module Gem::BundlerVersionFinder

# File lib/rubygems/bundler_version_finder.rb, line 4
def self.bundler_version
  version, _ = bundler_version_with_reason

  return unless version

  Gem::Version.new(version)
end

# File lib/rubygems/bundler_version_finder.rb, line 12
def self.bundler_version_with_reason
  if v = ENV["BUNDLER_VERSION"]
    return [v, "`$BUNDLER_VERSION`"]
  end
  if v = bundle_update_bundler_version
    return if v == true
    return [v, "`bundle update --bundler`"]
  end
  v, lockfile = lockfile_version
  if v
    return [v, "your #{lockfile}"]
  end
end

# File lib/rubygems/bundler_version_finder.rb, line 35
def self.compatible?(spec)
  return true unless spec.name == "bundler".freeze
  return true unless bundler_version = self.bundler_version

  spec.version.segments.first == bundler_version.segments.first
end

# File lib/rubygems/bundler_version_finder.rb, line 42
def self.filter!(specs)
  return unless bundler_version = self.bundler_version

  specs.reject! {|spec| spec.version.segments.first != bundler_version.segments.first }

  exact_match_index = specs.find_index {|spec| spec.version == bundler_version }
  return unless exact_match_index

  specs.unshift(specs.delete_at(exact_match_index))
end

# File lib/rubygems/bundler_version_finder.rb, line 26
  def self.missing_version_message
    return unless vr = bundler_version_with_reason
    <<-EOS
Could not find 'bundler' (#{vr.first}) required by #{vr.last}.
To update to the latest version installed on your system, run `bundle update --bundler`.
To install the missing version, run `gem install bundler:#{vr.first}`
    EOS
  end

# File lib/rubygems/bundler_version_finder.rb, line 53
def self.bundle_update_bundler_version
  return unless File.basename($0) == "bundle".freeze
  return unless "update".start_with?(ARGV.first || " ")
  bundler_version = nil
  update_index = nil
  ARGV.each_with_index do |a, i|
    if update_index && update_index.succ == i && a =~ Gem::Version::ANCHORED_VERSION_PATTERN
      bundler_version = a
    end
    next unless a =~ /\A--bundler(?:[= ](#{Gem::Version::VERSION_PATTERN}))?\z/
    bundler_version = $1 || true
    update_index = i
  end
  bundler_version
end

# File lib/rubygems/bundler_version_finder.rb, line 80
def self.lockfile_contents
  gemfile = ENV["BUNDLE_GEMFILE"]
  gemfile = nil if gemfile && gemfile.empty?

  unless gemfile
    begin
      Gem::Util.traverse_parents(Dir.pwd) do |directory|
        next unless gemfile = Gem::GEM_DEP_FILES.find {|f| File.file?(f.tap(&Gem::UNTAINT)) }

        gemfile = File.join directory, gemfile
        break
      end
    rescue Errno::ENOENT
      return
    end
  end

  return unless gemfile

  lockfile = case gemfile
             when "gems.rb" then "gems.locked"
             else "#{gemfile}.lock"
             end.dup.tap(&Gem::UNTAINT)

  return unless File.file?(lockfile)

  [lockfile, File.read(lockfile)]
end

# File lib/rubygems/bundler_version_finder.rb, line 70
def self.lockfile_version
  return unless lockfile = lockfile_contents
  lockfile, contents = lockfile
  lockfile ||= "lockfile"
  regexp = /\n\nBUNDLED WITH\n\s{2,}(#{Gem::Version::VERSION_PATTERN})\n/
  return unless contents =~ regexp
  [$1, lockfile]
end