11 files changed, 114 insertions, 0 deletions

diff --git a/src/api/burn/WixToolset.BootstrapperCore.Native/inc/BootstrapperApplication.h b/src/api/burn/WixToolset.BootstrapperCore.Native/inc/BootstrapperApplication.h
index b507b167..0b81b35a 100644
--- a/src/api/burn/WixToolset.BootstrapperCore.Native/inc/BootstrapperApplication.h
+++ b/src/api/burn/WixToolset.BootstrapperCore.Native/inc/BootstrapperApplication.h
@@ -223,6 +223,7 @@ enum BOOTSTRAPPER_APPLICATION_MESSAGE
     BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANNEDCOMPATIBLEPACKAGE,
     BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANRESTORERELATEDBUNDLE,
     BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANRELATEDBUNDLETYPE,
+    BOOTSTRAPPER_APPLICATION_MESSAGE_ONAPPLYDOWNGRADE,
 };
 
 enum BOOTSTRAPPER_APPLYCOMPLETE_ACTION
@@ -354,6 +355,18 @@ struct BA_ONAPPLYCOMPLETE_RESULTS
     BOOTSTRAPPER_APPLYCOMPLETE_ACTION action;
 };
 
+struct BA_ONAPPLYDOWNGRADE_ARGS
+{
+    DWORD cbSize;
+    HRESULT hrRecommended;
+};
+
+struct BA_ONAPPLYDOWNGRADE_RESULTS
+{
+    DWORD cbSize;
+    HRESULT hrStatus;
+};
+
 struct BA_ONBEGINMSITRANSACTIONBEGIN_ARGS
 {
     DWORD cbSize;
diff --git a/src/api/burn/WixToolset.Mba.Core/BootstrapperApplication.cs b/src/api/burn/WixToolset.Mba.Core/BootstrapperApplication.cs
index fd36cf26..8a2e0e93 100644
--- a/src/api/burn/WixToolset.Mba.Core/BootstrapperApplication.cs
+++ b/src/api/burn/WixToolset.Mba.Core/BootstrapperApplication.cs
@@ -209,6 +209,9 @@ namespace WixToolset.Mba.Core
         public event EventHandler<ApplyCompleteEventArgs> ApplyComplete;
 
         /// <inheritdoc/>
+        public event EventHandler<ApplyDowngradeEventArgs> ApplyDowngrade;
+
+        /// <inheritdoc/>
         public event EventHandler<ExecuteProgressEventArgs> ExecuteProgress;
 
         /// <inheritdoc/>
@@ -1056,6 +1059,19 @@ namespace WixToolset.Mba.Core
         }
 
         /// <summary>
+        /// Called by the engine, raises the <see cref="ApplyDowngrade"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnApplyDowngrade(ApplyDowngradeEventArgs args)
+        {
+            EventHandler<ApplyDowngradeEventArgs> handler = this.ApplyDowngrade;
+            if (null != handler)
+            {
+                handler(this, args);
+            }
+        }
+
+        /// <summary>
         /// Called by the engine, raises the <see cref="ExecuteProgress"/> event.
         /// </summary>
         /// <param name="args">Additional arguments for this event.</param>
@@ -1907,6 +1923,15 @@ namespace WixToolset.Mba.Core
             return args.HResult;
         }
 
+        int IBootstrapperApplication.OnApplyDowngrade(int hrRecommendation, ref int hrStatus)
+        {
+            ApplyDowngradeEventArgs args = new ApplyDowngradeEventArgs(hrRecommendation, hrStatus);
+            this.OnApplyDowngrade(args);
+
+            hrStatus = args.Status;
+            return args.HResult;
+        }
+
         int IBootstrapperApplication.OnLaunchApprovedExeBegin(ref bool fCancel)
         {
             LaunchApprovedExeBeginEventArgs args = new LaunchApprovedExeBeginEventArgs(fCancel);
diff --git a/src/api/burn/WixToolset.Mba.Core/EventArgs.cs b/src/api/burn/WixToolset.Mba.Core/EventArgs.cs
index d8ec7998..c93c2885 100644
--- a/src/api/burn/WixToolset.Mba.Core/EventArgs.cs
+++ b/src/api/burn/WixToolset.Mba.Core/EventArgs.cs
@@ -1859,6 +1859,30 @@ namespace WixToolset.Mba.Core
     }
 
     /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.ApplyDowngrade"/>
+    /// </summary>
+    [Serializable]
+    public class ApplyDowngradeEventArgs : HResultEventArgs
+    {
+        /// <summary />
+        public ApplyDowngradeEventArgs(int hrRecommendation, int hrStatus)
+        {
+            this.Recommendation = hrRecommendation;
+            this.Status = hrStatus;
+        }
+
+        /// <summary>
+        /// Gets the recommended HRESULT.
+        /// </summary>
+        public int Recommendation { get; private set; }
+
+        /// <summary>
+        /// Gets or sets the HRESULT for Apply.
+        /// </summary>
+        public int Status { get; set; }
+    }
+
+    /// <summary>
     /// EventArgs for <see cref="IDefaultBootstrapperApplication.CacheAcquireResolving"/>.
     /// </summary>
     [Serializable]
diff --git a/src/api/burn/WixToolset.Mba.Core/IBootstrapperApplication.cs b/src/api/burn/WixToolset.Mba.Core/IBootstrapperApplication.cs
index 4ab0f8d9..d4fe8320 100644
--- a/src/api/burn/WixToolset.Mba.Core/IBootstrapperApplication.cs
+++ b/src/api/burn/WixToolset.Mba.Core/IBootstrapperApplication.cs
@@ -1160,6 +1160,16 @@ namespace WixToolset.Mba.Core
             [MarshalAs(UnmanagedType.U4)] ref RelatedBundlePlanType pRequestedType,
             [MarshalAs(UnmanagedType.Bool)] ref bool fCancel
             );
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.ApplyDowngrade"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnApplyDowngrade(
+            [MarshalAs(UnmanagedType.I4)] int hrRecommended,
+            [MarshalAs(UnmanagedType.I4)] ref int hrStatus
+            );
     }
 
     /// <summary>
diff --git a/src/api/burn/WixToolset.Mba.Core/IDefaultBootstrapperApplication.cs b/src/api/burn/WixToolset.Mba.Core/IDefaultBootstrapperApplication.cs
index ebd1580b..c9284b69 100644
--- a/src/api/burn/WixToolset.Mba.Core/IDefaultBootstrapperApplication.cs
+++ b/src/api/burn/WixToolset.Mba.Core/IDefaultBootstrapperApplication.cs
@@ -20,6 +20,11 @@ namespace WixToolset.Mba.Core
         event EventHandler<ApplyCompleteEventArgs> ApplyComplete;
 
         /// <summary>
+        /// Fired when the plan determined that nothing should happen to prevent downgrading.
+        /// </summary>
+        event EventHandler<ApplyDowngradeEventArgs> ApplyDowngrade;
+
+        /// <summary>
         /// Fired when the engine is about to begin an MSI transaction.
         /// </summary>
         event EventHandler<BeginMsiTransactionBeginEventArgs> BeginMsiTransactionBegin;
diff --git a/src/api/burn/balutil/inc/BAFunctions.h b/src/api/burn/balutil/inc/BAFunctions.h
index f772eb3f..58c26166 100644
--- a/src/api/burn/balutil/inc/BAFunctions.h
+++ b/src/api/burn/balutil/inc/BAFunctions.h
@@ -90,6 +90,7 @@ enum BA_FUNCTIONS_MESSAGE
     BA_FUNCTIONS_MESSAGE_ONPLANNEDCOMPATIBLEPACKAGE = BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANNEDCOMPATIBLEPACKAGE,
     BA_FUNCTIONS_MESSAGE_ONPLANRESTORERELATEDBUNDLE = BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANRESTORERELATEDBUNDLE,
     BA_FUNCTIONS_MESSAGE_ONPLANRELATEDBUNDLETYPE = BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANRELATEDBUNDLETYPE,
+    BA_FUNCTIONS_MESSAGE_ONAPPLYDOWNGRADE = BOOTSTRAPPER_APPLICATION_MESSAGE_ONAPPLYDOWNGRADE,
 
     BA_FUNCTIONS_MESSAGE_ONTHEMELOADED = 1024,
     BA_FUNCTIONS_MESSAGE_WNDPROC,
diff --git a/src/api/burn/balutil/inc/BalBaseBAFunctions.h b/src/api/burn/balutil/inc/BalBaseBAFunctions.h
index f558828f..fe5c99ba 100644
--- a/src/api/burn/balutil/inc/BalBaseBAFunctions.h
+++ b/src/api/burn/balutil/inc/BalBaseBAFunctions.h
@@ -869,6 +869,14 @@ public: // IBootstrapperApplication
         return S_OK;
     }
 
+    virtual STDMETHODIMP OnApplyDowngrade(
+        __in HRESULT /*hrRecommended*/,
+        __in HRESULT* /*phrStatus*/
+        )
+    {
+        return S_OK;
+    }
+
 public: // IBAFunctions
     virtual STDMETHODIMP OnPlan(
         )
diff --git a/src/api/burn/balutil/inc/BalBaseBAFunctionsProc.h b/src/api/burn/balutil/inc/BalBaseBAFunctionsProc.h
index ede00f28..100e5c30 100644
--- a/src/api/burn/balutil/inc/BalBaseBAFunctionsProc.h
+++ b/src/api/burn/balutil/inc/BalBaseBAFunctionsProc.h
@@ -161,6 +161,7 @@ static HRESULT WINAPI BalBaseBAFunctionsProc(
         case BA_FUNCTIONS_MESSAGE_ONPLANNEDCOMPATIBLEPACKAGE:
         case BA_FUNCTIONS_MESSAGE_ONPLANRESTORERELATEDBUNDLE:
         case BA_FUNCTIONS_MESSAGE_ONPLANRELATEDBUNDLETYPE:
+        case BA_FUNCTIONS_MESSAGE_ONAPPLYDOWNGRADE:
             hr = BalBaseBootstrapperApplicationProc((BOOTSTRAPPER_APPLICATION_MESSAGE)message, pvArgs, pvResults, pvContext);
             break;
         case BA_FUNCTIONS_MESSAGE_ONTHEMELOADED:
diff --git a/src/api/burn/balutil/inc/BalBaseBootstrapperApplication.h b/src/api/burn/balutil/inc/BalBaseBootstrapperApplication.h
index 49f4b7ca..fd06a83f 100644
--- a/src/api/burn/balutil/inc/BalBaseBootstrapperApplication.h
+++ b/src/api/burn/balutil/inc/BalBaseBootstrapperApplication.h
@@ -1069,6 +1069,14 @@ public: // IBootstrapperApplication
         return S_OK;
     }
 
+    virtual STDMETHODIMP OnApplyDowngrade(
+        __in HRESULT /*hrRecommended*/,
+        __in HRESULT* /*phrStatus*/
+        )
+    {
+        return S_OK;
+    }
+
 public: //CBalBaseBootstrapperApplication
     virtual STDMETHODIMP Initialize(
         __in const BOOTSTRAPPER_CREATE_ARGS* pCreateArgs
diff --git a/src/api/burn/balutil/inc/BalBaseBootstrapperApplicationProc.h b/src/api/burn/balutil/inc/BalBaseBootstrapperApplicationProc.h
index 698349f7..4e413e4e 100644
--- a/src/api/burn/balutil/inc/BalBaseBootstrapperApplicationProc.h
+++ b/src/api/burn/balutil/inc/BalBaseBootstrapperApplicationProc.h
@@ -738,6 +738,15 @@ static HRESULT BalBaseBAProcOnPlanRelatedBundleType(
     return pBA->OnPlanRelatedBundleType(pArgs->wzBundleId, pArgs->recommendedType, &pResults->requestedType, &pResults->fCancel);
 }
 
+static HRESULT BalBaseBAProcOnApplyDowngrade(
+    __in IBootstrapperApplication* pBA,
+    __in BA_ONAPPLYDOWNGRADE_ARGS* pArgs,
+    __inout BA_ONAPPLYDOWNGRADE_RESULTS* pResults
+    )
+{
+    return pBA->OnApplyDowngrade(pArgs->hrRecommended, &pResults->hrStatus);
+}
+
 /*******************************************************************
 BalBaseBootstrapperApplicationProc - requires pvContext to be of type IBootstrapperApplication.
                                      Provides a default mapping between the new message based BA interface and
@@ -1000,6 +1009,9 @@ static HRESULT WINAPI BalBaseBootstrapperApplicationProc(
         case BOOTSTRAPPER_APPLICATION_MESSAGE_ONPLANRELATEDBUNDLETYPE:
             hr = BalBaseBAProcOnPlanRelatedBundleType(pBA, reinterpret_cast<BA_ONPLANRELATEDBUNDLETYPE_ARGS*>(pvArgs), reinterpret_cast<BA_ONPLANRELATEDBUNDLETYPE_RESULTS*>(pvResults));
             break;
+        case BOOTSTRAPPER_APPLICATION_MESSAGE_ONAPPLYDOWNGRADE:
+            hr = BalBaseBAProcOnApplyDowngrade(pBA, reinterpret_cast<BA_ONAPPLYDOWNGRADE_ARGS*>(pvArgs), reinterpret_cast<BA_ONAPPLYDOWNGRADE_RESULTS*>(pvResults));
+            break;
         }
     }
 
diff --git a/src/api/burn/balutil/inc/IBootstrapperApplication.h b/src/api/burn/balutil/inc/IBootstrapperApplication.h
index 462df0cc..c9cf3126 100644
--- a/src/api/burn/balutil/inc/IBootstrapperApplication.h
+++ b/src/api/burn/balutil/inc/IBootstrapperApplication.h
@@ -707,4 +707,11 @@ DECLARE_INTERFACE_IID_(IBootstrapperApplication, IUnknown, "53C31D56-49C0-426B-A
         __inout BOOTSTRAPPER_RELATED_BUNDLE_PLAN_TYPE* pRequestedType,
         __inout BOOL* pfCancel
         ) = 0;
+
+    // OnApplyDowngrade - called when the plan determined that nothing should happen to prevent downgrading.
+    //
+    STDMETHOD(OnApplyDowngrade)(
+        __in HRESULT hrRecommended,
+        __inout HRESULT* phrStatus
+        ) = 0;
 };