From: Norbert Buchmuller <norbi@nix.hu>
Date: Sat, 15 Nov 2008 03:18:53 +0000 (+0100)
Subject:  * Added ->first and ->reset implementation to ResultSetColumn.
X-Git-Tag: v0.08240~237^2~2
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?p=dbsrgits%2FDBIx-Class.git;a=commitdiff_plain;h=66521001058c038fdd23f9a0b304acac381d04e7

 * Added ->first and ->reset implementation to ResultSetColumn.
 * A bit of refactoring/cleanup of ResultSetColumn.
---

diff --git a/lib/DBIx/Class/ResultSetColumn.pm b/lib/DBIx/Class/ResultSetColumn.pm
index 3780853..3585d17 100644
--- a/lib/DBIx/Class/ResultSetColumn.pm
+++ b/lib/DBIx/Class/ResultSetColumn.pm
@@ -2,7 +2,7 @@ package DBIx::Class::ResultSetColumn;
 use strict;
 use warnings;
 use base 'DBIx::Class';
-use List::Util qw(first);
+use List::Util;
 
 =head1 NAME
 
@@ -41,7 +41,7 @@ sub new {
   $new_parent_rs->{attrs}->{$_} = undef for qw(prefetch include_columns +select +as); # prefetch, include_columns, +select, +as cause additional columns to be fetched
   my ($select, $as) =
     map { defined $_ ? ($attrs->{select}->[$_], $attrs->{as}->[$_]) : ($column, $column) }
-      first { ($attrs->{as} || [])->[$_] eq $column }
+      List::Util::first { ($attrs->{as} || [])->[$_] eq $column }
         0..$#{$attrs->{as} || []};
   my $new = bless { _select => $select, _as => $as, _parent_resultset => $new_parent_rs }, $class;
   $new->throw_exception("column must be supplied") unless $column;
@@ -68,8 +68,7 @@ one value.
 
 sub next {
   my $self = shift;
-  $self->{_resultset} = $self->{_parent_resultset}->search(undef, {select => [$self->{_select}], as => [$self->{_as}]}) unless ($self->{_resultset});
-  my ($row) = $self->{_resultset}->cursor->next;
+  my ($row) = $self->_resultset->cursor->next;
   return $row;
 }
 
@@ -93,7 +92,53 @@ than row objects.
 
 sub all {
   my $self = shift;
-  return map {$_->[0]} $self->{_parent_resultset}->search(undef, {select => [$self->{_select}], as => [$self->{_as}]})->cursor->all;
+  return map { $_->[0] } $self->_resultset->cursor->all;
+}
+
+=head2 reset
+
+=over 4
+
+=item Arguments: none
+
+=item Return Value: $self
+
+=back
+
+Resets the underlying resultset's cursor, so you can iterate through the
+elements of the column again.
+
+Much like L<DBIx::Class::ResultSet/reset>.
+
+=cut
+
+sub reset {
+  my $self = shift;
+  $self->_resultset->cursor->reset;
+  return $self;
+}
+
+=head2 first
+
+=over 4
+
+=item Arguments: none
+
+=item Return Value: $value
+
+=back
+
+Resets the underlying resultset and returns the next value of the column in the
+resultset (or C<undef> if there is none).
+
+Much like L<DBIx::Class::ResultSet/first> but just returning the one value.
+
+=cut
+
+sub first {
+  my $self = shift;
+  my ($row) = $self->{_resultset}->cursor->reset->next;
+  return $row;
 }
 
 =head2 min
@@ -205,6 +250,34 @@ sub throw_exception {
   }
 }
 
+=head2 _resultset
+
+=over 4
+
+=item Arguments: none
+
+=item Return Value: $resultset
+
+=back
+
+  $year_col->_resultset->next
+
+Returns the underlying resultset. Creates it from the parent resultset if
+necessary.
+
+=cut
+
+sub _resultset {
+  my $self = shift;
+
+  return $self->{_resultset} ||= $self->{_parent_resultset}->search(undef,
+    {
+      select => [$self->{_select}],
+      as => [$self->{_as}]
+    }
+  );
+}
+
 
 1;
 
diff --git a/t/88result_set_column.t b/t/88result_set_column.t
index 67262f0..66169f3 100644
--- a/t/88result_set_column.t
+++ b/t/88result_set_column.t
@@ -8,10 +8,10 @@ use DBICTest;
 
 my $schema = DBICTest->init_schema();
 
-plan tests => 16;
+plan tests => 18;
 
 my $cd;
-my $rs = $cd = $schema->resultset("CD")->search({});
+my $rs = $cd = $schema->resultset("CD")->search({}, { order_by => 'cdid' });
 
 my $rs_title = $rs->get_column('title');
 my $rs_year = $rs->get_column('year');
@@ -29,6 +29,11 @@ is($rs_title->min, 'Caterwaulin\' Blues', "min okay for title");
 
 cmp_ok($rs_year->sum, '==', 9996, "three artists returned");
 
+$rs_year->reset;
+is($rs_year->next, 1999, "reset okay");
+
+is($rs_year->first, 1999, "first okay");
+
 # test +select/+as for single column
 my $psrs = $schema->resultset('CD')->search({},
     {