Script to merge values from a plist into another file

plistmerge.rb

#!/usr/bin/env ruby

if ARGV.size != 2
  puts "Merges Fields from Plist-Files together into a new file"
  puts "USAGE: ./plistmerge.rb source-file input-file"
  exit
end

# The values for those fields will be migrated from the source to the target file
FieldsToMigrate = %w(latitude longitude)

# Which field is used for matching dicts together
FieldToMatch    = 'id'

mapping       = {}

check_fileds  = [FieldToMatch] + FieldsToMigrate

source_file   = ARGV[0] # this file is the source
input_file    = ARGV[1] # this files values will be merged into the source
output_file   = source_file.gsub('.plist', '_new.plist')


# read the input file and build a hash with the data to be merged into the source file
#
node          = nil
attribute     = nil

File.open(input_file, "r:UTF-8") do |input|
  while (line = input.gets)
    
    if line =~ /<dict>/
      # start new node
      
      node = {}
      
    elsif line =~ /<\/dict>/
      # finish node
      
      id = node.delete(FieldToMatch)
      mapping[id], node = node, nil
      
    elsif attribute
      # read the value for the attribute, and reset the attribute
      
      node[attribute] = line[/<(integer|string|real|date)>(.+)<\/(integer|string|real|date)>/, 2]
      attribute = nil
      
    elsif at = line[/<key>(.+)<\/key>/, 1] and check_fileds.include?(at)
      # get the next key and set the attribute if we need it
      
      attribute = at
      
    end
    
  end
end



# Read the input file and write it into the output file dict by dict
# while updating the to be merged fields on the go
#

write_buffer  = []

File.open(output_file, "w:UTF-8") do |output|
  File.open(input_file, "r:UTF-8") do |source|
    while (line = source.gets)
      
      if line =~ /<dict>/
        # start new node
        
        write_buffer << line
        
      elsif line =~ /<\/dict>/
        # finish node
        
        write_buffer << line
        node      = nil
        
        attribute = nil
        write_buffer.each do |buffer_line|
          if at = buffer_line[/<key>(.+)<\/key>/, 1] and at == FieldToMatch
            attribute = FieldToMatch
          elsif attribute
            node      = buffer_line[/<(integer|string|real|date)>(.+)<\/(integer|string|real|date)>/, 2]
            attribute = nil
            break
          end
        end
        
        node = mapping[node]
        
        attribute = nil
        write_buffer.each do |buffer_line|
          if at = buffer_line[/<key>(.+)<\/key>/, 1] and FieldsToMigrate.include?(at)
            attribute = at
          elsif attribute
            buffer_line.gsub!(/<(integer|string|real|date)>(.+)<\/(integer|string|real|date)>/) do
              "<#{$1}>#{node[attribute]}</#{$3}>"
            end
            attribute = nil
          end
          
          output.puts buffer_line
        end
        write_buffer = []
        
      else
        
        write_buffer << line
        
      end
      
    end
  end
end