modules/Version.pm

   1 package Version;
   2
   3 # ************************************************************
   4 # Description   : Central location for the MPC version.
   5 # Author        : Chad Elliott
   6 # Create Date   : 1/5/2003
   7 # ************************************************************
   8
   9 # ************************************************************
  10 # Pragmas
  11 # ************************************************************
  12
  13 use strict;
  14 use File::Spec;
  15
  16 # ************************************************************
  17 # Data Section
  18 # ************************************************************
  19
  20 ## This is the starting major and minor version
  21 my $version = '5.1';
  22 my $once    = 1;
  23 my $cache   = 'modules/.version';
  24
  25 # ************************************************************
  26 # Subroutine Section
  27 # ************************************************************
  28
  29 sub get {
  30   if ($once) {
  31     ## We only need to do this once
  32     $once = 0;
  33
  34     ## Attempt to dynamically determine the revision part of the version
  35     ## string every time the version number is requested.  This only happens
  36     ## if the --version option is used, an invalid option is used, and when
  37     ## the process starts up and the version hasn't been cached yet.
  38     my $rev = '?';
  39     my $cwd = Cwd::getcwd();
  40     if (chdir(::getBasePath())) {
  41       ## Get the git revision for the final part of the version string.
  42       my $nul = File::Spec->devnull();
  43       my $r = _readVersion("git rev-parse --short HEAD 2> $nul |");
  44       if (defined $r) {
  45         ## Store the version for later use, in the event that the git
  46         ## revision isn't available in the future.
  47         if (open(CLH, ">$cache")) {
  48           print CLH "$r\n";
  49           close(CLH);
  50         }
  51       }
  52       else {
  53         ## See if we can load in the previously stored version string.
  54         $r = _readVersion($cache);
  55       }
  56
  57       ## Set the revision string if we were able to read one.
  58       $rev = $r if (defined $r);
  59
  60       chdir($cwd);
  61     }
  62
  63     ## We then append the revision to the version string.
  64     $version .= ".$rev";
  65   }
  66
  67   return $version;
  68 }
  69
  70 sub cache {
  71   ## Attempt to cache the revision if the cache file does not exist.
  72   ## This will allow the revision to be obtained in the event that git
  73   ## cannot return the revision information at a later time.
  74   get() if (!-e ::getBasePath() . '/' . $cache);
  75 }
  76
  77 1;
  78
  79 sub _readVersion {
  80   my $file = shift;
  81   my $rev;
  82   if (open(CLH, $file)) {
  83     while(<CLH>) {
  84       if (/^(\w+)$/) {
  85         $rev = $1;
  86         last;
  87       }
  88     }
  89     close(CLH);
  90   }
  91   return $rev;
  92 }
  93