Move the BootstrapperApplication out of proc

16 files changed, 269 insertions, 263 deletions

diff --git a/src/api/burn/WixToolset.Mba.Core/BaseBootstrapperApplicationFactory.cs b/src/api/burn/WixToolset.Mba.Core/BaseBootstrapperApplicationFactory.cs
index 339bfd8f..25995e27 100644
--- a/src/api/burn/WixToolset.Mba.Core/BaseBootstrapperApplicationFactory.cs
+++ b/src/api/burn/WixToolset.Mba.Core/BaseBootstrapperApplicationFactory.cs
@@ -6,58 +6,48 @@ namespace WixToolset.Mba.Core
     using System.Runtime.InteropServices;
 
     /// <summary>
-    /// Default implementation of <see cref="IBootstrapperApplicationFactory"/>.
+    /// This is no longer used.
     /// </summary>
+    [Obsolete("Bootstrapper applications now run out of proc and do not use a BootstrapperApplicationFactory. Remove your BootstrapperApplicationFactory class. See https://wixtoolset.org/docs/fiveforfour/ for more details.")]
     public abstract class BaseBootstrapperApplicationFactory : IBootstrapperApplicationFactory
     {
         /// <summary>
-        /// Default implementation of <see cref="IBootstrapperApplicationFactory.Create(IntPtr, IntPtr)"/>
+        /// This is no longer used.
         /// </summary>
-        /// <param name="pArgs">The args struct given by the engine when initially creating the BA.</param>
-        /// <param name="pResults">The results struct given by the engine when initially creating the BA</param>
+        /// <param name="pArgs">This is no longer used.</param>
+        /// <param name="pResults">This is no longer used.</param>
         public void Create(IntPtr pArgs, IntPtr pResults)
         {
-            InitializeFromCreateArgs(pArgs, out var engine, out var bootstrapperCommand);
-
-            var ba = this.Create(engine, bootstrapperCommand);
-            StoreBAInCreateResults(pResults, ba);
+            throw new NotImplementedException();
         }
 
         /// <summary>
-        /// Called by <see cref="BaseBootstrapperApplicationFactory.Create(IntPtr, IntPtr)"/> to get the <see cref="IBootstrapperApplication"/>.
+        /// This is no longer used.
         /// </summary>
-        /// <param name="engine">The bundle engine.</param>
-        /// <param name="bootstrapperCommand">Command information passed from the engine for the BA to perform.</param>
-        /// <returns>The <see cref="IBootstrapperApplication"/> for the bundle.</returns>
+        /// <param name="engine">This is no longer used.</param>
+        /// <param name="bootstrapperCommand">This is no longer used.</param>
+        /// <returns>This is no longer used.</returns>
         protected abstract IBootstrapperApplication Create(IEngine engine, IBootstrapperCommand bootstrapperCommand);
 
         /// <summary>
-        /// Initializes the native part of <see cref="WixToolset.Mba.Core"/>.
-        /// Most users should inherit from <see cref="BaseBootstrapperApplicationFactory"/> instead of calling this method.
+        /// This is no longer used.
         /// </summary>
-        /// <param name="pArgs">The args struct given by the engine when initially creating the BA.</param>
-        /// <param name="engine">The bundle engine interface.</param>
-        /// <param name="bootstrapperCommand">The context of the current run of the bundle.</param>
+        /// <param name="pArgs">This is no longer used.</param>
+        /// <param name="engine">This is no longer used.</param>
+        /// <param name="bootstrapperCommand">This is no longer used.</param>
         public static void InitializeFromCreateArgs(IntPtr pArgs, out IEngine engine, out IBootstrapperCommand bootstrapperCommand)
         {
-            Command pCommand = new Command
-            {
-                cbSize = Marshal.SizeOf(typeof(Command))
-            };
-            var pEngine = MbaNative.InitializeFromCreateArgs(pArgs, ref pCommand);
-            engine = new Engine(pEngine);
-            bootstrapperCommand = pCommand.GetBootstrapperCommand();
+            throw new NotImplementedException();
         }
 
         /// <summary>
-        /// Registers the BA with the engine using the default mapping between the message based interface and the COM interface.
-        /// Most users should inherit from <see cref="BaseBootstrapperApplicationFactory"/> instead of calling this method.
+        /// This is no longer used.
         /// </summary>
-        /// <param name="pResults">The results struct given by the engine when initially creating the BA</param>
-        /// <param name="ba">The <see cref="IBootstrapperApplication"/>.</param>
+        /// <param name="pResults">This is no longer used.</param>
+        /// <param name="ba">This is no longer used.</param>
         public static void StoreBAInCreateResults(IntPtr pResults, IBootstrapperApplication ba)
         {
-            MbaNative.StoreBAInCreateResults(pResults, ba);
+            throw new NotImplementedException();
         }
     }
 }
diff --git a/src/api/burn/WixToolset.Mba.Core/BootstrapperApplication.cs b/src/api/burn/WixToolset.Mba.Core/BootstrapperApplication.cs
index a0ec6ab9..98b34217 100644
--- a/src/api/burn/WixToolset.Mba.Core/BootstrapperApplication.cs
+++ b/src/api/burn/WixToolset.Mba.Core/BootstrapperApplication.cs
@@ -13,23 +13,15 @@ namespace WixToolset.Mba.Core
     public abstract class BootstrapperApplication : MarshalByRefObject, IDefaultBootstrapperApplication
     {
         /// <summary>
-        /// Specifies whether this bootstrapper should run asynchronously. The default is true.
-        /// </summary>
-        protected readonly bool asyncExecution;
-
-        /// <summary>
         /// Gets the <see cref="IEngine"/> for interaction with the engine.
         /// </summary>
-        protected readonly IEngine engine;
+        protected IEngine engine;
 
-        /// <summary>
-        /// Creates a new instance of the <see cref="BootstrapperApplication"/> class.
-        /// </summary>
-        protected BootstrapperApplication(IEngine engine)
-        {
-            this.engine = engine;
-            this.asyncExecution = true;
-        }
+        /// <inheritdoc/>
+        public event EventHandler<CreateEventArgs> Create;
+
+        /// <inheritdoc/>
+        public event EventHandler<DestroyEventArgs> Destroy;
 
         /// <inheritdoc/>
         public event EventHandler<StartupEventArgs> Startup;
@@ -266,12 +258,6 @@ namespace WixToolset.Mba.Core
         public event EventHandler<CachePayloadExtractCompleteEventArgs> CachePayloadExtractComplete;
 
         /// <inheritdoc/>
-        public event EventHandler<SetUpdateBeginEventArgs> SetUpdateBegin;
-
-        /// <inheritdoc/>
-        public event EventHandler<SetUpdateCompleteEventArgs> SetUpdateComplete;
-
-        /// <inheritdoc/>
         public event EventHandler<PlanRestoreRelatedBundleEventArgs> PlanRestoreRelatedBundle;
 
         /// <inheritdoc/>
@@ -284,35 +270,73 @@ namespace WixToolset.Mba.Core
         public event EventHandler<CachePackageNonVitalValidationFailureEventArgs> CachePackageNonVitalValidationFailure;
 
         /// <summary>
+        /// The default constructor.
+        /// </summary>
+        /// <remarks>
+        /// The engine object will be valid after handling the OnCreate() event.
+        /// </remarks>
+        protected BootstrapperApplication()
+        {
+        }
+
+        /// <summary>
+        /// This constructor is no longer used.
+        /// </summary>
+        [Obsolete("This constructor is no longer used. Use the default constructor. The engine object will be valid after handling the OnCreate() event.")]
+        protected BootstrapperApplication(IEngine engine)
+        {
+            throw new NotImplementedException("This constructor is no longer used. Use the default constructor. The engine object will be valid after handling the OnCreate() event.");
+        }
+
+        /// <summary>
         /// Entry point that is called when the bootstrapper application is ready to run.
         /// </summary>
         protected abstract void Run();
 
         /// <summary>
-        /// Called by the engine, raises the <see cref="Startup"/> event.
+        /// Called by the engine, raises the <see cref="Create"/> event.
         /// </summary>
         /// <param name="args">Additional arguments for this event.</param>
-        protected virtual void OnStartup(StartupEventArgs args)
+        protected virtual void OnCreate(CreateEventArgs args)
         {
-            EventHandler<StartupEventArgs> handler = this.Startup;
+            this.engine = args.Engine;
+
+            EventHandler<CreateEventArgs> handler = this.Create;
             if (null != handler)
             {
                 handler(this, args);
             }
+        }
 
-            if (this.asyncExecution)
+        /// <summary>
+        /// Called by the engine, raises the <see cref="Destroy"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnDestroy(DestroyEventArgs args)
+        {
+            EventHandler<DestroyEventArgs> handler = this.Destroy;
+            if (null != handler)
             {
-                this.engine.Log(LogLevel.Verbose, "Creating BA thread to run asynchronously.");
-                Thread uiThread = new Thread(this.Run);
-                uiThread.Name = "UIThread";
-                uiThread.SetApartmentState(ApartmentState.STA);
-                uiThread.Start();
+                handler(this, args);
             }
-            else
+        }
+
+        /// <summary>
+        /// Called by the engine, raises the <see cref="Startup"/> event.
+        /// </summary>
+        /// <param name="args">Additional arguments for this event.</param>
+        protected virtual void OnStartup(StartupEventArgs args)
+        {
+            EventHandler<StartupEventArgs> handler = this.Startup;
+            if (null != handler)
             {
-                this.engine.Log(LogLevel.Verbose, "Creating BA thread to run synchronously.");
-                this.Run();
+                handler(this, args);
             }
+
+            Thread uiThread = new Thread(this.Run);
+            uiThread.Name = "UIThread";
+            uiThread.SetApartmentState(ApartmentState.STA);
+            uiThread.Start();
         }
 
         /// <summary>
@@ -1315,31 +1339,6 @@ namespace WixToolset.Mba.Core
             }
         }
 
-        /// <summary>
-        /// Called by the engine, raises the <see cref="SetUpdateBegin"/> event.
-        /// </summary>
-        /// <param name="args">Additional arguments for this event.</param>
-        protected virtual void OnSetUpdateBegin(SetUpdateBeginEventArgs args)
-        {
-            EventHandler<SetUpdateBeginEventArgs> handler = this.SetUpdateBegin;
-            if (null != handler)
-            {
-                handler(this, args);
-            }
-        }
-
-        /// <summary>
-        /// Called by the engine, raises the <see cref="SetUpdateComplete"/> event.
-        /// </summary>
-        /// <param name="args">Additional arguments for this event.</param>
-        protected virtual void OnSetUpdateComplete(SetUpdateCompleteEventArgs args)
-        {
-            EventHandler<SetUpdateCompleteEventArgs> handler = this.SetUpdateComplete;
-            if (null != handler)
-            {
-                handler(this, args);
-            }
-        }
 
         /// <summary>
         /// Called by the engine, raises the <see cref="PlanRestoreRelatedBundle"/> event.
@@ -1395,7 +1394,7 @@ namespace WixToolset.Mba.Core
 
         #region IBootstrapperApplication Members
 
-        int IBootstrapperApplication.BAProc(int message, IntPtr pvArgs, IntPtr pvResults, IntPtr pvContext)
+        int IBootstrapperApplication.BAProc(int message, IntPtr pvArgs, IntPtr pvResults)
         {
             switch (message)
             {
@@ -1404,8 +1403,24 @@ namespace WixToolset.Mba.Core
             }
         }
 
-        void IBootstrapperApplication.BAProcFallback(int message, IntPtr pvArgs, IntPtr pvResults, ref int phr, IntPtr pvContext)
+        void IBootstrapperApplication.BAProcFallback(int message, IntPtr pvArgs, IntPtr pvResults, ref int phr)
+        {
+        }
+
+        int IBootstrapperApplication.OnCreate(IBootstrapperEngine engine, ref Command command)
         {
+            CreateEventArgs args = new CreateEventArgs(new Engine(engine), command.GetBootstrapperCommand());
+            this.OnCreate(args);
+
+            return args.HResult;
+        }
+
+        int IBootstrapperApplication.OnDestroy(bool reload)
+        {
+            DestroyEventArgs args = new DestroyEventArgs(reload);
+            this.OnDestroy(args);
+
+            return args.HResult;
         }
 
         int IBootstrapperApplication.OnStartup()
@@ -2107,22 +2122,6 @@ namespace WixToolset.Mba.Core
             return args.HResult;
         }
 
-        int IBootstrapperApplication.OnSetUpdateBegin()
-        {
-            SetUpdateBeginEventArgs args = new SetUpdateBeginEventArgs();
-            this.OnSetUpdateBegin(args);
-
-            return args.HResult;
-        }
-
-        int IBootstrapperApplication.OnSetUpdateComplete(int hrStatus, string wzPreviousPackageId, string wzNewPackageId)
-        {
-            SetUpdateCompleteEventArgs args = new SetUpdateCompleteEventArgs(hrStatus, wzPreviousPackageId, wzNewPackageId);
-            this.OnSetUpdateComplete(args);
-
-            return args.HResult;
-        }
-
         int IBootstrapperApplication.OnPlanRestoreRelatedBundle(string wzBundleId, RequestState recommendedState, ref RequestState pRequestedState, ref bool fCancel)
         {
             PlanRestoreRelatedBundleEventArgs args = new PlanRestoreRelatedBundleEventArgs(wzBundleId, recommendedState, pRequestedState, fCancel);
diff --git a/src/api/burn/WixToolset.Mba.Core/BootstrapperApplicationFactoryAttribute.cs b/src/api/burn/WixToolset.Mba.Core/BootstrapperApplicationFactoryAttribute.cs
index 95252cf3..6b465408 100644
--- a/src/api/burn/WixToolset.Mba.Core/BootstrapperApplicationFactoryAttribute.cs
+++ b/src/api/burn/WixToolset.Mba.Core/BootstrapperApplicationFactoryAttribute.cs
@@ -5,31 +5,27 @@ namespace WixToolset.Mba.Core
     using System;
 
     /// <summary>
-    /// Identifies the bootstrapper application factory class.
+    /// This is no longer used.
     /// </summary>
-    /// <remarks>
-    /// This required assembly attribute identifies the bootstrapper application factory class.
-    /// </remarks>
+    [Obsolete("Bootstrapper applications now run out of proc and do not use a BootstrapperApplicationFactory. Remove your BootstrapperApplicationFactory class. See https://wixtoolset.org/docs/fiveforfour/ for more details.")]
     [AttributeUsage(AttributeTargets.Assembly, AllowMultiple = false)]
     public sealed class BootstrapperApplicationFactoryAttribute : Attribute
     {
-        private Type bootstrapperApplicationFactoryType;
-
         /// <summary>
-        /// Creates a new instance of the <see cref="BootstrapperApplicationFactoryAttribute"/> class.
+        /// This is no longer used.
         /// </summary>
-        /// <param name="bootstrapperApplicationFactoryType">The <see cref="Type"/> of the BA factory.</param>
+        /// <param name="bootstrapperApplicationFactoryType">This is no longer used</param>
         public BootstrapperApplicationFactoryAttribute(Type bootstrapperApplicationFactoryType)
         {
-            this.bootstrapperApplicationFactoryType = bootstrapperApplicationFactoryType;
+            throw new NotImplementedException();
         }
 
         /// <summary>
-        /// Gets the type of the bootstrapper application factory class to create.
+        /// This is no longer used.
         /// </summary>
         public Type BootstrapperApplicationFactoryType
         {
-            get { return this.bootstrapperApplicationFactoryType; }
+            get { throw new NotImplementedException(); }
         }
     }
 }
diff --git a/src/api/burn/WixToolset.Mba.Core/BootstrapperCommand.cs b/src/api/burn/WixToolset.Mba.Core/BootstrapperCommand.cs
index ed1dc191..b96a8f95 100644
--- a/src/api/burn/WixToolset.Mba.Core/BootstrapperCommand.cs
+++ b/src/api/burn/WixToolset.Mba.Core/BootstrapperCommand.cs
@@ -3,11 +3,55 @@
 namespace WixToolset.Mba.Core
 {
     using System;
+    using System.CodeDom.Compiler;
     using System.Collections.Generic;
     using System.ComponentModel;
     using System.Runtime.InteropServices;
 
     /// <summary>
+    /// Command-line provided to the bootstrapper application.
+    /// </summary>
+    [Serializable]
+    [StructLayout(LayoutKind.Sequential)]
+    [GeneratedCodeAttribute("WixToolset.Bootstrapper.InteropCodeGenerator", "1.0.0.0")]
+    public struct Command
+    {
+        // Strings must be declared as pointers so that Marshaling doesn't free them.
+        [MarshalAs(UnmanagedType.I4)] internal int cbSize;
+        [MarshalAs(UnmanagedType.U4)] private readonly LaunchAction action;
+        [MarshalAs(UnmanagedType.U4)] private readonly Display display;
+        private readonly IntPtr wzCommandLine;
+        [MarshalAs(UnmanagedType.I4)] private readonly int nCmdShow;
+        [MarshalAs(UnmanagedType.U4)] private readonly ResumeType resume;
+        private readonly IntPtr hwndSplashScreen;
+        [MarshalAs(UnmanagedType.I4)] private readonly RelationType relation;
+        [MarshalAs(UnmanagedType.Bool)] private readonly bool passthrough;
+        private readonly IntPtr wzLayoutDirectory;
+        private readonly IntPtr wzBootstrapperWorkingFolder;
+        private readonly IntPtr wzBootstrapperApplicationDataPath;
+
+        /// <summary>
+        /// Gets the IBootstrapperCommand for this Command.
+        /// </summary>
+        /// <returns>IBootstrapperCommand</returns>
+        public IBootstrapperCommand GetBootstrapperCommand()
+        {
+            return new BootstrapperCommand(
+                this.action,
+                this.display,
+                Marshal.PtrToStringUni(this.wzCommandLine),
+                this.nCmdShow,
+                this.resume,
+                this.hwndSplashScreen,
+                this.relation,
+                this.passthrough,
+                Marshal.PtrToStringUni(this.wzLayoutDirectory),
+                Marshal.PtrToStringUni(this.wzBootstrapperWorkingFolder),
+                Marshal.PtrToStringUni(this.wzBootstrapperApplicationDataPath));
+        }
+    }
+
+    /// <summary>
     /// Default implementation of <see cref="IBootstrapperCommand"/>.
     /// </summary>
     public sealed class BootstrapperCommand : IBootstrapperCommand
diff --git a/src/api/burn/WixToolset.Mba.Core/BundleInfo.cs b/src/api/burn/WixToolset.Mba.Core/BundleInfo.cs
index ee751ebf..0039f375 100644
--- a/src/api/burn/WixToolset.Mba.Core/BundleInfo.cs
+++ b/src/api/burn/WixToolset.Mba.Core/BundleInfo.cs
@@ -34,17 +34,17 @@ namespace WixToolset.Mba.Core
         }
 
         /// <inheritdoc/>
-        public IPackageInfo AddRelatedBundleAsPackage(DetectRelatedBundleEventArgs e)
+        public IPackageInfo AddRelatedBundleAsPackage(string productCode, RelationType relationType, bool perMachine, string version)
         {
-            var package = PackageInfo.GetRelatedBundleAsPackage(e.ProductCode, e.RelationType, e.PerMachine, e.Version);
+            var package = PackageInfo.GetRelatedBundleAsPackage(productCode, relationType, perMachine, version);
             this.Packages.Add(package.Id, package);
             return package;
         }
 
         /// <inheritdoc/>
-        public IPackageInfo AddUpdateBundleAsPackage(SetUpdateCompleteEventArgs e)
+        public IPackageInfo AddUpdateBundleAsPackage(string packageId)
         {
-            var package = PackageInfo.GetUpdateBundleAsPackage(e.NewPackageId);
+            var package = PackageInfo.GetUpdateBundleAsPackage(packageId);
             this.Packages.Add(package.Id, package);
             return package;
         }
diff --git a/src/api/burn/WixToolset.Mba.Core/Engine.cs b/src/api/burn/WixToolset.Mba.Core/Engine.cs
index 1120fb1c..df412e8c 100644
--- a/src/api/burn/WixToolset.Mba.Core/Engine.cs
+++ b/src/api/burn/WixToolset.Mba.Core/Engine.cs
@@ -253,9 +253,9 @@ namespace WixToolset.Mba.Core
         }
 
         /// <inheritdoc/>
-        public void SetUpdate(string localSource, string downloadSource, long size, UpdateHashType hashType, string hash)
+        public void SetUpdate(string localSource, string downloadSource, long size, UpdateHashType hashType, string hash, string updatePackageId)
         {
-            this.engine.SetUpdate(localSource, downloadSource, size, hashType, hash);
+            this.engine.SetUpdate(localSource, downloadSource, size, hashType, hash, updatePackageId);
         }
 
         /// <inheritdoc/>
diff --git a/src/api/burn/WixToolset.Mba.Core/EventArgs.cs b/src/api/burn/WixToolset.Mba.Core/EventArgs.cs
index 4b7f2245..6506c840 100644
--- a/src/api/burn/WixToolset.Mba.Core/EventArgs.cs
+++ b/src/api/burn/WixToolset.Mba.Core/EventArgs.cs
@@ -198,6 +198,54 @@ namespace WixToolset.Mba.Core
     }
 
     /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.Create"/>.
+    /// </summary>
+    [Serializable]
+    public class CreateEventArgs : HResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public CreateEventArgs(IEngine engine, IBootstrapperCommand command)
+        {
+            this.Engine = engine;
+            this.Command = command;
+        }
+
+        /// <summary>
+        /// Engine running the application.
+        /// </summary>
+        public IEngine Engine { get; }
+
+        /// <summary>
+        /// Command line arguments.
+        /// </summary>
+        public IBootstrapperCommand Command { get; }
+    }
+
+    /// <summary>
+    /// Event arguments for <see cref="IDefaultBootstrapperApplication.Destroy"/>.
+    /// </summary>
+    [Serializable]
+    public class DestroyEventArgs : HResultEventArgs
+    {
+        /// <summary>
+        /// This class is for events raised by the engine.
+        /// It is not intended to be instantiated by user code.
+        /// </summary>
+        public DestroyEventArgs(bool reload)
+        {
+            this.Reload = reload;
+        }
+
+        /// <summary>
+        /// Bootstrapper application is being reloaded.
+        /// </summary>
+        public bool Reload { get; }
+    }
+
+    /// <summary>
     /// Event arguments for <see cref="IDefaultBootstrapperApplication.Startup"/>.
     /// </summary>
     [Serializable]
@@ -2567,49 +2615,6 @@ namespace WixToolset.Mba.Core
     }
 
     /// <summary>
-    /// EventArgs for <see cref="IDefaultBootstrapperApplication.SetUpdateBegin"/>.
-    /// </summary>
-    [Serializable]
-    public class SetUpdateBeginEventArgs : HResultEventArgs
-    {
-        /// <summary>
-        /// This class is for events raised by the engine.
-        /// It is not intended to be instantiated by user code.
-        /// </summary>
-        public SetUpdateBeginEventArgs()
-        {
-        }
-    }
-
-    /// <summary>
-    /// Event arguments for <see cref="IDefaultBootstrapperApplication.SetUpdateComplete"/>
-    /// </summary>
-    [Serializable]
-    public class SetUpdateCompleteEventArgs : StatusEventArgs
-    {
-        /// <summary>
-        /// This class is for events raised by the engine.
-        /// It is not intended to be instantiated by user code.
-        /// </summary>
-        public SetUpdateCompleteEventArgs(int hrStatus, string previousPackageId, string newPackageId)
-            : base(hrStatus)
-        {
-            this.PreviousPackageId = previousPackageId;
-            this.NewPackageId = newPackageId;
-        }
-
-        /// <summary>
-        /// Gets the identifier of the update package that was removed.
-        /// </summary>
-        public string PreviousPackageId { get; private set; }
-
-        /// <summary>
-        /// Gets the identifier of the update package that was added.
-        /// </summary>
-        public string NewPackageId { get; private set; }
-    }
-
-    /// <summary>
     /// Event arguments for <see cref="IDefaultBootstrapperApplication.PlanRestoreRelatedBundle"/>
     /// </summary>
     [Serializable]
diff --git a/src/api/burn/WixToolset.Mba.Core/IBootstrapperApplication.cs b/src/api/burn/WixToolset.Mba.Core/IBootstrapperApplication.cs
index 36c7fd33..8a255c44 100644
--- a/src/api/burn/WixToolset.Mba.Core/IBootstrapperApplication.cs
+++ b/src/api/burn/WixToolset.Mba.Core/IBootstrapperApplication.cs
@@ -21,8 +21,7 @@ namespace WixToolset.Mba.Core
         int BAProc(
             int message,
             IntPtr pvArgs,
-            IntPtr pvResults,
-            IntPtr pvContext
+            IntPtr pvResults
             );
 
         /// <summary>
@@ -32,11 +31,24 @@ namespace WixToolset.Mba.Core
             int message,
             IntPtr pvArgs,
             IntPtr pvResults,
-            ref int phr,
-            IntPtr pvContext
+            ref int phr
             );
 
         /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.Create"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnCreate(IBootstrapperEngine engine, ref Command command);
+
+        /// <summary>
+        /// See <see cref="IDefaultBootstrapperApplication.Destroy"/>.
+        /// </summary>
+        [PreserveSig]
+        [return: MarshalAs(UnmanagedType.I4)]
+        int OnDestroy(bool reload);
+
+        /// <summary>
         /// See <see cref="IDefaultBootstrapperApplication.Startup"/>.
         /// </summary>
         [PreserveSig]
@@ -940,24 +952,6 @@ namespace WixToolset.Mba.Core
             );
 
         /// <summary>
-        /// See <see cref="IDefaultBootstrapperApplication.SetUpdateBegin"/>.
-        /// </summary>
-        [PreserveSig]
-        [return: MarshalAs(UnmanagedType.I4)]
-        int OnSetUpdateBegin();
-
-        /// <summary>
-        /// See <see cref="IDefaultBootstrapperApplication.SetUpdateComplete"/>.
-        /// </summary>
-        [PreserveSig]
-        [return: MarshalAs(UnmanagedType.I4)]
-        int OnSetUpdateComplete(
-            int hrStatus,
-            [MarshalAs(UnmanagedType.LPWStr)] string wzPreviousPackageId,
-            [MarshalAs(UnmanagedType.LPWStr)] string wzNewPackageId
-            );
-
-        /// <summary>
         /// See <see cref="IDefaultBootstrapperApplication.PlanRestoreRelatedBundle"/>.
         /// </summary>
         [PreserveSig]
diff --git a/src/api/burn/WixToolset.Mba.Core/IBootstrapperApplicationFactory.cs b/src/api/burn/WixToolset.Mba.Core/IBootstrapperApplicationFactory.cs
index 2e84de67..393c7e31 100644
--- a/src/api/burn/WixToolset.Mba.Core/IBootstrapperApplicationFactory.cs
+++ b/src/api/burn/WixToolset.Mba.Core/IBootstrapperApplicationFactory.cs
@@ -7,58 +7,16 @@ namespace WixToolset.Mba.Core
     using System.Runtime.InteropServices;
 
     /// <summary>
-    /// Interface used by the native host to dynamically load the BA.
+    /// This is no longer used.
     /// </summary>
-    [ComVisible(true)]
-    [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
-    [Guid("2965A12F-AC7B-43A0-85DF-E4B2168478A4")]
-    [GeneratedCodeAttribute("WixToolset.Bootstrapper.InteropCodeGenerator", "1.0.0.0")]
+    [Obsolete("Bootstrapper applications now run out of proc and do not use a BootstrapperApplicationFactory. Remove your BootstrapperApplicationFactory class. See https://wixtoolset.org/docs/fiveforfour/ for more details.")]
     public interface IBootstrapperApplicationFactory
     {
         /// <summary>
-        /// Low level method called by the native host.
+        /// This is no longer used.
         /// </summary>
-        /// <param name="pArgs"></param>
-        /// <param name="pResults"></param>
-        void Create(
-            IntPtr pArgs,
-            IntPtr pResults
-            );
-    }
-
-    [Serializable]
-    [StructLayout(LayoutKind.Sequential)]
-    [GeneratedCodeAttribute("WixToolset.Bootstrapper.InteropCodeGenerator", "1.0.0.0")]
-    internal struct Command
-    {
-        // Strings must be declared as pointers so that Marshaling doesn't free them.
-        [MarshalAs(UnmanagedType.I4)] internal int cbSize;
-        [MarshalAs(UnmanagedType.U4)] private readonly LaunchAction action;
-        [MarshalAs(UnmanagedType.U4)] private readonly Display display;
-        private readonly IntPtr wzCommandLine;
-        [MarshalAs(UnmanagedType.I4)] private readonly int nCmdShow;
-        [MarshalAs(UnmanagedType.U4)] private readonly ResumeType resume;
-        private readonly IntPtr hwndSplashScreen;
-        [MarshalAs(UnmanagedType.I4)] private readonly RelationType relation;
-        [MarshalAs(UnmanagedType.Bool)] private readonly bool passthrough;
-        private readonly IntPtr wzLayoutDirectory;
-        private readonly IntPtr wzBootstrapperWorkingFolder;
-        private readonly IntPtr wzBootstrapperApplicationDataPath;
-
-        public IBootstrapperCommand GetBootstrapperCommand()
-        {
-            return new BootstrapperCommand(
-                this.action,
-                this.display,
-                Marshal.PtrToStringUni(this.wzCommandLine),
-                this.nCmdShow,
-                this.resume,
-                this.hwndSplashScreen,
-                this.relation,
-                this.passthrough,
-                Marshal.PtrToStringUni(this.wzLayoutDirectory),
-                Marshal.PtrToStringUni(this.wzBootstrapperWorkingFolder),
-                Marshal.PtrToStringUni(this.wzBootstrapperApplicationDataPath));
-        }
+        /// <param name="pArgs">This is no longer used.</param>
+        /// <param name="pResults">This is no longer used.</param>
+        void Create(IntPtr pArgs, IntPtr pResults);
     }
 }
diff --git a/src/api/burn/WixToolset.Mba.Core/IBootstrapperEngine.cs b/src/api/burn/WixToolset.Mba.Core/IBootstrapperEngine.cs
index 3f90639f..a175bead 100644
--- a/src/api/burn/WixToolset.Mba.Core/IBootstrapperEngine.cs
+++ b/src/api/burn/WixToolset.Mba.Core/IBootstrapperEngine.cs
@@ -108,14 +108,15 @@ namespace WixToolset.Mba.Core
             );
 
         /// <summary>
-        /// See <see cref="IEngine.SetUpdate(string, string, long, UpdateHashType, string)"/>.
+        /// See <see cref="IEngine.SetUpdate(string, string, long, UpdateHashType, string, string)"/>.
         /// </summary>
         void SetUpdate(
             [MarshalAs(UnmanagedType.LPWStr)] string wzLocalSource,
             [MarshalAs(UnmanagedType.LPWStr)] string wzDownloadSource,
             [MarshalAs(UnmanagedType.U8)] long qwValue,
             [MarshalAs(UnmanagedType.U4)] UpdateHashType hashType,
-            [MarshalAs(UnmanagedType.LPWStr)] string wzHash
+            [MarshalAs(UnmanagedType.LPWStr)] string wzHash,
+            [MarshalAs(UnmanagedType.LPWStr)] string wzUpdatePackageId
             );
 
         /// <summary>
@@ -330,12 +331,12 @@ namespace WixToolset.Mba.Core
         Repair,
 
         /// <summary>
-        /// Launch the update registered with <see cref="IEngine.SetUpdate(string, string, long, UpdateHashType, string)"/> and then exit without waiting for it to complete.
+        /// Launch the update registered with <see cref="IEngine.SetUpdate(string, string, long, UpdateHashType, string, string)"/> and then exit without waiting for it to complete.
         /// </summary>
         UpdateReplace,
 
         /// <summary>
-        /// Launch the update registered with <see cref="IEngine.SetUpdate(string, string, long, UpdateHashType, string)"/> as an embedded bundle.
+        /// Launch the update registered with <see cref="IEngine.SetUpdate(string, string, long, UpdateHashType, string, string)"/> as an embedded bundle.
         /// </summary>
         UpdateReplaceEmbedded,
     }
diff --git a/src/api/burn/WixToolset.Mba.Core/IBundleInfo.cs b/src/api/burn/WixToolset.Mba.Core/IBundleInfo.cs
index 951f511a..3c52fc02 100644
--- a/src/api/burn/WixToolset.Mba.Core/IBundleInfo.cs
+++ b/src/api/burn/WixToolset.Mba.Core/IBundleInfo.cs
@@ -37,15 +37,18 @@ namespace WixToolset.Mba.Core
         /// <summary>
         /// Adds a related bundle as a package.
         /// </summary>
-        /// <param name="e"></param>
+        /// <param name="productCode"></param>
+        /// <param name="relationType"></param>
+        /// <param name="perMachine"></param>
+        /// <param name="version"></param>
         /// <returns>The created <see cref="IPackageInfo"/>.</returns>
-        IPackageInfo AddRelatedBundleAsPackage(DetectRelatedBundleEventArgs e);
+        IPackageInfo AddRelatedBundleAsPackage(string productCode, RelationType relationType, bool perMachine, string version);
 
         /// <summary>
         /// Adds an update bundle as a package.
         /// </summary>
-        /// <param name="e"></param>
+        /// <param name="packageId">Package id added as update bundle.</param>
         /// <returns>The created <see cref="IPackageInfo"/>.</returns>
-        IPackageInfo AddUpdateBundleAsPackage(SetUpdateCompleteEventArgs e);
+        IPackageInfo AddUpdateBundleAsPackage(string packageId);
     }
 }
diff --git a/src/api/burn/WixToolset.Mba.Core/IDefaultBootstrapperApplication.cs b/src/api/burn/WixToolset.Mba.Core/IDefaultBootstrapperApplication.cs
index 2fa88bdb..51ea4e4d 100644
--- a/src/api/burn/WixToolset.Mba.Core/IDefaultBootstrapperApplication.cs
+++ b/src/api/burn/WixToolset.Mba.Core/IDefaultBootstrapperApplication.cs
@@ -139,6 +139,16 @@ namespace WixToolset.Mba.Core
         event EventHandler<CommitMsiTransactionCompleteEventArgs> CommitMsiTransactionComplete;
 
         /// <summary>
+        /// Fired when the application is being created.
+        /// </summary>
+        event EventHandler<CreateEventArgs> Create;
+
+        /// <summary>
+        /// Fired when the application is being destroyed.
+        /// </summary>
+        event EventHandler<DestroyEventArgs> Destroy;
+
+        /// <summary>
         /// Fired when the overall detection phase has begun.
         /// </summary>
         event EventHandler<DetectBeginEventArgs> DetectBegin;
@@ -394,16 +404,6 @@ namespace WixToolset.Mba.Core
         event EventHandler<RollbackMsiTransactionCompleteEventArgs> RollbackMsiTransactionComplete;
 
         /// <summary>
-        /// Fired when the engine has begun to setup the update package.
-        /// </summary>
-        event EventHandler<SetUpdateBeginEventArgs> SetUpdateBegin;
-
-        /// <summary>
-        /// Fired when the engine has completed setting up the update package.
-        /// </summary>
-        event EventHandler<SetUpdateCompleteEventArgs> SetUpdateComplete;
-
-        /// <summary>
         /// Fired when the engine is shutting down the bootstrapper application.
         /// </summary>
         event EventHandler<ShutdownEventArgs> Shutdown;
diff --git a/src/api/burn/WixToolset.Mba.Core/IEngine.cs b/src/api/burn/WixToolset.Mba.Core/IEngine.cs
index 7ffa80d7..dde97a70 100644
--- a/src/api/burn/WixToolset.Mba.Core/IEngine.cs
+++ b/src/api/burn/WixToolset.Mba.Core/IEngine.cs
@@ -149,7 +149,8 @@ namespace WixToolset.Mba.Core
         /// <param name="size">Size of the expected update.</param>
         /// <param name="hashType">Type of the hash expected on the update.</param>
         /// <param name="hash">Optional hash expected for the update.</param>
-        void SetUpdate(string localSource, string downloadSource, long size, UpdateHashType hashType, string hash);
+        /// <param name="updatePackageId">Optional package id for the update.</param>
+        void SetUpdate(string localSource, string downloadSource, long size, UpdateHashType hashType, string hash, string updatePackageId);
 
         /// <summary>
         /// Sets the URL to the update feed.
diff --git a/src/api/burn/WixToolset.Mba.Core/ManagedBootstrapperApplication.cs b/src/api/burn/WixToolset.Mba.Core/ManagedBootstrapperApplication.cs
new file mode 100644
index 00000000..74bfbd73
--- /dev/null
+++ b/src/api/burn/WixToolset.Mba.Core/ManagedBootstrapperApplication.cs
@@ -0,0 +1,19 @@
+// 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.Mba.Core
+{
+    /// <summary>
+    /// Managed bootstrapper application entry point.
+    /// </summary>
+    public static class ManagedBootstrapperApplication
+    {
+        /// <summary>
+        /// Run the managed bootstrapper application.
+        /// </summary>
+        /// <param name="application">Bootstrapper applciation to run.</param>
+        public static void Run(IBootstrapperApplication application)
+        {
+            MbaNative.BootstrapperApplicationRun(application);
+        }
+    }
+}
diff --git a/src/api/burn/WixToolset.Mba.Core/MbaNative.cs b/src/api/burn/WixToolset.Mba.Core/MbaNative.cs
index a68a3907..e8e9d576 100644
--- a/src/api/burn/WixToolset.Mba.Core/MbaNative.cs
+++ b/src/api/burn/WixToolset.Mba.Core/MbaNative.cs
@@ -8,14 +8,10 @@ namespace WixToolset.Mba.Core
     internal static class MbaNative
     {
         [DllImport("mbanative.dll", ExactSpelling = true, PreserveSig = false)]
-        internal static extern IBootstrapperEngine InitializeFromCreateArgs(
-            IntPtr pArgs,
-            ref Command pCommand
-            );
+        internal static extern void BootstrapperApplicationDebuggerCheck();
 
-        [DllImport("mbanative.dll", ExactSpelling = true)]
-        internal static extern void StoreBAInCreateResults(
-            IntPtr pResults,
+        [DllImport("mbanative.dll", ExactSpelling = true, PreserveSig = false)]
+        internal static extern void BootstrapperApplicationRun(
             [MarshalAs(UnmanagedType.Interface)] IBootstrapperApplication pBA
             );
     }
diff --git a/src/api/burn/WixToolset.Mba.Core/PackageInfo.cs b/src/api/burn/WixToolset.Mba.Core/PackageInfo.cs
index c6373647..b91c52c9 100644
--- a/src/api/burn/WixToolset.Mba.Core/PackageInfo.cs
+++ b/src/api/burn/WixToolset.Mba.Core/PackageInfo.cs
@@ -365,19 +365,19 @@ namespace WixToolset.Mba.Core
                 package.DisplayInternalUICondition = BootstrapperApplicationData.GetAttribute(node, "DisplayInternalUICondition");
             }
 
-            nodes = root.Select("/p:BootstrapperApplicationData/p:WixMbaPrereqInformation", namespaceManager);
+            nodes = root.Select("/p:BootstrapperApplicationData/p:WixPrereqInformation", namespaceManager);
 
             foreach (XPathNavigator node in nodes)
             {
                 string id = BootstrapperApplicationData.GetAttribute(node, "PackageId");
                 if (id == null)
                 {
-                    throw new Exception("Failed to get package identifier for WixMbaPrereqInformation.");
+                    throw new Exception("Failed to get package identifier for WixPrereqInformation.");
                 }
 
                 if (!packagesById.TryGetValue(id, out var ipackage))
                 {
-                    throw new Exception(String.Format("Failed to find package specified in WixMbaPrereqInformation: {0}", id));
+                    throw new Exception(String.Format("Failed to find package specified in WixPrereqInformation: {0}", id));
                 }
 
                 var package = (PackageInfo)ipackage;