其中dwFlags正常应设为零,在结束时改为EVCCBF_LASTNOTIFICATION.ScanProgress函数的返回值很重要,因为用户可以在任何时候中断在进行中的清理任务。如ScanProgress返回E_ABORT,GetSpaceUsed应最快终端扫描,函数返回。因此,我们在递归的目录扫描函数ScanDir中,加入了如中断立即退出的功能。
HRESULT CCleanSimpleHandler::GetSpaceUsed (DWORDLONG *pdwSpaceUsed, IEmptyVolumeCacheCallBack *picb) { m_dwlFileSize = 0; ScanDir(m_strRootDir, picb); picb->ScanProgress(m_dwlFileSize, EVCCBF_LASTNOTIFICATION ,NULL); *pdwSpaceUsed = m_dwlFileSize; return S_OK; }
bool CCleanSimpleHandler::ScanDir(WCHAR * szDir, IEmptyVolumeCacheCallBack *pcib) { WCHAR strPath[MAX_PATH]; WCHAR* pchPathFileName; bool cancelled = false; WIN32_FIND_DATAW fd; HANDLE hFind;
if (cancelled = FAILED(pcib->ScanProgress(m_dwlFileSize, NULL, NULL))) return false; StrCpyW(strPath,szDir); PathAppendW(strPath, L"*"); pchPathFileName = strPath+lstrlenW(strPath)-1; hFind = FindFirstFileW(strPath, &fd); if (hFind == INVALID_HANDLE_VALUE) // E.g. Due to security issues return true; do { StrCpyW(pchPathFileName, fd.cFileName); if ((fd.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)) { if (fd.cFileName[0] != '.') { if (cancelled = !ScanDir(strPath, pcib)) break; } } else { WCHAR* pchExt = PathFindExtensionW(strPath); if ( StrCmpIW(pchExt, L".tmp") == 0 ) { m_dwlFileSize += ((DWORDLONG)fd.nFileSizeHigh)*4294967295+ fd.nFileSizeLow; WCHAR* filename = (WCHAR *)CoTaskMemAlloc((lstrlenW(strPath)+1)* sizeof(WCHAR)); StrCpyW(filename, strPath); m_lstFilesToDel.push_back(filename); } }
} while (FindNextFileW(hFind, &fd) != NULL); FindClose(hFind); return !cancelled; } |
其他的函数很简单。Purge函数将扫描出的文件列表m_lstFilesToDel中的文件一一删除。ShowProperties中,我们显示扫描出来的文件。最后,Deactivate将分配的内存释放。
HRESULT CCleanSimpleHandler::Purge (DWORDLONG dwSpaceToFree, IEmptyVolumeCacheCallBack *picb) { for (unsigned int i=0; i < m_lstFilesToDel.size(); ++i) DeleteFileW(m_lstFilesToDel[i]); return S_OK; }
HRESULT CCleanSimpleHandler::ShowProperties (HWND hWnd) { for (unsigned int i=0; i < m_lstFilesToDel.size(); ++i) if (MessageBoxW(hWnd, m_lstFilesToDel[i], L"View files", MB_OKCANCEL|MB_ICONINFORMATION)==IDCANCEL) break; return S_OK; }
HRESULT CCleanSimpleHandler::Deactivate (LPDWORD pdwFlags) { for (unsigned int i=0; i < m_lstFilesToDel.size(); ++i) CoTaskMemFree(m_lstFilesToDel[i]); m_lstFilesToDel.clear(); *pdwFlags = 0; return S_OK; |
结论和建议
通过实例分解,我们对Windows磁盘清理工具的基于COM技术的开发接口做了深入地研究。Windows外壳中有较多的开发接口,本文介绍的开发思想也可以运用在其它扩展插件中。
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【责编:John】