core: abstract out a sorted transaction hash map

1 files changed, 203 insertions, 192 deletions

diff --git a/core/tx_list.go b/core/tx_list.go
index 8c69331cc..c3ddf3148 100644
--- a/core/tx_list.go
+++ b/core/tx_list.go
@@ -45,20 +45,182 @@ func (h *nonceHeap) Pop() interface{} {
 	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
-	items  map[uint64]*types.Transaction // Hash map storing the transaction data
-	cache  types.Transactions            // Cache of the transactions already sorted
-
-	first uint64     // Nonce of the lowest stored transaction (strict mode)
-	last  uint64     // Nonce of the highest stored transaction (strict mode)
-	index *nonceHeap // Heap of nonces of all the stored transactions (non-strict mode)
-
-	costcap *big.Int // Price of the highest costing transaction (reset only if exceeds balance)
+	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,
@@ -66,9 +228,7 @@ type txList struct {
 func newTxList(strict bool) *txList {
 	return &txList{
 		strict:  strict,
-		items:   make(map[uint64]*types.Transaction),
-		first:   math.MaxUint64,
-		index:   &nonceHeap{},
+		txs:     newTxSortedMap(),
 		costcap: new(big.Int),
 	}
 }
@@ -76,36 +236,19 @@ func newTxList(strict bool) *txList {
 // Add tries to insert a new transaction into the list, returning whether the
 // transaction was accepted, and if yes, any previous transaction it replaced.
 //
-// In case of strict lists (contiguous nonces) the nonce boundaries are updated
-// appropriately with the new transaction. Otherwise (gapped nonces) the heap of
-// nonces is expanded with the new transaction.
+// 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 an existing transaction is better, discard new one
-	nonce := tx.Nonce()
-
-	old, ok := l.items[nonce]
-	if ok && old.GasPrice().Cmp(tx.GasPrice()) >= 0 {
+	// 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 insert the transaction and replace any previous one
-	l.items[nonce] = tx
+	// 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
 	}
-	if l.strict {
-		// In strict mode, maintain the nonce sequence boundaries
-		if nonce < l.first {
-			l.first = nonce
-		}
-		if nonce > l.last {
-			l.last = nonce
-		}
-	} else {
-		// In gapped mode, maintain the nonce heap
-		heap.Push(l.index, nonce)
-	}
-	l.cache = nil
-
 	return true, old
 }
 
@@ -113,31 +256,7 @@ func (l *txList) Add(tx *types.Transaction) (bool, *types.Transaction) {
 // provided threshold. Every removed transaction is returned for any post-removal
 // maintenance.
 func (l *txList) Forward(threshold uint64) types.Transactions {
-	var removed types.Transactions
-
-	if l.strict {
-		// In strict mode, push the lowest nonce forward to the threshold
-		for l.first < threshold {
-			if tx, ok := l.items[l.first]; ok {
-				removed = append(removed, tx)
-			}
-			delete(l.items, l.first)
-			l.first++
-		}
-		if l.first > l.last {
-			l.last = l.first
-		}
-	} else {
-		// In gapped mode, pop off heap items until the threshold is reached
-		for l.index.Len() > 0 && (*l.index)[0] < threshold {
-			nonce := heap.Pop(l.index).(uint64)
-			removed = append(removed, l.items[nonce])
-			delete(l.items, nonce)
-		}
-	}
-	l.cache = nil
-
-	return removed
+	return l.txs.Forward(threshold)
 }
 
 // Filter removes all transactions from the list with a cost higher than the
@@ -155,110 +274,43 @@ func (l *txList) Filter(threshold *big.Int) (types.Transactions, types.Transacti
 	}
 	l.costcap = new(big.Int).Set(threshold) // Lower the cap to the threshold
 
-	// Gather all the transactions needing deletion
-	var removed types.Transactions
-	for _, tx := range l.items {
-		if cost := tx.Cost(); cost.Cmp(threshold) > 0 {
-			removed = append(removed, tx)
-			delete(l.items, tx.Nonce())
-		}
-	}
-	// Readjust the nonce boundaries/indexes and gather invalidate tranactions
+	// 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 {
-		// In strict mode iterate find the first gap and invalidate everything after it
-		for i := l.first; i <= l.last; i++ {
-			if _, ok := l.items[i]; !ok {
-				// Gap found, invalidate all subsequent transactions
-				for j := i + 1; j <= l.last; j++ {
-					if tx, ok := l.items[j]; ok {
-						invalids = append(invalids, tx)
-						delete(l.items, j)
-					}
-				}
-				// Reduce the highest transaction nonce and return
-				l.last = i - 1
-				break
+	if l.strict && len(removed) > 0 {
+		lowest := uint64(math.MaxUint64)
+		for _, tx := range removed {
+			if nonce := tx.Nonce(); lowest > nonce {
+				lowest = nonce
 			}
 		}
-	} else {
-		// In gapped mode no transactions are invalid, but the heap is ruined
-		l.index = &nonceHeap{}
-		for nonce, _ := range l.items {
-			*l.index = append(*l.index, nonce)
-		}
-		heap.Init(l.index)
+		invalids = l.txs.Filter(func(tx *types.Transaction) bool { return tx.Nonce() > lowest })
 	}
-	l.cache = nil
-
 	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 {
-	// Short circuit if the number of items is under the limit
-	if len(l.items) < threshold {
-		return nil
-	}
-	// Otherwise gather and drop the highest nonce'd transactions
-	var drops types.Transactions
-
-	if l.strict {
-		// In strict mode, just gather top down from last to first
-		for len(l.items) > threshold {
-			if tx, ok := l.items[l.last]; ok {
-				drops = append(drops, tx)
-				delete(l.items, l.last)
-				l.last--
-			}
-		}
-	} else {
-		// In gapped mode it's expensive: we need to sort and drop like that
-		sort.Sort(*l.index)
-		for size := len(l.items); size > threshold; size-- {
-			drops = append(drops, l.items[(*l.index)[size-1]])
-			delete(l.items, (*l.index)[size-1])
-			*l.index = (*l.index)[:size-1]
-		}
-		heap.Init(l.index)
-	}
-	l.cache = nil
-
-	return drops
+	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 _, ok := l.items[nonce]; ok {
-		// Remove the item and invalidate the sorted cache
-		delete(l.items, nonce)
-		l.cache = nil
-
-		// Remove all invalidated transactions (strict mode only!)
-		var invalids types.Transactions
-		if l.strict {
-			invalids = make(types.Transactions, 0, l.last-nonce)
-			for i := nonce + 1; i <= l.last; i++ {
-				invalids = append(invalids, l.items[i])
-				delete(l.items, i)
-			}
-			l.last = nonce - 1
-		} else {
-			// In gapped mode, remove the nonce from the index but honour the heap
-			for i := 0; i < l.index.Len(); i++ {
-				if (*l.index)[i] == nonce {
-					heap.Remove(l.index, i)
-					break
-				}
-			}
-		}
-		return true, invalids
+	if removed := l.txs.Remove(nonce); !removed {
+		return false, nil
 	}
-	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
@@ -269,63 +321,22 @@ func (l *txList) Remove(tx *types.Transaction) (bool, types.Transactions) {
 // 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 {
-	var txs types.Transactions
-	if l.strict {
-		// In strict mode make sure we have valid transaction, return all contiguous
-		if l.first > start {
-			return nil
-		}
-		for {
-			if tx, ok := l.items[l.first]; ok {
-				txs = append(txs, tx)
-				delete(l.items, l.first)
-				l.first++
-				continue
-			}
-			break
-		}
-	} else {
-		// In gapped mode, check the heap start and return all contiguous
-		if l.index.Len() == 0 || (*l.index)[0] > start {
-			return nil
-		}
-		next := (*l.index)[0]
-		for l.index.Len() > 0 && (*l.index)[0] == next {
-			txs = append(txs, l.items[next])
-			delete(l.items, next)
-			heap.Pop(l.index)
-			next++
-		}
-	}
-	l.cache = nil
-
-	return txs
+	return l.txs.Ready(start)
 }
 
 // Len returns the length of the transaction list.
 func (l *txList) Len() int {
-	return len(l.items)
+	return l.txs.Len()
 }
 
 // Empty returns whether the list of transactions is empty or not.
 func (l *txList) Empty() bool {
-	return len(l.items) == 0
+	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 {
-	// If the sorting was not cached yet, create and cache it
-	if l.cache == nil {
-		l.cache = make(types.Transactions, 0, len(l.items))
-		for _, tx := range l.items {
-			l.cache = append(l.cache, tx)
-		}
-		sort.Sort(types.TxByNonce(l.cache))
-	}
-	// Copy the cache to prevent accidental modifications
-	txs := make(types.Transactions, len(l.cache))
-	copy(txs, l.cache)
-	return txs
+	return l.txs.Flatten()
 }