Add tree.AddBatch (using db.Tx)

tree.go

@@ -58,7 +58,7 @@ func NewTree(storage db.Storage, maxLevels int, hash HashFunction) (*Tree, error
 	t := Tree{db: storage, maxLevels: maxLevels, hashFunction: hash}
 
 	t.updateAccessTime()
-	root, err := t.db.Get(dbKeyRoot)
+	root, err := t.dbGet(nil, dbKeyRoot)
 	if err == db.ErrNotFound {
 		// store new root 0
 		tx, err := t.db.NewTx()
@@ -66,12 +66,10 @@ func NewTree(storage db.Storage, maxLevels int, hash HashFunction) (*Tree, error
 			return nil, err
 		}
 		t.root = make([]byte, t.hashFunction.Len()) // empty
-		err = tx.Put(dbKeyRoot, t.root)
-		if err != nil {
+		if err = tx.Put(dbKeyRoot, t.root); err != nil {
 			return nil, err
 		}
-		err = tx.Commit()
-		if err != nil {
+		if err = tx.Commit(); err != nil {
 			return nil, err
 		}
 		return &t, err
@@ -96,17 +94,59 @@ func (t *Tree) Root() []byte {
 	return t.root
 }
 
-// AddBatch adds a batch of key-values to the Tree. This method is optimized to
-// do some internal parallelization. Returns an array containing the indexes of
-// the keys failed to add.
+// AddBatch adds a batch of key-values to the Tree. This method will be
+// optimized to do some internal parallelization. Returns an array containing
+// the indexes of the keys failed to add.
 func (t *Tree) AddBatch(keys, values [][]byte) ([]int, error) {
-	return nil, fmt.Errorf("unimplemented")
+	if len(keys) != len(values) {
+		return nil, fmt.Errorf("len(keys)!=len(values) (%d!=%d)",
+			len(keys), len(values))
+	}
+
+	tx, err := t.db.NewTx()
+	if err != nil {
+		return nil, err
+	}
+
+	var indexes []int
+	for i := 0; i < len(keys); i++ {
+		tx, err = t.add(tx, keys[i], values[i])
+		if err != nil {
+			indexes = append(indexes, i)
+		}
+	}
+	// store root to db
+	if err := tx.Put(dbKeyRoot, t.root); err != nil {
+		return indexes, err
+	}
+
+	if err := tx.Commit(); err != nil {
+		return nil, err
+	}
+	return indexes, nil
 }
 
-// Add inserts the key-value into the Tree.
-// If the inputs come from a *big.Int, is expected that are represented by a
-// Little-Endian byte array (for circom compatibility).
+// Add inserts the key-value into the Tree.  If the inputs come from a *big.Int,
+// is expected that are represented by a Little-Endian byte array (for circom
+// compatibility).
 func (t *Tree) Add(k, v []byte) error {
+	tx, err := t.db.NewTx()
+	if err != nil {
+		return err
+	}
+
+	tx, err = t.add(tx, k, v)
+	if err != nil {
+		return err
+	}
+	// store root to db
+	if err := tx.Put(dbKeyRoot, t.root); err != nil {
+		return err
+	}
+	return tx.Commit()
+}
+
+func (t *Tree) add(tx db.Tx, k, v []byte) (db.Tx, error) {
 	// TODO check validity of key & value (for the Tree.HashFunction type)
 
 	keyPath := make([]byte, t.hashFunction.Len())
@@ -115,41 +155,37 @@ func (t *Tree) Add(k, v []byte) error {
 	path := getPath(t.maxLevels, keyPath)
 	// go down to the leaf
 	var siblings [][]byte
-	_, _, siblings, err := t.down(k, t.root, siblings, path, 0, false)
+	_, _, siblings, err := t.down(tx, k, t.root, siblings, path, 0, false)
 	if err != nil {
-		return err
+		return tx, err
 	}
 
 	leafKey, leafValue, err := newLeafValue(t.hashFunction, k, v)
 	if err != nil {
-		return err
+		return tx, err
 	}
 
-	tx, err := t.db.NewTx()
-	if err != nil {
-		return err
-	}
 	if err := tx.Put(leafKey, leafValue); err != nil {
-		return err
+		return tx, err
 	}
 
 	// go up to the root
 	if len(siblings) == 0 {
 		t.root = leafKey
-		return tx.Commit()
+		return tx, nil
 	}
 	root, err := t.up(tx, leafKey, siblings, path, len(siblings)-1)
 	if err != nil {
-		return err
+		return tx, err
 	}
 
 	t.root = root
-	// store root to db
-	return tx.Commit()
+	return tx, nil
 }
 
 // down goes down to the leaf recursively
-func (t *Tree) down(newKey, currKey []byte, siblings [][]byte, path []bool, l int, getLeaf bool) (
+func (t *Tree) down(tx db.Tx, newKey, currKey []byte, siblings [][]byte,
+	path []bool, l int, getLeaf bool) (
 	[]byte, []byte, [][]byte, error) {
 	if l > t.maxLevels-1 {
 		return nil, nil, nil, fmt.Errorf("max level")
@@ -161,7 +197,7 @@ func (t *Tree) down(newKey, currKey []byte, siblings [][]byte, path []bool, l in
 		// empty value
 		return currKey, emptyValue, siblings, nil
 	}
-	currValue, err = t.db.Get(currKey)
+	currValue, err = t.dbGet(tx, currKey)
 	if err != nil {
 		return nil, nil, nil, err
 	}
@@ -204,12 +240,12 @@ func (t *Tree) down(newKey, currKey []byte, siblings [][]byte, path []bool, l in
 			// right
 			lChild, rChild := readIntermediateChilds(currValue)
 			siblings = append(siblings, lChild)
-			return t.down(newKey, rChild, siblings, path, l+1, getLeaf)
+			return t.down(tx, newKey, rChild, siblings, path, l+1, getLeaf)
 		}
 		// left
 		lChild, rChild := readIntermediateChilds(currValue)
 		siblings = append(siblings, rChild)
-		return t.down(newKey, lChild, siblings, path, l+1, getLeaf)
+		return t.down(tx, newKey, lChild, siblings, path, l+1, getLeaf)
 	default:
 		return nil, nil, nil, fmt.Errorf("invalid value")
 	}
@@ -225,7 +261,7 @@ func (t *Tree) downVirtually(siblings [][]byte, oldKey, newKey []byte, oldPath,
 	}
 
 	if oldPath[l] == newPath[l] {
-		emptyKey := make([]byte, t.hashFunction.Len()) // empty
+		emptyKey := make([]byte, t.hashFunction.Len())
 		siblings = append(siblings, emptyKey)
 
 		siblings, err = t.downVirtually(siblings, oldKey, newKey, oldPath, newPath, l+1)
@@ -256,8 +292,7 @@ func (t *Tree) up(tx db.Tx, key []byte, siblings [][]byte, path []bool, l int) (
 		}
 	}
 	// store k-v to db
-	err = tx.Put(k, v)
-	if err != nil {
+	if err = tx.Put(k, v); err != nil {
 		return nil, err
 	}
 
@@ -343,7 +378,7 @@ func (t *Tree) GenProof(k []byte) ([]byte, error) {
 	path := getPath(t.maxLevels, keyPath)
 	// go down to the leaf
 	var siblings [][]byte
-	_, value, siblings, err := t.down(k, t.root, siblings, path, 0, true)
+	_, value, siblings, err := t.down(nil, k, t.root, siblings, path, 0, true)
 	if err != nil {
 		return nil, err
 	}
@@ -440,7 +475,7 @@ func (t *Tree) Get(k []byte) ([]byte, []byte, error) {
 	path := getPath(t.maxLevels, keyPath)
 	// go down to the leaf
 	var siblings [][]byte
-	_, value, _, err := t.down(k, t.root, siblings, path, 0, true)
+	_, value, _, err := t.down(nil, k, t.root, siblings, path, 0, true)
 	if err != nil {
 		return nil, nil, err
 	}
@@ -487,3 +522,14 @@ func CheckProof(hashFunc HashFunction, k, v, root, packedSiblings []byte) (bool,
 	}
 	return false, nil
 }
+
+func (t *Tree) dbGet(tx db.Tx, k []byte) ([]byte, error) {
+	v, err := t.db.Get(k)
+	if err == nil {
+		return v, nil
+	}
+	if tx != nil {
+		return tx.Get(k)
+	}
+	return nil, db.ErrNotFound
+}