1 files changed, 1035 insertions, 113 deletions

diff --git a/src/api/burn/balutil/BalBootstrapperEngine.cpp b/src/api/burn/balutil/BalBootstrapperEngine.cpp
index be53c6b9..b924906e 100644
--- a/src/api/burn/balutil/BalBootstrapperEngine.cpp
+++ b/src/api/burn/balutil/BalBootstrapperEngine.cpp
@@ -2,7 +2,6 @@
 
 #include "precomp.h"
 
-
 class CBalBootstrapperEngine : public IBootstrapperEngine
 {
 public: // IUnknown
@@ -64,18 +63,44 @@ public: // IBootstrapperEngine
         HRESULT hr = S_OK;
         BAENGINE_GETPACKAGECOUNT_ARGS args = { };
         BAENGINE_GETPACKAGECOUNT_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
+        SIZE_T iBuffer = 0;
 
         ExitOnNull(pcPackages, hr, E_INVALIDARG, "pcPackages is required");
 
-        args.cbSize = sizeof(args);
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of GetPackageCount args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of GetPackageCount results.");
+
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_GETPACKAGECOUNT, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA GetPackageCount failed.");
 
-        results.cbSize = sizeof(results);
+        // Read results.
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, &results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to read value length from GetPackageCount results.");
 
-        hr = m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_GETPACKAGECOUNT, &args, &results, m_pvBAEngineProcContext);
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, (DWORD*)&results.cPackages);
+        ExitOnFailure(hr, "Failed to read value length from GetPackageCount results.");
 
         *pcPackages = results.cPackages;
 
     LExit:
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
         return hr;
     }
 
@@ -87,20 +112,50 @@ public: // IBootstrapperEngine
         HRESULT hr = S_OK;
         BAENGINE_GETVARIABLENUMERIC_ARGS args = { };
         BAENGINE_GETVARIABLENUMERIC_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
+        SIZE_T iBuffer = 0;
+        LPWSTR sczValue = NULL;
 
         ExitOnNull(pllValue, hr, E_INVALIDARG, "pllValue is required");
 
-        args.cbSize = sizeof(args);
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
         args.wzVariable = wzVariable;
 
-        results.cbSize = sizeof(results);
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of GetVariableNumeric args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzVariable);
+        ExitOnFailure(hr, "Failed to write variable name of GetVariableNumeric args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of GetVariableNumeric results.");
 
-        hr = m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_GETVARIABLENUMERIC, &args, &results, m_pvBAEngineProcContext);
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_GETVARIABLENUMERIC, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA GetVariableNumeric failed.");
+
+        // Read results.
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, &results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to read value length from GetVariableNumeric results.");
+
+        hr = BuffReadNumber64(rpc.pbData, rpc.cbData, &iBuffer, (DWORD64*)&results.llValue);
+        ExitOnFailure(hr, "Failed to read value length from GetVariableNumeric results.");
 
         *pllValue = results.llValue;
 
     LExit:
-        SecureZeroMemory(&results, sizeof(results));
+        ReleaseStr(sczValue);
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
         return hr;
     }
 
@@ -113,21 +168,69 @@ public: // IBootstrapperEngine
         HRESULT hr = S_OK;
         BAENGINE_GETVARIABLESTRING_ARGS args = { };
         BAENGINE_GETVARIABLESTRING_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
+        SIZE_T iBuffer = 0;
+        LPWSTR sczValue = NULL;
 
         ExitOnNull(pcchValue, hr, E_INVALIDARG, "pcchValue is required");
 
-        args.cbSize = sizeof(args);
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
         args.wzVariable = wzVariable;
 
-        results.cbSize = sizeof(results);
-        results.wzValue = wzValue;
-        results.cchValue = *pcchValue;
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+        results.cchValue = static_cast<DWORD>(*pcchValue);
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of GetVariableString args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzVariable);
+        ExitOnFailure(hr, "Failed to write variable name of GetVariableString args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of GetVariableString results.");
+
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.cchValue);
+        ExitOnFailure(hr, "Failed to write API version of GetVariableString results value.");
+
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_GETVARIABLESTRING, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA GetVariableString failed.");
+
+        // Read results.
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, &results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to read value length from GetVariableString results.");
 
-        hr = m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_GETVARIABLESTRING, &args, &results, m_pvBAEngineProcContext);
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, &results.cchValue);
+        ExitOnFailure(hr, "Failed to read value length from GetVariableString results.");
+
+        hr = BuffReadString(rpc.pbData, rpc.cbData, &iBuffer, &sczValue);
+        ExitOnFailure(hr, "Failed to read value from GetVariableString results.");
+
+        results.wzValue = sczValue;
+
+        if (wzValue)
+        {
+            hr = ::StringCchCopyW(wzValue, *pcchValue, results.wzValue);
+        }
+        else if (results.cchValue)
+        {
+            hr = E_MOREDATA;
+        }
 
         *pcchValue = results.cchValue;
+        ExitOnFailure(hr, "Failed to copy value from GetVariableString results.");
 
     LExit:
+        ReleaseStr(sczValue);
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
         return hr;
     }
 
@@ -140,21 +243,70 @@ public: // IBootstrapperEngine
         HRESULT hr = S_OK;
         BAENGINE_GETVARIABLEVERSION_ARGS args = { };
         BAENGINE_GETVARIABLEVERSION_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
+        SIZE_T iBuffer = 0;
+        LPWSTR sczValue = NULL;
 
         ExitOnNull(pcchValue, hr, E_INVALIDARG, "pcchValue is required");
 
-        args.cbSize = sizeof(args);
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
         args.wzVariable = wzVariable;
 
-        results.cbSize = sizeof(results);
-        results.wzValue = wzValue;
-        results.cchValue = *pcchValue;
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+        hr = DutilSizetToDword(*pcchValue, &results.cchValue);
+        ExitOnFailure(hr, "Failed to convert pcchValue to DWORD.");
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of GetVariableVersion args.");
 
-        hr = m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_GETVARIABLEVERSION, &args, &results, m_pvBAEngineProcContext);
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzVariable);
+        ExitOnFailure(hr, "Failed to write variable name of GetVariableVersion args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of GetVariableVersion results.");
+
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.cchValue);
+        ExitOnFailure(hr, "Failed to write API version of GetVariableVersion results value.");
+
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_GETVARIABLEVERSION, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA GetVariableVersion failed.");
+
+        // Read results.
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, &results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to read value length from GetVariableVersion results.");
+
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, &results.cchValue);
+        ExitOnFailure(hr, "Failed to read value length from GetVariableVersion results.");
+
+        hr = BuffReadString(rpc.pbData, rpc.cbData, &iBuffer, &sczValue);
+        ExitOnFailure(hr, "Failed to read value from GetVariableVersion results.");
+
+        results.wzValue = sczValue;
+
+        if (wzValue)
+        {
+            hr = ::StringCchCopyW(wzValue, *pcchValue, results.wzValue);
+        }
+        else if (results.cchValue)
+        {
+            hr = E_MOREDATA;
+        }
 
         *pcchValue = results.cchValue;
+        ExitOnFailure(hr, "Failed to copy value from GetVariableVersion results.");
 
     LExit:
+        ReleaseStr(sczValue);
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
         return hr;
     }
 
@@ -168,21 +320,74 @@ public: // IBootstrapperEngine
         HRESULT hr = S_OK;
         BAENGINE_GETRELATEDBUNDLEVARIABLE_ARGS args = { };
         BAENGINE_GETRELATEDBUNDLEVARIABLE_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
+        SIZE_T iBuffer = 0;
+        LPWSTR sczValue = NULL;
 
         ExitOnNull(pcchValue, hr, E_INVALIDARG, "pcchValue is required");
 
-        args.cbSize = sizeof(args);
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
         args.wzBundleId = wzBundleId;
         args.wzVariable = wzVariable;
 
-        results.cbSize = sizeof(results);
-        results.wzValue = wzValue;
-        results.cchValue = *pcchValue;
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+        hr = DutilSizetToDword(*pcchValue, &results.cchValue);
+        ExitOnFailure(hr, "Failed to convert pcchValue to DWORD.");
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of GetRelatedBundleVariable args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzBundleId);
+        ExitOnFailure(hr, "Failed to write bundle id of GetRelatedBundleVariable args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzVariable);
+        ExitOnFailure(hr, "Failed to write variable name of GetRelatedBundleVariable args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of GetRelatedBundleVariable results.");
+
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.cchValue);
+        ExitOnFailure(hr, "Failed to write API version of GetRelatedBundleVariable results value.");
 
-        hr = m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_GETRELATEDBUNDLEVARIABLE, &args, &results, m_pvBAEngineProcContext);
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_GETRELATEDBUNDLEVARIABLE, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA GetRelatedBundleVariable failed.");
+
+        // Read results.
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, &results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to read value length from GetRelatedBundleVariable results.");
+
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, &results.cchValue);
+        ExitOnFailure(hr, "Failed to read value length from GetRelatedBundleVariable results.");
+
+        hr = BuffReadString(rpc.pbData, rpc.cbData, &iBuffer, &sczValue);
+        ExitOnFailure(hr, "Failed to read value from GetRelatedBundleVariable results.");
+
+        results.wzValue = sczValue;
+
+        if (wzValue)
+        {
+            hr = ::StringCchCopyW(wzValue, *pcchValue, results.wzValue);
+        }
+        else if (results.cchValue)
+        {
+            hr = E_MOREDATA;
+        }
 
         *pcchValue = results.cchValue;
+        ExitOnFailure(hr, "Failed to copy value from GetRelatedBundleVariable results.");
+
     LExit:
+        ReleaseStr(sczValue);
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
         return hr;
     }
 
@@ -195,21 +400,70 @@ public: // IBootstrapperEngine
         HRESULT hr = S_OK;
         BAENGINE_FORMATSTRING_ARGS args = { };
         BAENGINE_FORMATSTRING_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
+        SIZE_T iBuffer = 0;
+        LPWSTR sczOut = NULL;
 
         ExitOnNull(pcchOut, hr, E_INVALIDARG, "pcchOut is required");
 
-        args.cbSize = sizeof(args);
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
         args.wzIn = wzIn;
 
-        results.cbSize = sizeof(results);
-        results.wzOut = wzOut;
-        results.cchOut = *pcchOut;
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+        hr = DutilSizetToDword(*pcchOut, &results.cchOut);
+        ExitOnFailure(hr, "Failed to convert pcchOut to DWORD.");
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of FormatString args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzIn);
+        ExitOnFailure(hr, "Failed to write string to format of FormatString args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of FormatString results.");
+
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.cchOut);
+        ExitOnFailure(hr, "Failed to write format string maximum size of FormatString results value.");
+
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_FORMATSTRING, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA FormatString failed.");
+
+        // Read results.
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, &results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to read size from FormatString results.");
+
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, &results.cchOut);
+        ExitOnFailure(hr, "Failed to read formatted string length from FormatString results.");
 
-        hr = m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_FORMATSTRING, &args, &results, m_pvBAEngineProcContext);
+        hr = BuffReadString(rpc.pbData, rpc.cbData, &iBuffer, &sczOut);
+        ExitOnFailure(hr, "Failed to read formatted string from FormatString results.");
+
+        results.wzOut = sczOut;
+
+        if (wzOut)
+        {
+            hr = ::StringCchCopyW(wzOut, *pcchOut, results.wzOut);
+        }
+        else if (results.cchOut)
+        {
+            hr = E_MOREDATA;
+        }
 
         *pcchOut = results.cchOut;
+        ExitOnFailure(hr, "Failed to copy formatted string from FormatString results.");
 
     LExit:
+        ReleaseStr(sczOut);
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
         return hr;
     }
 
@@ -222,21 +476,70 @@ public: // IBootstrapperEngine
         HRESULT hr = S_OK;
         BAENGINE_ESCAPESTRING_ARGS args = { };
         BAENGINE_ESCAPESTRING_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
+        SIZE_T iBuffer = 0;
+        LPWSTR sczOut = NULL;
 
         ExitOnNull(pcchOut, hr, E_INVALIDARG, "pcchOut is required");
 
-        args.cbSize = sizeof(args);
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
         args.wzIn = wzIn;
 
-        results.cbSize = sizeof(results);
-        results.wzOut = wzOut;
-        results.cchOut = *pcchOut;
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+        hr = DutilSizetToDword(*pcchOut, &results.cchOut);
+        ExitOnFailure(hr, "Failed to convert pcchOut to DWORD.");
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of EscapeString args.");
 
-        hr = m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_ESCAPESTRING, &args, &results, m_pvBAEngineProcContext);
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzIn);
+        ExitOnFailure(hr, "Failed to write string to escape of EscapeString args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of EscapeString results.");
+
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.cchOut);
+        ExitOnFailure(hr, "Failed to write escape string maximum size of EscapeString results value.");
+
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_ESCAPESTRING, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA EscapeString failed.");
+
+        // Read results.
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, &results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to read size from EscapeString results.");
+
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, &results.cchOut);
+        ExitOnFailure(hr, "Failed to read escaped string length from EscapeString results.");
+
+        hr = BuffReadString(rpc.pbData, rpc.cbData, &iBuffer, &sczOut);
+        ExitOnFailure(hr, "Failed to read escaped string from EscapeString results.");
+
+        results.wzOut = sczOut;
+
+        if (wzOut)
+        {
+            hr = ::StringCchCopyW(wzOut, *pcchOut, results.wzOut);
+        }
+        else if (results.cchOut)
+        {
+            hr = E_MOREDATA;
+        }
 
         *pcchOut = results.cchOut;
+        ExitOnFailure(hr, "Failed to copy escaped string from EscapeString results.");
 
     LExit:
+        ReleaseStr(sczOut);
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
         return hr;
     }
 
@@ -248,19 +551,56 @@ public: // IBootstrapperEngine
         HRESULT hr = S_OK;
         BAENGINE_EVALUATECONDITION_ARGS args = { };
         BAENGINE_EVALUATECONDITION_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
+        SIZE_T iBuffer = 0;
 
+        ExitOnNull(wzCondition, hr, E_INVALIDARG, "wzCondition is required");
         ExitOnNull(pf, hr, E_INVALIDARG, "pf is required");
 
-        args.cbSize = sizeof(args);
+        // Empty condition evaluates to true.
+        if (!*wzCondition)
+        {
+            *pf = TRUE;
+            ExitFunction();
+        }
+
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
         args.wzCondition = wzCondition;
 
-        results.cbSize = sizeof(results);
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of EvaluateCondition args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzCondition);
+        ExitOnFailure(hr, "Failed to write condition of EvaluateCondition args.");
 
-        hr = m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_EVALUATECONDITION, &args, &results, m_pvBAEngineProcContext);
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of EvaluateCondition results.");
+
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_EVALUATECONDITION, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA EvaluateCondition failed.");
+
+        // Read results.
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, &results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to read size from EvaluateCondition results.");
+
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, reinterpret_cast<DWORD*>(&results.f));
+        ExitOnFailure(hr, "Failed to read result from EvaluateCondition results.");
 
         *pf = results.f;
 
     LExit:
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
         return hr;
     }
 
@@ -269,16 +609,44 @@ public: // IBootstrapperEngine
         __in_z LPCWSTR wzMessage
         )
     {
+        HRESULT hr = S_OK;
         BAENGINE_LOG_ARGS args = { };
         BAENGINE_LOG_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
 
-        args.cbSize = sizeof(args);
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
         args.level = level;
         args.wzMessage = wzMessage;
 
-        results.cbSize = sizeof(results);
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of Log args.");
+
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.level);
+        ExitOnFailure(hr, "Failed to write level of Log args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzMessage);
+        ExitOnFailure(hr, "Failed to write message of Log args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of Log results.");
 
-        return m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_LOG, &args, &results, m_pvBAEngineProcContext);
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_LOG, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA Log failed.");
+
+    LExit:
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
+        return hr;
     }
 
     virtual STDMETHODIMP SendEmbeddedError(
@@ -291,21 +659,56 @@ public: // IBootstrapperEngine
         HRESULT hr = S_OK;
         BAENGINE_SENDEMBEDDEDERROR_ARGS args = { };
         BAENGINE_SENDEMBEDDEDERROR_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
+        SIZE_T iBuffer = 0;
 
         ExitOnNull(pnResult, hr, E_INVALIDARG, "pnResult is required");
 
-        args.cbSize = sizeof(args);
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
         args.dwErrorCode = dwErrorCode;
         args.wzMessage = wzMessage;
         args.dwUIHint = dwUIHint;
 
-        results.cbSize = sizeof(results);
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of SendEmbeddedError args.");
+
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwErrorCode);
+        ExitOnFailure(hr, "Failed to write error code of SendEmbeddedError args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzMessage);
+        ExitOnFailure(hr, "Failed to write message of SendEmbeddedError args.");
+
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwUIHint);
+        ExitOnFailure(hr, "Failed to write UI hint of SendEmbeddedError args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of SendEmbeddedError results.");
 
-        hr = m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_SENDEMBEDDEDERROR, &args, &results, m_pvBAEngineProcContext);
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_SENDEMBEDDEDERROR, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA SendEmbeddedError failed.");
+
+        // Read results.
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, &results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to read size from SendEmbeddedError results.");
+
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, reinterpret_cast<DWORD*>(&results.nResult));
+        ExitOnFailure(hr, "Failed to read result from SendEmbeddedError results.");
 
         *pnResult = results.nResult;
 
     LExit:
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
         return hr;
     }
 
@@ -318,20 +721,52 @@ public: // IBootstrapperEngine
         HRESULT hr = S_OK;
         BAENGINE_SENDEMBEDDEDPROGRESS_ARGS args = { };
         BAENGINE_SENDEMBEDDEDPROGRESS_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
+        SIZE_T iBuffer = 0;
 
         ExitOnNull(pnResult, hr, E_INVALIDARG, "pnResult is required");
 
-        args.cbSize = sizeof(args);
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
         args.dwProgressPercentage = dwProgressPercentage;
         args.dwOverallProgressPercentage = dwOverallProgressPercentage;
 
-        results.cbSize = sizeof(results);
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of SendEmbeddedProgress args.");
+
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwProgressPercentage);
+        ExitOnFailure(hr, "Failed to write progress of SendEmbeddedProgress args.");
+
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwOverallProgressPercentage);
+        ExitOnFailure(hr, "Failed to write overall progress of SendEmbeddedProgress args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of SendEmbeddedProgress results.");
+
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_SENDEMBEDDEDPROGRESS, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA SendEmbeddedProgress failed.");
+
+        // Read results.
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, &results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to read size from SendEmbeddedProgress results.");
 
-        hr = m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_SENDEMBEDDEDPROGRESS, &args, &results, m_pvBAEngineProcContext);
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, reinterpret_cast<DWORD*>(&results.nResult));
+        ExitOnFailure(hr, "Failed to read result from SendEmbeddedProgress results.");
 
         *pnResult = results.nResult;
 
     LExit:
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
         return hr;
     }
 
@@ -340,22 +775,67 @@ public: // IBootstrapperEngine
         __in_z_opt LPCWSTR wzDownloadSource,
         __in DWORD64 qwSize,
         __in BOOTSTRAPPER_UPDATE_HASH_TYPE hashType,
-        __in_z_opt LPCWSTR wzHash
+        __in_z_opt LPCWSTR wzHash,
+        __in_z_opt LPCWSTR wzUpdatePackageId
         )
     {
+        HRESULT hr = S_OK;
         BAENGINE_SETUPDATE_ARGS args = { };
         BAENGINE_SETUPDATE_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
 
-        args.cbSize = sizeof(args);
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
         args.wzLocalSource = wzLocalSource;
         args.wzDownloadSource = wzDownloadSource;
         args.qwSize = qwSize;
         args.hashType = hashType;
         args.wzHash = wzHash;
+        args.wzUpdatePackageId = wzUpdatePackageId;
+
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of SetUpdate args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzLocalSource);
+        ExitOnFailure(hr, "Failed to write local source of SetUpdate args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzDownloadSource);
+        ExitOnFailure(hr, "Failed to write download source of SetUpdate args.");
+
+        hr = BuffWriteNumber64ToBuffer(&bufferArgs, args.qwSize);
+        ExitOnFailure(hr, "Failed to write udpate size of SetUpdate args.");
+
+        hr = BuffWriteNumberToBuffer(&bufferArgs, static_cast<DWORD>(args.hashType));
+        ExitOnFailure(hr, "Failed to write hash type of SetUpdate args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzHash);
+        ExitOnFailure(hr, "Failed to write hash of SetUpdate args.");
 
-        results.cbSize = sizeof(results);
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzHash);
+        ExitOnFailure(hr, "Failed to write hash of SetUpdate args.");
 
-        return m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_SETUPDATE, &args, &results, m_pvBAEngineProcContext);
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzUpdatePackageId);
+        ExitOnFailure(hr, "Failed to write update package id to SetUpdate args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of SetUpdate results.");
+
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_SETUPDATE, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA SetUpdate failed.");
+
+    LExit:
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
+        return hr;
     }
 
     virtual STDMETHODIMP SetLocalSource(
@@ -364,17 +844,48 @@ public: // IBootstrapperEngine
         __in_z LPCWSTR wzPath
         )
     {
+        HRESULT hr = S_OK;
         BAENGINE_SETLOCALSOURCE_ARGS args = { };
         BAENGINE_SETLOCALSOURCE_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
 
-        args.cbSize = sizeof(args);
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
         args.wzPackageOrContainerId = wzPackageOrContainerId;
         args.wzPayloadId = wzPayloadId;
         args.wzPath = wzPath;
 
-        results.cbSize = sizeof(results);
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of SetLocalSource args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzPackageOrContainerId);
+        ExitOnFailure(hr, "Failed to write package or container id of SetLocalSource args.");
 
-        return m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_SETLOCALSOURCE, &args, &results, m_pvBAEngineProcContext);
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzPayloadId);
+        ExitOnFailure(hr, "Failed to write payload id of SetLocalSource args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzPath);
+        ExitOnFailure(hr, "Failed to write path of SetLocalSource args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of SetLocalSource results.");
+
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_SETLOCALSOURCE, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA SetLocalSource failed.");
+
+    LExit:
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
+        return hr;
     }
 
     virtual STDMETHODIMP SetDownloadSource(
@@ -382,22 +893,64 @@ public: // IBootstrapperEngine
         __in_z_opt LPCWSTR wzPayloadId,
         __in_z LPCWSTR wzUrl,
         __in_z_opt LPCWSTR wzUser,
-        __in_z_opt LPCWSTR wzPassword
+        __in_z_opt LPCWSTR wzPassword,
+        __in_z_opt LPCWSTR wzAuthorizationHeader
         )
     {
+        HRESULT hr = S_OK;
         BAENGINE_SETDOWNLOADSOURCE_ARGS args = { };
         BAENGINE_SETDOWNLOADSOURCE_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
 
-        args.cbSize = sizeof(args);
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
         args.wzPackageOrContainerId = wzPackageOrContainerId;
         args.wzPayloadId = wzPayloadId;
         args.wzUrl = wzUrl;
         args.wzUser = wzUser;
         args.wzPassword = wzPassword;
+        args.wzAuthorizationHeader = wzAuthorizationHeader;
 
-        results.cbSize = sizeof(results);
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
 
-        return m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_SETDOWNLOADSOURCE, &args, &results, m_pvBAEngineProcContext);
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of SetDownloadSource args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzPackageOrContainerId);
+        ExitOnFailure(hr, "Failed to write package or container id of SetDownloadSource args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzPayloadId);
+        ExitOnFailure(hr, "Failed to write payload id of SetDownloadSource args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzUrl);
+        ExitOnFailure(hr, "Failed to write url of SetDownloadSource args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzUser);
+        ExitOnFailure(hr, "Failed to write user of SetDownloadSource args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzPassword);
+        ExitOnFailure(hr, "Failed to write password of SetDownloadSource args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzAuthorizationHeader);
+        ExitOnFailure(hr, "Failed to write authorization header of SetDownloadSource args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of SetDownloadSource results.");
+
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_SETDOWNLOADSOURCE, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA SetDownloadSource failed.");
+
+    LExit:
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
+        return hr;
     }
 
     virtual STDMETHODIMP SetVariableNumeric(
@@ -405,16 +958,44 @@ public: // IBootstrapperEngine
         __in LONGLONG llValue
         )
     {
+        HRESULT hr = S_OK;
         BAENGINE_SETVARIABLENUMERIC_ARGS args = { };
         BAENGINE_SETVARIABLENUMERIC_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
 
-        args.cbSize = sizeof(args);
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
         args.wzVariable = wzVariable;
         args.llValue = llValue;
 
-        results.cbSize = sizeof(results);
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of SetVariableNumeric args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzVariable);
+        ExitOnFailure(hr, "Failed to write variable of SetVariableNumeric args.");
+
+        hr = BuffWriteNumber64ToBuffer(&bufferArgs, static_cast<DWORD64>(args.llValue));
+        ExitOnFailure(hr, "Failed to write value of SetVariableNumeric args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of SetVariableNumeric results.");
+
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_SETVARIABLENUMERIC, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA SetVariableNumeric failed.");
 
-        return m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_SETVARIABLENUMERIC, &args, &results, m_pvBAEngineProcContext);
+    LExit:
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
+        return hr;
     }
 
     virtual STDMETHODIMP SetVariableString(
@@ -423,17 +1004,48 @@ public: // IBootstrapperEngine
         __in BOOL fFormatted
         )
     {
+        HRESULT hr = S_OK;
         BAENGINE_SETVARIABLESTRING_ARGS args = { };
         BAENGINE_SETVARIABLESTRING_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
 
-        args.cbSize = sizeof(args);
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
         args.wzVariable = wzVariable;
         args.wzValue = wzValue;
         args.fFormatted = fFormatted;
 
-        results.cbSize = sizeof(results);
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of SetVariableString args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzVariable);
+        ExitOnFailure(hr, "Failed to write variable of SetVariableString args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzValue);
+        ExitOnFailure(hr, "Failed to write value of SetVariableString args.");
+
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.fFormatted);
+        ExitOnFailure(hr, "Failed to write formatted flag of SetVariableString args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of SetVariableString results.");
 
-        return m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_SETVARIABLESTRING, &args, &results, m_pvBAEngineProcContext);
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_SETVARIABLESTRING, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA SetVariableString failed.");
+
+    LExit:
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
+        return hr;
     }
 
     virtual STDMETHODIMP SetVariableVersion(
@@ -441,103 +1053,278 @@ public: // IBootstrapperEngine
         __in_z_opt LPCWSTR wzValue
         )
     {
+        HRESULT hr = S_OK;
         BAENGINE_SETVARIABLEVERSION_ARGS args = { };
         BAENGINE_SETVARIABLEVERSION_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
 
-        args.cbSize = sizeof(args);
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
         args.wzVariable = wzVariable;
         args.wzValue = wzValue;
 
-        results.cbSize = sizeof(results);
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of SetVariableVersion args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzVariable);
+        ExitOnFailure(hr, "Failed to write variable of SetVariableVersion args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzValue);
+        ExitOnFailure(hr, "Failed to write value of SetVariableVersion args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of SetVariableVersion results.");
 
-        return m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_SETVARIABLEVERSION, &args, &results, m_pvBAEngineProcContext);
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_SETVARIABLEVERSION, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA SetVariableVersion failed.");
+
+    LExit:
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
+        return hr;
     }
 
     virtual STDMETHODIMP CloseSplashScreen()
     {
+        HRESULT hr = S_OK;
         BAENGINE_CLOSESPLASHSCREEN_ARGS args = { };
         BAENGINE_CLOSESPLASHSCREEN_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
+
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of CloseSplashScreen args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of CloseSplashScreen results.");
 
-        args.cbSize = sizeof(args);
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_CLOSESPLASHSCREEN, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA CloseSplashScreen failed.");
 
-        results.cbSize = sizeof(results);
+    LExit:
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
 
-        return m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_CLOSESPLASHSCREEN, &args, &results, m_pvBAEngineProcContext);
+        return hr;
     }
 
     virtual STDMETHODIMP Detect(
         __in_opt HWND hwndParent
         )
     {
+        HRESULT hr = S_OK;
         BAENGINE_DETECT_ARGS args = { };
         BAENGINE_DETECT_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
+
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+        args.hwndParent = reinterpret_cast<DWORD64>(hwndParent);
+
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
 
-        args.cbSize = sizeof(args);
-        args.hwndParent = hwndParent;
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of Detect args.");
 
-        results.cbSize = sizeof(results);
+        hr = BuffWriteNumber64ToBuffer(&bufferArgs, args.hwndParent);
+        ExitOnFailure(hr, "Failed to write parent window of Detect args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of Detect results.");
+
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_DETECT, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA Detect failed.");
+
+    LExit:
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
 
-        return m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_DETECT, &args, &results, m_pvBAEngineProcContext);
+        return hr;
     }
 
     virtual STDMETHODIMP Plan(
         __in BOOTSTRAPPER_ACTION action
         )
     {
+        HRESULT hr = S_OK;
         BAENGINE_PLAN_ARGS args = { };
         BAENGINE_PLAN_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
 
-        args.cbSize = sizeof(args);
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
         args.action = action;
 
-        results.cbSize = sizeof(results);
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of Plan args.");
+
+        hr = BuffWriteNumberToBuffer(&bufferArgs, static_cast<DWORD>(args.action));
+        ExitOnFailure(hr, "Failed to write parent window of Plan args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of Plan results.");
 
-        return m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_PLAN, &args, &results, m_pvBAEngineProcContext);
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_PLAN, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA Plan failed.");
+
+    LExit:
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
+        return hr;
     }
 
     virtual STDMETHODIMP Elevate(
         __in_opt HWND hwndParent
         )
     {
+        HRESULT hr = S_OK;
         BAENGINE_ELEVATE_ARGS args = { };
         BAENGINE_ELEVATE_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
+
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+        args.hwndParent = reinterpret_cast<DWORD64>(hwndParent);
+
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of Elevate args.");
 
-        args.cbSize = sizeof(args);
-        args.hwndParent = hwndParent;
+        hr = BuffWriteNumber64ToBuffer(&bufferArgs, args.hwndParent);
+        ExitOnFailure(hr, "Failed to write parent window of Elevate args.");
 
-        results.cbSize = sizeof(results);
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of Elevate results.");
 
-        return m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_ELEVATE, &args, &results, m_pvBAEngineProcContext);
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_ELEVATE, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA Elevate failed.");
+
+    LExit:
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
+        return hr;
     }
 
     virtual STDMETHODIMP Apply(
         __in HWND hwndParent
         )
     {
+        HRESULT hr = S_OK;
         BAENGINE_APPLY_ARGS args = { };
         BAENGINE_APPLY_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
+
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+        args.hwndParent = reinterpret_cast<DWORD64>(hwndParent);
+
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of Apply args.");
+
+        hr = BuffWriteNumber64ToBuffer(&bufferArgs, args.hwndParent);
+        ExitOnFailure(hr, "Failed to write parent window of Apply args.");
 
-        args.cbSize = sizeof(args);
-        args.hwndParent = hwndParent;
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of Apply results.");
 
-        results.cbSize = sizeof(results);
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_APPLY, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA Apply failed.");
 
-        return m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_APPLY, &args, &results, m_pvBAEngineProcContext);
+    LExit:
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
+        return hr;
     }
 
     virtual STDMETHODIMP Quit(
         __in DWORD dwExitCode
         )
     {
+        HRESULT hr = S_OK;
         BAENGINE_QUIT_ARGS args = { };
         BAENGINE_QUIT_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
 
-        args.cbSize = sizeof(args);
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
         args.dwExitCode = dwExitCode;
 
-        results.cbSize = sizeof(results);
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
 
-        return m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_QUIT, &args, &results, m_pvBAEngineProcContext);
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of Quit args.");
+
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwExitCode);
+        ExitOnFailure(hr, "Failed to write exit code of Quit args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of Quit results.");
+
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_QUIT, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA Quit failed.");
+
+    LExit:
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
+        return hr;
     }
 
     virtual STDMETHODIMP LaunchApprovedExe(
@@ -547,33 +1334,101 @@ public: // IBootstrapperEngine
         __in DWORD dwWaitForInputIdleTimeout
         )
     {
+        HRESULT hr = S_OK;
         BAENGINE_LAUNCHAPPROVEDEXE_ARGS args = { };
         BAENGINE_LAUNCHAPPROVEDEXE_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
+
+        ExitOnNull(wzApprovedExeForElevationId, hr, E_INVALIDARG, "wzApprovedExeForElevationId is required");
 
-        args.cbSize = sizeof(args);
-        args.hwndParent = hwndParent;
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+        args.hwndParent = reinterpret_cast<DWORD64>(hwndParent);
         args.wzApprovedExeForElevationId = wzApprovedExeForElevationId;
         args.wzArguments = wzArguments;
         args.dwWaitForInputIdleTimeout = dwWaitForInputIdleTimeout;
 
-        results.cbSize = sizeof(results);
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
 
-        return m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_LAUNCHAPPROVEDEXE, &args, &results, m_pvBAEngineProcContext);
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of LaunchApprovedExe args.");
+
+        hr = BuffWriteNumber64ToBuffer(&bufferArgs, args.hwndParent);
+        ExitOnFailure(hr, "Failed to write parent window of LaunchApprovedExe args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzApprovedExeForElevationId);
+        ExitOnFailure(hr, "Failed to write approved exe elevation id of LaunchApprovedExe args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzArguments);
+        ExitOnFailure(hr, "Failed to write arguments of LaunchApprovedExe args.");
+
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwWaitForInputIdleTimeout);
+        ExitOnFailure(hr, "Failed to write wait for idle input timeout of LaunchApprovedExe args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of LaunchApprovedExe results.");
+
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_LAUNCHAPPROVEDEXE, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA LaunchApprovedExe failed.");
+
+    LExit:
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
+        return hr;
     }
 
     virtual STDMETHODIMP SetUpdateSource(
-        __in_z LPCWSTR wzUrl
+        __in_z LPCWSTR wzUrl,
+        __in_z_opt LPCWSTR wzAuthorizationHeader
         )
     {
+        HRESULT hr = S_OK;
         BAENGINE_SETUPDATESOURCE_ARGS args = { };
         BAENGINE_SETUPDATESOURCE_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
+
+        ExitOnNull(wzUrl, hr, E_INVALIDARG, "wzUrl is required");
 
-        args.cbSize = sizeof(args);
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
         args.wzUrl = wzUrl;
+        args.wzAuthorizationHeader = wzAuthorizationHeader;
+
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of SetUpdateSource args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzUrl);
+        ExitOnFailure(hr, "Failed to write url of SetUpdateSource args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzAuthorizationHeader);
+        ExitOnFailure(hr, "Failed to write authorization header of SetUpdateSource args.");
 
-        results.cbSize = sizeof(results);
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of SetUpdateSource results.");
 
-        return m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_SETUPDATESOURCE, &args, &results, m_pvBAEngineProcContext);
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_SETUPDATESOURCE, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA SetUpdateSource failed.");
+
+    LExit:
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
+        return hr;
     }
 
     virtual STDMETHODIMP CompareVersions(
@@ -585,66 +1440,133 @@ public: // IBootstrapperEngine
         HRESULT hr = S_OK;
         BAENGINE_COMPAREVERSIONS_ARGS args = { };
         BAENGINE_COMPAREVERSIONS_RESULTS results = { };
+        BUFF_BUFFER bufferArgs = { };
+        BUFF_BUFFER bufferResults = { };
+        PIPE_RPC_RESULT rpc = { };
+        SIZE_T iBuffer = 0;
 
         ExitOnNull(pnResult, hr, E_INVALIDARG, "pnResult is required");
 
-        args.cbSize = sizeof(args);
+        // Init send structs.
+        args.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
         args.wzVersion1 = wzVersion1;
         args.wzVersion2 = wzVersion2;
 
-        results.cbSize = sizeof(results);
+        results.dwApiVersion = WIX_5_BOOTSTRAPPER_APPLICATION_API_VERSION;
+
+        // Send args.
+        hr = BuffWriteNumberToBuffer(&bufferArgs, args.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of CompareVersions args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzVersion1);
+        ExitOnFailure(hr, "Failed to write first input of CompareVersions args.");
+
+        hr = BuffWriteStringToBuffer(&bufferArgs, args.wzVersion2);
+        ExitOnFailure(hr, "Failed to write second input of CompareVersions args.");
+
+        // Send results.
+        hr = BuffWriteNumberToBuffer(&bufferResults, results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to write API version of CompareVersions results.");
+
+        // Get results.
+        hr = SendRequest(BOOTSTRAPPER_ENGINE_MESSAGE_COMPAREVERSIONS, &bufferArgs, &bufferResults, &rpc);
+        ExitOnFailure(hr, "BA CompareVersions failed.");
 
-        hr = m_pfnBAEngineProc(BOOTSTRAPPER_ENGINE_MESSAGE_COMPAREVERSIONS, &args, &results, m_pvBAEngineProcContext);
+        // Read results.
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, &results.dwApiVersion);
+        ExitOnFailure(hr, "Failed to read size from CompareVersions results.");
+
+        hr = BuffReadNumber(rpc.pbData, rpc.cbData, &iBuffer, reinterpret_cast<DWORD*>(&results.nResult));
+        ExitOnFailure(hr, "Failed to read result from CompareVersions results.");
 
         *pnResult = results.nResult;
 
     LExit:
+        PipeFreeRpcResult(&rpc);
+        ReleaseBuffer(bufferResults);
+        ReleaseBuffer(bufferArgs);
+
         return hr;
     }
 
-public:
-    HRESULT Init()
+private:
+    HRESULT SendRequest(
+        __in DWORD dwMessageType,
+        __in BUFF_BUFFER* pBufferArgs,
+        __in BUFF_BUFFER* pBufferResults,
+        __in PIPE_RPC_RESULT* pRpc
+        )
     {
-        return ::CoCreateFreeThreadedMarshaler(this, &m_pFreeThreadedMarshaler);
+        HRESULT hr = S_OK;
+        BUFF_BUFFER buffer = { };
+
+        hr = CombineArgsAndResults(pBufferArgs, pBufferResults, &buffer);
+        if (SUCCEEDED(hr))
+        {
+            hr = PipeRpcRequest(&m_hRpcPipe, dwMessageType, buffer.pbData, buffer.cbData, pRpc);
+        }
+
+        ReleaseBuffer(buffer);
+        return hr;
     }
 
+    HRESULT CombineArgsAndResults(
+        __in BUFF_BUFFER* pBufferArgs,
+        __in BUFF_BUFFER* pBufferResults,
+        __in BUFF_BUFFER* pBufferCombined
+        )
+    {
+        HRESULT hr = S_OK;
+
+        // Write args to buffer.
+        hr = BuffWriteStreamToBuffer(pBufferCombined, pBufferArgs->pbData, pBufferArgs->cbData);
+        ExitOnFailure(hr, "Failed to write args buffer.");
+
+        // Write results to buffer.
+        hr = BuffWriteStreamToBuffer(pBufferCombined, pBufferResults->pbData, pBufferResults->cbData);
+        ExitOnFailure(hr, "Failed to write results buffer.");
+
+    LExit:
+        return hr;
+    }
+
+public:
     CBalBootstrapperEngine(
-        __in PFN_BOOTSTRAPPER_ENGINE_PROC pfnBAEngineProc,
-        __in_opt LPVOID pvBAEngineProcContext
+        __in HANDLE hPipe,
+        __out HRESULT* phr
         )
     {
         m_cReferences = 1;
-        m_pfnBAEngineProc = pfnBAEngineProc;
-        m_pvBAEngineProcContext = pvBAEngineProcContext;
-        m_pFreeThreadedMarshaler = NULL;
+
+        PipeRpcInitialize(&m_hRpcPipe, hPipe, FALSE);
+
+        *phr = ::CoCreateFreeThreadedMarshaler(this, &m_pFreeThreadedMarshaler);
     }
 
     ~CBalBootstrapperEngine()
     {
+        PipeRpcUninitiailize(&m_hRpcPipe);
         ReleaseObject(m_pFreeThreadedMarshaler);
     }
 
 private:
     long m_cReferences;
-    PFN_BOOTSTRAPPER_ENGINE_PROC m_pfnBAEngineProc;
-    LPVOID m_pvBAEngineProcContext;
+    PIPE_RPC_HANDLE m_hRpcPipe;
     IUnknown* m_pFreeThreadedMarshaler;
 };
 
+
 HRESULT BalBootstrapperEngineCreate(
-    __in PFN_BOOTSTRAPPER_ENGINE_PROC pfnBAEngineProc,
-    __in_opt LPVOID pvBAEngineProcContext,
+    __in HANDLE hPipe,
     __out IBootstrapperEngine** ppBootstrapperEngine
     )
 {
     HRESULT hr = S_OK;
     CBalBootstrapperEngine* pBootstrapperEngine = NULL;
 
-    pBootstrapperEngine = new CBalBootstrapperEngine(pfnBAEngineProc, pvBAEngineProcContext);
+    pBootstrapperEngine = new CBalBootstrapperEngine(hPipe, &hr);
     ExitOnNull(pBootstrapperEngine, hr, E_OUTOFMEMORY, "Failed to allocate new BalBootstrapperEngine object.");
-
-    hr = pBootstrapperEngine->Init();
-    ExitOnFailure(hr, "Failed to initialize CBalBootstrapperEngine.");
+    ExitOnFailure(hr, "Failed to initialize BalBootstrapperEngine.");
 
     hr = pBootstrapperEngine->QueryInterface(IID_PPV_ARGS(ppBootstrapperEngine));
     ExitOnFailure(hr, "Failed to QI for IBootstrapperEngine from BalBootstrapperEngine object.");