class Gem::Resolver::InstallerSet

# File lib/rubygems/resolver/installer_set.rb, line 31
def initialize domain
  super()

  @domain = domain
  @remote = consider_remote?

  @f = Gem::SpecFetcher.fetcher

  @always_install      = []
  @ignore_dependencies = false
  @ignore_installed    = false
  @local               = {}
  @local_source        = Gem::Source::Local.new
  @remote_set          = Gem::Resolver::BestSet.new
  @specs               = {}
end

# File lib/rubygems/resolver/installer_set.rb, line 52
def add_always_install dependency
  request = Gem::Resolver::DependencyRequest.new dependency, nil

  found = find_all request

  found.delete_if { |s|
    s.version.prerelease? and not s.local?
  } unless dependency.prerelease?

  found = found.select do |s|
    Gem::Source::SpecificFile === s.source or
      Gem::Platform::RUBY == s.platform or
      Gem::Platform.local === s.platform
  end

  if found.empty? then
    exc = Gem::UnsatisfiableDependencyError.new request
    exc.errors = errors

    raise exc
  end

  newest = found.max_by do |s|
    [s.version, s.platform == Gem::Platform::RUBY ? -1 : 1]
  end

  @always_install << newest.spec
end

# File lib/rubygems/resolver/installer_set.rb, line 85
def add_local dep_name, spec, source
  @local[dep_name] = [spec, source]
end

# File lib/rubygems/resolver/installer_set.rb, line 106
def errors
  @errors + @remote_set.errors
end

# File lib/rubygems/resolver/installer_set.rb, line 114
def find_all req
  res = []

  dep  = req.dependency

  return res if @ignore_dependencies and
            @always_install.none? { |spec| dep.match? spec }

  name = dep.name

  dep.matching_specs.each do |gemspec|
    next if @always_install.any? { |spec| spec.name == gemspec.name }

    res << Gem::Resolver::InstalledSpecification.new(self, gemspec)
  end unless @ignore_installed

  if consider_local? then
    matching_local = @local.values.select do |spec, _|
      req.match? spec
    end.map do |spec, source|
      Gem::Resolver::LocalSpecification.new self, spec, source
    end

    res.concat matching_local

    begin
      if local_spec = @local_source.find_gem(name, dep.requirement) then
        res << Gem::Resolver::IndexSpecification.new(
          self, local_spec.name, local_spec.version,
          @local_source, local_spec.platform)
      end
    rescue Gem::Package::FormatError
      # ignore
    end
  end

  res.delete_if do |spec|
    spec.version.prerelease? and not dep.prerelease?
  end

  res.concat @remote_set.find_all req if consider_remote?

  res
end

# File lib/rubygems/resolver/installer_set.rb, line 159
def prefetch(reqs)
  @remote_set.prefetch(reqs) if consider_remote?
end

# File lib/rubygems/resolver/installer_set.rb, line 163
def prerelease= allow_prerelease
  super

  @remote_set.prerelease = allow_prerelease
end