扩展Mojo：：承诺

Question

第一次招贴画，温柔点。

我想要类似于Mojo：：诺言->all的东西，除了有一个选项放弃某些被拒绝的(或者，我猜是已解决的)承诺依赖于拒绝值，这是由调用者决定的。

只在内部使用这个，所以不用担心我污染了Mojo：：诺言：：命名空间。

package Mojo::Promise::Filter;
use Moose;

extends 'Mojo::Promise';

has 'promises' => (
    isa => 'ArrayRef[Mojo::Promise]',
    is => 'ro',
    required => 1,
);

has 'resolve_filter' => ( # truthy return means *DO* filter out
    isa => 'CodeRef',
    is => 'ro',
    required => 1,
    lazy => 1,
    default => sub { return sub {}; },
);

has 'reject_filter' => ( # truthy return means *DO* filter out
    isa => 'CodeRef',
    is => 'ro',
    required => 1,
    lazy => 1,
    default => sub { return sub {}; },
);

has '_promises_state_tracker' => (
    # numbered hashref whose primary keys correspond to passed promise-array's indices
    # secondary keys are flags for whether each original promise filtered
    # and whether promise resolved/rejected,
    # plus the original promise itself, e.g. : 
    # { 0 => { filtered => (undef|1), ror => (undef|1), original_promise => (Mojo::Promise) } }
    isa => 'HashRef[HashRef]',
    is => 'ro',
    lazy => 1,
    builder => '_build_promises_state_tracker',
);


sub _build_promises_state_tracker {
    my $self = shift;
    my $i = 0;
    return { map { $i++ => { original_promise => $_ } } @{$self->promises} };
}

sub _resolve_or_reject_self_if_last_child {
    my $self = shift;

    my @ror = grep { $_->{ror} } values %{$self->_promises_state_tracker};
        # gather the thus-far resolved-or-rejected promises
    return unless scalar keys %{$self->_promises_state_tracker} == scalar @ror;
        # return unless we have as many ror promises as were passed in

    my @unfiltered = map { $_->{original_promise} } grep { !$_->{filtered} } values %{$self->_promises_state_tracker};
    return Mojo::Promise->all(@unfiltered)->then(sub {
        $self->resolve(@_)
    })->catch(sub {
        $self->reject(@_)
    });
}

sub filter {
    my $self = shift;

    for my $i (0 .. $#{$self->promises}) {
        $self->promises->[$i]->then(sub {
            $self->_promises_state_tracker->{$i}->{filtered} = 1
                if $self->resolve_filter->(@_);
        })->catch(sub {
            $self->_promises_state_tracker->{$i}->{filtered} = 1
                if $self->reject_filter->(@_);
        })->finally(sub {
            $self->_promises_state_tracker->{$i}->{ror} = 1;
                # ror = Resolved Or Rejected
            $self->_resolve_or_reject_self_if_last_child();
        });
    }

    return $self;
}

no Moose;

1;

用作：

my $re_filter = qr/some special text/;
my $reject_filter = sub {
        my $v = shift;
        return 1 if ref \$v eq 'SCALAR' && $v =~ $re_filter;
    };

my $p = Mojo::Promise::Filter->new(
        reject_filter => $reject_filter,
        promises => \@promises
    );

return $p->filter;

Answer 1

莫灼里已经有角色了。

 package Mojo::Promise::Role::Filter {
     use Mojo::Base '-role';
     ...; # stuff you want in the Promise class
     }

 my $promise->with_roles( '+Filter' )->new;
 ...;

参见，例如，莫霍：：承诺：：角色：：任何。