util: Add maintainer tools to create upstream patches

This changeset adds a maintainer script, create_patches.sh, that can
be used to prepare for upstream from a git repository. The script can
be used to generate patches in Mercurial or git format. The commit
messages in the exported patches are all filtered, see
upstream_msg_filter.sed, to ensure that irrelevant meta data isn't
included in the upstream commit.

Kudos to Curtis Dunham and Nikos Nikoleris for reviews and usability
enhancements for earlier versions of this patch.

Change-Id: Ia4cd089a32834b5e046ef58c0a173ca285b77bca
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Curtis Dunham <curtis.dunham@arm.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>

3 files changed, 360 insertions, 0 deletions

diff --git a/util/maint/create_patches.sh b/util/maint/create_patches.sh
new file mode 100755
index 000000000..7c1655f78
--- /dev/null
+++ b/util/maint/create_patches.sh
@@ -0,0 +1,177 @@
+#!/bin/bash
+#
+# Copyright (c) 2016 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.
+#
+# Authors: Andreas Sandberg
+#
+
+set -e
+
+REL_SCRIPT_DIR=`dirname "$0"`
+SCRIPT_NAME=`basename "$0"`
+SCRIPT_DIR=$(cd "$REL_SCRIPT_DIR" && echo "$(pwd -P)")
+MSG_FILTER="$SCRIPT_DIR"/upstream_msg_filter.sed
+CONV_HG="$SCRIPT_DIR"/git-patch-to-hg-patch
+
+PATCH_DIR="./patches/"
+UPSTREAM="upstream/master"
+PATCH_FORMAT=
+
+usage()
+{
+    cat <<EOF
+$SCRIPT_NAME [OPTION]...  [BRANCH]
+Format a patch series suitable for upstream consumption.
+
+Options:
+  -u BRANCH      Upstream branch
+  -d DIR         Patch directory
+  -f FMT         Patch format (hg or git)
+  -h             Show this help string.
+
+This script creates a series of patches suitable from upstream
+consumption from a git branch. By default, the script works on the
+currently checked out branch (HEAD). When invoked, the script executes
+the following operations in order:
+
+  1. Rebase the patches in the current branch onto the upstream
+     branch.
+  2. Filter commit messages.
+  3. Generate a set of patches in git format or Mercurial format.
+EOF
+}
+
+branch_exists()
+{
+    git rev-parse --verify -q "$1" > /dev/null
+}
+
+while getopts ":u:d:f:h" OPT; do
+    case $OPT in
+        d)
+            PATCH_DIR="$OPTARG"
+            ;;
+        u)
+            UPSTREAM="$OPTARG"
+            ;;
+        f)
+            PATCH_FORMAT="$OPTARG"
+            ;;
+        h)
+            usage
+            exit 0
+            ;;
+
+        \?)
+            echo "$0: invalid option --  '$OPTARG'" >&2
+            echo "Try '$0 -h' for more information." >&2
+            exit 1
+            ;;
+        :)
+            echo "$0: option requires an argument -- '$OPTARG'" >&2
+            exit 1
+            ;;
+        *)
+            echo "Unhandled getopt return:" >&2
+            echo "OPT: $OPT" >&2
+            echo "OPTARG: $OPTARG" >&2
+            exit 1
+    esac
+done
+
+
+shift $((OPTIND - 1))
+
+BRANCH="${1:-HEAD}"
+
+case "$PATCH_FORMAT" in
+    git|hg)
+        ;;
+
+    "")
+        echo "Error: No patch format specified" >&2
+        exit 1
+        ;;
+
+    *)
+        echo "Error: Illegal patch format specified: '$PATCH_FORMAT'" >&2
+        exit 1
+esac
+
+
+if ! branch_exists "$BRANCH"; then
+    echo "Error: Patch branch '$BRANCH' doesn't exist" 1>&2
+    exit 2
+fi
+
+if ! branch_exists "$UPSTREAM"; then
+    echo "Error: Upstream branch '$UPSTREAM' doesn't exist." 1>&2
+    exit 2
+fi
+
+SHA_PATCHES=`git rev-parse "$BRANCH"`
+OLD_BRANCH=`git symbolic-ref --short -q HEAD`
+SHA_UPSTREAM=`git rev-parse "$UPSTREAM"`
+
+echo "Upstream branch: $UPSTREAM"
+echo "Patch directory: $PATCH_DIR"
+
+echo "Preparing detached head..."
+git checkout -q --detach "$SHA_PATCHES"
+
+# Create an exit trap to checkout the old branch when we're done
+exit_trap() {
+    git checkout -q "$OLD_BRANCH"
+}
+trap exit_trap EXIT
+
+echo "Rebasing onto upstream master..."
+git rebase "$UPSTREAM"
+
+echo "Filtering commit messages..."
+git filter-branch -f \
+    --msg-filter "$MSG_FILTER" \
+    "$SHA_UPSTREAM"..HEAD > /dev/null
+
+echo "Creating patches..."
+git format-patch -p -o "$PATCH_DIR" "$UPSTREAM"
+
+if [ "$PATCH_FORMAT" == "hg" ]; then
+    echo "Converting patches..."
+    for P in "$PATCH_DIR"/*.patch; do
+        "$CONV_HG" $P
+    done
+fi
diff --git a/util/maint/git-patch-to-hg-patch b/util/maint/git-patch-to-hg-patch
new file mode 100755
index 000000000..6819cfcce
--- /dev/null
+++ b/util/maint/git-patch-to-hg-patch
@@ -0,0 +1,137 @@
+#!/usr/bin/env python
+#
+# This file originated from the moz-git-tools repo on GitHub
+# (https://github.com/mozilla/moz-git-tools), which contains the
+# following LICENSE notice:
+#
+# <quote>
+# Except for git-new-workdir, which is covered under GPLv2, the code
+# in this repository is placed into the public domain via CC0.
+#
+# http://creativecommons.org/publicdomain/zero/1.0/legalcode
+# </quote>
+
+r"""Git format-patch to hg importable patch.
+
+(Who knew this was so complicated?)
+
+>>> process(StringIO('From 3ce1ccc06 Mon Sep 17 00:00:00 2001\nFrom: fromuser\nSubject: subject\n\nRest of patch.\nMore patch.\n'))
+'# HG changeset patch\n# User fromuser\n\nsubject\n\nRest of patch.\nMore patch.\n'
+
+>>> process(StringIO('From: fromuser\nSubject: A very long subject line.  Lorem ipsum dolor sit amet, consectetur adipiscing elit. Morbi faucibus, arcu sit amet\n\nRest of patch.\nMore patch.\n'))
+'# HG changeset patch\n# User fromuser\n\nA very long subject line.  Lorem ipsum dolor sit amet, consectetur adipiscing elit. Morbi faucibus, arcu sit amet\n\nRest of patch.\nMore patch.\n'
+
+>>> process(StringIO('From: f\nSubject: =?UTF-8?q?Bug=20655877=20-=20Dont=20treat=20SVG=20text=20frames=20?= =?UTF-8?q?as=20being=20positioned.=20r=3D=3F?=\n\nPatch.'))
+'# HG changeset patch\n# User f\n\nBug 655877 - Dont treat SVG text frames as being positioned. r=?\n\nPatch.'
+"""
+
+# Original author: bholley
+
+import sys
+import re
+import fileinput
+import email, email.parser, email.header, email.utils
+import math
+from cStringIO import StringIO
+from itertools import takewhile
+
+def decode_header(hdr_string):
+  r"""Clean up weird encoding crap.
+
+  >>> clean_header('[PATCH] =?UTF-8?q?Bug=20655877=20r=3D=3F?=')
+  '[PATCH] Bug 655877 r=?'
+  """
+  rv = []
+  hdr = email.header.Header(hdr_string, maxlinelen=float('inf'))
+  for (part, encoding) in email.header.decode_header(hdr):
+    if encoding is None:
+      rv.append(part)
+    else:
+      rv.append(part.decode(encoding).encode('utf-8'))
+  return ' '.join(rv)
+
+def clean_header(hdr_string):
+  r"""Transform a header split over many lines into a header split only where
+  linebreaks are intended.  This is important because hg cares about the first
+  line of the commit message.
+
+  Also clean up weird encoding crap.
+
+  >>> clean_header('Foo\n bar\n baz')
+  'Foo bar baz'
+  >>> clean_header('Foo\n bar\nSpam\nEggs')
+  'Foo bar\nSpam\nEggs'
+  """
+
+  lines = []
+  curline = ''
+  for line in decode_header(hdr_string).split('\n'):
+    if not line.startswith(' '):
+      lines.append(curline)
+      curline = ''
+    curline += line
+  lines.append(curline)
+  return '\n'.join(lines[1:])
+
+def process(git_patch_file):
+  parser = email.parser.Parser()
+  msg = parser.parse(git_patch_file)
+  from_hdr = clean_header(msg['From'])
+  commit_title = clean_header(msg['subject'])
+  if not len(commit_title) or not len(from_hdr):
+    sys.stderr.write("%s does not look like a valid git patch file, skipping\n"
+                     % git_patch_file.name)
+    return
+
+  parsed_from = email.utils.parseaddr(from_hdr)
+  nuke_prefix = r"\[PATCH( \d+/\d+)?\] "
+  match = re.match(nuke_prefix, commit_title)
+  if match:
+    commit_title = commit_title[match.end():]
+
+  patch_body = msg.get_payload()
+
+  # git format-patch wraps the diff (including trailing whitespace):
+  #   ---
+  #   <diff>
+  #   --
+  #   2.0.3
+  # This doesn't hurt parsing the diff at all, but the version number is
+  # nonsense once the git specific items have been stripped
+  patch_body = re.sub(r'--\s?\n[0-9\.]+\n$', '', patch_body)
+
+  return '\n'.join(['# HG changeset patch',
+                    '# User %s <%s>' % parsed_from,
+                    '',
+                    commit_title,
+                    '',
+                    patch_body])
+
+if __name__ == "__main__":
+  if len(sys.argv) > 1 and sys.argv[1] == '--test':
+    import doctest
+    doctest.testmod()
+    sys.exit(0)
+
+  # If there were no arguments, do stdin->stdout.
+  filelist = sys.argv[1:]
+  if not filelist:
+    lines = process(sys.stdin)
+    sys.stdout.writelines(lines)
+    sys.exit(0)
+
+  # Otherwise, we take a list of files.
+  for filename in filelist:
+
+    # Read the lines.
+    f = open(filename, 'r')
+    lines = process(f)
+    f.close()
+
+    # Process.
+
+    if lines:
+      # Write them back to the same file.
+      f = open(filename, 'w')
+      f.writelines(lines)
+      f.close()
diff --git a/util/maint/upstream_msg_filter.sed b/util/maint/upstream_msg_filter.sed
new file mode 100755
index 000000000..5fe01cfcb
--- /dev/null
+++ b/util/maint/upstream_msg_filter.sed
@@ -0,0 +1,46 @@
+#!/bin/sed -f
+#
+# Copyright (c) 2016 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.
+#
+# Authors: Andreas Sandberg
+
+# This script removes metadata tags that should be considered internal
+# to a specific gerrit instance.
+
+/Reviewed-on:/d;
+/Tested-by:/d;
+/Copyright-Check:/d;
+/Style-Check:/d;