From: "Ara.T.Howard" <Ara.T.Howard@...>
Date: 2005-09-06T00:21:33+09:00
Subject: Re: Help me clean up this method

On Mon, 5 Sep 2005, Vincent Foley wrote:

> Hello guys,
>
> I wrote this little method to return the size of a given directory, but
> I think it's very ugly.  Could anyone help me clean it up a bit?
>
>
> def Dir.size(dirname)
>  Dir.chdir(dirname)
>  entries = Dir.entries(".").reject { |x| %w(. ..).include? x }
>  entries.collect! { |filename| File.expand_path(filename) }
>  size = 0
>  entries.each do |filename|
>    begin
>      if File.file?(filename)
>        size += File.size(filename) rescue 0
>      else
>        size += Dir.size(filename)
>      end
>    rescue
>      next
>    end
>  end
>  size
> end
>
> Thanks,
> Vincent.

just thought i'd point out that every solution posted thus far fails in a
variety of ways when links are considered - in the best cases linked files are
counted twice or linked dirs are not checked, in the worst case infinite loops
occur.  the methods using 'Dir[glob]' v.s. 'Find::find' suffer from the link
issue but also will perfom badly on large file systems.  unfortunately ruby's
built-in 'Find::find' cannot deal with links - for that you have to rely on
motoyuki kasahara's Find2 module, which you can get off of the raa.  i have it
inlined in my personal library (alib - also on the raa) with few small bug
fixes and interface additions, to use you would do something like:

   require 'alib'

   def dir_size dir
     size = 0
     totalled = {}
     ALib::Util::find2(dir, 'follow' => true) do |path, stat|
       begin
         next if totalled[stat.ino]
         next unless stat.file?
         size += stat.size
       ensure
         totalled[stat.ino] = true
       end
     end
     size
   end

   p dir_size('.')

this handles huge directories, duplicate files (links) in a directory, linked
directories, and potential infinite loops.  i think this is about as simply as
one can write this without introducing subtle, or not so subtle, bugs.

cheers.

-a
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