private static void WriteSessionRecoveryFeatureRequest(TdsPackageWriter writer, SessionData reconnectData)
{
var(_, initialLength, currentLength, writeState) = SessionRecoveryFeatureRequestLengths(reconnectData);
writer.WriteByte(TdsEnums.FEATUREEXT_SRECOVERY);
if (reconnectData == null)
{
writer.WriteInt32(0);
}
else
{
writer.WriteInt32(8 + initialLength + currentLength); // length of data w/o total length (initial + current + 2 * sizeof(DWORD))
writer.WriteInt32(initialLength);
writer.WriteByteLenString(reconnectData.InitialDatabase);
writer.WriteCollation(reconnectData.InitialCollation);
writer.WriteByteLenString(reconnectData.InitialLanguage);
for (var i = 0; i < SessionData.MaxNumberOfSessionStates; i++)
{
if (reconnectData.InitialState[i] != null)
{
writer.WriteByte((byte)i);
if (reconnectData.InitialState[i].Length < 0xFF)
{
writer.WriteByte((byte)reconnectData.InitialState[i].Length);
}
else
{
writer.WriteByte(0xFF);
writer.WriteInt32(reconnectData.InitialState[i].Length);
}
writer.WriteByteArray(reconnectData.InitialState[i]);
}
}
writer.WriteInt32(currentLength);
writer.WriteByteLenString(reconnectData.Database != reconnectData.InitialDatabase ? reconnectData.Database : null);
writer.WriteCollation(SqlCollations.AreSame(reconnectData.InitialCollation, reconnectData.Collation) ? null : reconnectData.Collation);
writer.WriteByteLenString(reconnectData.Language != reconnectData.InitialLanguage ? reconnectData.Language : null);
for (var i = 0; i < SessionData.MaxNumberOfSessionStates; i++)
{
if (writeState[i])
{
writer.WriteByte((byte)i);
if (reconnectData.Delta[i].DataLength < 0xFF)
{
writer.WriteByte((byte)reconnectData.Delta[i].DataLength);
}
else
{
writer.WriteByte(0xFF);
writer.WriteInt32(reconnectData.Delta[i].DataLength);
}
writer.WriteByteArray(reconnectData.Delta[i].Data);
}
}
}
}
private static (int totalLength, int initialLength, int currentLength, bool[] writeState) SessionRecoveryFeatureRequestLengths(SessionData reconnectData)
{
var totalLength = 1;
var initialLength = 0; // sizeof(DWORD) - length itself
var currentLength = 0; // sizeof(DWORD) - length itself
var writeState = new bool[SessionData.MaxNumberOfSessionStates];
if (reconnectData == null)
{
totalLength += 4;
}
else
{
Debug.Assert(reconnectData.UnrecoverableStatesCount == 0, "Unrecoverable state count should be 0");
initialLength += 1 + 2 * NullAwareStringLength(reconnectData.InitialDatabase);
initialLength += 1 + 2 * NullAwareStringLength(reconnectData.InitialLanguage);
initialLength += reconnectData.InitialCollation == null ? 1 : 6;
for (var i = 0; i < SessionData.MaxNumberOfSessionStates; i++)
{
if (reconnectData.InitialState[i] != null)
{
initialLength += 1 /* StateId*/ + StateValueLength(reconnectData.InitialState[i].Length);
}
}
currentLength += 1 + 2 * (reconnectData.InitialDatabase == reconnectData.Database ? 0 : NullAwareStringLength(reconnectData.Database));
currentLength += 1 + 2 * (reconnectData.InitialLanguage == reconnectData.Language ? 0 : NullAwareStringLength(reconnectData.Language));
currentLength += reconnectData.Collation != null && !SqlCollations.AreSame(reconnectData.Collation, reconnectData.InitialCollation) ? 6 : 1;
for (var i = 0; i < SessionData.MaxNumberOfSessionStates; i++)
{
if (reconnectData.Delta[i] != null)
{
Debug.Assert(reconnectData.Delta[i].Recoverable, "State should be recoverable");
writeState[i] = true;
if (reconnectData.InitialState[i] != null && reconnectData.InitialState[i].Length == reconnectData.Delta[i].DataLength)
{
writeState[i] = false;
for (var j = 0; j < reconnectData.Delta[i].DataLength; j++)
{
if (reconnectData.InitialState[i][j] != reconnectData.Delta[i].Data[j])
{
writeState[i] = true;
break;
}
}
}
if (writeState[i])
{
currentLength += 1 /* StateId*/ + StateValueLength(reconnectData.Delta[i].DataLength);
}
}
}
totalLength += initialLength + currentLength + 12 /* length fields (initial, current, total) */;
}
return(totalLength, initialLength, currentLength, writeState);
}