private Func <IDataReader, object> GetReader(IDataReader reader, int startBound, int length, bool returnNullIfFirstMissing)
{
if (length < 0)
{
length = reader.FieldCount - startBound;
}
int hash = GetColumnHash(reader, startBound, length);
if (returnNullIfFirstMissing)
{
hash *= -27;
}
// get a cheap key first: false means don't copy the values down
var key = new DeserializerKey(hash, startBound, length, returnNullIfFirstMissing, reader, false);
Func <IDataReader, object> deser;
lock (readers)
{
if (readers.TryGetValue(key, out deser))
{
return(deser);
}
}
deser = GetTypeDeserializerImpl(type, reader, startBound, length, returnNullIfFirstMissing);
// get a more expensive key: true means copy the values down so it can be used as a key later
key = new DeserializerKey(hash, startBound, length, returnNullIfFirstMissing, reader, true);
lock (readers)
{
return(readers[key] = deser);
}
}
private Func <XmlGridRowReader, object> GetDeserializer(
XmlGridRowReader reader)
{
reader.ReadRow();
if (!reader.Columns.Any())
{
throw new InvalidOperationException("No columns");
}
var key = new DeserializerKey(reader.Columns);
if (!deserializers.TryGetValue(key, out var deserializer))
{
lock (deserializers)
{
if (!deserializers.TryGetValue(key, out deserializer))
{
deserializer = CreateDeserializer(type, reader.Columns);
deserializers.Add(key, deserializer);
}
}
}
return(deserializer);
}
public bool Equals(DeserializerKey other)
{
if (hashCode != other.hashCode
|| startBound != other.startBound
|| length != other.length
|| returnNullIfFirstMissing != other.returnNullIfFirstMissing)
{
return false; // clearly different
}
for (int i = 0; i < length; i++)
{
if ((names? i] ?? reader?.GetName(startBound + i)) != (other.names? i] ?? other.reader?.GetName(startBound + i))
||
(types? i] ?? reader?.GetFieldType(startBound + i)) != (other.types? i] ?? other.reader?.GetFieldType(startBound + i))
)
{
return false; // different column name or type
}
}
return true;
}
