use File::Path;
use File::Temp;
use File::stat;
+use MIME::Base64;
-# Copyright (C) 2010 Zygo Blaxell <dm5@mailtoo.hungrycats.org>
+# Copyright (C) 2010 Zygo Blaxell <dupemerge@mailtoo.hungrycats.org>
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
Usage: $0 link-dir
Hashes a NUL-separated list of files on stdin into link-dir.
-Version: 20100513.0
+Version: 0.20100519
USAGE
}
print STDERR "\bL";
link($from, $tmp_to) or die "link: $from -> $tmp_to: $!";
print STDERR "\bR";
- unless (rename($tmp_to, $to)) {
- my $saved_bang = $!;
- print STDERR "\bU";
- unlink($tmp_to) or warn "unlink: $tmp_to: $!"; # Try, possibly in vain, to clean up
- die "rename: $tmp_to -> $from: $saved_bang";
- }
- print STDERR "\b \b";
+ my $saved_bang;
+ $saved_bang = $! unless rename($tmp_to, $to);
+
+ # If $to exists and is a hardlink to $tmp_to (or $from),
+ # rename returns success but $tmp_to still exists.
+ print STDERR "\bU";
+ unlink($tmp_to) or warn "unlink: $tmp_to: $!" if -e $tmp_to;
+
+ die "rename: $tmp_to -> $from: $saved_bang" if $saved_bang;
+ print STDERR "\b";
}
my $link_dir = shift @ARGV;
-(-d $link_dir) or usage;
+usage unless $link_dir;
my $prefix_length = 3;
return ($prefix, $suffix);
}
+sub mkdir_p {
+ my ($dir) = @_;
+ return if -d $dir;
+ $dir =~ s:/+$::os;
+ my $parent;
+ ($parent = $dir) =~ s:[^/]+$::os;
+ if ($parent ne $dir) {
+ mkdir_p($parent);
+ print STDERR 'm';
+ mkdir($dir) or die "mkdir: $dir: $!";
+ }
+ die "mkdir: $dir: $!" unless -d $dir;
+}
+
sub prepare_parents {
my ($link_dir, $file) = @_;
my ($prefix, $suffix) = slash_prefix($file);
my $parent = "$link_dir/$prefix";
- print STDERR 'm';
- mkpath($parent, { verbose => 0 });
- print STDERR "\b";
- die "mkpath: $parent: $!" unless -d $parent;
+ mkdir_p($parent);
return "$parent/$suffix";
}
+sub name_ino {
+ my ($int64) = @_;
+ my $packed = pack('Q>', $int64);
+ $packed =~ s/^\0+//os;
+ my $base64_packed = encode_base64($packed, '');
+ $base64_packed =~ y:/:_:;
+ # Don't strip off the trailing padding since it makes the string
+ # so short we end up just putting it back on again.
+ # $base64_packed =~ s/=+$//os;
+ return $base64_packed;
+}
+
# ext3 cannot handle more than 32000 links to a file. Leave some headroom.
+# Arguably this should be configurable, but the losses are miniscule and
+# the coding for option support is not.
my $link_count_max = 31990;
$/ = "\0";
next if ($st->nlink > $link_count_max);
# Check link to inode
- my $inode_link = prepare_parents("$link_dir/inode", $st->ino);
+ my $inode_link = prepare_parents($link_dir, name_ino($st->ino));
print STDERR 'I';
my $inode_st = lstat($inode_link);
my $update_links;
# Compute digest
print STDERR 'd';
my $digest = digest($file);
- print STDERR "\b";
# Base64 uses /, we prefer _
$digest =~ y:/:_:;
# Check link to digest
- my $digest_link = prepare_parents("$link_dir/digest", $digest);
+ my $digest_link = prepare_parents($link_dir, $digest);
print STDERR 'D';
my $digest_st = lstat($digest_link);
if ($digest_st) {
undef $digest_st;
}
}
+ print STDERR "\b";
+
+ # Which file are we keeping?
+ my $keep_ino;
# If digest link exists, link it to file
if ($digest_st) {
# Old, replace input with old file
print STDERR '-';
link_files($digest_link, $file);
+ $keep_ino = $digest_st->ino;
} else {
# New, add input to digest
print STDERR '+';
link_files($file, $digest_link);
+ $keep_ino = $st->ino;
}
# A link to the inode indicates we are done, so do it last
- link_files($file, $inode_link);
+ $inode_link = prepare_parents($link_dir, name_ino($keep_ino));
+ print STDERR ' ';
+ link_files($digest_link, $inode_link);
}
};
warn "$file: $@" if $@;
}
+# Garbage collection
+print STDERR "\nGarbage collection in '$link_dir'...";
+chdir($link_dir) || die "chdir: $link_dir: $!";
+print STDERR "\nRemoving files with link count < 3 and temporary links...";
+system('find . -type f \( -links -3 -o -name ".*" \) -print0 | xargs -0rt rm -f') and die "system: exit status $?";
+print STDERR "\nRemoving empty directories...";
+system("find . -type d -empty -print0 | xargs -0rt rmdir -p --ignore-fail-on-non-empty") and die "system: exit status $?";
+print STDERR "\nDone.\n";
+
exit(0);
__END__