util: add update-copyright utility to update copyright on commits

The utility can automatically update copyright for the chosen
organization on all files touched in the selected range of git commits.

Change-Id: I4e1803e53f4530f88fb344f56e08ea29fbfcd41d
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/35535
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>

CONTRIBUTING.md

@@ -203,7 +203,10 @@ both tags and in the author field of the changeset.
 For significant changes, authors are encouraged to add copyright information
 and their names at the beginning of the file. The main purpose of the author
 names on the file is to track who is most knowledgeable about the file (e.g.,
-who has contributed a significant amount of code to the file).
+who has contributed a significant amount of code to the file). The
+`util/update-copyright.py` helper script can help to keep your copyright dates
+up-to-date when you make further changes to files which already have your
+copyright but with older dates.
 
 Note: If you do not follow these guidelines, the gerrit review site will
 automatically reject your patch.

util/update-copyright.py

@@ -0,0 +1,141 @@
+#!/usr/bin/env python
+
+# Copyright (c) 2020 ARM Limited
+# All rights reserved
+#
+# The license below extends only to copyright in the software and shall
+# not be construed as granting a license to any other intellectual
+# property including but not limited to intellectual property relating
+# to a hardware implementation of the functionality of the software
+# licensed hereunder.  You may use the software subject to the license
+# terms below provided that you ensure that this notice is replicated
+# unmodified and in its entirety in all distributions of the software,
+# modified or unmodified, in source code or in binary form.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met: redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer;
+# redistributions in binary form must reproduce the above copyright
+# notice, this list of conditions and the following disclaimer in the
+# documentation and/or other materials provided with the distribution;
+# neither the name of the copyright holders nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+import argparse
+import datetime
+import subprocess
+import sys
+
+import git_filter_repo
+
+import update_copyright
+
+parser = argparse.ArgumentParser(description=
+"""Update copyright headers on files of a range of commits.
+
+This can be used to easily update copyright headers at once on an entire
+patchset before submitting.
+
+Only files touched by the selected commits are updated.
+
+Only existing copyrights for the selected holder are updated, new
+notices are never automatically added if not already present.
+
+The size of the changes is not taken into account, every touched file gets
+updated. If you want to undo that for a certain file because the change to
+it is trivial, you need to manually rebase and undo the copyright change
+for that file.
+
+Example usage with an organization alias such as `arm`:
+
+```
+python3 -m pip install --user --requirement \
+  gem5/util/update_copyright/requirements.txt
+./update-copyright.py -o arm HEAD~3
+```
+
+The above would act on the 3 last commits (HEAD~2, HEAD~ and HEAD),
+leaving HEAD~3 unchanged, and doing updates such as:
+
+```
+- * Copyright (c) 2010, 2012-2013, 2015,2017-2019 ARM Limited
++ * Copyright (c) 2010, 2012-2013, 2015,2017-2020 ARM Limited
+```
+
+If the organization is not in the alias list, you can also explicitly give
+the organization string as in:
+
+```
+./update-copyright.py HEAD~3 'ARM Limited'
+```
+
+which is equivalent to the previous invocation.
+""",
+    formatter_class=argparse.RawTextHelpFormatter,
+)
+parser.add_argument('start',
+        nargs='?',
+        help="The commit before the last commit to be modified")
+parser.add_argument('org-string',
+        nargs='?',
+        help="Copyright holder name")
+parser.add_argument('-o', '--org', choices=('arm',),
+        help="Alias for known organizations")
+args = parser.parse_args()
+
+def error(msg):
+    print('error: ' + msg, file=sys.stderr)
+    sys.exit(1)
+
+# The existing safety checks are too strict, so we just disable them
+# with force, and do our own checks to not overwrite uncommited changes
+# checks.
+# https://github.com/newren/git-filter-repo/issues/159
+if subprocess.call(['git', 'diff', '--staged', '--quiet']):
+    error("uncommitted changes")
+if subprocess.call(['git', 'diff', '--quiet']):
+    error("unstaged changes")
+
+# Handle CLI arguments.
+if args.start is None:
+    error("the start argument must be given")
+if args.org is None and getattr(args, 'org-string') is None:
+    error("either --org or org-string must be given")
+if args.org is not None and getattr(args, 'org-string') is not None:
+    error("both --org and org-string given")
+if args.org is not None:
+    org_bytes = update_copyright.org_alias_map[args.org]
+else:
+    org_bytes = getattr(args, 'org-string').encode()
+
+# Call git_filter_repo.
+# Args deduced from:
+# print(git_filter_repo.FilteringOptions.parse_args(['--refs', 'HEAD',
+# '--force'], error_on_empty=False))
+filter_repo_args = git_filter_repo.FilteringOptions.default_options()
+filter_repo_args.force = True
+filter_repo_args.partial = True
+filter_repo_args.refs = ['{}..HEAD'.format(args.start)]
+filter_repo_args.repack=False
+filter_repo_args.replace_refs='update-no-add'
+def blob_callback(blob, callback_metadata, org_bytes):
+    blob.data = update_copyright.update_copyright(blob.data,
+        datetime.datetime.now().year, org_bytes)
+git_filter_repo.RepoFilter(
+    filter_repo_args,
+    blob_callback=lambda x, y: blob_callback( x, y, org_bytes)
+).run()

util/update_copyright/__init__.py

@@ -0,0 +1,87 @@
+# Copyright (c) 2020 ARM Limited
+# All rights reserved
+#
+# The license below extends only to copyright in the software and shall
+# not be construed as granting a license to any other intellectual
+# property including but not limited to intellectual property relating
+# to a hardware implementation of the functionality of the software
+# licensed hereunder.  You may use the software subject to the license
+# terms below provided that you ensure that this notice is replicated
+# unmodified and in its entirety in all distributions of the software,
+# modified or unmodified, in source code or in binary form.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met: redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer;
+# redistributions in binary form must reproduce the above copyright
+# notice, this list of conditions and the following disclaimer in the
+# documentation and/or other materials provided with the distribution;
+# neither the name of the copyright holders nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""
+Utilities to parse and modify copyright headers in gem5 source.
+"""
+
+import re
+
+org_alias_map = {
+    'arm': b'ARM Limited',
+    'uc': b'The Regents of the University of California',
+}
+
+_update_copyright_year_regexp = re.compile(b'(.*?)([0-9]+)$')
+
+def _update_copyright_years(m, cur_year, org_bytes):
+    '''
+    Does e.g.: b'2016, 2018-2019' -> b'2016, 2018-2020'.
+
+    :param m: match containing only the years part of the string
+    :type m: re.Match
+    :param cur_year: the current year to update the copyright to
+    :type cur_year: int
+    :return: the new years part of the string
+    :rtype: bytes
+    '''
+    global _update_copyright_year_regexp
+    cur_year_bytes = str(cur_year).encode()
+    m = _update_copyright_year_regexp.match(m.group(1))
+    years_prefix = m.group(1)
+    old_year_bytes = m.group(2)
+    old_year = int(old_year_bytes.decode())
+    if old_year == cur_year:
+        new_years_string = old_year_bytes
+    elif old_year == cur_year - 1:
+        if len(years_prefix) > 0 and years_prefix[-1:] == b'-':
+            new_years_string = cur_year_bytes
+        else:
+            new_years_string = old_year_bytes + b'-' + cur_year_bytes
+    else:
+        new_years_string = old_year_bytes + b', ' + cur_year_bytes
+    new_years_string = years_prefix + new_years_string
+    return b' Copyright (c) %b %b\n' % (new_years_string, org_bytes)
+
+def update_copyright(data, cur_year, org_bytes):
+    update_copyright_regexp = re.compile(
+        b' Copyright \\(c\\) ([0-9,\- ]+) ' + org_bytes + b'\n',
+        re.IGNORECASE
+    )
+    return update_copyright_regexp.sub(
+        lambda m: _update_copyright_years(m, cur_year, org_bytes),
+        data,
+        count=1,
+    )

util/update_copyright/requirements.txt

@@ -0,0 +1 @@
+git-filter-repo==2.28.0

util/update_copyright/test/test_copyright.py

@@ -0,0 +1,86 @@
+# Copyright (c) 2020 ARM Limited
+# All rights reserved
+#
+# The license below extends only to copyright in the software and shall
+# not be construed as granting a license to any other intellectual
+# property including but not limited to intellectual property relating
+# to a hardware implementation of the functionality of the software
+# licensed hereunder.  You may use the software subject to the license
+# terms below provided that you ensure that this notice is replicated
+# unmodified and in its entirety in all distributions of the software,
+# modified or unmodified, in source code or in binary form.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met: redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer;
+# redistributions in binary form must reproduce the above copyright
+# notice, this list of conditions and the following disclaimer in the
+# documentation and/or other materials provided with the distribution;
+# neither the name of the copyright holders nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+import unittest
+
+import update_copyright
+
+class TestUpdateCopyright(unittest.TestCase):
+    def update_arm_copyright(self, data, cur_year):
+        return update_copyright.update_copyright(
+                data, cur_year,
+                update_copyright.org_alias_map['arm'])
+    def update_uc_copyright(self, data, cur_year):
+        return update_copyright.update_copyright(
+                data, cur_year,
+                update_copyright.org_alias_map['uc'])
+    def test_cpp(self):
+        self.assertEqual(self.update_arm_copyright(
+                b' * Copyright (c) 2019 ARM Limited\n', 2020),
+                b' * Copyright (c) 2019-2020 ARM Limited\n')
+        self.assertEqual(self.update_uc_copyright(
+b' * Copyright (c) 2019 The Regents of the University of California\n', 2020),
+b' * Copyright (c) 2019-2020 The Regents of the University of California\n')
+    def test_python(self):
+        self.assertEqual(self.update_arm_copyright(
+                b'# Copyright (c) 2019 ARM Limited\n', 2020),
+                b'# Copyright (c) 2019-2020 ARM Limited\n')
+    def test_multiline(self):
+        self.assertEqual(self.update_arm_copyright(
+                b'''/*
+* Copyright (c) 2019 ARM Limited
+* All rights reserved.
+''', 2020),
+        b'''/*
+* Copyright (c) 2019-2020 ARM Limited
+* All rights reserved.
+''',
+                )
+    def test_comma(self):
+        self.assertEqual(self.update_arm_copyright(
+                b'# Copyright (c) 2018 ARM Limited\n', 2020),
+                b'# Copyright (c) 2018, 2020 ARM Limited\n')
+    def test_extend_dash(self):
+        self.assertEqual(self.update_arm_copyright(
+                b'# Copyright (c) 2018-2019 ARM Limited\n', 2020),
+                b'# Copyright (c) 2018-2020 ARM Limited\n')
+    def test_comma_and_dash_extend(self):
+        self.assertEqual(self.update_arm_copyright(
+                b'# Copyright (c) 2016, 2018-2019 ARM Limited\n', 2020),
+                b'# Copyright (c) 2016, 2018-2020 ARM Limited\n')
+    def test_standardize_case(self):
+        self.assertEqual(self.update_arm_copyright(
+                b'# Copyright (c) 2020 Arm Limited\n', 2020),
+                b'# Copyright (c) 2020 ARM Limited\n')