add ydb deps

1 files changed, 1649 insertions, 0 deletions

diff --git a/contrib/tools/python3/src/Lib/imaplib.py b/contrib/tools/python3/src/Lib/imaplib.py
new file mode 100644
index 0000000000..fa4c0f8f62
--- /dev/null
+++ b/contrib/tools/python3/src/Lib/imaplib.py
@@ -0,0 +1,1649 @@
+"""IMAP4 client.
+
+Based on RFC 2060.
+
+Public class:           IMAP4
+Public variable:        Debug
+Public functions:       Internaldate2tuple
+                        Int2AP
+                        ParseFlags
+                        Time2Internaldate
+"""
+
+# Author: Piers Lauder <piers@cs.su.oz.au> December 1997.
+#
+# 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.
+# GET/SETANNOTATION contributed by Tomas Lindroos <skitta@abo.fi> June 2005.
+
+__version__ = "2.58"
+
+import binascii, errno, random, re, socket, subprocess, sys, time, calendar
+from datetime import datetime, timezone, timedelta
+from io import DEFAULT_BUFFER_SIZE
+
+try:
+    import ssl
+    HAVE_SSL = True
+except ImportError:
+    HAVE_SSL = False
+
+__all__ = ["IMAP4", "IMAP4_stream", "Internaldate2tuple",
+           "Int2AP", "ParseFlags", "Time2Internaldate"]
+
+#       Globals
+
+CRLF = b'\r\n'
+Debug = 0
+IMAP4_PORT = 143
+IMAP4_SSL_PORT = 993
+AllowedVersions = ('IMAP4REV1', 'IMAP4')        # Most recent first
+
+# Maximal line length when calling readline(). This is to prevent
+# reading arbitrary length lines. RFC 3501 and 2060 (IMAP 4rev1)
+# don't specify a line length. RFC 2683 suggests limiting client
+# command lines to 1000 octets and that servers should be prepared
+# to accept command lines up to 8000 octets, so we used to use 10K here.
+# In the modern world (eg: gmail) the response to, for example, a
+# search command can be quite large, so we now use 1M.
+_MAXLINE = 1000000
+
+
+#       Commands
+
+Commands = {
+        # name            valid states
+        'APPEND':       ('AUTH', 'SELECTED'),
+        'AUTHENTICATE': ('NONAUTH',),
+        'CAPABILITY':   ('NONAUTH', 'AUTH', 'SELECTED', 'LOGOUT'),
+        'CHECK':        ('SELECTED',),
+        'CLOSE':        ('SELECTED',),
+        'COPY':         ('SELECTED',),
+        'CREATE':       ('AUTH', 'SELECTED'),
+        'DELETE':       ('AUTH', 'SELECTED'),
+        'DELETEACL':    ('AUTH', 'SELECTED'),
+        'ENABLE':       ('AUTH', ),
+        'EXAMINE':      ('AUTH', 'SELECTED'),
+        'EXPUNGE':      ('SELECTED',),
+        'FETCH':        ('SELECTED',),
+        'GETACL':       ('AUTH', 'SELECTED'),
+        'GETANNOTATION':('AUTH', 'SELECTED'),
+        'GETQUOTA':     ('AUTH', 'SELECTED'),
+        'GETQUOTAROOT': ('AUTH', 'SELECTED'),
+        'MYRIGHTS':     ('AUTH', 'SELECTED'),
+        'LIST':         ('AUTH', 'SELECTED'),
+        'LOGIN':        ('NONAUTH',),
+        'LOGOUT':       ('NONAUTH', 'AUTH', 'SELECTED', 'LOGOUT'),
+        'LSUB':         ('AUTH', 'SELECTED'),
+        'MOVE':         ('SELECTED',),
+        'NAMESPACE':    ('AUTH', 'SELECTED'),
+        'NOOP':         ('NONAUTH', 'AUTH', 'SELECTED', 'LOGOUT'),
+        'PARTIAL':      ('SELECTED',),                                  # NB: obsolete
+        'PROXYAUTH':    ('AUTH',),
+        'RENAME':       ('AUTH', 'SELECTED'),
+        'SEARCH':       ('SELECTED',),
+        'SELECT':       ('AUTH', 'SELECTED'),
+        'SETACL':       ('AUTH', 'SELECTED'),
+        'SETANNOTATION':('AUTH', 'SELECTED'),
+        'SETQUOTA':     ('AUTH', 'SELECTED'),
+        'SORT':         ('SELECTED',),
+        'STARTTLS':     ('NONAUTH',),
+        'STATUS':       ('AUTH', 'SELECTED'),
+        'STORE':        ('SELECTED',),
+        'SUBSCRIBE':    ('AUTH', 'SELECTED'),
+        'THREAD':       ('SELECTED',),
+        'UID':          ('SELECTED',),
+        'UNSUBSCRIBE':  ('AUTH', 'SELECTED'),
+        'UNSELECT':     ('SELECTED',),
+        }
+
+#       Patterns to match server responses
+
+Continuation = re.compile(br'\+( (?P<data>.*))?')
+Flags = re.compile(br'.*FLAGS \((?P<flags>[^\)]*)\)')
+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'"')
+# Literal is no longer used; kept for backward compatibility.
+Literal = re.compile(br'.*{(?P<size>\d+)}$', re.ASCII)
+MapCRLF = re.compile(br'\r\n|\r|\n')
+# We no longer exclude the ']' character from the data portion of the response
+# code, even though it violates the RFC.  Popular IMAP servers such as Gmail
+# allow flags with ']', and there are programs (including imaplib!) that can
+# produce them.  The problem with this is if the 'text' portion of the response
+# includes a ']' we'll parse the response wrong (which is the point of the RFC
+# restriction).  However, that seems less likely to be a problem in practice
+# than being unable to correctly parse flags that include ']' chars, which
+# was reported as a real-world problem in issue #21815.
+Response_code = re.compile(br'\[(?P<type>[A-Z-]+)( (?P<data>.*))?\]')
+Untagged_response = re.compile(br'\* (?P<type>[A-Z-]+)( (?P<data>.*))?')
+# Untagged_status is no longer used; kept for backward compatibility
+Untagged_status = re.compile(
+    br'\* (?P<data>\d+) (?P<type>[A-Z-]+)( (?P<data2>.*))?', re.ASCII)
+# We compile these in _mode_xxx.
+_Literal = br'.*{(?P<size>\d+)}$'
+_Untagged_status = br'\* (?P<data>\d+) (?P<type>[A-Z-]+)( (?P<data2>.*))?'
+
+
+
+class IMAP4:
+
+    r"""IMAP4 client class.
+
+    Instantiate with: IMAP4([host[, port[, timeout=None]]])
+
+            host - host's name (default: localhost);
+            port - port number (default: standard IMAP4 port).
+            timeout - socket timeout (default: None)
+                      If timeout is not given or is None,
+                      the global default socket timeout is used
+
+    All IMAP4rev1 commands are supported by methods of the same
+    name (in lowercase).
+
+    All arguments to commands are converted to strings, except for
+    AUTHENTICATE, and the last argument to APPEND which is passed as
+    an IMAP4 literal.  If necessary (the string contains any
+    non-printing characters or white-space and isn't enclosed with
+    either parentheses or double quotes) each string is quoted.
+    However, the 'password' argument to the LOGIN command is always
+    quoted.  If you want to avoid having an argument string quoted
+    (eg: the 'flags' argument to STORE) then enclose the string in
+    parentheses (eg: "(\Deleted)").
+
+    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.
+
+    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.
+    """
+
+    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
+
+    def __init__(self, host='', port=IMAP4_PORT, timeout=None):
+        self.debug = Debug
+        self.state = 'LOGOUT'
+        self.literal = None             # A literal argument to a command
+        self.tagged_commands = {}       # Tagged commands awaiting response
+        self.untagged_responses = {}    # {typ: [data, ...], ...}
+        self.continuation_response = '' # Last continuation response
+        self.is_readonly = False        # READ-ONLY desired state
+        self.tagnum = 0
+        self._tls_established = False
+        self._mode_ascii()
+
+        # Open socket to server.
+
+        self.open(host, port, timeout)
+
+        try:
+            self._connect()
+        except Exception:
+            try:
+                self.shutdown()
+            except OSError:
+                pass
+            raise
+
+    def _mode_ascii(self):
+        self.utf8_enabled = False
+        self._encoding = 'ascii'
+        self.Literal = re.compile(_Literal, re.ASCII)
+        self.Untagged_status = re.compile(_Untagged_status, re.ASCII)
+
+
+    def _mode_utf8(self):
+        self.utf8_enabled = True
+        self._encoding = 'utf-8'
+        self.Literal = re.compile(_Literal)
+        self.Untagged_status = re.compile(_Untagged_status)
+
+
+    def _connect(self):
+        # Create unique tag for this session,
+        # and compile tagged response matcher.
+
+        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)
+
+        # Get server welcome message,
+        # request and store CAPABILITY response.
+
+        if __debug__:
+            self._cmd_log_len = 10
+            self._cmd_log_idx = 0
+            self._cmd_log = {}           # Last `_cmd_log_len' interactions
+            if self.debug >= 1:
+                self._mesg('imaplib version %s' % __version__)
+                self._mesg('new IMAP4 connection, tag=%s' % self.tagpre)
+
+        self.welcome = self._get_response()
+        if 'PREAUTH' in self.untagged_responses:
+            self.state = 'AUTH'
+        elif 'OK' in self.untagged_responses:
+            self.state = 'NONAUTH'
+        else:
+            raise self.error(self.welcome)
+
+        self._get_capabilities()
+        if __debug__:
+            if self.debug >= 3:
+                self._mesg('CAPABILITIES: %r' % (self.capabilities,))
+
+        for version in AllowedVersions:
+            if not version in self.capabilities:
+                continue
+            self.PROTOCOL_VERSION = version
+            return
+
+        raise self.error('server not IMAP4 compliant')
+
+
+    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):
+        if self.state == "LOGOUT":
+            return
+
+        try:
+            self.logout()
+        except OSError:
+            pass
+
+
+    #       Overridable methods
+
+
+    def _create_socket(self, timeout):
+        # Default value of IMAP4.host is '', but socket.getaddrinfo()
+        # (which is used by socket.create_connection()) expects None
+        # as a default value for host.
+        if timeout is not None and not timeout:
+            raise ValueError('Non-blocking socket (timeout=0) is not supported')
+        host = None if not self.host else self.host
+        sys.audit("imaplib.open", self, self.host, self.port)
+        address = (host, self.port)
+        if timeout is not None:
+            return socket.create_connection(address, timeout)
+        return socket.create_connection(address)
+
+    def open(self, host='', port=IMAP4_PORT, timeout=None):
+        """Setup connection to remote server on "host:port"
+            (default: localhost:standard IMAP4 port).
+        This connection will be used by the routines:
+            read, readline, send, shutdown.
+        """
+        self.host = host
+        self.port = port
+        self.sock = self._create_socket(timeout)
+        self.file = self.sock.makefile('rb')
+
+
+    def read(self, size):
+        """Read 'size' bytes from remote."""
+        return self.file.read(size)
+
+
+    def readline(self):
+        """Read line from remote."""
+        line = self.file.readline(_MAXLINE + 1)
+        if len(line) > _MAXLINE:
+            raise self.error("got more than %d bytes" % _MAXLINE)
+        return line
+
+
+    def send(self, data):
+        """Send data to remote."""
+        sys.audit("imaplib.send", self, data)
+        self.sock.sendall(data)
+
+
+    def shutdown(self):
+        """Close I/O established in "open"."""
+        self.file.close()
+        try:
+            self.sock.shutdown(socket.SHUT_RDWR)
+        except OSError as exc:
+            # The server might already have closed the connection.
+            # On Windows, this may result in WSAEINVAL (error 10022):
+            # An invalid operation was attempted.
+            if (exc.errno != errno.ENOTCONN
+               and getattr(exc, 'winerror', 0) != 10022):
+                raise
+        finally:
+            self.sock.close()
+
+
+    def socket(self):
+        """Return socket instance used to connect to IMAP4 server.
+
+        socket = <instance>.socket()
+        """
+        return self.sock
+
+
+
+    #       Utility methods
+
+
+    def recent(self):
+        """Return most recent 'RECENT' responses if any exist,
+        else prompt server for an update using the 'NOOP' command.
+
+        (typ, [data]) = <instance>.recent()
+
+        'data' is None if no new messages,
+        else list of RECENT responses, most recent last.
+        """
+        name = 'RECENT'
+        typ, dat = self._untagged_response('OK', [None], name)
+        if dat[-1]:
+            return typ, dat
+        typ, dat = self.noop()  # Prod server for response
+        return self._untagged_response(typ, dat, name)
+
+
+    def response(self, code):
+        """Return data for response 'code' if received, or None.
+
+        Old value for response 'code' is cleared.
+
+        (code, [data]) = <instance>.response(code)
+        """
+        return self._untagged_response(code, [None], code.upper())
+
+
+
+    #       IMAP4 commands
+
+
+    def append(self, mailbox, flags, date_time, message):
+        """Append message to named mailbox.
+
+        (typ, [data]) = <instance>.append(mailbox, flags, date_time, message)
+
+                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
+        literal = MapCRLF.sub(CRLF, message)
+        if self.utf8_enabled:
+            literal = b'UTF8 (' + literal + b')'
+        self.literal = literal
+        return self._simple_command(name, mailbox, flags, date_time)
+
+
+    def authenticate(self, 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 it is passed will be a bytes.  It should return bytes
+        data that will be base64 encoded and sent to the server.  It should
+        return None if the client abort response '*' should be sent instead.
+        """
+        mech = mechanism.upper()
+        # XXX: shouldn't this code be removed, not commented out?
+        #cap = 'AUTH=%s' % mech
+        #if not cap in self.capabilities:       # Let the server decide!
+        #    raise self.error("Server doesn't allow %s authentication." % mech)
+        self.literal = _Authenticator(authobject).process
+        typ, dat = self._simple_command('AUTHENTICATE', mech)
+        if typ != 'OK':
+            raise self.error(dat[-1].decode('utf-8', 'replace'))
+        self.state = 'AUTH'
+        return typ, dat
+
+
+    def capability(self):
+        """(typ, [data]) = <instance>.capability()
+        Fetch capabilities list from server."""
+
+        name = 'CAPABILITY'
+        typ, dat = self._simple_command(name)
+        return self._untagged_response(typ, dat, name)
+
+
+    def check(self):
+        """Checkpoint mailbox on server.
+
+        (typ, [data]) = <instance>.check()
+        """
+        return self._simple_command('CHECK')
+
+
+    def close(self):
+        """Close currently selected mailbox.
+
+        Deleted messages are removed from writable mailbox.
+        This is the recommended command before 'LOGOUT'.
+
+        (typ, [data]) = <instance>.close()
+        """
+        try:
+            typ, dat = self._simple_command('CLOSE')
+        finally:
+            self.state = 'AUTH'
+        return typ, dat
+
+
+    def copy(self, message_set, new_mailbox):
+        """Copy 'message_set' messages onto end of 'new_mailbox'.
+
+        (typ, [data]) = <instance>.copy(message_set, new_mailbox)
+        """
+        return self._simple_command('COPY', message_set, new_mailbox)
+
+
+    def create(self, mailbox):
+        """Create new mailbox.
+
+        (typ, [data]) = <instance>.create(mailbox)
+        """
+        return self._simple_command('CREATE', mailbox)
+
+
+    def delete(self, mailbox):
+        """Delete old mailbox.
+
+        (typ, [data]) = <instance>.delete(mailbox)
+        """
+        return self._simple_command('DELETE', mailbox)
+
+    def deleteacl(self, mailbox, who):
+        """Delete the ACLs (remove any rights) set for who on mailbox.
+
+        (typ, [data]) = <instance>.deleteacl(mailbox, who)
+        """
+        return self._simple_command('DELETEACL', mailbox, who)
+
+    def enable(self, capability):
+        """Send an RFC5161 enable string to the server.
+
+        (typ, [data]) = <instance>.enable(capability)
+        """
+        if 'ENABLE' not in self.capabilities:
+            raise IMAP4.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 expunge(self):
+        """Permanently remove deleted items from selected mailbox.
+
+        Generates 'EXPUNGE' response for each deleted message.
+
+        (typ, [data]) = <instance>.expunge()
+
+        'data' is list of 'EXPUNGE'd message numbers in order received.
+        """
+        name = 'EXPUNGE'
+        typ, dat = self._simple_command(name)
+        return self._untagged_response(typ, dat, name)
+
+
+    def fetch(self, message_set, message_parts):
+        """Fetch (parts of) messages.
+
+        (typ, [data, ...]) = <instance>.fetch(message_set, message_parts)
+
+        '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.
+        """
+        name = 'FETCH'
+        typ, dat = self._simple_command(name, message_set, message_parts)
+        return self._untagged_response(typ, dat, name)
+
+
+    def getacl(self, mailbox):
+        """Get the ACLs for a mailbox.
+
+        (typ, [data]) = <instance>.getacl(mailbox)
+        """
+        typ, dat = self._simple_command('GETACL', mailbox)
+        return self._untagged_response(typ, dat, 'ACL')
+
+
+    def getannotation(self, mailbox, entry, attribute):
+        """(typ, [data]) = <instance>.getannotation(mailbox, entry, attribute)
+        Retrieve ANNOTATIONs."""
+
+        typ, dat = self._simple_command('GETANNOTATION', mailbox, entry, attribute)
+        return self._untagged_response(typ, dat, 'ANNOTATION')
+
+
+    def getquota(self, root):
+        """Get the quota root's resource usage and limits.
+
+        Part of the IMAP4 QUOTA extension defined in rfc2087.
+
+        (typ, [data]) = <instance>.getquota(root)
+        """
+        typ, dat = self._simple_command('GETQUOTA', root)
+        return self._untagged_response(typ, dat, 'QUOTA')
+
+
+    def getquotaroot(self, mailbox):
+        """Get the list of quota roots for the named mailbox.
+
+        (typ, [[QUOTAROOT responses...], [QUOTA responses]]) = <instance>.getquotaroot(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 typ, [quotaroot, quota]
+
+
+    def list(self, directory='""', pattern='*'):
+        """List mailbox names in directory matching pattern.
+
+        (typ, [data]) = <instance>.list(directory='""', pattern='*')
+
+        'data' is list of LIST responses.
+        """
+        name = 'LIST'
+        typ, dat = self._simple_command(name, directory, pattern)
+        return self._untagged_response(typ, dat, name)
+
+
+    def login(self, user, password):
+        """Identify client using plaintext password.
+
+        (typ, [data]) = <instance>.login(user, password)
+
+        NB: 'password' will be quoted.
+        """
+        typ, dat = self._simple_command('LOGIN', user, self._quote(password))
+        if typ != 'OK':
+            raise self.error(dat[-1])
+        self.state = 'AUTH'
+        return typ, dat
+
+
+    def login_cram_md5(self, user, password):
+        """ Force use of CRAM-MD5 authentication.
+
+        (typ, [data]) = <instance>.login_cram_md5(user, password)
+        """
+        self.user, self.password = user, password
+        return self.authenticate('CRAM-MD5', self._CRAM_MD5_AUTH)
+
+
+    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):
+        """Shutdown connection to server.
+
+        (typ, [data]) = <instance>.logout()
+
+        Returns server 'BYE' response.
+        """
+        self.state = 'LOGOUT'
+        typ, dat = self._simple_command('LOGOUT')
+        self.shutdown()
+        return typ, dat
+
+
+    def lsub(self, directory='""', pattern='*'):
+        """List 'subscribed' mailbox names in directory matching pattern.
+
+        (typ, [data, ...]) = <instance>.lsub(directory='""', pattern='*')
+
+        'data' are tuples of message part envelope and data.
+        """
+        name = 'LSUB'
+        typ, dat = self._simple_command(name, directory, pattern)
+        return self._untagged_response(typ, dat, name)
+
+    def myrights(self, mailbox):
+        """Show my ACLs for a mailbox (i.e. the rights that I have on mailbox).
+
+        (typ, [data]) = <instance>.myrights(mailbox)
+        """
+        typ,dat = self._simple_command('MYRIGHTS', mailbox)
+        return self._untagged_response(typ, dat, 'MYRIGHTS')
+
+    def namespace(self):
+        """ Returns IMAP namespaces ala rfc2342
+
+        (typ, [data, ...]) = <instance>.namespace()
+        """
+        name = 'NAMESPACE'
+        typ, dat = self._simple_command(name)
+        return self._untagged_response(typ, dat, name)
+
+
+    def noop(self):
+        """Send NOOP command.
+
+        (typ, [data]) = <instance>.noop()
+        """
+        if __debug__:
+            if self.debug >= 3:
+                self._dump_ur(self.untagged_responses)
+        return self._simple_command('NOOP')
+
+
+    def partial(self, message_num, message_part, start, length):
+        """Fetch truncated part of a message.
+
+        (typ, [data, ...]) = <instance>.partial(message_num, message_part, start, length)
+
+        'data' is tuple of message part envelope and data.
+        """
+        name = 'PARTIAL'
+        typ, dat = self._simple_command(name, message_num, message_part, start, length)
+        return self._untagged_response(typ, dat, 'FETCH')
+
+
+    def proxyauth(self, user):
+        """Assume authentication as "user".
+
+        Allows an authorised administrator to proxy into any user's
+        mailbox.
+
+        (typ, [data]) = <instance>.proxyauth(user)
+        """
+
+        name = 'PROXYAUTH'
+        return self._simple_command('PROXYAUTH', user)
+
+
+    def rename(self, oldmailbox, newmailbox):
+        """Rename old mailbox name to new.
+
+        (typ, [data]) = <instance>.rename(oldmailbox, newmailbox)
+        """
+        return self._simple_command('RENAME', oldmailbox, newmailbox)
+
+
+    def search(self, charset, *criteria):
+        """Search mailbox for matching messages.
+
+        (typ, [data]) = <instance>.search(charset, criterion, ...)
+
+        'data' is space separated list of matching message numbers.
+        If UTF8 is enabled, charset MUST be None.
+        """
+        name = 'SEARCH'
+        if charset:
+            if self.utf8_enabled:
+                raise IMAP4.error("Non-None charset not valid in UTF8 mode")
+            typ, dat = self._simple_command(name, 'CHARSET', charset, *criteria)
+        else:
+            typ, dat = self._simple_command(name, *criteria)
+        return self._untagged_response(typ, dat, name)
+
+
+    def select(self, mailbox='INBOX', readonly=False):
+        """Select a mailbox.
+
+        Flush all untagged responses.
+
+        (typ, [data]) = <instance>.select(mailbox='INBOX', readonly=False)
+
+        'data' is count of messages in mailbox ('EXISTS' response).
+
+        Mandated responses are ('FLAGS', 'EXISTS', 'RECENT', 'UIDVALIDITY'), so
+        other responses should be obtained via <instance>.response('FLAGS') etc.
+        """
+        self.untagged_responses = {}    # Flush old responses.
+        self.is_readonly = readonly
+        if readonly:
+            name = 'EXAMINE'
+        else:
+            name = 'SELECT'
+        typ, dat = self._simple_command(name, mailbox)
+        if typ != 'OK':
+            self.state = 'AUTH'     # Might have been 'SELECTED'
+            return typ, dat
+        self.state = 'SELECTED'
+        if 'READ-ONLY' in self.untagged_responses \
+                and not readonly:
+            if __debug__:
+                if self.debug >= 1:
+                    self._dump_ur(self.untagged_responses)
+            raise self.readonly('%s is not writable' % mailbox)
+        return typ, self.untagged_responses.get('EXISTS', [None])
+
+
+    def setacl(self, mailbox, who, what):
+        """Set a mailbox acl.
+
+        (typ, [data]) = <instance>.setacl(mailbox, who, what)
+        """
+        return self._simple_command('SETACL', mailbox, who, what)
+
+
+    def setannotation(self, *args):
+        """(typ, [data]) = <instance>.setannotation(mailbox[, entry, attribute]+)
+        Set ANNOTATIONs."""
+
+        typ, dat = self._simple_command('SETANNOTATION', *args)
+        return self._untagged_response(typ, dat, 'ANNOTATION')
+
+
+    def setquota(self, root, limits):
+        """Set the quota root's resource limits.
+
+        (typ, [data]) = <instance>.setquota(root, limits)
+        """
+        typ, dat = self._simple_command('SETQUOTA', root, limits)
+        return self._untagged_response(typ, dat, 'QUOTA')
+
+
+    def sort(self, sort_criteria, charset, *search_criteria):
+        """IMAP4rev1 extension SORT command.
+
+        (typ, [data]) = <instance>.sort(sort_criteria, charset, search_criteria, ...)
+        """
+        name = 'SORT'
+        #if not name in self.capabilities:      # Let the server decide!
+        #       raise self.error('unimplemented extension command: %s' % name)
+        if (sort_criteria[0],sort_criteria[-1]) != ('(',')'):
+            sort_criteria = '(%s)' % sort_criteria
+        typ, dat = self._simple_command(name, sort_criteria, charset, *search_criteria)
+        return self._untagged_response(typ, dat, name)
+
+
+    def starttls(self, ssl_context=None):
+        name = 'STARTTLS'
+        if not HAVE_SSL:
+            raise self.error('SSL support missing')
+        if self._tls_established:
+            raise self.abort('TLS session already established')
+        if name not in self.capabilities:
+            raise self.abort('TLS not supported by server')
+        # Generate a default SSL context if none was passed.
+        if ssl_context is None:
+            ssl_context = ssl._create_stdlib_context()
+        typ, dat = self._simple_command(name)
+        if typ == 'OK':
+            self.sock = ssl_context.wrap_socket(self.sock,
+                                                server_hostname=self.host)
+            self.file = self.sock.makefile('rb')
+            self._tls_established = True
+            self._get_capabilities()
+        else:
+            raise self.error("Couldn't establish TLS session")
+        return self._untagged_response(typ, dat, name)
+
+
+    def status(self, mailbox, names):
+        """Request named status conditions for mailbox.
+
+        (typ, [data]) = <instance>.status(mailbox, names)
+        """
+        name = 'STATUS'
+        #if self.PROTOCOL_VERSION == 'IMAP4':   # Let the server decide!
+        #    raise self.error('%s unimplemented in IMAP4 (obtain IMAP4rev1 server, or re-code)' % name)
+        typ, dat = self._simple_command(name, mailbox, names)
+        return self._untagged_response(typ, dat, name)
+
+
+    def store(self, message_set, command, flags):
+        """Alters flag dispositions for messages in mailbox.
+
+        (typ, [data]) = <instance>.store(message_set, command, flags)
+        """
+        if (flags[0],flags[-1]) != ('(',')'):
+            flags = '(%s)' % flags  # Avoid quoting the flags
+        typ, dat = self._simple_command('STORE', message_set, command, flags)
+        return self._untagged_response(typ, dat, 'FETCH')
+
+
+    def subscribe(self, mailbox):
+        """Subscribe to new mailbox.
+
+        (typ, [data]) = <instance>.subscribe(mailbox)
+        """
+        return self._simple_command('SUBSCRIBE', mailbox)
+
+
+    def thread(self, threading_algorithm, charset, *search_criteria):
+        """IMAPrev1 extension THREAD command.
+
+        (type, [data]) = <instance>.thread(threading_algorithm, charset, search_criteria, ...)
+        """
+        name = 'THREAD'
+        typ, dat = self._simple_command(name, threading_algorithm, charset, *search_criteria)
+        return self._untagged_response(typ, dat, name)
+
+
+    def uid(self, command, *args):
+        """Execute "command arg ..." with messages identified by UID,
+                rather than message number.
+
+        (typ, [data]) = <instance>.uid(command, arg1, arg2, ...)
+
+        Returns response appropriate to 'command'.
+        """
+        command = command.upper()
+        if not command in Commands:
+            raise self.error("Unknown IMAP4 UID command: %s" % command)
+        if self.state not in Commands[command]:
+            raise self.error("command %s illegal in state %s, "
+                             "only allowed in states %s" %
+                             (command, self.state,
+                              ', '.join(Commands[command])))
+        name = 'UID'
+        typ, dat = self._simple_command(name, command, *args)
+        if command in ('SEARCH', 'SORT', 'THREAD'):
+            name = command
+        else:
+            name = 'FETCH'
+        return self._untagged_response(typ, dat, name)
+
+
+    def unsubscribe(self, mailbox):
+        """Unsubscribe from old mailbox.
+
+        (typ, [data]) = <instance>.unsubscribe(mailbox)
+        """
+        return self._simple_command('UNSUBSCRIBE', mailbox)
+
+
+    def unselect(self):
+        """Free server's resources associated with the selected mailbox
+        and returns the server to the authenticated state.
+        This command performs the same actions as CLOSE, except
+        that no messages are permanently removed from the currently
+        selected mailbox.
+
+        (typ, [data]) = <instance>.unselect()
+        """
+        try:
+            typ, data = self._simple_command('UNSELECT')
+        finally:
+            self.state = 'AUTH'
+        return typ, data
+
+
+    def xatom(self, name, *args):
+        """Allow simple extension commands
+                notified by server in CAPABILITY response.
+
+        Assumes command is legal in current state.
+
+        (typ, [data]) = <instance>.xatom(name, arg, ...)
+
+        Returns response appropriate to extension command `name'.
+        """
+        name = name.upper()
+        #if not name in self.capabilities:      # Let the server decide!
+        #    raise self.error('unknown extension command: %s' % name)
+        if not name in Commands:
+            Commands[name] = (self.state,)
+        return self._simple_command(name, *args)
+
+
+
+    #       Private methods
+
+
+    def _append_untagged(self, typ, dat):
+        if dat is None:
+            dat = b''
+        ur = self.untagged_responses
+        if __debug__:
+            if self.debug >= 5:
+                self._mesg('untagged_responses[%s] %s += ["%r"]' %
+                        (typ, len(ur.get(typ,'')), dat))
+        if typ in ur:
+            ur[typ].append(dat)
+        else:
+            ur[typ] = [dat]
+
+
+    def _check_bye(self):
+        bye = self.untagged_responses.get('BYE')
+        if bye:
+            raise self.abort(bye[-1].decode(self._encoding, 'replace'))
+
+
+    def _command(self, name, *args):
+
+        if self.state not in Commands[name]:
+            self.literal = None
+            raise self.error("command %s illegal in state %s, "
+                             "only allowed in states %s" %
+                             (name, self.state,
+                              ', '.join(Commands[name])))
+
+        for typ in ('OK', 'NO', 'BAD'):
+            if typ in self.untagged_responses:
+                del self.untagged_responses[typ]
+
+        if 'READ-ONLY' in self.untagged_responses \
+        and not self.is_readonly:
+            raise self.readonly('mailbox status changed to READ-ONLY')
+
+        tag = self._new_tag()
+        name = bytes(name, self._encoding)
+        data = 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__:
+            if self.debug >= 4:
+                self._mesg('> %r' % data)
+            else:
+                self._log('> %r' % data)
+
+        try:
+            self.send(data + CRLF)
+        except OSError as val:
+            raise self.abort('socket error: %s' % val)
+
+        if literal is None:
+            return tag
+
+        while 1:
+            # Wait for continuation response
+
+            while self._get_response():
+                if self.tagged_commands[tag]:   # BAD/NO?
+                    return tag
+
+            # Send literal
+
+            if literator:
+                literal = literator(self.continuation_response)
+
+            if __debug__:
+                if self.debug >= 4:
+                    self._mesg('write literal size %s' % len(literal))
+
+            try:
+                self.send(literal)
+                self.send(CRLF)
+            except OSError as val:
+                raise self.abort('socket error: %s' % val)
+
+            if not literator:
+                break
+
+        return tag
+
+
+    def _command_complete(self, name, tag):
+        logout = (name == 'LOGOUT')
+        # BYE is expected after LOGOUT
+        if not logout:
+            self._check_bye()
+        try:
+            typ, data = self._get_tagged_response(tag, expect_bye=logout)
+        except self.abort as val:
+            raise self.abort('command: %s => %s' % (name, val))
+        except self.error as val:
+            raise self.error('command: %s => %s' % (name, val))
+        if not logout:
+            self._check_bye()
+        if typ == 'BAD':
+            raise self.error('%s command error: %s %s' % (name, typ, data))
+        return typ, data
+
+
+    def _get_capabilities(self):
+        typ, dat = self.capability()
+        if dat == [None]:
+            raise self.error('no CAPABILITY response from server')
+        dat = str(dat[-1], self._encoding)
+        dat = dat.upper()
+        self.capabilities = tuple(dat.split())
+
+
+    def _get_response(self):
+
+        # Read response and store.
+        #
+        # Returns None for continuation responses,
+        # otherwise first response line received.
+
+        resp = self._get_line()
+
+        # Command completion response?
+
+        if self._match(self.tagre, resp):
+            tag = self.mo.group('tag')
+            if not tag in self.tagged_commands:
+                raise self.abort('unexpected tagged response: %r' % resp)
+
+            typ = self.mo.group('type')
+            typ = str(typ, self._encoding)
+            dat = self.mo.group('data')
+            self.tagged_commands[tag] = (typ, [dat])
+        else:
+            dat2 = None
+
+            # '*' (untagged) responses?
+
+            if not self._match(Untagged_response, resp):
+                if self._match(self.Untagged_status, resp):
+                    dat2 = self.mo.group('data2')
+
+            if self.mo is None:
+                # Only other possibility is '+' (continuation) response...
+
+                if self._match(Continuation, resp):
+                    self.continuation_response = self.mo.group('data')
+                    return None     # NB: indicates continuation
+
+                raise self.abort("unexpected response: %r" % resp)
+
+            typ = self.mo.group('type')
+            typ = str(typ, self._encoding)
+            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?
+
+            while self._match(self.Literal, dat):
+
+                # Read literal direct from connection.
+
+                size = int(self.mo.group('size'))
+                if __debug__:
+                    if self.debug >= 4:
+                        self._mesg('read literal size %s' % size)
+                data = self.read(size)
+
+                # Store response with literal as tuple
+
+                self._append_untagged(typ, (dat, data))
+
+                # Read trailer - possibly containing another literal
+
+                dat = self._get_line()
+
+            self._append_untagged(typ, dat)
+
+        # Bracketed response information?
+
+        if typ in ('OK', 'NO', 'BAD') and self._match(Response_code, dat):
+            typ = self.mo.group('type')
+            typ = str(typ, self._encoding)
+            self._append_untagged(typ, self.mo.group('data'))
+
+        if __debug__:
+            if self.debug >= 1 and typ in ('NO', 'BAD', 'BYE'):
+                self._mesg('%s response: %r' % (typ, dat))
+
+        return resp
+
+
+    def _get_tagged_response(self, tag, expect_bye=False):
+
+        while 1:
+            result = self.tagged_commands[tag]
+            if result is not None:
+                del self.tagged_commands[tag]
+                return result
+
+            if expect_bye:
+                typ = 'BYE'
+                bye = self.untagged_responses.pop(typ, None)
+                if bye is not None:
+                    # Server replies to the "LOGOUT" command with "BYE"
+                    return (typ, bye)
+
+            # If we've seen a BYE at this point, the socket will be
+            # closed, so report the BYE now.
+            self._check_bye()
+
+            # Some have reported "unexpected response" exceptions.
+            # Note that ignoring them here causes loops.
+            # Instead, send me details of the unexpected response and
+            # I'll update the code in `_get_response()'.
+
+            try:
+                self._get_response()
+            except self.abort as val:
+                if __debug__:
+                    if self.debug >= 1:
+                        self.print_log()
+                raise
+
+
+    def _get_line(self):
+
+        line = self.readline()
+        if not line:
+            raise self.abort('socket error: EOF')
+
+        # Protocol mandates all lines terminated by CRLF
+        if not line.endswith(b'\r\n'):
+            raise self.abort('socket error: unterminated line: %r' % line)
+
+        line = line[:-2]
+        if __debug__:
+            if self.debug >= 4:
+                self._mesg('< %r' % line)
+            else:
+                self._log('< %r' % line)
+        return line
+
+
+    def _match(self, cre, s):
+
+        # Run compiled regular expression match method on 's'.
+        # Save result, return success.
+
+        self.mo = cre.match(s)
+        if __debug__:
+            if self.mo is not None and self.debug >= 5:
+                self._mesg("\tmatched %r => %r" % (cre.pattern, self.mo.groups()))
+        return self.mo is not None
+
+
+    def _new_tag(self):
+
+        tag = self.tagpre + bytes(str(self.tagnum), self._encoding)
+        self.tagnum = self.tagnum + 1
+        self.tagged_commands[tag] = None
+        return tag
+
+
+    def _quote(self, arg):
+
+        arg = arg.replace('\\', '\\\\')
+        arg = arg.replace('"', '\\"')
+
+        return '"' + arg + '"'
+
+
+    def _simple_command(self, name, *args):
+
+        return self._command_complete(name, self._command(name, *args))
+
+
+    def _untagged_response(self, typ, dat, name):
+        if typ == 'NO':
+            return typ, dat
+        if not name in self.untagged_responses:
+            return typ, [None]
+        data = self.untagged_responses.pop(name)
+        if __debug__:
+            if self.debug >= 5:
+                self._mesg('untagged_responses[%s] => %s' % (name, data))
+        return typ, data
+
+
+    if __debug__:
+
+        def _mesg(self, s, secs=None):
+            if secs is None:
+                secs = time.time()
+            tm = time.strftime('%M:%S', time.localtime(secs))
+            sys.stderr.write('  %s.%02d %s\n' % (tm, (secs*100)%100, s))
+            sys.stderr.flush()
+
+        def _dump_ur(self, untagged_resp_dict):
+            if not untagged_resp_dict:
+                return
+            items = (f'{key}: {value!r}'
+                    for key, value in untagged_resp_dict.items())
+            self._mesg('untagged responses dump:' + '\n\t\t'.join(items))
+
+        def _log(self, line):
+            # Keep log of last `_cmd_log_len' interactions for debugging.
+            self._cmd_log[self._cmd_log_idx] = (line, time.time())
+            self._cmd_log_idx += 1
+            if self._cmd_log_idx >= self._cmd_log_len:
+                self._cmd_log_idx = 0
+
+        def print_log(self):
+            self._mesg('last %d IMAP4 interactions:' % len(self._cmd_log))
+            i, n = self._cmd_log_idx, self._cmd_log_len
+            while n:
+                try:
+                    self._mesg(*self._cmd_log[i])
+                except:
+                    pass
+                i += 1
+                if i >= self._cmd_log_len:
+                    i = 0
+                n -= 1
+
+
+if HAVE_SSL:
+
+    class IMAP4_SSL(IMAP4):
+
+        """IMAP4 client class over SSL connection
+
+        Instantiate with: IMAP4_SSL([host[, port[, keyfile[, certfile[, ssl_context[, timeout=None]]]]]])
+
+                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);
+                ssl_context - a SSLContext object that contains your certificate chain
+                              and private key (default: None)
+                Note: if ssl_context is provided, then parameters keyfile or
+                certfile should not be set otherwise ValueError is raised.
+                timeout - socket timeout (default: None) If timeout is not given or is None,
+                          the global default socket timeout is used
+
+        for more documentation see the docstring of the parent class IMAP4.
+        """
+
+
+        def __init__(self, host='', port=IMAP4_SSL_PORT, keyfile=None,
+                     certfile=None, ssl_context=None, timeout=None):
+            if ssl_context is not None and keyfile is not None:
+                raise ValueError("ssl_context and keyfile arguments are mutually "
+                                 "exclusive")
+            if ssl_context is not None and certfile is not None:
+                raise ValueError("ssl_context and certfile arguments are mutually "
+                                 "exclusive")
+            if keyfile is not None or certfile is not None:
+                import warnings
+                warnings.warn("keyfile and certfile are deprecated, use a "
+                              "custom ssl_context instead", DeprecationWarning, 2)
+            self.keyfile = keyfile
+            self.certfile = certfile
+            if ssl_context is None:
+                ssl_context = ssl._create_stdlib_context(certfile=certfile,
+                                                         keyfile=keyfile)
+            self.ssl_context = ssl_context
+            IMAP4.__init__(self, host, port, timeout)
+
+        def _create_socket(self, timeout):
+            sock = IMAP4._create_socket(self, timeout)
+            return self.ssl_context.wrap_socket(sock,
+                                                server_hostname=self.host)
+
+        def open(self, host='', port=IMAP4_SSL_PORT, timeout=None):
+            """Setup connection to remote server on "host:port".
+                (default: localhost:standard IMAP4 SSL port).
+            This connection will be used by the routines:
+                read, readline, send, shutdown.
+            """
+            IMAP4.open(self, host, port, timeout)
+
+    __all__.append("IMAP4_SSL")
+
+
+class IMAP4_stream(IMAP4):
+
+    """IMAP4 client class over a stream
+
+    Instantiate with: IMAP4_stream(command)
+
+            "command" - a string that can be passed to subprocess.Popen()
+
+    for more documentation see the docstring of the parent class IMAP4.
+    """
+
+
+    def __init__(self, command):
+        self.command = command
+        IMAP4.__init__(self)
+
+
+    def open(self, host=None, port=None, timeout=None):
+        """Setup a stream connection.
+        This connection will be used by the routines:
+            read, readline, send, shutdown.
+        """
+        self.host = None        # For compatibility with parent class
+        self.port = None
+        self.sock = None
+        self.file = None
+        self.process = subprocess.Popen(self.command,
+            bufsize=DEFAULT_BUFFER_SIZE,
+            stdin=subprocess.PIPE, stdout=subprocess.PIPE,
+            shell=True, close_fds=True)
+        self.writefile = self.process.stdin
+        self.readfile = self.process.stdout
+
+    def read(self, size):
+        """Read 'size' bytes from remote."""
+        return self.readfile.read(size)
+
+
+    def readline(self):
+        """Read line from remote."""
+        return self.readfile.readline()
+
+
+    def send(self, data):
+        """Send data to remote."""
+        self.writefile.write(data)
+        self.writefile.flush()
+
+
+    def shutdown(self):
+        """Close I/O established in "open"."""
+        self.readfile.close()
+        self.writefile.close()
+        self.process.wait()
+
+
+
+class _Authenticator:
+
+    """Private class to provide en/decoding
+            for base64-based authentication conversation.
+    """
+
+    def __init__(self, mechinst):
+        self.mech = mechinst    # Callable object to provide/process data
+
+    def process(self, data):
+        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)
+
+Months = ' Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec'.split(' ')
+Mon2num = {s.encode():n+1 for n, s in enumerate(Months[1:])}
+
+def Internaldate2tuple(resp):
+    """Parse an IMAP4 INTERNALDATE string.
+
+    Return corresponding local time.  The return value is a
+    time.struct_time tuple 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)
+    utc = calendar.timegm(tt) - zone
+
+    return time.localtime(utc)
+
+
+
+def Int2AP(num):
+
+    """Convert integer to A-P string representation."""
+
+    val = b''; AP = b'ABCDEFGHIJKLMNOP'
+    num = int(abs(num))
+    while num:
+        num, mod = divmod(num, 16)
+        val = AP[mod:mod+1] + val
+    return val
+
+
+
+def ParseFlags(resp):
+
+    """Convert IMAP4 flags response to python tuple."""
+
+    mo = Flags.match(resp)
+    if not mo:
+        return ()
+
+    return tuple(mo.group('flags').split())
+
+
+def Time2Internaldate(date_time):
+
+    """Convert date_time to IMAP4 INTERNALDATE representation.
+
+    Return string in form: '"DD-Mmm-YYYY HH:MM:SS +HHMM"'.  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.
+    """
+    if isinstance(date_time, (int, float)):
+        dt = datetime.fromtimestamp(date_time,
+                                    timezone.utc).astimezone()
+    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(Months[dt.month])
+    return dt.strftime(fmt)
+
+
+
+if __name__ == '__main__':
+
+    # To test: invoke either as 'python imaplib.py [IMAP4_server_hostname]'
+    # or 'python imaplib.py -s "rsh IMAP4_server_hostname exec /etc/rimapd"'
+    # to test the IMAP4_stream class
+
+    import getopt, getpass
+
+    try:
+        optlist, args = getopt.getopt(sys.argv[1:], 'd:s:')
+    except getopt.error as val:
+        optlist, args = (), ()
+
+    stream_command = None
+    for opt,val in optlist:
+        if opt == '-d':
+            Debug = int(val)
+        elif opt == '-s':
+            stream_command = val
+            if not args: args = (stream_command,)
+
+    if not args: args = ('',)
+
+    host = args[0]
+
+    USER = getpass.getuser()
+    PASSWD = getpass.getpass("IMAP password for %s on %s: " % (USER, host or "localhost"))
+
+    test_mesg = 'From: %(user)s@localhost%(lf)sSubject: IMAP4 test%(lf)s%(lf)sdata...%(lf)s' % {'user':USER, 'lf':'\n'}
+    test_seq1 = (
+    ('login', (USER, PASSWD)),
+    ('create', ('/tmp/xxx 1',)),
+    ('rename', ('/tmp/xxx 1', '/tmp/yyy')),
+    ('CREATE', ('/tmp/yyz 2',)),
+    ('append', ('/tmp/yyz 2', None, None, test_mesg)),
+    ('list', ('/tmp', 'yy*')),
+    ('select', ('/tmp/yyz 2',)),
+    ('search', (None, 'SUBJECT', 'test')),
+    ('fetch', ('1', '(FLAGS INTERNALDATE RFC822)')),
+    ('store', ('1', 'FLAGS', r'(\Deleted)')),
+    ('namespace', ()),
+    ('expunge', ()),
+    ('recent', ()),
+    ('close', ()),
+    )
+
+    test_seq2 = (
+    ('select', ()),
+    ('response',('UIDVALIDITY',)),
+    ('uid', ('SEARCH', 'ALL')),
+    ('response', ('EXISTS',)),
+    ('append', (None, None, None, test_mesg)),
+    ('recent', ()),
+    ('logout', ()),
+    )
+
+    def run(cmd, args):
+        M._mesg('%s %s' % (cmd, args))
+        typ, dat = getattr(M, cmd)(*args)
+        M._mesg('%s => %s %s' % (cmd, typ, dat))
+        if typ == 'NO': raise dat[0]
+        return dat
+
+    try:
+        if stream_command:
+            M = IMAP4_stream(stream_command)
+        else:
+            M = IMAP4(host)
+        if M.state == 'AUTH':
+            test_seq1 = test_seq1[1:]   # Login not needed
+        M._mesg('PROTOCOL_VERSION = %s' % M.PROTOCOL_VERSION)
+        M._mesg('CAPABILITIES = %r' % (M.capabilities,))
+
+        for cmd,args in test_seq1:
+            run(cmd, args)
+
+        for ml in run('list', ('/tmp/', 'yy%')):
+            mo = re.match(r'.*"([^"]+)"$', ml)
+            if mo: path = mo.group(1)
+            else: path = ml.split()[-1]
+            run('delete', (path,))
+
+        for cmd,args in test_seq2:
+            dat = run(cmd, args)
+
+            if (cmd,args) != ('uid', ('SEARCH', 'ALL')):
+                continue
+
+            uid = dat[-1].split()
+            if not uid: continue
+            run('uid', ('FETCH', '%s' % uid[-1],
+                    '(FLAGS INTERNALDATE RFC822.SIZE RFC822.HEADER RFC822.TEXT)'))
+
+        print('\nAll tests OK.')
+
+    except:
+        print('\nTests failed.')
+
+        if not Debug:
+            print('''
+If you would like to see debugging output,
+try: %s -d5
+''' % sys.argv[0])
+
+        raise