From 08b05b9fdaa36f605e9f13b4583ed1d5d0d6afb9 Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Sat, 28 Jul 2018 13:19:35 +0200
Subject: [PATCH] Validate the Preferences when fetching them from storage

When updating Preferences using the `set` method, the input is carefully validated. However, no validation is (currently) done when a `BasePreferences` instance is created, which probably isn't that great. Hence this patch that simply ignores, to not unnecessarily break loading of the viewer itself, any invalid Preferences.
---
 web/preferences.js | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/web/preferences.js b/web/preferences.js
index 6d257d55d..a5fa67388 100644
--- a/web/preferences.js
+++ b/web/preferences.js
@@ -60,9 +60,19 @@ class BasePreferences {
 
       this.prefs = Object.assign(Object.create(null), defaults);
       return this._readFromStorage(defaults);
-    }).then((prefObj) => {
-      if (prefObj) {
-        this.prefs = prefObj;
+    }).then((prefs) => {
+      if (!prefs) {
+        return;
+      }
+      for (let name in prefs) {
+        const defaultValue = this.defaults[name], prefValue = prefs[name];
+        // Ignore preferences not present in, or whose types don't match,
+        // the default values.
+        if (defaultValue === undefined ||
+            typeof prefValue !== typeof defaultValue) {
+          continue;
+        }
+        this.prefs[name] = prefValue;
       }
     });
   }