Bug 1668862 - Add script to extract local modifications to libwebrtc for upstream; r=ng DONTBUILD

Differential Revision: https://phabricator.services.mozilla.com/D92271

dom/media/webrtc/third_party_build/extract-for-git.py

@@ -0,0 +1,102 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+import argparse
+import re
+import subprocess
+
+
+# This script extracts commits that touch third party webrtc code so they can
+# be imported into Git. It filters out commits that are not part of upstream
+# code and rewrites the paths to match upstream. Finally, the commits are
+# combined into a mailbox file that can be applied with `git am`.
+LIBWEBRTC_DIR = 'third_party/libwebrtc/webrtc'
+
+
+def build_commit_list(revset):
+    """Build commit list from the specified revset.
+
+       The revset can be a single revision, e.g. 52bb9bb94661, or a range,
+       e.g. 8c08a5bb8a99::52bb9bb94661, or any other valid revset
+       (check hg help revset). Only commits that touch libwebrtc are included.
+    """
+    res = subprocess.run(['hg', 'log', '-r', revset, '-M', '--template', '{node}\n',
+                          LIBWEBRTC_DIR],
+                         capture_output=True, text=True, cwd='../../../../')
+    return [line.strip() for line in res.stdout.strip().split('\n')]
+
+
+def extract_author_date(sha1):
+    res = subprocess.run(['hg', 'log', '-r', sha1, '--template', '{author}|{date|isodate}'],
+                         capture_output=True, text=True)
+    return res.stdout.split('|')
+
+
+def extract_description(sha1):
+    res = subprocess.run(['hg', 'log', '-r', sha1, '--template', '{desc}'],
+                         capture_output=True, text=True)
+    return res.stdout
+
+
+def extract_commit(sha1):
+    res = subprocess.run(['hg', 'log', '-r', sha1, '-pg', '--template', '\n'],
+                         capture_output=True, text=True)
+    return res.stdout
+
+
+def filter_nonwebrtc(commit):
+    filtered = []
+    skipping = False
+    for line in commit.split('\n'):
+        # Extract only patches affecting libwebrtc, but avoid commits that
+        # touch build, which is tracked by a separate repo, or that affect
+        # moz.build files which are code generated.
+        if (line.startswith('diff --git a/' + LIBWEBRTC_DIR)
+            and not line.startswith('diff --git a/' + LIBWEBRTC_DIR + '/build')
+            and not line.endswith('moz.build')):
+            skipping = False
+        elif line.startswith('diff --git'):
+            skipping = True
+        if not skipping:
+            filtered.append(line)
+    return '\n'.join(filtered)
+
+
+def fixup_paths(commit):
+    return re.sub('third_party/libwebrtc/webrtc/', '', commit)
+
+
+def write_as_mbox(sha1, author, date, description, commit, ofile):
+    # Use same magic date as git format-patch
+    ofile.write('From {} Mon Sep 17 00:00:00 2001\n'.format(sha1))
+    ofile.write('From: {}\n'.format(author))
+    ofile.write('Date: {}\n'.format(date))
+    description = description.split('\n')
+    ofile.write('Subject: {}\n'.format(description[0]))
+    ofile.write('\n'.join(description[1:]))
+    ofile.write('\nMercurial Revision: https://hg.mozilla.org/mozilla-central/rev/{}\n'
+                .format(sha1))
+    ofile.write(commit)
+    ofile.write('\n')
+    ofile.write('\n')
+
+
+if __name__ == '__main__':
+    commits = []
+    parser = argparse.ArgumentParser(description='Format commits for upstream libwebrtc')
+    parser.add_argument('revsets', metavar='revset', type=str, nargs='+',
+                        help='A revset to process')
+    args = parser.parse_args()
+
+    for revset in args.revsets:
+        commits.extend(build_commit_list(revset))
+
+    with open('mailbox.patch', 'w') as ofile:
+        for sha1 in commits:
+            author, date = extract_author_date(sha1)
+            description = extract_description(sha1)
+            filtered_commit = filter_nonwebrtc(extract_commit(sha1))
+            if len(filtered_commit) == 0:
+                continue
+            fixedup_commit = fixup_paths(filtered_commit)
+            write_as_mbox(sha1, author, date, description, fixedup_commit, ofile)