configure

#!/usr/bin/env ruby

if ENV["RUBYLIB"]
  STDERR.puts "ERROR: Please unset RUBYLIB to configure Rubinius"
  exit 1
end

require 'rbconfig'
require 'tempfile'
require 'fileutils'

root = File.expand_path File.dirname(__FILE__)

require File.join(root, "kernel", "delta", "options")

class Configure

  def initialize(root)
    @log = Logger.new "configure.log"

    @defines = []
    @config = File.join(root, "config.rb")

    # TODO: conditionalize for Windows
    @host = `./rakelib/config.guess`.chomp
    /([^-]+)-([^-]+)-(.*)/ =~ @host
    @cpu, @vendor, @os = $1, $2, $3
    @little_endian = false
    @sizeof_long = 0

    # Compiler / build settings
    @cc = ENV['CC'] || 'gcc'
    @cxx = ENV['CXX'] || 'g++'
    @rake = ENV['RAKE'] || 'rake'
    @install = false
    @build_ruby = nil

    # LLVM settings
    @use_llvm               = true
    @llvm                   = :no
    @llvm_path              = nil
    @llvm_configure         = nil
    @llvm_skip_system       = false
    @llvm_skip_prebuilt     = false
    @llvm_prebuilt_name     = nil
    @llvm_system_name       = get_system_name

    @llvm_version           = "2.8"
    @llvm_source            = "llvm-2.8.tgz"
    @llvm_source_dir        = "llvm-2.8"
    @llvm_source_url        = "http://llvm.org/releases/2.8/llvm-2.8.tgz"
    @llvm_asset_path        = "http://asset.rubini.us/prebuilt"

    @gcc_major = `#{@cc} -dumpversion`.strip.split(".")[0,2].join(".")

    if @host == "i686-pc-linux-gnu" || @host == "x86_64-unknown-linux-gnu"
      @llvm_generic_prebuilt  = "llvm-#{@llvm_version}-#{@host}-#{@gcc_major}.tar.bz2"
    else
      @llvm_generic_prebuilt  = "llvm-#{@llvm_version}-#{@host}.tar.bz2"
    end

    @llvm_parent_path       = File.join(root, "vm", "external_libs")
    @llvm_default           = File.join(@llvm_parent_path, "llvm")
    @llvm_prebuilt_path     = File.join(@llvm_parent_path, "prebuilt")
    @llvm_include_path      = File.join(@llvm_default, "include")

    # File system paths
    @bindir       = root + "/bin"
    @includedir   = root + "/vm/capi/include"
    @libdir       = root
    @runtime      = @libdir + "/runtime"
    @lib_path     = @libdir + "/lib"
    @ext_path     = @libdir + "/lib/ext"
    @mandir       = root + "/man"
    @gemsdir      = root + "/gems"

    # Some simple defaults for when running directly out of the build dir
    @sitedir      = @lib_path + "/site"
    @vendordir    = @lib_path + "/vendor"

    @program_name = "rbx"

    # Library configuration
    @rb_readline = false

    # Essential settings (modify these for creating releases)
    @libversion = "1.1"
    @version = "#{@libversion}.1"
    @release_date = "2010-11-16"
    @config_version = 25

    if !ENV['RELEASE'] and File.directory?(root + "/.git")
      @buildrev = `git rev-list --all | head -n1`.chomp
    else
      @buildrev = "release"
    end

    # TODO: add conditionals for platforms
    if RbConfig::CONFIG["build_os"] =~ /darwin/
      @ldshared = "cc -dynamic -bundle -undefined suppress -flat_namespace"
    else
      @ldshared = "cc -shared"
    end
  end

  def expand(path)
    File.expand_path(path)
  end

  def options
    o = Rubinius::Options.new "Usage: configure [options]", 30
    o.left_align

    o.doc " Configure settings"

    o.on "--log-file", "NAME", "Write log to file NAME" do |name|
      old_log = @log.path
      @log = Logger.new name, false
      @log.replace old_log
    end

    o.on "--rake", "NAME", "Use NAME as 'rake' during build" do |name|
      @rake = name
    end

    o.doc "\n Compiler settings"

    o.on "--cc", "COMPILER", "Compiler to use for C code (eg gcc, clang)" do |cc|
      @cc = cc
    end

    o.on "--cxx", "COMPILER", "Compiler to use for C++ code (eg g++, clang++)" do |cxx|
      @cxx = cxx
    end

    o.doc "\n LLVM settings"

    o.on "--disable-llvm", "Don't build with LLVM" do
      @use_llvm = false
    end

    o.on "--enable-llvm", "Enable llvm (default)" do
      @use_llvm = true
    end

    o.on "--skip-system", "Don't consider a system LLVM installation" do
      @llvm_skip_system = true
    end

    o.on "--skip-prebuilt", "Don't try to use a prebuilt version of LLVM" do
      @llvm_skip_prebuilt = true
    end

    o.on "--system-name", "NAME", "Name of OS (eg fedora-8, ubuntu-10.04)" do |name|
      @llvm_system_name = name
    end

    o.on "--prebuilt-name", "NAME", "Full name of LLVM prebuilt archive" do |name|
      @llvm_prebuilt_name = name
    end

    o.on "--llvm-path", "PATH", "File system path to the directory containing LLVM" do |dir|
      @llvm_path = dir
    end

    o.on "--update-prebuilt", "Update prebuilt LLVM packages from the internet" do
      update_prebuilt @llvm_generic_prebuilt, true
    end

    o.doc "\n File system paths for installing Rubinius"

    o.on "-P", "--prefix", "PATH", "Install Rubinius in subdirectories of PATH" do |dir|
      @install = true
      dir = File.expand_path dir

      if !ENV['RELEASE'] and File.directory? dir and dir !~ /(rubinius|rbx).*\/?$/
        old = dir
        dir += "/rubinius/#{@libversion}"
        @log.write "The directory #{old} already exists, installing to #{dir}"
      end

      @bindir       = dir + "/bin"
      @includedir   = dir + "/include"
      @libdir       = dir
      @runtime      = @libdir + "/runtime"
      @lib_path     = @libdir + "/lib"
      @ext_path     = @libdir + "/lib/ext"
      @mandir       = dir + "/man"
      @gemsdir      = dir + "/gems"

      @sitedir      = dir + "/site"
      @vendordir    = dir + "/vendor"
    end

    o.on "-B", "--bindir", "PATH", "Install Rubinius executable in PATH" do |dir|
      @install = true
      @bindir = expand dir
    end

    o.on "-I", "--includedir", "PATH", "Install Rubinius C-API include files in PATH" do |dir|
      @install = true
      @includedir = expand dir
    end

    o.on "-L", "--libdir", "PATH", "Install Ruby library in PATH" do |dir|
      @install = true
      @libdir   = expand(dir) + "/rubinius/#{@libversion}"
      @runtime  = @libdir + "/runtime"
      @lib_path = @libdir + "/lib"
      @ext_path = @libdir + "/lib/ext"

      @sitedir   = @libdir + "/site"
      @vendordir = @libdir + "/vendor"
    end

    o.on "-M", "--mandir", "PATH", "Install man pages in PATH" do |dir|
      @install = true
      @mandir = expand dir
    end

    o.on "-G", "--gemsdir", "PATH", "Install gems in PATH" do |dir|
      @install = true
      @gemsdir = expand dir
    end

    o.on "--sitedir", "PATH", "Install site-specific Ruby code in PATH" do |dir|
      @install = true
      @sitedir = expand dir
    end

    o.on "--vendordir", "PATH", "Install vendor-specific Ruby code in PATH" do |dir|
      @install = true
      @vendordir = expand dir
    end

    o.doc "\n Optional features"

    @options = o

    @features = {}

    default_on = RUBY_PLATFORM !~ /openbsd/i
    feature "execinfo", default_on
    feature "C-readline", true
    feature "ruby-readline", false

    o.doc "\n Help!"

    o.on "--show", "Print the current configuration and exit" do
      print_debug
      exit 0
    end

    o.on "-V", "--verbose", "Print additional info" do
      @verbose = true
    end

    o.help

    o.doc ""

  end

  def feature(name, on_by_default=true)
    @features[name] = on_by_default

    @options.on "--with-#{name}", "Enable #{name}" do
      @features[name] = true
    end

    @options.on "--without-#{name}", "Disable #{name}" do
      @features[name] = false
    end
  end

  def parse(ary)
    @options.parse ary
  end

  require 'digest/md5'

  def md5_checksum(md5_path, full_path)
    md5 = Digest::MD5.new

    File.open full_path do |file|
      until file.eof?
        md5 << file.read(1024)
      end
    end

    return md5.hexdigest == File.read(md5_path).strip.split(" ").first
  end

  require 'net/http'

  def download(url, full_path)
    begin

     if ENV['http_proxy']
        protocol, userinfo, host, port  = URI::split(ENV['http_proxy'])
        proxy_user, proxy_pass = userinfo.split(/:/) if userinfo
        http = Net::HTTP::Proxy(host, port, proxy_user, proxy_pass)
      else
        http = Net::HTTP
      end

      @log.write "    Downloading #{File.basename(full_path)}..."
      http.get_response(URI(url)) do |res|
        case res
        when Net::HTTPNotFound
          @log.write "      Not found."
          return false
        when Net::HTTPClientError
          @log.write "      ERROR: #{res.inspect}"
          return false
        end

        size = 0
        total = res.header['Content-Length'].to_i

        File.open full_path, "w" do |f|
          res.read_body do |chunk|
            f << chunk
            size += chunk.size
            print "\r      [ %d%% (%d of %d) ]" % [(size * 100) / total, size, total]
          end
        end
        @log.write ": done!"
      end
    rescue Exception => e
      File.unlink full_path if File.exists?(full_path)
      @log.write " ERROR: #{e.message}"
      return false
    end

    return true
  end

  # Downloads a pre-built LLVM library for a platform if the file exists.  If
  # an MD5 checksum file exists for the library, the checksum of the library
  # is compared and the update fails if it does not match.  If no MD5 checksum
  # file exists, the library is used without check.
  def update_prebuilt(file, warn)
    full_path = File.join @llvm_prebuilt_path, file
    md5_path = "#{full_path}.md5"

    dir = File.dirname full_path

    Dir.mkdir dir unless File.exists? dir

    url = File.join @llvm_asset_path, file

    unless File.exists? full_path
      download url, full_path

      unless File.exists? full_path
        @log.write "ERROR. No #{file} available on server." if warn
        return false
      end
    end

    md5_url = "#{url}.md5"
    download md5_url, md5_path

    if File.exists? md5_path
      unless md5_checksum md5_path, full_path
        @log.write "ERROR. #{file} was corrupted or MD5 checksum is outdated."
        return false
      else
        @log.write "    MD5 checksum for prebuilt LLVM verified."
      end
    else
      @log.write "   No MD5 checksum for #{file} available on server."
      @log.write "   Using LLVM library without checksum validation."
    end

    @log.write "    Prebuilt packages updated."
  end

  def setup_source
    url = @llvm_source_url
    path = File.join @llvm_prebuilt_path, @llvm_source

    unless File.exists?(path)
      @log.write "  Downloading #{url}..."
      return false unless download(url, path)
    end

    if File.exists?(path)
      @log.print "  Unpacking LLVM source: "
      system "cd #{@llvm_parent_path}; tar xzf #{path}; mv #{@llvm_source_dir} llvm"
      @log.write "done!"

      if File.exists?(@llvm_include_path)
        @log.write "  Code appears to be a proper tree."
      else
        @log.write "  Code doesn't appear to be proper LLVM tree!"
        return false
      end

      @llvm = :svn
      return true
    end

  end

  def prebuilt_files
    files = [@llvm_generic_prebuilt]

    # If we have a system name, try to find a prebuilt specifically
    # for this system first.
    if @llvm_system_name
      files.unshift "llvm-#{@llvm_version}-#{@host}-#{@llvm_system_name}.tar.bz2"
    end

    # Try one for just the darwin major version (which increases for each
    # minor OS X version. ie. 10.5 == 9.x.x, 10.6 == 10.x.x)
    if m = /darwin(\d+)\.(\d+)\.(\d+)/.match(@os)
      # Try this last
      files.push "llvm-#{@llvm_version}-#{@cpu}-#{@vendor}-darwin#{m[1]}.tar.bz2"
    end

    # If the user specified a name, try that before anything.
    files.unshift @llvm_prebuilt_name if @llvm_prebuilt_name

    files
  end

  def setup_prebuilt
    @log.write "  Checking for prebuilt LLVM package..."

    prebuilt_files.each do |file|
      path = File.join @llvm_prebuilt_path, file

      update_prebuilt file, false unless File.exists?(path)

      if File.exists?(path)
        @log.print "  Unpacking prebuilt LLVM: #{file}: "
        system "cd #{@llvm_parent_path}; mkdir llvm; cd llvm; tar xjf #{path}"
        @log.write "done!"
        @llvm = :prebuilt
        return true
      end
    end

    @log.write "  Unable to download any LLVM prebuilt"
    return false
  end

  def setup_path
    @log.print "Validating '#{@llvm_path}': "
    if File.directory? @llvm_path
      ["Release", "Debug"].each do |which|
        sub = File.join(@llvm_path, which, "bin")
        if File.directory? sub
          @log.write "Ok! Using #{which}"
          @llvm_configure = File.join(@llvm_path, which, "bin", "llvm-config")
          @llvm = :config
          return true
        end
      end

      @log.write "ERROR. Doesn't appear to be built already!"
      return false
    end

    @log.write "ERROR. Path doesn't exist."
    return false
  end

  def setup_auto
    @log.print "  Checking for existing LLVM tree: "
    if File.directory?(@llvm_default)
      version = `#{@llvm_default}/Release/bin/llvm-config --version`.strip
      if version == "2.8"
        @log.write "found!"
        if File.exists?(File.join(@llvm_default, "Makefile.common"))
          @llvm = :svn
        else
          @llvm = :prebuilt
        end

        return
      else
        @log.write "outdated (version #{version})"

        if File.exists?(File.join(@llvm_default, "Makefile.common"))
          @log.error "ABORT: Unwilling to override custom LLVM tree, please update it manually"
          exit 1
        else
          @log.write "    Removing outdated tree..."
          FileUtils.rm_rf(@llvm_default)
        end
      end
    else
      @log.write "not found."
    end

    # If they explicitly said where LLVM is, use that and fail hard.
    if @llvm_path
      unless setup_path
        @log.error "ABORT: Path '#{@llvm_path}' not a proper LLVM path"
        exit 1
      end

      return
    end

    return if !@llvm_skip_system && setup_config
    return if !@llvm_skip_prebuilt && setup_prebuilt
    return if setup_source

    @log.write "WARNING: Unable to configure for LLVM, disabling support."
    @use_llvm = false
  end

  def setup_config
    @log.print "  Checking for 'llvm-config': "
    which = ENV['PATH'].split(":").find do |path|
      File.exists? File.join(path, "llvm-config")
    end

    if which
      config = File.join(which, "llvm-config")
      version = `#{config} --version`.strip
      parts = version.sub(/svn$/, "").split(".").map { |i| i.to_i }

      if parts[0] != 2 or parts[1] != 8
        @log.write "only 2.8 is supported"
      else
        @log.write "found! (version #{version})"
        @llvm_configure = config
        @llvm = :config
        return true
      end
    else
      @log.write "not found"
    end

    false
  end

  def c_includes
    str = []
    if File.exists? "/usr/local/include"
      str << "-I/usr/local/include"
    end

    if File.exists? "/opt/local/include"
      str << "-I/opt/local/include"
    end

    return str.join(" ")
  end

  def env(which)
    ENV[which] || ""
  end

  def check_program(run=true, link_libs=[])
    begin
      basename = "rbx-configure-test"
      source   = basename + ".cpp"
      File.open source, "w" do |f|
        yield f
      end

      if link_libs.empty?
        libs = ""
      else
        libs = link_libs.map { |l| "-l#{l}" }.join(" ")
      end

      cmd = "#{@cxx} #{env('CFLAGS')} -lstdc++ -lm #{libs} -o #{basename} #{source} >>#{@log.path} 2>&1"
      @log.log cmd
      system cmd
      return $?.exitstatus unless run

      unless $?.exitstatus == 0
        @log.error "compiling configure test program failed"
        exit 1
      end

      `./#{basename}`
      return $?.exitstatus
    ensure
      File.delete(*Dir["#{basename}*"])
    end
  end

  def detect_sizeof_long
    @log.print "Checking sizeof(long): "

    @sizeof_long = check_program do |f|
      src = "int main() { return sizeof(long); }"
      f.puts src
      @log.log src
    end

    @log.write "#{@sizeof_long} bytes"
  end

  def detect_endian
    @log.print "Checking platform endianness: "

    status = check_program do |f|
      src = "int main() { int one = 1; return (*((char*)&one)) == 1 ? 0 : 1; }"
      f.puts src
      @log.log src
    end

    @little_endian = (status == 0)
    @log.write @little_endian ? "little endian" : "big endian"
  end

  def detect_tr1_hash
    @log.print "Checking tr1/hash definition: "

    status = check_program(false) do |f|
      src = <<-EOP
#include <stdint.h>
#include <tr1/unordered_map>

typedef std::tr1::unordered_map<uint64_t, void*> X;

int main() { X x; return 0; }
      EOP
      f.puts src
      @log.log src
    end

    @tr1_hash = (status == 0)
    @log.write @tr1_hash ? "found" : "not found"
  end

  def detect_curses
    @log.print "Checking curses library: "

    src = <<-EOP
#include <curses.h>
#include <term.h>

int main() { return tgetnum(""); }
    EOP

    ["curses", "ncurses", "termcap"].each do |lib|
      status = check_program(false, [lib]) do |f|
        f.puts src
        @log.log src
      end

      if status == 0
        @curses = lib
        break
      end
    end

    @log.write @curses ? @curses : "not found"
  end

  def has_function(name, includes=[])
    @log.print "Checking for function '#{name}': "
    tf = Tempfile.new("rbx-test")
    includes.each do |i|
      src = "#include <#{i}>"
      tf.puts src
      @log.log src
    end

    src = "int main() { void* ptr = &#{name}; }"
    tf.puts src
    @log.log src

    tf.close

    `#{@cxx} -S -o - -x c #{c_includes} #{env('CFLAGS')} #{tf.path} >>#{@log.path} 2>&1`
    status = ($?.exitstatus == 0)

    tf.unlink

    if status
      @log.write "found!"
    else
      @log.write "not found."
    end

    return status
  end

  def detect_features
    if @features["execinfo"] and has_function("backtrace", ["execinfo.h"])
      @defines << "HAS_EXECINFO"
    end

    if @features["C-readline"] and
       has_function("readline", ["stdio.h", "stdlib.h", "readline/readline.h"])
      @defines << "HAS_READLINE"
    end

    if @features["ruby-readline"] or !@defines.include?("HAS_READLINE")
      @rb_readline = true
    end
  end

  def process
    if @use_llvm
      @log.write "Configuring LLVM..."
      setup_auto
    else
      @log.write "WARNING: LLVM disabled."
    end

    @log.write ""

    detect_sizeof_long
    detect_endian
    detect_tr1_hash
    detect_features
    detect_curses
  end

  def which_ruby
    if Object.const_defined?(:RUBY_ENGINE)
      @which_ruby = RUBY_ENGINE.to_sym
    else
      @which_ruby = :ruby
    end
  end

  # Records the full path to the ruby executable that runs this configure
  # script. That path will be made available to the rest of the build system
  # so the same version of ruby is invoked as needed.
  def build_ruby
    unless @build_ruby
      bin = RbConfig::CONFIG["RUBY_INSTALL_NAME"] || RbConfig::CONFIG["ruby_install_name"]
      bin += (RbConfig::CONFIG['EXEEXT'] || RbConfig::CONFIG['exeext'] || '')
      @build_ruby = File.join(RbConfig::CONFIG['bindir'], bin)
    end
    @build_ruby
  end

  def get_system_name
    return unless @os =~ /linux/
    return unless File.exists? "/etc/issue"

    data = IO.readlines("/etc/issue").first
    data =~ /([^ ]+)[^\d\.]*([\d\.]*)/

    name = $1.downcase
    version = $2

    if name == "debian" and File.exists? "/etc/debian_version"
      version = IO.read("/etc/debian_version").split.first.gsub(/\W/, "-")
    end

    return "#{name}-#{version}"
  end

  def write_config
    unless @use_llvm
      @llvm = :no
      @llvm_configure = ""
    end

    File.open @config, "w" do |f|
      f.puts <<-EOC
module Rubinius
  BUILD_CONFIG = {
    :which_ruby     => :#{which_ruby},
    :build_ruby     => "#{build_ruby}",
    :build_rake     => "#{@rake}",
    :llvm           => :#{@llvm},
    :llvm_configure => "#{@llvm_configure}",
    :cc             => "#{@cc}",
    :cxx            => "#{@cxx}",
    :defines        => #{@defines.inspect},
    :curses         => #{@curses.inspect},
    :host           => "#{@host}",
    :cpu            => "#{@cpu}",
    :vendor         => "#{@vendor}",
    :os             => "#{@os}",
    :little_endian  => #{@little_endian},
    :sizeof_long    => #{@sizeof_long},
    :bindir         => "#{@bindir}",
    :libdir         => "#{@libdir}",
    :runtime        => "#{@runtime}",
    :lib_path       => "#{@lib_path}",
    :ext_path       => "#{@ext_path}",
    :includedir     => "#{@includedir}",
    :mandir         => "#{@mandir}",
    :gemsdir        => "#{@gemsdir}",
    :sitedir        => "#{@sitedir}",
    :vendordir      => "#{@vendordir}",
    :program_name   => "#{@program_name}",
    :version        => "#{@version}",
    :libversion     => "#{@libversion}",
    :release_date   => "#{@release_date}",
    :config_version => #{@config_version}
  }
end
      EOC
    end

    Dir.mkdir "lib/rubinius" unless File.directory? "lib/rubinius"
    FileUtils.cp @config, "lib/rubinius/build_config.rb"

    Dir.mkdir "vm/gen" unless File.directory? "vm/gen"

    File.open "vm/gen/config.h", "w" do |f|
      f.puts <<-EOC
#define RBX_HOST          "#{@host}"
#define RBX_CPU           "#{@cpu}"
#define RBX_VENDOR        "#{@vendor}"
#define RBX_OS            "#{@os}"
#define RBX_BIN_PATH      "#{@bindir}"
#define RBX_GEMS_PATH     "#{@gemsdir}"
#define RBX_RUNTIME       "#{@runtime}"
#define RBX_LIB_PATH      "#{@lib_path}"
#define RBX_EXT_PATH      "#{@ext_path}"
#define RBX_HDR_PATH      "#{@includedir}"
#define RBX_SITE_PATH     "#{@sitedir}"
#define RBX_VENDOR_PATH   "#{@vendordir}"
#define RBX_VERSION       "#{@version}"
#define RBX_LIB_VERSION   "#{@libversion}"
#define RBX_BUILD_REV     "#{@buildrev}"
#define RBX_LDSHARED      "#{@ldshared}"
#define RBX_RELEASE_DATE  "#{@release_date}"
#define RBX_SIZEOF_LONG   #{@sizeof_long}
      EOC

      if @little_endian
        f.puts "#define RBX_LITTLE_ENDIAN 1"
      end

      if @tr1_hash
        f.puts "#define RBX_HAVE_TR1_HASH 1"
      end
    end

    # Write a require file depending on which Readline library we use.
    File.open "lib/readline.rb", "w" do |f|
      if @rb_readline
        f.puts "require 'rb-readline/readline'"
      else
        f.puts "require 'c-readline'"
      end
    end
  end

  def print_debug
    puts "\nUsing the following configuration to build"
    puts "------------------------------------------"
    cat("config.rb")
    puts "\nSetting the following defines for the VM"
    puts "----------------------------------------"
    cat("vm/gen/config.h")
  end

  def cat(file)
    puts IO.read(relative_file(file))
  end

  def relative_file(name)
    File.expand_path("../#{name}", __FILE__)
  end

  def run
    unless which_ruby == :ruby or which_ruby == :rbx
      @log.error "Sorry, building Rubinius requires MRI or Rubinius"
      exit 1
    end

    options
    parse ARGV

    if File.join(@bindir, @program_name) == build_ruby
      @log.error "\nYou are attempting to build using the instance of Rubinius that you are building.\n\n"

      @log.error "To resolve this issue:"
      if ENV['PATH'] =~ /#{@bindir}/
        @log.error "  * Remove '#{@bindir}' from your PATH."
      end
      @log.error "  * Use a Ruby executable other than '#{build_ruby}' to build."

      exit 1
    end

    process
    write_config
    print_debug if @verbose
    if @install
      @log.write "\nConfigured. Run 'rake install' to install Rubinius."
    else
      @log.write <<-EOM

Configured. Run 'rake' to build and run VM tests and rubyspecs.

After building, you may add '#{@bindir}' to your PATH or run commands directly from that directory. Available commands are:

  #{@program_name}, ruby, rake, gem, irb, rdoc, ri

      EOM
    end
  end

  # Handles user output and logging while running configure.
  class Logger
    attr_reader :path

    # Creates an instance of Logger writing to +file+.
    def initialize(file, init=true)
      @path = File.expand_path("../#{file}", __FILE__)
      if init
        File.open(@path, "w") { }
        log "Configuring Rubinius..."
      end
    end

    # Copies the contents of +other+ into this logger's file.
    def replace(other)
      output do |f|
        f.puts File.read(other)
      end
    end

    # Writes +message+ to the logging file but not to the screen.
    def log(message, error=false)
      output do |f|
        stamp = "#{timestamp}#{'*** ERROR' if error}"
        if multiline?(message)
          f.puts "#{stamp} ---"
          f.puts message
          f.puts "---"
        else
          f.puts "#{stamp} #{message}"
        end
      end
    end

    # Writes a normal message to STDOUT and logs to the file.
    def write(message)
      log message
      STDOUT.puts message
    end

    # Writes a normal message to STDOUT with #print and logs to file.
    def print(message)
      log message
      STDOUT.print message
    end

    # Writes an error message to STDERR and logs to the file with
    # error decorations. This should only be used for errors that
    # affect configure itself.
    def error(message)
      log message, true
      STDERR.puts message
    end

    # Yields an IO for writing log messages.
    def output
      File.open @path, "a" do |f|
        yield f
      end
    end

    # Returns a formatted times suitable for logging.
    def timestamp
      Time.now.strftime "[%Y-%m-%d %H:%M:%S]"
    end

    # Returns true if the message has more than one line.
    def multiline?(message)
      message.index("\n") != nil
    end
  end
end

STDOUT.sync = true
Configure.new(root).run