V1 of //tools/binary_size rewrite

tools/binary_size/helpers.py

Index: tools/binary_size/helpers.py
diff --git a/tools/binary_size/helpers.py b/tools/binary_size/helpers.py
new file mode 100644
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+++ b/tools/binary_size/helpers.py
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+# Copyright 2017 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Utility methods."""
+
+import atexit
+import distutils.spawn
+import logging
+import os
+import platform
+import resource
+import sys
+
+
+SRC_ROOT = os.path.dirname(os.path.dirname(os.path.dirname(__file__)))
+
+
+def AddCommonOptionsAndParseArgs(parser):
+  parser.add_argument('--no-pypy', action='store_true',
+                      help='Do not automatically switch to pypy when available')
+  parser.add_argument('-v',
+                      '--verbose',
+                      default=0,
+                      action='count',
+                      help='Verbose level (multiple times for more)')
+
+  args = parser.parse_args()
+
+  logging.basicConfig(level=logging.WARNING - args.verbose * 10,
+                      format='%(levelname).1s %(relativeCreated)6d %(message)s')
+
+  if not args.no_pypy and platform.python_implementation() == 'CPython':
+    # Switch to pypy if it's available.
+    pypy_path = distutils.spawn.find_executable('pypy')
+    if pypy_path:
+      logging.debug('Switching to pypy.')
+      os.execv(pypy_path, [pypy_path] + sys.argv)
+    # NOTE! Running with python: 6s. Running with pypy: 3s
+    logging.warning('This script runs more than 2x faster if you install pypy.')
+
+  if logging.getLogger().isEnabledFor(logging.DEBUG):
+    atexit.register(_LogPeakRamUsage)
+  return args
+
+
+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)