#!/usr/bin/perl

use Digest::SHA1 qw(sha1_hex sha1);

sub digest {
    my $line = shift;
    my $sha = new Digest::SHA1;
    open IN, "<", $line or die "\nfailed to open $_ for reading\n";
    binmode IN;
    $sha->addfile(*IN);
    my $hex = $sha->hexdigest;
    close IN;
    return $hex;    
}

while (<STDIN>) {
    chomp;
    $line = $_;
    @a = stat($line);
    if (-f $line) {
	$hex = digest($line);
    } else {
	$hex = '-';
    }

    print "@a $hex $line\n";
}

##</code><code>##

#!/usr/bin/perl

# Snapshot a list of files. We must be passed a location for the snapshots. The catalog data are read from STDIN and written to the CATALOG file in the snapshot

sub makeDir {
    my $path = shift;
    my $u = umask(0);
    my $ret = mkdir $path;
    umask($u);
    return $ret;
}

# This function returns the path to the files content hash (ie the
# file in 'hashes' containing the same data) given the hash. Path is
# relative to 'hashes'. We may want to subdivide these you see, so we
# don't end up with a bazillion files in that directory.
sub pathToHash {
    my $h = shift;
    my $path = shift;
    $h=~/(..)(..)(.*)/;
    makeDir("$path/$1") or die "Couldn't write to hashes dir $path/$1!" unless -d "$path/$1";
    makeDir("$path/$1/$2") or die "Couldn't write to hashes dir $path/$1!" unless -d "$path/$1/$2";
    return "$path/$1/$2/$3";
}

$snaps = $ARGV[0];

print STDERR "Snapshoting to $snaps...\n";

# make the snapshot dir
die "Can't find snapshot dir $snaps" unless -d $snaps;

($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) = localtime;

$year+=1900;
$mon++;

makeDir "$snaps/$year";
makeDir "$snaps/$year/$mon";
makeDir "$snaps/$year/$mon/$mday-$hour-$min-$sec";

$snappath = "$snaps/$year/$mon/$mday-$hour-$min-$sec";

die "Can't find hashes dir" unless -d "$snaps/hashes";

# The catalog is important as it records correct permissions and owners. These are not necessarily correct in the files since they are linked to the hashes
open OUT, ">$snappath/CATALOG" or die "failed to open $snappath/CATALOG";

while (<STDIN>) {
    # dump the catalog entry to the catalog.
    print OUT $_;

    # Parse the catalog entry
    @a = /(\d+) (\d+) (\d+) (\d+) (\d+) (\d+) (\d+) (\d+) (\d+) (\d+) (\d+) (\d+) (\d+) ([\da-z]+|-) (.*)/;

    print "Snap: $a[14]\n";

    $name = $a[14];
    # Trim leading dot
    $name=~s/^\.//;

    # now, what we do depends on the file type...
    if (-d $a[14]) {
	# make dir in the snapshot directory
	makeDir "$snappath/$name";
    }
    elsif (-f $a[14]) {
	# See if its hash file exists
	$pth = pathToHash($a[13], "$snaps/hashes");
	system "cp", $a[14], $pth unless -f $pth;
	# system "ln", $pth, "$snappath/$name";
        link $pth, "$snappath/$name";
    }
    else {
	# Just copy it across using the cp command (it must be a device or some other special file)
	system "cp", $a[14], "$snappath/$name";
    }
}

close OUT;

# After generating the snapshot we should mark everything read only.
system "chmod", "-R", "-w", "$snappath";

# If we are passed a second argument it's a label and we do this...
if ($ARGV[1]) {
    $label = "$snaps/$ARGV[1]--$year--$mon--$mday--$hour-$min-$sec";

    symlink $snappath, $label;
}

##</code><code>##


# Shell script

# Snapshot current directory. 

# This takes 1 or 2 args. The first one is the path to the snapshots DIR. 
# The 2nd (optional) is a label for the snapshot if desired, which will 
# create a symbolic link at the root of the snapshots DIR

# a simple pipeline. Find is used to generate a filename list
find . | catalog | snap $1 $2