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.

2 files changed, 20 insertions, 6 deletions

diff --git a/src/WixToolset.Extensibility/Services/IWixtoolsetCoreServiceProvider.cs b/src/WixToolset.Extensibility/Services/IWixtoolsetCoreServiceProvider.cs
index 2d0450dc..f5fb28fb 100644
--- a/src/WixToolset.Extensibility/Services/IWixtoolsetCoreServiceProvider.cs
+++ b/src/WixToolset.Extensibility/Services/IWixtoolsetCoreServiceProvider.cs
@@ -8,7 +8,7 @@ namespace WixToolset.Extensibility.Services
     /// <summary>
     /// The core of the service provider used to add services to the service provider.
     /// </summary>
-    public interface IWixToolsetCoreServiceProvider : IWixToolsetServiceProvider
+    public interface IWixToolsetCoreServiceProvider : IServiceProvider
     {
         /// <summary>
         /// Adds a service to the service locator.
diff --git a/src/WixToolset.Extensibility/Services/IWixToolsetServiceProvider.cs b/src/WixToolset.Extensibility/Services/ServiceProviderExtensions.cs
index 0315f7ed..68484d09 100644
--- a/src/WixToolset.Extensibility/Services/IWixToolsetServiceProvider.cs
+++ b/src/WixToolset.Extensibility/Services/ServiceProviderExtensions.cs
@@ -5,30 +5,44 @@ namespace WixToolset.Extensibility.Services
     using System;
 
     /// <summary>
-    /// Service provider.
+    /// Service provider extensions.
     /// </summary>
-    public interface IWixToolsetServiceProvider : IServiceProvider
+    public static class ServiceProviderExtensions
     {
         /// <summary>
         /// Gets a service from the service provider.
         /// </summary>
         /// <typeparam name="T">Type of service to get.</typeparam>
-        T GetService<T>() where T : class;
+        /// <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>
-        bool TryGetService(Type serviceType, out object service);
+        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>
-        bool TryGetService<T>(out T service) where T : class;
+        public static bool TryGetService<T>(this IServiceProvider provider, out T service) where T : class
+        {
+            service = provider.GetService(typeof(T)) as T;
+            return service != null;
+        }
     }
 }