From 1ef10550b1c5d2730194cbc06d7f790b7472dbf8 Mon Sep 17 00:00:00 2001
From: Ms2ger <Ms2ger@gmail.com>
Date: Wed, 12 Aug 2015 15:10:03 +0200
Subject: [PATCH] Avoid unwrap calls in handle_navigate_msg.

---
 components/compositing/constellation.rs | 28 ++++++++++++++++---------
 1 file changed, 18 insertions(+), 10 deletions(-)

diff --git a/components/compositing/constellation.rs b/components/compositing/constellation.rs
index 50e755eb086..ab5a69b429e 100644
--- a/components/compositing/constellation.rs
+++ b/components/compositing/constellation.rs
@@ -798,20 +798,28 @@ impl<LTF: LayoutTaskFactory, STF: ScriptTaskFactory> Constellation<LTF, STF> {
 
             let next = match direction {
                 NavigationDirection::Forward => {
-                    if frame.next.is_empty() {
-                        debug!("no next page to navigate to");
-                        return;
+                    match frame.next.pop() {
+                        None => {
+                            debug!("no next page to navigate to");
+                            return;
+                        },
+                        Some(next) => {
+                            frame.prev.push(frame.current);
+                            next
+                        },
                     }
-                    frame.prev.push(frame.current);
-                    frame.next.pop().unwrap()
                 }
                 NavigationDirection::Back => {
-                    if frame.prev.is_empty() {
-                        debug!("no previous page to navigate to");
-                        return;
+                    match frame.prev.pop() {
+                        None => {
+                            debug!("no previous page to navigate to");
+                            return;
+                        },
+                        Some(prev) => {
+                            frame.next.push(frame.current);
+                            prev
+                        },
                     }
-                    frame.next.push(frame.current);
-                    frame.prev.pop().unwrap()
                 }
             };
             let prev = frame.current;