X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDBIx%2FClass%2FOrdered.pm;h=539abd83390c52bda00d6a8a0d5dea523bee408f;hb=b5ce6748f58040ca877fd05e8f004b14d46b2ba9;hp=2502e933b9552f10b049757a8fc1163657bc6ced;hpb=867f1b28c4934e62ad3545c8607b2bf4c145b34a;p=dbsrgits%2FDBIx-Class.git diff --git a/lib/DBIx/Class/Ordered.pm b/lib/DBIx/Class/Ordered.pm index 2502e93..539abd8 100644 --- a/lib/DBIx/Class/Ordered.pm +++ b/lib/DBIx/Class/Ordered.pm @@ -20,7 +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 ( @@ -40,12 +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; @@ -89,13 +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 @@ -104,7 +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 @@ -115,8 +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 @@ -218,7 +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 @@ -259,7 +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 @@ -275,7 +275,7 @@ sub last_sibling { return defined $lsib ? $lsib : 0; } -# an optimized method to get the last sibling position value without inflating a row object +# an optimized method to get the last sibling position value without inflating a result object sub _last_sibling_posval { my $self = shift; my $position_column = $self->position_column; @@ -367,7 +367,30 @@ sub move_to { my $position_column = $self->position_column; - if ($self->is_column_changed ($position_column) ) { + my $is_txn; + if ($is_txn = $self->result_source->schema->storage->transaction_depth) { + # Reload position state from storage + # The thinking here is that if we are in a transaction, it is + # *more likely* the object went out of sync due to resultset + # level shenanigans. Instead of always reloading (slow) - go + # ahead and hand-hold only in the case of higher layers + # requesting the safety of a txn + + $self->store_column( + $position_column, + ( $self->result_source + ->resultset + ->search($self->_storage_ident_condition, { rows => 1, columns => $position_column }) + ->cursor + ->next + )[0] || $self->throw_exception( + sprintf "Unable to locate object '%s' in storage - object went ouf of sync...?", + $self->ID + ), + ); + delete $self->{_dirty_columns}{$position_column}; + } + elsif ($self->is_column_changed ($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}); @@ -380,7 +403,7 @@ sub move_to { return 0; } - my $guard = $self->result_source->schema->txn_scope_guard; + my $guard = $is_txn ? undef : $self->result_source->schema->txn_scope_guard; my ($direction, @between); if ( $from_position < $to_position ) { @@ -402,7 +425,7 @@ sub move_to { $self->_shift_siblings ($direction, @between); $self->_ordered_internal_update({ $position_column => $new_pos_val }); - $guard->commit; + $guard->commit if $guard; return 1; } @@ -415,7 +438,7 @@ 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. @@ -489,8 +512,8 @@ sub move_to_group { =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 @@ -526,7 +549,7 @@ sub update { my $self = shift; # this is set by _ordered_internal_update() - return $self->next::method(@_) if $self->{_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; @@ -581,19 +604,11 @@ sub delete { $self->move_last; - my @res; - if (not defined wantarray) { - $self->next::method( @_ ); - } - elsif (wantarray) { - @res = $self->next::method( @_ ); - } - else { - $res[0] = $self->next::method( @_ ); - } + $self->next::method( @_ ); $guard->commit; - return wantarray ? @res : $res[0]; + + return $self; } # add the current position/group to the things we track old values for @@ -715,27 +730,25 @@ sub _shift_siblings { my $shift_rs = $self->_group_rs-> search ({ $position_column => { -between => \@between } }); - # some databases (sqlite) are dumb and can not do a blanket - # 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 - + # some databases (sqlite, pg, perhaps others) are dumb and can not do a + # blanket increment/decrement without violating a unique constraint. + # 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. 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; - my $rs = $self->result_source->resultset; - - my @all_pks = $cursor->all; - while (my $pks = shift @all_pks) { - my $cond; - for my $i (0.. $#pcols) { - $cond->{$pcols[$i]} = $pks->[$i]; - } - - $rs->search($cond)->update ({ $position_column => \ "$position_column $op 1" } ); + # 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; + if ( + first { $_ eq $position_column } ( map { @$_ } (values %{{ $rsrc->unique_constraints }} ) ) + ) { + my $clean_rs = $rsrc->resultset; + + for ( $shift_rs->search ( + {}, { order_by => { "-$ord", $position_column }, select => [$position_column, @pcols] } + )->cursor->all ) { + my $pos = shift @$_; + $clean_rs->find(@$_)->update ({ $position_column => $pos + ( ($op eq '+') ? 1 : -1 ) }); } } else { @@ -743,28 +756,16 @@ sub _shift_siblings { } } -=head1 PRIVATE METHODS - -These methods are used internally. You should never have the -need to use them. - -=head2 _group_rs -This method returns a resultset containing all members of the row -group (including the row itself). - -=cut +# This method returns a resultset containing all members of the row +# group (including the row itself). sub _group_rs { my $self = shift; return $self->result_source->resultset->search({$self->_grouping_clause()}); } -=head2 _siblings - -Returns an unordered resultset of all objects in the same group -excluding the object you called this method on. - -=cut +# Returns an unordered resultset of all objects in the same group +# excluding the object you called this method on. sub _siblings { my $self = shift; my $position_column = $self->position_column; @@ -777,38 +778,24 @@ sub _siblings { ; } -=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 +# Returns the B of the current object, with the +# first object being at position 1, its sibling at position 2 and so on. 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. - -=cut +# 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. sub _grouping_clause { my( $self ) = @_; return map { $_ => $self->get_column($_) } $self->_grouping_columns(); } -=head2 _get_grouping_columns - -Returns a list of the column names used for grouping, regardless of whether -they were specified as an arrayref or a single string, and returns () -if there is no grouping. - -=cut +# Returns a list of the column names used for grouping, regardless of whether +# they were specified as an arrayref or a single string, and returns () +# if there is no grouping. sub _grouping_columns { my( $self ) = @_; my $col = $self->grouping_column(); @@ -821,13 +808,7 @@ sub _grouping_columns { } } -=head2 _is_in_group - - $item->_is_in_group( {user => 'fred', list => 'work'} ) - -Returns true if the object is in the group represented by hashref $other - -=cut +# Returns true if the object is in the group represented by hashref $other sub _is_in_group { my ($self, $other) = @_; my $current = {$self->_grouping_clause}; @@ -845,26 +826,21 @@ sub _is_in_group { return 1; } -=head2 _ordered_internal_update - -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 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 wrong data before -having a chance to update the ill-defined row. If you really know what -you are doing use this method which bypasses any hooks introduced by -this module. - -=cut - +# 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 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 wrong data before +# having a chance to update the ill-defined row. If you really know what +# you are doing use this method which bypasses any hooks introduced by +# 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 (@_); } @@ -901,18 +877,18 @@ will prevent such race conditions going undetected. =head2 Multiple Moves -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 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. +If you have multiple same-group result objects already loaded from storage, +you need to be careful when executing C operations on them: +without a L reload the L of the +"siblings" will be out of sync with the underlying storage. + +Starting from version C<0.082800> DBIC will implicitly perform such +reloads when the C happens as a part of a transaction +(a good example of such situation is C<< $ordered_resultset->delete_all >>). + +If it is not possible for you to wrap the entire call-chain in a transaction, +you will need to call L to get an object +up-to-date before proceeding, otherwise undefined behavior will result. =head2 Default Values