package DBIx::Class::ResultClass::HashRefInflator;
-# $me is the hashref of cols/data from the immediate resultsource
-# $rest is a deep hashref of all the data from the prefetched
-# related sources.
+use strict;
+use warnings;
-sub mk_hash {
- my ($me, $rest) = @_;
+=head1 NAME
- # to avoid emtpy has_many rels contain one empty hashref
- return if (not keys %$me);
+DBIx::Class::ResultClass::HashRefInflator - Get raw hashrefs from a resultset
- return { %$me,
- map { ($_ => ref($rest->{$_}[0]) eq 'ARRAY' ? [ map { mk_hash(@$_) } @{$rest->{$_}} ] : mk_hash(@{$rest->{$_}}) ) } keys %$rest
- };
-}
+=head1 SYNOPSIS
-sub inflate_result {
- my ($self, $source, $me, $prefetch) = @_;
+ use DBIx::Class::ResultClass::HashRefInflator;
+
+ my $rs = $schema->resultset('CD');
+ $rs->result_class('DBIx::Class::ResultClass::HashRefInflator');
+ while (my $hashref = $rs->next) {
+ ...
+ }
+
+=head1 DESCRIPTION
+
+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 row 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 applying this class to a resultset:
+
+=over
+
+=item *
+
+Specify C<< $rs->result_class >> on a specific resultset to affect only that
+resultset (and any chained off of it); or
+
+=item *
+
+Specify C<< __PACKAGE__->result_class >> on your source object to force all
+uses of that result source to be inflated to hash-refs - this approach is not
+recommended.
+
+=back
+
+=cut
+
+##############
+# NOTE
+#
+# Generally people use this to gain as much speed as possible. If a new &mk_hash is
+# implemented, it should be benchmarked using the maint/benchmark_hashrefinflator.pl
+# script (in addition to passing all tests of course :). Additional instructions are
+# provided in the script itself.
+#
+
+# This coderef is a simple recursive function
+# Arguments: ($me, $prefetch) from inflate_result() below
+my $mk_hash;
+$mk_hash = sub {
+ if (ref $_[0] eq 'ARRAY') { # multi relationship
+ return [ map { $mk_hash->(@$_) || () } (@_) ];
+ }
+ else {
+ 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
+ { $_ => $mk_hash->( @{$_[1]->{$_}} ) }
+ ( $_[1] ? (keys %{$_[1]}) : () )
+ };
+
+ # if there is at least one defined column consider the resultset 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
+ for (values %$hash) {
+ if (ref $_ eq 'ARRAY') {
+ return $hash if @$_;
+ }
+ elsif (defined $_) {
+ return $hash;
+ }
+ }
+
+ return undef;
+ }
+};
- return mk_hash($me, $prefetch);
+=head1 METHODS
+
+=head2 inflate_result
+
+Inflates the result and prefetched data into a hash-ref (invoked by L<DBIx::Class::ResultSet>)
+
+=cut
+
+##################################################################################
+# inflate_result is invoked as:
+# HRI->inflate_result ($resultsource_instance, $main_data_hashref, $prefetch_data_hashref)
+sub inflate_result {
+ return $mk_hash->($_[2], $_[3]);
}
+
+=head1 CAVEATS
+
+=over
+
+=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;
projects / dbsrgits/DBIx-Class.git / blobdiff