Issue 2390 - Created filter class for CSS property filters

lib/filterClasses.js

Index: lib/filterClasses.js
===================================================================
--- a/lib/filterClasses.js
+++ b/lib/filterClasses.js
@@ -20,6 +20,7 @@
  */
 
 let {FilterNotifier} = require("filterNotifier");
+let {Utils} = require("utils");
 
 /**
  * Abstract base class for filters
@@ -85,6 +86,12 @@
  * @type RegExp
  */
 Filter.optionsRegExp = /\$(~?[\w\-]+(?:=[^,\s]+)?(?:,~?[\w\-]+(?:=[^,\s]+)?)*)$/;
+/**
+ * Regular expression that CSS property filters should match
+ * Properties must not contain " or '
+ * @type RegExp
+ */
+Filter.csspropertyRegExp = /\[\-abp\-properties=(["'])([^"']+)\1\]/;
 
 /**
  * Creates a filter of correct type from its text representation - does the basic parsing and
@@ -160,6 +167,27 @@
 };
 
 /**
+ * Converts filter text into regular expression string
+ * @param {String} text as in Filter()
+ * @return {String} regular expression representation of filter text
+ */
+Filter.toRegExp = function(text)
+{
+  return text
+    .replace(/\*+/g, "*")        // remove multiple wildcards
+    .replace(/\^\|$/, "^")       // remove anchors following separator placeholder
+    .replace(/\W/g, "\\$&")      // escape special symbols
+    .replace(/\\\*/g, ".*")      // replace wildcards by .*
+    // process separator placeholders (all ANSI characters but alphanumeric characters and _%.-)
+    .replace(/\\\^/g, "(?:[\\x00-\\x24\\x26-\\x2C\\x2F\\x3A-\\x40\\x5B-\\x5E\\x60\\x7B-\\x7F]|$)")
+    .replace(/^\\\|\\\|/, "^[\\w\\-]+:\\/+(?!\\/)(?:[^\\/]+\\.)?") // process extended anchor at expression start
+    .replace(/^\\\|/, "^")       // process anchor at expression start
+    .replace(/\\\|$/, "$")       // process anchor at expression end
+    .replace(/^(\.\*)/, "")      // remove leading wildcards
+    .replace(/(\.\*)$/, "");     // remove trailing wildcards
+}
+
+/**
  * Class for invalid filters
  * @param {String} text see Filter()
  * @param {String} reason Reason why this filter is invalid
@@ -543,20 +571,7 @@
     if (prop)
       return prop.value;
 
-    // Remove multiple wildcards
-    let source = this.regexpSource
-      .replace(/\*+/g, "*")        // remove multiple wildcards
-      .replace(/\^\|$/, "^")       // remove anchors following separator placeholder
-      .replace(/\W/g, "\\$&")      // escape special symbols
-      .replace(/\\\*/g, ".*")      // replace wildcards by .*
-      // process separator placeholders (all ANSI characters but alphanumeric characters and _%.-)
-      .replace(/\\\^/g, "(?:[\\x00-\\x24\\x26-\\x2C\\x2F\\x3A-\\x40\\x5B-\\x5E\\x60\\x7B-\\x7F]|$)")
-      .replace(/^\\\|\\\|/, "^[\\w\\-]+:\\/+(?!\\/)(?:[^\\/]+\\.)?") // process extended anchor at expression start
-      .replace(/^\\\|/, "^")       // process anchor at expression start
-      .replace(/\\\|$/, "$")       // process anchor at expression end
-      .replace(/^(\.\*)/, "")      // remove leading wildcards
-      .replace(/(\.\*)$/, "");     // remove trailing wildcards
-
+    let source = Filter.toRegExp(this.regexpSource);
     let regexp = new RegExp(source, this.matchCase ? "" : "i");
     Object.defineProperty(this, "regexp", {value: regexp});
     return regexp;
@@ -861,7 +876,7 @@
  * @param {String} tagName    tag name part (can be empty)
  * @param {String} attrRules  attribute matching rules (can be empty)
  * @param {String} selector   raw CSS selector (can be empty)
- * @return {ElemHideFilter|ElemHideException|InvalidFilter}
+ * @return {ElemHideFilter|ElemHideException|CSSPropertyFilter|InvalidFilter}
  */
 ElemHideBase.fromText = function(text, domain, isException, tagName, attrRules, selector)
 {
@@ -872,23 +887,24 @@
 
     let id = null;
     let additional = "";
-    if (attrRules) {
+    if (attrRules)
+    {
       attrRules = attrRules.match(/\([\w\-]+(?:[$^*]?=[^\(\)"]*)?\)/g);
-      for (let rule of attrRules) {
+      for (let rule of attrRules)
+      {
         rule = rule.substr(1, rule.length - 2);
         let separatorPos = rule.indexOf("=");
-        if (separatorPos > 0) {
+        if (separatorPos > 0)
+        {
           rule = rule.replace(/=/, '="') + '"';
           additional += "[" + rule + "]";
         }
-        else {
+        else
+        {
           if (id)
-          {
-            let {Utils} = require("utils");
             return new InvalidFilter(text, Utils.getString("filter_elemhide_duplicate_id"));
-          }
-          else
-            id = rule;
+
+          id = rule;
         }
       }
     }
@@ -898,15 +914,23 @@
     else if (tagName || additional)
       selector = tagName + additional;
     else
-    {
-      let {Utils} = require("utils");
       return new InvalidFilter(text, Utils.getString("filter_elemhide_nocriteria"));
-    }
   }
+
   if (isException)
     return new ElemHideException(text, domain, selector);
-  else
-    return new ElemHideFilter(text, domain, selector);
+
+  if (Filter.csspropertyRegExp.test(selector))

[Wladimir Palant, 2015/06/05 22:08:59]

How about actually storing the result of this selector match?

let match = Filter.csspropertyRegExp.exec(selector);
if (match)
 ...

You can then pass in the match[2], selector.substr(0, match.index) and
selector.substr(match.index + match[0].length) as parameters to the
CSSPropertyFilter constructor - no need to match again and no need to call
String.split().

[Thomas Greiner, 2015/06/08 14:33:43]

Done. I don't really mind either approach.

Note that my approach focused on avoiding parameter redundancy in the
constructor signature since performance should hopefully not be an issue here.

+  {
+    // CSS property filters are inefficient so we need to make sure that
+    // they're only applied if they specify active domains
+    if (!/,[^~][^,.]*\.[^,]/.test("," + domain))
+      return new InvalidFilter(text, Utils.getString("filter_cssproperty_nodomain"));
+
+    return new CSSPropertyFilter(text, domain, selector);
+  }
+
+  return new ElemHideFilter(text, domain, selector);
 };
 
 /**
@@ -946,3 +970,63 @@
 {
   __proto__: ElemHideBase.prototype
 };
+
+/**
+ * Class for CSS property filters
+ * @param {String} text       see Filter()
+ * @param {String} domains    see ElemHideBase()
+ * @param {String} selector   see ElemHideBase()
+ * @constructor
+ * @augments ElemHideBase
+ */
+function CSSPropertyFilter(text, domains, selector)
+{
+  ElemHideBase.call(this, text, domains, selector);
+
+  let properties;
+  [properties, , this.regexpSource] = selector.match(Filter.csspropertyRegExp);
+  [this.selectorPrefix, this.selectorSuffix] = selector.split(properties);
+}
+exports.CSSPropertyFilter = CSSPropertyFilter;
+
+CSSPropertyFilter.prototype =
+{
+  __proto__: ElemHideBase.prototype,
+
+  /**
+   * Expression from which a regular expression should be generated for matching
+   * CSS properties - for delayed creation of the regexpString property
+   * @type String
+   */
+  regexpSource: null,
+  /**
+   * Substring of CSS selector before properties for the HTML elements that
+   * should be hidden
+   * @type String
+   */
+  selectorPrefix: null,
+  /**
+   * Substring of CSS selector after properties for the HTML elements that
+   * should be hidden
+   * @type String
+   */
+  selectorSuffix: null,
+
+  /**
+   * Raw regular expression string to be used when testing CSS properties
+   * against this filter
+   * @type String
+   */
+  get regexpString()
+  {
+    // Despite this property being cached, the getter is called
+    // several times on Safari, due to WebKit bug 132872
+    let prop = Object.getOwnPropertyDescriptor(this, "regexpString");
+    if (prop)
+      return prop.value;
+
+    let regexp = Filter.toRegExp(this.regexpSource);
+    Object.defineProperty(this, "regexpString", {value: regexp});
+    return regexp;
+  }
+};