From: michael libby <x@...>
Date: 2002-09-23T12:37:47+09:00
Subject: Re: Getting a directory tree

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On Sunday 22 September 2002 16:34, dblack@candle.superlink.net wrote:
> On Mon, 23 Sep 2002, Hal E. Fulton wrote:
> > Here's one new version. It DOES NOT work, and I'm
> > not sure why yet.
> >
> >   def getdirs1(root)
> >     dirs=Dir.entries(root) - [".", ".."]
> >     temp = []
> >     dirs.each {|x| if test(?d,x) then temp << (root+SEP+x) end }
> >     list = [root] + temp
> >     dirs.each {|x| list += getdirs(x) }
> >     list
> >   end
> >
> > So my two questions are:
> >   1. What's wrong with getdirs1 that I'm not seeing?

The same problem David has below. The routine doesn't handle recursive 
directories well-- it follows the link back up the tree. You know that odd 
case where some malcontent has done:

ln -s ../.. link_up

In fact, I was surprised my test with David's routine below ever returned, 
but believe me... it was the ugliest nested list you ever saw. <grin />

> >   2. How would you write this in a reasonably
> >      efficient way?

Add a check for symlinks.

>   def getdirs_d1(root)
      return [] if File.lstat(root).symlink?

>     dirs=Dir.entries(root) - [".", ".."]
>     temp = dirs.map {|d| root+SEP+d}.select {|d| test(?d,d)}
>     temp + temp.map {|x| getdirs1(x) }
>   end

 -michael 

++++++++++++++++++++++++++++++++++++++++++
Michael C. Libby <x@ichimunki.com>
public key: http://www.ichimunki.com/public_key.txt
web site: http://www.ichimunki.com
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