UXP/dom/base/DOMRect.cpp

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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 "mozilla/dom/DOMRect.h"

#include "nsPresContext.h"
#include "mozilla/dom/DOMRectListBinding.h"
#include "mozilla/dom/DOMRectBinding.h"

using namespace mozilla;
using namespace mozilla::dom;

NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(DOMRectReadOnly, mParent)
NS_IMPL_CYCLE_COLLECTING_ADDREF(DOMRectReadOnly)
NS_IMPL_CYCLE_COLLECTING_RELEASE(DOMRectReadOnly)
NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(DOMRectReadOnly)
  NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
  NS_INTERFACE_MAP_ENTRY(nsISupports)
NS_INTERFACE_MAP_END

JSObject*
DOMRectReadOnly::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto)
{
  MOZ_ASSERT(mParent);
  return DOMRectReadOnlyBinding::Wrap(aCx, this, aGivenProto);
}

already_AddRefed<DOMRectReadOnly>
DOMRectReadOnly::FromRect(const GlobalObject& aGlobal, const DOMRectInit& aInit)
{
  RefPtr<DOMRectReadOnly> obj = new DOMRectReadOnly(
      aGlobal.GetAsSupports(), aInit.mX, aInit.mY, aInit.mWidth, aInit.mHeight);
  return obj.forget();
}

already_AddRefed<DOMRectReadOnly>
DOMRectReadOnly::Constructor(const GlobalObject& aGlobal, double aX, double aY,
                             double aWidth, double aHeight, ErrorResult& aRv)
{
  RefPtr<DOMRectReadOnly> obj =
    new DOMRectReadOnly(aGlobal.GetAsSupports(), aX, aY, aWidth, aHeight);
  return obj.forget();
}

// https://drafts.fxtf.org/geometry/#structured-serialization
bool
DOMRectReadOnly::WriteStructuredClone(JSStructuredCloneWriter* aWriter) const
{
#define WriteDouble(d)                                                       \
  JS_WriteUint32Pair(aWriter, (BitwiseCast<uint64_t>(d) >> 32) & 0xffffffff, \
                     BitwiseCast<uint64_t>(d) & 0xffffffff)

  return WriteDouble(mX) && WriteDouble(mY) && WriteDouble(mWidth) &&
         WriteDouble(mHeight);

#undef WriteDouble
}

bool
DOMRectReadOnly::ReadStructuredClone(JSStructuredCloneReader* aReader)
{
  uint32_t high;
  uint32_t low;

#define ReadDouble(d)                             \
  if (!JS_ReadUint32Pair(aReader, &high, &low)) { \
    return false;                                 \
  }                                               \
  (*(d) = BitwiseCast<double>(static_cast<uint64_t>(high) << 32 | low))

  ReadDouble(&mX);
  ReadDouble(&mY);
  ReadDouble(&mWidth);
  ReadDouble(&mHeight);

  return true;

#undef ReadDouble
}

// -----------------------------------------------------------------------------

NS_IMPL_ISUPPORTS_INHERITED(DOMRect, DOMRectReadOnly, nsIDOMClientRect)

#define FORWARD_GETTER(_name)                                                   \
  NS_IMETHODIMP                                                                 \
  DOMRect::Get ## _name(float* aResult)                                         \
  {                                                                             \
    *aResult = float(_name());                                                  \
    return NS_OK;                                                               \
  }

FORWARD_GETTER(Left)
FORWARD_GETTER(Top)
FORWARD_GETTER(Right)
FORWARD_GETTER(Bottom)
FORWARD_GETTER(Width)
FORWARD_GETTER(Height)

JSObject*
DOMRect::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto)
{
  MOZ_ASSERT(mParent);
  return DOMRectBinding::Wrap(aCx, this, aGivenProto);
}

already_AddRefed<DOMRect>
DOMRect::FromRect(const GlobalObject& aGlobal, const DOMRectInit& aInit)
{
  RefPtr<DOMRect> obj = new DOMRect(aGlobal.GetAsSupports(), aInit.mX, aInit.mY,
                                    aInit.mWidth, aInit.mHeight);
  return obj.forget();
}

already_AddRefed<DOMRect>
DOMRect::Constructor(const GlobalObject& aGlobal, double aX, double aY,
                     double aWidth, double aHeight, ErrorResult& aRv)
{
  RefPtr<DOMRect> obj =
    new DOMRect(aGlobal.GetAsSupports(), aX, aY, aWidth, aHeight);
  return obj.forget();
}

// -----------------------------------------------------------------------------

NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(DOMRectList, mParent, mArray)

NS_INTERFACE_TABLE_HEAD(DOMRectList)
  NS_WRAPPERCACHE_INTERFACE_TABLE_ENTRY
  NS_INTERFACE_TABLE(DOMRectList, nsIDOMClientRectList)
  NS_INTERFACE_TABLE_TO_MAP_SEGUE_CYCLE_COLLECTION(DOMRectList)
NS_INTERFACE_MAP_END

NS_IMPL_CYCLE_COLLECTING_ADDREF(DOMRectList)
NS_IMPL_CYCLE_COLLECTING_RELEASE(DOMRectList)


NS_IMETHODIMP
DOMRectList::GetLength(uint32_t* aLength)
{
  *aLength = Length();
  return NS_OK;
}

NS_IMETHODIMP    
DOMRectList::Item(uint32_t aIndex, nsIDOMClientRect** aReturn)
{
  NS_IF_ADDREF(*aReturn = Item(aIndex));
  return NS_OK;
}

JSObject*
DOMRectList::WrapObject(JSContext *cx, JS::Handle<JSObject*> aGivenProto)
{
  return mozilla::dom::DOMRectListBinding::Wrap(cx, this, aGivenProto);
}

static double
RoundFloat(double aValue)
{
  return floor(aValue + 0.5);
}

void
DOMRect::SetLayoutRect(const nsRect& aLayoutRect)
{
  double scale = 65536.0;
  // Round to the nearest 1/scale units. We choose scale so it can be represented
  // exactly by machine floating point.
  double scaleInv = 1/scale;
  double t2pScaled = scale/nsPresContext::AppUnitsPerCSSPixel();
  double x = RoundFloat(aLayoutRect.x*t2pScaled)*scaleInv;
  double y = RoundFloat(aLayoutRect.y*t2pScaled)*scaleInv;
  SetRect(x, y, RoundFloat(aLayoutRect.XMost()*t2pScaled)*scaleInv - x,
          RoundFloat(aLayoutRect.YMost()*t2pScaled)*scaleInv - y);
}