/**
* We want to protect against infinite recursion when the schema is recursive. We look into a thread local
* to see if we have been into this if so, we execute the bypass function otherwise we execute the main function.
* Before executing the main function, we ensure that we create a marker so that if we come back here recursively
* we can detect it.
*
* The infinite loop happens in ToString(), Equals() and GetHashCode() methods.
* Though it does not happen for CanRead() because of the current implemenation of UnionSchema's can read,
* it could potenitally happen.
* We do a linear seach for the marker as we don't expect the list to be very long.
*/
private T Protect <T>(Func <T> bypass, Func <T> main, RecordSchema that)
{
if (seen == null)
{
seen = new List <RecordSchemaPair>();
}
else if (seen.FirstOrDefault((rs => rs.first == this && rs.second == that)) != null)
{
return(bypass());
}
var p = new RecordSchemaPair(this, that);
seen.Add(p);
try
{
return(main());
}
finally
{
seen.Remove(p);
}
}
public RecordSchemaPair(RecordSchema first, RecordSchema second)
{
this.first = first;
this.second = second;
}
