[FIX] builtins removed from Python 3

* Reverse wrapper courtesy of @rco-odoo's original P3 branch
* thin compat module stripped down from werkzeug (to augment as needed)

issue 8530

11 files changed, 102 insertions, 28 deletions

diff --git a/odoo/tools/config.py b/odoo/tools/config.py
index c832c1980cd..4443bc7e6d7 100644
--- a/odoo/tools/config.py
+++ b/odoo/tools/config.py
@@ -549,7 +549,7 @@ class configmanager(object):
             if not rc_exists and not os.path.exists(os.path.dirname(self.rcfile)):
                 os.makedirs(os.path.dirname(self.rcfile))
             try:
-                p.write(file(self.rcfile, 'w'))
+                p.write(open(self.rcfile, 'w'))
                 if not rc_exists:
                     os.chmod(self.rcfile, 0o600)
             except IOError:
diff --git a/odoo/tools/convert.py b/odoo/tools/convert.py
index 3410b929bc6..3df1d20b50f 100644
--- a/odoo/tools/convert.py
+++ b/odoo/tools/convert.py
@@ -890,10 +890,10 @@ def convert_xml_import(cr, module, xmlfile, idref=None, mode='init', noupdate=Fa
 
     if idref is None:
         idref={}
-    if isinstance(xmlfile, file):
-        xml_filename = xmlfile.name
-    else:
+    if isinstance(xmlfile, basestring):
         xml_filename = xmlfile
+    else:
+        xml_filename = xmlfile.name
     obj = xml_import(cr, module, idref, mode, report=report, noupdate=noupdate, xml_filename=xml_filename)
     obj.parse(doc.getroot(), mode=mode)
     return True
diff --git a/odoo/tools/float_utils.py b/odoo/tools/float_utils.py
index 959299e2c97..8c71d7a29b2 100644
--- a/odoo/tools/float_utils.py
+++ b/odoo/tools/float_utils.py
@@ -4,6 +4,9 @@
 from __future__ import print_function
 import math
 
+from odoo.tools import pycompat
+
+
 def _float_check_precision(precision_digits=None, precision_rounding=None):
     assert (precision_digits is not None or precision_rounding is not None) and \
         not (precision_digits and precision_rounding),\
@@ -54,7 +57,7 @@ def float_round(value, precision_digits=None, precision_rounding=None, rounding_
     epsilon_magnitude = math.log(abs(normalized_value), 2)
     epsilon = 2**(epsilon_magnitude-53)
     if rounding_method == 'HALF-UP':
-        normalized_value += cmp(normalized_value,0) * epsilon
+        normalized_value += math.copysign(epsilon, normalized_value)
         rounded_value = round(normalized_value) # round to integer
 
     # TIE-BREAKING: UP (for ceiling operations)
@@ -66,7 +69,7 @@ def float_round(value, precision_digits=None, precision_rounding=None, rounding_
     # restored.
 
     elif rounding_method == 'UP':
-        sign = cmp(normalized_value, 0)
+        sign = math.copysign(1.0, normalized_value)
         normalized_value -= sign*epsilon
         rounded_value = math.ceil(abs(normalized_value))*sign # ceil to integer
 
@@ -214,14 +217,13 @@ if __name__ == "__main__":
     fractions = [.0, .015, .01499, .675, .67499, .4555, .4555, .45555]
     expecteds = ['.00', '.02', '.01', '.68', '.67', '.46', '.456', '.4556']
     precisions = [2, 2, 2, 2, 2, 2, 3, 4]
-    for magnitude in range(7):
-        for i in xrange(len(fractions)):
-            frac, exp, prec = fractions[i], expecteds[i], precisions[i]
+    for magnitude in pycompat.range(7):
+        for frac, exp, prec in zip(fractions, expecteds, precisions):
             for sign in [-1,1]:
-                for x in xrange(0,10000,97):
+                for x in pycompat.range(0, 10000, 97):
                     n = x * 10**magnitude
                     f = sign * (n + frac)
-                    f_exp = ('-' if f != 0 and sign == -1 else '') + str(n) + exp 
+                    f_exp = ('-' if f != 0 and sign == -1 else '') + str(n) + exp
                     try_round(f, f_exp, precision_digits=prec)
 
     stop = time.time()
diff --git a/odoo/tools/graph.py b/odoo/tools/graph.py
index 454a1dce98f..82fc0e0978a 100755
--- a/odoo/tools/graph.py
+++ b/odoo/tools/graph.py
@@ -634,7 +634,7 @@ class graph(object):
         self.init_order(self.start, self.result[self.start]['x'])
 
         for level in self.levels:
-            self.levels[level].sort(lambda x, y: cmp(self.result[x]['y'], self.result[y]['y']))
+            self.levels[level].sort(key=lambda x: self.result[x]['y'])
 
         self.order_heuristic()
         self.process_order()
diff --git a/odoo/tools/image.py b/odoo/tools/image.py
index 952d6b25c4c..481abd3da02 100644
--- a/odoo/tools/image.py
+++ b/odoo/tools/image.py
@@ -280,6 +280,6 @@ if __name__=="__main__":
 
     assert len(sys.argv)==3, 'Usage to Test: image.py SRC.png DEST.png'
 
-    img = file(sys.argv[1],'rb').read().encode('base64')
+    img = open(sys.argv[1],'rb').read().encode('base64')
     new = image_resize_image(img, (128,100))
-    file(sys.argv[2], 'wb').write(new.decode('base64'))
+    open(sys.argv[2], 'wb').write(new.decode('base64'))
diff --git a/odoo/tools/import_email.py b/odoo/tools/import_email.py
index 4178ca14a06..74029c693eb 100644
--- a/odoo/tools/import_email.py
+++ b/odoo/tools/import_email.py
@@ -125,7 +125,7 @@ class ReceiverEmail2Event(object):
                     os.mkdir(newdir)
 
                 counter += 1
-                fd = file(os.path.join(newdir, filename), 'w')
+                fd = open(os.path.join(newdir, filename), 'w')
                 fd.write(part.get_payload(decode=1))
                 fd.close()
         else:
diff --git a/odoo/tools/misc.py b/odoo/tools/misc.py
index f080d3067ca..d90031e43eb 100644
--- a/odoo/tools/misc.py
+++ b/odoo/tools/misc.py
@@ -27,6 +27,7 @@ from cStringIO import StringIO
 from collections import defaultdict, Iterable, Mapping, MutableSet, OrderedDict
 from itertools import islice, izip, groupby, repeat
 from lxml import etree
+
 from which import which
 from threading import local
 import traceback
@@ -41,6 +42,7 @@ except ImportError:
 from config import config
 from cache import *
 from .parse_version import parse_version 
+from . import pycompat
 
 import odoo
 # get_encodings, ustr and exception_to_unicode were originally from tools.misc.
@@ -279,7 +281,7 @@ def flatten(list):
     return r
 
 def reverse_enumerate(l):
-    """Like enumerate but in the other sens
+    """Like enumerate but in the other direction
     
     Usage::
     >>> a = ['a', 'b', 'c']
@@ -295,7 +297,7 @@ def reverse_enumerate(l):
       File "<stdin>", line 1, in <module>
     StopIteration
     """
-    return izip(xrange(len(l)-1, -1, -1), reversed(l))
+    return izip(pycompat.range(len(l)-1, -1, -1), reversed(l))
 
 def partition(pred, elems):
     """ Return a pair equivalent to:
@@ -654,8 +656,11 @@ def posix_to_ldml(fmt, locale):
 def split_every(n, iterable, piece_maker=tuple):
     """Splits an iterable into length-n pieces. The last piece will be shorter
        if ``n`` does not evenly divide the iterable length.
-       @param ``piece_maker``: function to build the pieces
-       from the slices (tuple,list,...)
+       
+       :param int n: maximum size of each generated chunk
+       :param Iterable iterable: iterable to chunk into pieces
+       :param piece_maker: callable taking an iterable and collecting each 
+                           chunk from its slice, *must consume the entire slice*.
     """
     iterator = iter(iterable)
     piece = piece_maker(islice(iterator, n))
@@ -990,6 +995,39 @@ class LastOrderedSet(OrderedSet):
         OrderedSet.discard(self, elem)
         OrderedSet.add(self, elem)
 
+def unique(it):
+    """ "Uniquifier" for the provided iterable: will output each element of
+    the iterable once.
+
+    The iterable's elements must be hashahble.
+
+    :param Iterable it:
+    :rtype: Iterator
+    """
+    seen = set()
+    for e in it:
+        if e not in seen:
+            seen.add(e)
+            yield e
+
+class Reverse(object):
+    """ Wraps a value and reverses its ordering, useful in key functions when
+    mixing ascending and descending sort on non-numeric data as the
+    ``reverse`` parameter can not do piecemeal reordering.
+    """
+    __slots__ = ['val']
+
+    def __init__(self, val):
+        self.val = val
+
+    def __eq__(self, other): return self.val == other.val
+    def __ne__(self, other): return self.val != other.val
+
+    def __ge__(self, other): return self.val <= other.val
+    def __gt__(self, other): return self.val < other.val
+    def __le__(self, other): return self.val >= other.val
+    def __lt__(self, other): return self.val > other.val
+
 @contextmanager
 def ignore(*exc):
     try:
diff --git a/odoo/tools/pycompat.py b/odoo/tools/pycompat.py
new file mode 100644
index 00000000000..114f7f2bd87
--- /dev/null
+++ b/odoo/tools/pycompat.py
@@ -0,0 +1,31 @@
+# -*- coding: utf-8 -*-
+# to remove if we decide to add a dependency on six or future
+# very strongly inspired by https://github.com/pallets/werkzeug/blob/master/werkzeug/_compat.py
+import sys
+
+PY2 = sys.version_info[0]
+
+if PY2:
+    # pylint: disable=long-builtin,xrange-builtin
+    integer_types = (int, long)
+
+    range = xrange
+
+    # noinspection PyUnresolvedReferences
+    from itertools import imap, izip, ifilter
+
+    def implements_iterator(cls):
+        cls.next = cls.__next__
+        del cls.__next__
+        return cls
+else:
+    integer_types = (int,)
+
+    range = range
+
+    imap = map
+    izip = zip
+    ifilter = filter
+
+    def implements_iterator(cls):
+        return cls
diff --git a/odoo/tools/safe_eval.py b/odoo/tools/safe_eval.py
index 14020378c21..ebe97619e35 100644
--- a/odoo/tools/safe_eval.py
+++ b/odoo/tools/safe_eval.py
@@ -16,11 +16,14 @@ condition/math builtins.
 #  - safe_eval in tryton http://hg.tryton.org/hgwebdir.cgi/trytond/rev/bbb5f73319ad
 
 from opcode import HAVE_ARGUMENT, opmap
+
+import functools
 from psycopg2 import OperationalError
 from types import CodeType
 import logging
 import werkzeug
 
+from odoo.tools import pycompat
 from .misc import ustr
 
 import odoo
@@ -226,7 +229,6 @@ _BUILTINS = {
     'bool': bool,
     'int': int,
     'float': float,
-    'long': long,
     'enumerate': enumerate,
     'dict': dict,
     'list': list,
@@ -236,7 +238,7 @@ _BUILTINS = {
     'min': min,
     'max': max,
     'sum': sum,
-    'reduce': reduce,
+    'reduce': functools.reduce,
     'filter': filter,
     'round': round,
     'len': len,
@@ -246,11 +248,10 @@ _BUILTINS = {
     'any': any,
     'ord': ord,
     'chr': chr,
-    'cmp': cmp,
     'divmod': divmod,
     'isinstance': isinstance,
     'range': range,
-    'xrange': xrange,
+    'xrange': pycompat.range,
     'zip': zip,
     'Exception': Exception,
 }
diff --git a/odoo/tools/test_reports.py b/odoo/tools/test_reports.py
index ef09862bc01..c1f9af8bb55 100644
--- a/odoo/tools/test_reports.py
+++ b/odoo/tools/test_reports.py
@@ -11,6 +11,8 @@ import odoo
 import odoo.report
 import odoo.tools as tools
 import logging
+
+from odoo.tools import pycompat
 from odoo.tools.safe_eval import safe_eval
 from subprocess import Popen, PIPE
 import os
@@ -45,7 +47,7 @@ def try_report(cr, uid, rname, ids, data=None, context=None, our_module=None, re
         raise ValueError("Report %s produced an empty result!" % rname)
 
     if tools.config['test_report_directory']:
-        file(os.path.join(tools.config['test_report_directory'], rname+ '.'+res_format), 'wb+').write(res_data)
+        open(os.path.join(tools.config['test_report_directory'], rname+ '.'+res_format), 'wb+').write(res_data)
 
     _logger.debug("Have a %s report for %s, will examine it", res_format, rname)
     if res_format == 'pdf':
@@ -128,7 +130,7 @@ def try_report_action(cr, uid, action_id, active_model=None, active_ids=None,
         action = env.ref(action_id)
         act_model, act_id = action._name, action.id
     else:
-        assert isinstance(action_id, (long, int))
+        assert isinstance(action_id, pycompat.integer_types)
         act_model = 'ir.action.act_window'     # assume that
         act_id = action_id
         act_xmlid = '<%s>' % act_id
diff --git a/odoo/tools/translate.py b/odoo/tools/translate.py
index 16a7bd9015e..75495b4bbae 100644
--- a/odoo/tools/translate.py
+++ b/odoo/tools/translate.py
@@ -20,7 +20,7 @@ from babel.messages import extract
 from lxml import etree
 
 import odoo
-from odoo.tools import config
+from odoo.tools import config, pycompat
 from odoo.tools.misc import file_open, get_iso_codes, SKIPPED_ELEMENT_TYPES
 from odoo.tools.osutil import walksymlinks
 from odoo import sql_db, SUPERUSER_ID
@@ -679,7 +679,7 @@ def trans_export(lang, modules, buffer, format, cr):
                 tmpmoddir = join(tmpdir, mod, 'i18n')
                 os.makedirs(tmpmoddir)
                 pofilename = (lang if lang else mod) + ".po" + ('t' if not lang else '')
-                buf = file(join(tmpmoddir, pofilename), 'w')
+                buf = open(join(tmpmoddir, pofilename), 'w')
                 _process('po', [mod], modrows, buf, lang)
                 buf.close()
 
@@ -1106,7 +1106,7 @@ def trans_load_data(cr, fileobj, fileformat, lang, lang_name=None, verbose=True,
             if not res_id:
                 return
 
-            if isinstance(res_id, (int, long)) or \
+            if isinstance(res_id, pycompat.integer_types) or \
                     (isinstance(res_id, basestring) and res_id.isdigit()):
                 dic['res_id'] = int(res_id)
                 if module_name: