diff --git a/mercurial/thirdparty/cbor/.travis.yml b/mercurial/thirdparty/cbor/.travis.yml
new file mode 100644
--- /dev/null
+++ b/mercurial/thirdparty/cbor/.travis.yml
@@ -0,0 +1,58 @@
+language: python
+sudo: false
+
+stages:
+  - name: test
+  - name: deploy to pypi
+    if: type = push AND tag =~ ^\d+\.\d+\.\d+
+
+jobs:
+  fast_finish: true
+  include:
+    - env: TOXENV=flake8
+
+    - env: TOXENV=pypy
+      python: pypy3
+
+    - env: TOXENV=pypy3
+      python: pypy3
+
+    - env: TOXENV=py27
+      python: "2.7"
+      after_success: &after_success
+        - pip install coveralls
+        - coveralls
+
+    - env: TOXENV=py33
+      python: "3.3"
+      after_success: *after_success
+
+    - env: TOXENV=py34
+      python: "3.4"
+      after_success: *after_success
+
+    - env: TOXENV=py35
+      python: "3.5"
+      after_success: *after_success
+
+    - env: TOXENV=py36
+      python: "3.6"
+      after_success: *after_success
+
+    - stage: deploy to pypi
+      install: pip install "setuptools >= 36.2.7"
+      script: skip
+      deploy:
+        provider: pypi
+        user: agronholm
+        password:
+          secure: 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
+        distributions: sdist bdist_wheel
+        on:
+          tags: true
+
+install:
+  - pip install "setuptools >= 36.2.7"
+  - pip install tox
+
+script: tox
diff --git a/mercurial/thirdparty/cbor/LICENSE.txt b/mercurial/thirdparty/cbor/LICENSE.txt
new file mode 100644
--- /dev/null
+++ b/mercurial/thirdparty/cbor/LICENSE.txt
@@ -0,0 +1,19 @@
+This is the MIT license: http://www.opensource.org/licenses/mit-license.php
+
+Copyright (c) Alex Grönholm
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this
+software and associated documentation files (the "Software"), to deal in the Software
+without restriction, including without limitation the rights to use, copy, modify, merge,
+publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
+to whom the Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or
+substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
+FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
diff --git a/mercurial/thirdparty/cbor/README.rst b/mercurial/thirdparty/cbor/README.rst
new file mode 100644
--- /dev/null
+++ b/mercurial/thirdparty/cbor/README.rst
@@ -0,0 +1,24 @@
+.. image:: https://travis-ci.org/agronholm/cbor2.svg?branch=master
+  :target: https://travis-ci.org/agronholm/cbor2
+  :alt: Build Status
+.. image:: https://coveralls.io/repos/github/agronholm/cbor2/badge.svg?branch=master
+  :target: https://coveralls.io/github/agronholm/cbor2?branch=master
+  :alt: Code Coverage
+
+This library provides encoding and decoding for the Concise Binary Object Representation (CBOR)
+(`RFC 7049`_) serialization format.
+
+There exists another Python CBOR implementation (cbor) which is faster on CPython due to its C
+extensions. On PyPy, cbor2 and cbor are almost identical in performance. The other implementation
+also lacks documentation and a comprehensive test suite, does not support most standard extension
+tags and is known to crash (segfault) when passed a cyclic structure (say, a list containing
+itself).
+
+.. _RFC 7049: https://tools.ietf.org/html/rfc7049
+
+Project links
+-------------
+
+* `Documentation <http://cbor2.readthedocs.org/>`_
+* `Source code <https://github.com/agronholm/cbor2>`_
+* `Issue tracker <https://github.com/agronholm/cbor2/issues>`_
diff --git a/mercurial/thirdparty/cbor/cbor2/__init__.py b/mercurial/thirdparty/cbor/cbor2/__init__.py
new file mode 100644
--- /dev/null
+++ b/mercurial/thirdparty/cbor/cbor2/__init__.py
@@ -0,0 +1,3 @@
+from .decoder import load, loads, CBORDecoder, CBORDecodeError  # noqa
+from .encoder import dump, dumps, CBOREncoder, CBOREncodeError, shareable_encoder  # noqa
+from .types import CBORTag, CBORSimpleValue, undefined  # noqa
diff --git a/mercurial/thirdparty/cbor/cbor2/compat.py b/mercurial/thirdparty/cbor/cbor2/compat.py
new file mode 100644
--- /dev/null
+++ b/mercurial/thirdparty/cbor/cbor2/compat.py
@@ -0,0 +1,101 @@
+from math import ldexp
+import struct
+import sys
+
+
+if sys.version_info.major < 3:
+    from datetime import tzinfo, timedelta
+
+    class timezone(tzinfo):
+        def __init__(self, offset):
+            self.offset = offset
+
+        def utcoffset(self, dt):
+            return self.offset
+
+        def dst(self, dt):
+            return timedelta(0)
+
+        def tzname(self, dt):
+            return 'UTC+00:00'
+
+    def as_unicode(string):
+        return string.decode('utf-8')
+
+    def iteritems(self):
+        return self.iteritems()
+
+    def bytes_from_list(values):
+        return bytes(bytearray(values))
+
+    byte_as_integer = ord
+    timezone.utc = timezone(timedelta(0))
+    xrange = xrange  # noqa: F821
+    long = long  # noqa: F821
+    unicode = unicode  # noqa: F821
+else:
+    from datetime import timezone
+
+    def byte_as_integer(bytestr):
+        return bytestr[0]
+
+    def as_unicode(string):
+        return string
+
+    def iteritems(self):
+        return self.items()
+
+    xrange = range
+    long = int
+    unicode = str
+    bytes_from_list = bytes
+
+
+if sys.version_info.major >= 3 and sys.version_info.minor >= 6:
+    # Python 3.6 added 16 bit floating point to struct
+
+    def pack_float16(value):
+        try:
+            return struct.pack('>Be', 0xf9, value)
+        except OverflowError:
+            return False
+
+    def unpack_float16(payload):
+        return struct.unpack('>e', payload)[0]
+else:
+    def pack_float16(value):
+        # Based on node-cbor by hildjj
+        # which was based in turn on Carsten Borman's cn-cbor
+        u32 = struct.pack('>f', value)
+        u = struct.unpack('>I', u32)[0]
+
+        if u & 0x1FFF != 0:
+            return False
+
+        s16 = (u >> 16) & 0x8000
+        exponent = (u >> 23) & 0xff
+        mantissa = u & 0x7fffff
+
+        if 113 <= exponent <= 142:
+            s16 += ((exponent - 112) << 10) + (mantissa >> 13)
+        elif 103 <= exponent < 113:
+            if mantissa & ((1 << (126 - exponent)) - 1):
+                return False
+
+            s16 += ((mantissa + 0x800000) >> (126 - exponent))
+        else:
+            return False
+
+        return struct.pack('>BH', 0xf9, s16)
+
+    def unpack_float16(payload):
+        # Code adapted from RFC 7049, appendix D
+        def decode_single(single):
+            return struct.unpack("!f", struct.pack("!I", single))[0]
+
+        payload = struct.unpack('>H', payload)[0]
+        value = (payload & 0x7fff) << 13 | (payload & 0x8000) << 16
+        if payload & 0x7c00 != 0x7c00:
+            return ldexp(decode_single(value), 112)
+
+        return decode_single(value | 0x7f800000)
diff --git a/mercurial/thirdparty/cbor/cbor2/decoder.py b/mercurial/thirdparty/cbor/cbor2/decoder.py
new file mode 100644
--- /dev/null
+++ b/mercurial/thirdparty/cbor/cbor2/decoder.py
@@ -0,0 +1,407 @@
+import re
+import struct
+from datetime import datetime, timedelta
+from io import BytesIO
+
+from .compat import timezone, xrange, byte_as_integer, unpack_float16
+from .types import CBORTag, undefined, break_marker, CBORSimpleValue
+
+timestamp_re = re.compile(r'^(\d{4})-(\d\d)-(\d\d)T(\d\d):(\d\d):(\d\d)'
+                          r'(?:\.(\d+))?(?:Z|([+-]\d\d):(\d\d))$')
+
+
+class CBORDecodeError(Exception):
+    """Raised when an error occurs deserializing a CBOR datastream."""
+
+
+def decode_uint(decoder, subtype, shareable_index=None, allow_indefinite=False):
+    # Major tag 0
+    if subtype < 24:
+        return subtype
+    elif subtype == 24:
+        return struct.unpack('>B', decoder.read(1))[0]
+    elif subtype == 25:
+        return struct.unpack('>H', decoder.read(2))[0]
+    elif subtype == 26:
+        return struct.unpack('>L', decoder.read(4))[0]
+    elif subtype == 27:
+        return struct.unpack('>Q', decoder.read(8))[0]
+    elif subtype == 31 and allow_indefinite:
+        return None
+    else:
+        raise CBORDecodeError('unknown unsigned integer subtype 0x%x' % subtype)
+
+
+def decode_negint(decoder, subtype, shareable_index=None):
+    # Major tag 1
+    uint = decode_uint(decoder, subtype)
+    return -uint - 1
+
+
+def decode_bytestring(decoder, subtype, shareable_index=None):
+    # Major tag 2
+    length = decode_uint(decoder, subtype, allow_indefinite=True)
+    if length is None:
+        # Indefinite length
+        buf = bytearray()
+        while True:
+            initial_byte = byte_as_integer(decoder.read(1))
+            if initial_byte == 255:
+                return buf
+            else:
+                length = decode_uint(decoder, initial_byte & 31)
+                value = decoder.read(length)
+                buf.extend(value)
+    else:
+        return decoder.read(length)
+
+
+def decode_string(decoder, subtype, shareable_index=None):
+    # Major tag 3
+    return decode_bytestring(decoder, subtype).decode('utf-8')
+
+
+def decode_array(decoder, subtype, shareable_index=None):
+    # Major tag 4
+    items = []
+    decoder.set_shareable(shareable_index, items)
+    length = decode_uint(decoder, subtype, allow_indefinite=True)
+    if length is None:
+        # Indefinite length
+        while True:
+            value = decoder.decode()
+            if value is break_marker:
+                break
+            else:
+                items.append(value)
+    else:
+        for _ in xrange(length):
+            item = decoder.decode()
+            items.append(item)
+
+    return items
+
+
+def decode_map(decoder, subtype, shareable_index=None):
+    # Major tag 5
+    dictionary = {}
+    decoder.set_shareable(shareable_index, dictionary)
+    length = decode_uint(decoder, subtype, allow_indefinite=True)
+    if length is None:
+        # Indefinite length
+        while True:
+            key = decoder.decode()
+            if key is break_marker:
+                break
+            else:
+                value = decoder.decode()
+                dictionary[key] = value
+    else:
+        for _ in xrange(length):
+            key = decoder.decode()
+            value = decoder.decode()
+            dictionary[key] = value
+
+    if decoder.object_hook:
+        return decoder.object_hook(decoder, dictionary)
+    else:
+        return dictionary
+
+
+def decode_semantic(decoder, subtype, shareable_index=None):
+    # Major tag 6
+    tagnum = decode_uint(decoder, subtype)
+
+    # Special handling for the "shareable" tag
+    if tagnum == 28:
+        shareable_index = decoder._allocate_shareable()
+        return decoder.decode(shareable_index)
+
+    value = decoder.decode()
+    semantic_decoder = semantic_decoders.get(tagnum)
+    if semantic_decoder:
+        return semantic_decoder(decoder, value, shareable_index)
+
+    tag = CBORTag(tagnum, value)
+    if decoder.tag_hook:
+        return decoder.tag_hook(decoder, tag, shareable_index)
+    else:
+        return tag
+
+
+def decode_special(decoder, subtype, shareable_index=None):
+    # Simple value
+    if subtype < 20:
+        return CBORSimpleValue(subtype)
+
+    # Major tag 7
+    return special_decoders[subtype](decoder)
+
+
+#
+# Semantic decoders (major tag 6)
+#
+
+def decode_datetime_string(decoder, value, shareable_index=None):
+    # Semantic tag 0
+    match = timestamp_re.match(value)
+    if match:
+        year, month, day, hour, minute, second, micro, offset_h, offset_m = match.groups()
+        if offset_h:
+            tz = timezone(timedelta(hours=int(offset_h), minutes=int(offset_m)))
+        else:
+            tz = timezone.utc
+
+        return datetime(int(year), int(month), int(day), int(hour), int(minute), int(second),
+                        int(micro or 0), tz)
+    else:
+        raise CBORDecodeError('invalid datetime string: {}'.format(value))
+
+
+def decode_epoch_datetime(decoder, value, shareable_index=None):
+    # Semantic tag 1
+    return datetime.fromtimestamp(value, timezone.utc)
+
+
+def decode_positive_bignum(decoder, value, shareable_index=None):
+    # Semantic tag 2
+    from binascii import hexlify
+    return int(hexlify(value), 16)
+
+
+def decode_negative_bignum(decoder, value, shareable_index=None):
+    # Semantic tag 3
+    return -decode_positive_bignum(decoder, value) - 1
+
+
+def decode_fraction(decoder, value, shareable_index=None):
+    # Semantic tag 4
+    from decimal import Decimal
+    exp = Decimal(value[0])
+    mantissa = Decimal(value[1])
+    return mantissa * (10 ** exp)
+
+
+def decode_bigfloat(decoder, value, shareable_index=None):
+    # Semantic tag 5
+    from decimal import Decimal
+    exp = Decimal(value[0])
+    mantissa = Decimal(value[1])
+    return mantissa * (2 ** exp)
+
+
+def decode_sharedref(decoder, value, shareable_index=None):
+    # Semantic tag 29
+    try:
+        shared = decoder._shareables[value]
+    except IndexError:
+        raise CBORDecodeError('shared reference %d not found' % value)
+
+    if shared is None:
+        raise CBORDecodeError('shared value %d has not been initialized' % value)
+    else:
+        return shared
+
+
+def decode_rational(decoder, value, shareable_index=None):
+    # Semantic tag 30
+    from fractions import Fraction
+    return Fraction(*value)
+
+
+def decode_regexp(decoder, value, shareable_index=None):
+    # Semantic tag 35
+    return re.compile(value)
+
+
+def decode_mime(decoder, value, shareable_index=None):
+    # Semantic tag 36
+    from email.parser import Parser
+    return Parser().parsestr(value)
+
+
+def decode_uuid(decoder, value, shareable_index=None):
+    # Semantic tag 37
+    from uuid import UUID
+    return UUID(bytes=value)
+
+
+def decode_set(decoder, value, shareable_index=None):
+    # Semantic tag 258
+    return set(value)
+
+
+#
+# Special decoders (major tag 7)
+#
+
+def decode_simple_value(decoder, shareable_index=None):
+    return CBORSimpleValue(struct.unpack('>B', decoder.read(1))[0])
+
+
+def decode_float16(decoder, shareable_index=None):
+    payload = decoder.read(2)
+    return unpack_float16(payload)
+
+
+def decode_float32(decoder, shareable_index=None):
+    return struct.unpack('>f', decoder.read(4))[0]
+
+
+def decode_float64(decoder, shareable_index=None):
+    return struct.unpack('>d', decoder.read(8))[0]
+
+
+major_decoders = {
+    0: decode_uint,
+    1: decode_negint,
+    2: decode_bytestring,
+    3: decode_string,
+    4: decode_array,
+    5: decode_map,
+    6: decode_semantic,
+    7: decode_special
+}
+
+special_decoders = {
+    20: lambda self: False,
+    21: lambda self: True,
+    22: lambda self: None,
+    23: lambda self: undefined,
+    24: decode_simple_value,
+    25: decode_float16,
+    26: decode_float32,
+    27: decode_float64,
+    31: lambda self: break_marker
+}
+
+semantic_decoders = {
+    0: decode_datetime_string,
+    1: decode_epoch_datetime,
+    2: decode_positive_bignum,
+    3: decode_negative_bignum,
+    4: decode_fraction,
+    5: decode_bigfloat,
+    29: decode_sharedref,
+    30: decode_rational,
+    35: decode_regexp,
+    36: decode_mime,
+    37: decode_uuid,
+    258: decode_set
+}
+
+
+class CBORDecoder(object):
+    """
+    Deserializes a CBOR encoded byte stream.
+
+    :param tag_hook: Callable that takes 3 arguments: the decoder instance, the
+        :class:`~cbor2.types.CBORTag` and the shareable index for the resulting object, if any.
+        This callback is called for any tags for which there is no built-in decoder.
+        The return value is substituted for the CBORTag object in the deserialized output.
+    :param object_hook: Callable that takes 2 arguments: the decoder instance and the dictionary.
+        This callback is called for each deserialized :class:`dict` object.
+        The return value is substituted for the dict in the deserialized output.
+    """
+
+    __slots__ = ('fp', 'tag_hook', 'object_hook', '_shareables')
+
+    def __init__(self, fp, tag_hook=None, object_hook=None):
+        self.fp = fp
+        self.tag_hook = tag_hook
+        self.object_hook = object_hook
+        self._shareables = []
+
+    def _allocate_shareable(self):
+        self._shareables.append(None)
+        return len(self._shareables) - 1
+
+    def set_shareable(self, index, value):
+        """
+        Set the shareable value for the last encountered shared value marker, if any.
+
+        If the given index is ``None``, nothing is done.
+
+        :param index: the value of the ``shared_index`` argument to the decoder
+        :param value: the shared value
+
+        """
+        if index is not None:
+            self._shareables[index] = value
+
+    def read(self, amount):
+        """
+        Read bytes from the data stream.
+
+        :param int amount: the number of bytes to read
+
+        """
+        data = self.fp.read(amount)
+        if len(data) < amount:
+            raise CBORDecodeError('premature end of stream (expected to read {} bytes, got {} '
+                                  'instead)'.format(amount, len(data)))
+
+        return data
+
+    def decode(self, shareable_index=None):
+        """
+        Decode the next value from the stream.
+
+        :raises CBORDecodeError: if there is any problem decoding the stream
+
+        """
+        try:
+            initial_byte = byte_as_integer(self.fp.read(1))
+            major_type = initial_byte >> 5
+            subtype = initial_byte & 31
+        except Exception as e:
+            raise CBORDecodeError('error reading major type at index {}: {}'
+                                  .format(self.fp.tell(), e))
+
+        decoder = major_decoders[major_type]
+        try:
+            return decoder(self, subtype, shareable_index)
+        except CBORDecodeError:
+            raise
+        except Exception as e:
+            raise CBORDecodeError('error decoding value at index {}: {}'.format(self.fp.tell(), e))
+
+    def decode_from_bytes(self, buf):
+        """
+        Wrap the given bytestring as a file and call :meth:`decode` with it as the argument.
+
+        This method was intended to be used from the ``tag_hook`` hook when an object needs to be
+        decoded separately from the rest but while still taking advantage of the shared value
+        registry.
+
+        """
+        old_fp = self.fp
+        self.fp = BytesIO(buf)
+        retval = self.decode()
+        self.fp = old_fp
+        return retval
+
+
+def loads(payload, **kwargs):
+    """
+    Deserialize an object from a bytestring.
+
+    :param bytes payload: the bytestring to serialize
+    :param kwargs: keyword arguments passed to :class:`~.CBORDecoder`
+    :return: the deserialized object
+
+    """
+    fp = BytesIO(payload)
+    return CBORDecoder(fp, **kwargs).decode()
+
+
+def load(fp, **kwargs):
+    """
+    Deserialize an object from an open file.
+
+    :param fp: the input file (any file-like object)
+    :param kwargs: keyword arguments passed to :class:`~.CBORDecoder`
+    :return: the deserialized object
+
+    """
+    return CBORDecoder(fp, **kwargs).decode()
diff --git a/mercurial/thirdparty/cbor/cbor2/encoder.py b/mercurial/thirdparty/cbor/cbor2/encoder.py
new file mode 100644
--- /dev/null
+++ b/mercurial/thirdparty/cbor/cbor2/encoder.py
@@ -0,0 +1,425 @@
+import re
+import struct
+from collections import OrderedDict, defaultdict
+from contextlib import contextmanager
+from functools import wraps
+from datetime import datetime, date, time
+from io import BytesIO
+
+from .compat import (
+    iteritems, timezone, long, unicode, as_unicode, bytes_from_list, pack_float16, unpack_float16)
+from .types import CBORTag, undefined, CBORSimpleValue
+
+
+class CBOREncodeError(Exception):
+    """Raised when an error occurs while serializing an object into a CBOR datastream."""
+
+
+def shareable_encoder(func):
+    """
+    Wrap the given encoder function to gracefully handle cyclic data structures.
+
+    If value sharing is enabled, this marks the given value shared in the datastream on the
+    first call. If the value has already been passed to this method, a reference marker is
+    instead written to the data stream and the wrapped function is not called.
+
+    If value sharing is disabled, only infinite recursion protection is done.
+
+    """
+    @wraps(func)
+    def wrapper(encoder, value, *args, **kwargs):
+        value_id = id(value)
+        container, container_index = encoder._shared_containers.get(value_id, (None, None))
+        if encoder.value_sharing:
+            if container is value:
+                # Generate a reference to the previous index instead of encoding this again
+                encoder.write(encode_length(0xd8, 0x1d))
+                encode_int(encoder, container_index)
+            else:
+                # Mark the container as shareable
+                encoder._shared_containers[value_id] = (value, len(encoder._shared_containers))
+                encoder.write(encode_length(0xd8, 0x1c))
+                func(encoder, value, *args, **kwargs)
+        else:
+            if container is value:
+                raise CBOREncodeError('cyclic data structure detected but value sharing is '
+                                      'disabled')
+            else:
+                encoder._shared_containers[value_id] = (value, None)
+                func(encoder, value, *args, **kwargs)
+                del encoder._shared_containers[value_id]
+
+    return wrapper
+
+
+def encode_length(major_tag, length):
+    if length < 24:
+        return struct.pack('>B', major_tag | length)
+    elif length < 256:
+        return struct.pack('>BB', major_tag | 24, length)
+    elif length < 65536:
+        return struct.pack('>BH', major_tag | 25, length)
+    elif length < 4294967296:
+        return struct.pack('>BL', major_tag | 26, length)
+    else:
+        return struct.pack('>BQ', major_tag | 27, length)
+
+
+def encode_int(encoder, value):
+    # Big integers (2 ** 64 and over)
+    if value >= 18446744073709551616 or value < -18446744073709551616:
+        if value >= 0:
+            major_type = 0x02
+        else:
+            major_type = 0x03
+            value = -value - 1
+
+        values = []
+        while value > 0:
+            value, remainder = divmod(value, 256)
+            values.insert(0, remainder)
+
+        payload = bytes_from_list(values)
+        encode_semantic(encoder, CBORTag(major_type, payload))
+    elif value >= 0:
+        encoder.write(encode_length(0, value))
+    else:
+        encoder.write(encode_length(0x20, abs(value) - 1))
+
+
+def encode_bytestring(encoder, value):
+    encoder.write(encode_length(0x40, len(value)) + value)
+
+
+def encode_bytearray(encoder, value):
+    encode_bytestring(encoder, bytes(value))
+
+
+def encode_string(encoder, value):
+    encoded = value.encode('utf-8')
+    encoder.write(encode_length(0x60, len(encoded)) + encoded)
+
+
+@shareable_encoder
+def encode_array(encoder, value):
+    encoder.write(encode_length(0x80, len(value)))
+    for item in value:
+        encoder.encode(item)
+
+
+@shareable_encoder
+def encode_map(encoder, value):
+    encoder.write(encode_length(0xa0, len(value)))
+    for key, val in iteritems(value):
+        encoder.encode(key)
+        encoder.encode(val)
+
+
+def encode_sortable_key(encoder, value):
+    """Takes a key and calculates the length of its optimal byte representation"""
+    encoded = encoder.encode_to_bytes(value)
+    return len(encoded), encoded
+
+
+@shareable_encoder
+def encode_canonical_map(encoder, value):
+    """Reorder keys according to Canonical CBOR specification"""
+    keyed_keys = ((encode_sortable_key(encoder, key), key) for key in value.keys())
+    encoder.write(encode_length(0xa0, len(value)))
+    for sortkey, realkey in sorted(keyed_keys):
+        encoder.write(sortkey[1])
+        encoder.encode(value[realkey])
+
+
+def encode_semantic(encoder, value):
+    encoder.write(encode_length(0xc0, value.tag))
+    encoder.encode(value.value)
+
+
+#
+# Semantic decoders (major tag 6)
+#
+
+def encode_datetime(encoder, value):
+    # Semantic tag 0
+    if not value.tzinfo:
+        if encoder.timezone:
+            value = value.replace(tzinfo=encoder.timezone)
+        else:
+            raise CBOREncodeError(
+                'naive datetime encountered and no default timezone has been set')
+
+    if encoder.datetime_as_timestamp:
+        from calendar import timegm
+        timestamp = timegm(value.utctimetuple()) + value.microsecond // 1000000
+        encode_semantic(encoder, CBORTag(1, timestamp))
+    else:
+        datestring = as_unicode(value.isoformat().replace('+00:00', 'Z'))
+        encode_semantic(encoder, CBORTag(0, datestring))
+
+
+def encode_date(encoder, value):
+    value = datetime.combine(value, time()).replace(tzinfo=timezone.utc)
+    encode_datetime(encoder, value)
+
+
+def encode_decimal(encoder, value):
+    # Semantic tag 4
+    if value.is_nan():
+        encoder.write(b'\xf9\x7e\x00')
+    elif value.is_infinite():
+        encoder.write(b'\xf9\x7c\x00' if value > 0 else b'\xf9\xfc\x00')
+    else:
+        dt = value.as_tuple()
+        mantissa = sum(d * 10 ** i for i, d in enumerate(reversed(dt.digits)))
+        with encoder.disable_value_sharing():
+            encode_semantic(encoder, CBORTag(4, [dt.exponent, mantissa]))
+
+
+def encode_rational(encoder, value):
+    # Semantic tag 30
+    with encoder.disable_value_sharing():
+        encode_semantic(encoder, CBORTag(30, [value.numerator, value.denominator]))
+
+
+def encode_regexp(encoder, value):
+    # Semantic tag 35
+    encode_semantic(encoder, CBORTag(35, as_unicode(value.pattern)))
+
+
+def encode_mime(encoder, value):
+    # Semantic tag 36
+    encode_semantic(encoder, CBORTag(36, as_unicode(value.as_string())))
+
+
+def encode_uuid(encoder, value):
+    # Semantic tag 37
+    encode_semantic(encoder, CBORTag(37, value.bytes))
+
+
+def encode_set(encoder, value):
+    # Semantic tag 258
+    encode_semantic(encoder, CBORTag(258, tuple(value)))
+
+
+def encode_canonical_set(encoder, value):
+    # Semantic tag 258
+    values = sorted([(encode_sortable_key(encoder, key), key) for key in value])
+    encode_semantic(encoder, CBORTag(258, [key[1] for key in values]))
+
+
+#
+# Special encoders (major tag 7)
+#
+
+def encode_simple_value(encoder, value):
+    if value.value < 20:
+        encoder.write(struct.pack('>B', 0xe0 | value.value))
+    else:
+        encoder.write(struct.pack('>BB', 0xf8, value.value))
+
+
+def encode_float(encoder, value):
+    # Handle special values efficiently
+    import math
+    if math.isnan(value):
+        encoder.write(b'\xf9\x7e\x00')
+    elif math.isinf(value):
+        encoder.write(b'\xf9\x7c\x00' if value > 0 else b'\xf9\xfc\x00')
+    else:
+        encoder.write(struct.pack('>Bd', 0xfb, value))
+
+
+def encode_minimal_float(encoder, value):
+    # Handle special values efficiently
+    import math
+    if math.isnan(value):
+        encoder.write(b'\xf9\x7e\x00')
+    elif math.isinf(value):
+        encoder.write(b'\xf9\x7c\x00' if value > 0 else b'\xf9\xfc\x00')
+    else:
+        encoded = struct.pack('>Bf', 0xfa, value)
+        if struct.unpack('>Bf', encoded)[1] != value:
+            encoded = struct.pack('>Bd', 0xfb, value)
+            encoder.write(encoded)
+        else:
+            f16 = pack_float16(value)
+            if f16 and unpack_float16(f16[1:]) == value:
+                encoder.write(f16)
+            else:
+                encoder.write(encoded)
+
+
+def encode_boolean(encoder, value):
+    encoder.write(b'\xf5' if value else b'\xf4')
+
+
+def encode_none(encoder, value):
+    encoder.write(b'\xf6')
+
+
+def encode_undefined(encoder, value):
+    encoder.write(b'\xf7')
+
+
+default_encoders = OrderedDict([
+    (bytes, encode_bytestring),
+    (bytearray, encode_bytearray),
+    (unicode, encode_string),
+    (int, encode_int),
+    (long, encode_int),
+    (float, encode_float),
+    (('decimal', 'Decimal'), encode_decimal),
+    (bool, encode_boolean),
+    (type(None), encode_none),
+    (tuple, encode_array),
+    (list, encode_array),
+    (dict, encode_map),
+    (defaultdict, encode_map),
+    (OrderedDict, encode_map),
+    (type(undefined), encode_undefined),
+    (datetime, encode_datetime),
+    (date, encode_date),
+    (type(re.compile('')), encode_regexp),
+    (('fractions', 'Fraction'), encode_rational),
+    (('email.message', 'Message'), encode_mime),
+    (('uuid', 'UUID'), encode_uuid),
+    (CBORSimpleValue, encode_simple_value),
+    (CBORTag, encode_semantic),
+    (set, encode_set),
+    (frozenset, encode_set)
+])
+
+canonical_encoders = OrderedDict([
+    (float, encode_minimal_float),
+    (dict, encode_canonical_map),
+    (defaultdict, encode_canonical_map),
+    (OrderedDict, encode_canonical_map),
+    (set, encode_canonical_set),
+    (frozenset, encode_canonical_set)
+])
+
+
+class CBOREncoder(object):
+    """
+    Serializes objects to a byte stream using Concise Binary Object Representation.
+
+    :param datetime_as_timestamp: set to ``True`` to serialize datetimes as UNIX timestamps
+        (this makes datetimes more concise on the wire but loses the time zone information)
+    :param datetime.tzinfo timezone: the default timezone to use for serializing naive datetimes
+    :param value_sharing: if ``True``, allows more efficient serializing of repeated values and,
+        more importantly, cyclic data structures, at the cost of extra line overhead
+    :param default: a callable that is called by the encoder with three arguments
+        (encoder, value, file object) when no suitable encoder has been found, and should use the
+        methods on the encoder to encode any objects it wants to add to the data stream
+    :param canonical: Forces mapping types to be output in a stable order to guarantee that the
+        output will always produce the same hash given the same input.
+    """
+
+    __slots__ = ('fp', 'datetime_as_timestamp', 'timezone', 'default', 'value_sharing',
+                 'json_compatible', '_shared_containers', '_encoders')
+
+    def __init__(self, fp, datetime_as_timestamp=False, timezone=None, value_sharing=False,
+                 default=None, canonical=False):
+        self.fp = fp
+        self.datetime_as_timestamp = datetime_as_timestamp
+        self.timezone = timezone
+        self.value_sharing = value_sharing
+        self.default = default
+        self._shared_containers = {}  # indexes used for value sharing
+        self._encoders = default_encoders.copy()
+        if canonical:
+            self._encoders.update(canonical_encoders)
+
+    def _find_encoder(self, obj_type):
+        from sys import modules
+
+        for type_, enc in list(iteritems(self._encoders)):
+            if type(type_) is tuple:
+                modname, typename = type_
+                imported_type = getattr(modules.get(modname), typename, None)
+                if imported_type is not None:
+                    del self._encoders[type_]
+                    self._encoders[imported_type] = enc
+                    type_ = imported_type
+                else:  # pragma: nocover
+                    continue
+
+            if issubclass(obj_type, type_):
+                self._encoders[obj_type] = enc
+                return enc
+
+        return None
+
+    @contextmanager
+    def disable_value_sharing(self):
+        """Disable value sharing in the encoder for the duration of the context block."""
+        old_value_sharing = self.value_sharing
+        self.value_sharing = False
+        yield
+        self.value_sharing = old_value_sharing
+
+    def write(self, data):
+        """
+        Write bytes to the data stream.
+
+        :param data: the bytes to write
+
+        """
+        self.fp.write(data)
+
+    def encode(self, obj):
+        """
+        Encode the given object using CBOR.
+
+        :param obj: the object to encode
+
+        """
+        obj_type = obj.__class__
+        encoder = self._encoders.get(obj_type) or self._find_encoder(obj_type) or self.default
+        if not encoder:
+            raise CBOREncodeError('cannot serialize type %s' % obj_type.__name__)
+
+        encoder(self, obj)
+
+    def encode_to_bytes(self, obj):
+        """
+        Encode the given object to a byte buffer and return its value as bytes.
+
+        This method was intended to be used from the ``default`` hook when an object needs to be
+        encoded separately from the rest but while still taking advantage of the shared value
+        registry.
+
+        """
+        old_fp = self.fp
+        self.fp = fp = BytesIO()
+        self.encode(obj)
+        self.fp = old_fp
+        return fp.getvalue()
+
+
+def dumps(obj, **kwargs):
+    """
+    Serialize an object to a bytestring.
+
+    :param obj: the object to serialize
+    :param kwargs: keyword arguments passed to :class:`~.CBOREncoder`
+    :return: the serialized output
+    :rtype: bytes
+
+    """
+    fp = BytesIO()
+    dump(obj, fp, **kwargs)
+    return fp.getvalue()
+
+
+def dump(obj, fp, **kwargs):
+    """
+    Serialize an object to a file.
+
+    :param obj: the object to serialize
+    :param fp: a file-like object
+    :param kwargs: keyword arguments passed to :class:`~.CBOREncoder`
+
+    """
+    CBOREncoder(fp, **kwargs).encode(obj)
diff --git a/mercurial/thirdparty/cbor/cbor2/types.py b/mercurial/thirdparty/cbor/cbor2/types.py
new file mode 100644
--- /dev/null
+++ b/mercurial/thirdparty/cbor/cbor2/types.py
@@ -0,0 +1,55 @@
+class CBORTag(object):
+    """
+    Represents a CBOR semantic tag.
+
+    :param int tag: tag number
+    :param value: encapsulated value (any object)
+    """
+
+    __slots__ = 'tag', 'value'
+
+    def __init__(self, tag, value):
+        self.tag = tag
+        self.value = value
+
+    def __eq__(self, other):
+        if isinstance(other, CBORTag):
+            return self.tag == other.tag and self.value == other.value
+        return NotImplemented
+
+    def __repr__(self):
+        return 'CBORTag({self.tag}, {self.value!r})'.format(self=self)
+
+
+class CBORSimpleValue(object):
+    """
+    Represents a CBOR "simple value".
+
+    :param int value: the value (0-255)
+    """
+
+    __slots__ = 'value'
+
+    def __init__(self, value):
+        if value < 0 or value > 255:
+            raise TypeError('simple value too big')
+        self.value = value
+
+    def __eq__(self, other):
+        if isinstance(other, CBORSimpleValue):
+            return self.value == other.value
+        elif isinstance(other, int):
+            return self.value == other
+        return NotImplemented
+
+    def __repr__(self):
+        return 'CBORSimpleValue({self.value})'.format(self=self)
+
+
+class UndefinedType(object):
+    __slots__ = ()
+
+
+#: Represents the "undefined" value.
+undefined = UndefinedType()
+break_marker = object()