void Delete(IDbConnection connection, DeleteAnnouncement request)
{
var subscriber = connection.GetById <Subscriber>(request.SubscriberId);
var announcement = connection.First(NextAnnouncement.make(connection, subscriber));
if (announcement.Id != request.AnnouncementId)
{
throw new ArgumentException("Invalid announcement");
}
connection.UpdateOnly(new Subscriber {
LastAnnouncementId = announcement.Id
},
subscription => new { subscription.LastAnnouncementId },
subscription => subscription.Id == subscriber.Id);
Propagators.ScheduleTopicOperation(request.TopicName, () => Propagate(request));
}
Announcement ReadFromDb(IDbConnection connection, Subscriber subscriber, ReadAnnouncement request)
{
var topicLock = Locks.TakeTopicLock(request.TopicName);
lock (topicLock)
{
var query = NextAnnouncement.make(connection, subscriber);
var announcement = connection.FirstOrDefault(query);
while (announcement == null)
{
Monitor.Wait(topicLock);
announcement = connection.FirstOrDefault(query);
}
return(announcement);
}
}