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/*
* Copyright (C) 2008 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "third_party/blink/renderer/modules/accessibility/ax_layout_object.h"
#include "third_party/blink/renderer/core/aom/accessible_node.h"
#include "third_party/blink/renderer/core/css/css_property_names.h"
#include "third_party/blink/renderer/core/dom/element_traversal.h"
#include "third_party/blink/renderer/core/dom/range.h"
#include "third_party/blink/renderer/core/dom/shadow_root.h"
#include "third_party/blink/renderer/core/editing/editing_utilities.h"
#include "third_party/blink/renderer/core/editing/ephemeral_range.h"
#include "third_party/blink/renderer/core/editing/frame_selection.h"
#include "third_party/blink/renderer/core/editing/iterators/character_iterator.h"
#include "third_party/blink/renderer/core/editing/iterators/text_iterator.h"
#include "third_party/blink/renderer/core/editing/selection_template.h"
#include "third_party/blink/renderer/core/editing/text_affinity.h"
#include "third_party/blink/renderer/core/editing/visible_position.h"
#include "third_party/blink/renderer/core/editing/visible_selection.h"
#include "third_party/blink/renderer/core/editing/visible_units.h"
#include "third_party/blink/renderer/core/frame/frame_owner.h"
#include "third_party/blink/renderer/core/frame/local_frame.h"
#include "third_party/blink/renderer/core/frame/local_frame_view.h"
#include "third_party/blink/renderer/core/frame/settings.h"
#include "third_party/blink/renderer/core/html/canvas/html_canvas_element.h"
#include "third_party/blink/renderer/core/html/canvas/image_data.h"
#include "third_party/blink/renderer/core/html/forms/html_input_element.h"
#include "third_party/blink/renderer/core/html/forms/html_label_element.h"
#include "third_party/blink/renderer/core/html/forms/html_option_element.h"
#include "third_party/blink/renderer/core/html/forms/html_select_element.h"
#include "third_party/blink/renderer/core/html/forms/html_text_area_element.h"
#include "third_party/blink/renderer/core/html/forms/labels_node_list.h"
#include "third_party/blink/renderer/core/html/html_frame_owner_element.h"
#include "third_party/blink/renderer/core/html/html_image_element.h"
#include "third_party/blink/renderer/core/html/html_table_caption_element.h"
#include "third_party/blink/renderer/core/html/html_table_cell_element.h"
#include "third_party/blink/renderer/core/html/html_table_col_element.h"
#include "third_party/blink/renderer/core/html/html_table_element.h"
#include "third_party/blink/renderer/core/html/media/html_video_element.h"
#include "third_party/blink/renderer/core/html/shadow/shadow_element_names.h"
#include "third_party/blink/renderer/core/imagebitmap/image_bitmap.h"
#include "third_party/blink/renderer/core/imagebitmap/image_bitmap_options.h"
#include "third_party/blink/renderer/core/input_type_names.h"
#include "third_party/blink/renderer/core/layout/api/line_layout_api_shim.h"
#include "third_party/blink/renderer/core/layout/hit_test_result.h"
#include "third_party/blink/renderer/core/layout/layout_file_upload_control.h"
#include "third_party/blink/renderer/core/layout/layout_html_canvas.h"
#include "third_party/blink/renderer/core/layout/layout_image.h"
#include "third_party/blink/renderer/core/layout/layout_inline.h"
#include "third_party/blink/renderer/core/layout/layout_list_item.h"
#include "third_party/blink/renderer/core/layout/layout_list_marker.h"
#include "third_party/blink/renderer/core/layout/layout_menu_list.h"
#include "third_party/blink/renderer/core/layout/layout_table.h"
#include "third_party/blink/renderer/core/layout/layout_table_cell.h"
#include "third_party/blink/renderer/core/layout/layout_table_row.h"
#include "third_party/blink/renderer/core/layout/layout_table_section.h"
#include "third_party/blink/renderer/core/layout/layout_text_control.h"
#include "third_party/blink/renderer/core/layout/layout_text_fragment.h"
#include "third_party/blink/renderer/core/layout/layout_view.h"
#include "third_party/blink/renderer/core/layout/ng/inline/ng_inline_node.h"
#include "third_party/blink/renderer/core/layout/ng/list/layout_ng_list_item.h"
#include "third_party/blink/renderer/core/layout/ng/list/layout_ng_list_marker.h"
#include "third_party/blink/renderer/core/loader/progress_tracker.h"
#include "third_party/blink/renderer/core/page/page.h"
#include "third_party/blink/renderer/core/paint/ng/ng_paint_fragment.h"
#include "third_party/blink/renderer/core/paint/ng/ng_paint_fragment_traversal.h"
#include "third_party/blink/renderer/core/paint/paint_layer.h"
#include "third_party/blink/renderer/core/paint/paint_layer_scrollable_area.h"
#include "third_party/blink/renderer/core/style/computed_style_constants.h"
#include "third_party/blink/renderer/core/svg/graphics/svg_image.h"
#include "third_party/blink/renderer/core/svg/svg_document_extensions.h"
#include "third_party/blink/renderer/core/svg/svg_svg_element.h"
#include "third_party/blink/renderer/modules/accessibility/ax_image_map_link.h"
#include "third_party/blink/renderer/modules/accessibility/ax_inline_text_box.h"
#include "third_party/blink/renderer/modules/accessibility/ax_mock_object.h"
#include "third_party/blink/renderer/modules/accessibility/ax_object_cache_impl.h"
#include "third_party/blink/renderer/modules/accessibility/ax_svg_root.h"
#include "third_party/blink/renderer/platform/bindings/exception_state.h"
#include "third_party/blink/renderer/platform/graphics/image_data_buffer.h"
#include "third_party/blink/renderer/platform/text/platform_locale.h"
#include "third_party/blink/renderer/platform/text/text_direction.h"
#include "third_party/blink/renderer/platform/transforms/transform_state.h"
#include "third_party/blink/renderer/platform/wtf/std_lib_extras.h"
using blink::WebLocalizedString;
namespace blink {
using namespace html_names;
AXLayoutObject::AXLayoutObject(LayoutObject* layout_object,
AXObjectCacheImpl& ax_object_cache)
: AXNodeObject(layout_object->GetNode(), ax_object_cache),
layout_object_(layout_object),
is_autofill_available_(false) {
// TODO(aleventhal) Get correct current state of autofill.
#if DCHECK_IS_ON()
layout_object_->SetHasAXObject(true);
#endif
}
AXLayoutObject* AXLayoutObject::Create(LayoutObject* layout_object,
AXObjectCacheImpl& ax_object_cache) {
return MakeGarbageCollected<AXLayoutObject>(layout_object, ax_object_cache);
}
AXLayoutObject::~AXLayoutObject() {
DCHECK(IsDetached());
}
LayoutBoxModelObject* AXLayoutObject::GetLayoutBoxModelObject() const {
if (!layout_object_ || !layout_object_->IsBoxModelObject())
return nullptr;
return ToLayoutBoxModelObject(layout_object_);
}
bool IsProgrammaticallyScrollable(LayoutBox* box) {
if (!box->HasOverflowClip()) {
// If overflow is visible it is not scrollable.
return false;
}
// Return true if the content is larger than the available space.
return box->PixelSnappedScrollWidth() != box->PixelSnappedClientWidth() ||
box->PixelSnappedScrollHeight() != box->PixelSnappedClientHeight();
}
ScrollableArea* AXLayoutObject::GetScrollableAreaIfScrollable() const {
if (IsWebArea())
return DocumentFrameView()->LayoutViewport();
if (!layout_object_ || !layout_object_->IsBox())
return nullptr;
LayoutBox* box = ToLayoutBox(layout_object_);
// This should possibly use box->CanBeScrolledAndHasScrollableArea() as it
// used to; however, accessibility must consider any kind of non-visible
// overflow as programmatically scrollable. Unfortunately
// LayoutBox::CanBeScrolledAndHasScrollableArea() method calls
// LayoutBox::CanBeProgramaticallyScrolled() which does not consider
// visibility:hidden content to be programmatically scrollable, although it
// certainly is, and can even be scrolled by selecting and using shift+arrow
// keys. It should be noticed that the new code used here reduces the overall
// amount of work as well.
// It is not sufficient to expose it only in the anoymous child, because that
// child is truncated in platform accessibility trees, which present the
// textfield as a leaf.
ScrollableArea* scrollable_area = box->GetScrollableArea();
if (scrollable_area && IsProgrammaticallyScrollable(box))
return scrollable_area;
return nullptr;
}
static bool IsImageOrAltText(LayoutBoxModelObject* box, Node* node) {
if (box && box->IsImage())
return true;
if (IsHTMLImageElement(node))
return true;
if (IsHTMLInputElement(node) &&
ToHTMLInputElement(node)->HasFallbackContent())
return true;
return false;
}
ax::mojom::Role AXLayoutObject::NativeRoleIgnoringAria() const {
Node* node = layout_object_->GetNode();
LayoutBoxModelObject* css_box = GetLayoutBoxModelObject();
if ((css_box && css_box->IsListItem()) || IsHTMLLIElement(node))
return ax::mojom::Role::kListItem;
if (layout_object_->IsListMarkerIncludingNG())
return ax::mojom::Role::kListMarker;
if (layout_object_->IsBR())
return ax::mojom::Role::kLineBreak;
if (layout_object_->IsText())
return ax::mojom::Role::kStaticText;
if (layout_object_->IsTable() && node) {
return IsDataTable() ? ax::mojom::Role::kTable
: ax::mojom::Role::kLayoutTable;
}
if (layout_object_->IsTableRow() && node)
return DetermineTableRowRole();
if (layout_object_->IsTableCell() && node)
return DetermineTableCellRole();
if (css_box && IsImageOrAltText(css_box, node)) {
if (node && node->IsLink())
return ax::mojom::Role::kImageMap;
if (IsHTMLInputElement(node))
return ButtonRoleType();
if (IsSVGImage())
return ax::mojom::Role::kSvgRoot;
return ax::mojom::Role::kImage;
}
if (IsHTMLCanvasElement(node))
return ax::mojom::Role::kCanvas;
if (css_box && css_box->IsLayoutView())
return ax::mojom::Role::kRootWebArea;
if (layout_object_->IsSVGImage())
return ax::mojom::Role::kImage;
if (layout_object_->IsSVGRoot())
return ax::mojom::Role::kSvgRoot;
// Table sections should be ignored if there is no reason not to, e.g.
// ARIA 1.2 (and Core-AAM 1.1) state that elements which are focusable
// and not hidden must be included in the accessibility tree.
if (layout_object_->IsTableSection()) {
if (CanSetFocusAttribute())
return ax::mojom::Role::kGroup;
return ax::mojom::Role::kIgnored;
}
if (layout_object_->IsHR())
return ax::mojom::Role::kSplitter;
return AXNodeObject::NativeRoleIgnoringAria();
}
ax::mojom::Role AXLayoutObject::DetermineAccessibilityRole() {
if (!layout_object_)
return ax::mojom::Role::kUnknown;
native_role_ = NativeRoleIgnoringAria();
if ((aria_role_ = DetermineAriaRoleAttribute()) != ax::mojom::Role::kUnknown)
return aria_role_;
// Anything that needs to still be exposed but doesn't have a more specific
// role should be considered a generic container. Examples are
// layout blocks with no node, in-page link targets, and plain elements
// such as a <span> with ARIA markup.
return native_role_ == ax::mojom::Role::kUnknown
? ax::mojom::Role::kGenericContainer
: native_role_;
}
Node* AXLayoutObject::GetNodeOrContainingBlockNode() const {
if (IsDetached())
return nullptr;
if (layout_object_->IsListMarker())
return ToLayoutListMarker(layout_object_)->ListItem()->GetNode();
if (layout_object_->IsLayoutNGListMarker())
return ToLayoutNGListMarker(layout_object_)->ListItem()->GetNode();
if (layout_object_->IsAnonymousBlock() && layout_object_->ContainingBlock()) {
return layout_object_->ContainingBlock()->GetNode();
}
return GetNode();
}
void AXLayoutObject::Init() {
AXNodeObject::Init();
}
void AXLayoutObject::Detach() {
AXNodeObject::Detach();
DetachRemoteSVGRoot();
#if DCHECK_IS_ON()
if (layout_object_)
layout_object_->SetHasAXObject(false);
#endif
layout_object_ = nullptr;
}
//
// Check object role or purpose.
//
static bool IsLinkable(const AXObject& object) {
if (!object.GetLayoutObject())
return false;
// See https://wiki.mozilla.org/Accessibility/AT-Windows-API for the elements
// Mozilla considers linkable.
return object.IsLink() || object.IsImage() ||
object.GetLayoutObject()->IsText();
}
bool AXLayoutObject::IsDefault() const {
if (IsDetached())
return false;
// Checks for any kind of disabled, including aria-disabled.
if (Restriction() == kRestrictionDisabled ||
RoleValue() != ax::mojom::Role::kButton)
return false;
// Will only match :default pseudo class if it's the first default button in
// a form.
return GetElement()->MatchesDefaultPseudoClass();
}
// Requires layoutObject to be present because it relies on style
// user-modify. Don't move this logic to AXNodeObject.
bool AXLayoutObject::IsEditable() const {
if (IsDetached())
return false;
const Node* node = GetNodeOrContainingBlockNode();
if (!node)
return false;
// TODO(accessibility) pursue standards track so that aria-goog-editable
// becomes aria-editable. At that time, create ariaEditableAttr in
// html_element.cc. The current version of the editable attribute does not
// inherit, in order to match the automatic Gecko implementation, but
// hopefully the standardized version will, in which case a more performant
// implementation will be required, e.g. cache it or only expose on ancestor,
// having browser-side propagate it.
const Element* elem = node->IsElementNode()
? ToElement(node)
: FlatTreeTraversal::ParentElement(*node);
if (elem && elem->hasAttribute("aria-goog-editable")) {
auto editable = elem->getAttribute("aria-goog-editable");
return !EqualIgnoringASCIICase("false", editable);
}
if (GetLayoutObject()->IsTextControl())
return true;
// Contrary to Firefox, we mark editable all auto-generated content, such as
// list bullets and soft line breaks, that are contained within an editable
// container.
if (HasEditableStyle(*node))
return true;
if (IsWebArea()) {
Document& document = GetLayoutObject()->GetDocument();
HTMLElement* body = document.body();
if (body && HasEditableStyle(*body)) {
AXObject* ax_body = AXObjectCache().GetOrCreate(body);
return ax_body && ax_body != ax_body->AriaHiddenRoot();
}
return HasEditableStyle(document);
}
return AXNodeObject::IsEditable();
}
// Requires layoutObject to be present because it relies on style
// user-modify. Don't move this logic to AXNodeObject.
bool AXLayoutObject::IsRichlyEditable() const {
if (IsDetached())
return false;
const Node* node = GetNodeOrContainingBlockNode();
if (!node)
return false;
// TODO(accessibility) pursue standards track so that aria-goog-editable
// becomes aria-editable. At that time, create ariaEditableAttr in
// html_element.cc. The current version of the editable attribute does not
// inherit, in order to match the automatic Gecko implementation, but
// hopefully the standardized version will, in which case a more performant
// implementation will be required, e.g. cache it or only expose on ancestor,
// having browser-side propagate it.
const Element* elem = node->IsElementNode()
? ToElement(node)
: FlatTreeTraversal::ParentElement(*node);
if (elem && elem->hasAttribute("aria-goog-editable")) {
auto editable = elem->getAttribute("aria-goog-editable");
return !EqualIgnoringASCIICase("false", editable);
}
// Contrary to Firefox, we mark richly editable all auto-generated content,
// such as list bullets and soft line breaks, that are contained within a
// richly editable container.
if (HasRichlyEditableStyle(*node))
return true;
if (IsWebArea()) {
Document& document = layout_object_->GetDocument();
HTMLElement* body = document.body();
if (body && HasRichlyEditableStyle(*body)) {
AXObject* ax_body = AXObjectCache().GetOrCreate(body);
return ax_body && ax_body != ax_body->AriaHiddenRoot();
}
return HasRichlyEditableStyle(document);
}
return AXNodeObject::IsRichlyEditable();
}
bool AXLayoutObject::IsLinked() const {
if (!IsLinkable(*this))
return false;
if (auto* anchor = ToHTMLAnchorElementOrNull(AnchorElement()))
return !anchor->Href().IsEmpty();
return false;
}
bool AXLayoutObject::IsLoaded() const {
return !layout_object_->GetDocument().Parser();
}
bool AXLayoutObject::IsOffScreen() const {
DCHECK(layout_object_);
IntRect content_rect =
PixelSnappedIntRect(layout_object_->VisualRectInDocument());
LocalFrameView* view = layout_object_->GetFrame()->View();
IntRect view_rect(IntPoint(), view->Size());
view_rect.Intersect(content_rect);
return view_rect.IsEmpty();
}
bool AXLayoutObject::IsVisited() const {
// FIXME: Is it a privacy violation to expose visited information to
// accessibility APIs?
return layout_object_->Style()->IsLink() &&
layout_object_->Style()->InsideLink() ==
EInsideLink::kInsideVisitedLink;
}
//
// Check object state.
//
bool AXLayoutObject::IsFocused() const {
if (!GetDocument())
return false;
Element* focused_element = GetDocument()->FocusedElement();
if (!focused_element)
return false;
AXObject* focused_object = AXObjectCache().GetOrCreate(focused_element);
if (!focused_object || !focused_object->IsAXLayoutObject())
return false;
// A web area is represented by the Document node in the DOM tree, which isn't
// focusable. Check instead if the frame's selection controller is focused
if (focused_object == this ||
(RoleValue() == ax::mojom::Role::kRootWebArea &&
GetDocument()->GetFrame()->Selection().FrameIsFocusedAndActive()))
return true;
return false;
}
AccessibilitySelectedState AXLayoutObject::IsSelected() const {
if (!GetLayoutObject() || !GetNode() || !CanSetSelectedAttribute())
return kSelectedStateUndefined;
// aria-selected overrides automatic behaviors
bool is_selected;
if (HasAOMPropertyOrARIAAttribute(AOMBooleanProperty::kSelected, is_selected))
return is_selected ? kSelectedStateTrue : kSelectedStateFalse;
// Tab item with focus in the associated tab
if (IsTabItem() && IsTabItemSelected())
return kSelectedStateTrue;
// Selection follows focus, but ONLY in single selection containers,
// and only if aria-selected was not present to override
return IsSelectedFromFocus() ? kSelectedStateTrue : kSelectedStateFalse;
}
// In single selection containers, selection follows focus unless aria_selected
// is set to false.
bool AXLayoutObject::IsSelectedFromFocus() const {
// If not a single selection container, selection does not follow focus.
AXObject* container = ContainerWidget();
if (!container || container->IsMultiSelectable())
return false;
// If this object is not accessibility focused, then it is not selected from
// focus.
AXObject* focused_object = AXObjectCache().FocusedObject();
if (focused_object != this &&
(!focused_object || focused_object->ActiveDescendant() != this))
return false;
// In single selection container and accessibility focused => true if
// aria-selected wasn't used as an override.
bool is_selected;
return !HasAOMPropertyOrARIAAttribute(AOMBooleanProperty::kSelected,
is_selected);
}
//
// Whether objects are ignored, i.e. not included in the tree.
//
AXObjectInclusion AXLayoutObject::DefaultObjectInclusion(
IgnoredReasons* ignored_reasons) const {
// The following cases can apply to any element that's a subclass of
// AXLayoutObject.
if (!layout_object_) {
if (ignored_reasons)
ignored_reasons->push_back(IgnoredReason(kAXNotRendered));
return kIgnoreObject;
}
if (layout_object_->Style()->Visibility() != EVisibility::kVisible) {
// aria-hidden is meant to override visibility as the determinant in AX
// hierarchy inclusion.
if (AOMPropertyOrARIAAttributeIsFalse(AOMBooleanProperty::kHidden))
return kDefaultBehavior;
if (ignored_reasons)
ignored_reasons->push_back(IgnoredReason(kAXNotVisible));
return kIgnoreObject;
}
return AXObject::DefaultObjectInclusion(ignored_reasons);
}
bool HasAriaAttribute(Element* element) {
if (!element)
return false;
AttributeCollection attributes = element->AttributesWithoutUpdate();
for (const Attribute& attr : attributes) {
// Attributes cache their uppercase names.
if (attr.GetName().LocalNameUpper().StartsWith("ARIA-"))
return true;
}
return false;
}
static bool HasLineBox(const LayoutBlockFlow& block_flow) {
if (!block_flow.IsLayoutNGMixin())
return block_flow.FirstLineBox();
if (block_flow.HasNGInlineNodeData())
return !block_flow.GetNGInlineNodeData()->items.IsEmpty();
// TODO(layout-dev): We should call this function after layout completion.
return false;
}
// Is this the anonymous placeholder for a text control?
bool AXLayoutObject::IsPlaceholder() const {
AXObject* parent_object = ParentObject();
if (!parent_object)
return false;
LayoutObject* parent_layout_object = parent_object->GetLayoutObject();
if (!parent_layout_object || !parent_layout_object->IsTextControl())
return false;
LayoutTextControl* layout_text_control =
ToLayoutTextControl(parent_layout_object);
DCHECK(layout_text_control);
TextControlElement* text_control_element =
layout_text_control->GetTextControlElement();
if (!text_control_element)
return false;
HTMLElement* placeholder_element = text_control_element->PlaceholderElement();
return GetElement() == static_cast<Element*>(placeholder_element);
}
bool AXLayoutObject::ComputeAccessibilityIsIgnored(
IgnoredReasons* ignored_reasons) const {
#if DCHECK_IS_ON()
DCHECK(initialized_);
#endif
if (!layout_object_)
return true;
// Check first if any of the common reasons cause this element to be ignored.
// Then process other use cases that need to be applied to all the various
// roles that AXLayoutObjects take on.
AXObjectInclusion decision = DefaultObjectInclusion(ignored_reasons);
if (decision == kIncludeObject)
return false;
if (decision == kIgnoreObject)
return true;
if (layout_object_->IsAnonymousBlock() && !IsEditable())
return true;
// Ignore continuations, since those are essentially duplicate copies
// of inline nodes with blocks inside.
if (layout_object_->IsElementContinuation())
return true;
// If this element is within a parent that cannot have children, it should not
// be exposed.
if (IsDescendantOfLeafNode()) {
if (ignored_reasons) {
ignored_reasons->push_back(
IgnoredReason(kAXAncestorIsLeafNode, LeafNodeAncestor()));
}
return true;
}
if (RoleValue() == ax::mojom::Role::kIgnored) {
if (ignored_reasons)
ignored_reasons->push_back(IgnoredReason(kAXUninteresting));
return true;
}
if (HasInheritedPresentationalRole()) {
if (ignored_reasons) {
const AXObject* inherits_from = InheritsPresentationalRoleFrom();
if (inherits_from == this) {
ignored_reasons->push_back(IgnoredReason(kAXPresentational));
} else {
ignored_reasons->push_back(
IgnoredReason(kAXInheritsPresentation, inherits_from));
}
}
return true;
}
if (IsTableLikeRole() || IsTableRowLikeRole() || IsTableCellLikeRole())
return false;
// A LayoutEmbeddedContent is an iframe element or embedded object element or
// something like that. We don't want to ignore those.
if (layout_object_->IsLayoutEmbeddedContent())
return false;
// Make sure renderers with layers stay in the tree.
if (GetLayoutObject() && GetLayoutObject()->HasLayer() && GetNode() &&
GetNode()->hasChildren()) {
if (IsPlaceholder()) {
// Placeholder is already exposed via AX attributes, do not expose as
// child of text input. Therefore, if there is a child of a text input,
// it will contain the value.
if (ignored_reasons)
ignored_reasons->push_back(IgnoredReason(kAXPresentational));
return true;
}
return false;
}
// Find out if this element is inside of a label element. If so, it may be
// ignored because it's the label for a checkbox or radio button.
AXObject* control_object = CorrespondingControlForLabelElement();
HTMLLabelElement* label = LabelElementContainer();
if (control_object && control_object->IsCheckboxOrRadio() &&
control_object->NameFromLabelElement() &&
AccessibleNode::GetPropertyOrARIAAttribute(
label, AOMStringProperty::kRole) == g_null_atom) {
if (ignored_reasons) {
if (label && label != GetNode()) {
AXObject* label_ax_object = AXObjectCache().GetOrCreate(label);
ignored_reasons->push_back(
IgnoredReason(kAXLabelContainer, label_ax_object));
}
ignored_reasons->push_back(IgnoredReason(kAXLabelFor, control_object));
}
return true;
}
if (layout_object_->IsBR())
return false;
if (CanSetFocusAttribute() && GetNode() && !IsHTMLBodyElement(GetNode()))
return false;
if (IsLink())
return false;
if (IsInPageLinkTarget())
return false;
// A click handler might be placed on an otherwise ignored non-empty block
// element, e.g. a div. We shouldn't ignore such elements because if an AT
// sees the |ax::mojom::DefaultActionVerb::kClickAncestor|, it will look for
// the clickable ancestor and it expects to find one.
if (IsClickable())
return false;
if (layout_object_->IsText()) {
if (CanIgnoreTextAsEmpty()) {
if (ignored_reasons)
ignored_reasons->push_back(IgnoredReason(kAXEmptyText));
return true;
}
return false;
}
if (IsHeading())
return false;
if (IsLandmarkRelated())
return false;
// Header and footer tags may also be exposed as landmark roles but not
// always.
if (GetNode() &&
(GetNode()->HasTagName(kHeaderTag) || GetNode()->HasTagName(kFooterTag)))
return false;
// all controls are accessible
if (IsControl())
return false;
if (AriaRoleAttribute() != ax::mojom::Role::kUnknown)
return false;
// don't ignore labels, because they serve as TitleUIElements
Node* node = layout_object_->GetNode();
if (IsHTMLLabelElement(node))
return false;
// Anything that is content editable should not be ignored.
// However, one cannot just call node->hasEditableStyle() since that will ask
// if its parents are also editable. Only the top level content editable
// region should be exposed.
if (HasContentEditableAttributeSet())
return false;
if (RoleValue() == ax::mojom::Role::kAbbr)
return false;
// List items play an important role in defining the structure of lists. They
// should not be ignored.
if (RoleValue() == ax::mojom::Role::kListItem)
return false;
if (RoleValue() == ax::mojom::Role::kBlockquote)
return false;
if (RoleValue() == ax::mojom::Role::kDialog)
return false;
if (RoleValue() == ax::mojom::Role::kFigcaption)
return false;
if (RoleValue() == ax::mojom::Role::kFigure)
return false;
if (RoleValue() == ax::mojom::Role::kContentDeletion)
return false;
if (RoleValue() == ax::mojom::Role::kContentInsertion)
return false;
if (RoleValue() == ax::mojom::Role::kDetails)
return false;
if (RoleValue() == ax::mojom::Role::kMark)
return false;
if (RoleValue() == ax::mojom::Role::kMath)
return false;
if (RoleValue() == ax::mojom::Role::kMeter)
return false;
if (RoleValue() == ax::mojom::Role::kRuby)
return false;
if (RoleValue() == ax::mojom::Role::kSplitter)
return false;
if (RoleValue() == ax::mojom::Role::kTime)
return false;
if (RoleValue() == ax::mojom::Role::kProgressIndicator)
return false;
// if this element has aria attributes on it, it should not be ignored.
if (HasGlobalARIAAttribute())
return false;
if (IsImage())
return false;
if (IsCanvas()) {
if (CanvasHasFallbackContent())
return false;
const auto* canvas = ToLayoutHTMLCanvasOrNull(layout_object_);
if (canvas &&
(canvas->Size().Height() <= 1 || canvas->Size().Width() <= 1)) {
if (ignored_reasons)
ignored_reasons->push_back(IgnoredReason(kAXProbablyPresentational));
return true;
}
// Otherwise fall through; use presence of help text, title, or description
// to decide.
}
if (IsWebArea() || layout_object_->IsListMarkerIncludingNG())
return false;
// Using the title or accessibility description (so we
// check if there's some kind of accessible name for the element)
// to decide an element's visibility is not as definitive as
// previous checks, so this should remain as one of the last.
//
// These checks are simplified in the interest of execution speed;
// for example, any element having an alt attribute will make it
// not ignored, rather than just images.
if (HasAriaAttribute(GetElement()) || !GetAttribute(kAltAttr).IsEmpty() ||
!GetAttribute(kTitleAttr).IsEmpty())
return false;
// <span> tags are inline tags and not meant to convey information if they
// have no other ARIA information on them. If we don't ignore them, they may
// emit signals expected to come from their parent.
if (IsHTMLSpanElement(node)) {
if (ignored_reasons)
ignored_reasons->push_back(IgnoredReason(kAXUninteresting));
return true;
}
// Positioned elements and scrollable containers are important for
// determining bounding boxes.
if (IsScrollableContainer())
return false;
if (layout_object_->IsPositioned())
return false;
// Inner editor element of editable area with empty text provides bounds
// used to compute the character extent for index 0. This is the same as
// what the caret's bounds would be if the editable area is focused.
if (ParentObject() && ParentObject()->GetLayoutObject() &&
ParentObject()->GetLayoutObject()->IsTextControl()) {
return false;
}
// Ignore layout objects that are block flows with inline children. These
// are usually dummy layout objects that pad out the tree, but there are
// some exceptions below.
if (layout_object_->IsLayoutBlockFlow() && layout_object_->ChildrenInline() &&
!CanSetFocusAttribute()) {
// If the layout object has any plain text in it, that text will be
// inside a LineBox, so the layout object will have a first LineBox.
bool has_any_text = HasLineBox(ToLayoutBlockFlow(*layout_object_));
// Always include interesting-looking objects.
if (has_any_text || MouseButtonListener())
return false;
if (ignored_reasons)
ignored_reasons->push_back(IgnoredReason(kAXUninteresting));
return true;
}
// By default, objects should be ignored so that the AX hierarchy is not
// filled with unnecessary items.
if (ignored_reasons)
ignored_reasons->push_back(IgnoredReason(kAXUninteresting));
return true;
}
bool AXLayoutObject::HasAriaCellRole(Element* elem) const {
DCHECK(elem);
const AtomicString& aria_role_str = elem->FastGetAttribute(kRoleAttr);
if (aria_role_str.IsEmpty())
return false;
ax::mojom::Role aria_role = AriaRoleToWebCoreRole(aria_role_str);
return aria_role == ax::mojom::Role::kCell ||
aria_role == ax::mojom::Role::kColumnHeader ||
aria_role == ax::mojom::Role::kRowHeader;
}
// Return true if whitespace is not necessary to keep adjacent_node separate
// in screen reader output from surrounding nodes.
bool AXLayoutObject::CanIgnoreSpaceNextTo(LayoutObject* layout,
bool is_after) const {
if (!layout)
return true;
// If adjacent to a whitespace character, the current space can be ignored.
if (layout->IsText()) {
LayoutText* layout_text = ToLayoutText(layout);
if (layout_text->HasEmptyText())
return false;
if (layout_text->GetText().Impl()->ContainsOnlyWhitespaceOrEmpty())
return true;
auto adjacent_char =
is_after ? layout_text->FirstCharacterAfterWhitespaceCollapsing()
: layout_text->LastCharacterAfterWhitespaceCollapsing();
return adjacent_char == ' ' || adjacent_char == '\n' ||
adjacent_char == '\t';
}
// Keep spaces between images and other visible content.
if (layout->IsLayoutImage())
return false;
// Do not keep spaces between blocks.
if (!layout->IsLayoutInline())
return true;
// If next to an element that a screen reader will always read separately,
// the the space can be ignored.
// Elements that are naturally focusable even without a tabindex tend
// to be rendered separately even if there is no space between them.
// Some ARIA roles act like table cells and don't need adjacent whitespace to
// indicate separation.
// False negatives are acceptable in that they merely lead to extra whitespace
// static text nodes.
// TODO(aleventhal) Do we want this? Is it too hard/complex for Braille/Cvox?
Node* node = layout->GetNode();
if (node && node->IsElementNode()) {
Element* elem = ToElement(node);
if (HasAriaCellRole(elem))
return true;
}
// Test against the appropriate child text node.
LayoutInline* layout_inline = ToLayoutInline(layout);
LayoutObject* child =
is_after ? layout_inline->FirstChild() : layout_inline->LastChild();
return CanIgnoreSpaceNextTo(child, is_after);
}
bool AXLayoutObject::CanIgnoreTextAsEmpty() const {
DCHECK(layout_object_->IsText());
DCHECK(layout_object_->Parent());
LayoutText* layout_text = ToLayoutText(layout_object_);
// Ignore empty text
if (layout_text->HasEmptyText()) {
return true;
}
// Don't ignore node-less text (e.g. list bullets)
Node* node = GetNode();
if (!node)
return false;
// Always keep if anything other than collapsible whitespace.
if (!layout_text->IsAllCollapsibleWhitespace())
return false;
// Will now look at sibling nodes.
// Using "skipping children" methods as we need the closest element to the
// whitespace markup-wise, e.g. tag1 in these examples:
// [whitespace] <tag1><tag2>x</tag2></tag1>
// <span>[whitespace]</span> <tag1><tag2>x</tag2></tag1>
Node* prev_node = FlatTreeTraversal::PreviousSkippingChildren(*node);
if (!prev_node)
return true;
Node* next_node = FlatTreeTraversal::NextSkippingChildren(*node);
if (!next_node)
return true;
// Ignore extra whitespace-only text if a sibling will be presented
// separately by screen readers whether whitespace is there or not.
if (CanIgnoreSpaceNextTo(prev_node->GetLayoutObject(), false) ||
CanIgnoreSpaceNextTo(next_node->GetLayoutObject(), true))
return true;
// Text elements with empty whitespace are returned, because of cases
// such as <span>Hello</span><span> </span><span>World</span>. Keeping
// the whitespace-only node means we now correctly expose "Hello World".
// See crbug.com/435765.
return false;
}
//
// Properties of static elements.
//
const AtomicString& AXLayoutObject::AccessKey() const {
Node* node = layout_object_->GetNode();
if (!node)
return g_null_atom;
if (!node->IsElementNode())
return g_null_atom;
return ToElement(node)->getAttribute(kAccesskeyAttr);
}
RGBA32 AXLayoutObject::ComputeBackgroundColor() const {
if (!GetLayoutObject())
return AXNodeObject::BackgroundColor();
Color blended_color = Color::kTransparent;
// Color::blend should be called like this: background.blend(foreground).
for (LayoutObject* layout_object = GetLayoutObject(); layout_object;
layout_object = layout_object->Parent()) {
const AXObject* ax_parent = AXObjectCache().GetOrCreate(layout_object);
if (ax_parent && ax_parent != this) {
Color parent_color = ax_parent->BackgroundColor();
blended_color = parent_color.Blend(blended_color);
return blended_color.Rgb();
}
const ComputedStyle* style = layout_object->Style();
if (!style || !style->HasBackground())
continue;
Color current_color =
style->VisitedDependentColor(GetCSSPropertyBackgroundColor());
blended_color = current_color.Blend(blended_color);
// Continue blending until we get no transparency.
if (!blended_color.HasAlpha())
break;
}
// If we still have some transparency, blend in the document base color.
if (blended_color.HasAlpha()) {
LocalFrameView* view = DocumentFrameView();
if (view) {
Color document_base_color = view->BaseBackgroundColor();
blended_color = document_base_color.Blend(blended_color);
} else {
// Default to a white background.
blended_color.BlendWithWhite();
}
}
return blended_color.Rgb();
}
RGBA32 AXLayoutObject::GetColor() const {
if (!GetLayoutObject() || IsColorWell())
return AXNodeObject::GetColor();
const ComputedStyle* style = GetLayoutObject()->Style();
if (!style)
return AXNodeObject::GetColor();
Color color = style->VisitedDependentColor(GetCSSPropertyColor());
return color.Rgb();
}
AtomicString AXLayoutObject::FontFamily() const {
if (!GetLayoutObject())
return AXNodeObject::FontFamily();
const ComputedStyle* style = GetLayoutObject()->Style();
if (!style)
return AXNodeObject::FontFamily();
FontDescription& font_description =
const_cast<FontDescription&>(style->GetFontDescription());
return font_description.FirstFamily().Family();
}
// Font size is in pixels.
float AXLayoutObject::FontSize() const {
if (!GetLayoutObject())
return AXNodeObject::FontSize();
const ComputedStyle* style = GetLayoutObject()->Style();
if (!style)
return AXNodeObject::FontSize();
return style->ComputedFontSize();
}
String AXLayoutObject::ImageDataUrl(const IntSize& max_size) const {
Node* node = GetNode();
if (!node)
return String();
ImageBitmapOptions* options = ImageBitmapOptions::Create();
ImageBitmap* image_bitmap = nullptr;
Document* document = &node->GetDocument();
if (auto* image = ToHTMLImageElementOrNull(node)) {
image_bitmap = ImageBitmap::Create(image, base::Optional<IntRect>(),
document, options);
} else if (auto* canvas = ToHTMLCanvasElementOrNull(node)) {
image_bitmap =
ImageBitmap::Create(canvas, base::Optional<IntRect>(), options);
} else if (auto* video = ToHTMLVideoElementOrNull(node)) {
image_bitmap = ImageBitmap::Create(video, base::Optional<IntRect>(),
document, options);
}
if (!image_bitmap)
return String();
scoped_refptr<StaticBitmapImage> bitmap_image = image_bitmap->BitmapImage();
if (!bitmap_image)
return String();
sk_sp<SkImage> image = bitmap_image->PaintImageForCurrentFrame().GetSkImage();
if (!image || image->width() <= 0 || image->height() <= 0)
return String();
// Determine the width and height of the output image, using a proportional
// scale factor such that it's no larger than |maxSize|, if |maxSize| is not
// empty. It only resizes the image to be smaller (if necessary), not
// larger.
float x_scale =
max_size.Width() ? max_size.Width() * 1.0 / image->width() : 1.0;
float y_scale =
max_size.Height() ? max_size.Height() * 1.0 / image->height() : 1.0;
float scale = std::min(x_scale, y_scale);
if (scale >= 1.0)
scale = 1.0;
int width = std::round(image->width() * scale);
int height = std::round(image->height() * scale);
// Draw the scaled image into a bitmap in native format.
SkBitmap bitmap;
bitmap.allocPixels(SkImageInfo::MakeN32(width, height, kPremul_SkAlphaType));
SkCanvas canvas(bitmap);
canvas.clear(SK_ColorTRANSPARENT);
canvas.drawImageRect(image, SkRect::MakeIWH(width, height), nullptr);
// Copy the bits into a buffer in RGBA_8888 unpremultiplied format
// for encoding.
SkImageInfo info = SkImageInfo::Make(width, height, kRGBA_8888_SkColorType,
kUnpremul_SkAlphaType);
size_t row_bytes = info.minRowBytes();
Vector<char> pixel_storage(
SafeCast<wtf_size_t>(info.computeByteSize(row_bytes)));
SkPixmap pixmap(info, pixel_storage.data(), row_bytes);
if (!SkImage::MakeFromBitmap(bitmap)->readPixels(pixmap, 0, 0))
return String();
// Encode as a PNG and return as a data url.
std::unique_ptr<ImageDataBuffer> buffer = ImageDataBuffer::Create(pixmap);
if (!buffer)
return String();
return buffer->ToDataURL(kMimeTypePng, 1.0);
}
String AXLayoutObject::GetText() const {
if (IsPasswordFieldAndShouldHideValue()) {
if (!GetLayoutObject())
return String();
const ComputedStyle* style = GetLayoutObject()->Style();
if (!style)
return String();
unsigned unmasked_text_length = AXNodeObject::GetText().length();
if (!unmasked_text_length)
return String();
UChar mask_character = 0;
switch (style->TextSecurity()) {
case ETextSecurity::kNone:
break; // Fall through to the non-password branch.
case ETextSecurity::kDisc:
mask_character = kBulletCharacter;
break;
case ETextSecurity::kCircle:
mask_character = kWhiteBulletCharacter;
break;
case ETextSecurity::kSquare:
mask_character = kBlackSquareCharacter;
break;
}
if (mask_character) {
StringBuilder masked_text;
masked_text.ReserveCapacity(unmasked_text_length);
for (unsigned i = 0; i < unmasked_text_length; ++i)
masked_text.Append(mask_character);
return masked_text.ToString();
}
}
return AXNodeObject::GetText();
}
ax::mojom::TextDirection AXLayoutObject::GetTextDirection() const {
if (!GetLayoutObject())
return AXNodeObject::GetTextDirection();
const ComputedStyle* style = GetLayoutObject()->Style();
if (!style)
return AXNodeObject::GetTextDirection();
if (style->IsHorizontalWritingMode()) {
switch (style->Direction()) {
case TextDirection::kLtr:
return ax::mojom::TextDirection::kLtr;
case TextDirection::kRtl:
return ax::mojom::TextDirection::kRtl;
}
} else {
switch (style->Direction()) {
case TextDirection::kLtr:
return ax::mojom::TextDirection::kTtb;
case TextDirection::kRtl:
return ax::mojom::TextDirection::kBtt;
}
}
return AXNodeObject::GetTextDirection();
}
ax::mojom::TextPosition AXLayoutObject::GetTextPosition() const {
if (!GetLayoutObject())
return AXNodeObject::GetTextPosition();
const ComputedStyle* style = GetLayoutObject()->Style();
if (!style)
return AXNodeObject::GetTextPosition();
switch (style->VerticalAlign()) {
case EVerticalAlign::kBaseline:
case EVerticalAlign::kMiddle:
case EVerticalAlign::kTextTop:
case EVerticalAlign::kTextBottom:
case EVerticalAlign::kTop:
case EVerticalAlign::kBottom:
case EVerticalAlign::kBaselineMiddle:
case EVerticalAlign::kLength:
return AXNodeObject::GetTextPosition();
case EVerticalAlign::kSub:
return ax::mojom::TextPosition::kSubscript;
case EVerticalAlign::kSuper:
return ax::mojom::TextPosition::kSuperscript;
}
}
int AXLayoutObject::TextLength() const {
if (!IsTextControl())
return -1;
return GetText().length();
}
static unsigned TextStyleFlag(ax::mojom::TextStyle text_style_enum) {
return static_cast<unsigned>(1 << static_cast<int>(text_style_enum));
}
int32_t AXLayoutObject::GetTextStyle() const {
if (!GetLayoutObject())
return AXNodeObject::GetTextStyle();
const ComputedStyle* style = GetLayoutObject()->Style();
if (!style)
return AXNodeObject::GetTextStyle();
int32_t text_style = 0;
if (style->GetFontWeight() == BoldWeightValue())
text_style |= TextStyleFlag(ax::mojom::TextStyle::kBold);
if (style->GetFontDescription().Style() == ItalicSlopeValue())
text_style |= TextStyleFlag(ax::mojom::TextStyle::kItalic);
if (style->GetTextDecoration() == TextDecoration::kUnderline)
text_style |= TextStyleFlag(ax::mojom::TextStyle::kUnderline);
if (style->GetTextDecoration() == TextDecoration::kLineThrough)
text_style |= TextStyleFlag(ax::mojom::TextStyle::kLineThrough);
return text_style;
}
//
// Inline text boxes.
//
void AXLayoutObject::LoadInlineTextBoxes() {
if (!GetLayoutObject())
return;
if (GetLayoutObject()->IsText()) {
ClearChildren();
AddInlineTextBoxChildren(true);
return;
}
for (const auto& child : children_) {
child->LoadInlineTextBoxes();
}
}
static bool ShouldUseLayoutNG(const LayoutObject& layout_object) {
return (layout_object.IsLayoutInline() || layout_object.IsText()) &&
layout_object.ContainingNGBlockFlow();
}
// Note: |NextOnLineInternalNG()| returns null when fragment for |layout_object|
// is culled as legacy layout version since |LayoutInline::LastLineBox()|
// returns null when it is culled.
// See also |PreviousOnLineInternalNG()| which is identical except for using
// "next" and |back()| instead of "previous" and |front()|.
static AXObject* NextOnLineInternalNG(const AXObject& ax_object) {
DCHECK(ax_object.GetLayoutObject());
const LayoutObject& layout_object = *ax_object.GetLayoutObject();
DCHECK(!layout_object.IsListMarkerIncludingNG()) << layout_object;
DCHECK(ShouldUseLayoutNG(layout_object)) << layout_object;
const auto fragments = NGPaintFragment::InlineFragmentsFor(&layout_object);
if (fragments.IsEmpty() || fragments.IsInLayoutNGInlineFormattingContext())
return nullptr;
for (NGPaintFragmentTraversalContext runner =
NGPaintFragmentTraversal::NextInlineLeafOf(
NGPaintFragmentTraversalContext::Create(&fragments.back()));
!runner.IsNull();
runner = NGPaintFragmentTraversal::NextInlineLeafOf(runner)) {
LayoutObject* runner_layout_object =
runner.GetFragment()->GetLayoutObject();
if (AXObject* result =
ax_object.AXObjectCache().GetOrCreate(runner_layout_object))
return result;
}
if (!ax_object.ParentObject())
return nullptr;
// Returns next object of parent, since next of |ax_object| isn't appeared on
// line.
return ax_object.ParentObject()->NextOnLine();
}
AXObject* AXLayoutObject::NextOnLine() const {
if (!GetLayoutObject())
return nullptr;
AXObject* result = nullptr;
if (GetLayoutObject()->IsListMarkerIncludingNG()) {
AXObject* next_sibling = RawNextSibling();
if (!next_sibling || !next_sibling->Children().size())
return nullptr;
result = next_sibling->Children()[0].Get();
} else if (ShouldUseLayoutNG(*GetLayoutObject())) {
result = NextOnLineInternalNG(*this);
} else {
InlineBox* inline_box = nullptr;
if (GetLayoutObject()->IsLayoutInline()) {
inline_box = ToLayoutInline(GetLayoutObject())->LastLineBox();
} else if (GetLayoutObject()->IsText()) {
inline_box = ToLayoutText(GetLayoutObject())->LastTextBox();
}
if (!inline_box)
return nullptr;
for (InlineBox* next = inline_box->NextOnLine(); next;
next = next->NextOnLine()) {
LayoutObject* layout_object =
LineLayoutAPIShim::LayoutObjectFrom(next->GetLineLayoutItem());
result = AXObjectCache().GetOrCreate(layout_object);
if (result)
break;
}
if (!result && ParentObject())
result = ParentObject()->NextOnLine();
}
// For consistency between the forward and backward directions, try to always
// return leaf nodes.
while (result && result->Children().size())
result = result->Children()[0].Get();
return result;
}
// Note: |PreviousOnLineInlineNG()| returns null when fragment for
// |layout_object| is culled as legacy layout version since
// |LayoutInline::FirstLineBox()| returns null when it is culled. See also
// |NextOnLineNG()| which is identical except for using "previous" and |front()|
// instead of "next" and |back()|.
static AXObject* PreviousOnLineInlineNG(const AXObject& ax_object) {
DCHECK(ax_object.GetLayoutObject());
const LayoutObject& layout_object = *ax_object.GetLayoutObject();
DCHECK(!layout_object.IsListMarkerIncludingNG()) << layout_object;
DCHECK(ShouldUseLayoutNG(layout_object)) << layout_object;
const auto fragments = NGPaintFragment::InlineFragmentsFor(&layout_object);
if (fragments.IsEmpty() || fragments.IsInLayoutNGInlineFormattingContext())
return nullptr;
for (NGPaintFragmentTraversalContext runner =
NGPaintFragmentTraversal::PreviousInlineLeafOf(
NGPaintFragmentTraversalContext::Create(&fragments.front()));
!runner.IsNull();
runner = NGPaintFragmentTraversal::PreviousInlineLeafOf(runner)) {
LayoutObject* earlier_layout_object =
runner.GetFragment()->GetLayoutObject();
if (AXObject* result =
ax_object.AXObjectCache().GetOrCreate(earlier_layout_object))
return result;
}
if (!ax_object.ParentObject())
return nullptr;
// Returns previous object of parent, since next of |ax_object| isn't appeared
// on line.
return ax_object.ParentObject()->PreviousOnLine();
}
AXObject* AXLayoutObject::PreviousOnLine() const {
if (!GetLayoutObject())
return nullptr;
AXObject* result = nullptr;
if (ShouldUseLayoutNG(*GetLayoutObject())) {
result = PreviousOnLineInlineNG(*this);
} else {
InlineBox* inline_box = nullptr;
if (GetLayoutObject()->IsLayoutInline()) {
inline_box = ToLayoutInline(GetLayoutObject())->FirstLineBox();
} else if (GetLayoutObject()->IsText()) {
inline_box = ToLayoutText(GetLayoutObject())->FirstTextBox();
}
if (!inline_box)
return nullptr;
for (InlineBox* prev = inline_box->PrevOnLine(); prev;
prev = prev->PrevOnLine()) {
LayoutObject* layout_object =
LineLayoutAPIShim::LayoutObjectFrom(prev->GetLineLayoutItem());
result = AXObjectCache().GetOrCreate(layout_object);
if (result)
break;
}
if (!result && ParentObject())
result = ParentObject()->PreviousOnLine();
}
// For consistency between the forward and backward directions, try to always
// return leaf nodes.
while (result && result->Children().size())
result = result->Children()[result->Children().size() - 1].Get();
return result;
}
//
// Properties of interactive elements.
//
String AXLayoutObject::StringValue() const {
if (!layout_object_)
return String();
LayoutBoxModelObject* css_box = GetLayoutBoxModelObject();
if (css_box && css_box->IsMenuList()) {
// LayoutMenuList will go straight to the text() of its selected item.
// This has to be overridden in the case where the selected item has an ARIA
// label.
HTMLSelectElement* select_element =
ToHTMLSelectElement(layout_object_->GetNode());
int selected_index = select_element->selectedIndex();
const HeapVector<Member<HTMLElement>>& list_items =
select_element->GetListItems();
if (selected_index >= 0 &&
static_cast<size_t>(selected_index) < list_items.size()) {
const AtomicString& overridden_description =
list_items[selected_index]->FastGetAttribute(kAriaLabelAttr);
if (!overridden_description.IsNull())
return overridden_description;
}
return ToLayoutMenuList(layout_object_)->GetText();
}
if (IsWebArea()) {
// FIXME: Why would a layoutObject exist when the Document isn't attached to
// a frame?
if (layout_object_->GetFrame())
return String();
NOTREACHED();
}
if (IsTextControl())
return GetText();
if (layout_object_->IsFileUploadControl())
return ToLayoutFileUploadControl(layout_object_)->FileTextValue();
// Handle other HTML input elements that aren't text controls, like date and
// time controls, by returning their value converted to text, with the
// exception of checkboxes and radio buttons (which would return "on"), and
// buttons which will return their name.
// https://html.spec.whatwg.org/C/#dom-input-value
if (const auto* input = ToHTMLInputElementOrNull(GetNode())) {
if (input->type() != input_type_names::kButton &&
input->type() != input_type_names::kCheckbox &&
input->type() != input_type_names::kImage &&
input->type() != input_type_names::kRadio &&
input->type() != input_type_names::kReset &&
input->type() != input_type_names::kSubmit) {
return input->value();
}
}
// FIXME: We might need to implement a value here for more types
// FIXME: It would be better not to advertise a value at all for the types for
// which we don't implement one; this would require subclassing or making
// accessibilityAttributeNames do something other than return a single static
// array.
return String();
}
String AXLayoutObject::TextAlternative(bool recursive,
bool in_aria_labelled_by_traversal,
AXObjectSet& visited,
ax::mojom::NameFrom& name_from,
AXRelatedObjectVector* related_objects,
NameSources* name_sources) const {
if (layout_object_) {
String text_alternative;
bool found_text_alternative = false;
if (layout_object_->IsBR()) {
text_alternative = String("\n");
found_text_alternative = true;
} else if (layout_object_->IsText() &&
(!recursive || !layout_object_->IsCounter())) {
LayoutText* layout_text = ToLayoutText(layout_object_);
String visible_text = layout_text->PlainText(); // Actual rendered text.
// If no text boxes we assume this is unrendered end-of-line whitespace.
// TODO find robust way to deterministically detect end-of-line space.
if (visible_text.IsEmpty()) {
// No visible rendered text -- must be whitespace.
// Either it is useful whitespace for separating words or not.
if (layout_text->IsAllCollapsibleWhitespace()) {
if (cached_is_ignored_)
return "";
// If no textboxes, this was whitespace at the line's end.
text_alternative = " ";
} else {
text_alternative = layout_text->GetText();
}
} else {
text_alternative = visible_text;
}
found_text_alternative = true;
} else if (layout_object_->IsListMarker() && !recursive) {
text_alternative = ToLayoutListMarker(layout_object_)->TextAlternative();
found_text_alternative = true;
} else if (layout_object_->IsLayoutNGListMarker() && !recursive) {
text_alternative =
ToLayoutNGListMarker(layout_object_)->TextAlternative();
found_text_alternative = true;
}
if (found_text_alternative) {
name_from = ax::mojom::NameFrom::kContents;
if (name_sources) {
name_sources->push_back(NameSource(false));
name_sources->back().type = name_from;
name_sources->back().text = text_alternative;
}
return text_alternative;
}
}
return AXNodeObject::TextAlternative(recursive, in_aria_labelled_by_traversal,
visited, name_from, related_objects,
name_sources);
}
//
// ARIA attributes.
//
void AXLayoutObject::AriaOwnsElements(AXObjectVector& owns) const {
AccessibilityChildrenFromAOMProperty(AOMRelationListProperty::kOwns, owns);
}
void AXLayoutObject::AriaDescribedbyElements(
AXObjectVector& describedby) const {
AccessibilityChildrenFromAOMProperty(AOMRelationListProperty::kDescribedBy,
describedby);
}
ax::mojom::HasPopup AXLayoutObject::HasPopup() const {
const AtomicString& has_popup =
GetAOMPropertyOrARIAAttribute(AOMStringProperty::kHasPopUp);
if (!has_popup.IsNull()) {
if (EqualIgnoringASCIICase(has_popup, "false"))
return ax::mojom::HasPopup::kFalse;
if (EqualIgnoringASCIICase(has_popup, "listbox"))
return ax::mojom::HasPopup::kListbox;
if (EqualIgnoringASCIICase(has_popup, "tree"))
return ax::mojom::HasPopup::kTree;
if (EqualIgnoringASCIICase(has_popup, "grid"))
return ax::mojom::HasPopup::kGrid;
if (EqualIgnoringASCIICase(has_popup, "dialog"))
return ax::mojom::HasPopup::kDialog;
// To provide backward compatibility with ARIA 1.0 content,
// user agents MUST treat an aria-haspopup value of true
// as equivalent to a value of menu.
// And unknown value also return menu too.
if (EqualIgnoringASCIICase(has_popup, "true") ||
EqualIgnoringASCIICase(has_popup, "menu") || !has_popup.IsEmpty())
return ax::mojom::HasPopup::kMenu;
}
// ARIA 1.1 default value of haspopup for combobox is "listbox".
if (RoleValue() == ax::mojom::Role::kComboBoxMenuButton ||
RoleValue() == ax::mojom::Role::kTextFieldWithComboBox)
return ax::mojom::HasPopup::kListbox;
return AXObject::HasPopup();
}
// TODO : Aria-dropeffect and aria-grabbed are deprecated in aria 1.1
// Also those properties are expected to be replaced by a new feature in
// a future version of WAI-ARIA. After that we will re-implement them
// following new spec.
bool AXLayoutObject::SupportsARIADragging() const {
const AtomicString& grabbed = GetAttribute(kAriaGrabbedAttr);
return EqualIgnoringASCIICase(grabbed, "true") ||
EqualIgnoringASCIICase(grabbed, "false");
}
bool AXLayoutObject::SupportsARIADropping() const {
const AtomicString& drop_effect = GetAttribute(kAriaDropeffectAttr);
return !drop_effect.IsEmpty();
}
bool AXLayoutObject::SupportsARIAFlowTo() const {
return !GetAttribute(kAriaFlowtoAttr).IsEmpty();
}
bool AXLayoutObject::SupportsARIAOwns() const {
if (!layout_object_)
return false;
const AtomicString& aria_owns = GetAttribute(kAriaOwnsAttr);
return !aria_owns.IsEmpty();
}
//
// ARIA live-region features.
//
const AtomicString& AXLayoutObject::LiveRegionStatus() const {
DEFINE_STATIC_LOCAL(const AtomicString, live_region_status_assertive,
("assertive"));
DEFINE_STATIC_LOCAL(const AtomicString, live_region_status_polite,
("polite"));
DEFINE_STATIC_LOCAL(const AtomicString, live_region_status_off, ("off"));
const AtomicString& live_region_status =
GetAOMPropertyOrARIAAttribute(AOMStringProperty::kLive);
// These roles have implicit live region status.
if (live_region_status.IsEmpty()) {
switch (RoleValue()) {
case ax::mojom::Role::kAlert:
return live_region_status_assertive;
case ax::mojom::Role::kLog:
case ax::mojom::Role::kStatus:
return live_region_status_polite;
case ax::mojom::Role::kTimer:
case ax::mojom::Role::kMarquee:
return live_region_status_off;
default:
break;
}
}
return live_region_status;
}
const AtomicString& AXLayoutObject::LiveRegionRelevant() const {
DEFINE_STATIC_LOCAL(const AtomicString, default_live_region_relevant,
("additions text"));
const AtomicString& relevant =
GetAOMPropertyOrARIAAttribute(AOMStringProperty::kRelevant);
// Default aria-relevant = "additions text".
if (relevant.IsEmpty())
return default_live_region_relevant;
return relevant;
}
//
// Hit testing.
//
AXObject* AXLayoutObject::AccessibilityHitTest(const IntPoint& point) const {
if (!layout_object_ || !layout_object_->HasLayer() ||
!layout_object_->IsBox())
return nullptr;
auto* frame_view = DocumentFrameView();
if (!frame_view || !frame_view->UpdateAllLifecyclePhasesExceptPaint())
return nullptr;
PaintLayer* layer = ToLayoutBox(layout_object_)->Layer();
HitTestRequest request(HitTestRequest::kReadOnly | HitTestRequest::kActive);
HitTestLocation location(point);
HitTestResult hit_test_result = HitTestResult(request, location);
layer->HitTest(location, hit_test_result,
LayoutRect(LayoutRect::InfiniteIntRect()));
Node* node = hit_test_result.InnerNode();
if (!node)
return nullptr;
if (auto* area = ToHTMLAreaElementOrNull(node))
return AccessibilityImageMapHitTest(area, point);
if (auto* option = ToHTMLOptionElementOrNull(node)) {
node = option->OwnerSelectElement();
if (!node)
return nullptr;
}
LayoutObject* obj = node->GetLayoutObject();
if (!obj)
return nullptr;
AXObject* result = AXObjectCache().GetOrCreate(obj);
result->UpdateChildrenIfNecessary();
// Allow the element to perform any hit-testing it might need to do to reach
// non-layout children.
result = result->ElementAccessibilityHitTest(point);
if (result && result->AccessibilityIsIgnored()) {
// If this element is the label of a control, a hit test should return the
// control.
if (result->IsAXLayoutObject()) {
AXObject* control_object =
ToAXLayoutObject(result)->CorrespondingControlForLabelElement();
if (control_object && control_object->NameFromLabelElement())
return control_object;
}
result = result->ParentObjectUnignored();
}
return result;
}
AXObject* AXLayoutObject::ElementAccessibilityHitTest(
const IntPoint& point) const {
if (IsSVGImage())
return RemoteSVGElementHitTest(point);
return AXObject::ElementAccessibilityHitTest(point);
}
//
// Low-level accessibility tree exploration, only for use within the
// accessibility module.
//
// LAYOUT TREE WALKING ALGORITHM
//
// The fundamental types of elements in the Blink layout tree are block
// elements and inline elements. It can get a little confusing when
// an inline element has both inline and block children, for example:
//
// <a href="#">
// Before Block
// <div>
// In Block
// </div>
// Outside Block
// </a>
//
// Blink wants to maintain the invariant that all of the children of a node
// are either all block or all inline, so it creates three anonymous blocks:
//
// #1 LayoutBlockFlow (anonymous)
// #2 LayoutInline A continuation=#4
// #3 LayoutText "Before Block"
// #4 LayoutBlockFlow (anonymous) continuation=#8
// #5 LayoutBlockFlow DIV
// #6 LayoutText "In Block"
// #7 LayoutBlockFlow (anonymous)
// #8 LayoutInline A is_continuation
// #9 LayoutText "Outside Block"
//
// For a good explanation of why this is done, see this blog entry. It's
// describing WebKit in 2007, but the fundamentals haven't changed much.
//
// https://webkit.org/blog/115/webcore-rendering-ii-blocks-and-inlines/
//
// Now, it's important to understand that we couldn't just use the layout
// tree as the accessibility tree as-is, because the div is no longer
// inside the link! In fact, the link has been split into two different
// nodes, #2 and #8. Luckily, the layout tree contains continuations to
// help us untangle situations like this.
//
// Here's the algorithm we use to walk the layout tree in order to build
// the accessibility tree:
//
// 1. When computing the first child or next sibling of a node, skip over any
// LayoutObjects that are continuations.
//
// 2. When computing the next sibling of a node and there are no more siblings
// in the layout tree, see if the parent node has a continuation, and if
// so follow it and make that the next sibling.
//
// 3. When computing the first child of a node that has a continuation but
// no children in the layout tree, the continuation is the first child.
//
// The end result is this tree, which we use as the basis for the
// accessibility tree.
//
// #1 LayoutBlockFlow (anonymous)
// #2 LayoutInline A
// #3 LayoutText "Before Block"
// #4 LayoutBlockFlow (anonymous)
// #5 LayoutBlockFlow DIV
// #6 LayoutText "In Block"
// #8 LayoutInline A is_continuation
// #9 LayoutText "Outside Block"
// #7 LayoutBlockFlow (anonymous)
//
// This algorithm results in an accessibility tree that preserves containment
// (i.e. the contents of the link in the example above are descendants of the
// link node) while including all of the rich layout detail from the layout
// tree.
//
// There are just a couple of other corner cases to walking the layout tree:
//
// * Walk tables in table order (thead, tbody, tfoot), which may not match
// layout order.
// * Skip CSS first-letter nodes.
//
// Given a layout object, return the start of the continuation chain.
static inline LayoutInline* StartOfContinuations(LayoutObject* layout_object) {
// See LAYOUT TREE WALKING ALGORITHM, above, for more context as to why
// we need to do this.
// For inline elements, if it's a continuation, the start of the chain
// is always the primary layout object associated with the node.
if (layout_object->IsInlineElementContinuation())
return ToLayoutInline(layout_object->GetNode()->GetLayoutObject());
// Blocks with a previous continuation always have a next continuation,
// so we can get the next continuation and do the same trick to get
// the primary layout object associated with the node.
if (layout_object->IsLayoutBlockFlow() &&
ToLayoutBlockFlow(layout_object)->InlineElementContinuation()) {
LayoutInline* result = ToLayoutInline(ToLayoutBlockFlow(layout_object)
->InlineElementContinuation()
->GetNode()
->GetLayoutObject());
DCHECK_NE(result, layout_object);
return result;
}
return nullptr;
}
// See LAYOUT TREE WALKING ALGORITHM, above, for details.
static inline LayoutObject* ParentLayoutObject(LayoutObject* layout_object) {
if (!layout_object)
return nullptr;
// If the node is a continuation, the parent is the start of the continuation
// chain. See LAYOUT TREE WALKING ALGORITHM, above, for more context as to
// why we need to do this.
LayoutObject* start_of_conts = StartOfContinuations(layout_object);
if (start_of_conts)
return start_of_conts;
// Otherwise just return the parent in the layout tree.
return layout_object->Parent();
}
// See LAYOUT TREE WALKING ALGORITHM, above, for details.
// Return true if this layout object is the continuation of some other
// layout object.
static bool IsContinuation(LayoutObject* layout_object) {
if (layout_object->IsElementContinuation())
return true;
if (layout_object->IsAnonymousBlock() && layout_object->IsLayoutBlockFlow() &&
ToLayoutBlockFlow(layout_object)->Continuation())
return true;
return false;
}
// See LAYOUT TREE WALKING ALGORITHM, above, for details.
// Return the continuation of this layout object, or nullptr if it doesn't
// have one.
LayoutObject* GetContinuation(LayoutObject* layout_object) {
if (layout_object->IsLayoutInline())
return ToLayoutInline(layout_object)->Continuation();
if (layout_object->IsLayoutBlockFlow())
return ToLayoutBlockFlow(layout_object)->Continuation();
return nullptr;
}
// See LAYOUT TREE WALKING ALGORITHM, above, for details.
AXObject* AXLayoutObject::RawFirstChild() const {
if (!layout_object_)
return nullptr;
// Walk sections of a table (thead, tbody, tfoot) in visual order.
// Note: always call RecalcSectionsIfNeeded() before accessing
// the sections of a LayoutTable.
if (layout_object_->IsTable()) {
LayoutTable* table = ToLayoutTable(layout_object_);
table->RecalcSectionsIfNeeded();
return AXObjectCache().GetOrCreate(table->TopSection());
}
if (layout_object_->IsLayoutNGListMarker()) {
// We don't care tree structure of list marker.
return nullptr;
}
LayoutObject* first_child = layout_object_->SlowFirstChild();
// CSS first-letter pseudo element is handled as continuation. Returning it
// will result in duplicated elements.
if (first_child && first_child->IsText() &&
ToLayoutText(first_child)->IsTextFragment() &&
ToLayoutTextFragment(first_child)->GetFirstLetterPseudoElement())
return nullptr;
// Skip over continuations.
while (first_child && IsContinuation(first_child))
first_child = first_child->NextSibling();
// If there's a first child that's not a continuation, return that.
if (first_child)
return AXObjectCache().GetOrCreate(first_child);
// Finally check if this object has no children but it has a continuation
// itself - and if so, it's the first child.
LayoutObject* continuation = GetContinuation(layout_object_);
if (continuation)
return AXObjectCache().GetOrCreate(continuation);
return nullptr;
}
// See LAYOUT TREE WALKING ALGORITHM, above, for details.
AXObject* AXLayoutObject::RawNextSibling() const {
if (!layout_object_)
return nullptr;
// Walk sections of a table (thead, tbody, tfoot) in visual order.
if (layout_object_->IsTableSection()) {
LayoutTableSection* section = ToLayoutTableSection(layout_object_);
return AXObjectCache().GetOrCreate(
section->Table()->SectionBelow(section, kSkipEmptySections));
}
// If it's not a continuation, just get the next sibling from the
// layout tree, skipping over continuations.
if (!IsContinuation(layout_object_)) {
LayoutObject* next_sibling = layout_object_->NextSibling();
while (next_sibling && IsContinuation(next_sibling))
next_sibling = next_sibling->NextSibling();
if (next_sibling)
return AXObjectCache().GetOrCreate(next_sibling);
}
// If we've run out of siblings, check to see if the parent of this
// object has a continuation, and if so, follow it.
LayoutObject* parent = layout_object_->Parent();
if (parent) {
LayoutObject* continuation = GetContinuation(parent);
if (continuation)
return AXObjectCache().GetOrCreate(continuation);
}
return nullptr;
}
//
// High-level accessibility tree access.
//
AXObject* AXLayoutObject::ComputeParent() const {
DCHECK(!IsDetached());
if (!layout_object_)
return nullptr;
if (AriaRoleAttribute() == ax::mojom::Role::kMenuBar)
return AXObjectCache().GetOrCreate(layout_object_->Parent());
// menuButton and its corresponding menu are DOM siblings, but Accessibility
// needs them to be parent/child.
if (AriaRoleAttribute() == ax::mojom::Role::kMenu) {
AXObject* parent = MenuButtonForMenu();
if (parent)
return parent;
}
LayoutObject* parent_layout_obj = ParentLayoutObject(layout_object_);
if (parent_layout_obj)
return AXObjectCache().GetOrCreate(parent_layout_obj);
// A WebArea's parent should be the page popup owner, if any, otherwise null.
if (IsWebArea()) {
LocalFrame* frame = layout_object_->GetFrame();
return AXObjectCache().GetOrCreate(frame->PagePopupOwner());
}
return nullptr;
}
AXObject* AXLayoutObject::ComputeParentIfExists() const {
if (!layout_object_)
return nullptr;
if (AriaRoleAttribute() == ax::mojom::Role::kMenuBar)
return AXObjectCache().Get(layout_object_->Parent());
// menuButton and its corresponding menu are DOM siblings, but Accessibility
// needs them to be parent/child.
if (AriaRoleAttribute() == ax::mojom::Role::kMenu) {
AXObject* parent = MenuButtonForMenuIfExists();
if (parent)
return parent;
}
LayoutObject* parent_layout_obj = ParentLayoutObject(layout_object_);
if (parent_layout_obj)
return AXObjectCache().Get(parent_layout_obj);
// A WebArea's parent should be the page popup owner, if any, otherwise null.
if (IsWebArea()) {
LocalFrame* frame = layout_object_->GetFrame();
return AXObjectCache().Get(frame->PagePopupOwner());
}
return nullptr;
}
void AXLayoutObject::AddChildren() {
if (IsDetached())
return;
if (IsHTMLCanvasElement(GetNode()))
return AXNodeObject::AddChildren();
// If the need to add more children in addition to existing children arises,
// childrenChanged should have been called, leaving the object with no
// children.
DCHECK(!have_children_);
have_children_ = true;
AXObjectVector owned_children;
ComputeAriaOwnsChildren(owned_children);
for (AXObject* obj = RawFirstChild(); obj; obj = obj->RawNextSibling()) {
if (!AXObjectCache().IsAriaOwned(obj)) {
obj->SetParent(this);
AddChild(obj);
}
}
AddHiddenChildren();
AddPopupChildren();
AddImageMapChildren();
AddRemoteSVGChildren();
AddTableChildren();
AddInlineTextBoxChildren(false);
AddValidationMessageChild();
AddAccessibleNodeChildren();
for (const auto& child : children_) {
if (!child->CachedParentObject())
child->SetParent(this);
}
for (const auto& owned_child : owned_children)
AddChild(owned_child);
}
bool AXLayoutObject::CanHaveChildren() const {
if (!layout_object_)
return false;
return AXNodeObject::CanHaveChildren();
}
//
// Properties of the object's owning document or page.
//
double AXLayoutObject::EstimatedLoadingProgress() const {
if (!layout_object_)
return 0;
if (IsLoaded())
return 1.0;
if (LocalFrame* frame = layout_object_->GetDocument().GetFrame())
return frame->Loader().Progress().EstimatedProgress();
return 0;
}
//
// DOM and layout tree access.
//
Node* AXLayoutObject::GetNode() const {
return GetLayoutObject() ? GetLayoutObject()->GetNode() : nullptr;
}
Document* AXLayoutObject::GetDocument() const {
if (!GetLayoutObject())
return nullptr;
return &GetLayoutObject()->GetDocument();
}
LocalFrameView* AXLayoutObject::DocumentFrameView() const {
if (!GetLayoutObject())
return nullptr;
// this is the LayoutObject's Document's LocalFrame's LocalFrameView
return GetLayoutObject()->GetDocument().View();
}
Element* AXLayoutObject::AnchorElement() const {
if (!layout_object_)
return nullptr;
AXObjectCacheImpl& cache = AXObjectCache();
LayoutObject* curr_layout_object;
// Search up the layout tree for a LayoutObject with a DOM node. Defer to an
// earlier continuation, though.
for (curr_layout_object = layout_object_;
curr_layout_object && !curr_layout_object->GetNode();
curr_layout_object = curr_layout_object->Parent()) {
if (curr_layout_object->IsAnonymousBlock() &&
curr_layout_object->IsLayoutBlockFlow()) {
LayoutObject* continuation =
ToLayoutBlockFlow(curr_layout_object)->Continuation();
if (continuation)
return cache.GetOrCreate(continuation)->AnchorElement();
}
}
// bail if none found
if (!curr_layout_object)
return nullptr;
// Search up the DOM tree for an anchor element.
// NOTE: this assumes that any non-image with an anchor is an
// HTMLAnchorElement
Node* node = curr_layout_object->GetNode();
if (!node)
return nullptr;
for (Node& runner : NodeTraversal::InclusiveAncestorsOf(*node)) {
if (IsHTMLAnchorElement(runner) ||
(runner.GetLayoutObject() &&
cache.GetOrCreate(runner.GetLayoutObject())->IsAnchor()))
return ToElement(&runner);
}
return nullptr;
}
AtomicString AXLayoutObject::Language() const {
// Uses the style engine to figure out the object's language.
// The style engine relies on, for example, the "lang" attribute of the
// current node and its ancestors, and the document's "content-language"
// header. See the Language of a Node Spec at
// https://html.spec.whatwg.org/C/#language
if (!GetLayoutObject())
return AXNodeObject::Language();
const ComputedStyle* style = GetLayoutObject()->Style();
if (!style || !style->Locale())
return AXNodeObject::Language();
Vector<String> languages;
String(style->Locale()).Split(',', languages);
if (languages.IsEmpty())
return AXNodeObject::Language();
return AtomicString(languages[0].StripWhiteSpace());
}
//
// Functions that retrieve the current selection.
//
AXObject::AXSelection AXLayoutObject::Selection() const {
AXSelection text_selection = TextControlSelection();
if (text_selection.IsValid())
return text_selection;
if (!GetLayoutObject() || !GetLayoutObject()->GetFrame())
return {};
VisibleSelection selection =
GetLayoutObject()
->GetFrame()
->Selection()
.ComputeVisibleSelectionInDOMTreeDeprecated();
if (selection.IsNone())
return {};
VisiblePosition visible_start = selection.VisibleStart();
Position start = visible_start.ToParentAnchoredPosition();
TextAffinity start_affinity = visible_start.Affinity();
Node* anchor_node = start.AnchorNode();
DCHECK(anchor_node);
AXLayoutObject* anchor_object = nullptr;
// Find the closest node that has a corresponding AXObject.
// This is because some nodes may be aria hidden or might not even have
// a layout object if they are part of the shadow DOM.
while (anchor_node) {
anchor_object = GetUnignoredObjectFromNode(*anchor_node);
if (anchor_object)
break;
if (anchor_node->nextSibling())
anchor_node = anchor_node->nextSibling();
else
anchor_node = anchor_node->parentNode();
}
if (!anchor_object)
return {};
int anchor_offset = anchor_object->IndexForVisiblePosition(visible_start);
DCHECK_GE(anchor_offset, 0);
if (selection.IsCaret()) {
return {anchor_object, anchor_offset, start_affinity,
anchor_object, anchor_offset, start_affinity};
}
VisiblePosition visible_end = selection.VisibleEnd();
Position end = visible_end.ToParentAnchoredPosition();
TextAffinity end_affinity = visible_end.Affinity();
Node* focus_node = end.AnchorNode();
DCHECK(focus_node);
AXLayoutObject* focus_object = nullptr;
while (focus_node) {
focus_object = GetUnignoredObjectFromNode(*focus_node);
if (focus_object)
break;
if (focus_node->previousSibling())
focus_node = focus_node->previousSibling();
else
focus_node = focus_node->parentNode();
}
if (!focus_object)
return {};
int focus_offset = focus_object->IndexForVisiblePosition(visible_end);
DCHECK_GE(focus_offset, 0);
return {anchor_object, anchor_offset, start_affinity,
focus_object, focus_offset, end_affinity};
}
// Gets only the start and end offsets of the selection computed using the
// current object as the starting point. Returns a null selection if there is
// no selection in the subtree rooted at this object.
AXObject::AXSelection AXLayoutObject::SelectionUnderObject() const {
AXSelection text_selection = TextControlSelection();
if (text_selection.IsValid())
return text_selection;
if (!GetNode() || !GetLayoutObject()->GetFrame())
return {};
VisibleSelection selection =
GetLayoutObject()
->GetFrame()
->Selection()
.ComputeVisibleSelectionInDOMTreeDeprecated();
Range* selection_range = CreateRange(FirstEphemeralRangeOf(selection));
ContainerNode* parent_node = GetNode()->parentNode();
int node_index = GetNode()->NodeIndex();
if (!selection_range
// Selection is contained in node.
|| !(parent_node &&
selection_range->comparePoint(parent_node, node_index,
IGNORE_EXCEPTION_FOR_TESTING) < 0 &&
selection_range->comparePoint(parent_node, node_index + 1,
IGNORE_EXCEPTION_FOR_TESTING) > 0)) {
return {};
}
int start = IndexForVisiblePosition(selection.VisibleStart());
DCHECK_GE(start, 0);
int end = IndexForVisiblePosition(selection.VisibleEnd());
DCHECK_GE(end, 0);
return {start, end};
}
AXObject::AXSelection AXLayoutObject::TextControlSelection() const {
if (!GetLayoutObject())
return {};
LayoutObject* layout = nullptr;
if (GetLayoutObject()->IsTextControl()) {
layout = GetLayoutObject();
} else {
Element* focused_element = GetDocument()->FocusedElement();
if (focused_element && focused_element->GetLayoutObject() &&
focused_element->GetLayoutObject()->IsTextControl())
layout = focused_element->GetLayoutObject();
}
if (!layout)
return {};
AXObject* ax_object = AXObjectCache().GetOrCreate(layout);
if (!ax_object || !ax_object->IsAXLayoutObject())
return {};
VisibleSelection selection =
layout->GetFrame()
->Selection()
.ComputeVisibleSelectionInDOMTreeDeprecated();
TextControlElement* text_control =
ToLayoutTextControl(layout)->GetTextControlElement();
DCHECK(text_control);
int start = text_control->selectionStart();
int end = text_control->selectionEnd();
return {ax_object, start, selection.VisibleStart().Affinity(),
ax_object, end, selection.VisibleEnd().Affinity()};
}
int AXLayoutObject::IndexForVisiblePosition(
const VisiblePosition& position) const {
if (GetLayoutObject() && GetLayoutObject()->IsTextControl()) {
TextControlElement* text_control =
ToLayoutTextControl(GetLayoutObject())->GetTextControlElement();
return text_control->IndexForVisiblePosition(position);
}
if (!GetNode())
return 0;
Position index_position = position.DeepEquivalent();
if (index_position.IsNull())
return 0;
Position start_position = Position::FirstPositionInNode(*GetNode());
if (start_position > index_position) {
// TODO(chromium-accessibility): We reach here only when passing a position
// outside of the node range. This shouldn't happen, but is happening as
// found in crbug.com/756435.
LOG(WARNING) << "AX position out of node range";
return 0;
}
return TextIterator::RangeLength(start_position, index_position);
}
AXLayoutObject* AXLayoutObject::GetUnignoredObjectFromNode(Node& node) const {
if (IsDetached())
return nullptr;
AXObject* ax_object = AXObjectCache().GetOrCreate(&node);
if (!ax_object)
return nullptr;
if (ax_object->IsAXLayoutObject() && !ax_object->AccessibilityIsIgnored())
return ToAXLayoutObject(ax_object);
return nullptr;
}
//
// Modify or take an action on an object.
//
// Convert from an accessible object and offset to a VisiblePosition.
static VisiblePosition ToVisiblePosition(AXObject* obj, int offset) {
if (!obj || offset < 0)
return VisiblePosition();
// Some objects don't have an associated node, e.g. |LayoutListMarker|.
if (obj->GetLayoutObject() && !obj->GetNode() && obj->ParentObject()) {
return ToVisiblePosition(obj->ParentObject(), obj->IndexInParent());
}
if (!obj->GetNode())
return VisiblePosition();
Node* node = obj->GetNode();
if (!node->IsTextNode()) {
int child_count = obj->Children().size();
// Place position immediately before the container node, if there were no
// children.
if (child_count == 0) {
if (!obj->ParentObject())
return VisiblePosition();
return ToVisiblePosition(obj->ParentObject(), obj->IndexInParent());
}
// The offsets are child offsets over the AX tree. Note that we allow
// for the offset to equal the number of children as |Range| does.
if (offset < 0 || offset > child_count)
return VisiblePosition();
// Clamp to between 0 and child count - 1.
int clamped_offset =
static_cast<unsigned>(offset) > (obj->Children().size() - 1)
? offset - 1
: offset;
AXObject* child_obj = obj->Children()[clamped_offset];
Node* child_node = child_obj->GetNode();
// If a particular child can't be selected, expand to select the whole
// object.
if (!child_node || !child_node->parentNode())
return ToVisiblePosition(obj->ParentObject(), obj->IndexInParent());
// The index in parent.
int adjusted_offset = child_node->NodeIndex();
// If we had to clamp the offset above, the client wants to select the
// end of the node.
if (clamped_offset != offset)
adjusted_offset++;
return CreateVisiblePosition(
Position::EditingPositionOf(child_node->parentNode(), adjusted_offset));
}
// If it is a text node, we need to call some utility functions that use a
// TextIterator to walk the characters of the node and figure out the position
// corresponding to the visible character at position |offset|.
ContainerNode* parent = node->parentNode();
if (!parent)
return VisiblePosition();
VisiblePosition node_position =
CreateVisiblePosition(blink::PositionBeforeNode(*node));
int node_index = blink::IndexForVisiblePosition(node_position, parent);
return blink::VisiblePositionForIndex(node_index + offset, parent);
}
bool AXLayoutObject::OnNativeSetSelectionAction(const AXSelection& selection) {
if (!GetLayoutObject() || !selection.IsValid())
return false;
AXObject* anchor_object =
selection.anchor_object ? selection.anchor_object.Get() : this;
AXObject* focus_object =
selection.focus_object ? selection.focus_object.Get() : this;
if (!IsValidSelectionBound(anchor_object) ||
!IsValidSelectionBound(focus_object)) {
return false;
}
if (anchor_object->GetLayoutObject()->GetNode() &&
anchor_object->GetLayoutObject()->GetNode()->DispatchEvent(
*Event::CreateCancelableBubble(event_type_names::kSelectstart)) !=
DispatchEventResult::kNotCanceled)
return false;
if (!IsValidSelectionBound(anchor_object) ||
!IsValidSelectionBound(focus_object)) {
return false;
}
// The selection offsets are offsets into the accessible value.
if (anchor_object == focus_object &&
anchor_object->GetLayoutObject()->IsTextControl()) {
TextControlElement* text_control =
ToLayoutTextControl(anchor_object->GetLayoutObject())
->GetTextControlElement();
if (selection.anchor_offset <= selection.focus_offset) {
text_control->SetSelectionRange(selection.anchor_offset,
selection.focus_offset,
kSelectionHasForwardDirection);
} else {
text_control->SetSelectionRange(selection.focus_offset,
selection.anchor_offset,
kSelectionHasBackwardDirection);
}
return true;
}
LocalFrame* frame = GetLayoutObject()->GetFrame();
if (!frame || !frame->Selection().IsAvailable())
return false;
// TODO(editing-dev): Use of UpdateStyleAndLayout
// needs to be audited. see http://crbug.com/590369 for more details.
// This callsite should probably move up the stack.
frame->GetDocument()->UpdateStyleAndLayout();
// Set the selection based on visible positions, because the offsets in
// accessibility nodes are based on visible indexes, which often skips
// redundant whitespace, for example.
VisiblePosition anchor_visible_position =
ToVisiblePosition(anchor_object, selection.anchor_offset);
VisiblePosition focus_visible_position =
ToVisiblePosition(focus_object, selection.focus_offset);
if (anchor_visible_position.IsNull() || focus_visible_position.IsNull())
return false;
frame->Selection().SetSelectionAndEndTyping(
SelectionInDOMTree::Builder()
.Collapse(anchor_visible_position.ToPositionWithAffinity())
.Extend(focus_visible_position.DeepEquivalent())
.Build());
return true;
}
bool AXLayoutObject::IsValidSelectionBound(const AXObject* bound_object) const {
return GetLayoutObject() && bound_object && !bound_object->IsDetached() &&
bound_object->IsAXLayoutObject() && bound_object->GetLayoutObject() &&
bound_object->GetLayoutObject()->GetFrame() ==
GetLayoutObject()->GetFrame() &&
&bound_object->AXObjectCache() == &AXObjectCache();
}
bool AXLayoutObject::OnNativeSetValueAction(const String& string) {
if (!GetNode() || !GetNode()->IsElementNode())
return false;
if (!layout_object_ || !layout_object_->IsBoxModelObject())
return false;
LayoutBoxModelObject* layout_object = ToLayoutBoxModelObject(layout_object_);
if (layout_object->IsTextField() && IsHTMLInputElement(*GetNode())) {
ToHTMLInputElement(*GetNode())
.setValue(string, TextFieldEventBehavior::kDispatchInputAndChangeEvent);
return true;
}
if (layout_object->IsTextArea() && IsHTMLTextAreaElement(*GetNode())) {
ToHTMLTextAreaElement(*GetNode())
.setValue(string, TextFieldEventBehavior::kDispatchInputAndChangeEvent);
return true;
}
if (HasContentEditableAttributeSet()) {
ExceptionState exception_state(v8::Isolate::GetCurrent(),
ExceptionState::kExecutionContext, nullptr,
nullptr);
ToHTMLElement(GetNode())->setInnerText(string, exception_state);
if (exception_state.HadException()) {
exception_state.ClearException();
return false;
}
return true;
}
return false;
}
//
// Notifications that this object may have changed.
//
void AXLayoutObject::HandleActiveDescendantChanged() {
if (!GetLayoutObject())
return;
AXObject* focused_object = AXObjectCache().FocusedObject();
if (focused_object == this) {
AXObject* active_descendant = ActiveDescendant();
if (active_descendant && active_descendant->IsSelectedFromFocus()) {
// In single selection containers, selection follows focus, so a selection
// changed event must be fired. This ensures the AT is notified that the
// selected state has changed, so that it does not read "unselected" as
// the user navigates through the items.
AXObjectCache().HandleAriaSelectedChanged(active_descendant->GetNode());
}
// Mark this node dirty. AXEventGenerator will automatically infer
// that the active descendant changed.
AXObjectCache().MarkAXObjectDirty(this, false);
}
}
void AXLayoutObject::HandleAriaExpandedChanged() {
// Find if a parent of this object should handle aria-expanded changes.
AXObject* container_parent = this->ParentObject();
while (container_parent) {
bool found_parent = false;
switch (container_parent->RoleValue()) {
case ax::mojom::Role::kLayoutTable:
case ax::mojom::Role::kTree:
case ax::mojom::Role::kTreeGrid:
case ax::mojom::Role::kGrid:
case ax::mojom::Role::kTable:
found_parent = true;
break;
default:
break;
}
if (found_parent)
break;
container_parent = container_parent->ParentObject();
}
// Post that the row count changed.
if (container_parent) {
AXObjectCache().PostNotification(container_parent,
ax::mojom::Event::kRowCountChanged);
}
// Post that the specific row either collapsed or expanded.
AccessibilityExpanded expanded = IsExpanded();
if (!expanded)
return;
if (RoleValue() == ax::mojom::Role::kRow ||
RoleValue() == ax::mojom::Role::kTreeItem) {
ax::mojom::Event notification = ax::mojom::Event::kRowExpanded;
if (expanded == kExpandedCollapsed)
notification = ax::mojom::Event::kRowCollapsed;
AXObjectCache().PostNotification(this, notification);
} else {
AXObjectCache().PostNotification(this, ax::mojom::Event::kExpandedChanged);
}
}
void AXLayoutObject::HandleAutofillStateChanged(bool is_available) {
if (is_autofill_available_ != is_available) {
is_autofill_available_ = is_available;
AXObjectCache().MarkAXObjectDirty(this, false);
}
}
void AXLayoutObject::TextChanged() {
if (!layout_object_)
return;
Settings* settings = GetDocument()->GetSettings();
if (settings && settings->GetInlineTextBoxAccessibilityEnabled() &&
RoleValue() == ax::mojom::Role::kStaticText)
ChildrenChanged();
// Do this last - AXNodeObject::textChanged posts live region announcements,
// and we should update the inline text boxes first.
AXNodeObject::TextChanged();
}
//
// Text metrics. Most of these should be deprecated, needs major cleanup.
//
static LayoutObject* LayoutObjectFromPosition(const Position& position) {
DCHECK(position.IsNotNull());
Node* layout_object_node = nullptr;
switch (position.AnchorType()) {
case PositionAnchorType::kOffsetInAnchor:
layout_object_node = position.ComputeNodeAfterPosition();
if (!layout_object_node || !layout_object_node->GetLayoutObject())
layout_object_node = position.AnchorNode()->lastChild();
break;
case PositionAnchorType::kBeforeAnchor:
case PositionAnchorType::kAfterAnchor:
break;
case PositionAnchorType::kBeforeChildren:
layout_object_node = position.AnchorNode()->firstChild();
break;
case PositionAnchorType::kAfterChildren:
layout_object_node = position.AnchorNode()->lastChild();
break;
}
if (!layout_object_node || !layout_object_node->GetLayoutObject())
layout_object_node = position.AnchorNode();
return layout_object_node->GetLayoutObject();
}
static bool LayoutObjectContainsPosition(LayoutObject* target,
const Position& position) {
for (LayoutObject* layout_object = LayoutObjectFromPosition(position);
layout_object && layout_object->GetNode();
layout_object = layout_object->Parent()) {
if (layout_object == target)
return true;
}
return false;
}
// NOTE: Consider providing this utility method as AX API
int AXLayoutObject::Index(const VisiblePosition& position) const {
if (position.IsNull() || !IsTextControl())
return -1;
if (LayoutObjectContainsPosition(layout_object_, position.DeepEquivalent()))
return IndexForVisiblePosition(position);
return -1;
}
VisiblePosition AXLayoutObject::VisiblePositionForIndex(int index) const {
if (!layout_object_)
return VisiblePosition();
if (layout_object_->IsTextControl())
return ToLayoutTextControl(layout_object_)
->GetTextControlElement()
->VisiblePositionForIndex(index);
Node* node = layout_object_->GetNode();
if (!node)
return VisiblePosition();
if (index <= 0)
return CreateVisiblePosition(FirstPositionInOrBeforeNode(*node));
Position start, end;
bool selected = Range::selectNodeContents(node, start, end);
if (!selected)
return VisiblePosition();
CharacterIterator it(start, end);
it.Advance(index - 1);
return CreateVisiblePosition(Position(it.CurrentContainer(), it.EndOffset()),
TextAffinity::kUpstream);
}
void AXLayoutObject::AddInlineTextBoxChildren(bool force) {
Document* document = GetDocument();
if (!document)
return;
Settings* settings = document->GetSettings();
if (!force &&
(!settings || !settings->GetInlineTextBoxAccessibilityEnabled()))
return;
if (!GetLayoutObject() || !GetLayoutObject()->IsText())
return;
if (GetLayoutObject()->NeedsLayout()) {
// If a LayoutText needs layout, its inline text boxes are either
// nonexistent or invalid, so defer until the layout happens and
// the layoutObject calls AXObjectCacheImpl::inlineTextBoxesUpdated.
return;
}
LayoutText* layout_text = ToLayoutText(GetLayoutObject());
for (scoped_refptr<AbstractInlineTextBox> box =
layout_text->FirstAbstractInlineTextBox();
box.get(); box = box->NextInlineTextBox()) {
AXObject* ax_object = AXObjectCache().GetOrCreate(box.get());
if (!ax_object->AccessibilityIsIgnored())
children_.push_back(ax_object);
}
}
void AXLayoutObject::AddValidationMessageChild() {
if (!IsWebArea())
return;
AXObject* ax_object = AXObjectCache().ValidationMessageObjectIfInvalid();
if (ax_object)
children_.push_back(ax_object);
}
AXObject* AXLayoutObject::ErrorMessage() const {
// Check for aria-errormessage.
Element* existing_error_message =
GetAOMPropertyOrARIAAttribute(AOMRelationProperty::kErrorMessage);
if (existing_error_message)
return AXObjectCache().GetOrCreate(existing_error_message);
// Check for visible validationMessage. This can only be visible for a focused
// control. Corollary: if there is a visible validationMessage alert box, then
// it is related to the current focus.
if (this != AXObjectCache().FocusedObject())
return nullptr;
return AXObjectCache().ValidationMessageObjectIfInvalid();
}
void AXLayoutObject::LineBreaks(Vector<int>& line_breaks) const {
if (!IsTextControl())
return;
VisiblePosition visible_pos = VisiblePositionForIndex(0);
VisiblePosition prev_visible_pos = visible_pos;
visible_pos = NextLinePosition(visible_pos, LayoutUnit(), kHasEditableAXRole);
// nextLinePosition moves to the end of the current line when there are
// no more lines.
while (visible_pos.IsNotNull() &&
!InSameLine(prev_visible_pos, visible_pos)) {
line_breaks.push_back(IndexForVisiblePosition(visible_pos));
prev_visible_pos = visible_pos;
visible_pos =
NextLinePosition(visible_pos, LayoutUnit(), kHasEditableAXRole);
// Make sure we always make forward progress.
if (visible_pos.DeepEquivalent().CompareTo(
prev_visible_pos.DeepEquivalent()) < 0)
break;
}
}
// The following is a heuristic used to determine if a
// <table> should be with ax::mojom::Role::kTable or
// ax::mojom::Role::kLayoutTable.
bool AXLayoutObject::IsDataTable() const {
if (!layout_object_ || !GetNode())
return false;
// If it has an ARIA role, it's definitely a data table.
AtomicString role;
if (HasAOMPropertyOrARIAAttribute(AOMStringProperty::kRole, role))
return true;
if (!layout_object_->IsTable())
return false;
// When a section of the document is contentEditable, all tables should be
// treated as data tables, otherwise users may not be able to work with rich
// text editors that allow creating and editing tables.
if (GetNode() && HasEditableStyle(*GetNode()))
return true;
// If there's no node, it's definitely a layout table. This happens
// when table CSS styles are used without a complete table DOM structure.
LayoutTable* table = ToLayoutTable(layout_object_);
table->RecalcSectionsIfNeeded();
Node* table_node = table->GetNode();
if (!table_node || !IsHTMLTableElement(table_node))
return false;
// This employs a heuristic to determine if this table should appear.
// Only "data" tables should be exposed as tables.
// Unfortunately, there is no good way to determine the difference
// between a "layout" table and a "data" table.
HTMLTableElement* table_element = ToHTMLTableElement(table_node);
// If there is a caption element, summary, THEAD, or TFOOT section, it's most
// certainly a data table
if (!table_element->Summary().IsEmpty() || table_element->tHead() ||
table_element->tFoot() || table_element->caption())
return true;
// if someone used "rules" attribute than the table should appear
if (!table_element->Rules().IsEmpty())
return true;
// if there's a colgroup or col element, it's probably a data table.
if (Traversal<HTMLTableColElement>::FirstChild(*table_element))
return true;
// go through the cell's and check for tell-tale signs of "data" table status
// cells have borders, or use attributes like headers, abbr, scope or axis
table->RecalcSectionsIfNeeded();
LayoutTableSection* first_body = table->FirstBody();
if (!first_body)
return false;
int num_cols_in_first_body = first_body->NumEffectiveColumns();
int num_rows = first_body->NumRows();
// If there's only one cell, it's not a good AXTable candidate.
if (num_rows == 1 && num_cols_in_first_body == 1)
return false;
// If there are at least 20 rows, we'll call it a data table.
if (num_rows >= 20)
return true;
// Store the background color of the table to check against cell's background
// colors.
const ComputedStyle* table_style = table->Style();
if (!table_style)
return false;
Color table_bg_color =
table_style->VisitedDependentColor(GetCSSPropertyBackgroundColor());
// check enough of the cells to find if the table matches our criteria
// Criteria:
// 1) must have at least one valid cell (and)
// 2) at least half of cells have borders (or)
// 3) at least half of cells have different bg colors than the table, and
// there is cell spacing
unsigned valid_cell_count = 0;
unsigned bordered_cell_count = 0;
unsigned background_difference_cell_count = 0;
unsigned cells_with_top_border = 0;
unsigned cells_with_bottom_border = 0;
unsigned cells_with_left_border = 0;
unsigned cells_with_right_border = 0;
Color alternating_row_colors[5];
int alternating_row_color_count = 0;
for (int row = 0; row < num_rows; ++row) {
int n_cols = first_body->NumCols(row);
for (int col = 0; col < n_cols; ++col) {
LayoutTableCell* cell = first_body->PrimaryCellAt(row, col);
if (!cell)
continue;
Node* cell_node = cell->GetNode();
if (!cell_node)
continue;
if (cell->Size().Width() < 1 || cell->Size().Height() < 1)
continue;
valid_cell_count++;
// Any <th> tag -> treat as data table.
if (cell_node->HasTagName(kThTag))
return true;
// In this case, the developer explicitly assigned a "data" table
// attribute.
if (IsHTMLTableCellElement(*cell_node)) {
HTMLTableCellElement& cell_element = ToHTMLTableCellElement(*cell_node);
if (!cell_element.Headers().IsEmpty() ||
!cell_element.Abbr().IsEmpty() || !cell_element.Axis().IsEmpty() ||
!cell_element.FastGetAttribute(kScopeAttr).IsEmpty())
return true;
}
const ComputedStyle* computed_style = cell->Style();
if (!computed_style)
continue;
// If the empty-cells style is set, we'll call it a data table.
if (computed_style->EmptyCells() == EEmptyCells::kHide)
return true;
// If a cell has matching bordered sides, call it a (fully) bordered cell.
if ((cell->BorderTop() > 0 && cell->BorderBottom() > 0) ||
(cell->BorderLeft() > 0 && cell->BorderRight() > 0))
bordered_cell_count++;
// Also keep track of each individual border, so we can catch tables where
// most cells have a bottom border, for example.
if (cell->BorderTop() > 0)
cells_with_top_border++;
if (cell->BorderBottom() > 0)
cells_with_bottom_border++;
if (cell->BorderLeft() > 0)
cells_with_left_border++;
if (cell->BorderRight() > 0)
cells_with_right_border++;
// If the cell has a different color from the table and there is cell
// spacing, then it is probably a data table cell (spacing and colors take
// the place of borders).
Color cell_color = computed_style->VisitedDependentColor(
GetCSSPropertyBackgroundColor());
if (table->HBorderSpacing() > 0 && table->VBorderSpacing() > 0 &&
table_bg_color != cell_color && cell_color.Alpha() != 1)
background_difference_cell_count++;
// If we've found 10 "good" cells, we don't need to keep searching.
if (bordered_cell_count >= 10 || background_difference_cell_count >= 10)
return true;
// For the first 5 rows, cache the background color so we can check if
// this table has zebra-striped rows.
if (row < 5 && row == alternating_row_color_count) {
LayoutObject* layout_row = cell->Parent();
if (!layout_row || !layout_row->IsBoxModelObject() ||
!ToLayoutBoxModelObject(layout_row)->IsTableRow())
continue;
const ComputedStyle* row_computed_style = layout_row->Style();
if (!row_computed_style)
continue;
Color row_color = row_computed_style->VisitedDependentColor(
GetCSSPropertyBackgroundColor());
alternating_row_colors[alternating_row_color_count] = row_color;
alternating_row_color_count++;
}
}
}
// if there is less than two valid cells, it's not a data table
if (valid_cell_count <= 1)
return false;
// half of the cells had borders, it's a data table
unsigned needed_cell_count = valid_cell_count / 2;
if (bordered_cell_count >= needed_cell_count ||
cells_with_top_border >= needed_cell_count ||
cells_with_bottom_border >= needed_cell_count ||
cells_with_left_border >= needed_cell_count ||
cells_with_right_border >= needed_cell_count)
return true;
// half had different background colors, it's a data table
if (background_difference_cell_count >= needed_cell_count)
return true;
// Check if there is an alternating row background color indicating a zebra
// striped style pattern.
if (alternating_row_color_count > 2) {
Color first_color = alternating_row_colors[0];
for (int k = 1; k < alternating_row_color_count; k++) {
// If an odd row was the same color as the first row, its not alternating.
if (k % 2 == 1 && alternating_row_colors[k] == first_color)
return false;
// If an even row is not the same as the first row, its not alternating.
if (!(k % 2) && alternating_row_colors[k] != first_color)
return false;
}
return true;
}
return false;
}
unsigned AXLayoutObject::ColumnCount() const {
if (AriaRoleAttribute() != ax::mojom::Role::kUnknown)
return AXNodeObject::ColumnCount();
LayoutObject* layout_object = GetLayoutObject();
if (!layout_object || !layout_object->IsTable() || !layout_object->GetNode())
return AXNodeObject::ColumnCount();
LayoutTable* table = ToLayoutTable(layout_object);
table->RecalcSectionsIfNeeded();
LayoutTableSection* table_section = table->TopSection();
if (!table_section)
return AXNodeObject::ColumnCount();
return table_section->NumEffectiveColumns();
}
unsigned AXLayoutObject::RowCount() const {
if (AriaRoleAttribute() != ax::mojom::Role::kUnknown)
return AXNodeObject::RowCount();
LayoutObject* layout_object = GetLayoutObject();
if (!layout_object || !layout_object->IsTable() || !layout_object->GetNode())
return AXNodeObject::RowCount();
LayoutTable* table = ToLayoutTable(layout_object);
table->RecalcSectionsIfNeeded();
unsigned row_count = 0;
LayoutTableSection* table_section = table->TopSection();
if (!table_section)
return AXNodeObject::RowCount();
while (table_section) {
row_count += table_section->NumRows();
table_section = table->SectionBelow(table_section, kSkipEmptySections);
}
return row_count;
}
unsigned AXLayoutObject::ColumnIndex() const {
LayoutObject* layout_object = GetLayoutObject();
if (!layout_object || !layout_object->GetNode())
return AXNodeObject::ColumnIndex();
if (layout_object->IsTableCell()) {
LayoutTableCell* cell = ToLayoutTableCell(layout_object);
return cell->Table()->AbsoluteColumnToEffectiveColumn(
cell->AbsoluteColumnIndex());
}
return AXNodeObject::ColumnIndex();
}
unsigned AXLayoutObject::RowIndex() const {
LayoutObject* layout_object = GetLayoutObject();
if (!layout_object || !layout_object->GetNode())
return AXNodeObject::RowIndex();
unsigned row_index = 0;
LayoutTableSection* row_section = nullptr;
LayoutTable* table = nullptr;
if (layout_object->IsTableRow()) {
LayoutTableRow* row = ToLayoutTableRow(layout_object);
row_index = row->RowIndex();
row_section = row->Section();
table = row->Table();
} else if (layout_object->IsTableCell()) {
LayoutTableCell* cell = ToLayoutTableCell(layout_object);
row_index = cell->RowIndex();
row_section = cell->Section();
table = cell->Table();
} else {
return AXNodeObject::RowIndex();
}
if (!table || !row_section)
return AXNodeObject::RowIndex();
// Since our table might have multiple sections, we have to offset our row
// appropriately.
table->RecalcSectionsIfNeeded();
LayoutTableSection* section = table->TopSection();
while (section && section != row_section) {
row_index += section->NumRows();
section = table->SectionBelow(section, kSkipEmptySections);
}
return row_index;
}
unsigned AXLayoutObject::ColumnSpan() const {
LayoutObject* layout_object = GetLayoutObject();
if (!layout_object || !layout_object->IsTableCell())
return AXNodeObject::ColumnSpan();
LayoutTableCell* cell = ToLayoutTableCell(layout_object);
unsigned absolute_first_col = cell->AbsoluteColumnIndex();
unsigned absolute_last_col = absolute_first_col + cell->ColSpan() - 1;
unsigned effective_first_col =
cell->Table()->AbsoluteColumnToEffectiveColumn(absolute_first_col);
unsigned effective_last_col =
cell->Table()->AbsoluteColumnToEffectiveColumn(absolute_last_col);
return effective_last_col - effective_first_col + 1;
}
unsigned AXLayoutObject::RowSpan() const {
LayoutObject* layout_object = GetLayoutObject();
if (!layout_object || !layout_object->IsTableCell())
return AXNodeObject::ColumnSpan();
LayoutTableCell* cell = ToLayoutTableCell(layout_object);
return cell->ResolvedRowSpan();
}
ax::mojom::SortDirection AXLayoutObject::GetSortDirection() const {
if (RoleValue() != ax::mojom::Role::kRowHeader &&
RoleValue() != ax::mojom::Role::kColumnHeader)
return ax::mojom::SortDirection::kNone;
const AtomicString& aria_sort =
GetAOMPropertyOrARIAAttribute(AOMStringProperty::kSort);
if (aria_sort.IsEmpty())
return ax::mojom::SortDirection::kNone;
if (EqualIgnoringASCIICase(aria_sort, "none"))
return ax::mojom::SortDirection::kNone;
if (EqualIgnoringASCIICase(aria_sort, "ascending"))
return ax::mojom::SortDirection::kAscending;
if (EqualIgnoringASCIICase(aria_sort, "descending"))
return ax::mojom::SortDirection::kDescending;
// Technically, illegal values should be exposed as is, but this does
// not seem to be worth the implementation effort at this time.
return ax::mojom::SortDirection::kOther;
}
static bool IsNonEmptyNonHeaderCell(LayoutTableCell* cell) {
if (!cell)
return false;
if (Node* node = cell->GetNode())
return node->hasChildren() && node->HasTagName(kTdTag);
return false;
}
static bool IsHeaderCell(LayoutTableCell* cell) {
if (!cell)
return false;
if (Node* node = cell->GetNode())
return node->HasTagName(kThTag);
return false;
}
static ax::mojom::Role DecideRoleFromSiblings(LayoutTableCell* cell) {
if (!IsHeaderCell(cell))
return ax::mojom::Role::kCell;
// If this header is only cell in its row, it is a column header.
// It is also a column header if it has a header on either side of it.
// If instead it has a non-empty td element next to it, it is a row header.
LayoutTableCell* next_cell = cell->NextCell();
LayoutTableCell* previous_cell = cell->PreviousCell();
if (!next_cell && !previous_cell)
return ax::mojom::Role::kColumnHeader;
if (IsHeaderCell(next_cell) && IsHeaderCell(previous_cell))
return ax::mojom::Role::kColumnHeader;
if (IsNonEmptyNonHeaderCell(next_cell) ||
IsNonEmptyNonHeaderCell(previous_cell))
return ax::mojom::Role::kRowHeader;
LayoutTableRow* layout_row = cell->Row();
DCHECK(layout_row);
// If this row's first or last cell is a non-empty td, this is a row header.
// Do the same check for the second and second-to-last cells because tables
// often have an empty cell at the intersection of the row and column headers.
LayoutTableCell* first_cell = layout_row->FirstCell();
DCHECK(first_cell);
LayoutTableCell* last_cell = layout_row->LastCell();
DCHECK(last_cell);
if (IsNonEmptyNonHeaderCell(first_cell) || IsNonEmptyNonHeaderCell(last_cell))
return ax::mojom::Role::kRowHeader;
if (IsNonEmptyNonHeaderCell(first_cell->NextCell()) ||
IsNonEmptyNonHeaderCell(last_cell->PreviousCell()))
return ax::mojom::Role::kRowHeader;
// We have no evidence that this is not a column header.
return ax::mojom::Role::kColumnHeader;
}
ax::mojom::Role AXLayoutObject::DetermineTableRowRole() const {
AXObject* parent = ParentObjectUnignored();
if (!parent)
return ax::mojom::Role::kGenericContainer;
if (parent->GetLayoutObject()->IsTableSection())
parent = parent->ParentObjectUnignored();
if (parent->RoleValue() == ax::mojom::Role::kLayoutTable)
return ax::mojom::Role::kLayoutTableRow;
if (parent->IsTableLikeRole())
return ax::mojom::Role::kRow;
return ax::mojom::Role::kGenericContainer;
}
ax::mojom::Role AXLayoutObject::DetermineTableCellRole() const {
DCHECK(layout_object_);
AXObject* parent = ParentObjectUnignored();
if (!parent || !parent->IsTableRowLikeRole())
return ax::mojom::Role::kGenericContainer;
AXObject* grandparent = parent->ParentObjectUnignored();
if (grandparent && grandparent->GetLayoutObject()->IsTableSection())
grandparent = grandparent->ParentObjectUnignored();
if (!grandparent || !grandparent->IsTableLikeRole())
return ax::mojom::Role::kGenericContainer;
if (parent->RoleValue() == ax::mojom::Role::kLayoutTableRow)
return ax::mojom::Role::kLayoutTableCell;
if (!parent->IsTableRowLikeRole())
return ax::mojom::Role::kGenericContainer;
if (!GetNode() || !GetNode()->HasTagName(kThTag))
return ax::mojom::Role::kCell;
const AtomicString& scope = GetAttribute(kScopeAttr);
if (EqualIgnoringASCIICase(scope, "row") ||
EqualIgnoringASCIICase(scope, "rowgroup"))
return ax::mojom::Role::kRowHeader;
if (EqualIgnoringASCIICase(scope, "col") ||
EqualIgnoringASCIICase(scope, "colgroup"))
return ax::mojom::Role::kColumnHeader;
return DecideRoleFromSiblings(ToLayoutTableCell(layout_object_));
}
AXObject* AXLayoutObject::CellForColumnAndRow(unsigned target_column_index,
unsigned target_row_index) const {
LayoutObject* layout_object = GetLayoutObject();
if (!layout_object || !layout_object->IsTable()) {
return AXNodeObject::CellForColumnAndRow(target_column_index,
target_row_index);
}
LayoutTable* table = ToLayoutTable(layout_object);
table->RecalcSectionsIfNeeded();
LayoutTableSection* table_section = table->TopSection();
if (!table_section) {
return AXNodeObject::CellForColumnAndRow(target_column_index,
target_row_index);
}
unsigned row_offset = 0;
while (table_section) {
// Iterate backwards through the rows in case the desired cell has a rowspan
// and exists in a previous row.
for (LayoutTableRow* row = table_section->LastRow(); row;
row = row->PreviousRow()) {
unsigned row_index = row->RowIndex() + row_offset;
for (LayoutTableCell* cell = row->LastCell(); cell;
cell = cell->PreviousCell()) {
unsigned absolute_first_col = cell->AbsoluteColumnIndex();
unsigned absolute_last_col = absolute_first_col + cell->ColSpan() - 1;
unsigned effective_first_col =
cell->Table()->AbsoluteColumnToEffectiveColumn(absolute_first_col);
unsigned effective_last_col =
cell->Table()->AbsoluteColumnToEffectiveColumn(absolute_last_col);
unsigned row_span = cell->ResolvedRowSpan();
if (target_column_index >= effective_first_col &&
target_column_index <= effective_last_col &&
target_row_index >= row_index &&
target_row_index < row_index + row_span) {
return AXObjectCache().GetOrCreate(cell);
}
}
}
row_offset += table_section->NumRows();
table_section = table->SectionBelow(table_section, kSkipEmptySections);
}
return nullptr;
}
bool AXLayoutObject::FindAllTableCellsWithRole(ax::mojom::Role role,
AXObjectVector& cells) const {
LayoutObject* layout_object = GetLayoutObject();
if (!layout_object || !layout_object->IsTable())
return false;
LayoutTable* table = ToLayoutTable(layout_object);
table->RecalcSectionsIfNeeded();
LayoutTableSection* table_section = table->TopSection();
if (!table_section)
return true;
while (table_section) {
for (LayoutTableRow* row = table_section->FirstRow(); row;
row = row->NextRow()) {
for (LayoutTableCell* cell = row->FirstCell(); cell;
cell = cell->NextCell()) {
AXObject* ax_cell = AXObjectCache().GetOrCreate(cell);
if (ax_cell && ax_cell->RoleValue() == role)
cells.push_back(ax_cell);
}
}
table_section = table->SectionBelow(table_section, kSkipEmptySections);
}
return true;
}
void AXLayoutObject::ColumnHeaders(AXObjectVector& headers) const {
if (!FindAllTableCellsWithRole(ax::mojom::Role::kColumnHeader, headers))
AXNodeObject::ColumnHeaders(headers);
}
void AXLayoutObject::RowHeaders(AXObjectVector& headers) const {
if (!FindAllTableCellsWithRole(ax::mojom::Role::kRowHeader, headers))
AXNodeObject::RowHeaders(headers);
}
AXObject* AXLayoutObject::HeaderObject() const {
LayoutObject* layout_object = GetLayoutObject();
if (!layout_object || !layout_object->IsTableRow())
return nullptr;
LayoutTableRow* row = ToLayoutTableRow(layout_object);
for (LayoutTableCell* cell = row->FirstCell(); cell;
cell = cell->NextCell()) {
AXObject* ax_cell = AXObjectCache().GetOrCreate(cell);
if (ax_cell && ax_cell->RoleValue() == ax::mojom::Role::kRowHeader)
return ax_cell;
}
return nullptr;
}
//
// Private.
//
bool AXLayoutObject::IsTabItemSelected() const {
if (!IsTabItem() || !GetLayoutObject())
return false;
Node* node = GetNode();
if (!node || !node->IsElementNode())
return false;
// The ARIA spec says a tab item can also be selected if it is aria-labeled by
// a tabpanel that has keyboard focus inside of it, or if a tabpanel in its
// aria-controls list has KB focus inside of it.
AXObject* focused_element = AXObjectCache().FocusedObject();
if (!focused_element)
return false;
HeapVector<Member<Element>> elements;
if (!HasAOMPropertyOrARIAAttribute(AOMRelationListProperty::kControls,
elements))
return false;
for (const auto& element : elements) {
AXObject* tab_panel = AXObjectCache().GetOrCreate(element);
// A tab item should only control tab panels.
if (!tab_panel || tab_panel->RoleValue() != ax::mojom::Role::kTabPanel)
continue;
AXObject* check_focus_element = focused_element;
// Check if the focused element is a descendant of the element controlled by
// the tab item.
while (check_focus_element) {
if (tab_panel == check_focus_element)
return true;
check_focus_element = check_focus_element->ParentObject();
}
}
return false;
}
AXObject* AXLayoutObject::AccessibilityImageMapHitTest(
HTMLAreaElement* area,
const IntPoint& point) const {
if (!area)
return nullptr;
AXObject* parent = AXObjectCache().GetOrCreate(area->ImageElement());
if (!parent)
return nullptr;
for (const auto& child : parent->Children()) {
if (child->GetBoundsInFrameCoordinates().Contains(point))
return child.Get();
}
return nullptr;
}
bool AXLayoutObject::IsSVGImage() const {
return RemoteSVGRootElement();
}
void AXLayoutObject::DetachRemoteSVGRoot() {
if (AXSVGRoot* root = RemoteSVGRootElement())
root->SetParent(nullptr);
}
AXSVGRoot* AXLayoutObject::RemoteSVGRootElement() const {
// FIXME(dmazzoni): none of this code properly handled multiple references to
// the same remote SVG document. I'm disabling this support until it can be
// fixed properly.
return nullptr;
}
AXObject* AXLayoutObject::RemoteSVGElementHitTest(const IntPoint& point) const {
AXObject* remote = RemoteSVGRootElement();
if (!remote)
return nullptr;
IntSize offset =
point - RoundedIntPoint(GetBoundsInFrameCoordinates().Location());
return remote->AccessibilityHitTest(IntPoint(offset));
}
// The boundingBox for elements within the remote SVG element needs to be offset
// by its position within the parent page, otherwise they are in relative
// coordinates only.
void AXLayoutObject::OffsetBoundingBoxForRemoteSVGElement(
LayoutRect& rect) const {
for (AXObject* parent = ParentObject(); parent;
parent = parent->ParentObject()) {
if (parent->IsAXSVGRoot()) {
rect.MoveBy(
parent->ParentObject()->GetBoundsInFrameCoordinates().Location());
break;
}
}
}
// Hidden children are those that are not laid out or visible, but are
// specifically marked as aria-hidden=false,
// meaning that they should be exposed to the AX hierarchy.
void AXLayoutObject::AddHiddenChildren() {
Node* node = this->GetNode();
if (!node)
return;
// First do a quick run through to determine if we have any hidden nodes (most
// often we will not). If we do have hidden nodes, we need to determine where
// to insert them so they match DOM order as close as possible.
bool should_insert_hidden_nodes = false;
for (Node& child : NodeTraversal::ChildrenOf(*node)) {
if (!child.GetLayoutObject() && IsNodeAriaVisible(&child)) {
should_insert_hidden_nodes = true;
break;
}
}
if (!should_insert_hidden_nodes)
return;
// Iterate through all of the children, including those that may have already
// been added, and try to insert hidden nodes in the correct place in the DOM
// order.
unsigned insertion_index = 0;
for (Node& child : NodeTraversal::ChildrenOf(*node)) {
if (child.GetLayoutObject()) {
// Find out where the last layout sibling is located within m_children.
if (AXObject* child_object =
AXObjectCache().Get(child.GetLayoutObject())) {
if (child_object->AccessibilityIsIgnored()) {
const auto& children = child_object->Children();
child_object = children.size() ? children.back().Get() : nullptr;
}
if (child_object)
insertion_index = children_.Find(child_object) + 1;
continue;
}
}
if (!IsNodeAriaVisible(&child))
continue;
unsigned previous_size = children_.size();
if (insertion_index > previous_size)
insertion_index = previous_size;
InsertChild(AXObjectCache().GetOrCreate(&child), insertion_index);
insertion_index += (children_.size() - previous_size);
}
}
void AXLayoutObject::AddImageMapChildren() {
LayoutBoxModelObject* css_box = GetLayoutBoxModelObject();
if (!css_box || !css_box->IsLayoutImage())
return;
HTMLMapElement* map = ToLayoutImage(css_box)->ImageMap();
if (!map)
return;
for (HTMLAreaElement& area :
Traversal<HTMLAreaElement>::DescendantsOf(*map)) {
// add an <area> element for this child if it has a link
AXObject* obj = AXObjectCache().GetOrCreate(&area);
if (obj) {
AXImageMapLink* area_object = ToAXImageMapLink(obj);
area_object->SetParent(this);
DCHECK_NE(area_object->AXObjectID(), 0U);
if (!area_object->AccessibilityIsIgnored())
children_.push_back(area_object);
else
AXObjectCache().Remove(area_object->AXObjectID());
}
}
}
void AXLayoutObject::AddPopupChildren() {
if (!IsHTMLInputElement(GetNode()))
return;
if (AXObject* ax_popup = ToHTMLInputElement(GetNode())->PopupRootAXObject())
children_.push_back(ax_popup);
}
void AXLayoutObject::AddRemoteSVGChildren() {
AXSVGRoot* root = RemoteSVGRootElement();
if (!root)
return;
root->SetParent(this);
if (root->AccessibilityIsIgnored()) {
for (const auto& child : root->Children())
children_.push_back(child);
} else {
children_.push_back(root);
}
}
void AXLayoutObject::AddTableChildren() {
if (!IsTableLikeRole())
return;
AXObjectCacheImpl& ax_cache = AXObjectCache();
if (layout_object_->IsTable()) {
LayoutTable* table = ToLayoutTable(layout_object_);
table->RecalcSectionsIfNeeded();
Node* table_node = table->GetNode();
if (IsHTMLTableElement(table_node)) {
if (HTMLTableCaptionElement* caption =
ToHTMLTableElement(table_node)->caption()) {
AXObject* caption_object = ax_cache.GetOrCreate(caption);
if (caption_object && !caption_object->AccessibilityIsIgnored())
children_.push_front(caption_object);
}
}
}
}
} // namespace blink