parallel logic for read and write

weed-fs/src/pkg/storage/needle_read_write.go

@@ -90,20 +90,22 @@ func (n *Needle) readNeedleHeader(bytes []byte) {
 	n.Size = util.BytesToUint32(bytes[12:NeedleHeaderSize])
 }
 func (n *Needle) readNeedleDataVersion2(bytes []byte) {
-	index := 0
+	index, lenBytes := 0, len(bytes)
+	if index < lenBytes {
 		n.DataSize = util.BytesToUint32(bytes[index : index+4])
 		index = index + 4
 		n.Data = bytes[index : index+int(n.DataSize)]
 		index = index + int(n.DataSize)
 		n.Flags = bytes[index]
 		index = index + 1
-	if index < len(bytes) {
+	}
+	if index < lenBytes {
 		n.NameSize = uint8(bytes[index])
 		index = index + 1
 		n.Name = bytes[index : index+int(n.NameSize)]
 		index = index + int(n.NameSize)
 	}
-	if index < len(bytes) {
+	if index < lenBytes {
 		n.MimeSize = uint8(bytes[index])
 		index = index + 1
 		n.Mime = bytes[index : index+int(n.MimeSize)]