gecko-dev/accessible/base/AccGroupInfo.cpp

228 строки
6.9 KiB
C++

/* 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 "AccGroupInfo.h"
#include "nsAccUtils.h"
#include "Role.h"
#include "States.h"
using namespace mozilla::a11y;
AccGroupInfo::AccGroupInfo(Accessible* aItem, role aRole) :
mPosInSet(0), mSetSize(0), mParent(nullptr), mItem(aItem), mRole(aRole)
{
MOZ_COUNT_CTOR(AccGroupInfo);
Update();
}
void
AccGroupInfo::Update()
{
Accessible* parent = mItem->Parent();
if (!parent)
return;
int32_t indexInParent = mItem->IndexInParent();
uint32_t siblingCount = parent->ChildCount();
if (indexInParent == -1 ||
indexInParent >= static_cast<int32_t>(siblingCount)) {
NS_ERROR("Wrong index in parent! Tree invalidation problem.");
return;
}
int32_t level = nsAccUtils::GetARIAOrDefaultLevel(mItem);
// Compute position in set.
mPosInSet = 1;
for (int32_t idx = indexInParent - 1; idx >= 0 ; idx--) {
Accessible* sibling = parent->GetChildAt(idx);
roles::Role siblingRole = sibling->Role();
// If the sibling is separator then the group is ended.
if (siblingRole == roles::SEPARATOR)
break;
// If sibling is not visible and hasn't the same base role.
if (BaseRole(siblingRole) != mRole || sibling->State() & states::INVISIBLE)
continue;
// Check if it's hierarchical flatten structure, i.e. if the sibling
// level is lesser than this one then group is ended, if the sibling level
// is greater than this one then the group is split by some child elements
// (group will be continued).
int32_t siblingLevel = nsAccUtils::GetARIAOrDefaultLevel(sibling);
if (siblingLevel < level) {
mParent = sibling;
break;
}
// Skip subset.
if (siblingLevel > level)
continue;
// If the previous item in the group has calculated group information then
// build group information for this item based on found one.
if (sibling->mGroupInfo) {
mPosInSet += sibling->mGroupInfo->mPosInSet;
mParent = sibling->mGroupInfo->mParent;
mSetSize = sibling->mGroupInfo->mSetSize;
return;
}
mPosInSet++;
}
// Compute set size.
mSetSize = mPosInSet;
for (uint32_t idx = indexInParent + 1; idx < siblingCount; idx++) {
Accessible* sibling = parent->GetChildAt(idx);
roles::Role siblingRole = sibling->Role();
// If the sibling is separator then the group is ended.
if (siblingRole == roles::SEPARATOR)
break;
// If sibling is visible and has the same base role
if (BaseRole(siblingRole) != mRole || sibling->State() & states::INVISIBLE)
continue;
// and check if it's hierarchical flatten structure.
int32_t siblingLevel = nsAccUtils::GetARIAOrDefaultLevel(sibling);
if (siblingLevel < level)
break;
// Skip subset.
if (siblingLevel > level)
continue;
// If the next item in the group has calculated group information then
// build group information for this item based on found one.
if (sibling->mGroupInfo) {
mParent = sibling->mGroupInfo->mParent;
mSetSize = sibling->mGroupInfo->mSetSize;
return;
}
mSetSize++;
}
if (mParent)
return;
roles::Role parentRole = parent->Role();
if (ShouldReportRelations(mRole, parentRole))
mParent = parent;
// ARIA tree and list can be arranged by using ARIA groups to organize levels.
if (parentRole != roles::GROUPING)
return;
// Way #1 for ARIA tree (not ARIA treegrid): previous sibling of a group is a
// parent. In other words the parent of the tree item will be a group and
// the previous tree item of the group is a conceptual parent of the tree
// item.
if (mRole == roles::OUTLINEITEM) {
Accessible* parentPrevSibling = parent->PrevSibling();
if (parentPrevSibling && parentPrevSibling->Role() == mRole) {
mParent = parentPrevSibling;
return;
}
}
// Way #2 for ARIA list and tree: group is a child of an item. In other words
// the parent of the item will be a group and containing item of the group is
// a conceptual parent of the item.
if (mRole == roles::LISTITEM || mRole == roles::OUTLINEITEM) {
Accessible* grandParent = parent->Parent();
if (grandParent && grandParent->Role() == mRole)
mParent = grandParent;
}
}
Accessible*
AccGroupInfo::FirstItemOf(Accessible* aContainer)
{
// ARIA tree can be arranged by ARIA groups case #1 (previous sibling of a
// group is a parent) or by aria-level.
a11y::role containerRole = aContainer->Role();
Accessible* item = aContainer->NextSibling();
if (item) {
if (containerRole == roles::OUTLINEITEM && item->Role() == roles::GROUPING)
item = item->FirstChild();
if (item) {
AccGroupInfo* itemGroupInfo = item->GetGroupInfo();
if (itemGroupInfo && itemGroupInfo->ConceptualParent() == aContainer)
return item;
}
}
// ARIA list and tree can be arranged by ARIA groups case #2 (group is
// a child of an item).
item = aContainer->LastChild();
if (!item)
return nullptr;
if (item->Role() == roles::GROUPING &&
(containerRole == roles::LISTITEM || containerRole == roles::OUTLINEITEM)) {
item = item->FirstChild();
if (item) {
AccGroupInfo* itemGroupInfo = item->GetGroupInfo();
if (itemGroupInfo && itemGroupInfo->ConceptualParent() == aContainer)
return item;
}
}
// Otherwise, it can be a direct child if the container is a list or tree.
item = aContainer->FirstChild();
if (ShouldReportRelations(item->Role(), containerRole))
return item;
return nullptr;
}
Accessible*
AccGroupInfo::NextItemTo(Accessible* aItem)
{
AccGroupInfo* groupInfo = aItem->GetGroupInfo();
if (!groupInfo)
return nullptr;
// If the item in middle of the group then search next item in siblings.
if (groupInfo->PosInSet() >= groupInfo->SetSize())
return nullptr;
Accessible* parent = aItem->Parent();
uint32_t childCount = parent->ChildCount();
for (uint32_t idx = aItem->IndexInParent() + 1; idx < childCount; idx++) {
Accessible* nextItem = parent->GetChildAt(idx);
AccGroupInfo* nextGroupInfo = nextItem->GetGroupInfo();
if (nextGroupInfo &&
nextGroupInfo->ConceptualParent() == groupInfo->ConceptualParent()) {
return nextItem;
}
}
NS_NOTREACHED("Item in the middle of the group but there's no next item!");
return nullptr;
}
bool
AccGroupInfo::ShouldReportRelations(role aRole, role aParentRole)
{
// We only want to report hierarchy-based node relations for items in tree or
// list form. ARIA level/owns relations are always reported.
if (aParentRole == roles::OUTLINE && aRole == roles::OUTLINEITEM)
return true;
if (aParentRole == roles::TREE_TABLE && aRole == roles::ROW)
return true;
if (aParentRole == roles::LIST && aRole == roles::LISTITEM)
return true;
return false;
}