4 files changed, 37 insertions, 2 deletions

diff --git a/src/WixToolset.Extensibility/BasePreprocessorExtension.cs b/src/WixToolset.Extensibility/BasePreprocessorExtension.cs
index b7d29095..cfacf97a 100644
--- a/src/WixToolset.Extensibility/BasePreprocessorExtension.cs
+++ b/src/WixToolset.Extensibility/BasePreprocessorExtension.cs
@@ -85,7 +85,7 @@ namespace WixToolset.Extensibility
         /// <summary>
         /// Called at the end of the preprocessing of a source file.
         /// </summary>
-        public virtual void PostPreprocess(XDocument document)
+        public virtual void PostPreprocess(IPreprocessResult result)
         {
         }
     }
diff --git a/src/WixToolset.Extensibility/Data/IIncludedFile.cs b/src/WixToolset.Extensibility/Data/IIncludedFile.cs
new file mode 100644
index 00000000..ac5e604c
--- /dev/null
+++ b/src/WixToolset.Extensibility/Data/IIncludedFile.cs
@@ -0,0 +1,21 @@
+// 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.Data
+{
+    using WixToolset.Data;
+
+    public interface IIncludedFile
+    {
+        /// <summary>
+        /// Gets the full path of the included file.
+        /// </summary>
+        /// <value>The full path of the included file.</value>
+        string Path { get; set; }
+
+        /// <summary>
+        /// Gets the source line numbers.
+        /// </summary>
+        /// <value>The source line numbers.</value>
+        SourceLineNumber SourceLineNumbers { get; set; }
+    }
+}
diff --git a/src/WixToolset.Extensibility/Data/IPreprocessResult.cs b/src/WixToolset.Extensibility/Data/IPreprocessResult.cs
new file mode 100644
index 00000000..955c0ced
--- /dev/null
+++ b/src/WixToolset.Extensibility/Data/IPreprocessResult.cs
@@ -0,0 +1,14 @@
+// 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.Data
+{
+    using System.Collections.Generic;
+    using System.Xml.Linq;
+
+    public interface IPreprocessResult
+    {
+        XDocument Document { get; set; }
+
+        IEnumerable<IIncludedFile> IncludedFiles { get; set; }
+    }
+}
diff --git a/src/WixToolset.Extensibility/IPreprocessorExtension.cs b/src/WixToolset.Extensibility/IPreprocessorExtension.cs
index 7eb8584f..94eb7d78 100644
--- a/src/WixToolset.Extensibility/IPreprocessorExtension.cs
+++ b/src/WixToolset.Extensibility/IPreprocessorExtension.cs
@@ -53,6 +53,6 @@ namespace WixToolset.Extensibility
         /// <summary>
         /// Called at the end of the preprocessing of a source file.
         /// </summary>
-        void PostPreprocess(XDocument document);
+        void PostPreprocess(IPreprocessResult result);
     }
 }