package Zing::Lookup;
use 5.014;
use strict;
use warnings;
use registry 'Zing::Types';
use routines;
use Data::Object::Class;
use Data::Object::ClassHas;
extends 'Zing::Domain';
our $VERSION = '0.27'; # VERSION
# BUILDERS
fun BUILD($self) {
my $savepoint = $self->savepoint;
if ($savepoint->test) {
$self->{state} = $savepoint->snapshot;
$self->{position} = $savepoint->position;
$self->{metadata} = $savepoint->metadata;
}
return $self->apply;
}
# METHODS
method cursor() {
return $self->app->cursor(lookup => $self);
}
method decr(Any @args) {
$self->throw(error_not_supported($self, 'decr'));
}
around del($key) {
my $name = $self->hash($key);
my $item = $self->state->{$name};
return $self if !$item;
my $next = $item->{next};
my $prev = $item->{prev};
if ($next && $prev) {
$self->change('set', $prev, {%{$self->state->{$prev}}, next => $next});
$self->change('set', $next, {%{$self->state->{$next}}, prev => $prev});
}
elsif ($next && !$prev) {
$self->metadata->{tail} = $next;
$self->change('set', $next, {%{$self->state->{$next}}, prev => undef});
}
elsif (!$next && $prev) {
$self->metadata->{head} = $prev;
$self->change('set', $prev, {%{$self->state->{$prev}}, next => undef});
}
$self->$orig($name);
$self->app->domain(name => $item->{name})->drop;
return $self;
}
around drop() {
if (my $savepoint = $self->savepoint) {
$savepoint->drop if $savepoint->test;
}
return $self->$orig;
}
method get(Str $key) {
my $data = $self->apply->state->{$self->hash($key)};
return undef if !$data;
return $self->app->domain(name => $data->{name});
}
method head() {
return $self->metadata->{head};
}
method incr(Any @args) {
$self->throw(error_not_supported($self, 'incr'));
}
method hash(Str $key) {
require Digest::SHA; Digest::SHA::sha1_hex($key);
}
method pop(Any @args) {
$self->throw(error_not_supported($self, 'pop'));
}
method push(Any @args) {
$self->throw(error_not_supported($self, 'push'));
}
method restore(HashRef $data) {
return $self->{state} = {};
}
method set(Str $key) {
my $hash = $self->hash($key);
my $name = $key;
my $domain = $self->app->domain(name => $name);
my $prev = $self->apply->head;
if ($prev && $self->state->{$prev}) {
$self->change('set', $prev, {%{$self->state->{$prev}}, next => $hash});
}
$self->metadata->{head} = $hash;
$self->metadata->{tail} = $hash if !$self->metadata->{tail};
$self->change('set', $hash, {name => $name, next => undef, prev => $prev});
return $domain;
}
method shift(Any @args) {
$self->throw(error_not_supported($self, 'shift'));
}
method savepoint() {
return $self->app->savepoint(lookup => $self);
}
method snapshot() {
return {};
}
method tail() {
return $self->metadata->{tail};
}
method term() {
return $self->app->term($self)->lookup;
}
method unshift(Any @args) {
$self->throw(error_not_supported($self, 'unshift'));
}
# ERRORS
fun error_not_supported(Object $object, Str $method) {
code => 'error_not_implemented',
message => "@{[ref($object)]} method \"$method\" not supported",
}
1;
=encoding utf8
=head1 NAME
Zing::Lookup - Domain Lookup Table
=cut
=head1 ABSTRACT
Domain Lookup Table Construct
=cut
=head1 SYNOPSIS
use Zing::Lookup;
my $lookup = Zing::Lookup->new(name => 'users');
# my $domain = $lookup->set('unique-id');
=cut
=head1 DESCRIPTION
This package provides an index and lookup-table for L<Zing::Domain> data
structures which provides the ability to create a collection of domains with
full history of state changes.
=cut
=head1 INHERITS
This package inherits behaviors from:
L<Zing::Domain>
=cut
=head1 LIBRARIES
This package uses type constraints from:
L<Zing::Types>
=cut
=head1 METHODS
This package implements the following methods:
=cut
=head2 cursor
cursor() : Cursor
The cursor method returns a L<Zing::Cursor> object which provides the ability
to page-through and traverse the lookup dataset forwards and backwards.
=over 4
=item cursor example #1
# given: synopsis
$lookup->cursor;
=back
=cut
=head2 del
del(Str $key) : Lookup
The del method deletes the L<Zing::Domain> associated with a specific key.
=over 4
=item del example #1
# given: synopsis
$lookup->del('user-12345');
=back
=over 4
=item del example #2
# given: synopsis
$lookup->set('user-12345', 'me@example.com');
$lookup->del('user-12345');
=back
=cut
=head2 drop
drop() : Int
The drop method returns truthy if the lookup has been destroyed. This operation
does not cascade.
=over 4
=item drop example #1
# given: synopsis
$lookup->set('user-12345', 'me@example.com');
$lookup->drop;
=back
=over 4
=item drop example #2
# given: synopsis
$lookup->set('user-12345', 'me@example.com');
$lookup->savepoint->send;
$lookup->drop;
=back
=cut
=head2 get
get(Str $key) : Maybe[Domain]
The get method return the L<Zing::Domain> associated with a specific key.
=over 4
=item get example #1
# given: synopsis
$lookup->get('user-12345');
=back
=over 4
=item get example #2
# given: synopsis
$lookup->set('user-12345')->set(email => 'me@example.com');
$lookup->get('user-12345');
=back
=cut
=head2 savepoint
savepoint() : Savepoint
The savepoint method returns a L<Zing::Savepoint> object which provides the
ability to save and restore large indices (lookup states). If a lookup has an
associated savepoint it will be loaded automatically on object construction.
=over 4
=item savepoint example #1
# given: synopsis
$lookup->savepoint;
=back
=cut
=head2 set
set(Str $key) : Domain
The set method creates a L<Zing::Domain> association with a specific key in the
lookup. The key must be unique or will overwrite any existing data.
=over 4
=item set example #1
# given: synopsis
$lookup->del('user-12345');
$lookup->set('user-12345');
=back
=cut
=head1 AUTHOR
Al Newkirk, C<awncorp@cpan.org>
=head1 LICENSE
Copyright (C) 2011-2019, Al Newkirk, et al.
This is free software; you can redistribute it and/or modify it under the terms
of the The Apache License, Version 2.0, as elucidated in the L<"license
file"|https://github.com/cpanery/zing/blob/master/LICENSE>.
=head1 PROJECT
L<Wiki|https://github.com/cpanery/zing/wiki>
L<Project|https://github.com/cpanery/zing>
L<Initiatives|https://github.com/cpanery/zing/projects>
L<Milestones|https://github.com/cpanery/zing/milestones>
L<Contributing|https://github.com/cpanery/zing/blob/master/CONTRIBUTE.md>
L<Issues|https://github.com/cpanery/zing/issues>
=cut