gecko-dev/accessible/src/html/nsHTMLLinkAccessible.cpp

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 * The Original Code is mozilla.org code.
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 * Contributor(s):
 *   Aaron Leventhal <aleventh@us.ibm.com> (original author)
 *   Alexander Surkov <surkov.alexander@gmail.com>
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#include "nsHTMLLinkAccessible.h"

#include "nsCoreUtils.h"

#include "nsILink.h"

////////////////////////////////////////////////////////////////////////////////
// nsHTMLLinkAccessible

nsHTMLLinkAccessible::nsHTMLLinkAccessible(nsIDOMNode* aDomNode,
                                           nsIWeakReference* aShell):
  nsHyperTextAccessibleWrap(aDomNode, aShell)
{ 
}

// Expose nsIAccessibleHyperLink unconditionally
NS_IMPL_ISUPPORTS_INHERITED1(nsHTMLLinkAccessible, nsHyperTextAccessibleWrap,
                             nsIAccessibleHyperLink)

////////////////////////////////////////////////////////////////////////////////
// nsIAccessible

nsresult
nsHTMLLinkAccessible::GetRoleInternal(PRUint32 *aRole)
{
  *aRole = nsIAccessibleRole::ROLE_LINK;
  return NS_OK;
}

nsresult
nsHTMLLinkAccessible::GetStateInternal(PRUint32 *aState, PRUint32 *aExtraState)
{
  nsresult rv = nsHyperTextAccessibleWrap::GetStateInternal(aState,
                                                            aExtraState);
  NS_ENSURE_A11Y_SUCCESS(rv, rv);

  *aState  &= ~nsIAccessibleStates::STATE_READONLY;

  nsCOMPtr<nsIContent> content(do_QueryInterface(mDOMNode));
  if (content && content->HasAttr(kNameSpaceID_None,
                                  nsAccessibilityAtoms::name)) {
    // This is how we indicate it is a named anchor
    // In other words, this anchor can be selected as a location :)
    // There is no other better state to use to indicate this.
    *aState |= nsIAccessibleStates::STATE_SELECTABLE;
  }

  nsLinkState linkState = content->GetLinkState();
  if (linkState == eLinkState_NotLink || linkState == eLinkState_Unknown) {
    // This is a either named anchor (a link with also a name attribute) or
    // it doesn't have any attributes. Check if 'click' event handler is
    // registered, otherwise bail out.
    PRBool isOnclick = nsCoreUtils::HasClickListener(content);
    if (!isOnclick)
      return NS_OK;
  }

  *aState |= nsIAccessibleStates::STATE_LINKED;

  if (linkState == eLinkState_Visited)
    *aState |= nsIAccessibleStates::STATE_TRAVERSED;

  return NS_OK;
}

NS_IMETHODIMP
nsHTMLLinkAccessible::GetValue(nsAString& aValue)
{
  aValue.Truncate();

  nsresult rv = nsHyperTextAccessible::GetValue(aValue);
  NS_ENSURE_SUCCESS(rv, rv);

  if (!aValue.IsEmpty())
    return NS_OK;
  
  nsCOMPtr<nsIPresShell> presShell(do_QueryReferent(mWeakShell));
  if (mDOMNode && presShell)
    return presShell->GetLinkLocation(mDOMNode, aValue);

  return NS_OK;
}

NS_IMETHODIMP
nsHTMLLinkAccessible::GetNumActions(PRUint8 *aNumActions)
{
  NS_ENSURE_ARG_POINTER(aNumActions);

  if (!IsLinked())
    return nsHyperTextAccessible::GetNumActions(aNumActions);

  *aNumActions = 1;
  return NS_OK;
}

NS_IMETHODIMP
nsHTMLLinkAccessible::GetActionName(PRUint8 aIndex, nsAString& aName)
{
  aName.Truncate();

  if (!IsLinked())
    return nsHyperTextAccessible::GetActionName(aIndex, aName);

  // Action 0 (default action): Jump to link
  if (aIndex != eAction_Jump)
    return NS_ERROR_INVALID_ARG;

  aName.AssignLiteral("jump");
  return NS_OK;
}

NS_IMETHODIMP
nsHTMLLinkAccessible::DoAction(PRUint8 aIndex)
{
  if (!IsLinked())
    return nsHyperTextAccessible::DoAction(aIndex);

  // Action 0 (default action): Jump to link
  if (aIndex != eAction_Jump)
    return NS_ERROR_INVALID_ARG;

  if (IsDefunct())
    return NS_ERROR_FAILURE;

  DoCommand();
  return NS_OK;
}

////////////////////////////////////////////////////////////////////////////////
// nsIAccessibleHyperLink

NS_IMETHODIMP
nsHTMLLinkAccessible::GetURI(PRInt32 aIndex, nsIURI **aURI)
{
  NS_ENSURE_ARG_POINTER(aURI);
  *aURI = nsnull;

  if (aIndex != 0)
    return NS_ERROR_INVALID_ARG;

  nsCOMPtr<nsIContent> link(do_QueryInterface(mDOMNode));
  NS_ENSURE_STATE(link);

  *aURI = link->GetHrefURI().get();
  return NS_OK;
}

////////////////////////////////////////////////////////////////////////////////
// Protected members

PRBool
nsHTMLLinkAccessible::IsLinked()
{
  nsCOMPtr<nsIContent> link(do_QueryInterface(mDOMNode));
  if (!link)
    return PR_FALSE;

  nsLinkState linkState = link->GetLinkState();

  return linkState != eLinkState_NotLink && linkState != eLinkState_Unknown;
}