extfs: rpm: introduce the rpm2tags tool.

This is a preliminary step before being able to write tests for our rpm helper.

We introduce 'rpm2tags', a tool for converting RPM packages to parsable text
files. This will enable us to write tests that can run even where the 'rpm'
program isn't installed.

Signed-off-by: Mooffie <mooffie@gmail.com>

configure.ac

@@ -644,6 +644,7 @@ tests/src/vfs/Makefile
 tests/src/vfs/extfs/Makefile
 tests/src/vfs/extfs/helpers-list/Makefile
 tests/src/vfs/extfs/helpers-list/data/config.sh
+tests/src/vfs/extfs/helpers-list/misc/Makefile
 ])
 
 AC_OUTPUT

tests/src/vfs/extfs/helpers-list/Makefile.am

@@ -1,5 +1,7 @@
 PACKAGE_STRING = "/src/vfs/extfs/helpers-list"
 
+SUBDIRS = misc
+
 AM_CPPFLAGS = $(GLIB_CFLAGS) -I$(top_srcdir)
 
 # This lets mc_parse_ls_l.c override MC's message() without the linker

tests/src/vfs/extfs/helpers-list/misc/Makefile.am

@@ -0,0 +1,2 @@
+
+EXTRA_DIST = rpm2tags.pl

tests/src/vfs/extfs/helpers-list/misc/rpm2tags.pl

@@ -0,0 +1,103 @@
+use strict;
+use warnings;
+use Data::Dumper;
+
+my $help = <<EOF;
+WHAT
+----
+
+This script converts an RPM package into what we call a "tags file",
+which is simply an associative array listing all the tags and their
+values.
+
+WHY
+---
+
+For our rpm helper tests we need an RPM file. But we also want the tests
+to be able to run on systems where the rpm binary isn't installed. The
+solution: our tests work on "tags files" instead of real RPM files.
+
+HOW
+---
+
+Use it like this:
+
+    \$ perl $0 /path/to/some/package.rpm > test.input
+
+You can run this script only on systems where 'rpm' is installed.
+
+WHEW
+----
+
+After all was done the author of this script discovered something not
+mentioned in rpm's manpage: one can do "rpm -qp --xml pkg.rpm" to
+serialize the metadata and get the same effect. But this would just move
+the complexity to the test (in handling XML).
+EOF
+
+# Tag variations we're interested in and wish to record as well.
+my @formatted_tags = qw(
+  BUILDTIME:date
+  CHANGELOGTIME:date
+
+  REQUIREFLAGS:depflags
+  PROVIDEFLAGS:depflags
+  OBSOLETEFLAGS:depflags
+  CONFLICTFLAGS:depflags
+);
+
+# Big tags we want to omit to save space.
+my %skip = map {$_ => 1} qw(
+  HEADERIMMUTABLE
+);
+
+# Make 'rpm' print dates in the format our helper expects.
+$ENV{'LC_TIME'} = 'C';
+
+sub rpm2tags
+{
+  my ($rpm_pkg) = @_;
+
+  my %tags = ();
+
+  chomp(my @all_tags = `rpm --querytags`);
+  @all_tags = grep {!$skip{$_}} @all_tags;
+
+  foreach my $tag (@all_tags, @formatted_tags) {
+    $tags{$tag} = `rpm -qp --qf "%{$tag}" "$rpm_pkg"`;
+  }
+
+  # Add pseudo tags:
+  $tags{'_INFO'} = `rpm -qip "$rpm_pkg"`;
+
+  return %tags;
+}
+
+sub prolog
+{
+  my $cmdline = join(' ', 'perl', $0, @ARGV);
+  return <<EOF;
+# -*- mode: perl -*-
+# vim: filetype=perl
+#
+# This "tags file" was created by running the following command:
+#
+#    \$ $cmdline
+#
+# This file is used in our tests instead of the corresponding RPM file.
+# This lets us run the tests on systems where 'rpm' is not installed.
+EOF
+}
+
+sub main
+{
+  if (!$ARGV[0] || $ARGV[0] eq "--help" || $ARGV[0] eq "-h") {
+    print $help;
+    exit;
+  }
+  my %tags = rpm2tags($ARGV[0]);
+  $Data::Dumper::Terse = 1;
+  print(prolog(), "\n", '$tags = ', Dumper(\%tags), ";\n");
+}
+
+main();