Add support for BundleExtensions.

15 files changed, 701 insertions, 14 deletions

diff --git a/src/engine/EngineForApplication.cpp b/src/engine/EngineForApplication.cpp
index eda5fc64..c3600c7b 100644
--- a/src/engine/EngineForApplication.cpp
+++ b/src/engine/EngineForApplication.cpp
@@ -593,7 +593,7 @@ static HRESULT BAEngineSetVariableString(
     if (wzVariable && *wzVariable)
     {
         hr = VariableSetString(&pContext->pEngineState->variables, wzVariable, wzValue, FALSE);
-        ExitOnFailure(hr, "Failed to set numeric variable.");
+        ExitOnFailure(hr, "Failed to set string variable.");
     }
     else
     {
diff --git a/src/engine/EngineForApplication.h b/src/engine/EngineForApplication.h
index 1b755acc..e5e8f6d7 100644
--- a/src/engine/EngineForApplication.h
+++ b/src/engine/EngineForApplication.h
@@ -24,11 +24,11 @@ enum WM_BURN
 
 // structs
 
-struct BOOTSTRAPPER_ENGINE_CONTEXT
+typedef struct _BOOTSTRAPPER_ENGINE_CONTEXT
 {
     BURN_ENGINE_STATE* pEngineState;
     DWORD dwThreadId;
-};
+} BOOTSTRAPPER_ENGINE_CONTEXT;
 
 // function declarations
 
diff --git a/src/engine/EngineForExtension.cpp b/src/engine/EngineForExtension.cpp
new file mode 100644
index 00000000..9667dd18
--- /dev/null
+++ b/src/engine/EngineForExtension.cpp
@@ -0,0 +1,405 @@
+// 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.
+
+#include "precomp.h"
+
+static HRESULT BEEngineEscapeString(
+    __in BURN_EXTENSION_ENGINE_CONTEXT* /*pContext*/,
+    __in BUNDLE_EXTENSION_ENGINE_ESCAPESTRING_ARGS* pArgs,
+    __in BUNDLE_EXTENSION_ENGINE_ESCAPESTRING_RESULTS* pResults
+    )
+{
+    HRESULT hr = S_OK;
+    LPWSTR sczValue = NULL;
+    size_t cchRemaining = 0;
+    LPCWSTR wzIn = pArgs->wzIn;
+    LPWSTR wzOut = pResults->wzOut;
+    DWORD* pcchOut = &pResults->cchOut;
+
+    if (wzIn && *wzIn)
+    {
+        hr = VariableEscapeString(wzIn, &sczValue);
+        if (SUCCEEDED(hr))
+        {
+            if (wzOut)
+            {
+                hr = ::StringCchCopyExW(wzOut, *pcchOut, sczValue, NULL, &cchRemaining, STRSAFE_FILL_BEHIND_NULL);
+                if (STRSAFE_E_INSUFFICIENT_BUFFER == hr)
+                {
+                    hr = E_MOREDATA;
+                    ::StringCchLengthW(sczValue, STRSAFE_MAX_CCH, &cchRemaining);
+                    *pcchOut = cchRemaining;
+                }
+            }
+            else
+            {
+                ::StringCchLengthW(sczValue, STRSAFE_MAX_CCH, &cchRemaining);
+                *pcchOut = cchRemaining;
+            }
+        }
+    }
+    else
+    {
+        hr = E_INVALIDARG;
+    }
+
+    StrSecureZeroFreeString(sczValue);
+    return hr;
+}
+
+static HRESULT BEEngineEvaluateCondition(
+    __in BURN_EXTENSION_ENGINE_CONTEXT* pContext,
+    __in BUNDLE_EXTENSION_ENGINE_EVALUATECONDITION_ARGS* pArgs,
+    __in BUNDLE_EXTENSION_ENGINE_EVALUATECONDITION_RESULTS* pResults
+    )
+{
+    HRESULT hr = S_OK;
+    LPCWSTR wzCondition = pArgs->wzCondition;
+    BOOL* pf = &pResults->f;
+
+    if (wzCondition && *wzCondition)
+    {
+        hr = ConditionEvaluate(&pContext->pEngineState->variables, wzCondition, pf);
+    }
+    else
+    {
+        hr = E_INVALIDARG;
+    }
+
+    return hr;
+}
+
+static HRESULT BEEngineFormatString(
+    __in BURN_EXTENSION_ENGINE_CONTEXT* pContext,
+    __in BUNDLE_EXTENSION_ENGINE_FORMATSTRING_ARGS* pArgs,
+    __in BUNDLE_EXTENSION_ENGINE_FORMATSTRING_RESULTS* pResults
+    )
+{
+    HRESULT hr = S_OK;
+    LPWSTR sczValue = NULL;
+    DWORD cchValue = 0;
+    LPCWSTR wzIn = pArgs->wzIn;
+    LPWSTR wzOut = pResults->wzOut;
+    DWORD* pcchOut = &pResults->cchOut;
+
+    if (wzIn && *wzIn)
+    {
+        hr = VariableFormatString(&pContext->pEngineState->variables, wzIn, &sczValue, &cchValue);
+        if (SUCCEEDED(hr))
+        {
+            if (wzOut)
+            {
+                hr = ::StringCchCopyExW(wzOut, *pcchOut, sczValue, NULL, NULL, STRSAFE_FILL_BEHIND_NULL);
+                if (FAILED(hr))
+                {
+                    *pcchOut = cchValue;
+                    if (STRSAFE_E_INSUFFICIENT_BUFFER == hr)
+                    {
+                        hr = E_MOREDATA;
+                    }
+                }
+            }
+            else
+            {
+                hr = E_MOREDATA;
+                *pcchOut = cchValue;
+            }
+        }
+    }
+    else
+    {
+        hr = E_INVALIDARG;
+    }
+
+    StrSecureZeroFreeString(sczValue);
+    return hr;
+}
+
+static HRESULT BEEngineGetVariableNumeric(
+    __in BURN_EXTENSION_ENGINE_CONTEXT* pContext,
+    __in BUNDLE_EXTENSION_ENGINE_GETVARIABLENUMERIC_ARGS* pArgs,
+    __in BUNDLE_EXTENSION_ENGINE_GETVARIABLENUMERIC_RESULTS* pResults
+    )
+{
+    HRESULT hr = S_OK;
+    LPCWSTR wzVariable = pArgs->wzVariable;
+    LONGLONG* pllValue = &pResults->llValue;
+
+    if (wzVariable && *wzVariable)
+    {
+        hr = VariableGetNumeric(&pContext->pEngineState->variables, wzVariable, pllValue);
+    }
+    else
+    {
+        hr = E_INVALIDARG;
+    }
+
+    return hr;
+}
+
+static HRESULT BEEngineGetVariableString(
+    __in BURN_EXTENSION_ENGINE_CONTEXT* pContext,
+    __in BUNDLE_EXTENSION_ENGINE_GETVARIABLESTRING_ARGS* pArgs,
+    __in BUNDLE_EXTENSION_ENGINE_GETVARIABLESTRING_RESULTS* pResults
+    )
+{
+    HRESULT hr = S_OK;
+    LPWSTR sczValue = NULL;
+    size_t cchRemaining = 0;
+    LPCWSTR wzVariable = pArgs->wzVariable;
+    LPWSTR wzValue = pResults->wzValue;
+    DWORD* pcchValue = &pResults->cchValue;
+
+    if (wzVariable && *wzVariable)
+    {
+        hr = VariableGetString(&pContext->pEngineState->variables, wzVariable, &sczValue);
+        if (SUCCEEDED(hr))
+        {
+            if (wzValue)
+            {
+                hr = ::StringCchCopyExW(wzValue, *pcchValue, sczValue, NULL, &cchRemaining, STRSAFE_FILL_BEHIND_NULL);
+                if (STRSAFE_E_INSUFFICIENT_BUFFER == hr)
+                {
+                    hr = E_MOREDATA;
+
+                    ::StringCchLengthW(sczValue, STRSAFE_MAX_CCH, &cchRemaining);
+                    *pcchValue = cchRemaining + 1;
+                }
+            }
+            else
+            {
+                hr = E_MOREDATA;
+
+                ::StringCchLengthW(sczValue, STRSAFE_MAX_CCH, &cchRemaining);
+                *pcchValue = cchRemaining + 1;
+            }
+        }
+    }
+    else
+    {
+        hr = E_INVALIDARG;
+    }
+
+    StrSecureZeroFreeString(sczValue);
+    return hr;
+}
+
+static HRESULT BEEngineGetVariableVersion(
+    __in BURN_EXTENSION_ENGINE_CONTEXT* pContext,
+    __in BUNDLE_EXTENSION_ENGINE_GETVARIABLEVERSION_ARGS* pArgs,
+    __in BUNDLE_EXTENSION_ENGINE_GETVARIABLEVERSION_RESULTS* pResults
+    )
+{
+    HRESULT hr = S_OK;
+    LPCWSTR wzVariable = pArgs->wzVariable;
+    DWORD64* pqwValue = &pResults->qwValue;
+
+    if (wzVariable && *wzVariable)
+    {
+        hr = VariableGetVersion(&pContext->pEngineState->variables, wzVariable, pqwValue);
+    }
+    else
+    {
+        hr = E_INVALIDARG;
+    }
+
+    return hr;
+}
+
+static HRESULT BEEngineLog(
+    __in BURN_EXTENSION_ENGINE_CONTEXT* /*pContext*/,
+    __in BUNDLE_EXTENSION_ENGINE_LOG_ARGS* pArgs,
+    __in BUNDLE_EXTENSION_ENGINE_LOG_RESULTS* /*pResults*/
+    )
+{
+    HRESULT hr = S_OK;
+    REPORT_LEVEL rl = REPORT_NONE;
+    BUNDLE_EXTENSION_LOG_LEVEL level = pArgs->level;
+    LPCWSTR wzMessage = pArgs->wzMessage;
+
+    switch (level)
+    {
+    case BUNDLE_EXTENSION_LOG_LEVEL_STANDARD:
+        rl = REPORT_STANDARD;
+        break;
+
+    case BUNDLE_EXTENSION_LOG_LEVEL_VERBOSE:
+        rl = REPORT_VERBOSE;
+        break;
+
+    case BUNDLE_EXTENSION_LOG_LEVEL_DEBUG:
+        rl = REPORT_DEBUG;
+        break;
+
+    case BUNDLE_EXTENSION_LOG_LEVEL_ERROR:
+        rl = REPORT_ERROR;
+        break;
+
+    default:
+        ExitFunction1(hr = E_INVALIDARG);
+    }
+
+    hr = LogStringLine(rl, "%ls", wzMessage);
+    ExitOnFailure(hr, "Failed to log Bundle Extension message.");
+
+LExit:
+    return hr;
+}
+
+static HRESULT BEEngineSetVariableLiteralString(
+    __in BURN_EXTENSION_ENGINE_CONTEXT* pContext,
+    __in const BUNDLE_EXTENSION_ENGINE_SETVARIABLELITERALSTRING_ARGS* pArgs,
+    __in BUNDLE_EXTENSION_ENGINE_SETVARIABLELITERALSTRING_RESULTS* /*pResults*/
+    )
+{
+    HRESULT hr = S_OK;
+    LPCWSTR wzVariable = pArgs->wzVariable;
+    LPCWSTR wzValue = pArgs->wzValue;
+
+    if (wzVariable && *wzVariable)
+    {
+        hr = VariableSetLiteralString(&pContext->pEngineState->variables, wzVariable, wzValue, FALSE);
+        ExitOnFailure(hr, "Failed to set literal string variable.");
+    }
+    else
+    {
+        hr = E_INVALIDARG;
+        ExitOnFailure(hr, "Bundle Extension did not provide variable name.");
+    }
+
+LExit:
+    return hr;
+}
+
+static HRESULT BEEngineSetVariableNumeric(
+    __in BURN_EXTENSION_ENGINE_CONTEXT* pContext,
+    __in const BUNDLE_EXTENSION_ENGINE_SETVARIABLENUMERIC_ARGS* pArgs,
+    __in BUNDLE_EXTENSION_ENGINE_SETVARIABLENUMERIC_RESULTS* /*pResults*/
+    )
+{
+    HRESULT hr = S_OK;
+    LPCWSTR wzVariable = pArgs->wzVariable;
+    LONGLONG llValue = pArgs->llValue;
+
+    if (wzVariable && *wzVariable)
+    {
+        hr = VariableSetNumeric(&pContext->pEngineState->variables, wzVariable, llValue, FALSE);
+        ExitOnFailure(hr, "Failed to set numeric variable.");
+    }
+    else
+    {
+        hr = E_INVALIDARG;
+        ExitOnFailure(hr, "Bundle Extension did not provide variable name.");
+    }
+
+LExit:
+    return hr;
+}
+
+static HRESULT BEEngineSetVariableString(
+    __in BURN_EXTENSION_ENGINE_CONTEXT* pContext,
+    __in const BUNDLE_EXTENSION_ENGINE_SETVARIABLESTRING_ARGS* pArgs,
+    __in BUNDLE_EXTENSION_ENGINE_SETVARIABLESTRING_RESULTS* /*pResults*/
+    )
+{
+    HRESULT hr = S_OK;
+    LPCWSTR wzVariable = pArgs->wzVariable;
+    LPCWSTR wzValue = pArgs->wzValue;
+
+    if (wzVariable && *wzVariable)
+    {
+        hr = VariableSetString(&pContext->pEngineState->variables, wzVariable, wzValue, FALSE);
+        ExitOnFailure(hr, "Failed to set string variable.");
+    }
+    else
+    {
+        hr = E_INVALIDARG;
+        ExitOnFailure(hr, "Bundle Extension did not provide variable name.");
+    }
+
+LExit:
+    return hr;
+}
+
+static HRESULT BEEngineSetVariableVersion(
+    __in BURN_EXTENSION_ENGINE_CONTEXT* pContext,
+    __in const BUNDLE_EXTENSION_ENGINE_SETVARIABLEVERSION_ARGS* pArgs,
+    __in BUNDLE_EXTENSION_ENGINE_SETVARIABLEVERSION_RESULTS* /*pResults*/
+    )
+{
+    HRESULT hr = S_OK;
+    LPCWSTR wzVariable = pArgs->wzVariable;
+    DWORD64 qwValue = pArgs->qwValue;
+
+    if (wzVariable && *wzVariable)
+    {
+        hr = VariableSetVersion(&pContext->pEngineState->variables, wzVariable, qwValue, FALSE);
+        ExitOnFailure(hr, "Failed to set version variable.");
+    }
+    else
+    {
+        hr = E_INVALIDARG;
+        ExitOnFailure(hr, "Bundle Extension did not provide variable name.");
+    }
+
+LExit:
+    return hr;
+}
+
+HRESULT WINAPI EngineForExtensionProc(
+    __in BUNDLE_EXTENSION_ENGINE_MESSAGE message,
+    __in const LPVOID pvArgs,
+    __inout LPVOID pvResults,
+    __in_opt LPVOID pvContext
+    )
+{
+    HRESULT hr = S_OK;
+    BURN_EXTENSION_ENGINE_CONTEXT* pContext = reinterpret_cast<BURN_EXTENSION_ENGINE_CONTEXT*>(pvContext);
+
+    if (!pContext || !pvArgs || !pvResults)
+    {
+        ExitFunction1(hr = E_INVALIDARG);
+    }
+
+    switch (message)
+    {
+    case BUNDLE_EXTENSION_ENGINE_MESSAGE_ESCAPESTRING:
+        hr = BEEngineEscapeString(pContext, reinterpret_cast<BUNDLE_EXTENSION_ENGINE_ESCAPESTRING_ARGS*>(pvArgs), reinterpret_cast<BUNDLE_EXTENSION_ENGINE_ESCAPESTRING_RESULTS*>(pvResults));
+        break;
+    case BUNDLE_EXTENSION_ENGINE_MESSAGE_EVALUATECONDITION:
+        hr = BEEngineEvaluateCondition(pContext, reinterpret_cast<BUNDLE_EXTENSION_ENGINE_EVALUATECONDITION_ARGS*>(pvArgs), reinterpret_cast<BUNDLE_EXTENSION_ENGINE_EVALUATECONDITION_RESULTS*>(pvResults));
+        break;
+    case BUNDLE_EXTENSION_ENGINE_MESSAGE_FORMATSTRING:
+        hr = BEEngineFormatString(pContext, reinterpret_cast<BUNDLE_EXTENSION_ENGINE_FORMATSTRING_ARGS*>(pvArgs), reinterpret_cast<BUNDLE_EXTENSION_ENGINE_FORMATSTRING_RESULTS*>(pvResults));
+        break;
+    case BUNDLE_EXTENSION_ENGINE_MESSAGE_GETVARIABLENUMERIC:
+        hr = BEEngineGetVariableNumeric(pContext, reinterpret_cast<BUNDLE_EXTENSION_ENGINE_GETVARIABLENUMERIC_ARGS*>(pvArgs), reinterpret_cast<BUNDLE_EXTENSION_ENGINE_GETVARIABLENUMERIC_RESULTS*>(pvResults));
+        break;
+    case BUNDLE_EXTENSION_ENGINE_MESSAGE_GETVARIABLESTRING:
+        hr = BEEngineGetVariableString(pContext, reinterpret_cast<BUNDLE_EXTENSION_ENGINE_GETVARIABLESTRING_ARGS*>(pvArgs), reinterpret_cast<BUNDLE_EXTENSION_ENGINE_GETVARIABLESTRING_RESULTS*>(pvResults));
+        break;
+    case BUNDLE_EXTENSION_ENGINE_MESSAGE_GETVARIABLEVERSION:
+        hr = BEEngineGetVariableVersion(pContext, reinterpret_cast<BUNDLE_EXTENSION_ENGINE_GETVARIABLEVERSION_ARGS*>(pvArgs), reinterpret_cast<BUNDLE_EXTENSION_ENGINE_GETVARIABLEVERSION_RESULTS*>(pvResults));
+        break;
+    case BUNDLE_EXTENSION_ENGINE_MESSAGE_LOG:
+        hr = BEEngineLog(pContext, reinterpret_cast<BUNDLE_EXTENSION_ENGINE_LOG_ARGS*>(pvArgs), reinterpret_cast<BUNDLE_EXTENSION_ENGINE_LOG_RESULTS*>(pvResults));
+        break;
+    case BUNDLE_EXTENSION_ENGINE_MESSAGE_SETVARIABLELITERALSTRING:
+        hr = BEEngineSetVariableLiteralString(pContext, reinterpret_cast<BUNDLE_EXTENSION_ENGINE_SETVARIABLELITERALSTRING_ARGS*>(pvArgs), reinterpret_cast<BUNDLE_EXTENSION_ENGINE_SETVARIABLELITERALSTRING_RESULTS*>(pvResults));
+        break;
+    case BUNDLE_EXTENSION_ENGINE_MESSAGE_SETVARIABLENUMERIC:
+        hr = BEEngineSetVariableNumeric(pContext, reinterpret_cast<BUNDLE_EXTENSION_ENGINE_SETVARIABLENUMERIC_ARGS*>(pvArgs), reinterpret_cast<BUNDLE_EXTENSION_ENGINE_SETVARIABLENUMERIC_RESULTS*>(pvResults));
+        break;
+    case BUNDLE_EXTENSION_ENGINE_MESSAGE_SETVARIABLESTRING:
+        hr = BEEngineSetVariableString(pContext, reinterpret_cast<BUNDLE_EXTENSION_ENGINE_SETVARIABLESTRING_ARGS*>(pvArgs), reinterpret_cast<BUNDLE_EXTENSION_ENGINE_SETVARIABLESTRING_RESULTS*>(pvResults));
+        break;
+    case BUNDLE_EXTENSION_ENGINE_MESSAGE_SETVARIABLEVERSION:
+        hr = BEEngineSetVariableVersion(pContext, reinterpret_cast<BUNDLE_EXTENSION_ENGINE_SETVARIABLEVERSION_ARGS*>(pvArgs), reinterpret_cast<BUNDLE_EXTENSION_ENGINE_SETVARIABLEVERSION_RESULTS*>(pvResults));
+        break;
+    default:
+        hr = E_NOTIMPL;
+        break;
+    }
+
+LExit:
+    return hr;
+}
diff --git a/src/engine/EngineForExtension.h b/src/engine/EngineForExtension.h
new file mode 100644
index 00000000..bad5f08a
--- /dev/null
+++ b/src/engine/EngineForExtension.h
@@ -0,0 +1,27 @@
+#pragma once
+// 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.
+
+
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
+// structs
+
+typedef struct _BURN_EXTENSION_ENGINE_CONTEXT
+{
+    BURN_ENGINE_STATE* pEngineState;
+} BURN_EXTENSION_ENGINE_CONTEXT;
+
+// function declarations
+
+HRESULT WINAPI EngineForExtensionProc(
+    __in BUNDLE_EXTENSION_ENGINE_MESSAGE message,
+    __in const LPVOID pvArgs,
+    __inout LPVOID pvResults,
+    __in_opt LPVOID pvContext
+    );
+
+#if defined(__cplusplus)
+}
+#endif
diff --git a/src/engine/burnextension.cpp b/src/engine/burnextension.cpp
new file mode 100644
index 00000000..99673cd9
--- /dev/null
+++ b/src/engine/burnextension.cpp
@@ -0,0 +1,184 @@
+// 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.
+
+#include "precomp.h"
+
+// function definitions
+
+/*******************************************************************
+ BurnExtensionParseFromXml - 
+
+*******************************************************************/
+EXTERN_C HRESULT BurnExtensionParseFromXml(
+    __in BURN_EXTENSIONS* pBurnExtensions,
+    __in BURN_PAYLOADS* pBaPayloads,
+    __in IXMLDOMNode* pixnBundle
+    )
+{
+    HRESULT hr = S_OK;
+    IXMLDOMNodeList* pixnNodes = NULL;
+    IXMLDOMNode* pixnNode = NULL;
+    DWORD cNodes = 0;
+
+    // Select BundleExtension nodes.
+    hr = XmlSelectNodes(pixnBundle, L"BundleExtension", &pixnNodes);
+    ExitOnFailure(hr, "Failed to select BundleExtension nodes.");
+
+    // Get BundleExtension node count.
+    hr = pixnNodes->get_length((long*)&cNodes);
+    ExitOnFailure(hr, "Failed to get BundleExtension node count.");
+
+    if (!cNodes)
+    {
+        ExitFunction();
+    }
+
+    // Allocate memory for BundleExtensions.
+    pBurnExtensions->rgExtensions = (BURN_EXTENSION*)MemAlloc(sizeof(BURN_EXTENSION) * cNodes, TRUE);
+    ExitOnNull(pBurnExtensions->rgExtensions, hr, E_OUTOFMEMORY, "Failed to allocate memory for BundleExtension structs.");
+
+    pBurnExtensions->cExtensions = cNodes;
+
+    // parse search elements
+    for (DWORD i = 0; i < cNodes; ++i)
+    {
+        BURN_EXTENSION* pExtension = &pBurnExtensions->rgExtensions[i];
+
+        hr = XmlNextElement(pixnNodes, &pixnNode, NULL);
+        ExitOnFailure(hr, "Failed to get next node.");
+
+        // @Id
+        hr = XmlGetAttributeEx(pixnNode, L"Id", &pExtension->sczId);
+        ExitOnFailure(hr, "Failed to get @Id.");
+
+        // @EntryPayloadId
+        hr = XmlGetAttributeEx(pixnNode, L"EntryPayloadId", &pExtension->sczEntryPayloadId);
+        ExitOnFailure(hr, "Failed to get @EntryPayloadId.");
+
+        hr = PayloadFindById(pBaPayloads, pExtension->sczEntryPayloadId, &pExtension->pEntryPayload);
+        ExitOnFailure(hr, "Failed to find BundleExtension EntryPayload '%ls'.", pExtension->sczEntryPayloadId);
+
+        // prepare next iteration
+        ReleaseNullObject(pixnNode);
+    }
+
+    hr = S_OK;
+
+LExit:
+    ReleaseObject(pixnNode);
+    ReleaseObject(pixnNodes);
+
+    return hr;
+}
+
+/*******************************************************************
+ BurnExtensionUninitialize - 
+
+*******************************************************************/
+EXTERN_C void BurnExtensionUninitialize(
+    __in BURN_EXTENSIONS* pBurnExtensions
+    )
+{
+    if (pBurnExtensions->rgExtensions)
+    {
+        for (DWORD i = 0; i < pBurnExtensions->cExtensions; ++i)
+        {
+            BURN_EXTENSION* pExtension = &pBurnExtensions->rgExtensions[i];
+
+            ReleaseStr(pExtension->sczEntryPayloadId);
+            ReleaseStr(pExtension->sczId);
+        }
+        MemFree(pBurnExtensions->rgExtensions);
+    }
+
+    // clear struct
+    memset(pBurnExtensions, 0, sizeof(BURN_EXTENSIONS));
+}
+
+/*******************************************************************
+ BurnExtensionLoad - 
+
+*******************************************************************/
+EXTERN_C HRESULT BurnExtensionLoad(
+    __in BURN_EXTENSIONS * pBurnExtensions,
+    __in BURN_EXTENSION_ENGINE_CONTEXT* pEngineContext
+    )
+{
+    HRESULT hr = S_OK;
+    BUNDLE_EXTENSION_CREATE_ARGS args = { };
+    BUNDLE_EXTENSION_CREATE_RESULTS results = { };
+
+    if (!pBurnExtensions->rgExtensions || !pBurnExtensions->cExtensions)
+    {
+        ExitFunction();
+    }
+
+    for (DWORD i = 0; i < pBurnExtensions->cExtensions; ++i)
+    {
+        BURN_EXTENSION* pExtension = &pBurnExtensions->rgExtensions[i];
+
+        memset(&args, 0, sizeof(BUNDLE_EXTENSION_CREATE_ARGS));
+        memset(&results, 0, sizeof(BUNDLE_EXTENSION_CREATE_RESULTS));
+
+        args.cbSize = sizeof(BUNDLE_EXTENSION_CREATE_ARGS);
+        args.pfnBundleExtensionEngineProc = EngineForExtensionProc;
+        args.pvBundleExtensionEngineProcContext = pEngineContext;
+        args.qwEngineAPIVersion = MAKEQWORDVERSION(0, 0, 0, 1); // TODO: need to decide whether to keep this, and if so when to update it.
+
+        results.cbSize = sizeof(BUNDLE_EXTENSION_CREATE_RESULTS);
+
+        // Load BundleExtension DLL.
+        pExtension->hBextModule = ::LoadLibraryExW(pExtension->pEntryPayload->sczLocalFilePath, NULL, LOAD_WITH_ALTERED_SEARCH_PATH);
+        ExitOnNullWithLastError(pExtension->hBextModule, hr, "Failed to load BundleExtension DLL '%ls': '%ls'.", pExtension->sczId, pExtension->pEntryPayload->sczLocalFilePath);
+
+        // Get BundleExtensionCreate entry-point.
+        PFN_BUNDLE_EXTENSION_CREATE pfnCreate = (PFN_BUNDLE_EXTENSION_CREATE)::GetProcAddress(pExtension->hBextModule, "BundleExtensionCreate");
+        ExitOnNullWithLastError(pfnCreate, hr, "Failed to get BundleExtensionCreate entry-point '%ls'.", pExtension->sczId);
+
+        // Create BundleExtension.
+        hr = pfnCreate(&args, &results);
+        ExitOnFailure(hr, "Failed to create BundleExtension '%ls'.", pExtension->sczId);
+
+        pExtension->pfnBurnExtensionProc = results.pfnBundleExtensionProc;
+        pExtension->pvBurnExtensionProcContext = results.pvBundleExtensionProcContext;
+    }
+
+LExit:
+    return hr;
+}
+
+/*******************************************************************
+ BurnExtensionUnload - 
+
+*******************************************************************/
+EXTERN_C void BurnExtensionUnload(
+    __in BURN_EXTENSIONS * pBurnExtensions
+    )
+{
+    HRESULT hr = S_OK;
+
+    if (pBurnExtensions->rgExtensions)
+    {
+        for (DWORD i = 0; i < pBurnExtensions->cExtensions; ++i)
+        {
+            BURN_EXTENSION* pExtension = &pBurnExtensions->rgExtensions[i];
+
+            if (pExtension->hBextModule)
+            {
+                // Get BundleExtensionDestroy entry-point and call it if it exists.
+                PFN_BUNDLE_EXTENSION_DESTROY pfnDestroy = (PFN_BUNDLE_EXTENSION_DESTROY)::GetProcAddress(pExtension->hBextModule, "BundleExtensionDestroy");
+                if (pfnDestroy)
+                {
+                    pfnDestroy();
+                }
+
+                // Free BundleExtension DLL.
+                if (!::FreeLibrary(pExtension->hBextModule))
+                {
+                    hr = HRESULT_FROM_WIN32(::GetLastError());
+                    TraceError(hr, "Failed to unload BundleExtension DLL.");
+                }
+                pExtension->hBextModule = NULL;
+            }
+        }
+    }
+}
diff --git a/src/engine/burnextension.h b/src/engine/burnextension.h
new file mode 100644
index 00000000..43c8afe6
--- /dev/null
+++ b/src/engine/burnextension.h
@@ -0,0 +1,51 @@
+#pragma once
+// 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.
+
+#define BEEAPI HRESULT __stdcall
+
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
+// structs
+
+typedef struct _BURN_EXTENSION_ENGINE_CONTEXT BURN_EXTENSION_ENGINE_CONTEXT;
+
+typedef struct _BURN_EXTENSION
+{
+    LPWSTR sczEntryPayloadId;
+    LPWSTR sczId;
+
+    BURN_PAYLOAD* pEntryPayload;
+
+    HMODULE hBextModule;
+    PFN_BUNDLE_EXTENSION_PROC pfnBurnExtensionProc;
+    LPVOID pvBurnExtensionProcContext;
+} BURN_EXTENSION;
+
+typedef struct _BURN_EXTENSIONS
+{
+    BURN_EXTENSION* rgExtensions;
+    DWORD cExtensions;
+} BURN_EXTENSIONS;
+
+// functions
+
+HRESULT BurnExtensionParseFromXml(
+    __in BURN_EXTENSIONS* pBurnExtensions,
+    __in BURN_PAYLOADS* pBaPayloads,
+    __in IXMLDOMNode* pixnBundle
+    );
+void BurnExtensionUninitialize(
+    __in BURN_EXTENSIONS* pBurnExtensions
+    );
+HRESULT BurnExtensionLoad(
+    __in BURN_EXTENSIONS* pBurnExtensions,
+    __in BURN_EXTENSION_ENGINE_CONTEXT* pEngineContext
+    );
+void BurnExtensionUnload(
+    __in BURN_EXTENSIONS* pBurnExtensions
+    );
+#if defined(__cplusplus)
+}
+#endif
diff --git a/src/engine/core.h b/src/engine/core.h
index 6a6da2b1..544c1786 100644
--- a/src/engine/core.h
+++ b/src/engine/core.h
@@ -103,6 +103,7 @@ typedef struct _BURN_ENGINE_STATE
     BURN_PACKAGES packages;
     BURN_UPDATE update;
     BURN_APPROVED_EXES approvedExes;
+    BURN_EXTENSIONS extensions;
 
     HWND hMessageWindow;
     HANDLE hMessageWindowThread;
diff --git a/src/engine/engine.cpp b/src/engine/engine.cpp
index 341fd471..488dbfe8 100644
--- a/src/engine/engine.cpp
+++ b/src/engine/engine.cpp
@@ -352,6 +352,8 @@ static void UninitializeEngineState(
 
     ReleaseHandle(pEngineState->hMessageWindowThread);
 
+    BurnExtensionUninitialize(&pEngineState->extensions);
+
     ::DeleteCriticalSection(&pEngineState->userExperience.csEngineActive);
     UserExperienceUninitialize(&pEngineState->userExperience);
 
@@ -493,6 +495,7 @@ static HRESULT RunNormal(
     HANDLE hPipesCreatedEvent = NULL;
     BOOL fContinueExecution = TRUE;
     BOOL fReloadApp = FALSE;
+    BURN_EXTENSION_ENGINE_CONTEXT extensionEngineContext = { };
 
     // Initialize logging.
     hr = LoggingOpen(&pEngineState->log, &pEngineState->variables, pEngineState->command.display, pEngineState->registration.sczDisplayName);
@@ -537,6 +540,13 @@ static HRESULT RunNormal(
         ExitOnFailure(hr, "Failed to set layout directory variable to value provided from command-line.");
     }
 
+    // Setup the extension engine.
+    extensionEngineContext.pEngineState = pEngineState;
+
+    // Load the extensions.
+    hr = BurnExtensionLoad(&pEngineState->extensions, &extensionEngineContext);
+    ExitOnFailure(hr, "Failed to load BundleExtensions.");
+
     do
     {
         fReloadApp = FALSE;
@@ -546,6 +556,8 @@ static HRESULT RunNormal(
     } while (fReloadApp);
 
 LExit:
+    BurnExtensionUnload(&pEngineState->extensions);
+
     // If the message window is still around, close it.
     UiCloseMessageWindow(pEngineState);
 
diff --git a/src/engine/engine.vcxproj b/src/engine/engine.vcxproj
index 499fcd4d..c2e8f34c 100644
--- a/src/engine/engine.vcxproj
+++ b/src/engine/engine.vcxproj
@@ -2,7 +2,7 @@
 <!-- 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. -->
 
 <Project DefaultTargets="Build" ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
-  <Import Project="..\..\packages\WixToolset.BootstrapperCore.Native.4.0.12\build\WixToolset.BootstrapperCore.Native.props" Condition="Exists('..\..\packages\WixToolset.BootstrapperCore.Native.4.0.12\build\WixToolset.BootstrapperCore.Native.props')" />
+  <Import Project="..\..\packages\WixToolset.BootstrapperCore.Native.4.0.13\build\WixToolset.BootstrapperCore.Native.props" Condition="Exists('..\..\packages\WixToolset.BootstrapperCore.Native.4.0.13\build\WixToolset.BootstrapperCore.Native.props')" />
   <Import Project="..\..\packages\WixToolset.DUtil.4.0.18\build\WixToolset.DUtil.props" Condition="Exists('..\..\packages\WixToolset.DUtil.4.0.18\build\WixToolset.DUtil.props')" />
 
   <ItemGroup Label="ProjectConfigurations">
@@ -50,10 +50,12 @@
     <ClCompile Include="apply.cpp" />
     <ClCompile Include="approvedexe.cpp" />
     <ClCompile Include="bitsengine.cpp" />
+    <ClCompile Include="burnextension.cpp" />
     <ClCompile Include="catalog.cpp" />
     <ClCompile Include="detect.cpp" />
     <ClCompile Include="embedded.cpp" />
     <ClCompile Include="EngineForApplication.cpp" />
+    <ClCompile Include="EngineForExtension.cpp" />
     <ClCompile Include="cabextract.cpp" />
     <ClCompile Include="cache.cpp" />
     <ClCompile Include="condition.cpp" />
@@ -91,14 +93,10 @@
   </ItemGroup>
 
   <ItemGroup>
-    <ClInclude Include="..\inc\BootstrapperApplication.h" />
-    <ClInclude Include="..\inc\BootstrapperEngine.h" />
-  </ItemGroup>
-
-  <ItemGroup>
     <ClInclude Include="apply.h" />
     <ClInclude Include="approvedexe.h" />
     <ClInclude Include="bitsengine.h" />
+    <ClInclude Include="burnextension.h" />
     <ClInclude Include="cabextract.h" />
     <ClInclude Include="cache.h" />
     <ClInclude Include="catalog.h" />
@@ -110,6 +108,7 @@
     <ClInclude Include="elevation.h" />
     <ClInclude Include="embedded.h" />
     <ClInclude Include="EngineForApplication.h" />
+    <ClInclude Include="EngineForExtension.h" />
     <ClInclude Include="exeengine.h" />
     <ClInclude Include="inc\engine.h" />
     <ClInclude Include="logging.h" />
@@ -167,7 +166,7 @@ rc.exe -fo "$(OutDir)engine.res" "$(IntDir)engine.messages.rc"</Command>
     <PropertyGroup>
       <ErrorText>This project references NuGet package(s) that are missing on this computer. Use NuGet Package Restore to download them.  For more information, see http://go.microsoft.com/fwlink/?LinkID=322105. The missing file is {0}.</ErrorText>
     </PropertyGroup>
-    <Error Condition="!Exists('..\..\packages\WixToolset.BootstrapperCore.Native.4.0.12\build\WixToolset.BootstrapperCore.Native.props')" Text="$([System.String]::Format('$(ErrorText)', '..\..\packages\WixToolset.BootstrapperCore.Native.4.0.12\build\WixToolset.BootstrapperCore.Native.props'))" />
+    <Error Condition="!Exists('..\..\packages\WixToolset.BootstrapperCore.Native.4.0.13\build\WixToolset.BootstrapperCore.Native.props')" Text="$([System.String]::Format('$(ErrorText)', '..\..\packages\WixToolset.BootstrapperCore.Native.4.0.13\build\WixToolset.BootstrapperCore.Native.props'))" />
     <Error Condition="!Exists('..\..\packages\WixToolset.DUtil.4.0.18\build\WixToolset.DUtil.props')" Text="$([System.String]::Format('$(ErrorText)', '..\..\packages\WixToolset.DUtil.4.0.18\build\WixToolset.DUtil.props'))" />
     <Error Condition="!Exists('..\..\packages\Nerdbank.GitVersioning.2.1.65\build\Nerdbank.GitVersioning.targets')" Text="$([System.String]::Format('$(ErrorText)', '..\..\packages\Nerdbank.GitVersioning.2.1.65\build\Nerdbank.GitVersioning.targets'))" />
   </Target>
diff --git a/src/engine/manifest.cpp b/src/engine/manifest.cpp
index c2214a89..a20f1980 100644
--- a/src/engine/manifest.cpp
+++ b/src/engine/manifest.cpp
@@ -116,6 +116,10 @@ extern "C" HRESULT ManifestLoadXmlFromBuffer(
     hr = ApprovedExesParseFromXml(&pEngineState->approvedExes, pixeBundle);
     ExitOnFailure(hr, "Failed to parse approved exes.");
 
+    // parse extensions
+    hr = BurnExtensionParseFromXml(&pEngineState->extensions, &pEngineState->userExperience.payloads, pixeBundle);
+    ExitOnFailure(hr, "Failed to parse extensions.");
+
 LExit:
     ReleaseObject(pixnChain);
     ReleaseObject(pixnLog);
diff --git a/src/engine/packages.config b/src/engine/packages.config
index 01a9390c..75a6476b 100644
--- a/src/engine/packages.config
+++ b/src/engine/packages.config
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
   <package id="Nerdbank.GitVersioning" version="2.1.65" targetFramework="native" developmentDependency="true" />
-  <package id="WixToolset.BootstrapperCore.Native" version="4.0.12" targetFramework="native" />
+  <package id="WixToolset.BootstrapperCore.Native" version="4.0.13" targetFramework="native" />
   <package id="WixToolset.DUtil" version="4.0.18" targetFramework="native" />
 </packages>
\ No newline at end of file
diff --git a/src/engine/precomp.h b/src/engine/precomp.h
index 477dc310..780822a1 100644
--- a/src/engine/precomp.h
+++ b/src/engine/precomp.h
@@ -61,6 +61,8 @@
 
 #include "BootstrapperEngine.h"
 #include "BootstrapperApplication.h"
+#include "BundleExtensionEngine.h"
+#include "BundleExtension.h"
 
 #include "platform.h"
 #include "variant.h"
@@ -73,6 +75,7 @@
 #include "catalog.h"
 #include "payload.h"
 #include "cabextract.h"
+#include "burnextension.h"
 #include "userexperience.h"
 #include "package.h"
 #include "update.h"
@@ -100,4 +103,5 @@
 #include "netfxchainer.h"
 
 #include "EngineForApplication.h"
+#include "EngineForExtension.h"
 #include "engine.messages.h"
diff --git a/src/engine/userexperience.cpp b/src/engine/userexperience.cpp
index 8d5271aa..26b20f39 100644
--- a/src/engine/userexperience.cpp
+++ b/src/engine/userexperience.cpp
@@ -103,7 +103,7 @@ extern "C" HRESULT UserExperienceLoad(
 
     // Load BA DLL.
     pUserExperience->hUXModule = ::LoadLibraryExW(pUserExperience->payloads.rgPayloads[0].sczLocalFilePath, NULL, LOAD_WITH_ALTERED_SEARCH_PATH);
-    ExitOnNullWithLastError(pUserExperience->hUXModule, hr, "Failed to load UX DLL.");
+    ExitOnNullWithLastError(pUserExperience->hUXModule, hr, "Failed to load BA DLL.");
 
     // Get BootstrapperApplicationCreate entry-point.
     PFN_BOOTSTRAPPER_APPLICATION_CREATE pfnCreate = (PFN_BOOTSTRAPPER_APPLICATION_CREATE)::GetProcAddress(pUserExperience->hUXModule, "BootstrapperApplicationCreate");
diff --git a/src/engine/userexperience.h b/src/engine/userexperience.h
index 27a94115..bec6d292 100644
--- a/src/engine/userexperience.h
+++ b/src/engine/userexperience.h
@@ -15,7 +15,7 @@ const DWORD MB_RETRYTRYAGAIN = 0xF;
 
 // structs
 
-struct BOOTSTRAPPER_ENGINE_CONTEXT;
+typedef struct _BOOTSTRAPPER_ENGINE_CONTEXT BOOTSTRAPPER_ENGINE_CONTEXT;
 
 typedef struct _BURN_USER_EXPERIENCE
 {
diff --git a/src/engine/variable.cpp b/src/engine/variable.cpp
index 7377b116..8b1fd279 100644
--- a/src/engine/variable.cpp
+++ b/src/engine/variable.cpp
@@ -309,7 +309,7 @@ extern "C" HRESULT VariablesParseFromXml(
     hr = pixnNodes->get_length((long*)&cNodes);
     ExitOnFailure(hr, "Failed to get variable node count.");
 
-    // parse package elements
+    // parse variable elements
     for (DWORD i = 0; i < cNodes; ++i)
     {
         hr = XmlNextElement(pixnNodes, &pixnNode, NULL);