Issue 7450 - Implement hide-if-contains-visible-text snippet

lib/content/snippets.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-present 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 392 matching lines @@
 }
 
 exports["hide-if-shadow-contains"] = makeInjector(hideIfShadowContains,
                                                   toRegExp, regexEscape,
                                                   hideElement);
 
 /**
  * Hides any HTML element or one of its ancestors matching a CSS selector if
  * it matches the provided condition.
  *
- * @param {function} match The function that match the element.
+ * @param {function} match The function that provides the matching condition.
  * @param {string} selector The CSS selector that an HTML element must match
  *   for it to be hidden.
- * @param {string?} [searchSelector] The CSS selector that an HTML element
+ * @param {?string} [searchSelector] The CSS selector that an HTML element
  *   containing the given string must match. Defaults to the value of the
  *   <code>selector</code> argument.
  */
-function hideIfMatch(match, selector = "*", searchSelector = null)
+function hideIfMatches(match, selector, searchSelector)
 {
   if (searchSelector == null)
     searchSelector = selector;
 
-  new MutationObserver(() =>
+  let callback = () =>
   {
     for (let element of document.querySelectorAll(searchSelector))
     {
-      if (match(element))
-      {
-        let closest = element.closest(selector);
-        if (closest)
-          hideElement(closest);
-      }
-    }
-  })
-  .observe(document, {childList: true, characterData: true, subtree: true});
+      let closest = element.closest(selector);
+      if (closest && match(element, closest))
+        hideElement(closest);
+    }
+  };
+  new MutationObserver(callback)
+    .observe(document, {childList: true, characterData: true, subtree: true});
+  callback();
 }
 
 /**
  * Hides any HTML element or one of its ancestors matching a CSS selector if
  * the text content of the element contains a given string.
  *
  * @param {string} search The string to look for in HTML elements. If the
  *   string begins and ends with a slash (<code>/</code>), the text in between
  *   is treated as a regular expression.
  * @param {string} selector The CSS selector that an HTML element must match
  *   for it to be hidden.
- * @param {string?} [searchSelector] The CSS selector that an HTML element
+ * @param {?string} [searchSelector] The CSS selector that an HTML element
  *   containing the given string must match. Defaults to the value of the
  *   <code>selector</code> argument.
  */
 function hideIfContains(search, selector = "*", searchSelector = null)
 {
   let re = toRegExp(search);
 
-  hideIfMatch(element => re.test(element.textContent),
-              selector, searchSelector);
+  hideIfMatches(element => re.test(element.textContent),
+                selector, searchSelector);
 }
 
 exports["hide-if-contains"] = hideIfContains;
 
 /**
  * Hides any HTML element matching a CSS selector if the visible text content
  * of the element contains a given string.
  *
- * @param {string} search The text to match to the visible text. Is considered
+ * @param {string} search The string to match to the visible text. Is considered
  *   visible text that isn't hidden by CSS properties or other means.
  *   If the string begins and ends with a slash (<code>/</code>), the
  *   text in between is treated as a regular expression.
  * @param {string} selector The CSS selector that an HTML element must match
  *   for it to be hidden.
- * @param {string?} [searchSelector] The CSS selector that an HTML element
+ * @param {?string} [searchSelector] The CSS selector that an HTML element
  *   containing the given string must match. Defaults to the value of the
  *   <code>selector</code> argument.
  */
 function hideIfContainsVisibleText(search, selector, searchSelector = null)
 {
   /**
    * Determines if the text inside the element is visible.
-   * @param {Element} element The leaf element we are checking.
-   * @param {?CSSStyleDeclaration} [style] The computed style of element. If
+   * @param {Element} element The element we are checking.
+   * @param {?CSSStyleDeclaration} style The computed style of element. If
    *   falsey it will be queried.
    * @returns {bool} Whether the text is visible.
    */
   function isTextVisible(element, style)
   {
     if (!style)
       style = window.getComputedStyle(element);
 
     if (style.getPropertyValue("opacity") == "0")
       return false;
     if (style.getPropertyValue("font-size") == "0px")
       return false;
-    if (style.getPropertyValue("color") ==
-        style.getPropertyValue("background-color"))
+
+    let color = style.getPropertyValue("color");
+    // if color is transparent...
+    if (color == "rgba(0, 0, 0, 0)")
       return false;
+    if (style.getPropertyValue("background-color") == color)
+      return false;
 
     return true;
   }
 
   /**
-   * Returns the visible text content from an element and its children.
+   * Check if an element is visible
+   * @param {Element} element The element to check visibility of.
+   * @param {?CSSStyleDeclaration} style The computed style of element. If
+   *   falsey it will be queried.
+   * @param {?Element} closest The closest parent to reach.
+   * @return {bool} Whether the element is visible.
+   */
+  function isVisible(element, style, closest)
+  {
+    if (!style)
+      style = window.getComputedStyle(element);
+
+    if (style.getPropertyValue("display") == "none")
+      return false;
+    let visibility = style.getPropertyValue("visibility");
+    if (visibility == "hidden" || visibility == "collapse")
+      return false;
+
+    if (!closest || element == closest)
+      return true;
+
+    let parent = element.parentElement;
+    if (!parent)
+      return true;
+
+    return isVisible(parent, null, closest);
+  }
+
+  /**
+   * Returns the visible text content from an element and its descendants.
    * @param {Element} element The element whose visible text we want.
+   * @param {Element} closest The closest parent to reach while checking
+   *   for visibility.
    * @returns {string} The text that is visible.
    */
-  function getVisibleContent(element)
+  function getVisibleContent(element, closest)
   {
     let style = window.getComputedStyle(element);
-    if (style.getPropertyValue("display") == "none")
-      return "";
-    let visibility = style.getPropertyValue("visibility");
-    if (visibility == "hidden" || visibility == "collapse")
+    if (!isVisible(element, style, closest))
       return "";
 
     let text = "";
     for (let node of element.childNodes)
     {
       switch (node.nodeType)
       {
         case Node.ELEMENT_NODE:
-          text += getVisibleContent(node);
+          text += getVisibleContent(node, element);
           break;
         case Node.TEXT_NODE:
           if (isTextVisible(element, style))
             text += node.nodeValue;
           break;
       }
     }
     return text;
   }
 
   let re = toRegExp(search);
 
-  hideIfMatch(element =>
-  {
-    let content = getVisibleContent(element);
-    return re.test(content);
-  }, selector, searchSelector);
-}
-
-exports["hide-if-contains-visible-text"] =
-  makeInjector(hideIfContainsVisibleText, hideIfMatch, hideElement);
+  hideIfMatches(
+    (element, closest) => re.test(getVisibleContent(element, closest)),
+    selector, searchSelector);
+}
+
+exports["hide-if-contains-visible-text"] = hideIfContainsVisibleText;
 
 /**
  * Hides any HTML element or one of its ancestors matching a CSS selector if
  * the text content of the element contains a given string and, optionally, if
  * the element's computed style contains a given string.
  *
  * @param {string} search The string to look for in HTML elements. If the
  *   string begins and ends with a slash (<code>/</code>), the text in between
  *   is treated as a regular expression.
  * @param {string} selector The CSS selector that an HTML element must match
@@ skipping 438 matching lines @@
 
       args[0] = url.href;
     }
 
     return fetch_.apply(this, args);
   };
 }
 
 exports["strip-fetch-query-parameter"] = makeInjector(stripFetchQueryParameter,
                                                       toRegExp, regexEscape);