From 32e22b3bb6a5f03977e38513b44b33d3cc1d94e5 Mon Sep 17 00:00:00 2001
From: Martin Kobetic <mkobetic@gmail.com>
Date: Tue, 24 Jun 2014 15:30:28 +0000
Subject: [PATCH] add some guards for nil pointers

---
 db.go | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/db.go b/db.go
index 1cfa10f..a37f687 100644
--- a/db.go
+++ b/db.go
@@ -575,8 +575,15 @@ type Stats struct {
 // This is useful when obtaining stats at two different points and time and
 // you need the performance counters that occurred within that time span.
 func (s *Stats) Sub(other *Stats) Stats {
-	var diff Stats = *s
-	diff.TxN = other.TxN - s.TxN
+	var diff Stats
+	if s == nil {
+		return diff
+	}
+	diff = *s
+	if other == nil {
+		return diff
+	}
+	diff.TxN = other.TxN - diff.TxN
 	diff.TxStats = s.TxStats.Sub(&other.TxStats)
 	return diff
 }