【C/C++】一种同步目录的实现——No“删除整个目录再拷贝”

// 算法是：
// 遍历 dstDir，将所有 srcDir 中不存在的文件删除；
// 遍历 srcDir，若与 dstDir 目录中对应文件的修改日期不一致则替换该文件；
// 忽略 excludeFile 文件里指示的目录和文件。

struct IgnoreName
{
    bool    isDir;
    tchar    fileName[MAX_PATH];
};

bool GetIgnoreNames(const char* excludeFile, std::vector<IgnoreName>& ignoreNames)
{
    bool result = true;
    ignoreNames.clear();
    if (excludeFile)
    {
        FILE* fp = NULL;
        if (_tfopen_s(&fp, Utf8ToTStr(excludeFile).c_str(), _T("rt")) == 0)
        {
            char line[MAX_PATH] = {0};
            while (fgets(line, MAX_PATH, fp))
            {
                size_t len = strlen(line);
                if (line[len - 1] == _T('\n'))
                {
                    line[len - 1] = '\0';
                }

                IgnoreName ignore = {0};
                tstring fileName = Utf8ToTStr(line);
                ignore.isDir = (fileName[0] == _T('\\'));
                if (ignore.isDir)
                {
                    fileName = GetFileName(fileName);
                }
                _tcscpy_s(ignore.fileName, MAX_PATH, fileName.c_str());
                ignoreNames.push_back(ignore);
            }
            fclose(fp);
        }
        else
        {
            g_logHelper.OutputErrorInfo(_T("GetIgnoreNames 打开文件(%s)失败！"), Utf8ToTStr(excludeFile).c_str());
            result = false;
        }
    }

    return result;
}

bool IsIgnoreFile(WIN32_FIND_DATA& findData, const std::vector<IgnoreName>& ignoreNames)
{
    bool isDir = ((findData.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) != 0);
    std::vector<IgnoreName>::const_iterator it = ignoreNames.begin();
    for (; it != ignoreNames.end(); ++it)
    {
        if (isDir == it->isDir && _tcsicmp(findData.cFileName, it->fileName) == 0)
        {
            return true;
        }
    }
    
    return false;
}

bool DeleteDirRecursively(tstring dirPath)
{
    bool result = true;
    WIN32_FIND_DATA finddata;
    HANDLE hfind = FindFirstFile(JoinPath(dirPath, _T("*.*")).c_str(), &finddata);
    if (hfind == INVALID_HANDLE_VALUE)
    {
        return result;
    }

    do 
    {
        tstring path = JoinPath(dirPath, finddata.cFileName);
        if (_tcscmp(finddata.cFileName, _T(".")) == 0 || _tcscmp(finddata.cFileName, _T("..")) == 0)
        {
            continue;
        }
        if(finddata.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
        {
            if (! DeleteDirRecursively(path))
            {
                result = false;
            }            
        }
        else
        {
            if (_tremove(path.c_str()) != 0)
            {
                g_logHelper.OutputErrorInfo(_T("DeleteDirRecursively 删除文件(%s)失败！"), path.c_str());
                result = false;
            }            
        }
    } while (FindNextFile(hfind, &finddata) != FALSE && result);
    FindClose(hfind);

    if (result && _trmdir(dirPath.c_str()) != 0)
    {
        g_logHelper.OutputErrorInfo(_T("DeleteDirRecursively 删除目录(%s)失败！"), dirPath.c_str());
        result = false;
    }

    return result;
}

// 删除dstDir中多余的文件
bool DeleteUnnecessaryFileInDst(tstring srcDir, tstring dstDir, const std::vector<IgnoreName>& ignoreNames)
{
    bool result = true;
    WIN32_FIND_DATA findData;
    HANDLE dstFindHandle = FindFirstFile(JoinPath(dstDir, _T("*.*")).c_str(), &findData);
    if (dstFindHandle != INVALID_HANDLE_VALUE)
    {
        do 
        {
            if (_tcscmp(findData.cFileName, _T(".")) == 0
                || _tcscmp(findData.cFileName, _T("..")) == 0
                || IsIgnoreFile(findData, ignoreNames))
            {
                continue;
            }
            tstring srcPath = JoinPath(srcDir, findData.cFileName);
            tstring dstPath = JoinPath(dstDir, findData.cFileName);
            if (! FileExists(srcPath))
            {    // 删除dstDir目录中的该文件
                if (findData.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
                {
                    result = DeleteDirRecursively(dstPath);
                }
                else
                {
                    result = (_tremove(dstPath.c_str()) == 0);
                    if (! result)
                    {
                        g_logHelper.OutputErrorInfo(_T("DeleteUnnecessaryFileInDst 删除文件(%s)失败！"), dstPath.c_str());
                    }
                }
            }
            
            if (result && (findData.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) != 0)
            {
                result = DeleteUnnecessaryFileInDst(srcPath, dstPath, ignoreNames);
            }
        } while (FindNextFile(dstFindHandle, &findData) != FALSE && result);
        FindClose(dstFindHandle);
    }

    return result;
}

bool IsSame(WIN32_FIND_DATA& srcData, WIN32_FIND_DATA& dstData)
{
    // todo! 判断两个文件是否一致，为了高效，目前仅使用文件修改时间的判断
    bool result = (srcData.ftLastWriteTime.dwHighDateTime == dstData.ftLastWriteTime.dwHighDateTime);
    if (result)
    {
        result = (srcData.ftLastWriteTime.dwLowDateTime == dstData.ftLastWriteTime.dwLowDateTime);
    }

    return result;
}

// 将dstDir中与srcDir中不一致的文件替换为srcDir中对应的文件
bool SyncDir(tstring srcDir, tstring dstDir, const std::vector<IgnoreName>& ignoreNames)
{
    bool result = true;

    WIN32_FIND_DATA findData;
    HANDLE srcFindHandle = FindFirstFile(JoinPath(srcDir, _T("*.*")).c_str(), &findData);
    if (srcFindHandle != INVALID_HANDLE_VALUE)
    {
        do 
        {
            if (_tcscmp(findData.cFileName, _T(".")) == 0
                || _tcscmp(findData.cFileName, _T("..")) == 0
                || IsIgnoreFile(findData, ignoreNames))
            {
                continue;
            }
            tstring srcPath = JoinPath(srcDir, findData.cFileName);
            tstring dstPath = JoinPath(dstDir, findData.cFileName);

            bool shouldCopy = false;
            WIN32_FIND_DATA dstData;
            HANDLE dstFindHandle = FindFirstFile(dstPath.c_str(), &dstData);
            if (dstFindHandle != INVALID_HANDLE_VALUE)
            {
                if ((dstData.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) != (findData.dwFileAttributes&FILE_ATTRIBUTE_DIRECTORY))
                {
                    if (dstData.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
                    {
                        result = DeleteDirRecursively(dstPath);
                    }
                    else
                    {
                        result = _tremove(dstPath.c_str()) == 0;
                        if (! result)
                        {
                            g_logHelper.OutputErrorInfo(_T("SyncDir 删除文件(%s)失败"), dstPath.c_str());
                        }
                    }
                    shouldCopy = true;
                }
                else if ((dstData.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) == 0 && !IsSame(findData, dstData))
                {
                    shouldCopy = true;
                    result = _tremove(dstPath.c_str()) == 0;
                    if (! result)
                    {
                        g_logHelper.OutputErrorInfo(_T("SyncDir 删除文件(%s)失败"), dstPath.c_str());
                    }
                }
                FindClose(dstFindHandle);
            }
            else    // dstPath对应文件或者目录不存在
            {
                shouldCopy = true;
            }

            if (result && shouldCopy)
            {
                if (findData.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
                {
                    result = _tmkdir(dstPath.c_str()) == 0;
                    if (! result)
                    {
                        g_logHelper.OutputErrorInfo(_T("SyncDir 创建目录(%s)失败"), dstPath.c_str());
                    }
                }
                else
                {
                    result = ::CopyFile(srcPath.c_str(), dstPath.c_str(), TRUE) != FALSE;
                    if (! result)
                    {
                        g_logHelper.OutputErrorInfo(_T("SyncDir 复制文件(%s)到(%s)失败"), srcPath.c_str(), dstPath.c_str());
                    }
                }
            }

            if (result && findData.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
            {
                result = SyncDir(srcPath, dstPath, ignoreNames);
            }
        } while (FindNextFile(srcFindHandle, &findData) != FALSE && result);
        FindClose(srcFindHandle);
    }

    return result;
}

bool RestoreDir(const char* srcDir, const char* dstDir, const char* excludeFile/* = NULL*/)
{
    std::vector<IgnoreName> ignoreNames;
    if (! GetIgnoreNames(excludeFile, ignoreNames))
    {
        return false;
    }
    
    bool result = DeleteUnnecessaryFileInDst(Utf8ToTStr(srcDir), Utf8ToTStr(dstDir), ignoreNames);
    if (result)
    {
        result = SyncDir(Utf8ToTStr(srcDir), Utf8ToTStr(dstDir), ignoreNames);
    }

    return result;
}