Issue 6296 - Handle relative prefix in :-abp-has()

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 117 matching lines @@
 {
   let elements = null;
   try
   {
     elements = all ? subtree.querySelectorAll(selector) :
       subtree.querySelector(selector);
     scopeSupported = true;
   }
   catch (e)
   {
+    // Edge doesn't support ":scope"
     scopeSupported = false;
   }
   return elements;
 }
 
 /**
- * Query selector. If it is relative, will try :scoped.
+ * Query selector. If it is relative, will try :scope.
  * @param {Node} subtree the element to query selector
  * @param {string} selector the selector to query
- * @param {bool} all True to perform querySelectorAll()
- * @returns {Node|NodeList} result of the query. null in case of error.
+ * @param {bool} [all=false] true to perform querySelectorAll()
+ * @returns {?(Node|NodeList)} result of the query. null in case of error.
  */
 function scopedQuerySelector(subtree, selector, all)
 {
-  if (relativeSelectorRegexp.test(selector))
+  if (selector[0] == ">")
   {
     selector = ":scope" + selector;
     if (scopeSupported)

[Manish Jethani, 2018/01/26 08:41:32]

I think since the code in this if block spans multiple lines we're supposed to
add braces.

[hub, 2018/01/26 14:44:45]

Done.

+    {
       return all ? subtree.querySelectorAll(selector) :
         subtree.querySelector(selector);
+    }
     if (scopeSupported == null)
       return tryQuerySelector(subtree, selector, all);
     return null;
   }
   return all ? subtree.querySelectorAll(selector) :
     subtree.querySelector(selector);
 }
 
 function scopedQuerySelectorAll(subtree, selector)
 {
@@ skipping 33 matching lines @@
    * @param {string} prefix the prefix for the selector.
    * @param {Node} subtree the subtree we work on.
    * @param {StringifiedStyle[]} styles the stringified style objects.
    */
   *getSelectors(prefix, subtree, styles)
   {
     yield [prefix + this._selector, subtree];
   }
 };
 
 const incompletePrefixRegexp = /[\s>+~]$/;

[lainverse, 2018/01/30 18:07:28]

Since that other regexp were replaced with string comparison it might be a good
idea to replace this one too:

{
  let u = [];
  let n = 10000000;
  let c = 0;
  let r = /[\s>+~]$/;
  let incomplete = [' ','>','+','~'];
  let isIncompleteArr = c => incomplete.includes(c);
  let isIncompleteStr = c => c == ' ' || c == '>' || c == '+' || c == '~';
  for (let i = 0; i < n; i++)
  {
    if (Math.random() < .1)
      u.push("foo bar" + incomplete[Math.floor(Math.random()*4)]);
    else
      u.push("foo bar");
  }
  let s = performance.now();
  for (let i = 0; i < n; i++)
  {
    //if (r.test(u[i]))
    // if (isIncompleteArr(u[i][u[i].length-1]))
    if (isIncompleteStr(u[i][u[i].length-1]))
      c++;
  }
  let t = (performance.now() - s) | 0;
  console.log(c + " matches found in " + t + "ms");
}

In my tests function isIncompleteArr performs on par with regexp and
isIncompleteStr ~50ms faster both in Firefox and Chrome. Downside: I only check
for normal space character in both functions instead of \s as in the original
regexp. This should work fine if ABP normalize spaces in filters during import.

[Manish Jethani, 2018/01/30 20:23:20]

If we do this then I think that it should be a separate patch.

-const relativeSelectorRegexp = /^[>]/;

[Manish Jethani, 2018/01/26 08:41:32]

Since there's only one character in the group, we could lose the brackets?

[hub, 2018/01/26 14:44:45]

Done.

 
 function HasSelector(selectors)
 {
   this._innerSelectors = selectors;
 }
 
 HasSelector.prototype = {
   requiresHiding: true,
 
   get dependsOnStyles()
@@ skipping 421 matching lines @@
           characterData: true,
           subtree: true
         }
       );
       this.document.addEventListener("load", this.onLoad.bind(this), true);
     }
   }
 };
 
 exports.ElemHideEmulation = ElemHideEmulation;