private Expression CreateItemEqualityExpression(MemberExpression fromItem, MemberExpression toItem)
{
Expression itemsAreMapEqual;
if (this.aItemMapping.ResolvedMapping is IMappingWithSpecialComparision)
{
itemsAreMapEqual = Expression.Call(
Expression.Constant(this.aItemMapping.ResolvedMapping),
MappingMethods.MapEqual(EnumerableReflection <TFrom> .ItemType, EnumerableReflection <TTo> .ItemType),
fromItem,
toItem
);
}
else
{
Expression fromMapped = fromItem;
if (!(this.aItemMapping.ResolvedMapping is IDirectMapping))
{
fromMapped = Expression.Call(
Expression.Constant(this.aItemMapping.ResolvedMapping),
MappingMethods.Map(EnumerableReflection <TFrom> .ItemType, EnumerableReflection <TTo> .ItemType),
fromMapped
);
}
itemsAreMapEqual = Expression.Call(
Expression.Constant(EqualityComparerMethods.GetEqualityComparer(EnumerableReflection <TTo> .ItemType)),
EqualityComparerMethods.Equals(EnumerableReflection <TTo> .ItemType),
fromMapped,
toItem
);
}
if (this.aEqualityRules != null)
{
var(selectIdFrom, selectIdTo) = this.aEqualityRules.GetIdSelectors();
itemsAreMapEqual = Expression.AndAlso(
Expression.Equal(
ExpressionHelper.Call(
selectIdFrom,
fromItem
),
ExpressionHelper.Call(
selectIdTo,
toItem
)
),
itemsAreMapEqual
);
}
return(itemsAreMapEqual);
}
public Expression CreateComparisionExpression(ParameterExpression from, ParameterExpression to, LabelTarget end)
{
if (this.Mapping.ResolvedMapping is IMappingWithSpecialComparision)
{
return(Expression.IfThen(
Expression.Not(
Expression.Call(
Expression.Constant(this.Mapping.ResolvedMapping),
MappingMethods.MapEqual(this.From.Type, this.To.Type),
this.From.CreateGetterExpression(from),
this.To.CreateGetterExpression(to)
)
),
Expression.Return(end, Expression.Constant(false))
));
}
else
{
var fromMapped = this.From.CreateGetterExpression(from);
if (!(this.Mapping.ResolvedMapping is IDirectMapping))
{
fromMapped = Expression.Call(
Expression.Constant(this.Mapping.ResolvedMapping),
MappingMethods.Map(this.From.Type, this.To.Type),
fromMapped
);
}
return(Expression.IfThen(
Expression.Not(
Expression.Call(
Expression.Constant(EqualityComparerMethods.GetEqualityComparer(this.To.Type)),
EqualityComparerMethods.Equals(this.To.Type),
fromMapped,
this.To.CreateGetterExpression(to)
)
),
Expression.Return(end, Expression.Constant(false))
));
}
}
