private void Remove(MulticastEnumerator inner)
{
for (; ;)
{
var a = Volatile.Read(ref _enumerators);
var n = a.Length;
if (n == 0)
{
return;
}
var j = Array.IndexOf(a, inner);
if (j < 0)
{
return;
}
MulticastEnumerator[] b;
if (n == 1)
{
b = Empty;
}
else
{
b = new MulticastEnumerator[n - 1];
Array.Copy(a, 0, b, 0, j);
Array.Copy(a, j + 1, b, j, n - j - 1);
}
if (Interlocked.CompareExchange(ref _enumerators, b, a) == a)
{
return;
}
}
}
/// <summary>
/// Returns an <see cref="IAsyncEnumerator{T}"/> representing an active asynchronous sequence.
/// </summary>
/// <returns>The active asynchronous sequence to be consumed.</returns>
public IAsyncEnumerator <T> GetAsyncEnumerator()
{
var en = new MulticastEnumerator(this);
if (Add(en))
{
return(en);
}
if (_error != null)
{
return(new Error <T> .ErrorEnumerator(_error));
}
return(new Empty <T>());
}
/// <summary>
/// Returns an <see cref="IAsyncEnumerator{T}"/> representing an active asynchronous sequence.
/// </summary>
/// <returns>The active asynchronous sequence to be consumed.</returns>
public IAsyncEnumerator <T> GetAsyncEnumerator(CancellationToken cancellationToken)
{
var en = new MulticastEnumerator(this);
if (Add(en))
{
// FIXME what about the registration???
cancellationToken.Register(v => (v as MulticastEnumerator)?.Cancel(), en);
return(en);
}
if (_error != null)
{
return(new Error <T> .ErrorEnumerator(_error));
}
return(new Empty <T>());
}
private bool Add(MulticastEnumerator inner)
{
for (; ;)
{
var a = Volatile.Read(ref _enumerators);
if (a == Terminated)
{
return(false);
}
var n = a.Length;
var b = new MulticastEnumerator[n + 1];
Array.Copy(a, 0, b, 0, n);
b[n] = inner;
if (Interlocked.CompareExchange(ref _enumerators, b, a) == a)
{
return(true);
}
}
}
