Issue 3143 - Filter elements with :-abp-has()

chrome/content/elemHideEmulation.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2017 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
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 /* globals filterToRegExp */
 
 "use strict";
 
+const abpSelectorRegexp = /:-abp-([\w-]+)\(/i;
+
+let reportError = () => {};
+
 function splitSelector(selector)
 {
   if (selector.indexOf(",") == -1)
     return [selector];
 
   let selectors = [];
   let start = 0;
   let level = 0;
   let sep = "";
 
@@ skipping 19 matching lines @@
         start = i + 1;
       }
     }
   }
 
   selectors.push(selector.substring(start));
   return selectors;
 }
 
 /** Return position of node from parent.
- * @param {Node} node - the node to find the position of.
- * @return {number} 1 base index like for :nth-child(), or 0 on error.
+ * @param {Node} node the node to find the position of.
+ * @return {number} One-based index like for :nth-child(), or 0 on error.
  */
 function positionInParent(node)
 {
-  if (!node)
-    return 0;
   let {children} = node.parentNode;
   for (let i = 0; i < children.length; i++)
     if (children[i] == node)
       return i + 1;
   return 0;
 }
 
 function makeSelector(node, selector)
 {
   if (!node.parentElement)
   {
     let newSelector = ":root";
     if (selector)
-      newSelector += " > ";
-    return newSelector + selector;
+      newSelector += " > " + selector;
+    return newSelector;
   }
   let idx = positionInParent(node);
   if (idx > 0)
   {
     let newSelector = `${node.tagName}:nth-child(${idx})`;
     if (selector)
-      newSelector += " > ";
-    return makeSelector(node.parentElement, newSelector + selector);
+      newSelector += " > " + selector;
+    return makeSelector(node.parentElement, newSelector);
   }
 
   return selector;
 }
 
-const abpSelectorRegexp = /:-abp-(properties|has|[A-Za-z\d-]*)\(/i;
-
-function parseSelectorContent(content, quoted = false)
+function parseSelectorContent(content, startIndex)
 {
   let parens = 1;
-  let i = 0;
   let quote = null;
-  let originalLength = content.length;
-  if (quoted)
-    content = content.trim();
-  while (i < content.length)
+  let i = startIndex;
+  for (; i < content.length; i++)
   {
     let c = content[i];
-    if (quoted && i == 0)
-    {
-      if (c != "'" && c != '"')
-        return null;
-    }
     if (c == "\\")
+    {
+      // Ignore escaped characters
       i++;
+    }
     else if (quote)
     {
       if (c == quote)
         quote = null;
     }
     else if (c == "'" || c == '"')
-    {
       quote = c;
-    }
     else if (c == "(")
       parens++;
     else if (c == ")")
     {
       parens--;
       if (parens == 0)
         break;
     }
-    i++;
-  }
+  }
+
   if (parens > 0)
     return null;
-  if (quoted)
-  {
-    let end = content.substr(0, i).lastIndexOf(content[0]);
-    return {text: content.substr(1, end - 1),
-      end: i + (originalLength - content.length)};
-  }
-  return {text: content.substr(0, i), end: i};
-}
-
-function parseSelector(selector, level = 0)
+  return {text: content.substring(startIndex, i), end: i};
+}
+
+/** Parse the selector
+ * @param {string} selector the selector to parse
+ * @return {Object} selectors is an array of objects,
+ * or null in case of errors. hide is true if we'll hide
+ * elements instead of styles..
+ */
+function parseSelector(selector)
 {
   if (selector.length == 0)
     return [];
 
   let match = abpSelectorRegexp.exec(selector);
   if (!match)
     return [new PlainSelector(selector)];
 
   let selectors = [];
-  let suffixStart = match.index;
-  if (suffixStart > 0)
-    selectors.push(new PlainSelector(selector.substr(0, suffixStart)));
+  if (match.index > 0)
+    selectors.push(new PlainSelector(selector.substr(0, match.index)));
 
   let startIndex = match.index + match[0].length;
-  let content = null;
+  let content = parseSelectorContent(selector, startIndex);
+  if (!content)
+  {
+    reportError(new SyntaxError("Failed to parse Adblock Plus " +
+                                `selector ${selector}, ` +
+                                "due to unmatched parentheses."));
+    return null;
+  }
   if (match[1] == "properties")
-  {
-    content = parseSelectorContent(selector.substr(startIndex), true);
-    if (content == null)
-    {
-      console.error(new SyntaxError("Failed to parse AdBlock Plus " +
-                                    `selector ${selector}, invalid ` +
-                                    "properties string."));
-      return null;
-    }
-
     selectors.push(new PropsSelector(content.text));
-  }
   else if (match[1] == "has")
   {
-    if (level > 0)
-    {
-      console.error(new SyntaxError("Failed to parse AdBlock Plus " +
-                                    `selector ${selector}, invalid ` +
-                                    "nested :-abp-has()."));
-      return null;
-    }
-
-    content = parseSelectorContent(selector.substr(startIndex));
-    if (content == null)
-    {
-      console.error(new SyntaxError("Failed parsing AdBlock Plus " +
-                                    `selector ${selector}, didn't ` +
-                                    "find closing parenthesis."));
-      return null;
-    }
-
     let hasSelector = new HasSelector(content.text);
     if (!hasSelector.valid())
       return null;
     selectors.push(hasSelector);
   }
   else
   {
     // this is an error, can't parse selector.
-    console.error(new SyntaxError("Failed parsing AdBlock Plus " +
-                                  `selector ${selector}, invalid ` +
-                                  `pseudo-class -abp-${match[1]}.`));
+    reportError(new SyntaxError("Failed to parse Adblock Plus " +
+                                `selector ${selector}, invalid ` +
+                                `pseudo-class :-abp-${match[1]}().`));
     return null;
   }
 
-  suffixStart = startIndex + content.end + 1;
-
-  let suffix = parseSelector(selector.substr(suffixStart), level);
+  let suffix = parseSelector(selector.substr(content.end + 1));
   if (suffix == null)
     return null;
 
   selectors.push(...suffix);
 
   return selectors;
 }
 
-function *findPropsSelectors(styles, prefix, regexp)
-{
-  for (let style of styles)
-    if (regexp.test(style.style))
-      for (let subSelector of style.subSelectors)
-        yield prefix + subSelector;
-}
-
-function stringifyStyle(style)
+/** Stringified style objects
+ * @typedef {Object} StringifiedStyle
+ * @property {string} style CSS style represented by a string.
+ * @property {string[]} subSelectors selectors the CSS properties apply to.
+ */
+
+/**
+ * Produce a string representation of the stylesheet entry.
+ * @param {CSSStyleRule} rule the CSS style rule.
+ * @return {StringifiedStyle} the stringified style.
+ */
+function stringifyStyle(rule)
 {
   let styles = [];
-  for (let i = 0; i < style.length; i++)
-  {
-    let property = style.item(i);
-    let value = style.getPropertyValue(property);
-    let priority = style.getPropertyPriority(property);
-    styles.push(property + ": " + value + (priority ? " !" + priority : "") +
-                ";");
+  for (let i = 0; i < rule.style.length; i++)
+  {
+    let property = rule.style.item(i);
+    let value = rule.style.getPropertyValue(property);
+    let priority = rule.style.getPropertyPriority(property);
+    styles.push(`${property}: ${value}${priority ? " !" + priority : ""};`);
   }
   styles.sort();
-  return styles.join(" ");
+  return {
+    style: styles.join(" "),
+    subSelectors: splitSelector(rule.selectorText)
+  };
 }
 
 function* evaluate(chain, index, prefix, subtree, styles)
 {
   if (index >= chain.length)
   {
     yield prefix;
     return;
   }
   for (let [selector, element] of
        chain[index].getSelectors(prefix, subtree, styles))
     yield* evaluate(chain, index + 1, selector, element, styles);
 }
 
 function PlainSelector(selector)
 {
   this._selector = selector;
 }
 
 PlainSelector.prototype = {
   /**
    * Generator function returning a pair of selector
    * string and subtree.
-   * @param {String} prefix - the prefix for the selector.
-   * @param {Node} subtree - the subtree we work on.
-   * @param {Array} styles - the stringified stylesheets.
+   * @param {string} prefix the prefix for the selector.
+   * @param {Node} subtree the subtree we work on.
+   * @param {StringifiedStyle[]} styles the stringified style objects.
    */
   *getSelectors(prefix, subtree, styles)
   {
     yield [prefix + this._selector, subtree];
+  }
+};
+
+const incompletePrefixRegexp = /[\s>+~]$/;
+
+function HasSelector(selector)
+{
+  this._innerSelectors = parseSelector(selector);
+}
+
+HasSelector.prototype = {
+  requiresHiding: true,
+
+  valid()
+  {
+    return this._innerSelectors != null;
+  },
+
+  *getSelectors(prefix, subtree, styles)
+  {
+    for (let element of this.getElements(prefix, subtree, styles))
+      yield [makeSelector(element, ""), element];
   },
 
   /**
    * Generator function returning selected elements.
-   * @param {String} prefix - the prefix for the selector.
-   * @param {Node} subtree - the subtree we work on.
-   * @param {Array} styles - the stringified stylesheets.
+   * @param {string} prefix the prefix for the selector.
+   * @param {Node} subtree the subtree we work on.
+   * @param {StringifiedStyle[]} styles the stringified style objects.
    */
   *getElements(prefix, subtree, styles)
   {
-    for (let [selector] of this.getSelectors(prefix, subtree, styles))
-      for (let element of subtree.querySelectorAll(selector))
-        yield element;
-  }
-};
-
-const prefixEndRegexp = /[\s>+~]$/;
-
-function HasSelector(selector, level = 0)
-{
-  this._innerSelectors = parseSelector(selector, level + 1);
-}
-
-HasSelector.prototype = {
-  valid()
-  {
-    return this._innerSelectors != null;
-  },
-
-  *getSelectors(prefix, subtree, styles)
-  {
-    for (let element of this.getElements(prefix, subtree, styles))
-      yield [makeSelector(element, ""), element];
-  },
-
-  *getElements(prefix, subtree, styles)
-  {
-    let actualPrefix = (!prefix || prefixEndRegexp.test(prefix)) ?
+    let actualPrefix = (!prefix || incompletePrefixRegexp.test(prefix)) ?
         prefix + "*" : prefix;
     let elements = subtree.querySelectorAll(actualPrefix);
     for (let element of elements)
     {
       let newPrefix = makeSelector(element, "");
-      let iter = evaluate(this._innerSelectors, 0, "", element, styles);
+      let iter = evaluate(this._innerSelectors, 0, newPrefix + " ",
+                          element, styles);
       for (let selector of iter)
         // we insert a space between the two. It becomes a no-op if selector
         // doesn't have a combinator
-        if (subtree.querySelector(newPrefix + " " + selector))
+        if (subtree.querySelector(selector))
           yield element;
     }
   }
 };
 
 function PropsSelector(propertyExpression)
 {
   let regexpString;
   if (propertyExpression.length >= 2 && propertyExpression[0] == "/" &&
       propertyExpression[propertyExpression.length - 1] == "/")
   {
     regexpString = propertyExpression.slice(1, -1)
       .replace("\\x7B ", "{").replace("\\x7D ", "}");
   }
   else
     regexpString = filterToRegExp(propertyExpression);
 
   this._regexp = new RegExp(regexpString, "i");
 }
 
 PropsSelector.prototype = {
+  *findPropsSelectors(styles, prefix, regexp)
+  {
+    for (let style of styles)
+      if (regexp.test(style.style))
+        for (let subSelector of style.subSelectors)
+          yield prefix + subSelector;
+  },
+
   *getSelectors(prefix, subtree, styles)
   {
-    for (let selector of findPropsSelectors(styles, prefix, this._regexp))
+    for (let selector of this.findPropsSelectors(styles, prefix, this._regexp))
       yield [selector, subtree];
-  },
-
-  *getElements(prefix, subtree, styles)
-  {
-    for (let [selector] of this.getSelectors(prefix, subtree, styles))
-      for (let subElement of subtree.querySelectorAll(selector))
-        yield subElement;
   }
 };
 
-function ElemHideEmulation(window, getFiltersFunc, addSelectorsFunc)
+function ElemHideEmulation(window, getFiltersFunc, addSelectorsFunc,
+                           hideElemsFunc)
 {
   this.window = window;
   this.getFiltersFunc = getFiltersFunc;
   this.addSelectorsFunc = addSelectorsFunc;
+  this.hideElemsFunc = hideElemsFunc;
 }
 
 ElemHideEmulation.prototype = {
   isSameOrigin(stylesheet)
   {
     try
     {
       return new URL(stylesheet.href).origin == this.window.location.origin;
     }
     catch (e)
     {
       // Invalid URL, assume that it is first-party.
       return true;
     }
   },
 
   addSelectors(stylesheets)
   {
     let selectors = [];
-    let filters = [];
+    let selectorFilters = [];
+
+    let elements = [];
+    let elementFilters = [];
 
     let cssStyles = [];
 
     for (let stylesheet of stylesheets)
     {
       // Explicitly ignore third-party stylesheets to ensure consistent behavior
       // between Firefox and Chrome.
       if (!this.isSameOrigin(stylesheet))
         continue;
 
       let rules = stylesheet.cssRules;
       if (!rules)
         continue;
 
       for (let rule of rules)
       {
         if (rule.type != rule.STYLE_RULE)
           continue;
 
-        let style = stringifyStyle(rule.style);
-        let subSelectors = splitSelector(rule.selectorText);
-        cssStyles.push({style, subSelectors});
+        cssStyles.push(stringifyStyle(rule));
       }
     }
 
-    for (let patterns of this.selPatterns)
-      for (let selector of evaluate(patterns.selectors,
+    let {document} = this.window;
+    for (let pattern of this.patterns)
+    {
+      for (let selector of evaluate(pattern.selectors,
                                     0, "", document, cssStyles))
       {
-        selectors.push(selector);
-        filters.push(patterns.text);
+        if (!pattern.selectors.some(s => s.requiresHiding))
+        {
+          selectors.push(selector);
+          selectorFilters.push(pattern.text);
+        }
+        else
+        {
+          for (let element of document.querySelectorAll(selector))
+          {
+            elements.push(element);
+            elementFilters.push(pattern.text);
+          }
+        }
       }
-
-    this.addSelectorsFunc(selectors, filters);
+    }
+
+    this.addSelectorsFunc(selectors, selectorFilters);
+    this.hideElemsFunc(elements, elementFilters);
   },
 
   onLoad(event)
   {
     let stylesheet = event.target.sheet;
     if (stylesheet)
       this.addSelectors([stylesheet]);
   },
 
   apply()
   {
     this.getFiltersFunc(patterns =>
     {
-      this.selPatterns = [];
-
+      let oldReportError = reportError;
+      reportError = error => this.window.console.error(error);
+
+      this.patterns = [];
       for (let pattern of patterns)
       {
         let selectors = parseSelector(pattern.selector);
         if (selectors != null && selectors.length > 0)
-          this.selPatterns.push({selectors, text: pattern.text});
+          this.patterns.push({selectors, text: pattern.text});
       }
 
-      if (this.selPatterns.length > 0)
+      if (this.patterns.length > 0)
       {
         let {document} = this.window;
         this.addSelectors(document.styleSheets);
         document.addEventListener("load", this.onLoad.bind(this), true);
       }
+      reportError = oldReportError;
     });
   }
 };