Splitting Distinct and DistinctUntilChanged.

Ix.NET/Source/System.Interactive.Async/Distinct.cs

@@ -73,78 +73,6 @@ namespace System.Linq
             return new DistinctAsyncIteratorWithTask<TSource, TKey>(source, keySelector, comparer);
         }
 
-        public static IAsyncEnumerable<TSource> DistinctUntilChanged<TSource>(this IAsyncEnumerable<TSource> source)
-        {
-            if (source == null)
-                throw new ArgumentNullException(nameof(source));
-
-            return source.DistinctUntilChanged(EqualityComparer<TSource>.Default);
-        }
-
-        public static IAsyncEnumerable<TSource> DistinctUntilChanged<TSource>(this IAsyncEnumerable<TSource> source, IEqualityComparer<TSource> comparer)
-        {
-            if (source == null)
-                throw new ArgumentNullException(nameof(source));
-            if (comparer == null)
-                throw new ArgumentNullException(nameof(comparer));
-
-            return new DistinctUntilChangedAsyncIterator<TSource>(source, comparer);
-        }
-
-        public static IAsyncEnumerable<TSource> DistinctUntilChanged<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.DistinctUntilChanged_(keySelector, EqualityComparer<TKey>.Default);
-        }
-
-        public static IAsyncEnumerable<TSource> DistinctUntilChanged<TSource, TKey>(this IAsyncEnumerable<TSource> source, Func<TSource, TKey> keySelector, IEqualityComparer<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.DistinctUntilChanged_(keySelector, comparer);
-        }
-
-        public static IAsyncEnumerable<TSource> DistinctUntilChanged<TSource, TKey>(this IAsyncEnumerable<TSource> source, Func<TSource, Task<TKey>> keySelector)
-        {
-            if (source == null)
-                throw new ArgumentNullException(nameof(source));
-            if (keySelector == null)
-                throw new ArgumentNullException(nameof(keySelector));
-
-            return source.DistinctUntilChanged_(keySelector, EqualityComparer<TKey>.Default);
-        }
-
-        public static IAsyncEnumerable<TSource> DistinctUntilChanged<TSource, TKey>(this IAsyncEnumerable<TSource> source, Func<TSource, Task<TKey>> keySelector, IEqualityComparer<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.DistinctUntilChanged_(keySelector, comparer);
-        }
-
-        private static IAsyncEnumerable<TSource> DistinctUntilChanged_<TSource, TKey>(this IAsyncEnumerable<TSource> source, Func<TSource, TKey> keySelector, IEqualityComparer<TKey> comparer)
-        {
-            return new DistinctUntilChangedAsyncIterator<TSource, TKey>(source, keySelector, comparer);
-        }
-
-        private static IAsyncEnumerable<TSource> DistinctUntilChanged_<TSource, TKey>(this IAsyncEnumerable<TSource> source, Func<TSource, Task<TKey>> keySelector, IEqualityComparer<TKey> comparer)
-        {
-            return new DistinctUntilChangedAsyncIteratorWithTask<TSource, TKey>(source, keySelector, comparer);
-        }
-
         private sealed class DistinctAsyncIterator<TSource> : AsyncIterator<TSource>, IIListProvider<TSource>
         {
             private readonly IEqualityComparer<TSource> comparer;
@@ -547,219 +475,5 @@ namespace System.Linq
                 return r;
             }
         }
-
-        private sealed class DistinctUntilChangedAsyncIterator<TSource> : AsyncIterator<TSource>
-        {
-            private readonly IEqualityComparer<TSource> comparer;
-            private readonly IAsyncEnumerable<TSource> source;
-
-            private TSource currentValue;
-            private IAsyncEnumerator<TSource> enumerator;
-            private bool hasCurrentValue;
-
-            public DistinctUntilChangedAsyncIterator(IAsyncEnumerable<TSource> source, IEqualityComparer<TSource> comparer)
-            {
-                Debug.Assert(comparer != null);
-                Debug.Assert(source != null);
-
-                this.source = source;
-                this.comparer = comparer;
-            }
-
-            public override AsyncIterator<TSource> Clone()
-            {
-                return new DistinctUntilChangedAsyncIterator<TSource>(source, comparer);
-            }
-
-            public override async Task DisposeAsync()
-            {
-                if (enumerator != null)
-                {
-                    await enumerator.DisposeAsync().ConfigureAwait(false);
-                    enumerator = null;
-                    currentValue = default(TSource);
-                }
-
-                await base.DisposeAsync().ConfigureAwait(false);
-            }
-
-            protected override async Task<bool> MoveNextCore()
-            {
-                switch (state)
-                {
-                    case AsyncIteratorState.Allocated:
-                        enumerator = source.GetAsyncEnumerator();
-                        state = AsyncIteratorState.Iterating;
-                        goto case AsyncIteratorState.Iterating;
-
-                    case AsyncIteratorState.Iterating:
-                        while (await enumerator.MoveNextAsync().ConfigureAwait(false))
-                        {
-                            var item = enumerator.Current;
-                            var comparerEquals = false;
-
-                            if (hasCurrentValue)
-                            {
-                                comparerEquals = comparer.Equals(currentValue, item);
-                            }
-
-                            if (!hasCurrentValue || !comparerEquals)
-                            {
-                                hasCurrentValue = true;
-                                currentValue = item;
-                                current = item;
-                                return true;
-                            }
-                        }
-
-                        break;
-                }
-
-                await DisposeAsync().ConfigureAwait(false);
-                return false;
-            }
-        }
-
-        private sealed class DistinctUntilChangedAsyncIterator<TSource, TKey> : AsyncIterator<TSource>
-        {
-            private readonly IEqualityComparer<TKey> comparer;
-            private readonly Func<TSource, TKey> keySelector;
-            private readonly IAsyncEnumerable<TSource> source;
-            private TKey currentKeyValue;
-
-            private IAsyncEnumerator<TSource> enumerator;
-            private bool hasCurrentKey;
-
-            public DistinctUntilChangedAsyncIterator(IAsyncEnumerable<TSource> source, Func<TSource, TKey> keySelector, IEqualityComparer<TKey> comparer)
-            {
-                this.source = source;
-                this.keySelector = keySelector;
-                this.comparer = comparer;
-            }
-
-            public override AsyncIterator<TSource> Clone()
-            {
-                return new DistinctUntilChangedAsyncIterator<TSource, TKey>(source, keySelector, comparer);
-            }
-
-            public override async Task DisposeAsync()
-            {
-                if (enumerator != null)
-                {
-                    await enumerator.DisposeAsync().ConfigureAwait(false);
-                    enumerator = null;
-                    currentKeyValue = default(TKey);
-                }
-
-                await base.DisposeAsync().ConfigureAwait(false);
-            }
-
-            protected override async Task<bool> MoveNextCore()
-            {
-                switch (state)
-                {
-                    case AsyncIteratorState.Allocated:
-                        enumerator = source.GetAsyncEnumerator();
-                        state = AsyncIteratorState.Iterating;
-                        goto case AsyncIteratorState.Iterating;
-
-                    case AsyncIteratorState.Iterating:
-                        while (await enumerator.MoveNextAsync().ConfigureAwait(false))
-                        {
-                            var item = enumerator.Current;
-                            var key = keySelector(item);
-                            var comparerEquals = false;
-
-                            if (hasCurrentKey)
-                            {
-                                comparerEquals = comparer.Equals(currentKeyValue, key);
-                            }
-                            if (!hasCurrentKey || !comparerEquals)
-                            {
-                                hasCurrentKey = true;
-                                currentKeyValue = key;
-                                current = item;
-                                return true;
-                            }
-                        }
-
-                        break; // case
-                }
-
-                await DisposeAsync().ConfigureAwait(false);
-                return false;
-            }
-        }
-
-        private sealed class DistinctUntilChangedAsyncIteratorWithTask<TSource, TKey> : AsyncIterator<TSource>
-        {
-            private readonly IEqualityComparer<TKey> comparer;
-            private readonly Func<TSource, Task<TKey>> keySelector;
-            private readonly IAsyncEnumerable<TSource> source;
-            private TKey currentKeyValue;
-
-            private IAsyncEnumerator<TSource> enumerator;
-            private bool hasCurrentKey;
-
-            public DistinctUntilChangedAsyncIteratorWithTask(IAsyncEnumerable<TSource> source, Func<TSource, Task<TKey>> keySelector, IEqualityComparer<TKey> comparer)
-            {
-                this.source = source;
-                this.keySelector = keySelector;
-                this.comparer = comparer;
-            }
-
-            public override AsyncIterator<TSource> Clone()
-            {
-                return new DistinctUntilChangedAsyncIteratorWithTask<TSource, TKey>(source, keySelector, comparer);
-            }
-
-            public override async Task DisposeAsync()
-            {
-                if (enumerator != null)
-                {
-                    await enumerator.DisposeAsync().ConfigureAwait(false);
-                    enumerator = null;
-                    currentKeyValue = default(TKey);
-                }
-
-                await base.DisposeAsync().ConfigureAwait(false);
-            }
-
-            protected override async Task<bool> MoveNextCore()
-            {
-                switch (state)
-                {
-                    case AsyncIteratorState.Allocated:
-                        enumerator = source.GetAsyncEnumerator();
-                        state = AsyncIteratorState.Iterating;
-                        goto case AsyncIteratorState.Iterating;
-
-                    case AsyncIteratorState.Iterating:
-                        while (await enumerator.MoveNextAsync().ConfigureAwait(false))
-                        {
-                            var item = enumerator.Current;
-                            var key = await keySelector(item).ConfigureAwait(false);
-                            var comparerEquals = false;
-
-                            if (hasCurrentKey)
-                            {
-                                comparerEquals = comparer.Equals(currentKeyValue, key);
-                            }
-                            if (!hasCurrentKey || !comparerEquals)
-                            {
-                                hasCurrentKey = true;
-                                currentKeyValue = key;
-                                current = item;
-                                return true;
-                            }
-                        }
-
-                        break; // case
-                }
-
-                await DisposeAsync().ConfigureAwait(false);
-                return false;
-            }
-        }
     }
 }

Ix.NET/Source/System.Interactive.Async/DistinctUntilChanged.cs

@@ -0,0 +1,300 @@
+// 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;
+using System.Diagnostics;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace System.Linq
+{
+    public static partial class AsyncEnumerable
+    {
+        public static IAsyncEnumerable<TSource> DistinctUntilChanged<TSource>(this IAsyncEnumerable<TSource> source)
+        {
+            if (source == null)
+                throw new ArgumentNullException(nameof(source));
+
+            return source.DistinctUntilChanged(EqualityComparer<TSource>.Default);
+        }
+
+        public static IAsyncEnumerable<TSource> DistinctUntilChanged<TSource>(this IAsyncEnumerable<TSource> source, IEqualityComparer<TSource> comparer)
+        {
+            if (source == null)
+                throw new ArgumentNullException(nameof(source));
+            if (comparer == null)
+                throw new ArgumentNullException(nameof(comparer));
+
+            return new DistinctUntilChangedAsyncIterator<TSource>(source, comparer);
+        }
+
+        public static IAsyncEnumerable<TSource> DistinctUntilChanged<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.DistinctUntilChanged_(keySelector, EqualityComparer<TKey>.Default);
+        }
+
+        public static IAsyncEnumerable<TSource> DistinctUntilChanged<TSource, TKey>(this IAsyncEnumerable<TSource> source, Func<TSource, TKey> keySelector, IEqualityComparer<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.DistinctUntilChanged_(keySelector, comparer);
+        }
+
+        public static IAsyncEnumerable<TSource> DistinctUntilChanged<TSource, TKey>(this IAsyncEnumerable<TSource> source, Func<TSource, Task<TKey>> keySelector)
+        {
+            if (source == null)
+                throw new ArgumentNullException(nameof(source));
+            if (keySelector == null)
+                throw new ArgumentNullException(nameof(keySelector));
+
+            return source.DistinctUntilChanged_(keySelector, EqualityComparer<TKey>.Default);
+        }
+
+        public static IAsyncEnumerable<TSource> DistinctUntilChanged<TSource, TKey>(this IAsyncEnumerable<TSource> source, Func<TSource, Task<TKey>> keySelector, IEqualityComparer<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.DistinctUntilChanged_(keySelector, comparer);
+        }
+
+        private static IAsyncEnumerable<TSource> DistinctUntilChanged_<TSource, TKey>(this IAsyncEnumerable<TSource> source, Func<TSource, TKey> keySelector, IEqualityComparer<TKey> comparer)
+        {
+            return new DistinctUntilChangedAsyncIterator<TSource, TKey>(source, keySelector, comparer);
+        }
+
+        private static IAsyncEnumerable<TSource> DistinctUntilChanged_<TSource, TKey>(this IAsyncEnumerable<TSource> source, Func<TSource, Task<TKey>> keySelector, IEqualityComparer<TKey> comparer)
+        {
+            return new DistinctUntilChangedAsyncIteratorWithTask<TSource, TKey>(source, keySelector, comparer);
+        }
+
+        private sealed class DistinctUntilChangedAsyncIterator<TSource> : AsyncIterator<TSource>
+        {
+            private readonly IEqualityComparer<TSource> comparer;
+            private readonly IAsyncEnumerable<TSource> source;
+
+            private TSource currentValue;
+            private IAsyncEnumerator<TSource> enumerator;
+            private bool hasCurrentValue;
+
+            public DistinctUntilChangedAsyncIterator(IAsyncEnumerable<TSource> source, IEqualityComparer<TSource> comparer)
+            {
+                Debug.Assert(comparer != null);
+                Debug.Assert(source != null);
+
+                this.source = source;
+                this.comparer = comparer;
+            }
+
+            public override AsyncIterator<TSource> Clone()
+            {
+                return new DistinctUntilChangedAsyncIterator<TSource>(source, comparer);
+            }
+
+            public override async Task DisposeAsync()
+            {
+                if (enumerator != null)
+                {
+                    await enumerator.DisposeAsync().ConfigureAwait(false);
+                    enumerator = null;
+                    currentValue = default(TSource);
+                }
+
+                await base.DisposeAsync().ConfigureAwait(false);
+            }
+
+            protected override async Task<bool> MoveNextCore()
+            {
+                switch (state)
+                {
+                    case AsyncIteratorState.Allocated:
+                        enumerator = source.GetAsyncEnumerator();
+                        state = AsyncIteratorState.Iterating;
+                        goto case AsyncIteratorState.Iterating;
+
+                    case AsyncIteratorState.Iterating:
+                        while (await enumerator.MoveNextAsync().ConfigureAwait(false))
+                        {
+                            var item = enumerator.Current;
+                            var comparerEquals = false;
+
+                            if (hasCurrentValue)
+                            {
+                                comparerEquals = comparer.Equals(currentValue, item);
+                            }
+
+                            if (!hasCurrentValue || !comparerEquals)
+                            {
+                                hasCurrentValue = true;
+                                currentValue = item;
+                                current = item;
+                                return true;
+                            }
+                        }
+
+                        break;
+                }
+
+                await DisposeAsync().ConfigureAwait(false);
+                return false;
+            }
+        }
+
+        private sealed class DistinctUntilChangedAsyncIterator<TSource, TKey> : AsyncIterator<TSource>
+        {
+            private readonly IEqualityComparer<TKey> comparer;
+            private readonly Func<TSource, TKey> keySelector;
+            private readonly IAsyncEnumerable<TSource> source;
+            private TKey currentKeyValue;
+
+            private IAsyncEnumerator<TSource> enumerator;
+            private bool hasCurrentKey;
+
+            public DistinctUntilChangedAsyncIterator(IAsyncEnumerable<TSource> source, Func<TSource, TKey> keySelector, IEqualityComparer<TKey> comparer)
+            {
+                this.source = source;
+                this.keySelector = keySelector;
+                this.comparer = comparer;
+            }
+
+            public override AsyncIterator<TSource> Clone()
+            {
+                return new DistinctUntilChangedAsyncIterator<TSource, TKey>(source, keySelector, comparer);
+            }
+
+            public override async Task DisposeAsync()
+            {
+                if (enumerator != null)
+                {
+                    await enumerator.DisposeAsync().ConfigureAwait(false);
+                    enumerator = null;
+                    currentKeyValue = default(TKey);
+                }
+
+                await base.DisposeAsync().ConfigureAwait(false);
+            }
+
+            protected override async Task<bool> MoveNextCore()
+            {
+                switch (state)
+                {
+                    case AsyncIteratorState.Allocated:
+                        enumerator = source.GetAsyncEnumerator();
+                        state = AsyncIteratorState.Iterating;
+                        goto case AsyncIteratorState.Iterating;
+
+                    case AsyncIteratorState.Iterating:
+                        while (await enumerator.MoveNextAsync().ConfigureAwait(false))
+                        {
+                            var item = enumerator.Current;
+                            var key = keySelector(item);
+                            var comparerEquals = false;
+
+                            if (hasCurrentKey)
+                            {
+                                comparerEquals = comparer.Equals(currentKeyValue, key);
+                            }
+                            if (!hasCurrentKey || !comparerEquals)
+                            {
+                                hasCurrentKey = true;
+                                currentKeyValue = key;
+                                current = item;
+                                return true;
+                            }
+                        }
+
+                        break; // case
+                }
+
+                await DisposeAsync().ConfigureAwait(false);
+                return false;
+            }
+        }
+
+        private sealed class DistinctUntilChangedAsyncIteratorWithTask<TSource, TKey> : AsyncIterator<TSource>
+        {
+            private readonly IEqualityComparer<TKey> comparer;
+            private readonly Func<TSource, Task<TKey>> keySelector;
+            private readonly IAsyncEnumerable<TSource> source;
+            private TKey currentKeyValue;
+
+            private IAsyncEnumerator<TSource> enumerator;
+            private bool hasCurrentKey;
+
+            public DistinctUntilChangedAsyncIteratorWithTask(IAsyncEnumerable<TSource> source, Func<TSource, Task<TKey>> keySelector, IEqualityComparer<TKey> comparer)
+            {
+                this.source = source;
+                this.keySelector = keySelector;
+                this.comparer = comparer;
+            }
+
+            public override AsyncIterator<TSource> Clone()
+            {
+                return new DistinctUntilChangedAsyncIteratorWithTask<TSource, TKey>(source, keySelector, comparer);
+            }
+
+            public override async Task DisposeAsync()
+            {
+                if (enumerator != null)
+                {
+                    await enumerator.DisposeAsync().ConfigureAwait(false);
+                    enumerator = null;
+                    currentKeyValue = default(TKey);
+                }
+
+                await base.DisposeAsync().ConfigureAwait(false);
+            }
+
+            protected override async Task<bool> MoveNextCore()
+            {
+                switch (state)
+                {
+                    case AsyncIteratorState.Allocated:
+                        enumerator = source.GetAsyncEnumerator();
+                        state = AsyncIteratorState.Iterating;
+                        goto case AsyncIteratorState.Iterating;
+
+                    case AsyncIteratorState.Iterating:
+                        while (await enumerator.MoveNextAsync().ConfigureAwait(false))
+                        {
+                            var item = enumerator.Current;
+                            var key = await keySelector(item).ConfigureAwait(false);
+                            var comparerEquals = false;
+
+                            if (hasCurrentKey)
+                            {
+                                comparerEquals = comparer.Equals(currentKeyValue, key);
+                            }
+                            if (!hasCurrentKey || !comparerEquals)
+                            {
+                                hasCurrentKey = true;
+                                currentKeyValue = key;
+                                current = item;
+                                return true;
+                            }
+                        }
+
+                        break; // case
+                }
+
+                await DisposeAsync().ConfigureAwait(false);
+                return false;
+            }
+        }
+    }
+}