core: make txpool operate on immutable state

1 files changed, 114 insertions, 89 deletions

diff --git a/core/tx_pool.go b/core/tx_pool.go
index d835c94d1..f41fbe069 100644
--- a/core/tx_pool.go
+++ b/core/tx_pool.go
@@ -105,10 +105,11 @@ var (
 // blockChain provides the state of blockchain and current gas limit to do
 // some pre checks in tx pool and event subscribers.
 type blockChain interface {
-	State() (*state.StateDB, error)
-	GasLimit() *big.Int
+	CurrentHeader() *types.Header
 	SubscribeChainHeadEvent(ch chan<- ChainHeadEvent) event.Subscription
-	SubscribeRemovedTxEvent(ch chan<- RemovedTransactionEvent) event.Subscription
+
+	GetBlock(hash common.Hash, number uint64) *types.Block
+	StateAt(root common.Hash) (*state.StateDB, error)
 }
 
 // TxPoolConfig are the configuration parameters of the transaction pool.
@@ -174,18 +175,19 @@ func (config *TxPoolConfig) sanitize() TxPoolConfig {
 type TxPool struct {
 	config       TxPoolConfig
 	chainconfig  *params.ChainConfig
-	blockChain   blockChain
-	pendingState *state.ManagedState
+	chain        blockChain
 	gasPrice     *big.Int
 	txFeed       event.Feed
 	scope        event.SubscriptionScope
 	chainHeadCh  chan ChainHeadEvent
 	chainHeadSub event.Subscription
-	rmTxCh       chan RemovedTransactionEvent
-	rmTxSub      event.Subscription
 	signer       types.Signer
 	mu           sync.RWMutex
 
+	currentState  *state.StateDB      // Current state in the blockchain head
+	pendingState  *state.ManagedState // Pending state tracking virtual nonces
+	currentMaxGas *big.Int            // Current gas limit for transaction caps
+
 	locals  *accountSet // Set of local transaction to exepmt from evicion rules
 	journal *txJournal  // Journal of local transaction to back up to disk
 
@@ -202,28 +204,26 @@ type TxPool struct {
 
 // NewTxPool creates a new transaction pool to gather, sort and filter inbound
 // trnsactions from the network.
-func NewTxPool(config TxPoolConfig, chainconfig *params.ChainConfig, blockChain blockChain) *TxPool {
+func NewTxPool(config TxPoolConfig, chainconfig *params.ChainConfig, chain blockChain) *TxPool {
 	// Sanitize the input to ensure no vulnerable gas prices are set
 	config = (&config).sanitize()
 
 	// Create the transaction pool with its initial settings
 	pool := &TxPool{
-		config:       config,
-		chainconfig:  chainconfig,
-		blockChain:   blockChain,
-		signer:       types.NewEIP155Signer(chainconfig.ChainId),
-		pending:      make(map[common.Address]*txList),
-		queue:        make(map[common.Address]*txList),
-		beats:        make(map[common.Address]time.Time),
-		all:          make(map[common.Hash]*types.Transaction),
-		chainHeadCh:  make(chan ChainHeadEvent, chainHeadChanSize),
-		rmTxCh:       make(chan RemovedTransactionEvent, rmTxChanSize),
-		gasPrice:     new(big.Int).SetUint64(config.PriceLimit),
-		pendingState: nil,
+		config:      config,
+		chainconfig: chainconfig,
+		chain:       chain,
+		signer:      types.NewEIP155Signer(chainconfig.ChainId),
+		pending:     make(map[common.Address]*txList),
+		queue:       make(map[common.Address]*txList),
+		beats:       make(map[common.Address]time.Time),
+		all:         make(map[common.Hash]*types.Transaction),
+		chainHeadCh: make(chan ChainHeadEvent, chainHeadChanSize),
+		gasPrice:    new(big.Int).SetUint64(config.PriceLimit),
 	}
 	pool.locals = newAccountSet(pool.signer)
 	pool.priced = newTxPricedList(&pool.all)
-	pool.reset()
+	pool.reset(nil, chain.CurrentHeader())
 
 	// If local transactions and journaling is enabled, load from disk
 	if !config.NoLocals && config.Journal != "" {
@@ -237,8 +237,8 @@ func NewTxPool(config TxPoolConfig, chainconfig *params.ChainConfig, blockChain
 		}
 	}
 	// Subscribe events from blockchain
-	pool.chainHeadSub = pool.blockChain.SubscribeChainHeadEvent(pool.chainHeadCh)
-	pool.rmTxSub = pool.blockChain.SubscribeRemovedTxEvent(pool.rmTxCh)
+	pool.chainHeadSub = pool.chain.SubscribeChainHeadEvent(pool.chainHeadCh)
+
 	// Start the event loop and return
 	pool.wg.Add(1)
 	go pool.loop()
@@ -264,31 +264,28 @@ func (pool *TxPool) loop() {
 	journal := time.NewTicker(pool.config.Rejournal)
 	defer journal.Stop()
 
+	// Track the previous head headers for transaction reorgs
+	head := pool.chain.CurrentHeader()
+
 	// Keep waiting for and reacting to the various events
 	for {
 		select {
 		// Handle ChainHeadEvent
 		case ev := <-pool.chainHeadCh:
-			pool.mu.Lock()
 			if ev.Block != nil {
+				pool.mu.Lock()
 				if pool.chainconfig.IsHomestead(ev.Block.Number()) {
 					pool.homestead = true
 				}
+				pool.reset(head, ev.Block.Header())
+				head = ev.Block.Header()
 
+				pool.mu.Unlock()
 			}
-			pool.reset()
-			pool.mu.Unlock()
 		// Be unsubscribed due to system stopped
 		case <-pool.chainHeadSub.Err():
 			return
 
-		// Handle RemovedTransactionEvent
-		case ev := <-pool.rmTxCh:
-			pool.addTxs(ev.Txs, false)
-		// Be unsubscribed due to system stopped
-		case <-pool.rmTxSub.Err():
-			return
-
 		// Handle stats reporting ticks
 		case <-report.C:
 			pool.mu.RLock()
@@ -333,28 +330,76 @@ func (pool *TxPool) loop() {
 
 // lockedReset is a wrapper around reset to allow calling it in a thread safe
 // manner. This method is only ever used in the tester!
-func (pool *TxPool) lockedReset() {
+func (pool *TxPool) lockedReset(oldHead, newHead *types.Header) {
 	pool.mu.Lock()
 	defer pool.mu.Unlock()
 
-	pool.reset()
+	pool.reset(oldHead, newHead)
 }
 
 // reset retrieves the current state of the blockchain and ensures the content
 // of the transaction pool is valid with regard to the chain state.
-func (pool *TxPool) reset() {
-	currentState, err := pool.blockChain.State()
+func (pool *TxPool) reset(oldHead, newHead *types.Header) {
+	// If we're reorging an old state, reinject all dropped transactions
+	var reinject types.Transactions
+
+	if oldHead != nil && oldHead.Hash() != newHead.ParentHash {
+		var discarded, included types.Transactions
+
+		var (
+			rem = pool.chain.GetBlock(oldHead.Hash(), oldHead.Number.Uint64())
+			add = pool.chain.GetBlock(newHead.Hash(), newHead.Number.Uint64())
+		)
+		for rem.NumberU64() > add.NumberU64() {
+			discarded = append(discarded, rem.Transactions()...)
+			if rem = pool.chain.GetBlock(rem.ParentHash(), rem.NumberU64()-1); rem == nil {
+				log.Error("Unrooted old chain seen by tx pool", "block", oldHead.Number, "hash", oldHead.Hash())
+				return
+			}
+		}
+		for add.NumberU64() > rem.NumberU64() {
+			included = append(included, add.Transactions()...)
+			if add = pool.chain.GetBlock(add.ParentHash(), add.NumberU64()-1); add == nil {
+				log.Error("Unrooted new chain seen by tx pool", "block", newHead.Number, "hash", newHead.Hash())
+				return
+			}
+		}
+		for rem.Hash() != add.Hash() {
+			discarded = append(discarded, rem.Transactions()...)
+			if rem = pool.chain.GetBlock(rem.ParentHash(), rem.NumberU64()-1); rem == nil {
+				log.Error("Unrooted old chain seen by tx pool", "block", oldHead.Number, "hash", oldHead.Hash())
+				return
+			}
+			included = append(included, add.Transactions()...)
+			if add = pool.chain.GetBlock(add.ParentHash(), add.NumberU64()-1); add == nil {
+				log.Error("Unrooted new chain seen by tx pool", "block", newHead.Number, "hash", newHead.Hash())
+				return
+			}
+		}
+		reinject = types.TxDifference(discarded, included)
+	}
+	// Initialize the internal state to the current head
+	if newHead == nil {
+		newHead = pool.chain.CurrentHeader() // Special case during testing
+	}
+	statedb, err := pool.chain.StateAt(newHead.Root)
 	if err != nil {
-		log.Error("Failed reset txpool state", "err", err)
+		log.Error("Failed to reset txpool state", "err", err)
 		return
 	}
-	pool.pendingState = state.ManageState(currentState)
+	pool.currentState = statedb
+	pool.pendingState = state.ManageState(statedb)
+	pool.currentMaxGas = newHead.GasLimit
+
+	// Inject any transactions discarded due to reorgs
+	log.Debug("Reinjecting stale transactions", "count", len(reinject))
+	pool.addTxsLocked(reinject, false)
 
 	// validate the pool of pending transactions, this will remove
 	// any transactions that have been included in the block or
 	// have been invalidated because of another transaction (e.g.
 	// higher gas price)
-	pool.demoteUnexecutables(currentState)
+	pool.demoteUnexecutables()
 
 	// Update all accounts to the latest known pending nonce
 	for addr, list := range pool.pending {
@@ -363,16 +408,16 @@ func (pool *TxPool) reset() {
 	}
 	// Check the queue and move transactions over to the pending if possible
 	// or remove those that have become invalid
-	pool.promoteExecutables(currentState, nil)
+	pool.promoteExecutables(nil)
 }
 
 // Stop terminates the transaction pool.
 func (pool *TxPool) Stop() {
 	// Unsubscribe all subscriptions registered from txpool
 	pool.scope.Close()
+
 	// Unsubscribe subscriptions registered from blockchain
 	pool.chainHeadSub.Unsubscribe()
-	pool.rmTxSub.Unsubscribe()
 	pool.wg.Wait()
 
 	if pool.journal != nil {
@@ -442,8 +487,8 @@ func (pool *TxPool) stats() (int, int) {
 // Content retrieves the data content of the transaction pool, returning all the
 // pending as well as queued transactions, grouped by account and sorted by nonce.
 func (pool *TxPool) Content() (map[common.Address]types.Transactions, map[common.Address]types.Transactions) {
-	pool.mu.RLock()
-	defer pool.mu.RUnlock()
+	pool.mu.Lock()
+	defer pool.mu.Unlock()
 
 	pending := make(map[common.Address]types.Transactions)
 	for addr, list := range pool.pending {
@@ -499,7 +544,7 @@ func (pool *TxPool) validateTx(tx *types.Transaction, local bool) error {
 		return ErrNegativeValue
 	}
 	// Ensure the transaction doesn't exceed the current block limit gas.
-	if pool.blockChain.GasLimit().Cmp(tx.Gas()) < 0 {
+	if pool.currentMaxGas.Cmp(tx.Gas()) < 0 {
 		return ErrGasLimit
 	}
 	// Make sure the transaction is signed properly
@@ -513,16 +558,12 @@ func (pool *TxPool) validateTx(tx *types.Transaction, local bool) error {
 		return ErrUnderpriced
 	}
 	// Ensure the transaction adheres to nonce ordering
-	currentState, err := pool.blockChain.State()
-	if err != nil {
-		return err
-	}
-	if currentState.GetNonce(from) > tx.Nonce() {
+	if pool.currentState.GetNonce(from) > tx.Nonce() {
 		return ErrNonceTooLow
 	}
 	// Transactor should have enough funds to cover the costs
 	// cost == V + GP * GL
-	if currentState.GetBalance(from).Cmp(tx.Cost()) < 0 {
+	if pool.currentState.GetBalance(from).Cmp(tx.Cost()) < 0 {
 		return ErrInsufficientFunds
 	}
 	intrGas := IntrinsicGas(tx.Data(), tx.To() == nil, pool.homestead)
@@ -721,12 +762,8 @@ func (pool *TxPool) addTx(tx *types.Transaction, local bool) error {
 	}
 	// If we added a new transaction, run promotion checks and return
 	if !replace {
-		state, err := pool.blockChain.State()
-		if err != nil {
-			return err
-		}
 		from, _ := types.Sender(pool.signer, tx) // already validated
-		pool.promoteExecutables(state, []common.Address{from})
+		pool.promoteExecutables([]common.Address{from})
 	}
 	return nil
 }
@@ -736,6 +773,12 @@ func (pool *TxPool) addTxs(txs []*types.Transaction, local bool) error {
 	pool.mu.Lock()
 	defer pool.mu.Unlock()
 
+	return pool.addTxsLocked(txs, local)
+}
+
+// addTxsLocked attempts to queue a batch of transactions if they are valid,
+// whilst assuming the transaction pool lock is already held.
+func (pool *TxPool) addTxsLocked(txs []*types.Transaction, local bool) error {
 	// Add the batch of transaction, tracking the accepted ones
 	dirty := make(map[common.Address]struct{})
 	for _, tx := range txs {
@@ -748,15 +791,11 @@ func (pool *TxPool) addTxs(txs []*types.Transaction, local bool) error {
 	}
 	// Only reprocess the internal state if something was actually added
 	if len(dirty) > 0 {
-		state, err := pool.blockChain.State()
-		if err != nil {
-			return err
-		}
 		addrs := make([]common.Address, 0, len(dirty))
 		for addr, _ := range dirty {
 			addrs = append(addrs, addr)
 		}
-		pool.promoteExecutables(state, addrs)
+		pool.promoteExecutables(addrs)
 	}
 	return nil
 }
@@ -770,24 +809,6 @@ func (pool *TxPool) Get(hash common.Hash) *types.Transaction {
 	return pool.all[hash]
 }
 
-// Remove removes the transaction with the given hash from the pool.
-func (pool *TxPool) Remove(hash common.Hash) {
-	pool.mu.Lock()
-	defer pool.mu.Unlock()
-
-	pool.removeTx(hash)
-}
-
-// RemoveBatch removes all given transactions from the pool.
-func (pool *TxPool) RemoveBatch(txs types.Transactions) {
-	pool.mu.Lock()
-	defer pool.mu.Unlock()
-
-	for _, tx := range txs {
-		pool.removeTx(tx.Hash())
-	}
-}
-
 // removeTx removes a single transaction from the queue, moving all subsequent
 // transactions back to the future queue.
 func (pool *TxPool) removeTx(hash common.Hash) {
@@ -834,9 +855,7 @@ func (pool *TxPool) removeTx(hash common.Hash) {
 // promoteExecutables moves transactions that have become processable from the
 // future queue to the set of pending transactions. During this process, all
 // invalidated transactions (low nonce, low balance) are deleted.
-func (pool *TxPool) promoteExecutables(state *state.StateDB, accounts []common.Address) {
-	gaslimit := pool.blockChain.GasLimit()
-
+func (pool *TxPool) promoteExecutables(accounts []common.Address) {
 	// Gather all the accounts potentially needing updates
 	if accounts == nil {
 		accounts = make([]common.Address, 0, len(pool.queue))
@@ -851,14 +870,14 @@ func (pool *TxPool) promoteExecutables(state *state.StateDB, accounts []common.A
 			continue // Just in case someone calls with a non existing account
 		}
 		// Drop all transactions that are deemed too old (low nonce)
-		for _, tx := range list.Forward(state.GetNonce(addr)) {
+		for _, tx := range list.Forward(pool.currentState.GetNonce(addr)) {
 			hash := tx.Hash()
 			log.Trace("Removed old queued transaction", "hash", hash)
 			delete(pool.all, hash)
 			pool.priced.Removed()
 		}
 		// Drop all transactions that are too costly (low balance or out of gas)
-		drops, _ := list.Filter(state.GetBalance(addr), gaslimit)
+		drops, _ := list.Filter(pool.currentState.GetBalance(addr), pool.currentMaxGas)
 		for _, tx := range drops {
 			hash := tx.Hash()
 			log.Trace("Removed unpayable queued transaction", "hash", hash)
@@ -1003,12 +1022,10 @@ func (pool *TxPool) promoteExecutables(state *state.StateDB, accounts []common.A
 // demoteUnexecutables removes invalid and processed transactions from the pools
 // executable/pending queue and any subsequent transactions that become unexecutable
 // are moved back into the future queue.
-func (pool *TxPool) demoteUnexecutables(state *state.StateDB) {
-	gaslimit := pool.blockChain.GasLimit()
-
+func (pool *TxPool) demoteUnexecutables() {
 	// Iterate over all accounts and demote any non-executable transactions
 	for addr, list := range pool.pending {
-		nonce := state.GetNonce(addr)
+		nonce := pool.currentState.GetNonce(addr)
 
 		// Drop all transactions that are deemed too old (low nonce)
 		for _, tx := range list.Forward(nonce) {
@@ -1018,7 +1035,7 @@ func (pool *TxPool) demoteUnexecutables(state *state.StateDB) {
 			pool.priced.Removed()
 		}
 		// Drop all transactions that are too costly (low balance or out of gas), and queue any invalids back for later
-		drops, invalids := list.Filter(state.GetBalance(addr), gaslimit)
+		drops, invalids := list.Filter(pool.currentState.GetBalance(addr), pool.currentMaxGas)
 		for _, tx := range drops {
 			hash := tx.Hash()
 			log.Trace("Removed unpayable pending transaction", "hash", hash)
@@ -1031,6 +1048,14 @@ func (pool *TxPool) demoteUnexecutables(state *state.StateDB) {
 			log.Trace("Demoting pending transaction", "hash", hash)
 			pool.enqueueTx(hash, tx)
 		}
+		// If there's a gap in front, warn (should never happen) and postpone all transactions
+		if list.Len() > 0 && list.txs.Get(nonce) == nil {
+			for _, tx := range list.Cap(0) {
+				hash := tx.Hash()
+				log.Error("Demoting invalidated transaction", "hash", hash)
+				pool.enqueueTx(hash, tx)
+			}
+		}
 		// Delete the entire queue entry if it became empty.
 		if list.Empty() {
 			delete(pool.pending, addr)