Issue 4167 - getSelectorsForDomain criteria + keys

lib/elemHide.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2016 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 25 matching lines @@
 var keyByFilter = Object.create(null);
 
 /**
  * Nested lookup table, filter (or false if inactive) by filter key by domain.
  * (Only contains filters that aren't unconditionally matched for all domains.)
  * @type Object
  */
 var filtersByDomain = Object.create(null);
 
 /**
- * Lookup table, filters key by selector. (Only contains filters that have a
+ * Lookup table, filter keys by selector. (Only contains filters that have a
  * selector that is unconditionally matched for all domains.)
  */
-var filterKeyBySelector = Object.create(null);
-
-/**
- * This array caches the keys of filterKeyBySelector table (selectors which
+var filterKeysBySelector = Object.create(null);
+
+/**
+ * This array caches the keys of filterKeysBySelector table (selectors which
  * unconditionally apply on all domains). It will be null if the cache needs to
  * be rebuilt.
  */
 var unconditionalSelectors = null;
 
 /**
- * This array caches the values of filterKeyBySelector table (filterIds for
+ * This array caches the values of filterKeysBySelector table (filterIds for
  * selectors which unconditionally apply on all domains). It will be null if the
- * cache needs to be rebuilt.
+ * cache needs to be rebuilt. Note: Only the first filter key for each selector
+ * is cached.
  */
 var unconditionalFilterKeys = null;
 
 /**
  * Object to be used instead when a filter has a blank domains property.
  */
 var defaultDomains = Object.create(null);
 defaultDomains[""] = true;
 
 /**
@@ skipping 15 matching lines @@
 var ElemHide = exports.ElemHide =
 {
   /**
    * Removes all known filters
    */
   clear: function()
   {
     filterByKey = [];
     keyByFilter = Object.create(null);
     filtersByDomain = Object.create(null);
-    filterKeyBySelector = Object.create(null);
+    filterKeysBySelector = Object.create(null);
     unconditionalSelectors = unconditionalFilterKeys = null;
     knownExceptions = Object.create(null);
     exceptions = Object.create(null);
     FilterNotifier.emit("elemhideupdate");
   },
 
   _addToFiltersByDomain: function(key, filter)
   {
     let domains = filter.domains || defaultDomains;
     for (let domain in domains)
@@ skipping 21 matching lines @@
         return;
 
       let selector = filter.selector;
       if (!(selector in exceptions))
         exceptions[selector] = [];
       exceptions[selector].push(filter);
 
       // If this is the first exception for a previously unconditionally
       // applied element hiding selector we need to take care to update the
       // lookups.
-      let filterKey = filterKeyBySelector[selector];
-      if (filterKey)
+      let filterKeys = filterKeysBySelector[selector];
+      if (filterKeys)
       {
-        this._addToFiltersByDomain(filterKey, filterByKey[filterKey]);
-        delete filterKeyBySelector[selector];
+        for (let filterKey of filterKeys)
+          this._addToFiltersByDomain(filterKey, filterByKey[filterKey]);
+        delete filterKeysBySelector[selector];
         unconditionalSelectors = unconditionalFilterKeys = null;
       }
 
       knownExceptions[filter.text] = true;
     }
     else
     {
       if (filter.text in keyByFilter)
         return;
 
       let key = filterByKey.push(filter) - 1;
       keyByFilter[filter.text] = key;
 
       if (!(filter.domains || filter.selector in exceptions))
       {
         // The new filter's selector is unconditionally applied to all domains
-        filterKeyBySelector[filter.selector] = key;
-        unconditionalSelectors = unconditionalFilterKeys = null;
+        let filterKeys = filterKeysBySelector[filter.selector];
+        if (filterKeys)
+        {
+          filterKeys.push(key);
+        }
+        else
+        {
+          filterKeysBySelector[filter.selector] = [key];
+          unconditionalSelectors = unconditionalFilterKeys = null;
+        }
       }
       else
       {
         // The new filter's selector only applies to some domains
         this._addToFiltersByDomain(key, filter);
       }
     }
 
     FilterNotifier.emit("elemhideupdate");
   },
 
+  _removeFilterKey: function(key, filter)
+  {
+    let filterKeys = filterKeysBySelector[filter.selector];
+    if (filterKeys)
+    {
+      let index = filterKeys.indexOf(key);
+      if (index >= 0)
+      {
+        if (filterKeys.length > 1)
+        {
+          filterKeys.splice(index, 1);
+          if (index == 0)
+            unconditionalFilterKeys = null;
+        }
+        else
+        {
+          delete filterKeysBySelector[filter.selector];
+          unconditionalSelectors = unconditionalFilterKeys = null;
+        }
+        return;
+      }
+    }
+
+    // We haven't found this filter in unconditional filters, look in
+    // filtersByDomain.
+    let domains = filter.domains || defaultDomains;
+    for (let domain in domains)
+    {
+      let filters = filtersByDomain[domain];
+      if (filters)
+        delete filters[key];
+    }
+  },
+
   /**
    * Removes an element hiding filter
    * @param {ElemHideFilter} filter
    */
   remove: function(filter)
   {
     if (filter instanceof ElemHideException)
     {
       if (!(filter.text in knownExceptions))
         return;
 
       let list = exceptions[filter.selector];
       let index = list.indexOf(filter);
       if (index >= 0)
         list.splice(index, 1);
       delete knownExceptions[filter.text];
     }
     else
     {
       if (!(filter.text in keyByFilter))
         return;
 
       let key = keyByFilter[filter.text];
       delete filterByKey[key];
       delete keyByFilter[filter.text];
-
-      if (filter.selector in filterKeyBySelector)
-      {
-        delete filterKeyBySelector[filter.selector];
-        unconditionalSelectors = unconditionalFilterKeys = null;
-      }
-      else
-      {
-        let domains = filter.domains || defaultDomains;
-        for (let domain in domains)
-        {
-          let filters = filtersByDomain[domain];
-          if (filters)
-            delete filters[key];
-        }
-      }
+      this._removeFilterKey(key, filter);
     }
 
     FilterNotifier.emit("elemhideupdate");
   },
 
   /**
    * Checks whether an exception rule is registered for a filter on a particular
    * domain.
    */
   getException: function(/**Filter*/ filter, /**String*/ docDomain) /**ElemHideException*/
@@ skipping 44 matching lines @@
     return domains;
   },
 
   /**
    * Returns a list of selectors that apply on each website unconditionally.
    * @returns {String[]}
    */
   getUnconditionalSelectors: function()
   {
     if (!unconditionalSelectors)
-      unconditionalSelectors = Object.keys(filterKeyBySelector);
+      unconditionalSelectors = Object.keys(filterKeysBySelector);
     return unconditionalSelectors.slice();
   },
 
   /**
    * Returns a list of all selectors active on a particular domain.
    * Returns a list of filterKeys for selectors that apply on each website
    * unconditionally.
    * @returns {Number[]}
    */
   getUnconditionalFilterKeys: function()
   {
     if (!unconditionalFilterKeys)
     {
       let selectors = this.getUnconditionalSelectors();
       unconditionalFilterKeys = [];
       for (let selector of selectors)
-        unconditionalFilterKeys.push(filterKeyBySelector[selector]);
+        unconditionalFilterKeys.push(filterKeysBySelector[selector][0]);
     }
     return unconditionalFilterKeys.slice();
   },
 
-  /**
-   * Returns a list of all selectors active on a particular domain. Optionally
-   * a list of corresponding filter keys for the selectors can be returned too.
-   */
-  getSelectorsForDomain: function(/**String*/ domain, /**Boolean*/ specificOnly,
-                                  /**Boolean*/ noUnconditional,
-                                  /**Boolean*/ provideFilterKeys)
+
+  /**
+   * Constant used by getSelectorsForDomain to return all selectors applying to
+   * a particular hostname.
+   */
+  ALL_MATCHING: 0,
+
+  /**
+   * Constant used by getSelectorsForDomain to exclude selectors which apply to
+   * all websites without exception.
+   */
+  NO_UNCONDITIONAL: 1,
+
+  /**
+   * Constant used by getSelectorsForDomain to return only selectors for filters
+   * which specifically match the given host name.
+   */
+  SPECIFIC_ONLY: 2,
+
+  /**
+   * Determines from the current filter list which selectors should be applied
+   * on a particular host name. Optionally returns the corresponding filter
+   * keys.
+   * @param {String} domain
+   * @param {Number} [criteria]
+   *   One of the following: ElemHide.ALL_MATCHING, ElemHide.NO_UNCONDITIONAL or
+   *                         ElemHide.SPECIFIC_ONLY.
+   * @param {Boolean} [provideFilterKeys]
+   *   If true, the function will return a list of corresponding filter keys in
+   *   addition to selectors.
+   * @returns {string[]|Array.<string[]>}
+   *   List of selectors or an array with two elements (list of selectors and
+   *   list of corresponding keys) if provideFilterKeys is true.
+   */
+  getSelectorsForDomain: function(domain, criteria, provideFilterKeys)
   {
     let filterKeys = [];
     let selectors = [];
-    if (!specificOnly && !noUnconditional)
+
+    if (typeof criteria == "undefined")
+      criteria = ElemHide.ALL_MATCHING;
+    if (criteria < ElemHide.NO_UNCONDITIONAL)
     {
       selectors = this.getUnconditionalSelectors();
       if (provideFilterKeys)
         filterKeys = this.getUnconditionalFilterKeys();
     }
 
+    let specificOnly = (criteria >= ElemHide.SPECIFIC_ONLY);
     let seenFilters = Object.create(null);
     let currentDomain = domain ? domain.toUpperCase() : "";
     while (true)
     {
       if (specificOnly && currentDomain == "")
         break;
 
       let filters = filtersByDomain[currentDomain];
       if (filters)
       {
@@ skipping 19 matching lines @@
       let nextDot = currentDomain.indexOf(".");
       currentDomain = nextDot == -1 ? "" : currentDomain.substr(nextDot + 1);
     }
 
     if (provideFilterKeys)
       return [selectors, filterKeys];
     else
       return selectors;
   }
 };