/// <summary>
/// Returns generator for complex type mappings.
/// </summary>
public static Func<Expression, Type, Expression, Expression> ComplexToComplex(Func<Expression, Type, Expression, Expression> parent, IMemberExtractor memberExtractor)
{
return (fromExpr, to, customMapping) =>
{
if (IsComplexType(fromExpr.Type) && IsComplexType(to))
{
return ValidateCustomMapping(customMapping)
?? ComplexToComplexExpressionGenerator(parent, memberExtractor, fromExpr, to, customMapping);
}
else
{
return null;
}
};
}
private static Expression ComplexToComplexExpressionGenerator(Func<Expression, Type, Expression, Expression> parent, IMemberExtractor memberExtractor, Expression fromExpr, Type to, Expression customMapping)
{
NewExpression configNewExpr = null;
IEnumerable<MemberAssignment> configBindings = Enumerable.Empty<MemberAssignment>();
var customInitExpression = customMapping as MemberInitExpression;
if (customInitExpression != null)
{
configNewExpr = customInitExpression.NewExpression;
configBindings = customInitExpression.Bindings.OfType<MemberAssignment>();
}
var membersTo = memberExtractor
.GetToMembers(to)
.ToList();
var membersFrom = memberExtractor
.GetFromMembers(fromExpr.Type, membersTo)
.ToList();
var conventionalBindings = (from mfrom in membersFrom
join mto in membersTo on mfrom.Name equals mto.Name
let memberExpr = parent(mfrom.GetMemberAccessExpression(fromExpr), mto.Type, null)
where memberExpr != null
select Expression.Bind(mto.Member, memberExpr)
).ToList();
//HACK : In case of no member "from" for custom mapping
//used binding expression as fromExpr parameter for recursive call
//because in this case fromExpr used only for type matching
var customBindings = (from b in configBindings
join mto in membersTo on b.Member equals mto.Member
let mfrom = membersFrom.FirstOrDefault(m => mto.Name == m.Name)
let expr = (mfrom != null)
? mfrom.GetMemberAccessExpression(fromExpr)
: b.Expression /*hack*/
let memberExpr = parent(expr, mto.Type, b.Expression)
select Expression.Bind(mto.Member, memberExpr)
).ToList();
var customBindingMembers = new HashSet<MemberInfo>(customBindings.Select(b => b.Member));
var allBindings = customBindings
.Concat(conventionalBindings
.Where(b => !customBindingMembers.Contains(b.Member)));
return Expression.MemberInit(configNewExpr ?? Expression.New(to), allBindings.Cast<MemberBinding>());
}
