From 16d4a7b5b6f549199da96badcc6eba899b8c15fc Mon Sep 17 00:00:00 2001
From: Vinko Kasljevic <vinko.kasljevic@memgraph.io>
Date: Tue, 7 May 2019 14:44:24 +0200
Subject: [PATCH] Add nullptr check in LruList

Summary:
Clang-analyzer-core found NullDereference issue in LruList. I don't see
how that can occur, but as a precaution I'll add a CHECK.

Reviewers: msantl, ipaljak

Reviewed By: msantl

Subscribers: pullbot

Differential Revision: https://phabricator.memgraph.io/D2015
---
 src/utils/cache.hpp | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/utils/cache.hpp b/src/utils/cache.hpp
index 53bbee69d..41009d203 100644
--- a/src/utils/cache.hpp
+++ b/src/utils/cache.hpp
@@ -31,6 +31,8 @@ class LruList {
     if (!front_ && !rear_) {
       front_ = rear_ = page;
     } else {
+      CHECK(front_ != nullptr && rear_ != nullptr)
+        << "Both front_ and rear_ must be valid";
       page->next = front_;
       front_->prev = page;
       front_ = page;
@@ -39,6 +41,8 @@ class LruList {
   }
 
   void MovePageToHead(Node<TKey, TValue> *page) {
+    CHECK(front_ != nullptr && rear_ != nullptr)
+      << "Both front_ and rear_ must be valid";
     if (page == front_) {
       return;
     }
@@ -55,6 +59,7 @@ class LruList {
     front_->prev = page;
     front_ = page;
   }
+
   void RemoveRearPage() {
     if (IsEmpty()) {
       return;