repo-patch: Download patch files from Gerrit

This commit adds a utility to download multiple patch files from Gerrit
by a change list query.

Test: repo_patch.py -g [gerrit] [query]
Change-Id: I3685c48d2ea4e5a9fa1915c4e31bc6ebb2d4ed97

tools/repo_pull/gerrit.py

@@ -19,6 +19,7 @@
 from __future__ import print_function
 
 import argparse
+import base64
 import json
 import os
 import sys
@@ -158,6 +159,19 @@ def set_review(url_opener, gerrit_url, change_id, labels, message):
         response_file.close()
 
 
+def get_patch(url_opener, gerrit_url, change_id, revision_id='current'):
+    """Download the patch file."""
+
+    url = '{}/a/changes/{}/revisions/{}/patch'.format(
+        gerrit_url, change_id, revision_id)
+
+    response_file = url_opener.open(url)
+    try:
+        return base64.b64decode(response_file.read())
+    finally:
+        response_file.close()
+
+
 def _parse_args():
     """Parse command line options."""
     parser = argparse.ArgumentParser()

tools/repo_pull/repo_patch.py

@@ -0,0 +1,68 @@
+#!/usr/bin/env python3
+
+#
+# Copyright (C) 2018 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+"""A command line utility to download multiple patch files of change lists from
+Gerrit."""
+
+from __future__ import print_function
+
+from gerrit import create_url_opener_from_args, query_change_lists, get_patch
+
+import argparse
+import os
+
+
+def _parse_args():
+    """Parse command line options."""
+    parser = argparse.ArgumentParser()
+
+    parser.add_argument('query', help='Change list query string')
+    parser.add_argument('-g', '--gerrit', required=True,
+                        help='Gerrit review URL')
+
+    parser.add_argument('--gitcookies',
+                        default=os.path.expanduser('~/.gitcookies'),
+                        help='Gerrit cookie file')
+    parser.add_argument('--limits', default=1000,
+                        help='Max number of change lists')
+
+    return parser.parse_args()
+
+
+def main():
+    args = _parse_args()
+
+    # Query change lists
+    url_opener = create_url_opener_from_args(args)
+    change_lists = query_change_lists(
+        url_opener, args.gerrit, args.query, args.limits)
+
+    # Download patch files
+    num_changes = len(change_lists)
+    num_changes_width = len(str(num_changes))
+    for i, change in enumerate(change_lists, start=1):
+        print('{:>{}}/{} | {} {}'.format(
+                i, num_changes_width, num_changes, change['_number'],
+                change['subject']))
+
+        patch_file = get_patch(url_opener, args.gerrit, change['id'])
+        with open('{}.patch'.format(change['_number']), 'wb') as output_file:
+            output_file.write(patch_file)
+
+if __name__ == '__main__':
+    main()