From d0035976625d5f1e66dc2bfb2a838ce276541bf3 Mon Sep 17 00:00:00 2001
From: neuecc <ils@neue.cc>
Date: Mon, 18 May 2020 11:30:49 +0900
Subject: [PATCH] Changed AsyncReactiveProperty produce current value at first,
 Add AsyncReactiveProperty.WithoutCurrent

---
 src/UniTask.NetCoreSandbox/Program.cs         | 26 ++-------
 .../AsyncReactivePropertyTest.cs              | 57 +++++++++++++++++++
 .../UniTask/Runtime/AsyncReactiveProperty.cs  | 34 ++++++++++-
 3 files changed, 93 insertions(+), 24 deletions(-)
 create mode 100644 src/UniTask.NetCoreTests/AsyncReactivePropertyTest.cs

diff --git a/src/UniTask.NetCoreSandbox/Program.cs b/src/UniTask.NetCoreSandbox/Program.cs
index e383db7..78dca8b 100644
--- a/src/UniTask.NetCoreSandbox/Program.cs
+++ b/src/UniTask.NetCoreSandbox/Program.cs
@@ -86,34 +86,16 @@ namespace NetCoreSandbox
             await Task.Delay(10, cancellationToken);
         }
 
-        private async UniTaskVoid HogeAsync()
+
+
+        static void Main(string[] args)
         {
-        }
 
-        static async Task Main(string[] args)
-        {
-            await foreach (var item in UniTaskAsyncEnumerable.Range(1, 10)
-                .SelectAwait(x => UniTask.Run(() => x))
-                .TakeLast(6)
-
-                
-
-                )
-            {
-
-                
-
-                Console.WriteLine(item);
-            }
-
-// AsyncEnumerable.Range(1,10).FirstAsync(
-            // AsyncEnumerable.Range(1, 10).GroupBy(x=>x).Select(x=>x.first
+            var channel = Channel.CreateSingleConsumerUnbounded<int>();
 
 
-            // AsyncEnumerable.Range(1,10).WithCancellation(CancellationToken.None).WithCancellation
 
 
-            //Enumerable.Range(1,10).ToHashSet(
 
 
         }
diff --git a/src/UniTask.NetCoreTests/AsyncReactivePropertyTest.cs b/src/UniTask.NetCoreTests/AsyncReactivePropertyTest.cs
new file mode 100644
index 0000000..3350763
--- /dev/null
+++ b/src/UniTask.NetCoreTests/AsyncReactivePropertyTest.cs
@@ -0,0 +1,57 @@
+using Cysharp.Threading.Tasks;
+using FluentAssertions;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading;
+using System.Threading.Channels;
+using Cysharp.Threading.Tasks.Linq;
+using System.Threading.Tasks;
+using Xunit;
+
+namespace NetCoreTests
+{
+    public class AsyncReactivePropertyTest
+    {
+        [Fact]
+        public async Task Iteration()
+        {
+            var rp = new AsyncReactiveProperty<int>(99);
+
+            var f = await rp.FirstAsync();
+            f.Should().Be(99);
+
+            var array = rp.Take(5).ToArrayAsync();
+
+            rp.Value = 100;
+            rp.Value = 100;
+            rp.Value = 100;
+            rp.Value = 131;
+
+            var ar = await array;
+
+            ar.Should().BeEquivalentTo(new[] { 99, 100, 100, 100, 131 });
+        }
+
+        [Fact]
+        public async Task WithoutCurrent()
+        {
+            var rp = new AsyncReactiveProperty<int>(99);
+
+            var array = rp.WithoutCurrent().Take(5).ToArrayAsync();
+
+            rp.Value = 100;
+            rp.Value = 100;
+            rp.Value = 100;
+            rp.Value = 131;
+            rp.Value = 191;
+
+            var ar = await array;
+
+            ar.Should().BeEquivalentTo(new[] { 100, 100, 100, 131, 191 });
+        }
+    }
+
+
+}
diff --git a/src/UniTask/Assets/Plugins/UniTask/Runtime/AsyncReactiveProperty.cs b/src/UniTask/Assets/Plugins/UniTask/Runtime/AsyncReactiveProperty.cs
index 21963e5..1866ce6 100644
--- a/src/UniTask/Assets/Plugins/UniTask/Runtime/AsyncReactiveProperty.cs
+++ b/src/UniTask/Assets/Plugins/UniTask/Runtime/AsyncReactiveProperty.cs
@@ -43,9 +43,14 @@ namespace Cysharp.Threading.Tasks
             this.triggerEvent = default;
         }
 
+        public IUniTaskAsyncEnumerable<T> WithoutCurrent()
+        {
+            return new WithoutCurrentEnumerable(this);
+        }
+
         public IUniTaskAsyncEnumerator<T> GetAsyncEnumerator(CancellationToken cancellationToken)
         {
-            return new Enumerator(this, cancellationToken);
+            return new Enumerator(this, cancellationToken, true);
         }
 
         public void Dispose()
@@ -53,6 +58,21 @@ namespace Cysharp.Threading.Tasks
             triggerEvent.SetCanceled(CancellationToken.None);
         }
 
+        class WithoutCurrentEnumerable : IUniTaskAsyncEnumerable<T>
+        {
+            readonly AsyncReactiveProperty<T> parent;
+
+            public WithoutCurrentEnumerable(AsyncReactiveProperty<T> parent)
+            {
+                this.parent = parent;
+            }
+
+            public IUniTaskAsyncEnumerator<T> GetAsyncEnumerator(CancellationToken cancellationToken = default)
+            {
+                return new Enumerator(parent, cancellationToken, false);
+            }
+        }
+
         sealed class Enumerator : MoveNextSource, IUniTaskAsyncEnumerator<T>, IResolveCancelPromise<T>
         {
             static Action<object> cancellationCallback = CancellationCallback;
@@ -62,11 +82,13 @@ namespace Cysharp.Threading.Tasks
             readonly CancellationTokenRegistration cancellationTokenRegistration;
             T value;
             bool isDisposed;
+            bool firstCall;
 
-            public Enumerator(AsyncReactiveProperty<T> parent, CancellationToken cancellationToken)
+            public Enumerator(AsyncReactiveProperty<T> parent, CancellationToken cancellationToken, bool publishCurrentValue)
             {
                 this.parent = parent;
                 this.cancellationToken = cancellationToken;
+                this.firstCall = publishCurrentValue;
 
                 parent.triggerEvent.Add(this);
                 TaskTracker.TrackActiveTask(this, 3);
@@ -81,6 +103,14 @@ namespace Cysharp.Threading.Tasks
 
             public UniTask<bool> MoveNextAsync()
             {
+                // raise latest value on first call.
+                if (firstCall)
+                {
+                    firstCall = false;
+                    value = parent.Value;
+                    return CompletedTasks.True;
+                }
+
                 completionSource.Reset();
                 return new UniTask<bool>(this, completionSource.Version);
             }