build-sys: create Makefile-man.am automatically

man rules were repeating the same information in too many places,
which was error prone. Those rules can be easily generated from .xml
files. For efficiency and because python is not a required dependency,
Makefile-man.am is only regenerated when requested with

  make update-man-list

If no metadata in man/*.xml changed, this file should not change. So
only when a new man page or a new alias is added, this file should
show up in 'git diff'. The change should then be committed.

If the support for building from git without python was dropped, we
could drop Makefile-man.am from version control. This would also
increase the partial build time (since more stuff would be rebuild
whenever sources in man/*.xml would be modified), so it would probably
wouldn't be worth it.

1 files changed, 92 insertions, 0 deletions

diff --git a/make-man-rules.py b/make-man-rules.py
new file mode 100644
index 000000000..b88b43ac3
--- /dev/null
+++ b/make-man-rules.py
@@ -0,0 +1,92 @@
+#  -*- Mode: python; coding: utf-8; indent-tabs-mode: nil -*- */
+#
+#  This file is part of systemd.
+#
+#  Copyright 2013 Zbigniew Jędrzejewski-Szmek
+#
+#  systemd is free software; you can redistribute it and/or modify it
+#  under the terms of the GNU Lesser General Public License as published by
+#  the Free Software Foundation; either version 2.1 of the License, or
+#  (at your option) any later version.
+#
+#  systemd is distributed in the hope that it will be useful, but
+#  WITHOUT ANY WARRANTY; without even the implied warranty of
+#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+#  Lesser General Public License for more details.
+#
+#  You should have received a copy of the GNU Lesser General Public License
+#  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+
+from __future__ import print_function
+import xml.etree.ElementTree as tree
+import collections
+import sys
+
+SECTION = '''\
+MANPAGES += \\
+	{manpages}
+MANPAGES_ALIAS += \\
+	{aliases}
+{rules}
+'''
+
+CONDITIONAL = '''\
+if {conditional}
+''' \
++ SECTION + \
+'''\
+endif
+'''
+
+HEADER = '''\
+# Do not edit. Generated by make-man-rules.py.
+# Regenerate with 'make update-man-list'.
+
+'''
+
+def man(page, number):
+    return 'man/{}.{}'.format(page, number)
+
+def add_rules(rules, name):
+    xml = tree.parse(name)
+    # print('parsing {}'.format(name), file=sys.stderr)
+    conditional = xml.getroot().get('conditional') or ''
+    rulegroup = rules[conditional]
+    refmeta = xml.find('./refmeta')
+    title = refmeta.find('./refentrytitle').text
+    number = refmeta.find('./manvolnum').text
+    refnames = xml.findall('./refnamediv/refname')
+    target = man(refnames[0].text, number)
+    if title != refnames[0].text:
+        raise ValueError('refmeta and refnamediv disagree: ' + name)
+    for refname in refnames:
+        assert all(refname not in group
+                   for group in rules.values()), "duplicate page name"
+        alias = man(refname.text, number)
+        rulegroup[alias] = target
+        # print('{} => {} [{}]'.format(alias, target, conditional), file=sys.stderr)
+
+def create_rules(*xml_files):
+    " {conditional => {alias-name => source-name}} "
+    rules = collections.defaultdict(dict)
+    for name in xml_files:
+        add_rules(rules, name)
+    return rules
+
+def mjoin(files):
+    return ' \\\n\t'.join(sorted(files) or '#')
+
+def make_makefile(rules):
+    return HEADER + '\n'.join(
+        (CONDITIONAL if conditional else SECTION).format(
+            manpages=mjoin(set(rulegroup.values())),
+            aliases=mjoin(k for k,v in rulegroup.items() if k != v),
+            rules='\n'.join('{}: {}'.format(k,v)
+                            for k,v in sorted(rulegroup.items())
+                            if k != v),
+            conditional=conditional)
+        for conditional,rulegroup in sorted(rules.items()))
+
+if __name__ == '__main__':
+    rules = create_rules(*sys.argv[1:])
+    print(make_makefile(rules), end='')