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python: Serial JSON via Python's json lib.

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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.

Signed-off-by: Terry Wilson <twilson@redhat.com>
Signed-off-by: Ben Pfaff <blp@ovn.org>
This commit is contained in:
Terry Wilson
2016-07-25 19:17:11 -05:00
committed by Ben Pfaff
parent 9364ae6548
commit 622749d8a3
2 changed files with 30 additions and 102 deletions
Download Patch File Download Diff File Expand all files Collapse all files

106
python/ovs/json.py
View File

@@ -12,11 +12,13 @@
# See the License for the specific language governing permissions and # See the License for the specific language governing permissions and
# limitations under the License. # limitations under the License.
from __future__ import absolute_import
import functools
import json
import re import re
import sys import sys
import six import six
from six.moves import range
try: try:
import ovs._json import ovs._json
@@ -25,112 +27,24 @@ except ImportError:
__pychecker__ = 'no-stringiter' __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 SPACES_PER_LEVEL = 2
dumper = functools.partial(json.dumps, separators=(",", ":"),
ensure_ascii=False)
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)
def to_stream(obj, stream, pretty=False, sort_keys=True): 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): def to_file(obj, name, pretty=False, sort_keys=True):
stream = open(name, "w") with open(name, "w") as stream:
try:
to_stream(obj, stream, pretty, sort_keys) to_stream(obj, stream, pretty, sort_keys)
finally:
stream.close()
def to_string(obj, pretty=False, sort_keys=True): def to_string(obj, pretty=False, sort_keys=True):
output = six.StringIO() return dumper(obj, indent=SPACES_PER_LEVEL if pretty else None,
to_stream(obj, output, pretty, sort_keys) sort_keys=sort_keys)
s = output.getvalue()
output.close()
return s
def from_stream(stream): def from_stream(stream):

26
tests/json.at
View File

@@ -1,4 +1,4 @@
m4_define([JSON_CHECK_POSITIVE_C], m4_define([JSON_CHECK_POSITIVE_C],
[AT_SETUP([$1]) [AT_SETUP([$1])
AT_KEYWORDS([json positive]) AT_KEYWORDS([json positive])
AT_CHECK([printf %s "AS_ESCAPE([$2])" > input]) AT_CHECK([printf %s "AS_ESCAPE([$2])" > input])
@@ -11,7 +11,7 @@ m4_define([JSON_CHECK_POSITIVE_C],
# JSON_CHECK_POSITIVE_PY(TITLE, INPUT, OUTPUT, TEST-JSON-ARGS, # JSON_CHECK_POSITIVE_PY(TITLE, INPUT, OUTPUT, TEST-JSON-ARGS,
# PYTHON-CHCEK, PYTHON-BIN) # PYTHON-CHCEK, PYTHON-BIN)
# #
m4_define([JSON_CHECK_POSITIVE_PY], m4_define([JSON_CHECK_POSITIVE_PY],
[AT_SETUP([$1]) [AT_SETUP([$1])
AT_KEYWORDS([json positive Python]) AT_KEYWORDS([json positive Python])
AT_SKIP_IF([test $5 = no]) AT_SKIP_IF([test $5 = no])
@@ -41,6 +41,12 @@ m4_define([JSON_CHECK_POSITIVE],
JSON_CHECK_POSITIVE_PY([$1 - Python3], [$2], [$3], [$4], JSON_CHECK_POSITIVE_PY([$1 - Python3], [$2], [$3], [$4],
[$HAVE_PYTHON3], [$PYTHON3])]) [$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], m4_define([JSON_CHECK_NEGATIVE_C],
[AT_SETUP([$1]) [AT_SETUP([$1])
AT_KEYWORDS([json negative]) AT_KEYWORDS([json negative])
@@ -216,10 +222,14 @@ JSON_CHECK_POSITIVE(
# It seems likely that the following test will fail on some system that # 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 # rounds slightly differently in arithmetic or in printf, but I'd like
# to keep it this way until we run into such a system. # to keep it this way until we run into such a system.
JSON_CHECK_POSITIVE( JSON_CHECK_POSITIVE_C(
[large integers that overflow to reals], [C - large integers that overflow to reals],
[[[9223372036854775807000, -92233720368547758080000]]], [[[9223372036854775807000, -92233720368547758080000]]],
[[[9.22337203685478e+21,-9.22337203685478e+22]]]) [[[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( JSON_CHECK_POSITIVE(
[negative zero], [negative zero],
@@ -237,10 +247,14 @@ JSON_CHECK_POSITIVE(
# It seems likely that the following test will fail on some system that # 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 # rounds slightly differently in arithmetic or in printf, but I'd like
# to keep it this way until we run into such a system. # to keep it this way until we run into such a system.
JSON_CHECK_POSITIVE( JSON_CHECK_POSITIVE_C(
[+/- DBL_MAX], [C - +/- DBL_MAX],
[[[1.7976931348623157e+308, -1.7976931348623157e+308]]], [[[1.7976931348623157e+308, -1.7976931348623157e+308]]],
[[[1.79769313486232e+308,-1.79769313486232e+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( JSON_CHECK_POSITIVE(
[negative reals], [negative reals],