renderdiff: add initial code for updating goldens (#8349)

- Code for parsing tag in commit message
- Add placeholder for pulling and updating goldens in the script.

test/renderdiff/src/utils.py

@@ -0,0 +1,68 @@
+# Copyright (C) 2024 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.
+
+import subprocess
+import os
+import argparse
+import sys
+
+def execute(cmd,
+            cwd=None,
+            capture_output=True,
+            stdin=None,
+            env=None,
+            raise_errors=False):
+  in_env = os.environ
+  in_env.update(env if env else {})
+  home = os.environ['HOME']
+  if f'{home}/bin' not in in_env['PATH']:
+    in_env['PATH'] = in_env['PATH'] + f':{home}/bin'
+
+  stdout = subprocess.PIPE if capture_output else sys.stdout
+  stderr = subprocess.PIPE if capture_output else sys.stdout
+  output = ''
+  err_output = ''
+  return_code = -1
+  kwargs = {
+      'cwd': cwd,
+      'env': in_env,
+      'stdout': stdout,
+      'stderr': stderr,
+      'stdin': stdin,
+      'universal_newlines': True
+  }
+  if capture_output:
+    process = subprocess.Popen(cmd.split(' '), **kwargs)
+    output, err_output = process.communicate()
+    return_code = process.returncode
+  else:
+    return_code = subprocess.call(cmd.split(' '), **kwargs)
+
+  if return_code:
+    # Error
+    if raise_errors:
+      raise subprocess.CalledProcessError(return_code, cmd)
+  if output:
+    if type(output) != str:
+      try:
+        output = output.decode('utf-8').strip()
+      except UnicodeDecodeError as e:
+        print('cannot decode ', output, file=sys.stderr)
+  return return_code, (output if return_code == 0 else err_output)
+
+class ArgParseImpl(argparse.ArgumentParser):
+  def error(self, message):
+    sys.stderr.write('error: %s\n' % message)
+    self.print_help()
+    sys.exit(1)