/// <summary>
/// Filter the fields info to preserve only the fields that are marked by MarshalOrder,
/// and sort the filtered fields.
/// </summary>
/// <param name="declaredFieldsInfo">Fields to be filtered and sorted.</param>
/// <returns>Filtered and sorted fields info.</returns>
protected static FieldInfo[] FilterAndSortFields(FieldInfo[] declaredFieldsInfo)
{
List <FieldInfo> fieldsList = declaredFieldsInfo.ToList();
List <int> toRemoveIndices = new List <int>();
for (int i = 0; i < fieldsList.Count; i++)
{
object[] fieldAttributes = fieldsList[i].GetCustomAttributes(typeof(MarshalOrderAttribute), true);
if (fieldAttributes.Length != 1)
{
toRemoveIndices.Add(i);
if (fieldAttributes.Length > 1)
{
// Prohibit the case where there are multiple MarshalOrder attributes.
throw new InvalidMarshallableException(string.Format("MarshalOrder marked {0} times.", fieldAttributes.Length));
}
continue;
}
}
foreach (int index in toRemoveIndices.OrderByDescending(v => v))
{
// Fields that have not been marked with MarshalOrder attribute
// will not be marshalled from or unmarshalled to.
fieldsList.RemoveAt(index);
}
declaredFieldsInfo = fieldsList.ToArray();
FieldComparer fieldComparer = new FieldComparer();
Array.Sort(declaredFieldsInfo, (x, y) => { return(fieldComparer.Compare(x, y)); });
// Make sure there are no duplicate attributes.
int lastOrder = -1;
for (int i = 0; i < declaredFieldsInfo.Length; i++)
{
MarshalOrderAttribute attribute = (MarshalOrderAttribute)declaredFieldsInfo[i]
.GetCustomAttributes(typeof(MarshalOrderAttribute), true)[0];
if (i == 0)
{
lastOrder = attribute.Order;
}
else if (attribute.Order == lastOrder)
{
throw new InvalidMarshallableException(string.Format("Field {0} has a conflicting ID {1}.", declaredFieldsInfo[i].Name, lastOrder));
}
}
return(fieldsList.ToArray());
}
public int Compare(FieldInfo x, FieldInfo y)
{
object[] xAttributes = x.GetCustomAttributes(typeof(MarshalOrderAttribute), true);
object[] yAttributes = y.GetCustomAttributes(typeof(MarshalOrderAttribute), true);
if (xAttributes.Length < 1)
{
throw new ArgumentException(
string.Format("The field {0} has {1} MarshalOrderAttribute.", x.Name, xAttributes.Length));
}
if (yAttributes.Length < 1)
{
throw new ArgumentException(
string.Format("The field {0} has {1} MarshalOrderAttribute.", y.Name, yAttributes.Length));
}
MarshalOrderAttribute xAttribute = (MarshalOrderAttribute)xAttributes[0];
MarshalOrderAttribute yAttribute = (MarshalOrderAttribute)yAttributes[0];
return(xAttribute.Order.CompareTo(yAttribute.Order));
}