[ovs-dev] [PATCH 2/2] JSON serialization via Python's json lib
Terry Wilson
twilson at redhat.com
Fri May 6 13:18:52 UTC 2016
There is no particularly good reason to use our own Python JSON
serialization implementation when serialization can be done faster
with Python's built-in JSON library.
A few tests were changed due to Python's default JSON library
returning slightly more precise floating point numbers and returning
'0.0' for 1e-9999 where the in-tree version returns '0'.
---
python/ovs/json.py | 106 +++++------------------------------------------------
tests/json.at | 38 +++++++++++++++----
2 files changed, 40 insertions(+), 104 deletions(-)
diff --git a/python/ovs/json.py b/python/ovs/json.py
index f1a6499..793ac17 100644
--- a/python/ovs/json.py
+++ b/python/ovs/json.py
@@ -12,11 +12,13 @@
# See the License for the specific language governing permissions and
# limitations under the License.
+from __future__ import absolute_import
+import functools
+import json
import re
import sys
import six
-from six.moves import range
try:
import ovs._json
@@ -25,112 +27,24 @@ except ImportError:
__pychecker__ = 'no-stringiter'
-escapes = {ord('"'): u"\\\"",
- ord("\\"): u"\\\\",
- ord("\b"): u"\\b",
- ord("\f"): u"\\f",
- ord("\n"): u"\\n",
- ord("\r"): u"\\r",
- ord("\t"): u"\\t"}
-for esc in range(32):
- if esc not in escapes:
- escapes[esc] = u"\\u%04x" % esc
-
SPACES_PER_LEVEL = 2
-
-
-class _Serializer(object):
- def __init__(self, stream, pretty, sort_keys):
- self.stream = stream
- self.pretty = pretty
- self.sort_keys = sort_keys
- self.depth = 0
-
- def __serialize_string(self, s):
- self.stream.write(u'"%s"' % ''.join(escapes.get(ord(c), c) for c in s))
-
- def __indent_line(self):
- if self.pretty:
- self.stream.write('\n')
- self.stream.write(' ' * (SPACES_PER_LEVEL * self.depth))
-
- def serialize(self, obj):
- if obj is None:
- self.stream.write(u"null")
- elif obj is False:
- self.stream.write(u"false")
- elif obj is True:
- self.stream.write(u"true")
- elif isinstance(obj, six.integer_types):
- self.stream.write(u"%d" % obj)
- elif isinstance(obj, float):
- self.stream.write("%.15g" % obj)
- elif isinstance(obj, six.text_type):
- # unicode() on Python 2, or str() in Python 3 (always unicode)
- self.__serialize_string(obj)
- elif isinstance(obj, str):
- # This is for Python 2, where this comes out to unicode(str()).
- # For Python 3, it's str(str()), but it's harmless.
- self.__serialize_string(six.text_type(obj))
- elif isinstance(obj, dict):
- self.stream.write(u"{")
-
- self.depth += 1
- self.__indent_line()
-
- if self.sort_keys:
- items = sorted(obj.items())
- else:
- items = six.iteritems(obj)
- for i, (key, value) in enumerate(items):
- if i > 0:
- self.stream.write(u",")
- self.__indent_line()
- self.__serialize_string(six.text_type(key))
- self.stream.write(u":")
- if self.pretty:
- self.stream.write(u' ')
- self.serialize(value)
-
- self.stream.write(u"}")
- self.depth -= 1
- elif isinstance(obj, (list, tuple)):
- self.stream.write(u"[")
- self.depth += 1
-
- if obj:
- self.__indent_line()
-
- for i, value in enumerate(obj):
- if i > 0:
- self.stream.write(u",")
- self.__indent_line()
- self.serialize(value)
-
- self.depth -= 1
- self.stream.write(u"]")
- else:
- raise Exception("can't serialize %s as JSON" % obj)
+dumper = functools.partial(json.dumps, separators=(",", ":"),
+ ensure_ascii=False)
def to_stream(obj, stream, pretty=False, sort_keys=True):
- _Serializer(stream, pretty, sort_keys).serialize(obj)
+ stream.write(dumper(obj, indent=SPACES_PER_LEVEL if pretty else None,
+ sort_keys=sort_keys))
def to_file(obj, name, pretty=False, sort_keys=True):
- stream = open(name, "w")
- try:
+ with open(name, "w") as stream:
to_stream(obj, stream, pretty, sort_keys)
- finally:
- stream.close()
def to_string(obj, pretty=False, sort_keys=True):
- output = six.StringIO()
- to_stream(obj, output, pretty, sort_keys)
- s = output.getvalue()
- output.close()
- return s
+ return dumper(obj, indent=SPACES_PER_LEVEL if pretty else None,
+ sort_keys=sort_keys)
def from_stream(stream):
diff --git a/tests/json.at b/tests/json.at
index 32d7fff..57a97b0 100644
--- a/tests/json.at
+++ b/tests/json.at
@@ -41,6 +41,12 @@ m4_define([JSON_CHECK_POSITIVE],
JSON_CHECK_POSITIVE_PY([$1 - Python3], [$2], [$3], [$4],
[$HAVE_PYTHON3], [$PYTHON3])])
+m4_define([JSON_CHECK_POSITIVE_PY23],
+ [JSON_CHECK_POSITIVE_PY([$1 - Python2], [$2], [$3], [$4],
+ [$HAVE_PYTHON], [$PYTHON])
+ JSON_CHECK_POSITIVE_PY([$1 - Python3], [$2], [$3], [$4],
+ [$HAVE_PYTHON3], [$PYTHON3])])
+
m4_define([JSON_CHECK_NEGATIVE_C],
[AT_SETUP([$1])
AT_KEYWORDS([json negative])
@@ -216,15 +222,23 @@ JSON_CHECK_POSITIVE(
# It seems likely that the following test will fail on some system that
# rounds slightly differently in arithmetic or in printf, but I'd like
# to keep it this way until we run into such a system.
-JSON_CHECK_POSITIVE(
- [large integers that overflow to reals],
+JSON_CHECK_POSITIVE_C(
+ [C - large integers that overflow to reals],
[[[9223372036854775807000, -92233720368547758080000]]],
[[[9.22337203685478e+21,-9.22337203685478e+22]]])
+JSON_CHECK_POSITIVE_PY23(
+ [large integers that overflow to reals],
+ [[[9223372036854775807000, -92233720368547758080000]]],
+ [[[9.223372036854776e+21,-9.223372036854776e+22]]])
-JSON_CHECK_POSITIVE(
- [negative zero],
+JSON_CHECK_POSITIVE_C(
+ [C - negative zero],
[[[-0, -0.0, 1e-9999, -1e-9999]]],
[[[0,0,0,0]]])
+JSON_CHECK_POSITIVE_PY23(
+ [negative zero],
+ [[[-0, -0.0, 1e-9999, -1e-9999]]],
+ [[[0,0,0.0,0.0]]])
JSON_CHECK_POSITIVE(
[reals],
@@ -237,10 +251,14 @@ JSON_CHECK_POSITIVE(
# It seems likely that the following test will fail on some system that
# rounds slightly differently in arithmetic or in printf, but I'd like
# to keep it this way until we run into such a system.
-JSON_CHECK_POSITIVE(
- [+/- DBL_MAX],
+JSON_CHECK_POSITIVE_C(
+ [C - +/- DBL_MAX],
[[[1.7976931348623157e+308, -1.7976931348623157e+308]]],
[[[1.79769313486232e+308,-1.79769313486232e+308]]])
+JSON_CHECK_POSITIVE_PY23(
+ [+/- DBL_MAX],
+ [[[1.7976931348623157e+308, -1.7976931348623157e+308]]],
+ [[[1.7976931348623157e+308,-1.7976931348623157e+308]]])
JSON_CHECK_POSITIVE(
[negative reals],
@@ -250,10 +268,14 @@ JSON_CHECK_POSITIVE(
[negative scientific notation],
[[[-1e3, -1E3, -2.5E2, -1e+3, -125e-3, -3.125e-2, -3125e-05, -1.525878906e-5]]],
[[[-1000,-1000,-250,-1000,-0.125,-0.03125,-0.03125,-1.525878906e-05]]])
-JSON_CHECK_POSITIVE(
- [1e-9999 underflows to 0],
+JSON_CHECK_POSITIVE_C(
+ [C - 1e-9999 underflows to 0],
[[[1e-9999]]],
[[[0]]])
+JSON_CHECK_POSITIVE_PY23(
+ [1e-9999 underflows to 0],
+ [[[1e-9999]]],
+ [[[0.0]]])
JSON_CHECK_NEGATIVE([a number by itself is not valid JSON], [1],
[error: syntax error at beginning of input])
JSON_CHECK_NEGATIVE(
--
1.8.3.1
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