gecko/accessible/src/base/AccGroupInfo.cpp

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 * Contributor(s):
 *  Alexander Surkov <surkov.alexander@gmail.com> (original author)
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#include "AccGroupInfo.h"

#include "States.h"

using namespace mozilla::a11y;

AccGroupInfo::AccGroupInfo(nsAccessible* aItem, PRUint32 aRole) :
  mPosInSet(0), mSetSize(0), mParent(nsnull)
{
  MOZ_COUNT_CTOR(AccGroupInfo);
  nsAccessible* parent = aItem->Parent();
  if (!parent)
    return;

  PRInt32 indexInParent = aItem->IndexInParent();
  PRInt32 level = nsAccUtils::GetARIAOrDefaultLevel(aItem);

  // Compute position in set.
  mPosInSet = 1;
  for (PRInt32 idx = indexInParent - 1; idx >=0 ; idx--) {
    nsAccessible* sibling = parent->GetChildAt(idx);
    PRUint32 siblingRole = sibling->Role();

    // If the sibling is separator then the group is ended.
    if (siblingRole == nsIAccessibleRole::ROLE_SEPARATOR)
      break;

    // If sibling is not visible and hasn't the same base role.
    if (BaseRole(siblingRole) != aRole || 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).
    PRInt32 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;

  PRInt32 siblingCount = parent->GetChildCount();
  for (PRInt32 idx = indexInParent + 1; idx < siblingCount; idx++) {
    nsAccessible* sibling = parent->GetChildAt(idx);

    PRUint32 siblingRole = sibling->Role();

    // If the sibling is separator then the group is ended.
    if (siblingRole == nsIAccessibleRole::ROLE_SEPARATOR)
      break;

    // If sibling is visible and has the same base role
    if (BaseRole(siblingRole) != aRole || sibling->State() & states::INVISIBLE)
      continue;

    // and check if it's hierarchical flatten structure.
    PRInt32 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;

  // Compute parent.
  PRUint32 parentRole = parent->Role();

  // In the case of ARIA row in treegrid, return treegrid since ARIA
  // groups aren't used to organize levels in ARIA treegrids.
  if (aRole == nsIAccessibleRole::ROLE_ROW &&
      parentRole == nsIAccessibleRole::ROLE_TREE_TABLE) {
    mParent = parent;
    return;
  }

  // In the case of ARIA tree, a tree can be arranged by using ARIA groups
  // to organize levels. In this case the parent of the tree item will be
  // a group and the previous treeitem of that should be the tree item
  // parent. Or, if the parent is something other than a tree we will
  // return that.

  if (parentRole != nsIAccessibleRole::ROLE_GROUPING) {
    mParent = parent;
    return;
  }

  nsAccessible* parentPrevSibling = parent->PrevSibling();
  if (!parentPrevSibling)
    return;

  PRUint32 parentPrevSiblingRole = parentPrevSibling->Role();
  if (parentPrevSiblingRole == nsIAccessibleRole::ROLE_TEXT_LEAF) {
    // XXX Sometimes an empty text accessible is in the hierarchy here,
    // although the text does not appear to be rendered, GetRenderedText()
    // says that it is so we need to skip past it to find the true
    // previous sibling.
    parentPrevSibling = parentPrevSibling->PrevSibling();
    if (parentPrevSibling)
      parentPrevSiblingRole = parentPrevSibling->Role();
  }

  // Previous sibling of parent group is a tree item, this is the
  // conceptual tree item parent.
  if (parentPrevSiblingRole == nsIAccessibleRole::ROLE_OUTLINEITEM)
    mParent = parentPrevSibling;
}