debug_info_test: replace whitelist with allowlist

This CL tweaks language to better reflect the intent that's meant to be
conveyed, per go/chromium-project-code-inclusion .

This change is meant to trivially be a local, functional nop; renaming
extensions will be a later CL.

BUG=chromium:1099035
TEST=CQ+1

Change-Id: Iaee8b96c54660b4ebb4363a230e768c3da3f885a
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/toolchain-utils/+/2265049
Reviewed-by: Manoj Gupta <manojgupta@chromium.org>
Tested-by: George Burgess <gbiv@chromium.org>
Commit-Queue: George Burgess <gbiv@chromium.org>

1 files changed, 69 insertions, 0 deletions

diff --git a/debug_info_test/allowlist.py b/debug_info_test/allowlist.py
new file mode 100644
index 00000000..978b2370
--- /dev/null
+++ b/debug_info_test/allowlist.py
@@ -0,0 +1,69 @@
+# -*- coding: utf-8 -*-
+# Copyright 2018 The Chromium OS Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Allowlist functions."""
+
+from __future__ import print_function
+
+import glob
+import os
+import re
+
+
+# Matching a string of length m in an NFA of size n is O(mn^2), but the
+# performance also depends largely on the implementation. It appears to be fast
+# enough according to the tests.
+#
+# The performance bottleneck of this script is readelf. Unless this becomes
+# slower than readelf, don't waste time here.
+def is_allowlisted(list_name, pattern):
+  """Check whether the given pattern is specified in the allowlist.
+
+  Args:
+    list_name: name of the allowlist.
+    pattern: the target string.
+
+  Returns:
+    True if matched otherwise False.
+  """
+  return pattern and allowlists[list_name].match(pattern)
+
+
+def prepare_allowlist(patterns):
+  """Join and compile the re patterns.
+
+  Args:
+    patterns: regex patterns.
+
+  Returns:
+    A compiled re object.
+  """
+  return re.compile('|'.join(patterns))
+
+
+# FIXME: s/whitelist/allowlist/ in the file extension.
+def load_allowlists(dirname):
+  """Load allowlists under dirname.
+
+  An allowlist ends with .whitelist.
+
+  Args:
+    dirname: path to the dir.
+
+  Returns:
+    A dictionary of 'filename' -> allowlist matcher.
+  """
+  wlist = {}
+  for fn in glob.glob(os.path.join(dirname, '*.whitelist')):
+    key = os.path.splitext(os.path.basename(fn))[0]
+    with open(fn, 'r', encoding='utf-8') as f:
+      patterns = f.read().splitlines()
+      patterns = [l for l in patterns if l != '']
+      patterns = [l for l in patterns if l[0] != '#']
+    wlist[key] = prepare_allowlist(patterns)
+  return wlist
+
+
+allowlists = load_allowlists(os.path.dirname(__file__))