linguist/samples/Ruby/formula.rb

require 'download_strategy'
require 'dependencies'
require 'formula_support'
require 'hardware'
require 'bottles'
require 'extend/fileutils'
require 'patches'
require 'compilers'

# Derive and define at least @url, see Library/Formula for examples
class Formula
  include FileUtils

  attr_reader :name, :path, :url, :version, :homepage, :specs, :downloader
  attr_reader :standard, :unstable, :head
  attr_reader :bottle_version, :bottle_url, :bottle_sha1

  # The build folder, usually in /tmp.
  # Will only be non-nil during the stage method.
  attr_reader :buildpath

  # Homebrew determines the name
  def initialize name='__UNKNOWN__', path=nil
    set_instance_variable 'homepage'
    set_instance_variable 'url'
    set_instance_variable 'bottle_version'
    set_instance_variable 'bottle_url'
    set_instance_variable 'bottle_sha1'
    set_instance_variable 'head'
    set_instance_variable 'specs'
    set_instance_variable 'standard'
    set_instance_variable 'unstable'

    if @head and (not @url or ARGV.build_head?)
      @url = @head
      @version = 'HEAD'
      @spec_to_use = @unstable
    else
      if @standard.nil?
        @spec_to_use = SoftwareSpecification.new(@url, @specs)
      else
        @spec_to_use = @standard
      end
    end

    raise "No url provided for formula #{name}" if @url.nil?
    @name = name
    validate_variable :name

    # If we got an explicit path, use that, else determine from the name
    @path = path.nil? ? self.class.path(name) : Pathname.new(path)

    # Use a provided version, if any
    set_instance_variable 'version'
    # Otherwise detect the version from the URL
    @version ||= @spec_to_use.detect_version
    # Only validate if a version was set; GitHubGistFormula needs to get
    # the URL to determine the version
    validate_variable :version if @version

    CHECKSUM_TYPES.each { |type| set_instance_variable type }

    @downloader = download_strategy.new @spec_to_use.url, name, version, @spec_to_use.specs

    @bottle_url ||= bottle_base_url + bottle_filename(self) if @bottle_sha1
  end

  # if the dir is there, but it's empty we consider it not installed
  def installed?
    return installed_prefix.children.length > 0
  rescue
    return false
  end

  def explicitly_requested?
    # `ARGV.formulae` will throw an exception if it comes up with an empty list.
    # FIXME: `ARGV.formulae` shouldn't be throwing exceptions, see issue #8823
   return false if ARGV.named.empty?
   ARGV.formulae.include? self
  end

  def linked_keg
    HOMEBREW_REPOSITORY/'Library/LinkedKegs'/@name
  end

  def installed_prefix
    head_prefix = HOMEBREW_CELLAR+@name+'HEAD'
    if @version == 'HEAD' || head_prefix.directory?
      head_prefix
    else
      prefix
    end
  end

  def prefix
    validate_variable :name
    validate_variable :version
    HOMEBREW_CELLAR+@name+@version
  end
  def rack; prefix.parent end

  def bin;     prefix+'bin'            end
  def doc;     prefix+'share/doc'+name end
  def include; prefix+'include'        end
  def info;    prefix+'share/info'     end
  def lib;     prefix+'lib'            end
  def libexec; prefix+'libexec'        end
  def man;     prefix+'share/man'      end
  def man1;    man+'man1'              end
  def man2;    man+'man2'              end
  def man3;    man+'man3'              end
  def man4;    man+'man4'              end
  def man5;    man+'man5'              end
  def man6;    man+'man6'              end
  def man7;    man+'man7'              end
  def man8;    man+'man8'              end
  def sbin;    prefix+'sbin'           end
  def share;   prefix+'share'          end

  # configuration needs to be preserved past upgrades
  def etc; HOMEBREW_PREFIX+'etc' end
  # generally we don't want var stuff inside the keg
  def var; HOMEBREW_PREFIX+'var' end

  # plist name, i.e. the name of the launchd service
  def plist_name; 'homebrew.mxcl.'+name end
  def plist_path; prefix+(plist_name+'.plist') end

  # Use the @spec_to_use to detect the download strategy.
  # Can be overriden to force a custom download strategy
  def download_strategy
    @spec_to_use.download_strategy
  end

  def cached_download
    @downloader.cached_location
  end

  # tell the user about any caveats regarding this package, return a string
  def caveats; nil end

  # any e.g. configure options for this package
  def options; [] end

  # patches are automatically applied after extracting the tarball
  # return an array of strings, or if you need a patch level other than -p1
  # return a Hash eg.
  #   {
  #     :p0 => ['http://foo.com/patch1', 'http://foo.com/patch2'],
  #     :p1 =>  'http://bar.com/patch2',
  #     :p2 => ['http://moo.com/patch5', 'http://moo.com/patch6']
  #   }
  # The final option is to return DATA, then put a diff after __END__. You
  # can still return a Hash with DATA as the value for a patch level key.
  def patches; end

  # rarely, you don't want your library symlinked into the main prefix
  # see gettext.rb for an example
  def keg_only?
    self.class.keg_only_reason || false
  end

  def fails_with? cc
    return false if self.class.cc_failures.nil?
    cc = Compiler.new(cc) unless cc.is_a? Compiler
    return self.class.cc_failures.find do |failure|
      next unless failure.compiler == cc.name
      failure.build.zero? or failure.build >= cc.build
    end
  end

  # sometimes the clean process breaks things
  # skip cleaning paths in a formula with a class method like this:
  #   skip_clean [bin+"foo", lib+"bar"]
  # redefining skip_clean? now deprecated
  def skip_clean? path
    return true if self.class.skip_clean_all?
    to_check = path.relative_path_from(prefix).to_s
    self.class.skip_clean_paths.include? to_check
  end

  # yields self with current working directory set to the uncompressed tarball
  def brew
    validate_variable :name
    validate_variable :version

    stage do
      begin
        patch
        # we allow formulas to do anything they want to the Ruby process
        # so load any deps before this point! And exit asap afterwards
        yield self
      rescue Interrupt, RuntimeError, SystemCallError => e
        puts if Interrupt === e # don't print next to the ^C
        unless ARGV.debug?
          %w(config.log CMakeCache.txt).select{|f| File.exist? f}.each do |f|
            HOMEBREW_LOGS.install f
            puts "#{f} was copied to #{HOMEBREW_LOGS}"
          end
          raise
        end
        onoe e.inspect
        puts e.backtrace

        ohai "Rescuing build..."
        if (e.was_running_configure? rescue false) and File.exist? 'config.log'
          puts "It looks like an autotools configure failed."
          puts "Gist 'config.log' and any error output when reporting an issue."
          puts
        end

        puts "When you exit this shell Homebrew will attempt to finalise the installation."
        puts "If nothing is installed or the shell exits with a non-zero error code,"
        puts "Homebrew will abort. The installation prefix is:"
        puts prefix
        interactive_shell self
      end
    end
  end

  def == b
    name == b.name
  end
  def eql? b
    self == b and self.class.equal? b.class
  end
  def hash
    name.hash
  end
  def <=> b
    name <=> b.name
  end
  def to_s
    name
  end

  # Standard parameters for CMake builds.
  # Using Build Type "None" tells cmake to use our CFLAGS,etc. settings.
  # Setting it to Release would ignore our flags.
  # Setting CMAKE_FIND_FRAMEWORK to "LAST" tells CMake to search for our
  # libraries before trying to utilize Frameworks, many of which will be from
  # 3rd party installs.
  # Note: there isn't a std_autotools variant because autotools is a lot
  # less consistent and the standard parameters are more memorable.
  def std_cmake_args
    %W[
      -DCMAKE_INSTALL_PREFIX=#{prefix}
      -DCMAKE_BUILD_TYPE=None
      -DCMAKE_FIND_FRAMEWORK=LAST
      -Wno-dev
    ]
  end

  def self.class_s name
    #remove invalid characters and then camelcase it
    name.capitalize.gsub(/[-_.\s]([a-zA-Z0-9])/) { $1.upcase } \
                   .gsub('+', 'x')
  end

  # an array of all Formula names
  def self.names
    Dir["#{HOMEBREW_REPOSITORY}/Library/Formula/*.rb"].map{ |f| File.basename f, '.rb' }.sort
  end

  # an array of all Formula, instantiated
  def self.all
    map{ |f| f }
  end
  def self.map
    rv = []
    each{ |f| rv << yield(f) }
    rv
  end
  def self.each
    names.each do |n|
      begin
        yield Formula.factory(n)
      rescue
        # Don't let one broken formula break commands. But do complain.
        onoe "Formula #{n} will not import."
      end
    end
  end

  def inspect
    name
  end

  def self.aliases
    Dir["#{HOMEBREW_REPOSITORY}/Library/Aliases/*"].map{ |f| File.basename f }.sort
  end

  def self.canonical_name name
    name = name.to_s if name.kind_of? Pathname

    formula_with_that_name = HOMEBREW_REPOSITORY+"Library/Formula/#{name}.rb"
    possible_alias = HOMEBREW_REPOSITORY+"Library/Aliases/#{name}"
    possible_cached_formula = HOMEBREW_CACHE_FORMULA+"#{name}.rb"

    if name.include? "/"
      if name =~ %r{(.+)/(.+)/(.+)}
        tapd = HOMEBREW_REPOSITORY/"Library/Taps"/"#$1-#$2".downcase
        tapd.find_formula do |relative_pathname|
          return "#{tapd}/#{relative_pathname}" if relative_pathname.stem.to_s == $3
        end if tapd.directory?
      end
      # Otherwise don't resolve paths or URLs
      name
    elsif formula_with_that_name.file? and formula_with_that_name.readable?
      name
    elsif possible_alias.file?
      possible_alias.realpath.basename('.rb').to_s
    elsif possible_cached_formula.file?
      possible_cached_formula.to_s
    else
      name
    end
  end

  def self.factory name
    # If an instance of Formula is passed, just return it
    return name if name.kind_of? Formula

    # Otherwise, convert to String in case a Pathname comes in
    name = name.to_s

    # If a URL is passed, download to the cache and install
    if name =~ %r[(https?|ftp)://]
      url = name
      name = Pathname.new(name).basename
      target_file = HOMEBREW_CACHE_FORMULA+name
      name = name.basename(".rb").to_s

      HOMEBREW_CACHE_FORMULA.mkpath
      FileUtils.rm target_file, :force => true
      curl url, '-o', target_file

      require target_file
      install_type = :from_url
    else
      name = Formula.canonical_name(name)
      # If name was a path or mapped to a cached formula
      if name.include? "/"
        require name

        # require allows filenames to drop the .rb extension, but everything else
        # in our codebase will require an exact and fullpath.
        name = "#{name}.rb" unless name =~ /\.rb$/

        path = Pathname.new(name)
        name = path.stem
        install_type = :from_path
        target_file = path.to_s
      else
        # For names, map to the path and then require
        require Formula.path(name)
        install_type = :from_name
      end
    end

    begin
      klass_name = self.class_s(name)
      klass = Object.const_get klass_name
    rescue NameError
      # TODO really this text should be encoded into the exception
      # and only shown if the UI deems it correct to show it
      onoe "class \"#{klass_name}\" expected but not found in #{name}.rb"
      puts "Double-check the name of the class in that formula."
      raise LoadError
    end

    return klass.new(name) if install_type == :from_name
    return klass.new(name, target_file)
  rescue LoadError
    raise FormulaUnavailableError.new(name)
  end

  def tap
    if path.realpath.to_s =~ %r{#{HOMEBREW_REPOSITORY}/Library/Taps/(\w+)-(\w+)}
      "#$1/#$2"
    else
      # remotely installed formula are not mxcl/master but this will do for now
      "mxcl/master"
    end
  end

  def self.path name
    HOMEBREW_REPOSITORY+"Library/Formula/#{name.downcase}.rb"
  end

  def mirrors;       self.class.mirrors or []; end

  def deps;          self.class.dependencies.deps;          end
  def external_deps; self.class.dependencies.external_deps; end

  # deps are in an installable order
  # which means if a depends on b then b will be ordered before a in this list
  def recursive_deps
    Formula.expand_deps(self).flatten.uniq
  end

  def self.expand_deps f
    f.deps.map do |dep|
      f_dep = Formula.factory dep.to_s
      expand_deps(f_dep) << f_dep
    end
  end

protected

  # Pretty titles the command and buffers stdout/stderr
  # Throws if there's an error
  def system cmd, *args
    # remove "boring" arguments so that the important ones are more likely to
    # be shown considering that we trim long ohai lines to the terminal width
    pretty_args = args.dup
    pretty_args.delete "--disable-dependency-tracking" if cmd == "./configure" and not ARGV.verbose?
    ohai "#{cmd} #{pretty_args*' '}".strip

    removed_ENV_variables = case if args.empty? then cmd.split(' ').first else cmd end
    when "xcodebuild"
      ENV.remove_cc_etc
    end

    if ARGV.verbose?
      safe_system cmd, *args
    else
      rd, wr = IO.pipe
      pid = fork do
        rd.close
        $stdout.reopen wr
        $stderr.reopen wr
        args.collect!{|arg| arg.to_s}
        exec(cmd, *args) rescue nil
        exit! 1 # never gets here unless exec threw or failed
      end
      wr.close
      out = ''
      out << rd.read until rd.eof?
      Process.wait
      unless $?.success?
        puts out
        raise
      end
    end

    removed_ENV_variables.each do |key, value|
      ENV[key] = value # ENV.kind_of? Hash  # => false
    end if removed_ENV_variables

  rescue
    raise BuildError.new(self, cmd, args, $?)
  end

public

  # For brew-fetch and others.
  def fetch
    if install_bottle? self
      downloader = CurlBottleDownloadStrategy.new bottle_url, name, version, nil
      mirror_list = []
    else
      downloader = @downloader
      # Don't attempt mirrors if this install is not pointed at a "stable" URL.
      # This can happen when options like `--HEAD` are invoked.
      mirror_list =  @spec_to_use == @standard ? mirrors : []
    end

    # Ensure the cache exists
    HOMEBREW_CACHE.mkpath

    begin
      fetched = downloader.fetch
    rescue CurlDownloadStrategyError => e
      raise e if mirror_list.empty?
      puts "Trying a mirror..."
      url, specs = mirror_list.shift.values_at :url, :specs
      downloader = download_strategy.new url, name, version, specs
      retry
    end

    return fetched, downloader
  end

  # Detect which type of checksum is being used, or nil if none
  def checksum_type
    CHECKSUM_TYPES.detect { |type| instance_variable_defined?("@#{type}") }
  end

  # For FormulaInstaller.
  def verify_download_integrity fn, *args
    require 'digest'
    if args.length != 2
      type = checksum_type || :md5
      supplied = instance_variable_get("@#{type}")
      # Convert symbol to readable string
      type = type.to_s.upcase
    else
      supplied, type = args
    end

    hasher = Digest.const_get(type)
    hash = fn.incremental_hash(hasher)

    if supplied and not supplied.empty?
      message = <<-EOF
#{type} mismatch
Expected: #{supplied}
Got: #{hash}
Archive: #{fn}
(To retry an incomplete download, remove the file above.)
EOF
      raise message unless supplied.upcase == hash.upcase
    else
      opoo "Cannot verify package integrity"
      puts "The formula did not provide a download checksum"
      puts "For your reference the #{type} is: #{hash}"
    end
  end

private

  CHECKSUM_TYPES=[:md5, :sha1, :sha256].freeze

  def stage
    fetched, downloader = fetch
    verify_download_integrity fetched if fetched.kind_of? Pathname
    mktemp do
      downloader.stage
      # Set path after the downloader changes the working folder.
      @buildpath = Pathname.pwd
      yield
      @buildpath = nil
    end
  end

  def patch
    patch_list = Patches.new(patches)
    return if patch_list.empty?

    if patch_list.external_patches?
      ohai "Downloading patches"
      patch_list.download!
    end

    ohai "Patching"
    patch_list.each do |p|
      case p.compression
        when :gzip  then safe_system "/usr/bin/gunzip",  p.compressed_filename
        when :bzip2 then safe_system "/usr/bin/bunzip2", p.compressed_filename
      end
      # -f means don't prompt the user if there are errors; just exit with non-zero status
      safe_system '/usr/bin/patch', '-f', *(p.patch_args)
    end
  end

  def validate_variable name
    v = instance_variable_get("@#{name}")
    raise "Invalid @#{name}" if v.to_s.empty? or v =~ /\s/
  end

  def set_instance_variable(type)
    return if instance_variable_defined? "@#{type}"
    class_value = self.class.send(type)
    instance_variable_set("@#{type}", class_value) if class_value
  end

  def self.method_added method
    raise 'You cannot override Formula.brew' if method == :brew
  end

  class << self
    # The methods below define the formula DSL.
    attr_reader :standard, :unstable

    def self.attr_rw(*attrs)
      attrs.each do |attr|
        class_eval %Q{
          def #{attr}(val=nil)
            val.nil? ? @#{attr} : @#{attr} = val
          end
        }
      end
    end

    attr_rw :version, :homepage, :mirrors, :specs
    attr_rw :keg_only_reason, :skip_clean_all, :cc_failures
    attr_rw :bottle_version, :bottle_url, :bottle_sha1
    attr_rw(*CHECKSUM_TYPES)

    def head val=nil, specs=nil
      return @head if val.nil?
      @unstable = SoftwareSpecification.new(val, specs)
      @head = val
      @specs = specs
    end

    def url val=nil, specs=nil
      return @url if val.nil?
      @standard = SoftwareSpecification.new(val, specs)
      @url = val
      @specs = specs
    end

    def stable &block
      raise "url and md5 must be specified in a block" unless block_given?
      instance_eval(&block) unless ARGV.build_devel? or ARGV.build_head?
    end

    def devel &block
      raise "url and md5 must be specified in a block" unless block_given?
      if ARGV.build_devel?
        @mirrors = nil # clear out mirrors from the stable release
        instance_eval(&block)
      end
    end

    def bottle url=nil, &block
      return unless block_given?

      bottle_block = Class.new do
        def self.version version
          @version = version
        end

        def self.url url
          @url = url
        end

        def self.sha1 sha1
          case sha1
          when Hash
            key, value = sha1.shift
            @sha1 = key if value == MacOS.cat
          when String
            @sha1 = sha1 if MacOS.lion?
          end
        end

        def self.data
          @version = 0 unless @version
          return @version, @url, @sha1 if @sha1 && @url
          return @version, nil, @sha1 if @sha1
        end
      end

      bottle_block.instance_eval(&block)
      @bottle_version, @bottle_url, @bottle_sha1 = bottle_block.data
    end

    def mirror val, specs=nil
      @mirrors ||= []
      @mirrors << {:url => val, :specs => specs}
      # Added the uniq after some inspection with Pry---seems `mirror` gets
      # called three times. The first two times only one copy of the input is
      # left in `@mirrors`. On the final call, two copies are present. This
      # happens with `@deps` as well. Odd.
      @mirrors.uniq!
    end

    def dependencies
      @dependencies ||= DependencyCollector.new
    end

    def depends_on dep
      dependencies.add(dep)
    end

    def skip_clean paths
      if paths == :all
        @skip_clean_all = true
        return
      end
      @skip_clean_paths ||= []
      [paths].flatten.each do |p|
        @skip_clean_paths << p.to_s unless @skip_clean_paths.include? p.to_s
      end
    end

    def skip_clean_all?
      @skip_clean_all
    end

    def skip_clean_paths
      @skip_clean_paths or []
    end

    def keg_only reason, explanation=nil
      @keg_only_reason = KegOnlyReason.new(reason, explanation.to_s.chomp)
    end

    def fails_with compiler, &block
      @cc_failures ||= CompilerFailures.new
      @cc_failures << if block_given?
        CompilerFailure.new(compiler, &block)
      else
        CompilerFailure.new(compiler)
      end
    end
  end
end

require 'formula_specialties'