class Gem::Commands::UpdateCommand

# File lib/rubygems/commands/update_command.rb, line 22
def initialize
  super 'update', 'Update installed gems to the latest version',
    :document => %w[rdoc ri],
    :force    => false

  add_install_update_options

  OptionParser.accept Gem::Version do |value|
    Gem::Version.new value

    value
  end

  add_option('--system [VERSION]', Gem::Version,
             'Update the RubyGems system software') do |value, options|
    value = true unless value

    options[:system] = value
  end

  add_local_remote_options
  add_platform_option
  add_prerelease_option "as update targets"

  @updated   = []
  @installer = nil
end

# File lib/rubygems/commands/update_command.rb, line 87
def execute
  if options[:system]
    update_rubygems
    return
  end

  hig = highest_installed_gems

  gems_to_update = which_to_update hig, options[:args].uniq

  if options[:explain]
    say "Gems to update:"

    gems_to_update.each do |(name, version)|
      say "  #{name}-#{version}"
    end

    return
  end

  say "Updating installed gems"

  updated = update_gems gems_to_update

  updated_names = updated.map { |spec| spec.name }
  not_updated_names = options[:args].uniq - updated_names

  if updated.empty?
    say "Nothing to update"
  else
    say "Gems updated: #{updated_names.join(' ')}"
    say "Gems already up-to-date: #{not_updated_names.join(' ')}" unless not_updated_names.empty?
  end
end

# File lib/rubygems/commands/update_command.rb, line 176
def rubygems_target_version
  version = options[:system]
  update_latest = version == true

  if update_latest
    version     = Gem::Version.new     Gem::VERSION
    requirement = Gem::Requirement.new ">= #{Gem::VERSION}"
  else
    version     = Gem::Version.new     version
    requirement = Gem::Requirement.new version
  end

  rubygems_update         = Gem::Specification.new
  rubygems_update.name    = 'rubygems-update'
  rubygems_update.version = version

  hig = {
    'rubygems-update' => rubygems_update
  }

  gems_to_update = which_to_update hig, options[:args], :system
  _, up_ver   = gems_to_update.first

  target = if update_latest
             up_ver
           else
             version
           end

  return target, requirement
end

# File lib/rubygems/commands/update_command.rb, line 208
def update_gem(name, version = Gem::Requirement.default)
  return if @updated.any? { |spec| spec.name == name }

  update_options = options.dup
  update_options[:prerelease] = version.prerelease?

  @installer = Gem::DependencyInstaller.new update_options

  say "Updating #{name}"
  begin
    @installer.install name, Gem::Requirement.new(version)
  rescue Gem::InstallError, Gem::DependencyError => e
    alert_error "Error installing #{name}:\n\t#{e.message}"
  end

  @installer.installed_gems.each do |spec|
    @updated << spec
  end
end

# File lib/rubygems/commands/update_command.rb, line 228
def update_gems(gems_to_update)
  gems_to_update.uniq.sort.each do |(name, version)|
    update_gem name, version
  end

  @updated
end

# File lib/rubygems/commands/update_command.rb, line 239
def update_rubygems
  check_update_arguments

  version, requirement = rubygems_target_version

  check_latest_rubygems version

  update_gem 'rubygems-update', version

  installed_gems = Gem::Specification.find_all_by_name 'rubygems-update', requirement
  version        = installed_gems.first.version

  install_rubygems version
end

# File lib/rubygems/commands/update_command.rb, line 267
def which_to_update(highest_installed_gems, gem_names, system = false)
  result = []

  highest_installed_gems.each do |l_name, l_spec|
    next if not gem_names.empty? and
            gem_names.none? { |name| name == l_spec.name }

    highest_remote_ver = highest_remote_version l_spec

    if system or (l_spec.version < highest_remote_ver)
      result << [l_spec.name, [l_spec.version, highest_remote_ver].max]
    end
  end

  result
end