Add the possibility to register multiple interceptors (#1412)

Having the interceptors registered with the ITypeRegistrar also enables the usage of ITypeResolver in interceptors.

src/Spectre.Console.Cli/ConfiguratorExtensions.cs

@@ -229,7 +229,7 @@ public static class ConfiguratorExtensions
             throw new ArgumentNullException(nameof(configurator));
         }
 
-        configurator.Settings.Interceptor = interceptor;
+        configurator.Settings.Registrar.RegisterInstance<ICommandInterceptor>(interceptor);
         return configurator;
     }
 

src/Spectre.Console.Cli/ICommandAppSettings.cs

@@ -50,6 +50,7 @@ public interface ICommandAppSettings
     /// Gets or sets the <see cref="ICommandInterceptor"/> used
     /// to intercept settings before it's being sent to the command.
     /// </summary>
+    [Obsolete("Register the interceptor with the ITypeRegistrar.")]
     ICommandInterceptor? Interceptor { get; set; }
 
     /// <summary>

src/Spectre.Console.Cli/ICommandInterceptor.cs

@@ -12,5 +12,25 @@ public interface ICommandInterceptor
     /// </summary>
     /// <param name="context">The intercepted <see cref="CommandContext"/>.</param>
     /// <param name="settings">The intercepted <see cref="CommandSettings"/>.</param>
-    void Intercept(CommandContext context, CommandSettings settings);
+    void Intercept(CommandContext context, CommandSettings settings)
+#if NETSTANDARD2_0
+    ;
+#else
+    {
+    }
+#endif
+
+    /// <summary>
+    /// Intercepts a command result before it's passed as the result.
+    /// </summary>
+    /// <param name="context">The intercepted <see cref="CommandContext"/>.</param>
+    /// <param name="settings">The intercepted <see cref="CommandSettings"/>.</param>
+    /// <param name="result">The result from the command execution.</param>
+    void InterceptResult(CommandContext context, CommandSettings settings, ref int result)
+#if NETSTANDARD2_0
+    ;
+#else
+    {
+    }
+#endif
 }

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

@@ -121,7 +121,7 @@ internal sealed class CommandExecutor
             VersionHelper.GetVersion(Assembly.GetEntryAssembly());
     }
 
-    private static Task<int> Execute(
+    private static async Task<int> Execute(
         CommandTree leaf,
         CommandTree tree,
         CommandContext context,
@@ -130,7 +130,19 @@ internal sealed class CommandExecutor
     {
         // Bind the command tree against the settings.
         var settings = CommandBinder.Bind(tree, leaf.Command.SettingsType, resolver);
-        configuration.Settings.Interceptor?.Intercept(context, settings);
+        var interceptors =
+            ((IEnumerable<ICommandInterceptor>?)resolver.Resolve(typeof(IEnumerable<ICommandInterceptor>))
+            ?? Array.Empty<ICommandInterceptor>()).ToList();
+#pragma warning disable CS0618 // Type or member is obsolete
+        if (configuration.Settings.Interceptor != null)
+        {
+            interceptors.Add(configuration.Settings.Interceptor);
+        }
+#pragma warning restore CS0618 // Type or member is obsolete
+        foreach (var interceptor in interceptors)
+        {
+            interceptor.Intercept(context, settings);
+        }
 
         // Create and validate the command.
         var command = leaf.CreateCommand(resolver);
@@ -141,6 +153,12 @@ internal sealed class CommandExecutor
         }
 
         // Execute the command.
-        return command.Execute(context, settings);
+        var result = await command.Execute(context, settings);
+        foreach (var interceptor in interceptors)
+        {
+            interceptor.InterceptResult(context, settings, ref result);
+        }
+
+        return result;
     }
 }

src/Spectre.Console.Cli/Internal/Configuration/CommandAppSettings.cs

@@ -8,6 +8,7 @@ internal sealed class CommandAppSettings : ICommandAppSettings
     public int MaximumIndirectExamples { get; set; }
     public bool ShowOptionDefaultValues { get; set; }
     public IAnsiConsole? Console { get; set; }
+    [Obsolete("Register the interceptor with the ITypeRegistrar.")]
     public ICommandInterceptor? Interceptor { get; set; }
     public ITypeRegistrarFrontend Registrar { get; set; }
     public CaseSensitivity CaseSensitivity { get; set; }

src/Spectre.Console.Testing/Cli/CallbackCommandInterceptor.cs

@@ -21,4 +21,11 @@ public sealed class CallbackCommandInterceptor : ICommandInterceptor
     {
         _callback(context, settings);
     }
+
+#if NETSTANDARD2_0
+    /// <inheritdoc/>
+    public void InterceptResult(CommandContext context, CommandSettings settings, ref int result)
+    {
+    }
+#endif
 }