8 files changed, 47 insertions, 25 deletions
diff --git a/src/api/burn/WixToolset.BootstrapperCore.Native/inc/BootstrapperApplication.h b/src/api/burn/WixToolset.BootstrapperCore.Native/inc/BootstrapperApplication.h
index e5f924c8..c2641b5f 100644
--- a/src/api/burn/WixToolset.BootstrapperCore.Native/inc/BootstrapperApplication.h
+++ b/src/api/burn/WixToolset.BootstrapperCore.Native/inc/BootstrapperApplication.h
@@ -38,6 +38,13 @@ enum BOOTSTRAPPER_ERROR_TYPE
    BOOTSTRAPPER_ERROR_TYPE_APPLY,              // error occurred during apply.
 };
+enum BOOTSTRAPPER_FILES_IN_USE_TYPE
+{
+    BOOTSTRAPPER_FILES_IN_USE_TYPE_MSI,    // INSTALLMESSAGE_FILESINUSE
+    BOOTSTRAPPER_FILES_IN_USE_TYPE_MSI_RM, // INSTALLMESSAGE_RMFILESINUSE
+    BOOTSTRAPPER_FILES_IN_USE_TYPE_NETFX,  // MMIO_CLOSE_APPS
+};
 enum BOOTSTRAPPER_RELATED_OPERATION
 {
    BOOTSTRAPPER_RELATED_OPERATION_NONE,
@@ -874,6 +881,7 @@ struct BA_ONEXECUTEFILESINUSE_ARGS
    DWORD cFiles;
    LPCWSTR* rgwzFiles;
    int nRecommendation;
+    BOOTSTRAPPER_FILES_IN_USE_TYPE source;
 };
 struct BA_ONEXECUTEFILESINUSE_RESULTS
diff --git a/src/api/burn/WixToolset.Mba.Core/BootstrapperApplication.cs b/src/api/burn/WixToolset.Mba.Core/BootstrapperApplication.cs
index a78bf43f..b1fcaea4 100644
--- a/src/api/burn/WixToolset.Mba.Core/BootstrapperApplication.cs
+++ b/src/api/burn/WixToolset.Mba.Core/BootstrapperApplication.cs
@@ -1712,9 +1712,9 @@ namespace WixToolset.Mba.Core
            return args.HResult;
        }
-        int IBootstrapperApplication.OnExecuteFilesInUse(string wzPackageId, int cFiles, string[] rgwzFiles, Result nRecommendation, ref Result pResult)
+        int IBootstrapperApplication.OnExecuteFilesInUse(string wzPackageId, int cFiles, string[] rgwzFiles, Result nRecommendation, FilesInUseType source, ref Result pResult)
        {
-            ExecuteFilesInUseEventArgs args = new ExecuteFilesInUseEventArgs(wzPackageId, rgwzFiles, nRecommendation, pResult);
+            ExecuteFilesInUseEventArgs args = new ExecuteFilesInUseEventArgs(wzPackageId, rgwzFiles, nRecommendation, source, pResult);
            this.OnExecuteFilesInUse(args);
            pResult = args.Result;
diff --git a/src/api/burn/WixToolset.Mba.Core/EventArgs.cs b/src/api/burn/WixToolset.Mba.Core/EventArgs.cs
index 55c9e74c..65169b25 100644
--- a/src/api/burn/WixToolset.Mba.Core/EventArgs.cs
+++ b/src/api/burn/WixToolset.Mba.Core/EventArgs.cs
@@ -1613,11 +1613,12 @@ namespace WixToolset.Mba.Core
    public class ExecuteFilesInUseEventArgs : ResultEventArgs
    {
        /// <summary />
-        public ExecuteFilesInUseEventArgs(string packageId, string[] files, Result recommendation, Result result)
+        public ExecuteFilesInUseEventArgs(string packageId, string[] files, Result recommendation, FilesInUseType source, Result result)
            : base(recommendation, result)
        {
            this.PackageId = packageId;
            this.Files = new ReadOnlyCollection<string>(files ?? new string[] { });
+            this.Source = source;
        }
        /// <summary>
@@ -1629,6 +1630,11 @@ namespace WixToolset.Mba.Core
        /// Gets the list of files in use.
        /// </summary>
        public IList<string> Files { get; private set; }
+        /// <summary>
+        /// Gets the source of the message.
+        /// </summary>
+        public FilesInUseType Source { get; private set; }
    }
    /// <summary>
diff --git a/src/api/burn/WixToolset.Mba.Core/IBootstrapperApplication.cs b/src/api/burn/WixToolset.Mba.Core/IBootstrapperApplication.cs
index c6a8fc14..3df54bde 100644
--- a/src/api/burn/WixToolset.Mba.Core/IBootstrapperApplication.cs
+++ b/src/api/burn/WixToolset.Mba.Core/IBootstrapperApplication.cs
@@ -777,12 +777,6 @@ namespace WixToolset.Mba.Core
        /// <summary>
        /// See <see cref="IDefaultBootstrapperApplication.ExecuteFilesInUse"/>.
        /// </summary>
-        /// <param name="wzPackageId"></param>
-        /// <param name="cFiles"></param>
-        /// <param name="rgwzFiles"></param>
-        /// <param name="nRecommendation"></param>
-        /// <param name="pResult"></param>
-        /// <returns></returns>
        [PreserveSig]
        [return: MarshalAs(UnmanagedType.I4)]
        int OnExecuteFilesInUse(
@@ -790,6 +784,7 @@ namespace WixToolset.Mba.Core
            [MarshalAs(UnmanagedType.U4)] int cFiles,
            [MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 1, ArraySubType = UnmanagedType.LPWStr), In] string[] rgwzFiles,
            [MarshalAs(UnmanagedType.I4)] Result nRecommendation,
+            [MarshalAs(UnmanagedType.I4)] FilesInUseType source,
            [MarshalAs(UnmanagedType.I4)] ref Result pResult
            );
@@ -1446,6 +1441,25 @@ namespace WixToolset.Mba.Core
    };
    /// <summary>
+    /// Indicates the source of the FilesInUse message.
+    /// </summary>
+    public enum FilesInUseType
+    {
+        /// <summary>
+        /// Generated from INSTALLMESSAGE_FILESINUSE.
+        /// </summary>
+        Msi,
+        /// <summary>
+        /// Generated from INSTALLMESSAGE_RMFILESINUSE.
+        /// </summary>
+        MsiRm,
+        /// <summary>
+        /// Generated from MMIO_CLOSE_APPS.
+        /// </summary>
+        Netfx,
+    }
+    /// <summary>
    /// The calculated operation for the related bundle.
    /// </summary>
    public enum RelatedOperation
diff --git a/src/api/burn/balutil/inc/BalBaseBAFunctions.h b/src/api/burn/balutil/inc/BalBaseBAFunctions.h
index 8d9bddca..7f52f76e 100644
--- a/src/api/burn/balutil/inc/BalBaseBAFunctions.h
+++ b/src/api/burn/balutil/inc/BalBaseBAFunctions.h
@@ -583,6 +583,7 @@ public: // IBootstrapperApplication
        __in DWORD /*cFiles*/,
        __in_ecount_z(cFiles) LPCWSTR* /*rgwzFiles*/,
        __in int /*nRecommendation*/,
+        __in BOOTSTRAPPER_FILES_IN_USE_TYPE /*source*/,
        __inout int* /*pResult*/
        )
    {
diff --git a/src/api/burn/balutil/inc/BalBaseBootstrapperApplication.h b/src/api/burn/balutil/inc/BalBaseBootstrapperApplication.h
index 4d043dfe..5665fee3 100644
--- a/src/api/burn/balutil/inc/BalBaseBootstrapperApplication.h
+++ b/src/api/burn/balutil/inc/BalBaseBootstrapperApplication.h
@@ -738,6 +738,7 @@ public: // IBootstrapperApplication
        __in DWORD /*cFiles*/,
        __in_ecount_z(cFiles) LPCWSTR* /*rgwzFiles*/,
        __in int /*nRecommendation*/,
+        __in BOOTSTRAPPER_FILES_IN_USE_TYPE /*source*/,
        __inout int* pResult
        )
    {
diff --git a/src/api/burn/balutil/inc/BalBaseBootstrapperApplicationProc.h b/src/api/burn/balutil/inc/BalBaseBootstrapperApplicationProc.h
index 59bfc1f8..2292cd64 100644
--- a/src/api/burn/balutil/inc/BalBaseBootstrapperApplicationProc.h
+++ b/src/api/burn/balutil/inc/BalBaseBootstrapperApplicationProc.h
@@ -438,7 +438,7 @@ static HRESULT BalBaseBAProcOnExecuteFilesInUse(
    __inout BA_ONEXECUTEFILESINUSE_RESULTS* pResults
    )
 {
-    return pBA->OnExecuteFilesInUse(pArgs->wzPackageId, pArgs->cFiles, pArgs->rgwzFiles, pArgs->nRecommendation, &pResults->nResult);
+    return pBA->OnExecuteFilesInUse(pArgs->wzPackageId, pArgs->cFiles, pArgs->rgwzFiles, pArgs->nRecommendation, pArgs->source, &pResults->nResult);
 }
 static HRESULT BalBaseBAProcOnExecutePackageComplete(
diff --git a/src/api/burn/balutil/inc/IBootstrapperApplication.h b/src/api/burn/balutil/inc/IBootstrapperApplication.h
index be9b7b6e..2ba1f503 100644
--- a/src/api/burn/balutil/inc/IBootstrapperApplication.h
+++ b/src/api/burn/balutil/inc/IBootstrapperApplication.h
@@ -488,27 +488,19 @@ DECLARE_INTERFACE_IID_(IBootstrapperApplication, IUnknown, "53C31D56-49C0-426B-A
        __inout int* pResult
        ) = 0;
-    // OnExecuteFilesInUse - called when the engine encounters files in use while
+    // OnExecuteFilesInUse - called when the engine receives a files in use message
-    //                       executing a package.
+    //                       while executing a package.
    //
-    // Return:
+    // Return value depends on the source:
-    //  IDOK instructs the engine to let the Restart Manager attempt to close the
+    //  BOOTSTRAPPER_FILES_IN_USE_TYPE_MSI: https://docs.microsoft.com/en-us/windows/win32/msi/installvalidate-action
-    //       applications to avoid a restart.
+    //  BOOTSTRAPPER_FILES_IN_USE_TYPE_MSI_RM: https://docs.microsoft.com/en-us/windows/win32/msi/using-restart-manager-with-an-external-ui-
-    //
+    //  BOOTSTRAPPER_FILES_IN_USE_TYPE_NETFX: https://docs.microsoft.com/en-us/dotnet/framework/deployment/how-to-get-progress-from-the-dotnet-installer
-    //  IDCANCEL instructs the engine to abort the execution and start rollback.
-    //
-    //  IDIGNORE instructs the engine to ignore the running applications. A restart will be
-    //           required.
-    //
-    //  IDRETRY instructs the engine to check if the applications are still running again.
-    //
-    //  IDNOACTION is equivalent to ignoring the running applications. A restart will be
-    //             required.
    STDMETHOD(OnExecuteFilesInUse)(
        __in_z LPCWSTR wzPackageId,
        __in DWORD cFiles,
        __in_ecount_z(cFiles) LPCWSTR* rgwzFiles,
        __in int nRecommendation,
+        __in BOOTSTRAPPER_FILES_IN_USE_TYPE source,
        __inout int* pResult
        ) = 0;