public Task GetModelDataAsync(string name, ModelDataDelegate callback)
{
name = Path.GetFileNameWithoutExtension(name);
Task t = null;
if (_modelData.ContainsKey(name))
{
callback(new ModelData()
{
Data = _modelData[name], Name = name
});
}
else
{
t = Task.Factory.StartNew(() => Download(name, callback, t));
}
return(t);
}
private void Download(string name, ModelDataDelegate callback, Task task)
{
Task conflictingTask = null;
lock (_tasks)
{
if (!_tasks.ContainsKey(name))
{
_tasks.Add(name, task);
}
else
{
if (_tasks.ContainsKey(name) && _tasks[name].Id != task.Id)
{
conflictingTask = _tasks[name];
}
}
}
if (conflictingTask != null)
{
Debug.WriteLine("Waiting for other task to finish.");
if (!conflictingTask.IsCompleted)
{
conflictingTask.Wait();
}
}
var model = Path.Combine(_modelPath, Path.GetFileNameWithoutExtension(name) + ".zip");
if (File.Exists(model))
{
Debug.WriteLine("Reading and unzipping model from file system.");
var zip = ZipStorer.Open(model, FileAccess.Read);
var dir = zip.ReadCentralDir();
if (dir.Count == 0)
{
lock (_tasks)
{
_tasks.Remove(name);
}
callback(new ModelData
{
Data = string.Empty, Exception = new Exception("No such model found."), Name = name
});
}
using (var mem = new MemoryStream())
{
zip.ExtractFile(dir[0], mem);
zip.Close();
mem.Position = 0;
using (var sr = new StreamReader(mem))
{
var data = sr.ReadToEnd();
lock (_tasks)
{
_tasks.Remove(name);
}
if (!_modelData.ContainsKey(name))
{
_modelData.Add(name, data);
}
callback(new ModelData {
Data = data, Name = name
});
}
}
//task.Dispose();
return;
}
Debug.WriteLine("Downloading model from internet.");
using (var webClient = new WebClient())
{
try
{
webClient.DownloadFile(
Path.Combine(_remoteModelPath,
Path.GetFileNameWithoutExtension(name) + ".zip"), model);
// recurse to read the file which was saved to harddisk.
lock (_tasks)
{
_tasks.Remove(name);
}
Download(name, callback, task);
}
catch (Exception ex)
{
lock (_tasks)
{
_tasks.Remove(name);
}
callback(new ModelData {
Name = name, Data = string.Empty, Exception = ex
});
}
}
//task.Dispose();
}
