private FDMessageEnvelope MaybeReserveOne()
{
var qPath = FDMessageBus.GetQueuePath(_busName, _exchangeName, _queueName);
foreach (var it in _messageNames)
{
if (_taken.Contains(it))
{
continue;
}
var mmtx = FDMessageBus.GetMessageMutex(_exchangeName, _queueName, it);
if (mmtx.Open())
{
try
{
var fn = Path.Combine(qPath, it);
var fi = new FileInfo(fn);
_taken.Add(it);
if (fi.Exists)
{
using (var sr = fi.OpenText())
{
var text = sr.ReadToEnd();
var retval = JsonConvert.DeserializeObject <FDMessageEnvelope>(text,
_serializerSettings);
if (null != retval)
{
retval.Lock = mmtx;
return(retval);
}
}
}
mmtx.Release();
}
catch // not finally, because if we can open the message, control of the mutex passes
// to the caller
{
mmtx.Release();
}
}
mmtx.Dispose();
}
return(null);
}
