Sync contrib/tools/python3 layout with upstream

* Move src/ subdir contents to the top of the layout
* Rename self-written lib -> lib2 to avoid CaseFolding warning from the VCS
* Regenerate contrib/libs/python proxy-headers accordingly
4ccc62ac1511abcf0fed14ccade38e984e088f1e

1 files changed, 793 insertions, 0 deletions

diff --git a/contrib/tools/python3/Lib/uuid.py b/contrib/tools/python3/Lib/uuid.py
new file mode 100644
index 0000000000..470bc0d685
--- /dev/null
+++ b/contrib/tools/python3/Lib/uuid.py
@@ -0,0 +1,793 @@
+r"""UUID objects (universally unique identifiers) according to RFC 4122.
+
+This module provides immutable UUID objects (class UUID) and the functions
+uuid1(), uuid3(), uuid4(), uuid5() for generating version 1, 3, 4, and 5
+UUIDs as specified in RFC 4122.
+
+If all you want is a unique ID, you should probably call uuid1() or uuid4().
+Note that uuid1() may compromise privacy since it creates a UUID containing
+the computer's network address.  uuid4() creates a random UUID.
+
+Typical usage:
+
+    >>> import uuid
+
+    # make a UUID based on the host ID and current time
+    >>> uuid.uuid1()    # doctest: +SKIP
+    UUID('a8098c1a-f86e-11da-bd1a-00112444be1e')
+
+    # make a UUID using an MD5 hash of a namespace UUID and a name
+    >>> uuid.uuid3(uuid.NAMESPACE_DNS, 'python.org')
+    UUID('6fa459ea-ee8a-3ca4-894e-db77e160355e')
+
+    # make a random UUID
+    >>> uuid.uuid4()    # doctest: +SKIP
+    UUID('16fd2706-8baf-433b-82eb-8c7fada847da')
+
+    # make a UUID using a SHA-1 hash of a namespace UUID and a name
+    >>> uuid.uuid5(uuid.NAMESPACE_DNS, 'python.org')
+    UUID('886313e1-3b8a-5372-9b90-0c9aee199e5d')
+
+    # make a UUID from a string of hex digits (braces and hyphens ignored)
+    >>> x = uuid.UUID('{00010203-0405-0607-0809-0a0b0c0d0e0f}')
+
+    # convert a UUID to a string of hex digits in standard form
+    >>> str(x)
+    '00010203-0405-0607-0809-0a0b0c0d0e0f'
+
+    # get the raw 16 bytes of the UUID
+    >>> x.bytes
+    b'\x00\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\x0c\r\x0e\x0f'
+
+    # make a UUID from a 16-byte string
+    >>> uuid.UUID(bytes=x.bytes)
+    UUID('00010203-0405-0607-0809-0a0b0c0d0e0f')
+"""
+
+import os
+import sys
+
+from enum import Enum, _simple_enum
+
+
+__author__ = 'Ka-Ping Yee <ping@zesty.ca>'
+
+# The recognized platforms - known behaviors
+if sys.platform in ('win32', 'darwin', 'emscripten', 'wasi'):
+    _AIX = _LINUX = False
+else:
+    import platform
+    _platform_system = platform.system()
+    _AIX     = _platform_system == 'AIX'
+    _LINUX   = _platform_system == 'Linux'
+
+_MAC_DELIM = b':'
+_MAC_OMITS_LEADING_ZEROES = False
+if _AIX:
+    _MAC_DELIM = b'.'
+    _MAC_OMITS_LEADING_ZEROES = True
+
+RESERVED_NCS, RFC_4122, RESERVED_MICROSOFT, RESERVED_FUTURE = [
+    'reserved for NCS compatibility', 'specified in RFC 4122',
+    'reserved for Microsoft compatibility', 'reserved for future definition']
+
+int_ = int      # The built-in int type
+bytes_ = bytes  # The built-in bytes type
+
+
+@_simple_enum(Enum)
+class SafeUUID:
+    safe = 0
+    unsafe = -1
+    unknown = None
+
+
+class UUID:
+    """Instances of the UUID class represent UUIDs as specified in RFC 4122.
+    UUID objects are immutable, hashable, and usable as dictionary keys.
+    Converting a UUID to a string with str() yields something in the form
+    '12345678-1234-1234-1234-123456789abc'.  The UUID constructor accepts
+    five possible forms: a similar string of hexadecimal digits, or a tuple
+    of six integer fields (with 32-bit, 16-bit, 16-bit, 8-bit, 8-bit, and
+    48-bit values respectively) as an argument named 'fields', or a string
+    of 16 bytes (with all the integer fields in big-endian order) as an
+    argument named 'bytes', or a string of 16 bytes (with the first three
+    fields in little-endian order) as an argument named 'bytes_le', or a
+    single 128-bit integer as an argument named 'int'.
+
+    UUIDs have these read-only attributes:
+
+        bytes       the UUID as a 16-byte string (containing the six
+                    integer fields in big-endian byte order)
+
+        bytes_le    the UUID as a 16-byte string (with time_low, time_mid,
+                    and time_hi_version in little-endian byte order)
+
+        fields      a tuple of the six integer fields of the UUID,
+                    which are also available as six individual attributes
+                    and two derived attributes:
+
+            time_low                the first 32 bits of the UUID
+            time_mid                the next 16 bits of the UUID
+            time_hi_version         the next 16 bits of the UUID
+            clock_seq_hi_variant    the next 8 bits of the UUID
+            clock_seq_low           the next 8 bits of the UUID
+            node                    the last 48 bits of the UUID
+
+            time                    the 60-bit timestamp
+            clock_seq               the 14-bit sequence number
+
+        hex         the UUID as a 32-character hexadecimal string
+
+        int         the UUID as a 128-bit integer
+
+        urn         the UUID as a URN as specified in RFC 4122
+
+        variant     the UUID variant (one of the constants RESERVED_NCS,
+                    RFC_4122, RESERVED_MICROSOFT, or RESERVED_FUTURE)
+
+        version     the UUID version number (1 through 5, meaningful only
+                    when the variant is RFC_4122)
+
+        is_safe     An enum indicating whether the UUID has been generated in
+                    a way that is safe for multiprocessing applications, via
+                    uuid_generate_time_safe(3).
+    """
+
+    __slots__ = ('int', 'is_safe', '__weakref__')
+
+    def __init__(self, hex=None, bytes=None, bytes_le=None, fields=None,
+                       int=None, version=None,
+                       *, is_safe=SafeUUID.unknown):
+        r"""Create a UUID from either a string of 32 hexadecimal digits,
+        a string of 16 bytes as the 'bytes' argument, a string of 16 bytes
+        in little-endian order as the 'bytes_le' argument, a tuple of six
+        integers (32-bit time_low, 16-bit time_mid, 16-bit time_hi_version,
+        8-bit clock_seq_hi_variant, 8-bit clock_seq_low, 48-bit node) as
+        the 'fields' argument, or a single 128-bit integer as the 'int'
+        argument.  When a string of hex digits is given, curly braces,
+        hyphens, and a URN prefix are all optional.  For example, these
+        expressions all yield the same UUID:
+
+        UUID('{12345678-1234-5678-1234-567812345678}')
+        UUID('12345678123456781234567812345678')
+        UUID('urn:uuid:12345678-1234-5678-1234-567812345678')
+        UUID(bytes='\x12\x34\x56\x78'*4)
+        UUID(bytes_le='\x78\x56\x34\x12\x34\x12\x78\x56' +
+                      '\x12\x34\x56\x78\x12\x34\x56\x78')
+        UUID(fields=(0x12345678, 0x1234, 0x5678, 0x12, 0x34, 0x567812345678))
+        UUID(int=0x12345678123456781234567812345678)
+
+        Exactly one of 'hex', 'bytes', 'bytes_le', 'fields', or 'int' must
+        be given.  The 'version' argument is optional; if given, the resulting
+        UUID will have its variant and version set according to RFC 4122,
+        overriding the given 'hex', 'bytes', 'bytes_le', 'fields', or 'int'.
+
+        is_safe is an enum exposed as an attribute on the instance.  It
+        indicates whether the UUID has been generated in a way that is safe
+        for multiprocessing applications, via uuid_generate_time_safe(3).
+        """
+
+        if [hex, bytes, bytes_le, fields, int].count(None) != 4:
+            raise TypeError('one of the hex, bytes, bytes_le, fields, '
+                            'or int arguments must be given')
+        if hex is not None:
+            hex = hex.replace('urn:', '').replace('uuid:', '')
+            hex = hex.strip('{}').replace('-', '')
+            if len(hex) != 32:
+                raise ValueError('badly formed hexadecimal UUID string')
+            int = int_(hex, 16)
+        if bytes_le is not None:
+            if len(bytes_le) != 16:
+                raise ValueError('bytes_le is not a 16-char string')
+            bytes = (bytes_le[4-1::-1] + bytes_le[6-1:4-1:-1] +
+                     bytes_le[8-1:6-1:-1] + bytes_le[8:])
+        if bytes is not None:
+            if len(bytes) != 16:
+                raise ValueError('bytes is not a 16-char string')
+            assert isinstance(bytes, bytes_), repr(bytes)
+            int = int_.from_bytes(bytes)  # big endian
+        if fields is not None:
+            if len(fields) != 6:
+                raise ValueError('fields is not a 6-tuple')
+            (time_low, time_mid, time_hi_version,
+             clock_seq_hi_variant, clock_seq_low, node) = fields
+            if not 0 <= time_low < 1<<32:
+                raise ValueError('field 1 out of range (need a 32-bit value)')
+            if not 0 <= time_mid < 1<<16:
+                raise ValueError('field 2 out of range (need a 16-bit value)')
+            if not 0 <= time_hi_version < 1<<16:
+                raise ValueError('field 3 out of range (need a 16-bit value)')
+            if not 0 <= clock_seq_hi_variant < 1<<8:
+                raise ValueError('field 4 out of range (need an 8-bit value)')
+            if not 0 <= clock_seq_low < 1<<8:
+                raise ValueError('field 5 out of range (need an 8-bit value)')
+            if not 0 <= node < 1<<48:
+                raise ValueError('field 6 out of range (need a 48-bit value)')
+            clock_seq = (clock_seq_hi_variant << 8) | clock_seq_low
+            int = ((time_low << 96) | (time_mid << 80) |
+                   (time_hi_version << 64) | (clock_seq << 48) | node)
+        if int is not None:
+            if not 0 <= int < 1<<128:
+                raise ValueError('int is out of range (need a 128-bit value)')
+        if version is not None:
+            if not 1 <= version <= 5:
+                raise ValueError('illegal version number')
+            # Set the variant to RFC 4122.
+            int &= ~(0xc000 << 48)
+            int |= 0x8000 << 48
+            # Set the version number.
+            int &= ~(0xf000 << 64)
+            int |= version << 76
+        object.__setattr__(self, 'int', int)
+        object.__setattr__(self, 'is_safe', is_safe)
+
+    def __getstate__(self):
+        d = {'int': self.int}
+        if self.is_safe != SafeUUID.unknown:
+            # is_safe is a SafeUUID instance.  Return just its value, so that
+            # it can be un-pickled in older Python versions without SafeUUID.
+            d['is_safe'] = self.is_safe.value
+        return d
+
+    def __setstate__(self, state):
+        object.__setattr__(self, 'int', state['int'])
+        # is_safe was added in 3.7; it is also omitted when it is "unknown"
+        object.__setattr__(self, 'is_safe',
+                           SafeUUID(state['is_safe'])
+                           if 'is_safe' in state else SafeUUID.unknown)
+
+    def __eq__(self, other):
+        if isinstance(other, UUID):
+            return self.int == other.int
+        return NotImplemented
+
+    # Q. What's the value of being able to sort UUIDs?
+    # A. Use them as keys in a B-Tree or similar mapping.
+
+    def __lt__(self, other):
+        if isinstance(other, UUID):
+            return self.int < other.int
+        return NotImplemented
+
+    def __gt__(self, other):
+        if isinstance(other, UUID):
+            return self.int > other.int
+        return NotImplemented
+
+    def __le__(self, other):
+        if isinstance(other, UUID):
+            return self.int <= other.int
+        return NotImplemented
+
+    def __ge__(self, other):
+        if isinstance(other, UUID):
+            return self.int >= other.int
+        return NotImplemented
+
+    def __hash__(self):
+        return hash(self.int)
+
+    def __int__(self):
+        return self.int
+
+    def __repr__(self):
+        return '%s(%r)' % (self.__class__.__name__, str(self))
+
+    def __setattr__(self, name, value):
+        raise TypeError('UUID objects are immutable')
+
+    def __str__(self):
+        hex = '%032x' % self.int
+        return '%s-%s-%s-%s-%s' % (
+            hex[:8], hex[8:12], hex[12:16], hex[16:20], hex[20:])
+
+    @property
+    def bytes(self):
+        return self.int.to_bytes(16)  # big endian
+
+    @property
+    def bytes_le(self):
+        bytes = self.bytes
+        return (bytes[4-1::-1] + bytes[6-1:4-1:-1] + bytes[8-1:6-1:-1] +
+                bytes[8:])
+
+    @property
+    def fields(self):
+        return (self.time_low, self.time_mid, self.time_hi_version,
+                self.clock_seq_hi_variant, self.clock_seq_low, self.node)
+
+    @property
+    def time_low(self):
+        return self.int >> 96
+
+    @property
+    def time_mid(self):
+        return (self.int >> 80) & 0xffff
+
+    @property
+    def time_hi_version(self):
+        return (self.int >> 64) & 0xffff
+
+    @property
+    def clock_seq_hi_variant(self):
+        return (self.int >> 56) & 0xff
+
+    @property
+    def clock_seq_low(self):
+        return (self.int >> 48) & 0xff
+
+    @property
+    def time(self):
+        return (((self.time_hi_version & 0x0fff) << 48) |
+                (self.time_mid << 32) | self.time_low)
+
+    @property
+    def clock_seq(self):
+        return (((self.clock_seq_hi_variant & 0x3f) << 8) |
+                self.clock_seq_low)
+
+    @property
+    def node(self):
+        return self.int & 0xffffffffffff
+
+    @property
+    def hex(self):
+        return '%032x' % self.int
+
+    @property
+    def urn(self):
+        return 'urn:uuid:' + str(self)
+
+    @property
+    def variant(self):
+        if not self.int & (0x8000 << 48):
+            return RESERVED_NCS
+        elif not self.int & (0x4000 << 48):
+            return RFC_4122
+        elif not self.int & (0x2000 << 48):
+            return RESERVED_MICROSOFT
+        else:
+            return RESERVED_FUTURE
+
+    @property
+    def version(self):
+        # The version bits are only meaningful for RFC 4122 UUIDs.
+        if self.variant == RFC_4122:
+            return int((self.int >> 76) & 0xf)
+
+
+def _get_command_stdout(command, *args):
+    import io, os, shutil, subprocess
+
+    try:
+        path_dirs = os.environ.get('PATH', os.defpath).split(os.pathsep)
+        path_dirs.extend(['/sbin', '/usr/sbin'])
+        executable = shutil.which(command, path=os.pathsep.join(path_dirs))
+        if executable is None:
+            return None
+        # LC_ALL=C to ensure English output, stderr=DEVNULL to prevent output
+        # on stderr (Note: we don't have an example where the words we search
+        # for are actually localized, but in theory some system could do so.)
+        env = dict(os.environ)
+        env['LC_ALL'] = 'C'
+        # Empty strings will be quoted by popen so we should just ommit it
+        if args != ('',):
+            command = (executable, *args)
+        else:
+            command = (executable,)
+        proc = subprocess.Popen(command,
+                                stdout=subprocess.PIPE,
+                                stderr=subprocess.DEVNULL,
+                                env=env)
+        if not proc:
+            return None
+        stdout, stderr = proc.communicate()
+        return io.BytesIO(stdout)
+    except (OSError, subprocess.SubprocessError):
+        return None
+
+
+# For MAC (a.k.a. IEEE 802, or EUI-48) addresses, the second least significant
+# bit of the first octet signifies whether the MAC address is universally (0)
+# or locally (1) administered.  Network cards from hardware manufacturers will
+# always be universally administered to guarantee global uniqueness of the MAC
+# address, but any particular machine may have other interfaces which are
+# locally administered.  An example of the latter is the bridge interface to
+# the Touch Bar on MacBook Pros.
+#
+# This bit works out to be the 42nd bit counting from 1 being the least
+# significant, or 1<<41.  We'll prefer universally administered MAC addresses
+# over locally administered ones since the former are globally unique, but
+# we'll return the first of the latter found if that's all the machine has.
+#
+# See https://en.wikipedia.org/wiki/MAC_address#Universal_vs._local_(U/L_bit)
+
+def _is_universal(mac):
+    return not (mac & (1 << 41))
+
+
+def _find_mac_near_keyword(command, args, keywords, get_word_index):
+    """Searches a command's output for a MAC address near a keyword.
+
+    Each line of words in the output is case-insensitively searched for
+    any of the given keywords.  Upon a match, get_word_index is invoked
+    to pick a word from the line, given the index of the match.  For
+    example, lambda i: 0 would get the first word on the line, while
+    lambda i: i - 1 would get the word preceding the keyword.
+    """
+    stdout = _get_command_stdout(command, args)
+    if stdout is None:
+        return None
+
+    first_local_mac = None
+    for line in stdout:
+        words = line.lower().rstrip().split()
+        for i in range(len(words)):
+            if words[i] in keywords:
+                try:
+                    word = words[get_word_index(i)]
+                    mac = int(word.replace(_MAC_DELIM, b''), 16)
+                except (ValueError, IndexError):
+                    # Virtual interfaces, such as those provided by
+                    # VPNs, do not have a colon-delimited MAC address
+                    # as expected, but a 16-byte HWAddr separated by
+                    # dashes. These should be ignored in favor of a
+                    # real MAC address
+                    pass
+                else:
+                    if _is_universal(mac):
+                        return mac
+                    first_local_mac = first_local_mac or mac
+    return first_local_mac or None
+
+
+def _parse_mac(word):
+    # Accept 'HH:HH:HH:HH:HH:HH' MAC address (ex: '52:54:00:9d:0e:67'),
+    # but reject IPv6 address (ex: 'fe80::5054:ff:fe9' or '123:2:3:4:5:6:7:8').
+    #
+    # Virtual interfaces, such as those provided by VPNs, do not have a
+    # colon-delimited MAC address as expected, but a 16-byte HWAddr separated
+    # by dashes. These should be ignored in favor of a real MAC address
+    parts = word.split(_MAC_DELIM)
+    if len(parts) != 6:
+        return
+    if _MAC_OMITS_LEADING_ZEROES:
+        # (Only) on AIX the macaddr value given is not prefixed by 0, e.g.
+        # en0   1500  link#2      fa.bc.de.f7.62.4 110854824     0 160133733     0     0
+        # not
+        # en0   1500  link#2      fa.bc.de.f7.62.04 110854824     0 160133733     0     0
+        if not all(1 <= len(part) <= 2 for part in parts):
+            return
+        hexstr = b''.join(part.rjust(2, b'0') for part in parts)
+    else:
+        if not all(len(part) == 2 for part in parts):
+            return
+        hexstr = b''.join(parts)
+    try:
+        return int(hexstr, 16)
+    except ValueError:
+        return
+
+
+def _find_mac_under_heading(command, args, heading):
+    """Looks for a MAC address under a heading in a command's output.
+
+    The first line of words in the output is searched for the given
+    heading. Words at the same word index as the heading in subsequent
+    lines are then examined to see if they look like MAC addresses.
+    """
+    stdout = _get_command_stdout(command, args)
+    if stdout is None:
+        return None
+
+    keywords = stdout.readline().rstrip().split()
+    try:
+        column_index = keywords.index(heading)
+    except ValueError:
+        return None
+
+    first_local_mac = None
+    for line in stdout:
+        words = line.rstrip().split()
+        try:
+            word = words[column_index]
+        except IndexError:
+            continue
+
+        mac = _parse_mac(word)
+        if mac is None:
+            continue
+        if _is_universal(mac):
+            return mac
+        if first_local_mac is None:
+            first_local_mac = mac
+
+    return first_local_mac
+
+
+# The following functions call external programs to 'get' a macaddr value to
+# be used as basis for an uuid
+def _ifconfig_getnode():
+    """Get the hardware address on Unix by running ifconfig."""
+    # This works on Linux ('' or '-a'), Tru64 ('-av'), but not all Unixes.
+    keywords = (b'hwaddr', b'ether', b'address:', b'lladdr')
+    for args in ('', '-a', '-av'):
+        mac = _find_mac_near_keyword('ifconfig', args, keywords, lambda i: i+1)
+        if mac:
+            return mac
+    return None
+
+def _ip_getnode():
+    """Get the hardware address on Unix by running ip."""
+    # This works on Linux with iproute2.
+    mac = _find_mac_near_keyword('ip', 'link', [b'link/ether'], lambda i: i+1)
+    if mac:
+        return mac
+    return None
+
+def _arp_getnode():
+    """Get the hardware address on Unix by running arp."""
+    import os, socket
+    if not hasattr(socket, "gethostbyname"):
+        return None
+    try:
+        ip_addr = socket.gethostbyname(socket.gethostname())
+    except OSError:
+        return None
+
+    # Try getting the MAC addr from arp based on our IP address (Solaris).
+    mac = _find_mac_near_keyword('arp', '-an', [os.fsencode(ip_addr)], lambda i: -1)
+    if mac:
+        return mac
+
+    # This works on OpenBSD
+    mac = _find_mac_near_keyword('arp', '-an', [os.fsencode(ip_addr)], lambda i: i+1)
+    if mac:
+        return mac
+
+    # This works on Linux, FreeBSD and NetBSD
+    mac = _find_mac_near_keyword('arp', '-an', [os.fsencode('(%s)' % ip_addr)],
+                    lambda i: i+2)
+    # Return None instead of 0.
+    if mac:
+        return mac
+    return None
+
+def _lanscan_getnode():
+    """Get the hardware address on Unix by running lanscan."""
+    # This might work on HP-UX.
+    return _find_mac_near_keyword('lanscan', '-ai', [b'lan0'], lambda i: 0)
+
+def _netstat_getnode():
+    """Get the hardware address on Unix by running netstat."""
+    # This works on AIX and might work on Tru64 UNIX.
+    return _find_mac_under_heading('netstat', '-ian', b'Address')
+
+def _ipconfig_getnode():
+    """[DEPRECATED] Get the hardware address on Windows."""
+    # bpo-40501: UuidCreateSequential() is now the only supported approach
+    return _windll_getnode()
+
+def _netbios_getnode():
+    """[DEPRECATED] Get the hardware address on Windows."""
+    # bpo-40501: UuidCreateSequential() is now the only supported approach
+    return _windll_getnode()
+
+
+# Import optional C extension at toplevel, to help disabling it when testing
+try:
+    import _uuid
+    _generate_time_safe = getattr(_uuid, "generate_time_safe", None)
+    _UuidCreate = getattr(_uuid, "UuidCreate", None)
+    _has_uuid_generate_time_safe = _uuid.has_uuid_generate_time_safe
+except ImportError:
+    _uuid = None
+    _generate_time_safe = None
+    _UuidCreate = None
+    _has_uuid_generate_time_safe = None
+
+
+def _load_system_functions():
+    """[DEPRECATED] Platform-specific functions loaded at import time"""
+
+
+def _unix_getnode():
+    """Get the hardware address on Unix using the _uuid extension module."""
+    if _generate_time_safe:
+        uuid_time, _ = _generate_time_safe()
+        return UUID(bytes=uuid_time).node
+
+def _windll_getnode():
+    """Get the hardware address on Windows using the _uuid extension module."""
+    if _UuidCreate:
+        uuid_bytes = _UuidCreate()
+        return UUID(bytes_le=uuid_bytes).node
+
+def _random_getnode():
+    """Get a random node ID."""
+    # RFC 4122, $4.1.6 says "For systems with no IEEE address, a randomly or
+    # pseudo-randomly generated value may be used; see Section 4.5.  The
+    # multicast bit must be set in such addresses, in order that they will
+    # never conflict with addresses obtained from network cards."
+    #
+    # The "multicast bit" of a MAC address is defined to be "the least
+    # significant bit of the first octet".  This works out to be the 41st bit
+    # counting from 1 being the least significant bit, or 1<<40.
+    #
+    # See https://en.wikipedia.org/w/index.php?title=MAC_address&oldid=1128764812#Universal_vs._local_(U/L_bit)
+    import random
+    return random.getrandbits(48) | (1 << 40)
+
+
+# _OS_GETTERS, when known, are targeted for a specific OS or platform.
+# The order is by 'common practice' on the specified platform.
+# Note: 'posix' and 'windows' _OS_GETTERS are prefixed by a dll/dlload() method
+# which, when successful, means none of these "external" methods are called.
+# _GETTERS is (also) used by test_uuid.py to SkipUnless(), e.g.,
+#     @unittest.skipUnless(_uuid._ifconfig_getnode in _uuid._GETTERS, ...)
+if _LINUX:
+    _OS_GETTERS = [_ip_getnode, _ifconfig_getnode]
+elif sys.platform == 'darwin':
+    _OS_GETTERS = [_ifconfig_getnode, _arp_getnode, _netstat_getnode]
+elif sys.platform == 'win32':
+    # bpo-40201: _windll_getnode will always succeed, so these are not needed
+    _OS_GETTERS = []
+elif _AIX:
+    _OS_GETTERS = [_netstat_getnode]
+else:
+    _OS_GETTERS = [_ifconfig_getnode, _ip_getnode, _arp_getnode,
+                   _netstat_getnode, _lanscan_getnode]
+if os.name == 'posix':
+    _GETTERS = [_unix_getnode] + _OS_GETTERS
+elif os.name == 'nt':
+    _GETTERS = [_windll_getnode] + _OS_GETTERS
+else:
+    _GETTERS = _OS_GETTERS
+
+_node = None
+
+def getnode():
+    """Get the hardware address as a 48-bit positive integer.
+
+    The first time this runs, it may launch a separate program, which could
+    be quite slow.  If all attempts to obtain the hardware address fail, we
+    choose a random 48-bit number with its eighth bit set to 1 as recommended
+    in RFC 4122.
+    """
+    global _node
+    if _node is not None:
+        return _node
+
+    for getter in _GETTERS + [_random_getnode]:
+        try:
+            _node = getter()
+        except:
+            continue
+        if (_node is not None) and (0 <= _node < (1 << 48)):
+            return _node
+    assert False, '_random_getnode() returned invalid value: {}'.format(_node)
+
+
+_last_timestamp = None
+
+def uuid1(node=None, clock_seq=None):
+    """Generate a UUID from a host ID, sequence number, and the current time.
+    If 'node' is not given, getnode() is used to obtain the hardware
+    address.  If 'clock_seq' is given, it is used as the sequence number;
+    otherwise a random 14-bit sequence number is chosen."""
+
+    # When the system provides a version-1 UUID generator, use it (but don't
+    # use UuidCreate here because its UUIDs don't conform to RFC 4122).
+    if _generate_time_safe is not None and node is clock_seq is None:
+        uuid_time, safely_generated = _generate_time_safe()
+        try:
+            is_safe = SafeUUID(safely_generated)
+        except ValueError:
+            is_safe = SafeUUID.unknown
+        return UUID(bytes=uuid_time, is_safe=is_safe)
+
+    global _last_timestamp
+    import time
+    nanoseconds = time.time_ns()
+    # 0x01b21dd213814000 is the number of 100-ns intervals between the
+    # UUID epoch 1582-10-15 00:00:00 and the Unix epoch 1970-01-01 00:00:00.
+    timestamp = nanoseconds // 100 + 0x01b21dd213814000
+    if _last_timestamp is not None and timestamp <= _last_timestamp:
+        timestamp = _last_timestamp + 1
+    _last_timestamp = timestamp
+    if clock_seq is None:
+        import random
+        clock_seq = random.getrandbits(14) # instead of stable storage
+    time_low = timestamp & 0xffffffff
+    time_mid = (timestamp >> 32) & 0xffff
+    time_hi_version = (timestamp >> 48) & 0x0fff
+    clock_seq_low = clock_seq & 0xff
+    clock_seq_hi_variant = (clock_seq >> 8) & 0x3f
+    if node is None:
+        node = getnode()
+    return UUID(fields=(time_low, time_mid, time_hi_version,
+                        clock_seq_hi_variant, clock_seq_low, node), version=1)
+
+def uuid3(namespace, name):
+    """Generate a UUID from the MD5 hash of a namespace UUID and a name."""
+    if isinstance(name, str):
+        name = bytes(name, "utf-8")
+    from hashlib import md5
+    digest = md5(
+        namespace.bytes + name,
+        usedforsecurity=False
+    ).digest()
+    return UUID(bytes=digest[:16], version=3)
+
+def uuid4():
+    """Generate a random UUID."""
+    return UUID(bytes=os.urandom(16), version=4)
+
+def uuid5(namespace, name):
+    """Generate a UUID from the SHA-1 hash of a namespace UUID and a name."""
+    if isinstance(name, str):
+        name = bytes(name, "utf-8")
+    from hashlib import sha1
+    hash = sha1(namespace.bytes + name).digest()
+    return UUID(bytes=hash[:16], version=5)
+
+
+def main():
+    """Run the uuid command line interface."""
+    uuid_funcs = {
+        "uuid1": uuid1,
+        "uuid3": uuid3,
+        "uuid4": uuid4,
+        "uuid5": uuid5
+    }
+    uuid_namespace_funcs = ("uuid3", "uuid5")
+    namespaces = {
+        "@dns": NAMESPACE_DNS,
+        "@url": NAMESPACE_URL,
+        "@oid": NAMESPACE_OID,
+        "@x500": NAMESPACE_X500
+    }
+
+    import argparse
+    parser = argparse.ArgumentParser(
+        description="Generates a uuid using the selected uuid function.")
+    parser.add_argument("-u", "--uuid", choices=uuid_funcs.keys(), default="uuid4",
+                        help="The function to use to generate the uuid. "
+                        "By default uuid4 function is used.")
+    parser.add_argument("-n", "--namespace",
+                        help="The namespace is a UUID, or '@ns' where 'ns' is a "
+                        "well-known predefined UUID addressed by namespace name. "
+                        "Such as @dns, @url, @oid, and @x500. "
+                        "Only required for uuid3/uuid5 functions.")
+    parser.add_argument("-N", "--name",
+                        help="The name used as part of generating the uuid. "
+                        "Only required for uuid3/uuid5 functions.")
+
+    args = parser.parse_args()
+    uuid_func = uuid_funcs[args.uuid]
+    namespace = args.namespace
+    name = args.name
+
+    if args.uuid in uuid_namespace_funcs:
+        if not namespace or not name:
+            parser.error(
+                "Incorrect number of arguments. "
+                f"{args.uuid} requires a namespace and a name. "
+                "Run 'python -m uuid -h' for more information."
+            )
+        namespace = namespaces[namespace] if namespace in namespaces else UUID(namespace)
+        print(uuid_func(namespace, name))
+    else:
+        print(uuid_func())
+
+
+# The following standard UUIDs are for use with uuid3() or uuid5().
+
+NAMESPACE_DNS = UUID('6ba7b810-9dad-11d1-80b4-00c04fd430c8')
+NAMESPACE_URL = UUID('6ba7b811-9dad-11d1-80b4-00c04fd430c8')
+NAMESPACE_OID = UUID('6ba7b812-9dad-11d1-80b4-00c04fd430c8')
+NAMESPACE_X500 = UUID('6ba7b814-9dad-11d1-80b4-00c04fd430c8')
+
+if __name__ == "__main__":
+    main()