#!/usr/bin/perl

#

# Find scene dependencies in this directory

#

# This a re-write of Greg's raddepend.csh.

# Scene dependencies are now parsed recursively with the fs tree.

#

# This (like the old CSH script) relies on the file's atime and

# will not work if the partition is mounted with the noatime option,

# or if the file system does not store the files' access time.

#

# not-a-bug: https://bugs.launchpad.net/ubuntu/+bug/490500

# LINUX file systems are now defaulting to relative atime (relatime) which

# updates the atime only if the previous atime update is older than

# the mtime or ctime update.

# This effectively renders this script (as well as the old raddepend.csh)

# useless on a LINUX system, unless the fs is mounted with strictatime:

# $ sudo mount -o remount,strictatime /home

#

# Axel, Oct 2010

use strict;

use warnings;

use File::Find qw/ find /;

use File::Basename;

# Use path from the first scene file.

#TODO: Use all args, not just first one.

die("$0: Need at least one scene file.\n") unless ($#ARGV >= 0);

my (undef, $dir, undef) = fileparse($ARGV[0]);

#TODO: Make this a new -t option

#system("touch -m `find . -type f`");

#sleep (2);

# Get atimes of all files in this dir and all subdirs.

system("sync");

my %atimes0;   # atimes before genbbox command

my %atimes1;   # atimes after genbbox command

find(sub {$atimes0{$File::Find::name} = (stat())[8] if -f;}, $dir);

my $cmd = 'getbbox -w ' . join(' ', @ARGV) . ' >/dev/null';

my $exstat = system("$cmd");

# Use exit status of genbbox command

exit $exstat unless ($exstat == 0);

system("sync");

sleep(1);   # atime resolution is 1 second.

# Compare the atimes before and after genbbox was run

find(sub {$atimes1{$File::Find::name} = (stat())[8] if -f;}, $dir);

my @touched = ();

while(my ($key, $value) = each(%atimes0)) {

	push(@touched, $key) if ($value < $atimes1{$key});

}

# @touched should contain at least the file(s) we were called with.

# Exit with error if @touched is empty.

die("$0: Could not determine scene dependencies.\n") unless ($#touched > 0);

#TODO: Print hint with strictatime mount option

foreach my $file (@touched) {

	# Remove all ARGV files from @touched list to ensure output is

	# identical to that of the old raddepend.csh script

	print "$file\n" unless grep($_ eq $file, @ARGV);

}

#EOF