Use extension methods instead of a custom interface for IServiceProvider

There are several helpful methods for getting services out of an
IServiceProvider. Instead of introducing a custom interface to inject
those methods into the inheritance tree, this change uses extension
methods to add the helper methods and reduce the number of custom
interfaces.

1 files changed, 48 insertions, 0 deletions

diff --git a/src/WixToolset.Extensibility/Services/ServiceProviderExtensions.cs b/src/WixToolset.Extensibility/Services/ServiceProviderExtensions.cs
new file mode 100644
index 00000000..68484d09
--- /dev/null
+++ b/src/WixToolset.Extensibility/Services/ServiceProviderExtensions.cs
@@ -0,0 +1,48 @@
+// Copyright (c) .NET Foundation and contributors. All rights reserved. Licensed under the Microsoft Reciprocal License. See LICENSE.TXT file in the project root for full license information.
+
+namespace WixToolset.Extensibility.Services
+{
+    using System;
+
+    /// <summary>
+    /// Service provider extensions.
+    /// </summary>
+    public static class ServiceProviderExtensions
+    {
+        /// <summary>
+        /// Gets a service from the service provider.
+        /// </summary>
+        /// <typeparam name="T">Type of service to get.</typeparam>
+        /// <param name="provider">Service provider.</param>
+        public static T GetService<T>(this IServiceProvider provider) where T : class
+        {
+            return provider.GetService(typeof(T)) as T;
+        }
+
+        /// <summary>
+        /// Gets a service from the service provider.
+        /// </summary>
+        /// <param name="provider">Service provider.</param>
+        /// <param name="serviceType">Type of service to get.</param>
+        /// <param name="service">Retrieved service.</param>
+        /// <returns>True if the service was found, otherwise false</returns>
+        public static bool TryGetService(this IServiceProvider provider, Type serviceType, out object service)
+        {
+            service = provider.GetService(serviceType);
+            return service != null;
+        }
+
+        /// <summary>
+        /// Gets a service from the service provider.
+        /// </summary>
+        /// <typeparam name="T">Type of service to get.</typeparam>
+        /// <param name="provider">Service provider.</param>
+        /// <param name="service">Retrieved service.</param>
+        /// <returns>True if the service was found, otherwise false</returns>
+        public static bool TryGetService<T>(this IServiceProvider provider, out T service) where T : class
+        {
+            service = provider.GetService(typeof(T)) as T;
+            return service != null;
+        }
+    }
+}