Fixed #4 - Disable rewrite option for all but internal redirect

lib/filterClasses.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 1042 matching lines @@
             break;
           case "collapse":
             collapse = !inverse;
             break;
           case "sitekey":
             if (!value)
               return new InvalidFilter(origText, "filter_unknown_option");
             sitekeys = value.toUpperCase();
             break;
           case "rewrite":
-            if (value == null)
-              return new InvalidFilter(origText, "filter_unknown_option");
+            if (!value.startsWith("abp-resource:"))

[Manish Jethani, 2019/04/15 21:26:37]

`value` could still be `null`?

[hub, 2019/04/16 04:56:24]

Yeah. I'll simplify this now that we are going the removal route.

+              return new InvalidFilter(origText, "filter_invalid_rewrite");
             rewrite = value;
-            if (value.startsWith("abp-resource:"))
-              resourceName = value.substr("abp-resource:".length);
+            resourceName = value.substr("abp-resource:".length);
             break;
           default:
             return new InvalidFilter(origText, "filter_unknown_option");
         }
       }
     }
   }
 
   // For security reasons, never match $rewrite filters
   // against requests that might load any code to be executed.
@@ skipping 141 matching lines @@
   csp: null,
 
   /**
    * Rewrites an URL.
    * @param {string} url the URL to rewrite
    * @return {string} the rewritten URL, or the original in case of failure
    */
   rewriteUrl(url)
   {
     if (this.resourceName)
       return resourceMap.get(this.resourceName) || url;

[Manish Jethani, 2019/04/15 21:26:37]

If `resourceName` is `undefined` or `null` then I'm guessing this automatically
falls back to returning `url`. In that case, we could reduce this function to
just this line.

[hub, 2019/04/16 04:56:23]

Done.

 
-    try
-    {
-      let rewrittenUrl = new URL(url.replace(this.regexp, this.rewrite), url);
-      if (rewrittenUrl.origin == new URL(url).origin)
-        return rewrittenUrl.href;
-    }
-    catch (e)
-    {
-    }
-
     return url;
   }
 });
 
 /**
  * Class for whitelist filters
  * @param {string} text see {@link Filter Filter()}
  * @param {string} regexpSource see {@link RegExpFilter RegExpFilter()}
  * @param {number} [contentType] see {@link RegExpFilter RegExpFilter()}
  * @param {boolean} [matchCase] see {@link RegExpFilter RegExpFilter()}
@@ skipping 195 matching lines @@
 
   /**
    * Script that should be executed
    * @type {string}
    */
   get script()
   {
     return this.body;
   }
 });