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Class: Gem::Installer

Relationships & Source Files
Namespace Children
Classes:
Super Chains via Extension / Inclusion / Inheritance
Class Chain:
self, Deprecate
Instance Chain:
Inherits: Object
Defined in: lib/rubygems/installer.rb

Overview

The installer installs the files contained in the #gem into the Gem.home.

Installer does the work of putting files in all the right places on the filesystem including unpacking the gem into its gem dir, installing the gemspec in the specifications dir, storing the cached gem in the cache dir, and installing either wrappers or symlinks for executables.

The installer invokes pre and post install hooks. Hooks can be added either through a rubygems_plugin.rb file in an installed gem or via a rubygems/defaults/#RUBY_ENGINE.rb or rubygems/defaults/operating_system.rb file. See pre_install and post_install for details.

Constant Summary

Class Attribute Summary

Class Method Summary

Deprecate - Extended

deprecate

Simple deprecation method that deprecates name by wrapping it up in a dummy method.

rubygems_deprecate

Simple deprecation method that deprecates name by wrapping it up in a dummy method.

rubygems_deprecate_command

Deprecation method to deprecate Rubygems commands.

skip_during

Temporarily turn off warnings.

Instance Attribute Summary

DefaultUserInteraction - Included

Instance Method Summary

InstallerUninstallerUtils - Included

UserInteraction - Included

#alert

Displays an alert statement.

#alert_error

Displays an error statement to the error output location.

#alert_warning

Displays a warning statement to the warning output location.

#ask

Asks a question and returns the answer.

#ask_for_password

Asks for a password with a prompt

#ask_yes_no

Asks a yes or no question.

#choose_from_list

Asks the user to answer question with an answer from the given list.

#say

Displays the given statement on the standard output (or equivalent).

#terminate_interaction

Terminates the RubyGems process with the given exit_code

#verbose

Calls say with msg or the results of the block if really_verbose is true.

DefaultUserInteraction - Included

Text - Included

#clean_text

Remove any non-printable characters and make the text suitable for printing.

#format_text

Wraps text to wrap characters and optionally indents by indent characters.

#levenshtein_distance

Returns a value representing the “cost” of transforming str1 into str2 Vendored version of DidYouMean::Levenshtein.distance from the ruby/did_you_mean gem @ 1.4.0 git.io/JJgZI.

#truncate_text, #min3

Constructor Details

.new(package, options = {}) ⇒ Installer

Constructs an Installer instance that will install the gem at #package which can either be a path or an instance of Package. #options is a Hash with the following keys:

:bin_dir

Where to put a bin wrapper if needed.

:development

Whether or not development dependencies should be installed.

:env_shebang

Use /usr/bin/env in bin wrappers.

:force

Overrides all version checks and security policy checks, except for a signed-gems-only policy.

:format_executable

Format the executable the same as the Ruby executable. If your Ruby is ruby18, foo_exec will be installed as foo_exec18.

:ignore_dependencies

Don’t raise if a dependency is missing.

:install_dir

The directory to install the gem into.

:security_policy

Use the specified security policy. See Security

:user_install

Indicate that the gem should be unpacked into the users personal gem directory.

:only_install_dir

Only validate dependencies against what is in the install_dir

:wrappers

Install wrappers if true, symlinks if false.

:build_args

An Array of arguments to pass to the extension builder process. If not set, then Gem::Command.build_args is used

:post_install_message

Print gem post install message if true

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 179

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]

  if options[:user_install]
    @gem_home = Gem.user_dir
    @bin_dir = Gem.bindir gem_home unless options[:bin_dir]
    @plugins_dir = Gem.plugindir(gem_home)
    check_that_user_bin_dir_is_in_path
  end
end

Class Attribute Details

.exec_format (rw)

Defaults to use Ruby’s program prefix and suffix.

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 103

def exec_format
  @exec_format ||= Gem.default_exec_format
end

.exec_format=(value) (rw)

Overrides the executable format.

This is a sprintf format with a “%s” which will be replaced with the executable name. It is based off the ruby executable name’s difference from “ruby”.

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 100

attr_writer :exec_format

.path_warning (rw)

True if we’ve warned about PATH not including Gem.bindir

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# File 'lib/rubygems/installer.rb', line 91

attr_accessor :path_warning

Class Method Details

.at(path, options = {})

Construct an installer object for the gem file located at Gem.path

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 111

def self.at(path, options = {})
  security_policy = options[:security_policy]
  package = Gem::Package.new path, security_policy
  new package, options
end

.for_spec(spec, options = {})

Construct an installer object for an ephemeral gem (one where we don’t actually have a #gem file, just a spec)

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 149

def self.for_spec(spec, options = {})
  # FIXME: we should have a real Package class for this
  new FakePackage.new(spec), options
end

.inherited(klass)

Changes in rubygems to lazily loading rubygems/command (in order to lazily load optparse as a side effect) affect bundler’s custom installer which uses Command without requiring it (up until bundler 2.2.29). This hook is to compensate for that missing require.

TODO: Remove when rubygems no longer supports running on bundler older than 2.2.29.

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 80

def inherited(klass)
  if klass.name == "Bundler::RubyGemsGemInstaller"
    require "rubygems/command"
  end

  super(klass)
end

Instance Attribute Details

#bin_dir (readonly)

The directory a gem’s executables will be installed into

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# File 'lib/rubygems/installer.rb', line 49

attr_reader :bin_dir

#build_root (readonly)

This method is for internal use only.
[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 51

attr_reader :build_root # :nodoc:

#gem_home (readonly)

The gem repository the gem will be installed into

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# File 'lib/rubygems/installer.rb', line 56

attr_reader :gem_home

#load_relative_enabled?Boolean (readonly, private)

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 981

def load_relative_enabled?
  rb_config["LIBRUBY_RELATIVE"] == "yes"
end

#options (readonly)

The options passed when the Installer was instantiated.

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 61

attr_reader :options

#package (readonly)

The gem package instance.

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 66

attr_reader :package

Instance Method Details

#app_script_text(bin_file_name)

Return the text for an application file.

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 748

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
  return <<-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_bin_path)
load Gem.activate_bin_path('#{spec.name}', '#{bin_file_name}', version)
else
gem #{spec.name.dump}, version
load Gem.bin_path(#{spec.name.dump}, #{bin_file_name.dump}, version)
end
TEXT
end

#bash_prolog_script (private)

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 985

def bash_prolog_script
  if load_relative_enabled?
    script = +<<~EOS
      bindir="${0%/*}"
    EOS

    script << %Q(exec "$bindir/#{ruby_install_name}" "-x" "$0" "$@"\n)

    <<~EOS
      #!/bin/sh
      # -*- ruby -*-
      _=_\\
      =begin
      #{script.chomp}
      =end
    EOS
  else
    ""
  end
end

#build_args (private)

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 966

def build_args
  @build_args ||= begin
                    require_relative "command"
                    Gem::Command.build_args
                  end
end

#build_extensions

Builds extensions. Valid types of extensions are extconf.rb files, configure scripts and rakefiles or mkrf_conf files.

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 840

def build_extensions
  builder = Gem::Ext::Builder.new spec, build_args

  builder.build_extensions
end

#check_executable_overwrite(filename)

This method is for internal use only.

Checks if filename exists in @bin_dir.

If @force is set filename is overwritten.

If filename exists and it is a RubyGems wrapper for a different gem, then the user is consulted.

If filename exists and @bin_dir is Gem.default_bindir (/usr/local) the user is consulted.

Otherwise filename is overwritten.

Raises:

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 212

def check_executable_overwrite(filename) # :nodoc:
  return if @force

  generated_bin = File.join @bin_dir, formatted_program_filename(filename)

  return unless File.exist? generated_bin

  ruby_executable = false
  existing = nil

  File.open generated_bin, "rb" do |io|
    line = io.gets
    shebang = /^#!.*ruby/

    if load_relative_enabled?
      until line.nil? || line =~ shebang do
        line = io.gets
      end
    end

    next unless line =~ shebang

    io.gets # blankline

    # TODO detect a specially formatted comment instead of trying
    # to run a regexp against Ruby code.
    next unless io.gets =~ /This file was generated by RubyGems/

    ruby_executable = true
    existing = io.read.slice(%r{
        ^\s*(
          gem \s |
          load \s Gem\.bin_path\( |
          load \s Gem\.activate_bin_path\(
        )
        (['"])(.*?)(\2),
      }x, 3)
  end

  return if spec.name == existing

  # somebody has written to RubyGems' directory, overwrite, too bad
  return if Gem.default_bindir != @bin_dir && !ruby_executable

  question = "#{spec.name}'s executable \"#{filename}\" conflicts with ".dup

  if ruby_executable
    question << (existing || "an unknown executable")

    return if ask_yes_no "#{question}\nOverwrite the executable?", false

    conflict = "installed executable from #{existing}"
  else
    question << generated_bin

    return if ask_yes_no "#{question}\nOverwrite the executable?", false

    conflict = generated_bin
  end

  raise Gem::InstallError,
    "\"#{filename}\" from #{spec.name} conflicts with #{conflict}"
end

#check_that_user_bin_dir_is_in_path

This method is for internal use only.
[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 686

def check_that_user_bin_dir_is_in_path # :nodoc:
  return if self.class.path_warning

  user_bin_dir = @bin_dir || Gem.bindir(gem_home)
  user_bin_dir = user_bin_dir.tr(File::ALT_SEPARATOR, File::SEPARATOR) if File::ALT_SEPARATOR

  path = ENV["PATH"]
  path = path.tr(File::ALT_SEPARATOR, File::SEPARATOR) if File::ALT_SEPARATOR

  if Gem.win_platform?
    path = path.downcase
    user_bin_dir = user_bin_dir.downcase
  end

  path = path.split(File::PATH_SEPARATOR)

  unless path.include? user_bin_dir
    unless !Gem.win_platform? && (path.include? user_bin_dir.sub(ENV["HOME"], "~"))
      alert_warning "You don't have #{user_bin_dir} in your PATH,\n\t  gem executables will not run."
      self.class.path_warning = true
    end
  end
end

#default_spec_file

The location of the default spec file for default gems.

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 448

def default_spec_file
  File.join gem_home, "specifications", "default", "#{spec.full_name}.gemspec"
end

#dir

Return the target directory where the gem is to be installed. This directory is not guaranteed to be populated.

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 881

def dir
  gem_dir.to_s
end

#ensure_dependencies_met

This method is for internal use only.
[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 641

def ensure_dependencies_met # :nodoc:
  deps = spec.runtime_dependencies
  deps |= spec.development_dependencies if @development

  deps.each do |dep_gem|
    ensure_dependency spec, dep_gem
  end
end

#ensure_dependency(spec, dependency)

Ensure that the dependency is satisfied by the current installation of gem. If it is not an exception is raised.

spec

Specification

dependency

Dependency

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 410

def ensure_dependency(spec, dependency)
  unless installation_satisfies_dependency? dependency
    raise Gem::InstallError, "#{spec.name} requires #{dependency}"
  end
  true
end

#ensure_loadable_spec

Ensures the Specification written out for this gem is loadable upon installation.

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 629

def ensure_loadable_spec
  ruby = spec.to_ruby_for_cache
  ruby.tap(&Gem::UNTAINT)

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

#ensure_writable_dir(dir)

This method is for internal use only.
[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 954

def ensure_writable_dir(dir) # :nodoc:
  begin
    Dir.mkdir dir, *[options[:dir_mode] && 0755].compact
  rescue SystemCallError
    raise unless File.directory? dir
  end

  raise Gem::FilePermissionError.new(dir) unless File.writable? dir
end

#explicit_version_requirement(name)

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 791

def explicit_version_requirement(name)
  code = "version = str"
  return code unless name == "bundler"

  code += <<-TEXT

  ENV['BUNDLER_VERSION'] = str
TEXT
end

#extract_bin

Extracts only the bin/ files from the gem into the gem directory. This is used by default gems to allow a gem-aware stub to function without the full gem installed.

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 860

def extract_bin
  @package.extract_files gem_dir, "#{spec.bindir}/*"
end

#extract_files

Reads the file index and extracts each file into the gem directory.

Ensures that files can’t be installed outside the gem directory.

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 851

def extract_files
  @package.extract_files gem_dir
end

#formatted_program_filename(filename)

Prefix and suffix the program filename the same as ruby.

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 867

def formatted_program_filename(filename)
  if @format_executable
    self.class.exec_format % File.basename(filename)
  else
    filename
  end
end

#gem

Filename of the gem being installed.

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 888

def gem
  @package.gem.path
end

#gem_dir

Lazy accessor for the spec’s gem directory.

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 279

def gem_dir
  @gem_dir ||= File.join(gem_home, "gems", spec.full_name)
end

#gemdeps_load(name)

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 782

def gemdeps_load(name)
  return "" if name == "bundler"

  <<-TEXT

Gem.use_gemdeps
TEXT
end

#generate_bin

This method is for internal use only.
[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 485

def generate_bin # :nodoc:
  return if spec.executables.nil? || spec.executables.empty?

  ensure_writable_dir @bin_dir

  spec.executables.each do |filename|
    filename.tap(&Gem::UNTAINT)
    bin_path = File.join gem_dir, spec.bindir, filename
    next unless File.exist? bin_path

    mode = File.stat(bin_path).mode
    dir_mode = options[:prog_mode] || (mode | 0111)

    unless dir_mode == mode
      require "fileutils"
      FileUtils.chmod dir_mode, bin_path
    end

    check_executable_overwrite filename

    if @wrappers
      generate_bin_script filename, @bin_dir
    else
      generate_bin_symlink filename, @bin_dir
    end
  end
end

#generate_bin_script(filename, bindir)

Creates the scripts to run the applications in the gem.

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 533

def generate_bin_script(filename, bindir)
  bin_script_path = File.join bindir, formatted_program_filename(filename)

  require "fileutils"
  FileUtils.rm_f bin_script_path # prior install may have been --no-wrappers

  File.open bin_script_path, "wb", 0755 do |file|
    file.print app_script_text(filename)
    file.chmod(options[:prog_mode] || 0755)
  end

  verbose bin_script_path

  generate_windows_script filename, bindir
end

#generate_plugins

This method is for internal use only.
[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 513

def generate_plugins # :nodoc:
  latest = Gem::Specification.latest_spec_for(spec.name)
  return if latest && latest.version > spec.version

  ensure_writable_dir @plugins_dir

  if spec.plugins.empty?
    remove_plugins_for(spec, @plugins_dir)
  else
    regenerate_plugins_for(spec, @plugins_dir)
  end
end

#generate_windows_script(filename, bindir)

Creates windows .bat files for easy running of commands

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 473

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

#install

Installs the gem and returns a loaded Specification for the installed gem.

The gem will be installed with the following structure:

@gem_home/
  cache/<gem-version>.gem #=> a cached copy of the installed gem
  gems/<gem-version>/... #=> extracted files
  specifications/<gem-version>.gemspec #=> the Gem::Specification
[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 301

def install
  pre_install_checks

  run_pre_install_hooks

  # Set loaded_from to ensure extension_dir is correct
  if @options[:install_as_default]
    spec.loaded_from = default_spec_file
  else
    spec.loaded_from = spec_file
  end

  # 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 && 0755

  if @options[:install_as_default]
    extract_bin
    write_default_spec
  else
    extract_files

    build_extensions
    write_build_info_file
    run_post_build_hooks
  end

  generate_bin
  generate_plugins

  unless @options[:install_as_default]
    write_spec
    write_cache_file
  end

  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)

  run_post_install_hooks

  spec

# TODO This rescue is in the wrong place. What is raising this exception?
# move this rescue to around the code that actually might raise it.
rescue Zlib::GzipFile::Error
  raise Gem::InstallError, "gzip error installing #{gem}"
end

#installation_satisfies_dependency?(dependency) ⇒ Boolean

True if the gems in the system satisfy dependency.

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 420

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

#installed_specs

Return an Array of Specifications contained within the gem_home we’ll be installing into.

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 390

def installed_specs
  @specs ||= begin
    specs = []

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

    specs
  end
end

#pre_install_checks

Performs various checks before installing the gem such as the install repository is writable and its directories exist, required Ruby and rubygems versions are met and that dependencies are installed.

Version and dependency checks are skipped if this install is forced.

The dependent check will be skipped if the install is ignoring dependencies.

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 901

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

  if options[:install_as_default]
    Gem.ensure_default_gem_subdirectories gem_home
  else
    Gem.ensure_gem_subdirectories gem_home
  end

  return true if @force

  ensure_dependencies_met unless @ignore_dependencies

  true
end

#process_options

This method is for internal use only.
[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 650

def process_options # :nodoc:
  @options = {
    :bin_dir      => nil,
    :env_shebang  => false,
    :force        => false,
    :only_install_dir => false,
    :post_install_message => true,
  }.merge options

  @env_shebang         = options[:env_shebang]
  @force               = options[:force]
  @install_dir         = options[:install_dir]
  @gem_home            = options[:install_dir] || Gem.dir
  @plugins_dir         = Gem.plugindir(@gem_home)
  @ignore_dependencies = options[:ignore_dependencies]
  @format_executable   = options[:format_executable]
  @wrappers            = options[:wrappers]
  @only_install_dir    = options[:only_install_dir]

  # If the user has asked for the gem to be installed in a directory that is
  # the system gem directory, then use the system bin directory, else create
  # (or use) a new bin dir under the gem_home.
  @bin_dir             = options[:bin_dir] || Gem.bindir(gem_home)
  @development         = options[:development]
  @build_root          = options[:build_root]

  @build_args = options[:build_args]

  unless @build_root.nil?
    @bin_dir = File.join(@build_root, @bin_dir.gsub(/^[a-zA-Z]:/, ""))
    @gem_home = File.join(@build_root, @gem_home.gsub(/^[a-zA-Z]:/, ""))
    @plugins_dir = File.join(@build_root, @plugins_dir.gsub(/^[a-zA-Z]:/, ""))
    alert_warning "You build with buildroot.\n  Build root: #{@build_root}\n  Bin dir: #{@bin_dir}\n  Gem home: #{@gem_home}\n  Plugins dir: #{@plugins_dir}"
  end
end

#rb_config (private)

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 973

def rb_config
  RbConfig::CONFIG
end

#ruby_install_name (private)

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 977

def ruby_install_name
  rb_config["ruby_install_name"]
end

#run_post_build_hooks

This method is for internal use only.
[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 366

def run_post_build_hooks # :nodoc:
  Gem.post_build_hooks.each do |hook|
    if hook.call(self) == false
      FileUtils.rm_rf gem_dir

      location = " at #{$1}" if hook.inspect =~ /[ @](.*:\d+)/

      message = "post-build hook#{location} failed for #{spec.full_name}"
      raise Gem::InstallError, message
    end
  end
end

#run_post_install_hooks

This method is for internal use only.
[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 379

def run_post_install_hooks # :nodoc:
  Gem.post_install_hooks.each do |hook|
    hook.call self
  end
end

#run_pre_install_hooks

This method is for internal use only.
[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 355

def run_pre_install_hooks # :nodoc:
  Gem.pre_install_hooks.each do |hook|
    if hook.call(self) == false
      location = " at #{$1}" if hook.inspect =~ /[ @](.*:\d+)/

      message = "pre-install hook#{location} failed for #{spec.full_name}"
      raise Gem::InstallError, message
    end
  end
end

#shebang(bin_file_name)

Generates a #! line for bin_file_name‘s wrapper copying arguments if necessary.

If the :custom_shebang config is set, then it is used as a template for how to create the shebang used for to run a gem’s executables.

The template supports 4 expansions:

$env    the path to the unix env utility
$ruby   the path to the currently running ruby interpreter
$exec   the path to the gem's executable
$name   the name of the gem the executable is for
[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 587

def shebang(bin_file_name)
  path = File.join gem_dir, spec.bindir, bin_file_name
  first_line = File.open(path, "rb") {|file| file.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

#spec

Lazy accessor for the installer’s spec.

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 286

def spec
  @package.spec
end

#spec_file

The location of the spec file that is installed.

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 440

def spec_file
  File.join gem_home, "specifications", "#{spec.full_name}.gemspec"
end

#unpack(directory)

Unpacks the gem into the given directory.

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 430

def unpack(directory)
  @gem_dir = directory
  extract_files
end

#verify_gem_home

This method is for internal use only.
[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 710

def verify_gem_home # :nodoc:
  FileUtils.mkdir_p gem_home, :mode => options[:dir_mode] && 0755
  raise Gem::FilePermissionError, gem_home unless File.writable?(gem_home)
end

#verify_spec

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 715

def verify_spec
  unless spec.name =~ Gem::Specification::VALID_NAME_PATTERN
    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 spec.platform.to_s =~ /\R/
    raise Gem::InstallError, "#{spec.platform} is an invalid platform"
  end

  unless spec.specification_version.to_s =~ /\A\d+\z/
    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

#windows_stub_script(bindir, bin_file_name)

return the stub script text used to launch the true Ruby script

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 804

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

#write_build_info_file

Writes the file containing the arguments for building this gem’s extensions.

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 927

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 && 0755

  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

#write_cache_file

Writes the #gem file to the cache directory

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 949

def write_cache_file
  cache_file = File.join gem_home, "cache", spec.file_name
  @package.copy_to cache_file
end

#write_default_spec

Writes the full .gemspec specification (in Ruby) to the gem home’s specifications/default directory.

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 466

def write_default_spec
  Gem.write_binary(default_spec_file, spec.to_ruby)
end

#write_spec

Writes the .gemspec specification (in Ruby) to the gem home’s specifications directory.

[ GitHub ]

  
# File 'lib/rubygems/installer.rb', line 456

def write_spec
  spec.installed_by_version = Gem.rubygems_version

  Gem.write_binary(spec_file, spec.to_ruby_for_cache)
end