internal T Read <T>(NpgsqlBuffer buf, int len, FieldDescription fieldDescription = null)
{
T result;
var asSimpleReader = this as ISimpleTypeReader <T>;
if (asSimpleReader != null)
{
buf.Ensure(len);
result = asSimpleReader.Read(buf, len, fieldDescription);
}
else
{
var asChunkingReader = this as IChunkingTypeReader <T>;
if (asChunkingReader == null)
{
if (fieldDescription == null)
{
throw new InvalidCastException("Can't cast database type to " + typeof(T).Name);
}
throw new InvalidCastException(String.Format("Can't cast database type {0} to {1}", fieldDescription.Handler.PgName, typeof(T).Name));
}
asChunkingReader.PrepareRead(buf, len, fieldDescription);
while (!asChunkingReader.Read(out result))
{
buf.ReadMore();
}
}
return(result);
}
public override int Read(byte[] buffer, int offset, int count)
{
CheckDisposed();
if (!CanRead)
{
throw new InvalidOperationException("Stream not open for reading");
}
if (_isConsumed)
{
return(0);
}
if (_leftToReadInDataMsg == 0)
{
// We've consumed the current DataMessage (or haven't yet received the first),
// read the next message
var msg = _connector.ReadSingleMessage();
switch (msg.Code)
{
case BackendMessageCode.CopyData:
_leftToReadInDataMsg = ((CopyDataMessage)msg).Length;
break;
case BackendMessageCode.CopyDone:
_connector.ReadExpecting <CommandCompleteMessage>();
_connector.ReadExpecting <ReadyForQueryMessage>();
_isConsumed = true;
return(0);
default:
throw _connector.UnexpectedMessageReceived(msg.Code);
}
}
Contract.Assume(_leftToReadInDataMsg > 0);
// If our buffer is empty, read in more. Otherwise return whatever is there, even if the
// user asked for more (normal socket behavior)
if (_buf.ReadBytesLeft == 0)
{
_buf.ReadMore();
}
Contract.Assert(_buf.ReadBytesLeft > 0);
var maxCount = Math.Min(_buf.ReadBytesLeft, _leftToReadInDataMsg);
if (count > maxCount)
{
count = maxCount;
}
_leftToReadInDataMsg -= count;
_buf.ReadBytes(buffer, offset, count);
return(count);
}
