tests: rewrite qemu capability grouper in Python

As part of a goal to eliminate Perl from libvirt build tools,
rewrite the group-qemu-caps.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: Cole Robinson <crobinso@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

Makefile.am

@@ -59,6 +59,7 @@ EXTRA_DIST = \
   scripts/esx_vi_generator.py \
   scripts/genpolkit.py \
   scripts/gensystemtap.py \
+  scripts/group-qemu-caps.py \
   scripts/header-ifdef.py \
   scripts/hyperv_wmi_generator.py \
   scripts/minimize-po.py \

build-aux/syntax-check.mk

@@ -2187,7 +2187,8 @@ test-wrap-argv:
 	$(PYTHON) $(top_srcdir)/scripts/test-wrap-argv.py --check
 
 group-qemu-caps:
-	$(AM_V_GEN)$(PERL) $(top_srcdir)/tests/group-qemu-caps.pl --check $(top_srcdir)/
+	$(AM_V_GEN)$(RUNUTF8) $(PYTHON) $(top_srcdir)/scripts/group-qemu-caps.py \
+		--check --prefix $(top_srcdir)/
 
 # List all syntax-check exemptions:
 exclude_file_name_regexp--sc_avoid_strcase = ^tools/vsh\.h$$

scripts/group-qemu-caps.py

@@ -0,0 +1,121 @@
+#!/usr/bin/env python3
+#
+# 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/>.
+#
+#
+# Regroup array values into smaller groups separated by numbered comments.
+#
+# If --check is the first parameter, the script will return
+# a non-zero value if a file is not grouped correctly.
+# Otherwise the files are regrouped in place.
+
+import argparse
+import re
+import subprocess
+import sys
+
+
+def regroup_caps(check, filename, start_regex, end_regex,
+                 trailing_newline, counter_prefix):
+    step = 5
+
+    original = []
+    with open(filename, "r") as fh:
+        for line in fh:
+            original.append(line)
+
+    fixed = []
+    game_on = False
+    counter = 0
+    for line in original:
+        line = line.rstrip("\n")
+        if game_on:
+            if re.search(r'''.*/\* [0-9]+ \*/.*''', line):
+                continue
+            if re.search(r'''^\s*$''', line):
+                continue
+            if counter % step == 0:
+                if counter != 0:
+                    fixed.append("\n")
+                fixed.append("%s/* %d */\n" % (counter_prefix, counter))
+
+            if not (line.find("/*") != -1 and line.find("*/") == -1):
+                # count two-line comments as one line
+                counter = counter + 1
+
+        if re.search(start_regex, line):
+            game_on = True
+        elif game_on and re.search(end_regex, line):
+            if (counter - 1) % step == 0:
+                fixed = fixed[:-1]  # /* $counter */
+                if counter != 1:
+                    fixed = fixed[:-1]  # \n
+
+            if trailing_newline:
+                fixed.append("\n")
+
+            game_on = False
+
+        fixed.append(line + "\n")
+
+    if check:
+        orig = "".join(original)
+        new = "".join(fixed)
+        if new != orig:
+            diff = subprocess.Popen(["diff", "-u", filename, "-"],
+                                    stdin=subprocess.PIPE)
+            diff.communicate(input=new.encode('utf-8'))
+
+            print("Incorrect line wrapping in $file",
+                  file=sys.stderr)
+            print("Use group-qemu-caps.py to generate data files",
+                  file=sys.stderr)
+            return False
+    else:
+        with open(filename, "w") as fh:
+            for line in fixed:
+                print(line, file=fh, end='')
+
+    return True
+
+
+parser = argparse.ArgumentParser(description='QEMU capabilities group formatter')
+parser.add_argument('--check', action="store_true",
+                    help='check existing files only')
+parser.add_argument('--prefix', default='',
+                    help='source code tree prefix')
+args = parser.parse_args()
+
+errs = False
+
+if not regroup_caps(args.check,
+                    args.prefix + 'src/qemu/qemu_capabilities.c',
+                    r'virQEMUCaps grouping marker',
+                    r'\);',
+                    0,
+                    "              "):
+    errs = True
+
+if not regroup_caps(args.check,
+                    args.prefix + 'src/qemu/qemu_capabilities.h',
+                    r'virQEMUCapsFlags grouping marker',
+                    r'QEMU_CAPS_LAST \/\* this must',
+                    1,
+                    "    "):
+    errs = True
+
+if errs:
+    sys.exit(1)
+sys.exit(0)

tests/group-qemu-caps.pl

@@ -1,124 +0,0 @@
-#!/usr/bin/env perl
-#
-# 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/>.
-#
-#
-# Regroup array values into smaller groups separated by numbered comments.
-#
-# If --check is the first parameter, the script will return
-# a non-zero value if a file is not grouped correctly.
-# Otherwise the files are regrouped in place.
-
-use strict;
-use warnings;
-
-my $check = 0;
-
-if (defined $ARGV[0] && $ARGV[0] eq "--check") {
-    $check = 1;
-    shift @ARGV;
-}
-
-my $prefix = '';
-if (defined $ARGV[0]) {
-    $prefix = $ARGV[0];
-    shift @ARGV;
-}
-
-my $ret = 0;
-if (&regroup_caps($prefix . 'src/qemu/qemu_capabilities.c',
-                  'virQEMUCaps grouping marker',
-                  '\);',
-                  0,
-                  "              ") < 0) {
-    $ret = 1;
-}
-if (&regroup_caps($prefix . 'src/qemu/qemu_capabilities.h',
-                  'virQEMUCapsFlags grouping marker',
-                  'QEMU_CAPS_LAST \/\* this must',
-                  1,
-                  "    ") < 0) {
-    $ret = 1;
-}
-
-exit $ret;
-
-sub regroup_caps {
-    my $filename = shift;
-    my $start_regex = shift;
-    my $end_regex = shift;
-    my $trailing_newline = shift;
-    my $counter_prefix = shift;
-    my $step = 5;
-
-    open FILE, '<', $filename or die "cannot open $filename: $!";
-    my @original = <FILE>;
-    close FILE;
-
-    my @fixed;
-    my $game_on = 0;
-    my $counter = 0;
-    foreach (@original) {
-        if ($game_on) {
-            next if ($_ =~ '/\* [0-9]+ \*/');
-            next if (/^\s+$/);
-            if ($counter % $step == 0) {
-                if ($counter != 0) {
-                    push @fixed, "\n";
-                }
-                push @fixed, "$counter_prefix/* $counter */\n";
-            }
-            if (!($_ =~ '/\*' && !($_ =~ '\*/'))) {
-                # count two-line comments as one line
-                $counter++;
-            }
-        }
-        if (/$start_regex/) {
-            $game_on = 1;
-        } elsif ($game_on && $_ =~ /$end_regex/) {
-            if (($counter -1) % $step == 0) {
-                pop @fixed; # /* $counter */
-                if ($counter != 1) {
-                    pop @fixed; # \n
-                }
-            }
-            if ($trailing_newline) {
-                push @fixed, "\n";
-            }
-            $game_on = 0;
-        }
-        push @fixed, $_;
-    }
-
-    if ($check) {
-        my $nl = join('', @fixed);
-        my $ol = join('', @original);
-        unless ($nl eq $ol) {
-            open DIFF, "| diff -u $filename -" or die "cannot run diff: $!";
-            print DIFF $nl;
-            close DIFF;
-
-            print STDERR "Incorrect array grouping in $filename\n";
-            print STDERR "Use group-qemu-caps.pl to group long array members\n";
-            return -1;
-        }
-    } else {
-        open FILE, '>', $filename or die "cannot open $filename: $!";
-        foreach my $line (@fixed) {
-            print FILE $line;
-        }
-        close FILE;
-    }
-}