class Gem::Installer

# File lib/rubygems/installer.rb, line 85
def self.at(path, options = {})
  security_policy = options[:security_policy]
  package = Gem::Package.new path, security_policy
  new package, options
end

# File lib/rubygems/installer.rb, line 77
def exec_format
  @exec_format ||= Gem.default_exec_format
end

# File lib/rubygems/installer.rb, line 123
def self.for_spec(spec, options = {})
  # FIXME: we should have a real Package class for this
  new FakePackage.new(spec), options
end

# File lib/rubygems/installer.rb, line 153
def initialize(package, options = {})
  require "fileutils"

  @options = options
  @package = package

  process_options

  @package.dir_mode = options[:dir_mode]
  @package.prog_mode = options[:prog_mode]
  @package.data_mode = options[:data_mode]
end

# File lib/rubygems/installer.rb, line 715
  def app_script_text(bin_file_name)
    # NOTE: that the `load` lines cannot be indented, as old RG versions match
    # against the beginning of the line
    <<~TEXT
      #{shebang bin_file_name}
      #
      # This file was generated by RubyGems.
      #
      # The application '#{spec.name}' is installed as part of a gem, and
      # this file is here to facilitate running it.
      #

      require 'rubygems'
      #{gemdeps_load(spec.name)}
      version = "#{Gem::Requirement.default_prerelease}"

      str = ARGV.first
      if str
        str = str.b[/\\A_(.*)_\\z/, 1]
        if str and Gem::Version.correct?(str)
          #{explicit_version_requirement(spec.name)}
          ARGV.shift
        end
      end

      if Gem.respond_to?(:activate_and_load_bin_path)
        Gem.activate_and_load_bin_path('#{spec.name}', '#{bin_file_name}', version)
      else
        load Gem.activate_bin_path('#{spec.name}', '#{bin_file_name}', version)
      end
    TEXT
  end

# File lib/rubygems/installer.rb, line 806
def build_extensions
  builder = Gem::Ext::Builder.new spec, build_args, Gem.target_rbconfig, build_jobs

  builder.build_extensions
end

# File lib/rubygems/installer.rb, line 389
def default_spec_dir
  dir = File.join(gem_home, "specifications", "default")
  FileUtils.mkdir_p dir
  dir
end

# File lib/rubygems/installer.rb, line 399
def default_spec_file
  File.join default_spec_dir, "#{spec.full_name}.gemspec"
end

# File lib/rubygems/installer.rb, line 847
def dir
  gem_dir.to_s
end

# File lib/rubygems/installer.rb, line 364
def ensure_dependency(spec, dependency)
  unless installation_satisfies_dependency? dependency
    raise Gem::InstallError, "#{spec.name} requires #{dependency}"
  end
  true
end

# File lib/rubygems/installer.rb, line 595
def ensure_loadable_spec
  ruby = spec.to_ruby_for_cache

  begin
    eval ruby
  rescue StandardError, SyntaxError => e
    raise Gem::InstallError,
          "The specification for #{spec.full_name} is corrupt (#{e.class})"
  end
end

# File lib/rubygems/installer.rb, line 757
  def explicit_version_requirement(name)
    code = "version = str"
    return code unless name == "bundler"

    code += <<~TEXT

      ENV['BUNDLER_VERSION'] = str
    TEXT
  end

# File lib/rubygems/installer.rb, line 826
def extract_bin
  @package.extract_files gem_dir, "#{spec.bindir}/*"
end

# File lib/rubygems/installer.rb, line 817
def extract_files
  @package.extract_files gem_dir
end

# File lib/rubygems/installer.rb, line 833
def formatted_program_filename(filename)
  if @format_executable
    self.class.exec_format % File.basename(filename)
  else
    filename
  end
end

# File lib/rubygems/installer.rb, line 854
def gem
  @package.gem.path
end

# File lib/rubygems/installer.rb, line 246
def gem_dir
  @gem_dir ||= File.join(gem_home, "gems", spec.full_name)
end

# File lib/rubygems/installer.rb, line 748
  def gemdeps_load(name)
    return "" if name == "bundler"

    <<~TEXT

      Gem.use_gemdeps
    TEXT
  end

# File lib/rubygems/installer.rb, line 497
def generate_bin_script(filename, bindir)
  bin_script_path = File.join bindir, formatted_program_filename(filename)

  Gem.open_file_with_lock(bin_script_path) do
    require "fileutils"
    FileUtils.rm_f bin_script_path # prior install may have been --no-wrappers

    File.open(bin_script_path, "wb", 0o755) do |file|
      file.write app_script_text(filename)
      file.chmod(options[:prog_mode] || 0o755)
    end
  end

  verbose bin_script_path

  generate_windows_script filename, bindir
end

# File lib/rubygems/installer.rb, line 519
def generate_bin_symlink(filename, bindir)
  src = File.join gem_dir, spec.bindir, filename
  dst = File.join bindir, formatted_program_filename(filename)

  if File.exist? dst
    if File.symlink? dst
      link = File.readlink(dst).split File::SEPARATOR
      cur_version = Gem::Version.create(link[-3].sub(/^.*-/, ""))
      return if spec.version < cur_version
    end
    File.unlink dst
  end

  FileUtils.symlink src, dst, verbose: Gem.configuration.really_verbose
rescue NotImplementedError, SystemCallError
  alert_warning "Unable to use symlinks, installing wrapper"
  generate_bin_script filename, bindir
end

# File lib/rubygems/installer.rb, line 427
def generate_windows_script(filename, bindir)
  if Gem.win_platform?
    script_name = formatted_program_filename(filename) + ".bat"
    script_path = File.join bindir, File.basename(script_name)
    File.open script_path, "w" do |file|
      file.puts windows_stub_script(bindir, filename)
    end

    verbose script_path
  end
end

# File lib/rubygems/installer.rb, line 268
def install
  pre_install_checks

  run_pre_install_hooks

  # Set loaded_from to ensure extension_dir is correct
  spec.loaded_from = spec_file

  # Completely remove any previous gem files
  FileUtils.rm_rf gem_dir
  FileUtils.rm_rf spec.extension_dir

  dir_mode = options[:dir_mode]
  FileUtils.mkdir_p gem_dir, mode: dir_mode && 0o755

  extract_files

  build_extensions
  write_build_info_file
  run_post_build_hooks

  generate_bin
  generate_plugins

  write_spec
  write_cache_file

  File.chmod(dir_mode, gem_dir) if dir_mode

  say spec.post_install_message if options[:post_install_message] && !spec.post_install_message.nil?

  Gem::Specification.add_spec(spec) unless @install_dir

  load_plugin

  run_post_install_hooks

  spec
rescue Errno::EACCES => e
  # Permission denied - /path/to/foo
  raise Gem::FilePermissionError, e.message.split(" - ").last
end

# File lib/rubygems/installer.rb, line 374
def installation_satisfies_dependency?(dependency)
  return true if @options[:development] && dependency.type == :development
  return true if installed_specs.detect {|s| dependency.matches_spec? s }
  return false if @only_install_dir
  !dependency.matching_specs.empty?
end

# File lib/rubygems/installer.rb, line 344
def installed_specs
  @installed_specs ||= begin
    specs = []

    Gem::Util.glob_files_in_dir("*.gemspec", File.join(gem_home, "specifications")).each do |path|
      spec = Gem::Specification.load path
      specs << spec if spec
    end

    specs
  end
end

# File lib/rubygems/installer.rb, line 867
def pre_install_checks
  verify_gem_home

  # The name and require_paths must be verified first, since it could contain
  # ruby code that would be eval'ed in #ensure_loadable_spec
  verify_spec

  ensure_loadable_spec

  Gem.ensure_gem_subdirectories gem_home

  return true if @force

  ensure_dependencies_met unless @ignore_dependencies

  true
end

# File lib/rubygems/installer.rb, line 553
def shebang(bin_file_name)
  path = File.join gem_dir, spec.bindir, bin_file_name
  first_line = File.open(path, "rb", &:gets) || ""

  if first_line.start_with?("#!")
    # Preserve extra words on shebang line, like "-w".  Thanks RPA.
    shebang = first_line.sub(/\A\#!.*?ruby\S*((\s+\S+)+)/, "#!#{Gem.ruby}")
    opts = $1
    shebang.strip! # Avoid nasty ^M issues.
  end

  if which = Gem.configuration[:custom_shebang]
    # replace bin_file_name with "ruby" to avoid endless loops
    which = which.gsub(/ #{bin_file_name}$/," #{ruby_install_name}")

    which = which.gsub(/\$(\w+)/) do
      case $1
      when "env"
        @env_path ||= ENV_PATHS.find {|env_path| File.executable? env_path }
      when "ruby"
        "#{Gem.ruby}#{opts}"
      when "exec"
        bin_file_name
      when "name"
        spec.name
      end
    end

    "#!#{which}"
  elsif @env_shebang
    # Create a plain shebang line.
    @env_path ||= ENV_PATHS.find {|env_path| File.executable? env_path }
    "#!#{@env_path} #{ruby_install_name}"
  else
    "#{bash_prolog_script}#!#{Gem.ruby}#{opts}"
  end
end

# File lib/rubygems/installer.rb, line 253
def spec
  @package.spec
end

# File lib/rubygems/installer.rb, line 385
def spec_file
  File.join gem_home, "specifications", "#{spec.full_name}.gemspec"
end

# File lib/rubygems/installer.rb, line 682
def verify_spec
  unless Gem::Specification::VALID_NAME_PATTERN.match?(spec.name)
    raise Gem::InstallError, "#{spec} has an invalid name"
  end

  if spec.raw_require_paths.any? {|path| path =~ /\R/ }
    raise Gem::InstallError, "#{spec} has an invalid require_paths"
  end

  if spec.extensions.any? {|ext| ext =~ /\R/ }
    raise Gem::InstallError, "#{spec} has an invalid extensions"
  end

  if /\R/.match?(spec.platform.to_s)
    raise Gem::InstallError, "#{spec.platform} is an invalid platform"
  end

  unless /\A\d+\z/.match?(spec.specification_version.to_s)
    raise Gem::InstallError, "#{spec} has an invalid specification_version"
  end

  if spec.dependencies.any? {|dep| dep.type != :runtime && dep.type != :development }
    raise Gem::InstallError, "#{spec} has an invalid dependencies"
  end

  if spec.dependencies.any? {|dep| dep.name =~ /(?:\R|[<>])/ }
    raise Gem::InstallError, "#{spec} has an invalid dependencies"
  end
end

# File lib/rubygems/installer.rb, line 770
  def windows_stub_script(bindir, bin_file_name)
    rb_topdir = RbConfig::TOPDIR || File.dirname(rb_config["bindir"])

    # get ruby executable file name from RbConfig
    ruby_exe = "#{rb_config["RUBY_INSTALL_NAME"]}#{rb_config["EXEEXT"]}"
    ruby_exe = "ruby.exe" if ruby_exe.empty?

    if File.exist?(File.join(bindir, ruby_exe))
      # stub & ruby.exe within same folder.  Portable
      <<~TEXT
        @ECHO OFF
        @"%~dp0#{ruby_exe}" "%~dpn0" %*
      TEXT
    elsif bindir.downcase.start_with? rb_topdir.downcase
      # stub within ruby folder, but not standard bin.  Portable
      require "pathname"
      from = Pathname.new bindir
      to   = Pathname.new "#{rb_topdir}/bin"
      rel  = to.relative_path_from from
      <<~TEXT
        @ECHO OFF
        @"%~dp0#{rel}/#{ruby_exe}" "%~dpn0" %*
      TEXT
    else
      # outside ruby folder, maybe -user-install or bundler.  Portable, but ruby
      # is dependent on PATH
      <<~TEXT
        @ECHO OFF
        @#{ruby_exe} "%~dpn0" %*
      TEXT
    end
  end

# File lib/rubygems/installer.rb, line 889
def write_build_info_file
  return if build_args.empty?

  build_info_dir = File.join gem_home, "build_info"

  dir_mode = options[:dir_mode]
  FileUtils.mkdir_p build_info_dir, mode: dir_mode && 0o755

  build_info_file = File.join build_info_dir, "#{spec.full_name}.info"

  File.open build_info_file, "w" do |io|
    build_args.each do |arg|
      io.puts arg
    end
  end

  File.chmod(dir_mode, build_info_dir) if dir_mode
end

# File lib/rubygems/installer.rb, line 911
def write_cache_file
  cache_file = File.join gem_home, "cache", spec.file_name
  @package.copy_to cache_file
end

# File lib/rubygems/installer.rb, line 420
def write_default_spec
  Gem.write_binary(default_spec_file, spec.to_ruby)
end

# File lib/rubygems/installer.rb, line 407
def write_spec
  spec.installed_by_version = Gem.rubygems_version

  Gem.write_binary(spec_file, spec.to_ruby_for_cache)
end

# File lib/rubygems/installer.rb, line 961
  def bash_prolog_script
    if load_relative_enabled?
      <<~EOS
        #!/bin/sh
        # -*- ruby -*-
        _=_\\
        =begin
        bindir="${0%/*}"
        ruby="$bindir/#{ruby_install_name}"
        if [ ! -f "$ruby" ]; then
          ruby="#{ruby_install_name}"
        fi
        exec "$ruby" "-x" "$0" "$@"
        =end
      EOS
    else
      ""
    end
  end

# File lib/rubygems/installer.rb, line 938
def build_args
  @build_args ||= begin
                    require_relative "command"
                    Gem::Command.build_args
                  end
end

# File lib/rubygems/installer.rb, line 945
def build_jobs
  @build_jobs ||= Etc.nprocessors + 1
end

# File lib/rubygems/installer.rb, line 981
def load_plugin
  specs = Gem::Specification.find_all_by_name(spec.name)
  # If old version already exists, this plugin isn't loaded
  # immediately. It's for avoiding a case that multiple versions
  # are loaded at the same time.
  return unless specs.size == 1

  plugin_files = spec.plugins.map do |plugin|
    File.join(@plugins_dir, "#{spec.name}_plugin#{File.extname(plugin)}")
  end
  Gem.load_plugin_files(plugin_files)
end

# File lib/rubygems/installer.rb, line 957
def load_relative_enabled?
  rb_config["LIBRUBY_RELATIVE"] == "yes"
end

# File lib/rubygems/installer.rb, line 949
def rb_config
  Gem.target_rbconfig
end

# File lib/rubygems/installer.rb, line 953
def ruby_install_name
  rb_config["ruby_install_name"]
end

# File lib/rubygems/installer.rb, line 925
def user_install_dir
  # never install to user home in --build-root mode
  return unless @build_root.nil?

  # Please note that @user_install might have three states:
  # * `true`: `--user-install`
  # * `false`: `--no-user-install` and
  # * `nil`: option was not specified
  if @user_install || (@user_install.nil? && Gem.default_user_install)
    Gem.user_dir
  end
end