Adding TakeUntil and SkipUntil.

AsyncRx.NET/System.Reactive.Async/System/Reactive/Linq/Operators/SkipUntil.cs

@@ -0,0 +1,90 @@
+// 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.Reactive.Disposables;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace System.Reactive.Linq
+{
+    partial class AsyncObservable
+    {
+        public static IAsyncObservable<TSource> SkipUntil<TSource, TUntil>(this IAsyncObservable<TSource> source, IAsyncObservable<TUntil> until)
+        {
+            if (source == null)
+                throw new ArgumentNullException(nameof(source));
+            if (until == null)
+                throw new ArgumentNullException(nameof(until));
+
+            return Create<TSource>(async observer =>
+            {
+                var (sourceObserver, untilObserver) = AsyncObserver.SkipUntil<TSource, TUntil>(observer);
+
+                var d1 = await source.SubscribeAsync(sourceObserver).ConfigureAwait(false);
+                var d2 = await until.SubscribeAsync(untilObserver).ConfigureAwait(false);
+
+                return StableCompositeAsyncDisposable.Create(d1, d2);
+            });
+        }
+    }
+
+    partial class AsyncObserver
+    {
+        public static (IAsyncObserver<TSource>, IAsyncObserver<TUntil>) SkipUntil<TSource, TUntil>(IAsyncObserver<TSource> observer)
+        {
+            if (observer == null)
+                throw new ArgumentNullException(nameof(observer));
+
+            var gate = new AsyncLock();
+            var open = false;
+
+            return
+                (
+                    Create<TSource>(
+                        async x =>
+                        {
+                            using (await gate.LockAsync().ConfigureAwait(false))
+                            {
+                                if (open)
+                                {
+                                    await observer.OnNextAsync(x).ConfigureAwait(false);
+                                }
+                            }
+                        },
+                        async ex =>
+                        {
+                            using (await gate.LockAsync().ConfigureAwait(false))
+                            {
+                                await observer.OnErrorAsync(ex).ConfigureAwait(false);
+                            }
+                        },
+                        async () =>
+                        {
+                            using (await gate.LockAsync().ConfigureAwait(false))
+                            {
+                                await observer.OnCompletedAsync().ConfigureAwait(false);
+                            }
+                        }
+                    ),
+                    Create<TUntil>(
+                        async y =>
+                        {
+                            using (await gate.LockAsync().ConfigureAwait(false))
+                            {
+                                open = true;
+                            }
+                        },
+                        async ex =>
+                        {
+                            using (await gate.LockAsync().ConfigureAwait(false))
+                            {
+                                await observer.OnErrorAsync(ex).ConfigureAwait(false);
+                            }
+                        },
+                        () => Task.CompletedTask
+                    )
+                );
+        }
+    }
+}

AsyncRx.NET/System.Reactive.Async/System/Reactive/Linq/Operators/TakeUntil.cs

@@ -0,0 +1,86 @@
+// 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.Reactive.Disposables;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace System.Reactive.Linq
+{
+    partial class AsyncObservable
+    {
+        public static IAsyncObservable<TSource> TakeUntil<TSource, TUntil>(this IAsyncObservable<TSource> source, IAsyncObservable<TUntil> until)
+        {
+            if (source == null)
+                throw new ArgumentNullException(nameof(source));
+            if (until == null)
+                throw new ArgumentNullException(nameof(until));
+
+            return Create<TSource>(async observer =>
+            {
+                var (sourceObserver, untilObserver) = AsyncObserver.TakeUntil<TSource, TUntil>(observer);
+
+                var d1 = await source.SubscribeAsync(sourceObserver).ConfigureAwait(false);
+                var d2 = await until.SubscribeAsync(untilObserver).ConfigureAwait(false);
+
+                return StableCompositeAsyncDisposable.Create(d1, d2);
+            });
+        }
+    }
+
+    partial class AsyncObserver
+    {
+        public static (IAsyncObserver<TSource>, IAsyncObserver<TUntil>) TakeUntil<TSource, TUntil>(IAsyncObserver<TSource> observer)
+        {
+            if (observer == null)
+                throw new ArgumentNullException(nameof(observer));
+
+            var gate = new AsyncLock();
+
+            return
+                (
+                    Create<TSource>(
+                        async x =>
+                        {
+                            using (await gate.LockAsync().ConfigureAwait(false))
+                            {
+                                await observer.OnNextAsync(x).ConfigureAwait(false);
+                            }
+                        },
+                        async ex =>
+                        {
+                            using (await gate.LockAsync().ConfigureAwait(false))
+                            {
+                                await observer.OnErrorAsync(ex).ConfigureAwait(false);
+                            }
+                        },
+                        async () =>
+                        {
+                            using (await gate.LockAsync().ConfigureAwait(false))
+                            {
+                                await observer.OnCompletedAsync().ConfigureAwait(false);
+                            }
+                        }
+                    ),
+                    Create<TUntil>(
+                        async y =>
+                        {
+                            using (await gate.LockAsync().ConfigureAwait(false))
+                            {
+                                await observer.OnCompletedAsync().ConfigureAwait(false);
+                            }
+                        },
+                        async ex =>
+                        {
+                            using (await gate.LockAsync().ConfigureAwait(false))
+                            {
+                                await observer.OnErrorAsync(ex).ConfigureAwait(false);
+                            }
+                        },
+                        () => Task.CompletedTask
+                    )
+                );
+        }
+    }
+}