clone svn:externals

git-svn-externals.rb

#!/usr/bin/env ruby
#
# Inspired by https://github.com/andrep/git-svn-clone-externals
#
# MIT License http://koshigoe.mit-license.org
#

require 'fileutils'

module Git
  class Svn
    CABINET = '.git_externals'
    
    def initialize
      @url ||= `git svn info | grep '^URL: ' | cut -d' ' -f2`.chomp
      @cwd = File.expand_path '.'
      
      unless system("grep -q '#{CABINET}/*' .git/info/exclude")
        open('.git/info/exclude', 'a') do |output|
          output.puts "\n#{CABINET}/*"
        end
      end
    end

    def clone_externals
      each_externals do |property|
        puts "clone: #{property[:path]}#{property[:name]}"
        checkout_to = "#{CABINET}/#{property[:path]}#{property[:name]}"
        link_to = "#{property[:path]}#{property[:name]}"
        next if File.exists?(checkout_to)
        begin
          FileUtils.mkdir_p File.dirname(checkout_to)
          if system("git svn clone #{revision(property[:source])} #{property[:source]} #{checkout_to}")
            FileUtils.ln_s File.expand_path(checkout_to), link_to, :force => true
            unless system("grep -q '#{link_to}' .git/info/exclude")
              open('.git/info/exclude', 'a') do |output|
                output.puts "\n#{link_to}"
              end
            end
          end
        rescue => e
          $stderr.puts e.inspect
        end
      end
    end

    def rebase_externals
      Dir["#{CABINET}/**/.git"].each do |path|
        Dir.chdir(File.dirname(path)) do
          puts "rebase: #{Dir.pwd}"
          system("git svn rebase")
        end
      end
    end

    def fetch_externals
      Dir["#{CABINET}/**/.git"].each do |path|
        Dir.chdir(File.dirname(path)) do
          puts "fetch: #{Dir.pwd}"
          system("git svn fetch")
        end
      end
    end

    protected
    
    def each_externals
      @_cursor = nil
      IO.popen('git svn show-externals') do |io|
        while line = io.gets
          line.chomp!
          if %r{\A# /(.+)\z} =~ line
            @_cursor = $1
          elsif @_cursor && line.size > 0
            yield parse_property(line)
          end
        end
      end
    end

    def parse_property(line)
      if %r|\A/#{@_cursor}([^\s]+) (.+)\z| =~ line
        source, name = $1, $2
        source, name = name, source if name.include? '/'
        if %r{\A(?:/|\.)} =~ source
          path = File.expand_path("#{@_cursor}#{source}").sub("#{@cwd}/", '')
          source = "#{@url}/#{path}"
        end
        {
          :path => @_cursor,
          :source => source,
          :name => name,
        }
      else
        raise ArgumentError, "Invalid property: #{line}"
      end
    end

    def revision(url)
      '-' + `LANG=C svn log -l1 #{url}|awk '{if(NR==2){ print $1 }}'`.chomp
    end
  end
end

unless File.exists? '.git'
  raise '.git not found.'
end

def help
  $stderr.puts <<EOF
usage: git-svn-externals <subcommand>

Available subcommands:
   clone
   rebase
   fetch
   help
EOF
  exit
end

case ARGV.first
when 'clone'
  Git::Svn.new.clone_externals
when 'rebase'
  Git::Svn.new.rebase_externals
when 'fetch'
  Git::Svn.new.fetch_externals
when 'help'
  help
else
  help
end