use strict;
use warnings;
+use base qw/DBIx::Class/;
+
use DBIx::Class::ResultSet;
use DBIx::Class::ResultSourceHandle;
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, $collapse, $pref_path) = @_;
+ my ($self, $pre, $alias, $alias_map, $order, $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, $collapse, [ @$pref_path ] ) }
+ map { $self->_resolve_prefetch( $_, $alias, $alias_map, $order, [ @$pref_path ] ) }
@$pre;
}
elsif( ref $pre eq 'HASH' ) {
my @ret =
map {
- $self->_resolve_prefetch($_, $alias, $alias_map, $order, $collapse, [ @$pref_path ] ),
+ $self->_resolve_prefetch($_, $alias, $alias_map, $order, [ @$pref_path ] ),
$self->related_source($_)->_resolve_prefetch(
- $pre->{$_}, "${alias}.$_", $alias_map, $order, $collapse, [ @$pref_path, $_] )
+ $pre->{$_}, "${alias}.$_", $alias_map, $order, [ @$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
projects / dbsrgits/DBIx-Class.git / blobdiff