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29 lines
547 B
29 lines
547 B
using System.Collections;
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namespace Connected.Expressions.Collections;
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internal class EnumerateOnce<T> : IEnumerable<T>, IEnumerable
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{
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private IEnumerable<T>? _enumerable;
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public EnumerateOnce(IEnumerable<T> enumerable)
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{
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_enumerable = enumerable;
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}
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public IEnumerator<T> GetEnumerator()
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{
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var en = Interlocked.Exchange(ref _enumerable, null);
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if (en is not null)
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return en.GetEnumerator();
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throw new Exception("Enumerated more than once.");
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}
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IEnumerator IEnumerable.GetEnumerator()
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{
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return GetEnumerator();
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}
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}
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