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@aelij /-Usage.cs
Last active Sep 5, 2017

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IAsyncEnumerable Bridge for Service Fabric Reliable Collections
class MyService : StatefulService
{
private Task<IReliableDictionary<int, string>> AccountNames => StateManager.GetOrAddAsync<IReliableDictionary<int, string>>("AccountNames");
private Task<IReliableDictionary<int, string>> AccountData => StateManager.GetOrAddAsync<IReliableDictionary<int, string>>("AccountData");
public async Task<List<Account>> SearchAccountsByNameAsync(string name)
{
using (var txn = StateManager.CreateTransaction())
{
var accountNames = await AccountNames;
var accountData = await AccountData;
var accounts = await (await accountNames.CreateLinqAsyncEnumerable(txn))
.Where(x => x.Value.IndexOf(name, StringComparison.InvariantCultureIgnoreCase) >= 0)
.SelectAsync(async x => new Account
{
Id = x.Key,
Name = x.Value,
Data = (await accountData.TryGetValueAsync(txn, x.Key)).Value
})
.ToList();
return accounts;
}
}
}
// Add NuGet package System.Interactive.Async
using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.ServiceFabric.Data.Collections;
using Fabric = Microsoft.ServiceFabric.Data;
public static class AsyncEnumerableEx
{
#region Creation
private static IAsyncEnumerable<T> Create<T>(Func<IAsyncEnumerator<T>> getEnumerator)
{
return new AnonymousAsyncEnumerable<T>(getEnumerator);
}
private class AnonymousAsyncEnumerable<T> : IAsyncEnumerable<T>
{
private readonly Func<IAsyncEnumerator<T>> _getEnumerator;
public AnonymousAsyncEnumerable(Func<IAsyncEnumerator<T>> getEnumerator)
{
_getEnumerator = getEnumerator;
}
public IAsyncEnumerator<T> GetEnumerator()
{
return _getEnumerator();
}
}
private static IAsyncEnumerator<T> Create<T>(Func<CancellationToken, Task<bool>> moveNext, Func<T> current,
Action dispose, IDisposable enumerator)
{
return Create(async ct =>
{
using (ct.Register(dispose))
{
try
{
var result = await moveNext(ct).ConfigureAwait(false);
if (!result)
{
enumerator?.Dispose();
}
return result;
}
catch
{
enumerator?.Dispose();
throw;
}
}
}, current, dispose);
}
private static IAsyncEnumerator<T> Create<T>(Func<CancellationToken, Task<bool>> moveNext, Func<T> current, Action dispose)
{
return new AnonymousAsyncEnumerator<T>(moveNext, current, dispose);
}
private class AnonymousAsyncEnumerator<T> : IAsyncEnumerator<T>
{
private readonly Func<CancellationToken, Task<bool>> _moveNext;
private readonly Func<T> _current;
private readonly Action _dispose;
private bool _disposed;
public AnonymousAsyncEnumerator(Func<CancellationToken, Task<bool>> moveNext, Func<T> current, Action dispose)
{
_moveNext = moveNext;
_current = current;
_dispose = dispose;
}
public Task<bool> MoveNext(CancellationToken cancellationToken)
{
if (_disposed)
return SpecialTasks.False;
return _moveNext(cancellationToken);
}
public T Current => _current();
public void Dispose()
{
if (!_disposed)
{
_disposed = true;
_dispose();
}
}
}
#endregion
#region Async Operators
public static IAsyncEnumerable<TResult> SelectAsync<TSource, TResult>(this IAsyncEnumerable<TSource> source, Func<TSource, Task<TResult>> selector)
{
if (source == null)
throw new ArgumentNullException(nameof(source));
if (selector == null)
throw new ArgumentNullException(nameof(selector));
return Create(() =>
{
var e = source.GetEnumerator();
var current = default(TResult);
var cts = new CancellationTokenDisposable();
var d = Disposable.Create(cts, e);
return Create(async ct =>
{
if (await e.MoveNext(cts.Token).ConfigureAwait(false))
{
current = await selector(e.Current).ConfigureAwait(false);
return true;
}
return false;
},
() => current,
d.Dispose,
e
);
});
}
public static IAsyncEnumerable<TResult> SelectAsync<TSource, TResult>(this IAsyncEnumerable<TSource> source, Func<TSource, int, Task<TResult>> selector)
{
if (source == null)
throw new ArgumentNullException(nameof(source));
if (selector == null)
throw new ArgumentNullException(nameof(selector));
return Create(() =>
{
var e = source.GetEnumerator();
var current = default(TResult);
var index = 0;
var cts = new CancellationTokenDisposable();
var d = Disposable.Create(cts, e);
return Create(async ct =>
{
if (await e.MoveNext(cts.Token).ConfigureAwait(false))
{
current = await selector(e.Current, checked(index++)).ConfigureAwait(false);
return true;
}
return false;
},
() => current,
d.Dispose,
e
);
});
}
public static IAsyncEnumerable<TSource> WhereAsync<TSource>(this IAsyncEnumerable<TSource> source, Func<TSource, Task<bool>> predicate)
{
if (source == null)
throw new ArgumentNullException(nameof(source));
if (predicate == null)
throw new ArgumentNullException(nameof(predicate));
return Create(() =>
{
var e = source.GetEnumerator();
var current = default(TSource);
var cts = new CancellationTokenDisposable();
var d = Disposable.Create(cts, e);
return Create(async ct =>
{
var b = false;
bool moveNext;
do
{
moveNext = await e.MoveNext(cts.Token).ConfigureAwait(false);
if (moveNext)
{
b = await predicate(e.Current).ConfigureAwait(false);
}
} while (!b && moveNext);
if (b)
{
current = e.Current;
return true;
}
return false;
},
() => current,
d.Dispose,
e
);
});
}
public static IAsyncEnumerable<TSource> WhereAsync<TSource>(this IAsyncEnumerable<TSource> source, Func<TSource, int, Task<bool>> predicate)
{
if (source == null)
throw new ArgumentNullException(nameof(source));
if (predicate == null)
throw new ArgumentNullException(nameof(predicate));
return Create(() =>
{
var e = source.GetEnumerator();
var index = 0;
var current = default(TSource);
var cts = new CancellationTokenDisposable();
var d = Disposable.Create(cts, e);
return Create(async ct =>
{
var b = false;
bool moveNext;
do
{
moveNext = await e.MoveNext(cts.Token).ConfigureAwait(false);
if (moveNext)
{
b = await predicate(e.Current, checked(index++)).ConfigureAwait(false);
}
} while (!b && moveNext);
if (b)
{
current = e.Current;
return true;
}
return false;
},
() => current,
d.Dispose,
e
);
});
}
public static IAsyncEnumerable<TResult> SelectManyAsync<TSource, TResult>(this IAsyncEnumerable<TSource> source, Func<TSource, Task<IAsyncEnumerable<TResult>>> selector)
{
if (source == null)
throw new ArgumentNullException(nameof(source));
if (selector == null)
throw new ArgumentNullException(nameof(selector));
return Create(() =>
{
var e = source.GetEnumerator();
var ie = default(IAsyncEnumerator<TResult>);
var innerDisposable = new AssignableDisposable();
var cts = new CancellationTokenDisposable();
var d = Disposable.Create(cts, innerDisposable, e);
// ReSharper disable once RedundantAssignment
var inner = default(Func<CancellationToken, Task<bool>>);
var outer = default(Func<CancellationToken, Task<bool>>);
inner = async ct =>
{
// ReSharper disable once PossibleNullReferenceException
if (await ie.MoveNext(ct).ConfigureAwait(false))
{
return true;
}
innerDisposable.Disposable = null;
// ReSharper disable once AccessToModifiedClosure
// ReSharper disable once PossibleNullReferenceException
return await outer(ct).ConfigureAwait(false);
};
outer = async ct =>
{
if (await e.MoveNext(ct).ConfigureAwait(false))
{
var enumerable = await selector(e.Current).ConfigureAwait(false);
ie = enumerable.GetEnumerator();
innerDisposable.Disposable = ie;
return await inner(ct).ConfigureAwait(false);
}
return false;
};
return Create(ct => ie == null ? outer(ct) : inner(ct),
() => ie.Current,
d.Dispose,
e
);
});
}
public static IAsyncEnumerable<TResult> SelectManyAsync<TSource, TResult>(this IAsyncEnumerable<TSource> source, Func<TSource, int, Task<IAsyncEnumerable<TResult>>> selector)
{
if (source == null)
throw new ArgumentNullException(nameof(source));
if (selector == null)
throw new ArgumentNullException(nameof(selector));
return Create(() =>
{
var e = source.GetEnumerator();
var ie = default(IAsyncEnumerator<TResult>);
var innerDisposable = new AssignableDisposable();
var index = 0;
var cts = new CancellationTokenDisposable();
var d = Disposable.Create(cts, innerDisposable, e);
// ReSharper disable once RedundantAssignment
var inner = default(Func<CancellationToken, Task<bool>>);
var outer = default(Func<CancellationToken, Task<bool>>);
inner = async ct =>
{
if (await e.MoveNext(ct).ConfigureAwait(false))
{
return true;
}
innerDisposable.Disposable = null;
// ReSharper disable once AccessToModifiedClosure
// ReSharper disable once PossibleNullReferenceException
return await outer(ct).ConfigureAwait(false);
};
outer = async ct =>
{
if (await e.MoveNext(ct).ConfigureAwait(false))
{
var enumerable = await selector(e.Current, checked(index++)).ConfigureAwait(false);
ie = enumerable.GetEnumerator();
innerDisposable.Disposable = ie;
return await inner(ct).ConfigureAwait(false);
}
return false;
};
return Create(ct => ie == null ? outer(ct) : inner(ct),
() => ie.Current,
d.Dispose,
e
);
});
}
public static async Task ForEachAsyncAsync<TSource>(this IAsyncEnumerable<TSource> source, Func<TSource, Task> action, CancellationToken cancellationToken)
{
if (source == null)
throw new ArgumentNullException(nameof(source));
if (action == null)
throw new ArgumentNullException(nameof(action));
using (var e = source.GetEnumerator())
{
while (await e.MoveNext(cancellationToken).ConfigureAwait(false))
{
await action(e.Current).ConfigureAwait(false);
}
}
}
public static async Task ForEachAsyncAsync<TSource>(this IAsyncEnumerable<TSource> source, Func<TSource, int, Task> action, CancellationToken cancellationToken)
{
if (source == null)
throw new ArgumentNullException(nameof(source));
if (action == null)
throw new ArgumentNullException(nameof(action));
var i = 0;
using (var e = source.GetEnumerator())
{
while (await e.MoveNext(cancellationToken).ConfigureAwait(false))
{
await action(e.Current, checked(i++)).ConfigureAwait(false);
}
}
}
#endregion
#region Wrappers
public static IAsyncEnumerable<T> AsAsyncEnumerable<T>(this Fabric.IAsyncEnumerable<T> enumerable)
{
return new AsyncEnumerableFabricWrapper<T>(enumerable);
}
private sealed class AsyncEnumerableFabricWrapper<T> : IAsyncEnumerable<T>
{
private readonly Fabric.IAsyncEnumerable<T> _inner;
public AsyncEnumerableFabricWrapper(Fabric.IAsyncEnumerable<T> inner)
{
_inner = inner;
}
public IAsyncEnumerator<T> GetEnumerator()
{
return new AsyncEnumeratorFabricWrapper(_inner.GetAsyncEnumerator());
}
private class AsyncEnumeratorFabricWrapper : IAsyncEnumerator<T>
{
private readonly Fabric.IAsyncEnumerator<T> _inner;
public AsyncEnumeratorFabricWrapper(Fabric.IAsyncEnumerator<T> inner)
{
_inner = inner;
}
public void Dispose() => _inner.Dispose();
public Task<bool> MoveNext(CancellationToken cancellationToken)
=> _inner.MoveNextAsync(cancellationToken);
public T Current => _inner.Current;
}
}
#endregion
}
public static class ReliableCollectionExtensions
{
public static async Task<IAsyncEnumerable<KeyValuePair<TKey, TValue>>> CreateLinqAsyncEnumerable<TKey, TValue>(
this IReliableDictionary<TKey, TValue> dictionary, Microsoft.ServiceFabric.Data.ITransaction txn)
where TKey : IComparable<TKey>, IEquatable<TKey>
{
var enumerable = await dictionary.CreateEnumerableAsync(txn).ConfigureAwait(false);
return enumerable.AsAsyncEnumerable();
}
public static async Task<IAsyncEnumerable<KeyValuePair<TKey, TValue>>> CreateLinqAsyncEnumerable<TKey, TValue>(
this IReliableDictionary<TKey, TValue> dictionary, Microsoft.ServiceFabric.Data.ITransaction txn, EnumerationMode enumerationMode)
where TKey : IComparable<TKey>, IEquatable<TKey>
{
var enumerable = await dictionary.CreateEnumerableAsync(txn, enumerationMode).ConfigureAwait(false);
return enumerable.AsAsyncEnumerable();
}
public static async Task<IAsyncEnumerable<KeyValuePair<TKey, TValue>>> CreateLinqAsyncEnumerable<TKey, TValue>(
this IReliableDictionary<TKey, TValue> dictionary, Microsoft.ServiceFabric.Data.ITransaction txn, Func<TKey, bool> filter, EnumerationMode enumerationMode)
where TKey : IComparable<TKey>, IEquatable<TKey>
{
var enumerable = await dictionary.CreateEnumerableAsync(txn, filter, enumerationMode).ConfigureAwait(false);
return enumerable.AsAsyncEnumerable();
}
public static async Task<IAsyncEnumerable<T>> CreateLinqAsyncEnumerable<T>(
this IReliableQueue<T> dictionary, Microsoft.ServiceFabric.Data.ITransaction txn)
{
var enumerable = await dictionary.CreateEnumerableAsync(txn).ConfigureAwait(false);
return enumerable.AsAsyncEnumerable();
}
}
internal static class SpecialTasks
{
public static Task<bool> False { get; } = Task.FromResult(false);
public static Task<bool> True { get; } = Task.FromResult(true);
}
internal class CancellationTokenDisposable : IDisposable
{
private readonly CancellationTokenSource _cts = new CancellationTokenSource();
public CancellationToken Token => _cts.Token;
public void Dispose()
{
if (!_cts.IsCancellationRequested)
{
_cts.Cancel();
}
}
}
internal class BinaryDisposable : IDisposable
{
private IDisposable _d1;
private IDisposable _d2;
public BinaryDisposable(IDisposable d1, IDisposable d2)
{
_d1 = d1;
_d2 = d2;
}
public void Dispose()
{
var d1 = Interlocked.Exchange(ref _d1, null);
if (d1 != null)
{
d1.Dispose();
var d2 = Interlocked.Exchange(ref _d2, null);
d2?.Dispose();
}
}
}
internal class Disposable : IDisposable
{
private static readonly Action _nop = () => { };
private Action _dispose;
public Disposable(Action dispose)
{
_dispose = dispose;
}
public static IDisposable Create(IDisposable d1, IDisposable d2)
{
return new BinaryDisposable(d1, d2);
}
public static IDisposable Create(params IDisposable[] disposables)
{
return new CompositeDisposable(disposables);
}
public void Dispose()
{
var dispose = Interlocked.Exchange(ref _dispose, _nop);
dispose();
}
}
internal class CompositeDisposable : IDisposable
{
private static readonly IDisposable[] _empty = new IDisposable[0];
private IDisposable[] _dispose;
public CompositeDisposable(params IDisposable[] dispose)
{
_dispose = dispose;
}
public void Dispose()
{
var dispose = Interlocked.Exchange(ref _dispose, _empty);
foreach (var d in dispose)
{
d.Dispose();
}
}
}
internal class AssignableDisposable : IDisposable
{
private readonly object _gate = new object();
private IDisposable _disposable;
private bool _disposed;
public IDisposable Disposable
{
set
{
lock (_gate)
{
DisposeInner();
_disposable = value;
if (_disposed)
{
DisposeInner();
}
}
}
}
public void Dispose()
{
lock (_gate)
{
if (!_disposed)
{
_disposed = true;
DisposeInner();
}
}
}
private void DisposeInner()
{
if (_disposable != null)
{
_disposable.Dispose();
_disposable = null;
}
}
}
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