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

Gem::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 Gem.pre_install and Gem.post_install for details.

Namespace
Methods
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B
D
E
F
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I
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P
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V
W
Included Modules

Constants

ENV_PATHS = %w[/usr/bin/env /bin/env].freeze
 

Paths where env(1) might live. Some systems are broken and have it in /bin

Attributes

[W] exec_format

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”.
[RW] path_warning

True if we’ve warned about PATH not including Gem.bindir
[R] bin_dir

The directory a gem’s executables will be installed into
[R] gem_home

The gem repository the gem will be installed into
[R] options

The options passed when the Gem::Installer was instantiated.
[R] package

The gem package instance.

Class Public methods

at(path, options = {})

Construct an installer object for the gem file located at path

Source: show | on GitHub 

# File ruby/lib/rubygems/installer.rb, line 112
def self.at(path, options = {})
  security_policy = options[:security_policy]
  package = Gem::Package.new path, security_policy
  new package, options
end

exec_format()

Defaults to use Ruby’s program prefix and suffix.

Source: show | on GitHub 

# File ruby/lib/rubygems/installer.rb, line 104
def exec_format
  @exec_format ||= Gem.default_exec_format
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)

Source: show | on GitHub 

# File ruby/lib/rubygems/installer.rb, line 150
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 ‘Gem::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.

Source: show | on GitHub 

# File ruby/lib/rubygems/installer.rb, line 81
def inherited(klass)
  if klass.name == "Bundler::RubyGemsGemInstaller"
    require "rubygems/command"
  end

  super(klass)
end

new(package, options={})

Constructs an Installer instance that will install the gem at package which can either be a path or an instance of Gem::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 Gem::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

Source: show | on GitHub 

# File ruby/lib/rubygems/installer.rb, line 180
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 @gem_home == Gem.user_dir
    # If we get here, then one of the following likely happened:
    # - `--user-install` was specified
    # - `Gem::PathSupport#home` fell back to `Gem.user_dir`
    # - GEM_HOME was manually set to `Gem.user_dir`

    check_that_user_bin_dir_is_in_path
  end
end

Instance Public methods

app_script_text(bin_file_name)

Return the text for an application file.

Source: show | on GitHub 

# File ruby/lib/rubygems/installer.rb, line 757
  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_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

build_extensions()

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

Source: show | on GitHub 

# File ruby/lib/rubygems/installer.rb, line 849
def build_extensions
  builder = Gem::Ext::Builder.new spec, build_args

  builder.build_extensions
end

default_spec_file()

The location of the default spec file for default gems.

Source: show | on GitHub 

# File ruby/lib/rubygems/installer.rb, line 450
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.

Source: show | on GitHub 

# File ruby/lib/rubygems/installer.rb, line 890
def dir
  gem_dir.to_s
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

Gem::Specification

dependency

Gem::Dependency

Source: show | on GitHub 

# File ruby/lib/rubygems/installer.rb, line 412
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 Gem::Specification written out for this gem is loadable upon installation.

Source: show | on GitHub 

# File ruby/lib/rubygems/installer.rb, line 635
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

explicit_version_requirement(name)

Source: show | on GitHub 

# File ruby/lib/rubygems/installer.rb, line 800
  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.

Source: show | on GitHub 

# File ruby/lib/rubygems/installer.rb, line 869
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.

Source: show | on GitHub 

# File ruby/lib/rubygems/installer.rb, line 860
def extract_files
  @package.extract_files gem_dir
end

formatted_program_filename(filename)

Prefix and suffix the program filename the same as ruby.

Source: show | on GitHub 

# File ruby/lib/rubygems/installer.rb, line 876
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.

Source: show | on GitHub 

# File ruby/lib/rubygems/installer.rb, line 897
def gem
  @package.gem.path
end

gem_dir()

Lazy accessor for the spec’s gem directory.

Source: show | on GitHub 

# File ruby/lib/rubygems/installer.rb, line 283
def gem_dir
  @gem_dir ||= File.join(gem_home, "gems", spec.full_name)
end

gemdeps_load(name)

Source: show | on GitHub 

# File ruby/lib/rubygems/installer.rb, line 791
  def gemdeps_load(name)
    return "" if name == "bundler"

    <<-TEXT

Gem.use_gemdeps
TEXT
  end

generate_bin_script(filename, bindir)

Creates the scripts to run the applications in the gem.

Source: show | on GitHub 

# File ruby/lib/rubygems/installer.rb, line 539
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", 0o755 do |file|
    file.print app_script_text(filename)
    file.chmod(options[:prog_mode] || 0o755)
  end

  verbose bin_script_path

  generate_windows_script filename, bindir
end

Creates the symlinks to run the applications in the gem. Moves the symlink if the gem being installed has a newer version.

Source: show | on GitHub

generate_windows_script(filename, bindir)

Creates windows .bat files for easy running of commands

Source: show | on GitHub 

# File ruby/lib/rubygems/installer.rb, line 478
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 Gem::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

Source: show | on GitHub 

# File ruby/lib/rubygems/installer.rb, line 305
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 && 0o755

  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) 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

installation_satisfies_dependency?(dependency)

True if the gems in the system satisfy dependency.

Source: show | on GitHub 

# File ruby/lib/rubygems/installer.rb, line 422
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.

Source: show | on GitHub 

# File ruby/lib/rubygems/installer.rb, line 392
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

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.

Source: show | on GitHub 

# File ruby/lib/rubygems/installer.rb, line 910
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

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

Source: show | on GitHub 

# File ruby/lib/rubygems/installer.rb, line 593
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

spec()

Lazy accessor for the installer’s spec.

Source: show | on GitHub 

# File ruby/lib/rubygems/installer.rb, line 290
def spec
  @package.spec
end

spec_file()

The location of the spec file that is installed.

Source: show | on GitHub 

# File ruby/lib/rubygems/installer.rb, line 442
def spec_file
  File.join gem_home, "specifications", "#{spec.full_name}.gemspec"
end

unpack(directory)

Unpacks the gem into the given directory.

Source: show | on GitHub 

# File ruby/lib/rubygems/installer.rb, line 432
def unpack(directory)
  @gem_dir = directory
  extract_files
end

verify_spec()

Source: show | on GitHub 

# File ruby/lib/rubygems/installer.rb, line 724
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

windows_stub_script(bindir, bin_file_name)

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

Source: show | on GitHub 

# File ruby/lib/rubygems/installer.rb, line 813
  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.

Source: show | on GitHub 

# File ruby/lib/rubygems/installer.rb, line 936
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

write_cache_file()

Writes the .gem file to the cache directory

Source: show | on GitHub 

# File ruby/lib/rubygems/installer.rb, line 958
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.

In contrast to write_spec, this keeps file lists, so the ‘gem contents` command works.

Source: show | on GitHub 

# File ruby/lib/rubygems/installer.rb, line 471
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.

Source: show | on GitHub 

# File ruby/lib/rubygems/installer.rb, line 458
def write_spec
  spec.installed_by_version = Gem.rubygems_version

  Gem.write_binary(spec_file, spec.to_ruby_for_cache)
end