Issue 4167 - getSelectorsForDomain criteria + keys

lib/elemHide.js

Index: lib/elemHide.js
diff --git a/lib/elemHide.js b/lib/elemHide.js
index 2c81a2324f579247d53eca5eeb6ac459210a937a..c3df791db5e5b8420560e90b796bdfd37c254f5b 100644
--- a/lib/elemHide.js
+++ b/lib/elemHide.js
@@ -36,14 +36,6 @@ var filterByKey = [];
 var keyByFilter = Object.create(null);
 
 /**
- * Indicates whether we are using the getSelectorsForDomain function and
- * therefore mainting the required filtersByDomain, filtersBySelector and
- * unconditionalSelectors lookups. (Will be false for Firefox)
- * @type Boolean
- */
-var usingGetSelectorsForDomain = !("nsIStyleSheetService" in Ci);
-
-/**
  * 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
@@ -51,19 +43,26 @@ var usingGetSelectorsForDomain = !("nsIStyleSheetService" in Ci);
 var filtersByDomain = Object.create(null);
 
 /**
- * Lookup table, filters by selector. (Only contains filters that have a
+ * Lookup table, filters key by selector. (Only contains filters that have a
  * selector that is unconditionally matched for all domains.)
  */
-var filtersBySelector = Object.create(null);
+var filterKeyBySelector = Object.create(null);
 
 /**
- * This array caches the keys of filtersBySelector table (selectors which
+ * This array caches the keys of filterKeyBySelector 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
+ * selectors which unconditionally apply on all domains). It will be null if the
+ * cache needs to be rebuilt.
+ */
+var unconditionalFilterKeys = null;
+
+/**
  * Object to be used instead when a filter has a blank domains property.
  */
 var defaultDomains = Object.create(null);
@@ -95,16 +94,15 @@ var ElemHide = exports.ElemHide =
     filterByKey = [];
     keyByFilter = Object.create(null);
     filtersByDomain = Object.create(null);
-    filtersBySelector = Object.create(null);
-    unconditionalSelectors = null;
+    filterKeyBySelector = Object.create(null);
+    unconditionalSelectors = unconditionalFilterKeys = null;
     knownExceptions = Object.create(null);
     exceptions = Object.create(null);
     FilterNotifier.emit("elemhideupdate");
   },
 
-  _addToFiltersByDomain: function(filter)
+  _addToFiltersByDomain: function(key, filter)
   {
-    let key = keyByFilter[filter.text];
     let domains = filter.domains || defaultDomains;
     for (let domain in domains)
     {
@@ -135,19 +133,15 @@ var ElemHide = exports.ElemHide =
         exceptions[selector] = [];
       exceptions[selector].push(filter);
 
-      if (usingGetSelectorsForDomain)
+      // 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)
       {
-        // If this is the first exception for a previously unconditionally
-        // applied element hiding selector we need to take care to update the
-        // lookups.
-        let unconditionalFilters = filtersBySelector[selector];
-        if (unconditionalFilters)
-        {
-          for (let f of unconditionalFilters)
-            this._addToFiltersByDomain(f);
-          delete filtersBySelector[selector];
-          unconditionalSelectors = null;
-        }
+        this._addToFiltersByDomain(filterKey, filterByKey[filterKey]);
+        delete filterKeyBySelector[selector];
+        unconditionalSelectors = unconditionalFilterKeys = null;
       }
 
       knownExceptions[filter.text] = true;
@@ -160,27 +154,16 @@ var ElemHide = exports.ElemHide =
       let key = filterByKey.push(filter) - 1;
       keyByFilter[filter.text] = key;
 
-      if (usingGetSelectorsForDomain)
+      if (!(filter.domains || filter.selector in exceptions))
       {
-        if (!(filter.domains || filter.selector in exceptions))
-        {
-          // The new filter's selector is unconditionally applied to all domains
-          let filters = filtersBySelector[filter.selector];
-          if (filters)
-          {
-            filters.push(filter);
-          }
-          else
-          {
-            filtersBySelector[filter.selector] = [filter];
-            unconditionalSelectors = null;
-          }
-        }
-        else
-        {
-          // The new filter's selector only applies to some domains
-          this._addToFiltersByDomain(filter);
-        }
+        // The new filter's selector is unconditionally applied to all domains
+        filterKeyBySelector[filter.selector] = key;
+        unconditionalSelectors = unconditionalFilterKeys = null;
+      }
+      else
+      {
+        // The new filter's selector only applies to some domains
+        this._addToFiltersByDomain(key, filter);
       }
     }
 
@@ -213,31 +196,19 @@ var ElemHide = exports.ElemHide =
       delete filterByKey[key];
       delete keyByFilter[filter.text];
 
-      if (usingGetSelectorsForDomain)
+      if (filter.selector in filterKeyBySelector)
       {
-        let filters = filtersBySelector[filter.selector];
-        if (filters)
-        {
-          if (filters.length > 1)
-          {
-            let index = filters.indexOf(filter);
-            filters.splice(index, 1);
-          }
-          else
-          {
-            delete filtersBySelector[filter.selector];
-            unconditionalSelectors = null;
-          }
-        }
-        else
+        delete filterKeyBySelector[filter.selector];
+        unconditionalSelectors = unconditionalFilterKeys = null;
+      }
+      else
+      {
+        let domains = filter.domains || defaultDomains;
+        for (let domain in domains)
         {
-          let domains = filter.domains || defaultDomains;
-          for (let domain in domains)
-          {
-            let filters = filtersByDomain[domain];
-            if (filters)
-              delete filters[key];
-          }
+          let filters = filtersByDomain[domain];
+          if (filters)
+            delete filters[key];
         }
       }
     }
@@ -265,7 +236,7 @@ var ElemHide = exports.ElemHide =
   /**
    * Retrieves an element hiding filter by the corresponding protocol key
    */
-  getFilterByKey: function(/**String*/ key) /**Filter*/
+  getFilterByKey: function(/**Number*/ key) /**Filter*/
   {
     return (key in filterByKey ? filterByKey[key] : null);
   },
@@ -298,17 +269,50 @@ var ElemHide = exports.ElemHide =
   },
 
   /**
-   * Returns a list of all selectors active on a particular domain, must not be
-   * used in Firefox (when usingGetSelectorsForDomain is false).
+   * Returns a list of selectors that apply on each website unconditionally.
+   * @returns {String[]}
    */
-  getSelectorsForDomain: function(/**String*/ domain, /**Boolean*/ specificOnly)
+  getUnconditionalSelectors: function()
   {
-    if (!usingGetSelectorsForDomain)
-      throw new Error("getSelectorsForDomain can not be used in Firefox!");
-
     if (!unconditionalSelectors)
-      unconditionalSelectors = Object.keys(filtersBySelector);
-    let selectors = specificOnly ? [] : unconditionalSelectors.slice();
+      unconditionalSelectors = Object.keys(filterKeyBySelector);
+    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]);
+    }
+    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)
+  {
+    let filterKeys = [];
+    let selectors = [];
+    if (!specificOnly && !noUnconditional)
+    {
+      selectors = this.getUnconditionalSelectors();
+      if (provideFilterKeys)
+        filterKeys = this.getUnconditionalFilterKeys();
+    }
 
     let seenFilters = Object.create(null);
     let currentDomain = domain ? domain.toUpperCase() : "";
@@ -328,7 +332,11 @@ var ElemHide = exports.ElemHide =
 
           let filter = filters[filterKey];
           if (filter && !this.getException(filter, domain))
+          {
             selectors.push(filter.selector);
+            // It is faster to always push the key, even if not required.
+            filterKeys.push(filterKey);
+          }
         }
       }
 
@@ -339,6 +347,9 @@ var ElemHide = exports.ElemHide =
       currentDomain = nextDot == -1 ? "" : currentDomain.substr(nextDot + 1);
     }
 
-    return selectors;
+    if (provideFilterKeys)
+      return [selectors, filterKeys];
+    else
+      return selectors;
   }
 };