# <!-- rdoc-file=ext/socket/unixserver.c -->
# UNIXServer represents a UNIX domain stream server socket.
#
class UNIXServer < UNIXSocket
  # <!--
  #   rdoc-file=ext/socket/unixserver.c
  #   - unixserver.accept => unixsocket
  # -->
  # Accepts an incoming connection. It returns a new UNIXSocket object.
  #
  #     UNIXServer.open("/tmp/sock") {|serv|
  #       UNIXSocket.open("/tmp/sock") {|c|
  #         s = serv.accept
  #         s.puts "hi"
  #         s.close
  #         p c.read #=> "hi\n"
  #       }
  #     }
  #
  def accept: () -> UNIXSocket

  # <!--
  #   rdoc-file=ext/socket/lib/socket.rb
  #   - unixserver.accept_nonblock([options]) => unixsocket
  # -->
  # Accepts an incoming connection using accept(2) after O_NONBLOCK is set for the
  # underlying file descriptor. It returns an accepted UNIXSocket for the incoming
  # connection.
  #
  # ### Example
  #     require 'socket'
  #     serv = UNIXServer.new("/tmp/sock")
  #     begin # emulate blocking accept
  #       sock = serv.accept_nonblock
  #     rescue IO::WaitReadable, Errno::EINTR
  #       IO.select([serv])
  #       retry
  #     end
  #     # sock is an accepted socket.
  #
  # Refer to Socket#accept for the exceptions that may be thrown if the call to
  # UNIXServer#accept_nonblock fails.
  #
  # UNIXServer#accept_nonblock may raise any error corresponding to accept(2)
  # failure, including Errno::EWOULDBLOCK.
  #
  # If the exception is Errno::EWOULDBLOCK, Errno::EAGAIN, Errno::ECONNABORTED or
  # Errno::EPROTO, it is extended by IO::WaitReadable. So IO::WaitReadable can be
  # used to rescue the exceptions for retrying accept_nonblock.
  #
  # By specifying a keyword argument *exception* to `false`, you can indicate that
  # accept_nonblock should not raise an IO::WaitReadable exception, but return the
  # symbol `:wait_readable` instead.
  #
  # ### See
  # *   UNIXServer#accept
  # *   Socket#accept
  #
  def accept_nonblock: (?exception: boolish) -> (UNIXSocket | :wait_readable)

  # <!--
  #   rdoc-file=ext/socket/unixserver.c
  #   - socket.listen( int ) => 0
  # -->
  # Listens for connections, using the specified `int` as the backlog. A call to
  # *listen* only applies if the `socket` is of type SOCK_STREAM or
  # SOCK_SEQPACKET.
  #
  # ### Parameter
  # *   `backlog` - the maximum length of the queue for pending connections.
  #
  # ### Example 1
  #     require 'socket'
  #     include Socket::Constants
  #     socket = Socket.new( AF_INET, SOCK_STREAM, 0 )
  #     sockaddr = Socket.pack_sockaddr_in( 2200, 'localhost' )
  #     socket.bind( sockaddr )
  #     socket.listen( 5 )
  #
  # ### Example 2 (listening on an arbitrary port, unix-based systems only):
  #     require 'socket'
  #     include Socket::Constants
  #     socket = Socket.new( AF_INET, SOCK_STREAM, 0 )
  #     socket.listen( 1 )
  #
  # ### Unix-based Exceptions
  # On unix based systems the above will work because a new `sockaddr` struct is
  # created on the address ADDR_ANY, for an arbitrary port number as handed off by
  # the kernel. It will not work on Windows, because Windows requires that the
  # `socket` is bound by calling *bind* before it can *listen*.
  #
  # If the *backlog* amount exceeds the implementation-dependent maximum queue
  # length, the implementation's maximum queue length will be used.
  #
  # On unix-based based systems the following system exceptions may be raised if
  # the call to *listen* fails:
  # *   Errno::EBADF - the *socket* argument is not a valid file descriptor
  # *   Errno::EDESTADDRREQ - the *socket* is not bound to a local address, and
  #     the protocol does not support listening on an unbound socket
  # *   Errno::EINVAL - the *socket* is already connected
  # *   Errno::ENOTSOCK - the *socket* argument does not refer to a socket
  # *   Errno::EOPNOTSUPP - the *socket* protocol does not support listen
  # *   Errno::EACCES - the calling process does not have appropriate privileges
  # *   Errno::EINVAL - the *socket* has been shut down
  # *   Errno::ENOBUFS - insufficient resources are available in the system to
  #     complete the call
  #
  # ### Windows Exceptions
  # On Windows systems the following system exceptions may be raised if the call
  # to *listen* fails:
  # *   Errno::ENETDOWN - the network is down
  # *   Errno::EADDRINUSE - the socket's local address is already in use. This
  #     usually occurs during the execution of *bind* but could be delayed if the
  #     call to *bind* was to a partially wildcard address (involving ADDR_ANY)
  #     and if a specific address needs to be committed at the time of the call to
  #     *listen*
  # *   Errno::EINPROGRESS - a Windows Sockets 1.1 call is in progress or the
  #     service provider is still processing a callback function
  # *   Errno::EINVAL - the `socket` has not been bound with a call to *bind*.
  # *   Errno::EISCONN - the `socket` is already connected
  # *   Errno::EMFILE - no more socket descriptors are available
  # *   Errno::ENOBUFS - no buffer space is available
  # *   Errno::ENOTSOC - `socket` is not a socket
  # *   Errno::EOPNOTSUPP - the referenced `socket` is not a type that supports
  #     the *listen* method
  #
  # ### See
  # *   listen manual pages on unix-based systems
  # *   listen function in Microsoft's Winsock functions reference
  #
  def listen: (Integer backlog) -> void

  # <!--
  #   rdoc-file=ext/socket/unixserver.c
  #   - unixserver.sysaccept => file_descriptor
  # -->
  # Accepts a new connection. It returns the new file descriptor which is an
  # integer.
  #
  #     UNIXServer.open("/tmp/sock") {|serv|
  #       UNIXSocket.open("/tmp/sock") {|c|
  #         fd = serv.sysaccept
  #         s = IO.new(fd)
  #         s.puts "hi"
  #         s.close
  #         p c.read #=> "hi\n"
  #       }
  #     }
  #
  def sysaccept: () -> Integer

  private

  def __accept_nonblock: (untyped) -> untyped

  # <!--
  #   rdoc-file=ext/socket/unixserver.c
  #   - UNIXServer.new(path) => unixserver
  # -->
  # Creates a new UNIX server socket bound to *path*.
  #
  #     require 'socket'
  #
  #     serv = UNIXServer.new("/tmp/sock")
  #     s = serv.accept
  #     p s.read
  #
  def initialize: (untyped) -> untyped
end
