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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
#include "AccessibleWrap.h"
#include "LocalAccessible-inl.h"
#include "AccAttributes.h"
#include "ApplicationAccessibleWrap.h"
#include "InterfaceInitFuncs.h"
#include "nsAccUtils.h"
#include "mozilla/a11y/PDocAccessible.h"
#include "OuterDocAccessible.h"
#include "RemoteAccessible.h"
#include "DocAccessibleParent.h"
#include "RootAccessible.h"
#include "mozilla/a11y/TableAccessible.h"
#include "mozilla/a11y/TableCellAccessible.h"
#include "nsMai.h"
#include "nsMaiHyperlink.h"
#include "nsString.h"
#include "nsStateMap.h"
#include "mozilla/a11y/Platform.h"
#include "Relation.h"
#include "RootAccessible.h"
#include "States.h"
#include "nsISimpleEnumerator.h"
#include "mozilla/ArrayUtils.h"
#include "mozilla/Sprintf.h"
#include "nsAccessibilityService.h"
#include "nsComponentManagerUtils.h"
using namespace mozilla;
using namespace mozilla::a11y;
MaiAtkObject::EAvailableAtkSignals MaiAtkObject::gAvailableAtkSignals =
eUnknown;
// defined in ApplicationAccessibleWrap.cpp
extern "C" GType g_atk_hyperlink_impl_type;
/* MaiAtkObject */
enum {
ACTIVATE,
CREATE,
DEACTIVATE,
DESTROY,
MAXIMIZE,
MINIMIZE,
RESIZE,
RESTORE,
LAST_SIGNAL
};
enum MaiInterfaceType {
MAI_INTERFACE_COMPONENT, /* 0 */
MAI_INTERFACE_ACTION,
MAI_INTERFACE_VALUE,
MAI_INTERFACE_EDITABLE_TEXT,
MAI_INTERFACE_HYPERTEXT,
MAI_INTERFACE_HYPERLINK_IMPL,
MAI_INTERFACE_SELECTION,
MAI_INTERFACE_TABLE,
MAI_INTERFACE_TEXT,
MAI_INTERFACE_DOCUMENT,
MAI_INTERFACE_IMAGE, /* 10 */
MAI_INTERFACE_TABLE_CELL
};
static GType GetAtkTypeForMai(MaiInterfaceType type) {
switch (type) {
case MAI_INTERFACE_COMPONENT:
return ATK_TYPE_COMPONENT;
case MAI_INTERFACE_ACTION:
return ATK_TYPE_ACTION;
case MAI_INTERFACE_VALUE:
return ATK_TYPE_VALUE;
case MAI_INTERFACE_EDITABLE_TEXT:
return ATK_TYPE_EDITABLE_TEXT;
case MAI_INTERFACE_HYPERTEXT:
return ATK_TYPE_HYPERTEXT;
case MAI_INTERFACE_HYPERLINK_IMPL:
return g_atk_hyperlink_impl_type;
case MAI_INTERFACE_SELECTION:
return ATK_TYPE_SELECTION;
case MAI_INTERFACE_TABLE:
return ATK_TYPE_TABLE;
case MAI_INTERFACE_TEXT:
return ATK_TYPE_TEXT;
case MAI_INTERFACE_DOCUMENT:
return ATK_TYPE_DOCUMENT;
case MAI_INTERFACE_IMAGE:
return ATK_TYPE_IMAGE;
case MAI_INTERFACE_TABLE_CELL:
MOZ_ASSERT(false);
}
return G_TYPE_INVALID;
}
#define NON_USER_EVENT ":system"
// The atk interfaces we can expose without checking what version of ATK we are
// dealing with. At the moment AtkTableCell is the only interface we can't
// always expose.
static const GInterfaceInfo atk_if_infos[] = {
{(GInterfaceInitFunc)componentInterfaceInitCB,
(GInterfaceFinalizeFunc) nullptr, nullptr},
{(GInterfaceInitFunc)actionInterfaceInitCB,
(GInterfaceFinalizeFunc) nullptr, nullptr},
{(GInterfaceInitFunc)valueInterfaceInitCB, (GInterfaceFinalizeFunc) nullptr,
nullptr},
{(GInterfaceInitFunc)editableTextInterfaceInitCB,
(GInterfaceFinalizeFunc) nullptr, nullptr},
{(GInterfaceInitFunc)hypertextInterfaceInitCB,
(GInterfaceFinalizeFunc) nullptr, nullptr},
{(GInterfaceInitFunc)hyperlinkImplInterfaceInitCB,
(GInterfaceFinalizeFunc) nullptr, nullptr},
{(GInterfaceInitFunc)selectionInterfaceInitCB,
(GInterfaceFinalizeFunc) nullptr, nullptr},
{(GInterfaceInitFunc)tableInterfaceInitCB, (GInterfaceFinalizeFunc) nullptr,
nullptr},
{(GInterfaceInitFunc)textInterfaceInitCB, (GInterfaceFinalizeFunc) nullptr,
nullptr},
{(GInterfaceInitFunc)documentInterfaceInitCB,
(GInterfaceFinalizeFunc) nullptr, nullptr},
{(GInterfaceInitFunc)imageInterfaceInitCB, (GInterfaceFinalizeFunc) nullptr,
nullptr}};
static GQuark quark_mai_hyperlink = 0;
AtkHyperlink* MaiAtkObject::GetAtkHyperlink() {
NS_ASSERTION(quark_mai_hyperlink, "quark_mai_hyperlink not initialized");
MaiHyperlink* maiHyperlink =
(MaiHyperlink*)g_object_get_qdata(G_OBJECT(this), quark_mai_hyperlink);
if (!maiHyperlink) {
maiHyperlink = new MaiHyperlink(acc);
g_object_set_qdata(G_OBJECT(this), quark_mai_hyperlink, maiHyperlink);
}
return maiHyperlink->GetAtkHyperlink();
}
void MaiAtkObject::Shutdown() {
acc = nullptr;
MaiHyperlink* maiHyperlink =
(MaiHyperlink*)g_object_get_qdata(G_OBJECT(this), quark_mai_hyperlink);
if (maiHyperlink) {
delete maiHyperlink;
g_object_set_qdata(G_OBJECT(this), quark_mai_hyperlink, nullptr);
}
}
struct MaiAtkObjectClass {
AtkObjectClass parent_class;
};
static guint mai_atk_object_signals[LAST_SIGNAL] = {
0,
};
static void MaybeFireNameChange(AtkObject* aAtkObj, const nsString& aNewName);
G_BEGIN_DECLS
/* callbacks for MaiAtkObject */
static void classInitCB(AtkObjectClass* aClass);
static void initializeCB(AtkObject* aAtkObj, gpointer aData);
static void finalizeCB(GObject* aObj);
/* callbacks for AtkObject virtual functions */
static const gchar* getNameCB(AtkObject* aAtkObj);
/* getDescriptionCB is also used by image interface */
const gchar* getDescriptionCB(AtkObject* aAtkObj);
static AtkRole getRoleCB(AtkObject* aAtkObj);
static AtkAttributeSet* getAttributesCB(AtkObject* aAtkObj);
static const gchar* GetLocaleCB(AtkObject*);
static AtkObject* getParentCB(AtkObject* aAtkObj);
static gint getChildCountCB(AtkObject* aAtkObj);
static AtkObject* refChildCB(AtkObject* aAtkObj, gint aChildIndex);
static gint getIndexInParentCB(AtkObject* aAtkObj);
static AtkStateSet* refStateSetCB(AtkObject* aAtkObj);
static AtkRelationSet* refRelationSetCB(AtkObject* aAtkObj);
/* the missing atkobject virtual functions */
/*
static AtkLayer getLayerCB(AtkObject *aAtkObj);
static gint getMdiZorderCB(AtkObject *aAtkObj);
static void SetNameCB(AtkObject *aAtkObj,
const gchar *name);
static void SetDescriptionCB(AtkObject *aAtkObj,
const gchar *description);
static void SetParentCB(AtkObject *aAtkObj,
AtkObject *parent);
static void SetRoleCB(AtkObject *aAtkObj,
AtkRole role);
static guint ConnectPropertyChangeHandlerCB(
AtkObject *aObj,
AtkPropertyChangeHandler *handler);
static void RemovePropertyChangeHandlerCB(
AtkObject *aAtkObj,
guint handler_id);
static void InitializeCB(AtkObject *aAtkObj,
gpointer data);
static void ChildrenChangedCB(AtkObject *aAtkObj,
guint change_index,
gpointer changed_child);
static void FocusEventCB(AtkObject *aAtkObj,
gboolean focus_in);
static void PropertyChangeCB(AtkObject *aAtkObj,
AtkPropertyValues *values);
static void StateChangeCB(AtkObject *aAtkObj,
const gchar *name,
gboolean state_set);
static void VisibleDataChangedCB(AtkObject *aAtkObj);
*/
G_END_DECLS
static GType GetMaiAtkType(uint16_t interfacesBits);
static const char* GetUniqueMaiAtkTypeName(uint16_t interfacesBits);
static gpointer parent_class = nullptr;
GType mai_atk_object_get_type(void) {
static GType type = 0;
if (!type) {
static const GTypeInfo tinfo = {
sizeof(MaiAtkObjectClass),
(GBaseInitFunc) nullptr,
(GBaseFinalizeFunc) nullptr,
(GClassInitFunc)classInitCB,
(GClassFinalizeFunc) nullptr,
nullptr, /* class data */
sizeof(MaiAtkObject), /* instance size */
0, /* nb preallocs */
(GInstanceInitFunc) nullptr,
nullptr /* value table */
};
type = g_type_register_static(ATK_TYPE_OBJECT, "MaiAtkObject", &tinfo,
GTypeFlags(0));
quark_mai_hyperlink = g_quark_from_static_string("MaiHyperlink");
}
return type;
}
AccessibleWrap::AccessibleWrap(nsIContent* aContent, DocAccessible* aDoc)
: LocalAccessible(aContent, aDoc), mAtkObject(nullptr) {}
AccessibleWrap::~AccessibleWrap() {
NS_ASSERTION(!mAtkObject, "ShutdownAtkObject() is not called");
}
void AccessibleWrap::ShutdownAtkObject() {
if (!mAtkObject) return;
NS_ASSERTION(IS_MAI_OBJECT(mAtkObject), "wrong type of atk object");
if (IS_MAI_OBJECT(mAtkObject)) MAI_ATK_OBJECT(mAtkObject)->Shutdown();
g_object_unref(mAtkObject);
mAtkObject = nullptr;
}
void AccessibleWrap::Shutdown() {
ShutdownAtkObject();
LocalAccessible::Shutdown();
}
void AccessibleWrap::GetNativeInterface(void** aOutAccessible) {
*aOutAccessible = nullptr;
if (!mAtkObject) {
if (IsDefunct() || IsText()) {
// We don't create ATK objects for node which has been shutdown or
// plain text leaves
return;
}
GType type = GetMaiAtkType(CreateMaiInterfaces());
if (!type) return;
mAtkObject = reinterpret_cast<AtkObject*>(g_object_new(type, nullptr));
if (!mAtkObject) return;
atk_object_initialize(mAtkObject, static_cast<Accessible*>(this));
mAtkObject->role = ATK_ROLE_INVALID;
mAtkObject->layer = ATK_LAYER_INVALID;
}
*aOutAccessible = mAtkObject;
}
AtkObject* AccessibleWrap::GetAtkObject(void) {
void* atkObj = nullptr;
GetNativeInterface(&atkObj);
return static_cast<AtkObject*>(atkObj);
}
// Get AtkObject from LocalAccessible interface
/* static */
AtkObject* AccessibleWrap::GetAtkObject(LocalAccessible* acc) {
void* atkObjPtr = nullptr;
acc->GetNativeInterface(&atkObjPtr);
return atkObjPtr ? ATK_OBJECT(atkObjPtr) : nullptr;
}
/* private */
uint16_t AccessibleWrap::CreateMaiInterfaces(void) {
uint16_t interfacesBits = 0;
// The Component interface is supported by all accessibles.
interfacesBits |= 1 << MAI_INTERFACE_COMPONENT;
// Add Action interface if the action count is more than zero.
if (ActionCount() > 0) interfacesBits |= 1 << MAI_INTERFACE_ACTION;
// Text, Editabletext, and Hypertext interface.
HyperTextAccessible* hyperText = AsHyperText();
if (hyperText && hyperText->IsTextRole()) {
interfacesBits |= 1 << MAI_INTERFACE_TEXT;
interfacesBits |= 1 << MAI_INTERFACE_EDITABLE_TEXT;
if (!nsAccUtils::MustPrune(this)) {
interfacesBits |= 1 << MAI_INTERFACE_HYPERTEXT;
}
}
// Value interface.
if (HasNumericValue()) interfacesBits |= 1 << MAI_INTERFACE_VALUE;
// Document interface.
if (IsDoc()) interfacesBits |= 1 << MAI_INTERFACE_DOCUMENT;
if (IsImage()) interfacesBits |= 1 << MAI_INTERFACE_IMAGE;
// HyperLink interface.
if (IsLink()) interfacesBits |= 1 << MAI_INTERFACE_HYPERLINK_IMPL;
if (!nsAccUtils::MustPrune(this)) { // These interfaces require children
// Table interface.
if (AsTable()) interfacesBits |= 1 << MAI_INTERFACE_TABLE;
if (AsTableCell()) interfacesBits |= 1 << MAI_INTERFACE_TABLE_CELL;
// Selection interface.
if (IsSelect()) {
interfacesBits |= 1 << MAI_INTERFACE_SELECTION;
}
}
return interfacesBits;
}
static GType GetMaiAtkType(uint16_t interfacesBits) {
GType type;
static const GTypeInfo tinfo = {
sizeof(MaiAtkObjectClass),
(GBaseInitFunc) nullptr,
(GBaseFinalizeFunc) nullptr,
(GClassInitFunc) nullptr,
(GClassFinalizeFunc) nullptr,
nullptr, /* class data */
sizeof(MaiAtkObject), /* instance size */
0, /* nb preallocs */
(GInstanceInitFunc) nullptr,
nullptr /* value table */
};
/*
* The members we use to register GTypes are GetAtkTypeForMai
* and atk_if_infos, which are constant values to each MaiInterface
* So we can reuse the registered GType when having
* the same MaiInterface types.
*/
const char* atkTypeName = GetUniqueMaiAtkTypeName(interfacesBits);
type = g_type_from_name(atkTypeName);
if (type) {
return type;
}
/*
* gobject limits the number of types that can directly derive from any
* given object type to 4095.
*/
static uint16_t typeRegCount = 0;
if (typeRegCount++ >= 4095) {
return G_TYPE_INVALID;
}
type = g_type_register_static(MAI_TYPE_ATK_OBJECT, atkTypeName, &tinfo,
GTypeFlags(0));
for (uint32_t index = 0; index < ArrayLength(atk_if_infos); index++) {
if (interfacesBits & (1 << index)) {
g_type_add_interface_static(type,
GetAtkTypeForMai((MaiInterfaceType)index),
&atk_if_infos[index]);
}
}
// Special case AtkTableCell so we can check what version of Atk we are
// dealing with.
if (IsAtkVersionAtLeast(2, 12) &&
(interfacesBits & (1 << MAI_INTERFACE_TABLE_CELL))) {
const GInterfaceInfo cellInfo = {
(GInterfaceInitFunc)tableCellInterfaceInitCB,
(GInterfaceFinalizeFunc) nullptr, nullptr};
g_type_add_interface_static(type, gAtkTableCellGetTypeFunc(), &cellInfo);
}
return type;
}
static const char* GetUniqueMaiAtkTypeName(uint16_t interfacesBits) {
#define MAI_ATK_TYPE_NAME_LEN (30) /* 10+sizeof(uint16_t)*8/4+1 < 30 */
static gchar namePrefix[] = "MaiAtkType"; /* size = 10 */
static gchar name[MAI_ATK_TYPE_NAME_LEN + 1];
SprintfLiteral(name, "%s%x", namePrefix, interfacesBits);
name[MAI_ATK_TYPE_NAME_LEN] = '\0';
return name;
}
bool AccessibleWrap::IsValidObject() {
// to ensure we are not shut down
return !IsDefunct();
}
/* static functions for ATK callbacks */
void classInitCB(AtkObjectClass* aClass) {
GObjectClass* gobject_class = G_OBJECT_CLASS(aClass);
parent_class = g_type_class_peek_parent(aClass);
aClass->get_name = getNameCB;
aClass->get_description = getDescriptionCB;
aClass->get_parent = getParentCB;
aClass->get_n_children = getChildCountCB;
aClass->ref_child = refChildCB;
aClass->get_index_in_parent = getIndexInParentCB;
aClass->get_role = getRoleCB;
aClass->get_attributes = getAttributesCB;
aClass->get_object_locale = GetLocaleCB;
aClass->ref_state_set = refStateSetCB;
aClass->ref_relation_set = refRelationSetCB;
aClass->initialize = initializeCB;
gobject_class->finalize = finalizeCB;
mai_atk_object_signals[ACTIVATE] = g_signal_new(
"activate", MAI_TYPE_ATK_OBJECT, G_SIGNAL_RUN_LAST,
0, /* default signal handler */
nullptr, nullptr, g_cclosure_marshal_VOID__VOID, G_TYPE_NONE, 0);
mai_atk_object_signals[CREATE] = g_signal_new(
"create", MAI_TYPE_ATK_OBJECT, G_SIGNAL_RUN_LAST,
0, /* default signal handler */
nullptr, nullptr, g_cclosure_marshal_VOID__VOID, G_TYPE_NONE, 0);
mai_atk_object_signals[DEACTIVATE] = g_signal_new(
"deactivate", MAI_TYPE_ATK_OBJECT, G_SIGNAL_RUN_LAST,
0, /* default signal handler */
nullptr, nullptr, g_cclosure_marshal_VOID__VOID, G_TYPE_NONE, 0);
mai_atk_object_signals[DESTROY] = g_signal_new(
"destroy", MAI_TYPE_ATK_OBJECT, G_SIGNAL_RUN_LAST,
0, /* default signal handler */
nullptr, nullptr, g_cclosure_marshal_VOID__VOID, G_TYPE_NONE, 0);
mai_atk_object_signals[MAXIMIZE] = g_signal_new(
"maximize", MAI_TYPE_ATK_OBJECT, G_SIGNAL_RUN_LAST,
0, /* default signal handler */
nullptr, nullptr, g_cclosure_marshal_VOID__VOID, G_TYPE_NONE, 0);
mai_atk_object_signals[MINIMIZE] = g_signal_new(
"minimize", MAI_TYPE_ATK_OBJECT, G_SIGNAL_RUN_LAST,
0, /* default signal handler */
nullptr, nullptr, g_cclosure_marshal_VOID__VOID, G_TYPE_NONE, 0);
mai_atk_object_signals[RESIZE] = g_signal_new(
"resize", MAI_TYPE_ATK_OBJECT, G_SIGNAL_RUN_LAST,
0, /* default signal handler */
nullptr, nullptr, g_cclosure_marshal_VOID__VOID, G_TYPE_NONE, 0);
mai_atk_object_signals[RESTORE] = g_signal_new(
"restore", MAI_TYPE_ATK_OBJECT, G_SIGNAL_RUN_LAST,
0, /* default signal handler */
nullptr, nullptr, g_cclosure_marshal_VOID__VOID, G_TYPE_NONE, 0);
}
void initializeCB(AtkObject* aAtkObj, gpointer aData) {
NS_ASSERTION((IS_MAI_OBJECT(aAtkObj)), "Invalid AtkObject");
NS_ASSERTION(aData, "Invalid Data to init AtkObject");
if (!aAtkObj || !aData) return;
/* call parent init function */
/* AtkObjectClass has not a "initialize" function now,
* maybe it has later
*/
if (ATK_OBJECT_CLASS(parent_class)->initialize) {
ATK_OBJECT_CLASS(parent_class)->initialize(aAtkObj, aData);
}
/* initialize object */
MAI_ATK_OBJECT(aAtkObj)->acc = static_cast<Accessible*>(aData);
}
void finalizeCB(GObject* aObj) {
if (!IS_MAI_OBJECT(aObj)) return;
NS_ASSERTION(!MAI_ATK_OBJECT(aObj)->acc, "acc NOT null");
// call parent finalize function
// finalize of GObjectClass will unref the accessible parent if has
if (G_OBJECT_CLASS(parent_class)->finalize) {
G_OBJECT_CLASS(parent_class)->finalize(aObj);
}
}
const gchar* getNameCB(AtkObject* aAtkObj) {
nsAutoString name;
if (Accessible* acc = GetInternalObj(aAtkObj)) {
acc->Name(name);
} else {
return nullptr;
}
// XXX Firing an event from here does not seem right
MaybeFireNameChange(aAtkObj, name);
return aAtkObj->name;
}
static void MaybeFireNameChange(AtkObject* aAtkObj, const nsString& aNewName) {
NS_ConvertUTF16toUTF8 newNameUTF8(aNewName);
if (aAtkObj->name && !strcmp(aAtkObj->name, newNameUTF8.get())) return;
// Below we duplicate the functionality of atk_object_set_name(),
// but without calling atk_object_get_name(). Instead of
// atk_object_get_name() we directly access aAtkObj->name. This is because
// atk_object_get_name() would call getNameCB() which would call
// MaybeFireNameChange() (or atk_object_set_name() before this problem was
// fixed) and we would get an infinite recursion.
// Do not notify for initial name setting.
bool notify = !!aAtkObj->name;
free(aAtkObj->name);
aAtkObj->name = strdup(newNameUTF8.get());
if (notify) g_object_notify(G_OBJECT(aAtkObj), "accessible-name");
}
const gchar* getDescriptionCB(AtkObject* aAtkObj) {
nsAutoString uniDesc;
if (Accessible* acc = GetInternalObj(aAtkObj)) {
acc->Description(uniDesc);
} else {
return nullptr;
}
NS_ConvertUTF8toUTF16 objDesc(aAtkObj->description);
if (!uniDesc.Equals(objDesc)) {
atk_object_set_description(aAtkObj, NS_ConvertUTF16toUTF8(uniDesc).get());
}
return aAtkObj->description;
}
AtkRole getRoleCB(AtkObject* aAtkObj) {
if (aAtkObj->role != ATK_ROLE_INVALID) return aAtkObj->role;
Accessible* acc = GetInternalObj(aAtkObj);
if (!acc) {
return ATK_ROLE_INVALID;
}
#ifdef DEBUG
if (AccessibleWrap* accWrap = GetAccessibleWrap(aAtkObj)) {
NS_ASSERTION(nsAccUtils::IsTextInterfaceSupportCorrect(accWrap),
"Does not support Text interface when it should");
}
#endif
#define ROLE(geckoRole, stringRole, ariaRole, atkRole, macRole, macSubrole, \
msaaRole, ia2Role, androidClass, iosIsElement, uiaControlType, \
nameRule) \
case roles::geckoRole: \
aAtkObj->role = atkRole; \
break;
switch (acc->Role()) {
#include "RoleMap.h"
default:
MOZ_CRASH("Unknown role.");
}
#undef ROLE
if (aAtkObj->role == ATK_ROLE_LIST_BOX && !IsAtkVersionAtLeast(2, 1)) {
aAtkObj->role = ATK_ROLE_LIST;
} else if (aAtkObj->role == ATK_ROLE_TABLE_ROW &&
!IsAtkVersionAtLeast(2, 1)) {
aAtkObj->role = ATK_ROLE_LIST_ITEM;
} else if (aAtkObj->role == ATK_ROLE_MATH && !IsAtkVersionAtLeast(2, 12)) {
aAtkObj->role = ATK_ROLE_SECTION;
} else if (aAtkObj->role == ATK_ROLE_COMMENT && !IsAtkVersionAtLeast(2, 12)) {
aAtkObj->role = ATK_ROLE_SECTION;
} else if (aAtkObj->role == ATK_ROLE_LANDMARK &&
!IsAtkVersionAtLeast(2, 12)) {
aAtkObj->role = ATK_ROLE_SECTION;
} else if (aAtkObj->role == ATK_ROLE_FOOTNOTE &&
!IsAtkVersionAtLeast(2, 25, 2)) {
aAtkObj->role = ATK_ROLE_SECTION;
} else if (aAtkObj->role == ATK_ROLE_STATIC && !IsAtkVersionAtLeast(2, 16)) {
aAtkObj->role = ATK_ROLE_TEXT;
} else if ((aAtkObj->role == ATK_ROLE_MATH_FRACTION ||
aAtkObj->role == ATK_ROLE_MATH_ROOT) &&
!IsAtkVersionAtLeast(2, 16)) {
aAtkObj->role = ATK_ROLE_SECTION;
} else if (aAtkObj->role == ATK_ROLE_MARK && !IsAtkVersionAtLeast(2, 36)) {
aAtkObj->role = ATK_ROLE_TEXT;
} else if (aAtkObj->role == ATK_ROLE_SUGGESTION &&
!IsAtkVersionAtLeast(2, 36)) {
aAtkObj->role = ATK_ROLE_SECTION;
} else if (aAtkObj->role == ATK_ROLE_COMMENT && !IsAtkVersionAtLeast(2, 36)) {
aAtkObj->role = ATK_ROLE_SECTION;
} else if ((aAtkObj->role == ATK_ROLE_CONTENT_DELETION ||
aAtkObj->role == ATK_ROLE_CONTENT_INSERTION) &&
!IsAtkVersionAtLeast(2, 34)) {
aAtkObj->role = ATK_ROLE_SECTION;
}
return aAtkObj->role;
}
static AtkAttributeSet* ConvertToAtkAttributeSet(AccAttributes* aAttributes) {
if (!aAttributes) {
return nullptr;
}
AtkAttributeSet* objAttributeSet = nullptr;
for (auto iter : *aAttributes) {
nsAutoString name;
iter.NameAsString(name);
if (name.Equals(u"placeholder")) {
name.AssignLiteral(u"placeholder-text");
}
nsAutoString value;
iter.ValueAsString(value);
AtkAttribute* objAttr = (AtkAttribute*)g_malloc(sizeof(AtkAttribute));
objAttr->name = g_strdup(NS_ConvertUTF16toUTF8(name).get());
objAttr->value = g_strdup(NS_ConvertUTF16toUTF8(value).get());
objAttributeSet = g_slist_prepend(objAttributeSet, objAttr);
}
// libspi will free it
return objAttributeSet;
}
AtkAttributeSet* getAttributesCB(AtkObject* aAtkObj) {
Accessible* acc = GetInternalObj(aAtkObj);
if (!acc) {
return nullptr;
}
RefPtr<AccAttributes> attributes = acc->Attributes();
return ConvertToAtkAttributeSet(attributes);
}
const gchar* GetLocaleCB(AtkObject* aAtkObj) {
Accessible* acc = GetInternalObj(aAtkObj);
if (!acc) {
return nullptr;
}
nsAutoString locale;
acc->Language(locale);
return AccessibleWrap::ReturnString(locale);
}
AtkObject* getParentCB(AtkObject* aAtkObj) {
if (aAtkObj->accessible_parent) return aAtkObj->accessible_parent;
Accessible* acc = GetInternalObj(aAtkObj);
if (!acc) {
return nullptr;
}
Accessible* parent = acc->Parent();
AtkObject* atkParent = parent ? GetWrapperFor(parent) : nullptr;
if (atkParent) atk_object_set_parent(aAtkObj, atkParent);
return aAtkObj->accessible_parent;
}
gint getChildCountCB(AtkObject* aAtkObj) {
Accessible* acc = GetInternalObj(aAtkObj);
if (!acc || nsAccUtils::MustPrune(acc)) {
return 0;
}
return static_cast<gint>(acc->EmbeddedChildCount());
}
AtkObject* refChildCB(AtkObject* aAtkObj, gint aChildIndex) {
// aChildIndex should not be less than zero
if (aChildIndex < 0) {
return nullptr;
}
Accessible* acc = GetInternalObj(aAtkObj);
if (!acc || nsAccUtils::MustPrune(acc)) {
return nullptr;
}
Accessible* accChild = acc->EmbeddedChildAt(aChildIndex);
if (!accChild) {
return nullptr;
}
AtkObject* childAtkObj = GetWrapperFor(accChild);
NS_ASSERTION(childAtkObj, "Fail to get AtkObj");
if (!childAtkObj) {
return nullptr;
}
g_object_ref(childAtkObj);
if (aAtkObj != childAtkObj->accessible_parent) {
atk_object_set_parent(childAtkObj, aAtkObj);
}
return childAtkObj;
}
gint getIndexInParentCB(AtkObject* aAtkObj) {
// We don't use LocalAccessible::IndexInParent() because we don't include text
// leaf nodes as children in ATK.
Accessible* acc = GetInternalObj(aAtkObj);
if (!acc) {
return -1;
}
if (acc->IsDoc()) {
return 0;
}
Accessible* parent = acc->Parent();
if (!parent) {
return -1;
}
return parent->IndexOfEmbeddedChild(acc);
}
static void TranslateStates(uint64_t aState, roles::Role aRole,
AtkStateSet* aStateSet) {
// atk doesn't have a read only state so read only things shouldn't be
// editable. However, we don't do this for list items because Gecko always
// exposes those as read only.
if ((aState & states::READONLY) && aRole != roles::LISTITEM) {
aState &= ~states::EDITABLE;
}
// Convert every state to an entry in AtkStateMap
uint64_t bitMask = 1;
for (auto stateIndex = 0U; stateIndex < gAtkStateMapLen; stateIndex++) {
if (gAtkStateMap[stateIndex]
.atkState) { // There's potentially an ATK state for this
bool isStateOn = (aState & bitMask) != 0;
if (gAtkStateMap[stateIndex].stateMapEntryType == kMapOpposite) {
isStateOn = !isStateOn;
}
if (isStateOn) {
atk_state_set_add_state(aStateSet, gAtkStateMap[stateIndex].atkState);
}
}
bitMask <<= 1;
}
}
AtkStateSet* refStateSetCB(AtkObject* aAtkObj) {
AtkStateSet* state_set = nullptr;
state_set = ATK_OBJECT_CLASS(parent_class)->ref_state_set(aAtkObj);
if (Accessible* acc = GetInternalObj(aAtkObj)) {
TranslateStates(acc->State(), acc->Role(), state_set);
} else {
TranslateStates(states::DEFUNCT, roles::NOTHING, state_set);
}
return state_set;
}
static void UpdateAtkRelation(RelationType aType, Accessible* aAcc,
AtkRelationType aAtkType,
AtkRelationSet* aAtkSet) {
if (aAtkType == ATK_RELATION_NULL) return;
AtkRelation* atkRelation =
atk_relation_set_get_relation_by_type(aAtkSet, aAtkType);
if (atkRelation) atk_relation_set_remove(aAtkSet, atkRelation);
Relation rel(aAcc->RelationByType(aType));
nsTArray<AtkObject*> targets;
Accessible* tempAcc = nullptr;
while ((tempAcc = rel.Next())) {
targets.AppendElement(GetWrapperFor(tempAcc));
}
if (targets.Length()) {
atkRelation =
atk_relation_new(targets.Elements(), targets.Length(), aAtkType);
atk_relation_set_add(aAtkSet, atkRelation);
g_object_unref(atkRelation);
}
}
AtkRelationSet* refRelationSetCB(AtkObject* aAtkObj) {
AtkRelationSet* relation_set =
ATK_OBJECT_CLASS(parent_class)->ref_relation_set(aAtkObj);
Accessible* acc = GetInternalObj(aAtkObj);
if (!acc) {
return relation_set;
}
#define RELATIONTYPE(geckoType, geckoTypeName, atkType, msaaType, ia2Type) \
UpdateAtkRelation(RelationType::geckoType, acc, atkType, relation_set);
#include "RelationTypeMap.h"
#undef RELATIONTYPE
return relation_set;
}
// Check if aAtkObj is a valid MaiAtkObject, and return the AccessibleWrap
// for it.
AccessibleWrap* GetAccessibleWrap(AtkObject* aAtkObj) {
NS_ENSURE_TRUE(IS_MAI_OBJECT(aAtkObj), nullptr);
// If we're working with an ATK object, we need to convert the Accessible
// back to an AccessibleWrap:
Accessible* storedAcc = MAI_ATK_OBJECT(aAtkObj)->acc;
if (!storedAcc) {
return nullptr;
}
auto* accWrap = static_cast<AccessibleWrap*>(storedAcc->AsLocal());
// Check if the accessible was deconstructed.
if (!accWrap) return nullptr;
NS_ENSURE_TRUE(accWrap->GetAtkObject() == aAtkObj, nullptr);
AccessibleWrap* appAccWrap = ApplicationAcc();
if (appAccWrap != accWrap && !accWrap->IsValidObject()) {
return nullptr;
}
return accWrap;
}
RemoteAccessible* GetProxy(AtkObject* aObj) {
Accessible* acc = GetInternalObj(aObj);
if (!acc) {
return nullptr;
}
return acc->AsRemote();
}
Accessible* GetInternalObj(AtkObject* aObj) {
if (!aObj || !IS_MAI_OBJECT(aObj)) return nullptr;
return MAI_ATK_OBJECT(aObj)->acc;
}
AtkObject* GetWrapperFor(Accessible* aAcc) {
if (!aAcc) {
return nullptr;
}
if (aAcc->IsRemote()) {
return reinterpret_cast<AtkObject*>(aAcc->AsRemote()->GetWrapper());
}
return AccessibleWrap::GetAtkObject(aAcc->AsLocal());
}
static uint16_t GetInterfacesForProxy(RemoteAccessible* aProxy) {
uint16_t interfaces = 1 << MAI_INTERFACE_COMPONENT;
if (aProxy->IsHyperText()) {
interfaces |= (1 << MAI_INTERFACE_HYPERTEXT) | (1 << MAI_INTERFACE_TEXT) |
(1 << MAI_INTERFACE_EDITABLE_TEXT);
}
if (aProxy->IsLink()) {
interfaces |= 1 << MAI_INTERFACE_HYPERLINK_IMPL;
}
if (aProxy->HasNumericValue()) {
interfaces |= 1 << MAI_INTERFACE_VALUE;
}
if (aProxy->IsTable()) {
interfaces |= 1 << MAI_INTERFACE_TABLE;
}
if (aProxy->IsTableCell()) {
interfaces |= 1 << MAI_INTERFACE_TABLE_CELL;
}
if (aProxy->IsImage()) {
interfaces |= 1 << MAI_INTERFACE_IMAGE;
}
if (aProxy->IsDoc()) {
interfaces |= 1 << MAI_INTERFACE_DOCUMENT;
}
if (aProxy->IsSelect()) {
interfaces |= 1 << MAI_INTERFACE_SELECTION;
}
if (aProxy->IsActionable()) {
interfaces |= 1 << MAI_INTERFACE_ACTION;
}
return interfaces;
}
void a11y::ProxyCreated(RemoteAccessible* aProxy) {
MOZ_ASSERT(aProxy->RemoteParent() || aProxy->IsDoc(),
"Need parent to check for HyperLink interface");
GType type = GetMaiAtkType(GetInterfacesForProxy(aProxy));
NS_ASSERTION(type, "why don't we have a type!");
AtkObject* obj = reinterpret_cast<AtkObject*>(g_object_new(type, nullptr));
if (!obj) return;
atk_object_initialize(obj, static_cast<Accessible*>(aProxy));
obj->role = ATK_ROLE_INVALID;
obj->layer = ATK_LAYER_INVALID;
aProxy->SetWrapper(reinterpret_cast<uintptr_t>(obj));
}
void a11y::ProxyDestroyed(RemoteAccessible* aProxy) {
auto obj = reinterpret_cast<MaiAtkObject*>(aProxy->GetWrapper());
if (!obj) {
return;
}
obj->Shutdown();
g_object_unref(obj);
aProxy->SetWrapper(0);
}
void a11y::PlatformEvent(Accessible* aTarget, uint32_t aEventType) {
AtkObject* wrapper = GetWrapperFor(aTarget);
switch (aEventType) {
case nsIAccessibleEvent::EVENT_DOCUMENT_LOAD_COMPLETE:
if (aTarget->IsDoc()) {
g_signal_emit_by_name(wrapper, "load_complete");
}
// XXX - Handle native dialog accessibles.
if (!aTarget->IsRoot() && aTarget->HasARIARole() &&
aTarget->Role() == roles::DIALOG) {
guint id = g_signal_lookup("activate", MAI_TYPE_ATK_OBJECT);
g_signal_emit(wrapper, id, 0);
}
break;
case nsIAccessibleEvent::EVENT_DOCUMENT_RELOAD:
if (aTarget->IsDoc()) {
g_signal_emit_by_name(wrapper, "reload");
}
break;
case nsIAccessibleEvent::EVENT_DOCUMENT_LOAD_STOPPED:
if (aTarget->IsDoc()) {
g_signal_emit_by_name(wrapper, "load_stopped");
}
break;
case nsIAccessibleEvent::EVENT_MENUPOPUP_START:
atk_focus_tracker_notify(wrapper); // fire extra focus event
atk_object_notify_state_change(wrapper, ATK_STATE_VISIBLE, true);
atk_object_notify_state_change(wrapper, ATK_STATE_SHOWING, true);
break;
case nsIAccessibleEvent::EVENT_MENUPOPUP_END:
atk_object_notify_state_change(wrapper, ATK_STATE_VISIBLE, false);
atk_object_notify_state_change(wrapper, ATK_STATE_SHOWING, false);
break;
case nsIAccessibleEvent::EVENT_ALERT:
// A hack using state change showing events as alert events.
atk_object_notify_state_change(wrapper, ATK_STATE_SHOWING, true);
break;
case nsIAccessibleEvent::EVENT_VALUE_CHANGE:
case nsIAccessibleEvent::EVENT_TEXT_VALUE_CHANGE:
if (aTarget->HasNumericValue()) {
// Make sure this is a numeric value. Don't fire for string value
// changes (e.g. text editing) ATK values are always numeric.
g_object_notify((GObject*)wrapper, "accessible-value");
}
break;
case nsIAccessibleEvent::EVENT_TEXT_SELECTION_CHANGED:
g_signal_emit_by_name(wrapper, "text_selection_changed");
break;
case nsIAccessibleEvent::EVENT_SELECTION_WITHIN:
g_signal_emit_by_name(wrapper, "selection_changed");
break;
case nsIAccessibleEvent::EVENT_TEXT_ATTRIBUTE_CHANGED:
g_signal_emit_by_name(wrapper, "text-attributes-changed");
break;
case nsIAccessibleEvent::EVENT_NAME_CHANGE: {
nsAutoString newName;
aTarget->Name(newName);
MaybeFireNameChange(wrapper, newName);
break;
}
case nsIAccessibleEvent::EVENT_WINDOW_ACTIVATE: {
guint id = g_signal_lookup("activate", MAI_TYPE_ATK_OBJECT);
g_signal_emit(wrapper, id, 0);
// Always fire a current focus event after activation.
FocusMgr()->ForceFocusEvent();
break;
}
case nsIAccessibleEvent::EVENT_WINDOW_DEACTIVATE: {
guint id = g_signal_lookup("deactivate", MAI_TYPE_ATK_OBJECT);
g_signal_emit(wrapper, id, 0);
break;
}
case nsIAccessibleEvent::EVENT_WINDOW_MAXIMIZE: {
guint id = g_signal_lookup("maximize", MAI_TYPE_ATK_OBJECT);
g_signal_emit(wrapper, id, 0);
break;
}
case nsIAccessibleEvent::EVENT_WINDOW_MINIMIZE: {
guint id = g_signal_lookup("minimize", MAI_TYPE_ATK_OBJECT);
g_signal_emit(wrapper, id, 0);
break;
}
case nsIAccessibleEvent::EVENT_WINDOW_RESTORE: {
guint id = g_signal_lookup("restore", MAI_TYPE_ATK_OBJECT);
g_signal_emit(wrapper, id, 0);
break;
}
}
}
void a11y::PlatformStateChangeEvent(Accessible* aTarget, uint64_t aState,
bool aEnabled) {
MaiAtkObject* atkObj = MAI_ATK_OBJECT(GetWrapperFor(aTarget));
atkObj->FireStateChangeEvent(aState, aEnabled);
}
void a11y::PlatformFocusEvent(Accessible* aTarget,
const LayoutDeviceIntRect& aCaretRect) {
AtkObject* wrapper = GetWrapperFor(aTarget);
// XXX Do we really need this check? If so, do we need a similar check for
// RemoteAccessible?
if (LocalAccessible* localTarget = aTarget->AsLocal()) {
a11y::RootAccessible* rootAcc = localTarget->RootAccessible();
if (!rootAcc || !rootAcc->IsActivated()) {
return;
}
}
atk_focus_tracker_notify(wrapper);
atk_object_notify_state_change(wrapper, ATK_STATE_FOCUSED, true);
}
void a11y::PlatformCaretMoveEvent(Accessible* aTarget, int32_t aOffset,
bool aIsSelectionCollapsed,
int32_t aGranularity,
const LayoutDeviceIntRect& aCaretRect,
bool aFromUser) {
AtkObject* wrapper = GetWrapperFor(aTarget);
g_signal_emit_by_name(wrapper, "text_caret_moved", aOffset);
}
void MaiAtkObject::FireStateChangeEvent(uint64_t aState, bool aEnabled) {
auto state = aState;
int32_t stateIndex = -1;
while (state > 0) {
++stateIndex;
state >>= 1;
}
MOZ_ASSERT(
stateIndex >= 0 && stateIndex < static_cast<int32_t>(gAtkStateMapLen),
"No ATK state for internal state was found");
if (stateIndex < 0 || stateIndex >= static_cast<int32_t>(gAtkStateMapLen)) {
return;
}
if (gAtkStateMap[stateIndex].atkState != kNone) {
MOZ_ASSERT(gAtkStateMap[stateIndex].stateMapEntryType != kNoStateChange,
"State changes should not fired for this state");
if (gAtkStateMap[stateIndex].stateMapEntryType == kMapOpposite) {
aEnabled = !aEnabled;
}
// Fire state change for first state if there is one to map
atk_object_notify_state_change(&parent, gAtkStateMap[stateIndex].atkState,
aEnabled);
}
}
void a11y::PlatformTextChangeEvent(Accessible* aTarget, const nsAString& aStr,
int32_t aStart, uint32_t aLen,
bool aIsInsert, bool aFromUser) {
MaiAtkObject* atkObj = MAI_ATK_OBJECT(GetWrapperFor(aTarget));
atkObj->FireTextChangeEvent(aStr, aStart, aLen, aIsInsert, aFromUser);
}
#define OLD_TEXT_INSERTED "text_changed::insert"
#define OLD_TEXT_REMOVED "text_changed::delete"
static const char* oldTextChangeStrings[2][2] = {
{OLD_TEXT_REMOVED NON_USER_EVENT, OLD_TEXT_INSERTED NON_USER_EVENT},
{OLD_TEXT_REMOVED, OLD_TEXT_INSERTED}};
#define TEXT_INSERTED "text-insert"
#define TEXT_REMOVED "text-remove"
#define NON_USER_DETAIL "::system"
static const char* textChangedStrings[2][2] = {
{TEXT_REMOVED NON_USER_DETAIL, TEXT_INSERTED NON_USER_DETAIL},
{TEXT_REMOVED, TEXT_INSERTED}};
void MaiAtkObject::FireTextChangeEvent(const nsAString& aStr, int32_t aStart,
uint32_t aLen, bool aIsInsert,
bool aFromUser) {
if (gAvailableAtkSignals == eUnknown) {
gAvailableAtkSignals = g_signal_lookup("text-insert", G_OBJECT_TYPE(this))
? eHaveNewAtkTextSignals
: eNoNewAtkSignals;
}
if (gAvailableAtkSignals == eNoNewAtkSignals) {
// XXX remove this code and the gHaveNewTextSignals check when we can
// stop supporting old atk since it doesn't really work anyway
const char* signal_name = oldTextChangeStrings[aFromUser][aIsInsert];
g_signal_emit_by_name(this, signal_name, aStart, aLen);
} else {
const char* signal_name = textChangedStrings[aFromUser][aIsInsert];
g_signal_emit_by_name(this, signal_name, aStart, aLen,
NS_ConvertUTF16toUTF8(aStr).get());
}
}
void a11y::PlatformShowHideEvent(Accessible* aTarget, Accessible* aParent,
bool aInsert, bool aFromUser) {
AtkObject* atkObj = GetWrapperFor(aTarget);
if (!aInsert) {
// XXX - Handle native dialog accessibles.
if (!aTarget->IsRoot() && aTarget->HasARIARole() &&
aTarget->Role() == roles::DIALOG) {
guint id = g_signal_lookup("deactivate", MAI_TYPE_ATK_OBJECT);
g_signal_emit(atkObj, id, 0);
}
}
MaiAtkObject* obj = MAI_ATK_OBJECT(atkObj);
obj->FireAtkShowHideEvent(GetWrapperFor(aParent), aInsert, aFromUser);
}
#define ADD_EVENT "children_changed::add"
#define HIDE_EVENT "children_changed::remove"
static const char* kMutationStrings[2][2] = {
{HIDE_EVENT NON_USER_EVENT, ADD_EVENT NON_USER_EVENT},
{HIDE_EVENT, ADD_EVENT},
};
void MaiAtkObject::FireAtkShowHideEvent(AtkObject* aParent, bool aIsAdded,
bool aFromUser) {
if (!aParent) {
// XXX ATK needs a parent for these events. However, we might have already
// unbound from the parent by the time we fire a hide event. Ideally, we
// need to find a way to keep the parent around, but ATK clients don't seem
// to care about these missing events.
MOZ_ASSERT(!aIsAdded);
return;
}
int32_t indexInParent = getIndexInParentCB(&this->parent);
const char* signal_name = kMutationStrings[aFromUser][aIsAdded];
g_signal_emit_by_name(aParent, signal_name, indexInParent, this, nullptr);
}
void a11y::PlatformSelectionEvent(Accessible*, Accessible* aWidget, uint32_t) {
MaiAtkObject* obj = MAI_ATK_OBJECT(GetWrapperFor(aWidget));
g_signal_emit_by_name(obj, "selection_changed");
}
// static
void AccessibleWrap::GetKeyBinding(Accessible* aAccessible,
nsAString& aResult) {
// Return all key bindings including access key and keyboard shortcut.
// Get access key.
nsAutoString keyBindingsStr;
KeyBinding keyBinding = aAccessible->AccessKey();
if (!keyBinding.IsEmpty()) {
keyBinding.AppendToString(keyBindingsStr, KeyBinding::eAtkFormat);
Accessible* parent = aAccessible->Parent();
roles::Role role = parent ? parent->Role() : roles::NOTHING;
if (role == roles::PARENT_MENUITEM || role == roles::MENUITEM ||
role == roles::RADIO_MENU_ITEM || role == roles::CHECK_MENU_ITEM) {
// It is submenu, expose keyboard shortcuts from menu hierarchy like
// "s;<Alt>f:s"
nsAutoString keysInHierarchyStr = keyBindingsStr;
do {
KeyBinding parentKeyBinding = parent->AccessKey();
if (!parentKeyBinding.IsEmpty()) {
nsAutoString str;
parentKeyBinding.ToString(str, KeyBinding::eAtkFormat);
str.Append(':');
keysInHierarchyStr.Insert(str, 0);
}
} while ((parent = parent->Parent()) && parent->Role() != roles::MENUBAR);
keyBindingsStr.Append(';');
keyBindingsStr.Append(keysInHierarchyStr);
}
} else {
// No access key, add ';' to point this.
keyBindingsStr.Append(';');
}
// Get keyboard shortcut.
keyBindingsStr.Append(';');
if (LocalAccessible* localAcc = aAccessible->AsLocal()) {
keyBinding = localAcc->KeyboardShortcut();
if (!keyBinding.IsEmpty()) {
keyBinding.AppendToString(keyBindingsStr, KeyBinding::eAtkFormat);
}
}
aResult = keyBindingsStr;
}
// static
Accessible* AccessibleWrap::GetColumnHeader(TableAccessible* aAccessible,
int32_t aColIdx) {
if (!aAccessible) {
return nullptr;
}
Accessible* cell = aAccessible->CellAt(0, aColIdx);
if (!cell) {
return nullptr;
}
// If the cell at the first row is column header then assume it is column
// header for all rows,
if (cell->Role() == roles::COLUMNHEADER) {
return cell;
}
// otherwise get column header for the data cell at the first row.
TableCellAccessible* tableCell = cell->AsTableCell();
if (!tableCell) {
return nullptr;
}
AutoTArray<Accessible*, 10> headerCells;
tableCell->ColHeaderCells(&headerCells);
if (headerCells.IsEmpty()) {
return nullptr;
}
return headerCells[0];
}
// static
Accessible* AccessibleWrap::GetRowHeader(TableAccessible* aAccessible,
int32_t aRowIdx) {
if (!aAccessible) {
return nullptr;
}
Accessible* cell = aAccessible->CellAt(aRowIdx, 0);
if (!cell) {
return nullptr;
}
// If the cell at the first column is row header then assume it is row
// header for all columns,
if (cell->Role() == roles::ROWHEADER) {
return cell;
}
// otherwise get row header for the data cell at the first column.
TableCellAccessible* tableCell = cell->AsTableCell();
if (!tableCell) {
return nullptr;
}
AutoTArray<Accessible*, 10> headerCells;
tableCell->RowHeaderCells(&headerCells);
if (headerCells.IsEmpty()) {
return nullptr;
}
return headerCells[0];
}