/// <summary>
/// Creates a NDataReader from a <see cref="DbDataReader" />
/// </summary>
/// <param name="reader">The <see cref="DbDataReader" /> to get the records from the Database.</param>
/// <param name="isMidstream"><see langword="true" /> if we are loading the <see cref="DbDataReader" /> in the middle of reading it.</param>
/// <remarks>
/// NHibernate attempts to not have to read the contents of an <see cref="DbDataReader"/> into memory until it absolutely
/// has to. What that means is that it might have processed some records from the <see cref="DbDataReader"/> and will
/// pick up the <see cref="DbDataReader"/> midstream so that the underlying <see cref="DbDataReader"/> can be closed
/// so a new one can be opened.
/// </remarks>
public static NDataReader Create(DbDataReader reader, bool isMidstream)
{
var dataReader = new NDataReader();
var resultList = new List <NResult>(2);
try
{
// if we are in midstream of processing a DataReader then we are already
// positioned on the first row (index=0)
if (isMidstream)
{
dataReader.currentRowIndex = 0;
}
// there will be atleast one result
resultList.Add(NResult.Create(reader, isMidstream));
while (reader.NextResult())
{
// the second, third, nth result is not processed midstream
resultList.Add(NResult.Create(reader, false));
}
dataReader.results = resultList.ToArray();
}
catch (Exception e)
{
throw new ADOException("There was a problem converting an DbDataReader to NDataReader", e);
}
finally
{
reader.Close();
}
return(dataReader);
}
/// <summary>
/// Reads all of the contents into memory because another <see cref="DbDataReader"/>
/// needs to be opened.
/// </summary>
/// <remarks>
/// This will result in a no op if the reader is closed or is already in memory.
/// </remarks>
public void ReadIntoMemory()
{
if (_reader.IsClosed == false && _reader.GetType() != typeof(NDataReader))
{
if (log.IsDebugEnabled)
{
log.Debug("Moving DbDataReader into an NDataReader. It was converted in midstream " + _isMidstream.ToString());
}
_reader = NDataReader.Create(_reader, _isMidstream);
}
}
/// <summary>
/// Reads all of the contents into memory because another <see cref="DbDataReader"/>
/// needs to be opened.
/// </summary>
/// <param name="cancellationToken">A cancellation token that can be used to cancel the work</param>
/// <remarks>
/// This will result in a no op if the reader is closed or is already in memory.
/// </remarks>
public async Task ReadIntoMemoryAsync(CancellationToken cancellationToken)
{
cancellationToken.ThrowIfCancellationRequested();
if (_reader.IsClosed == false && _reader.GetType() != typeof(NDataReader))
{
if (log.IsDebugEnabled)
{
log.Debug("Moving DbDataReader into an NDataReader. It was converted in midstream " + _isMidstream.ToString());
}
_reader = await(NDataReader.CreateAsync(_reader, _isMidstream, cancellationToken)).ConfigureAwait(false);
}
}
/// <summary>
/// Initializes a new instance of the NHybridDataReader class.
/// </summary>
/// <param name="reader">The underlying DbDataReader to use.</param>
/// <param name="inMemory"><see langword="true" /> if the contents of the DbDataReader should be read into memory right away.</param>
public static NHybridDataReader Create(DbDataReader reader, bool inMemory)
{
var dataReader = new NHybridDataReader();
if (inMemory)
{
dataReader._reader = NDataReader.Create(reader, false);
}
else
{
dataReader._reader = reader;
}
return(dataReader);
}
/// <summary>
/// Initializes a new instance of the NHybridDataReader class.
/// </summary>
/// <param name="reader">The underlying DbDataReader to use.</param>
/// <param name="inMemory"><see langword="true" /> if the contents of the DbDataReader should be read into memory right away.</param>
/// <param name="cancellationToken">A cancellation token that can be used to cancel the work</param>
public static async Task <NHybridDataReader> CreateAsync(DbDataReader reader, bool inMemory, CancellationToken cancellationToken)
{
cancellationToken.ThrowIfCancellationRequested();
var dataReader = new NHybridDataReader();
if (inMemory)
{
dataReader._reader = await(NDataReader.CreateAsync(reader, false, cancellationToken)).ConfigureAwait(false);
}
else
{
dataReader._reader = reader;
}
return(dataReader);
}
/// <summary>
/// Creates a NDataReader from a <see cref="DbDataReader" />
/// </summary>
/// <param name="reader">The <see cref="DbDataReader" /> to get the records from the Database.</param>
/// <param name="isMidstream"><see langword="true" /> if we are loading the <see cref="DbDataReader" /> in the middle of reading it.</param>
/// <param name="cancellationToken">A cancellation token that can be used to cancel the work</param>
/// <remarks>
/// NHibernate attempts to not have to read the contents of an <see cref="DbDataReader"/> into memory until it absolutely
/// has to. What that means is that it might have processed some records from the <see cref="DbDataReader"/> and will
/// pick up the <see cref="DbDataReader"/> midstream so that the underlying <see cref="DbDataReader"/> can be closed
/// so a new one can be opened.
/// </remarks>
public static async Task <NDataReader> CreateAsync(DbDataReader reader, bool isMidstream, CancellationToken cancellationToken)
{
cancellationToken.ThrowIfCancellationRequested();
var dataReader = new NDataReader();
var resultList = new List <NResult>(2);
try
{
// if we are in midstream of processing a DataReader then we are already
// positioned on the first row (index=0)
if (isMidstream)
{
dataReader.currentRowIndex = 0;
}
// there will be atleast one result
resultList.Add(await(NResult.CreateAsync(reader, isMidstream, cancellationToken)).ConfigureAwait(false));
while (await(reader.NextResultAsync(cancellationToken)).ConfigureAwait(false))
{
// the second, third, nth result is not processed midstream
resultList.Add(await(NResult.CreateAsync(reader, false, cancellationToken)).ConfigureAwait(false));
}
dataReader.results = resultList.ToArray();
}
catch (OperationCanceledException) { throw; }
catch (Exception e)
{
throw new ADOException("There was a problem converting an DbDataReader to NDataReader", e);
}
finally
{
reader.Close();
}
return(dataReader);
}
