Deep Space (was: The Directory Walker revisited)

[David Vaughan]

On Monday, Sep 8, 2003, at 23:18 Australia/Brisbane, David Vaughan 
<dvk at dvkconsult.com.au> wrote:
>
> Hmm. I have now encountered the same problem. As I wrote before, I had 
> no difficulty with 100,000 files and directories 17 deep, but the same 
> folders examined from their parent (the volume name) lead to a far 
> higher depth count (should have been only 18)
snip
>
> The alternative might be some trigger into circularity, which is what 
> happened with permissions.

Found it folks!

On OS X systems the folder //Network contains a reference to the local 
computer, which is where you started, so round you go again.

I made a specific adjustment at the beginning of the handler, thus:

    function walkDir dirPath
      if dirPath contains "//Network" then
        return empty
      end if
  -- etc as before

Running this worked across the entire root volume, returning over 
230,000 files in a 24MB list (maxDepth 18 as expected), no problems.

The same circularity will equally affect an iterative routine, not only 
a recursive approach, so whatever you do you need to protect against 
the specific problem or simply not allow a user to walk from root. The 
point of this exercise was to confirm that stack size did not limit a 
recursive approach.

Note also WA's apparent problem with an X11 sub-folder, although 
aliases did not appear to have added any circularity in my testing. Any 
routine should also be tested specifically on a Linux or Windows 
platform if it will be deployed there. The testing code comprises 
displaying the current path every time you hit a new maxDepth.

regards
David