FtpFindFirstFile problem

Im writing my own little automatic FTP program that will backup web sites.  Im using the WinInet API.  I created a function which utilizes FtpFindFirstFile() & InternetFindNextFile().  This function gets called recursively whenever it find a subdirectory.  The biggest problem im having is when I try to traverse a directory tree using FtpFindFirstFile() & InternetFindNextFile().  When the code detects a subdirectory and I call my function recurses, I have to call FtpFindFirstFile() again inside of that recursive call.  In order for that to work, I needed to have closed the hFind in the calling function.  When the recursive function returns, I find myself having to call FtpFindFirstFile() again in the calling function in which it simply finds the same folder again.  An endless loop.  

I can't seem to figure a way around it.  Does anyone have any good code snippets or ideas for traversing a tree using WinInet FTP functions?

Thanks for the help,
-Dan  
dmaroffAsked:
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pThreadConnect With a Mentor Commented:
Try this code, I had the same problem and I fixed it with this.  I added in an STL list for you.

Good luck.


void BeginBackup(HANDLE& hConnect, char* remDir)
{
      DWORD size = MAX_PATH;
      
      WIN32_FIND_DATA remData;

      /* Files modification times */
      FILETIME locModified, a, b;
      
      /* Tests if file exists */
      HANDLE hFile;

      /* enumerates all files in a directory */
      HINTERNET hFind;

      /* Keeps track of paths used in directory searches */
      char fullPath[MAX_PATH];
      char parentDir[MAX_PATH];

      /* An STL list used to store enumerated directories */
      list <string> l;
      list <string>::iterator i;
      const char* path;
      
      /* Get the local working directory */
      GetCurrentDirectory(255, parentDir);
      
      /* Find the first file in a directory */
      hFind = FtpFindFirstFile(hConnect, NULL, &remData, NULL, NULL);


      /* If we locate a directory, add it to our list of
            directories that we will latere search */
      if(remData.dwFileAttributes == FILE_ATTRIBUTE_DIRECTORY) {
            
            /* Add directory to the list here */
            l.push_back(remData.cFileName);
      }

      /* Get the file if it doesn't exist or if file modified time is greater
         than the local file */
      else {
            sprintf(fullPath, "%s\\%s", parentDir, remData.cFileName);
            hFile = CreateFile(fullPath, GENERIC_READ , NULL, NULL, OPEN_EXISTING, NULL, NULL);
            
            if(GetFileTime(hFile, &a, &b, &locModified)) {      
                  if (CompareFileTime(&locModified, &remData.ftLastWriteTime) == -1) {
                        FtpGetFile(hConnect, remData.cFileName, remData.cFileName,
                        FALSE, NULL, FTP_TRANSFER_TYPE_BINARY , NULL);
                  }
            }
            else {
                        FtpGetFile(hConnect, remData.cFileName, remData.cFileName,
                                            FALSE, NULL, FTP_TRANSFER_TYPE_BINARY , NULL);
            }
            CloseHandle(hFile);
      }
            

      /* Search through the rest of the directory */
      while(InternetFindNextFile(hFind, &remData)) {
                        
            /* If we locate a directory, set it as current
            and search that directory using a recursive call */
            if(remData.dwFileAttributes == FILE_ATTRIBUTE_DIRECTORY) {
                  
                  /* Add directory to the list */
                  l.push_back(remData.cFileName);
            }
            /* If its a file, get it. */
            else {
                  sprintf(fullPath, "%s\\%s", parentDir, remData.cFileName);
                  hFile = CreateFile(fullPath, GENERIC_READ , NULL,
                                                       NULL, OPEN_EXISTING, NULL, NULL);
            
                  if(GetFileTime(hFile, &a, &b, &locModified)) {      
                        if (CompareFileTime(&locModified, &remData.ftLastWriteTime) == -1) {
                              FtpGetFile(hConnect, remData.cFileName, remData.cFileName,
                                                  FALSE, NULL, FTP_TRANSFER_TYPE_BINARY , NULL);
                        }
                  }
                  else {
                        FtpGetFile(hConnect, remData.cFileName, remData.cFileName,
                                                  FALSE, NULL, FTP_TRANSFER_TYPE_BINARY , NULL);
                  }
                  CloseHandle(hFile);
            }      

      }
      InternetCloseHandle(hFind);

      /* Traverse list of directories and dive into them */
      for(i = l.begin(); i != l.end(); ++i) {
            path = (*i).c_str();
            sprintf(fullPath, "%s\\%s", parentDir, path);
            
            if (!SetCurrentDirectory(fullPath)) {
                        CreateDirectory(fullPath, NULL);
                        SetCurrentDirectory(fullPath);
            }
            
            FtpSetCurrentDirectory(hConnect, path);
            BeginBackup(hConnect, (char*)path);
            FtpSetCurrentDirectory(hConnect, "..");
      }
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chensuCommented:
Look into the following sample. It uses MFC, but you can definitely get the idea.

FTPTREE: Displays the Structure and Content of an FTP Site
http://msdn.microsoft.com/isapi/msdnlib.idc?theURL=/library/devprods/vs6/visualc/vcsample/_sample_mfc_ftptree.htm
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dmaroffAuthor Commented:
I've seen this code already. The program is designed to be a bit different than mine.  The way that code works is it displays all of the files and folders in breadth order.  In other words it displays all of the files and folders in a root folder, then when you click a folder, it just does another search on that folder by issuing a FindFirstFile for that folder and so on.  

According to this code I'd have to keep a list of all the subfolders Ive seen in a given folder before I dive into one of those subfolders.  This way when I pop back up to that folder, I have a list of folders to go to without reissuing the search on that folder again.  


In other words if the tree looks like this:

\MainFolder
  - File1a
  - Folder1a
      - File1b
      - File2b
      - File3b
  - File2a
  - Folder2a
  - Folder3a

Id first use FindFirstFile() in Mainfolder which will traverse all of the files and folders of MainFolder.  As I do that, Id push all of the folders found (Folder1a, Folder2a, and Folder3a) onto a list.  

Once thats done I'd then dive into the first folder in my list (Folder1a), traverse that folder and when finished, pop back up to MainFolder.  At this point instead of doing a FindFirstFile() again, Id just go to the next folder in the list (Folder2a) and dive into that folder, and so on.  

This avoids having to use FindFirstFile() more than once on a folder, because each folder will have a list of its subfolders.   Thats the only way I can think of doing it.


Im trying to avoid that technique if possible.  If there is no way around it I guess I'll have to do that.  If you know another way that would be great.


Thanks,
-Dan
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xLsCommented:
maybe this will give you an idea

this is just some semipseudo code for doing your list recursivly.

int ListFiles(char* root,filelist* list)
{

   SFILE filestruct;
   DFile data;
   int count = 0;
   FindFirstFile(root,filestruct);
   while(FindNextFile(filestruct,data))
   {
      if(data.type == DIRECTORY)
       count =+ListFiles(data.name,list);
     else
        {
       list.insert(data);
        count++;
        }
   }

 return count;
}


no idea if you want it that way, but could be useful :)

cheers
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dmaroffAuthor Commented:
Thanks, as a matter of fact I did finish it.  I used an STL list which came in real handy.  I pretty much did it the same way you did.
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dmaroffAuthor Commented:
Thanks, even though I finished it you did give me a few new ideas.

-Dan
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xLsCommented:
just as a tip, try use vector<string> instead of list (list tends to have some allocation problems among other). you will not need to change your code that way anyway.
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dmaroffAuthor Commented:
Ok, I'll do that.

Thanks,
-Dan
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