Add a ktfmt.py wrapper around ktfmt.jar

This CL adds a wrapper script around ktfmt.jar to easily format or check
some Kotlin files folders, optionally filtering only the files in an
include list. This will be used by a preupload hook to check the Kotlin
files modified in a commit.

Bug: 235461679
Test: Manual
Change-Id: I8a1d3eb7e00c7f7fa95a57d6df98bbe09c065c29

1 files changed, 135 insertions, 0 deletions

diff --git a/ktfmt.py b/ktfmt.py
new file mode 100755
index 0000000..9cfbd13
--- /dev/null
+++ b/ktfmt.py
@@ -0,0 +1,135 @@
+#!/usr/bin/env python3
+
+#
+# Copyright 2022, 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.
+#
+"""Script to format or check Kotlin files."""
+
+import argparse
+import os
+import subprocess
+import sys
+
+
+def main():
+  parser = argparse.ArgumentParser(
+      'Format Kotlin files or check that they are correctly formatted.')
+  parser.add_argument(
+      '--check',
+      '-c',
+      action='store_true',
+      default=False,
+      help='Perform a format check instead of formatting.')
+  parser.add_argument(
+      '--includes_file',
+      '-i',
+      default='',
+      help='The file containing the Kotlin files and directories that should be formatted/checked.'
+  )
+  parser.add_argument(
+      'files',
+      nargs='*',
+      help='The files to format or check. If --include_file is specified, only the files at their intersection will be formatted/checked.'
+  )
+  args = parser.parse_args()
+
+  ktfmt_args = ['--kotlinlang-style']
+
+  check = args.check
+  if check:
+    ktfmt_args += ['--set-exit-if-changed', '--dry-run']
+
+  kt_files = []
+  for file in args.files:
+    if os.path.isdir(file):
+      for root, dirs, files in os.walk(file):
+        for f in files:
+          if is_kotlin_file(f):
+            kt_files += [os.path.join(root, f)]
+
+    if is_kotlin_file(file):
+      kt_files += [file]
+
+  # Only format/check files from the includes list.
+  includes_file = args.includes_file
+  if kt_files and includes_file:
+    f = open(includes_file, 'r')
+
+    lines = f.read().splitlines()
+    included_files = set()
+    included_dirs = []
+    for line in lines:
+      if is_kotlin_file(line):
+        included_files.add(line)
+      else:
+        included_dirs += [line]
+
+    kt_files = [
+        kt_file for kt_file in kt_files
+        if kt_file in included_files or is_included(kt_file, included_dirs)
+    ]
+
+  # No need to start ktfmt if there are no files to check/format.
+  if not kt_files:
+    sys.exit(0)
+
+  ktfmt_args += kt_files
+
+  dir = os.path.normpath(os.path.dirname(__file__))
+  ktfmt_jar = os.path.join(
+      dir, '../../prebuilts/build-tools/common/framework/ktfmt.jar')
+
+  ktlint_env = os.environ.copy()
+  ktlint_env['JAVA_CMD'] = 'java'
+  try:
+    process = subprocess.Popen(
+        ['java', '-jar', ktfmt_jar] + ktfmt_args,
+        stdout=subprocess.PIPE,
+        env=ktlint_env)
+    stdout, _ = process.communicate()
+    code = process.returncode
+    if check and code != 0:
+      print(
+          '**********************************************************************'
+      )
+      print(
+          'Some Kotlin files are not properly formatted. Run the following command to format them:\n\n'
+      )
+      script_path = os.path.normpath(__file__)
+      incorrect_files = stdout.decode('utf-8').splitlines()
+      print('$ ' + script_path + ' ' + ' '.join(incorrect_files) + '\n')
+      print(
+          '**********************************************************************'
+      )
+      sys.exit(code)
+    else:
+      sys.exit(0)
+  except OSError as e:
+    print('Error running ktfmt')
+    sys.exit(1)
+
+
+def is_kotlin_file(name):
+  return name.endswith('.kt') or name.endswith('.kts')
+
+
+def is_included(file, dirs):
+  for dir in dirs:
+    if file.startswith(dir):
+      return True
+
+
+if __name__ == '__main__':
+  main()