Initial port from Unity Mail

1 files changed, 2618 insertions, 0 deletions

diff --git a/ayatanawebmail/imaplib2.py b/ayatanawebmail/imaplib2.py
new file mode 100755
index 0000000..056acb6
--- /dev/null
+++ b/ayatanawebmail/imaplib2.py
@@ -0,0 +1,2618 @@
+#!/usr/bin/env python
+
+"""Threaded IMAP4 client for Python 3.
+
+Based on RFC 3501 and original imaplib module.
+
+Public classes:   IMAP4
+                  IMAP4_SSL
+                  IMAP4_stream
+
+Public functions: Internaldate2Time
+                  ParseFlags
+                  Time2Internaldate
+"""
+
+
+__all__ = ("IMAP4", "IMAP4_SSL", "IMAP4_stream",
+           "Internaldate2Time", "ParseFlags", "Time2Internaldate",
+           "Mon2num", "MonthNames", "InternalDate")
+
+__version__ = "3.05"
+__release__ = "3"
+__revision__ = "05"
+__credits__ = """
+Authentication code contributed by Donn Cave <donn@u.washington.edu> June 1998.
+String method conversion by ESR, February 2001.
+GET/SETACL contributed by Anthony Baxter <anthony@interlink.com.au> April 2001.
+IMAP4_SSL contributed by Tino Lange <Tino.Lange@isg.de> March 2002.
+GET/SETQUOTA contributed by Andreas Zeidler <az@kreativkombinat.de> June 2002.
+PROXYAUTH contributed by Rick Holbert <holbert.13@osu.edu> November 2002.
+IDLE via threads suggested by Philippe Normand <phil@respyre.org> January 2005.
+GET/SETANNOTATION contributed by Tomas Lindroos <skitta@abo.fi> June 2005.
+COMPRESS/DEFLATE contributed by Bron Gondwana <brong@brong.net> May 2009.
+STARTTLS from Jython's imaplib by Alan Kennedy.
+ID contributed by Dave Baggett <dave@baggett.org> November 2009.
+Improved untagged responses handling suggested by Dave Baggett <dave@baggett.org> November 2009.
+Improved thread naming, and 0 read detection contributed by Grant Edwards <grant.b.edwards@gmail.com> June 2010.
+Improved timeout handling contributed by Ivan Vovnenko <ivovnenko@gmail.com> October 2010.
+Timeout handling further improved by Ethan Glasser-Camp <glasse@cs.rpi.edu> December 2010.
+Time2Internaldate() patch to match RFC2060 specification of English month names from bugs.python.org/issue11024 March 2011.
+starttls() bug fixed with the help of Sebastian Spaeth <sebastian@sspaeth.de> April 2011.
+Threads now set the "daemon" flag (suggested by offlineimap-project) April 2011.
+Single quoting introduced with the help of Vladimir Marek <vladimir.marek@oracle.com> August 2011.
+Support for specifying SSL version by Ryan Kavanagh <rak@debian.org> July 2013.
+Fix for gmail "read 0" error provided by Jim Greenleaf <james.a.greenleaf@gmail.com> August 2013.
+Fix for offlineimap "indexerror: string index out of range" bug provided by Eygene Ryabinkin <rea@codelabs.ru> August 2013.
+Fix for missing idle_lock in _handler() provided by Franklin Brook <franklin@brook.se> August 2014.
+Conversion to Python3 provided by F. Malina <fmalina@gmail.com> February 2015.
+Fix for READ-ONLY error from multiple EXAMINE/SELECT calls by Pierre-Louis Bonicoli <pierre-louis.bonicoli@gmx.fr> March 2015.
+Fix for null strings appended to untagged responses by Pierre-Louis Bonicoli <pierre-louis.bonicoli@gmx.fr> March 2015.
+Fix for correct byte encoding for _CRAM_MD5_AUTH taken from python3.5 imaplib.py June 2015.
+Fix for correct Python 3 exception handling by Tobias Brink <tobias.brink@gmail.com> August 2015.
+Fix to allow interruptible IDLE command by Tim Peoples <dromedary512@users.sf.net> September 2015.
+Add support for TLS levels by Ben Boeckel <mathstuf@gmail.com> September 2015.
+Fix for shutown exception by Sebastien Gross <seb@chezwam.org> November 2015."""
+__author__ = "Piers Lauder <piers@janeelix.com>"
+__URL__ = "http://imaplib2.sourceforge.net"
+__license__ = "Python License"
+
+import binascii, calendar, errno, os, queue, random, re, select, socket, sys, time, threading, zlib
+
+
+select_module = select
+
+#       Globals
+
+CRLF = b'\r\n'
+IMAP4_PORT = 143
+IMAP4_SSL_PORT = 993
+
+IDLE_TIMEOUT_RESPONSE = b'* IDLE TIMEOUT\r\n'
+IDLE_TIMEOUT = 60*29                            # Don't stay in IDLE state longer
+READ_POLL_TIMEOUT = 30                          # Without this timeout interrupted network connections can hang reader
+READ_SIZE = 32768                               # Consume all available in socket
+
+DFLT_DEBUG_BUF_LVL = 3                          # Level above which the logging output goes directly to stderr
+
+TLS_SECURE = "tls_secure"                       # Recognised TLS levels
+TLS_NO_SSL = "tls_no_ssl"
+TLS_COMPAT = "tls_compat"
+
+AllowedVersions = ('IMAP4REV1', 'IMAP4')        # Most recent first
+
+#       Commands
+
+CMD_VAL_STATES = 0
+CMD_VAL_ASYNC = 1
+NONAUTH, AUTH, SELECTED, LOGOUT = 'NONAUTH', 'AUTH', 'SELECTED', 'LOGOUT'
+
+Commands = {
+        # name            valid states             asynchronous
+        'APPEND':       ((AUTH, SELECTED),            False),
+        'AUTHENTICATE': ((NONAUTH,),                  False),
+        'CAPABILITY':   ((NONAUTH, AUTH, SELECTED),   True),
+        'CHECK':        ((SELECTED,),                 True),
+        'CLOSE':        ((SELECTED,),                 False),
+        'COMPRESS':     ((AUTH,),                     False),
+        'COPY':         ((SELECTED,),                 True),
+        'CREATE':       ((AUTH, SELECTED),            True),
+        'DELETE':       ((AUTH, SELECTED),            True),
+        'DELETEACL':    ((AUTH, SELECTED),            True),
+        'ENABLE':       ((AUTH,),                     False),
+        'EXAMINE':      ((AUTH, SELECTED),            False),
+        'EXPUNGE':      ((SELECTED,),                 True),
+        'FETCH':        ((SELECTED,),                 True),
+        'GETACL':       ((AUTH, SELECTED),            True),
+        'GETANNOTATION':((AUTH, SELECTED),            True),
+        'GETQUOTA':     ((AUTH, SELECTED),            True),
+        'GETQUOTAROOT': ((AUTH, SELECTED),            True),
+        'ID':           ((NONAUTH, AUTH, LOGOUT, SELECTED),   True),
+        'IDLE':         ((SELECTED,),                 False),
+        'LIST':         ((AUTH, SELECTED),            True),
+        'LOGIN':        ((NONAUTH,),                  False),
+        'LOGOUT':       ((NONAUTH, AUTH, LOGOUT, SELECTED),   False),
+        'LSUB':         ((AUTH, SELECTED),            True),
+        'MYRIGHTS':     ((AUTH, SELECTED),            True),
+        'NAMESPACE':    ((AUTH, SELECTED),            True),
+        'NOOP':         ((NONAUTH, AUTH, SELECTED),   True),
+        'PARTIAL':      ((SELECTED,),                 True),
+        'PROXYAUTH':    ((AUTH,),                     False),
+        'RENAME':       ((AUTH, SELECTED),            True),
+        'SEARCH':       ((SELECTED,),                 True),
+        'SELECT':       ((AUTH, SELECTED),            False),
+        'SETACL':       ((AUTH, SELECTED),            False),
+        'SETANNOTATION':((AUTH, SELECTED),            True),
+        'SETQUOTA':     ((AUTH, SELECTED),            False),
+        'SORT':         ((SELECTED,),                 True),
+        'STARTTLS':     ((NONAUTH,),                  False),
+        'STATUS':       ((AUTH, SELECTED),            True),
+        'STORE':        ((SELECTED,),                 True),
+        'SUBSCRIBE':    ((AUTH, SELECTED),            False),
+        'THREAD':       ((SELECTED,),                 True),
+        'UID':          ((SELECTED,),                 True),
+        'UNSUBSCRIBE':  ((AUTH, SELECTED),            False),
+        }
+
+UID_direct = ('SEARCH', 'SORT', 'THREAD')
+
+
+def Int2AP(num):
+
+    """string = Int2AP(num)
+    Return 'num' converted to bytes using characters from the set 'A'..'P'
+    """
+
+    val = b''; AP = b'ABCDEFGHIJKLMNOP'
+    num = int(abs(num))
+    while num:
+        num, mod = divmod(num, 16)
+        val = AP[mod:mod+1] + val
+    return val
+
+
+
+class Request(object):
+
+    """Private class to represent a request awaiting response."""
+
+    def __init__(self, parent, name=None, callback=None, cb_arg=None, cb_self=False):
+        self.parent = parent
+        self.name = name
+        self.callback = callback               # Function called to process result
+        if not cb_self:
+            self.callback_arg = cb_arg         # Optional arg passed to "callback"
+        else:
+            self.callback_arg = (self, cb_arg) # Self reference required in callback arg
+
+        self.tag = parent.tagpre + bytes(str(parent.tagnum), 'ASCII')
+        parent.tagnum += 1
+
+        self.ready = threading.Event()
+        self.response = None
+        self.aborted = None
+        self.data = None
+
+
+    def abort(self, typ, val):
+        self.aborted = (typ, val)
+        self.deliver(None)
+
+
+    def get_response(self, exc_fmt=None):
+        self.callback = None
+        if __debug__: self.parent._log(3, '%s:%s.ready.wait' % (self.name, self.tag))
+        self.ready.wait()
+
+        if self.aborted is not None:
+            typ, val = self.aborted
+            if exc_fmt is None:
+                exc_fmt = '%s - %%s' % typ
+            raise typ(exc_fmt % str(val))
+
+        return self.response
+
+
+    def deliver(self, response):
+        if self.callback is not None:
+            self.callback((response, self.callback_arg, self.aborted))
+            return
+
+        self.response = response
+        self.ready.set()
+        if __debug__: self.parent._log(3, '%s:%s.ready.set' % (self.name, self.tag))
+
+
+
+
+class IMAP4(object):
+
+    """Threaded IMAP4 client class.
+
+    Instantiate with:
+        IMAP4(host=None, port=None, debug=None, debug_file=None, identifier=None, timeout=None, debug_buf_lvl=None)
+
+        host          - host's name (default: localhost);
+        port          - port number (default: standard IMAP4 port);
+        debug         - debug level (default: 0 - no debug);
+        debug_file    - debug stream (default: sys.stderr);
+        identifier    - thread identifier prefix (default: host);
+        timeout       - timeout in seconds when expecting a command response (default: no timeout),
+        debug_buf_lvl - debug level at which buffering is turned off.
+
+    All IMAP4rev1 commands are supported by methods of the same name.
+
+    Each command returns a tuple: (type, [data, ...]) where 'type'
+    is usually 'OK' or 'NO', and 'data' is either the text from the
+    tagged response, or untagged results from command. Each 'data' is
+    either a string, or a tuple. If a tuple, then the first part is the
+    header of the response, and the second part contains the data (ie:
+    'literal' value).
+
+    Errors raise the exception class <instance>.error("<reason>").
+    IMAP4 server errors raise <instance>.abort("<reason>"), which is
+    a sub-class of 'error'. Mailbox status changes from READ-WRITE to
+    READ-ONLY raise the exception class <instance>.readonly("<reason>"),
+    which is a sub-class of 'abort'.
+
+    "error" exceptions imply a program error.
+    "abort" exceptions imply the connection should be reset, and
+            the command re-tried.
+    "readonly" exceptions imply the command should be re-tried.
+
+    All commands take two optional named arguments:
+        'callback' and 'cb_arg'
+    If 'callback' is provided then the command is asynchronous, so after
+    the command is queued for transmission, the call returns immediately
+    with the tuple (None, None).
+    The result will be posted by invoking "callback" with one arg, a tuple:
+        callback((result, cb_arg, None))
+    or, if there was a problem:
+        callback((None, cb_arg, (exception class, reason)))
+
+    Otherwise the command is synchronous (waits for result). But note
+    that state-changing commands will both block until previous commands
+    have completed, and block subsequent commands until they have finished.
+
+    All (non-callback) string arguments to commands are converted to bytes,
+    except for AUTHENTICATE, and the last argument to APPEND which is
+    passed as an IMAP4 literal.  NB: the 'password' argument to the LOGIN
+    command is always quoted.
+
+    There is one instance variable, 'state', that is useful for tracking
+    whether the client needs to login to the server. If it has the
+    value "AUTH" after instantiating the class, then the connection
+    is pre-authenticated (otherwise it will be "NONAUTH"). Selecting a
+    mailbox changes the state to be "SELECTED", closing a mailbox changes
+    back to "AUTH", and once the client has logged out, the state changes
+    to "LOGOUT" and no further commands may be issued.
+
+    Note: to use this module, you must read the RFCs pertaining to the
+    IMAP4 protocol, as the semantics of the arguments to each IMAP4
+    command are left to the invoker, not to mention the results. Also,
+    most IMAP servers implement a sub-set of the commands available here.
+
+    Note also that you must call logout() to shut down threads before
+    discarding an instance.
+    """
+
+    class error(Exception): pass    # Logical errors - debug required
+    class abort(error): pass        # Service errors - close and retry
+    class readonly(abort): pass     # Mailbox status changed to READ-ONLY
+
+    # These must be encoded according to utf8 setting in _mode_xxx():
+    _literal = br'.*{(?P<size>\d+)}$'
+    _untagged_status = br'\* (?P<data>\d+) (?P<type>[A-Z-]+)( (?P<data2>.*))?'
+
+    continuation_cre = re.compile(br'\+( (?P<data>.*))?')
+    mapCRLF_cre = re.compile(br'\r\n|\r|\n')
+    response_code_cre = re.compile(br'\[(?P<type>[A-Z-]+)( (?P<data>[^\]]*))?\]')
+    untagged_response_cre = re.compile(br'\* (?P<type>[A-Z-]+)( (?P<data>.*))?')
+
+
+    def __init__(self, host=None, port=None, debug=None, debug_file=None, identifier=None, timeout=None, debug_buf_lvl=None):
+
+        self.state = NONAUTH            # IMAP4 protocol state
+        self.literal = None             # A literal argument to a command
+        self.tagged_commands = {}       # Tagged commands awaiting response
+        self.untagged_responses = []    # [[typ: [data, ...]], ...]
+        self.mailbox = None             # Current mailbox selected
+        self.is_readonly = False        # READ-ONLY desired state
+        self.idle_rqb = None            # Server IDLE Request - see _IdleCont
+        self.idle_timeout = None        # Must prod server occasionally
+
+        self._expecting_data = False    # Expecting message data
+        self._expecting_data_len = 0    # How many characters we expect
+        self._accumulated_data = []     # Message data accumulated so far
+        self._literal_expected = None   # Message data descriptor
+
+        self.compressor = None          # COMPRESS/DEFLATE if not None
+        self.decompressor = None
+        self._tls_established = False
+
+        # Create unique tag for this session,
+        # and compile tagged response matcher.
+
+        self.tagnum = 0
+        self.tagpre = Int2AP(random.randint(4096, 65535))
+        self.tagre = re.compile(br'(?P<tag>'
+                        + self.tagpre
+                        + br'\d+) (?P<type>[A-Z]+) (?P<data>.*)', re.ASCII)
+
+        self._mode_ascii()
+
+        if __debug__: self._init_debug(debug, debug_file, debug_buf_lvl)
+
+        self.resp_timeout = timeout     # Timeout waiting for command response
+
+        if timeout is not None and timeout < READ_POLL_TIMEOUT:
+            self.read_poll_timeout = timeout
+        else:
+            self.read_poll_timeout = READ_POLL_TIMEOUT
+        self.read_size = READ_SIZE
+
+        # Open socket to server.
+
+        self.open(host, port)
+
+        if __debug__:
+            if debug:
+                self._mesg('connected to %s on port %s' % (self.host, self.port))
+
+        # Threading
+
+        if identifier is not None:
+            self.identifier = identifier
+        else:
+            self.identifier = self.host
+        if self.identifier:
+            self.identifier += ' '
+
+        self.Terminate = self.TerminateReader = False
+
+        self.state_change_free = threading.Event()
+        self.state_change_pending = threading.Lock()
+        self.commands_lock = threading.Lock()
+        self.idle_lock = threading.Lock()
+
+        self.ouq = queue.Queue(10)
+        self.inq = queue.Queue()
+
+        self.wrth = threading.Thread(target=self._writer)
+        self.wrth.setDaemon(True)
+        self.wrth.start()
+        self.rdth = threading.Thread(target=self._reader)
+        self.rdth.setDaemon(True)
+        self.rdth.start()
+        self.inth = threading.Thread(target=self._handler)
+        self.inth.setDaemon(True)
+        self.inth.start()
+
+        # Get server welcome message,
+        # request and store CAPABILITY response.
+
+        try:
+            self.welcome = self._request_push(name='welcome', tag='continuation').get_response('IMAP4 protocol error: %s')[1]
+
+            if self._get_untagged_response('PREAUTH'):
+                self.state = AUTH
+                if __debug__: self._log(1, 'state => AUTH')
+            elif self._get_untagged_response('OK'):
+                if __debug__: self._log(1, 'state => NONAUTH')
+            else:
+                raise self.error('unrecognised server welcome message: %s' % repr(self.welcome))
+
+            self._get_capabilities()
+            if __debug__: self._log(1, 'CAPABILITY: %r' % (self.capabilities,))
+
+            for version in AllowedVersions:
+                if not version in self.capabilities:
+                    continue
+                self.PROTOCOL_VERSION = version
+                break
+            else:
+                raise self.error('server not IMAP4 compliant')
+        except:
+            self._close_threads()
+            raise
+
+
+    def __getattr__(self, attr):
+        # Allow UPPERCASE variants of IMAP4 command methods.
+        if attr in Commands:
+            return getattr(self, attr.lower())
+        raise AttributeError("Unknown IMAP4 command: '%s'" % attr)
+
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, *args):
+        try:
+            self.logout()
+        except OSError:
+            pass
+
+
+    def _mode_ascii(self):
+        self.utf8_enabled = False
+        self._encoding = 'ascii'
+        self.literal_cre = re.compile(self._literal, re.ASCII)
+        self.untagged_status_cre = re.compile(self._untagged_status, re.ASCII)
+
+
+    def _mode_utf8(self):
+        self.utf8_enabled = True
+        self._encoding = 'utf-8'
+        self.literal_cre = re.compile(self._literal)
+        self.untagged_status_cre = re.compile(self._untagged_status)
+
+
+
+    #       Overridable methods
+
+
+    def open(self, host=None, port=None):
+        """open(host=None, port=None)
+        Setup connection to remote server on "host:port"
+            (default: localhost:standard IMAP4 port).
+        This connection will be used by the routines:
+            read, send, shutdown, socket."""
+
+        self.host = self._choose_nonull_or_dflt('', host)
+        self.port = self._choose_nonull_or_dflt(IMAP4_PORT, port)
+        self.sock = self.open_socket()
+        self.read_fd = self.sock.fileno()
+
+
+    def open_socket(self):
+        """open_socket()
+        Open socket choosing first address family available."""
+
+        return socket.create_connection((self.host, self.port))
+
+
+    def ssl_wrap_socket(self):
+
+        try:
+            import ssl
+
+            TLS_MAP = {}
+            if hasattr(ssl, "PROTOCOL_TLSv1_2"):
+                TLS_MAP[TLS_SECURE] = {
+                    "tls1_2": ssl.PROTOCOL_TLSv1_2,
+                    "tls1_1": ssl.PROTOCOL_TLSv1_1,
+                }
+            else:
+                TLS_MAP[TLS_SECURE] = {}
+            TLS_MAP[TLS_NO_SSL] = TLS_MAP[TLS_SECURE].copy()
+            TLS_MAP[TLS_NO_SSL].update({
+                "tls1": ssl.PROTOCOL_TLSv1,
+            })
+            TLS_MAP[TLS_COMPAT] = TLS_MAP[TLS_NO_SSL].copy()
+            TLS_MAP[TLS_COMPAT].update({
+                "ssl23": ssl.PROTOCOL_SSLv23,
+                None: ssl.PROTOCOL_SSLv23,
+            })
+            if hasattr(ssl, "PROTOCOL_SSLv3"):          # Might not be available.
+                TLS_MAP[TLS_COMPAT].update({
+                    "ssl3": ssl.PROTOCOL_SSLv3
+                })
+
+            if self.ca_certs is not None:
+                cert_reqs = ssl.CERT_REQUIRED
+            else:
+                cert_reqs = ssl.CERT_NONE
+
+            if self.tls_level not in TLS_MAP:
+                raise RuntimeError("unknown tls_level: %s" % self.tls_level)
+
+            if self.ssl_version not in TLS_MAP[self.tls_level]:
+                raise socket.sslerror("Invalid SSL version '%s' requested for tls_version '%s'" % (self.ssl_version, self.tls_level))
+
+            ssl_version =  TLS_MAP[self.tls_level][self.ssl_version]
+
+            self.sock = ssl.wrap_socket(self.sock, self.keyfile, self.certfile, ca_certs=self.ca_certs, cert_reqs=cert_reqs, ssl_version=ssl_version)
+            ssl_exc = ssl.SSLError
+            self.read_fd = self.sock.fileno()
+        except ImportError:
+            # No ssl module, and socket.ssl has no fileno(), and does not allow certificate verification
+            raise socket.sslerror("imaplib SSL mode does not work without ssl module")
+
+        if self.cert_verify_cb is not None:
+            cert_err = self.cert_verify_cb(self.sock.getpeercert(), self.host)
+            if cert_err:
+                raise ssl_exc(cert_err)
+
+        # Allow sending of keep-alive messages - seems to prevent some servers
+        # from closing SSL, leading to deadlocks.
+        self.sock.setsockopt(socket.SOL_SOCKET, socket.SO_KEEPALIVE, 1)
+
+
+
+    def start_compressing(self):
+        """start_compressing()
+        Enable deflate compression on the socket (RFC 4978)."""
+
+        # rfc 1951 - pure DEFLATE, so use -15 for both windows
+        self.decompressor = zlib.decompressobj(-15)
+        self.compressor = zlib.compressobj(zlib.Z_DEFAULT_COMPRESSION, zlib.DEFLATED, -15)
+
+
+    def read(self, size):
+        """data = read(size)
+        Read at most 'size' bytes from remote."""
+
+        if self.decompressor is None:
+            return self.sock.recv(size)
+
+        if self.decompressor.unconsumed_tail:
+            data = self.decompressor.unconsumed_tail
+        else:
+            data = self.sock.recv(READ_SIZE)
+
+        return self.decompressor.decompress(data, size)
+
+
+    def send(self, data):
+        """send(data)
+        Send 'data' to remote."""
+
+        if self.compressor is not None:
+            data = self.compressor.compress(data)
+            data += self.compressor.flush(zlib.Z_SYNC_FLUSH)
+
+        self.sock.sendall(data)
+
+
+    def shutdown(self):
+        """shutdown()
+        Close I/O established in "open"."""
+
+        try:
+            self.sock.shutdown(socket.SHUT_RDWR)
+        except Exception as e:
+            # The server might already have closed the connection
+            if e.errno != errno.ENOTCONN:
+                raise
+        finally:
+            self.sock.close()
+
+
+    def socket(self):
+        """socket = socket()
+        Return socket instance used to connect to IMAP4 server."""
+
+        return self.sock
+
+
+
+    #       Utility methods
+
+
+    def enable_compression(self):
+        """enable_compression()
+        Ask the server to start compressing the connection.
+        Should be called from user of this class after instantiation, as in:
+            if 'COMPRESS=DEFLATE' in imapobj.capabilities:
+                imapobj.enable_compression()"""
+
+        try:
+            typ, dat = self._simple_command('COMPRESS', 'DEFLATE')
+            if typ == 'OK':
+                self.start_compressing()
+                if __debug__: self._log(1, 'Enabled COMPRESS=DEFLATE')
+        finally:
+            self._release_state_change()
+
+
+    def pop_untagged_responses(self):
+        """ for typ,data in pop_untagged_responses(): pass
+        Generator for any remaining untagged responses.
+        Returns and removes untagged responses in order of reception.
+        Use at your own risk!"""
+
+        while self.untagged_responses:
+            self.commands_lock.acquire()
+            try:
+                yield self.untagged_responses.pop(0)
+            finally:
+                self.commands_lock.release()
+
+
+    def recent(self, **kw):
+        """(typ, [data]) = recent()
+        Return 'RECENT' responses if any exist,
+        else prompt server for an update using the 'NOOP' command.
+        'data' is None if no new messages,
+        else list of RECENT responses, most recent last."""
+
+        name = 'RECENT'
+        typ, dat = self._untagged_response(None, [None], name)
+        if dat != [None]:
+            return self._deliver_dat(typ, dat, kw)
+        kw['untagged_response'] = name
+        return self.noop(**kw)  # Prod server for response
+
+
+    def response(self, code, **kw):
+        """(code, [data]) = response(code)
+        Return data for response 'code' if received, or None.
+        Old value for response 'code' is cleared."""
+
+        typ, dat = self._untagged_response(code, [None], code.upper())
+        return self._deliver_dat(typ, dat, kw)
+
+
+
+
+    #       IMAP4 commands
+
+
+    def append(self, mailbox, flags, date_time, message, **kw):
+        """(typ, [data]) = append(mailbox, flags, date_time, message)
+        Append message to named mailbox.
+        All args except `message' can be None."""
+
+        name = 'APPEND'
+        if not mailbox:
+            mailbox = 'INBOX'
+        if flags:
+            if (flags[0],flags[-1]) != ('(',')'):
+                flags = '(%s)' % flags
+        else:
+            flags = None
+        if date_time:
+            date_time = Time2Internaldate(date_time)
+        else:
+            date_time = None
+        if isinstance(message, str):
+            message = bytes(message, 'ASCII')
+        literal = self.mapCRLF_cre.sub(CRLF, message)
+        if self.utf8_enabled:
+            literal = b'UTF8 (' + literal + b')'
+        self.literal = literal
+        try:
+            return self._simple_command(name, mailbox, flags, date_time, **kw)
+        finally:
+            self._release_state_change()
+
+
+    def authenticate(self, mechanism, authobject, **kw):
+        """(typ, [data]) = authenticate(mechanism, authobject)
+        Authenticate command - requires response processing.
+
+        'mechanism' specifies which authentication mechanism is to
+        be used - it must appear in <instance>.capabilities in the
+        form AUTH=<mechanism>.
+
+        'authobject' must be a callable object:
+
+                data = authobject(response)
+
+        It will be called to process server continuation responses,
+        the 'response' argument will be a 'bytes'.  It should return
+        bytes that will be encoded and sent to server.  It should
+        return None if the client abort response '*' should be sent
+        instead."""
+
+        self.literal = _Authenticator(authobject).process
+        try:
+            typ, dat = self._simple_command('AUTHENTICATE', mechanism.upper())
+            if typ != 'OK':
+                self._deliver_exc(self.error, dat[-1], kw)
+            self.state = AUTH
+            if __debug__: self._log(1, 'state => AUTH')
+        finally:
+            self._release_state_change()
+        return self._deliver_dat(typ, dat, kw)
+
+
+    def capability(self, **kw):
+        """(typ, [data]) = capability()
+        Fetch capabilities list from server."""
+
+        name = 'CAPABILITY'
+        kw['untagged_response'] = name
+        return self._simple_command(name, **kw)
+
+
+    def check(self, **kw):
+        """(typ, [data]) = check()
+        Checkpoint mailbox on server."""
+
+        return self._simple_command('CHECK', **kw)
+
+
+    def close(self, **kw):
+        """(typ, [data]) = close()
+        Close currently selected mailbox.
+
+        Deleted messages are removed from writable mailbox.
+        This is the recommended command before 'LOGOUT'."""
+
+        if self.state != 'SELECTED':
+            raise self.error('No mailbox selected.')
+        try:
+            typ, dat = self._simple_command('CLOSE')
+        finally:
+            self.state = AUTH
+            if __debug__: self._log(1, 'state => AUTH')
+            self._release_state_change()
+        return self._deliver_dat(typ, dat, kw)
+
+
+    def copy(self, message_set, new_mailbox, **kw):
+        """(typ, [data]) = copy(message_set, new_mailbox)
+        Copy 'message_set' messages onto end of 'new_mailbox'."""
+
+        return self._simple_command('COPY', message_set, new_mailbox, **kw)
+
+
+    def create(self, mailbox, **kw):
+        """(typ, [data]) = create(mailbox)
+        Create new mailbox."""
+
+        return self._simple_command('CREATE', mailbox, **kw)
+
+
+    def delete(self, mailbox, **kw):
+        """(typ, [data]) = delete(mailbox)
+        Delete old mailbox."""
+
+        return self._simple_command('DELETE', mailbox, **kw)
+
+
+    def deleteacl(self, mailbox, who, **kw):
+        """(typ, [data]) = deleteacl(mailbox, who)
+        Delete the ACLs (remove any rights) set for who on mailbox."""
+
+        return self._simple_command('DELETEACL', mailbox, who, **kw)
+
+
+    def enable(self, capability):
+        """Send an RFC5161 enable string to the server.
+
+        (typ, [data]) = <intance>.enable(capability)
+        """
+        if 'ENABLE' not in self.capabilities:
+            raise self.error("Server does not support ENABLE")
+        typ, data = self._simple_command('ENABLE', capability)
+        if typ == 'OK' and 'UTF8=ACCEPT' in capability.upper():
+            self._mode_utf8()
+        return typ, data
+
+
+    def examine(self, mailbox='INBOX', **kw):
+        """(typ, [data]) = examine(mailbox='INBOX')
+        Select a mailbox for READ-ONLY access. (Flushes all untagged responses.)
+        'data' is count of messages in mailbox ('EXISTS' response).
+        Mandated responses are ('FLAGS', 'EXISTS', 'RECENT', 'UIDVALIDITY'), so
+        other responses should be obtained via "response('FLAGS')" etc."""
+
+        return self.select(mailbox=mailbox, readonly=True, **kw)
+
+
+    def expunge(self, **kw):
+        """(typ, [data]) = expunge()
+        Permanently remove deleted items from selected mailbox.
+        Generates 'EXPUNGE' response for each deleted message.
+        'data' is list of 'EXPUNGE'd message numbers in order received."""
+
+        name = 'EXPUNGE'
+        kw['untagged_response'] = name
+        return self._simple_command(name, **kw)
+
+
+    def fetch(self, message_set, message_parts, **kw):
+        """(typ, [data, ...]) = fetch(message_set, message_parts)
+        Fetch (parts of) messages.
+        'message_parts' should be a string of selected parts
+        enclosed in parentheses, eg: "(UID BODY[TEXT])".
+        'data' are tuples of message part envelope and data,
+        followed by a string containing the trailer."""
+
+        name = 'FETCH'
+        kw['untagged_response'] = name
+        return self._simple_command(name, message_set, message_parts, **kw)
+
+
+    def getacl(self, mailbox, **kw):
+        """(typ, [data]) = getacl(mailbox)
+        Get the ACLs for a mailbox."""
+
+        kw['untagged_response'] = 'ACL'
+        return self._simple_command('GETACL', mailbox, **kw)
+
+
+    def getannotation(self, mailbox, entry, attribute, **kw):
+        """(typ, [data]) = getannotation(mailbox, entry, attribute)
+        Retrieve ANNOTATIONs."""
+
+        kw['untagged_response'] = 'ANNOTATION'
+        return self._simple_command('GETANNOTATION', mailbox, entry, attribute, **kw)
+
+
+    def getquota(self, root, **kw):
+        """(typ, [data]) = getquota(root)
+        Get the quota root's resource usage and limits.
+        (Part of the IMAP4 QUOTA extension defined in rfc2087.)"""
+
+        kw['untagged_response'] = 'QUOTA'
+        return self._simple_command('GETQUOTA', root, **kw)
+
+
+    def getquotaroot(self, mailbox, **kw):
+        # Hmmm, this is non-std! Left for backwards-compatibility, sigh.
+        # NB: usage should have been defined as:
+        #   (typ, [QUOTAROOT responses...]) = getquotaroot(mailbox)
+        #   (typ, [QUOTA responses...]) = response('QUOTA')
+        """(typ, [[QUOTAROOT responses...], [QUOTA responses...]]) = getquotaroot(mailbox)
+        Get the list of quota roots for the named mailbox."""
+
+        typ, dat = self._simple_command('GETQUOTAROOT', mailbox)
+        typ, quota = self._untagged_response(typ, dat, 'QUOTA')
+        typ, quotaroot = self._untagged_response(typ, dat, 'QUOTAROOT')
+        return self._deliver_dat(typ, [quotaroot, quota], kw)
+
+
+    def id(self, *kv_pairs, **kw):
+        """(typ, [data]) = <instance>.id(kv_pairs)
+        'kv_pairs' is a possibly empty list of keys and values.
+        'data' is a list of ID key value pairs or NIL.
+        NB: a single argument is assumed to be correctly formatted and is passed through unchanged
+        (for backward compatibility with earlier version).
+        Exchange information for problem analysis and determination.
+        The ID extension is defined in RFC 2971. """
+
+        name = 'ID'
+        kw['untagged_response'] = name
+
+        if not kv_pairs:
+            data = 'NIL'
+        elif len(kv_pairs) == 1:
+            data = kv_pairs[0]     # Assume invoker passing correctly formatted string (back-compat)
+        else:
+            data = '(%s)' % ' '.join([(arg and self._quote(arg) or 'NIL') for arg in kv_pairs])
+
+        return self._simple_command(name, data, **kw)
+
+
+    def idle(self, timeout=None, **kw):
+        """"(typ, [data]) = idle(timeout=None)
+        Put server into IDLE mode until server notifies some change,
+        or 'timeout' (secs) occurs (default: 29 minutes),
+        or another IMAP4 command is scheduled."""
+
+        name = 'IDLE'
+        self.literal = _IdleCont(self, timeout).process
+        try:
+            return self._simple_command(name, **kw)
+        finally:
+            self._release_state_change()
+
+
+    def list(self, directory='""', pattern='*', **kw):
+        """(typ, [data]) = list(directory='""', pattern='*')
+        List mailbox names in directory matching pattern.
+        'data' is list of LIST responses.
+
+        NB: for 'pattern':
+        % matches all except separator ( so LIST "" "%" returns names at root)
+        * matches all (so LIST "" "*" returns whole directory tree from root)"""
+
+        name = 'LIST'
+        kw['untagged_response'] = name
+        return self._simple_command(name, directory, pattern, **kw)
+
+
+    def login(self, user, password, **kw):
+        """(typ, [data]) = login(user, password)
+        Identify client using plaintext password.
+        NB: 'password' will be quoted."""
+
+        try:
+            typ, dat = self._simple_command('LOGIN', user, self._quote(password))
+            if typ != 'OK':
+                self._deliver_exc(self.error, dat[-1], kw)
+            self.state = AUTH
+            if __debug__: self._log(1, 'state => AUTH')
+        finally:
+            self._release_state_change()
+        return self._deliver_dat(typ, dat, kw)
+
+
+    def login_cram_md5(self, user, password, **kw):
+        """(typ, [data]) = login_cram_md5(user, password)
+        Force use of CRAM-MD5 authentication."""
+
+        self.user, self.password = user, password
+        return self.authenticate('CRAM-MD5', self._CRAM_MD5_AUTH, **kw)
+
+
+    def _CRAM_MD5_AUTH(self, challenge):
+        """Authobject to use with CRAM-MD5 authentication."""
+        import hmac
+        pwd = (self.password.encode('utf-8') if isinstance(self.password, str)
+                                             else self.password)
+        return self.user + " " + hmac.HMAC(pwd, challenge, 'md5').hexdigest()
+
+
+    def logout(self, **kw):
+        """(typ, [data]) = logout()
+        Shutdown connection to server.
+        Returns server 'BYE' response.
+        NB: You must call this to shut down threads before discarding an instance."""
+
+        self.state = LOGOUT
+        if __debug__: self._log(1, 'state => LOGOUT')
+
+        try:
+            try:
+                typ, dat = self._simple_command('LOGOUT')
+            except:
+                typ, dat = 'NO', ['%s: %s' % sys.exc_info()[:2]]
+                if __debug__: self._log(1, dat)
+
+            self._close_threads()
+        finally:
+            self._release_state_change()
+
+        if __debug__: self._log(1, 'connection closed')
+
+        bye = self._get_untagged_response('BYE', leave=True)
+        if bye:
+            typ, dat = 'BYE', bye
+        return self._deliver_dat(typ, dat, kw)
+
+
+    def lsub(self, directory='""', pattern='*', **kw):
+        """(typ, [data, ...]) = lsub(directory='""', pattern='*')
+        List 'subscribed' mailbox names in directory matching pattern.
+        'data' are tuples of message part envelope and data."""
+
+        name = 'LSUB'
+        kw['untagged_response'] = name
+        return self._simple_command(name, directory, pattern, **kw)
+
+
+    def myrights(self, mailbox, **kw):
+        """(typ, [data]) = myrights(mailbox)
+        Show my ACLs for a mailbox (i.e. the rights that I have on mailbox)."""
+
+        name = 'MYRIGHTS'
+        kw['untagged_response'] = name
+        return self._simple_command(name, mailbox, **kw)
+
+
+    def namespace(self, **kw):
+        """(typ, [data, ...]) = namespace()
+        Returns IMAP namespaces ala rfc2342."""
+
+        name = 'NAMESPACE'
+        kw['untagged_response'] = name
+        return self._simple_command(name, **kw)
+
+
+    def noop(self, **kw):
+        """(typ, [data]) = noop()
+        Send NOOP command."""
+
+        if __debug__: self._dump_ur(3)
+        return self._simple_command('NOOP', **kw)
+
+
+    def partial(self, message_num, message_part, start, length, **kw):
+        """(typ, [data, ...]) = partial(message_num, message_part, start, length)
+        Fetch truncated part of a message.
+        'data' is tuple of message part envelope and data.
+        NB: obsolete."""
+
+        name = 'PARTIAL'
+        kw['untagged_response'] = 'FETCH'
+        return self._simple_command(name, message_num, message_part, start, length, **kw)
+
+
+    def proxyauth(self, user, **kw):
+        """(typ, [data]) = proxyauth(user)
+        Assume authentication as 'user'.
+        (Allows an authorised administrator to proxy into any user's mailbox.)"""
+
+        try:
+            return self._simple_command('PROXYAUTH', user, **kw)
+        finally:
+            self._release_state_change()
+
+
+    def rename(self, oldmailbox, newmailbox, **kw):
+        """(typ, [data]) = rename(oldmailbox, newmailbox)
+        Rename old mailbox name to new."""
+
+        return self._simple_command('RENAME', oldmailbox, newmailbox, **kw)
+
+
+    def search(self, charset, *criteria, **kw):
+        """(typ, [data]) = search(charset, criterion, ...)
+        Search mailbox for matching messages.
+        If UTF8 is enabled, charset MUST be None.
+        'data' is space separated list of matching message numbers."""
+
+        name = 'SEARCH'
+        kw['untagged_response'] = name
+        if charset:
+            if self.utf8_enabled:
+                raise self.error("Non-None charset not valid in UTF8 mode")
+            return self._simple_command(name, 'CHARSET', charset, *criteria, **kw)
+        return self._simple_command(name, *criteria, **kw)
+
+
+    def select(self, mailbox='INBOX', readonly=False, **kw):
+        """(typ, [data]) = select(mailbox='INBOX', readonly=False)
+        Select a mailbox. (Flushes all untagged responses.)
+        'data' is count of messages in mailbox ('EXISTS' response).
+        Mandated responses are ('FLAGS', 'EXISTS', 'RECENT', 'UIDVALIDITY'), so
+        other responses should be obtained via "response('FLAGS')" etc."""
+
+        self.mailbox = mailbox
+
+        self.is_readonly = bool(readonly)
+        if readonly:
+            name = 'EXAMINE'
+        else:
+            name = 'SELECT'
+        try:
+            rqb = self._command(name, mailbox)
+            typ, dat = rqb.get_response('command: %s => %%s' % rqb.name)
+            if typ != 'OK':
+                if self.state == SELECTED:
+                    self.state = AUTH
+                if __debug__: self._log(1, 'state => AUTH')
+                if typ == 'BAD':
+                    self._deliver_exc(self.error, '%s command error: %s %s. Data: %.100s' % (name, typ, dat, mailbox), kw)
+                return self._deliver_dat(typ, dat, kw)
+            self.state = SELECTED
+            if __debug__: self._log(1, 'state => SELECTED')
+        finally:
+            self._release_state_change()
+
+        if self._get_untagged_response('READ-ONLY', leave=True) and not readonly:
+            if __debug__: self._dump_ur(1)
+            self._deliver_exc(self.readonly, '%s is not writable' % mailbox, kw)
+        typ, dat = self._untagged_response(typ, [None], 'EXISTS')
+        return self._deliver_dat(typ, dat, kw)
+
+
+    def setacl(self, mailbox, who, what, **kw):
+        """(typ, [data]) = setacl(mailbox, who, what)
+        Set a mailbox acl."""
+
+        try:
+            return self._simple_command('SETACL', mailbox, who, what, **kw)
+        finally:
+            self._release_state_change()
+
+
+    def setannotation(self, *args, **kw):
+        """(typ, [data]) = setannotation(mailbox[, entry, attribute]+)
+        Set ANNOTATIONs."""
+
+        kw['untagged_response'] = 'ANNOTATION'
+        return self._simple_command('SETANNOTATION', *args, **kw)
+
+
+    def setquota(self, root, limits, **kw):
+        """(typ, [data]) = setquota(root, limits)
+        Set the quota root's resource limits."""
+
+        kw['untagged_response'] = 'QUOTA'
+        try:
+            return self._simple_command('SETQUOTA', root, limits, **kw)
+        finally:
+            self._release_state_change()
+
+
+    def sort(self, sort_criteria, charset, *search_criteria, **kw):
+        """(typ, [data]) = sort(sort_criteria, charset, search_criteria, ...)
+        IMAP4rev1 extension SORT command."""
+
+        name = 'SORT'
+        if (sort_criteria[0],sort_criteria[-1]) != ('(',')'):
+            sort_criteria = '(%s)' % sort_criteria
+        kw['untagged_response'] = name
+        return self._simple_command(name, sort_criteria, charset, *search_criteria, **kw)
+
+
+    def starttls(self, keyfile=None, certfile=None, ca_certs=None, cert_verify_cb=None, ssl_version="ssl23", tls_level=TLS_COMPAT, **kw):
+        """(typ, [data]) = starttls(keyfile=None, certfile=None, ca_certs=None, cert_verify_cb=None, ssl_version="ssl23", tls_level="tls_compat")
+        Start TLS negotiation as per RFC 2595."""
+
+        name = 'STARTTLS'
+
+        if name not in self.capabilities:
+            raise self.abort('TLS not supported by server')
+
+        if self._tls_established:
+            raise self.abort('TLS session already established')
+
+        # Must now shutdown reader thread after next response, and restart after changing read_fd
+
+        self.read_size = 1                # Don't consume TLS handshake
+        self.TerminateReader = True
+
+        try:
+            typ, dat = self._simple_command(name)
+        finally:
+            self._release_state_change()
+            self.rdth.join()
+            self.TerminateReader = False
+            self.read_size = READ_SIZE
+
+        if typ != 'OK':
+            # Restart reader thread and error
+            self.rdth = threading.Thread(target=self._reader)
+            self.rdth.setDaemon(True)
+            self.rdth.start()
+            raise self.error("Couldn't establish TLS session: %s" % dat)
+
+        self.keyfile = keyfile
+        self.certfile = certfile
+        self.ca_certs = ca_certs
+        self.cert_verify_cb = cert_verify_cb
+        self.ssl_version = ssl_version
+        self.tls_level = tls_level
+
+        try:
+            self.ssl_wrap_socket()
+        finally:
+            # Restart reader thread
+            self.rdth = threading.Thread(target=self._reader)
+            self.rdth.setDaemon(True)
+            self.rdth.start()
+
+        self._get_capabilities()
+
+        self._tls_established = True
+
+        typ, dat = self._untagged_response(typ, dat, name)
+        return self._deliver_dat(typ, dat, kw)
+
+
+    def status(self, mailbox, names, **kw):
+        """(typ, [data]) = status(mailbox, names)
+        Request named status conditions for mailbox."""
+
+        name = 'STATUS'
+        kw['untagged_response'] = name
+        return self._simple_command(name, mailbox, names, **kw)
+
+
+    def store(self, message_set, command, flags, **kw):
+        """(typ, [data]) = store(message_set, command, flags)
+        Alters flag dispositions for messages in mailbox."""
+
+        if (flags[0],flags[-1]) != ('(',')'):
+            flags = '(%s)' % flags  # Avoid quoting the flags
+        kw['untagged_response'] = 'FETCH'
+        return self._simple_command('STORE', message_set, command, flags, **kw)
+
+
+    def subscribe(self, mailbox, **kw):
+        """(typ, [data]) = subscribe(mailbox)
+        Subscribe to new mailbox."""
+
+        try:
+            return self._simple_command('SUBSCRIBE', mailbox, **kw)
+        finally:
+            self._release_state_change()
+
+
+    def thread(self, threading_algorithm, charset, *search_criteria, **kw):
+        """(type, [data]) = thread(threading_alogrithm, charset, search_criteria, ...)
+        IMAPrev1 extension THREAD command."""
+
+        name = 'THREAD'
+        kw['untagged_response'] = name
+        return self._simple_command(name, threading_algorithm, charset, *search_criteria, **kw)
+
+
+    def uid(self, command, *args, **kw):
+        """(typ, [data]) = uid(command, arg, ...)
+        Execute "command arg ..." with messages identified by UID,
+            rather than message number.
+        Assumes 'command' is legal in current state.
+        Returns response appropriate to 'command'."""
+
+        command = command.upper()
+        if command in UID_direct:
+            resp = command
+        else:
+            resp = 'FETCH'
+        kw['untagged_response'] = resp
+        return self._simple_command('UID', command, *args, **kw)
+
+
+    def unsubscribe(self, mailbox, **kw):
+        """(typ, [data]) = unsubscribe(mailbox)
+        Unsubscribe from old mailbox."""
+
+        try:
+            return self._simple_command('UNSUBSCRIBE', mailbox, **kw)
+        finally:
+            self._release_state_change()
+
+
+    def xatom(self, name, *args, **kw):
+        """(typ, [data]) = xatom(name, arg, ...)
+        Allow simple extension commands notified by server in CAPABILITY response.
+        Assumes extension command 'name' is legal in current state.
+        Returns response appropriate to extension command 'name'."""
+
+        name = name.upper()
+        if not name in Commands:
+            Commands[name] = ((self.state,), False)
+        try:
+            return self._simple_command(name, *args, **kw)
+        finally:
+            self._release_state_change()
+
+
+
+    #       Internal methods
+
+
+    def _append_untagged(self, typ, dat):
+
+        # Append new 'dat' to end of last untagged response if same 'typ',
+        # else append new response.
+
+        if dat is None: dat = b''
+
+        self.commands_lock.acquire()
+
+        if self.untagged_responses:
+            urn, urd = self.untagged_responses[-1]
+            if urn != typ:
+                 urd = None
+        else:
+            urd = None
+
+        if urd is None:
+            urd = []
+            self.untagged_responses.append([typ, urd])
+
+        urd.append(dat)
+
+        self.commands_lock.release()
+
+        if __debug__: self._log(5, 'untagged_responses[%s] %s += ["%.80r"]' % (typ, len(urd)-1, dat))
+
+
+    def _check_bye(self):
+
+        bye = self._get_untagged_response('BYE', leave=True)
+        if bye:
+            raise self.abort(bye[-1].decode('ASCII', 'replace'))
+
+
+    def _choose_nonull_or_dflt(self, dflt, *args):
+        if isinstance(dflt, str):
+            dflttyp = str            # Allow any string type
+        else:
+            dflttyp = type(dflt)
+        for arg in args:
+            if arg is not None:
+                 if isinstance(arg, dflttyp):
+                     return arg
+                 if __debug__: self._log(0, 'bad arg is %s, expecting %s' % (type(arg), dflttyp))
+        return dflt
+
+
+    def _command(self, name, *args, **kw):
+
+        if Commands[name][CMD_VAL_ASYNC]:
+            cmdtyp = 'async'
+        else:
+            cmdtyp = 'sync'
+
+        if __debug__: self._log(1, '[%s] %s %s' % (cmdtyp, name, args))
+
+        if __debug__: self._log(3, 'state_change_pending.acquire')
+        self.state_change_pending.acquire()
+
+        self._end_idle()
+
+        if cmdtyp == 'async':
+            self.state_change_pending.release()
+            if __debug__: self._log(3, 'state_change_pending.release')
+        else:
+            # Need to wait for all async commands to complete
+            self._check_bye()
+            self.commands_lock.acquire()
+            if self.tagged_commands:
+                self.state_change_free.clear()
+                need_event = True
+            else:
+                need_event = False
+            self.commands_lock.release()
+            if need_event:
+                if __debug__: self._log(3, 'sync command %s waiting for empty commands Q' % name)
+                self.state_change_free.wait()
+                if __debug__: self._log(3, 'sync command %s proceeding' % name)
+
+        if self.state not in Commands[name][CMD_VAL_STATES]:
+            self.literal = None
+            raise self.error('command %s illegal in state %s'
+                                % (name, self.state))
+
+        self._check_bye()
+
+        if name in ('EXAMINE', 'SELECT'):
+            self.commands_lock.acquire()
+            self.untagged_responses = []      # Flush all untagged responses
+            self.commands_lock.release()
+        else:
+            for typ in ('OK', 'NO', 'BAD'):
+                while self._get_untagged_response(typ):
+                    continue
+
+            if not self.is_readonly and self._get_untagged_response('READ-ONLY', leave=True):
+                self.literal = None
+                raise self.readonly('mailbox status changed to READ-ONLY')
+
+        if self.Terminate:
+            raise self.abort('connection closed')
+
+        rqb = self._request_push(name=name, **kw)
+
+        name = bytes(name, self._encoding)
+        data = rqb.tag + b' ' + name
+        for arg in args:
+            if arg is None: continue
+            if isinstance(arg, str):
+                arg = bytes(arg, self._encoding)
+            data = data + b' ' + arg
+
+        literal = self.literal
+        if literal is not None:
+            self.literal = None
+            if type(literal) is type(self._command):
+                literator = literal
+            else:
+                literator = None
+                data = data + bytes(' {%s}' % len(literal), self._encoding)
+
+        if __debug__: self._log(4, 'data=%r' % data)
+
+        rqb.data = data + CRLF
+
+        if literal is None:
+            self.ouq.put(rqb)
+            return rqb
+
+        # Must setup continuation expectancy *before* ouq.put
+        crqb = self._request_push(name=name, tag='continuation')
+
+        self.ouq.put(rqb)
+
+        while True:
+            # Wait for continuation response
+
+            ok, data = crqb.get_response('command: %s => %%s' % name)
+            if __debug__: self._log(4, 'continuation => %s, %r' % (ok, data))
+
+            # NO/BAD response?
+
+            if not ok:
+                break
+
+            if data == 'go ahead':  # Apparently not uncommon broken IMAP4 server response to AUTHENTICATE command
+                data = ''
+
+            # Send literal
+
+            if literator is not None:
+                literal = literator(data, rqb)
+
+            if literal is None:
+                break
+
+            if literator is not None:
+                # Need new request for next continuation response
+                crqb = self._request_push(name=name, tag='continuation')
+
+            if __debug__: self._log(4, 'write literal size %s' % len(literal))
+            crqb.data = literal + CRLF
+            self.ouq.put(crqb)
+
+            if literator is None:
+                break
+
+        return rqb
+
+
+    def _command_complete(self, rqb, kw):
+
+        # Called for non-callback commands
+
+        self._check_bye()
+        typ, dat = rqb.get_response('command: %s => %%s' % rqb.name)
+        if typ == 'BAD':
+            if __debug__: self._print_log()
+            raise self.error('%s command error: %s %s. Data: %.100s' % (rqb.name, typ, dat, rqb.data))
+        if 'untagged_response' in kw:
+            return self._untagged_response(typ, dat, kw['untagged_response'])
+        return typ, dat
+
+
+    def _command_completer(self, cb_arg_list):
+
+        # Called for callback commands
+        response, cb_arg, error = cb_arg_list
+        rqb, kw = cb_arg
+        rqb.callback = kw['callback']
+        rqb.callback_arg = kw.get('cb_arg')
+        if error is not None:
+            if __debug__: self._print_log()
+            typ, val = error
+            rqb.abort(typ, val)
+            return
+        bye = self._get_untagged_response('BYE', leave=True)
+        if bye:
+            rqb.abort(self.abort, bye[-1].decode('ASCII', 'replace'))
+            return
+        typ, dat = response
+        if typ == 'BAD':
+            if __debug__: self._print_log()
+            rqb.abort(self.error, '%s command error: %s %s. Data: %.100s' % (rqb.name, typ, dat, rqb.data))
+            return
+        if __debug__: self._log(4, '_command_completer(%s, %s, None) = %s' % (response, cb_arg, rqb.tag))
+        if 'untagged_response' in kw:
+            response = self._untagged_response(typ, dat, kw['untagged_response'])
+        rqb.deliver(response)
+
+
+    def _deliver_dat(self, typ, dat, kw):
+
+        if 'callback' in kw:
+            kw['callback'](((typ, dat), kw.get('cb_arg'), None))
+        return typ, dat
+
+
+    def _deliver_exc(self, exc, dat, kw):
+
+        if 'callback' in kw:
+            kw['callback']((None, kw.get('cb_arg'), (exc, dat)))
+        raise exc(dat)
+
+
+    def _end_idle(self):
+
+        self.idle_lock.acquire()
+        irqb = self.idle_rqb
+        if irqb is None:
+            self.idle_lock.release()
+            return
+        self.idle_rqb = None
+        self.idle_timeout = None
+        self.idle_lock.release()
+        irqb.data = bytes('DONE', 'ASCII') + CRLF
+        self.ouq.put(irqb)
+        if __debug__: self._log(2, 'server IDLE finished')
+
+
+    def _get_capabilities(self):
+        typ, dat = self.capability()
+        if dat == [None]:
+            raise self.error('no CAPABILITY response from server')
+        dat = str(dat[-1], "ASCII")
+        dat = dat.upper()
+        self.capabilities = tuple(dat.split())
+
+
+    def _get_untagged_response(self, name, leave=False):
+
+        self.commands_lock.acquire()
+
+        for i, (typ, dat) in enumerate(self.untagged_responses):
+            if typ == name:
+                if not leave:
+                    del self.untagged_responses[i]
+                self.commands_lock.release()
+                if __debug__: self._log(5, '_get_untagged_response(%s) => %.80r' % (name, dat))
+                return dat
+
+        self.commands_lock.release()
+        return None
+
+
+    def _match(self, cre, s):
+
+        # Run compiled regular expression 'cre' match method on 's'.
+        # Save result, return success.
+
+        self.mo = cre.match(s)
+        return self.mo is not None
+
+
+    def _put_response(self, resp):
+
+        if self._expecting_data:
+            rlen = len(resp)
+            dlen = min(self._expecting_data_len, rlen)
+            if __debug__: self._log(5, '_put_response expecting data len %s, got %s' % (self._expecting_data_len, rlen))
+            self._expecting_data_len -= dlen
+            self._expecting_data = (self._expecting_data_len != 0)
+            if rlen <= dlen:
+                self._accumulated_data.append(resp)
+                return
+            self._accumulated_data.append(resp[:dlen])
+            resp = resp[dlen:]
+
+        if self._accumulated_data:
+            typ, dat = self._literal_expected
+            self._append_untagged(typ, (dat, b''.join(self._accumulated_data)))
+            self._accumulated_data = []
+
+        # Protocol mandates all lines terminated by CRLF
+        resp = resp[:-2]
+        if __debug__: self._log(5, '_put_response(%r)' % resp)
+
+        if 'continuation' in self.tagged_commands:
+            continuation_expected = True
+        else:
+            continuation_expected = False
+
+        if self._literal_expected is not None:
+            dat = resp
+            if self._match(self.literal_cre, dat):
+                self._literal_expected[1] = dat
+                self._expecting_data = True
+                self._expecting_data_len = int(self.mo.group('size'))
+                if __debug__: self._log(4, 'expecting literal size %s' % self._expecting_data_len)
+                return
+            typ = self._literal_expected[0]
+            self._literal_expected = None
+            if dat:
+                self._append_untagged(typ, dat)  # Tail
+            if __debug__: self._log(4, 'literal completed')
+        else:
+            # Command completion response?
+            if self._match(self.tagre, resp):
+                tag = self.mo.group('tag')
+                typ = str(self.mo.group('type'), 'ASCII')
+                dat = self.mo.group('data')
+                if typ in ('OK', 'NO', 'BAD') and self._match(self.response_code_cre, dat):
+                    self._append_untagged(str(self.mo.group('type'), 'ASCII'), self.mo.group('data'))
+                if not tag in self.tagged_commands:
+                    if __debug__: self._log(1, 'unexpected tagged response: %r' % resp)
+                else:
+                    self._request_pop(tag, (typ, [dat]))
+            else:
+                dat2 = None
+
+                # '*' (untagged) responses?
+
+                if not self._match(self.untagged_response_cre, resp):
+                    if self._match(self.untagged_status_cre, resp):
+                        dat2 = self.mo.group('data2')
+
+                if self.mo is None:
+                    # Only other possibility is '+' (continuation) response...
+
+                    if self._match(self.continuation_cre, resp):
+                        if not continuation_expected:
+                            if __debug__: self._log(1, "unexpected continuation response: '%r'" % resp)
+                            return
+                        self._request_pop('continuation', (True, self.mo.group('data')))
+                        return
+
+                    if __debug__: self._log(1, "unexpected response: '%r'" % resp)
+                    return
+
+                typ = str(self.mo.group('type'), 'ASCII')
+                dat = self.mo.group('data')
+                if dat is None: dat = b''        # Null untagged response
+                if dat2: dat = dat + b' ' + dat2
+
+                # Is there a literal to come?
+
+                if self._match(self.literal_cre, dat):
+                    self._expecting_data = True
+                    self._expecting_data_len = int(self.mo.group('size'))
+                    if __debug__: self._log(4, 'read literal size %s' % self._expecting_data_len)
+                    self._literal_expected = [typ, dat]
+                    return
+
+                self._append_untagged(typ, dat)
+                if typ in ('OK', 'NO', 'BAD') and self._match(self.response_code_cre, dat):
+                    self._append_untagged(str(self.mo.group('type'), 'ASCII'), self.mo.group('data'))
+
+                if typ != 'OK':                 # NO, BYE, IDLE
+                    self._end_idle()
+
+        # Command waiting for aborted continuation response?
+
+        if continuation_expected:
+            self._request_pop('continuation', (False, resp))
+
+        # Bad news?
+
+        if typ in ('NO', 'BAD', 'BYE'):
+            if typ == 'BYE':
+                self.Terminate = True
+            if __debug__: self._log(1, '%s response: %r' % (typ, dat))
+
+
+    def _quote(self, arg):
+
+        return '"%s"' % arg.replace('\\', '\\\\').replace('"', '\\"')
+
+
+    def _release_state_change(self):
+
+        if self.state_change_pending.locked():
+            self.state_change_pending.release()
+            if __debug__: self._log(3, 'state_change_pending.release')
+
+
+    def _request_pop(self, name, data):
+
+        self.commands_lock.acquire()
+        rqb = self.tagged_commands.pop(name)
+        if not self.tagged_commands:
+            need_event = True
+        else:
+            need_event = False
+        self.commands_lock.release()
+
+        if __debug__: self._log(4, '_request_pop(%s, %r) [%d] = %s' % (name, data, len(self.tagged_commands), rqb.tag))
+        rqb.deliver(data)
+
+        if need_event:
+            if __debug__: self._log(3, 'state_change_free.set')
+            self.state_change_free.set()
+
+
+    def _request_push(self, tag=None, name=None, **kw):
+
+        self.commands_lock.acquire()
+        rqb = Request(self, name=name, **kw)
+        if tag is None:
+            tag = rqb.tag
+        self.tagged_commands[tag] = rqb
+        self.commands_lock.release()
+        if __debug__: self._log(4, '_request_push(%s, %s, %s) = %s' % (tag, name, repr(kw), rqb.tag))
+        return rqb
+
+
+    def _simple_command(self, name, *args, **kw):
+
+        if 'callback' in kw:
+            # Note: old calling sequence for back-compat with python <2.6
+            self._command(name, callback=self._command_completer, cb_arg=kw, cb_self=True, *args)
+            return (None, None)
+        return self._command_complete(self._command(name, *args), kw)
+
+
+    def _untagged_response(self, typ, dat, name):
+
+        if typ == 'NO':
+            return typ, dat
+        data = self._get_untagged_response(name)
+        if not data:
+            return typ, [None]
+        while True:
+            dat = self._get_untagged_response(name)
+            if not dat:
+                break
+            data += dat
+        if __debug__: self._log(4, '_untagged_response(%s, ?, %s) => %.80r' % (typ, name, data))
+        return typ, data
+
+
+
+    #       Threads
+
+
+    def _close_threads(self):
+
+        if __debug__: self._log(1, '_close_threads')
+
+        self.ouq.put(None)
+        self.wrth.join()
+
+        if __debug__: self._log(1, 'call shutdown')
+
+        self.shutdown()
+
+        self.rdth.join()
+        self.inth.join()
+
+
+    def _handler(self):
+
+        resp_timeout = self.resp_timeout
+
+        threading.currentThread().setName(self.identifier + 'handler')
+
+        time.sleep(0.1)   # Don't start handling before main thread ready
+
+        if __debug__: self._log(1, 'starting')
+
+        typ, val = self.abort, 'connection terminated'
+
+        while not self.Terminate:
+
+            self.idle_lock.acquire()
+            if self.idle_timeout is not None:
+                timeout = self.idle_timeout - time.time()
+                if timeout <= 0:
+                    timeout = 1
+                if __debug__:
+                    if self.idle_rqb is not None:
+                        self._log(5, 'server IDLING, timeout=%.2f' % timeout)
+            else:
+                timeout = resp_timeout
+            self.idle_lock.release()
+
+            try:
+                line = self.inq.get(True, timeout)
+            except queue.Empty:
+                if self.idle_rqb is None:
+                    if resp_timeout is not None and self.tagged_commands:
+                        if __debug__: self._log(1, 'response timeout')
+                        typ, val = self.abort, 'no response after %s secs' % resp_timeout
+                        break
+                    continue
+                if self.idle_timeout > time.time():
+                    continue
+                if __debug__: self._log(2, 'server IDLE timedout')
+                line = IDLE_TIMEOUT_RESPONSE
+
+            if line is None:
+                if __debug__: self._log(1, 'inq None - terminating')
+                break
+
+            if not isinstance(line, bytes):
+                typ, val = line
+                break
+
+            try:
+                self._put_response(line)
+            except:
+                typ, val = self.error, 'program error: %s - %s' % sys.exc_info()[:2]
+                break
+
+        self.Terminate = True
+
+        if __debug__: self._log(1, 'terminating: %s' % repr(val))
+
+        while not self.ouq.empty():
+            try:
+                qel = self.ouq.get_nowait()
+                if qel is not None:
+                    qel.abort(typ, val)
+            except queue.Empty:
+                break
+        self.ouq.put(None)
+
+        self.commands_lock.acquire()
+        for name in list(self.tagged_commands.keys()):
+            rqb = self.tagged_commands.pop(name)
+            rqb.abort(typ, val)
+        self.state_change_free.set()
+        self.commands_lock.release()
+        if __debug__: self._log(3, 'state_change_free.set')
+
+        if __debug__: self._log(1, 'finished')
+
+
+    if hasattr(select_module, "poll"):
+
+      def _reader(self):
+
+        threading.currentThread().setName(self.identifier + 'reader')
+
+        if __debug__: self._log(1, 'starting using poll')
+
+        def poll_error(state):
+            PollErrors = {
+                select.POLLERR:     'Error',
+                select.POLLHUP:     'Hang up',
+                select.POLLNVAL:    'Invalid request: descriptor not open',
+            }
+            return ' '.join([PollErrors[s] for s in PollErrors.keys() if (s & state)])
+
+        line_part = b''
+
+        poll = select.poll()
+
+        poll.register(self.read_fd, select.POLLIN)
+
+        rxzero = 0
+        terminate = False
+        read_poll_timeout = self.read_poll_timeout * 1000       # poll() timeout is in millisecs
+
+        while not (terminate or self.Terminate):
+            if self.state == LOGOUT:
+                timeout = 10
+            else:
+                timeout = read_poll_timeout
+            try:
+                r = poll.poll(timeout)
+                if __debug__: self._log(5, 'poll => %s' % repr(r))
+                if not r:
+                    continue                                    # Timeout
+
+                fd,state = r[0]
+
+                if state & select.POLLIN:
+                    data = self.read(self.read_size)            # Drain ssl buffer if present
+                    start = 0
+                    dlen = len(data)
+                    if __debug__: self._log(5, 'rcvd %s' % dlen)
+                    if dlen == 0:
+                        rxzero += 1
+                        if rxzero > 5:
+                            raise IOError("Too many read 0")
+                        time.sleep(0.1)
+                        continue                                # Try again
+                    rxzero = 0
+
+                    while True:
+                        stop = data.find(b'\n', start)
+                        if stop < 0:
+                            line_part += data[start:]
+                            break
+                        stop += 1
+                        line_part, start, line = \
+                            b'', stop, line_part + data[start:stop]
+                        if __debug__: self._log(4, '< %r' % line)
+                        self.inq.put(line)
+                        if self.TerminateReader:
+                            terminate = True
+
+                if state & ~(select.POLLIN):
+                    raise IOError(poll_error(state))
+            except:
+                reason = 'socket error: %s - %s' % sys.exc_info()[:2]
+                if __debug__:
+                    if not self.Terminate:
+                        self._print_log()
+                        if self.debug: self.debug += 4          # Output all
+                        self._log(1, reason)
+                self.inq.put((self.abort, reason))
+                break
+
+        poll.unregister(self.read_fd)
+
+        if __debug__: self._log(1, 'finished')
+
+    else:
+
+      # No "poll" - use select()
+
+      def _reader(self):
+
+        threading.currentThread().setName(self.identifier + 'reader')
+
+        if __debug__: self._log(1, 'starting using select')
+
+        line_part = b''
+
+        rxzero = 0
+        terminate = False
+
+        while not (terminate or self.Terminate):
+            if self.state == LOGOUT:
+                timeout = 1
+            else:
+                timeout = self.read_poll_timeout
+            try:
+                r,w,e = select.select([self.read_fd], [], [], timeout)
+                if __debug__: self._log(5, 'select => %s, %s, %s' % (r,w,e))
+                if not r:                                       # Timeout
+                    continue
+
+                data = self.read(self.read_size)                # Drain ssl buffer if present
+                start = 0
+                dlen = len(data)
+                if __debug__: self._log(5, 'rcvd %s' % dlen)
+                if dlen == 0:
+                    rxzero += 1
+                    if rxzero > 5:
+                        raise IOError("Too many read 0")
+                    time.sleep(0.1)
+                    continue                                    # Try again
+                rxzero = 0
+
+                while True:
+                    stop = data.find(b'\n', start)
+                    if stop < 0:
+                        line_part += data[start:]
+                        break
+                    stop += 1
+                    line_part, start, line = \
+                        b'', stop, (line_part + data[start:stop]).decode(errors='ignore')
+                    if __debug__: self._log(4, '< %r' % line)
+                    self.inq.put(line)
+                    if self.TerminateReader:
+                        terminate = True
+            except:
+                reason = 'socket error: %s - %s' % sys.exc_info()[:2]
+                if __debug__:
+                    if not self.Terminate:
+                        self._print_log()
+                        if self.debug: self.debug += 4          # Output all
+                        self._log(1, reason)
+                self.inq.put((self.abort, reason))
+                break
+
+        if __debug__: self._log(1, 'finished')
+
+
+    def _writer(self):
+
+        threading.currentThread().setName(self.identifier + 'writer')
+
+        if __debug__: self._log(1, 'starting')
+
+        reason = 'Terminated'
+
+        while not self.Terminate:
+            rqb = self.ouq.get()
+            if rqb is None:
+                break   # Outq flushed
+
+            try:
+                self.send(rqb.data)
+                if __debug__: self._log(4, '> %r' % rqb.data)
+            except:
+                reason = 'socket error: %s - %s' % sys.exc_info()[:2]
+                if __debug__:
+                    if not self.Terminate:
+                        self._print_log()
+                        if self.debug: self.debug += 4          # Output all
+                        self._log(1, reason)
+                rqb.abort(self.abort, reason)
+                break
+
+        self.inq.put((self.abort, reason))
+
+        if __debug__: self._log(1, 'finished')
+
+
+
+    #       Debugging
+
+
+    if __debug__:
+
+        def _init_debug(self, debug=None, debug_file=None, debug_buf_lvl=None):
+            self.debug_lock = threading.Lock()
+
+            self.debug = self._choose_nonull_or_dflt(0, debug)
+            self.debug_file = self._choose_nonull_or_dflt(sys.stderr, debug_file)
+            self.debug_buf_lvl = self._choose_nonull_or_dflt(DFLT_DEBUG_BUF_LVL, debug_buf_lvl)
+
+            self._cmd_log_len = 20
+            self._cmd_log_idx = 0
+            self._cmd_log = {}           # Last `_cmd_log_len' interactions
+            if self.debug:
+                self._mesg('imaplib2 version %s' % __version__)
+                self._mesg('imaplib2 debug level %s, buffer level %s' % (self.debug, self.debug_buf_lvl))
+
+
+        def _dump_ur(self, lvl):
+            if lvl > self.debug:
+                return
+
+            l = self.untagged_responses  # NB: bytes array
+            if not l:
+                return
+
+            t = '\n\t\t'
+            l = ['%s: "%s"' % (x[0], x[1][0] and b'" "'.join(x[1]) or '') for x in l]
+            self.debug_lock.acquire()
+            self._mesg('untagged responses dump:%s%s' % (t, t.join(l)))
+            self.debug_lock.release()
+
+
+        def _log(self, lvl, line):
+            if lvl > self.debug:
+                return
+
+            if line[-2:] == CRLF:
+                line = line[:-2] + '\\r\\n'
+
+            tn = threading.currentThread().getName()
+
+            if lvl <= 1 or self.debug > self.debug_buf_lvl:
+                self.debug_lock.acquire()
+                self._mesg(line, tn)
+                self.debug_lock.release()
+                if lvl != 1:
+                    return
+
+            # Keep log of last `_cmd_log_len' interactions for debugging.
+            self.debug_lock.acquire()
+            self._cmd_log[self._cmd_log_idx] = (line, tn, time.time())
+            self._cmd_log_idx += 1
+            if self._cmd_log_idx >= self._cmd_log_len:
+                self._cmd_log_idx = 0
+            self.debug_lock.release()
+
+
+        def _mesg(self, s, tn=None, secs=None):
+            if secs is None:
+                secs = time.time()
+            if tn is None:
+                tn = threading.currentThread().getName()
+            tm = time.strftime('%M:%S', time.localtime(secs))
+            try:
+                self.debug_file.write('  %s.%02d %s %s\n' % (tm, (secs*100)%100, tn, s))
+                self.debug_file.flush()
+            finally:
+                pass
+
+
+        def _print_log(self):
+            self.debug_lock.acquire()
+            i, n = self._cmd_log_idx, self._cmd_log_len
+            if n: self._mesg('last %d log messages:' % n)
+            while n:
+                try:
+                    self._mesg(*self._cmd_log[i])
+                except:
+                    pass
+                i += 1
+                if i >= self._cmd_log_len:
+                    i = 0
+                n -= 1
+            self.debug_lock.release()
+
+
+
+class IMAP4_SSL(IMAP4):
+
+    """IMAP4 client class over SSL connection
+
+    Instantiate with:
+        IMAP4_SSL(host=None, port=None, keyfile=None, certfile=None, ca_certs=None, cert_verify_cb=None, ssl_version="ssl23", debug=None, debug_file=None, identifier=None, timeout=None, debug_buf_lvl=None, tls_level="tls_compat")
+
+        host           - host's name (default: localhost);
+        port           - port number (default: standard IMAP4 SSL port);
+        keyfile        - PEM formatted file that contains your private key (default: None);
+        certfile       - PEM formatted certificate chain file (default: None);
+        ca_certs       - PEM formatted certificate chain file used to validate server certificates (default: None);
+        cert_verify_cb - function to verify authenticity of server certificates (default: None);
+        ssl_version    - SSL version to use (default: "ssl23", choose from: "tls1","ssl3","ssl23");
+        debug          - debug level (default: 0 - no debug);
+        debug_file     - debug stream (default: sys.stderr);
+        identifier     - thread identifier prefix (default: host);
+        timeout        - timeout in seconds when expecting a command response.
+        debug_buf_lvl  - debug level at which buffering is turned off.
+        tls_level      - TLS security level (default: "tls_compat").
+
+    The recognized values for tls_level are:
+        tls_secure: accept only TLS protocols recognized as "secure"
+        tls_no_ssl: disable SSLv2 and SSLv3 support
+        tls_compat: accept all SSL/TLS versions
+
+    For more documentation see the docstring of the parent class IMAP4.
+    """
+
+
+    def __init__(self, host=None, port=None, keyfile=None, certfile=None, ca_certs=None, cert_verify_cb=None, ssl_version="ssl23", debug=None, debug_file=None, identifier=None, timeout=None, debug_buf_lvl=None, tls_level=TLS_COMPAT):
+        self.keyfile = keyfile
+        self.certfile = certfile
+        self.ca_certs = ca_certs
+        self.cert_verify_cb = cert_verify_cb
+        self.ssl_version = ssl_version
+        self.tls_level = tls_level
+        IMAP4.__init__(self, host, port, debug, debug_file, identifier, timeout, debug_buf_lvl)
+
+
+    def open(self, host=None, port=None):
+        """open(host=None, port=None)
+        Setup secure connection to remote server on "host:port"
+            (default: localhost:standard IMAP4 SSL port).
+        This connection will be used by the routines:
+            read, send, shutdown, socket, ssl."""
+
+        self.host = self._choose_nonull_or_dflt('', host)
+        self.port = self._choose_nonull_or_dflt(IMAP4_SSL_PORT, port)
+        self.sock = self.open_socket()
+        self.ssl_wrap_socket()
+
+
+    def read(self, size):
+        """data = read(size)
+        Read at most 'size' bytes from remote."""
+
+        if self.decompressor is None:
+            return self.sock.read(size)
+
+        if self.decompressor.unconsumed_tail:
+            data = self.decompressor.unconsumed_tail
+        else:
+            data = self.sock.read(READ_SIZE)
+
+        return self.decompressor.decompress(data, size)
+
+
+    def send(self, data):
+        """send(data)
+        Send 'data' to remote."""
+
+        if self.compressor is not None:
+            data = self.compressor.compress(data)
+            data += self.compressor.flush(zlib.Z_SYNC_FLUSH)
+
+        if hasattr(self.sock, "sendall"):
+            self.sock.sendall(data)
+        else:
+            dlen = len(data)
+            while dlen > 0:
+                sent = self.sock.write(data)
+                if sent == dlen:
+                    break    # avoid copy
+                data = data[sent:]
+                dlen = dlen - sent
+
+
+    def ssl(self):
+        """ssl = ssl()
+        Return ssl instance used to communicate with the IMAP4 server."""
+
+        return self.sock
+
+
+
+class IMAP4_stream(IMAP4):
+
+    """IMAP4 client class over a stream
+
+    Instantiate with:
+        IMAP4_stream(command, debug=None, debug_file=None, identifier=None, timeout=None, debug_buf_lvl=None)
+
+        command        - string that can be passed to subprocess.Popen();
+        debug          - debug level (default: 0 - no debug);
+        debug_file     - debug stream (default: sys.stderr);
+        identifier     - thread identifier prefix (default: host);
+        timeout        - timeout in seconds when expecting a command response.
+        debug_buf_lvl  - debug level at which buffering is turned off.
+
+    For more documentation see the docstring of the parent class IMAP4.
+    """
+
+
+    def __init__(self, command, debug=None, debug_file=None, identifier=None, timeout=None, debug_buf_lvl=None):
+        self.command = command
+        self.host = command
+        self.port = None
+        self.sock = None
+        self.writefile, self.readfile = None, None
+        self.read_fd = None
+        IMAP4.__init__(self, None, None, debug, debug_file, identifier, timeout, debug_buf_lvl)
+
+
+    def open(self, host=None, port=None):
+        """open(host=None, port=None)
+        Setup a stream connection via 'self.command'.
+        This connection will be used by the routines:
+            read, send, shutdown, socket."""
+
+        from subprocess import Popen, PIPE
+        from io import DEFAULT_BUFFER_SIZE
+
+        if __debug__: self._log(0, 'opening stream from command "%s"' % self.command)
+        self._P = Popen(self.command, shell=True, stdin=PIPE, stdout=PIPE, close_fds=True, bufsize=DEFAULT_BUFFER_SIZE)
+        self.writefile, self.readfile = self._P.stdin, self._P.stdout
+        self.read_fd = self.readfile.fileno()
+
+
+    def read(self, size):
+        """Read 'size' bytes from remote."""
+
+        if self.decompressor is None:
+            return os.read(self.read_fd, size)
+
+        if self.decompressor.unconsumed_tail:
+            data = self.decompressor.unconsumed_tail
+        else:
+            data = os.read(self.read_fd, READ_SIZE)
+
+        return self.decompressor.decompress(data, size)
+
+
+    def send(self, data):
+        """Send data to remote."""
+
+        if self.compressor is not None:
+            data = self.compressor.compress(data)
+            data += self.compressor.flush(zlib.Z_SYNC_FLUSH)
+
+        self.writefile.write(data)
+        self.writefile.flush()
+
+
+    def shutdown(self):
+        """Close I/O established in "open"."""
+
+        self.readfile.close()
+        self.writefile.close()
+        self._P.wait()
+
+
+class _Authenticator(object):
+
+    """Private class to provide en/de-coding
+    for base64 authentication conversation."""
+
+    def __init__(self, mechinst):
+        self.mech = mechinst    # Callable object to provide/process data
+
+    def process(self, data, rqb):
+        ret = self.mech(self.decode(data))
+        if ret is None:
+            return b'*'         # Abort conversation
+        return self.encode(ret)
+
+    def encode(self, inp):
+        #
+        #  Invoke binascii.b2a_base64 iteratively with
+        #  short even length buffers, strip the trailing
+        #  line feed from the result and append.  "Even"
+        #  means a number that factors to both 6 and 8,
+        #  so when it gets to the end of the 8-bit input
+        #  there's no partial 6-bit output.
+        #
+        oup = b''
+        if isinstance(inp, str):
+            inp = inp.encode('utf-8')
+        while inp:
+            if len(inp) > 48:
+                t = inp[:48]
+                inp = inp[48:]
+            else:
+                t = inp
+                inp = b''
+            e = binascii.b2a_base64(t)
+            if e:
+                oup = oup + e[:-1]
+        return oup
+
+    def decode(self, inp):
+        if not inp:
+            return b''
+        return binascii.a2b_base64(inp)
+
+
+
+
+class _IdleCont(object):
+
+    """When process is called, server is in IDLE state
+    and will send asynchronous changes."""
+
+    def __init__(self, parent, timeout):
+        self.parent = parent
+        self.timeout = parent._choose_nonull_or_dflt(IDLE_TIMEOUT, timeout)
+        self.parent.idle_timeout = self.timeout + time.time()
+
+    def process(self, data, rqb):
+        self.parent.idle_lock.acquire()
+        self.parent.idle_rqb = rqb
+        self.parent.idle_timeout = self.timeout + time.time()
+        self.parent.idle_lock.release()
+        if __debug__: self.parent._log(2, 'server IDLE started, timeout in %.2f secs' % self.timeout)
+        return None
+
+
+
+MonthNames = [None, 'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun',
+                'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec']
+
+Mon2num = {s.encode():n+1 for n, s in enumerate(MonthNames[1:])}
+
+InternalDate = re.compile(br'.*INTERNALDATE "'
+    br'(?P<day>[ 0123][0-9])-(?P<mon>[A-Z][a-z][a-z])-(?P<year>[0-9][0-9][0-9][0-9])'
+    br' (?P<hour>[0-9][0-9]):(?P<min>[0-9][0-9]):(?P<sec>[0-9][0-9])'
+    br' (?P<zonen>[-+])(?P<zoneh>[0-9][0-9])(?P<zonem>[0-9][0-9])'
+    br'"')
+
+
+def Internaldate2Time(resp):
+
+    """time_tuple = Internaldate2Time(resp)
+
+    Parse an IMAP4 INTERNALDATE string.
+
+    Return corresponding local time.  The return value is a
+    time.struct_time instance or None if the string has wrong format."""
+
+    mo = InternalDate.match(resp)
+    if not mo:
+        return None
+
+    mon = Mon2num[mo.group('mon')]
+    zonen = mo.group('zonen')
+
+    day = int(mo.group('day'))
+    year = int(mo.group('year'))
+    hour = int(mo.group('hour'))
+    min = int(mo.group('min'))
+    sec = int(mo.group('sec'))
+    zoneh = int(mo.group('zoneh'))
+    zonem = int(mo.group('zonem'))
+
+    # INTERNALDATE timezone must be subtracted to get UT
+
+    zone = (zoneh*60 + zonem)*60
+    if zonen == b'-':
+        zone = -zone
+
+    tt = (year, mon, day, hour, min, sec, -1, -1, -1)
+    return time.localtime(calendar.timegm(tt) - zone)
+
+Internaldate2tuple = Internaldate2Time   # (Backward compatible)
+
+
+
+def Time2Internaldate(date_time):
+
+    """'"DD-Mmm-YYYY HH:MM:SS +HHMM"' = Time2Internaldate(date_time)
+
+    Convert 'date_time' to IMAP4 INTERNALDATE representation.
+
+    The date_time argument can be a number (int or float) representing
+    seconds since epoch (as returned by time.time()), a 9-tuple
+    representing local time, an instance of time.struct_time (as
+    returned by time.localtime()), an aware datetime instance or a
+    double-quoted string.  In the last case, it is assumed to already
+    be in the correct format."""
+
+    from datetime import datetime, timezone, timedelta
+
+    if isinstance(date_time, (int, float)):
+        tt = time.localtime(date_time)
+    elif isinstance(date_time, tuple):
+        try:
+            gmtoff = date_time.tm_gmtoff
+        except AttributeError:
+            if time.daylight:
+                dst = date_time[8]
+                if dst == -1:
+                    dst = time.localtime(time.mktime(date_time))[8]
+                gmtoff = -(time.timezone, time.altzone)[dst]
+            else:
+                gmtoff = -time.timezone
+        delta = timedelta(seconds=gmtoff)
+        dt = datetime(*date_time[:6], tzinfo=timezone(delta))
+    elif isinstance(date_time, datetime):
+        if date_time.tzinfo is None:
+            raise ValueError("date_time must be aware")
+        dt = date_time
+    elif isinstance(date_time, str) and (date_time[0],date_time[-1]) == ('"','"'):
+        return date_time        # Assume in correct format
+    else:
+        raise ValueError("date_time not of a known type")
+
+    fmt = '"%d-{}-%Y %H:%M:%S %z"'.format(MonthNames[dt.month])
+    return dt.strftime(fmt)
+
+
+
+FLAGS_cre = re.compile(br'.*FLAGS \((?P<flags>[^\)]*)\)')
+
+def ParseFlags(resp):
+
+    """('flag', ...) = ParseFlags(line)
+    Convert IMAP4 flags response to python tuple."""
+
+    mo = FLAGS_cre.match(resp)
+    if not mo:
+        return ()
+
+    return tuple(mo.group('flags').split())
+
+
+
+if __name__ == '__main__':
+
+    # To test: invoke either as 'python imaplib2.py [IMAP4_server_hostname]',
+    # or as 'python imaplib2.py -s "rsh IMAP4_server_hostname exec /etc/rimapd"'
+    # or as 'python imaplib2.py -l keyfile[:certfile]|: [IMAP4_SSL_server_hostname]'
+    #
+    # Option "-d <level>" turns on debugging (use "-d 5" for everything)
+    # Option "-i" tests that IDLE is interruptible
+    # Option "-p <port>" allows alternate ports
+
+    if not __debug__:
+        raise ValueError('Please run without -O')
+
+    import getopt, getpass
+
+    try:
+        optlist, args = getopt.getopt(sys.argv[1:], 'd:il:s:p:')
+    except getopt.error as val:
+        optlist, args = (), ()
+
+    debug, debug_buf_lvl, port, stream_command, keyfile, certfile, idle_intr = (None,)*7
+    for opt,val in optlist:
+        if opt == '-d':
+            debug = int(val)
+            debug_buf_lvl = debug - 1
+        elif opt == '-i':
+            idle_intr = 1
+        elif opt == '-l':
+            try:
+                keyfile,certfile = val.split(':')
+            except ValueError:
+                keyfile,certfile = val,val
+        elif opt == '-p':
+            port = int(val)
+        elif opt == '-s':
+            stream_command = val
+            if not args: args = (stream_command,)
+
+    if not args: args = ('',)
+    if not port: port = (keyfile is not None) and IMAP4_SSL_PORT or IMAP4_PORT
+
+    host = args[0]
+
+    USER = getpass.getuser()
+
+    data = open(os.path.exists("test.data") and "test.data" or __file__).read(1000)
+    test_mesg = 'From: %(user)s@localhost%(lf)sSubject: IMAP4 test%(lf)s%(lf)s%(data)s' \
+                     % {'user':USER, 'lf':'\n', 'data':data}
+
+    test_seq1 = [
+    ('list', ('""', '""')),
+    ('list', ('""', '"%"')),
+    ('create', ('imaplib2_test0',)),
+    ('rename', ('imaplib2_test0', 'imaplib2_test1')),
+    ('CREATE', ('imaplib2_test2',)),
+    ('append', ('imaplib2_test2', None, None, test_mesg)),
+    ('list', ('""', '"imaplib2_test%"')),
+    ('select', ('imaplib2_test2',)),
+    ('search', (None, 'SUBJECT', '"IMAP4 test"')),
+    ('fetch', ('1:*', '(FLAGS INTERNALDATE RFC822)')),
+    ('store', ('1', 'FLAGS', '(\Deleted)')),
+    ('namespace', ()),
+    ('expunge', ()),
+    ('recent', ()),
+    ('close', ()),
+    ]
+
+    test_seq2 = (
+    ('select', ()),
+    ('response', ('UIDVALIDITY',)),
+    ('response', ('EXISTS',)),
+    ('append', (None, None, None, test_mesg)),
+    ('examine', ()),
+    ('select', ()),
+    ('fetch', ('1:*', '(FLAGS UID)')),
+    ('examine', ()),
+    ('select', ()),
+    ('uid', ('SEARCH', 'SUBJECT', '"IMAP4 test"')),
+    ('uid', ('SEARCH', 'ALL')),
+    ('uid', ('THREAD', 'references', 'UTF-8', '(SEEN)')),
+    ('recent', ()),
+    )
+
+
+    AsyncError, M = None, None
+
+    def responder(cb_arg_list):
+        response, cb_arg, error = cb_arg_list
+        global AsyncError
+        cmd, args = cb_arg
+        if error is not None:
+            AsyncError = error
+            M._log(0, '[cb] ERROR %s %.100s => %s' % (cmd, args, error))
+            return
+        typ, dat = response
+        M._log(0, '[cb] %s %.100s => %s %.100s' % (cmd, args, typ, dat))
+        if typ == 'NO':
+            AsyncError = (Exception, dat[0])
+
+    def run(cmd, args, cb=True):
+        if AsyncError:
+            M._log(1, 'AsyncError %s' % repr(AsyncError))
+            M.logout()
+            typ, val = AsyncError
+            raise typ(val)
+        if not M.debug: M._log(0, '%s %.100s' % (cmd, args))
+        try:
+            if cb:
+                typ, dat = getattr(M, cmd)(callback=responder, cb_arg=(cmd, args), *args)
+                M._log(1, '%s %.100s => %s %.100s' % (cmd, args, typ, dat))
+            else:
+                typ, dat = getattr(M, cmd)(*args)
+                M._log(1, '%s %.100s => %s %.100s' % (cmd, args, typ, dat))
+        except:
+            M._log(1, '%s - %s' % sys.exc_info()[:2])
+            M.logout()
+            raise
+        if typ == 'NO':
+            M._log(1, 'NO')
+            M.logout()
+            raise Exception(dat[0])
+        return dat
+
+    try:
+        threading.currentThread().setName('main')
+
+        if keyfile is not None:
+            if not keyfile: keyfile = None
+            if not certfile: certfile = None
+            M = IMAP4_SSL(host=host, port=port, keyfile=keyfile, certfile=certfile, ssl_version="tls1", debug=debug, identifier='', timeout=10, debug_buf_lvl=debug_buf_lvl, tls_level="tls_no_ssl")
+        elif stream_command:
+            M = IMAP4_stream(stream_command, debug=debug, identifier='', timeout=10, debug_buf_lvl=debug_buf_lvl)
+        else:
+            M = IMAP4(host=host, port=port, debug=debug, identifier='', timeout=10, debug_buf_lvl=debug_buf_lvl)
+        if M.state != 'AUTH':   # Login needed
+            PASSWD = getpass.getpass("IMAP password for %s on %s: " % (USER, host or "localhost"))
+            test_seq1.insert(0, ('login', (USER, PASSWD)))
+        M._log(0, 'PROTOCOL_VERSION = %s' % M.PROTOCOL_VERSION)
+        if 'COMPRESS=DEFLATE' in M.capabilities:
+            M.enable_compression()
+
+        for cmd,args in test_seq1:
+            run(cmd, args)
+
+        for ml in run('list', ('""', '"imaplib2_test%"'), cb=False):
+            mo = re.match(br'.*"([^"]+)"$', ml)
+            if mo: path = mo.group(1)
+            else: path = ml.split()[-1]
+            run('delete', (path,))
+
+        if 'ID' in M.capabilities:
+            run('id', ())
+            run('id', ("(name imaplib2)",))
+            run('id', ("version", __version__, "os", os.uname()[0]))
+
+        for cmd,args in test_seq2:
+            if (cmd,args) != ('uid', ('SEARCH', 'SUBJECT', 'IMAP4 test')):
+                run(cmd, args)
+                continue
+
+            dat = run(cmd, args, cb=False)
+            uid = dat[-1].split()
+            if not uid: continue
+            run('uid', ('FETCH', uid[-1],
+                    '(FLAGS INTERNALDATE RFC822.SIZE RFC822.HEADER RFC822.TEXT)'))
+            run('uid', ('STORE', uid[-1], 'FLAGS', '(\Deleted)'))
+            run('expunge', ())
+
+        if 'IDLE' in M.capabilities:
+            run('idle', (2,), cb=False)
+            run('idle', (99,))          # Asynchronous, to test interruption of 'idle' by 'noop'
+            time.sleep(1)
+            run('noop', (), cb=False)
+
+            run('append', (None, None, None, test_mesg), cb=False)
+            num = run('search', (None, 'ALL'), cb=False)[0].split()[0]
+            dat = run('fetch', (num, '(FLAGS INTERNALDATE RFC822)'), cb=False)
+            M._mesg('fetch %s => %s' % (num, repr(dat)))
+            run('idle', (2,))
+            run('store', (num, '-FLAGS', '(\Seen)'), cb=False),
+            dat = run('fetch', (num, '(FLAGS INTERNALDATE RFC822)'), cb=False)
+            M._mesg('fetch %s => %s' % (num, repr(dat)))
+            run('uid', ('STORE', num, 'FLAGS', '(\Deleted)'))
+            run('expunge', ())
+            if idle_intr:
+                M._mesg('HIT CTRL-C to interrupt IDLE')
+                try:
+                    run('idle', (99,), cb=False) # Synchronous, to test interruption of 'idle' by INTR
+                except KeyboardInterrupt:
+                    M._mesg('Thanks!')
+                    M._mesg('')
+                    raise
+        elif idle_intr:
+            M._mesg('chosen server does not report IDLE capability')
+
+        run('logout', (), cb=False)
+
+        if debug:
+            M._mesg('')
+            M._print_log()
+            M._mesg('')
+            M._mesg('unused untagged responses in order, most recent last:')
+            for typ,dat in M.pop_untagged_responses(): M._mesg('\t%s %s' % (typ, dat))
+
+        print('All tests OK.')
+
+    except:
+        if not idle_intr or M is None or not 'IDLE' in M.capabilities:
+            print('Tests failed.')
+
+            if not debug:
+                print('''
+If you would like to see debugging output,
+try: %s -d5
+''' % sys.argv[0])
+
+            raise