Issue 6504 - Remove element hiding emulation code related to style sheets

lib/content/elemHideEmulation.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 587 matching lines @@
   return patterns.some(pattern => pattern.maybeDependsOnAttributes);
 }
 
 function shouldObserveCharacterData(patterns)
 {
   return patterns.some(pattern => pattern.dependsOnCharacterData);
 }
 
 class ElemHideEmulation
 {
   constructor(addSelectorsFunc, hideElemsFunc)

[Sebastian Noack, 2018/09/18 21:29:47]

There are further optimizations and simplifications we can do in
adblockpluschrome if we no longer have to provide an addSelectorFunc. On the
other hand, if you plan on bringing back user stylesheets for emulated element
hiding filters (?), I agree to keep the constructor backwards compatible and not
touch the related code in adblockpluschrome. But then you might want to add a
comment about that here.

[Manish Jethani, 2018/09/19 09:43:32]

At this point I'm really not sure how this is going to go. I would really like
to use style sheets, simply because it's cleaner and harder to mess with (some
documents go into a race condition because they try to unset the inline style
while we try to reset it); but it requires that we maintain the selectors and
keep them up to date, which is a lot of code. For now, I think I'll just leave a
comment in the constructor here. The full discussion about what to do in the
long run can continue on the Trac issue.

   {
     this._filteringInProgress = false;
     this._lastInvocation = -MIN_INVOCATION_INTERVAL;
     this._scheduledProcessing = null;
 
     this.document = document;
-    this.addSelectorsFunc = addSelectorsFunc;
     this.hideElemsFunc = hideElemsFunc;
     this.observer = new MutationObserver(this.observe.bind(this));
   }
 
   isSameOrigin(stylesheet)
   {
     try
     {
       return new URL(stylesheet.href).origin == this.document.location.origin;
     }
@@ skipping 82 matching lines @@
    * @param {function} [done]
    *    Callback to call when done.
    */
   _addSelectors(stylesheets, mutations, done)
   {
     if (testInfo)
       testInfo.lastProcessedElements.clear();
 
     let patterns = filterPatterns(this.patterns, {stylesheets, mutations});
 
-    let selectors = [];
-    let selectorFilters = [];
-
     let elements = [];
     let elementFilters = [];
 
     let cssStyles = [];
 
     // If neither any style sheets nor any DOM mutations have been specified,
     // do full processing.
     if (!stylesheets && !mutations)
       stylesheets = this.document.styleSheets;
 
@@ skipping 45 matching lines @@
     let generator = null;
 
     let processPatterns = () =>
     {
       let cycleStart = performance.now();
 
       if (!pattern)
       {
         if (!patterns.length)
         {
-          if (selectors.length > 0)
-            this.addSelectorsFunc(selectors, selectorFilters);
           if (elements.length > 0)
             this.hideElemsFunc(elements, elementFilters);
           if (typeof done == "function")
             done();
           return;
         }
 
         pattern = patterns.shift();
 
         let evaluationTargets = targets;
@@ skipping 173 matching lines @@
           characterData: shouldObserveCharacterData(this.patterns),
           subtree: true
         }
       );
       this.document.addEventListener("load", this.onLoad.bind(this), true);
     }
   }
 }
 
 exports.ElemHideEmulation = ElemHideEmulation;