C++ Accessible::PrevSibling方法代码示例

HyperTextAccessible*
nsAccessiblePivot::SearchForText(Accessible* aAccessible, bool aBackward)
{
  Accessible* root = GetActiveRoot();
  Accessible* accessible = aAccessible;
  while (true) {
    Accessible* child = nullptr;

    while ((child = (aBackward ? accessible->LastChild() :
                                 accessible->FirstChild()))) {
      accessible = child;
      if (child->IsHyperText())
        return child->AsHyperText();
    }

    Accessible* sibling = nullptr;
    Accessible* temp = accessible;
    do {
      if (temp == root)
        break;

      if (temp != aAccessible && temp->IsHyperText())
        return temp->AsHyperText();

      sibling = aBackward ? temp->PrevSibling() : temp->NextSibling();

      if (sibling)
        break;
    } while ((temp = temp->Parent()));

    if (!sibling)
      break;

    accessible = sibling;
    if (accessible->IsHyperText())
      return accessible->AsHyperText();
  }

  return nullptr;
}

//.........这里部分代码省略.........
      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->mBits.groupInfo) {
      mPosInSet += sibling->mBits.groupInfo->mPosInSet;
      mParent = sibling->mBits.groupInfo->mParent;
      mSetSize = sibling->mBits.groupInfo->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->mBits.groupInfo) {
      mParent = sibling->mBits.groupInfo->mParent;
      mSetSize = sibling->mBits.groupInfo->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;
  }
}