Issue 5422 - Properly build props selector

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 MIN_INVOCATION_INTERVAL = 3000;
 const abpSelectorRegexp = /:-abp-([\w-]+)\(/i;
 
 function splitSelector(selector)
 {
   if (selector.indexOf(",") == -1)
     return [selector];
 
   let selectors = [];
   let start = 0;
   let level = 0;
@@ skipping 10 matching lines @@
     else if (sep == "")
     {
       if (chr == '"' || chr == "'")
         sep = chr;
       else if (chr == "(")  // don't split between parentheses
         level++;            // e.g. :matches(div,span)
       else if (chr == ")")
         level = Math.max(0, level - 1);
       else if (chr == "," && level == 0)
       {
-        selectors.push(selector.substring(start, i).trim());
+        selectors.push(selector.substring(start, i));
         start = i + 1;
       }
     }
   }
 
-  selectors.push(selector.substring(start).trim());
+  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} One-based index like for :nth-child(), or 0 on error.
  */
 function positionInParent(node)
 {
   let {children} = node.parentNode;
@@ skipping 121 matching lines @@
 const incompletePrefixRegexp = /[\s>+~]$/;
 
 function HasSelector(selectors)
 {
   this._innerSelectors = selectors;
 }
 
 HasSelector.prototype = {
   requiresHiding: true,
 
+  get dependsOnStyles()
+  {
+    return this._innerSelectors.some(selector => selector.dependsOnStyles);
+  },
+
   *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 {StringifiedStyle[]} styles the stringified style objects.
    */
   *getElements(prefix, subtree, styles)
   {
     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, newPrefix + " ",
-                          element, styles);
+      let iter = evaluate(this._innerSelectors, 0, "", 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(selector))
+        if (element.querySelector(selector))
           yield element;
     }
   }
 };
 
 function ContainsSelector(textContent)
 {
   this._text = textContent;
 }
 
@@ skipping 27 matching lines @@
       .replace("\\x7B ", "{").replace("\\x7D ", "}");
   }
   else
     regexpString = filterToRegExp(propertyExpression);
 
   this._regexp = new RegExp(regexpString, "i");
 }
 
 PropsSelector.prototype = {
   preferHideWithSelector: true,
+  dependsOnStyles: true,
 
   *findPropsSelectors(styles, prefix, regexp)
   {
-    let actualPrefix = (prefix && !incompletePrefixRegexp.test(prefix)) ?
-        prefix + " " : prefix;

[Wladimir Palant, 2017/08/16 08:37:02]

No, this is not what we want. Consider
.abp-testsuite-fail:-abp-properties(border: 4px solid #B30B0B) for example. This
should resolve into .abp-testsuite-fail.abp-testsuite-fail and hide the element.
Your changes will insert a space into this selector which will no longer match
anything. If a space is needed, it should be part of the filter.

[hub, 2017/08/16 19:50:32]

Acknowledged.

     for (let style of styles)
       if (regexp.test(style.style))
         for (let subSelector of style.subSelectors)
         {
-          if (subSelector == "*")
-            subSelector = "";

[Wladimir Palant, 2017/08/16 08:37:02]

What if we have a filter like `:-abp-properties(foo)` and the only matching
subselector is "*"? This will produce an empty selector. Also, please consider a
filter like `foo+:-abp-properties(foo)`, we'll produce an invalid selector here.
Besides, this doesn't address the case where subSelector is something like
"*.foo"

It seems that we need to check whether subSelector starts with an asterisk. If
that's the case and we have a prefix that isn't incomplete, we should strip the
asterisk from subSelector. All the other changes here seem unnecessary.

[hub, 2017/08/16 19:50:32]

Done.

-          yield actualPrefix + subSelector;
+          if (subSelector.startsWith("*") &&
+              !incompletePrefixRegexp.test(prefix))
+          {
+            subSelector = subSelector.substr(1);
+          }
+          let idx = subSelector.lastIndexOf("::");
+          if (idx != -1)
+            subSelector = subSelector.substr(0, idx);
+          yield prefix + subSelector;
         }
   },
 
   *getSelectors(prefix, subtree, styles)
   {
     for (let selector of this.findPropsSelectors(styles, prefix, this._regexp))
       yield [selector, subtree];
   }
 };
 
@@ skipping 79 matching lines @@
     {
       this.window.console.error(
         new SyntaxError("Failed to parse Adblock Plus " +
                         `selector ${selector}, can't ` +
                         "have a lonely :-abp-contains()."));
       return null;
     }
     return selectors;
   },
 
+  _lastInvocation: 0,
+
+  /**
+   * Processes the current document and applies all rules to it.
+   * @param {CSSStyleSheet[]} [stylesheets]
+   *    The list of new stylesheets that have been added to the document and
+   *    made reprocessing necessary. This parameter shouldn't be passed in for
+   *    the initial processing, all of document's stylesheets will be considered
+   *    then and all rules, including the ones not dependent on styles.
+   */
   addSelectors(stylesheets)
   {
+    this._lastInvocation = Date.now();
+
     let selectors = [];
     let selectorFilters = [];
 
     let elements = [];
     let elementFilters = [];
 
     let cssStyles = [];
+
+    let stylesheetOnlyChange = !!stylesheets;
+    if (!stylesheets)
+      stylesheets = this.window.document.styleSheets;
 
     // Chrome < 51 doesn't have an iterable StyleSheetList
     // https://issues.adblockplus.org/ticket/5381
     for (let i = 0; i < stylesheets.length; i++)
     {
       let stylesheet = stylesheets[i];
       // 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;
 
         cssStyles.push(stringifyStyle(rule));
       }
     }
 
     let {document} = this.window;
     for (let pattern of this.patterns)
     {
+      if (stylesheetOnlyChange &&
+          !pattern.selectors.some(selector => selector.dependsOnStyles))
+      {
+        continue;
+      }
+
       for (let selector of evaluate(pattern.selectors,
                                     0, "", document, cssStyles))
       {
         if (pattern.selectors.some(s => s.preferHideWithSelector) &&
             !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, selectorFilters);
     this.hideElemsFunc(elements, elementFilters);
   },
 
+  _stylesheetQueue: null,
+
   onLoad(event)
   {
     let stylesheet = event.target.sheet;
     if (stylesheet)
-      this.addSelectors([stylesheet]);
+    {
+      if (!this._stylesheetQueue &&
+          Date.now() - this._lastInvocation < MIN_INVOCATION_INTERVAL)
+      {
+        this._stylesheetQueue = [];
+        this.window.setTimeout(() =>
+        {
+          let stylesheets = this._stylesheetQueue;
+          this._stylesheetQueue = null;
+          this.addSelectors(stylesheets);
+        }, MIN_INVOCATION_INTERVAL - (Date.now() - this._lastInvocation));
+      }
+
+      if (this._stylesheetQueue)
+        this._stylesheetQueue.push(stylesheet);
+      else
+        this.addSelectors([stylesheet]);
+    }
   },
 
   apply()
   {
     this.getFiltersFunc(patterns =>
     {
       this.patterns = [];
       for (let pattern of patterns)
       {
         let selectors = this.parseSelector(pattern.selector);
         if (selectors != null && selectors.length > 0)
           this.patterns.push({selectors, text: pattern.text});
       }
 
       if (this.patterns.length > 0)
       {
         let {document} = this.window;
-        this.addSelectors(document.styleSheets);
+        this.addSelectors();
         document.addEventListener("load", this.onLoad.bind(this), true);
       }
     });
   }
 };