X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDBIx%2FClass%2FFilterColumn.pm;h=feef4f1610d0fd1e6619432a5e9c174e4abb8daa;hb=fcf32d045;hp=9ae5007913d3906e542c5fbaafd295eec1e8d9dd;hpb=9b2c0de65a57ab32a0a18293ad49fa30f70fee31;p=dbsrgits%2FDBIx-Class.git

diff --git a/lib/DBIx/Class/FilterColumn.pm b/lib/DBIx/Class/FilterColumn.pm
index 9ae5007..feef4f1 100644
--- a/lib/DBIx/Class/FilterColumn.pm
+++ b/lib/DBIx/Class/FilterColumn.pm
@@ -7,14 +7,23 @@ use base qw/DBIx::Class::Row/;
 sub filter_column {
   my ($self, $col, $attrs) = @_;
 
+  my $colinfo = $self->column_info($col);
+
+  $self->throw_exception('FilterColumn does not work with InflateColumn')
+    if $self->isa('DBIx::Class::InflateColumn') &&
+      defined $colinfo->{_inflate_info};
+
   $self->throw_exception("No such column $col to filter")
     unless $self->has_column($col);
 
-  $self->throw_exception("filter_column needs attr hashref")
+  $self->throw_exception('filter_column expects a hashref of filter specifications')
     unless ref $attrs eq 'HASH';
 
-  $self->column_info($col)->{_filter_info} = $attrs;
-  my $acc = $self->column_info($col)->{accessor};
+  $self->throw_exception('An invocation of filter_column() must specify either a filter_from_storage or filter_to_storage')
+    unless $attrs->{filter_from_storage} || $attrs->{filter_to_storage};
+
+  $colinfo->{_filter_info} = $attrs;
+  my $acc = $colinfo->{accessor};
   $self->mk_group_accessors(filtered_column => [ (defined $acc ? $acc : $col), $col]);
   return 1;
 }
@@ -30,9 +39,8 @@ sub _column_from_storage {
   return $value unless exists $info->{_filter_info};
 
   my $filter = $info->{_filter_info}{filter_from_storage};
-  $self->throw_exception("No inflator for $col") unless defined $filter;
 
-  return $self->$filter($value);
+  return defined $filter ? $self->$filter($value) : $value;
 }
 
 sub _column_to_storage {
@@ -44,8 +52,8 @@ sub _column_to_storage {
   return $value unless exists $info->{_filter_info};
 
   my $unfilter = $info->{_filter_info}{filter_to_storage};
-  $self->throw_exception("No unfilter for $col") unless defined $unfilter;
-  return $self->$unfilter($value);
+
+  return defined $unfilter ? $self->$unfilter($value) : $value;
 }
 
 sub get_filtered_column {
@@ -62,26 +70,71 @@ sub get_filtered_column {
   return $self->{_filtered_column}{$col} = $self->_column_from_storage($col, $val);
 }
 
+sub get_column {
+  my ($self, $col) = @_;
+  if (exists $self->{_filtered_column}{$col}) {
+    return $self->{_column_data}{$col} ||= $self->_column_to_storage ($col, $self->{_filtered_column}{$col});
+  }
+
+  return $self->next::method ($col);
+}
+
+# sadly a separate codepath in Row.pm ( used by insert() )
+sub get_columns {
+  my $self = shift;
+
+  foreach my $col (keys %{$self->{_filtered_column}||{}}) {
+    $self->{_column_data}{$col} ||= $self->_column_to_storage ($col, $self->{_filtered_column}{$col})
+      if exists $self->{_filtered_column}{$col};
+  }
+
+  $self->next::method (@_);
+}
+
+sub store_column {
+  my ($self, $col) = (shift, @_);
+
+  # blow cache
+  delete $self->{_filtered_column}{$col};
+
+  $self->next::method(@_);
+}
+
 sub set_filtered_column {
   my ($self, $col, $filtered) = @_;
 
-  $self->set_column($col, $self->_column_to_storage($col, $filtered));
+  # do not blow up the cache via set_column unless necessary
+  # (filtering may be expensive!)
+  if (exists $self->{_filtered_column}{$col}) {
+    return $filtered
+      if ($self->_eq_column_values ($col, $filtered, $self->{_filtered_column}{$col} ) );
 
-  delete $self->{_filtered_column}{$col};
+    $self->make_column_dirty ($col); # so the comparison won't run again
+  }
 
-  return $filtered;
+  $self->set_column($col, $self->_column_to_storage($col, $filtered));
+
+  return $self->{_filtered_column}{$col} = $filtered;
 }
 
 sub update {
   my ($self, $attrs, @rest) = @_;
+
   foreach my $key (keys %{$attrs||{}}) {
-    if ($self->has_column($key) &&
-          exists $self->column_info($key)->{_filter_info}) {
-      my $val = delete $attrs->{$key};
-      $self->set_filtered_column($key, $val);
-      $attrs->{$key} = $self->_column_to_storage($key, $val)
+    if (
+      $self->has_column($key)
+        &&
+      exists $self->column_info($key)->{_filter_info}
+    ) {
+      $self->set_filtered_column($key, delete $attrs->{$key});
+
+      # FIXME update() reaches directly into the object-hash
+      # and we may *not* have a filtered value there - thus
+      # the void-ctx filter-trigger
+      $self->get_column($key) unless exists $self->{_column_data}{$key};
     }
   }
+
   return $self->next::method($attrs, @rest);
 }
 
@@ -94,10 +147,10 @@ sub new {
   foreach my $key (keys %{$attrs||{}}) {
     if ($obj->has_column($key) &&
           exists $obj->column_info($key)->{_filter_info} ) {
-      my $val = delete $attrs->{$key};
-      $obj->set_filtered_column($key, $val);
+      $obj->set_filtered_column($key, $attrs->{$key});
     }
   }
+
   return $obj;
 }
 
@@ -109,7 +162,12 @@ DBIx::Class::FilterColumn - Automatically convert column data
 
 =head1 SYNOPSIS
 
- # In your result classes
+In your Schema or DB class add "FilterColumn" to the top of the component list.
+
+  __PACKAGE__->load_components(qw( FilterColumn ... ));
+
+Set up filters for the columns you want to convert.
+
  __PACKAGE__->filter_column( money => {
      filter_to_storage => 'to_pennies',
      filter_from_storage => 'from_pennies',
@@ -121,6 +179,7 @@ DBIx::Class::FilterColumn - Automatically convert column data
 
  1;
 
+
 =head1 DESCRIPTION
 
 This component is meant to be a more powerful, but less DWIM-y,
@@ -133,15 +192,23 @@ be done with L<DBIx::Class::InflateColumn> can be done with this component.
 =head2 filter_column
 
  __PACKAGE__->filter_column( colname => {
-     filter_from_storage => 'method',
-     filter_to_storage   => 'method',
+     filter_from_storage => 'method'|\&coderef,
+     filter_to_storage   => 'method'|\&coderef,
  })
 
-This is the method that you need to call to set up a filtered column.  It takes
-exactly two arguments; the first being the column name the second being a
-C<HashRef> with C<filter_from_storage> and C<filter_to_storage> having
-something that can be called as a method.  The method will be called with
-the value of the column as the first non-C<$self> argument.
+This is the method that you need to call to set up a filtered column. It takes
+exactly two arguments; the first being the column name the second being a hash
+reference with C<filter_from_storage> and C<filter_to_storage> set to either
+a method name or a code reference. In either case the filter is invoked as:
+
+  $row_obj->$filter_specification ($value_to_filter)
+
+with C<$filter_specification> being chosen depending on whether the
+C<$value_to_filter> is being retrieved from or written to permanent
+storage.
+
+If a specific directional filter is not specified, the original value will be
+passed to/from storage unfiltered.
 
 =head2 get_filtered_column
 
@@ -155,10 +222,21 @@ Returns the filtered value of the column
 
 Sets the filtered value of the column
 
-=head2 update
+=head1 EXAMPLE OF USE
+
+Some databases have restrictions on values that can be passed to
+boolean columns, and problems can be caused by passing value that
+perl considers to be false (such as C<undef>).
 
-Just overridden to filter changed columns through this component
+One solution to this is to ensure that the boolean values are set
+to something that the database can handle - such as numeric zero
+and one, using code like this:-
 
-=head2 new
+    __PACKAGE__->filter_column(
+        my_boolean_column => {
+            filter_to_storage   => sub { $_[1] ? 1 : 0 },
+        }
+    );
 
-Just overridden to filter columns through this component
+In this case the C<filter_from_storage> is not required, as just
+passing the database value through to perl does the right thing.