class Resolv::DNS

# File lib/resolv.rb, line 335
def initialize(config_info=nil)
  @mutex = Thread::Mutex.new
  @config = Config.new(config_info)
  @initialized = nil
end

# File lib/resolv.rb, line 298
def self.open(*args)
  dns = new(*args)
  return dns unless block_given?
  begin
    yield dns
  ensure
    dns.close
  end
end

# File lib/resolv.rb, line 369
def close
  @mutex.synchronize {
    if @initialized
      @initialized = false
    end
  }
end

# File lib/resolv.rb, line 407
def each_address(name)
  if use_ipv6?
    each_resource(name, Resource::IN::AAAA) {|resource| yield resource.address}
  end
  each_resource(name, Resource::IN::A) {|resource| yield resource.address}
end

# File lib/resolv.rb, line 461
def each_name(address)
  case address
  when Name
    ptr = address
  when IPv4, IPv6
    ptr = address.to_name
  when IPv4::Regex
    ptr = IPv4.create(address).to_name
  when IPv6::Regex
    ptr = IPv6.create(address).to_name
  else
    raise ResolvError.new("cannot interpret as address: #{address}")
  end
  each_resource(ptr, Resource::IN::PTR) {|resource| yield resource.name}
end

# File lib/resolv.rb, line 519
def each_resource(name, typeclass, &proc)
  fetch_resource(name, typeclass) {|reply, reply_name|
    extract_resources(reply, reply_name, typeclass, &proc)
  }
end

# File lib/resolv.rb, line 525
def fetch_resource(name, typeclass)
  lazy_initialize
  truncated = {}
  requesters = {}
  udp_requester = begin
    make_udp_requester
  rescue Errno::EACCES
    # fall back to TCP
  end
  senders = {}

  begin
    @config.resolv(name) do |candidate, tout, nameserver, port|
      msg = Message.new
      msg.rd = 1
      msg.add_question(candidate, typeclass)

      requester = requesters.fetch([nameserver, port]) do
        if !truncated[candidate] && udp_requester
          udp_requester
        else
          requesters[[nameserver, port]] = make_tcp_requester(nameserver, port)
        end
      end

      unless sender = senders[[candidate, requester, nameserver, port]]
        sender = requester.sender(msg, candidate, nameserver, port)
        next if !sender
        senders[[candidate, requester, nameserver, port]] = sender
      end
      reply, reply_name = requester.request(sender, tout)
      case reply.rcode
      when RCode::NoError
        if reply.tc == 1 and not Requester::TCP === requester
          # Retry via TCP:
          truncated[candidate] = true
          redo
        else
          yield(reply, reply_name)
        end
        return
      when RCode::NXDomain
        raise Config::NXDomain.new(reply_name.to_s)
      else
        raise Config::OtherResolvError.new(reply_name.to_s)
      end
    end
  ensure
    udp_requester&.close
    requesters.each_value { |requester| requester&.close }
  end
end

# File lib/resolv.rb, line 383
def getaddress(name)
  each_address(name) {|address| return address}
  raise ResolvError.new("DNS result has no information for #{name}")
end

# File lib/resolv.rb, line 394
def getaddresses(name)
  ret = []
  each_address(name) {|address| ret << address}
  return ret
end

# File lib/resolv.rb, line 437
def getname(address)
  each_name(address) {|name| return name}
  raise ResolvError.new("DNS result has no information for #{address}")
end

# File lib/resolv.rb, line 448
def getnames(address)
  ret = []
  each_name(address) {|name| ret << name}
  return ret
end

# File lib/resolv.rb, line 500
def getresource(name, typeclass)
  each_resource(name, typeclass) {|resource| return resource}
  raise ResolvError.new("DNS result has no information for #{name}")
end

# File lib/resolv.rb, line 509
def getresources(name, typeclass)
  ret = []
  each_resource(name, typeclass) {|resource| ret << resource}
  return ret
end

# File lib/resolv.rb, line 352
def timeouts=(values)
  @config.timeouts = values
end