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/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
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 *
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 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is mozilla.org code.
 *
 * The Initial Developer of the Original Code is
 * Mozilla Foundation.
 * Portions created by the Initial Developer are Copyright (C) 2009
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Alexander Surkov <surkov.alexander@gmail.com> (original author)
 *
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 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
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 * ***** END LICENSE BLOCK ***** */

#include "nsRelUtils.h"

#include "nsAccessNode.h"

#include "nsIDOMDocument.h"
#include "nsIDOMElement.h"
#include "nsIDOMDocumentXBL.h"

#include "nsAutoPtr.h"
#include "nsArrayUtils.h"

already_AddRefed<nsIAccessible>
nsRelUtils::GetRelatedAccessible(nsIAccessible *aAccessible,
                                 PRUint32 aRelationType)
{
  nsCOMPtr<nsIAccessibleRelation> relation;
  nsresult rv = aAccessible->GetRelationByType(aRelationType,
                                               getter_AddRefs(relation));
  if (NS_FAILED(rv) || !relation)
    return nsnull;

  nsIAccessible *targetAccessible = nsnull;
  rv = relation->GetTarget(0, &targetAccessible);
  return targetAccessible;
}

nsresult
nsRelUtils::AddTarget(PRUint32 aRelationType, nsIAccessibleRelation **aRelation,
                      nsIAccessible *aTarget)
{
  if (!aTarget)
    return NS_OK_NO_RELATION_TARGET;

  if (*aRelation) {
    nsRefPtr<nsAccessibleRelation> relation = QueryAccRelation(*aRelation);
    return relation->AddTarget(aTarget);
  }

  *aRelation = new nsAccessibleRelationWrap(aRelationType, aTarget);
  NS_ENSURE_TRUE(*aRelation, NS_ERROR_OUT_OF_MEMORY);

  NS_ADDREF(*aRelation);
  return NS_OK;
}

nsresult
nsRelUtils::AddTargetFromContent(PRUint32 aRelationType,
                                 nsIAccessibleRelation **aRelation,
                                 nsIContent *aContent)
{
  if (!aContent)
    return NS_OK_NO_RELATION_TARGET;

  nsCOMPtr<nsIAccessibilityService> accService = nsAccessNode::GetAccService();
  nsCOMPtr<nsIDOMNode> node(do_QueryInterface(aContent));

  nsCOMPtr<nsIAccessible> accessible;
  accService->GetAccessibleFor(node, getter_AddRefs(accessible));
  return AddTarget(aRelationType, aRelation, accessible);
}

nsresult
nsRelUtils::AddTargetFromIDRefAttr(PRUint32 aRelationType,
                                   nsIAccessibleRelation **aRelation,
                                   nsIContent *aContent, nsIAtom *aAttr,
                                   PRBool aMayBeAnon)
{
  nsAutoString id;
  if (!aContent->GetAttr(kNameSpaceID_None, aAttr, id))
    return NS_OK_NO_RELATION_TARGET;

  nsCOMPtr<nsIDOMDocument> document =
    do_QueryInterface(aContent->GetOwnerDoc());
  NS_ASSERTION(document, "The given node is not in document!");
  if (!document)
    return NS_OK_NO_RELATION_TARGET;

  nsCOMPtr<nsIDOMElement> refElm;
  if (aMayBeAnon && aContent->GetBindingParent()) {
    nsCOMPtr<nsIDOMDocumentXBL> documentXBL(do_QueryInterface(document));
    nsCOMPtr<nsIDOMElement> bindingParent =
      do_QueryInterface(aContent->GetBindingParent());
    documentXBL->GetAnonymousElementByAttribute(bindingParent,
                                                NS_LITERAL_STRING("id"),
                                                id,
                                                getter_AddRefs(refElm));
  }
  else {
    document->GetElementById(id, getter_AddRefs(refElm));
  }

  nsCOMPtr<nsIContent> refContent(do_QueryInterface(refElm));
  return AddTargetFromContent(aRelationType, aRelation, refContent);
}

nsresult
nsRelUtils::AddTargetFromIDRefsAttr(PRUint32 aRelationType,
                                    nsIAccessibleRelation **aRelation,
                                    nsIContent *aContent, nsIAtom *aAttr)
{
  nsCOMPtr<nsIArray> refElms;
  nsCoreUtils::GetElementsByIDRefsAttr(aContent, aAttr, getter_AddRefs(refElms));

  if (!refElms)
    return NS_OK_NO_RELATION_TARGET;

  PRUint32 count = 0;
  nsresult rv = refElms->GetLength(&count);
  if (NS_FAILED(rv) || count == 0)
    return NS_OK_NO_RELATION_TARGET;

  nsCOMPtr<nsIContent> content;
  for (PRUint32 idx = 0; idx < count; idx++) {
    content = do_QueryElementAt(refElms, idx, &rv);
    NS_ENSURE_SUCCESS(rv, rv);

    rv = AddTargetFromContent(aRelationType, aRelation, content);
    NS_ENSURE_SUCCESS(rv, rv);
  }

  return NS_OK;
}

nsresult
nsRelUtils::AddTargetFromNeighbour(PRUint32 aRelationType,
                                   nsIAccessibleRelation **aRelation,
                                   nsIContent *aContent,
                                   nsIAtom *aNeighboutAttr,
                                   nsIAtom *aNeighboutTagName)
{
  return AddTargetFromContent(
    aRelationType, aRelation,
    nsCoreUtils::FindNeighbourPointingToNode(aContent, aNeighboutAttr,
                                             aNeighboutTagName));
}

nsresult
nsRelUtils::AddTargetFromChildrenHavingIDRefsAttr(PRUint32 aRelationType,
                                                  nsIAccessibleRelation **aRelation,
                                                  nsIContent *aRootContent,
                                                  nsIContent *aContent,
                                                  nsIAtom *aIDRefsAttr)
{
  nsCOMPtr<nsIArray> elms;
  nsCoreUtils::GetElementsHavingIDRefsAttr(aRootContent, aContent, aIDRefsAttr,
                                           getter_AddRefs(elms));
  if (!elms)
    return NS_OK_NO_RELATION_TARGET;

  PRUint32 count = 0;
  nsresult rv = elms->GetLength(&count);
  if (NS_FAILED(rv) || count == 0)
    return NS_OK_NO_RELATION_TARGET;

  nsCOMPtr<nsIContent> content;
  for (PRUint32 idx = 0; idx < count; idx++) {
    content = do_QueryElementAt(elms, idx, &rv);
    NS_ENSURE_SUCCESS(rv, rv);

    rv = AddTargetFromContent(aRelationType, aRelation, content);
    NS_ENSURE_SUCCESS(rv, rv);
  }

  return NS_OK;
}