src: rewrite symfile sorting checker in Python

As part of a goal to eliminate Perl from libvirt build tools,
rewrite the check-symsorting.pl tool in Python.

This was a straight conversion, manually going line-by-line to
change the syntax from Perl to Python. Thus the overall structure
of the file and approach is the same.

Tested-by: Cole Robinson <crobinso@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

scripts/check-symsorting.py

@@ -0,0 +1,117 @@
+#!/usr/bin/env python
+
+# Copyright (C) 2012-2019 Red Hat, Inc.
+#
+# This library 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.
+#
+# This library 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 this library.  If not, see
+# <http://www.gnu.org/licenses/>.
+
+from __future__ import print_function
+
+import os.path
+import re
+import sys
+
+if len(sys.argv) < 3:
+    print("syntax: %s SRCDIR SYMFILE..." % sys.argv[0], file=sys.stderr)
+    sys.exit(1)
+
+
+def check_sorting(group, symfile, line, groupfile, lastgroup):
+    sortedgroup = sorted(group, key=str.lower)
+    issorted = True
+    first = None
+    last = None
+
+    err = False
+    # Check that groups are in order and groupfile exists
+    if lastgroup is not None and lastgroup.lower() > groupfile.lower():
+        print("Symbol block at %s:%s: block not sorted" %
+              (symfile, line), file=sys.stderr)
+        print("Move %s block before %s block" %
+              (groupfile, lastgroup), file=sys.stderr)
+        print("", file=sys.stderr)
+        err = True
+
+    if not os.path.exists(os.path.join(srcdir, groupfile)):
+        print("Symbol block at %s:%s: %s not found" %
+              (symfile, line, groupfile), file=sys.stderr)
+        print("", file=sys.stderr)
+        err = True
+
+    # Check that symbols within a group are in order
+    for i in range(len(group)):
+        if sortedgroup[i] != group[i]:
+            if first is None:
+                first = i
+
+            last = i
+            issorted = False
+
+    if not issorted:
+        actual = group[first:(last - first + 1)]
+        expect = sortedgroup[first:(last - first + 1)]
+        print("Symbol block at %s:%s: symbols not sorted" %
+              (symfile, line), file=sys.stderr)
+        for g in actual:
+            print("  %s" % g, file=sys.stderr)
+        print("Correct ordering", file=sys.stderr)
+        for g in expect:
+            print("  %s" % g, file=sys.stderr)
+        print("", file=sys.stderr)
+        err = True
+
+    return err
+
+
+ret = 0
+srcdir = sys.argv[1]
+lastgroup = None
+for symfile in sys.argv[2:]:
+    with open(symfile, "r") as fh:
+        lineno = 0
+        groupfile = ""
+        group = []
+        thisline = 0
+
+        for line in fh:
+            thisline = thisline + 1
+            line = line.strip()
+
+            filenamematch = re.search(r'''^#\s*((\w+\/)*(\w+\.h))\s*$''', line)
+            if filenamematch is not None:
+                groupfile = filenamematch.group(1)
+            elif line == "":
+                if len(group) > 0:
+                    if check_sorting(group, symfile, lineno,
+                                     groupfile, lastgroup):
+                        ret = 1
+
+                group = []
+                lineno = thisline
+                lastgroup = groupfile
+            elif line[0] == '#':
+                # Ignore comments
+                pass
+            else:
+                line = line.strip(";")
+                group.append(line)
+
+        if len(group) > 0:
+            if check_sorting(group, symfile, lineno,
+                             groupfile, lastgroup):
+                ret = 1
+
+        lastgroup = None
+
+sys.exit(ret)