Current File : C:/xampp/perl/vendor/lib/DBIx/Class/Storage/DBI/Cursor.pm
package DBIx::Class::Storage::DBI::Cursor;
use strict;
use warnings;
use base 'DBIx::Class::Cursor';
use Try::Tiny;
use Scalar::Util qw(refaddr weaken);
use List::Util 'shuffle';
use DBIx::Class::_Util 'detected_reinvoked_destructor';
use namespace::clean;
__PACKAGE__->mk_group_accessors('simple' =>
qw/storage args attrs/
);
=head1 NAME
DBIx::Class::Storage::DBI::Cursor - Object representing a query cursor on a
resultset.
=head1 SYNOPSIS
my $cursor = $schema->resultset('CD')->cursor();
# raw values off the database handle in resultset columns/select order
my @next_cd_column_values = $cursor->next;
# list of all raw values as arrayrefs
my @all_cds_column_values = $cursor->all;
=head1 DESCRIPTION
A Cursor represents a query cursor on a L<DBIx::Class::ResultSet> object. It
allows for traversing the result set with L</next>, retrieving all results with
L</all> and resetting the cursor with L</reset>.
Usually, you would use the cursor methods built into L<DBIx::Class::ResultSet>
to traverse it. See L<DBIx::Class::ResultSet/next>,
L<DBIx::Class::ResultSet/reset> and L<DBIx::Class::ResultSet/all> for more
information.
=head1 METHODS
=head2 new
Returns a new L<DBIx::Class::Storage::DBI::Cursor> object.
=cut
{
my %cursor_registry;
sub new {
my ($class, $storage, $args, $attrs) = @_;
my $self = bless {
storage => $storage,
args => $args,
attrs => $attrs,
}, ref $class || $class;
if (DBIx::Class::_ENV_::HAS_ITHREADS) {
# quick "garbage collection" pass - prevents the registry
# from slowly growing with a bunch of undef-valued keys
defined $cursor_registry{$_} or delete $cursor_registry{$_}
for keys %cursor_registry;
weaken( $cursor_registry{ refaddr($self) } = $self )
}
return $self;
}
sub CLONE {
for (keys %cursor_registry) {
# once marked we no longer care about them, hence no
# need to keep in the registry, left alone renumber the
# keys (all addresses are now different)
my $self = delete $cursor_registry{$_}
or next;
$self->{_intra_thread} = 1;
}
}
}
=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 next {
my $self = shift;
return if $self->{_done};
my $sth;
if (
$self->{attrs}{software_limit}
&& $self->{attrs}{rows}
&& ($self->{_pos}||0) >= $self->{attrs}{rows}
) {
if ($sth = $self->sth) {
# explicit finish will issue warnings, unlike the DESTROY below
$sth->finish if $sth->FETCH('Active');
}
$self->{_done} = 1;
return;
}
unless ($sth = $self->sth) {
(undef, $sth, undef) = $self->storage->_select( @{$self->{args}} );
$self->{_results} = [ (undef) x $sth->FETCH('NUM_OF_FIELDS') ];
$sth->bind_columns( \( @{$self->{_results}} ) );
if ( $self->{attrs}{software_limit} and $self->{attrs}{offset} ) {
$sth->fetch for 1 .. $self->{attrs}{offset};
}
$self->sth($sth);
}
if ($sth->fetch) {
$self->{_pos}++;
return @{$self->{_results}};
} else {
$self->{_done} = 1;
return ();
}
}
=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 all {
my $self = shift;
# delegate to DBIC::Cursor which will delegate back to next()
if ($self->{attrs}{software_limit}
&& ($self->{attrs}{offset} || $self->{attrs}{rows})) {
return $self->next::method(@_);
}
my $sth;
if ($sth = $self->sth) {
# explicit finish will issue warnings, unlike the DESTROY below
$sth->finish if ( ! $self->{_done} and $sth->FETCH('Active') );
$self->sth(undef);
}
(undef, $sth) = $self->storage->_select( @{$self->{args}} );
return (
DBIx::Class::_ENV_::SHUFFLE_UNORDERED_RESULTSETS
and
! $self->{attrs}{order_by}
)
? shuffle @{$sth->fetchall_arrayref}
: @{$sth->fetchall_arrayref}
;
}
sub sth {
my $self = shift;
if (@_) {
delete @{$self}{qw/_pos _done _pid _intra_thread/};
$self->{sth} = $_[0];
$self->{_pid} = $$ if ! DBIx::Class::_ENV_::BROKEN_FORK and $_[0];
}
elsif ($self->{sth} and ! $self->{_done}) {
my $invalidate_handle_reason;
if (DBIx::Class::_ENV_::HAS_ITHREADS and $self->{_intra_thread} ) {
$invalidate_handle_reason = 'Multi-thread';
}
elsif (!DBIx::Class::_ENV_::BROKEN_FORK and $self->{_pid} != $$ ) {
$invalidate_handle_reason = 'Multi-process';
}
if ($invalidate_handle_reason) {
$self->storage->throw_exception("$invalidate_handle_reason access attempted while cursor in progress (position $self->{_pos})")
if $self->{_pos};
# reinvokes the reset logic above
$self->sth(undef);
}
}
return $self->{sth};
}
=head2 reset
Resets the cursor to the beginning of the L<DBIx::Class::ResultSet>.
=cut
sub reset {
$_[0]->__finish_sth if $_[0]->{sth};
$_[0]->sth(undef);
}
sub DESTROY {
return if &detected_reinvoked_destructor;
$_[0]->__finish_sth if $_[0]->{sth};
}
sub __finish_sth {
# It is (sadly) extremely important to finish() handles we are about
# to lose (due to reset() or a DESTROY() ). $rs->reset is the closest
# thing the user has to getting to the underlying finish() API and some
# DBDs mandate this (e.g. DBD::InterBase will segfault, DBD::Sybase
# won't start a transaction sanely, etc)
# We also can't use the accessor here, as it will trigger a fork/thread
# check, and resetting a cursor in a child is perfectly valid
my $self = shift;
# No need to care about failures here
try { local $SIG{__WARN__} = sub {}; $self->{sth}->finish } if (
$self->{sth} and ! try { ! $self->{sth}->FETCH('Active') }
);
}
=head1 FURTHER QUESTIONS?
Check the list of L<additional DBIC resources|DBIx::Class/GETTING HELP/SUPPORT>.
=head1 COPYRIGHT AND LICENSE
This module is free software L<copyright|DBIx::Class/COPYRIGHT AND LICENSE>
by the L<DBIx::Class (DBIC) authors|DBIx::Class/AUTHORS>. You can
redistribute it and/or modify it under the same terms as the
L<DBIx::Class library|DBIx::Class/COPYRIGHT AND LICENSE>.
=cut
1;
Mini Shell