void DOMSVGStringList::IndexedGetter(uint32_t aIndex, bool& aFound,
                                     nsAString& aRetval) {
  aFound = aIndex < InternalList().Length();
  if (aFound) {
    aRetval = InternalList()[aIndex];
  }
}

NS_IMETHODIMP
DOMSVGPathSegList::InsertItemBefore(nsIDOMSVGPathSeg *aNewItem,
                                    PRUint32 aIndex,
                                    nsIDOMSVGPathSeg **_retval)
{
    *_retval = nsnull;
    if (IsAnimValList()) {
        return NS_ERROR_DOM_NO_MODIFICATION_ALLOWED_ERR;
    }

    PRUint32 internalIndex;
    if (aIndex < Length()) {
        internalIndex = mItems[aIndex].mInternalDataIndex;
    } else {
        aIndex = Length();
        internalIndex = InternalList().mData.Length();
    }
    if (aIndex >= DOMSVGPathSeg::MaxListIndex()) {
        return NS_ERROR_DOM_INDEX_SIZE_ERR;
    }

    nsCOMPtr<DOMSVGPathSeg> domItem = do_QueryInterface(aNewItem);
    if (!domItem) {
        return NS_ERROR_DOM_SVG_WRONG_TYPE_ERR;
    }
    if (domItem->HasOwner()) {
        domItem = domItem->Clone(); // must do this before changing anything!
    }

    PRUint32 argCount = SVGPathSegUtils::ArgCountForType(domItem->Type());

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

    // Now that we know we're inserting, keep animVal list in sync as necessary.
    MaybeInsertNullInAnimValListAt(aIndex, internalIndex, argCount);

    float segAsRaw[1 + NS_SVG_PATH_SEG_MAX_ARGS];
    domItem->ToSVGPathSegEncodedData(segAsRaw);

    InternalList().mData.InsertElementsAt(internalIndex, segAsRaw, 1 + argCount);
    mItems.InsertElementAt(aIndex, ItemProxy(domItem.get(), internalIndex));

    // 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(aIndex + 1, argCount + 1);

    Element()->DidChangePathSegList(true);
    if (AttrIsAnimating()) {
        Element()->AnimationNeedsResample();
    }
    *_retval = domItem.forget().get();
    return NS_OK;
}

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

  uint32_t internalIndex;
  if (aIndex < LengthNoFlush()) {
    internalIndex = mItems[aIndex].mInternalDataIndex;
  } else {
    aIndex = LengthNoFlush();
    internalIndex = InternalList().mData.Length();
  }
  if (aIndex >= DOMSVGPathSeg::MaxListIndex()) {
    aError.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
    return nullptr;
  }

  nsRefPtr<DOMSVGPathSeg> domItem = &aNewItem;
  if (domItem->HasOwner()) {
    domItem = domItem->Clone(); // must do this before changing anything!
  }

  uint32_t argCount = SVGPathSegUtils::ArgCountForType(domItem->Type());

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

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

  float segAsRaw[1 + NS_SVG_PATH_SEG_MAX_ARGS];
  domItem->ToSVGPathSegEncodedData(segAsRaw);

  InternalList().mData.InsertElementsAt(internalIndex, segAsRaw, 1 + argCount);
  mItems.InsertElementAt(aIndex, ItemProxy(domItem.get(), internalIndex));

  // 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(aIndex + 1, argCount + 1);

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

void
DOMSVGStringList::Clear()
{
  if (InternalList().IsExplicitlySet()) {
    AutoChangeStringListNotifier notifier(this);
    InternalList().Clear();
  }
}

void DOMSVGStringList::RemoveItem(uint32_t aIndex, nsAString& aRetval,
                                  ErrorResult& aRv) {
  if (aIndex >= InternalList().Length()) {
    aRv.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
    return;
  }

  AutoChangeStringListNotifier notifier(this);
  InternalList().RemoveItem(aIndex);
}

NS_IMETHODIMP
DOMSVGStringList::Clear()
{
  if (InternalList().IsExplicitlySet()) {
    InternalList().Clear();
    mElement->DidChangeStringList(mIsConditionalProcessingAttribute,
                                  mAttrEnum);
  }
  return NS_OK;
}

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->IsTranslatePoint()) {
    domItem = domItem->Copy(); // 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, fallible) ||
      !InternalList().SetCapacity(InternalList().Length() + 1)) {
    aError.Throw(NS_ERROR_OUT_OF_MEMORY);
    return nullptr;
  }
  if (AnimListMirrorsBaseList()) {
    DOMSVGPointList *animVal =
      GetDOMWrapperIfExists(InternalAList().GetAnimValKey());
    MOZ_ASSERT(animVal, "animVal must be a valid pointer");
    if (!animVal->mItems.SetCapacity(
          animVal->mItems.Length() + 1, fallible)) {
      aError.Throw(NS_ERROR_OUT_OF_MEMORY);
      return nullptr;
    }
  }

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

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

  // 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);

  return domItem.forget();
}

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

  aIndex = NS_MIN(aIndex, LengthNoFlush());
  if (aIndex >= DOMSVGPoint::MaxListIndex()) {
    aError.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
    return nullptr;
  }

  nsCOMPtr<DOMSVGPoint> domItem = do_QueryInterface(aNewItem);
  if (!domItem) {
    aError.Throw(NS_ERROR_DOM_SVG_WRONG_TYPE_ERR);
    return nullptr;
  }
  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.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, aIndex, IsAnimValList());

  UpdateListIndicesFromIndex(mItems, aIndex + 1);

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

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

  index = NS_MIN(index, Length());
  if (index >= DOMSVGNumber::MaxListIndex()) {
    return NS_ERROR_DOM_INDEX_SIZE_ERR;
  }

  nsCOMPtr<DOMSVGNumber> domItem = do_QueryInterface(newItem);
  if (!domItem) {
    return NS_ERROR_DOM_SVG_WRONG_TYPE_ERR;
  }
  if (domItem->HasOwner()) {
    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)) {
    return NS_ERROR_OUT_OF_MEMORY;
  }

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

  InternalList().InsertItem(index, domItem->ToSVGNumber());
  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, AttrEnum(), index, IsAnimValList());

  UpdateListIndicesFromIndex(mItems, index + 1);

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

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

  if (Length() > 0) {
    // 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(true);
    if (AttrIsAnimating()) {
      Element()->AnimationNeedsResample();
    }
  }
  return NS_OK;
}

already_AddRefed<SVGTransform>
DOMSVGTransformList::ReplaceItem(SVGTransform& newItem,
                                 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;
  }

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

  AutoChangeTransformListNotifier notifier(this);
  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->ToSVGTransform();
  mItems[index] = domItem;

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

  return domItem.forget();
}

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

  if (LengthNoFlush() == 0) {
    return nullptr;
  }

  // Note that SVG 1.1 says, "The consolidation operation creates new
  // SVGTransform object as the first and only item in the list" hence, even if
  // LengthNoFlush() == 1 we can't return that one item (after making it a
  // matrix type). We must orphan the existing item and then make a new one.

  // First calculate our matrix
  gfxMatrix mx = InternalList().GetConsolidationMatrix();

  // Then orphan the existing items
  Clear(error);
  MOZ_ASSERT(!error.Failed(), "How could this fail?");

  // And append the new transform
  nsRefPtr<SVGTransform> transform = new SVGTransform(mx);
  return InsertItemBefore(*transform, LengthNoFlush(), error);
}

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

  if (aIndex >= LengthNoFlush()) {
    aError.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
    return nullptr;
  }

  AutoChangePointListNotifier 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(aIndex);

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

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

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

  UpdateListIndicesFromIndex(mItems, aIndex);

  return result.forget();
}

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

  if (LengthNoFlush() > 0) {
    nsAttrValue emptyOrOldValue = Element()->WillChangePathSegList();
    // 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();
    Element()->DidChangePathSegList(emptyOrOldValue);
    if (AttrIsAnimating()) {
      Element()->AnimationNeedsResample();
    }
  }
}

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;
  }

  nsAttrValue emptyOrOldValue = Element()->WillChangeTransformList();
  // 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);

  Element()->DidChangeTransformList(emptyOrOldValue);
  if (mAList->IsAnimating()) {
    Element()->AnimationNeedsResample();
  }
  return domItem.forget();
}

NS_IMETHODIMP
DOMSVGStringList::RemoveItem(uint32_t index,
                             nsAString & _retval)
{
  if (index >= InternalList().Length()) {
    return NS_ERROR_DOM_INDEX_SIZE_ERR;
  }

  nsAttrValue emptyOrOldValue =
    mElement->WillChangeStringList(mIsConditionalProcessingAttribute,
                                   mAttrEnum);
  InternalList().RemoveItem(index);

  mElement->DidChangeStringList(mIsConditionalProcessingAttribute, mAttrEnum,
                                emptyOrOldValue);
  return NS_OK;
}

already_AddRefed<DOMSVGPathSeg>
DOMSVGPathSegList::RemoveItem(uint32_t aIndex,
                              ErrorResult& aError)
{
  if (IsAnimValList()) {
    aError.Throw(NS_ERROR_DOM_NO_MODIFICATION_ALLOWED_ERR);
    return nullptr;
  }

  if (aIndex >= LengthNoFlush()) {
    aError.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
    return nullptr;
  }
  // We have to return the removed item, so make sure it exists:
  EnsureItemAt(aIndex);

  nsAttrValue emptyOrOldValue = Element()->WillChangePathSegList();
  // Notify the DOM item of removal *before* modifying the lists so that the
  // DOM item can copy its *old* value:
  ItemAt(aIndex)->RemovingFromList();
  nsRefPtr<DOMSVGPathSeg> result = ItemAt(aIndex);

  uint32_t internalIndex = mItems[aIndex].mInternalDataIndex;
  uint32_t segType = SVGPathSegUtils::DecodeType(InternalList().mData[internalIndex]);
  // NOTE: ArgCountForType returns a (small) unsigned value, but we're
  // intentionally putting it in a signed value, because we're going to
  // negate it, and you can't negate an unsigned value.
  int32_t argCount = SVGPathSegUtils::ArgCountForType(segType);

  // 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(aIndex, argCount);

  InternalList().mData.RemoveElementsAt(internalIndex, 1 + argCount);
  mItems.RemoveElementAt(aIndex);

  UpdateListIndicesFromIndex(aIndex, -(argCount + 1));

  Element()->DidChangePathSegList(emptyOrOldValue);
  if (AttrIsAnimating()) {
    Element()->AnimationNeedsResample();
  }
  return result.forget();
}

NS_IMETHODIMP
DOMSVGStringList::InsertItemBefore(const nsAString & newItem,
                                   PRUint32 index,
                                   nsAString & _retval)
{
  index = NS_MIN(index, InternalList().Length());

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

  InternalList().InsertItem(index, newItem);

  mElement->DidChangeStringList(mIsConditionalProcessingAttribute, mAttrEnum);
  _retval = newItem;
  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;
}