Add logdog_helper script.

build/android/pylib/utils/decorators.py

+# Copyright 2017 The Chromium Authors. All rights reserved.

[jbudorick, 2017/02/03 01:35:42]

This should have tests.

+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import functools
+import logging
+
+
+def Memoize(f):
+  """Decorator to cache return values of function."""
+
+  memoize_dict = {}
+  @functools.wraps(f)
+  def wrapper(*args, **kwargs):
+    key = repr((args, kwargs))
+    if key not in memoize_dict:
+      try:
+        memoize_dict[key] = f(*args, **kwargs)
+      except Exception as e:  # pylint: disable=broad-except
+        memoize_dict[key] = e

[jbudorick, 2017/02/03 01:30:30]

This is... interesting. I'm not sure we want to do this.

[mikecase (-- gone --), 2017/02/03 18:28:39]

Changed to not cache Exceptions.

+        raise
+    return_value = memoize_dict[key]
+    if isinstance(return_value, Exception):
+      raise return_value
+    return return_value
+  return wrapper
+
+
+def NoRaiseException(default_return_value=None, exception_message=''):
+  """Returns decorator that catches and logs uncaught Exceptions.
+
+  Args:
+    default_return_value: Value to return in the case of uncaught Exception.
+    exception_message: Message for uncaught exceptions.
+  """
+  def decorator(f):
+    @functools.wraps(f)
+    def wrapper(*args, **kwargs):
+      try:
+        return f(*args, **kwargs)
+      except Exception:  # pylint: disable=broad-except
+        logging.exception(exception_message)
+        return default_return_value
+    return wrapper
+  return decorator