Changeset 391 for python/trunk/Lib/json/decoder.py

Timestamp:

Mar 19, 2014, 11:31:01 PM (11 years ago)

Author:

dmik

Message:

python: Merge vendor 2.7.6 to trunk.

Location:

python/trunk

Files:

• . (modified) (1 prop)
• Lib/json/decoder.py (modified) (13 diffs)

python/trunk/Lib/json/decoder.py

@@ -1 +1 @@
 """Implementation of JSONDecoder
 """
-
 import re
 import sys
-
-from json.scanner import Scanner, pattern
+import struct
+
+from json import scanner
 try:
     from _json import scanstring as c_scanstring
@@ -15 +15 @@
 FLAGS = re.VERBOSE | re.MULTILINE | re.DOTALL
 
-NaN, PosInf, NegInf = float('nan'), float('inf'), float('-inf')
+def _floatconstants():
+    _BYTES = '7FF80000000000007FF0000000000000'.decode('hex')
+    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()
 
 
@@ -21 +28 @@
     lineno = doc.count('\n', 0, pos) + 1
     if lineno == 1:
-        colno = pos
+        colno = pos + 1
     else:
         colno = pos - doc.rindex('\n', 0, pos)
@@ -28 +35 @@
 
 def errmsg(msg, doc, pos, end=None):
+    # Note that this function is called from _json
     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)
 
 
@@ -41 +53 @@
     '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)
@@ -79 +63 @@
 DEFAULT_ENCODING = "utf-8"
 
-
-def py_scanstring(s, end, encoding=None, strict=True, _b=BACKSLASH, _m=STRINGCHUNK.match):
+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
@@ -93 +85 @@
         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 ValueError(errmsg(msg, s, end))
@@ -111 +107 @@
             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:
-                msg = "Invalid \\escape: {0!r}".format(esc)
+                msg = "Invalid \\escape: " + repr(esc)
                 raise ValueError(errmsg(msg, 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
-if c_scanstring is not None:
-    scanstring = c_scanstring
-else:
-    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)
-
-
-WHITESPACE = re.compile(r'\s*', FLAGS)
-
-
-def JSONObject(match, context, _w=WHITESPACE.match):
-    pairs = {}
-    s = match.string
-    end = _w(s, match.end()).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_and_end, encoding, strict, scan_once, object_hook,
+               object_pairs_hook, _w=WHITESPACE.match, _ws=WHITESPACE_STR):
+    s, end = s_and_end
+    pairs = []
+    pairs_append = pairs.append
+    # 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 == '}':
+            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 ValueError(errmsg(
+                "Expecting property name enclosed in double quotes", 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()
-        try:
-            value, end = iterscan(s, idx=end, context=context).next()
+            end = _w(s, end).end()
+            if s[end:end + 1] != ':':
+                raise ValueError(errmsg("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 ValueError(errmsg("Expecting object", s, end))
-        pairs[key] = value
-        end = _w(s, end).end()
-        nextchar = s[end:end + 1]
+        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
-        if nextchar != ',':
-            raise ValueError(errmsg("Expecting , delimiter", s, end - 1))
-        end = _w(s, end).end()
-        nextchar = s[end:end + 1]
+        elif nextchar != ',':
+            raise ValueError(errmsg("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 ValueError(errmsg("Expecting property name", s, end - 1))
-    object_hook = getattr(context, 'object_hook', None)
+            raise ValueError(errmsg(
+                "Expecting property name enclosed in double quotes", 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
-pattern(r'{')(JSONObject)
-
-
-def JSONArray(match, context, _w=WHITESPACE.match):
+
+def JSONArray(s_and_end, scan_once, _w=WHITESPACE.match, _ws=WHITESPACE_STR):
+    s, end = s_and_end
     values = []
-    s = match.string
-    end = _w(s, match.end()).end()
+    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
-    nextchar = s[end:end + 1]
     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 != ',':
-            raise ValueError(errmsg("Expecting , delimiter", s, end))
-        end = _w(s, end).end()
+        elif nextchar != ',':
+            raise ValueError(errmsg("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
-pattern(r'\[')(JSONArray)
-
-
-ANYTHING = [
-    JSONObject,
-    JSONArray,
-    JSONString,
-    JSONConstant,
-    JSONNumber,
-]
-
-JSONScanner = Scanner(ANYTHING)
-
 
 class JSONDecoder(object):
@@ -269 +298 @@
     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):
+            parse_int=None, parse_constant=None, strict=True,
+            object_pairs_hook=None):
         """``encoding`` determines the encoding used to interpret any ``str``
         objects decoded by this instance (utf-8 by default).  It has no
@@ -283 +311 @@
         strings of other encodings should be passed in as ``unicode``.
 
-        ``object_hook``, if specified, will be called with the result of
-        every JSON object decoded and its return value will be used in
+        ``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 ``dict``.  This can be used to provide custom
         deserializations (e.g. to support JSON-RPC class hinting).
+
+        ``object_pairs_hook``, if specified will be called with the result of
+        every JSON object decoded with an ordered list of pairs.  The return
+        value of ``object_pairs_hook`` will be used instead of the ``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,
+        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
@@ -299 +336 @@
 
         ``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.
+
+        If ``strict`` is false (true is the default), then control
+        characters will be allowed inside strings.  Control characters in
+        this context are those with character codes in the 0-31 range,
+        including ``'\\t'`` (tab), ``'\\n'``, ``'\\r'`` and ``'\\0'``.
 
         """
         self.encoding = encoding
         self.object_hook = object_hook
-        self.parse_float = parse_float
-        self.parse_int = parse_int
-        self.parse_constant = parse_constant
+        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.scan_once = scanner.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)
 
@@ -323 +369 @@
         return obj
 
-    def raw_decode(self, s, **kw):
-        """Decode a JSON document from ``s`` (a ``str`` or ``unicode`` beginning
-        with a JSON document) and return a 2-tuple of the Python
+    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.
 
@@ -332 +378 @@
 
         """
-        kw.setdefault('context', self)
-        try:
-            obj, end = self._scanner.iterscan(s, **kw).next()
+        try:
+            obj, end = self.scan_once(s, idx)
         except StopIteration:
             raise ValueError("No JSON object could be decoded")