public string GetData(StreamData stream, int start, int count = -1)
{
lock (stream.Lock)
{
if (start < 0)
{
throw new InvalidOperationException("Start less than zero!");
}
//I don't care what the inputs are, if the stream is empty, you can have it
if (stream.Data.Length == 0)
{
return("");
}
if (start >= stream.Data.Length)
{
throw new InvalidOperationException($"Start beyond end of data: {stream.Data.Length}!");
}
if (count < 0 || count > stream.Data.Length - start)
{
count = stream.Data.Length - start;
}
return(stream.Data.ToString(start, count));
}
}
/// <summary>
/// Get an existing stream from memory. If it's not in memory, check disk. If it's not on disk, create a new one.
/// In any case, at the end of this call, a stream is guaranteed to be in memory.
/// </summary>
/// <param name="name"></param>
/// <returns></returns>
public StreamData GetStream(string name)
{
//Don't let ANYBODY else mess with the dictionary while we're doing it!
lock (Lock)
{
if (!Streams.ContainsKey(name))
{
//Look for the stream in permament storage.
var existing = LoadStream(name);
//Oops it didn't exist, set to a new one
if (existing == null)
{
logger.LogInformation($"Creating new room {name}");
existing = new StreamData();
}
else
{
//Just log that it was found
logger.LogInformation($"Reviving dead room {name}");
}
Streams.Add(name, existing);
}
//NOTE: because we don't get rid of readonly key associations, we ASSUME that if
//we have an existing stream, there IS a readonly key for it!
return(Streams[name]);
}
}
protected void SaveStream(string name, StreamData s, bool forceEmpty = false)
{
if (!Directory.Exists(Config.StoreLocation))
{
Directory.CreateDirectory(Config.StoreLocation);
}
//Don't save empty rooms (unless we're forced to!)
if (s.Data.Length > 0 || forceEmpty)
{
File.WriteAllText(Path.Combine(Config.StoreLocation, name), s.Data.ToString());
}
s.SaveDate = DateTime.Now;
}
public async Task <ReadyData> GetDataWhenReady(StreamData stream, int start, int count = -1)
{
//JUST IN CASE we need it later (can't make it in the lock section, needed outside!)
bool completed = false;
StreamListener listener = null;
ReadyData result = new ReadyData();
lock (stream.Lock)
{
if (start < stream.Data.Length)
{
//No waiting! We're already done! The stream can never get smaller!
completed = true;
}
else
{
//Oh, waiting... we're a new listener so add it!
listener = new StreamListener();
listener.Waiter = Task.Run(() => completed = stream.Signal.WaitOne(Config.ListenTimeout));
stream.Listeners.Add(listener);
}
}
//Don't need to listen if there's no listener!
if (listener != null)
{
//CANNOT wait in the lock! We're just waiting to see if we get data. If we DOOOO, "completed" will be true!
try
{
await listener.Waiter;
}
finally
{
//We're done. Doesn't matter what happened, whether it finished or we threw an exception,
//we are NO LONGER listening!
result.SignalData = listener.SignalData; //this might be nothing
stream.Listeners.Remove(listener);
}
}
if (completed)
{
result.Data = GetData(stream, start, count);
}
return(result);
}
public void AddData(StreamData stream, string data)
{
lock (stream.Lock)
{
if (data.Length == 0)
{
throw new InvalidOperationException("Can't add 0 length data!");
}
if (data.Length > Config.SingleDataLimit)
{
throw new InvalidOperationException($"Too much data at once!: {Config.SingleDataLimit}");
}
//Don't allow data additions that would allow the limit to go beyond thingy!
if (stream.Data.Length >= Config.StreamDataLimit)
{
throw new InvalidOperationException($"Stream at data limit: {Config.StreamDataLimit}");
}
stream.Data.Append(data);
stream.UpdateDate = DateTime.Now;
var signalData = new SignalData()
{
ListenersBeforeSignal = stream.Listeners.Count
};
//Set the signal data before signalling so they have "communication" from us. NOT SAFE
//since someone could... you know, add a listener... or could they? We hold the lock for
//the stream and you can't add a listener without the lock! So probably safe...
stream.Listeners.ForEach(x => x.SignalData = signalData);
//Set the signal so all the listeners know they have data!
stream.Signal.Set();
try
{
var signalStart = DateTime.Now;
//Wait for OUR listeners to clear out! Notice that the listener wait and removal is NOT
//in a lock: this allows US to hold the lock (since it's probably safer...? we're doing the signalling).
while (stream.Listeners.Count > 0)
{
System.Threading.Thread.Sleep(Config.SignalWaitInterval);
if (DateTime.Now - signalStart > Config.SignalTimeout)
{
logger.LogWarning("Timed out while waiting for listeners to process signal!");
break;
}
}
}
finally
{
//ALWAYS get rid of listeners and reset the signal! we don't want to be left in an unknown state!
stream.Listeners.Clear(); //This might be dangerous? IDK, we don't want to wait forever!
stream.Signal.Reset();
}
}
}
