[SuperSize] Modernize syntax for int divisions and exception variable assignments.

To aid in porting SuperSize to Python 3, this CL does the following:
* Sort out int vs. float divisions.
  * Add "'from __future__ import division" to each python file
    (except mock files for testing).
  * For int division: Use "//" (was "/")
  * For float division: Ensure this can be inferred, by using
    float(), or float constants (e.g., 1024.0).
* Change "except" variable assignment style.
  * Use "except Exception as e" (was "except Exception, e").

Bug: 1054018
Change-Id: I25925196fe33fc7f4ca28f126f180eb4060fa2b2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2094544
Commit-Queue: Samuel Huang <huangs@chromium.org>
Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Cr-Commit-Position: refs/heads/master@{#748375}

tools/binary_size/libsupersize/apkanalyzer.py

@@ -7,6 +7,8 @@
 Assumes that apk_path.mapping and apk_path.jar.info is available.
 """
 
+from __future__ import division
+
 import logging
 import os
 import subprocess

tools/binary_size/libsupersize/apkanalyzer_test.py

@@ -3,6 +3,8 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+from __future__ import division
+
 import unittest
 
 import apkanalyzer

tools/binary_size/libsupersize/ar.py

@@ -5,6 +5,7 @@
 
 """Logic for reading .a files."""
 
+from __future__ import division
 from __future__ import print_function
 
 import argparse

tools/binary_size/libsupersize/archive.py

@@ -4,6 +4,8 @@
 
 """Main Python API for analyzing binary size."""
 
+from __future__ import division
+
 import argparse
 import bisect
 import calendar

tools/binary_size/libsupersize/bcanalyzer.py

@@ -20,6 +20,7 @@ This file can also be run stand-alone in order to test out the logic on smaller
 sample sizes.
 """
 
+from __future__ import division
 from __future__ import print_function
 
 import argparse
@@ -225,7 +226,8 @@ class _BcTypeInfo:
       [size, item_type_id] = list(_ParseOpItems(line, attrib_pos))  # op0, op1.
       bits = self.int_types.get(item_type_id)
       if bits is not None:  # |bits| can be None for non-int arrays.
-        self.int_array_types[self.cur_type_id] = _BcIntArrayType(size, bits / 8)
+        self.int_array_types[self.cur_type_id] = _BcIntArrayType(
+            size, bits // 8)
     self.cur_type_id += 1
 
   def GetArrayType(self, idx):

tools/binary_size/libsupersize/bcanalyzer_test.py

@@ -3,6 +3,8 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+from __future__ import division
+
 import ast
 import os
 import unittest
@@ -31,7 +33,7 @@ def _MakeString(bits, toks):
     the result of concatanating tokens.
   """
   s = ''.join(tok if isinstance(tok, basestring) else chr(tok) for tok in toks)
-  padding = '\x00' * ((bits - 8) / 8)
+  padding = '\x00' * ((bits - 8) // 8)
   return ''.join(ch + padding for ch in s)
 
 

tools/binary_size/libsupersize/canned_queries.py

@@ -4,6 +4,8 @@
 
 """Contains a set of Chrome-specific size queries."""
 
+from __future__ import division
+
 import logging
 
 import models

tools/binary_size/libsupersize/concurrent.py

@@ -4,6 +4,8 @@
 
 """Helpers related to multiprocessing."""
 
+from __future__ import division
+
 import __builtin__  # __builtins__ does not have exception types.
 import atexit
 import itertools
@@ -68,7 +70,7 @@ class _FuncWrapper(object):
   def __call__(self, index, _=None):
     try:
       return self._func(*_fork_params[index], **_fork_kwargs)
-    except Exception, e:
+    except Exception as e:
       # Only keep the exception type for builtin exception types or else risk
       # further marshalling exceptions.
       exception_type = None

tools/binary_size/libsupersize/concurrent_test.py

@@ -3,6 +3,8 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+from __future__ import division
+
 import os
 import threading
 import unittest

tools/binary_size/libsupersize/console.py

@@ -4,6 +4,7 @@
 
 """An interactive console for looking analyzing .size files."""
 
+from __future__ import division
 from __future__ import print_function
 
 import argparse

tools/binary_size/libsupersize/demangle.py

@@ -4,6 +4,8 @@
 
 """Utilities for demangling C++ symbols."""
 
+from __future__ import division
+
 import collections
 import itertools
 import logging

tools/binary_size/libsupersize/describe.py

@@ -3,6 +3,8 @@
 # found in the LICENSE file.
 """Methods for converting model objects to human-readable formats."""
 
+from __future__ import division
+
 import abc
 import cStringIO
 import collections
@@ -109,7 +111,7 @@ class Histogram(object):
     bucket_values = [str(self.data[k]) for k in keys]
     num_items = len(keys)
     num_cols = 6
-    num_rows = (num_items + num_cols - 1) / num_cols  # Divide and round up.
+    num_rows = (num_items + num_cols - 1) // num_cols  # Divide and round up.
     # Needed for xrange to not throw due to step by 0.
     if num_rows == 0:
       return
@@ -287,7 +289,7 @@ class DescriberText(Describer):
       #   * Accounts for < .5% of PSS
       #   * Symbols are smaller than 1.0 byte (by PSS)
       #   * Always show at least 50 symbols.
-      min_remaining_pss_to_show = max(1024, total / 1000 * 5)
+      min_remaining_pss_to_show = max(1024.0, total / 1000.0 * 5)
       min_symbol_pss_to_show = 1.0
       min_symbols_to_show = 50
 

tools/binary_size/libsupersize/diff.py

@@ -3,6 +3,8 @@
 # found in the LICENSE file.
 """Logic for diffing two SizeInfo objects."""
 
+from __future__ import division
+
 import collections
 import logging
 import re

tools/binary_size/libsupersize/diff_test.py

@@ -3,6 +3,8 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+from __future__ import division
+
 import unittest
 
 import diff

tools/binary_size/libsupersize/file_format.py

@@ -101,6 +101,8 @@ All remaining bytes are a valid gzipped sparse .size file containing the
 "after" snapshot.
 """
 
+from __future__ import division
+
 import cStringIO
 import contextlib
 import gzip

tools/binary_size/libsupersize/function_signature.py

@@ -7,6 +7,8 @@
 Much of this logic is duplicated at
 tools/binary_size/libsupersize/caspian/function_signature.cc."""
 
+from __future__ import division
+
 
 def _FindParameterListParen(name):
   """Finds index of the "(" that denotes the start of a parameter list."""

tools/binary_size/libsupersize/function_signature_test.py

@@ -3,6 +3,8 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+from __future__ import division
+
 import logging
 import re
 import unittest

tools/binary_size/libsupersize/html_report.py

@@ -4,6 +4,7 @@
 
 """Creates an html report that allows you to view binary size by component."""
 
+from __future__ import division
 from __future__ import print_function
 
 import codecs

tools/binary_size/libsupersize/integration_test.py

@@ -3,6 +3,8 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+from __future__ import division
+
 import cStringIO
 import contextlib
 import copy

tools/binary_size/libsupersize/linker_map_parser.py

@@ -18,6 +18,7 @@ The |linker_name| parameter in various functions must take one of the above
 coded linker name values.
 """
 
+from __future__ import division
 from __future__ import print_function
 
 import argparse

tools/binary_size/libsupersize/linker_map_parser_test.py

@@ -3,6 +3,8 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+from __future__ import division
+
 import glob
 import os
 import sys

tools/binary_size/libsupersize/main.py

@@ -5,6 +5,8 @@
 
 """Collect, archive, and analyze Chrome's binary size."""
 
+from __future__ import division
+
 import argparse
 import atexit
 import collections
@@ -26,7 +28,7 @@ import start_server
 def _LogPeakRamUsage():
   peak_ram_usage = resource.getrusage(resource.RUSAGE_SELF).ru_maxrss
   peak_ram_usage += resource.getrusage(resource.RUSAGE_CHILDREN).ru_maxrss
-  logging.info('Peak RAM usage was %d MB.', peak_ram_usage / 1024)
+  logging.info('Peak RAM usage was %d MB.', peak_ram_usage // 1024)
 
 
 def _AddCommonArguments(parser):

tools/binary_size/libsupersize/match_util.py

@@ -4,6 +4,8 @@
 
 """Regular expression helpers."""
 
+from __future__ import division
+
 import re
 
 

tools/binary_size/libsupersize/match_util_test.py

@@ -3,6 +3,8 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+from __future__ import division
+
 import re
 import unittest
 

tools/binary_size/libsupersize/models.py

@@ -28,6 +28,8 @@ Description of common properties:
         Never None, but will be '' when no component exists.
 """
 
+from __future__ import division
+
 import collections
 import logging
 import os

tools/binary_size/libsupersize/ninja_parser.py

@@ -4,6 +4,7 @@
 # found in the LICENSE file.
 """Extract source file information from .ninja files."""
 
+from __future__ import division
 from __future__ import print_function
 
 import argparse

tools/binary_size/libsupersize/ninja_parser_test.py

@@ -3,6 +3,8 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+from __future__ import division
+
 import unittest
 
 import ninja_parser

tools/binary_size/libsupersize/nm.py

@@ -17,6 +17,8 @@ RunNmOnIntermediates():
   offset information.
 """
 
+from __future__ import division
+
 import collections
 import subprocess
 

tools/binary_size/libsupersize/obj_analyzer.py

@@ -35,6 +35,7 @@ This file can also be run stand-alone in order to test out the logic on smaller
 sample sizes.
 """
 
+from __future__ import division
 from __future__ import print_function
 
 import argparse
@@ -389,7 +390,7 @@ class _BulkObjectFileAnalyzerSlave(object):
         self._HandleMessage(self._pipe.recv())
     except EOFError:
       pass
-    except EnvironmentError, e:
+    except EnvironmentError as e:
       # Parent process exited so don't log.
       if e.errno in (errno.EPIPE, errno.ECONNRESET):
         sys.exit(1)

tools/binary_size/libsupersize/path_util.py

@@ -4,6 +4,8 @@
 
 """Functions for dealing with determining --tool-prefix."""
 
+from __future__ import division
+
 import abc
 import distutils.spawn
 import logging

tools/binary_size/libsupersize/run_tests.py

@@ -3,6 +3,8 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+from __future__ import division
+
 import logging
 import os
 import sys

tools/binary_size/libsupersize/start_server.py

@@ -4,6 +4,8 @@
 
 """Runs a server to let the user interact with supersize using a web UI."""
 
+from __future__ import division
+
 import BaseHTTPServer
 import logging
 import os

tools/binary_size/libsupersize/string_extract.py

@@ -31,6 +31,8 @@ ResolveStringPieces():
   - Returns [{path: [string_ranges]} for each string_section].
 """
 
+from __future__ import division
+
 import ast
 import collections
 import itertools

tools/binary_size/libsupersize/test_util.py

@@ -2,6 +2,8 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+from __future__ import division
+
 import difflib
 import logging
 

tools/binary_size/libsupersize/upload_html_viewer.py

@@ -5,6 +5,8 @@
 
 """Update the Google Cloud Storage bucket hosting the Super Size UI."""
 
+from __future__ import division
+
 import argparse
 import os
 import subprocess