internal override DataRowMessage Load(NpgsqlBuffer buf)
{
buf.Ensure(sizeof(short));
NumColumns = buf.ReadInt16();
Buffer = buf;
Column = -1;
ColumnLen = -1;
PosInColumn = 0;
return this;
}
/// <summary>
/// Starts reading a single row, must be invoked before reading any columns.
/// </summary>
/// <returns>
/// The number of columns in the row. -1 if there are no further rows.
/// Note: This will currently be the same value for all rows, but this may change in the future.
/// </returns>
public int StartRow()
{
CheckDisposed();
if (_isConsumed)
{
return(-1);
}
// The very first row (i.e. _column == -1) is included in the header's CopyData message.
// Otherwise we need to read in a new CopyData row (the docs specify that there's a CopyData
// message per row).
if (_column == NumColumns)
{
_leftToReadInDataMsg = _connector.ReadExpecting <CopyDataMessage>().Length;
}
else if (_column != -1)
{
throw new InvalidOperationException("Already in the middle of a row");
}
_buf.Ensure(2);
_leftToReadInDataMsg -= 2;
var numColumns = _buf.ReadInt16();
if (numColumns == -1)
{
Contract.Assume(_leftToReadInDataMsg == 0);
_connector.ReadExpecting <CopyDoneMessage>();
_connector.ReadExpecting <CommandCompleteMessage>();
_connector.ReadExpecting <ReadyForQueryMessage>();
_column = -1;
_isConsumed = true;
return(-1);
}
Contract.Assume(numColumns == NumColumns);
_column = 0;
return(NumColumns);
}