[Android WebView] Rewrite copyrights scanner in Python

android_webview/tools/copyright_scanner.py

Index: android_webview/tools/copyright_scanner.py
diff --git a/android_webview/tools/copyright_scanner.py b/android_webview/tools/copyright_scanner.py
new file mode 100644
index 0000000000000000000000000000000000000000..c68b7507794681304ad9fb72f9e8cca1b7095bfc
--- /dev/null
+++ b/android_webview/tools/copyright_scanner.py
@@ -0,0 +1,195 @@
+# Copyright 2014 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.
+
+"""Utilities for scanning source files to determine code authorship.
+"""
+
+import itertools
+import os
+import re
+
+
+def FindFiles(root_dir, start_paths_list, excluded_dirs_list):
+  """Similar to UNIX utility find(1), searches for files in the directories.
+  Automatically leaves out only source code files.
+  Args:
+    root_dir: The root directory, to which all other paths are relative.
+    start_paths_list: The list of paths to start search from. Each path can
+      be a file or a directory.
+    excluded_dirs_list: The list of directories to skip.
+  Returns:
+    The list of source code files found, relative to |root_dir|.
+  """
+  dirs_blacklist = ['/' + d + '/' for d in excluded_dirs_list]
+  def IsBlacklistedDir(d):
+    for item in dirs_blacklist:
+      if item in d:
+        return True
+    return False
+
+  files_whitelist_re = re.compile(
+    r'\.(asm|c(c|pp|xx)?|h(h|pp|xx)?|p(l|m)|xs|sh|php|py(|x)'
+    '|rb|idl|java|el|sc(i|e)|cs|pas|inc|js|pac|html|dtd|xsl|mod|mm?'
+    '|tex|mli?)$')
+  files = []
+
+  base_path_len = len(root_dir)
+  for path in start_paths_list:
+    full_path = os.path.join(root_dir, path)
+    if os.path.isfile(full_path):
+      if files_whitelist_re.search(path):
+        files.append(path)
+    else:
+      for dirpath, dirnames, filenames in os.walk(full_path):
+        # Remove excluded subdirs for faster scanning.
+        for item in dirnames[:]:
+          if IsBlacklistedDir(os.path.join(dirpath, item)[base_path_len + 1:]):
+            dirnames.remove(item)

[mkosiba (inactive), 2014/10/02 13:14:46]

the os.walk docs say:
so I guess you'll want to os.walk(full_path, topdown=True)

[mnaganov (inactive), 2014/10/02 13:51:30]

Yeah, but the same doc also lists the defaults for this function:

os.walk(top, topdown=True, onerror=None, followlinks=False)

+        for filename in filenames:
+          filepath = os.path.join(dirpath, filename)[base_path_len + 1:]
+          if files_whitelist_re.search(filepath) and \
+              not IsBlacklistedDir(filepath):
+            files.append(filepath)
+  return files
+
+
+python_multiline_string_double_re = re.compile(
+  r'"""[^"]*(?:"""|$)', flags=re.MULTILINE)
+python_multiline_string_single_re = re.compile(
+  r"'''[^']*(?:'''|$)", flags=re.MULTILINE)
+automatically_generated_re = re.compile(
+  r'(All changes made in this file will be lost'
+  '|DO NOT (EDIT|delete this file)'
+  '|Generated (at|automatically|data)'
+  '|Automatically generated'
+  '|\Wgenerated\s+(?:\w+\s+)*file\W)', flags=re.IGNORECASE)
+
+def _IsGeneratedFile(header):
+  header = header.upper()
+  if '"""' in header:
+    header = python_multiline_string_double_re.sub('', header)
+  if "'''" in header:
+    header = python_multiline_string_single_re.sub('', header)
+  # First do simple strings lookup to save time.
+  if 'ALL CHANGES MADE IN THIS FILE WILL BE LOST' in header:
+    return True
+  if 'DO NOT EDIT' in header or 'DO NOT DELETE' in header or \
+      'GENERATED' in header:
+    return automatically_generated_re.search(header)
+  return False
+
+
+GENERATED_FILE = 'GENERATED FILE'
+NO_COPYRIGHT = '*No copyright*'
+
+class _CopyrightsScanner(object):
+  _c_comment_re = re.compile(r'''"[^"\\]*(?:\\.[^"\\]*)*"''')
+  _copyright_indicator = r'(?:copyright|copr\.|\xc2\xa9|\(c\))'
+  _full_copyright_indicator_re = \
+    re.compile(r'(?:\W|^)' + _copyright_indicator + r'(?::\s*|\s+)(\w.*)$', \
+                 re.IGNORECASE)
+  _copyright_disindicator_re = \
+    re.compile(r'\s*\b(?:info(?:rmation)?|notice|and|or)\b', re.IGNORECASE)
+
+  def __init__(self):
+    self.max_line_numbers_proximity = 3
+    self.last_a_item_line_number = -200
+    self.last_b_item_line_number = -100
+
+  def _CloseLineNumbers(self, a, b):
+    return 0 <= a - b <= self.max_line_numbers_proximity
+
+  def MatchLine(self, line_number, line):
+    if '"' in line:
+      line = _CopyrightsScanner._c_comment_re.sub('', line)
+    upcase_line = line.upper()
+    # Record '(a)' and '(b)' last occurences in C++ comments.

[mkosiba (inactive), 2014/10/02 13:14:46]

Maybe move/copy the explanation from line 121 to here. It makes it easier to
understand why we're recording (a) and (b)

[mnaganov (inactive), 2014/10/02 13:51:30]

Done.

+    cpp_comment_idx = upcase_line.find('//')
+    if not cpp_comment_idx == -1:

[mkosiba (inactive), 2014/10/02 13:14:47]

cpp_comment_idx != -1 or even '//' in upcase_line

[mnaganov (inactive), 2014/10/02 13:51:30]

We use the value of cpp_comment_idx if it's not -1, so just changed to "!= -1".

+      if upcase_line.find('(A)') > cpp_comment_idx:
+        self.last_a_item_line_number = line_number
+      if upcase_line.find('(B)') > cpp_comment_idx:
+        self.last_b_item_line_number = line_number
+    # Fast bailout, uses the same patterns as _copyright_indicator regexp.
+    if not 'COPYRIGHT' in upcase_line and not 'COPR.' in upcase_line \
+        and not '\xc2\xa9' in upcase_line:
+      c_item_index = upcase_line.find('(C)')
+      if c_item_index == -1:
+        return None
+      # Filter out 'c' used as a list item inside C++ comments.
+      # E.g. "// blah-blah (a) blah\n// blah-blah (b) and (c) blah"
+      if c_item_index > cpp_comment_idx and \
+          self._CloseLineNumbers(line_number,
+                                 self.last_b_item_line_number) and \
+          self._CloseLineNumbers(self.last_b_item_line_number,
+                                 self.last_a_item_line_number):
+        return None
+    copyr = None
+    m = _CopyrightsScanner._full_copyright_indicator_re.search(line)
+    if m and \
+        not _CopyrightsScanner._copyright_disindicator_re.match(m.group(1)):
+      copyr = m.group(0)
+      # Prettify the authorship string.
+      copyr = re.sub(r'([,.])?\s*$/', '', copyr)
+      copyr = re.sub(self._copyright_indicator, '', copyr, flags=re.IGNORECASE)
+      copyr = re.sub(r'^\s+', '', copyr)
+      copyr = re.sub(r'\s{2,}', ' ', copyr)
+      copyr = re.sub(r'\\@', '@', copyr)
+    return copyr
+
+
+def FindCopyrights(root_dir, files_to_scan):
+  """Determines code autorship, and finds generated files.
+  Args:
+    root_dir: The root directory, to which all other paths are relative.
+    files_to_scan: The list of file names to scan.
+  Returns:
+    The list of copyrights associated with each of the files given.
+    If the certain file is generated, the corresponding list consists a single
+    entry -- 'GENERATED_FILE' string. If the file has no copyright info,
+    the corresponding list contains 'NO_COPYRIGHT' string.
+  """
+  copyrights = []
+  for f in files_to_scan:
+    linenum = 0
+    header = ''
+    file_copyrights = []
+    scanner = _CopyrightsScanner()
+    for l in open(os.path.join(root_dir, f), 'r').readlines():

[mkosiba (inactive), 2014/10/02 13:14:46]

umm.. you might run out of fd's if you don't close the file? maybe use 'with' ?

[mnaganov (inactive), 2014/10/02 13:51:30]

That's a really good catch, thanks! Fixed here and also in webview_licenses.py

+      linenum += 1
+      if linenum <= 25:
+        header += l
+      c = scanner.MatchLine(linenum, l)
+      if c:
+        file_copyrights.append(c)
+    if _IsGeneratedFile(header):
+      copyrights.append([GENERATED_FILE])
+    elif file_copyrights:
+      copyrights.append(file_copyrights)
+    else:
+      copyrights.append([NO_COPYRIGHT])
+  return copyrights
+
+
+def FindCopyrightViolations(root_dir, files_to_scan):
+  """Looks for files that are not belong exlusively to the Chromium Authors.
+  Args:
+    root_dir: The root directory, to which all other paths are relative.
+    files_to_scan: The list of file names to scan.
+  Returns:
+    The list of file names that contain non-Chromium copyrights.
+  """
+  copyrights = FindCopyrights(root_dir, files_to_scan)
+  offending_files = []
+  allowed_copyrights_re = re.compile(
+    r'^(?:20[0-9][0-9](?:-20[0-9][0-9])? The Chromium Authors\. '
+    'All rights reserved.*)$')
+  for f, cs in itertools.izip(files_to_scan, copyrights):
+    if cs[0] == GENERATED_FILE or cs[0] == NO_COPYRIGHT:
+      continue
+    for c in cs:
+      if not allowed_copyrights_re.match(c):
+        offending_files.append(os.path.normpath(f))
+        break
+  return offending_files