chromium/src/third_party/blink/renderer/modules/accessibility/ax_menu_list.cc

/*
 * Copyright (C) 2010 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.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``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 INC. OR
 * 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_menu_list.h"

#include "third_party/blink/renderer/core/html/forms/html_select_element.h"
#include "third_party/blink/renderer/core/layout/layout_object.h"
#include "third_party/blink/renderer/modules/accessibility/ax_menu_list_popup.h"
#include "third_party/blink/renderer/modules/accessibility/ax_object_cache_impl.h"

namespace blink {

AXMenuList::AXMenuList(LayoutObject* layout_object,
                       AXObjectCacheImpl& ax_object_cache)
    : AXLayoutObject(layout_object, ax_object_cache) {
  DCHECK(IsA<HTMLSelectElement>(layout_object->GetNode()));
}

ax::mojom::Role AXMenuList::DetermineAccessibilityRole() {
  if ((aria_role_ = DetermineAriaRoleAttribute()) != ax::mojom::Role::kUnknown)
    return aria_role_;

  return ax::mojom::Role::kPopUpButton;
}

bool AXMenuList::OnNativeClickAction() {
  if (!layout_object_)
    return false;

  HTMLSelectElement* select = To<HTMLSelectElement>(GetNode());
  if (select->PopupIsVisible())
    select->HidePopup();
  else
    select->ShowPopup();
  return true;
}

void AXMenuList::Detach() {
  // Detach() calls ClearChildren(), but AXMenuList::ClearChildren()
  // detaches the grandchild options, not the child option.
  AXLayoutObject::Detach();
  DCHECK_LE(children_.size(), 1U);

  // Clear the popup.
  if (children_.size()) {
    children_[0]->DetachFromParent();
    // Unfortunately, the popup will be left hanging around until
    // AXObjectCacheImpl() is reset. We cannot remove it here because
    // this can be called while AXObjectCacheImpl() is detaching all objects,
    // and the hash map of objects does not allow similtaneous iteration and
    // removal of objects.
    // TODO(accessibility) Consider something like this, or something that
    // marks the object for imminent diposal.
    // if (!AXObjectCache().IsDisposing()
    //   children_[0]->AXObjectCache().Remove(children_[0]);
    children_[0]->Detach();
    children_.clear();
  }
}

void AXMenuList::ClearChildren() const {
  if (children_.IsEmpty())
    return;

  // Unless the menu list is detached, there's no reason to clear our
  // AXMenuListPopup child. If we get a call to clearChildren, it's because the
  // options might have changed, so call it on our popup. Clearing the
  // AXMenuListPopup child would cause additional thrashing and events that the
  // AT would need to process, potentially causing the AT to believe that the
  // popup had closed and a new popup and reopened.
  // The mock AXMenuListPopup child will be cleared when this object is
  // detached, as it has no use without this object as an owner.
  DCHECK_EQ(children_.size(), 1U);
  children_[0]->ClearChildren();
}

void AXMenuList::AddChildren() {
#if DCHECK_IS_ON()
  DCHECK(!IsDetached());
  DCHECK(!is_adding_children_) << " Reentering method on " << GetNode();
  base::AutoReset<bool> reentrancy_protector(&is_adding_children_, true);
  // ClearChildren() does not clear the menulist popup chld.
  DCHECK_LE(children_.size(), 1U)
      << "Parent still has " << children_.size() << " children before adding:"
      << "\nParent is " << ToString(true, true) << "\nFirst child is "
      << children_[0]->ToString(true, true);
#endif

  DCHECK(children_dirty_);
  children_dirty_ = false;

  // Ensure mock AXMenuListPopup exists.
  if (children_.IsEmpty()) {
    AXObjectCacheImpl& cache = AXObjectCache();
    AXObject* popup =
        cache.CreateAndInit(ax::mojom::blink::Role::kMenuListPopup, this);
    DCHECK(popup);
    DCHECK(!popup->IsDetached());
    DCHECK(popup->CachedParentObject());
    children_.push_back(popup);
  }

  // Update mock AXMenuListPopup children.
  children_[0]->SetNeedsToUpdateChildren();
  children_[0]->UpdateChildrenIfNecessary();
}

bool AXMenuList::IsCollapsed() const {
  // Collapsed is the "default" state, so if the LayoutObject doesn't exist
  // this makes slightly more sense than returning false.
  if (!layout_object_)
    return true;

  return !To<HTMLSelectElement>(GetNode())->PopupIsVisible();
}

AccessibilityExpanded AXMenuList::IsExpanded() const {
  if (IsCollapsed())
    return kExpandedCollapsed;

  return kExpandedExpanded;
}

void AXMenuList::DidUpdateActiveOption(int option_index) {
  bool suppress_notifications =
      (GetNode() && !GetNode()->IsFinishedParsingChildren());

  // TODO(aleventhal) The  NeedsToUpdateChildren() check is necessary to avoid a
  // illegal lifecycle while adding children, since this can be called at any
  // time by AXObjectCacheImpl(). Look into calling with clean layout.
  if (!NeedsToUpdateChildren()) {
    const auto& child_objects = ChildrenIncludingIgnored();
    if (!child_objects.IsEmpty()) {
      DCHECK_EQ(child_objects.size(), 1ul);
      DCHECK(IsA<AXMenuListPopup>(child_objects[0].Get()));

      if (auto* popup = DynamicTo<AXMenuListPopup>(child_objects[0].Get()))
        popup->DidUpdateActiveOption(option_index, !suppress_notifications);
    }
  }

  AXObjectCache().PostNotification(this,
                                   ax::mojom::Event::kMenuListValueChanged);
}

void AXMenuList::DidShowPopup() {
  if (ChildCountIncludingIgnored() != 1)
    return;

  auto* popup = To<AXMenuListPopup>(ChildAtIncludingIgnored(0));
  popup->DidShow();
}

void AXMenuList::DidHidePopup() {
  if (ChildCountIncludingIgnored() != 1)
    return;

  auto* popup = To<AXMenuListPopup>(ChildAtIncludingIgnored(0));
  popup->DidHide();

  if (GetNode() && GetNode()->IsFocused())
    AXObjectCache().PostNotification(this, ax::mojom::Event::kFocus);
}

}  // namespace blink