cache-apply

#!/usr/bin/perl -w

# Sat Jun 15 17:01:12 BST 2013
(my $email='XXX%YYY,ch')=~ tr/%,/@./;

use strict;

$0=~ /(.*?)([^\/]+)\z/s or die "?";
my ($mydir, $myname)=($1,$2);
sub usage {
    print STDERR map{"$_\n"} @_ if @_;
    print "$myname cmd sourcefile(s) targetfile

  Runs cmd sourcefile(s) targetfile unless targetfile exists and is
  newer than the sourcefile(s).

  Kind of a 'mini-make', but doesn't need config files.

  (Christian Jaeger <$email>)
";
exit (@_ ? 1 : 0);
}

use Getopt::Long;
our $verbose=0;
#our $opt_dry;
GetOptions("verbose"=> \$verbose,
	   "help"=> sub{usage},
	   #"dry-run"=> \$opt_dry,
	   ) or exit 1;
usage unless @ARGV>=2;

our $cmd=shift;
our $target= pop @ARGV;
our @sources= @ARGV;

use Chj::xperlfunc qw(Xstat xstat xexec);

sub build {
    xexec $cmd, @sources, $target
}

if (my $t= Xstat $target) {
    for my $source (@sources) {
	my $s= xstat $source;
	if ($t->mtime <= $s->mtime) {
	    build;
	}
    }
} else {
    build;
}


#use Chj::ruse;
#use Chj::Backtrace; use Chj::repl; repl;