| Index: pylib/simplejson/decoder.py
|
| ===================================================================
|
| --- pylib/simplejson/decoder.py (revision 0)
|
| +++ pylib/simplejson/decoder.py (revision 0)
|
| @@ -0,0 +1,421 @@
|
| +"""Implementation of JSONDecoder
|
| +"""
|
| +import re
|
| +import sys
|
| +import struct
|
| +
|
| +from simplejson.scanner import make_scanner
|
| +def _import_c_scanstring():
|
| + try:
|
| + from simplejson._speedups import scanstring
|
| + return scanstring
|
| + except ImportError:
|
| + return None
|
| +c_scanstring = _import_c_scanstring()
|
| +
|
| +__all__ = ['JSONDecoder']
|
| +
|
| +FLAGS = re.VERBOSE | re.MULTILINE | re.DOTALL
|
| +
|
| +def _floatconstants():
|
| + _BYTES = '7FF80000000000007FF0000000000000'.decode('hex')
|
| + # The struct module in Python 2.4 would get frexp() out of range here
|
| + # when an endian is specified in the format string. Fixed in Python 2.5+
|
| + if sys.byteorder != 'big':
|
| + _BYTES = _BYTES[:8][::-1] + _BYTES[8:][::-1]
|
| + nan, inf = struct.unpack('dd', _BYTES)
|
| + return nan, inf, -inf
|
| +
|
| +NaN, PosInf, NegInf = _floatconstants()
|
| +
|
| +
|
| +class JSONDecodeError(ValueError):
|
| + """Subclass of ValueError with the following additional properties:
|
| +
|
| + msg: The unformatted error message
|
| + doc: The JSON document being parsed
|
| + pos: The start index of doc where parsing failed
|
| + end: The end index of doc where parsing failed (may be None)
|
| + lineno: The line corresponding to pos
|
| + colno: The column corresponding to pos
|
| + endlineno: The line corresponding to end (may be None)
|
| + endcolno: The column corresponding to end (may be None)
|
| +
|
| + """
|
| + def __init__(self, msg, doc, pos, end=None):
|
| + ValueError.__init__(self, errmsg(msg, doc, pos, end=end))
|
| + self.msg = msg
|
| + self.doc = doc
|
| + self.pos = pos
|
| + self.end = end
|
| + self.lineno, self.colno = linecol(doc, pos)
|
| + if end is not None:
|
| + self.endlineno, self.endcolno = linecol(doc, end)
|
| + else:
|
| + self.endlineno, self.endcolno = None, None
|
| +
|
| +
|
| +def linecol(doc, pos):
|
| + lineno = doc.count('\n', 0, pos) + 1
|
| + if lineno == 1:
|
| + colno = pos
|
| + else:
|
| + colno = pos - doc.rindex('\n', 0, pos)
|
| + return lineno, colno
|
| +
|
| +
|
| +def errmsg(msg, doc, pos, end=None):
|
| + # Note that this function is called from _speedups
|
| + lineno, colno = linecol(doc, pos)
|
| + if end is None:
|
| + #fmt = '{0}: line {1} column {2} (char {3})'
|
| + #return fmt.format(msg, lineno, colno, pos)
|
| + fmt = '%s: line %d column %d (char %d)'
|
| + return fmt % (msg, lineno, colno, pos)
|
| + endlineno, endcolno = linecol(doc, end)
|
| + #fmt = '{0}: line {1} column {2} - line {3} column {4} (char {5} - {6})'
|
| + #return fmt.format(msg, lineno, colno, endlineno, endcolno, pos, end)
|
| + fmt = '%s: line %d column %d - line %d column %d (char %d - %d)'
|
| + return fmt % (msg, lineno, colno, endlineno, endcolno, pos, end)
|
| +
|
| +
|
| +_CONSTANTS = {
|
| + '-Infinity': NegInf,
|
| + 'Infinity': PosInf,
|
| + 'NaN': NaN,
|
| +}
|
| +
|
| +STRINGCHUNK = re.compile(r'(.*?)(["\\\x00-\x1f])', FLAGS)
|
| +BACKSLASH = {
|
| + '"': u'"', '\\': u'\\', '/': u'/',
|
| + 'b': u'\b', 'f': u'\f', 'n': u'\n', 'r': u'\r', 't': u'\t',
|
| +}
|
| +
|
| +DEFAULT_ENCODING = "utf-8"
|
| +
|
| +def py_scanstring(s, end, encoding=None, strict=True,
|
| + _b=BACKSLASH, _m=STRINGCHUNK.match):
|
| + """Scan the string s for a JSON string. End is the index of the
|
| + character in s after the quote that started the JSON string.
|
| + Unescapes all valid JSON string escape sequences and raises ValueError
|
| + on attempt to decode an invalid string. If strict is False then literal
|
| + control characters are allowed in the string.
|
| +
|
| + Returns a tuple of the decoded string and the index of the character in s
|
| + after the end quote."""
|
| + if encoding is None:
|
| + encoding = DEFAULT_ENCODING
|
| + chunks = []
|
| + _append = chunks.append
|
| + begin = end - 1
|
| + while 1:
|
| + chunk = _m(s, end)
|
| + if chunk is None:
|
| + raise JSONDecodeError(
|
| + "Unterminated string starting at", s, begin)
|
| + end = chunk.end()
|
| + content, terminator = chunk.groups()
|
| + # Content is contains zero or more unescaped string characters
|
| + if content:
|
| + if not isinstance(content, unicode):
|
| + content = unicode(content, encoding)
|
| + _append(content)
|
| + # Terminator is the end of string, a literal control character,
|
| + # or a backslash denoting that an escape sequence follows
|
| + if terminator == '"':
|
| + break
|
| + elif terminator != '\\':
|
| + if strict:
|
| + msg = "Invalid control character %r at" % (terminator,)
|
| + #msg = "Invalid control character {0!r} at".format(terminator)
|
| + raise JSONDecodeError(msg, s, end)
|
| + else:
|
| + _append(terminator)
|
| + continue
|
| + try:
|
| + esc = s[end]
|
| + except IndexError:
|
| + raise JSONDecodeError(
|
| + "Unterminated string starting at", s, begin)
|
| + # If not a unicode escape sequence, must be in the lookup table
|
| + if esc != 'u':
|
| + try:
|
| + char = _b[esc]
|
| + except KeyError:
|
| + msg = "Invalid \\escape: " + repr(esc)
|
| + raise JSONDecodeError(msg, s, end)
|
| + end += 1
|
| + else:
|
| + # Unicode escape sequence
|
| + esc = s[end + 1:end + 5]
|
| + next_end = end + 5
|
| + if len(esc) != 4:
|
| + msg = "Invalid \\uXXXX escape"
|
| + raise JSONDecodeError(msg, s, end)
|
| + uni = int(esc, 16)
|
| + # Check for surrogate pair on UCS-4 systems
|
| + if 0xd800 <= uni <= 0xdbff and sys.maxunicode > 65535:
|
| + msg = "Invalid \\uXXXX\\uXXXX surrogate pair"
|
| + if not s[end + 5:end + 7] == '\\u':
|
| + raise JSONDecodeError(msg, s, end)
|
| + esc2 = s[end + 7:end + 11]
|
| + if len(esc2) != 4:
|
| + raise JSONDecodeError(msg, s, end)
|
| + uni2 = int(esc2, 16)
|
| + uni = 0x10000 + (((uni - 0xd800) << 10) | (uni2 - 0xdc00))
|
| + next_end += 6
|
| + char = unichr(uni)
|
| + end = next_end
|
| + # Append the unescaped character
|
| + _append(char)
|
| + return u''.join(chunks), end
|
| +
|
| +
|
| +# Use speedup if available
|
| +scanstring = c_scanstring or py_scanstring
|
| +
|
| +WHITESPACE = re.compile(r'[ \t\n\r]*', FLAGS)
|
| +WHITESPACE_STR = ' \t\n\r'
|
| +
|
| +def JSONObject((s, end), encoding, strict, scan_once, object_hook,
|
| + object_pairs_hook, memo=None,
|
| + _w=WHITESPACE.match, _ws=WHITESPACE_STR):
|
| + # Backwards compatibility
|
| + if memo is None:
|
| + memo = {}
|
| + memo_get = memo.setdefault
|
| + pairs = []
|
| + # Use a slice to prevent IndexError from being raised, the following
|
| + # check will raise a more specific ValueError if the string is empty
|
| + nextchar = s[end:end + 1]
|
| + # Normally we expect nextchar == '"'
|
| + if nextchar != '"':
|
| + if nextchar in _ws:
|
| + end = _w(s, end).end()
|
| + nextchar = s[end:end + 1]
|
| + # Trivial empty object
|
| + if nextchar == '}':
|
| + if object_pairs_hook is not None:
|
| + result = object_pairs_hook(pairs)
|
| + return result, end + 1
|
| + pairs = {}
|
| + if object_hook is not None:
|
| + pairs = object_hook(pairs)
|
| + return pairs, end + 1
|
| + elif nextchar != '"':
|
| + raise JSONDecodeError("Expecting property name", s, end)
|
| + end += 1
|
| + while True:
|
| + key, end = scanstring(s, end, encoding, strict)
|
| + key = memo_get(key, key)
|
| +
|
| + # To skip some function call overhead we optimize the fast paths where
|
| + # the JSON key separator is ": " or just ":".
|
| + if s[end:end + 1] != ':':
|
| + end = _w(s, end).end()
|
| + if s[end:end + 1] != ':':
|
| + raise JSONDecodeError("Expecting : delimiter", s, end)
|
| +
|
| + end += 1
|
| +
|
| + try:
|
| + if s[end] in _ws:
|
| + end += 1
|
| + if s[end] in _ws:
|
| + end = _w(s, end + 1).end()
|
| + except IndexError:
|
| + pass
|
| +
|
| + try:
|
| + value, end = scan_once(s, end)
|
| + except StopIteration:
|
| + raise JSONDecodeError("Expecting object", s, end)
|
| + pairs.append((key, value))
|
| +
|
| + try:
|
| + nextchar = s[end]
|
| + if nextchar in _ws:
|
| + end = _w(s, end + 1).end()
|
| + nextchar = s[end]
|
| + except IndexError:
|
| + nextchar = ''
|
| + end += 1
|
| +
|
| + if nextchar == '}':
|
| + break
|
| + elif nextchar != ',':
|
| + raise JSONDecodeError("Expecting , delimiter", s, end - 1)
|
| +
|
| + try:
|
| + nextchar = s[end]
|
| + if nextchar in _ws:
|
| + end += 1
|
| + nextchar = s[end]
|
| + if nextchar in _ws:
|
| + end = _w(s, end + 1).end()
|
| + nextchar = s[end]
|
| + except IndexError:
|
| + nextchar = ''
|
| +
|
| + end += 1
|
| + if nextchar != '"':
|
| + raise JSONDecodeError("Expecting property name", s, end - 1)
|
| +
|
| + if object_pairs_hook is not None:
|
| + result = object_pairs_hook(pairs)
|
| + return result, end
|
| + pairs = dict(pairs)
|
| + if object_hook is not None:
|
| + pairs = object_hook(pairs)
|
| + return pairs, end
|
| +
|
| +def JSONArray((s, end), scan_once, _w=WHITESPACE.match, _ws=WHITESPACE_STR):
|
| + values = []
|
| + nextchar = s[end:end + 1]
|
| + if nextchar in _ws:
|
| + end = _w(s, end + 1).end()
|
| + nextchar = s[end:end + 1]
|
| + # Look-ahead for trivial empty array
|
| + if nextchar == ']':
|
| + return values, end + 1
|
| + _append = values.append
|
| + while True:
|
| + try:
|
| + value, end = scan_once(s, end)
|
| + except StopIteration:
|
| + raise JSONDecodeError("Expecting object", s, end)
|
| + _append(value)
|
| + nextchar = s[end:end + 1]
|
| + if nextchar in _ws:
|
| + end = _w(s, end + 1).end()
|
| + nextchar = s[end:end + 1]
|
| + end += 1
|
| + if nextchar == ']':
|
| + break
|
| + elif nextchar != ',':
|
| + raise JSONDecodeError("Expecting , delimiter", s, end)
|
| +
|
| + try:
|
| + if s[end] in _ws:
|
| + end += 1
|
| + if s[end] in _ws:
|
| + end = _w(s, end + 1).end()
|
| + except IndexError:
|
| + pass
|
| +
|
| + return values, end
|
| +
|
| +class JSONDecoder(object):
|
| + """Simple JSON <http://json.org> decoder
|
| +
|
| + Performs the following translations in decoding by default:
|
| +
|
| + +---------------+-------------------+
|
| + | JSON | Python |
|
| + +===============+===================+
|
| + | object | dict |
|
| + +---------------+-------------------+
|
| + | array | list |
|
| + +---------------+-------------------+
|
| + | string | unicode |
|
| + +---------------+-------------------+
|
| + | number (int) | int, long |
|
| + +---------------+-------------------+
|
| + | number (real) | float |
|
| + +---------------+-------------------+
|
| + | true | True |
|
| + +---------------+-------------------+
|
| + | false | False |
|
| + +---------------+-------------------+
|
| + | null | None |
|
| + +---------------+-------------------+
|
| +
|
| + It also understands ``NaN``, ``Infinity``, and ``-Infinity`` as
|
| + their corresponding ``float`` values, which is outside the JSON spec.
|
| +
|
| + """
|
| +
|
| + def __init__(self, encoding=None, object_hook=None, parse_float=None,
|
| + parse_int=None, parse_constant=None, strict=True,
|
| + object_pairs_hook=None):
|
| + """
|
| + *encoding* determines the encoding used to interpret any
|
| + :class:`str` objects decoded by this instance (``'utf-8'`` by
|
| + default). It has no effect when decoding :class:`unicode` objects.
|
| +
|
| + Note that currently only encodings that are a superset of ASCII work,
|
| + strings of other encodings should be passed in as :class:`unicode`.
|
| +
|
| + *object_hook*, if specified, will be called with the result of every
|
| + JSON object decoded and its return value will be used in place of the
|
| + given :class:`dict`. This can be used to provide custom
|
| + deserializations (e.g. to support JSON-RPC class hinting).
|
| +
|
| + *object_pairs_hook* is an optional function that will be called with
|
| + the result of any object literal decode with an ordered list of pairs.
|
| + The return value of *object_pairs_hook* will be used instead of the
|
| + :class:`dict`. This feature can be used to implement custom decoders
|
| + that rely on the order that the key and value pairs are decoded (for
|
| + example, :func:`collections.OrderedDict` will remember the order of
|
| + insertion). If *object_hook* is also defined, the *object_pairs_hook*
|
| + takes priority.
|
| +
|
| + *parse_float*, if specified, will be called with the string of every
|
| + JSON float to be decoded. By default, this is equivalent to
|
| + ``float(num_str)``. This can be used to use another datatype or parser
|
| + for JSON floats (e.g. :class:`decimal.Decimal`).
|
| +
|
| + *parse_int*, if specified, will be called with the string of every
|
| + JSON int to be decoded. By default, this is equivalent to
|
| + ``int(num_str)``. This can be used to use another datatype or parser
|
| + for JSON integers (e.g. :class:`float`).
|
| +
|
| + *parse_constant*, if specified, will be called with one of the
|
| + following strings: ``'-Infinity'``, ``'Infinity'``, ``'NaN'``. This
|
| + can be used to raise an exception if invalid JSON numbers are
|
| + encountered.
|
| +
|
| + *strict* controls the parser's behavior when it encounters an
|
| + invalid control character in a string. The default setting of
|
| + ``True`` means that unescaped control characters are parse errors, if
|
| + ``False`` then control characters will be allowed in strings.
|
| +
|
| + """
|
| + self.encoding = encoding
|
| + self.object_hook = object_hook
|
| + self.object_pairs_hook = object_pairs_hook
|
| + self.parse_float = parse_float or float
|
| + self.parse_int = parse_int or int
|
| + self.parse_constant = parse_constant or _CONSTANTS.__getitem__
|
| + self.strict = strict
|
| + self.parse_object = JSONObject
|
| + self.parse_array = JSONArray
|
| + self.parse_string = scanstring
|
| + self.memo = {}
|
| + self.scan_once = make_scanner(self)
|
| +
|
| + def decode(self, s, _w=WHITESPACE.match):
|
| + """Return the Python representation of ``s`` (a ``str`` or ``unicode``
|
| + instance containing a JSON document)
|
| +
|
| + """
|
| + obj, end = self.raw_decode(s, idx=_w(s, 0).end())
|
| + end = _w(s, end).end()
|
| + if end != len(s):
|
| + raise JSONDecodeError("Extra data", s, end, len(s))
|
| + return obj
|
| +
|
| + def raw_decode(self, s, idx=0):
|
| + """Decode a JSON document from ``s`` (a ``str`` or ``unicode``
|
| + beginning with a JSON document) and return a 2-tuple of the Python
|
| + representation and the index in ``s`` where the document ended.
|
| +
|
| + This can be used to decode a JSON document from a string that may
|
| + have extraneous data at the end.
|
| +
|
| + """
|
| + try:
|
| + obj, end = self.scan_once(s, idx)
|
| + except StopIteration:
|
| + raise JSONDecodeError("No JSON object could be decoded", s, idx)
|
| + return obj, end
|
|
|