gecko-dev/dom/svg/DOMSVGNumber.cpp

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "DOMSVGNumber.h"
#include "DOMSVGNumberList.h"
#include "DOMSVGAnimatedNumberList.h"
#include "SVGAnimatedNumberList.h"
#include "nsSVGElement.h"
#include "nsError.h"
#include "nsContentUtils.h"  // for NS_ENSURE_FINITE
#include "mozilla/dom/SVGNumberBinding.h"

// See the architecture comment in DOMSVGAnimatedNumberList.h.

namespace mozilla {

// We could use NS_IMPL_CYCLE_COLLECTION(, except that in Unlink() we need to
// clear our list's weak ref to us to be safe. (The other option would be to
// not unlink and rely on the breaking of the other edges in the cycle, as
// NS_SVG_VAL_IMPL_CYCLE_COLLECTION does.)
NS_IMPL_CYCLE_COLLECTION_CLASS(DOMSVGNumber)

NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(DOMSVGNumber)
  // We may not belong to a list, so we must null check tmp->mList.
  if (tmp->mList) {
    tmp->mList->mItems[tmp->mListIndex] = nullptr;
  }
  NS_IMPL_CYCLE_COLLECTION_UNLINK_PRESERVED_WRAPPER
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mList)
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mParent)
NS_IMPL_CYCLE_COLLECTION_UNLINK_END
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(DOMSVGNumber)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mList)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mParent)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN(DOMSVGNumber)
  NS_IMPL_CYCLE_COLLECTION_TRACE_PRESERVED_WRAPPER
NS_IMPL_CYCLE_COLLECTION_TRACE_END

NS_IMPL_CYCLE_COLLECTING_ADDREF(DOMSVGNumber)
NS_IMPL_CYCLE_COLLECTING_RELEASE(DOMSVGNumber)

NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(DOMSVGNumber)
  NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
  NS_INTERFACE_MAP_ENTRY(nsISupports)
NS_INTERFACE_MAP_END

//----------------------------------------------------------------------
// Helper class: AutoChangeNumberNotifier
// Stack-based helper class to pair calls to WillChangeNumberList and
// DidChangeNumberList.
class MOZ_RAII AutoChangeNumberNotifier {
 public:
  explicit AutoChangeNumberNotifier(
      DOMSVGNumber* aNumber MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
      : mNumber(aNumber) {
    MOZ_GUARD_OBJECT_NOTIFIER_INIT;
    MOZ_ASSERT(mNumber, "Expecting non-null number");
    MOZ_ASSERT(mNumber->HasOwner(),
               "Expecting list to have an owner for notification");
    mEmptyOrOldValue =
        mNumber->Element()->WillChangeNumberList(mNumber->mAttrEnum);
  }

  ~AutoChangeNumberNotifier() {
    mNumber->Element()->DidChangeNumberList(mNumber->mAttrEnum,
                                            mEmptyOrOldValue);
    // Null check mNumber->mList, since DidChangeNumberList can run script,
    // potentially removing mNumber from its list.
    if (mNumber->mList && mNumber->mList->IsAnimating()) {
      mNumber->Element()->AnimationNeedsResample();
    }
  }

 private:
  DOMSVGNumber* const mNumber;
  nsAttrValue mEmptyOrOldValue;
  MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
};

DOMSVGNumber::DOMSVGNumber(DOMSVGNumberList* aList, uint8_t aAttrEnum,
                           uint32_t aListIndex, bool aIsAnimValItem)
    : mList(aList),
      mParent(aList),
      mListIndex(aListIndex),
      mAttrEnum(aAttrEnum),
      mIsAnimValItem(aIsAnimValItem),
      mValue(0.0f) {
  // These shifts are in sync with the members in the header.
  MOZ_ASSERT(aList && aAttrEnum < (1 << 4) && aListIndex <= MaxListIndex(),
             "bad arg");

  MOZ_ASSERT(IndexIsValid(), "Bad index for DOMSVGNumber!");
}

DOMSVGNumber::DOMSVGNumber(nsISupports* aParent)
    : mList(nullptr),
      mParent(aParent),
      mListIndex(0),
      mAttrEnum(0),
      mIsAnimValItem(false),
      mValue(0.0f) {}

float DOMSVGNumber::Value() {
  if (mIsAnimValItem && HasOwner()) {
    Element()->FlushAnimations();  // May make HasOwner() == false
  }
  return HasOwner() ? InternalItem() : mValue;
}

void DOMSVGNumber::SetValue(float aValue, ErrorResult& aRv) {
  if (mIsAnimValItem) {
    aRv.Throw(NS_ERROR_DOM_NO_MODIFICATION_ALLOWED_ERR);
    return;
  }

  if (HasOwner()) {
    if (InternalItem() == aValue) {
      return;
    }
    AutoChangeNumberNotifier notifier(this);
    InternalItem() = aValue;
    return;
  }

  mValue = aValue;
}

void DOMSVGNumber::InsertingIntoList(DOMSVGNumberList* aList, uint8_t aAttrEnum,
                                     uint32_t aListIndex, bool aIsAnimValItem) {
  NS_ASSERTION(!HasOwner(), "Inserting item that is already in a list");

  mList = aList;
  mAttrEnum = aAttrEnum;
  mListIndex = aListIndex;
  mIsAnimValItem = aIsAnimValItem;

  MOZ_ASSERT(IndexIsValid(), "Bad index for DOMSVGNumber!");
}

void DOMSVGNumber::RemovingFromList() {
  mValue = InternalItem();
  mList = nullptr;
  mIsAnimValItem = false;
}

float DOMSVGNumber::ToSVGNumber() {
  return HasOwner() ? InternalItem() : mValue;
}

float& DOMSVGNumber::InternalItem() {
  SVGAnimatedNumberList* alist = Element()->GetAnimatedNumberList(mAttrEnum);
  return mIsAnimValItem && alist->mAnimVal ? (*alist->mAnimVal)[mListIndex]
                                           : alist->mBaseVal[mListIndex];
}

#ifdef DEBUG
bool DOMSVGNumber::IndexIsValid() {
  SVGAnimatedNumberList* alist = Element()->GetAnimatedNumberList(mAttrEnum);
  return (mIsAnimValItem && mListIndex < alist->GetAnimValue().Length()) ||
         (!mIsAnimValItem && mListIndex < alist->GetBaseValue().Length());
}
#endif

JSObject* DOMSVGNumber::WrapObject(JSContext* aCx,
                                   JS::Handle<JSObject*> aGivenProto) {
  return dom::SVGNumber_Binding::Wrap(aCx, this, aGivenProto);
}

}  // namespace mozilla