meson: Add a script to extract the cmd line used for meson

Upstream I'm persuing a more comprehensive solution, but this should
prove a suitable stop-gap measure in the meantime.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=109325
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Acked-by: Eric Engestrom <eric@engestrom.ch>
Acked-by: Tapani Pälli <tapani.palli@intel.com>

diff --git a/bin/meson-cmd-extract.py b/bin/meson-cmd-extract.py
new file mode 100755 (executable)
index 0000000..61d6b40
--- /dev/null
+++ b/bin/meson-cmd-extract.py
@@ -0,0 +1,77 @@
+#!/usr/bin/env python3
+# Copyright © 2019 Intel Corporation
+
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+
+"""This script reads a meson build directory and gives back the command line it
+was configured with.
+
+This only works for meson 0.49.0 and newer.
+"""
+
+import argparse
+import configparser
+import pathlib
+import sys
+
+
+def parse_args() -> argparse.Namespace:
+    """Parse arguments."""
+    parser = argparse.ArgumentParser()
+    parser.add_argument(
+        'build_dir',
+        help='Path the meson build directory')
+    args = parser.parse_args()
+    return args
+
+
+def load_config(path: pathlib.Path) -> configparser.ConfigParser:
+    """Load config file."""
+    conf = configparser.ConfigParser()
+    with path.open() as f:
+        conf.read_file(f)
+    return conf
+
+
+def build_cmd(conf: configparser.ConfigParser) -> str:
+    """Rebuild the command line."""
+    args = []
+    for k, v in conf['options'].items():
+        if ' ' in v:
+            args.append(f'-D{k}="{v}"')
+        else:
+            args.append(f'-D{k}={v}')
+    return ' '.join(args)
+
+
+def main():
+    args = parse_args()
+    path = pathlib.Path(args.build_dir, 'meson-private', 'cmd_line.txt')
+    if not path.exists():
+        print('Cannot find the necessary file to rebuild command line. '
+              'Is your meson version >= 0.49.0?', file=sys.stderr)
+        sys.exit(1)
+
+    conf = load_config(path)
+    cmd = build_cmd(conf)
+    print(cmd)
+
+
+if __name__ == '__main__':
+    main()