public async ValueTask <bool> Drain(ReplayEnumerator consumer)
{
for (; ;)
{
var d = _done;
var s = _size;
var index = consumer.Index;
if (d && s == index)
{
if (_error != null)
{
throw _error;
}
return(false);
}
if (index != s)
{
consumer.Current = _values[index];
consumer.Index = index + 1;
return(true);
}
await ResumeHelper.Await(ref consumer.Resume);
ResumeHelper.Clear(ref consumer.Resume);
}
}
private void Remove(ReplayEnumerator 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;
}
ReplayEnumerator[] b;
if (n == 1)
{
b = Empty;
}
else
{
b = new ReplayEnumerator[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 ReplayEnumerator(this);
Add(en);
return(en);
}
/// <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 ReplayEnumerator(this);
Add(en);
// FIXME what about the registration???
cancellationToken.Register(v => (v as ReplayEnumerator)?.Cancel(), en);
return(en);
}
private void Add(ReplayEnumerator inner)
{
for (; ;)
{
var a = Volatile.Read(ref _enumerators);
if (a == Terminated)
{
return;
}
var n = a.Length;
var b = new ReplayEnumerator[n + 1];
Array.Copy(a, 0, b, 0, n);
b[n] = inner;
if (Interlocked.CompareExchange(ref _enumerators, b, a) == a)
{
return;
}
}
}
