package DBIx::Class::Storage::DBI::Cursor;
use base qw/DBIx::Class::Cursor/;
use strict;
use warnings;
=head1 NAME
DBIx::Class::Storage::DBI::Cursor - Object representing a query cursor on a
resultset.
=head1 SYNOPSIS
my $cursor = $schema->resultset('CD')->cursor();
my $first_cd = $cursor->next;
=head1 DESCRIPTION
A Cursor represents a query cursor on a L<DBIx::Class::ResultSet> object. It
allows for traversing the result set with L</next>, retrieving all results with
L</all> and resetting the cursor with L</reset>.
Usually, you would use the cursor methods built into L<DBIx::Class::ResultSet>
to traverse it. See L<DBIx::Class::ResultSet/next>,
L<DBIx::Class::ResultSet/reset> and L<DBIx::Class::ResultSet/all> for more
information.
=head1 METHODS
=head2 new
Returns a new L<DBIx::Class::Storage::DBI::Cursor> object.
=cut
sub new {
my ($class, $storage, $args, $attrs) = @_;
#use Data::Dumper; warn Dumper(@_);
$class = ref $class if ref $class;
my $new = {
storage => $storage,
args => $args,
pos => 0,
attrs => $attrs,
_dbh_gen => $storage->{_dbh_gen},
};
return bless ($new, $class);
}
=head2 as_query
=over 4
=item Arguments: none
=item Return Value: \[ $sql, @bind ]
=back
Returns the SQL statement and bind vars associated with the invocant.
=cut
sub as_query {
my $self = shift;
my $storage = $self->{storage};
my $sql_maker = $storage->sql_maker;
local $sql_maker->{for};
my @args = $storage->_select_args(@{$self->{args}});
my ($sql, $bind) = $storage->_prep_for_execute(@args[0 .. 2], [@args[4 .. $#args]]);
return \[ "($sql)", @$bind ];
}
=head2 next
=over 4
=item Arguments: none
=item Return Value: \@row_columns
=back
Advances the cursor to the next row and returns an array of column
values (the result of L<DBI/fetchrow_array> method).
=cut
sub _dbh_next {
my ($storage, $dbh, $self) = @_;
$self->_check_dbh_gen;
if ($self->{attrs}{rows} && $self->{pos} >= $self->{attrs}{rows}) {
$self->{sth}->finish if $self->{sth}->{Active};
delete $self->{sth};
$self->{done} = 1;
}
return if $self->{done};
unless ($self->{sth}) {
$self->{sth} = ($storage->_select(@{$self->{args}}))[1];
if ($self->{attrs}{software_limit}) {
if (my $offset = $self->{attrs}{offset}) {
$self->{sth}->fetch for 1 .. $offset;
}
}
}
my @row = $self->{sth}->fetchrow_array;
if (@row) {
$self->{pos}++;
} else {
delete $self->{sth};
$self->{done} = 1;
}
return @row;
}
sub next {
my ($self) = @_;
$self->{storage}->dbh_do($self->can('_dbh_next'), $self);
}
=head2 all
=over 4
=item Arguments: none
=item Return Value: \@row_columns+
=back
Returns a list of arrayrefs of column values for all rows in the
L<DBIx::Class::ResultSet>.
=cut
sub _dbh_all {
my ($storage, $dbh, $self) = @_;
$self->_check_dbh_gen;
$self->{sth}->finish if $self->{sth}->{Active};
delete $self->{sth};
my ($rv, $sth) = $storage->_select(@{$self->{args}});
return @{$sth->fetchall_arrayref};
}
sub all {
my ($self) = @_;
if ($self->{attrs}{software_limit}
&& ($self->{attrs}{offset} || $self->{attrs}{rows})) {
return $self->SUPER::all;
}
$self->{storage}->dbh_do($self->can('_dbh_all'), $self);
}
=head2 reset
Resets the cursor to the beginning of the L<DBIx::Class::ResultSet>.
=cut
sub reset {
my ($self) = @_;
# No need to care about failures here
eval { $self->{sth}->finish if $self->{sth} && $self->{sth}->{Active} };
$self->_soft_reset;
}
sub _soft_reset {
my ($self) = @_;
delete $self->{sth};
delete $self->{done};
$self->{pos} = 0;
return $self;
}
sub _check_dbh_gen {
my ($self) = @_;
if($self->{_dbh_gen} != $self->{storage}->{_dbh_gen}) {
$self->{_dbh_gen} = $self->{storage}->{_dbh_gen};
$self->_soft_reset;
}
}
sub DESTROY {
my ($self) = @_;
# None of the reasons this would die matter if we're in DESTROY anyways
local $@;
eval { $self->{sth}->finish if $self->{sth} && $self->{sth}->{Active} };
}
1;