public virtual SessionToken CheckForUpdate(string currentVersion)
{
UninterruptableMonitor.Enter(syncLock);
try
{
EnsureOpen();
if (currentRevision is null)
{
return(null); // no published revisions yet
}
if (currentVersion != null && currentRevision.Revision.CompareTo(currentVersion) <= 0)
{
return(null); // currentVersion is newer or equal to latest published revision
}
// currentVersion is either null or older than latest published revision
currentRevision.IncRef();
string sessionID = sessionToken.IncrementAndGet().ToString();
SessionToken token = new SessionToken(sessionID, currentRevision.Revision);
sessions[sessionID] = new ReplicationSession(token, currentRevision);
return(token);
}
finally
{
UninterruptableMonitor.Exit(syncLock);
}
}
public virtual Stream ObtainFile(string sessionId, string source, string fileName)
{
lock (padlock)
{
EnsureOpen();
ReplicationSession session = sessions[sessionId];
if (session != null && session.IsExpired(ExpirationThreshold))
{
ReleaseSession(sessionId);
session = null;
}
// session either previously expired, or we just expired it
if (session == null)
{
throw new SessionExpiredException(string.Format("session ({0}) expired while obtaining file: source={1} file={2}", sessionId, source, fileName));
}
sessions[sessionId].MarkAccessed();
return(session.Revision.Revision.Open(source, fileName));
}
}
