X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDBIx%2FClass%2FOrdered.pm;h=35ceba4d905783f141f264648166c212cc1b4bb6;hb=88262f96056323dd426285bd45fbe385168cd0d3;hp=ba5514d20ed0c379ea8829f327839f99f9413010;hpb=a733c37fdebe9bb9ef6e56003e986717e23383d1;p=dbsrgits%2FDBIx-Class-Historic.git

diff --git a/lib/DBIx/Class/Ordered.pm b/lib/DBIx/Class/Ordered.pm
index ba5514d..35ceba4 100644
--- a/lib/DBIx/Class/Ordered.pm
+++ b/lib/DBIx/Class/Ordered.pm
@@ -19,7 +19,7 @@ Create a table for your ordered data.
   );
   # Optional: 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 ... ));
@@ -31,7 +31,7 @@ each row.
   __PACKAGE__->position_column('position');
   __PACKAGE__->grouping_column('group_id'); # optional
 
-Thats it, now you can change the position of your objects.
+That's it, now you can change the position of your objects.
 
   #!/use/bin/perl
   use My::Item;
@@ -73,7 +73,7 @@ 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 
-positional value of each record.  Default to "position".
+positional value of each record.  Defaults to "position".
 
 =cut
 
@@ -83,7 +83,7 @@ __PACKAGE__->mk_classdata( 'position_column' => 'position' );
 
   __PACKAGE__->grouping_column('group_id');
 
-This method specified a column to limit all queries in 
+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.
 
@@ -96,7 +96,7 @@ __PACKAGE__->mk_classdata( 'grouping_column' );
   my $rs = $item->siblings();
   my @siblings = $item->siblings();
 
-Returns either a result set or an array of all other objects 
+Returns either a resultset or an array of all other objects 
 excluding the one you called it on.
 
 =cut
@@ -120,7 +120,7 @@ sub siblings {
   my $sibling = $item->first_sibling();
 
 Returns the first sibling object, or 0 if the first sibling 
-is this sibliing.
+is this sibling.
 
 =cut
 
@@ -139,7 +139,7 @@ sub first_sibling {
 
   my $sibling = $item->last_sibling();
 
-Return 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
@@ -160,8 +160,8 @@ sub last_sibling {
 
   my $sibling = $item->previous_sibling();
 
-Returns the sibling that resides one position back.  Undef 
-is returned if the current object is the first one.
+Returns the sibling that resides one position back.  Returns undef 
+if the current object is the first one.
 
 =cut
 
@@ -182,8 +182,8 @@ sub previous_sibling {
 
   my $sibling = $item->next_sibling();
 
-Returns the sibling that resides one position foward.  Undef 
-is returned if the current object is the last one.
+Returns the sibling that resides one position forward. Returns undef 
+if the current object is the last one.
 
 =cut
 
@@ -205,9 +205,9 @@ sub next_sibling {
 
   $item->move_previous();
 
-Swaps position with the sibling on position previous in the list.  
-1 is returned on success, and 0 is returned if the objects is already 
-the first one.
+Swaps position with the sibling in the position previous in
+the list.  Returns 1 on success, and 0 if the object is
+already the first one.
 
 =cut
 
@@ -221,8 +221,9 @@ sub move_previous {
 
   $item->move_next();
 
-Swaps position with the sibling in the next position.  1 is returned on 
-success, and 0 is returned if the object is already the last in the list.
+Swaps position with the sibling in the next position in the
+list.  Returns 1 on success, and 0 if the object is already
+the last in the list.
 
 =cut
 
@@ -238,8 +239,8 @@ sub move_next {
 
   $item->move_first();
 
-Moves the object to the first position.  1 is returned on 
-success, and 0 is returned if the object is already the first.
+Moves the object to the first position in the list.  Returns 1
+on success, and 0 if the object is already the first.
 
 =cut
 
@@ -252,8 +253,8 @@ sub move_first {
 
   $item->move_last();
 
-Moves the object to the very last position.  1 is returned on 
-success, and 0 is returned if the object is already the last one.
+Moves the object to the last position in the list.  Returns 1
+on success, and 0 if the object is already the last one.
 
 =cut
 
@@ -267,9 +268,9 @@ sub move_last {
 
   $item->move_to( $position );
 
-Moves the object to the specified position.  1 is returned on 
-success, and 0 is returned if the object is already at the 
-specified position.
+Moves the object to the specified position.  Returns 1 on
+success, and 0 if the object is already at the specified
+position.
 
 =cut
 
@@ -279,19 +280,18 @@ sub move_to {
     my $from_position = $self->get_column( $position_column );
     return 0 if ( $to_position < 1 );
     return 0 if ( $from_position==$to_position );
+    my @between = (
+        ( $from_position < $to_position )
+        ? ( $from_position+1, $to_position )
+        : ( $to_position, $from_position-1 )
+    );
     my $rs = $self->result_source->resultset->search({
-        -and => [
-            $position_column => { ($from_position>$to_position?'<':'>') => $from_position },
-            $position_column => { ($from_position>$to_position?'>=':'<=') => $to_position },
-        ],
+        $position_column => { -between => [ @between ] },
         $self->_grouping_clause(),
     });
     my $op = ($from_position>$to_position) ? '+' : '-';
-    $rs->update({
-        $position_column => \"$position_column $op 1",
-    });
-    $self->set_column( $position_column => $to_position );
-    $self->update();
+    $rs->update({ $position_column => \"$position_column $op 1" });
+    $self->update({ $position_column => $to_position });
     return 1;
 }
 
@@ -332,7 +332,7 @@ need to use them.
 
 =head2 _grouping_clause
 
-This method returns a name=>value pare for limiting a search 
+This method returns a name=>value pair for limiting a search 
 by the collection column.  If the collection column is not 
 defined then this will return an empty list.
 
@@ -352,11 +352,20 @@ __END__
 
 =head1 BUGS
 
+=head2 Unique Constraints
+
+Unique indexes and constraints on the position column are not 
+supported at this time.  It would be make sense to support them, 
+but there are some unexpected database issues that make this 
+hard to do.  The main problem from the author's view is that 
+SQLite (the DB engine that we use for testing) does not support 
+ORDER BY on updates.
+
 =head2 Race Condition on Insert
 
 If a position is not specified for an insert than a position 
 will be chosen based on COUNT(*)+1.  But, it first selects the 
-count then inserts the record.  The space of time between select 
+count, and then inserts the record.  The space of time between select 
 and insert introduces a race condition.  To fix this we need the 
 ability to lock tables in DBIC.  I've added an entry in the TODO 
 about this.
@@ -368,7 +377,7 @@ 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.
 
-The are times when you will want to move objects as groups, such 
+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