void
DOMSVGPathSegList::
  MaybeRemoveItemFromAnimValListAt(uint32_t aIndex,
                                   uint32_t aArgCountForItem)
{
  NS_ABORT_IF_FALSE(!IsAnimValList(), "call from baseVal to animVal");

  if (AttrIsAnimating()) {
    // animVal not a clone of baseVal
    return;
  }

  // This needs to be a strong reference; otherwise, the RemovingFromList call
  // below might drop the last reference to animVal before we're done with it.
  nsRefPtr<DOMSVGPathSegList> animVal =
    GetDOMWrapperIfExists(InternalAList().GetAnimValKey());
  if (!animVal) {
    // No animVal list wrapper
    return;
  }

  NS_ABORT_IF_FALSE(animVal->mItems.Length() == mItems.Length(),
                    "animVal list not in sync!");

  if (animVal->ItemAt(aIndex)) {
    animVal->ItemAt(aIndex)->RemovingFromList();
  }
  animVal->mItems.RemoveElementAt(aIndex);

  animVal->UpdateListIndicesFromIndex(aIndex, -(1 + aArgCountForItem));
}

void
DOMSVGPathSegList::EnsureItemAt(uint32_t aIndex)
{
  if (!ItemAt(aIndex)) {
    ItemAt(aIndex) = DOMSVGPathSeg::CreateFor(this, aIndex, IsAnimValList());
  }
}

void
DOMSVGPathSegList::
  MaybeInsertNullInAnimValListAt(uint32_t aIndex,
                                 uint32_t aInternalIndex,
                                 uint32_t aArgCountForItem)
{
  NS_ABORT_IF_FALSE(!IsAnimValList(), "call from baseVal to animVal");

  if (AttrIsAnimating()) {
    // animVal not a clone of baseVal
    return;
  }

  // The anim val list is in sync with the base val list
  DOMSVGPathSegList *animVal =
    GetDOMWrapperIfExists(InternalAList().GetAnimValKey());
  if (!animVal) {
    // No animVal list wrapper
    return;
  }

  NS_ABORT_IF_FALSE(animVal->mItems.Length() == mItems.Length(),
                    "animVal list not in sync!");

  animVal->mItems.InsertElementAt(aIndex, ItemProxy(nullptr, aInternalIndex));

  animVal->UpdateListIndicesFromIndex(aIndex + 1, 1 + aArgCountForItem);
}

void
DOMSVGPointList::MaybeInsertNullInAnimValListAt(PRUint32 aIndex)
{
  NS_ABORT_IF_FALSE(!IsAnimValList(), "call from baseVal to animVal");

  if (AttrIsAnimating()) {
    // animVal not a clone of baseVal
    return;
  }

  // The anim val list is in sync with the base val list
  DOMSVGPointList *animVal =
    GetDOMWrapperIfExists(InternalAList().GetAnimValKey());
  if (!animVal) {
    // No animVal list wrapper
    return;
  }

  NS_ABORT_IF_FALSE(animVal->mItems.Length() == mItems.Length(),
                    "animVal list not in sync!");

  animVal->mItems.InsertElementAt(aIndex, static_cast<DOMSVGPoint*>(nsnull));

  UpdateListIndicesFromIndex(animVal->mItems, aIndex + 1);
}

already_AddRefed<DOMSVGPathSeg>
DOMSVGPathSegList::Initialize(DOMSVGPathSeg& aNewItem, ErrorResult& aError)
{
  if (IsAnimValList()) {
    aError.Throw(NS_ERROR_DOM_NO_MODIFICATION_ALLOWED_ERR);
    return nullptr;
  }

  // If aNewItem is already in a list we should insert a clone of aNewItem,
  // and for consistency, this should happen even if *this* is the list that
  // aNewItem is currently in. Note that in the case of aNewItem being in this
  // list, the Clear() call before the InsertItemBefore() call would remove it
  // from this list, and so the InsertItemBefore() call would not insert a
  // clone of aNewItem, it would actually insert aNewItem. To prevent that
  // from happening we have to do the clone here, if necessary.

  nsRefPtr<DOMSVGPathSeg> domItem = &aNewItem;
  if (aNewItem.HasOwner()) {
    domItem = aNewItem.Clone();
  }

  Clear(aError);
  MOZ_ASSERT(!aError.Failed(), "How could this fail?");
  return InsertItemBefore(*domItem, 0, aError);
}

NS_IMETHODIMP
DOMSVGPointList::Initialize(nsIDOMSVGPoint *aNewItem,
                            nsIDOMSVGPoint **_retval)
{
  *_retval = nsnull;
  if (IsAnimValList()) {
    return NS_ERROR_DOM_NO_MODIFICATION_ALLOWED_ERR;
  }

  // If aNewItem is already in a list we should insert a clone of aNewItem,
  // and for consistency, this should happen even if *this* is the list that
  // aNewItem is currently in. Note that in the case of aNewItem being in this
  // list, the Clear() call before the InsertItemBefore() call would remove it
  // from this list, and so the InsertItemBefore() call would not insert a
  // clone of aNewItem, it would actually insert aNewItem. To prevent that
  // from happening we have to do the clone here, if necessary.

  nsCOMPtr<DOMSVGPoint> domItem = do_QueryInterface(aNewItem);
  if (!domItem) {
    return NS_ERROR_DOM_SVG_WRONG_TYPE_ERR;
  }
  if (domItem->HasOwner() || domItem->IsReadonly()) {
    aNewItem = domItem->Clone();
  }

  Clear();
  return InsertItemBefore(aNewItem, 0, _retval);
}

void
DOMSVGPointList::EnsureItemAt(PRUint32 aIndex)
{
  if (!mItems[aIndex]) {
    mItems[aIndex] = new DOMSVGPoint(this, aIndex, IsAnimValList());
  }
}

NS_IMETHODIMP
DOMSVGPointList::Clear()
{
  if (IsAnimValList()) {
    return NS_ERROR_DOM_NO_MODIFICATION_ALLOWED_ERR;
  }

  if (Length() > 0) {
    nsAttrValue emptyOrOldValue = Element()->WillChangePointList();
    // DOM list items that are to be removed must be removed before we change
    // the internal list, otherwise they wouldn't be able to copy their
    // internal counterparts' values!

    InternalListWillChangeTo(SVGPointList()); // clears mItems

    if (!AttrIsAnimating()) {
      // The anim val list is in sync with the base val list
      DOMSVGPointList *animList =
        GetDOMWrapperIfExists(InternalAList().GetAnimValKey());
      if (animList) {
        animList->InternalListWillChangeTo(SVGPointList()); // clears its mItems
      }
    }

    InternalList().Clear();
    Element()->DidChangePointList(emptyOrOldValue);
    if (AttrIsAnimating()) {
      Element()->AnimationNeedsResample();
    }
  }
  return NS_OK;
}

void
DOMSVGLengthList::EnsureItemAt(PRUint32 aIndex)
{
  if (!mItems[aIndex]) {
    mItems[aIndex] = new DOMSVGLength(this, AttrEnum(), aIndex, IsAnimValList());
  }
}

already_AddRefed<nsISVGPoint>
DOMSVGPointList::Initialize(nsISVGPoint& aNewItem, ErrorResult& aError)
{
  if (IsAnimValList()) {
    aError.Throw(NS_ERROR_DOM_NO_MODIFICATION_ALLOWED_ERR);
    return nullptr;
  }

  // If aNewItem is already in a list we should insert a clone of aNewItem,
  // and for consistency, this should happen even if *this* is the list that
  // aNewItem is currently in. Note that in the case of aNewItem being in this
  // list, the Clear() call before the InsertItemBefore() call would remove it
  // from this list, and so the InsertItemBefore() call would not insert a
  // clone of aNewItem, it would actually insert aNewItem. To prevent that
  // from happening we have to do the clone here, if necessary.

  nsCOMPtr<nsISVGPoint> domItem = &aNewItem;
  if (domItem->HasOwner() || domItem->IsReadonly()) {
    domItem = domItem->Clone(); // must do this before changing anything!
  }

  ErrorResult rv;
  Clear(rv);
  MOZ_ASSERT(!rv.Failed());
  return InsertItemBefore(*domItem, 0, aError);
}

already_AddRefed<SVGTransform>
DOMSVGTransformList::Initialize(SVGTransform& newItem, ErrorResult& error)
{
  if (IsAnimValList()) {
    error.Throw(NS_ERROR_DOM_NO_MODIFICATION_ALLOWED_ERR);
    return nullptr;
  }

  // If newItem is already in a list we should insert a clone of newItem, and
  // for consistency, this should happen even if *this* is the list that
  // newItem is currently in. Note that in the case of newItem being in this
  // list, the Clear() call before the InsertItemBefore() call would remove it
  // from this list, and so the InsertItemBefore() call would not insert a
  // clone of newItem, it would actually insert newItem. To prevent that from
  // happening we have to do the clone here, if necessary.

  nsRefPtr<SVGTransform> domItem = &newItem;
  if (domItem->HasOwner()) {
    domItem = newItem.Clone();
  }

  Clear(error);
  MOZ_ASSERT(!error.Failed(), "How could this fail?");
  return InsertItemBefore(*domItem, 0, error);
}

void
DOMSVGPathSegList::
  MaybeRemoveItemFromAnimValListAt(PRUint32 aIndex,
                                   PRUint32 aArgCountForItem)
{
  NS_ABORT_IF_FALSE(!IsAnimValList(), "call from baseVal to animVal");

  if (AttrIsAnimating()) {
    // animVal not a clone of baseVal
    return;
  }

  DOMSVGPathSegList *animVal =
    GetDOMWrapperIfExists(InternalAList().GetAnimValKey());
  if (!animVal) {
    // No animVal list wrapper
    return;
  }

  NS_ABORT_IF_FALSE(animVal->mItems.Length() == mItems.Length(),
                    "animVal list not in sync!");

  if (animVal->ItemAt(aIndex)) {
    animVal->ItemAt(aIndex)->RemovingFromList();
  }
  animVal->mItems.RemoveElementAt(aIndex);

  animVal->UpdateListIndicesFromIndex(aIndex, -(1 + aArgCountForItem));
}

void
DOMSVGPathSegList::Clear(ErrorResult& aError)
{
  if (IsAnimValList()) {
    aError.Throw(NS_ERROR_DOM_NO_MODIFICATION_ALLOWED_ERR);
    return;
  }

  if (LengthNoFlush() > 0) {
    AutoChangePathSegListNotifier notifier(this);
    // DOM list items that are to be removed must be removed before we change
    // the internal list, otherwise they wouldn't be able to copy their
    // internal counterparts' values!

    InternalListWillChangeTo(SVGPathData()); // clears mItems

    if (!AttrIsAnimating()) {
      // The anim val list is in sync with the base val list
      DOMSVGPathSegList *animList =
        GetDOMWrapperIfExists(InternalAList().GetAnimValKey());
      if (animList) {
        animList->InternalListWillChangeTo(SVGPathData()); // clears its mItems
      }
    }

    InternalList().Clear();
  }
}

void
DOMSVGPointList::MaybeRemoveItemFromAnimValListAt(uint32_t aIndex)
{
  MOZ_ASSERT(!IsAnimValList(), "call from baseVal to animVal");

  if (!AnimListMirrorsBaseList()) {
    return;
  }

  // This needs to be a strong reference; otherwise, the RemovingFromList call
  // below might drop the last reference to animVal before we're done with it.
  RefPtr<DOMSVGPointList> animVal =
    GetDOMWrapperIfExists(InternalAList().GetAnimValKey());

  MOZ_ASSERT(animVal, "AnimListMirrorsBaseList() promised a non-null animVal");
  MOZ_ASSERT(animVal->mItems.Length() == mItems.Length(),
             "animVal list not in sync!");

  if (animVal->mItems[aIndex]) {
    animVal->mItems[aIndex]->RemovingFromList();
  }
  animVal->mItems.RemoveElementAt(aIndex);

  UpdateListIndicesFromIndex(animVal->mItems, aIndex);
}

already_AddRefed<SVGTransform>
DOMSVGTransformList::RemoveItem(uint32_t index, ErrorResult& error)
{
  if (IsAnimValList()) {
    error.Throw(NS_ERROR_DOM_NO_MODIFICATION_ALLOWED_ERR);
    return nullptr;
  }

  if (index >= LengthNoFlush()) {
    error.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
    return nullptr;
  }

  AutoChangeTransformListNotifier notifier(this);
  // Now that we know we're removing, keep animVal list in sync as necessary.
  // Do this *before* touching InternalList() so the removed item can get its
  // internal value.
  MaybeRemoveItemFromAnimValListAt(index);

  // We have to return the removed item, so get it, creating it if necessary:
  nsRefPtr<SVGTransform> result = GetItemAt(index);

  // Notify the DOM item of removal *before* modifying the lists so that the
  // DOM item can copy its *old* value:
  result->RemovingFromList();

  InternalList().RemoveItem(index);
  mItems.RemoveElementAt(index);

  UpdateListIndicesFromIndex(mItems, index);

  return result.forget();
}

already_AddRefed<nsISVGPoint>
DOMSVGPointList::InsertItemBefore(nsISVGPoint& aNewItem, uint32_t aIndex,
                                  ErrorResult& aError)
{
  if (IsAnimValList()) {
    aError.Throw(NS_ERROR_DOM_NO_MODIFICATION_ALLOWED_ERR);
    return nullptr;
  }

  aIndex = std::min(aIndex, LengthNoFlush());
  if (aIndex >= nsISVGPoint::MaxListIndex()) {
    aError.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
    return nullptr;
  }

  nsCOMPtr<nsISVGPoint> domItem = &aNewItem;
  if (domItem->HasOwner() || domItem->IsReadonly()) {
    domItem = domItem->Clone(); // must do this before changing anything!
  }

  // Ensure we have enough memory so we can avoid complex error handling below:
  if (!mItems.SetCapacity(mItems.Length() + 1) ||
      !InternalList().SetCapacity(InternalList().Length() + 1)) {
    aError.Throw(NS_ERROR_OUT_OF_MEMORY);
    return nullptr;
  }

  nsAttrValue emptyOrOldValue = Element()->WillChangePointList();
  // Now that we know we're inserting, keep animVal list in sync as necessary.
  MaybeInsertNullInAnimValListAt(aIndex);

  InternalList().InsertItem(aIndex, domItem->ToSVGPoint());
  mItems.InsertElementAt(aIndex, domItem);

  // This MUST come after the insertion into InternalList(), or else under the
  // insertion into InternalList() the values read from domItem would be bad
  // data from InternalList() itself!:
  domItem->InsertingIntoList(this, aIndex, IsAnimValList());

  UpdateListIndicesFromIndex(mItems, aIndex + 1);

  Element()->DidChangePointList(emptyOrOldValue);
  if (AttrIsAnimating()) {
    Element()->AnimationNeedsResample();
  }
  return domItem.forget();
}

NS_IMETHODIMP
DOMSVGLengthList::GetNumberOfItems(PRUint32 *aNumberOfItems)
{
  if (IsAnimValList()) {
    Element()->FlushAnimations();
  }
  *aNumberOfItems = Length();
  return NS_OK;
}

NS_IMETHODIMP
DOMSVGLengthList::InsertItemBefore(nsIDOMSVGLength *newItem,
                                   PRUint32 index,
                                   nsIDOMSVGLength **_retval)
{
  *_retval = nsnull;
  if (IsAnimValList()) {
    return NS_ERROR_DOM_NO_MODIFICATION_ALLOWED_ERR;
  }

  nsCOMPtr<DOMSVGLength> domItem = do_QueryInterface(newItem);
  if (!domItem) {
    return NS_ERROR_DOM_SVG_WRONG_TYPE_ERR;
  }
  index = NS_MIN(index, Length());
  SVGLength length = domItem->ToSVGLength(); // get before setting domItem
  if (domItem->HasOwner()) {
    domItem = new DOMSVGLength();
  }
  PRBool ok = !!InternalList().InsertItem(index, length);
  if (!ok) {
    return NS_ERROR_OUT_OF_MEMORY;
  }
  domItem->InsertingIntoList(this, AttrEnum(), index, IsAnimValList());
  ok = !!mItems.InsertElementAt(index, domItem.get());
  if (!ok) {
    InternalList().RemoveItem(index);
    return NS_ERROR_OUT_OF_MEMORY;
  }
  for (PRUint32 i = index + 1; i < Length(); ++i) {
    if (mItems[i]) {
      mItems[i]->UpdateListIndex(i);
    }
  }
  Element()->DidChangeLengthList(AttrEnum(), PR_TRUE);
#ifdef MOZ_SMIL
  if (mAList->IsAnimating()) {
    Element()->AnimationNeedsResample();
  }
#endif
  *_retval = domItem.forget().get();
  return NS_OK;
}

NS_IMETHODIMP
DOMSVGNumberList::ReplaceItem(nsIDOMSVGNumber *newItem,
                              PRUint32 index,
                              nsIDOMSVGNumber **_retval)
{
  *_retval = nsnull;
  if (IsAnimValList()) {
    return NS_ERROR_DOM_NO_MODIFICATION_ALLOWED_ERR;
  }

  nsCOMPtr<DOMSVGNumber> domItem = do_QueryInterface(newItem);
  if (!domItem) {
    return NS_ERROR_DOM_SVG_WRONG_TYPE_ERR;
  }
  if (index >= Length()) {
    return NS_ERROR_DOM_INDEX_SIZE_ERR;
  }
  if (domItem->HasOwner()) {
    domItem = domItem->Clone(); // must do this before changing anything!
  }

  if (mItems[index]) {
    // Notify any existing DOM item of removal *before* modifying the lists so
    // that the DOM item can copy the *old* value at its index:
    mItems[index]->RemovingFromList();
  }

  InternalList()[index] = domItem->ToSVGNumber();
  mItems[index] = domItem;

  // This MUST come after the ToSVGPoint() call, otherwise that call
  // would end up reading bad data from InternalList()!
  domItem->InsertingIntoList(this, AttrEnum(), index, IsAnimValList());

  Element()->DidChangeNumberList(AttrEnum(), PR_TRUE);
#ifdef MOZ_SMIL
  if (mAList->IsAnimating()) {
    Element()->AnimationNeedsResample();
  }
#endif
  NS_ADDREF(*_retval = domItem.get());
  return NS_OK;
}

already_AddRefed<SVGTransform>
DOMSVGTransformList::InsertItemBefore(SVGTransform& newItem,
                                      uint32_t index, ErrorResult& error)
{
  if (IsAnimValList()) {
    error.Throw(NS_ERROR_DOM_NO_MODIFICATION_ALLOWED_ERR);
    return nullptr;
  }

  index = std::min(index, LengthNoFlush());
  if (index >= SVGTransform::MaxListIndex()) {
    error.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
    return nullptr;
  }

  nsRefPtr<SVGTransform> domItem = &newItem;
  if (newItem.HasOwner()) {
    domItem = newItem.Clone(); // must do this before changing anything!
  }

  // Ensure we have enough memory so we can avoid complex error handling below:
  if (!mItems.SetCapacity(mItems.Length() + 1) ||
      !InternalList().SetCapacity(InternalList().Length() + 1)) {
    error.Throw(NS_ERROR_OUT_OF_MEMORY);
    return nullptr;
  }

  AutoChangeTransformListNotifier notifier(this);
  // Now that we know we're inserting, keep animVal list in sync as necessary.
  MaybeInsertNullInAnimValListAt(index);

  InternalList().InsertItem(index, domItem->ToSVGTransform());
  mItems.InsertElementAt(index, domItem.get());

  // This MUST come after the insertion into InternalList(), or else under the
  // insertion into InternalList() the values read from domItem would be bad
  // data from InternalList() itself!:
  domItem->InsertingIntoList(this, index, IsAnimValList());

  UpdateListIndicesFromIndex(mItems, index + 1);

  return domItem.forget();
}