///<summary>
/// Serialize an <see cref="System.Data.IDataReader"/> to a binary stream using protocol-buffers.
///</summary>
///<param name="stream">The <see cref="System.IO.Stream"/> to write to.</param>
///<param name="reader">The <see cref="System.Data.IDataReader"/>who's contents to serialize.</param>
///<param name="options"><see cref="ProtoDataWriterOptions"/> specifying any custom serialization options.</param>
public void Serialize(Stream stream, IDataReader reader, ProtoDataWriterOptions options)
{
if (stream == null) throw new ArgumentNullException("stream");
if (reader == null) throw new ArgumentNullException("reader");
// Null options are permitted to be passed in.
options = options ?? new ProtoDataWriterOptions();
// For a (minor) performance improvement, Serialize() has been left
// as a single long method with functions manually inlined.
var resultIndex = 0;
using (var writer = new ProtoWriter(stream, null, null))
{
do
{
// This is the underlying protocol buffers structure we use:
//
// <1 StartGroup> each DataTable
// <SubItem>
// <2 StartGroup> each DataColumn
// <SubItem>
// <1 String> Column Name
// <2 Variant> Column ProtoDataType (enum casted to int)
// </SubItem>
// <3 StartGroup> each DataRow
// <SubItem>
// <(# Column Index) (corresponding type)> Field Value
// </SubItem>
// </SubItem>
//
// NB if Field Value is a DataTable, the whole DataTable is
// write the table
ProtoWriter.WriteFieldHeader(1, WireType.StartGroup, writer);
var resultToken = ProtoWriter.StartSubItem(resultIndex, writer);
var columns = new ProtoDataColumnFactory().GetColumns(reader, options);
new HeaderWriter(writer).WriteHeader(columns);
var rowWriter = new RowWriter(writer, columns, options);
// write the rows
while (reader.Read())
rowWriter.WriteRow(reader);
ProtoWriter.EndSubItem(resultToken, writer);
resultIndex++;
} while (reader.NextResult());
}
}
private void WriteHeaderIfRequired()
{
if (isHeaderWritten)
return;
ProtoWriter.WriteFieldHeader(1, WireType.StartGroup, writer);
currentResultToken = ProtoWriter.StartSubItem(resultIndex, writer);
var columns = columnFactory.GetColumns(reader, options);
new HeaderWriter(writer).WriteHeader(columns);
rowWriter = new RowWriter(writer, columns, options);
isHeaderWritten = true;
}
