nsSMILValue
SVGAnimatedLengthList::SMILAnimatedLengthList::GetBaseValue() const
{
// To benefit from Return Value Optimization and avoid copy constructor calls
// due to our use of return-by-value, we must return the exact same object
// from ALL return points. This function must only return THIS variable:
nsSMILValue val;
nsSMILValue tmp(&SVGLengthListSMILType::sSingleton);
SVGLengthListAndInfo *llai = static_cast<SVGLengthListAndInfo*>(tmp.mU.mPtr);
nsresult rv = llai->CopyFrom(mVal->mBaseVal);
if (NS_SUCCEEDED(rv)) {
llai->SetInfo(mElement, mAxis, mCanZeroPadList);
val.Swap(tmp);
}
return val;
}
nsresult
SVGAnimatedLengthList::
SMILAnimatedLengthList::ValueFromString(const nsAString& aStr,
const nsISMILAnimationElement* /*aSrcElement*/,
nsSMILValue& aValue,
bool& aPreventCachingOfSandwich) const
{
nsSMILValue val(&SVGLengthListSMILType::sSingleton);
SVGLengthListAndInfo *llai = static_cast<SVGLengthListAndInfo*>(val.mU.mPtr);
nsresult rv = llai->SetValueFromString(aStr);
if (NS_SUCCEEDED(rv)) {
llai->SetInfo(mElement, mAxis, mCanZeroPadList);
aValue.Swap(val);
// If any of the lengths in the list depend on their context, then we must
// prevent caching of the entire animation sandwich. This is because the
// units of a length at a given index can change from sandwich layer to
// layer, and indeed even be different within a single sandwich layer. If
// any length in the result of an animation sandwich is the result of the
// addition of lengths where one or more of those lengths is context
// dependent, then naturally the resultant length is also context
// dependent, regardless of whether its actual unit is context dependent or
// not. Unfortunately normal invalidation mechanisms won't cause us to
// recalculate the result of the sandwich if the context changes, so we
// take the (substantial) performance hit of preventing caching of the
// sandwich layer, causing the animation sandwich to be recalculated every
// single sample.
aPreventCachingOfSandwich = PR_FALSE;
for (PRUint32 i = 0; i < llai->Length(); ++i) {
PRUint8 unit = (*llai)[i].GetUnit();
if (unit == nsIDOMSVGLength::SVG_LENGTHTYPE_PERCENTAGE ||
unit == nsIDOMSVGLength::SVG_LENGTHTYPE_EMS ||
unit == nsIDOMSVGLength::SVG_LENGTHTYPE_EXS) {
aPreventCachingOfSandwich = PR_TRUE;
break;
}
}
}
return rv;
}