Application: gvSIG desktop » gvSIG scripting

"""Implementation of JSONEncoder

"""

from __future__ import absolute_import

import re

from operator import itemgetter

from decimal import Decimal

from .compat import u, unichr, binary_type, string_types, integer_types, PY3

def _import_speedups():

    try:

        from . import _speedups

        return _speedups.encode_basestring_ascii, _speedups.make_encoder

    except ImportError:

        return None, None

c_encode_basestring_ascii, c_make_encoder = _import_speedups()

from simplejson.decoder import PosInf

#ESCAPE = re.compile(ur'[\x00-\x1f\\"\b\f\n\r\t\u2028\u2029]')

# This is required because u() will mangle the string and ur'' isn't valid

# python3 syntax

ESCAPE = re.compile(u'[\\x00-\\x1f\\\\"\\b\\f\\n\\r\\t\u2028\u2029]')

ESCAPE_ASCII = re.compile(r'([\\"]|[^\ -~])')

HAS_UTF8 = re.compile(r'[\x80-\xff]')

ESCAPE_DCT = {

    '\\': '\\\\',

    '"': '\\"',

    '\b': '\\b',

    '\f': '\\f',

    '\n': '\\n',

    '\r': '\\r',

    '\t': '\\t',

}

for i in range(0x20):

    #ESCAPE_DCT.setdefault(chr(i), '\\u{0:04x}'.format(i))

    ESCAPE_DCT.setdefault(chr(i), '\\u%04x' % (i,))

for i in [0x2028, 0x2029]:

    ESCAPE_DCT.setdefault(unichr(i), '\\u%04x' % (i,))

FLOAT_REPR = repr

def encode_basestring(s, _PY3=PY3, _q=u('"')):

    """Return a JSON representation of a Python string

    """

    if _PY3:

        if isinstance(s, binary_type):

            s = s.decode('utf-8')

    else:

        if isinstance(s, str) and HAS_UTF8.search(s) is not None:

            s = s.decode('utf-8')

    def replace(match):

        return ESCAPE_DCT[match.group(0)]

    return _q + ESCAPE.sub(replace, s) + _q

def py_encode_basestring_ascii(s, _PY3=PY3):

    """Return an ASCII-only JSON representation of a Python string

    """

    if _PY3:

        if isinstance(s, binary_type):

            s = s.decode('utf-8')

    else:

        if isinstance(s, str) and HAS_UTF8.search(s) is not None:

            s = s.decode('utf-8')

    def replace(match):

        s = match.group(0)

        try:

            return ESCAPE_DCT[s]

        except KeyError:

            n = ord(s)

            if n < 0x10000:

                #return '\\u{0:04x}'.format(n)

                return '\\u%04x' % (n,)

            else:

                # surrogate pair

                n -= 0x10000

                s1 = 0xd800 | ((n >> 10) & 0x3ff)

                s2 = 0xdc00 | (n & 0x3ff)

                #return '\\u{0:04x}\\u{1:04x}'.format(s1, s2)

                return '\\u%04x\\u%04x' % (s1, s2)

    return '"' + str(ESCAPE_ASCII.sub(replace, s)) + '"'

encode_basestring_ascii = (

    c_encode_basestring_ascii or py_encode_basestring_ascii)

class JSONEncoder(object):

    """Extensible JSON <http://json.org> encoder for Python data structures.

    Supports the following objects and types by default:

    +-------------------+---------------+

    | Python            | JSON          |

    +===================+===============+

    | dict, namedtuple  | object        |

    +-------------------+---------------+

    | list, tuple       | array         |

    +-------------------+---------------+

    | str, unicode      | string        |

    +-------------------+---------------+

    | int, long, float  | number        |

    +-------------------+---------------+

    | True              | true          |

    +-------------------+---------------+

    | False             | false         |

    +-------------------+---------------+

    | None              | null          |

    +-------------------+---------------+

    To extend this to recognize other objects, subclass and implement a

    ``.default()`` method with another method that returns a serializable

    object for ``o`` if possible, otherwise it should call the superclass

    implementation (to raise ``TypeError``).

    """

    item_separator = ', '

    key_separator = ': '

    def __init__(self, skipkeys=False, ensure_ascii=True,

                 check_circular=True, allow_nan=True, sort_keys=False,

                 indent=None, separators=None, encoding='utf-8', default=None,

                 use_decimal=True, namedtuple_as_object=True,

                 tuple_as_array=True, bigint_as_string=False,

                 item_sort_key=None, for_json=False, ignore_nan=False,

                 int_as_string_bitcount=None):

        """Constructor for JSONEncoder, with sensible defaults.

        If skipkeys is false, then it is a TypeError to attempt

        encoding of keys that are not str, int, long, float or None.  If

        skipkeys is True, such items are simply skipped.

        If ensure_ascii is true, the output is guaranteed to be str

        objects with all incoming unicode characters escaped.  If

        ensure_ascii is false, the output will be unicode object.

        If check_circular is true, then lists, dicts, and custom encoded

        objects will be checked for circular references during encoding to

        prevent an infinite recursion (which would cause an OverflowError).

        Otherwise, no such check takes place.

        If allow_nan is true, then NaN, Infinity, and -Infinity will be

        encoded as such.  This behavior is not JSON specification compliant,

        but is consistent with most JavaScript based encoders and decoders.

        Otherwise, it will be a ValueError to encode such floats.

        If sort_keys is true, then the output of dictionaries will be

        sorted by key; this is useful for regression tests to ensure

        that JSON serializations can be compared on a day-to-day basis.

        If indent is a string, then JSON array elements and object members

        will be pretty-printed with a newline followed by that string repeated

        for each level of nesting. ``None`` (the default) selects the most compact

        representation without any newlines. For backwards compatibility with

        versions of simplejson earlier than 2.1.0, an integer is also accepted

        and is converted to a string with that many spaces.

        If specified, separators should be an (item_separator, key_separator)

        tuple.  The default is (', ', ': ') if *indent* is ``None`` and

        (',', ': ') otherwise.  To get the most compact JSON representation,

        you should specify (',', ':') to eliminate whitespace.

        If specified, default is a function that gets called for objects

        that can't otherwise be serialized.  It should return a JSON encodable

        version of the object or raise a ``TypeError``.

        If encoding is not None, then all input strings will be

        transformed into unicode using that encoding prior to JSON-encoding.

        The default is UTF-8.

        If use_decimal is true (not the default), ``decimal.Decimal`` will

        be supported directly by the encoder. For the inverse, decode JSON

        with ``parse_float=decimal.Decimal``.

        If namedtuple_as_object is true (the default), objects with

        ``_asdict()`` methods will be encoded as JSON objects.

        If tuple_as_array is true (the default), tuple (and subclasses) will

        be encoded as JSON arrays.

        If bigint_as_string is true (not the default), ints 2**53 and higher

        or lower than -2**53 will be encoded as strings. This is to avoid the

        rounding that happens in Javascript otherwise.

        If int_as_string_bitcount is a positive number (n), then int of size

        greater than or equal to 2**n or lower than or equal to -2**n will be

        encoded as strings.

        If specified, item_sort_key is a callable used to sort the items in

        each dictionary. This is useful if you want to sort items other than

        in alphabetical order by key.

        If for_json is true (not the default), objects with a ``for_json()``

        method will use the return value of that method for encoding as JSON

        instead of the object.

        If *ignore_nan* is true (default: ``False``), then out of range

        :class:`float` values (``nan``, ``inf``, ``-inf``) will be serialized

        as ``null`` in compliance with the ECMA-262 specification. If true,

        this will override *allow_nan*.

        """

        self.skipkeys = skipkeys

        self.ensure_ascii = ensure_ascii

        self.check_circular = check_circular

        self.allow_nan = allow_nan

        self.sort_keys = sort_keys

        self.use_decimal = use_decimal

        self.namedtuple_as_object = namedtuple_as_object

        self.tuple_as_array = tuple_as_array

        self.bigint_as_string = bigint_as_string

        self.item_sort_key = item_sort_key

        self.for_json = for_json

        self.ignore_nan = ignore_nan

        self.int_as_string_bitcount = int_as_string_bitcount

        if indent is not None and not isinstance(indent, string_types):

            indent = indent * ' '

        self.indent = indent

        if separators is not None:

            self.item_separator, self.key_separator = separators

        elif indent is not None:

            self.item_separator = ','

        if default is not None:

            self.default = default

        self.encoding = encoding

    def default(self, o):

        """Implement this method in a subclass such that it returns

        a serializable object for ``o``, or calls the base implementation

        (to raise a ``TypeError``).

        For example, to support arbitrary iterators, you could

        implement default like this::

            def default(self, o):

                try:

                    iterable = iter(o)

                except TypeError:

                    pass

                else:

                    return list(iterable)

                return JSONEncoder.default(self, o)

        """

        raise TypeError(repr(o) + " is not JSON serializable")

    def encode(self, o):

        """Return a JSON string representation of a Python data structure.

        >>> from simplejson import JSONEncoder

        >>> JSONEncoder().encode({"foo": ["bar", "baz"]})

        '{"foo": ["bar", "baz"]}'

        """

        # This is for extremely simple cases and benchmarks.

        if isinstance(o, binary_type):

            _encoding = self.encoding

            if (_encoding is not None and not (_encoding == 'utf-8')):

                o = o.decode(_encoding)

        if isinstance(o, string_types):

            if self.ensure_ascii:

                return encode_basestring_ascii(o)

            else:

                return encode_basestring(o)

        # This doesn't pass the iterator directly to ''.join() because the

        # exceptions aren't as detailed.  The list call should be roughly

        # equivalent to the PySequence_Fast that ''.join() would do.

        chunks = self.iterencode(o, _one_shot=True)

        if not isinstance(chunks, (list, tuple)):

            chunks = list(chunks)

        if self.ensure_ascii:

            return ''.join(chunks)

        else:

            return u''.join(chunks)

    def iterencode(self, o, _one_shot=False):

        """Encode the given object and yield each string

        representation as available.

        For example::

            for chunk in JSONEncoder().iterencode(bigobject):

                mysocket.write(chunk)

        """

        if self.check_circular:

            markers = {}

        else:

            markers = None

        if self.ensure_ascii:

            _encoder = encode_basestring_ascii

        else:

            _encoder = encode_basestring

        if self.encoding != 'utf-8':

            def _encoder(o, _orig_encoder=_encoder, _encoding=self.encoding):

                if isinstance(o, binary_type):

                    o = o.decode(_encoding)

                return _orig_encoder(o)

        def floatstr(o, allow_nan=self.allow_nan, ignore_nan=self.ignore_nan,

                _repr=FLOAT_REPR, _inf=PosInf, _neginf=-PosInf):

            # Check for specials. Note that this type of test is processor

            # and/or platform-specific, so do tests which don't depend on

            # the internals.

            if o != o:

                text = 'NaN'

            elif o == _inf:

                text = 'Infinity'

            elif o == _neginf:

                text = '-Infinity'

            else:

                return _repr(o)

            if ignore_nan:

                text = 'null'

            elif not allow_nan:

                raise ValueError(

                    "Out of range float values are not JSON compliant: " +

                    repr(o))

            return text

        key_memo = {}

        int_as_string_bitcount = (

            53 if self.bigint_as_string else self.int_as_string_bitcount)

        if (_one_shot and c_make_encoder is not None

                and self.indent is None):

            _iterencode = c_make_encoder(

                markers, self.default, _encoder, self.indent,

                self.key_separator, self.item_separator, self.sort_keys,

                self.skipkeys, self.allow_nan, key_memo, self.use_decimal,

                self.namedtuple_as_object, self.tuple_as_array,

                int_as_string_bitcount,

                self.item_sort_key, self.encoding, self.for_json,

                self.ignore_nan, Decimal)

        else:

            _iterencode = _make_iterencode(

                markers, self.default, _encoder, self.indent, floatstr,

                self.key_separator, self.item_separator, self.sort_keys,

                self.skipkeys, _one_shot, self.use_decimal,

                self.namedtuple_as_object, self.tuple_as_array,

                int_as_string_bitcount,

                self.item_sort_key, self.encoding, self.for_json,

                Decimal=Decimal)

        try:

            return _iterencode(o, 0)

        finally:

            key_memo.clear()

class JSONEncoderForHTML(JSONEncoder):

    """An encoder that produces JSON safe to embed in HTML.

    To embed JSON content in, say, a script tag on a web page, the

    characters &, < and > should be escaped. They cannot be escaped

    with the usual entities (e.g. &) because they are not expanded

    within <script> tags.

    """

    def encode(self, o):

        # Override JSONEncoder.encode because it has hacks for

        # performance that make things more complicated.

        chunks = self.iterencode(o, True)

        if self.ensure_ascii:

            return ''.join(chunks)

        else:

            return u''.join(chunks)

    def iterencode(self, o, _one_shot=False):

        chunks = super(JSONEncoderForHTML, self).iterencode(o, _one_shot)

        for chunk in chunks:

            chunk = chunk.replace('&', '\\u0026')

            chunk = chunk.replace('<', '\\u003c')

            chunk = chunk.replace('>', '\\u003e')

            yield chunk

def _make_iterencode(markers, _default, _encoder, _indent, _floatstr,

        _key_separator, _item_separator, _sort_keys, _skipkeys, _one_shot,

        _use_decimal, _namedtuple_as_object, _tuple_as_array,

        _int_as_string_bitcount, _item_sort_key,

        _encoding,_for_json,

        ## HACK: hand-optimized bytecode; turn globals into locals

        _PY3=PY3,

        ValueError=ValueError,

        string_types=string_types,

        Decimal=Decimal,

        dict=dict,

        float=float,

        id=id,

        integer_types=integer_types,

        isinstance=isinstance,

        list=list,

        str=str,

        tuple=tuple,

    ):

    if _item_sort_key and not callable(_item_sort_key):

        raise TypeError("item_sort_key must be None or callable")

    elif _sort_keys and not _item_sort_key:

        _item_sort_key = itemgetter(0)

    if (_int_as_string_bitcount is not None and

        (_int_as_string_bitcount <= 0 or

         not isinstance(_int_as_string_bitcount, integer_types))):

        raise TypeError("int_as_string_bitcount must be a positive integer")

    def _encode_int(value):

        skip_quoting = (

            _int_as_string_bitcount is None

            or

            _int_as_string_bitcount < 1

        )

        if (

            skip_quoting or

            (-1 << _int_as_string_bitcount)

            < value <

            (1 << _int_as_string_bitcount)

        ):

            return str(value)

        return '"' + str(value) + '"'

    def _iterencode_list(lst, _current_indent_level):

        if not lst:

            yield '[]'

            return

        if markers is not None:

            markerid = id(lst)

            if markerid in markers:

                raise ValueError("Circular reference detected")

            markers[markerid] = lst

        buf = '['

        if _indent is not None:

            _current_indent_level += 1

            newline_indent = '\n' + (_indent * _current_indent_level)

            separator = _item_separator + newline_indent

            buf += newline_indent

        else:

            newline_indent = None

            separator = _item_separator

        first = True

        for value in lst:

            if first:

                first = False

            else:

                buf = separator

            if (isinstance(value, string_types) or

                (_PY3 and isinstance(value, binary_type))):

                yield buf + _encoder(value)

            elif value is None:

                yield buf + 'null'

            elif value is True:

                yield buf + 'true'

            elif value is False:

                yield buf + 'false'

            elif isinstance(value, integer_types):

                yield buf + _encode_int(value)

            elif isinstance(value, float):

                yield buf + _floatstr(value)

            elif _use_decimal and isinstance(value, Decimal):

                yield buf + str(value)

            else:

                yield buf

                for_json = _for_json and getattr(value, 'for_json', None)

                if for_json and callable(for_json):

                    chunks = _iterencode(for_json(), _current_indent_level)

                elif isinstance(value, list):

                    chunks = _iterencode_list(value, _current_indent_level)

                else:

                    _asdict = _namedtuple_as_object and getattr(value, '_asdict', None)

                    if _asdict and callable(_asdict):

                        chunks = _iterencode_dict(_asdict(),

                                                  _current_indent_level)

                    elif _tuple_as_array and isinstance(value, tuple):

                        chunks = _iterencode_list(value, _current_indent_level)

                    elif isinstance(value, dict):

                        chunks = _iterencode_dict(value, _current_indent_level)

                    else:

                        chunks = _iterencode(value, _current_indent_level)

                for chunk in chunks:

                    yield chunk

        if newline_indent is not None:

            _current_indent_level -= 1

            yield '\n' + (_indent * _current_indent_level)

        yield ']'

        if markers is not None:

            del markers[markerid]

    def _stringify_key(key):

        if isinstance(key, string_types): # pragma: no cover

            pass

        elif isinstance(key, binary_type):

            key = key.decode(_encoding)

        elif isinstance(key, float):

            key = _floatstr(key)

        elif key is True:

            key = 'true'

        elif key is False:

            key = 'false'

        elif key is None:

            key = 'null'

        elif isinstance(key, integer_types):

            key = str(key)

        elif _use_decimal and isinstance(key, Decimal):

            key = str(key)

        elif _skipkeys:

            key = None

        else:

            raise TypeError("key " + repr(key) + " is not a string")

        return key

    def _iterencode_dict(dct, _current_indent_level):

        if not dct:

            yield '{}'

            return

        if markers is not None:

            markerid = id(dct)

            if markerid in markers:

                raise ValueError("Circular reference detected")

            markers[markerid] = dct

        yield '{'

        if _indent is not None:

            _current_indent_level += 1

            newline_indent = '\n' + (_indent * _current_indent_level)

            item_separator = _item_separator + newline_indent

            yield newline_indent

        else:

            newline_indent = None

            item_separator = _item_separator

        first = True

        if _PY3:

            iteritems = dct.items()

        else:

            iteritems = dct.iteritems()

        if _item_sort_key:

            items = []

            for k, v in dct.items():

                if not isinstance(k, string_types):

                    k = _stringify_key(k)

                    if k is None:

                        continue

                items.append((k, v))

            items.sort(key=_item_sort_key)

        else:

            items = iteritems

        for key, value in items:

            if not (_item_sort_key or isinstance(key, string_types)):

                key = _stringify_key(key)

                if key is None:

                    # _skipkeys must be True

                    continue

            if first:

                first = False

            else:

                yield item_separator

            yield _encoder(key)

            yield _key_separator

            if (isinstance(value, string_types) or

                (_PY3 and isinstance(value, binary_type))):

                yield _encoder(value)

            elif value is None:

                yield 'null'

            elif value is True:

                yield 'true'

            elif value is False:

                yield 'false'

            elif isinstance(value, integer_types):

                yield _encode_int(value)

            elif isinstance(value, float):

                yield _floatstr(value)

            elif _use_decimal and isinstance(value, Decimal):

                yield str(value)

            else:

                for_json = _for_json and getattr(value, 'for_json', None)

                if for_json and callable(for_json):

                    chunks = _iterencode(for_json(), _current_indent_level)

                elif isinstance(value, list):

                    chunks = _iterencode_list(value, _current_indent_level)

                else:

                    _asdict = _namedtuple_as_object and getattr(value, '_asdict', None)

                    if _asdict and callable(_asdict):

                        chunks = _iterencode_dict(_asdict(),

                                                  _current_indent_level)

                    elif _tuple_as_array and isinstance(value, tuple):

                        chunks = _iterencode_list(value, _current_indent_level)

                    elif isinstance(value, dict):

                        chunks = _iterencode_dict(value, _current_indent_level)

                    else:

                        chunks = _iterencode(value, _current_indent_level)

                for chunk in chunks:

                    yield chunk

        if newline_indent is not None:

            _current_indent_level -= 1

            yield '\n' + (_indent * _current_indent_level)

        yield '}'

        if markers is not None:

            del markers[markerid]

    def _iterencode(o, _current_indent_level):

        if (isinstance(o, string_types) or

            (_PY3 and isinstance(o, binary_type))):

            yield _encoder(o)

        elif o is None:

            yield 'null'

        elif o is True:

            yield 'true'

        elif o is False:

            yield 'false'

        elif isinstance(o, integer_types):

            yield _encode_int(o)

        elif isinstance(o, float):

            yield _floatstr(o)

        else:

            for_json = _for_json and getattr(o, 'for_json', None)

            if for_json and callable(for_json):

                for chunk in _iterencode(for_json(), _current_indent_level):

                    yield chunk

            elif isinstance(o, list):

                for chunk in _iterencode_list(o, _current_indent_level):

                    yield chunk

            else:

                _asdict = _namedtuple_as_object and getattr(o, '_asdict', None)

                if _asdict and callable(_asdict):

                    for chunk in _iterencode_dict(_asdict(),

                            _current_indent_level):

                        yield chunk

                elif (_tuple_as_array and isinstance(o, tuple)):

                    for chunk in _iterencode_list(o, _current_indent_level):

                        yield chunk

                elif isinstance(o, dict):

                    for chunk in _iterencode_dict(o, _current_indent_level):

                        yield chunk

                elif _use_decimal and isinstance(o, Decimal):

                    yield str(o)

                else:

                    if markers is not None:

                        markerid = id(o)

                        if markerid in markers:

                            raise ValueError("Circular reference detected")

                        markers[markerid] = o

                    o = _default(o)

                    for chunk in _iterencode(o, _current_indent_level):

                        yield chunk

                    if markers is not None:

                        del markers[markerid]

    return _iterencode