Issue 6652 - Implement fast selector lookups for unknown domains

lib/elemHide.js

Index: lib/elemHide.js
===================================================================
--- a/lib/elemHide.js
+++ b/lib/elemHide.js
@@ -113,30 +113,16 @@
       let filters = filtersByDomain.get(domain);
       if (!filters)
         filtersByDomain.set(domain, filters = new Map());
       filters.set(filter, isIncluded);
     }
   }
 }
 
-
-/**
- * Checks whether a filter applies on a domain
- * @param {Filter} filter
- * @param {string} [domain]
- * @param {Set.<Filter>} excludeSet
- * @returns {boolean}
- */
-function doesFilterApply(filter, domain, excludeSet)
-{
-  return (excludeSet.size == 0 || !excludeSet.has(filter)) &&
-         !exports.ElemHide.getException(filter, domain);
-}
-
 /**
  * Returns a list of domain-specific filters matching a domain
  * @param {string} [domain]
  * @returns {Array.<{domain: string, filters: ?Map.<Filter,boolean>}>}
  */
 function getSpecificFiltersForDomain(domain)
 {
   let filtersList = [];
@@ -174,19 +160,24 @@
   for (let i = 0; i < filtersList.length; i++)
   {
     let {filters} = filtersList[i];
     if (filters)
     {
       for (let [filter, isIncluded] of filters)
       {
         if (!isIncluded)
+        {
           excludeSet.add(filter);
-        else if (doesFilterApply(filter, domain, excludeSet))
+        }
+        else if ((excludeSet.size == 0 || !excludeSet.has(filter)) &&
+                  !exports.ElemHide.getException(filter, domain))
+        {
           matches.push(filter.selector);
+        }
       }
     }
   }
 
   return matches;
 }
 
 /**