Add cancel implementation for async commands.

Author: ChebanovDD

src/UnityMvvmToolkit.Core/BaseCommand.cs

@@ -14,7 +14,7 @@ protected BaseCommand(Func<bool> canExecute)
             _canExecute = canExecute;
         }
 
-        public event EventHandler<bool> CanExecuteChanged;
+        public virtual event EventHandler<bool> CanExecuteChanged;
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void RaiseCanExecuteChanged()

src/UnityMvvmToolkit.UnityPackage/Assets/Plugins/UnityMvvmToolkit/Runtime/Core/BaseCommand.cs

@@ -14,7 +14,7 @@ protected BaseCommand(Func<bool> canExecute)
             _canExecute = canExecute;
         }
 
-        public event EventHandler<bool> CanExecuteChanged;
+        public virtual event EventHandler<bool> CanExecuteChanged;
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void RaiseCanExecuteChanged()

src/UnityMvvmToolkit.UnityPackage/Assets/Plugins/UnityMvvmToolkit/Runtime/External/UniTask/BaseAsyncCommand.cs

@@ -15,8 +15,6 @@ protected BaseAsyncCommand(Func<bool> canExecute) : base(canExecute)
         {
         }
 
-        public bool DisableOnExecution { get; set; }
-
         public virtual bool IsRunning
         {
             get => _isRunning;
@@ -27,6 +25,8 @@ protected set
             }
         }
 
+        public virtual bool DisableOnExecution { get; set; }
+
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public override bool CanExecute()
         {
@@ -37,6 +37,10 @@ public override bool CanExecute()
 
             return IsRunning == false && base.CanExecute();
         }
+
+        public virtual void Cancel()
+        {
+        }
     }
 }
 

src/UnityMvvmToolkit.UnityPackage/Assets/Plugins/UnityMvvmToolkit/Runtime/External/UniTask/Extensions.meta

@@ -0,0 +1,33 @@
+#if UNITYMVVMTOOLKIT_UNITASK_SUPPORT
+
+namespace UnityMvvmToolkit.UniTask.Extensions
+{
+    using System;
+    using Internal;
+    using Interfaces;
+
+    public static class AsyncCommandExtensions
+    {
+        public static IAsyncCommand CreateCancelCommand(this IAsyncCommand asyncCommand)
+        {
+            if (asyncCommand == null)
+            {
+                throw new NullReferenceException(nameof(asyncCommand));
+            }
+
+            return new AsyncCommandWithCancellation(asyncCommand);
+        }
+
+        public static IAsyncCommand<T> CreateCancelCommand<T>(this IAsyncCommand<T> asyncCommand)
+        {
+            if (asyncCommand == null)
+            {
+                throw new NullReferenceException(nameof(asyncCommand));
+            }
+
+            return new AsyncCommandWithCancellation<T>(asyncCommand);
+        }
+    }
+}
+
+#endif

src/UnityMvvmToolkit.UnityPackage/Assets/Plugins/UnityMvvmToolkit/Runtime/External/UniTask/Extensions/AsyncCommandExtensions.cs

@@ -6,6 +6,8 @@ public interface IBaseAsyncCommand
     {
         bool IsRunning { get; }
         bool DisableOnExecution { get; set; }
+
+        void Cancel();
     }
 }
 

src/UnityMvvmToolkit.UnityPackage/Assets/Plugins/UnityMvvmToolkit/Runtime/External/UniTask/Extensions/AsyncCommandExtensions.cs.meta

@@ -0,0 +1,109 @@
+#if UNITYMVVMTOOLKIT_UNITASK_SUPPORT
+
+namespace UnityMvvmToolkit.UniTask.Internal
+{
+    using System;
+    using Interfaces;
+    using System.Threading;
+    using Cysharp.Threading.Tasks;
+
+    internal class AsyncCommandWithCancellation : BaseAsyncCommand, IAsyncCommand
+    {
+        private readonly IAsyncCommand _asyncCommand;
+        private CancellationTokenSource _cancellationTokenSource;
+
+        public AsyncCommandWithCancellation(IAsyncCommand asyncCommand) : base(null)
+        {
+            _asyncCommand = asyncCommand;
+        }
+
+        public override bool DisableOnExecution
+        {
+            get => _asyncCommand.DisableOnExecution;
+            set => _asyncCommand.DisableOnExecution = value;
+        }
+
+        public override event EventHandler<bool> CanExecuteChanged
+        {
+            add => _asyncCommand.CanExecuteChanged += value;
+            remove => _asyncCommand.CanExecuteChanged -= value;
+        }
+
+        public void Execute()
+        {
+            ExecuteAsync().Forget();
+        }
+
+        public async UniTask ExecuteAsync(CancellationToken cancellationToken = default)
+        {
+            _cancellationTokenSource?.Cancel();
+            _cancellationTokenSource = new CancellationTokenSource();
+
+            try
+            {
+                await _asyncCommand.ExecuteAsync(_cancellationTokenSource.Token);
+            }
+            finally
+            {
+                _cancellationTokenSource?.Dispose();
+                _cancellationTokenSource = null;
+            }
+        }
+
+        public override void Cancel()
+        {
+            _cancellationTokenSource?.Cancel();
+        }
+    }
+
+    internal class AsyncCommandWithCancellation<T> : BaseAsyncCommand, IAsyncCommand<T>
+    {
+        private readonly IAsyncCommand<T> _asyncCommand;
+        private CancellationTokenSource _cancellationTokenSource;
+
+        public AsyncCommandWithCancellation(IAsyncCommand<T> asyncCommand) : base(null)
+        {
+            _asyncCommand = asyncCommand;
+        }
+
+        public override bool DisableOnExecution
+        {
+            get => _asyncCommand.DisableOnExecution;
+            set => _asyncCommand.DisableOnExecution = value;
+        }
+
+        public override event EventHandler<bool> CanExecuteChanged
+        {
+            add => _asyncCommand.CanExecuteChanged += value;
+            remove => _asyncCommand.CanExecuteChanged -= value;
+        }
+
+        public void Execute(T parameter)
+        {
+            ExecuteAsync(parameter).Forget();
+        }
+
+        public async UniTask ExecuteAsync(T parameter, CancellationToken cancellationToken = default)
+        {
+            _cancellationTokenSource?.Cancel();
+            _cancellationTokenSource = new CancellationTokenSource();
+
+            try
+            {
+                await _asyncCommand.ExecuteAsync(parameter, _cancellationTokenSource.Token);
+            }
+            finally
+            {
+                _cancellationTokenSource?.Dispose();
+                _cancellationTokenSource = null;
+            }
+        }
+
+        public override void Cancel()
+        {
+            _cancellationTokenSource?.Cancel();
+        }
+    }
+}
+
+#endif