package Hash::Dirty;
use warnings;
use strict;
=head1 NAME
Hash::Dirty - Keep track of whether a hash is dirty or not
=head1 VERSION
Version 0.023
=cut
our $VERSION = '0.023';
=head1 SYNOPSIS
use Hash::Dirty;
my %hash;
tie %hash, qw/Hash::Dirty/, { a => 1 };
(tied %hash)->is_dirty; # Nope, not dirty yet.
$hash{a} = 1;
(tied %hash)->is_dirty; # Still not dirty yet.
$hash{b} = 2;
(tied %hash)->is_dirty; # Yes, now it's dirty
(tied %hash)->dirty_keys; # ( b )
$hash{a} = "hello";
(tied %hash)->dirty_keys; # ( a, b )
(tied %hash)->dirty_values; # ( "hello", 2 )
(tied %hash)->dirty } # { a => 1, b => 1 }
(tied %hash)->reset;
(tied %hash)->is_dirty; # Nope, not dirty anymore.
$hash{c} = 3;
(tied %hash)->is_dirty; # Yes, dirty again.
# %hash is { a => "hello", b => 2, c => 3 }
(tied %hash)->dirty_slice } # { c => 3 }
# Alternately:
use Hash::Dirty;
my $hash = Hash::Dirty::hash;
# Also:
my ($object, $hash) = Hash::Dirty->new;
$hash->{a} = 1; # Etc., etc.
$object->is_dirty;
=head1 DESCRIPTION
Hash::Dirty will keep track of the dirty keys in a hash, letting you which values changed.
Currently, Hash::Dirty will only inspect a hash shallowly, that is, it does not deeply compare
the contents of supplied values (say a HASH reference, ARRAY reference, or some other opaque object).
This module was inspired by DBIx::Class::Row
Currently, setting, deleting keys or clearing the hash means that the object will lose history, so it will know
that something has changed, but not if it is reset back at some later date:
my ($object, $hash) = Hash::Dirty->new({ a => 1 });
$object->is_dirty; # Nope
$hash->{a} = 2;
$object->is_dirty; # Yup
$hash->{a} = 1;
$object->is_dirty; # Yup, still dirty, even though the original value was 1
=cut
use Scalar::Util qw/weaken/;
use Sub::Exporter -setup => {
exports => [
hash => sub { return sub {
my ($object, $hash) = __PACKAGE__->new(@_);
return $hash;
} },
],
};
use Tie::Hash;
use base qw/Tie::ExtraHash/;
=head1 EXPORTS
=head2 hash( <hash> )
Creates a new Hash::Dirty object and returns the tied hash reference, per Hash::Dirty->new.
If supplied, will use <hash> as the storage (initializing the object accordingly)
=cut
use constant STORAGE => 0;
use constant DIRTY => 1;
use constant HASH => 2;
sub TIEHASH {
my ($class, $storage) = @_;
$storage ||= {};
my $self = [];
$self->[STORAGE()] = $storage;
$self->[DIRTY()] = {};
return bless $self, $class;
}
=head1 METHODS
=cut
=head2 Hash::Dirty->new( <hash> )
Creates and returns a new Hash::Dirty object
If supplied, will use <hash> as the storage (initializing the object accordingly)
In list context, new will return both the object and the "regular" hash:
my ($object, $hash) = Hash::Dirty->new;
$hash->{a} = 1;
$object->is_dirty; # Yup, it's dirty
=cut
sub new {
my $class = shift;
my %hash;
my $self = tie %hash, $class, @_;
my $hash = \%hash;
$self->[HASH()] = $hash;
weaken $self->[HASH()];
return wantarray ? ($self, \%hash) : $self;
}
=head2 $object->hash
Returns a reference to the overlying hash
=cut
sub hash {
my $self = shift;
return $self->[HASH()];
}
=head2 $object->is_dirty
Returns 1 if the hash is dirty at all, 0 otherwise
=head2 $object->is_dirty ( <key> )
Returns 1 if <key> is dirty, 0 otherwise
=head2 $object->is_dirty ( $key, $key, ..., )
Returns 1 if any <key> is dirty, 0 otherwise
=cut
sub is_dirty {
my $self = shift;
if (@_) {
for my $key (@_) {
return 1 if exists $self->[DIRTY()]->{$key};
}
}
else {
return 1 if $self->dirty_keys;
}
return 0;
}
=head2 $object->reset
Resets the hash to non-dirty status
This method affects the dirtiness only, it does not erase or alter the hash in anyway
=cut
sub reset {
my $self = shift;
$self->[DIRTY()] = {};
}
=head2 $object->dirty
Returns a hash indicating which keys are dirty
In scalar context, returns a hash reference
=cut
sub dirty {
my $self = shift;
my %dirty = %{ $self->[DIRTY()] };
return wantarray ? %dirty : \%dirty;
}
sub _storage {
my $self = shift;
my %storage = %{ $self->[STORAGE()] };
return wantarray ? %storage : \%storage;
}
=head2 $object->dirty_slice
Returns a hash slice containg only the dirty keys and values
In scalar context, returns a hash reference
=cut
sub dirty_slice {
my $self = shift;
my %slice = map { $_ => $self->[STORAGE()]{$_} } $self->dirty_keys;
return wantarray? %slice : \%slice;
}
=head2 $object->dirty_keys
Returns a list of dirty keys
=cut
sub dirty_keys {
my $self = shift;
return keys %{ $self->[DIRTY()] };
}
=head2 $object->dirty_values
Returns a list of dirty values
=cut
sub dirty_values {
my $self = shift;
return map { $self->[STORAGE()]{$_} } $self->dirty_keys;
}
sub STORE {
my ($self, $key, $value) = @_;
my $storage = $self->[STORAGE()];
my $new = $value;
my $old = $storage->{$key};
$storage->{$key} = $new;
# Taken from DBIx::Class::Row::set_column
$self->[DIRTY()]{$key} = 1 if (defined $old ^ defined $new) || (defined $old && $old ne $new);
return $new;
}
=head2 $object->set( <key>, <value> )
=head2 $object->store( <key>, <value> )
=cut
*set = \&STORE;
*store = \&STORE;
=head2 $object->get( <key> )
=head2 $object->fetch( <key> )
=cut
*get = \&Tie::ExtraHash::FETCH;
*fetch = \&Tie::ExtraHash::FETCH;
sub CLEAR {
my $self = shift;
my $storage = $self->[STORAGE()];
$self->[DIRTY()]{$_} = 1 for keys %$storage;
%$storage = ();
}
=head2 $object->clear
=cut
*clear = \&Tie::ExtraHash::CLEAR;
sub DELETE {
my ($self, $key) = @_;
my $storage = $self->[STORAGE()];
$self->[DIRTY()]{$key} = 1 if exists $storage->{$key};
return delete $storage->{$key};
}
=head2 $object->delete( <key> )
=cut
*delete = \&Tie::ExtraHash::DELETE;
=head1 AUTHOR
Robert Krimen, C<< <rkrimen at cpan.org> >>
=head1 BUGS
Please report any bugs or feature requests to
C<bug-hash-dirty at rt.cpan.org>, or through the web interface at
L<http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Hash-Dirty>.
I will be notified, and then you'll automatically be notified of progress on
your bug as I make changes.
=head1 SUPPORT
You can find documentation for this module with the perldoc command.
perldoc Hash::Dirty
You can also look for information at:
=over 4
=item * AnnoCPAN: Annotated CPAN documentation
L<http://annocpan.org/dist/Hash-Dirty>
=item * CPAN Ratings
L<http://cpanratings.perl.org/d/Hash-Dirty>
=item * RT: CPAN's request tracker
L<http://rt.cpan.org/NoAuth/Bugs.html?Dist=Hash-Dirty>
=item * Search CPAN
L<http://search.cpan.org/dist/Hash-Dirty>
=back
=head1 ACKNOWLEDGEMENTS
=head1 COPYRIGHT & LICENSE
Copyright 2007 Robert Krimen, all rights reserved.
This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
=cut
1; # End of Hash::Dirty