Prepare for python3 compatibility [1]

Summary:
This is a first step towards python3 compatibility. Specifically, it
tackles:

 - `cPickle`: uses six.moves
 - `Queue`: uses six.moves
 - `urllib2`: uses six.moves and changes `urllib2.urlopen` to `urllib.request.urlopen`

Also, fundamentally it changes the types of all config "byte" types to
"string" types. Those configurations aren't un-encoded byte streams but very
specifically ascii (or unicode encoded) strings which are specified and
consumed by human eyes.

Reviewed By: rbgirshick

Differential Revision: D9662024

fbshipit-source-id: b8372f685b57ec4260ae881a2f8bb7967f337b10

detectron/datasets/json_dataset.py

@@ -26,11 +26,11 @@ from __future__ import print_function
 from __future__ import unicode_literals
 
 import copy
-import cPickle as pickle
 import logging
 import numpy as np
 import os
 import scipy.sparse
+from six.moves import cPickle as pickle
 
 # Must happen before importing COCO API (which imports matplotlib)
 import detectron.utils.env as envu

detectron/datasets/voc_eval.py

@@ -22,11 +22,11 @@
 
 """Python implementation of the PASCAL VOC devkit's AP evaluation code."""
 
-import cPickle
 import logging
 import numpy as np
 import os
 import xml.etree.ElementTree as ET
+from six.moves import cPickle
 
 logger = logging.getLogger(__name__)
 

detectron/roi_data/loader.py

@@ -44,11 +44,11 @@ from collections import deque
 from collections import OrderedDict
 import logging
 import numpy as np
-import Queue
 import signal
 import threading
 import time
 import uuid
+from six.moves import queue as Queue
 
 from caffe2.python import core, workspace
 

detectron/utils/blob.py

@@ -28,9 +28,9 @@ from __future__ import division
 from __future__ import print_function
 from __future__ import unicode_literals
 
-import cPickle as pickle
 import cv2
 import numpy as np
+from six.moves import cPickle as pickle
 
 from caffe2.proto import caffe2_pb2
 

detectron/utils/coordinator.py

@@ -22,9 +22,9 @@ from __future__ import unicode_literals
 
 import contextlib
 import logging
-import Queue
 import threading
 import traceback
+from six.moves import queue as Queue
 
 log = logging.getLogger(__name__)
 

detectron/utils/io.py

@@ -20,13 +20,13 @@ from __future__ import division
 from __future__ import print_function
 from __future__ import unicode_literals
 
-import cPickle as pickle
 import hashlib
 import logging
 import os
 import re
 import sys
-import urllib2
+from six.moves import cPickle as pickle
+from six.moves import urllib
 
 logger = logging.getLogger(__name__)
 
@@ -45,7 +45,9 @@ def cache_url(url_or_file, cache_dir):
     path to the cached file. If the argument is not a URL, simply return it as
     is.
     """
-    is_url = re.match(r'^(?:http)s?://', url_or_file, re.IGNORECASE) is not None
+    is_url = re.match(
+        r'^(?:http)s?://', url_or_file, re.IGNORECASE
+    ) is not None
 
     if not is_url:
         return url_or_file
@@ -111,7 +113,7 @@ def download_url(
     Credit:
     https://stackoverflow.com/questions/2028517/python-urllib2-progress-hook
     """
-    response = urllib2.urlopen(url)
+    response = urllib.request.urlopen(url)
     total_size = response.info().getheader('Content-Length').strip()
     total_size = int(total_size)
     bytes_so_far = 0
@@ -140,5 +142,5 @@ def _get_file_md5sum(file_name):
 def _get_reference_md5sum(url):
     """By convention the md5 hash for url is stored in url + '.md5sum'."""
     url_md5sum = url + '.md5sum'
-    md5sum = urllib2.urlopen(url_md5sum).read().strip()
+    md5sum = urllib.request.urlopen(url_md5sum).read().strip()
     return md5sum

detectron/utils/net.py

@@ -21,12 +21,12 @@ from __future__ import print_function
 from __future__ import unicode_literals
 
 from collections import OrderedDict
-import cPickle as pickle
 import logging
 import numpy as np
 import os
 import pprint
 import yaml
+from six.moves import cPickle as pickle
 
 from caffe2.python import core
 from caffe2.python import workspace

detectron/utils/subprocess.py

@@ -27,7 +27,7 @@ import os
 import yaml
 import numpy as np
 import subprocess
-import cPickle as pickle
+from six.moves import cPickle as pickle
 from six.moves import shlex_quote
 
 from detectron.core.config import cfg

requirements.txt

@@ -6,3 +6,4 @@ setuptools
 Cython
 mock
 scipy
+six

tools/convert_coco_model_to_cityscapes.py

@@ -9,10 +9,10 @@ from __future__ import print_function
 from __future__ import unicode_literals
 
 import argparse
-import cPickle as pickle
 import numpy as np
 import os
 import sys
+from six.moves import cPickle as pickle
 
 import detectron.datasets.coco_to_cityscapes_id as cs
 

tools/convert_selective_search.py

@@ -24,10 +24,10 @@ from __future__ import division
 from __future__ import print_function
 from __future__ import unicode_literals
 
-import cPickle as pickle
 import numpy as np
 import scipy.io as sio
 import sys
+from six.moves import cPickle as pickle
 
 from detectron.datasets.json_dataset import JsonDataset
 

tools/pickle_caffe_blobs.py

@@ -26,10 +26,10 @@ from __future__ import print_function
 from __future__ import unicode_literals
 
 import argparse
-import cPickle as pickle
 import numpy as np
 import os
 import sys
+from six.moves import cPickle as pickle
 
 from caffe.proto import caffe_pb2
 from caffe2.proto import caffe2_pb2

tools/reval.py

@@ -31,10 +31,10 @@ from __future__ import print_function
 from __future__ import unicode_literals
 
 import argparse
-import cPickle as pickle
 import os
 import sys
 import yaml
+from six.moves import cPickle as pickle
 
 from detectron.core.config import cfg
 from detectron.datasets import task_evaluation

tools/visualize_results.py

@@ -23,10 +23,10 @@ from __future__ import print_function
 from __future__ import unicode_literals
 
 import argparse
-import cPickle as pickle
 import cv2
 import os
 import sys
+from six.moves import cPickle as pickle
 
 from detectron.datasets.json_dataset import JsonDataset
 import detectron.utils.vis as vis_utils