X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDBIx%2FClass%2FResultClass%2FHashRefInflator.pm;h=4223930bf6cf23db39cafcb12bef528ca517c7e1;hb=fb13a49f;hp=4aa362ab0e5b542927f9d978503543fe5b15aa2b;hpb=833045455985bf452c5a4817d238444643b40bc7;p=dbsrgits%2FDBIx-Class.git

diff --git a/lib/DBIx/Class/ResultClass/HashRefInflator.pm b/lib/DBIx/Class/ResultClass/HashRefInflator.pm
index 4aa362a..4223930 100644
--- a/lib/DBIx/Class/ResultClass/HashRefInflator.pm
+++ b/lib/DBIx/Class/ResultClass/HashRefInflator.pm
@@ -5,21 +5,36 @@ use warnings;
 
 =head1 NAME
 
-DBIx::Class::ResultClass::HashRefInflator
+DBIx::Class::ResultClass::HashRefInflator - Get raw hashrefs from a resultset
 
 =head1 SYNOPSIS
 
- my $rs = $schema->resultset('CD');
+ use DBIx::Class::ResultClass::HashRefInflator;
 
+ my $rs = $schema->resultset('CD');
  $rs->result_class('DBIx::Class::ResultClass::HashRefInflator');
+ while (my $hashref = $rs->next) {
+   ...
+ }
+
+  OR as an attribute:
+
+ my $rs = $schema->resultset('CD')->search({}, {
+   result_class => 'DBIx::Class::ResultClass::HashRefInflator',
+ });
+ while (my $hashref = $rs->next) {
+   ...
+ }
 
 =head1 DESCRIPTION
 
-DBIx::Class is not built for speed: it's built for convenience and
-ease of use. But sometimes you just need to get the data, and skip the
-fancy objects. That is what this class provides.
+DBIx::Class is faster than older ORMs like Class::DBI but it still isn't
+designed primarily for speed. Sometimes you need to quickly retrieve the data
+from a massive resultset, while skipping the creation of fancy result objects.
+Specifying this class as a C<result_class> for a resultset will change C<< $rs->next >>
+to return a plain data hash-ref (or a list of such hash-refs if C<< $rs->all >> is used).
 
-There are two ways of using this class.
+There are two ways of applying this class to a resultset:
 
 =over
 
@@ -36,55 +51,97 @@ recommended.
 
 =back
 
+=cut
+
+##############
+# NOTE
+#
+# Generally people use this to gain as much speed as possible. If a new &mk_hash is
+# implemented, it should be benchmarked using the maint/benchmark_hashrefinflator.pl
+# script (in addition to passing all tests of course :)
+
+# This coderef is a simple recursive function
+# Arguments: ($me, $prefetch, $is_root) from inflate_result() below
+my $mk_hash;
+$mk_hash = sub {
+
+  my $hash = {
+    # the main hash could be an undef if we are processing a skipped-over join
+    $_[0] ? %{$_[0]} : (),
+
+    # the second arg is a hash of arrays for each prefetched relation
+    map {
+      ref $_[1]->{$_}[0] eq 'ARRAY' # multi rel or not?
+        ? ( $_ => [ map
+            { $mk_hash->(@$_) || () }
+            @{$_[1]->{$_}}
+        ] )
+        : ( $_ => $mk_hash->( @{$_[1]->{$_}} ) )
+
+    } ( $_[1] ? ( keys %{$_[1]} ) : () )
+  };
+
+  # if there is at least one defined column *OR* we are at the root of
+  # the resultset - consider the result real (and not an emtpy has_many
+  # rel containing one empty hashref)
+  # an empty arrayref is an empty multi-sub-prefetch - don't consider
+  # those either
+  return $hash if $_[2];
+
+  for (values %$hash) {
+    return $hash if (
+      defined $_
+        and
+      (ref $_ ne 'ARRAY' or scalar @$_)
+    );
+  }
+
+  return undef;
+};
+
 =head1 METHODS
 
 =head2 inflate_result
 
-Inflates the result and prefetched data into a hash-ref using L<mk_hash>.
+Inflates the result and prefetched data into a hash-ref (invoked by L<DBIx::Class::ResultSet>)
 
 =cut
 
+##################################################################################
+# inflate_result is invoked as:
+# HRI->inflate_result ($resultsource_instance, $main_data_hashref, $prefetch_data_hashref)
 sub inflate_result {
-    my ($self, $source, $me, $prefetch) = @_;
-
-    return mk_hash($me, $prefetch);
+  return $mk_hash->($_[2], $_[3], 'is_root');
 }
 
-=head2 mk_hash
 
-This does all the work of inflating the (pre)fetched data.
+=head1 CAVEATS
 
-=cut
+=over
 
-sub mk_hash {
-    my ($me, $rest) = @_;
-
-    # $me is the hashref of cols/data from the immediate resultsource
-    # $rest is a deep hashref of all the data from the prefetched
-    # related sources.
-
-    # to avoid emtpy has_many rels contain one empty hashref
-    return undef if (not keys %$me);
-
-    my $def;
-
-    foreach (values %$me) {
-        if (defined $_) {
-            $def = 1;
-            last;
-        }
-    }
-    return undef unless $def;
-
-    return { %$me,
-        map {
-          ( $_ =>
-             ref($rest->{$_}[0]) eq 'ARRAY'
-                 ? [ grep defined, map mk_hash(@$_), @{$rest->{$_}} ]
-                 : mk_hash( @{$rest->{$_}} )
-          )
-        } keys %$rest
-    };
-}
+=item *
+
+This will not work for relationships that have been prefetched. Consider the
+following:
+
+ my $artist = $artitsts_rs->search({}, {prefetch => 'cds' })->first;
+
+ my $cds = $artist->cds;
+ $cds->result_class('DBIx::Class::ResultClass::HashRefInflator');
+ my $first = $cds->first;
+
+C<$first> will B<not> be a hashref, it will be a normal CD row since
+HashRefInflator only affects resultsets at inflation time, and prefetch causes
+relations to be inflated when the master C<$artist> row is inflated.
+
+=item *
+
+Column value inflation, e.g., using modules like
+L<DBIx::Class::InflateColumn::DateTime>, is not performed.
+The returned hash contains the raw database values.
+
+=back
+
+=cut
 
 1;