Finding all empty directories in a subversion checkout

Ruby
1

Content preview: Hi, I tried to write a script to find all empty
directories
in a subversion checkout. In my view there were two main problems to
solve:
1) empty directories also contain .svn control directories […]

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Hi,

I tried to write a script to find all empty directories in a subversion
checkout. In my view there were two main problems to solve:

  1. empty directories also contain .svn control directories

  2. directories containing only further empty directories should be
    detected as such too.

I came up with Find all empty directories in an svn checkout · GitHub and on my simple tests so
far it worked well. I’d like to get feedback on the code and how I used
certain idioms, or rather, miss-used certain idioms or areas where I can
improve it “the ruby way”.

For example, I’m not really fond of the big case statement in the fourth
loop block:

dirs_count[dir] =
    Dir.entries(dir).collect { |e|
        case e
        when '.svn'
            nil
        when '.'
            nil
        when '..'
            nil
        else
            e
        end
    }.compact.count

Seems pretty redundant to me, in other languages I’d have written e.g.

switch(e) {
case ‘.svn’:
case ‘.’:
case ‘…’:
return nil;
default:
return e;
}

But I’m not sure how to apply that in ruby and I also think that these
could be improved anyway.

I’m sure a trained mind can spot other areas for improvement, I’m glad
for any suggestions!

thanks,

  • Markus
2

2011/3/3 Markus F. [email protected]:

   e
 end

}.compact.count
case … is the same as follows.
case e
when ‘.svn’, ‘.’, ‘…’
nil
else
e
end

Haruka YAGNI
[email protected]

3

On Thu, Mar 3, 2011 at 12:15 AM, Markus F. [email protected]
wrote:

           e
       end
   }.compact.count

Instead of mapping values to nil and using compact, you can simply use
Enumerable#reject or #select. For this, though, since I think you can
rely
on Dir.entries(dir).sort having “.” and “…” as the first two entries,
you
could get away with this:

Dir.entries(dir)[2…-1].reject { |e| e == “.svn” }

4

On Thu, Mar 3, 2011 at 1:03 AM, Adam P. [email protected]
wrote:

Dir.entries(dir)[2…-1].reject { |e| e == “.svn” }

And of course I forgot the .sort :slight_smile:

Dir.entries(dir).sort[2…-1].reject { |e| e == “.svn” }

5

On Mar 3, 2011, at 2:05 AM, Adam P. wrote:

On Thu, Mar 3, 2011 at 1:03 AM, Adam P. [email protected] wrote:

Dir.entries(dir)[2…-1].reject { |e| e == “.svn” }

And of course I forgot the .sort :slight_smile:

Dir.entries(dir).sort[2…-1].reject { |e| e == “.svn” }

2…-1 is not correct. It’s mostly correct, but what if valid files with
name.ord < “.”.ord (String#ord ruby19) exists?
p.e.

[sz@suessapfel:/tmp/foo]$ irb
irb:0> FileUtils.touch ‘-r’
=> [“-r”]
irb:0> Dir.entries(“.”).sort[-1…2]
=> [“…”]
irb:0> ^D[sz@suessapfel:/tmp/foo]$ l
total 0
-rw------- 1 sz wheel 0B Mar 3 15:30 -r
drwx------ 3 sz wheel 102B Mar 3 15:30 ./
drwxrwxrwt@ 11 root wheel 374B Mar 3 15:30 …/

All the best, Sandor Szcs