internal FluentNHibernateDistributedLock Acquire()
{
var finish = DateTime.Now.Add(_timeout);
while (true)
{
_cancellationToken.ThrowIfCancellationRequested();
if (SqlUtil.WrapForTransaction(() =>
{
lock (Mutex)
{
using (var session = _storage.GetSession())
{
using (var transaction = session.BeginTransaction(IsolationLevel.Serializable))
{
var utcNow = session.Storage.UtcNow;
var count = session.CreateQuery(SqlUtil.GetCreateDistributedLockStatement())
.SetParameter(SqlUtil.ResourceParameterName, _resource)
.SetParameter(SqlUtil.ExpireAtAsLongParameterName,
utcNow.Add(_timeout).ToUnixDate())
.SetParameter(SqlUtil.NowParameterName, utcNow)
.SetParameter(SqlUtil.NowAsLongParameterName, utcNow.ToUnixDate());
if (count.ExecuteUpdate() > 0)
{
transaction.Commit();
return(true);
}
}
}
}
return(false);
}))
{
Logger.DebugFormat("Granted distributed lock for {0}", _resource);
_acquired = true;
return(this);
}
if (finish > DateTime.Now)
{
_cancellationToken.WaitHandle.WaitOne(DelayBetweenPasses);
}
else
{
throw new FluentNHibernateDistributedLockException("cannot acquire lock");
}
}
}
private bool CreateLockRow()
{
return(SqlUtil.WrapForDeadlock(() =>
{
lock (Mutex)
{
using (var session = _storage.GetSession())
{
using (var transaction = session.BeginTransaction(IsolationLevel.Serializable))
{
var lockResourceParams = new LockResourceParams(session, _resource, _timeout);
var query = session.CreateQuery(SqlUtil.GetCreateDistributedLockStatement())
.SetParameter(SqlUtil.ResourceParameterName, lockResourceParams.Resource)
.SetParameter(SqlUtil.ExpireAtAsLongParameterName,
lockResourceParams.ExpireAtAsLong)
.SetParameter(SqlUtil.CreatedAtParameterName, lockResourceParams.CreatedAt)
.SetParameter(SqlUtil.UtcNowAsLongParameterName, lockResourceParams.CreatedAtAsLong);
var count = query.ExecuteUpdate();
if (count == 1)
{
transaction.Commit();
if (Logger.IsDebugEnabled())
{
Logger.DebugFormat("Created distributed lock for {0}",
JsonConvert.SerializeObject(lockResourceParams));
}
return true;
}
}
}
return false;
}
}, _options));
}
