Forward port r70471: Add object_pairs_hook. Issue 5381.

Lib/json/__init__.py

@@ -237,11 +237,12 @@ def dumps(obj, skipkeys=False, ensure_ascii=True, check_circular=True,
         **kw).encode(obj)
 
 
-_default_decoder = JSONDecoder(encoding=None, object_hook=None)
+_default_decoder = JSONDecoder(encoding=None, object_hook=None,
+                               object_pairs_hook=None)
 
 
 def load(fp, encoding=None, cls=None, object_hook=None, parse_float=None,
-        parse_int=None, parse_constant=None, **kw):
+        parse_int=None, parse_constant=None, object_pairs_hook=None, **kw):
     """Deserialize ``fp`` (a ``.read()``-supporting file-like object
     containing a JSON document) to a Python object.
 
@@ -264,11 +265,11 @@ def load(fp, encoding=None, cls=None, object_hook=None, parse_float=None,
     return loads(fp.read(),
         encoding=encoding, cls=cls, object_hook=object_hook,
         parse_float=parse_float, parse_int=parse_int,
-        parse_constant=parse_constant, **kw)
+        parse_constant=parse_constant, object_pairs_hook=object_pairs_hook, **kw)
 
 
 def loads(s, encoding=None, cls=None, object_hook=None, parse_float=None,
-        parse_int=None, parse_constant=None, **kw):
+        parse_int=None, parse_constant=None, object_pairs_hook=None, **kw):
     """Deserialize ``s`` (a ``str`` or ``unicode`` instance containing a JSON
     document) to a Python object.
 
@@ -303,12 +304,14 @@ def loads(s, encoding=None, cls=None, object_hook=None, parse_float=None,
     """
     if (cls is None and encoding is None and object_hook is None and
             parse_int is None and parse_float is None and
-            parse_constant is None and not kw):
+            parse_constant is None and object_pairs_hook is None and not kw):
         return _default_decoder.decode(s)
     if cls is None:
         cls = JSONDecoder
     if object_hook is not None:
         kw['object_hook'] = object_hook
+    if object_pairs_hook is not None:
+        kw['object_pairs_hook'] = object_pairs_hook
     if parse_float is not None:
         kw['parse_float'] = parse_float
     if parse_int is not None:

Lib/json/decoder.py

@@ -164,7 +164,8 @@ WHITESPACE = re.compile(r'\s*', FLAGS)
 
 
 def JSONObject(match, context, _w=WHITESPACE.match):
-    pairs = {}
+    pairs = []
+    pairs_append = pairs.append
     s = match.string
     end = _w(s, match.end()).end()
     nextchar = s[end:end + 1]
@@ -187,7 +188,7 @@ def JSONObject(match, context, _w=WHITESPACE.match):
             value, end = next(iterscan(s, idx=end, context=context))
         except StopIteration:
             raise ValueError(errmsg("Expecting object", s, end))
-        pairs[key] = value
+        pairs_append((key, value))
         end = _w(s, end).end()
         nextchar = s[end:end + 1]
         end += 1
@@ -200,6 +201,11 @@ def JSONObject(match, context, _w=WHITESPACE.match):
         end += 1
         if nextchar != '"':
             raise ValueError(errmsg("Expecting property name", s, end - 1))
+    object_pairs_hook = getattr(context, 'object_pairs_hook', None)
+    if object_pairs_hook is not None:
+        result = object_pairs_hook(pairs)
+        return result, end
+    pairs = dict(pairs)
     object_hook = getattr(context, 'object_hook', None)
     if object_hook is not None:
         pairs = object_hook(pairs)
@@ -278,7 +284,8 @@ class JSONDecoder(object):
     __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
         effect when decoding ``unicode`` objects.
@@ -309,6 +316,7 @@ class JSONDecoder(object):
         """
         self.encoding = encoding
         self.object_hook = object_hook
+        self.object_pairs_hook = object_pairs_hook
         self.parse_float = parse_float
         self.parse_int = parse_int
         self.parse_constant = parse_constant

Lib/json/tests/test_decode.py

 import decimal
 from unittest import TestCase
+from io import StringIO
 
 import json
+from collections import OrderedDict
 
 class TestDecode(TestCase):
     def test_decimal(self):
@@ -13,3 +15,20 @@ class TestDecode(TestCase):
         rval = json.loads('1', parse_int=float)
         self.assert_(isinstance(rval, float))
         self.assertEquals(rval, 1.0)
+
+    def test_object_pairs_hook(self):
+        s = '{"xkd":1, "kcw":2, "art":3, "hxm":4, "qrt":5, "pad":6, "hoy":7}'
+        p = [("xkd", 1), ("kcw", 2), ("art", 3), ("hxm", 4),
+             ("qrt", 5), ("pad", 6), ("hoy", 7)]
+        self.assertEqual(json.loads(s), eval(s))
+        self.assertEqual(json.loads(s, object_pairs_hook = lambda x: x), p)
+        self.assertEqual(json.load(StringIO(s),
+                                   object_pairs_hook=lambda x: x), p)
+        od = json.loads(s, object_pairs_hook = OrderedDict)
+        self.assertEqual(od, OrderedDict(p))
+        self.assertEqual(type(od), OrderedDict)
+        # the object_pairs_hook takes priority over the object_hook
+        self.assertEqual(json.loads(s,
+                                    object_pairs_hook = OrderedDict,
+                                    object_hook = lambda x: None),
+                         OrderedDict(p))

Lib/json/tests/test_unicode.py

 from unittest import TestCase
 
 import json
+from collections import OrderedDict
 
 class TestUnicode(TestCase):
     def test_encoding1(self):
@@ -53,3 +54,18 @@ class TestUnicode(TestCase):
             u = chr(i)
             js = '"\\u{0:04x}"'.format(i)
             self.assertEquals(json.loads(js), u)
+
+    def test_object_pairs_hook_with_unicode(self):
+        s = '{"xkd":1, "kcw":2, "art":3, "hxm":4, "qrt":5, "pad":6, "hoy":7}'
+        p = [("xkd", 1), ("kcw", 2), ("art", 3), ("hxm", 4),
+             ("qrt", 5), ("pad", 6), ("hoy", 7)]
+        self.assertEqual(json.loads(s), eval(s))
+        self.assertEqual(json.loads(s, object_pairs_hook = lambda x: x), p)
+        od = json.loads(s, object_pairs_hook = OrderedDict)
+        self.assertEqual(od, OrderedDict(p))
+        self.assertEqual(type(od), OrderedDict)
+        # the object_pairs_hook takes priority over the object_hook
+        self.assertEqual(json.loads(s,
+                                    object_pairs_hook = OrderedDict,
+                                    object_hook = lambda x: None),
+                         OrderedDict(p))