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lib/EntityModel/Resolver.pm  view on Meta::CPAN

package EntityModel::Resolver;
{
  $EntityModel::Resolver::VERSION = '0.102';
}
use EntityModel::Class;

=head2 import

Create the helper functions in the caller's namespace.

Takes the following named parameters:

=over 4

=item * model - the model to use for resolving entities

=back

=cut

sub import {
	my $class = shift;
	my %args = @_;
	my $model = $args{model} || EntityModel->default_model;
	my $pkg = (caller)[0];

	# Now we have a better idea of what we're doing, call through
	# to the various import helpers to do the real work
	$class->import_resolve(package => $pkg, model => $model);
}

=head2 import_resolve

Takes the following named parameters:

=over 4

=item * package - the package to install this helper function into

=item * model - the model to use for resolving entities

=back

Returns

=cut

{
my %active_resolutions;
sub import_resolve {
	my $class = shift;
	my %args = @_;
	my $pkg = $args{package} or die "No package provided";
	my $model = $args{model} or die "No model provided";
	my $code = sub (&;@) {
		my $request = shift;
		my $target = shift;
		my ($storage) = $model->storage->list or die "No storage found";
		# We'll build up the results in an array...
		my @rslt;
		# ... and a list of pending tasks so we can wait on them once we have
		# a clear idea of what we're waiting for.
		my @futures;

		# So the first step is to pull our list of key,value pairs from the
		# coderef, then we can go through those to start pulling data.
		my @pending = $request->();
		while(@pending) {
			# We expect (entity_name, keyfield_value) pairs
			my ($k, $v) = splice @pending, 0, 2;

			# Helps if we have an entity with a valid keyfield:
			my $entity = $model->entity_by_name($k) or die "Entity [$k] not found";
			die "No keyfield for $entity" unless defined $entity->keyfield;

			# Stash a placeholder value at the appropriate place in the output array,
			# and prepare a future to update it when we know what the real value is.
			# TODO Something about this just doesn't sit right with me.
			push @rslt, undef;
			my $idx = $#rslt;
			my $future = Future->new->on_ready(sub {
				($rslt[$idx]) = shift->get;
			});

			# Common handler to update our future when we have the value either through insert or find