[adblockpluscore] Issue 4825 - Let ElemHideEmulation associate selector and filter when calling add…

chrome/content/elemHideEmulation.js

Index: chrome/content/elemHideEmulation.js
diff --git a/chrome/content/elemHideEmulation.js b/chrome/content/elemHideEmulation.js
index 95a4c5d4ba314ce0c5697c626e52e62edbde574c..3ea1ab7079058edc555b3c31b4ac6bb81c2912e1 100644
--- a/chrome/content/elemHideEmulation.js
+++ b/chrome/content/elemHideEmulation.js
@@ -73,7 +73,7 @@ ElemHideEmulation.prototype = {
     }
   },
 
-  findSelectors: function(stylesheet, selectors, filters)
+  findSelectors: function(stylesheet, filters)
   {
     // Explicitly ignore third-party stylesheets to ensure consistent behavior
     // between Firefox and Chrome.
@@ -97,9 +97,14 @@ ElemHideEmulation.prototype = {
         if (pattern.regexp.test(style))
         {
           var subSelectors = splitSelector(rule.selectorText);
+          var selectors = [];
+
           for (var k = 0; k < subSelectors.length; k++)
             selectors.push(pattern.prefix + subSelectors[k] + pattern.suffix);
-          filters[pattern.text] = true;
+
+          if (!filters.has(pattern.text))
+            filters.set(pattern.text, []);
+          Array.prototype.push.apply(filters.get(pattern.text), selectors);

[Sebastian Noack, 2017/02/07 12:35:59]

Creating a temporary array, just to merge it with another array, seems
unnecessary, here. How about following approach?

  let selectors = filters.get(pattern.text);
  if (!selectors)
  {
    selectors = [];
    filters.set(pattern.text, selectors);
  }

  for (let subSelector of subSelectors)
    selectors.push(pattern.prefix + subSelector + pattern.suffix);

Note that while on it, I also replaced the for(;;) loop with a for..of loop, for
simplicity and compliance with our coding practices for modern code. You might
want to do the same below.

And by the way, if you should ever need to pass variable arguments to a
function, in modern code, be aware of the rest operator; i.e. `o.f(...vargs)` is
equivalent to `f.apply(o, vargs)`, but much more readable.

[wspee, 2017/02/07 14:15:08]

Done.

         }
       }
     }
@@ -107,11 +112,10 @@ ElemHideEmulation.prototype = {
 
   addSelectors: function(stylesheets)
   {
-    var selectors = [];
-    var filters = {};
+    var filters = new Map();
     for (var i = 0; i < stylesheets.length; i++)
-      this.findSelectors(stylesheets[i], selectors, filters);
-    this.addSelectorsFunc(selectors, Object.keys(filters));
+      this.findSelectors(stylesheets[i], filters);
+    this.addSelectorsFunc(filters);
   },
 
   onLoad: function(event)