class Gem::DependencyInstaller

# File lib/rubygems/dependency_installer.rb, line 59
def initialize(options = {})
  @install_dir = options[:install_dir] || Gem.dir

  if options[:install_dir] then
    # HACK shouldn't change the global settings, needed for -i behavior
    # maybe move to the install command?  See also github #442
    Gem::Specification.dirs = @install_dir
  end

  options = DEFAULT_OPTIONS.merge options

  @bin_dir             = options[:bin_dir]
  @dev_shallow         = options[:dev_shallow]
  @development         = options[:development]
  @document            = options[:document]
  @domain              = options[:domain]
  @env_shebang         = options[:env_shebang]
  @force               = options[:force]
  @format_executable   = options[:format_executable]
  @ignore_dependencies = options[:ignore_dependencies]
  @prerelease          = options[:prerelease]
  @security_policy     = options[:security_policy]
  @user_install        = options[:user_install]
  @wrappers            = options[:wrappers]
  @build_args          = options[:build_args]
  @build_docs_in_background = options[:build_docs_in_background]

  # Indicates that we should not try to update any deps unless
  # we absolutely must.
  @minimal_deps        = options[:minimal_deps]

  @available      = nil
  @installed_gems = []
  @toplevel_specs = nil

  @cache_dir = options[:cache_dir] || @install_dir

  # Set with any errors that SpecFetcher finds while search through
  # gemspecs for a dep
  @errors = nil
end

# File lib/rubygems/dependency_installer.rb, line 217
def add_found_dependencies to_do, dependency_list
  seen = {}
  dependencies = Hash.new { |h, name| h[name] = Gem::Dependency.new name }

  until to_do.empty? do
    spec = to_do.shift

    # HACK why is spec nil?
    next if spec.nil? or seen[spec.name]
    seen[spec.name] = true

    deps = spec.runtime_dependencies

    if @development
      if @dev_shallow
        if @toplevel_specs.include? spec.full_name
          deps |= spec.development_dependencies
        end
      else
        deps |= spec.development_dependencies
      end
    end

    deps.each do |dep|
      dependencies[dep.name] = dependencies[dep.name].merge dep

      if @minimal_deps
        next if Gem::Specification.any? do |installed_spec|
                  dep.name == installed_spec.name and
                    dep.requirement.satisfied_by? installed_spec.version
                end
      end

      results = find_gems_with_sources(dep)

      results.sorted.each do |t|
        to_do.push t.spec
      end

      results.remove_installed! dep

      @available << results
      results.inject_into_list dependency_list
    end
  end

  dependency_list.remove_specs_unsatisfied_by dependencies
end

# File lib/rubygems/dependency_installer.rb, line 123
def consider_local?
  @domain == :both or @domain == :local
end

# File lib/rubygems/dependency_installer.rb, line 131
def consider_remote?
  @domain == :both or @domain == :remote
end

# File lib/rubygems/dependency_installer.rb, line 141
def find_gems_with_sources(dep)
  set = Gem::AvailableSet.new

  if consider_local?
    sl = Gem::Source::Local.new

    if spec = sl.find_gem(dep.name)
      if dep.matches_spec? spec
        set.add spec, sl
      end
    end
  end

  if consider_remote?
    begin
      found, errors = Gem::SpecFetcher.fetcher.spec_for_dependency dep

      if @errors
        @errors += errors
      else
        @errors = errors
      end

      set << found

    rescue Gem::RemoteFetcher::FetchError => e
      # FIX if there is a problem talking to the network, we either need to always tell
      # the user (no really_verbose) or fail hard, not silently tell them that we just
      # couldn't find their requested gem.
      if Gem.configuration.really_verbose then
        say "Error fetching remote data:\t\t#{e.message}"
        say "Falling back to local-only install"
      end
      @domain = :local
    end
  end

  set
end

# File lib/rubygems/dependency_installer.rb, line 271
def find_spec_by_name_and_version(gem_name,
                                  version = Gem::Requirement.default,
                                  prerelease = false)

  set = Gem::AvailableSet.new

  if consider_local?
    if gem_name =~ /\.gem$/ and File.file? gem_name then
      src = Gem::Source::SpecificFile.new(gem_name)
      set.add src.spec, src
    elsif gem_name =~ /\.gem$/ then
      Dir[gem_name].each do |name|
        begin
          src = Gem::Source::SpecificFile.new name
          set.add src.spec, src
        rescue Gem::Package::FormatError
        end
      end
    else
      local = Gem::Source::Local.new

      if s = local.find_gem(gem_name, version)
        set.add s, local
      end
    end
  end

  if set.empty?
    dep = Gem::Dependency.new gem_name, version
    # HACK Dependency objects should be immutable
    dep.prerelease = true if prerelease

    set = find_gems_with_sources(dep)
    set.match_platform!
  end

  if set.empty?
    raise Gem::SpecificGemNotFoundException.new(gem_name, version, @errors)
  end

  @available = set
end

# File lib/rubygems/dependency_installer.rb, line 185
def gather_dependencies
  specs = @available.all_specs

  # these gems were listed by the user, always install them
  keep_names = specs.map { |spec| spec.full_name }

  if @dev_shallow
    @toplevel_specs = keep_names
  end

  dependency_list = Gem::DependencyList.new @development
  dependency_list.add(*specs)
  to_do = specs.dup
  add_found_dependencies to_do, dependency_list unless @ignore_dependencies

  # REFACTOR maybe abstract away using Gem::Specification.include? so
  # that this isn't dependent only on the currently installed gems
  dependency_list.specs.reject! { |spec|
    not keep_names.include?(spec.full_name) and
    Gem::Specification.include?(spec)
  }

  unless dependency_list.ok? or @ignore_dependencies or @force then
    reason = dependency_list.why_not_ok?.map { |k,v|
      "#{k} requires #{v.join(", ")}"
    }.join("; ")
    raise Gem::DependencyError, "Unable to resolve dependencies: #{reason}"
  end

  @gems_to_install = dependency_list.dependency_order.reverse
end

# File lib/rubygems/dependency_installer.rb, line 396
def in_background what
  fork_happened = false
  if @build_docs_in_background and Process.respond_to?(:fork)
    begin
      Process.fork do
        yield
      end
      fork_happened = true
      say "#{what} in a background process."
    rescue NotImplementedError
    end
  end
  yield unless fork_happened
end

# File lib/rubygems/dependency_installer.rb, line 328
def install dep_or_name, version = Gem::Requirement.default
  available_set_for dep_or_name, version

  @installed_gems = []

  gather_dependencies

  # REFACTOR is the last gem always the one that the user requested?
  # This code assumes that but is that actually validated by the code?

  last = @gems_to_install.size - 1
  @gems_to_install.each_with_index do |spec, index|
    # REFACTOR more current spec set hardcoding, should be abstracted?
    next if Gem::Specification.include?(spec) and index != last

    # TODO: make this sorta_verbose so other users can benefit from it
    say "Installing gem #{spec.full_name}" if Gem.configuration.really_verbose

    source = @available.source_for spec

    begin
      # REFACTOR make the fetcher to use configurable
      local_gem_path = source.download spec, @cache_dir
    rescue Gem::RemoteFetcher::FetchError
      # TODO I doubt all fetch errors are recoverable, we should at least
      # report the errors probably.
      next if @force
      raise
    end

    if @development
      if @dev_shallow
        is_dev = @toplevel_specs.include? spec.full_name
      else
        is_dev = true
      end
    end

    inst = Gem::Installer.new local_gem_path,
                              :bin_dir             => @bin_dir,
                              :development         => is_dev,
                              :env_shebang         => @env_shebang,
                              :force               => @force,
                              :format_executable   => @format_executable,
                              :ignore_dependencies => @ignore_dependencies,
                              :install_dir         => @install_dir,
                              :security_policy     => @security_policy,
                              :user_install        => @user_install,
                              :wrappers            => @wrappers,
                              :build_args          => @build_args

    spec = inst.install

    @installed_gems << spec
  end

  # Since this is currently only called for docs, we can be lazy and just say
  # it's documentation. Ideally the hook adder could decide whether to be in
  # the background or not, and what to call it.
  in_background "Installing documentation" do
    Gem.done_installing_hooks.each do |hook|
      hook.call self, @installed_gems
    end
  end unless Gem.done_installing_hooks.empty?

  @installed_gems
end