UWP Loader: A stub dynamic link library to load other dynamic link libraries into a UWP app in one go.

UWP.Loader.c

#define _MINAPPMODEL_H_
#include <initguid.h>
#include <windows.h>
#include <windows.data.json.h>
#include <roapi.h>
#include <winstring.h>
#include <appmodel.h>

DWORD ThreadProc(LPVOID lpParameter)
{
    RoInitialize(RO_INIT_SINGLETHREADED);

    WCHAR szPathName[MAX_PATH] = {};
    ExpandEnvironmentStringsW(L"%LOCALAPPDATA%\\..\\RoamingState\\UWP.Loader\\", szPathName, MAX_PATH);

    WCHAR szFileName[MAX_PATH] = {};
    HANDLE hFile =
        CreateFile2(lstrcatW(lstrcpyW(szFileName, szPathName), L".json"), FILE_READ_DATA, 0, OPEN_EXISTING, NULL);
    if (hFile == INVALID_HANDLE_VALUE)
        goto _;

    INT cbMultiByte = GetFileSize(hFile, NULL);
    LPSTR lpMultiByteStr = HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, cbMultiByte + 1);
    ReadFile(hFile, lpMultiByteStr, cbMultiByte, NULL, NULL);
    CloseHandle(hFile);

    INT cchWideChar = MultiByteToWideChar(CP_UTF8, 0, lpMultiByteStr, cbMultiByte, NULL, 0);
    LPWSTR lpWideCharStr = HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, sizeof(WCHAR) * (cchWideChar + 1));
    MultiByteToWideChar(CP_UTF8, 0, lpMultiByteStr, cbMultiByte, lpWideCharStr, cchWideChar);
    HeapFree(GetProcessHeap(), 0, lpMultiByteStr);

    HSTRING hString = NULL;
    WindowsCreateString(lpWideCharStr, cchWideChar, &hString);
    HeapFree(GetProcessHeap(), 0, lpWideCharStr);

    HSTRING pActivatableClassId = NULL;
    WindowsCreateString(RuntimeClass_Windows_Data_Json_JsonValue, lstrlenW(RuntimeClass_Windows_Data_Json_JsonValue),
                        &pActivatableClassId);

    __x_ABI_CWindows_CData_CJson_CIJsonValueStatics *pJsonValueStatics = NULL;
    RoGetActivationFactory(pActivatableClassId, &IID___x_ABI_CWindows_CData_CJson_CIJsonValueStatics,
                           (void **)&pJsonValueStatics);
    WindowsDeleteString(pActivatableClassId);

    boolean fSuccess = FALSE;
    __x_ABI_CWindows_CData_CJson_CIJsonValue *pJsonValue = NULL;
    pJsonValueStatics->lpVtbl->TryParse(pJsonValueStatics, hString, &pJsonValue, &fSuccess);
    pJsonValueStatics->lpVtbl->Release(pJsonValueStatics);
    WindowsDeleteString(hString);

    if (fSuccess)
    {
        __x_ABI_CWindows_CData_CJson_CIJsonArray *pJsonArray = NULL;
        pJsonValue->lpVtbl->GetArray(pJsonValue, &pJsonArray);

        if (pJsonArray)
        {
            __FIVector_1_Windows__CData__CJson__CIJsonValue *pVector = NULL;
            pJsonArray->lpVtbl->QueryInterface(pJsonArray, &IID___FIVector_1_Windows__CData__CJson__CIJsonValue,
                                               (void **)&pVector);

            UINT32 nLength = 0;
            pVector->lpVtbl->get_Size(pVector, &nLength);
            pVector->lpVtbl->Release(pVector);

            for (UINT32 _ = 0; _ < nLength; _++)
            {
                HSTRING hString = NULL;
                pJsonArray->lpVtbl->GetStringAt(pJsonArray, _, &hString);
                if (hString)
                    LoadLibraryW(
                        lstrcatW(lstrcpyW(szFileName, szPathName),
                                 WindowsGetStringRawBuffer(hString, &((UINT32){WindowsGetStringLen(hString)}))));
            }

            pJsonArray->lpVtbl->Release(pJsonArray);
        }
        pJsonValue->lpVtbl->Release(pJsonValue);
    }

_:
    RoUninitialize();
    FreeLibraryAndExitThread(lpParameter, 0);
    return 0;
}

BOOL DllMainCRTStartup(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved)
{
    if (fdwReason == DLL_PROCESS_ATTACH)
    {
        if (GetCurrentPackageFamilyName(&((UINT32){}), NULL) == APPMODEL_ERROR_NO_PACKAGE)
            return FALSE;

        DisableThreadLibraryCalls(hinstDLL);
        CloseHandle(CreateThread(NULL, 0, ThreadProc, hinstDLL, 0, NULL));
    }
    return TRUE;
}