1 files changed, 71 insertions, 0 deletions

diff --git a/src/WixToolset.Extensibility/BaseLibrarianExtension.cs b/src/WixToolset.Extensibility/BaseLibrarianExtension.cs
new file mode 100644
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+++ b/src/WixToolset.Extensibility/BaseLibrarianExtension.cs
@@ -0,0 +1,71 @@
+// 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
+{
+    using System.Collections.Generic;
+    using WixToolset.Data;
+    using WixToolset.Extensibility.Data;
+    using WixToolset.Extensibility.Services;
+
+    /// <summary>
+    /// Base class for creating a librarian extension.
+    /// </summary>
+    public abstract class BaseLibrarianExtension : ILibrarianExtension
+    {
+        /// <summary>
+        /// Context for use by the extension.
+        /// </summary>
+        protected ILibraryContext Context { get; private set; }
+
+        /// <summary>
+        /// Messaging for use by the extension.
+        /// </summary>
+        protected IMessaging Messaging { get; private set; }
+        
+        /// <summary>
+        /// Called at the beginning of combining.
+        /// </summary>
+        /// <param name="context">Librarian context.</param>
+        public virtual void PreCombine(ILibraryContext context)
+        {
+            this.Context = context;
+
+            this.Messaging = context.ServiceProvider.GetService<IMessaging>();
+        }
+
+        /// <summary>
+        /// Resolves a path to a file path on disk.
+        /// </summary>
+        /// <param name="sourceLineNumber">Source line number for the path to resolve.</param>
+        /// <param name="tupleDefinition">Tuple related to the path to resolve.</param>
+        /// <param name="path">Path to resolve.</param>
+        /// <returns>Optional resolved file result.</returns>
+        public virtual IResolveFileResult ResolveFile(SourceLineNumber sourceLineNumber, IntermediateTupleDefinition tupleDefinition, string path)
+        {
+            return null;
+        }
+
+        /// <summary>
+        /// Called at the end of combining.
+        /// </summary>
+        /// <param name="library">Combined library intermediate.</param>
+        public virtual void PostCombine(Intermediate library)
+        {
+        }
+
+        /// <summary>
+        /// Creates an IResolveFileResult.
+        /// </summary>
+        /// <param name="path">Optional resolved path to file.</param>
+        /// <param name="checkedPaths">Optional collection of paths checked for the file.</param>
+        /// <returns>Resolved file result.</returns>
+        protected IResolveFileResult CreateResolveFileResult(string path = null, IEnumerable<string> checkedPaths = null)
+        {
+            var result = this.Context.ServiceProvider.GetService<IResolveFileResult>();
+            result.Path = path;
+            result.CheckedPaths = checkedPaths;
+
+            return result;
+        }
+    }
+}