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-rw-r--r--accessible/android/TraversalRule.cpp290
1 files changed, 290 insertions, 0 deletions
diff --git a/accessible/android/TraversalRule.cpp b/accessible/android/TraversalRule.cpp
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+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "TraversalRule.h"
+
+#include "mozilla/ArrayUtils.h"
+#include "mozilla/a11y/Accessible.h"
+
+#include "Role.h"
+#include "HTMLListAccessible.h"
+#include "SessionAccessibility.h"
+#include "nsAccUtils.h"
+#include "nsIAccessiblePivot.h"
+
+using namespace mozilla;
+using namespace mozilla::a11y;
+
+TraversalRule::TraversalRule()
+ : TraversalRule(java::SessionAccessibility::HTML_GRANULARITY_DEFAULT,
+ true) {}
+
+TraversalRule::TraversalRule(int32_t aGranularity, bool aIsLocal)
+ : mGranularity(aGranularity), mIsLocal(aIsLocal) {}
+
+uint16_t TraversalRule::Match(Accessible* aAcc) {
+ MOZ_ASSERT(aAcc);
+
+ if (mIsLocal && aAcc->IsRemote()) {
+ // If we encounter a remote accessible in a local rule, we should
+ // ignore the subtree because we won't encounter anymore local accessibles
+ // in it.
+ return nsIAccessibleTraversalRule::FILTER_IGNORE |
+ nsIAccessibleTraversalRule::FILTER_IGNORE_SUBTREE;
+ } else if (!mIsLocal && aAcc->IsLocal()) {
+ // If we encounter a local accessible in a remote rule we are likely
+ // traversing backwards/upwards, we don't ignore its subtree because it is
+ // likely the outer doc root of the remote tree.
+ return nsIAccessibleTraversalRule::FILTER_IGNORE;
+ }
+
+ uint16_t result = nsIAccessibleTraversalRule::FILTER_IGNORE;
+
+ if (nsAccUtils::MustPrune(aAcc)) {
+ result |= nsIAccessibleTraversalRule::FILTER_IGNORE_SUBTREE;
+ }
+
+ uint64_t state = aAcc->State();
+
+ if ((state & states::INVISIBLE) != 0) {
+ return result;
+ }
+
+ if (aAcc->Opacity() == 0.0f) {
+ return result | nsIAccessibleTraversalRule::FILTER_IGNORE_SUBTREE;
+ }
+
+ switch (mGranularity) {
+ case java::SessionAccessibility::HTML_GRANULARITY_LINK:
+ result |= LinkMatch(aAcc);
+ break;
+ case java::SessionAccessibility::HTML_GRANULARITY_CONTROL:
+ result |= ControlMatch(aAcc);
+ break;
+ case java::SessionAccessibility::HTML_GRANULARITY_SECTION:
+ result |= SectionMatch(aAcc);
+ break;
+ case java::SessionAccessibility::HTML_GRANULARITY_HEADING:
+ result |= HeadingMatch(aAcc);
+ break;
+ case java::SessionAccessibility::HTML_GRANULARITY_LANDMARK:
+ result |= LandmarkMatch(aAcc);
+ break;
+ default:
+ result |= DefaultMatch(aAcc);
+ break;
+ }
+
+ return result;
+}
+
+bool TraversalRule::IsSingleLineage(Accessible* aAccessible) {
+ Accessible* child = aAccessible;
+ while (child) {
+ switch (child->ChildCount()) {
+ case 0:
+ return true;
+ case 1:
+ child = child->FirstChild();
+ break;
+ case 2:
+ if (IsListItemBullet(child->FirstChild())) {
+ child = child->LastChild();
+ } else {
+ return false;
+ }
+ break;
+ default:
+ return false;
+ }
+ }
+
+ return true;
+}
+
+bool TraversalRule::IsListItemBullet(const Accessible* aAccessible) {
+ return aAccessible->Role() == roles::LISTITEM_MARKER;
+}
+
+bool TraversalRule::IsFlatSubtree(const Accessible* aAccessible) {
+ for (auto child = aAccessible->FirstChild(); child;
+ child = child->NextSibling()) {
+ roles::Role role = child->Role();
+ if (role == roles::TEXT_LEAF || role == roles::STATICTEXT) {
+ continue;
+ }
+
+ if (child->ChildCount() > 0 || child->ActionCount() > 0) {
+ return false;
+ }
+ }
+
+ return true;
+}
+
+bool TraversalRule::HasName(const Accessible* aAccessible) {
+ nsAutoString name;
+ aAccessible->Name(name);
+ name.CompressWhitespace();
+ return !name.IsEmpty();
+}
+
+uint16_t TraversalRule::LinkMatch(Accessible* aAccessible) {
+ if (aAccessible->Role() == roles::LINK &&
+ (aAccessible->State() & states::LINKED) != 0) {
+ return nsIAccessibleTraversalRule::FILTER_MATCH |
+ nsIAccessibleTraversalRule::FILTER_IGNORE_SUBTREE;
+ }
+
+ return nsIAccessibleTraversalRule::FILTER_IGNORE;
+}
+
+uint16_t TraversalRule::HeadingMatch(Accessible* aAccessible) {
+ if (aAccessible->Role() == roles::HEADING && aAccessible->ChildCount()) {
+ return nsIAccessibleTraversalRule::FILTER_MATCH;
+ }
+
+ return nsIAccessibleTraversalRule::FILTER_IGNORE;
+}
+
+uint16_t TraversalRule::SectionMatch(Accessible* aAccessible) {
+ roles::Role role = aAccessible->Role();
+ if (role == roles::HEADING || role == roles::LANDMARK ||
+ aAccessible->LandmarkRole()) {
+ return nsIAccessibleTraversalRule::FILTER_MATCH;
+ }
+
+ return nsIAccessibleTraversalRule::FILTER_IGNORE;
+}
+
+uint16_t TraversalRule::LandmarkMatch(Accessible* aAccessible) {
+ if (aAccessible->LandmarkRole()) {
+ return nsIAccessibleTraversalRule::FILTER_MATCH;
+ }
+
+ return nsIAccessibleTraversalRule::FILTER_IGNORE;
+}
+
+uint16_t TraversalRule::ControlMatch(Accessible* aAccessible) {
+ switch (aAccessible->Role()) {
+ case roles::PUSHBUTTON:
+ case roles::SPINBUTTON:
+ case roles::TOGGLE_BUTTON:
+ case roles::BUTTONDROPDOWN:
+ case roles::BUTTONDROPDOWNGRID:
+ case roles::COMBOBOX:
+ case roles::LISTBOX:
+ case roles::ENTRY:
+ case roles::PASSWORD_TEXT:
+ case roles::PAGETAB:
+ case roles::RADIOBUTTON:
+ case roles::RADIO_MENU_ITEM:
+ case roles::SLIDER:
+ case roles::CHECKBUTTON:
+ case roles::CHECK_MENU_ITEM:
+ case roles::SWITCH:
+ case roles::MENUITEM:
+ return nsIAccessibleTraversalRule::FILTER_MATCH |
+ nsIAccessibleTraversalRule::FILTER_IGNORE_SUBTREE;
+ case roles::LINK:
+ return LinkMatch(aAccessible);
+ case roles::EDITCOMBOBOX:
+ if (aAccessible->State() & states::EDITABLE) {
+ // Only match ARIA 1.0 comboboxes; i.e. where the combobox itself is
+ // editable. If it's a 1.1 combobox, the combobox is just a container;
+ // we want to stop on the textbox inside it, not the container.
+ return nsIAccessibleTraversalRule::FILTER_MATCH |
+ nsIAccessibleTraversalRule::FILTER_IGNORE_SUBTREE;
+ }
+ break;
+ default:
+ break;
+ }
+
+ return nsIAccessibleTraversalRule::FILTER_IGNORE;
+}
+
+uint16_t TraversalRule::DefaultMatch(Accessible* aAccessible) {
+ switch (aAccessible->Role()) {
+ case roles::COMBOBOX:
+ // We don't want to ignore the subtree because this is often
+ // where the list box hangs out.
+ return nsIAccessibleTraversalRule::FILTER_MATCH;
+ case roles::EDITCOMBOBOX:
+ if (aAccessible->State() & states::EDITABLE) {
+ // Only match ARIA 1.0 comboboxes; i.e. where the combobox itself is
+ // editable. If it's a 1.1 combobox, the combobox is just a container;
+ // we want to stop on the textbox inside it.
+ return nsIAccessibleTraversalRule::FILTER_MATCH;
+ }
+ break;
+ case roles::TEXT_LEAF:
+ case roles::GRAPHIC:
+ // Nameless text leaves are boring, skip them.
+ if (HasName(aAccessible)) {
+ return nsIAccessibleTraversalRule::FILTER_MATCH;
+ }
+ break;
+ case roles::STATICTEXT:
+ // Ignore list bullets
+ if (!IsListItemBullet(aAccessible)) {
+ return nsIAccessibleTraversalRule::FILTER_MATCH;
+ }
+ break;
+ case roles::HEADER:
+ case roles::HEADING:
+ case roles::COLUMNHEADER:
+ case roles::ROWHEADER:
+ case roles::STATUSBAR:
+ if ((aAccessible->ChildCount() > 0 || HasName(aAccessible)) &&
+ (IsSingleLineage(aAccessible) || IsFlatSubtree(aAccessible))) {
+ return nsIAccessibleTraversalRule::FILTER_MATCH |
+ nsIAccessibleTraversalRule::FILTER_IGNORE_SUBTREE;
+ }
+ break;
+ case roles::GRID_CELL:
+ if (IsSingleLineage(aAccessible) || IsFlatSubtree(aAccessible)) {
+ return nsIAccessibleTraversalRule::FILTER_MATCH |
+ nsIAccessibleTraversalRule::FILTER_IGNORE_SUBTREE;
+ }
+ break;
+ case roles::LABEL:
+ if (IsFlatSubtree(aAccessible)) {
+ // Match if this is a label with text but no nested controls.
+ return nsIAccessibleTraversalRule::FILTER_MATCH |
+ nsIAccessibleTraversalRule::FILTER_IGNORE_SUBTREE;
+ }
+ break;
+ case roles::MENUITEM:
+ case roles::LINK:
+ case roles::PAGETAB:
+ case roles::PUSHBUTTON:
+ case roles::CHECKBUTTON:
+ case roles::RADIOBUTTON:
+ case roles::PROGRESSBAR:
+ case roles::BUTTONDROPDOWN:
+ case roles::BUTTONMENU:
+ case roles::CHECK_MENU_ITEM:
+ case roles::PASSWORD_TEXT:
+ case roles::RADIO_MENU_ITEM:
+ case roles::TOGGLE_BUTTON:
+ case roles::ENTRY:
+ case roles::KEY:
+ case roles::SLIDER:
+ case roles::SPINBUTTON:
+ case roles::OPTION:
+ case roles::SWITCH:
+ case roles::MATHML_MATH:
+ // Ignore the subtree, if there is one. So that we don't land on
+ // the same content that was already presented by its parent.
+ return nsIAccessibleTraversalRule::FILTER_MATCH |
+ nsIAccessibleTraversalRule::FILTER_IGNORE_SUBTREE;
+ default:
+ break;
+ }
+
+ return nsIAccessibleTraversalRule::FILTER_IGNORE;
+}