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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 00:47:55 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 00:47:55 +0000 |
commit | 26a029d407be480d791972afb5975cf62c9360a6 (patch) | |
tree | f435a8308119effd964b339f76abb83a57c29483 /devtools/server/actors/accessibility/audit/keyboard.js | |
parent | Initial commit. (diff) | |
download | firefox-26a029d407be480d791972afb5975cf62c9360a6.tar.xz firefox-26a029d407be480d791972afb5975cf62c9360a6.zip |
Adding upstream version 124.0.1.upstream/124.0.1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | devtools/server/actors/accessibility/audit/keyboard.js | 514 |
1 files changed, 514 insertions, 0 deletions
diff --git a/devtools/server/actors/accessibility/audit/keyboard.js b/devtools/server/actors/accessibility/audit/keyboard.js new file mode 100644 index 0000000000..d1b13dbbf6 --- /dev/null +++ b/devtools/server/actors/accessibility/audit/keyboard.js @@ -0,0 +1,514 @@ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +"use strict"; + +loader.lazyRequireGetter( + this, + "CssLogic", + "resource://devtools/server/actors/inspector/css-logic.js", + true +); +loader.lazyRequireGetter( + this, + "getCSSStyleRules", + "resource://devtools/shared/inspector/css-logic.js", + true +); +loader.lazyRequireGetter( + this, + "nodeConstants", + "resource://devtools/shared/dom-node-constants.js" +); +loader.lazyRequireGetter( + this, + ["isDefunct", "getAriaRoles"], + "resource://devtools/server/actors/utils/accessibility.js", + true +); + +const { + accessibility: { + AUDIT_TYPE: { KEYBOARD }, + ISSUE_TYPE: { + [KEYBOARD]: { + FOCUSABLE_NO_SEMANTICS, + FOCUSABLE_POSITIVE_TABINDEX, + INTERACTIVE_NO_ACTION, + INTERACTIVE_NOT_FOCUSABLE, + MOUSE_INTERACTIVE_ONLY, + NO_FOCUS_VISIBLE, + }, + }, + SCORES: { FAIL, WARNING }, + }, +} = require("resource://devtools/shared/constants.js"); + +// Specified by the author CSS rule type. +const STYLE_RULE = 1; + +// Accessible action for showing long description. +const CLICK_ACTION = "click"; + +/** + * Focus specific pseudo classes that the keyboard audit simulates to determine + * focus styling. + */ +const FOCUS_PSEUDO_CLASS = ":focus"; +const MOZ_FOCUSRING_PSEUDO_CLASS = ":-moz-focusring"; + +const KEYBOARD_FOCUSABLE_ROLES = new Set([ + Ci.nsIAccessibleRole.ROLE_BUTTONMENU, + Ci.nsIAccessibleRole.ROLE_CHECKBUTTON, + Ci.nsIAccessibleRole.ROLE_COMBOBOX, + Ci.nsIAccessibleRole.ROLE_EDITCOMBOBOX, + Ci.nsIAccessibleRole.ROLE_ENTRY, + Ci.nsIAccessibleRole.ROLE_LINK, + Ci.nsIAccessibleRole.ROLE_LISTBOX, + Ci.nsIAccessibleRole.ROLE_PASSWORD_TEXT, + Ci.nsIAccessibleRole.ROLE_PUSHBUTTON, + Ci.nsIAccessibleRole.ROLE_RADIOBUTTON, + Ci.nsIAccessibleRole.ROLE_SLIDER, + Ci.nsIAccessibleRole.ROLE_SPINBUTTON, + Ci.nsIAccessibleRole.ROLE_SUMMARY, + Ci.nsIAccessibleRole.ROLE_SWITCH, + Ci.nsIAccessibleRole.ROLE_TOGGLE_BUTTON, +]); + +const INTERACTIVE_ROLES = new Set([ + ...KEYBOARD_FOCUSABLE_ROLES, + Ci.nsIAccessibleRole.ROLE_CHECK_MENU_ITEM, + Ci.nsIAccessibleRole.ROLE_CHECK_RICH_OPTION, + Ci.nsIAccessibleRole.ROLE_COMBOBOX_OPTION, + Ci.nsIAccessibleRole.ROLE_MENUITEM, + Ci.nsIAccessibleRole.ROLE_OPTION, + Ci.nsIAccessibleRole.ROLE_OUTLINE, + Ci.nsIAccessibleRole.ROLE_OUTLINEITEM, + Ci.nsIAccessibleRole.ROLE_PAGETAB, + Ci.nsIAccessibleRole.ROLE_PARENT_MENUITEM, + Ci.nsIAccessibleRole.ROLE_RADIO_MENU_ITEM, + Ci.nsIAccessibleRole.ROLE_RICH_OPTION, +]); + +const INTERACTIVE_IF_FOCUSABLE_ROLES = new Set([ + // If article is focusable, we can assume it is inside a feed. + Ci.nsIAccessibleRole.ROLE_ARTICLE, + // Column header can be focusable. + Ci.nsIAccessibleRole.ROLE_COLUMNHEADER, + Ci.nsIAccessibleRole.ROLE_GRID_CELL, + Ci.nsIAccessibleRole.ROLE_MENUBAR, + Ci.nsIAccessibleRole.ROLE_MENUPOPUP, + Ci.nsIAccessibleRole.ROLE_PAGETABLIST, + // Row header can be focusable. + Ci.nsIAccessibleRole.ROLE_ROWHEADER, + Ci.nsIAccessibleRole.ROLE_SCROLLBAR, + Ci.nsIAccessibleRole.ROLE_SEPARATOR, + Ci.nsIAccessibleRole.ROLE_TOOLBAR, +]); + +/** + * Determine if a node is dead or is not an element node. + * + * @param {DOMNode} node + * Node to be tested for validity. + * + * @returns {Boolean} + * True if the node is either dead or is not an element node. + */ +function isInvalidNode(node) { + return ( + !node || + Cu.isDeadWrapper(node) || + node.nodeType !== nodeConstants.ELEMENT_NODE || + !node.ownerGlobal + ); +} + +/** + * Determine if accessible is focusable with the keyboard. + * + * @param {nsIAccessible} accessible + * Accessible for which to determine if it is keyboard focusable. + * + * @returns {Boolean} + * True if focusable with the keyboard. + */ +function isKeyboardFocusable(accessible) { + const state = {}; + accessible.getState(state, {}); + // State will be focusable even if the tabindex is negative. + return ( + state.value & Ci.nsIAccessibleStates.STATE_FOCUSABLE && + // Platform accessibility will still report STATE_FOCUSABLE even with the + // tabindex="-1" so we need to check that it is >= 0 to be considered + // keyboard focusable. + accessible.DOMNode.tabIndex > -1 + ); +} + +/** + * Determine if a current node has focus specific styling by applying a + * focus-related pseudo class (such as :focus or :-moz-focusring) to a focusable + * node. + * + * @param {DOMNode} focusableNode + * Node to apply focus-related pseudo class to. + * @param {DOMNode} currentNode + * Node to be checked for having focus specific styling. + * @param {String} pseudoClass + * A focus related pseudo-class to be simulated for style comparison. + * + * @returns {Boolean} + * True if the currentNode has focus specific styling. + */ +function hasStylesForFocusRelatedPseudoClass( + focusableNode, + currentNode, + pseudoClass +) { + const defaultRules = getCSSStyleRules(currentNode); + + InspectorUtils.addPseudoClassLock(focusableNode, pseudoClass); + + // Determine a set of properties that are specific to CSS rules that are only + // present when a focus related pseudo-class is locked in. + const tempRules = getCSSStyleRules(currentNode); + const properties = new Set(); + for (const rule of tempRules) { + if (rule.type !== STYLE_RULE) { + continue; + } + + if (!defaultRules.includes(rule)) { + for (let index = 0; index < rule.style.length; index++) { + properties.add(rule.style.item(index)); + } + } + } + + // If there are no focus specific CSS rules or properties, currentNode does + // node have any focus specific styling, we are done. + if (properties.size === 0) { + InspectorUtils.removePseudoClassLock(focusableNode, pseudoClass); + return false; + } + + // Determine values for properties that are focus specific. + const tempStyle = CssLogic.getComputedStyle(currentNode); + const focusStyle = {}; + for (const name of properties.values()) { + focusStyle[name] = tempStyle.getPropertyValue(name); + } + + InspectorUtils.removePseudoClassLock(focusableNode, pseudoClass); + + // If values for focus specific properties are different from default style + // values, assume we have focus spefic styles for the currentNode. + const defaultStyle = CssLogic.getComputedStyle(currentNode); + for (const name of properties.values()) { + if (defaultStyle.getPropertyValue(name) !== focusStyle[name]) { + return true; + } + } + + return false; +} + +/** + * Check if an element node (currentNode) has distinct focus styling. This + * function also takes into account a case when focus styling is applied to a + * descendant too. + * + * @param {DOMNode} focusableNode + * Node to apply focus-related pseudo class to. + * @param {DOMNode} currentNode + * Node to be checked for having focus specific styling. + * + * @returns {Boolean} + * True if the node or its descendant has distinct focus styling. + */ +function hasFocusStyling(focusableNode, currentNode) { + if (isInvalidNode(currentNode)) { + return false; + } + + // Check if an element node has distinct :-moz-focusring styling. + const hasStylesForMozFocusring = hasStylesForFocusRelatedPseudoClass( + focusableNode, + currentNode, + MOZ_FOCUSRING_PSEUDO_CLASS + ); + if (hasStylesForMozFocusring) { + return true; + } + + // Check if an element node has distinct :focus styling. + const hasStylesForFocus = hasStylesForFocusRelatedPseudoClass( + focusableNode, + currentNode, + FOCUS_PSEUDO_CLASS + ); + if (hasStylesForFocus) { + return true; + } + + // If no element specific focus styles where found, check if its element + // children have them. + for ( + let child = currentNode.firstElementChild; + child; + child = currentNode.nextnextElementSibling + ) { + if (hasFocusStyling(focusableNode, child)) { + return true; + } + } + + return false; +} + +/** + * A rule that determines if a focusable accessible object has appropriate focus + * styling. + * + * @param {nsIAccessible} accessible + * Accessible to be checked for being focusable and having focus + * styling. + * + * @return {null|Object} + * Null if accessible has keyboard focus styling, audit report object + * otherwise. + */ +function focusStyleRule(accessible) { + const { DOMNode } = accessible; + if (isInvalidNode(DOMNode)) { + return null; + } + + // Ignore non-focusable elements. + if (!isKeyboardFocusable(accessible)) { + return null; + } + + if (hasFocusStyling(DOMNode, DOMNode)) { + return null; + } + + // If no browser or author focus styling was found, check if the node is a + // widget that is themed by platform native theme. + if (InspectorUtils.isElementThemed(DOMNode)) { + return null; + } + + return { score: WARNING, issue: NO_FOCUS_VISIBLE }; +} + +/** + * A rule that determines if an interactive accessible has any associated + * accessible actions with it. If the element is interactive but and has no + * actions, assistive technology users will not be able to interact with it. + * + * @param {nsIAccessible} accessible + * Accessible to be checked for being interactive and having accessible + * actions. + * + * @return {null|Object} + * Null if accessible is not interactive or if it is and it has + * accessible action associated with it, audit report object otherwise. + */ +function interactiveRule(accessible) { + if (!INTERACTIVE_ROLES.has(accessible.role)) { + return null; + } + + if (accessible.actionCount > 0) { + return null; + } + + return { score: FAIL, issue: INTERACTIVE_NO_ACTION }; +} + +/** + * A rule that determines if an interactive accessible is also focusable when + * not disabled. + * + * @param {nsIAccessible} accessible + * Accessible to be checked for being interactive and being focusable + * when enabled. + * + * @return {null|Object} + * Null if accessible is not interactive or if it is and it is focusable + * when enabled, audit report object otherwise. + */ +function focusableRule(accessible) { + if (!KEYBOARD_FOCUSABLE_ROLES.has(accessible.role)) { + return null; + } + + const state = {}; + accessible.getState(state, {}); + // We only expect in interactive accessible object to be focusable if it is + // not disabled. + if (state.value & Ci.nsIAccessibleStates.STATE_UNAVAILABLE) { + return null; + } + + if (isKeyboardFocusable(accessible)) { + return null; + } + + const ariaRoles = getAriaRoles(accessible); + if ( + ariaRoles && + (ariaRoles.includes("combobox") || ariaRoles.includes("listbox")) + ) { + // Do not force ARIA combobox or listbox to be focusable. + return null; + } + + return { score: FAIL, issue: INTERACTIVE_NOT_FOCUSABLE }; +} + +/** + * A rule that determines if a focusable accessible has an associated + * interactive role. + * + * @param {nsIAccessible} accessible + * Accessible to be checked for having an interactive role if it is + * focusable. + * + * @return {null|Object} + * Null if accessible is not interactive or if it is and it has an + * interactive role, audit report object otherwise. + */ +function semanticsRule(accessible) { + if ( + INTERACTIVE_ROLES.has(accessible.role) || + // Visible listboxes will have focusable state when inside comboboxes. + accessible.role === Ci.nsIAccessibleRole.ROLE_COMBOBOX_LIST + ) { + return null; + } + + if (isKeyboardFocusable(accessible)) { + if (INTERACTIVE_IF_FOCUSABLE_ROLES.has(accessible.role)) { + return null; + } + + // ROLE_TABLE is used for grids too which are considered interactive. + if (accessible.role === Ci.nsIAccessibleRole.ROLE_TABLE) { + const ariaRoles = getAriaRoles(accessible); + if (ariaRoles && ariaRoles.includes("grid")) { + return null; + } + } + + return { score: WARNING, issue: FOCUSABLE_NO_SEMANTICS }; + } + + const state = {}; + accessible.getState(state, {}); + if ( + // Ignore text leafs. + accessible.role === Ci.nsIAccessibleRole.ROLE_TEXT_LEAF || + // Ignore accessibles with no accessible actions. + accessible.actionCount === 0 || + // Ignore labels that have a label for relation with their target because + // they are clickable. + (accessible.role === Ci.nsIAccessibleRole.ROLE_LABEL && + accessible.getRelationByType(Ci.nsIAccessibleRelation.RELATION_LABEL_FOR) + .targetsCount > 0) || + // Ignore images that are inside an anchor (have linked state). + (accessible.role === Ci.nsIAccessibleRole.ROLE_GRAPHIC && + state.value & Ci.nsIAccessibleStates.STATE_LINKED) + ) { + return null; + } + + // Ignore anything but a click action in the list of actions. + for (let i = 0; i < accessible.actionCount; i++) { + if (accessible.getActionName(i) === CLICK_ACTION) { + return { score: FAIL, issue: MOUSE_INTERACTIVE_ONLY }; + } + } + + return null; +} + +/** + * A rule that determines if an element associated with a focusable accessible + * has a positive tabindex. + * + * @param {nsIAccessible} accessible + * Accessible to be checked for having an element with positive tabindex + * attribute. + * + * @return {null|Object} + * Null if accessible is not focusable or if it is and its element's + * tabindex attribute is less than 1, audit report object otherwise. + */ +function tabIndexRule(accessible) { + const { DOMNode } = accessible; + if (isInvalidNode(DOMNode)) { + return null; + } + + if (!isKeyboardFocusable(accessible)) { + return null; + } + + if (DOMNode.tabIndex > 0) { + return { score: WARNING, issue: FOCUSABLE_POSITIVE_TABINDEX }; + } + + return null; +} + +function auditKeyboard(accessible) { + if (isDefunct(accessible)) { + return null; + } + // Do not test anything on accessible objects for documents or frames. + if ( + accessible.role === Ci.nsIAccessibleRole.ROLE_DOCUMENT || + accessible.role === Ci.nsIAccessibleRole.ROLE_INTERNAL_FRAME + ) { + return null; + } + + // Check if interactive accessible can be used by the assistive + // technology. + let issue = interactiveRule(accessible); + if (issue) { + return issue; + } + + // Check if interactive accessible is also focusable when enabled. + issue = focusableRule(accessible); + if (issue) { + return issue; + } + + // Check if accessible object has an element with a positive tabindex. + issue = tabIndexRule(accessible); + if (issue) { + return issue; + } + + // Check if a focusable accessible has interactive semantics. + issue = semanticsRule(accessible); + if (issue) { + return issue; + } + + // Check if focusable accessible has associated focus styling. + issue = focusStyleRule(accessible); + if (issue) { + return issue; + } + + return issue; +} + +module.exports.auditKeyboard = auditKeyboard; 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