X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDBIx%2FClass%2FOrdered.pm;h=0b4384ba5475dda62abe77dd2f84e491152dad87;hb=8273e845426f0187b4ad6c4a1b42286fa09a648f;hp=6566f7b284c82d3dcfe6b99c6182ee7ef3dc82c0;hpb=b250066fcc924b2604fc964c78339f384269ac72;p=dbsrgits%2FDBIx-Class.git diff --git a/lib/DBIx/Class/Ordered.pm b/lib/DBIx/Class/Ordered.pm index 6566f7b..0b4384b 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. @@ -17,7 +20,7 @@ Create a table for your ordered data. position INTEGER NOT NULL ); -Optionally, add one or more columns to specify groupings, allowing you +Optionally, add one or more columns to specify groupings, allowing you to maintain independent ordered lists within one table: CREATE TABLE items ( @@ -37,12 +40,12 @@ Or even other_group_id INTEGER NOT NULL ); -In your Schema or DB class add "Ordered" to the top +In your Schema or DB class add "Ordered" to the top of the component list. __PACKAGE__->load_components(qw( Ordered ... )); -Specify the column that stores the position number for +Specify the column that stores the position number for each row. package My::Item; @@ -60,20 +63,20 @@ That's it, now you can change the position of your objects. #!/use/bin/perl use My::Item; - + my $item = My::Item->create({ name=>'Matt S. Trout' }); # If using grouping_column: my $item = My::Item->create({ name=>'Matt S. Trout', group_id=>1 }); - + my $rs = $item->siblings(); my @siblings = $item->siblings(); - + my $sibling; $sibling = $item->first_sibling(); $sibling = $item->last_sibling(); $sibling = $item->previous_sibling(); $sibling = $item->next_sibling(); - + $item->move_previous(); $item->move_next(); $item->move_first(); @@ -86,13 +89,13 @@ That's it, now you can change the position of your objects. =head1 DESCRIPTION -This module provides a simple interface for modifying the ordered +This module provides a simple interface for modifying the ordered position of DBIx::Class objects. =head1 AUTO UPDATE -All of the move_* methods automatically update the rows involved in -the query. This is not configurable and is due to the fact that if you +All of the move_* methods automatically update the rows involved in +the query. This is not configurable and is due to the fact that if you move a record it always causes other records in the list to be updated. =head1 METHODS @@ -101,7 +104,7 @@ move a record it always causes other records in the list to be updated. __PACKAGE__->position_column('position'); -Sets and retrieves the name of the column that stores the +Sets and retrieves the name of the column that stores the positional value of each record. Defaults to "position". =cut @@ -112,8 +115,8 @@ __PACKAGE__->mk_classdata( 'position_column' => 'position' ); __PACKAGE__->grouping_column('group_id'); -This method specifies a column to limit all queries in -this module by. This effectively allows you to have multiple +This method specifies a column to limit all queries in +this module by. This effectively allows you to have multiple ordered lists within the same table. =cut @@ -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. @@ -215,7 +218,7 @@ sub previous_sibling { my $sibling = $item->first_sibling(); -Returns the first sibling object, or 0 if the first sibling +Returns the first sibling object, or 0 if the first sibling is this sibling. =cut @@ -256,7 +259,7 @@ sub next_sibling { my $sibling = $item->last_sibling(); -Returns the last sibling, or 0 if the last sibling is this +Returns the last sibling, or 0 if the last sibling is this sibling. =cut @@ -272,6 +275,20 @@ sub last_sibling { return defined $lsib ? $lsib : 0; } +# an optimized method to get the last sibling position value without inflating a row object +sub _last_sibling_posval { + my $self = shift; + my $position_column = $self->position_column; + + my $cursor = $self->next_siblings->search( + {}, + { rows => 1, order_by => { '-desc' => $position_column }, select => $position_column }, + )->cursor; + + my ($pos) = $cursor->next; + return $pos; +} + =head2 move_previous $item->move_previous(); @@ -299,7 +316,7 @@ the last in the list. sub move_next { my $self = shift; - return 0 unless $self->next_siblings->count; + return 0 unless defined $self->_last_sibling_posval; # quick way to check for no more siblings return $self->move_to ($self->_position + 1); } @@ -327,7 +344,11 @@ on success, and 0 if the object is already the last one. sub move_last { my $self = shift; - return $self->move_to( $self->_group_rs->count ); + my $last_posval = $self->_last_sibling_posval; + + return 0 unless defined $last_posval; + + return $self->move_to( $self->_position_from_value ($last_posval) ); } =head2 move_to @@ -344,35 +365,45 @@ sub move_to { my( $self, $to_position ) = @_; return 0 if ( $to_position < 1 ); - my $from_position = $self->_position; - return 0 if ( $from_position == $to_position ); - my $position_column = $self->position_column; - # FIXME this needs to be wrapped in a transaction - { - my ($direction, @between); - if ( $from_position < $to_position ) { - $direction = -1; - @between = map { $self->_position_value ($_) } ( $from_position + 1, $to_position ); - } - else { - $direction = 1; - @between = map { $self->_position_value ($_) } ( $to_position, $from_position - 1 ); - } + if ($self->is_column_changed ($position_column) ) { + # 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; - my $new_pos_val = $self->_position_value ($to_position); # record this before the shift + if ( $from_position == $to_position ) { # FIXME this will not work for non-numeric order + return 0; + } - # we need to null-position the moved row if the position column is part of a constraint - if (grep { $_ eq $position_column } ( map { @$_ } (values %{{ $self->result_source->unique_constraints }} ) ) ) { - $self->_ordered_internal_update({ $position_column => $self->null_position_value }); - } + my $guard = $self->result_source->schema->txn_scope_guard; - $self->_shift_siblings ($direction, @between); - $self->_ordered_internal_update({ $position_column => $new_pos_val }); + my ($direction, @between); + if ( $from_position < $to_position ) { + $direction = -1; + @between = map { $self->_position_value ($_) } ( $from_position + 1, $to_position ); + } + else { + $direction = 1; + @between = map { $self->_position_value ($_) } ( $to_position, $from_position - 1 ); + } - return 1; + my $new_pos_val = $self->_position_value ($to_position); # record this before the shift + + # we need to null-position the moved row if the position column is part of a constraint + if (grep { $_ eq $position_column } ( map { @$_ } (values %{{ $self->result_source->unique_constraints }} ) ) ) { + $self->_ordered_internal_update({ $position_column => $self->null_position_value }); } + + $self->_shift_siblings ($direction, @between); + $self->_ordered_internal_update({ $position_column => $new_pos_val }); + + $guard->commit; + return 1; } =head2 move_to_group @@ -384,7 +415,7 @@ group, or to the end of the group if $position is undef. 1 is returned on success, and 0 is returned if the object is already at the specified position of the specified group. -$group may be specified as a single scalar if only one +$group may be specified as a single scalar if only one grouping column is in use, or as a hashref of column => value pairs if multiple grouping columns are in use. @@ -393,10 +424,7 @@ if multiple grouping columns are in use. sub move_to_group { my( $self, $to_group, $to_position ) = @_; - $self->throw_exception ('move_to_group() expects a group specification') - unless defined $to_group; - - # if we're given a string, turn it into a hashref + # if we're given a single value, turn it into a hashref unless (ref $to_group eq 'HASH') { my @gcols = $self->_grouping_columns; @@ -407,43 +435,62 @@ sub move_to_group { my $position_column = $self->position_column; return 0 if ( defined($to_position) and $to_position < 1 ); - if ($self->_is_in_group ($to_group) ) { - return 0 if not defined $to_position; - return $self->move_to ($to_position); + + # check if someone changed the _grouping_columns - this will + # prevent _is_in_group working, so we need to restore the + # original stashed values + for ($self->_grouping_columns) { + if ($self->is_column_changed ($_)) { + $self->store_column($_, delete $self->{_column_data_in_storage}{$_}); + delete $self->{_dirty_columns}{$_}; + } } - # FIXME this needs to be wrapped in a transaction - { - # Move to end of current group to adjust siblings - $self->move_last; + if ($self->_is_in_group ($to_group) ) { + my $ret; + if (defined $to_position) { + $ret = $self->move_to ($to_position); + } + + return $ret||0; + } - $self->set_inflated_columns({ %$to_group, $position_column => undef }); - my $new_group_count = $self->_group_rs->count; + my $guard = $self->result_source->schema->txn_scope_guard; - if ( not defined($to_position) or $to_position > $new_group_count) { - $self->set_column( - $position_column => $new_group_count - ? $self->_next_position_value ( $self->last_sibling->get_column ($position_column) ) # FIXME - no need to inflate last_sibling - : $self->_initial_position_value - ); - } - else { - my $bumped_pos_val = $self->_position_value ($to_position); - my @between = ($to_position, $new_group_count); - $self->_shift_siblings (1, @between); #shift right - $self->set_column( $position_column => $bumped_pos_val ); - } + # Move to end of current group to adjust siblings + $self->move_last; - $self->_ordered_internal_update; + $self->set_inflated_columns({ %$to_group, $position_column => undef }); + my $new_group_last_posval = $self->_last_sibling_posval; + my $new_group_last_position = $self->_position_from_value ( + $new_group_last_posval + ); - return 1; + if ( not defined($to_position) or $to_position > $new_group_last_position) { + $self->set_column( + $position_column => $new_group_last_position + ? $self->_next_position_value ( $new_group_last_posval ) + : $self->_initial_position_value + ); + } + else { + my $bumped_pos_val = $self->_position_value ($to_position); + my @between = map { $self->_position_value ($_) } ($to_position, $new_group_last_position); + $self->_shift_siblings (1, @between); #shift right + $self->set_column( $position_column => $bumped_pos_val ); } + + $self->_ordered_internal_update; + + $guard->commit; + + return 1; } =head2 insert -Overrides the DBIC insert() method by providing a default -position number. The default will be the number of rows in +Overrides the DBIC insert() method by providing a default +position number. The default will be the number of rows in the table +1, thus positioning the new record at the last position. =cut @@ -453,10 +500,10 @@ sub insert { my $position_column = $self->position_column; unless ($self->get_column($position_column)) { - my $lsib = $self->last_sibling; # FIXME - no need to inflate last_sibling + my $lsib_posval = $self->_last_sibling_posval; $self->set_column( - $position_column => ($lsib - ? $self->_next_position_value ( $lsib->get_column ($position_column) ) + $position_column => (defined $lsib_posval + ? $self->_next_position_value ( $lsib_posval ) : $self->_initial_position_value ) ); @@ -476,59 +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 $upd = shift; - $self->set_inflated_columns($upd) if $upd; - my %changes = $self->get_dirty_columns; - $self->discard_changes; - - my $position_column = $self->position_column; - - # if nothing group/position related changed - short circuit - if (not grep { exists $changes{$_} } ($self->_grouping_columns, $position_column) ) { - return $self->next::method( \%changes, @_ ); - } - - # FIXME this needs to be wrapped in a transaction - { - # 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) { - if (exists $changes{$col}) { - $new_group->{$col} = delete $changes{$col}; # don't want to pass this on to next::method - } - } - - $self->move_to_group( - $new_group, - (exists $changes{$position_column} - # The FIXME bit contradicts the documentation: 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) - ? delete $changes{$position_column} # means there was a position change supplied with the update too - : $self->_position # FIXME! - ), - ); - } - elsif (exists $changes{$position_column}) { - $self->move_to(delete $changes{$position_column}); - } + 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}); + } - return $self->next::method( \%changes, @_ ); - } + 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. @@ -536,11 +576,30 @@ integrity of the positions. sub delete { my $self = shift; - # FIXME this needs to be wrapped in a transaction - { - $self->move_last; - return $self->next::method( @_ ); + + my $guard = $self->result_source->schema->txn_scope_guard; + + $self->move_last; + + my @res; + if (not defined wantarray) { + $self->next::method( @_ ); + } + elsif (wantarray) { + @res = $self->next::method( @_ ); } + else { + $res[0] = $self->next::method( @_ ); + } + + $guard->commit; + 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 @@ -550,22 +609,25 @@ You would want to override the methods below if you use sparse if you are working with preexisting non-normalised position data, or if you need to work with materialized path columns. -=head2 _position +=head2 _position_from_value - my $num_pos = $item->_position; + my $num_pos = $item->_position_from_value ( $pos_value ) -Returns the B of the current object, with the -first object being at position 1, its sibling at position 2 and so on. -By default simply returns the value of L. +Returns the B of an object with a B set to C<$pos_value>. By default simply returns C<$pos_value>. =cut -sub _position { - my $self = shift; +sub _position_from_value { + my ($self, $val) = @_; + + return 0 unless defined $val; # #the right way to do this -# return $self->previous_siblings->count + 1; +# return $self -> _group_rs +# -> search({ $self->position_column => { '<=', $val } }) +# -> count - return $self->get_column ($self->position_column); + return $val; } =head2 _position_value @@ -626,11 +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. @@ -657,13 +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 - - if (grep { $_ eq $position_column } ( map { @$_ } (values %{{ $self->result_source->unique_constraints }} ) ) ) { - - my $rs = $shift_rs->search ({}, { order_by => { "-$ord", $position_column } } ); - # FIXME - no need to inflate each row - while (my $r = $rs->next) { - $r->_ordered_internal_update ({ $position_column => \ "$position_column $op 1" } ); + # 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; + + # 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_data = $cursor->all; + while (my $data = shift @all_data) { + my $pos = shift @$data; + my $cond; + for my $i (0.. $#pcols) { + $cond->{$pcols[$i]} = $data->[$i]; + } + + $rs->find($cond)->update ({ $position_column => $pos + ( ($op eq '+') ? 1 : -1 ) }); } } else { @@ -673,7 +758,7 @@ sub _shift_siblings { =head1 PRIVATE METHODS -These methods are used internally. You should never have the +These methods are used internally. You should never have the need to use them. =head2 _group_rs @@ -696,16 +781,33 @@ 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 + + my $num_pos = $item->_position; + +Returns the B of the current object, with the +first object being at position 1, its sibling at position 2 and so on. + +=cut +sub _position { + my $self = shift; + return $self->_position_from_value ($self->get_column ($self->position_column) ); } =head2 _grouping_clause This method returns one or more name=>value pairs for limiting a search -by the grouping column(s). If the grouping column is not -defined then this will return an empty list. +by the grouping column(s). If the grouping column is not defined then +this will return an empty list. =cut sub _grouping_clause { @@ -762,20 +864,20 @@ This is a short-circuited method, that is used internally by this 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 ambiguos -pogitioning data (i.e. duplicate position value within the same group, +Some day you might get confronted by datasets that have ambiguous +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 data before +you normally would, as it will get confused by the wrong data before having a chance to update the ill-defined row. If you really know what -you are doing use this method which bypases any hooks introduced by +you are doing use this method which bypasses any hooks introduced by this module. =cut 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 (@_); } @@ -785,9 +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 @@ -798,17 +914,17 @@ will prevent such race conditions going undetected. =head2 Multiple Moves -Be careful when issueing 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 +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 -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 +There are times when you will want to move objects as groups, such +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 in the current object's result set to have the new position value. =head2 Default Values @@ -818,7 +934,11 @@ could result in the position not being assigned correctly. =head1 AUTHOR -Aran Deltac + Original code framework + Aran Deltac + + Constraints support and code generalisation + Peter Rabbitson =head1 LICENSE