reactive/Ix.NET/Source/System.Interactive.Async/OrderBy.cs

// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the Apache 2.0 License.
// See the LICENSE file in the project root for more information. 

using System.Collections.Generic;

namespace System.Linq
{
    public static partial class AsyncEnumerable
    {
        public static IOrderedAsyncEnumerable<TSource> OrderBy<TSource, TKey>(this IAsyncEnumerable<TSource> source, Func<TSource, TKey> keySelector, IComparer<TKey> comparer)
        {
            if (source == null)
            {
                throw new ArgumentNullException(nameof(source));
            }

            if (keySelector == null)
            {
                throw new ArgumentNullException(nameof(keySelector));
            }

            if (comparer == null)
            {
                throw new ArgumentNullException(nameof(comparer));
            }

            return new OrderedAsyncEnumerable<TSource, TKey>(source, keySelector, comparer, false, null);
        }

        public static IOrderedAsyncEnumerable<TSource> OrderBy<TSource, TKey>(this IAsyncEnumerable<TSource> source, Func<TSource, TKey> keySelector)
        {
            if (source == null)
            {
                throw new ArgumentNullException(nameof(source));
            }

            if (keySelector == null)
            {
                throw new ArgumentNullException(nameof(keySelector));
            }

            return source.OrderBy(keySelector, Comparer<TKey>.Default);
        }

        public static IOrderedAsyncEnumerable<TSource> OrderByDescending<TSource, TKey>(this IAsyncEnumerable<TSource> source, Func<TSource, TKey> keySelector, IComparer<TKey> comparer)
        {
            if (source == null)
            {
                throw new ArgumentNullException(nameof(source));
            }

            if (keySelector == null)
            {
                throw new ArgumentNullException(nameof(keySelector));
            }

            if (comparer == null)
            {
                throw new ArgumentNullException(nameof(comparer));
            }

            return new OrderedAsyncEnumerable<TSource, TKey>(source, keySelector, comparer, true, null);
        }

        public static IOrderedAsyncEnumerable<TSource> OrderByDescending<TSource, TKey>(this IAsyncEnumerable<TSource> source, Func<TSource, TKey> keySelector)
        {
            if (source == null)
            {
                throw new ArgumentNullException(nameof(source));
            }

            if (keySelector == null)
            {
                throw new ArgumentNullException(nameof(keySelector));
            }

            return source.OrderByDescending(keySelector, Comparer<TKey>.Default);
        }

        public static IOrderedAsyncEnumerable<TSource> ThenBy<TSource, TKey>(this IOrderedAsyncEnumerable<TSource> source, Func<TSource, TKey> keySelector)
        {
            if (source == null)
            {
                throw new ArgumentNullException(nameof(source));
            }

            if (keySelector == null)
            {
                throw new ArgumentNullException(nameof(keySelector));
            }

            return source.ThenBy(keySelector, Comparer<TKey>.Default);
        }

        public static IOrderedAsyncEnumerable<TSource> ThenBy<TSource, TKey>(this IOrderedAsyncEnumerable<TSource> source, Func<TSource, TKey> keySelector, IComparer<TKey> comparer)
        {
            if (source == null)
            {
                throw new ArgumentNullException(nameof(source));
            }

            if (keySelector == null)
            {
                throw new ArgumentNullException(nameof(keySelector));
            }

            if (comparer == null)
            {
                throw new ArgumentNullException(nameof(comparer));
            }

            return source.CreateOrderedEnumerable(keySelector, comparer, false);
        }

        public static IOrderedAsyncEnumerable<TSource> ThenByDescending<TSource, TKey>(this IOrderedAsyncEnumerable<TSource> source, Func<TSource, TKey> keySelector)
        {
            if (source == null)
            {
                throw new ArgumentNullException(nameof(source));
            }

            if (keySelector == null)
            {
                throw new ArgumentNullException(nameof(keySelector));
            }

            return source.ThenByDescending(keySelector, Comparer<TKey>.Default);
        }

        public static IOrderedAsyncEnumerable<TSource> ThenByDescending<TSource, TKey>(this IOrderedAsyncEnumerable<TSource> source, Func<TSource, TKey> keySelector, IComparer<TKey> comparer)
        {
            if (source == null)
            {
                throw new ArgumentNullException(nameof(source));
            }

            if (keySelector == null)
            {
                throw new ArgumentNullException(nameof(keySelector));
            }

            if (comparer == null)
            {
                throw new ArgumentNullException(nameof(comparer));
            }

            return source.CreateOrderedEnumerable(keySelector, comparer, true);
        }
    }
}