diff options
Diffstat (limited to 'django/utils/simplejson/decoder.py')
| -rw-r--r-- | django/utils/simplejson/decoder.py | 272 |
1 files changed, 137 insertions, 135 deletions
diff --git a/django/utils/simplejson/decoder.py b/django/utils/simplejson/decoder.py index cef9fc002b..5a845ccfdc 100644 --- a/django/utils/simplejson/decoder.py +++ b/django/utils/simplejson/decoder.py @@ -1,20 +1,17 @@ -""" -Implementation of JSONDecoder +"""Implementation of JSONDecoder """ import re import sys +import struct + +from django.utils.simplejson.scanner import make_scanner +c_scanstring = None -from django.utils.simplejson.scanner import Scanner, pattern -try: - from django.utils.simplejson._speedups import scanstring as c_scanstring -except ImportError: - pass +__all__ = ['JSONDecoder'] FLAGS = re.VERBOSE | re.MULTILINE | re.DOTALL def _floatconstants(): - import struct - import sys _BYTES = '7FF80000000000007FF0000000000000'.decode('hex') if sys.byteorder != 'big': _BYTES = _BYTES[:8][::-1] + _BYTES[8:][::-1] @@ -34,6 +31,7 @@ def linecol(doc, pos): def errmsg(msg, doc, pos, end=None): + # Note that this function is called from _speedups lineno, colno = linecol(doc, pos) if end is None: return '%s: line %d column %d (char %d)' % (msg, lineno, colno, pos) @@ -46,35 +44,8 @@ _CONSTANTS = { '-Infinity': NegInf, 'Infinity': PosInf, 'NaN': NaN, - 'true': True, - 'false': False, - 'null': None, } -def JSONConstant(match, context, c=_CONSTANTS): - s = match.group(0) - fn = getattr(context, 'parse_constant', None) - if fn is None: - rval = c[s] - else: - rval = fn(s) - return rval, None -pattern('(-?Infinity|NaN|true|false|null)')(JSONConstant) - - -def JSONNumber(match, context): - match = JSONNumber.regex.match(match.string, *match.span()) - integer, frac, exp = match.groups() - if frac or exp: - fn = getattr(context, 'parse_float', None) or float - res = fn(integer + (frac or '') + (exp or '')) - else: - fn = getattr(context, 'parse_int', None) or int - res = fn(integer) - return res, None -pattern(r'(-?(?:0|[1-9]\d*))(\.\d+)?([eE][-+]?\d+)?')(JSONNumber) - - STRINGCHUNK = re.compile(r'(.*?)(["\\\x00-\x1f])', FLAGS) BACKSLASH = { '"': u'"', '\\': u'\\', '/': u'/', @@ -84,6 +55,14 @@ BACKSLASH = { 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 = [] @@ -96,15 +75,19 @@ def py_scanstring(s, end, encoding=None, strict=True, _b=BACKSLASH, _m=STRINGCHU errmsg("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: - raise ValueError(errmsg("Invalid control character %r at", s, end)) + msg = "Invalid control character %r at" % (terminator,) + raise ValueError(msg, s, end) else: _append(terminator) continue @@ -113,142 +96,162 @@ def py_scanstring(s, end, encoding=None, strict=True, _b=BACKSLASH, _m=STRINGCHU except IndexError: raise ValueError( errmsg("Unterminated string starting at", s, begin)) + # If not a unicode escape sequence, must be in the lookup table if esc != 'u': try: - m = _b[esc] + char = _b[esc] except KeyError: raise ValueError( errmsg("Invalid \\escape: %r" % (esc,), s, end)) end += 1 else: + # Unicode escape sequence esc = s[end + 1:end + 5] next_end = end + 5 - msg = "Invalid \\uXXXX escape" - try: - if len(esc) != 4: - raise ValueError - uni = int(esc, 16) - if 0xd800 <= uni <= 0xdbff and sys.maxunicode > 65535: - msg = "Invalid \\uXXXX\\uXXXX surrogate pair" - if not s[end + 5:end + 7] == '\\u': - raise ValueError - esc2 = s[end + 7:end + 11] - if len(esc2) != 4: - raise ValueError - uni2 = int(esc2, 16) - uni = 0x10000 + (((uni - 0xd800) << 10) | (uni2 - 0xdc00)) - next_end += 6 - m = unichr(uni) - except ValueError: + if len(esc) != 4: + msg = "Invalid \\uXXXX escape" raise ValueError(errmsg(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 ValueError(errmsg(msg, s, end)) + esc2 = s[end + 7:end + 11] + if len(esc2) != 4: + raise ValueError(errmsg(msg, s, end)) + uni2 = int(esc2, 16) + uni = 0x10000 + (((uni - 0xd800) << 10) | (uni2 - 0xdc00)) + next_end += 6 + char = unichr(uni) end = next_end - _append(m) + # Append the unescaped character + _append(char) return u''.join(chunks), end -# Use speedup -try: - scanstring = c_scanstring -except NameError: - scanstring = py_scanstring - -def JSONString(match, context): - encoding = getattr(context, 'encoding', None) - strict = getattr(context, 'strict', True) - return scanstring(match.string, match.end(), encoding, strict) -pattern(r'"')(JSONString) +# Use speedup if available +scanstring = c_scanstring or py_scanstring +WHITESPACE = re.compile(r'[ \t\n\r]*', FLAGS) +WHITESPACE_STR = ' \t\n\r' -WHITESPACE = re.compile(r'\s*', FLAGS) - -def JSONObject(match, context, _w=WHITESPACE.match): +def JSONObject((s, end), encoding, strict, scan_once, object_hook, _w=WHITESPACE.match, _ws=WHITESPACE_STR): pairs = {} - s = match.string - end = _w(s, match.end()).end() + # 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] - # Trivial empty object - if nextchar == '}': - return pairs, end + 1 + # Normally we expect nextchar == '"' if nextchar != '"': - raise ValueError(errmsg("Expecting property name", s, end)) + if nextchar in _ws: + end = _w(s, end).end() + nextchar = s[end:end + 1] + # Trivial empty object + if nextchar == '}': + return pairs, end + 1 + elif nextchar != '"': + raise ValueError(errmsg("Expecting property name", s, end)) end += 1 - encoding = getattr(context, 'encoding', None) - strict = getattr(context, 'strict', True) - iterscan = JSONScanner.iterscan while True: key, end = scanstring(s, end, encoding, strict) - end = _w(s, end).end() + + # To skip some function call overhead we optimize the fast paths where + # the JSON key separator is ": " or just ":". if s[end:end + 1] != ':': - raise ValueError(errmsg("Expecting : delimiter", s, end)) - end = _w(s, end + 1).end() + end = _w(s, end).end() + if s[end:end + 1] != ':': + raise ValueError(errmsg("Expecting : delimiter", s, end)) + + end += 1 + try: - value, end = iterscan(s, idx=end, context=context).next() + 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 ValueError(errmsg("Expecting object", s, end)) pairs[key] = value - end = _w(s, end).end() - nextchar = s[end:end + 1] + + 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 - if nextchar != ',': + elif nextchar != ',': raise ValueError(errmsg("Expecting , delimiter", s, end - 1)) - end = _w(s, end).end() - nextchar = s[end: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 ValueError(errmsg("Expecting property name", s, end - 1)) - object_hook = getattr(context, 'object_hook', None) + if object_hook is not None: pairs = object_hook(pairs) return pairs, end -pattern(r'{')(JSONObject) - -def JSONArray(match, context, _w=WHITESPACE.match): +def JSONArray((s, end), scan_once, _w=WHITESPACE.match, _ws=WHITESPACE_STR): values = [] - s = match.string - end = _w(s, match.end()).end() - # Look-ahead for trivial empty array 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 - iterscan = JSONScanner.iterscan + _append = values.append while True: try: - value, end = iterscan(s, idx=end, context=context).next() + value, end = scan_once(s, end) except StopIteration: raise ValueError(errmsg("Expecting object", s, end)) - values.append(value) - end = _w(s, end).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 - if nextchar != ',': + elif nextchar != ',': raise ValueError(errmsg("Expecting , delimiter", s, end)) - end = _w(s, end).end() - return values, end -pattern(r'\[')(JSONArray) + try: + if s[end] in _ws: + end += 1 + if s[end] in _ws: + end = _w(s, end + 1).end() + except IndexError: + pass -ANYTHING = [ - JSONObject, - JSONArray, - JSONString, - JSONConstant, - JSONNumber, -] - -JSONScanner = Scanner(ANYTHING) - + return values, end class JSONDecoder(object): - """ - Simple JSON <http://json.org> decoder + """Simple JSON <http://json.org> decoder Performs the following translations in decoding by default: - + +---------------+-------------------+ | JSON | Python | +===============+===================+ @@ -271,18 +274,15 @@ class JSONDecoder(object): It also understands ``NaN``, ``Infinity``, and ``-Infinity`` as their corresponding ``float`` values, which is outside the JSON spec. - """ - _scanner = Scanner(ANYTHING) - __all__ = ['__init__', 'decode', 'raw_decode'] + """ def __init__(self, encoding=None, object_hook=None, parse_float=None, parse_int=None, parse_constant=None, strict=True): - """ - ``encoding`` determines the encoding used to interpret any ``str`` + """``encoding`` determines the encoding used to interpret any ``str`` objects decoded by this instance (utf-8 by default). It has no effect when decoding ``unicode`` objects. - + Note that currently only encodings that are a superset of ASCII work, strings of other encodings should be passed in as ``unicode``. @@ -302,21 +302,26 @@ class JSONDecoder(object): for JSON integers (e.g. float). ``parse_constant``, if specified, will be called with one of the - following strings: -Infinity, Infinity, NaN, null, true, false. + following strings: -Infinity, Infinity, NaN. This can be used to raise an exception if invalid JSON numbers are encountered. + """ self.encoding = encoding self.object_hook = object_hook - self.parse_float = parse_float - self.parse_int = parse_int - self.parse_constant = parse_constant + 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.scan_once = make_scanner(self) def decode(self, s, _w=WHITESPACE.match): - """ - Return the Python representation of ``s`` (a ``str`` or ``unicode`` + """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() @@ -324,20 +329,17 @@ class JSONDecoder(object): raise ValueError(errmsg("Extra data", s, end, len(s))) return obj - def raw_decode(self, s, **kw): - """ - Decode a JSON document from ``s`` (a ``str`` or ``unicode`` beginning + 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. + """ - kw.setdefault('context', self) try: - obj, end = self._scanner.iterscan(s, **kw).next() + obj, end = self.scan_once(s, idx) except StopIteration: raise ValueError("No JSON object could be decoded") return obj, end - -__all__ = ['JSONDecoder'] |
