ladybird/Libraries/LibWeb/ARIA/ARIAMixin.cpp
sideshowbarker 10766ecf54 LibWeb: Ignore role=none for focusable & has-global-ARIA-attribute cases
This change causes explicit role=none and role=presentation attribute
values to be ignored in cases where the elements for which those values
are specified are either focusable, or have global ARIA attributes —
per https://w3c.github.io/aria/#conflict_resolution_presentation_none.
2025-01-09 14:08:23 +00:00

225 lines
11 KiB
C++

/*
* Copyright (c) 2022, Jonah Shafran <jonahshafran@gmail.com>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <LibWeb/ARIA/ARIAMixin.h>
#include <LibWeb/ARIA/Roles.h>
#include <LibWeb/DOM/Element.h>
#include <LibWeb/Infra/CharacterTypes.h>
namespace Web::ARIA {
// https://www.w3.org/TR/wai-aria-1.2/#introroles
Optional<Role> ARIAMixin::role_from_role_attribute_value() const
{
// 1. Use the rules of the host language to detect that an element has a role attribute and to identify the attribute value string for it.
auto maybe_role_string = role();
if (!maybe_role_string.has_value())
return OptionalNone {};
// 2. Separate the attribute value string for that attribute into a sequence of whitespace-free substrings by separating on whitespace.
auto role_string = maybe_role_string.value();
auto role_list = role_string.bytes_as_string_view().split_view_if(Infra::is_ascii_whitespace);
// 3. Compare the substrings to all the names of the non-abstract WAI-ARIA roles. Case-sensitivity of the comparison inherits from the case-sensitivity of the host language.
for (auto const& role_name : role_list) {
auto role = role_from_string(role_name);
if (!role.has_value())
continue;
// NOTE: Per https://w3c.github.io/aria/#directory, "Authors are advised to treat directory as deprecated and to
// use 'list'." Further, the "directory role == computedrole list" and "div w/directory role == computedrole
// list" tests in https://wpt.fyi/results/wai-aria/role/synonym-roles.html expect "list", not "directory".
if (role == Role::directory)
return Role::list;
// NOTE: The "image" role value is a synonym for the older "img" role value; however, the "synonym img role ==
// computedrole image" test in https://wpt.fyi/results/wai-aria/role/synonym-roles.html expects "image", not "img".
if (role == Role::img)
return Role::image;
// https://w3c.github.io/core-aam/#roleMappingComputedRole
// When an element has a role but is not contained in the required context (for example, an orphaned listitem
// without the required accessible parent of role list), User Agents MUST ignore the role token, and return the
// computedrole as if the ignored role token had not been included.
if (role == ARIA::Role::columnheader) {
for (auto const* ancestor = to_element()->parent_element(); ancestor; ancestor = ancestor->parent_element()) {
if (ancestor->role_or_default() == ARIA::Role::row)
return ARIA::Role::columnheader;
}
continue;
}
if (role == ARIA::Role::gridcell) {
for (auto const* ancestor = to_element()->parent_element(); ancestor; ancestor = ancestor->parent_element()) {
if (ancestor->role_or_default() == ARIA::Role::row)
return ARIA::Role::gridcell;
}
continue;
}
if (role == ARIA::Role::listitem) {
for (auto const* ancestor = to_element()->parent_element(); ancestor; ancestor = ancestor->parent_element()) {
if (first_is_one_of(ancestor->role_or_default(), ARIA::Role::directory, ARIA::Role::list))
return ARIA::Role::listitem;
}
continue;
}
if (role == ARIA::Role::menuitem) {
for (auto const* ancestor = to_element()->parent_element(); ancestor; ancestor = ancestor->parent_element()) {
if (first_is_one_of(ancestor->role_or_default(), ARIA::Role::menu, ARIA::Role::menubar))
return ARIA::Role::menuitem;
}
continue;
}
if (role == ARIA::Role::menuitemcheckbox) {
for (auto const* ancestor = to_element()->parent_element(); ancestor; ancestor = ancestor->parent_element()) {
if (first_is_one_of(ancestor->role_or_default(), ARIA::Role::menu, ARIA::Role::menubar))
return ARIA::Role::menuitemcheckbox;
}
continue;
}
if (role == ARIA::Role::menuitemradio) {
for (auto const* ancestor = to_element()->parent_element(); ancestor; ancestor = ancestor->parent_element()) {
if (first_is_one_of(ancestor->role_or_default(), ARIA::Role::menu, ARIA::Role::menubar))
return ARIA::Role::menuitemradio;
}
continue;
}
if (role == ARIA::Role::option) {
for (auto const* ancestor = to_element()->parent_element(); ancestor; ancestor = ancestor->parent_element()) {
if (ancestor->role_or_default() == ARIA::Role::listbox)
return ARIA::Role::option;
}
continue;
}
if (role == ARIA::Role::row) {
for (auto const* ancestor = to_element()->parent_element(); ancestor; ancestor = ancestor->parent_element()) {
if (first_is_one_of(ancestor->role_or_default(), ARIA::Role::table, ARIA::Role::grid, ARIA::Role::treegrid))
return ARIA::Role::row;
}
continue;
}
if (role == ARIA::Role::rowgroup) {
for (auto const* ancestor = to_element()->parent_element(); ancestor; ancestor = ancestor->parent_element()) {
if (first_is_one_of(ancestor->role_or_default(), ARIA::Role::table, ARIA::Role::grid, ARIA::Role::treegrid))
return ARIA::Role::rowgroup;
}
continue;
}
if (role == ARIA::Role::rowheader) {
for (auto const* ancestor = to_element()->parent_element(); ancestor; ancestor = ancestor->parent_element()) {
if (ancestor->role_or_default() == ARIA::Role::row)
return ARIA::Role::rowheader;
}
continue;
}
if (role == ARIA::Role::tab) {
for (auto const* ancestor = to_element()->parent_element(); ancestor; ancestor = ancestor->parent_element()) {
if (ancestor->role_or_default() == ARIA::Role::tablist)
return ARIA::Role::tab;
}
continue;
}
if (role == ARIA::Role::treeitem) {
for (auto const* ancestor = to_element()->parent_element(); ancestor; ancestor = ancestor->parent_element()) {
if (ancestor->role_or_default() == ARIA::Role::tree)
return ARIA::Role::treeitem;
}
continue;
}
// https://w3c.github.io/aria/#document-handling_author-errors_roles
// Certain landmark roles require names from authors. In situations where an author has not specified names for
// these landmarks, it is considered an authoring error. The user agent MUST treat such elements as if no role
// had been provided. If a valid fallback role had been specified, or if the element had an implicit ARIA role,
// then user agents would continue to expose that role, instead.
if ((role == ARIA::Role::form || role == ARIA::Role::region)
&& to_element()->accessible_name(to_element()->document(), DOM::ShouldComputeRole::No).value().is_empty())
continue;
if (role == ARIA::Role::none || role == ARIA::Role::presentation) {
// https://w3c.github.io/aria/#conflict_resolution_presentation_none
// If an element is focusable, user agents MUST ignore the none/presentation
// role and expose the element with its implicit role.
if (to_element()->is_focusable())
continue;
// If an element has global WAI-ARIA states or properties, user agents MUST
// ignore the none/presentation role and instead expose the element's implicit role.
if (has_global_aria_attribute())
continue;
// NOTE: Per https://w3c.github.io/aria/#presentation, "the working group introduced 'none' as the preferred
// synonym to the presentation role"; further, https://wpt.fyi/results/wai-aria/role/synonym-roles.html has
// a "synonym presentation role == computedrole none" test that expects "none", not "presentation".
if (role == Role::presentation)
return Role::none;
}
// 4. Use the first such substring in textual order that matches the name of a non-abstract WAI-ARIA role.
if (!is_abstract_role(*role))
return *role;
}
// https://www.w3.org/TR/wai-aria-1.2/#document-handling_author-errors_roles
// If the role attribute contains no tokens matching the name of a non-abstract WAI-ARIA role, the user agent MUST treat the element as if no role had been provided.
// https://www.w3.org/TR/wai-aria-1.2/#implicit_semantics
return OptionalNone {};
}
Optional<Role> ARIAMixin::role_or_default() const
{
if (auto role = role_from_role_attribute_value(); role.has_value())
return role;
return default_role();
}
// https://www.w3.org/TR/wai-aria-1.2/#global_states
bool ARIAMixin::has_global_aria_attribute() const
{
return aria_atomic().has_value()
|| aria_braille_label().has_value()
|| aria_braille_role_description().has_value()
|| aria_busy().has_value()
|| aria_controls().has_value()
|| aria_current().has_value()
|| aria_described_by().has_value()
|| aria_description().has_value()
|| aria_details().has_value()
|| aria_disabled().has_value()
|| aria_drop_effect().has_value()
|| aria_error_message().has_value()
|| aria_flow_to().has_value()
|| aria_grabbed().has_value()
|| aria_has_popup().has_value()
|| aria_hidden().has_value()
|| aria_invalid().has_value()
|| aria_key_shortcuts().has_value()
|| aria_label().has_value()
|| aria_labelled_by().has_value()
|| aria_live().has_value()
|| aria_owns().has_value()
|| aria_relevant().has_value()
|| aria_role_description().has_value();
}
Optional<String> ARIAMixin::parse_id_reference(Optional<String> const& id_reference) const
{
if (!id_reference.has_value())
return {};
if (id_reference_exists(id_reference.value()))
return id_reference.value();
return {};
}
Vector<String> ARIAMixin::parse_id_reference_list(Optional<String> const& id_list) const
{
Vector<String> result;
if (!id_list.has_value())
return result;
auto id_references = id_list->bytes_as_string_view().split_view_if(Infra::is_ascii_whitespace);
for (auto const id_reference_view : id_references) {
auto id_reference = MUST(String::from_utf8(id_reference_view));
if (id_reference_exists(id_reference))
result.append(id_reference);
}
return result;
}
}