use strict;
use warnings;
-use base qw/DBIx::Class/;
-
use DBIx::Class::ResultSet;
use DBIx::Class::ResultSourceHandle;
use DBIx::Class::Exception;
use DBIx::Class::Carp;
-use DBIx::Class::GlobalDestruction;
+use Devel::GlobalDestruction;
use Try::Tiny;
use List::Util 'first';
use Scalar::Util qw/blessed weaken isweak/;
use namespace::clean;
+use base qw/DBIx::Class/;
+
__PACKAGE__->mk_group_accessors(simple => qw/
source_name name source_info
_ordered_columns _columns _primaries _unique_constraints
# prefixed relative to the current source, in accordance with where they appear
# in the supplied relationships.
sub _resolve_prefetch {
- my ($self, $pre, $alias, $alias_map, $order, $pref_path) = @_;
+ my ($self, $pre, $alias, $alias_map, $order, $collapse, $pref_path) = @_;
$pref_path ||= [];
if (not defined $pre or not length $pre) {
}
elsif( ref $pre eq 'ARRAY' ) {
return
- map { $self->_resolve_prefetch( $_, $alias, $alias_map, $order, [ @$pref_path ] ) }
+ map { $self->_resolve_prefetch( $_, $alias, $alias_map, $order, $collapse, [ @$pref_path ] ) }
@$pre;
}
elsif( ref $pre eq 'HASH' ) {
my @ret =
map {
- $self->_resolve_prefetch($_, $alias, $alias_map, $order, [ @$pref_path ] ),
+ $self->_resolve_prefetch($_, $alias, $alias_map, $order, $collapse, [ @$pref_path ] ),
$self->related_source($_)->_resolve_prefetch(
- $pre->{$_}, "${alias}.$_", $alias_map, $order, [ @$pref_path, $_] )
+ $pre->{$_}, "${alias}.$_", $alias_map, $order, $collapse, [ @$pref_path, $_] )
} keys %$pre;
return @ret;
}
unless ref($rel_info->{cond}) eq 'HASH';
my $dots = @{[$as_prefix =~ m/\./g]} + 1; # +1 to match the ".${as_prefix}"
+ if (my ($fail) = grep { @{[$_ =~ m/\./g]} == $dots }
+ keys %{$collapse}) {
+ my ($last) = ($fail =~ /([^\.]+)$/);
+ carp (
+ "Prefetching multiple has_many rels ${last} and ${pre} "
+ .(length($as_prefix)
+ ? "at the same level (${as_prefix}) "
+ : "at top level "
+ )
+ . 'will explode the number of row objects retrievable via ->next or ->all. '
+ . 'Use at your own risk.'
+ );
+ }
+
#my @col = map { (/^self\.(.+)$/ ? ("${as_prefix}.$1") : ()); }
# values %{$rel_info->{cond}};
+ $collapse->{".${as_prefix}${pre}"} = [ $rel_source->_pri_cols ];
+ # action at a distance. prepending the '.' allows simpler code
+ # in ResultSet->_collapse_result
my @key = map { (/^foreign\.(.+)$/ ? ($1) : ()); }
keys %{$rel_info->{cond}};
-
push @$order, map { "${as}.$_" } @key;
if (my $rel_order = $rel_info->{attrs}{order_by}) {
}
}
-# Takes a selection list and generates a collapse-map representing
-# row-object fold-points. Every relationship is assigned a set of unique,
-# non-nullable columns (which may *not even be* from the same resultset)
-# and the collapser will use this information to correctly distinguish
-# data of individual to-be-row-objects.
-sub _resolve_collapse {
- my ($self, $as, $as_fq_idx, $rel_chain, $parent_info) = @_;
-
- # for comprehensible error messages put ourselves at the head of the relationship chain
- $rel_chain ||= [ $self->source_name ];
-
- # record top-level fully-qualified column index
- $as_fq_idx ||= { %$as };
-
- my ($my_cols, $rel_cols);
- for (keys %$as) {
- if ($_ =~ /^ ([^\.]+) \. (.+) /x) {
- $rel_cols->{$1}{$2} = 1;
- }
- else {
- $my_cols->{$_} = {}; # important for ||= below
- }
- }
-
- my $relinfo;
- # run through relationships, collect metadata, inject non-left fk-bridges from
- # *INNER-JOINED* children (if any)
- for my $rel (keys %$rel_cols) {
- my $rel_src = $self->related_source ($rel);
- my $inf = $self->relationship_info ($rel);
-
- $relinfo->{$rel}{is_single} = $inf->{attrs}{accessor} && $inf->{attrs}{accessor} ne 'multi';
- $relinfo->{$rel}{is_inner} = ( $inf->{attrs}{join_type} || '' ) !~ /^left/i;
- $relinfo->{$rel}{rsrc} = $rel_src;
-
- my $cond = $inf->{cond};
-
- if (
- ref $cond eq 'HASH'
- and
- keys %$cond
- and
- ! List::Util::first { $_ !~ /^foreign\./ } (keys %$cond)
- and
- ! List::Util::first { $_ !~ /^self\./ } (values %$cond)
- ) {
- for my $f (keys %$cond) {
- my $s = $cond->{$f};
- $_ =~ s/^ (?: foreign | self ) \.//x for ($f, $s);
- $relinfo->{$rel}{fk_map}{$s} = $f;
-
- $my_cols->{$s} ||= { via_fk => "$rel.$f" } # need to know source from *our* pov
- if ($relinfo->{$rel}{is_inner} && defined $rel_cols->{$rel}{$f}); # only if it is inner and in fact selected of course
- }
- }
- }
-
- # if the parent is already defined, assume all of its related FKs are selected
- # (even if they in fact are NOT in the select list). Keep a record of what we
- # assumed, and if any such phantom-column becomes part of our own collapser,
- # throw everything assumed-from-parent away and replace with the collapser of
- # the parent (whatever it may be)
- my $assumed_from_parent;
- unless ($parent_info->{underdefined}) {
- $assumed_from_parent->{columns} = { map
- # only add to the list if we do not already select said columns
- { ! exists $my_cols->{$_} ? ( $_ => 1 ) : () }
- values %{$parent_info->{rel_condition} || {}}
- };
-
- $my_cols->{$_} = { via_collapse => $parent_info->{collapse_on} }
- for keys %{$assumed_from_parent->{columns}};
- }
-
- # get colinfo for everything
- if ($my_cols) {
- $my_cols->{$_}{colinfo} = (
- $self->has_column ($_) ? $self->column_info ($_) : undef
- ) for keys %$my_cols;
- }
-
- my $collapse_map;
-
- # try to resolve based on our columns (plus already inserted FK bridges)
- if (
- $my_cols
- and
- my $uset = $self->_unique_column_set ($my_cols)
- ) {
- # see if the resulting collapser relies on any implied columns,
- # and fix stuff up if this is the case
-
- my $parent_collapser_used;
-
- if (List::Util::first
- { exists $assumed_from_parent->{columns}{$_} }
- keys %$uset
- ) {
- # remove implied stuff from the uset, we will inject the equivalent collapser a bit below
- delete @{$uset}{keys %{$assumed_from_parent->{columns}}};
- $parent_collapser_used = 1;
- }
-
- $collapse_map->{-collapse_on} = {
- %{ $parent_collapser_used ? $parent_info->{collapse_on} : {} },
- (map
- {
- my $fqc = join ('.',
- @{$rel_chain}[1 .. $#$rel_chain],
- ( $my_cols->{$_}{via_fk} || $_ ),
- );
-
- $fqc => $as_fq_idx->{$fqc};
- }
- keys %$uset
- ),
- };
- }
-
- # don't know how to collapse - keep descending down 1:1 chains - if
- # a related non-LEFT 1:1 is resolvable - its condition will collapse us
- # too
- unless ($collapse_map->{-collapse_on}) {
- my @candidates;
-
- for my $rel (keys %$relinfo) {
- next unless ($relinfo->{$rel}{is_single} && $relinfo->{$rel}{is_inner});
-
- if ( my $rel_collapse = $relinfo->{$rel}{rsrc}->_resolve_collapse (
- $rel_cols->{$rel},
- $as_fq_idx,
- [ @$rel_chain, $rel ],
- { underdefined => 1 }
- )) {
- push @candidates, $rel_collapse->{-collapse_on};
- }
- }
-
- # get the set with least amount of columns
- # FIXME - maybe need to implement a data type order as well (i.e. prefer several ints
- # to a single varchar)
- if (@candidates) {
- ($collapse_map->{-collapse_on}) = sort { keys %$a <=> keys %$b } (@candidates);
- }
- }
-
- # Still dont know how to collapse - see if the parent passed us anything
- # (i.e. reuse collapser over 1:1)
- unless ($collapse_map->{-collapse_on}) {
- $collapse_map->{-collapse_on} = $parent_info->{collapse_on}
- if $parent_info->{collapser_reusable};
- }
-
-
- # stop descending into children if we were called by a parent for first-pass
- # and don't despair if nothing was found (there may be other parallel branches
- # to dive into)
- if ($parent_info->{underdefined}) {
- return $collapse_map->{-collapse_on} ? $collapse_map : undef
- }
- # nothing down the chain resolved - can't calculate a collapse-map
- elsif (! $collapse_map->{-collapse_on}) {
- $self->throw_exception ( sprintf
- "Unable to calculate a definitive collapse column set for %s%s: fetch more unique non-nullable columns",
- $self->source_name,
- @$rel_chain > 1
- ? sprintf (' (last member of the %s chain)', join ' -> ', @$rel_chain )
- : ''
- ,
- );
- }
-
-
- # If we got that far - we are collapsable - GREAT! Now go down all children
- # a second time, and fill in the rest
-
- for my $rel (keys %$relinfo) {
-
- $collapse_map->{$rel} = $relinfo->{$rel}{rsrc}->_resolve_collapse (
- { map { $_ => 1 } ( keys %{$rel_cols->{$rel}} ) },
-
- $as_fq_idx,
-
- [ @$rel_chain, $rel],
-
- {
- collapse_on => { %{$collapse_map->{-collapse_on}} },
-
- rel_condition => $relinfo->{$rel}{fk_map},
-
- # if this is a 1:1 our own collapser can be used as a collapse-map
- # (regardless of left or not)
- collapser_reusable => $relinfo->{$rel}{is_single},
- },
- );
- }
-
- return $collapse_map;
-}
-
-sub _unique_column_set {
- my ($self, $cols) = @_;
-
- my %unique = $self->unique_constraints;
-
- # always prefer the PK first, and then shortest constraints first
- USET:
- for my $set (delete $unique{primary}, sort { @$a <=> @$b } (values %unique) ) {
- next unless $set && @$set;
-
- for (@$set) {
- next USET unless ($cols->{$_} && $cols->{$_}{colinfo} && !$cols->{$_}{colinfo}{is_nullable} );
- }
-
- return { map { $_ => 1 } @$set };
- }
-
- return undef;
-}
-
-# Takes an arrayref of {as} dbic column aliases and the collapse and select
-# attributes from the same $rs (the slector requirement is a temporary
-# workaround), and returns a coderef capable of:
-# my $me_pref_clps = $coderef->([$rs->cursor->next])
-# Where the $me_pref_clps arrayref is the future argument to
-# ::ResultSet::_collapse_result.
-#
-# $me_pref_clps->[0] is always returned (even if as an empty hash with no
-# rowdata), however branches of related data in $me_pref_clps->[1] may be
-# pruned short of what was originally requested based on {as}, depending
-# on:
-#
-# * If collapse is requested, a definitive collapse map is calculated for
-# every relationship "fold-point", consisting of a set of values (which
-# may not even be contained in the future 'me' of said relationship
-# (for example a cd.artist_id defines the related inner-joined artist)).
-# Thus a definedness check is carried on all collapse-condition values
-# and if at least one is undef it is assumed that we are dealing with a
-# NULLed right-side of a left-join, so we don't return a related data
-# container at all, which implies no related objects
-#
-# * If we are not collapsing, there is no constraint on having a selector
-# uniquely identifying all possible objects, and the user might have very
-# well requested a column that just *happens* to be all NULLs. What we do
-# in this case is fallback to the old behavior (which is a potential FIXME)
-# by always returning a data container, but only filling it with columns
-# IFF at least one of them is defined. This way we do not get an object
-# with a bunch of has_column_loaded to undef, but at the same time do not
-# further relationships based off this "null" object (e.g. in case the user
-# deliberately skipped link-table values). I am pretty sure there are some
-# tests that codify this behavior, need to find the exact testname.
-#
-# For an example of this coderef in action (and to see its guts) look at
-# t/prefetch/_internals.t
-#
-# This is a huge performance win, as we call the same code for
-# every row returned from the db, thus avoiding repeated method
-# lookups when traversing relationships
-#
-# Also since the coderef is completely stateless (the returned structure is
-# always fresh on every new invocation) this is a very good opportunity for
-# memoization if further speed improvements are needed
-#
-# The way we construct this coderef is somewhat fugly, although I am not
-# sure if the string eval is *that* bad of an idea. The alternative is to
-# have a *very* large number of anon coderefs calling each other in a twisty
-# maze, whereas the current result is a nice, smooth, single-pass function.
-# In any case - the output of this thing is meticulously micro-tested, so
-# any sort of rewrite should be relatively easy
-#
-sub _mk_row_parser {
- my ($self, $as, $with_collapse, $select) = @_;
-
- my $as_indexed = { map
- { $as->[$_] => $_ }
- ( 0 .. $#$as )
- };
-
- # calculate collapse fold-points if needed
- my $collapse_on = do {
- # FIXME
- # only consider real columns (not functions) during collapse resolution
- # this check shouldn't really be here, as fucktards are not supposed to
- # alias random crap to existing column names anyway, but still - just in
- # case (also saves us from select/as mismatches which need fixing as well...)
-
- my $plain_as = { %$as_indexed };
- for (keys %$plain_as) {
- delete $plain_as->{$_} if ref $select->[$plain_as->{$_}];
- }
- $self->_resolve_collapse ($plain_as);
-
- } if $with_collapse;
-
- my $perl = $self->__visit_as ($as_indexed, $collapse_on);
- my $cref = eval "sub { $perl }"
- or die "Oops! _mk_row_parser generated invalid perl:\n$@\n\n$perl\n";
- return $cref;
-}
-
-{
- my $visit_as_dumper; # keep our own DD object around so we don't have to fitz with quoting
-
- sub __visit_as {
- my ($self, $as, $collapse_on, $known_defined) = @_;
- $known_defined ||= {};
-
- # prepopulate the known defined map with our own collapse value positions
- # the rationale is that if an Artist needs column 0 to be uniquely
- # identified, and related CDs need columns 0 and 1, by the time we get to
- # CDs we already know that column 0 is defined (otherwise there would be
- # no related CDs as there is no Artist in the 1st place). So we use this
- # index to cut on repetitive defined() checks.
- $known_defined->{$_}++ for ( values %{$collapse_on->{-collapse_on} || {}} );
-
- my $my_cols = {};
- my $rel_cols;
- for (keys %$as) {
- if ($_ =~ /^ ([^\.]+) \. (.+) /x) {
- $rel_cols->{$1}{$2} = $as->{$_};
- }
- else {
- $my_cols->{$_} = $as->{$_};
- }
- }
-
- my @relperl;
- for my $rel (sort keys %$rel_cols) {
- my $rel_node = $self->__visit_as($rel_cols->{$rel}, $collapse_on->{$rel}, {%$known_defined} );
-
- my @null_checks;
- if ($collapse_on->{$rel}{-collapse_on}) {
- @null_checks = map
- { "(! defined '__VALPOS__${_}__')" }
- ( grep
- { ! $known_defined->{$_} }
- ( sort
- { $a <=> $b }
- values %{$collapse_on->{$rel}{-collapse_on}}
- )
- )
- ;
- }
-
- if (@null_checks) {
- push @relperl, sprintf ( '(%s) ? () : ( %s => %s )',
- join (' || ', @null_checks ),
- $rel,
- $rel_node,
- );
- }
- else {
- push @relperl, "$rel => $rel_node";
- }
- }
- my $rels = @relperl
- ? sprintf ('{ %s }', join (',', @relperl))
- : 'undef'
- ;
-
- my $me = {
- map { $_ => "__VALPOS__$my_cols->{$_}__" } (keys %$my_cols)
- };
-
- my $clps = undef; # funny thing, but this prevents a memory leak, I guess it's Data::Dumper#s fault (mo)
- $clps = [
- map { "__VALPOS__${_}__" } ( sort { $a <=> $b } (values %{$collapse_on->{-collapse_on}}) )
- ] if $collapse_on->{-collapse_on};
-
- # we actually will be producing functional perl code here,
- # thus no second-guessing of what these globals might have
- # been set to. DO NOT CHANGE!
- $visit_as_dumper ||= do {
- require Data::Dumper;
- Data::Dumper->new([])
- ->Purity (1)
- ->Pad ('')
- ->Useqq (0)
- ->Terse (1)
- ->Quotekeys (1)
- ->Deepcopy (1)
- ->Deparse (0)
- ->Maxdepth (0)
- ->Indent (0)
- };
- for ($me, $clps) {
- $_ = $visit_as_dumper->Values ([$_])->Dump;
- }
-
- unless ($collapse_on->{-collapse_on}) { # we are not collapsing, insert a definedness check on 'me'
- $me = sprintf ( '(%s) ? %s : {}',
- join (' || ', map { "( defined '__VALPOS__${_}__')" } (sort { $a <=> $b } values %$my_cols) ),
- $me,
- );
- }
-
- my @rv_list = ($me, $rels, $clps);
- pop @rv_list while ($rv_list[-1] eq 'undef'); # strip trailing undefs
-
- # change the quoted placeholders to unquoted alias-references
- $_ =~ s/ \' __VALPOS__(\d+)__ \' /sprintf ('$_[0][%d]', $1)/gex
- for grep { defined $_ } @rv_list;
- return sprintf '[%s]', join (',', @rv_list);
- }
-}
-
=head2 related_source
=over 4
should not be used. It will be removed before 1.0.
-=head1 AUTHORS
+=head1 AUTHOR AND CONTRIBUTORS
-Matt S. Trout <mst@shadowcatsystems.co.uk>
+See L<AUTHOR|DBIx::Class/AUTHOR> and L<CONTRIBUTORS|DBIx::Class/CONTRIBUTORS> in DBIx::Class
=head1 LICENSE
projects / dbsrgits/DBIx-Class.git / blobdiff