private void OnCmd_CanvasUnsubscribe(JObject payload)
{
//Stop if we're already busy
if (subscribing)
{
return;
}
subscribing = true;
//If we have a set canvas, unsubscribe
if (canvas != null)
{
canvas.Unsubscribe(this).GetAwaiter().GetResult();
canvas = null;
}
subscribing = false;
}
/// <summary>
/// Gets a canvas from the database or from memory
/// </summary>
/// <param name="id"></param>
/// <returns></returns>
public static async Task <LoadedCanvas> GetCanvas(ObjectId id)
{
LoadedCanvas canvas;
lock (Program.canvases)
{
//Check if we are loaded into memory
if (Program.canvases.ContainsKey(id.ToString()))
{
canvas = Program.canvases[id.ToString()];
}
else
{
//Create canvas object
canvas = new LoadedCanvas
{
canvas_data = new MemoryStream(),
data_unsaved = true,
subscribers = new List <UserConnection>(),
resume_tokens = new Dictionary <string, int>(),
canvas_id = id,
save_timer = new Timer(60 * 1000)
};
//Add
Program.canvases.Add(id.ToString(), canvas);
//Compute
canvas.load_task = canvas.InternalGetCanvas(id);
}
}
//Wait for completion
bool loaded = await canvas.load_task;
//If loaded, return canvas
if (!loaded)
{
return(null);
}
else
{
return(canvas);
}
}
/// <summary>
/// Switches the current active canvas
/// </summary>
/// <returns></returns>
public async Task <bool> ChangeSubscribedCanvas(string id)
{
//Stop if we're already busy
if (subscribing)
{
return(false);
}
subscribing = true;
//If we have a set canvas, unsubscribe
if (canvas != null)
{
await canvas.Unsubscribe(this);
canvas = null;
}
//Now, get the canvas
if (!ObjectId.TryParse(id, out ObjectId canvas_id))
{
subscribing = false;
return(false);
}
canvas = await LoadedCanvas.GetCanvas(canvas_id);
if (canvas == null)
{
subscribing = false;
return(false);
}
//Subscribe to this canvas
await canvas.Subscribe(this);
subscribing = false;
return(true);
}