public async Task <bool> MoveNext(CancellationToken cancellationToken)
{
if (_dataReader == null)
{
await _relationalQueryContext.Connection.OpenAsync(cancellationToken);
try
{
var relationalCommand
= _shaperCommandContext
.GetRelationalCommand(_relationalQueryContext.ParameterValues, _relationalQueryContext);
_dataReader
= await relationalCommand.ExecuteReaderAsync(
_relationalQueryContext.Connection,
_relationalQueryContext.ParameterValues,
_relationalQueryContext.CommandLogger,
cancellationToken);
}
catch
{
// If failure happens creating the data reader, then it won't be available to
// handle closing the connection, so do it explicitly here to preserve ref counting.
_relationalQueryContext.Connection.Close();
throw;
}
_dbDataReader = _dataReader.DbDataReader;
}
using (await _relationalQueryContext.ConcurrencyDetector
.EnterCriticalSectionAsync(cancellationToken))
{
bool hasNext;
try
{
hasNext = await _dbDataReader.ReadAsync(cancellationToken);
}
catch (Exception exception)
{
_logger.QueryIterationFailed(_contextType, exception);
throw;
}
Current
= hasNext
? _materializer(_dbDataReader, _relationalQueryContext.Context)
: default;
return(hasNext);
}
}
// ReSharper disable once InconsistentNaming
private static IEnumerable <TEntity> _FastQuery <TEntity>(
RelationalQueryContext relationalQueryContext,
ShaperCommandContext shaperCommandContext,
Func <DbDataReader, DbContext, TEntity> materializer,
Type contextType,
IDiagnosticsLogger <DbLoggerCategory.Query> logger)
{
relationalQueryContext.Connection.Open();
RelationalDataReader dataReader;
try
{
var relationalCommand
= shaperCommandContext
.GetRelationalCommand(relationalQueryContext.ParameterValues, relationalQueryContext);
dataReader
= relationalCommand.ExecuteReader(
relationalQueryContext.Connection,
relationalQueryContext.ParameterValues,
relationalQueryContext.CommandLogger);
}
catch
{
// If failure happens creating the data reader, then it won't be available to
// handle closing the connection, so do it explicitly here to preserve ref counting.
relationalQueryContext.Connection.Close();
throw;
}
var dbDataReader = dataReader.DbDataReader;
try
{
using (dataReader)
{
using (relationalQueryContext.ConcurrencyDetector.EnterCriticalSection()) // TODO: IDisposable box?
{
while (true)
{
bool hasNext;
try
{
hasNext = dataReader.Read();
}
catch (Exception exception)
{
logger.QueryIterationFailed(contextType, exception);
throw;
}
if (hasNext)
{
yield return(materializer(dbDataReader, relationalQueryContext.Context));
}
else
{
yield break;
}
}
}
}
}
finally
{
relationalQueryContext.Connection?.Close();
relationalQueryContext.Dispose();
}
}