gecko-dev/accessible/src/base/nsBaseWidgetAccessible.cpp

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 * for the specific language governing rights and limitations under the
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 * The Original Code is mozilla.org code.
 *
 * The Initial Developer of the Original Code is
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 * Portions created by the Initial Developer are Copyright (C) 1998
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   John Gaunt (jgaunt@netscape.com)
 *
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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"),
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#include "nsBaseWidgetAccessible.h"
#include "nsAccessibilityAtoms.h"
#include "nsIAccessibilityService.h"
#include "nsIAccessibleDocument.h"
#include "nsAccessibleWrap.h"
#include "nsGUIEvent.h"
#include "nsHyperTextAccessible.h"
#include "nsILink.h"
#include "nsIFrame.h"
#include "nsINameSpaceManager.h"
#include "nsPresContext.h"
#include "nsIPresShell.h"
#include "nsIServiceManager.h"
#include "nsIURI.h"

//-------------
// nsLeafAccessible
//-------------

nsLeafAccessible::nsLeafAccessible(nsIDOMNode* aNode, nsIWeakReference* aShell):
nsAccessibleWrap(aNode, aShell)
{
}

NS_IMPL_ISUPPORTS_INHERITED0(nsLeafAccessible, nsAccessible)

/* nsIAccessible getFirstChild (); */
NS_IMETHODIMP nsLeafAccessible::GetFirstChild(nsIAccessible **_retval)
{
  *_retval = nsnull;
  return NS_OK;
}

/* nsIAccessible getLastChild (); */
NS_IMETHODIMP nsLeafAccessible::GetLastChild(nsIAccessible **_retval)
{
  *_retval = nsnull;
  return NS_OK;
}

/* long getAccChildCount (); */
NS_IMETHODIMP nsLeafAccessible::GetChildCount(PRInt32 *_retval)
{
  *_retval = 0;
  return NS_OK;
}

/* readonly attribute boolean allowsAnonChildAccessibles; */
NS_IMETHODIMP
nsLeafAccessible::GetAllowsAnonChildAccessibles(PRBool *aAllowsAnonChildren)
{
  *aAllowsAnonChildren = PR_FALSE;
  return NS_OK;
}

//----------------
// nsLinkableAccessible
//----------------

nsLinkableAccessible::nsLinkableAccessible(nsIDOMNode* aNode, nsIWeakReference* aShell) :
  nsHyperTextAccessible(aNode, aShell),
  mActionContent(nsnull),
  mIsLink(PR_FALSE),
  mIsOnclick(PR_FALSE)
{
}

NS_IMPL_ISUPPORTS_INHERITED0(nsLinkableAccessible, nsHyperTextAccessible)

NS_IMETHODIMP nsLinkableAccessible::TakeFocus()
{ 
  if (mActionContent && mActionContent->IsFocusable()) {
    mActionContent->SetFocus(nsCOMPtr<nsPresContext>(GetPresContext()));
  }
  
  return NS_OK;
}

/* long GetState (); */
NS_IMETHODIMP nsLinkableAccessible::GetState(PRUint32 *aState)
{
  nsHyperTextAccessible::GetState(aState);
  if (mIsLink) {
    *aState |= STATE_LINKED;
    nsCOMPtr<nsILink> link = do_QueryInterface(mActionContent);
    if (link) {
      nsLinkState linkState;
      link->GetLinkState(linkState);
      if (linkState == eLinkState_Visited) {
        *aState |= STATE_TRAVERSED;
      }
    }
    // Make sure we also include all the states of the parent link, such as focusable, focused, etc.
    PRUint32 role;
    GetRole(&role);
    if (role != ROLE_LINK) {
      nsCOMPtr<nsIAccessible> parentAccessible(GetParent());
      if (parentAccessible) {
        PRUint32 orState = 0;
        parentAccessible->GetFinalState(&orState);
        *aState |= orState;
      }
    }
  }
  if (mActionContent && !mActionContent->IsFocusable()) {
    *aState &= ~STATE_FOCUSABLE; // Links must have href or tabindex
  }

  // XXX What if we're in a contenteditable container?
  //     We may need to go up the parent chain unless a better API is found
  nsCOMPtr<nsIAccessible> docAccessible = 
    do_QueryInterface(nsCOMPtr<nsIAccessibleDocument>(GetDocAccessible()));
  if (docAccessible) {
    PRBool isEditable;
    docAccessible->GetIsEditable(&isEditable);
    if (isEditable) {
      *aState &= ~(STATE_FOCUSED | STATE_FOCUSABLE); // Links not focusable in editor
    }
  }
  return NS_OK;
}


NS_IMETHODIMP nsLinkableAccessible::GetValue(nsAString& _retval)
{
  if (mIsLink) {
    nsCOMPtr<nsIDOMNode> linkNode(do_QueryInterface(mActionContent));
    nsCOMPtr<nsIPresShell> presShell(do_QueryReferent(mWeakShell));
    if (linkNode && presShell)
      return presShell->GetLinkLocation(linkNode, _retval);
  }
  return NS_ERROR_NOT_IMPLEMENTED;
}


/* PRUint8 getAccNumActions (); */
NS_IMETHODIMP nsLinkableAccessible::GetNumActions(PRUint8 *aNumActions)
{
  *aNumActions = mActionContent ? 1 : 0;
  return NS_OK;
}

/* wstring getAccActionName (in PRUint8 index); */
NS_IMETHODIMP nsLinkableAccessible::GetActionName(PRUint8 index, nsAString& aActionName)
{
  // Action 0 (default action): Jump to link
  aActionName.Truncate();
  if (index == eAction_Jump) {   
    if (mIsLink) {
      return nsAccessible::GetTranslatedString(NS_LITERAL_STRING("jump"), aActionName); 
    }
    else if (mIsOnclick) {
      return nsAccessible::GetTranslatedString(NS_LITERAL_STRING("click"), aActionName); 
    }
    return NS_ERROR_NOT_IMPLEMENTED;
  }
  return NS_ERROR_INVALID_ARG;
}

/* void accDoAction (in PRUint8 index); */
NS_IMETHODIMP nsLinkableAccessible::DoAction(PRUint8 index)
{
  // Action 0 (default action): Jump to link
  if (index == eAction_Jump) {
    if (mActionContent) {
      return DoCommand(mActionContent);
    }
  }
  return NS_ERROR_INVALID_ARG;
}

NS_IMETHODIMP nsLinkableAccessible::GetKeyboardShortcut(nsAString& aKeyboardShortcut)
{
  if (mActionContent) {
    nsCOMPtr<nsIDOMNode> actionNode(do_QueryInterface(mActionContent));
    if (actionNode && mDOMNode != actionNode) {
      nsCOMPtr<nsIAccessible> accessible;
      nsCOMPtr<nsIAccessibilityService> accService = 
        do_GetService("@mozilla.org/accessibilityService;1");
      accService->GetAccessibleInWeakShell(actionNode, mWeakShell,
                                           getter_AddRefs(accessible));
      if (accessible) {
        accessible->GetKeyboardShortcut(aKeyboardShortcut);
      }
      return NS_OK;
    }
  }
  return nsAccessible::GetKeyboardShortcut(aKeyboardShortcut);
}

void nsLinkableAccessible::CacheActionContent()
{
  for (nsCOMPtr<nsIContent> walkUpContent(do_QueryInterface(mDOMNode));
       walkUpContent;
       walkUpContent = walkUpContent->GetParent()) {
    nsIAtom *tag = walkUpContent->Tag();
    if ((tag == nsAccessibilityAtoms::a || tag == nsAccessibilityAtoms::area)) {
      // Currently we do not expose <link> tags, because they are not typically
      // in <body> and rendered.
      // We do not yet support xlinks
      nsCOMPtr<nsILink> link = do_QueryInterface(walkUpContent);
      NS_ASSERTION(link, "No nsILink for area or a");
      nsCOMPtr<nsIURI> uri;
      link->GetHrefURI(getter_AddRefs(uri));
      if (uri) {
        mActionContent = walkUpContent;
        mIsLink = PR_TRUE;
        break;
      }
    }
    if (walkUpContent->HasAttr(kNameSpaceID_None,
                            nsAccessibilityAtoms::onclick)) {
      mActionContent = walkUpContent;
      mIsOnclick = PR_TRUE;
      break;
    }
  }
}

// nsIAccessibleHyperLink::GetURI()
NS_IMETHODIMP nsLinkableAccessible::GetURI(PRInt32 aIndex, nsIURI **aURI)
{
  // XXX Also implement this for nsHTMLImageAccessible file names
  *aURI = nsnull;
  if (aIndex != 0 || !mIsLink || !SameCOMIdentity(mDOMNode, mActionContent)) {
    return NS_ERROR_FAILURE;
  }

  nsCOMPtr<nsILink> link(do_QueryInterface(mActionContent));
  if (link) {
    return link->GetHrefURI(aURI);
  }

  return NS_ERROR_FAILURE;
}

NS_IMETHODIMP nsLinkableAccessible::Init()
{
  CacheActionContent();
  return nsHyperTextAccessible::Init();
}

NS_IMETHODIMP nsLinkableAccessible::Shutdown()
{
  mActionContent = nsnull;
  return nsHyperTextAccessible::Shutdown();
}

//---------------------
// nsEnumRoleAccessible
//---------------------

nsEnumRoleAccessible::nsEnumRoleAccessible(nsIDOMNode* aNode, nsIWeakReference* aShell, PRUint32 aRole) :
  nsAccessibleWrap(aNode, aShell),
  mRole(aRole)
{
}

NS_IMPL_ISUPPORTS_INHERITED0(nsEnumRoleAccessible, nsAccessible)