MUI: exemplo de configurações de Application-Specific (pré-Windows Vista)

O aplicativo de exemplo descrito neste tópico é semelhante ao mostrado em MUI: exemplo de configurações de Application-Specific (Windows Vista), exceto que esse aplicativo será executado no Windows 2000 e posterior. A diferença main do outro exemplo é que o fallback de linguagem deve ser personalizado para ser executado em vários sistemas operacionais.

Esse aplicativo primeiro analisa uma lista de idiomas delimitada em um arquivo de texto e a converte em uma lista de idiomas de várias cadeias de caracteres para definir as preferências de idioma específicas do aplicativo. Os delimitadores com suporte no exemplo são ",", ";", ":" e " ". Depois de analisar a lista, o código localiza e carrega os recursos no idioma identificado. Em contraste com o outro exemplo de configurações específicas do aplicativo, esse código carrega e libera arquivos de recurso usando chamadas para as funções MUI LoadMUILibrary e FreeMUILibrary.

// Down-Level enabled application that will work with Windows 2000 and later

#include <windows.h>
#include <wchar.h>
#include <strsafe.h>
#include <Nlsdl.h>
#include <MUILoad.h>
#include "resource.h"

#define SUFFICIENTLY_LARGE_STRING_BUFFER (MAX_PATH*2)
#define USER_CONFIGURATION_STRING_BUFFER (((LOCALE_NAME_MAX_LENGTH+1)*5)+1)
#define SUFFICIENTLY_LARGE_ERROR_BUFFER (1024*2)

BOOL GetMyUserDefinedLanguages(WCHAR * langStr, DWORD langStrSize);
BOOL ConvertMyLangStrToMultiLangStr(WCHAR * langStr, WCHAR * langMultiStr, DWORD langMultiStrSize);

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
    UNREFERENCED_PARAMETER(hInstance);
    UNREFERENCED_PARAMETER(hPrevInstance);
    UNREFERENCED_PARAMETER(lpCmdLine);
    UNREFERENCED_PARAMETER(nCmdShow);

    // The following code presents a hypothetical, yet common use pattern of MUI technology
    WCHAR displayBuffer[SUFFICIENTLY_LARGE_ERROR_BUFFER];

    // 1. Application starts by applying any user defined language preferences
    // (language setting is potentially optional for an application that wishes to strictly use OS system language fallback)
    // 1a. Application looks in pre-defined location for user preferences (registry, file, web, etc.)
    WCHAR userLanguagesString[USER_CONFIGURATION_STRING_BUFFER*2];
    if(!GetMyUserDefinedLanguages(userLanguagesString,USER_CONFIGURATION_STRING_BUFFER*2))
    {
        swprintf_s(displayBuffer,SUFFICIENTLY_LARGE_ERROR_BUFFER,L"FAILURE: Unable to find the user defined language configuration, last error = %d.",GetLastError());
        MessageBoxW(NULL,displayBuffer,L"HelloMUI ERROR!",MB_OK | MB_ICONERROR);
        return 1; // exit
    }
    // 1b. Application converts the user defined 'readable' languages to the proper multi-string 'less readable' language name format
    WCHAR userLanguagesMultiString[USER_CONFIGURATION_STRING_BUFFER];
    if(!ConvertMyLangStrToMultiLangStr(userLanguagesString,userLanguagesMultiString,USER_CONFIGURATION_STRING_BUFFER))
    {
        swprintf_s(displayBuffer,SUFFICIENTLY_LARGE_ERROR_BUFFER,L"FAILURE: Unable to convert the user defined language configuration to multi-string, last error = %d.",GetLastError());
        MessageBoxW(NULL,displayBuffer,L"HelloMUI ERROR!",MB_OK | MB_ICONERROR);
        return 1; // exit
    }
    // 1c. Application now attempts to set the fallback list - this is much different for a down-level 
    // shipping application when compared to a Vista or Windows 7  only shipping application    
    BOOL setSuccess = FALSE;
    DWORD setLangCount = 0;
    HMODULE hDLL = GetModuleHandleW(L"kernel32.dll");
    if( hDLL )
    {
        typedef BOOL (* SET_PREFERRED_UI_LANGUAGES_PROTOTYPE ) ( DWORD, PCWSTR, PULONG );
        SET_PREFERRED_UI_LANGUAGES_PROTOTYPE fp_SetPreferredUILanguages = (SET_PREFERRED_UI_LANGUAGES_PROTOTYPE)NULL;
        fp_SetPreferredUILanguages = (SET_PREFERRED_UI_LANGUAGES_PROTOTYPE) GetProcAddress(hDLL,"SetProcessPreferredUILanguages");
        if( fp_SetPreferredUILanguages )
        {
            // call SetProcessPreferredUILanguages if it is available in Kernel32.dll's export table - Windows 7 and later
            setSuccess = fp_SetPreferredUILanguages(MUI_LANGUAGE_NAME,userLanguagesMultiString,&setLangCount);
        }
        else
        {
            fp_SetPreferredUILanguages = (SET_PREFERRED_UI_LANGUAGES_PROTOTYPE) GetProcAddress(hDLL,"SetThreadPreferredUILanguages");
            // call SetThreadPreferredUILanguages if it is available in Kernel32.dll's export table - Windows Vista and later
            if(fp_SetPreferredUILanguages)
                setSuccess = fp_SetPreferredUILanguages(MUI_LANGUAGE_NAME,userLanguagesMultiString,&setLangCount);
        }
    }

    // 2. Application obtains access to the proper resource container 
    // for standard Win32 resource loading this is normally a PE module
    // LoadMUILibrary is the preferred alternative for loading of resource modules
    // when the application is potentially run on OS versions prior to Vista
    // LoadMUILibrary is available via Windows SDK releases in Vista and later
    // When available, it is advised to get the most up-to-date Windows SDK (e.g., Windows 7)
    HMODULE resContainer = NULL;
    if(setSuccess) // Vista and later OS scenario
    {
        resContainer = LoadMUILibraryW(HELLO_MODULE_CONTRIVED_FILE_PATH,MUI_LANGUAGE_NAME,0);
    }
    else // this block should only be hit on XP and earlier OS platforms as setSuccess will be TRUE on Vista and later
    {
        // need to provide your own fallback mechanism such as the implementation below
        // in essence the application will iterate through the user configured language list
        WCHAR * next = userLanguagesMultiString;
        while(!resContainer && *next != L'\0')
        {
            // convert the language name to an appropriate LCID
            // DownlevelLocaleNameToLCID is available via standalone download package 
            // and is contained in Nlsdl.h / Nlsdl.lib
            LCID nextLcid = DownlevelLocaleNameToLCID(next,DOWNLEVEL_LOCALE_NAME);
            // then have LoadMUILibrary attempt to probe for the right .mui module
            resContainer = LoadMUILibraryW(HELLO_MODULE_CONTRIVED_FILE_PATH,MUI_LANGUAGE_NAME,(LANGID)nextLcid);
            // increment to the next language name in our list
            size_t nextStrLen = 0;
            if(SUCCEEDED(StringCchLengthW(next,LOCALE_NAME_MAX_LENGTH,&nextStrLen)))
                next += (nextStrLen + 1);
            else
                break; // string is invalid - need to exit
        }
        // if the user configured list did not locate a module then try the languages associated with the system
        if(!resContainer)
            resContainer = LoadMUILibraryW(HELLO_MODULE_CONTRIVED_FILE_PATH,MUI_LANGUAGE_NAME,0);
    }
    if(!resContainer)
    {
        swprintf_s(displayBuffer,SUFFICIENTLY_LARGE_ERROR_BUFFER,L"FAILURE: Unable to load the resource container module, last error = %d.",GetLastError());
        MessageBoxW(NULL,displayBuffer,L"HelloMUI ERROR!",MB_OK | MB_ICONERROR);
        return 1; // exit
    }

    // 3. Application parses the resource container to find the appropriate item
    WCHAR szHello[SUFFICIENTLY_LARGE_STRING_BUFFER];
    if(LoadStringW(resContainer,HELLO_MUI_STR_0,szHello,SUFFICIENTLY_LARGE_STRING_BUFFER) == 0)
    {
        swprintf_s(displayBuffer,SUFFICIENTLY_LARGE_ERROR_BUFFER,L"FAILURE: Unable to load the resource string, last error = %d.",GetLastError());
        MessageBoxW(NULL,displayBuffer,L"HelloMUI ERROR!",MB_OK | MB_ICONERROR);
        FreeLibrary(resContainer);
        return 1; // exit
    }

    // 4. Application presents the discovered resource to the user via UI
    swprintf_s(displayBuffer,SUFFICIENTLY_LARGE_ERROR_BUFFER,L"%s MUI",szHello);
    MessageBoxW(NULL,displayBuffer,L"HelloMUI",MB_OK | MB_ICONINFORMATION);

    // 5. Application cleans up memory associated with the resource container after this item is no longer needed.
    if(!FreeMUILibrary(resContainer))
    {
        swprintf_s(displayBuffer,SUFFICIENTLY_LARGE_ERROR_BUFFER,L"FAILURE: Unable to unload the resource container, last error = %d.",GetLastError());
        MessageBoxW(NULL,displayBuffer,L"HelloMUI ERROR!",MB_OK | MB_ICONERROR);
        return 1; // exit
    }

    return 0;
}

BOOL GetMyUserDefinedLanguages(WCHAR * langStr, DWORD langStrSize)
{
    BOOL rtnVal = FALSE;
    // very simple implementation - assumes that first 'langStrSize' characters of the 
    // L".\\langs.txt" file comprises a string of one or more languages
    HANDLE langConfigFileHandle = CreateFileW(L".\\langs.txt", GENERIC_READ, 0, 
        NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
    if(langConfigFileHandle != INVALID_HANDLE_VALUE)
    {
        // clear out the input variables
        DWORD bytesActuallyRead = 0;
        if(ReadFile(langConfigFileHandle,langStr,langStrSize*sizeof(WCHAR),&bytesActuallyRead,NULL) && bytesActuallyRead > 0)
        {
            rtnVal = TRUE;
            DWORD nullIndex = (bytesActuallyRead/sizeof(WCHAR) < langStrSize) ? bytesActuallyRead/sizeof(WCHAR) : langStrSize;
            langStr[nullIndex] = L'\0';
        }
        CloseHandle(langConfigFileHandle);
    }
    return rtnVal;
}

BOOL ConvertMyLangStrToMultiLangStr(WCHAR * langStr, WCHAR * langMultiStr, DWORD langMultiStrSize)
{
    BOOL rtnVal = FALSE;
    size_t strLen = 0;
    rtnVal = SUCCEEDED(StringCchLengthW(langStr,USER_CONFIGURATION_STRING_BUFFER*2,&strLen));
    if(rtnVal && strLen > 0 && langMultiStr && langMultiStrSize > 0)
    {
        WCHAR * langMultiStrPtr = langMultiStr;
        WCHAR * last = langStr + (langStr[0] == 0xFEFF ? 1 : 0);
        WCHAR * context = last;
        WCHAR * next = wcstok_s(last,L",; :",&context);
        while(next && rtnVal)
        {
            // make sure you validate the user input
            if(SUCCEEDED(StringCchLengthW(last,LOCALE_NAME_MAX_LENGTH,&strLen)) 
                && DownlevelLocaleNameToLCID(next,0) != 0)
            {
                langMultiStrPtr[0] = L'\0';
                rtnVal &= SUCCEEDED(StringCchCatW(langMultiStrPtr,(langMultiStrSize - (langMultiStrPtr - langMultiStr)),next));
                langMultiStrPtr += strLen + 1;
            }
            next = wcstok_s(NULL,L",; :",&context);
            if(next)
                last = next;
        }
        if(rtnVal && (langMultiStrSize - (langMultiStrPtr - langMultiStr))) // make sure there is a double null term for the multi-string 
        {
            langMultiStrPtr[0] = L'\0';
        }
        else // fail and guard anyone whom might use the multi-string
        {
            langMultiStr[0] = L'\0';
            langMultiStr[1] = L'\0';
        }
    }
    return rtnVal;
}