Performance (#265)

* precursor performance changes

* Allow caller to bypass entire DOM walk

* Allow for other 'requires' beyond 'consoleAPI'

* Collect 'hidden' and 'disabled' info during DOM traversal

* Start using new 'hidden' and 'disabled' flags

* Optionally collect 'idreferrers' while traversing DOM

* Start using new 'idreferrers' flag

Author: ricksbrown

Changelog.md

@@ -1,3 +1,7 @@
+### Enhancements
+
+* Performance enhancements (#263)
+
 ## 2.10.1-rc.0 - 2016-01-13
 
 ### Bug fixes:

src/audits/ControlsWithoutLabel.js

@@ -47,8 +47,8 @@ axs.AuditRules.addRule({
         }
         return true;
     },
-    test: function(control) {
-        if (axs.utils.isElementOrAncestorHidden(control))
+    test: function(control, flags) {
+        if (flags.hidden)
             return false;
         if (control.tagName.toLowerCase() == 'input' &&
             control.type == 'button' &&

src/audits/DuplicateId.js

@@ -25,15 +25,35 @@ axs.AuditRules.addRule({
     heading: 'Any ID referred to via an IDREF must be unique in the DOM',
     url: 'https://github.com/GoogleChrome/accessibility-developer-tools/wiki/Audit-Rules#ax_html_02',
     severity: axs.constants.Severity.SEVERE,
-    relevantElementMatcher: function(element) {
-        if (element.hasAttribute('id')) {
-            var referrers = axs.utils.getIdReferrers(element);
-            return referrers.some(function(referrer) {
-                return !axs.utils.isElementOrAncestorHidden(referrer);
+    opt_requires: {
+        idRefs: true
+    },
+    /**
+     * @this {axs.AuditRule}
+     */
+    relevantElementMatcher: function(element, flags) {
+        if (flags.idrefs.length && !flags.hidden) {
+            this.relatedElements.push({
+                element: element,
+                flags: flags
             });
         }
+        if (element.hasAttribute('id')) {
+            return true;
+        }
         return false;
     },
+    /**
+     * @this {axs.AuditRule}
+     */
+    isRelevant: function(element, flags) {
+        var id = element.id;
+        var level = flags.level;
+        return this.relatedElements.some(function(related) {
+            var idrefs = related.flags.idrefs;
+            return related.flags.level === level && idrefs.indexOf(id) >= 0;
+        });
+    },
     test: function(element) {
         /*
          * Checks for duplicate IDs within the context of this element.

src/audits/FocusableElementNotVisibleAndNotAriaHidden.js

@@ -50,8 +50,8 @@ axs.AuditRules.addRule({
         return true;
 
     },
-    test: function(element) {
-        if (axs.utils.isElementOrAncestorHidden(element))
+    test: function(element, flags) {
+        if (flags.hidden)
             return false;
         element.focus();
         return !axs.utils.elementIsVisible(element);

src/audits/ImageWithoutAltText.js

@@ -23,9 +23,8 @@ axs.AuditRules.addRule({
     heading: 'Images should have a text alternative or presentational role',
     url: 'https://github.com/GoogleChrome/accessibility-developer-tools/wiki/Audit-Rules#ax_text_02',
     severity: axs.constants.Severity.WARNING,
-    relevantElementMatcher: function(element) {
-        return axs.browserUtils.matchSelector(element, 'img') &&
-            !axs.utils.isElementOrAncestorHidden(element);
+    relevantElementMatcher: function(element, flags) {
+        return axs.browserUtils.matchSelector(element, 'img') && !flags.hidden;
     },
     test: function(image) {
         var imageIsPresentational = (image.hasAttribute('alt') && image.alt == '') || image.getAttribute('role') == 'presentation';

src/audits/LinkWithUnclearPurpose.js

@@ -28,15 +28,15 @@ axs.AuditRules.addRule({
      * @param {Element} element
      * @return {boolean}
      */
-    relevantElementMatcher: function(element) {
-        return axs.browserUtils.matchSelector(element, 'a[href]') && !axs.utils.isElementOrAncestorHidden(element);
+    relevantElementMatcher: function(element, flags) {
+        return axs.browserUtils.matchSelector(element, 'a[href]') && !flags.hidden;
     },
     /**
      * @param {Element} anchor
      * @param {Object=} opt_config
      * @return {boolean}
      */
-    test: function(anchor, opt_config) {
+    test: function(anchor, flags, opt_config) {
         var config = opt_config || {};
         var blacklistPhrases = config['blacklistPhrases'] || [];
         var whitespaceRE = /\s+/;

src/audits/LowContrast.js

@@ -25,9 +25,8 @@ axs.AuditRules.addRule({
     heading: 'Text elements should have a reasonable contrast ratio',
     url: 'https://github.com/GoogleChrome/accessibility-developer-tools/wiki/Audit-Rules#ax_color_01',
     severity: axs.constants.Severity.WARNING,
-    relevantElementMatcher: function(element) {
-        return axs.properties.hasDirectTextDescendant(element) &&
-            !axs.utils.isElementDisabled(element);
+    relevantElementMatcher: function(element, flags) {
+        return !flags.disabled && axs.properties.hasDirectTextDescendant(element);
     },
     test: function(element) {
         var style = window.getComputedStyle(element, null);

src/audits/MeaningfulBackgroundImage.js

@@ -22,8 +22,8 @@ goog.require('axs.utils');
 axs.AuditRules.addRule({
     name: 'elementsWithMeaningfulBackgroundImage',
     severity: axs.constants.Severity.WARNING,
-    relevantElementMatcher: function(element) {
-        return !axs.utils.isElementOrAncestorHidden(element);
+    relevantElementMatcher: function(element, flags) {
+        return !flags.hidden;
     },
     heading: 'Meaningful images should not be used in element backgrounds',
     url: 'https://github.com/GoogleChrome/accessibility-developer-tools/wiki/Audit-Rules#ax_image_01',

src/audits/NonExistentAriaRelatedElement.js

@@ -17,40 +17,27 @@ goog.require('axs.browserUtils');
 goog.require('axs.constants.Severity');
 goog.require('axs.utils');
 
-// TODO(RickSBrown): Consider expanding this beyond ARIA? e.g. 'for' on label.
-
 /**
- * 'ARIA attributes which refer to other elements by ID should refer to elements which exist in the DOM'
+ * Attributes which refer to other elements by ID should refer to elements which exist in the DOM'.
  */
 axs.AuditRules.addRule({
-    name: 'nonExistentAriaRelatedElement',
-    heading: 'ARIA attributes which refer to other elements by ID should refer to elements which exist in the DOM',
-    url: 'https://github.com/GoogleChrome/accessibility-developer-tools/wiki/Audit-Rules#ax_aria_02',
+    name: 'nonExistentRelatedElement',
+    heading: 'Attributes which refer to other elements by ID should refer to elements which exist in the DOM',
+    url: 'https://github.com/GoogleChrome/accessibility-developer-tools/wiki/Audit-Rules#ax_html_03',
     severity: axs.constants.Severity.SEVERE,
-    relevantElementMatcher: function(element) {
-        var idrefTypes = ['idref', 'idref_list'];
-        var idRefProps = axs.utils.getAriaPropertiesByValueType(idrefTypes);
-        var selector = axs.utils.getSelectorForAriaProperties(idRefProps);
-        return axs.browserUtils.matchSelector(element, selector);
+    opt_requires: {
+        idRefs: true
+    },
+    relevantElementMatcher: function(element, flags) {
+        return flags.idrefs.length > 0;
     },
-    test: function(element) {
-        var idrefTypes = ['idref', 'idref_list'];
-        var idRefProps = axs.utils.getAriaPropertiesByValueType(idrefTypes);
-        var selector = axs.utils.getSelectorForAriaProperties(idRefProps);
-        var selectors = selector.split(',');
-        for (var i = 0, len = selectors.length; i < len; i++) {
-            var nextSelector = selectors[i];
-            if (axs.browserUtils.matchSelector(element, nextSelector)) {
-                var propertyName = nextSelector.match(/aria-[^\]]+/)[0];
-                var propertyValueText = element.getAttribute(propertyName);
-                var propertyValue = axs.utils.getAriaPropertyValue(propertyName,
-                                                                   propertyValueText,
-                                                                   element);
-                if (!propertyValue.valid)
-                    return true;
-            }
-        }
-        return false;
+    test: function(element, flags) {
+        var idRefs = flags.idrefs;
+        var missing = idRefs.some(function(id) {
+            var refElement = document.getElementById(id);
+            return !refElement;
+        });
+        return missing;
     },
-    code: 'AX_ARIA_02'
+    code: 'AX_HTML_03'
 });

src/audits/RoleTooltipRequiresDescribedBy.js

@@ -25,9 +25,8 @@ axs.AuditRules.addRule({
     heading: 'Elements with role=tooltip should have a corresponding element with aria-describedby',
     url: 'https://github.com/GoogleChrome/accessibility-developer-tools/wiki/Audit-Rules#ax_aria_02',
     severity: axs.constants.Severity.SEVERE,
-    relevantElementMatcher: function(element) {
-        return axs.browserUtils.matchSelector(element, '[role=tooltip]') &&
-            !axs.utils.isElementOrAncestorHidden(element);
+    relevantElementMatcher: function(element, flags) {
+        return axs.browserUtils.matchSelector(element, '[role=tooltip]') && !flags.hidden;
     },
     test: function(element) {
         var referrers = axs.utils.getAriaIdReferrers(element, 'aria-describedby');