text: import errno
  import os
  import socket
  import sys
  import time
  import warnings
  
  import eventlet
  from eventlet.hubs import trampoline, notify_opened, IOClosed
  from eventlet.support import get_errno
  import six
  
  __all__ = [
      'GreenSocket', '_GLOBAL_DEFAULT_TIMEOUT', 'set_nonblocking',
      'SOCKET_BLOCKING', 'SOCKET_CLOSED', 'CONNECT_ERR', 'CONNECT_SUCCESS',
      'shutdown_safe', 'SSL',
      'socket_timeout',
  ]
  
  BUFFER_SIZE = 4096
  CONNECT_ERR = set((errno.EINPROGRESS, errno.EALREADY, errno.EWOULDBLOCK))
  CONNECT_SUCCESS = set((0, errno.EISCONN))
  if sys.platform[:3] == "win":
      CONNECT_ERR.add(errno.WSAEINVAL)   # Bug 67
  
  if six.PY2:
      _python2_fileobject = socket._fileobject
  
  _original_socket = eventlet.patcher.original('socket').socket
  
  
  socket_timeout = eventlet.timeout.wrap_is_timeout(socket.timeout)
  
  
  def socket_connect(descriptor, address):
      """
      Attempts to connect to the address, returns the descriptor if it succeeds,
      returns None if it needs to trampoline, and raises any exceptions.
      """
      err = descriptor.connect_ex(address)
      if err in CONNECT_ERR:
          return None
      if err not in CONNECT_SUCCESS:
          raise socket.error(err, errno.errorcode[err])
      return descriptor
  
  
  def socket_checkerr(descriptor):
      err = descriptor.getsockopt(socket.SOL_SOCKET, socket.SO_ERROR)
      if err not in CONNECT_SUCCESS:
          raise socket.error(err, errno.errorcode[err])
  
  
  def socket_accept(descriptor):
      """
      Attempts to accept() on the descriptor, returns a client,address tuple
      if it succeeds; returns None if it needs to trampoline, and raises
      any exceptions.
      """
      try:
          return descriptor.accept()
      except socket.error as e:
          if get_errno(e) == errno.EWOULDBLOCK:
              return None
          raise
  
  
  if sys.platform[:3] == "win":
      # winsock sometimes throws ENOTCONN
      SOCKET_BLOCKING = set((errno.EAGAIN, errno.EWOULDBLOCK,))
      SOCKET_CLOSED = set((errno.ECONNRESET, errno.ENOTCONN, errno.ESHUTDOWN))
  else:
      # oddly, on linux/darwin, an unconnected socket is expected to block,
      # so we treat ENOTCONN the same as EWOULDBLOCK
      SOCKET_BLOCKING = set((errno.EAGAIN, errno.EWOULDBLOCK, errno.ENOTCONN))
      SOCKET_CLOSED = set((errno.ECONNRESET, errno.ESHUTDOWN, errno.EPIPE))
  
  
  def set_nonblocking(fd):
      """
      Sets the descriptor to be nonblocking.  Works on many file-like
      objects as well as sockets.  Only sockets can be nonblocking on
      Windows, however.
      """
      try:
          setblocking = fd.setblocking
      except AttributeError:
          # fd has no setblocking() method. It could be that this version of
          # Python predates socket.setblocking(). In that case, we can still set
          # the flag "by hand" on the underlying OS fileno using the fcntl
          # module.
          try:
              import fcntl
          except ImportError:
              # Whoops, Windows has no fcntl module. This might not be a socket
              # at all, but rather a file-like object with no setblocking()
              # method. In particular, on Windows, pipes don't support
              # non-blocking I/O and therefore don't have that method. Which
              # means fcntl wouldn't help even if we could load it.
              raise NotImplementedError("set_nonblocking() on a file object "
                                        "with no setblocking() method "
                                        "(Windows pipes don't support non-blocking I/O)")
          # We managed to import fcntl.
          fileno = fd.fileno()
          orig_flags = fcntl.fcntl(fileno, fcntl.F_GETFL)
          new_flags = orig_flags | os.O_NONBLOCK
          if new_flags != orig_flags:
              fcntl.fcntl(fileno, fcntl.F_SETFL, new_flags)
      else:
          # socket supports setblocking()
          setblocking(0)
  
  
  try:
      from socket import _GLOBAL_DEFAULT_TIMEOUT
  except ImportError:
      _GLOBAL_DEFAULT_TIMEOUT = object()
  
  
  class GreenSocket(object):
      """
      Green version of socket.socket class, that is intended to be 100%
      API-compatible.
  
      It also recognizes the keyword parameter, 'set_nonblocking=True'.
      Pass False to indicate that socket is already in non-blocking mode
      to save syscalls.
      """
  
      # This placeholder is to prevent __getattr__ from creating an infinite call loop
      fd = None
  
      def __init__(self, family=socket.AF_INET, *args, **kwargs):
          should_set_nonblocking = kwargs.pop('set_nonblocking', True)
          if isinstance(family, six.integer_types):
              fd = _original_socket(family, *args, **kwargs)
              # Notify the hub that this is a newly-opened socket.
              notify_opened(fd.fileno())
          else:
              fd = family
  
          # import timeout from other socket, if it was there
          try:
              self._timeout = fd.gettimeout() or socket.getdefaulttimeout()
          except AttributeError:
              self._timeout = socket.getdefaulttimeout()
  
          # Filter fd.fileno() != -1 so that won't call set non-blocking on
          # closed socket
          if should_set_nonblocking and fd.fileno() != -1:
              set_nonblocking(fd)
          self.fd = fd
          # when client calls setblocking(0) or settimeout(0) the socket must
          # act non-blocking
          self.act_non_blocking = False
  
          # Copy some attributes from underlying real socket.
          # This is the easiest way that i found to fix
          # https://bitbucket.org/eventlet/eventlet/issue/136
          # Only `getsockopt` is required to fix that issue, others
          # are just premature optimization to save __getattr__ call.
          self.bind = fd.bind
          self.close = fd.close
          self.fileno = fd.fileno
          self.getsockname = fd.getsockname
          self.getsockopt = fd.getsockopt
          self.listen = fd.listen
          self.setsockopt = fd.setsockopt
          self.shutdown = fd.shutdown
          self._closed = False
  
      @property
      def _sock(self):
          return self
  
      if six.PY3:
          def _get_io_refs(self):
              return self.fd._io_refs
  
          def _set_io_refs(self, value):
              self.fd._io_refs = value
  
          _io_refs = property(_get_io_refs, _set_io_refs)
  
      # Forward unknown attributes to fd, cache the value for future use.
      # I do not see any simple attribute which could be changed
      # so caching everything in self is fine.
      # If we find such attributes - only attributes having __get__ might be cached.
      # For now - I do not want to complicate it.
      def __getattr__(self, name):
          if self.fd is None:
              raise AttributeError(name)
          attr = getattr(self.fd, name)
          setattr(self, name, attr)
          return attr
  
      def _trampoline(self, fd, read=False, write=False, timeout=None, timeout_exc=None):
          """ We need to trampoline via the event hub.
              We catch any signal back from the hub indicating that the operation we
              were waiting on was associated with a filehandle that's since been
              invalidated.
          """
          if self._closed:
              # If we did any logging, alerting to a second trampoline attempt on a closed
              # socket here would be useful.
              raise IOClosed()
          try:
              return trampoline(fd, read=read, write=write, timeout=timeout,
                                timeout_exc=timeout_exc,
                                mark_as_closed=self._mark_as_closed)
          except IOClosed:
              # This socket's been obsoleted. De-fang it.
              self._mark_as_closed()
              raise
  
      def accept(self):
          if self.act_non_blocking:
              res = self.fd.accept()
              notify_opened(res[0].fileno())
              return res
          fd = self.fd
          _timeout_exc = socket_timeout('timed out')
          while True:
              res = socket_accept(fd)
              if res is not None:
                  client, addr = res
                  notify_opened(client.fileno())
                  set_nonblocking(client)
                  return type(self)(client), addr
              self._trampoline(fd, read=True, timeout=self.gettimeout(), timeout_exc=_timeout_exc)
  
      def _mark_as_closed(self):
          """ Mark this socket as being closed """
          self._closed = True
  
      def __del__(self):
          # This is in case self.close is not assigned yet (currently the constructor does it)
          close = getattr(self, 'close', None)
          if close is not None:
              close()
  
      def connect(self, address):
          if self.act_non_blocking:
              return self.fd.connect(address)
          fd = self.fd
          _timeout_exc = socket_timeout('timed out')
          if self.gettimeout() is None:
              while not socket_connect(fd, address):
                  try:
                      self._trampoline(fd, write=True)
                  except IOClosed:
                      raise socket.error(errno.EBADFD)
                  socket_checkerr(fd)
          else:
              end = time.time() + self.gettimeout()
              while True:
                  if socket_connect(fd, address):
                      return
                  if time.time() >= end:
                      raise _timeout_exc
                  timeout = end - time.time()
                  try:
                      self._trampoline(fd, write=True, timeout=timeout, timeout_exc=_timeout_exc)
                  except IOClosed:
                      # ... we need some workable errno here.
                      raise socket.error(errno.EBADFD)
                  socket_checkerr(fd)
  
      def connect_ex(self, address):
          if self.act_non_blocking:
              return self.fd.connect_ex(address)
          fd = self.fd
          if self.gettimeout() is None:
              while not socket_connect(fd, address):
                  try:
                      self._trampoline(fd, write=True)
                      socket_checkerr(fd)
                  except socket.error as ex:
                      return get_errno(ex)
                  except IOClosed:
                      return errno.EBADFD
                  return 0
          else:
              end = time.time() + self.gettimeout()
              timeout_exc = socket.timeout(errno.EAGAIN)
              while True:
                  try:
                      if socket_connect(fd, address):
                          return 0
                      if time.time() >= end:
                          raise timeout_exc
                      self._trampoline(fd, write=True, timeout=end - time.time(),
                                       timeout_exc=timeout_exc)
                      socket_checkerr(fd)
                  except socket.error as ex:
                      return get_errno(ex)
                  except IOClosed:
                      return errno.EBADFD
                  return 0
  
      def dup(self, *args, **kw):
          sock = self.fd.dup(*args, **kw)
          newsock = type(self)(sock, set_nonblocking=False)
          newsock.settimeout(self.gettimeout())
          return newsock
  
      if six.PY3:
          def makefile(self, *args, **kwargs):
              return _original_socket.makefile(self, *args, **kwargs)
      else:
          def makefile(self, *args, **kwargs):
              dupped = self.dup()
              res = _python2_fileobject(dupped, *args, **kwargs)
              if hasattr(dupped, "_drop"):
                  dupped._drop()
                  # Making the close function of dupped None so that when garbage collector
                  # kicks in and tries to call del, which will ultimately call close, _drop
                  # doesn't get called on dupped twice as it has been already explicitly called in
                  # previous line
                  dupped.close = None
              return res
  
      def makeGreenFile(self, *args, **kw):
          warnings.warn("makeGreenFile has been deprecated, please use "
                        "makefile instead", DeprecationWarning, stacklevel=2)
          return self.makefile(*args, **kw)
  
      def _read_trampoline(self):
          self._trampoline(
              self.fd,
              read=True,
              timeout=self.gettimeout(),
              timeout_exc=socket_timeout('timed out'))
  
      def _recv_loop(self, recv_meth, empty_val, *args):
          if self.act_non_blocking:
              return recv_meth(*args)
  
          while True:
              try:
                  # recv: bufsize=0?
                  # recv_into: buffer is empty?
                  # This is needed because behind the scenes we use sockets in
                  # nonblocking mode and builtin recv* methods. Attempting to read
                  # 0 bytes from a nonblocking socket using a builtin recv* method
                  # does not raise a timeout exception. Since we're simulating
                  # a blocking socket here we need to produce a timeout exception
                  # if needed, hence the call to trampoline.
                  if not args[0]:
                      self._read_trampoline()
                  return recv_meth(*args)
              except socket.error as e:
                  if get_errno(e) in SOCKET_BLOCKING:
                      pass
                  elif get_errno(e) in SOCKET_CLOSED:
                      return empty_val
                  else:
                      raise
  
              try:
                  self._read_trampoline()
              except IOClosed as e:
                  # Perhaps we should return '' instead?
                  raise EOFError()
  
      def recv(self, bufsize, flags=0):
          return self._recv_loop(self.fd.recv, b'', bufsize, flags)
  
      def recvfrom(self, bufsize, flags=0):
          return self._recv_loop(self.fd.recvfrom, b'', bufsize, flags)
  
      def recv_into(self, buffer, nbytes=0, flags=0):
          return self._recv_loop(self.fd.recv_into, 0, buffer, nbytes, flags)
  
      def recvfrom_into(self, buffer, nbytes=0, flags=0):
          return self._recv_loop(self.fd.recvfrom_into, 0, buffer, nbytes, flags)
  
      def _send_loop(self, send_method, data, *args):
          if self.act_non_blocking:
              return send_method(data, *args)
  
          _timeout_exc = socket_timeout('timed out')
          while True:
              try:
                  return send_method(data, *args)
              except socket.error as e:
                  eno = get_errno(e)
                  if eno == errno.ENOTCONN or eno not in SOCKET_BLOCKING:
                      raise
  
              try:
                  self._trampoline(self.fd, write=True, timeout=self.gettimeout(),
                                   timeout_exc=_timeout_exc)
              except IOClosed:
                  raise socket.error(errno.ECONNRESET, 'Connection closed by another thread')
  
      def send(self, data, flags=0):
          return self._send_loop(self.fd.send, data, flags)
  
      def sendto(self, data, *args):
          return self._send_loop(self.fd.sendto, data, *args)
  
      def sendall(self, data, flags=0):
          tail = self.send(data, flags)
          len_data = len(data)
          while tail < len_data:
              tail += self.send(data[tail:], flags)
  
      def setblocking(self, flag):
          if flag:
              self.act_non_blocking = False
              self._timeout = None
          else:
              self.act_non_blocking = True
              self._timeout = 0.0
  
      def settimeout(self, howlong):
          if howlong is None or howlong == _GLOBAL_DEFAULT_TIMEOUT:
              self.setblocking(True)
              return
          try:
              f = howlong.__float__
          except AttributeError:
              raise TypeError('a float is required')
          howlong = f()
          if howlong < 0.0:
              raise ValueError('Timeout value out of range')
          if howlong == 0.0:
              self.act_non_blocking = True
              self._timeout = 0.0
          else:
              self.act_non_blocking = False
              self._timeout = howlong
  
      def gettimeout(self):
          return self._timeout
  
      def __enter__(self):
          return self
  
      def __exit__(self, *args):
          self.close()
  
      if "__pypy__" in sys.builtin_module_names:
          def _reuse(self):
              getattr(self.fd, '_sock', self.fd)._reuse()
  
          def _drop(self):
              getattr(self.fd, '_sock', self.fd)._drop()
  
  
  def _operation_on_closed_file(*args, **kwargs):
      raise ValueError("I/O operation on closed file")
  
  
  greenpipe_doc = """
      GreenPipe is a cooperative replacement for file class.
      It will cooperate on pipes. It will block on regular file.
      Differences from file class:
      - mode is r/w property. Should re r/o
      - encoding property not implemented
      - write/writelines will not raise TypeError exception when non-string data is written
        it will write str(data) instead
      - Universal new lines are not supported and newlines property not implementeded
      - file argument can be descriptor, file name or file object.
      """
  
  # import SSL module here so we can refer to greenio.SSL.exceptionclass
  try:
      from OpenSSL import SSL
  except ImportError:
      # pyOpenSSL not installed, define exceptions anyway for convenience
      class SSL(object):
          class WantWriteError(Exception):
              pass
  
          class WantReadError(Exception):
              pass
  
          class ZeroReturnError(Exception):
              pass
  
          class SysCallError(Exception):
              pass
  
  
  def shutdown_safe(sock):
      """Shuts down the socket. This is a convenience method for
      code that wants to gracefully handle regular sockets, SSL.Connection
      sockets from PyOpenSSL and ssl.SSLSocket objects from Python 2.7 interchangeably.
      Both types of ssl socket require a shutdown() before close,
      but they have different arity on their shutdown method.
  
      Regular sockets don't need a shutdown before close, but it doesn't hurt.
      """
      try:
          try:
              # socket, ssl.SSLSocket
              return sock.shutdown(socket.SHUT_RDWR)
          except TypeError:
              # SSL.Connection
              return sock.shutdown()
      except socket.error as e:
          # we don't care if the socket is already closed;
          # this will often be the case in an http server context
          if get_errno(e) not in (errno.ENOTCONN, errno.EBADF, errno.ENOTSOCK):
              raise
  