Issue 6923 - Only parse metadata from special comments at the top of the file

lib/synchronizer.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-present eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 142 matching lines @@
       return errorCallback("synchronize_invalid_data");
     let minVersion = headerMatch[1];
 
     let params = {
       redirect: null,
       homepage: null,
       title: null,
       version: null,
       expires: null
     };
-    for (let i = 0; i < lines.length; i++)
+    for (let i = 1; i < lines.length; i++)
     {
-      let match = /^\s*!\s*(\w+)\s*:\s*(.*)/.exec(lines[i]);
-      if (match)
+      let match = /^\s*!\s*(?:(\w+)\s*:\s*(.*)|\S)/.exec(lines[i]);
+      if (!match)
+        break;
+
+      if (typeof match[1] != "undefined")
       {
         let keyword = match[1].toLowerCase();
-        let value = match[2];
-        if (keyword in params)
+        if (params.hasOwnProperty(keyword))
         {
-          params[keyword] = value;
+          params[keyword] = match[2];
           lines.splice(i--, 1);
         }
       }
     }
 
     if (params.redirect)
       return redirectCallback(params.redirect);
 
     // Handle redirects
     let subscription = Subscription.fromURL(downloadable.redirectURL ||
@@ skipping 150 matching lines @@
               subscription.filters.map(f => f.text).join("\n");
             redirectCallback("data:text/plain," + encodeURIComponent(data));
           }
         }, false);
         request.send(null);
       }
     }
   }
 };
 Synchronizer.init();