From: Peter Rabbitson <ribasushi@cpan.org>
Date: Thu, 4 Jun 2009 13:38:21 +0000 (+0000)
Subject: Really delegate counting to the storage class - now we have either a grouped count... 
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=7fc9269f5384a071cba4a212ca6c7321b25509ae;p=dbsrgits%2FDBIx-Class-Historic.git

Really delegate counting to the storage class - now we have either a grouped count or a regular one
---

diff --git a/lib/DBIx/Class/ResultSet.pm b/lib/DBIx/Class/ResultSet.pm
index bdd124a..ab04d69 100644
--- a/lib/DBIx/Class/ResultSet.pm
+++ b/lib/DBIx/Class/ResultSet.pm
@@ -1155,74 +1155,15 @@ sub count {
   return $self->search(@_)->count if @_ and defined $_[0];
   return scalar @{ $self->get_cache } if $self->get_cache;
 
-  my @grouped_subq_attrs = qw/prefetch collapse distinct group_by having/;
-  my @subq_attrs = ();
-  
-  my $attrs = $self->_resolved_attrs;
-  # if we are not paged - we are simply asking for a limit
-  if (not $attrs->{page} and not $attrs->{software_limit}) {
-    push @subq_attrs, qw/rows offset/;
-  }
-
-  my $need_subq = $self->_has_attr (@subq_attrs);
-  my $need_group_subq = $self->_has_attr (@grouped_subq_attrs);
-
-  return ($need_subq || $need_group_subq)
-    ? $self->_count_subq ($need_group_subq)
-    : $self->_count_simple
-}
-
-sub _count_subq {
-  my ($self, $add_group_by) = @_;
+  my $meth = $self->_has_attr (qw/prefetch collapse distinct group_by having/) 
+    ? 'count_grouped'
+    : 'count'
+  ;
 
   my $attrs = $self->_resolved_attrs_copy;
   my $rsrc = $self->result_source;
 
-  # copy for the subquery, we need to do some adjustments to it too
-  my $sub_attrs = { %$attrs };
-
-  # these can not go in the subquery, and there is no point of ordering it
-  delete $sub_attrs->{$_} for qw/prefetch collapse select +select as +as columns +columns order_by/;
-
-  # if needed force a group_by and the same set of columns (most databases require this)
-  if ($add_group_by) {
-
-    # if we prefetch, we group_by primary keys only as this is what we would get out of the rs via ->next/->all
-    # simply deleting group_by suffices, as the code below will re-fill it
-    # Note: we check $attrs, as $sub_attrs has collapse deleted
-    if (ref $attrs->{collapse} and keys %{$attrs->{collapse}} ) { 
-      delete $sub_attrs->{group_by};
-    }
-
-    $sub_attrs->{columns} = $sub_attrs->{group_by} ||= [ map { "$attrs->{alias}.$_" } ($rsrc->primary_columns) ];
-  }
-
-  $attrs->{from} = [{
-    count_subq => (ref $self)->new ($rsrc, $sub_attrs )->as_query
-  }];
-
-  # the subquery replaces this
-  delete $attrs->{$_} for qw/where bind prefetch collapse distinct group_by having having_bind/;
-
-  return $rsrc->storage->count ($rsrc, $attrs);
-}
-
-sub _count_simple {
-  my $self = shift;
-
-  my $rsrc = $self->result_source;
-
-  # the attrs supplied here are getting modified, do not reuse below
-  my $count = $rsrc->storage->count ($rsrc, $self->_resolved_attrs_copy);
-  return 0 unless $count;
-
-  # need to take offset from resolved attrs
-  my $attrs = $self->_resolved_attrs;
-
-  $count -= $attrs->{offset} if $attrs->{offset};
-  $count = $attrs->{rows} if $attrs->{rows} and $attrs->{rows} < $count;
-  $count = 0 if ($count < 0);
-  return $count;
+  return $rsrc->storage->$meth ($rsrc, $attrs);
 }
 
 sub _bool {
diff --git a/lib/DBIx/Class/Storage/DBI.pm b/lib/DBIx/Class/Storage/DBI.pm
index f7ba454..c20a931 100644
--- a/lib/DBIx/Class/Storage/DBI.pm
+++ b/lib/DBIx/Class/Storage/DBI.pm
@@ -1232,18 +1232,54 @@ sub _select_args {
 sub count {
   my ($self, $source, $attrs) = @_;
 
+  my $tmp_attrs = { %$attrs };
+
   # take off any column specs, any pagers, record_filter is cdbi, and no point of ordering a count
-  delete $attrs->{$_} for (qw/columns +columns select +select as +as rows offset page pager order_by record_filter/);
+  delete $tmp_attrs->{$_} for (qw/columns +columns select +select as +as rows offset page pager order_by record_filter/);
 
-  $attrs->{select} = { count => '*' };
-  $attrs->{as} = [qw/count/];
+  $tmp_attrs->{select} = { count => '*' };
+  $tmp_attrs->{as} = [qw/count/];
 
-  my $tmp_rs = $source->resultset_class->new($source, $attrs);
+  my $tmp_rs = $source->resultset_class->new($source, $tmp_attrs);
   my ($count) = $tmp_rs->cursor->next;
 
+  # if the offset/rows attributes are still present, we did not use
+  # a subquery, so we need to make the calculations in software
+  $count -= $attrs->{offset} if $attrs->{offset};
+  $count = $attrs->{rows} if $attrs->{rows} and $attrs->{rows} < $count;
+  $count = 0 if ($count < 0);
+
   return $count;
 }
 
+sub count_grouped {
+  my ($self, $source, $attrs) = @_;
+
+  # copy for the subquery, we need to do some adjustments to it too
+  my $sub_attrs = { %$attrs };
+
+  # these can not go in the subquery, and there is no point of ordering it
+  delete $sub_attrs->{$_} for qw/prefetch collapse select +select as +as columns +columns order_by/;
+
+  # if we prefetch, we group_by primary keys only as this is what we would get out of the rs via ->next/->all
+  # simply deleting group_by suffices, as the code below will re-fill it
+  # Note: we check $attrs, as $sub_attrs has collapse deleted
+  if (ref $attrs->{collapse} and keys %{$attrs->{collapse}} ) {
+    delete $sub_attrs->{group_by};
+  }
+
+  $sub_attrs->{columns} = $sub_attrs->{group_by} ||= [ map { "$attrs->{alias}.$_" } ($source->primary_columns) ];
+
+  $attrs->{from} = [{
+    count_subq => $source->resultset_class->new ($source, $sub_attrs )->as_query
+  }];
+
+  # the subquery replaces this
+  delete $attrs->{$_} for qw/where bind prefetch collapse distinct group_by having having_bind rows offset page pager/;
+
+  return $self->count ($source, $attrs);
+}
+
 sub source_bind_attributes {
   my ($self, $source) = @_;