bugfix: BufGet must make if b is nil

leveldb/db.go

@@ -345,7 +345,7 @@ func (db *DB) get(r []byte, ro *ReadOptions, key []byte) ([]byte, error) {
 
 	defer C.leveldb_get_free_ext(unsafe.Pointer(c))
 
-	if int(C.int(vallen)) > len(r) {
+	if r == nil || int(C.int(vallen)) > len(r) {
 		return C.GoBytes(unsafe.Pointer(value), C.int(vallen)), nil
 	} else {
 		b := slice(unsafe.Pointer(value), int(C.int(vallen)))

leveldb/iterator.go

@@ -98,7 +98,7 @@ func (it *Iterator) BufKey(b []byte) []byte {
 	if k == nil {
 		return nil
 	}
-	if len(k) > len(b) {
+	if b == nil || len(k) > len(b) {
 		b = make([]byte, len(k))
 	}
 
@@ -112,7 +112,7 @@ func (it *Iterator) BufValue(b []byte) []byte {
 	if v == nil {
 		return nil
 	}
-	if len(v) > len(b) {
+	if b == nil || len(v) > len(b) {
 		b = make([]byte, len(v))
 	}
 
@@ -208,6 +208,14 @@ func (it *RangeLimitIterator) RawValue() []byte {
 	return it.it.RawValue()
 }
 
+func (it *RangeLimitIterator) BufKey(b []byte) []byte {
+	return it.it.BufKey(b)
+}
+
+func (it *RangeLimitIterator) BufValue(b []byte) []byte {
+	return it.it.BufValue(b)
+}
+
 func (it *RangeLimitIterator) Valid() bool {
 	if it.l.Offset < 0 {
 		return false