = make(map[string]map[string]map[int]int)
for index, out := range tx.TxOutput {
utxoPool.UtxoMap[out.Address] = make(map[string]map[int]int)
utxoPool.UtxoMap[out.Address][txID] = make(map[int]int)
utxoPool.UtxoMap[out.Address][txID][index] = out.Value
}
utxoPool.ShardId = shardId
return &utxoPool
}
// CreateUTXOPoolFromGenesisBlockChain a Utxo pool from a genesis blockchain.
func CreateUTXOPoolFromGenesisBlockChain(bc *Blockchain) *UTXOPool {
tx := bc.Blocks[0].Transactions[0]
shardId := bc.Blocks[0].ShardId
return CreateUTXOPoolFromTransaction(tx, shardId)
}
// SelectTransactionsForNewBlock returns a list of index of valid transactions for the new block.
func (utxoPool *UTXOPool) SelectTransactionsForNewBlock(transactions []*Transaction, maxNumTxs int) ([]*Transaction, []*Transaction, []*CrossShardTxAndProof) {
selected, unselected, crossShardTxs := []*Transaction{}, []*Transaction{}, []*CrossShardTxAndProof{}
spentTXOs := make(map[string]map[string]map[int]bool)
for _, tx := range transactions {
valid, crossShard := utxoPool.VerifyOneTransaction(tx, &spentTXOs)
if len(selected) < maxNumTxs {
if valid || crossShard {
selected = append(selected, tx)
if crossShard {
proof := CrossShardTxProof{Accept: valid, TxID: tx.ID, TxInput: getShardTxInput(tx, utxoPool.ShardId)}
txAndProof := CrossShardTxAndProof{tx, &proof}
crossShardTxs = append(crossShardTxs, &txAndProof)
}
} else {
unselected = append(unselected, tx)
}
} else {
// TODO: discard invalid transactions
unselected = append(unselected, tx)
}
}
return selected, unselected, crossShardTxs
}
func getShardTxInput(transaction *Transaction, shardId uint32) []TXInput {
result := []TXInput{}
for _, txInput := range transaction.TxInput {
if txInput.ShardId == shardId {
result = append(result, txInput)
}
}
return result
}
// DeleteOneBalanceItem deletes one balance item of UTXOPool and clean up if possible.
func (utxoPool *UTXOPool) DeleteOneUtxo(address, txID string, index int) {
delete(utxoPool.UtxoMap[address][txID], index)
if len(utxoPool.UtxoMap[address][txID]) == 0 {
delete(utxoPool.UtxoMap[address], txID)
if len(utxoPool.UtxoMap[address]) == 0 {
delete(utxoPool.UtxoMap, address)
}
}
}
// DeleteOneBalanceItem deletes one balance item of UTXOPool and clean up if possible.
func (utxoPool *UTXOPool) DeleteOneLockedUtxo(address, txID string, index int) {
delete(utxoPool.LockedUtxoMap[address][txID], index)
if len(utxoPool.LockedUtxoMap[address][txID]) == 0 {
delete(utxoPool.LockedUtxoMap[address], txID)
if len(utxoPool.LockedUtxoMap[address]) == 0 {
delete(utxoPool.LockedUtxoMap, address)
}
}
}
// CleanUp cleans up UTXOPool.
func (utxoPool *UTXOPool) CleanUp() {
for address, txMap := range utxoPool.UtxoMap {
for txid, outIndexes := range txMap {
for index, value := range outIndexes {
if value == 0 {
delete(utxoPool.UtxoMap[address][txid], index)
}
}
if len(utxoPool.UtxoMap[address][txid]) == 0 {
delete(utxoPool.UtxoMap[address], txid)
}
}
if len(utxoPool.UtxoMap[address]) == 0 {
delete(utxoPool.UtxoMap, address)
}
}
}
// Used for debugging.
func (utxoPool *UTXOPool) String() string {
res := ""
for address, v1 := range utxoPool.UtxoMap {
for txid, v2 := range v1 {
for index, value := range v2 {
res += fmt.Sprintf("address: %v, tx id: %v, index: %v, value: %v\n", address, txid, index, value)
}
}
}
return res
}
// Get a snapshot copy of the current pool
func (utxoPool *UTXOPool) GetSizeInByteOfUtxoMap() int {
utxoPool.mutex.Lock()
defer utxoPool.mutex.Unlock()
byteBuffer := bytes.NewBuffer([]byte{})
encoder := gob.NewEncoder(byteBuffer)
encoder.Encode(utxoPool.UtxoMap)
return len(byteBuffer.Bytes())
}