private Expression BuildWriterItem(IMappingAssociation association, Expression from, Expression to, ParameterExpression explicitProperties)
{
if ((association.Direction & MappingDirection.Write) != MappingDirection.Write)
{
return(null);
}
var converter = association as IConvertionAssociation;
var component = association as IComponentAssociation;
var donor = association.Target.Apply(@from);
var acceptor = association.Source.Apply(to);
Expression result;
if (component != null)
{
//todo: probably should filterout expand somehow. E.g. 'foo.id' should become 'id'. Now simply not passing outer expand
result = BuildWriterBody(donor, acceptor, null);
if (result.NodeType == ExpressionType.Default && result.Type == typeof(void))
{
return(null);
}
}
else
{
PropertyInfo prop;
if (!acceptor.TryGetProperty(out prop))
{
throw new InvalidOperationException(
string.Format("Mapping from source:{0} to target:{1} marked as writable but source is not a property access expression", association.Source.Stringify(), association.Target.Stringify())
);
}
result = Expression.Assign(
acceptor,
converter == null ? donor : converter.TargetConverter.Expression.Apply(donor)
);
}
if (!(donor.Type.IsValueType || (result.NodeType == ExpressionType.Assign && ((BinaryExpression)result).Right == donor)))
{
result = Expression.IfThenElse(
donor.CreateCheckForDefault(),
Expression.Assign(acceptor, acceptor.Type.GetDefaultExpression()),
result
);
}
if (explicitProperties != null)
{
result = Expression.IfThen(
Expression.OrElse(
explicitProperties.CreateCheckForDefault(),
explicitProperties.CreateContains(Expression.Constant(association.Key, typeof(string)))
),
result
);
}
return(result);
}
private Expression BuildReaderItem(IMappingAssociation association, Expression from, ParameterExpression expands)
{
if ((association.Direction & MappingDirection.Read) != MappingDirection.Read)
{
return(null);
}
var converter = association as IConvertionAssociation;
var collection = association as ICollectionAssociation;
var component = association as IComponentAssociation;
var expandable = association as IExpandableAssociation;
Expression result;
var donor = association.Source.Apply(from);
var targetType = association.Target.ReturnType;
if (collection != null)
{
LambdaExpression selector;
//selector = new component { ... }
if (component != null)
{
var param = Expression.Parameter(collection.SourceItemType);
//todo: probably should filterout expand somehow. E.g. 'foo.id' should become 'id'. Now simply not passing outer expand
var body = BuildReaderBody(param, collection.TargetItemType, null);
selector = Expression.Lambda(body, param);
}
//selector = converter
else if (converter != null)
{
selector = converter.TargetConverter.Expression;
}
else
{
throw new InvalidOperationException();
}
// from.prop.select(selector).toarray().asenumerable()
result =
Expression.Convert(
Expression.Call(
ToArray.MakeGenericMethod(collection.TargetItemType),
Expression.Call(
Select.MakeGenericMethod(collection.SourceItemType, collection.TargetItemType),
donor,
selector
)
),
targetType
);
}
else
{
// new component { .... }
if (component != null)
{
//todo: probably should filterout expand somehow. E.g. 'foo.id' should become 'id'. Now simply not passing outer expand
result = BuildReaderBody(donor, targetType, null);
}
//-or- converter(from.prop)
else if (converter != null)
{
result = converter.SourceConverter.Expression.Apply(donor);
}
// from.prop
else
{
result = donor;
}
}
// expands.contains({key}) ? {exp} : null
if (result != null && expands != null && expandable != null && expandable.Expand)
{
result = Expression.Condition(
expands.CreateContains(Expression.Constant(association.Key, typeof(string))),
result,
targetType.GetDefaultExpression()
);
}
// from.prop != null ? null : {exp}
if (!(donor.Type.IsValueType || result == donor))
{
result = Expression.Condition(
donor.CreateCheckForDefault(),
targetType.GetDefaultExpression(),
result
);
}
return(result);
}