Add CancellationToken support to prompts

README.md

@@ -182,6 +182,11 @@ catch (PromptCanceledException ex)
 {
     Console.WriteLine("Prompt canceled");
 }
+
+// Cancel from code with a CancellationToken (throws OperationCanceledException)
+using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(30));
+
+var answer = Prompt.Confirm(options => options.Message = "Are you ready?", cts.Token);
 ```
 
 ## Validators

docs/en/configuration.md

@@ -52,7 +52,7 @@ var name = Prompt.Input<string>("What's your name?");
 
 ## Cancellation Support
 
-By default, pressing `Ctrl+C` returns the default value. You can change this behavior to throw an exception:
+By default, pressing `Ctrl+C` or `Esc` exits the process. You can change this behavior to throw an exception:
 
 ```csharp
 Prompt.ThrowExceptionOnCancel = true;
@@ -68,6 +68,24 @@ catch (PromptCanceledException ex)
 }
 ```
 
+### Canceling from code
+
+Every prompt accepts a `CancellationToken` through the overloads that take an options object or a configure delegate, and `Prompt.Bind` accepts one too. When the token is canceled while the prompt is waiting for input, the prompt is closed and an `OperationCanceledException` is thrown, regardless of `ThrowExceptionOnCancel`.
+
+```csharp
+using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(30));
+
+try
+{
+    var name = Prompt.Input<string>(options => options.Message = "What's your name?", cts.Token);
+    Console.WriteLine($"Hello, {name}!");
+}
+catch (OperationCanceledException)
+{
+    Console.WriteLine("Timed out");
+}
+```
+
 ## Culture
 
 Set the culture for localized messages:

docs/ja/configuration.md

@@ -52,7 +52,7 @@ var name = Prompt.Input<string>("What's your name?");
 
 ## キャンセルのサポート
 
-デフォルトでは、`Ctrl+C` を押すとデフォルト値が返されます。この動作を変更して例外をスローさせることができます:
+デフォルトでは、`Ctrl+C` または `Esc` を押すとプロセスが終了します。この動作を変更して例外をスローさせることができます:
 
 ```csharp
 Prompt.ThrowExceptionOnCancel = true;
@@ -68,6 +68,24 @@ catch (PromptCanceledException ex)
 }
 ```
 
+### コードからのキャンセル
+
+すべてのプロンプトは、オプションオブジェクトまたは構成デリゲートを受け取るオーバーロードで `CancellationToken` を指定できます。`Prompt.Bind` も同様です。入力待ちの間にトークンがキャンセルされると、プロンプトを閉じて `OperationCanceledException` をスローします。この動作は `ThrowExceptionOnCancel` の設定に関係ありません。
+
+```csharp
+using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(30));
+
+try
+{
+    var name = Prompt.Input<string>(options => options.Message = "What's your name?", cts.Token);
+    Console.WriteLine($"Hello, {name}!");
+}
+catch (OperationCanceledException)
+{
+    Console.WriteLine("Timed out");
+}
+```
+
 ## カルチャ
 
 ローカライズされたメッセージのカルチャを設定します:

src/Sharprompt.SourceGenerator/PromptBindableGenerator.cs

@@ -84,7 +84,7 @@ private static (string HintName, string Source) Transform(GeneratorAttributeSynt
         builder.AppendLine("    [global::System.Runtime.CompilerServices.ModuleInitializer]");
         builder.AppendLine("    internal static void Register()");
         builder.AppendLine("    {");
-        builder.AppendLine("        global::Sharprompt.ModelBinderRegistry.Register<" + fullTypeName + ">(model =>");
+        builder.AppendLine("        global::Sharprompt.ModelBinderRegistry.Register<" + fullTypeName + ">((model, cancellationToken) =>");
         builder.AppendLine("        {");
 
         for (var i = 0; i < properties.Count; i++)
@@ -333,7 +333,7 @@ private static void EmitInput(StringBuilder builder, PropertyMetadata property,
 
         builder.AppendLine(indent + "    options.DefaultValue = model." + property.Name + ";");
         EmitValidators(builder, property, indent);
-        builder.AppendLine(indent + "});");
+        builder.AppendLine(indent + "}, cancellationToken);");
     }
 
     private static void EmitPassword(StringBuilder builder, PropertyMetadata property, string indent)
@@ -348,7 +348,7 @@ private static void EmitPassword(StringBuilder builder, PropertyMetadata propert
         }
 
         EmitValidators(builder, property, indent);
-        builder.AppendLine(indent + "});");
+        builder.AppendLine(indent + "}, cancellationToken);");
     }
 
     private static void EmitConfirm(StringBuilder builder, PropertyMetadata property, string indent)
@@ -357,7 +357,7 @@ private static void EmitConfirm(StringBuilder builder, PropertyMetadata property
         builder.AppendLine(indent + "{");
         builder.AppendLine(indent + "    options.Message = " + Quote(property.Message) + ";");
         builder.AppendLine(indent + "    options.DefaultValue = model." + property.Name + ";");
-        builder.AppendLine(indent + "});");
+        builder.AppendLine(indent + "}, cancellationToken);");
     }
 
     private static void EmitSelect(StringBuilder builder, PropertyMetadata property, string indent)
@@ -372,7 +372,7 @@ private static void EmitSelect(StringBuilder builder, PropertyMetadata property,
         }
 
         builder.AppendLine(indent + "    options.DefaultValue = model." + property.Name + ";");
-        builder.AppendLine(indent + "});");
+        builder.AppendLine(indent + "}, cancellationToken);");
     }
 
     private static void EmitMultiSelect(StringBuilder builder, PropertyMetadata property, string indent)
@@ -387,7 +387,7 @@ private static void EmitMultiSelect(StringBuilder builder, PropertyMetadata prop
         }
 
         builder.AppendLine(indent + "    options.DefaultValues = model." + property.Name + " ?? global::System.Array.Empty<" + property.TypeArg + ">();");
-        builder.AppendLine(indent + "});");
+        builder.AppendLine(indent + "}, cancellationToken);");
     }
 
     private static void EmitList(StringBuilder builder, PropertyMetadata property, string indent)
@@ -397,7 +397,7 @@ private static void EmitList(StringBuilder builder, PropertyMetadata property, s
         builder.AppendLine(indent + "    options.Message = " + Quote(property.Message) + ";");
         builder.AppendLine(indent + "    options.DefaultValues = model." + property.Name + " ?? global::System.Array.Empty<" + property.TypeArg + ">();");
         EmitValidators(builder, property, indent);
-        builder.AppendLine(indent + "});");
+        builder.AppendLine(indent + "}, cancellationToken);");
     }
 
     private static void EmitValidators(StringBuilder builder, PropertyMetadata property, string indent)

src/Sharprompt/Forms/FormBase.cs

@@ -2,6 +2,7 @@
 using System.Collections.Generic;
 using System.ComponentModel.DataAnnotations;
 using System.Diagnostics.CodeAnalysis;
+using System.Threading;
 
 using Sharprompt.Drivers;
 using Sharprompt.Internal;
@@ -26,6 +27,8 @@ [new ConsoleKeyBinding(ConsoleKey.Escape)] = HandleEscape
         };
     }
 
+    private static readonly TimeSpan s_keyPollingInterval = TimeSpan.FromMilliseconds(16);
+
     private readonly IConsoleDriver _consoleDriver;
     private readonly FormRenderer _formRenderer;
     private readonly PromptConfiguration _configuration;
@@ -42,13 +45,15 @@ [new ConsoleKeyBinding(ConsoleKey.Escape)] = HandleEscape
 
     public void Dispose() => _consoleDriver.Dispose();
 
-    public T Start()
+    public T Start(CancellationToken cancellationToken = default)
     {
+        cancellationToken.ThrowIfCancellationRequested();
+
         while (true)
         {
             _formRenderer.Render(InputTemplate);
 
-            if (!TryGetResult(out var result))
+            if (!TryGetResult(cancellationToken, out var result))
             {
                 continue;
             }
@@ -97,11 +102,11 @@ protected bool TryValidate([NotNullWhen(true)] object? input, IList<Func<object?
         return true;
     }
 
-    private bool TryGetResult([NotNullWhen(true)] out T? result)
+    private bool TryGetResult(CancellationToken cancellationToken, [NotNullWhen(true)] out T? result)
     {
         do
         {
-            var keyInfo = _consoleDriver.ReadKey();
+            var keyInfo = ReadKey(cancellationToken);
 
             if (keyInfo.Key == ConsoleKey.Enter)
             {
@@ -131,6 +136,28 @@ private bool TryGetResult([NotNullWhen(true)] out T? result)
         return false;
     }
 
+    private ConsoleKeyInfo ReadKey(CancellationToken cancellationToken)
+    {
+        // ReadKey blocks and cannot be interrupted, so when the token can be canceled
+        // poll for available input while waiting on the token instead.
+        while (true)
+        {
+            if (cancellationToken.IsCancellationRequested)
+            {
+                _formRenderer.Cancel();
+
+                throw new OperationCanceledException(Resource.Message_PromptCanceled, cancellationToken);
+            }
+
+            if (!cancellationToken.CanBeCanceled || _consoleDriver.KeyAvailable)
+            {
+                return _consoleDriver.ReadKey();
+            }
+
+            cancellationToken.WaitHandle.WaitOne(s_keyPollingInterval);
+        }
+    }
+
     private void CancellationHandler()
     {
         _formRenderer.Cancel();

src/Sharprompt/ModelBinderRegistry.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Concurrent;
+using System.Threading;
 
 namespace Sharprompt;
 
@@ -9,14 +10,23 @@ public static class ModelBinderRegistry
 
     public static void Register<T>(Action<T> binder) where T : notnull
     {
+        ArgumentNullException.ThrowIfNull(binder);
+
+        Register<T>((model, _) => binder(model));
+    }
+
+    public static void Register<T>(Action<T, CancellationToken> binder) where T : notnull
+    {
+        ArgumentNullException.ThrowIfNull(binder);
+
         s_binders[typeof(T)] = binder;
     }
 
-    internal static bool TryGetBinder<T>(out Action<T>? binder) where T : notnull
+    internal static bool TryGetBinder<T>(out Action<T, CancellationToken>? binder) where T : notnull
     {
         if (s_binders.TryGetValue(typeof(T), out var obj))
         {
-            binder = (Action<T>)obj;
+            binder = (Action<T, CancellationToken>)obj;
             return true;
         }