module Gem::BundlerVersionFinder

# File lib/rubygems/bundler_version_finder.rb, line 4
def self.bundler_version
  v = ENV["BUNDLER_VERSION"]

  v ||= bundle_update_bundler_version
  return if v == true

  v ||= lockfile_version
  return unless v

  Gem::Version.new(v)
end

# File lib/rubygems/bundler_version_finder.rb, line 16
def self.prioritize!(specs)
  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 23
def self.bundle_update_bundler_version
  return unless File.basename($0) == "bundle"
  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 48
def self.lockfile_contents
  gemfile = ENV["BUNDLE_GEMFILE"]
  gemfile = nil if 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)

  File.read(lockfile)
end

# File lib/rubygems/bundler_version_finder.rb, line 40
def self.lockfile_version
  return unless contents = lockfile_contents
  regexp = /\n\nBUNDLED WITH\n\s{2,}(#{Gem::Version::VERSION_PATTERN})\n/
  return unless contents =~ regexp
  $1
end