gistfile1.txt

def _element_to_bson(key, value, check_keys):
    if not isinstance(key, basestring):
        raise InvalidDocument("documents must have only string keys, "
                              "key was %r" % key)

    if check_keys:
        if key.startswith("$"):
            raise InvalidDocument("key %r must not start with '$'" % key)
        if "." in key:
            raise InvalidDocument("key %r must not contain '.'" % key)

    name = _make_c_string(key, True)
    if isinstance(value, float):
        return "\x01" + name + struct.pack("<d", value)

    # Use Binary w/ subtype 3 for UUID instances
    try:
        import uuid

        if isinstance(value, uuid.UUID):
            value = Binary(value.bytes, subtype=3)
    except ImportError:
        pass

    if isinstance(value, Binary):
        subtype = value.subtype
        if subtype == 2:
            value = struct.pack("<i", len(value)) + value
        return "\x05%s%s%s%s" % (name, struct.pack("<i", len(value)),
                                 chr(subtype), value)
    if isinstance(value, Code):
        cstring = _make_c_string(value)
        scope = _dict_to_bson(value.scope, False, False)
        full_length = struct.pack("<i", 8 + len(cstring) + len(scope))
        length = struct.pack("<i", len(cstring))
        return "\x0F" + name + full_length + length + cstring + scope
    if isinstance(value, str):
        cstring = _make_c_string(value)
        length = struct.pack("<i", len(cstring))
        return "\x02" + name + length + cstring
    if isinstance(value, unicode):
        cstring = _make_c_string(value)
        length = struct.pack("<i", len(cstring))
        return "\x02" + name + length + cstring
    if isinstance(value, dict):
        return "\x03" + name + _dict_to_bson(value, check_keys, False)
    if isinstance(value, (list, tuple)):
        as_dict = SON(zip([str(i) for i in range(len(value))], value))
        return "\x04" + name + _dict_to_bson(as_dict, check_keys, False)
    if isinstance(value, ObjectId):
        return "\x07" + name + value.binary
    if value is True:
        return "\x08" + name + "\x01"
    if value is False:
        return "\x08" + name + "\x00"
    if isinstance(value, (int, long)):
        # TODO this is a really ugly way to check for this...
        if value > 2 ** 64 / 2 - 1 or value < -2 ** 64 / 2:
            raise OverflowError("BSON can only handle up to 8-byte ints")
        if value > 2 ** 32 / 2 - 1 or value < -2 ** 32 / 2:
            return "\x12" + name + struct.pack("<q", value)
        return "\x10" + name + struct.pack("<i", value)
    if isinstance(value, datetime.datetime):
        if value.utcoffset() is not None:
            value = value - value.utcoffset()
        millis = int(calendar.timegm(value.timetuple()) * 1000 +
                     value.microsecond / 1000)
        return "\x09" + name + struct.pack("<q", millis)
    if isinstance(value, Timestamp):
        time = struct.pack("<I", value.time)
        inc = struct.pack("<I", value.inc)
        return "\x11" + name + inc + time
    if value is None:
        return "\x0A" + name
    if isinstance(value, RE_TYPE):
        pattern = value.pattern
        flags = ""
        if value.flags & re.IGNORECASE:
            flags += "i"
        if value.flags & re.LOCALE:
            flags += "l"
        if value.flags & re.MULTILINE:
            flags += "m"
        if value.flags & re.DOTALL:
            flags += "s"
        if value.flags & re.UNICODE:
            flags += "u"
        if value.flags & re.VERBOSE:
            flags += "x"
        return "\x0B" + name + _make_c_string(pattern, True) + \
            _make_c_string(flags)
    if isinstance(value, DBRef):
        return _element_to_bson(key, value.as_doc(), False)
    if isinstance(value, MinKey):
        return "\xFF" + name
    if isinstance(value, MaxKey):
        return "\x7F" + name

    raise InvalidDocument("cannot convert value of type %s to bson" %
                          type(value))