using System;

using System.IO;

using System.Threading.Tasks;

namespace Semmle

{

public class Asynchronous

{

private static string[] filenames = { "async.cs", "Await.ql" };

private static void Main(string[] args)

{

Task[] results = new Task[filenames.Length];

for (int i = 0; i < results.Length; i++)

results[i] = PrintContentLengthAsync(filenames[i]);

for (int i = 0; i < results.Length; i++)

results[i].Wait();

}

private static async Task PrintContentLengthAsync(string filename)

{

int length = await ContentLengthAsync(filename);

Console.WriteLine("Fetched " + length + " characters");

}

private static async Task<int> ContentLengthAsync(string filename)

{

using (StreamReader reader = File.OpenText(filename))

{

string content = await reader.ReadToEndAsync();

return content.Length;

}

}

// regression test for 'AddResumePoint' error

private static async void AsyncIterator(string filename)

{

using (StreamReader other = File.OpenText(filename))

{

using (StreamReader reader = await OpenAsync(filename))

{

string content = await reader.ReadToEndAsync();

Console.WriteLine(content.Length);

}

}

}

private static async Task<StreamReader> OpenAsync(string filename)

{

await PrintContentLengthAsync(filename);

return File.OpenText(filename);

}

private ref struct RS

{

public int GetZero() { return 0; }

}

private static int one = 1;

// Test that we can use ref locals, ref structs and unsafe blocks in async methods.

private static async Task<int> GetObjectAsync()

{

unsafe

{

// Do pointer stuff

}

RS rs;

ref int i = ref one;

var zero = rs.GetZero();

await Task.Delay(i);

return zero;

}

}

}