using System.Threading; namespace System.Reactive.Disposables { public static class Disposable { private sealed class EmptyDisposable : IDisposable { public static readonly EmptyDisposable Instance = new EmptyDisposable(); private EmptyDisposable() { } public void Dispose() { } } public static IDisposable Empty => EmptyDisposable.Instance; public static IDisposable Create(Action dispose) { if (dispose == null) throw new ArgumentNullException("dispose"); return new AnonymousDisposable(dispose); } public static IDisposable Create<TState>(TState state, Action<TState> dispose) { if (dispose == null) throw new ArgumentNullException("dispose"); return new AnonymousDisposable<TState>(state, dispose); } internal static IDisposable GetValue(ref IDisposable fieldRef) { IDisposable disposable = Volatile.Read(ref fieldRef); if (disposable != BooleanDisposable.True) return disposable; return null; } internal static IDisposable GetValueOrDefault(ref IDisposable fieldRef) { IDisposable disposable = Volatile.Read(ref fieldRef); if (disposable != BooleanDisposable.True) return disposable; return EmptyDisposable.Instance; } internal static bool SetSingle(ref IDisposable fieldRef, IDisposable value) { TrySetSingleResult num = TrySetSingle(ref fieldRef, value); if (num == TrySetSingleResult.AlreadyAssigned) throw new InvalidOperationException(Strings_Core.DISPOSABLE_ALREADY_ASSIGNED); return num == TrySetSingleResult.Success; } internal static TrySetSingleResult TrySetSingle(ref IDisposable fieldRef, IDisposable value) { IDisposable disposable = Interlocked.CompareExchange(ref fieldRef, value, null); if (disposable == null) return TrySetSingleResult.Success; if (disposable != BooleanDisposable.True) return TrySetSingleResult.AlreadyAssigned; value?.Dispose(); return TrySetSingleResult.Disposed; } internal static bool TrySetMultiple(ref IDisposable fieldRef, IDisposable value) { IDisposable disposable = Volatile.Read(ref fieldRef); while (true) { if (disposable == BooleanDisposable.True) { value?.Dispose(); return false; } IDisposable disposable2 = Interlocked.CompareExchange(ref fieldRef, value, disposable); if (disposable == disposable2) break; disposable = disposable2; } return true; } internal static bool TrySetSerial(ref IDisposable fieldRef, IDisposable value) { IDisposable disposable = Volatile.Read(ref fieldRef); while (true) { if (disposable == BooleanDisposable.True) { value?.Dispose(); return false; } IDisposable disposable2 = Interlocked.CompareExchange(ref fieldRef, value, disposable); if (disposable2 == disposable) break; disposable = disposable2; } disposable?.Dispose(); return true; } internal static bool GetIsDisposed(ref IDisposable fieldRef) { return Volatile.Read(ref fieldRef) == BooleanDisposable.True; } internal static bool TryDispose(ref IDisposable fieldRef) { IDisposable disposable = Interlocked.Exchange(ref fieldRef, BooleanDisposable.True); if (disposable == BooleanDisposable.True) return false; disposable?.Dispose(); return true; } internal static bool TryRelease<TState>(ref IDisposable fieldRef, TState state, Action<IDisposable, TState> disposeAction) { IDisposable disposable = Interlocked.Exchange(ref fieldRef, BooleanDisposable.True); if (disposable == BooleanDisposable.True) return false; disposeAction(disposable, state); return true; } } }