Consolidate the code for the BA and bext engines.

1 files changed, 26 insertions, 502 deletions

diff --git a/src/engine/EngineForApplication.cpp b/src/engine/EngineForApplication.cpp
index e3ce7670..361e0f4e 100644
--- a/src/engine/EngineForApplication.cpp
+++ b/src/engine/EngineForApplication.cpp
@@ -3,12 +3,6 @@
 #include "precomp.h"
 
 
-static HRESULT CopyStringToBA(
-    __in LPWSTR wzValue,
-    __in_opt LPWSTR wzBuffer,
-    __inout DWORD* pcchBuffer
-    );
-
 static HRESULT BAEngineGetPackageCount(
     __in BOOTSTRAPPER_ENGINE_CONTEXT* pContext,
     __in const LPVOID pvArgs,
@@ -18,9 +12,8 @@ static HRESULT BAEngineGetPackageCount(
     HRESULT hr = S_OK;
     ValidateMessageArgs(hr, pvArgs, BAENGINE_GETPACKAGECOUNT_ARGS, pArgs);
     ValidateMessageResults(hr, pvResults, BAENGINE_GETPACKAGECOUNT_RESULTS, pResults);
-    DWORD* pcPackages = &pResults->cPackages;
 
-    *pcPackages = pContext->pEngineState->packages.cPackages;
+    ExternalEngineGetPackageCount(pContext->pEngineState, &pResults->cPackages);
 
 LExit:
     return hr;
@@ -35,17 +28,8 @@ static HRESULT BAEngineGetVariableNumeric(
     HRESULT hr = S_OK;
     ValidateMessageArgs(hr, pvArgs, BAENGINE_GETVARIABLENUMERIC_ARGS, pArgs);
     ValidateMessageResults(hr, pvResults, BAENGINE_GETVARIABLENUMERIC_RESULTS, pResults);
-    LPCWSTR wzVariable = pArgs->wzVariable;
-    LONGLONG* pllValue = &pResults->llValue;
 
-    if (wzVariable && *wzVariable)
-    {
-        hr = VariableGetNumeric(&pContext->pEngineState->variables, wzVariable, pllValue);
-    }
-    else
-    {
-        hr = E_INVALIDARG;
-    }
+    hr = ExternalEngineGetVariableNumeric(pContext->pEngineState, pArgs->wzVariable, &pResults->llValue);
 
 LExit:
     return hr;
@@ -58,28 +42,12 @@ static HRESULT BAEngineGetVariableString(
     )
 {
     HRESULT hr = S_OK;
-    LPWSTR sczValue = NULL;
     ValidateMessageArgs(hr, pvArgs, BAENGINE_GETVARIABLESTRING_ARGS, pArgs);
     ValidateMessageResults(hr, pvResults, BAENGINE_GETVARIABLESTRING_RESULTS, pResults);
-    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))
-        {
-            hr = CopyStringToBA(sczValue, wzValue, pcchValue);
-        }
-    }
-    else
-    {
-        hr = E_INVALIDARG;
-    }
+    hr = ExternalEngineGetVariableString(pContext->pEngineState, pArgs->wzVariable, pResults->wzValue, &pResults->cchValue);
 
 LExit:
-    StrSecureZeroFreeString(sczValue);
     return hr;
 }
 
@@ -90,29 +58,12 @@ static HRESULT BAEngineGetVariableVersion(
     )
 {
     HRESULT hr = S_OK;
-    VERUTIL_VERSION* pVersion = NULL;
     ValidateMessageArgs(hr, pvArgs, BAENGINE_GETVARIABLEVERSION_ARGS, pArgs);
     ValidateMessageResults(hr, pvResults, BAENGINE_GETVARIABLEVERSION_RESULTS, pResults);
-    LPCWSTR wzVariable = pArgs->wzVariable;
-    LPWSTR wzValue = pResults->wzValue;
-    DWORD* pcchValue = &pResults->cchValue;
 
-    if (wzVariable && *wzVariable)
-    {
-        hr = VariableGetVersion(&pContext->pEngineState->variables, wzVariable, &pVersion);
-        if (SUCCEEDED(hr))
-        {
-            hr = CopyStringToBA(pVersion->sczVersion, wzValue, pcchValue);
-        }
-    }
-    else
-    {
-        hr = E_INVALIDARG;
-    }
+    hr = ExternalEngineGetVariableVersion(pContext->pEngineState, pArgs->wzVariable, pResults->wzValue, &pResults->cchValue);
 
 LExit:
-    ReleaseVerutilVersion(pVersion);
-
     return hr;
 }
 
@@ -123,28 +74,12 @@ static HRESULT BAEngineFormatString(
     )
 {
     HRESULT hr = S_OK;
-    LPWSTR sczValue = NULL;
     ValidateMessageArgs(hr, pvArgs, BAENGINE_FORMATSTRING_ARGS, pArgs);
     ValidateMessageResults(hr, pvResults, BAENGINE_FORMATSTRING_RESULTS, pResults);
-    LPCWSTR wzIn = pArgs->wzIn;
-    LPWSTR wzOut = pResults->wzOut;
-    DWORD* pcchOut = &pResults->cchOut;
 
-    if (wzIn && *wzIn)
-    {
-        hr = VariableFormatString(&pContext->pEngineState->variables, wzIn, &sczValue, NULL);
-        if (SUCCEEDED(hr))
-        {
-            hr = CopyStringToBA(sczValue, wzOut, pcchOut);
-        }
-    }
-    else
-    {
-        hr = E_INVALIDARG;
-    }
+    hr = ExternalEngineFormatString(pContext->pEngineState, pArgs->wzIn, pResults->wzOut, &pResults->cchOut);
 
 LExit:
-    StrSecureZeroFreeString(sczValue);
     return hr;
 }
 
@@ -155,28 +90,12 @@ static HRESULT BAEngineEscapeString(
     )
 {
     HRESULT hr = S_OK;
-    LPWSTR sczValue = NULL;
     ValidateMessageArgs(hr, pvArgs, BAENGINE_ESCAPESTRING_ARGS, pArgs);
     ValidateMessageResults(hr, pvResults, BAENGINE_ESCAPESTRING_RESULTS, pResults);
-    LPCWSTR wzIn = pArgs->wzIn;
-    LPWSTR wzOut = pResults->wzOut;
-    DWORD* pcchOut = &pResults->cchOut;
 
-    if (wzIn && *wzIn)
-    {
-        hr = VariableEscapeString(wzIn, &sczValue);
-        if (SUCCEEDED(hr))
-        {
-            hr = CopyStringToBA(sczValue, wzOut, pcchOut);
-        }
-    }
-    else
-    {
-        hr = E_INVALIDARG;
-    }
+    hr = ExternalEngineEscapeString(pArgs->wzIn, pResults->wzOut, &pResults->cchOut);
 
 LExit:
-    StrSecureZeroFreeString(sczValue);
     return hr;
 }
 
@@ -189,17 +108,8 @@ static HRESULT BAEngineEvaluateCondition(
     HRESULT hr = S_OK;
     ValidateMessageArgs(hr, pvArgs, BAENGINE_EVALUATECONDITION_ARGS, pArgs);
     ValidateMessageResults(hr, pvResults, BAENGINE_EVALUATECONDITION_RESULTS, pResults);
-    LPCWSTR wzCondition = pArgs->wzCondition;
-    BOOL* pf = &pResults->f;
 
-    if (wzCondition && *wzCondition)
-    {
-        hr = ConditionEvaluate(&pContext->pEngineState->variables, wzCondition, pf);
-    }
-    else
-    {
-        hr = E_INVALIDARG;
-    }
+    hr = ExternalEngineEvaluateCondition(pContext->pEngineState, pArgs->wzCondition, &pResults->f);
 
 LExit:
     return hr;
@@ -212,13 +122,11 @@ static HRESULT BAEngineLog(
     )
 {
     HRESULT hr = S_OK;
+    REPORT_LEVEL rl = REPORT_NONE;
     ValidateMessageArgs(hr, pvArgs, BAENGINE_LOG_ARGS, pArgs);
     ValidateMessageResults(hr, pvResults, BAENGINE_LOG_RESULTS, pResults);
-    REPORT_LEVEL rl = REPORT_NONE;
-    BOOTSTRAPPER_LOG_LEVEL level = pArgs->level;
-    LPCWSTR wzMessage = pArgs->wzMessage;
 
-    switch (level)
+    switch (pArgs->level)
     {
     case BOOTSTRAPPER_LOG_LEVEL_STANDARD:
         rl = REPORT_STANDARD;
@@ -240,7 +148,7 @@ static HRESULT BAEngineLog(
         ExitFunction1(hr = E_INVALIDARG);
     }
 
-    hr = LogStringLine(rl, "%ls", wzMessage);
+    hr = ExternalEngineLog(rl, pArgs->wzMessage);
     ExitOnFailure(hr, "Failed to log BA message.");
 
 LExit:
@@ -254,38 +162,12 @@ static HRESULT BAEngineSendEmbeddedError(
     )
 {
     HRESULT hr = S_OK;
-    BYTE* pbData = NULL;
-    DWORD cbData = 0;
-    DWORD dwResult = 0;
     ValidateMessageArgs(hr, pvArgs, BAENGINE_SENDEMBEDDEDERROR_ARGS, pArgs);
     ValidateMessageResults(hr, pvResults, BAENGINE_SENDEMBEDDEDERROR_RESULTS, pResults);
-    DWORD dwErrorCode = pArgs->dwErrorCode;
-    LPCWSTR wzMessage = pArgs->wzMessage;
-    DWORD dwUIHint = pArgs->dwUIHint;
-    int* pnResult = &pResults->nResult;
-
-    if (BURN_MODE_EMBEDDED != pContext->pEngineState->mode)
-    {
-        hr = HRESULT_FROM_WIN32(ERROR_INVALID_STATE);
-        ExitOnRootFailure(hr, "BA requested to send embedded message when not in embedded mode.");
-    }
-
-    hr = BuffWriteNumber(&pbData, &cbData, dwErrorCode);
-    ExitOnFailure(hr, "Failed to write error code to message buffer.");
 
-    hr = BuffWriteString(&pbData, &cbData, wzMessage ? wzMessage : L"");
-    ExitOnFailure(hr, "Failed to write message string to message buffer.");
-
-    hr = BuffWriteNumber(&pbData, &cbData, dwUIHint);
-    ExitOnFailure(hr, "Failed to write UI hint to message buffer.");
-
-    hr = PipeSendMessage(pContext->pEngineState->embeddedConnection.hPipe, BURN_EMBEDDED_MESSAGE_TYPE_ERROR, pbData, cbData, NULL, NULL, &dwResult);
-    ExitOnFailure(hr, "Failed to send embedded message over pipe.");
-
-    *pnResult = static_cast<int>(dwResult);
+    hr = ExternalEngineSendEmbeddedError(pContext->pEngineState, pArgs->dwErrorCode, pArgs->wzMessage, pArgs->dwUIHint, &pResults->nResult);
 
 LExit:
-    ReleaseBuffer(pbData);
     return hr;
 }
 
@@ -296,34 +178,12 @@ static HRESULT BAEngineSendEmbeddedProgress(
     )
 {
     HRESULT hr = S_OK;
-    BYTE* pbData = NULL;
-    DWORD cbData = 0;
-    DWORD dwResult = 0;
     ValidateMessageArgs(hr, pvArgs, BAENGINE_SENDEMBEDDEDPROGRESS_ARGS, pArgs);
     ValidateMessageResults(hr, pvResults, BAENGINE_SENDEMBEDDEDPROGRESS_RESULTS, pResults);
-    DWORD dwProgressPercentage = pArgs->dwProgressPercentage;
-    DWORD dwOverallProgressPercentage = pArgs->dwOverallProgressPercentage;
-    int* pnResult = &pResults->nResult;
-
-    if (BURN_MODE_EMBEDDED != pContext->pEngineState->mode)
-    {
-        hr = HRESULT_FROM_WIN32(ERROR_INVALID_STATE);
-        ExitOnRootFailure(hr, "BA requested to send embedded progress message when not in embedded mode.");
-    }
-
-    hr = BuffWriteNumber(&pbData, &cbData, dwProgressPercentage);
-    ExitOnFailure(hr, "Failed to write progress percentage to message buffer.");
-
-    hr = BuffWriteNumber(&pbData, &cbData, dwOverallProgressPercentage);
-    ExitOnFailure(hr, "Failed to write overall progress percentage to message buffer.");
-
-    hr = PipeSendMessage(pContext->pEngineState->embeddedConnection.hPipe, BURN_EMBEDDED_MESSAGE_TYPE_PROGRESS, pbData, cbData, NULL, NULL, &dwResult);
-    ExitOnFailure(hr, "Failed to send embedded progress message over pipe.");
 
-    *pnResult = static_cast<int>(dwResult);
+    hr = ExternalEngineSendEmbeddedProgress(pContext->pEngineState, pArgs->dwProgressPercentage, pArgs->dwOverallProgressPercentage, &pResults->nResult);
 
 LExit:
-    ReleaseBuffer(pbData);
     return hr;
 }
 
@@ -334,81 +194,12 @@ static HRESULT BAEngineSetUpdate(
     )
 {
     HRESULT hr = S_OK;
-    LPCWSTR sczId = NULL;
-    LPWSTR sczLocalSource = NULL;
-    LPWSTR sczCommandline = NULL;
-    UUID guid = { };
-    WCHAR wzGuid[39];
-    RPC_STATUS rs = RPC_S_OK;
     ValidateMessageArgs(hr, pvArgs, BAENGINE_SETUPDATE_ARGS, pArgs);
     ValidateMessageResults(hr, pvResults, BAENGINE_SETUPDATE_RESULTS, pResults);
-    LPCWSTR wzLocalSource = pArgs->wzLocalSource;
-    LPCWSTR wzDownloadSource = pArgs->wzDownloadSource;
-    DWORD64 qwSize = pArgs->qwSize;
-    BOOTSTRAPPER_UPDATE_HASH_TYPE hashType = pArgs->hashType;
-    BYTE* rgbHash = pArgs->rgbHash;
-    DWORD cbHash = pArgs->cbHash;
 
-    ::EnterCriticalSection(&pContext->pEngineState->csActive);
-
-    if ((!wzLocalSource || !*wzLocalSource) && (!wzDownloadSource || !*wzDownloadSource))
-    {
-        UpdateUninitialize(&pContext->pEngineState->update);
-    }
-    else if (BOOTSTRAPPER_UPDATE_HASH_TYPE_NONE == hashType && (0 != cbHash || rgbHash))
-    {
-        hr = E_INVALIDARG;
-    }
-    else if (BOOTSTRAPPER_UPDATE_HASH_TYPE_SHA1 == hashType && (SHA1_HASH_LEN != cbHash || !rgbHash))
-    {
-        hr = E_INVALIDARG;
-    }
-    else
-    {
-        UpdateUninitialize(&pContext->pEngineState->update);
-
-        if (!wzLocalSource || !*wzLocalSource)
-        {
-            hr = StrAllocFormatted(&sczLocalSource, L"update\\%ls", pContext->pEngineState->registration.sczExecutableName);
-            ExitOnFailure(hr, "Failed to default local update source");
-        }
-
-        hr = CoreRecreateCommandLine(&sczCommandline, BOOTSTRAPPER_ACTION_INSTALL, pContext->pEngineState->command.display, pContext->pEngineState->command.restart, BOOTSTRAPPER_RELATION_NONE, FALSE, pContext->pEngineState->registration.sczActiveParent, pContext->pEngineState->registration.sczAncestors, NULL, pContext->pEngineState->command.wzCommandLine);
-        ExitOnFailure(hr, "Failed to recreate command-line for update bundle.");
-
-        // Per-user bundles would fail to use the downloaded update bundle, as the existing install would already be cached 
-        // at the registration id's location.  Here I am generating a random guid, but in the future it would be nice if the
-        // feed would provide the ID of the update.
-        if (!pContext->pEngineState->registration.fPerMachine)
-        {
-            rs = ::UuidCreate(&guid);
-            hr = HRESULT_FROM_RPC(rs);
-            ExitOnFailure(hr, "Failed to create bundle update guid.");
-
-            if (!::StringFromGUID2(guid, wzGuid, countof(wzGuid)))
-            {
-                hr = E_OUTOFMEMORY;
-                ExitOnRootFailure(hr, "Failed to convert bundle update guid into string.");
-            }
-
-            sczId = wzGuid;
-        }
-        else
-        {
-            sczId = pContext->pEngineState->registration.sczId;
-        }
-
-        hr = PseudoBundleInitialize(FILEMAKEVERSION(rmj, rmm, rup, rpr), &pContext->pEngineState->update.package, FALSE, sczId, BOOTSTRAPPER_RELATION_UPDATE, BOOTSTRAPPER_PACKAGE_STATE_ABSENT, pContext->pEngineState->registration.sczExecutableName, sczLocalSource ? sczLocalSource : wzLocalSource, wzDownloadSource, qwSize, TRUE, sczCommandline, NULL, NULL, NULL, rgbHash, cbHash);
-        ExitOnFailure(hr, "Failed to set update bundle.");
-
-        pContext->pEngineState->update.fUpdateAvailable = TRUE;
-    }
+    hr = ExternalEngineSetUpdate(pContext->pEngineState, pArgs->wzLocalSource, pArgs->wzDownloadSource, pArgs->qwSize, pArgs->hashType, pArgs->rgbHash, pArgs->cbHash);
 
 LExit:
-    ::LeaveCriticalSection(&pContext->pEngineState->csActive);
-
-    ReleaseStr(sczCommandline);
-    ReleaseStr(sczLocalSource);
     return hr;
 }
 
@@ -419,51 +210,12 @@ static HRESULT BAEngineSetLocalSource(
     )
 {
     HRESULT hr = S_OK;
-    BURN_CONTAINER* pContainer = NULL;
-    BURN_PAYLOAD* pPayload = NULL;
     ValidateMessageArgs(hr, pvArgs, BAENGINE_SETLOCALSOURCE_ARGS, pArgs);
     ValidateMessageResults(hr, pvResults, BAENGINE_SETLOCALSOURCE_RESULTS, pResults);
-    LPCWSTR wzPackageOrContainerId = pArgs->wzPackageOrContainerId;
-    LPCWSTR wzPayloadId = pArgs->wzPayloadId;
-    LPCWSTR wzPath = pArgs->wzPath;
-
-    ::EnterCriticalSection(&pContext->pEngineState->csActive);
-    hr = UserExperienceEnsureEngineInactive(&pContext->pEngineState->userExperience);
-    ExitOnFailure(hr, "Engine is active, cannot change engine state.");
-
-    if (!wzPath || !*wzPath)
-    {
-        hr = E_INVALIDARG;
-    }
-    else if (wzPayloadId && * wzPayloadId)
-    {
-        hr = PayloadFindById(&pContext->pEngineState->payloads, wzPayloadId, &pPayload);
-        ExitOnFailure(hr, "BA requested unknown payload with id: %ls", wzPayloadId);
-
-        if (BURN_PAYLOAD_PACKAGING_EMBEDDED == pPayload->packaging)
-        {
-            hr = HRESULT_FROM_WIN32(ERROR_INVALID_OPERATION);
-            ExitOnFailure(hr, "BA denied while trying to set source on embedded payload: %ls", wzPayloadId);
-        }
 
-        hr = StrAllocString(&pPayload->sczSourcePath, wzPath, 0);
-        ExitOnFailure(hr, "Failed to set source path for payload.");
-    }
-    else if (wzPackageOrContainerId && *wzPackageOrContainerId)
-    {
-        hr = ContainerFindById(&pContext->pEngineState->containers, wzPackageOrContainerId, &pContainer);
-        ExitOnFailure(hr, "BA requested unknown container with id: %ls", wzPackageOrContainerId);
-
-        hr = StrAllocString(&pContainer->sczSourcePath, wzPath, 0);
-        ExitOnFailure(hr, "Failed to set source path for container.");
-    }
-    else
-    {
-        hr = E_INVALIDARG;
-    }
+    hr = ExternalEngineSetLocalSource(pContext->pEngineState, pArgs->wzPackageOrContainerId, pArgs->wzPayloadId, pArgs->wzPath);
 
 LExit:
-    ::LeaveCriticalSection(&pContext->pEngineState->csActive);
     return hr;
 }
 
@@ -474,82 +226,12 @@ static HRESULT BAEngineSetDownloadSource(
     )
 {
     HRESULT hr = S_OK;
-    BURN_CONTAINER* pContainer = NULL;
-    BURN_PAYLOAD* pPayload = NULL;
-    DOWNLOAD_SOURCE* pDownloadSource = NULL;
     ValidateMessageArgs(hr, pvArgs, BAENGINE_SETDOWNLOADSOURCE_ARGS, pArgs);
     ValidateMessageResults(hr, pvResults, BAENGINE_SETDOWNLOADSOURCE_RESULTS, pResults);
-    LPCWSTR wzPackageOrContainerId = pArgs->wzPackageOrContainerId;
-    LPCWSTR wzPayloadId = pArgs->wzPayloadId;
-    LPCWSTR wzUrl = pArgs->wzUrl;
-    LPCWSTR wzUser = pArgs->wzUser;
-    LPCWSTR wzPassword = pArgs->wzPassword;
 
-    ::EnterCriticalSection(&pContext->pEngineState->csActive);
-    hr = UserExperienceEnsureEngineInactive(&pContext->pEngineState->userExperience);
-    ExitOnFailure(hr, "Engine is active, cannot change engine state.");
-
-    if (wzPayloadId && *wzPayloadId)
-    {
-        hr = PayloadFindById(&pContext->pEngineState->payloads, wzPayloadId, &pPayload);
-        ExitOnFailure(hr, "BA requested unknown payload with id: %ls", wzPayloadId);
-
-        if (BURN_PAYLOAD_PACKAGING_EMBEDDED == pPayload->packaging)
-        {
-            hr = HRESULT_FROM_WIN32(ERROR_INVALID_OPERATION);
-            ExitOnFailure(hr, "BA denied while trying to set download URL on embedded payload: %ls", wzPayloadId);
-        }
-
-        pDownloadSource = &pPayload->downloadSource;
-    }
-    else if (wzPackageOrContainerId && *wzPackageOrContainerId)
-    {
-        hr = ContainerFindById(&pContext->pEngineState->containers, wzPackageOrContainerId, &pContainer);
-        ExitOnFailure(hr, "BA requested unknown container with id: %ls", wzPackageOrContainerId);
-
-        pDownloadSource = &pContainer->downloadSource;
-    }
-    else
-    {
-        hr = E_INVALIDARG;
-        ExitOnFailure(hr, "BA did not provide container or payload id.");
-    }
-
-    if (wzUrl && *wzUrl)
-    {
-        hr = StrAllocString(&pDownloadSource->sczUrl, wzUrl, 0);
-        ExitOnFailure(hr, "Failed to set download URL.");
-
-        if (wzUser && *wzUser)
-        {
-            hr = StrAllocString(&pDownloadSource->sczUser, wzUser, 0);
-            ExitOnFailure(hr, "Failed to set download user.");
-
-            if (wzPassword && *wzPassword)
-            {
-                hr = StrAllocString(&pDownloadSource->sczPassword, wzPassword, 0);
-                ExitOnFailure(hr, "Failed to set download password.");
-            }
-            else // no password.
-            {
-                ReleaseNullStr(pDownloadSource->sczPassword);
-            }
-        }
-        else // no user means no password either.
-        {
-            ReleaseNullStr(pDownloadSource->sczUser);
-            ReleaseNullStr(pDownloadSource->sczPassword);
-        }
-    }
-    else // no URL provided means clear out the whole download source.
-    {
-        ReleaseNullStr(pDownloadSource->sczUrl);
-        ReleaseNullStr(pDownloadSource->sczUser);
-        ReleaseNullStr(pDownloadSource->sczPassword);
-    }
+    hr = ExternalEngineSetDownloadSource(pContext->pEngineState, pArgs->wzPackageOrContainerId, pArgs->wzPayloadId, pArgs->wzUrl, pArgs->wzUser, pArgs->wzPassword);
 
 LExit:
-    ::LeaveCriticalSection(&pContext->pEngineState->csActive);
     return hr;
 }
 
@@ -562,19 +244,8 @@ static HRESULT BAEngineSetVariableNumeric(
     HRESULT hr = S_OK;
     ValidateMessageArgs(hr, pvArgs, BAENGINE_SETVARIABLENUMERIC_ARGS, pArgs);
     ValidateMessageResults(hr, pvResults, BAENGINE_SETVARIABLENUMERIC_RESULTS, pResults);
-    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, "BA did not provide variable name.");
-    }
+    hr = ExternalEngineSetVariableNumeric(pContext->pEngineState, pArgs->wzVariable, pArgs->llValue);
 
 LExit:
     return hr;
@@ -589,19 +260,8 @@ static HRESULT BAEngineSetVariableString(
     HRESULT hr = S_OK;
     ValidateMessageArgs(hr, pvArgs, BAENGINE_SETVARIABLESTRING_ARGS, pArgs);
     ValidateMessageResults(hr, pvResults, BAENGINE_SETVARIABLESTRING_RESULTS, pResults);
-    LPCWSTR wzVariable = pArgs->wzVariable;
-    LPCWSTR wzValue = pArgs->wzValue;
 
-    if (wzVariable && *wzVariable)
-    {
-        hr = VariableSetString(&pContext->pEngineState->variables, wzVariable, wzValue, FALSE, pArgs->fFormatted);
-        ExitOnFailure(hr, "Failed to set string variable.");
-    }
-    else
-    {
-        hr = E_INVALIDARG;
-        ExitOnFailure(hr, "BA did not provide variable name.");
-    }
+    hr = ExternalEngineSetVariableString(pContext->pEngineState, pArgs->wzVariable, pArgs->wzValue, pArgs->fFormatted);
 
 LExit:
     return hr;
@@ -614,32 +274,12 @@ static HRESULT BAEngineSetVariableVersion(
     )
 {
     HRESULT hr = S_OK;
-    VERUTIL_VERSION* pVersion = NULL;
     ValidateMessageArgs(hr, pvArgs, BAENGINE_SETVARIABLEVERSION_ARGS, pArgs);
     ValidateMessageResults(hr, pvResults, BAENGINE_SETVARIABLEVERSION_RESULTS, pResults);
-    LPCWSTR wzVariable = pArgs->wzVariable;
-    LPCWSTR wzValue = pArgs->wzValue;
 
-    if (wzVariable && *wzVariable)
-    {
-        if (wzValue)
-        {
-            hr = VerParseVersion(wzValue, 0, FALSE, &pVersion);
-            ExitOnFailure(hr, "Failed to parse new version value.");
-        }
-
-        hr = VariableSetVersion(&pContext->pEngineState->variables, wzVariable, pVersion, FALSE);
-        ExitOnFailure(hr, "Failed to set version variable.");
-    }
-    else
-    {
-        hr = E_INVALIDARG;
-        ExitOnFailure(hr, "BA did not provide variable name.");
-    }
+    hr = ExternalEngineSetVariableVersion(pContext->pEngineState, pArgs->wzVariable, pArgs->wzValue);
 
 LExit:
-    ReleaseVerutilVersion(pVersion);
-
     return hr;
 }
 
@@ -653,11 +293,7 @@ static HRESULT BAEngineCloseSplashScreen(
     ValidateMessageArgs(hr, pvArgs, BAENGINE_CLOSESPLASHSCREEN_ARGS, pArgs);
     ValidateMessageResults(hr, pvResults, BAENGINE_CLOSESPLASHSCREEN_RESULTS, pResults);
 
-    // If the splash screen is still around, close it.
-    if (::IsWindow(pContext->pEngineState->command.hwndSplashScreen))
-    {
-        ::PostMessageW(pContext->pEngineState->command.hwndSplashScreen, WM_CLOSE, 0, 0);
-    }
+    ExternalEngineCloseSplashScreen(pContext->pEngineState);
 
 LExit:
     return hr;
@@ -672,11 +308,8 @@ static HRESULT BAEngineCompareVersions(
     HRESULT hr = S_OK;
     ValidateMessageArgs(hr, pvArgs, BAENGINE_COMPAREVERSIONS_ARGS, pArgs);
     ValidateMessageResults(hr, pvResults, BAENGINE_COMPAREVERSIONS_RESULTS, pResults);
-    LPCWSTR wzVersion1 = pArgs->wzVersion1;
-    LPCWSTR wzVersion2 = pArgs->wzVersion2;
-    int* pnResult = &pResults->nResult;
 
-    hr = VerCompareStringVersions(wzVersion1, wzVersion2, FALSE, pnResult);
+    hr = ExternalEngineCompareVersions(pArgs->wzVersion1, pArgs->wzVersion2, &pResults->nResult);
 
 LExit:
     return hr;
@@ -692,10 +325,7 @@ static HRESULT BAEngineDetect(
     ValidateMessageArgs(hr, pvArgs, BAENGINE_DETECT_ARGS, pArgs);
     ValidateMessageResults(hr, pvResults, BAENGINE_DETECT_RESULTS, pResults);
 
-    if (!::PostThreadMessageW(pContext->dwThreadId, WM_BURN_DETECT, 0, reinterpret_cast<LPARAM>(pArgs->hwndParent)))
-    {
-        ExitWithLastError(hr, "Failed to post detect message.");
-    }
+    hr = ExternalEngineDetect(pContext->dwThreadId, pArgs->hwndParent);
 
 LExit:
     return hr;
@@ -710,12 +340,8 @@ static HRESULT BAEnginePlan(
     HRESULT hr = S_OK;
     ValidateMessageArgs(hr, pvArgs, BAENGINE_PLAN_ARGS, pArgs);
     ValidateMessageResults(hr, pvResults, BAENGINE_PLAN_RESULTS, pResults);
-    BOOTSTRAPPER_ACTION action = pArgs->action;
 
-    if (!::PostThreadMessageW(pContext->dwThreadId, WM_BURN_PLAN, 0, action))
-    {
-        ExitWithLastError(hr, "Failed to post plan message.");
-    }
+    hr = ExternalEnginePlan(pContext->dwThreadId, pArgs->action);
 
 LExit:
     return hr;
@@ -731,14 +357,7 @@ static HRESULT BAEngineElevate(
     ValidateMessageArgs(hr, pvArgs, BAENGINE_ELEVATE_ARGS, pArgs);
     ValidateMessageResults(hr, pvResults, BAENGINE_ELEVATE_RESULTS, pResults);
 
-    if (INVALID_HANDLE_VALUE != pContext->pEngineState->companionConnection.hPipe)
-    {
-        hr = HRESULT_FROM_WIN32(ERROR_ALREADY_INITIALIZED);
-    }
-    else if (!::PostThreadMessageW(pContext->dwThreadId, WM_BURN_ELEVATE, 0, reinterpret_cast<LPARAM>(pArgs->hwndParent)))
-    {
-        ExitWithLastError(hr, "Failed to post elevate message.");
-    }
+    hr = ExternalEngineElevate(pContext->pEngineState, pContext->dwThreadId, pArgs->hwndParent);
 
 LExit:
     return hr;
@@ -754,16 +373,7 @@ static HRESULT BAEngineApply(
     ValidateMessageArgs(hr, pvArgs, BAENGINE_APPLY_ARGS, pArgs);
     ValidateMessageResults(hr, pvResults, BAENGINE_APPLY_RESULTS, pResults);
 
-    ExitOnNull(pArgs->hwndParent, hr, E_INVALIDARG, "BA passed NULL hwndParent to Apply.");
-    if (!::IsWindow(pArgs->hwndParent))
-    {
-        ExitOnFailure(hr = E_INVALIDARG, "BA passed invalid hwndParent to Apply.");
-    }
-
-    if (!::PostThreadMessageW(pContext->dwThreadId, WM_BURN_APPLY, 0, reinterpret_cast<LPARAM>(pArgs->hwndParent)))
-    {
-        ExitWithLastError(hr, "Failed to post apply message.");
-    }
+    hr = ExternalEngineApply(pContext->dwThreadId, pArgs->hwndParent);
 
 LExit:
     return hr;
@@ -779,10 +389,7 @@ static HRESULT BAEngineQuit(
     ValidateMessageArgs(hr, pvArgs, BAENGINE_QUIT_ARGS, pArgs);
     ValidateMessageResults(hr, pvResults, BAENGINE_QUIT_RESULTS, pResults);
 
-    if (!::PostThreadMessageW(pContext->dwThreadId, WM_BURN_QUIT, static_cast<WPARAM>(pArgs->dwExitCode), 0))
-    {
-        ExitWithLastError(hr, "Failed to post shutdown message.");
-    }
+    hr = ExternalEngineQuit(pContext->dwThreadId, pArgs->dwExitCode);
 
 LExit:
     return hr;
@@ -795,64 +402,12 @@ static HRESULT BAEngineLaunchApprovedExe(
     )
 {
     HRESULT hr = S_OK;
-    BURN_APPROVED_EXE* pApprovedExe = NULL;
-    BOOL fLeaveCriticalSection = FALSE;
-    BURN_LAUNCH_APPROVED_EXE* pLaunchApprovedExe = NULL;
     ValidateMessageArgs(hr, pvArgs, BAENGINE_LAUNCHAPPROVEDEXE_ARGS, pArgs);
     ValidateMessageResults(hr, pvResults, BAENGINE_LAUNCHAPPROVEDEXE_RESULTS, pResults);
-    HWND hwndParent = pArgs->hwndParent;
-    LPCWSTR wzApprovedExeForElevationId = pArgs->wzApprovedExeForElevationId;
-    LPCWSTR wzArguments = pArgs->wzArguments;
-    DWORD dwWaitForInputIdleTimeout = pArgs->dwWaitForInputIdleTimeout;
 
-    pLaunchApprovedExe = (BURN_LAUNCH_APPROVED_EXE*)MemAlloc(sizeof(BURN_LAUNCH_APPROVED_EXE), TRUE);
-    ExitOnNull(pLaunchApprovedExe, hr, E_OUTOFMEMORY, "Failed to alloc BURN_LAUNCH_APPROVED_EXE");
-
-    ::EnterCriticalSection(&pContext->pEngineState->csActive);
-    fLeaveCriticalSection = TRUE;
-    hr = UserExperienceEnsureEngineInactive(&pContext->pEngineState->userExperience);
-    ExitOnFailure(hr, "Engine is active, cannot change engine state.");
-
-    if (!wzApprovedExeForElevationId || !*wzApprovedExeForElevationId)
-    {
-        ExitFunction1(hr = E_INVALIDARG);
-    }
-
-    hr = ApprovedExesFindById(&pContext->pEngineState->approvedExes, wzApprovedExeForElevationId, &pApprovedExe);
-    ExitOnFailure(hr, "BA requested unknown approved exe with id: %ls", wzApprovedExeForElevationId);
-
-    ::LeaveCriticalSection(&pContext->pEngineState->csActive);
-    fLeaveCriticalSection = FALSE;
-
-    hr = StrAllocString(&pLaunchApprovedExe->sczId, wzApprovedExeForElevationId, NULL);
-    ExitOnFailure(hr, "Failed to copy the id.");
-
-    if (wzArguments)
-    {
-        hr = StrAllocString(&pLaunchApprovedExe->sczArguments, wzArguments, NULL);
-        ExitOnFailure(hr, "Failed to copy the arguments.");
-    }
-
-    pLaunchApprovedExe->dwWaitForInputIdleTimeout = dwWaitForInputIdleTimeout;
-
-    pLaunchApprovedExe->hwndParent = hwndParent;
-
-    if (!::PostThreadMessageW(pContext->dwThreadId, WM_BURN_LAUNCH_APPROVED_EXE, 0, reinterpret_cast<LPARAM>(pLaunchApprovedExe)))
-    {
-        ExitWithLastError(hr, "Failed to post launch approved exe message.");
-    }
+    hr = ExternalEngineLaunchApprovedExe(pContext->pEngineState, pContext->dwThreadId, pArgs->hwndParent, pArgs->wzApprovedExeForElevationId, pArgs->wzArguments, pArgs->dwWaitForInputIdleTimeout);
 
 LExit:
-    if (fLeaveCriticalSection)
-    {
-        ::LeaveCriticalSection(&pContext->pEngineState->csActive);
-    }
-
-    if (FAILED(hr))
-    {
-        ApprovedExesUninitializeLaunch(pLaunchApprovedExe);
-    }
-
     return hr;
 }
 
@@ -953,34 +508,3 @@ HRESULT WINAPI EngineForApplicationProc(
 LExit:
     return hr;
 }
-
-static HRESULT CopyStringToBA(
-    __in LPWSTR wzValue,
-    __in_opt LPWSTR wzBuffer,
-    __inout DWORD* pcchBuffer
-    )
-{
-    HRESULT hr = S_OK;
-    BOOL fTooSmall = !wzBuffer;
-
-    if (!fTooSmall)
-    {
-        hr = ::StringCchCopyExW(wzBuffer, *pcchBuffer, wzValue, NULL, NULL, STRSAFE_FILL_BEHIND_NULL);
-        if (STRSAFE_E_INSUFFICIENT_BUFFER == hr)
-        {
-            fTooSmall = TRUE;
-        }
-    }
-
-    if (fTooSmall)
-    {
-        hr = ::StringCchLengthW(wzValue, STRSAFE_MAX_CCH, reinterpret_cast<size_t*>(pcchBuffer));
-        if (SUCCEEDED(hr))
-        {
-            hr = E_MOREDATA;
-            *pcchBuffer += 1; // null terminator.
-        }
-    }
-
-    return hr;
-}