private IBsonSerializer BuildProjectedSerializer(ProjectionMapping mapping)
{
// We are building a serializer specifically for a projected type based
// on serialization information collected from other serializers.
// We cannot cache this in the serializer registry because the compiler reuses
// the same anonymous type definition in different contexts as long as they
// are structurally equatable. As such, it might be that two different queries
// projecting the same shape might need to be deserialized differently.
var classMap = BuildClassMap(mapping.Expression.Type, mapping);
var mappedParameters = mapping.Members
.Where(x => x.Parameter != null)
.OrderBy(x => x.Parameter.Position)
.Select(x => x.Member)
.ToList();
if (mappedParameters.Count > 0)
{
classMap.MapConstructor(mapping.Constructor)
.SetArguments(mappedParameters);
}
var serializerType = typeof(BsonClassMapSerializer <>).MakeGenericType(mapping.Expression.Type);
return((IBsonSerializer)Activator.CreateInstance(serializerType, classMap.Freeze()));
}
private BsonClassMap BuildClassMap(Type type, ProjectionMapping mapping)
{
if (type == null || type == typeof(object))
{
return(null);
}
var baseClassMap = BuildClassMap(type.GetTypeInfo().BaseType, mapping);
if (baseClassMap != null)
{
baseClassMap.Freeze();
}
var classMap = new BsonClassMap(type, baseClassMap);
foreach (var memberMapping in mapping.Members.Where(x => x.Member.DeclaringType == type))
{
var serializationExpression = memberMapping.Expression as SerializationExpression;
if (serializationExpression == null)
{
var serializer = Build(memberMapping.Expression);
serializationExpression = new FieldExpression(
memberMapping.Member.Name,
serializer,
memberMapping.Expression);
}
var memberMap = classMap.MapMember(memberMapping.Member)
.SetSerializer(serializationExpression.Serializer)
.SetElementName(memberMapping.Member.Name);
if (classMap.IdMemberMap == null && serializationExpression is GroupingKeyExpression)
{
classMap.SetIdMember(memberMap);
}
}
return(classMap);
}