File Coverage

blib/lib/TableDataRole/Source/Iterator.pm

Criterion	Covered	Total	%
statement	73	83	87.9
branch	18	36	50.0
condition	3	10	30.0
subroutine	13	15	86.6
pod	0	8	0.0
total	107	152	70.3

package TableDataRole::Source::Iterator;

use 5.010001;
use strict;
use warnings;

use Role::Tiny;

our $AUTHORITY = 'cpan:PERLANCAR'; # AUTHORITY
our $DATE = '2023-06-14'; # DATE
our $DIST = 'TableDataRoles-Standard'; # DIST
our $VERSION = '0.016'; # VERSION

with 'TableDataRole::Spec::Basic';

sub _new {
    my ($class, %args) = @_;

    my $gen_iterator = delete $args{gen_iterator} or die "Please specify 'gen_iterator' argument";
    my $gen_iterator_params = delete $args{gen_iterator_params} // {};

    die "Unknown argument(s): ". join(", ", sort keys %args)
        if keys %args;

    bless {
        gen_iterator => $gen_iterator,
        gen_iterator_params => $gen_iterator_params,
        iterator => undef,
        pos => 0,
        # buffer => undef,
        # column_names => undef,
        # column_idxs  => undef,
    }, $class;
}

sub _get_row {
    # get a row from iterator or buffer, and empty the buffer
    my $self = shift;
    if ($self->{buffer}) {
        my $row = delete $self->{buffer};
        if (!ref($row) && $row == -1) {
            return undef; ## no critic: Subroutines::ProhibitExplicitReturnUndef
        } else {
            return $row;
        }
    } else {
        $self->reset_iterator unless $self->{iterator};
        my $row = $self->{iterator}->();
        return undef unless $row; ## no critic: Subroutines::ProhibitExplicitReturnUndef
        return $row;
    }
}

sub _peek_row {
    # get a row from iterator, put it in buffer. will return the existing buffer
    # content if it exists.
    my $self = shift;
    unless ($self->{buffer}) {
        $self->reset_iterator unless $self->{iterator};
        $self->{buffer} = $self->{iterator}->() // -1;
    }
    if (!ref($self->{buffer}) && $self->{buffer} == -1) {
        return undef; ## no critic: Subroutines::ProhibitExplicitReturnUndef
    } else {
        return $self->{buffer};
    }
}

sub get_column_count {
    my $self = shift;
    $self->get_column_names;
    scalar(@{ $self->{column_names} });
}

sub get_column_names {
    my $self = shift;
    unless ($self->{column_names}) {
        my $row = $self->_peek_row;
        unless ($row) {
            return wantarray ? () : [];
        }
        my $i = -1;
        $self->{column_names} = [];
        $self->{column_idxs} = {};
        for (sort keys %$row) {
            push @{ $self->{column_names} }, $_;
            $self->{column_idxs}{$_} = ++$i;
        }
    }
    wantarray ? @{ $self->{column_names} } : $self->{column_names};
}

sub has_next_item {
    my $self = shift;
    $self->_peek_row ? 1:0;
}

sub get_next_item {
    my $self = shift;
    $self->get_column_names;
    my $row_hashref = $self->_get_row;
    die "StopIteration" unless $row_hashref;
    my $row_aryref = [];
    for (keys %$row_hashref) {
        my $idx = $self->{column_idxs}{$_};
        next unless defined $idx;
        $row_aryref->[$idx] = $row_hashref->{$_};
    }
    $self->{pos}++;
    $row_aryref;
}

sub get_next_row_hashref {
    my $self = shift;
    my $row_hashref = $self->_get_row;
    die "StopIteration" unless $row_hashref;
    $self->{pos}++;
    $row_hashref;
}

sub get_row_count {
    my $self = shift;
    $self->reset_iterator;
    unless (defined $self->{row_count}) {
        my $i = 0;
        $i++ while $self->_get_row;
        $self->{row_count} = $i;
    }
    $self->{row_count};
}

sub reset_iterator {
    my $self = shift;
    $self->{iterator} = $self->{gen_iterator}->(%{ $self->{gen_iterator_params} });
    delete $self->{buffer};
    $self->{pos} = 0;
}

sub get_iterator_pos {
    my $self = shift;
    $self->{pos};
}

1;
# ABSTRACT: Get table data from an iterator

__END__