Support cancellation of prompts

Closes #417

examples/Console/Prompt/Program.cs

@@ -25,7 +25,6 @@ namespace Spectre.Console.Examples
             var age = AskAge();
             var password = AskPassword();
             var color = AskColor();
-            var origin = AskOrigin();
 
             // Summary
             AnsiConsole.WriteLine();
@@ -38,8 +37,7 @@ namespace Spectre.Console.Examples
                 .AddRow("[grey]Favorite sport[/]", sport)
                 .AddRow("[grey]Age[/]", age.ToString())
                 .AddRow("[grey]Password[/]", password)
-                .AddRow("[grey]Favorite color[/]", string.IsNullOrEmpty(color) ? "Unknown" : color)
-                .AddRow("[grey]Origin[/]", origin));
+                .AddRow("[grey]Favorite color[/]", string.IsNullOrEmpty(color) ? "Unknown" : color));
         }
 
         private static string AskName()
@@ -143,14 +141,5 @@ namespace Spectre.Console.Examples
                 new TextPrompt<string>("[grey][[Optional]][/] What is your [green]favorite color[/]?")
                     .AllowEmpty());
         }
-
-        private static string AskOrigin()
-        {
-            AnsiConsole.WriteLine();
-            AnsiConsole.Render(new Rule("[yellow]Default answer[/]").RuleStyle("grey").LeftAligned());
-            var name = AnsiConsole.Ask("Where are you [green]from[/]?", "Earth");
-            return name;
-        }
-
     }
 }

src/.editorconfig

@@ -92,4 +92,10 @@ dotnet_diagnostic.IDE0004.severity = warning
 dotnet_diagnostic.CA1810.severity = none
 
 # IDE0044: Add readonly modifier
-dotnet_diagnostic.IDE0044.severity = warning
+dotnet_diagnostic.IDE0044.severity = warning
+
+# RCS1047: Non-asynchronous method name should not end with 'Async'.
+dotnet_diagnostic.RCS1047.severity = none
+
+# RCS1090: Call 'ConfigureAwait(false)'.
+dotnet_diagnostic.RCS1090.severity = warning

src/Spectre.Console.Testing/Internal/NoopExclusivityMode.cs

@@ -12,7 +12,7 @@ namespace Spectre.Console.Testing
 
         public async Task<T> Run<T>(Func<Task<T>> func)
         {
-            return await func();
+            return await func().ConfigureAwait(false);
         }
     }
 }

src/Spectre.Console.Testing/TestConsoleInput.cs

@@ -1,5 +1,7 @@
 using System;
 using System.Collections.Generic;
+using System.Threading;
+using System.Threading.Tasks;
 
 namespace Spectre.Console.Testing
 {
@@ -74,5 +76,11 @@ namespace Spectre.Console.Testing
 
             return _input.Dequeue();
         }
+
+        /// <inheritdoc/>
+        public Task<ConsoleKeyInfo?> ReadKeyAsync(bool intercept, CancellationToken cancellationToken)
+        {
+            return Task.FromResult(ReadKey(intercept));
+        }
     }
 }

src/Spectre.Console/Cli/Internal/CommandExecutor.cs

@@ -81,7 +81,7 @@ namespace Spectre.Console.Cli
                 var context = new CommandContext(parsedResult.Remaining, leaf.Command.Name, leaf.Command.Data);
 
                 // Execute the command tree.
-                return await Execute(leaf, parsedResult.Tree, context, resolver, configuration);
+                return await Execute(leaf, parsedResult.Tree, context, resolver, configuration).ConfigureAwait(false);
             }
         }
 

src/Spectre.Console/Extensions/AnsiConsoleExtensions.Input.cs

@@ -2,6 +2,8 @@ using System;
 using System.Collections.Generic;
 using System.Globalization;
 using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
 
 namespace Spectre.Console
 {
@@ -10,7 +12,7 @@ namespace Spectre.Console
     /// </summary>
     public static partial class AnsiConsoleExtensions
     {
-        internal static string ReadLine(this IAnsiConsole console, Style? style, bool secret, IEnumerable<string>? items = null)
+        internal static async Task<string> ReadLine(this IAnsiConsole console, Style? style, bool secret, IEnumerable<string>? items = null, CancellationToken cancellationToken = default)
         {
             if (console is null)
             {
@@ -24,7 +26,7 @@ namespace Spectre.Console
 
             while (true)
             {
-                var rawKey = console.Input.ReadKey(true);
+                var rawKey = await console.Input.ReadKeyAsync(true, cancellationToken).ConfigureAwait(false);
                 if (rawKey == null)
                 {
                     continue;

src/Spectre.Console/IAnsiConsoleInput.cs

@@ -1,4 +1,6 @@
 using System;
+using System.Threading;
+using System.Threading.Tasks;
 
 namespace Spectre.Console
 {
@@ -13,5 +15,13 @@ namespace Spectre.Console
         /// <param name="intercept">Whether or not to intercept the key.</param>
         /// <returns>The key that was read.</returns>
         ConsoleKeyInfo? ReadKey(bool intercept);
+
+        /// <summary>
+        /// Reads a key from the console.
+        /// </summary>
+        /// <param name="intercept">Whether or not to intercept the key.</param>
+        /// <param name="cancellationToken">The token to monitor for cancellation requests.</param>
+        /// <returns>The key that was read.</returns>
+        Task<ConsoleKeyInfo?> ReadKeyAsync(bool intercept, CancellationToken cancellationToken);
     }
 }

src/Spectre.Console/Internal/DefaultExclusivityMode.cs

@@ -46,7 +46,7 @@ namespace Spectre.Console.Internal
 
             try
             {
-                return await func();
+                return await func().ConfigureAwait(false);
             }
             finally
             {

src/Spectre.Console/Internal/DefaultInput.cs

@@ -1,4 +1,6 @@
 using System;
+using System.Threading;
+using System.Threading.Tasks;
 
 namespace Spectre.Console
 {
@@ -18,7 +20,32 @@ namespace Spectre.Console
                 throw new InvalidOperationException("Failed to read input in non-interactive mode.");
             }
 
+            if (!System.Console.KeyAvailable)
+            {
+                return null;
+            }
+
             return System.Console.ReadKey(intercept);
         }
+
+        public async Task<ConsoleKeyInfo?> ReadKeyAsync(bool intercept, CancellationToken cancellationToken)
+        {
+            while (true)
+            {
+                if (cancellationToken.IsCancellationRequested)
+                {
+                    return null;
+                }
+
+                if (System.Console.KeyAvailable)
+                {
+                    break;
+                }
+
+                await Task.Delay(5, cancellationToken).ConfigureAwait(false);
+            }
+
+            return ReadKey(intercept);
+        }
     }
 }

src/Spectre.Console/Widgets/Prompt/ConfirmationPrompt.cs

@@ -1,3 +1,6 @@
+using System.Threading;
+using System.Threading.Tasks;
+
 namespace Spectre.Console
 {
     /// <summary>
@@ -50,6 +53,12 @@ namespace Spectre.Console
 
         /// <inheritdoc/>
         public bool Show(IAnsiConsole console)
+        {
+            return ShowAsync(console, CancellationToken.None).GetAwaiter().GetResult();
+        }
+
+        /// <inheritdoc/>
+        public async Task<bool> ShowAsync(IAnsiConsole console, CancellationToken cancellationToken)
         {
             var prompt = new TextPrompt<char>(_prompt)
                 .InvalidChoiceMessage(InvalidChoiceMessage)
@@ -60,7 +69,7 @@ namespace Spectre.Console
                 .AddChoice(Yes)
                 .AddChoice(No);
 
-            var result = prompt.Show(console);
+            var result = await prompt.ShowAsync(console, cancellationToken).ConfigureAwait(false);
             return result == Yes;
         }
     }

src/Spectre.Console/Widgets/Prompt/IPrompt.cs

@@ -1,3 +1,6 @@
+using System.Threading;
+using System.Threading.Tasks;
+
 namespace Spectre.Console
 {
     /// <summary>
@@ -12,5 +15,13 @@ namespace Spectre.Console
         /// <param name="console">The console.</param>
         /// <returns>The prompt input result.</returns>
         T Show(IAnsiConsole console);
+
+        /// <summary>
+        /// Shows the prompt asynchronously.
+        /// </summary>
+        /// <param name="console">The console.</param>
+        /// <param name="cancellationToken">The token to monitor for cancellation requests.</param>
+        /// <returns>The prompt input result.</returns>
+        Task<T> ShowAsync(IAnsiConsole console, CancellationToken cancellationToken);
     }
 }

src/Spectre.Console/Widgets/Prompt/List/ListPrompt.cs

@@ -1,5 +1,7 @@
 using System;
 using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
 using Spectre.Console.Rendering;
 
 namespace Spectre.Console
@@ -16,7 +18,10 @@ namespace Spectre.Console
             _strategy = strategy ?? throw new ArgumentNullException(nameof(strategy));
         }
 
-        public ListPromptState<T> Show(ListPromptTree<T> tree, int requestedPageSize = 15)
+        public async Task<ListPromptState<T>> Show(
+            ListPromptTree<T> tree,
+            CancellationToken cancellationToken,
+            int requestedPageSize = 15)
         {
             if (tree is null)
             {
@@ -48,7 +53,7 @@ namespace Spectre.Console
 
                 while (true)
                 {
-                    var rawKey = _console.Input.ReadKey(true);
+                    var rawKey = await _console.Input.ReadKeyAsync(true, cancellationToken).ConfigureAwait(false);
                     if (rawKey == null)
                     {
                         continue;

src/Spectre.Console/Widgets/Prompt/MultiSelectionPrompt.cs

@@ -2,6 +2,8 @@ using System;
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
 using Spectre.Console.Rendering;
 
 namespace Spectre.Console
@@ -85,10 +87,16 @@ namespace Spectre.Console
 
         /// <inheritdoc/>
         public List<T> Show(IAnsiConsole console)
+        {
+            return ShowAsync(console, CancellationToken.None).GetAwaiter().GetResult();
+        }
+
+        /// <inheritdoc/>
+        public async Task<List<T>> ShowAsync(IAnsiConsole console, CancellationToken cancellationToken)
         {
             // Create the list prompt
             var prompt = new ListPrompt<T>(console, this);
-            var result = prompt.Show(Tree, PageSize);
+            var result = await prompt.Show(Tree, cancellationToken, PageSize).ConfigureAwait(false);
 
             if (Mode == SelectionMode.Leaf)
             {

src/Spectre.Console/Widgets/Prompt/SelectionPrompt.cs

@@ -1,6 +1,8 @@
 using System;
 using System.Collections.Generic;
 using System.ComponentModel;
+using System.Threading;
+using System.Threading.Tasks;
 using Spectre.Console.Rendering;
 
 namespace Spectre.Console
@@ -74,10 +76,16 @@ namespace Spectre.Console
 
         /// <inheritdoc/>
         public T Show(IAnsiConsole console)
+        {
+            return ShowAsync(console, CancellationToken.None).GetAwaiter().GetResult();
+        }
+
+        /// <inheritdoc/>
+        public async Task<T> ShowAsync(IAnsiConsole console, CancellationToken cancellationToken)
         {
             // Create the list prompt
             var prompt = new ListPrompt<T>(console, this);
-            var result = prompt.Show(_tree, PageSize);
+            var result = await prompt.Show(_tree, cancellationToken, PageSize).ConfigureAwait(false);
 
             // Return the selected item
             return result.Items[result.Index].Data;

src/Spectre.Console/Widgets/Prompt/TextPrompt.cs

@@ -5,6 +5,8 @@ using System.Diagnostics.CodeAnalysis;
 using System.Globalization;
 using System.Linq;
 using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
 
 namespace Spectre.Console
 {
@@ -94,13 +96,19 @@ namespace Spectre.Console
         /// <returns>The user input converted to the expected type.</returns>
         /// <inheritdoc/>
         public T Show(IAnsiConsole console)
+        {
+            return ShowAsync(console, CancellationToken.None).GetAwaiter().GetResult();
+        }
+
+        /// <inheritdoc/>
+        public async Task<T> ShowAsync(IAnsiConsole console, CancellationToken cancellationToken)
         {
             if (console is null)
             {
                 throw new ArgumentNullException(nameof(console));
             }
 
-            return console.RunExclusive(() =>
+            return await console.RunExclusive(async () =>
             {
                 var promptStyle = PromptStyle ?? Style.Plain;
                 var converter = Converter ?? TypeConverterHelper.ConvertToString;
@@ -111,7 +119,7 @@ namespace Spectre.Console
 
                 while (true)
                 {
-                    var input = console.ReadLine(promptStyle, IsSecret, choices);
+                    var input = await console.ReadLine(promptStyle, IsSecret, choices, cancellationToken).ConfigureAwait(false);
 
                     // Nothing entered?
                     if (string.IsNullOrWhiteSpace(input))
@@ -162,7 +170,7 @@ namespace Spectre.Console
 
                     return result;
                 }
-            });
+            }).ConfigureAwait(false);
         }
 
         /// <summary>