#!/usr/bin/ruby


# Wrapper around the information provided by 'otool -L'
# and the editing capabilities of 'install_name_tool'.
class Dylib
  
  def initialize(path)
    @path = path    
  end
  
  def libraries
    lines = %x[otool -arch all -L '#{@path}'].split("\n")
    libraries = lines.reject { |line| line =~ /:$/ }
    libraries.map! { |line| line.split[0] }
    libraries.uniq
  end
  
  def install_name
    %x[otool -D '#{@path}'].split("\n")[1]
  end
  
  def install_name=(name)
    system "install_name_tool", "-id", name, @path
  end
  
  def change_library(old_path, new_path)
    system "install_name_tool", "-change", old_path, new_path, @path
  end
  
end

if __FILE__ == $0 then
  
  # Command line tool to change a shared library prefix referenced 
  # in a library.
  
  require 'optparse'
  require 'ostruct'
  
  $config = config = OpenStruct.new
  config.verbose = false
  
  ARGV.options do |opts|
    opts.banner = "usage: #{File.basename(__FILE__)} [options] FILES"
    opts.on('--old PREFIX') { |config.old_prefix| }
    opts.on('--new PREFIX') { |config.new_prefix| }
    opts.on('-v', '--verbose') { config.verbose = true }
    opts.parse!
  end
  
  if not config.old_prefix or not config.old_prefix then
    $stderr.puts "Need old and new prefix"
    exit 1
  end
  
  def msg(msg)
    $stderr.puts msg if $config.verbose
  end
  
  old_re = /^#{config.old_prefix}/
  
  ARGV.each do |file|
    msg "Working on #{file}"
    d = Dylib.new(file)
    install_name = d.install_name
    if install_name =~ old_re  then
      new_install_name = install_name.sub(old_re) { config.new_prefix }
      msg " Changing install name from #{install_name} to #{new_install_name}"
      d.install_name = new_install_name
    end
      
    d.libraries.each do |library|
      if library =~ old_re then
        new_library = library.sub(old_re) { config.new_prefix }
        msg " Changing library ref from #{library} to #{new_library}"
        d.change_library(library, new_library)
      end
    end
  end
  
end