Refactor SQLA/select interaction (in reality just cleanup)

[dbsrgits/DBIx-Class.git] / lib / DBIx / Class / Storage / DBI / Cursor.pm

diff --git a/lib/DBIx/Class/Storage/DBI/Cursor.pm b/lib/DBIx/Class/Storage/DBI/Cursor.pm
index 5334589..875a3cb 100644 (file)
--- a/lib/DBIx/Class/Storage/DBI/Cursor.pm
+++ b/lib/DBIx/Class/Storage/DBI/Cursor.pm
@@ -1,103 +1,183 @@
-package # hide from PAUSE 
-    DBIx::Class::Storage::DBI::Cursor;
-
-use base qw/DBIx::Class::Cursor/;
+package DBIx::Class::Storage::DBI::Cursor;
 
 use strict;
 use warnings;
 
+use base qw/DBIx::Class::Cursor/;
+
+__PACKAGE__->mk_group_accessors('simple' =>
+    qw/sth/
+);
+
+=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,
-    pid => $$,
+    _dbh_gen => $storage->{_dbh_gen},
   };
 
-  $new->{tid} = threads->tid if $INC{'threads.pm'};
-  
   return bless ($new, $class);
 }
 
-sub next {
-  my ($self) = @_;
+=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
 
-  $self->_check_forks_threads;
-  if ($self->{attrs}{rows} && $self->{pos} >= $self->{attrs}{rows}) {
-    $self->{sth}->finish if $self->{sth}->{Active};
-    delete $self->{sth};
+sub _dbh_next {
+  my ($storage, $dbh, $self) = @_;
+
+  $self->_check_dbh_gen;
+  if (
+    $self->{attrs}{software_limit}
+      && $self->{attrs}{rows}
+        && $self->{pos} >= $self->{attrs}{rows}
+  ) {
+    $self->sth->finish if $self->sth->{Active};
+    $self->sth(undef);
     $self->{done} = 1;
   }
   return if $self->{done};
-  unless ($self->{sth}) {
-    $self->{sth} = ($self->{storage}->_select(@{$self->{args}}))[1];
+  unless ($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;
+        $self->sth->fetch for 1 .. $offset;
       }
     }
   }
-  my @row = $self->{sth}->fetchrow_array;
+  my @row = $self->sth->fetchrow_array;
   if (@row) {
     $self->{pos}++;
   } else {
-    delete $self->{sth};
+    $self->sth(undef);
     $self->{done} = 1;
   }
   return @row;
 }
 
-sub all {
+sub next {
   my ($self) = @_;
+  $self->{storage}->dbh_do($self->can('_dbh_next'), $self);
+}
+
+=head2 all
+
+=over 4
+
+=item Arguments: none
 
-  $self->_check_forks_threads;
-  return $self->SUPER::all if $self->{attrs}{rows};
-  $self->{sth}->finish if $self->{sth}->{Active};
-  delete $self->{sth};
-  my ($rv, $sth) = $self->{storage}->_select(@{$self->{args}});
+=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 && $self->sth->{Active};
+  $self->sth(undef);
+  my ($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->next::method;
+  }
+
+  $self->{storage}->dbh_do($self->can('_dbh_all'), $self);
+}
+
+=head2 reset
+
+Resets the cursor to the beginning of the L<DBIx::Class::ResultSet>.
+
+=cut
+
 sub reset {
   my ($self) = @_;
 
-  $self->_check_forks_threads;
-  $self->{sth}->finish if $self->{sth}->{Active};
+  # No need to care about failures here
+  eval { $self->sth->finish if $self->sth && $self->sth->{Active} };
   $self->_soft_reset;
+  return undef;
 }
 
 sub _soft_reset {
   my ($self) = @_;
 
-  delete $self->{sth};
-  $self->{pos} = 0;
+  $self->sth(undef);
   delete $self->{done};
-  return $self;
+  $self->{pos} = 0;
 }
 
-sub _check_forks_threads {
+sub _check_dbh_gen {
   my ($self) = @_;
 
-  if($INC{'threads.pm'} && $self->{tid} != threads->tid) {
-      $self->_soft_reset;
-      $self->{tid} = threads->tid;
-  }
-
-  if($self->{pid} != $$) {
-      $self->_soft_reset;
-      $self->{pid} = $$;
+  if($self->{_dbh_gen} != $self->{storage}->{_dbh_gen}) {
+    $self->{_dbh_gen} = $self->{storage}->{_dbh_gen};
+    $self->_soft_reset;
   }
 }
 
 sub DESTROY {
   my ($self) = @_;
 
-  $self->_check_forks_threads;
-  $self->{sth}->finish if $self->{sth}->{Active};
+  # 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;