X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDBIx%2FClass%2FOrdered.pm;h=0dd59a2c07d2deab9385246c28ce6a74fe9ce5c7;hb=9859bf7a4ab106f41a4373d8910a84f820e2fcf8;hp=409159eccd1c5bea1d1b10ec46cef4ad445b7895;hpb=e8fb771b9060f47eac9eaeef1d722cfe0dcfbe76;p=dbsrgits%2FDBIx-Class.git diff --git a/lib/DBIx/Class/Ordered.pm b/lib/DBIx/Class/Ordered.pm index 409159e..0dd59a2 100644 --- a/lib/DBIx/Class/Ordered.pm +++ b/lib/DBIx/Class/Ordered.pm @@ -3,6 +3,9 @@ use strict; use warnings; use base qw( DBIx::Class ); +use List::Util 'first'; +use namespace::clean; + =head1 NAME DBIx::Class::Ordered - Modify the position of objects in an ordered list. @@ -127,7 +130,7 @@ __PACKAGE__->mk_classdata( 'grouping_column' ); This method specifies a value of L which B during normal operation. When a row is moved, its position is set to this value temporarily, so -that any unique constrainst can not be violated. This value defaults +that any unique constraints can not be violated. This value defaults to 0, which should work for all cases except when your positions do indeed start from 0. @@ -364,33 +367,20 @@ sub move_to { my $position_column = $self->position_column; - my $guard; - if ($self->is_column_changed ($position_column) ) { - # something changed our position, we have no idea where we - # used to be - requery without using discard_changes - # (we need only a specific column back) - - $guard = $self->result_source->schema->txn_scope_guard; - - my $cursor = $self->result_source->resultset->search( - $self->ident_condition, - { select => $position_column }, - )->cursor; - - my ($pos) = $cursor->next; - $self->$position_column ($pos); + # something changed our position, we need to know where we + # used to be - use the stashed value + $self->store_column($position_column, delete $self->{_column_data_in_storage}{$position_column}); delete $self->{_dirty_columns}{$position_column}; } my $from_position = $self->_position; if ( $from_position == $to_position ) { # FIXME this will not work for non-numeric order - $guard->commit if $guard; return 0; } - $guard ||= $self->result_source->schema->txn_scope_guard; + my $guard = $self->result_source->schema->txn_scope_guard; my ($direction, @between); if ( $from_position < $to_position ) { @@ -447,28 +437,13 @@ sub move_to_group { return 0 if ( defined($to_position) and $to_position < 1 ); # check if someone changed the _grouping_columns - this will - # prevent _is_in_group working, so we need to requery the db - # for the original values - my (@dirty_cols, %values, $guard); + # prevent _is_in_group working, so we need to restore the + # original stashed values for ($self->_grouping_columns) { - $values{$_} = $self->get_column ($_); - push @dirty_cols, $_ if $self->is_column_changed ($_); - } - - # re-query only the dirty columns, and restore them on the - # object (subsequent code will update them to the correct - # after-move values) - if (@dirty_cols) { - $guard = $self->result_source->schema->txn_scope_guard; - - my $cursor = $self->result_source->resultset->search( - $self->ident_condition, - { select => \@dirty_cols }, - )->cursor; - - my @original_values = $cursor->next; - $self->set_inflated_columns ({ %values, map { $_ => shift @original_values } (@dirty_cols) }); - delete $self->{_dirty_columns}{$_} for (@dirty_cols); + if ($self->is_column_changed ($_)) { + $self->store_column($_, delete $self->{_column_data_in_storage}{$_}); + delete $self->{_dirty_columns}{$_}; + } } if ($self->_is_in_group ($to_group) ) { @@ -477,11 +452,10 @@ sub move_to_group { $ret = $self->move_to ($to_position); } - $guard->commit if $guard; return $ret||0; } - $guard ||= $self->result_source->schema->txn_scope_guard; + my $guard = $self->result_source->schema->txn_scope_guard; # Move to end of current group to adjust siblings $self->move_last; @@ -549,104 +523,52 @@ of a new group if it has been changed to undef. =cut sub update { - my $self = shift; - - # this is set by _ordered_internal_update() - return $self->next::method(@_) if $self->{_ORDERED_INTERNAL_UPDATE}; - - my $position_column = $self->position_column; - my @ordering_columns = ($self->_grouping_columns, $position_column); - - - # these steps are necessary to keep the external appearance of - # ->update($upd) so that other things overloading update() will - # work properly - my %original_values = $self->get_columns; - my %existing_changes = $self->get_dirty_columns; - - # See if any of the *supplied* changes would affect the ordering - # The reason this is so contrived, is that we want to leverage - # the datatype aware value comparing, while at the same time - # keep the original value intact (it will be updated later by the - # corresponding routine) - - my %upd = %{shift || {}}; - my %changes = %existing_changes; - - for (@ordering_columns) { - next unless exists $upd{$_}; - - # we do not want to keep propagating this to next::method - # as it will be a done deal by the time get there - my $value = delete $upd{$_}; - $self->set_inflated_columns ({ $_ => $value }); - - # see if an update resulted in a dirty column - # it is important to preserve the old value, as it - # will be needed to carry on a successfull move() - # operation without re-querying the database - if ($self->is_column_changed ($_) && not exists $existing_changes{$_}) { - $changes{$_} = $value; - $self->set_inflated_columns ({ $_ => $original_values{$_} }); - delete $self->{_dirty_columns}{$_}; - } - } - - # if nothing group/position related changed - short circuit - if (not grep { exists $changes{$_} } ( @ordering_columns ) ) { - return $self->next::method( \%upd, @_ ); - } - - { - my $guard = $self->result_source->schema->txn_scope_guard; - - # if any of our grouping columns have been changed - if (grep { exists $changes{$_} } ($self->_grouping_columns) ) { - - # create new_group by taking the current group and inserting changes - my $new_group = {$self->_grouping_clause}; - foreach my $col (keys %$new_group) { - $new_group->{$col} = $changes{$col} if exists $changes{$col}; - } - - $self->move_to_group( - $new_group, - (exists $changes{$position_column} - # The FIXME bit contradicts the documentation: POD states that - # when changing groups without supplying explicit positions in - # move_to_group(), we push the item to the end of the group. - # However when I was rewriting this, the position from the old - # group was clearly passed to the new one - # Probably needs to go away (by ribasushi) - ? $changes{$position_column} # means there was a position change supplied with the update too - : $self->_position # FIXME! (replace with undef) - ), - ); - } - elsif (exists $changes{$position_column}) { - $self->move_to($changes{$position_column}); - } - - my @res; - my $want = wantarray(); - if (not defined $want) { - $self->next::method( \%upd, @_ ); - } - elsif ($want) { - @res = $self->next::method( \%upd, @_ ); - } - else { - $res[0] = $self->next::method( \%upd, @_ ); - } + my $self = shift; + + # this is set by _ordered_internal_update() + return $self->next::method(@_) if $self->result_source->schema->{_ORDERED_INTERNAL_UPDATE}; + + my $upd = shift; + $self->set_inflated_columns($upd) if $upd; + + my $position_column = $self->position_column; + my @group_columns = $self->_grouping_columns; + + # see if the order is already changed + my $changed_ordering_cols = { map { $_ => $self->get_column($_) } grep { $self->is_column_changed($_) } ($position_column, @group_columns) }; + + # nothing changed - short circuit + if (! keys %$changed_ordering_cols) { + return $self->next::method( undef, @_ ); + } + elsif (defined first { exists $changed_ordering_cols->{$_} } @group_columns ) { + $self->move_to_group( + # since the columns are already re-set the _grouping_clause is correct + # move_to_group() knows how to get the original storage values + { $self->_grouping_clause }, + + # The FIXME bit contradicts the documentation: POD states that + # when changing groups without supplying explicit positions in + # move_to_group(), we push the item to the end of the group. + # However when I was rewriting this, the position from the old + # group was clearly passed to the new one + # Probably needs to go away (by ribasushi) + (exists $changed_ordering_cols->{$position_column} + ? $changed_ordering_cols->{$position_column} # means there was a position change supplied with the update too + : $self->_position # FIXME! (replace with undef) + ), + ); + } + else { + $self->move_to($changed_ordering_cols->{$position_column}); + } - $guard->commit; - return $want ? @res : $res[0]; - } + return $self; } =head2 delete -Overrides the DBIC delete() method by first moving the object +Overrides the DBIC delete() method by first moving the object to the last position, then deleting it, thus ensuring the integrity of the positions. @@ -660,11 +582,10 @@ sub delete { $self->move_last; my @res; - my $want = wantarray(); - if (not defined $want) { + if (not defined wantarray) { $self->next::method( @_ ); } - elsif ($want) { + elsif (wantarray) { @res = $self->next::method( @_ ); } else { @@ -672,7 +593,13 @@ sub delete { } $guard->commit; - return $want ? @res : $res[0]; + return wantarray ? @res : $res[0]; +} + +# add the current position/group to the things we track old values for +sub _track_storage_value { + my ($self, $col) = @_; + return $self->next::method($col) || defined first { $_ eq $col } ($self->position_column, $self->_grouping_columns); } =head1 METHODS FOR EXTENDING ORDERED @@ -761,11 +688,11 @@ sub _next_position_value { Shifts all siblings with B in the range @between (inclusive) by one position as specified by $direction (left if < 0, right if > 0). By default simply increments/decrements each -L value by 1, doing so in a way as to not violate +L value by 1, doing so in a way as to not violate any existing constraints. Note that if you override this method and have unique constraints -including the L the shift is not a trivial task. +including the L the shift is not a trivial task. Refer to the implementation source of the default method for more information. @@ -792,23 +719,36 @@ sub _shift_siblings { # increment/decrement. So what we do here is check if the # position column is part of a unique constraint, and do a # one-by-one update if this is the case + # Also we do a one-by-one if the position is part of the PK + # since once we update a column via scalarref we lose the + # ability to retrieve this column back (we do not know the + # id anymore) my $rsrc = $self->result_source; - if (grep { $_ eq $position_column } ( map { @$_ } (values %{{ $rsrc->unique_constraints }} ) ) ) { - - my @pcols = $rsrc->_pri_cols; - my $cursor = $shift_rs->search ({}, { order_by => { "-$ord", $position_column }, columns => \@pcols } )->cursor; + # set in case there are more cascades combined with $rs->update => $rs_update_all overrides + local $rsrc->schema->{_ORDERED_INTERNAL_UPDATE} = 1; + my @pcols = $rsrc->primary_columns; + my $pos_is_pk = first { $_ eq $position_column } @pcols; + if ( + $pos_is_pk + or + first { $_ eq $position_column } ( map { @$_ } (values %{{ $rsrc->unique_constraints }} ) ) + ) { + my $cursor = $shift_rs->search ( + {}, { order_by => { "-$ord", $position_column }, select => [$position_column, @pcols] } + )->cursor; my $rs = $self->result_source->resultset; - my @all_pks = $cusrsor->all; - while (my $pks = shift @all_pks) { + my @all_data = $cursor->all; + while (my $data = shift @all_data) { + my $pos = shift @$data; my $cond; for my $i (0.. $#pcols) { - $cond->{$pcols[$i]} = $pks->[$i]; + $cond->{$pcols[$i]} = $data->[$i]; } - $rs->search($cond)->update ({ $position_column => \ "$position_column $op 1" } ); + $rs->find($cond)->update ({ $position_column => $pos + ( ($op eq '+') ? 1 : -1 ) }); } } else { @@ -841,9 +781,13 @@ excluding the object you called this method on. sub _siblings { my $self = shift; my $position_column = $self->position_column; - return $self->_group_rs->search( - { $position_column => { '!=' => $self->get_column($position_column) } }, - ); + my $pos; + return defined ($pos = $self->get_column($position_column)) + ? $self->_group_rs->search( + { $position_column => { '!=' => $pos } }, + ) + : $self->_group_rs + ; } =head2 _position @@ -921,7 +865,7 @@ module to update positioning values in isolation (i.e. without triggering any of the positioning integrity code). Some day you might get confronted by datasets that have ambiguous -positioning data (i.e. duplicate position values within the same group, +positioning data (e.g. duplicate position values within the same group, in a table without unique constraints). When manually fixing such data keep in mind that you can not invoke L like you normally would, as it will get confused by the wrong data before @@ -933,7 +877,7 @@ this module. sub _ordered_internal_update { my $self = shift; - local $self->{_ORDERED_INTERNAL_UPDATE} = 1; + local $self->result_source->schema->{_ORDERED_INTERNAL_UPDATE} = 1; return $self->update (@_); } @@ -943,9 +887,23 @@ __END__ =head1 CAVEATS +=head2 Resultset Methods + +Note that all Insert/Create/Delete overrides are happening on +L methods only. If you use the +L versions of +L or +L, all logic present in this +module will be bypassed entirely (possibly resulting in a broken +order-tree). Instead always use the +L and +L methods, which will +invoke the corresponding L method on every +member of the given resultset. + =head2 Race Condition on Insert -If a position is not specified for an insert than a position +If a position is not specified for an insert, a position will be chosen based either on L or L, depending if there are already some items in the current group. The space of time between the @@ -956,14 +914,14 @@ will prevent such race conditions going undetected. =head2 Multiple Moves -Be careful when issueing move_* methods to multiple objects. If +Be careful when issuing move_* methods to multiple objects. If you've pre-loaded the objects then when you move one of the objects the position of the other object will not reflect their new value until you reload them from the database - see L. There are times when you will want to move objects as groups, such -as changeing the parent of several objects at once - this directly +as changing the parent of several objects at once - this directly conflicts with this problem. One solution is for us to write a ResultSet class that supports a parent() method, for example. Another solution is to somehow automagically modify the objects that exist