gecko/accessible/src/mac/nsAccessibleWrap.mm

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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 * 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
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 * 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
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 * Portions created by the Initial Developer are Copyright (C) 2006
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Original Author: Håkan Waara <hwaara@gmail.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 "nsDocAccessible.h"
#include "nsObjCExceptions.h"

#import "nsRoleMap.h"

#import "mozAccessibleWrapper.h"
#import "mozAccessible.h"
#import "mozActionElements.h"
#import "mozTextAccessible.h"

nsAccessibleWrap::
  nsAccessibleWrap(nsIContent *aContent, nsIWeakReference *aShell) :
  nsAccessible(aContent, aShell), mNativeWrapper(nsnull)
{
}

nsAccessibleWrap::~nsAccessibleWrap()
{
  if (mNativeWrapper) {
    delete mNativeWrapper;
    mNativeWrapper = nsnull;
  }
}

bool
nsAccessibleWrap::Init () 
{
  if (!nsAccessible::Init())
    return false;

  if (!mNativeWrapper && !AncestorIsFlat()) {
    // Create our native object using the class type specified in GetNativeType().
    mNativeWrapper = new AccessibleWrapper (this, GetNativeType());
    if (!mNativeWrapper)
      return false;
  }

  return true;
}

NS_IMETHODIMP
nsAccessibleWrap::GetNativeInterface (void **aOutInterface) 
{
  if (mNativeWrapper) {
    *aOutInterface = (void**)mNativeWrapper->getNativeObject();
    return NS_OK;
  }
  return NS_ERROR_FAILURE;
}

// overridden in subclasses to create the right kind of object. by default we create a generic
// 'mozAccessible' node.
Class
nsAccessibleWrap::GetNativeType () 
{
  NS_OBJC_BEGIN_TRY_ABORT_BLOCK_NIL;

  PRUint32 role = Role();
  switch (role) {
    case nsIAccessibleRole::ROLE_PUSHBUTTON:
    case nsIAccessibleRole::ROLE_SPLITBUTTON:
    case nsIAccessibleRole::ROLE_TOGGLE_BUTTON:
    {
      // if this button may show a popup, let's make it of the popupbutton type.
      if (HasPopup())
        return [mozPopupButtonAccessible class];
        
      // regular button
      return [mozButtonAccessible class];
    }
    
    case nsIAccessibleRole::ROLE_CHECKBUTTON:
      return [mozCheckboxAccessible class];
      
    case nsIAccessibleRole::ROLE_AUTOCOMPLETE:
      return [mozComboboxAccessible class];
      
    case nsIAccessibleRole::ROLE_ENTRY:
    case nsIAccessibleRole::ROLE_STATICTEXT:
    case nsIAccessibleRole::ROLE_HEADING:
    case nsIAccessibleRole::ROLE_LABEL:
    case nsIAccessibleRole::ROLE_CAPTION:
    case nsIAccessibleRole::ROLE_ACCEL_LABEL:
    case nsIAccessibleRole::ROLE_TEXT_LEAF:
      // normal textfield (static or editable)
      return [mozTextAccessible class]; 
      
    case nsIAccessibleRole::ROLE_COMBOBOX:
      return [mozPopupButtonAccessible class];
      
    default:
      return [mozAccessible class];
  }
  
  return nil;

  NS_OBJC_END_TRY_ABORT_BLOCK_NIL;
}

// this method is very important. it is fired when an accessible object "dies". after this point
// the object might still be around (because some 3rd party still has a ref to it), but it is
// in fact 'dead'.
void
nsAccessibleWrap::Shutdown ()
{
  if (mNativeWrapper) {
    delete mNativeWrapper;
    mNativeWrapper = nsnull;
  }
  
  nsAccessible::Shutdown();
}

nsresult
nsAccessibleWrap::HandleAccEvent(AccEvent* aEvent)
{
  NS_OBJC_BEGIN_TRY_ABORT_BLOCK_NSRESULT;

  nsresult rv = nsAccessible::HandleAccEvent(aEvent);
  NS_ENSURE_SUCCESS(rv, rv);

  return FirePlatformEvent(aEvent);

  NS_OBJC_END_TRY_ABORT_BLOCK_NSRESULT;
}

nsresult
nsAccessibleWrap::FirePlatformEvent(AccEvent* aEvent)
{
  NS_OBJC_BEGIN_TRY_ABORT_BLOCK_NSRESULT;

  PRUint32 eventType = aEvent->GetEventType();

  // ignore everything but focus-changed and value-changed events for now.
  if (eventType != nsIAccessibleEvent::EVENT_FOCUS &&
      eventType != nsIAccessibleEvent::EVENT_VALUE_CHANGE)
    return NS_OK;

  nsAccessible *accessible = aEvent->GetAccessible();
  NS_ENSURE_STATE(accessible);

  mozAccessible *nativeAcc = nil;
  accessible->GetNativeInterface((void**)&nativeAcc);
  if (!nativeAcc)
    return NS_ERROR_FAILURE;

  switch (eventType) {
    case nsIAccessibleEvent::EVENT_FOCUS:
      [nativeAcc didReceiveFocus];
      break;
    case nsIAccessibleEvent::EVENT_VALUE_CHANGE:
      [nativeAcc valueDidChange];
      break;
  }

  return NS_OK;

  NS_OBJC_END_TRY_ABORT_BLOCK_NSRESULT;
}

void
nsAccessibleWrap::InvalidateChildren()
{
  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;

  if (mNativeWrapper) {
    mozAccessible *object = mNativeWrapper->getNativeObject();
    [object invalidateChildren];
  }
  nsAccessible::InvalidateChildren();

  NS_OBJC_END_TRY_ABORT_BLOCK;
}

// if we for some reason have no native accessible, we should be skipped over (and traversed)
// when fetching all unignored children, etc.  when counting unignored children, we will not be counted.
bool 
nsAccessibleWrap::IsIgnored() 
{
  return (mNativeWrapper == nsnull) || mNativeWrapper->isIgnored();
}

void
nsAccessibleWrap::GetUnignoredChildren(nsTArray<nsRefPtr<nsAccessibleWrap> > &aChildrenArray)
{
  // we're flat; there are no children.
  if (nsAccUtils::MustPrune(this))
    return;

  PRInt32 childCount = GetChildCount();
  for (PRInt32 childIdx = 0; childIdx < childCount; childIdx++) {
    nsAccessibleWrap *childAcc =
      static_cast<nsAccessibleWrap*>(GetChildAt(childIdx));

    if (childAcc->IsIgnored()) {
      // element is ignored, so try adding its children as substitutes, if it has any.
      if (!nsAccUtils::MustPrune(childAcc)) {
        nsTArray<nsRefPtr<nsAccessibleWrap> > children;
        childAcc->GetUnignoredChildren(children);
        if (!children.IsEmpty()) {
          // add the found unignored descendants to the array.
          aChildrenArray.AppendElements(children);
        }
      }
    } else
      // simply add the element, since it's not ignored.
      aChildrenArray.AppendElement(childAcc);
  }
}

already_AddRefed<nsIAccessible>
nsAccessibleWrap::GetUnignoredParent()
{
  nsAccessibleWrap* parentWrap = static_cast<nsAccessibleWrap*>(Parent());
  if (!parentWrap)
    return nsnull;
    
  // recursively return the parent, until we find one that is not ignored.
  if (parentWrap->IsIgnored())
    return parentWrap->GetUnignoredParent();
  
  nsIAccessible *outValue = nsnull;
  NS_IF_ADDREF(outValue = parentWrap);
  
  return outValue;
}

////////////////////////////////////////////////////////////////////////////////
// nsAccessibleWrap protected

bool
nsAccessibleWrap::AncestorIsFlat()
{
  // We don't create a native object if we're child of a "flat" accessible;
  // for example, on OS X buttons shouldn't have any children, because that
  // makes the OS confused. 
  //
  // To maintain a scripting environment where the XPCOM accessible hierarchy
  // look the same on all platforms, we still let the C++ objects be created
  // though.

  nsAccessible* parent = Parent();
  while (parent) {
    if (nsAccUtils::MustPrune(parent))
      return true;

    parent = parent->Parent();
  }
  // no parent was flat
  return false;
}