Merge cf6f93293a into 881bdc289f

trie/hasher.go

@@ -85,11 +85,13 @@ func (h *hasher) hash(n node, db DatabaseWriter, force bool) (node, node, error)
 		cn.flags.hash = cachedHash
 		if db != nil {
 			cn.flags.dirty = false
+			cn.flags.new = false
 		}
 	case *fullNode:
 		cn.flags.hash = cachedHash
 		if db != nil {
 			cn.flags.dirty = false
+			cn.flags.new = false
 		}
 	}
 	return hashed, cached, nil

trie/node.go

@@ -60,6 +60,7 @@ type nodeFlag struct {
 	hash  hashNode // cached hash of the node (may be nil)
 	gen   uint16   // cache generation counter
 	dirty bool     // whether the node has changes that must be written to the database
+	new   bool     // whether the node was allocated in the current generation
 }
 
 // canUnload tells whether a node can be unloaded.
@@ -138,7 +139,7 @@ func decodeShort(hash, buf, elems []byte, cachegen uint16) (node, error) {
 	if err != nil {
 		return nil, err
 	}
-	flag := nodeFlag{hash: hash, gen: cachegen}
+	flag := nodeFlag{hash: hash, gen: cachegen, new: true}
 	key := compactDecode(kbuf)
 	if key[len(key)-1] == 16 {
 		// value node
@@ -156,7 +157,7 @@ func decodeShort(hash, buf, elems []byte, cachegen uint16) (node, error) {
 }
 
 func decodeFull(hash, buf, elems []byte, cachegen uint16) (*fullNode, error) {
-	n := &fullNode{flags: nodeFlag{hash: hash, gen: cachegen}}
+	n := &fullNode{flags: nodeFlag{hash: hash, gen: cachegen, new: true}}
 	for i := 0; i < 16; i++ {
 		cld, rest, err := decodeRef(elems, cachegen)
 		if err != nil {

trie/trie.go

@@ -98,7 +98,7 @@ func (t *Trie) SetCacheLimit(l uint16) {
 
 // newFlag returns the cache flag value for a newly created node.
 func (t *Trie) newFlag() nodeFlag {
-	return nodeFlag{dirty: true, gen: t.cachegen}
+	return nodeFlag{new: true, dirty: true, gen: t.cachegen}
 }
 
 // New creates a trie with an existing root node from db.
@@ -142,46 +142,52 @@ func (t *Trie) Get(key []byte) []byte {
 // If a node was not found in the database, a MissingNodeError is returned.
 func (t *Trie) TryGet(key []byte) ([]byte, error) {
 	key = compactHexDecode(key)
-	value, newroot, didResolve, err := t.tryGet(t.root, key, 0)
-	if err == nil && didResolve {
+	value, newroot, err := t.tryGet(t.root, key, 0)
+	if err == nil {
 		t.root = newroot
 	}
 	return value, err
 }
 
-func (t *Trie) tryGet(origNode node, key []byte, pos int) (value []byte, newnode node, didResolve bool, err error) {
+func (t *Trie) tryGet(origNode node, key []byte, pos int) (value []byte, newnode node, err error) {
 	switch n := (origNode).(type) {
 	case nil:
-		return nil, nil, false, nil
+		return nil, nil, nil
 	case valueNode:
-		return n, n, false, nil
+		return n, n, nil
 	case *shortNode:
 		if len(key)-pos < len(n.Key) || !bytes.Equal(n.Key, key[pos:pos+len(n.Key)]) {
 			// key not found in trie
-			return nil, n, false, nil
+			return nil, n, nil
 		}
-		value, newnode, didResolve, err = t.tryGet(n.Val, key, pos+len(n.Key))
-		if err == nil && didResolve {
+		value, newnode, err = t.tryGet(n.Val, key, pos+len(n.Key))
+		if err == nil {
+			if !n.flags.new {
 				n = n.copy()
-			n.Val = newnode
+				n.flags.new = true
+			}
 			n.flags.gen = t.cachegen
+			n.Val = newnode
 		}
-		return value, n, didResolve, err
+		return value, n, err
 	case *fullNode:
-		value, newnode, didResolve, err = t.tryGet(n.Children[key[pos]], key, pos+1)
-		if err == nil && didResolve {
+		value, newnode, err = t.tryGet(n.Children[key[pos]], key, pos+1)
+		if err == nil {
+			if !n.flags.new {
 				n = n.copy()
+				n.flags.new = true
+			}
 			n.flags.gen = t.cachegen
 			n.Children[key[pos]] = newnode
 		}
-		return value, n, didResolve, err
+		return value, n, err
 	case hashNode:
 		child, err := t.resolveHash(n, key[:pos], key[pos:])
 		if err != nil {
-			return nil, n, true, err
+			return nil, n, err
 		}
-		value, newnode, _, err := t.tryGet(child, key, pos)
-		return value, newnode, true, err
+		value, newnode, err := t.tryGet(child, key, pos)
+		return value, newnode, err
 	default:
 		panic(fmt.Sprintf("%T: invalid node: %v", origNode, origNode))
 	}

trie/trie_test.go

@@ -329,8 +329,7 @@ func TestCacheUnload(t *testing.T) {
 	root, _ := trie.Commit()
 
 	// Commit the trie repeatedly and access key1.
-	// The branch containing it is loaded from DB exactly two times:
-	// in the 0th and 6th iteration.
+	// The branch containing it is loaded from DB exactly once.
 	db := &countingDB{Database: trie.db, gets: make(map[string]int)}
 	trie, _ = New(root, db)
 	trie.SetCacheLimit(5)
@@ -339,10 +338,10 @@ func TestCacheUnload(t *testing.T) {
 		trie.Commit()
 	}
 
-	// Check that it got loaded two times.
+	// Check that it got loaded once.
 	for dbkey, count := range db.gets {
-		if count != 2 {
-			t.Errorf("db key %x loaded %d times, want %d times", []byte(dbkey), count, 2)
+		if count != 1 {
+			t.Errorf("db key %x loaded %d times, want %d times", []byte(dbkey), count, 1)
 		}
 	}
 }