Improve revision handling.

tools/revstamp.py

@@ -0,0 +1,32 @@
+#! /usr/bin/env python3
+# Copyright 2023 Bradley D. Nelson
+#
+# 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 os
+import subprocess
+import sys
+
+base_path = sys.argv[1]
+revision_file = sys.argv[2]
+revshort_file = sys.argv[3]
+
+revision = subprocess.check_output('git rev-parse HEAD ' + base_path, shell=True).splitlines()[0]
+revshort = revision[:7]
+
+if not os.path.exists(revision_file) or open(revision_file).read() != revision:
+  with open(revision_file, 'wb') as fh:
+    fh.write(revision)
+if not os.path.exists(revshort_file) or open(revshort_file).read() != revshort:
+  with open(revshort_file, 'wb') as fh:
+    fh.write(revshort)