Why am I having problems recursively deleting directories?

Question

I've written an application that uses the WIN32 api to create a temporarily directory hierarchy. Now, when wanting to delete the directories when shutting down the application I'm running into some problems.

So lets say I have a directory hierarchy: C:\temp\directory\subdirectory\

I'm using this recursive function:

bool Dir::deleteDirectory(std::string& directoryname, int flags)
{
    if(directoryname.at(directoryname.size()-1) !=  '\\') directoryname += '\\';

    if ((flags & CONTENTS) == CONTENTS)
    {
        WIN32_FIND_DATAA fdata;
        HANDLE dhandle;

        directoryname += "\\*";
        dhandle = FindFirstFileA(directoryname.c_str(), &fdata);

        // Loop through all the files in the main directory and delete files & make a list of directories
        while(true)
        {
            if(FindNextFileA(dhandle, &fdata))
            {
                std::string filename = fdata.cFileName;
                if(filename.compare("..") != 0)
                {
                    std::string filelocation = directoryname.substr(0, directoryname.size()-2) + StringManip::reverseSlashes(filename);

                    // If we've encountered a directory then recall this function for that specific folder.
                    if(!isDirectory(filelocation))  DeleteFileA(filename.c_str());
                    else deleteDirectory(filelocation, DIRECTORY_AND_CONTENTS);
                }
            } else if(GetLastError() == ERROR_NO_MORE_FILES)    break;
        }
        directoryname = directoryname.substr(0, directoryname.size()-2);
    }

    if ((flags & DIRECTORY) == DIRECTORY)
    {
        HANDLE DirectoryHandle;
        DirectoryHandle = CreateFileA(directoryname.c_str(),
                                FILE_LIST_DIRECTORY,
                                FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
                                NULL,
                                OPEN_EXISTING,
                                FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OVERLAPPED,
                                NULL);
        bool DeletionResult = (RemoveDirectoryA(directoryname.c_str()) != 0)?true:false;
        CloseHandle(DirectoryHandle);
        return DeletionResult;
    }

     return true;
}

This function iterates over the directory contents of the temp directory; and for each directory in the temp directory it keeps recalling itself until it's at the lowest directory; subdirectory in the example.

There are also 3 flags defined

 enum DirectoryDeletion
 {
    CONTENTS = 0x1,
    DIRECTORY = 0x2,
    DIRECTORY_AND_CONTENTS = (0x1 | 0x2)
 };

When using this function, it only removes the lowest subdirectory and I can't remove the ones higher in hierarchy because it says that the directory is not empty. When I go and look to the directory 'subdirectory' is only removed after the application ends. However, when I try to encapsulate this in a non recursive simple main application I have no problems at all with deleting the directories.

Answer 1

There's a Windows API, SHFileOperation, that will do a recursive folder delete for you.

LONG DeleteDirectoryAndAllSubfolders(LPCWSTR wzDirectory)
{
    WCHAR szDir[MAX_PATH+1];  // +1 for the double null terminate
    SHFILEOPSTRUCTW fos = {0};

    StringCchCopy(szDir, MAX_PATH, wzDirectory);
    int len = lstrlenW(szDir);
    szDir[len+1] = 0; // double null terminate for SHFileOperation

    // delete the folder and everything inside
    fos.wFunc = FO_DELETE;
    fos.pFrom = szDir;
    fos.fFlags = FOF_NO_UI;
    return SHFileOperation( &fos );
}

Answer 2

You're not closing dhandle from all those FindFirstFile calls, so each directory has a reference to it when you try to delete it.

And, why do you need to create DirectoryHandle? It's not needed, and will probably also block the directory deletion.

When your app closes, those handles are forced close, and (I guess) the last attempted delete then succeeds.