X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDBIx%2FClass%2FStorage%2FDBI%2FCursor.pm;h=6681d23540d84cdb3652142c9fe4f899a24830cb;hb=3705e3b2801ea6a8f770b6f0c528b119bea92fe9;hp=87b0267102bccf5f9fe7e277cd5326a96cb0afff;hpb=28927b50e8ea9dbdf08a3ffeb9f1701f7b9fb99a;p=dbsrgits%2FDBIx-Class.git

diff --git a/lib/DBIx/Class/Storage/DBI/Cursor.pm b/lib/DBIx/Class/Storage/DBI/Cursor.pm
index 87b0267..6681d23 100644
--- a/lib/DBIx/Class/Storage/DBI/Cursor.pm
+++ b/lib/DBIx/Class/Storage/DBI/Cursor.pm
@@ -1,49 +1,248 @@
 package DBIx::Class::Storage::DBI::Cursor;
 
-use base qw/DBIx::Class::Cursor/;
-
 use strict;
 use warnings;
 
-sub new {
-  my ($it_class, $sth, $args, $attrs) = @_;
-  #use Data::Dumper; warn Dumper(@_);
-  $it_class = ref $it_class if ref $it_class;
-  my $new = {
-    sth => $sth,
-    args => $args,
-    pos => 0,
-    attrs => $attrs };
-  return bless ($new, $it_class);
+use base qw/DBIx::Class::Cursor/;
+
+use Try::Tiny;
+use Scalar::Util qw/refaddr weaken/;
+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) = @_;
-  return if $self->{attrs}{rows}
-    && $self->{pos} >= $self->{attrs}{rows}; # + $self->{attrs}{offset});
-  unless ($self->{live_sth}) {
-    $self->{sth}->execute(@{$self->{args} || []});
-    if (my $offset = $self->{attrs}{offset}) {
-      $self->{sth}->fetch for 1 .. $offset;
+  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 @{$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);
     }
-    $self->{live_sth} = 1;
   }
-  my @row = $self->{sth}->fetchrow_array;
-  $self->{pos}++ if @row;
-  return @row;
+
+  return $self->{sth};
 }
 
+=head2 reset
+
+Resets the cursor to the beginning of the L<DBIx::Class::ResultSet>.
+
+=cut
+
 sub reset {
-  my ($self) = @_;
-  $self->{sth}->finish if $self->{sth}->{Active};
-  $self->{pos} = 0;
-  $self->{live_sth} = 0;
-  return $self;
+  $_[0]->__finish_sth if $_[0]->{sth};
+  $_[0]->sth(undef);
 }
 
+
 sub DESTROY {
-  my ($self) = @_;
-  $self->{sth}->finish if $self->{sth}->{Active};
+  $_[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') }
+  );
 }
 
 1;