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Требуется уточнение для преобразования путей в длинные пути Unicode или те, которые начинаются с \\? \

Прежде всего, позвольте мне задать риторический вопрос - Microsoft, зачем нам добавлять пути с \\?\, чтобы они имели длину 32 767 символов? Почему бы просто не использовать их as-is и расширить размер внутренних буферов на API? Извините, я просто разочаровываю свое разочарование...

Хорошо, теперь мой фактический вопрос, скажем, если у меня есть путь, как его преобразовать в формат, принимающий длину 32 767 символов? Обратите внимание, что я ничего не знаю об этом пути - это может быть относительный путь, абсолютный локальный путь, сетевой ресурс и т.д. Другими словами, это может быть любой из тех множеств форматов пути, которые Microsoft изобрела.

Поначалу кажется простым предложением добавить \\?\ в начале, правильно? Что ж, если этот путь уже преобразован в расширенный формат? Я пробовал прочитать это, и из размера этой страницы и количества комментариев внизу вы можете видеть, что все не так просто, как кажется.

4b9b3361

ОТВЕТЫ

Ответ 1

OK. Это оказывается не таким простым, как кажется. Камнем преткновения (помимо нечеткой документации и несметным количеством форматов пути) является то, что некоторые API даже не работают, как рекламируются во всех версиях ОС.

В любом случае, вот что я придумал, похоже, работает на XP SP3, Vista, Windows 7 и 8. Несколько больших, также написанных для MFC, но это только для управления строкой. У меня нет времени его настроить:

enum PATH_PREFIX_TYPE
{
    PPT_UNKNOWN,
    PPT_ABSOLUTE,           //Found absolute path that is none of the other types
    PPT_UNC,                //Found \\server\share\ prefix
    PPT_LONG_UNICODE,       //Found \\?\ prefix
    PPT_LONG_UNICODE_UNC,   //Found \\?\UNC\ prefix
};

CString MakeUnicodeLargePath(LPCTSTR pPath)
{
    //Convert path from 'pPath' into a larger Unicode path, that allows up to 32,767 character length
    //RETURN:
    //      = Resulting path
    CString strPath;

    if(pPath &&
        pPath[0] != 0)
    {
        //Determine the type of the existing prefix
        PATH_PREFIX_TYPE ppt;
        GetOffsetAfterPathRoot(pPath, &ppt);

        //Assume path to be without change
        strPath = pPath;

        switch(ppt)
        {
        case PPT_ABSOLUTE:
            {
                //First we need to check if its an absolute path relative to the root
                BOOL bOK2AddPrefix = TRUE;
                if(strPath.GetLength() >= 1 &&
                    (strPath[0] == L'\\' || strPath[0] == L'/'))
                {
                    bOK2AddPrefix = FALSE;

                    //Get current root path
                    TCHAR chDummy[1];
                    DWORD dwLnSz = GetCurrentDirectory(0, chDummy);
                    if(dwLnSz)
                    {
                        TCHAR* pBuff = new (std::nothrow) TCHAR[dwLnSz];
                        if(pBuff)
                        {
                            if(GetCurrentDirectory(dwLnSz, pBuff) == dwLnSz - 1)
                            {
                                int nIndFollowing = GetOffsetAfterPathRoot(pBuff);
                                if(nIndFollowing > 0)
                                {
                                    bOK2AddPrefix = TRUE;
                                    CString strRoot = pBuff;
                                    strPath = strRoot.Left(nIndFollowing) + strPath.Right(strPath.GetLength() - 1);
                                }
                            }

                            delete[] pBuff;
                            pBuff = NULL;
                        }
                    }
                }

                if(bOK2AddPrefix)
                {
                    //Add \\?\ prefix
                    strPath = L"\\\\?\\" + strPath;
                }
            }
            break;

        case PPT_UNC:
            {
                //First we need to remove the opening slashes for UNC share
                if(strPath.GetLength() >= 2 &&
                    (strPath[0] == L'\\' || strPath[0] == L'/') &&
                    (strPath[1] == L'\\' || strPath[1] == L'/')
                    )
                {
                    strPath = strPath.Right(strPath.GetLength() - 2);
                }

                //Add \\?\UNC\ prefix
                strPath = L"\\\\?\\UNC\\" + strPath;
            }
            break;
        }
    }

    return strPath;
}

LPCTSTR PathSkipRoot_CorrectedForMicrosoftStupidity(LPCTSTR pszPath)
{
    //Correction for PathSkipRoot API
    CString strPath = pszPath;

    //Replace all / with \ because PathSkipRoot can't handle /'s
    strPath.Replace(L'/', L'\\');

    //Now call the API
    LPCTSTR pResBuff = PathSkipRoot(strPath.GetString());

    return pResBuff ? pszPath + (UINT)(pResBuff - strPath.GetString()) : NULL;
}

BOOL PathIsRelative_CorrectedForMicrosoftStupidity(LPCTSTR pszPath)
{
    //Correction for PathIsRelative API
    CString strPath = pszPath;

    //Replace all / with \ because PathIsRelative can't handle /'s
    strPath.Replace(L'/', L'\\');

    //Now call the API
    return PathIsRelative(strPath);
}

int GetOffsetAfterPathRoot(LPCTSTR pPath, PATH_PREFIX_TYPE* pOutPrefixType)
{
    //Checks if 'pPath' begins with the drive, share, prefix, etc
    //EXAMPLES:
    //   Path                          Return:   Points at:                 PrefixType:
    //  Relative\Folder\File.txt        0         Relative\Folder\File.txt   PPT_UNKNOWN
    //  \RelativeToRoot\Folder          1         RelativeToRoot\Folder      PPT_ABSOLUTE
    //  C:\Windows\Folder               3         Windows\Folder             PPT_ABSOLUTE
    //  \\server\share\Desktop          15        Desktop                    PPT_UNC
    //  \\?\C:\Windows\Folder           7         Windows\Folder             PPT_LONG_UNICODE
    //  \\?\UNC\server\share\Desktop    21        Desktop                    PPT_LONG_UNICODE_UNC
    //RETURN:
    //      = Index in 'pPath' after the root, or
    //      = 0 if no root was found
    int nRetInd = 0;
    PATH_PREFIX_TYPE ppt = PPT_UNKNOWN;

    if(pPath &&
        pPath[0] != 0)
    {
        int nLen = lstrlen(pPath);

        //Determine version of Windows
        OSVERSIONINFO osi;
        osi.dwOSVersionInfoSize = sizeof(osi);
        BOOL bWinXPOnly = GetVersionEx(&osi) && osi.dwMajorVersion <= 5;

        //The PathSkipRoot() API doesn't work correctly on Windows XP
        if(!bWinXPOnly)
        {
            //Works since Vista and up, but still needs correction :)
            LPCTSTR pPath2 = PathSkipRoot_CorrectedForMicrosoftStupidity(pPath);
            if(pPath2 &&
                pPath2 >= pPath)
            {
                nRetInd = pPath2 - pPath;
            }
        }

        //Now determine the type of prefix
        int nIndCheckUNC = -1;

        if(nLen >= 8 &&
            (pPath[0] == L'\\' || pPath[0] == L'/') &&
            (pPath[1] == L'\\' || pPath[1] == L'/') &&
            pPath[2] == L'?' &&
            (pPath[3] == L'\\' || pPath[3] == L'/') &&
            (pPath[4] == L'U' || pPath[4] == L'u') &&
            (pPath[5] == L'N' || pPath[5] == L'n') &&
            (pPath[6] == L'C' || pPath[6] == L'c') &&
            (pPath[7] == L'\\' || pPath[7] == L'/')
            )
        {
            //Found \\?\UNC\ prefix
            ppt = PPT_LONG_UNICODE_UNC;

            if(bWinXPOnly)
            {
                //For older OS
                nRetInd += 8;
            }

            //Check for UNC share later
            nIndCheckUNC = 8;
        }
        else if(nLen >= 4 &&
            (pPath[0] == L'\\' || pPath[0] == L'/') &&
            (pPath[1] == L'\\' || pPath[1] == L'/') &&
            pPath[2] == L'?' &&
            (pPath[3] == L'\\' || pPath[3] == L'/')
            )
        {
            //Found \\?\ prefix
            ppt = PPT_LONG_UNICODE;

            if(bWinXPOnly)
            {
                //For older OS
                nRetInd += 4;
            }
        }
        else if(nLen >= 2 &&
            (pPath[0] == L'\\' || pPath[0] == L'/') &&
            (pPath[1] == L'\\' || pPath[1] == L'/')
            )
        {
            //Check for UNC share later
            nIndCheckUNC = 2;
        }

        if(nIndCheckUNC >= 0)
        {
            //Check for UNC, i.e. \\server\share\ part
            int i = nIndCheckUNC;
            for(int nSkipSlashes = 2; nSkipSlashes > 0; nSkipSlashes--)
            {
                for(; i < nLen; i++)
                {
                    TCHAR z = pPath[i];
                    if(z == L'\\' ||
                        z == L'/' ||
                        i + 1 >= nLen)
                    {
                        i++;
                        if(nSkipSlashes == 1)
                        {
                            if(ppt == PPT_UNKNOWN)
                                ppt = PPT_UNC;

                            if(bWinXPOnly)
                            {
                                //For older OS
                                nRetInd = i;
                            }
                        }

                        break;
                    }
                }
            }
        }

        if(bWinXPOnly)
        {
            //Only if we didn't determine any other type
            if(ppt == PPT_UNKNOWN)
            {
                if(!PathIsRelative_CorrectedForMicrosoftStupidity(pPath + nRetInd))
                {
                    ppt = PPT_ABSOLUTE;
                }
            }

            //For older OS only
            LPCTSTR pPath2 = PathSkipRoot_CorrectedForMicrosoftStupidity(pPath + nRetInd);
            if(pPath2 &&
                pPath2 >= pPath)
            {
                nRetInd = pPath2 - pPath;
            }

        }
        else
        {
            //Only if we didn't determine any other type
            if(ppt == PPT_UNKNOWN)
            {
                if(!PathIsRelative_CorrectedForMicrosoftStupidity(pPath))
                {
                    ppt = PPT_ABSOLUTE;
                }
            }
        }
    }

    if(pOutPrefixType)
        *pOutPrefixType = ppt;

    return nRetInd;
}

И вот как я его тестирую:

_tprintf(MakeUnicodeLargePath(L""));
_tprintf(L"\n");
_tprintf(MakeUnicodeLargePath(L"C:\\Ba*d\\P|a?t<h>\\Windows\\Folder"));
_tprintf(L"\n");
_tprintf(MakeUnicodeLargePath(L"Relative\\Folder\\File.txt"));
_tprintf(L"\n");
_tprintf(MakeUnicodeLargePath(L"C:\\Windows\\Folder"));
_tprintf(L"\n");
_tprintf(MakeUnicodeLargePath(L"\\\\?\\C:\\Windows\\Folder"));
_tprintf(L"\n");
_tprintf(MakeUnicodeLargePath(L"\\\\?\\UNC\\server\\share\\Desktop"));
_tprintf(L"\n");
_tprintf(MakeUnicodeLargePath(L"\\\\?\\unC\\server\\share\\Desktop\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path"));
_tprintf(L"\n");
_tprintf(MakeUnicodeLargePath(L"\\\\server\\share\\Desktop\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path"));
_tprintf(L"\n");
_tprintf(MakeUnicodeLargePath(L"C:\\Desktop\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path"));
_tprintf(L"\n");
_tprintf(MakeUnicodeLargePath(L"\\AbsoluteToRoot\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path\\Very Long path"));
_tprintf(L"\n");
_tprintf(MakeUnicodeLargePath(L"\\\\server\\share\\Desktop"));
_tprintf(L"\n");
_tprintf(MakeUnicodeLargePath(L"\\\\?\\UNC\\\\share\\folder\\Desktop"));
_tprintf(L"\n");
_tprintf(MakeUnicodeLargePath(L"\\\\server\\share"));
_tprintf(L"\n");

И это результат, который я получаю:

\\?\C:\Ba*d\P|a?t<h>\Windows\Folder
Relative\Folder\File.txt
\\?\C:\Windows\Folder
\\?\C:\Windows\Folder
\\?\UNC\server\share\Desktop
\\?\unC\server\share\Desktop\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path
\\?\UNC\server\share\Desktop\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path
\\?\C:\Desktop\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path
\\?\C:\AbsoluteToRoot\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path
\\?\UNC\server\share\Desktop
\\?\UNC\\share\folder\Desktop
\\?\UNC\server\share

Ответ 2

Сегодня ваш счастливый день, потому что я просто работал над проблемой для своей собственной программы. Решение прост: Функция PathCchCanonicalizeEx добавит знак "\?", Если это необходимо. Но у этой функции есть несколько минусов, так как для Windows 8 требуется использовать целевую платформу, которая не является сделкой. Таким образом, я сделал свою собственную функцию, которая принимает "ненормальную" строку пути в качестве входа и выводит нормированную строку, готовую превышать предел MAX_PATH. Он использует новое определение в SDK Win8:

// max # of characters we support using the "\\?\" syntax
// (0x7FFF + 1 for NULL terminator)
#define PATHCCH_MAX_CCH             0x8000

Ниже перечислены объявления функций (а не для определения CString и использования аннотаций SAL):

//Normalize path and prepend "\\?\" if it exceeds the MAX_PATH limit
_Success_(return != false) //If the path was normalized and it exist (if bValidate == true) the return value is true and the normalized path is assigned to the sPath param
bool NormalizePath(_Inout_ CString & sPath, //Set to the abnormal path (relative, UNC, absolute), it is also used to store the normal path
    _In_ const CString sCurrentDir, //Set to the currend directory that will be used to resolve relative paths (used for security as GetCurrentDirectory function is thread-unsafe)
    _Out_opt_ bool *bDir = NULL, //Set to a bool pointer that will be set to true if the path points to a directory
    _In_ bool bValidate = false //If set the path existence is checked and the bDir argument is used
    );

И определения (без многих комментариев):

// max # of characters we support using the "\\?\" syntax
// (0x7FFF + 1 for NULL terminator)
#define PATHCCH_MAX_CCH             0x8000

#define LONG_PATH_ID                L"\\\\?\\"
#define UNC_PREFIX                  "\\\\"
#define UNC_LONG_ID                 L"\\\\?\\UNC\\"
#define CUR_DIR_REL_PATH_ID         ".\\"

#define WILDCAR_CHAR_ASTER          '*'
#define WILDCAR_CHAR_QUEMARK        '?'

#define DIR_DOWN                    ".."
#define DIR_UP                      "."

//Verify that a path exists and set bDir to true if the path points to an directory
bool ValidatePath(_In_ const TCHAR *sPath, _Out_ bool & bDir)
{
    //If the path contains a wildcards search test only the parent directory

    const TCHAR * sLastElement = _tcsrchr(sPath, _T('\\')); //The last component in the path

    bool bFoundWildCard = false;

    if(sLastElement)
    {
        ++sLastElement;
        if(_tcsrchr(sLastElement, _T(WILDCAR_CHAR_ASTER)) || _tcsrchr(sLastElement, _T(WILDCAR_CHAR_QUEMARK))) //If wilcard characters are contained in the last path component
        {
            bFoundWildCard = true;
            --sLastElement;
            const_cast<TCHAR *>(sLastElement)[0] = _T('\0');
        }
    }

    DWORD dwPathAttr = GetFileAttributes(sPath);

    if(dwPathAttr == INVALID_FILE_ATTRIBUTES)
    {
        _com_error sErrorMsg(GetLastError());
        //CProgramError.Set(sErrorMsg.ErrorMessage());
        return false;
    }

    bDir = dwPathAttr & FILE_ATTRIBUTE_DIRECTORY;

    if(bFoundWildCard)
    {
        const_cast<TCHAR *>(sLastElement)[0] = _T('\\');
    }

    return true;
}

void RespondPathComponent(_In_ const TCHAR *pComponent, _Out_ std::vector<CString> & vPathComponents)
{
    const TCHAR *pComponentLimiterR = _tcschr(pComponent, _T('\\'));

    const TCHAR *pComponentLimiterL = _tcschr(pComponent, _T('/'));

    const TCHAR *pComponentLimiter = NULL;

    if(pComponentLimiterR && pComponentLimiterL)
        pComponentLimiter = (pComponentLimiterR > pComponentLimiterL ? pComponentLimiterL : pComponentLimiterR);
    else
        pComponentLimiter = (pComponentLimiterR ? pComponentLimiterR : pComponentLimiterL);

    if(pComponentLimiter)
    {
        size_t szComponent = pComponentLimiter - pComponent;
        if(szComponent)
        {
            CString sTemp;
            sTemp.SetString(pComponent, szComponent);
            vPathComponents.push_back(sTemp);
        }
        ++pComponentLimiter;
        RespondPathComponent(pComponentLimiter, vPathComponents);
    }
    else
    {
        size_t szLastComp = _tcslen(pComponent);
        if(szLastComp)
        {
            CString sTemp;
            sTemp.SetString(pComponent, szLastComp);
            vPathComponents.push_back(sTemp);
        }
    }
}

size_t FixUpPathComponents(_Out_ std::vector<CString> & vPathComponents, _In_ const TCHAR *pPathComponents)
{
    RespondPathComponent(pPathComponents, vPathComponents);

    size_t szNumComponents = vPathComponents.size();

    for(size_t i(0); i < szNumComponents; ++i) //Check path components for special meanings
    {
        if(vPathComponents[i] == _T(DIR_DOWN))
        {
            vPathComponents.erase(vPathComponents.begin() + i); //Remove the current component
            --szNumComponents;
            if(i > 0)
            {
                vPathComponents.erase(vPathComponents.begin() + i - 1);
                --szNumComponents;
            }
        }
        else if(vPathComponents[i] == _T(DIR_UP))
        {
            if( (i + 1) < szNumComponents )
            {
                vPathComponents.erase(vPathComponents.begin() + i + 1);
                --szNumComponents;
            }
            vPathComponents.erase(vPathComponents.begin() + i); //Remove the current component
            --szNumComponents;
        }
    }

    return szNumComponents;
}

//Note that sCurrentDir is appended to all relative paths (nomatter the drive letter) - it needs to be a full path, not ending with '\\'
bool ExpandAndFixUpPath(_Inout_ CString & sPath, _In_opt_ const CString sCurrentDir)
{
    const size_t InPathStrSz = sPath.GetLength();

    if(!InPathStrSz) //Invalid path
        return false;

    //sPath.LockBuffer(); //Lock character buffer

    const TCHAR *PathBuffer = sPath.GetString(); //Retrieve the buffer

    if(InPathStrSz > 1) //To suppose the path is full it needs to have at lease 2 characters
    {
        if(_tcsstr(PathBuffer, _T(UNC_PREFIX)) == PathBuffer) //If the path begin with UNC_PREFIX
        {
            std::vector<CString> vPathComponents;

            size_t nComponents;

            if((nComponents = FixUpPathComponents(vPathComponents, &PathBuffer[2])) < 2) //A UNC path needs at leas two elements
                return false;

            sPath = _T('\\');

            for(size_t i(0); i < nComponents; ++i)
            {
                sPath += _T('\\');
                sPath += vPathComponents[i];
            }

            return true;
        }
        else if(PathBuffer[1] == _T(':')) //If the path begin with a disk designator
        {
            std::vector<CString> vPathComponents;

            if(FixUpPathComponents(vPathComponents, &PathBuffer[2]))
            {
                if(PathBuffer[2] == _T('\\') || PathBuffer[2] == _T('/'))
                {
                    sPath.SetString(PathBuffer, 2);

                    for(size_t i(0); i < vPathComponents.size(); ++i)
                    {
                        sPath += _T('\\');
                        sPath += vPathComponents[i];
                    }
                }
                else
                {
                    sPath = sCurrentDir;

                    for(size_t i(0); i < vPathComponents.size(); ++i)
                    {
                        sPath += _T('\\');
                        sPath += vPathComponents[i];
                    }
                }
            }
            else
            {
                sPath.SetString(PathBuffer, 2);
                sPath += _T('\\');
            }
            return true;
        }
    }

    std::vector<CString> vPathComponents;

    const TCHAR *pComponentsBegin = (_tcsstr(PathBuffer, _T(CUR_DIR_REL_PATH_ID)) == PathBuffer ? &PathBuffer[((sizeof(_T(CUR_DIR_REL_PATH_ID)) / sizeof(TCHAR)) - 1)] : PathBuffer);

    FixUpPathComponents(vPathComponents, pComponentsBegin);

    sPath = sCurrentDir;

    for(size_t i(0); i < vPathComponents.size(); ++i)
    {
        sPath += _T('\\');
        sPath += vPathComponents[i];
    }

    return true;
}

bool NormalizePath(_Inout_ CString & sPath, _In_ const CString sCurrentDir, _Out_opt_ bool *bDir = NULL, _In_ bool bValidate = false)
{
    if(!ExpandAndFixUpPath(sPath, sCurrentDir)) //Extend the path to it full form
        return false;

    size_t LongPathLen = sPath.GetLength();

    const TCHAR *pPathBuf = sPath.GetString();

#ifdef _UNICODE

    if(LongPathLen <= (MAX_PATH - 1)) //If the path is longer in the range of MAX_PATH return it directly
    {
        if(bValidate)
            if(!ValidatePath(pPathBuf, *bDir)) //Validate path before returning it
                return false;

        return true;
    }

    bool bIsUNCPath = _tcsstr(pPathBuf, _T(UNC_PREFIX)) == pPathBuf;

    if(!bIsUNCPath)
    {
        if(LongPathLen > (PATHCCH_MAX_CCH - 1 - ((sizeof(LONG_PATH_ID) / sizeof(WCHAR)) - 1))) //If have no space to store the prefix fail
        {
            //CProgramError.Set(_T("Path too long!"));
            return false;
        }


        CString sPathTmp = LONG_PATH_ID;

        sPathTmp += pPathBuf;

        if(bValidate)
            if(!ValidatePath(sPathTmp.GetString(), *bDir)) //Validate path before returning it
                return false;

        sPath = sPathTmp;

        return true;
    }
    else
    {
        if( LongPathLen > ( PATHCCH_MAX_CCH - 1 - ((sizeof(UNC_LONG_ID) / sizeof(WCHAR)) - 1) + ((sizeof(_T(UNC_PREFIX)) / sizeof(WCHAR)) - 1) ) ) //If have no space to store the prefix fail
        {
            //CProgramError.Set(_T("Path too long!"));
            return false;
        }


        CString sPathTmp = UNC_LONG_ID;

        sPathTmp += &pPathBuf[2];

        if(bValidate)
            if(!ValidatePath(sPathTmp.GetString(), *bDir)) //Validate path before returning it
                return false;

        sPath = sPathTmp;

        return true;
    }

#else

    if(bValidate)
        if(!ValidatePath(pPathBuf, *bDir)) //Validate path before returning it
            return false;

    return true;

#endif
}

Ответ 3

Вот пример, преобразованный в непроверенный код С++ из моего старого кода .NET.

#include <iostream>
#include <string>

// For PathIsRelative() & PathCombine()
#include "Shlwapi.h"
#pragma comment(lib, "Shlwapi.lib") 

// For _wgetcwd()
#include <direct.h>

std::wstring ConvertToWin32Path(std::wstring &filepath);
std::wstring MakePathAbsolute(std::wstring &filepath);

int main()
{
    std::wstring filepath;
    std::wcout << L"Enter absolute file path (ex. \"c:\\temp\\myfile.txt\"):";
    std::wcin >> filepath;
    std::wcout << L"Converted file path: " << ConvertToWin32Path(filepath);
    return 0;
}

// If file path is disk file path then prepend it with \\?\
// if file path is UNC prepend it with \\?\UNC\ and remove \\ prefix in unc path.
std::wstring ConvertToWin32Path(std::wstring &filepath)
{
    if (filepath.compare(0, 2, L"\\\\"))
    {
        // If the path is relative then we need to convert it to a absolute path
        if (PathIsRelative(filepath.c_str()))
            filepath = MakePathAbsolute(filepath);

        filepath = std::wstring(L"\\\\?\\") + filepath;
    }
    else 
    {
        // Is the path already converted, if so then return the same filepath
        if (filepath.compare(0, 3, L"\\\\?"))
            filepath = std::wstring(L"\\\\?\\UNC\\") + filepath.substr(2, filepath.length() - 2);
    }

    return filepath;    
}

// Converts a relative path to a absolute one by adding the path of the executable
std::wstring MakePathAbsolute(std::wstring &filepath)
{
    // Convert from a relative to an absolute file path
    const size_t maxCurrDirLen = 256;
    wchar_t currentDir[maxCurrDirLen];
    _wgetcwd(currentDir, maxCurrDirLen - 1);
    const size_t maxPathLen = 32767;
    wchar_t fullPath[maxPathLen];
    PathCombine(fullPath, currentDir, filepath.c_str());
    return std::wstring(fullPath);
}

Update:

Вы даже проверили мой код, прежде чем заключить, что

"Спасибо за попытку, но извините, это не так просто".

? Я добавил вывод из моего кода с новыми путями ввода сообщений; не могли бы вы указать, где мой код не работает? Насколько я вижу, мой код имеет более точный результат, чем ваш (более сложный код). Единственная проблема, которую я вижу, заключается в том, что путь UNC-обмена должен быть \\share\folder\Desktop, а не \\?\UNC\\share\folder\Desktop, но это простое исправление, но опять же ваш собственный код имеет ту же ошибку...

\\?\c:\dev\UNC_path_test
\\?\C:\Ba*d\P|a?t<h>\Windows\Folder
\\?\c:\dev\UNC_path_test\Relative\Folder\File.txt
\\?\C:\Windows\Folder
\\?\C:\Windows\Folder
\\?\UNC\server\share\Desktop
\\?\unC\server\share\Desktop\Very Long path\Very Long path\Very Long path\Very L
ong path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long p
ath\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\V
ery Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very L
ong path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long p
ath\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\V
ery Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very L
ong path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long p
ath\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\V
ery Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very L
ong path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long p
ath\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\V
ery Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very L
ong path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long p
ath\Very Long path\Very Long path\Very Long path
\\?\UNC\server\share\Desktop\Very Long path\Very Long path\Very Long path\Very L
ong path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long p
ath\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\V
ery Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very L
ong path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long p
ath\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\V
ery Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very L
ong path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long p
ath\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\V
ery Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very L
ong path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long p
ath\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\V
ery Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very L
ong path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long p
ath\Very Long path\Very Long path\Very Long path
\\?\C:\Desktop\Very Long path\Very Long path\Very Long path\Very Long path\Very
Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long
path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\
Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very
Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long
path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\
Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very
Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long
path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\
Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very
Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long
path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\
Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very
Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long
path\Very Long path\Very Long path
\\?\\AbsoluteToRoot\Very Long path\Very Long path\Very Long path\Very Long path\
Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very
Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long
path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\
Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very
Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long
path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\
Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very
Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long
path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\
Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very
Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long
path\Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\
Very Long path\Very Long path\Very Long path\Very Long path\Very Long path\Very
Long path\Very Long path\Very Long path
\\?\UNC\server\share\Desktop
\\?\UNC\\share\folder\Desktop
\\?\UNC\server\share