Issue 3364 - Implement JNI bindings for IsDocument/ElemhideWhitelisted

src/org/adblockplus/android/AdblockPlus.java

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2015 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 267 matching lines @@
   {
     if (this.abpEngine.isElemhideEnabled() && this.filteringEnabled)
     {
       if (referrer != null)
       {
         this.referrerMapping.add(url, referrer);
       }
       final List<String> referrerChain = this.referrerMapping.buildReferrerChain(referrer);
       final String[] referrerChainArray = referrerChain.toArray(new String[referrerChain.size()]);
       final List<String> selectors = this.abpEngine.getElementHidingSelectors(url, referrerChainArray);
-      return selectors.toArray(new String[selectors.size()]);
+      // We're returning 'null' when no selectors are available to be consistent
+      // with the previous implementation
+      return selectors.isEmpty() ? null : selectors.toArray(new String[selectors.size()]);
     }
     else
     {
+      /*
+       * This case is still the default for Adblock Plus for Android, as we did not yet
+       * re-enable element hiding but only enhanced/fixed the current implementation.
+       * See: https://issues.adblockplus.org/ticket/3364
+       */
       /* We need to ignore element hiding rules here to work around two bugs:
        * 1. CSS is being injected even when there's an exception rule with $elemhide
        * 2. The injected CSS causes blank pages in Chrome for Android
        *
        * Starting with 1.1.2, we ignored element hiding rules after download anyway, to keep the
        * memory usage down. Doing this with libadblockplus is trickier, but would be the clean
        * solution. */
       return null;
     }
   }
@@ skipping 140 matching lines @@
     }
     catch (final IOException e)
     {
       Log.e(TAG, e.getMessage(), e);
     }
 
     // Set crash handler
     Thread.setDefaultUncaughtExceptionHandler(new CrashHandler(this));
   }
 }