1 package # hide from the pauses
2 DBIx::Class::ResultSource::RowParser;
7 use base 'DBIx::Class';
10 use List::Util qw(first max);
13 use DBIx::Class::ResultSource::RowParser::Util qw(
14 assemble_simple_parser
15 assemble_collapsing_parser
20 # Accepts one or more relationships for the current source and returns an
21 # array of column names for each of those relationships. Column names are
22 # prefixed relative to the current source, in accordance with where they appear
23 # in the supplied relationships.
24 sub _resolve_prefetch {
25 my ($self, $pre, $alias, $alias_map, $order, $pref_path) = @_;
28 if (not defined $pre or not length $pre) {
31 elsif( ref $pre eq 'ARRAY' ) {
33 map { $self->_resolve_prefetch( $_, $alias, $alias_map, $order, [ @$pref_path ] ) }
36 elsif( ref $pre eq 'HASH' ) {
39 $self->_resolve_prefetch($_, $alias, $alias_map, $order, [ @$pref_path ] ),
40 $self->related_source($_)->_resolve_prefetch(
41 $pre->{$_}, "${alias}.$_", $alias_map, $order, [ @$pref_path, $_] )
46 $self->throw_exception(
47 "don't know how to resolve prefetch reftype ".ref($pre));
51 $p = $p->{$_} for (@$pref_path, $pre);
53 $self->throw_exception (
54 "Unable to resolve prefetch '$pre' - join alias map does not contain an entry for path: "
55 . join (' -> ', @$pref_path, $pre)
56 ) if (ref $p->{-join_aliases} ne 'ARRAY' or not @{$p->{-join_aliases}} );
58 my $as = shift @{$p->{-join_aliases}};
60 my $rel_info = $self->relationship_info( $pre );
61 $self->throw_exception( $self->source_name . " has no such relationship '$pre'" )
64 my $as_prefix = ($alias =~ /^.*?\.(.+)$/ ? $1.'.' : '');
66 return map { [ "${as}.$_", "${as_prefix}${pre}.$_", ] }
67 $self->related_source($pre)->columns;
71 # Takes an arrayref of {as} dbic column aliases and the collapse and select
72 # attributes from the same $rs (the selector requirement is a temporary
73 # workaround... I hope), and returns a coderef capable of:
74 # my $me_pref_clps = $coderef->([$rs->cursor->next/all])
75 # Where the $me_pref_clps arrayref is the future argument to inflate_result()
77 # For an example of this coderef in action (and to see its guts) look at
78 # t/resultset/rowparser_internals.t
80 # This is a huge performance win, as we call the same code for every row
81 # returned from the db, thus avoiding repeated method lookups when traversing
84 # Also since the coderef is completely stateless (the returned structure is
85 # always fresh on every new invocation) this is a very good opportunity for
86 # memoization if further speed improvements are needed
88 # The way we construct this coderef is somewhat fugly, although the result is
89 # really worth it. The final coderef does not perform any kind of recursion -
90 # the entire nested structure constructor is rolled out into a single scope.
92 # In any case - the output of this thing is meticulously micro-tested, so
93 # any sort of adjustment/rewrite should be relatively easy (fsvo relatively)
96 my ($self, $args) = @_;
99 { $args->{inflate_map}[$_] => $_ }
100 ( 0 .. $#{$args->{inflate_map}} )
103 if (! $args->{collapse} ) {
104 return assemble_simple_parser({
105 val_index => $val_index,
109 my $collapse_map = $self->_resolve_collapse ({
110 premultiplied => $args->{premultiplied},
112 # only consider real columns (not functions) during collapse resolution
113 # this check shouldn't really be here, as fucktards are not supposed to
114 # alias random crap to existing column names anyway, but still - just in
116 # FIXME !!!! - this does not yet deal with unbalanced selectors correctly
117 # (it is now trivial as the attrs specify where things go out of sync
120 { ref $args->{selection}[$val_index->{$_}] ? () : ( $_ => $val_index->{$_} ) }
125 return assemble_collapsing_parser({
126 val_index => $val_index,
127 collapse_map => $collapse_map,
133 # Takes an arrayref selection list and generates a collapse-map representing
134 # row-object fold-points. Every relationship is assigned a set of unique,
135 # non-nullable columns (which may *not even be* from the same resultset)
136 # and the collapser will use this information to correctly distinguish
137 # data of individual to-be-row-objects. See t/resultset/rowparser_internals.t
138 # for extensive RV examples
139 sub _resolve_collapse {
140 my ($self, $args, $common_args) = @_;
142 # for comprehensible error messages put ourselves at the head of the relationship chain
143 $args->{_rel_chain} ||= [ $self->source_name ];
145 # record top-level fully-qualified column index, signify toplevelness
146 unless ($common_args->{_as_fq_idx}) {
147 $common_args->{_as_fq_idx} = { %{$args->{as}} };
148 $args->{_is_top_level} = 1;
151 my ($my_cols, $rel_cols);
152 for (keys %{$args->{as}}) {
153 if ($_ =~ /^ ([^\.]+) \. (.+) /x) {
154 $rel_cols->{$1}{$2} = 1;
157 $my_cols->{$_} = {}; # important for ||='s below
162 # run through relationships, collect metadata
163 for my $rel (keys %$rel_cols) {
164 my $inf = $self->relationship_info ($rel);
167 is_single => ( $inf->{attrs}{accessor} && $inf->{attrs}{accessor} ne 'multi' ),
168 is_inner => ( ( $inf->{attrs}{join_type} || '' ) !~ /^left/i),
169 rsrc => $self->related_source($rel),
172 # FIME - need to use _resolve_cond here instead
173 my $cond = $inf->{cond};
180 ! defined first { $_ !~ /^foreign\./ } (keys %$cond)
182 ! defined first { $_ !~ /^self\./ } (values %$cond)
184 for my $f (keys %$cond) {
186 $_ =~ s/^ (?: foreign | self ) \.//x for ($f, $s);
187 $relinfo->{$rel}{fk_map}{$s} = $f;
192 # inject non-left fk-bridges from *INNER-JOINED* children (if any)
193 for my $rel (grep { $relinfo->{$_}{is_inner} } keys %$relinfo) {
194 my $ri = $relinfo->{$rel};
195 for (keys %{$ri->{fk_map}} ) {
196 # need to know source from *our* pov, hence $rel.col
197 $my_cols->{$_} ||= { via_fk => "$rel.$ri->{fk_map}{$_}" }
198 if defined $rel_cols->{$rel}{$ri->{fk_map}{$_}} # in fact selected
202 # if the parent is already defined, assume all of its related FKs are selected
203 # (even if they in fact are NOT in the select list). Keep a record of what we
204 # assumed, and if any such phantom-column becomes part of our own collapser,
205 # throw everything assumed-from-parent away and replace with the collapser of
206 # the parent (whatever it may be)
207 my $assumed_from_parent;
208 unless ($args->{_parent_info}{underdefined}) {
209 for my $col ( values %{$args->{_parent_info}{rel_condition} || {}} ) {
210 next if exists $my_cols->{$col};
211 $my_cols->{$col} = { via_collapse => $args->{_parent_info}{collapse_on_idcols} };
212 $assumed_from_parent->{columns}{$col}++;
216 # get colinfo for everything
218 my $ci = $self->columns_info;
219 $my_cols->{$_}{colinfo} = $ci->{$_} for keys %$my_cols;
224 # first try to reuse the parent's collapser (i.e. reuse collapser over 1:1)
225 # (makes for a leaner coderef later)
226 unless ($collapse_map->{-identifying_columns}) {
227 $collapse_map->{-identifying_columns} = $args->{_parent_info}{collapse_on_idcols}
228 if $args->{_parent_info}{collapser_reusable};
232 # Still dont know how to collapse - try to resolve based on our columns (plus already inserted FK bridges)
234 ! $collapse_map->{-identifying_columns}
238 my $idset = $self->_identifying_column_set ({map { $_ => $my_cols->{$_}{colinfo} } keys %$my_cols})
240 # see if the resulting collapser relies on any implied columns,
241 # and fix stuff up if this is the case
242 my @reduced_set = grep { ! $assumed_from_parent->{columns}{$_} } @$idset;
244 $collapse_map->{-identifying_columns} = [ __unique_numlist(
245 @{ $args->{_parent_info}{collapse_on_idcols}||[] },
250 @{$args->{_rel_chain}}[1 .. $#{$args->{_rel_chain}}],
251 ( $my_cols->{$_}{via_fk} || $_ ),
254 $common_args->{_as_fq_idx}->{$fqc};
261 # Stil don't know how to collapse - keep descending down 1:1 chains - if
262 # a related non-LEFT 1:1 is resolvable - its condition will collapse us
264 unless ($collapse_map->{-identifying_columns}) {
267 for my $rel (keys %$relinfo) {
268 next unless ($relinfo->{$rel}{is_single} && $relinfo->{$rel}{is_inner});
270 if ( my $rel_collapse = $relinfo->{$rel}{rsrc}->_resolve_collapse ({
271 as => $rel_cols->{$rel},
272 _rel_chain => [ @{$args->{_rel_chain}}, $rel ],
273 _parent_info => { underdefined => 1 },
275 push @candidates, $rel_collapse->{-identifying_columns};
279 # get the set with least amount of columns
280 # FIXME - maybe need to implement a data type order as well (i.e. prefer several ints
281 # to a single varchar)
283 ($collapse_map->{-identifying_columns}) = sort { scalar @$a <=> scalar @$b } (@candidates);
287 # Stil don't know how to collapse, and we are the root node. Last ditch
288 # effort in case we are *NOT* premultiplied.
289 # Run through *each multi* all the way down, left or not, and all
290 # *left* singles (a single may become a multi underneath) . When everything
291 # gets back see if all the rels link to us definitively. If this is the
292 # case we are good - either one of them will define us, or if all are NULLs
293 # we know we are "unique" due to the "non-premultiplied" check
295 ! $collapse_map->{-identifying_columns}
297 ! $args->{premultiplied}
299 $args->{_is_top_level}
301 my (@collapse_sets, $uncollapsible_chain);
303 for my $rel (keys %$relinfo) {
305 # we already looked at these higher up
306 next if ($relinfo->{$rel}{is_single} && $relinfo->{$rel}{is_inner});
308 if (my $clps = $relinfo->{$rel}{rsrc}->_resolve_collapse ({
309 as => $rel_cols->{$rel},
310 _rel_chain => [ @{$args->{_rel_chain}}, $rel ],
311 _parent_info => { underdefined => 1 },
314 # for singles use the idcols wholesale (either there or not)
315 if ($relinfo->{$rel}{is_single}) {
316 push @collapse_sets, $clps->{-identifying_columns};
318 elsif (! $relinfo->{$rel}{fk_map}) {
319 $uncollapsible_chain = 1;
323 my $defined_cols_parent_side;
325 for my $fq_col ( grep { /^$rel\.[^\.]+$/ } keys %{$args->{as}} ) {
326 my ($col) = $fq_col =~ /([^\.]+)$/;
328 $defined_cols_parent_side->{$_} = $args->{as}{$fq_col} for grep
329 { $relinfo->{$rel}{fk_map}{$_} eq $col }
330 keys %{$relinfo->{$rel}{fk_map}}
334 if (my $set = $self->_identifying_column_set([ keys %$defined_cols_parent_side ]) ) {
335 push @collapse_sets, [ sort map { $defined_cols_parent_side->{$_} } @$set ];
338 $uncollapsible_chain = 1;
344 $uncollapsible_chain = 1;
349 unless ($uncollapsible_chain) {
350 # if we got here - we are good to go, but the construction is tricky
351 # since our children will want to include our collapse criteria - we
352 # don't give them anything (safe, since they are all collapsible on their own)
353 # in addition we record the individual collapse posibilities
354 # of all left children node collapsers, and merge them in the rowparser
356 $collapse_map->{-identifying_columns} = [];
357 $collapse_map->{-identifying_columns_variants} = [ sort {
358 (scalar @$a) <=> (scalar @$b) or max(@$a) <=> max(@$b)
363 # stop descending into children if we were called by a parent for first-pass
364 # and don't despair if nothing was found (there may be other parallel branches
366 if ($args->{_parent_info}{underdefined}) {
367 return $collapse_map->{-identifying_columns} ? $collapse_map : undef
369 # nothing down the chain resolved - can't calculate a collapse-map
370 elsif (! $collapse_map->{-identifying_columns}) {
371 $self->throw_exception ( sprintf
372 "Unable to calculate a definitive collapse column set for %s%s: fetch more unique non-nullable columns",
374 @{$args->{_rel_chain}} > 1
375 ? sprintf (' (last member of the %s chain)', join ' -> ', @{$args->{_rel_chain}} )
381 # If we got that far - we are collapsable - GREAT! Now go down all children
382 # a second time, and fill in the rest
384 $collapse_map->{-is_optional} = 1 if $args->{_parent_info}{is_optional};
388 for my $rel (sort keys %$relinfo) {
390 $collapse_map->{$rel} = $relinfo->{$rel}{rsrc}->_resolve_collapse ({
391 as => { map { $_ => 1 } ( keys %{$rel_cols->{$rel}} ) },
392 _rel_chain => [ @{$args->{_rel_chain}}, $rel],
395 collapse_on_idcols => [ @{$collapse_map->{-identifying_columns}} ],
397 rel_condition => $relinfo->{$rel}{fk_map},
399 is_optional => $collapse_map->{-is_optional},
401 # if this is a 1:1 our own collapser can be used as a collapse-map
402 # (regardless of left or not)
403 collapser_reusable => (
404 $relinfo->{$rel}{is_single}
406 $relinfo->{$rel}{is_inner}
408 @{$collapse_map->{-identifying_columns}}
413 $collapse_map->{$rel}{-is_single} = 1 if $relinfo->{$rel}{is_single};
414 $collapse_map->{$rel}{-is_optional} ||= 1 unless $relinfo->{$rel}{is_inner};
417 return $collapse_map;
420 # adding a dep on MoreUtils *just* for this is retarded
421 sub __unique_numlist {
422 sort { $a <=> $b } keys %{ {map { $_ => 1 } @_ }}