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package App::Hashl;
use strict;
use warnings;
use 5.010;
use Digest::SHA qw(sha1_hex);
use Storable qw(nstore retrieve);
my $VERSION = '0.1';
=head1 NAME
App::Hashl - Partially hash files, check if files are equal etc.
=head1 SYNOPSIS
use App::Hashl;
my $hashl = App::Hashl->new();
# or: App::Hashl->new_from_file($database_file);
=head1 VERSION
This manual documents App::Hashl version 0.2
=head1 DESCRIPTION
App::Hashl contains utilities to hash the first n bytes of a file, store and
recall this, check if another file is already in the database and optionally
ignore file hashes.
=head1 METHODS
=over
=item $hashl = App::Hashl->new(I<%conf>)
Returns a new B<App::Hashl> object. Accepted parameters are:
=over
=item B<read_size> => I<bytes>
How many bytes of a file to consider for the hash. Defaults to 4 MiB (4 *
2**20 bytes).
=back
=cut
sub new {
my ($obj, %conf) = @_;
my $ref = {
files => {},
ignored => {},
};
$ref->{config} = \%conf;
$ref->{config}->{read_size} //= (2 ** 20) * 4, # 4 MiB
return bless($ref, $obj);
}
=item $hashl = App::Hashl->new_from_file(I<$file>)
Returns the B<App::Hashl> object saved to I<file> by a prior $hashl->save
call.
=cut
sub new_from_file {
my ($obj, $file) = @_;
my $ref = retrieve($file);
return bless($ref, $obj);
}
=item $hashl->si_size(I<$bytes>)
Returns I<bytes> as a human-readable SI-size, such as "1.0k", "50.7M", "2.1G".
The returned string is always six characters long.
=cut
sub si_size {
my ($self, $bytes) = @_;
my @post = (' ', qw(k M G T));
while ($bytes >= 1024) {
$bytes /= 1024;
shift @post;
}
return sprintf("%6.1f%s", $bytes, $post[0]);
}
=item $hashl->hash_file(I<$file>)
Returns the SHA1 hash of the first n bytes (as configured via B<read_size>) of
I<file>
=cut
sub hash_file {
my ($self, $file) = @_;
my ($fh, $data);
open($fh, '<', $file)
or die("Can't open ${file} for reading: $!\n");;
binmode($fh)
or die("Can't set binmode on ${file}: $!\n");
read($fh, $data, $self->{config}->{read_size})
or die("Can't read ${file}: $!\n");
close($fh)
or die("Can't close ${file}: $!\n");
return sha1_hex($data);
}
=item $hashl->hash_in_db(I<$hash>)
Checks if I<hash> is in the database. If it is, returns the filename it is
associated with. If it is ignored, returns "// ignored" (subject to change).
Otherwise, returns undef.
=cut
sub hash_in_db {
my ($self, $hash) = @_;
if ($self->{ignored}->{$hash}) {
return '// ignored';
}
for my $name ($self->files()) {
my $file = $self->file($name);
if ($file->{hash} eq $hash) {
return $name;
}
}
return undef;
}
=item $hashl->file_in_db(I<$file>)
Checks if I<file>'s hash is in the database. For the return value, see
B<hash_in_db>.
=cut
sub file_in_db {
my ($self, $file) = @_;
return $self->hash_in_db($self->hash_file($file));
}
=item $hashl->read_size()
Returns the current read size. Note that once an B<App::Hashl> object has
been created, it is not possible to change the read size.
=cut
sub read_size {
my ($self) = @_;
return $self->{config}->{read_size};
}
=item $hashl->file(I<$name>)
Returns a hashref describing the file. The layout is as follows:
hash => file's hash,
mtime => mtime as UNIX timestamp,
size => file size in bytes,
=cut
sub file {
my ($self, $name) = @_;
return $self->{files}->{$name};
}
=item $hashl->delete_file(I<$name>)
Remove the file from the database
=cut
sub delete_file {
my ($self, $name) = @_;
delete $self->{files}->{$name};
}
=item $hashl->files()
Returns a list of all file names in the database
=cut
sub files {
my ($self) = @_;
return keys %{ $self->{files} };
}
=item $hashl->add_file(I<%data>)
Add a file to the database. Required keys in I<%data> are:
=over
=item B<file> => I<name>
relateve file name to store in the database
=item B<path> => I<path>
Full path to the file
=back
If the file already is in the database, it is only updated if both the file
size and the mtime have changed.
=cut
sub add_file {
my ($self, %data) = @_;
my $file = $data{file};
my $path = $data{path};
my ($size, $mtime) = (stat($path))[7,9];
if ($self->file($file) and
$self->file($file)->{mtime} == $mtime and
$self->file($file)->{size} == $size ) {
return;
}
my $hash = $self->hash_file($path);
if ($self->{ignored}->{$hash}) {
return;
}
$self->{files}->{$file} = {
hash => $hash,
mtime => $mtime,
size => $size,
};
}
=item $hashl->ignored()
Returns a list of all ignored file hashes
=cut
sub ignored {
my ($self) = @_;
if (exists $self->{ignored}) {
return keys %{ $self->{ignored} };
}
else {
return ();
}
}
=item $hashl->ignore(I<$file>, I<$path>)
Removes I<$file> from the database and adds I<$path> to the list of ignored
file hashes.
=cut
sub ignore {
my ($self, $file, $path) = @_;
$self->delete_file($file);
$self->{ignored}->{ $self->hash_file($path) } = 1;
}
=item $hashl->save(I<$file>)
Save the B<App::Hashl> object with all data to I<$file>. It can later be
retrieved via B<new_from_file>.
=cut
sub save {
my ($self, $file) = @_;
nstore($self, $file);
}
1;
__END__
=back
=head1 DEPENDENCIES
B<Digest::SHA>.
=head1 AUTHOR
Copyright (C) 2011 by Daniel Friesel E<lt>derf@finalrewind.orgE<gt>
=head1 LICENSE
0. You just DO WHAT THE FUCK YOU WANT TO.
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