jellyfin-server/RSSDP/IEnumerableExtensions.cs

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using System;
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using System.Collections.Generic;
using System.Linq;
namespace Rssdp.Infrastructure
{
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internal static class IEnumerableExtensions
{
public static IEnumerable<T> SelectManyRecursive<T>(this IEnumerable<T> source, Func<T, IEnumerable<T>> selector)
{
if (source == null) throw new ArgumentNullException(nameof(source));
if (selector == null) throw new ArgumentNullException(nameof(selector));
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return !source.Any() ? source :
source.Concat(
source
.SelectMany(i => selector(i).EmptyIfNull())
.SelectManyRecursive(selector)
);
}
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public static IEnumerable<T> EmptyIfNull<T>(this IEnumerable<T> source)
{
return source ?? Enumerable.Empty<T>();
}
}
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}