From: cremes.devlist@...
Date: 2006-02-24T09:35:57+09:00
Subject: Nuby - help with Ruby object references

I'm very new to Ruby (as in, just started yesterday). As a learning  
exercise I decided to write a short program that would traverse a  
directory tree and take note of all duplicate files in that tree.

I'm using a hash of arrays to track all references. The key is the  
filename and I push the path as an array to store the value. If I run  
across a filename for which a key already exists in the hash, I do a  
deeper equality check to see if they are really the same file or if  
they are different. The "deeper check" is comparing file sizes.

If they are the same, I push this new path into my array of arrays so  
I can check against it if I find yet another file with that name. If  
they're different, I push this new path onto a SECOND hash of arrays.

This is where I have trouble. As soon as I push any value into this  
second hash, it takes on the identity of the first hash. I don't  
understand why because I am not doing any explicit operation to make  
hash1 = hash2. Maybe it's a side effect of some other operation.  
Anyway, enough talk... the code is below.

I appreciate any and all insight.

cr

--- code here ---

#!/usr/bin/env ruby

require 'find'

h = Hash.new { |h,k| h[k] = [] }
duplicates = Hash.new { |h,k| h[k] = [] }

working_path = ARGV[0] || ENV["PWD"]

Find.find(working_path) do |path|
   # if it's a dir, skip to the next path
   if File.directory?(path)
     next
   end
   file = File.basename(path)

   # if this key doesn't exist in the hash, add it
   if h.has_key?(file) == false
     h[file].push([path])
   else  # key already exists in hash
     # add file size to hash unless it was already grabbed
     h[file].push([path])
     h[file].each do |subarray|
       subarray[1] = File.size(subarray[0]) unless subarray[1]
     end

     # now compare the current file's size to the prior check
     h[file].each do |subarray|
       puts "subarray[0] = #{subarray[0]} and path = #{path}"
       if subarray[0].eql?(path) == false && subarray[1] == File.size 
(path)
         # add to dupe hash
         puts "DUPLICATE DUPLICATE DUPLICATE DUPLICATE"
         puts "DUP BEFORE h.id = #{h.object_id} and duplicates.id = # 
{duplicates.object_id}"
         duplicates[file].push([path]) # at this point "h" and  
"duplicates" refer to the same object!
         puts "DUP AFTER h.id = #{h.object_id} and duplicates.id = # 
{duplicates.object_id}"
       end
     end
   end
end

puts "\n\nThe duplicates are..."
duplicates.each do |key, value|
   puts "key = #{key}"
   value.each do |a|
     print "#{a[0]} #{a[1]} "
   end
   print "\n"
end