made compare_versions func into its own module. made tests

bin/pt-show-grants

@@ -16,6 +16,7 @@ BEGIN {
       OptionParser
       DSNParser
       Daemon
+      VersionCompare
    ));
 }
 
@@ -1727,6 +1728,52 @@ sub _d {
 # End Daemon package
 # ###########################################################################
 
+# ###########################################################################
+# VersionCompare package
+# This package is a copy without comments from the original.  The original
+# with comments and its test file can be found in the Bazaar repository at,
+#   lib/VersionCompare.pm
+#   t/lib/VersionCompare.t
+# See https://launchpad.net/percona-toolkit for more information.
+# ###########################################################################
+{
+package VersionCompare;
+
+use strict;
+use English qw(-no_match_vars);
+use constant PTDEBUG => $ENV{PTDEBUG} || 0;
+
+sub cmp {
+   my ($v1, $v2) = @_;
+
+   $v1 =~ s/[^\d\.]//;
+   $v2 =~ s/[^\d\.]//;
+
+   my @a = ( $v1 =~ /(\d+)\.?/g ); 
+   my @b = ( $v2 =~ /(\d+)\.?/g ); 
+   foreach my $n1 (@a) {
+      $n1 += 0;
+      if (!@b) {
+         return 1;
+      }  
+      my $n2 = shift @b;
+      $n2 += 0;
+      if ($n1 == $n2) {
+          next;
+      }
+      else {
+         return $n1 <=> $n2;
+      }  
+   }  
+   return @b ? -1 : 0;
+}
+
+
+1;
+}
+# ###########################################################################
+# End VersionCompare package
+# ###########################################################################
 
 # ###########################################################################
 # This is a combination of modules and programs in one -- a runnable module.
@@ -1858,9 +1905,9 @@ sub main {
          PTDEBUG && _d('Checking user', $user_host);
       }
 
-      # If MySQL 5.7+ then we need to use SHOW CREATE USER
+      # If MySQL 5.7.6+ then we need to use SHOW CREATE USER
       my @create_user;
-      if ( compare_versions($version, '5.7.6') >= 0 ) {
+      if ( VersionCompare::cmp($version, '5.7.6') >= 0 ) {
          eval {
             @create_user = @{ $dbh->selectcol_arrayref("SHOW CREATE USER $user_host") };
          };
@@ -2033,36 +2080,6 @@ sub split_grants {
    return @grants;
 }
 
-sub compare_versions {
-   my ($v1, $v2) = @_;
-
-   # Remove all but numbers and dots. 
-   # Assume simple 1.2.3 style
-   $v1 =~ s/[^\d\.]//;
-   $v2 =~ s/[^\d\.]//;
-
-   my @a = ( $v1 =~ /(\d+)\.?/g ); 
-   my @b = ( $v2 =~ /(\d+)\.?/g ); 
-   foreach my $n1 (@a) {
-      $n1 += 0; #convert to number
-      if (!@b) {
-         # b ran out of digits, a is larger
-         return 1;
-      }  
-      my $n2 = shift @b;
-      $n2 += 0; # convert to number
-      if ($n1 == $n2) {
-          # still tied?, fetch next 
-          next;
-      }
-      else {
-         # difference! return result
-         return $n1 <=> $n2;
-      }  
-   }  
-   # b still has digits? it's larger, else it's a tie
-   return @b ? -1 : 0;
-}
 
 sub _d {
    my ($package, undef, $line) = caller 0;