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) = @_;
98 die "HRI without pruning makes zero sense"
99 if ( $args->{hri_style} && ! $args->{prune_null_branches} );
102 hri_style => $args->{hri_style},
103 prune_null_branches => $args->{prune_null_branches},
105 { $args->{inflate_map}[$_] => $_ }
106 ( 0 .. $#{$args->{inflate_map}} )
110 my $src = $args->{collapse}
111 ? assemble_collapsing_parser({
113 collapse_map => $self->_resolve_collapse ({
115 # only consider real columns (not functions) during collapse resolution
116 # this check shouldn't really be here, as fucktards are not supposed to
117 # alias random crap to existing column names anyway, but still - just in
119 # FIXME !!!! - this does not yet deal with unbalanced selectors correctly
120 # (it is now trivial as the attrs specify where things go out of sync
123 { ref $args->{selection}[$common{val_index}{$_}] ? () : ( $_ => $common{val_index}{$_} ) }
124 keys %{$common{val_index}}
126 premultiplied => $args->{premultiplied},
129 : assemble_simple_parser(
135 ? ( eval "sub $src" || die $@ )
141 # Takes an arrayref selection list and generates a collapse-map representing
142 # row-object fold-points. Every relationship is assigned a set of unique,
143 # non-nullable columns (which may *not even be* from the same resultset)
144 # and the collapser will use this information to correctly distinguish
145 # data of individual to-be-row-objects. See t/resultset/rowparser_internals.t
146 # for extensive RV examples
147 sub _resolve_collapse {
148 my ($self, $args, $common_args) = @_;
150 # for comprehensible error messages put ourselves at the head of the relationship chain
151 $args->{_rel_chain} ||= [ $self->source_name ];
153 # record top-level fully-qualified column index, signify toplevelness
154 unless ($common_args->{_as_fq_idx}) {
155 $common_args->{_as_fq_idx} = { %{$args->{as}} };
156 $args->{_is_top_level} = 1;
159 my ($my_cols, $rel_cols);
160 for (keys %{$args->{as}}) {
161 if ($_ =~ /^ ([^\.]+) \. (.+) /x) {
162 $rel_cols->{$1}{$2} = 1;
165 $my_cols->{$_} = {}; # important for ||='s below
170 # run through relationships, collect metadata
171 for my $rel (keys %$rel_cols) {
172 my $inf = $self->relationship_info ($rel);
175 is_single => ( $inf->{attrs}{accessor} && $inf->{attrs}{accessor} ne 'multi' ),
176 is_inner => ( ( $inf->{attrs}{join_type} || '' ) !~ /^left/i),
177 rsrc => $self->related_source($rel),
180 # FIME - need to use _resolve_cond here instead
181 my $cond = $inf->{cond};
188 ! defined first { $_ !~ /^foreign\./ } (keys %$cond)
190 ! defined first { $_ !~ /^self\./ } (values %$cond)
192 for my $f (keys %$cond) {
194 $_ =~ s/^ (?: foreign | self ) \.//x for ($f, $s);
195 $relinfo->{$rel}{fk_map}{$s} = $f;
200 # inject non-left fk-bridges from *INNER-JOINED* children (if any)
201 for my $rel (grep { $relinfo->{$_}{is_inner} } keys %$relinfo) {
202 my $ri = $relinfo->{$rel};
203 for (keys %{$ri->{fk_map}} ) {
204 # need to know source from *our* pov, hence $rel.col
205 $my_cols->{$_} ||= { via_fk => "$rel.$ri->{fk_map}{$_}" }
206 if defined $rel_cols->{$rel}{$ri->{fk_map}{$_}} # in fact selected
210 # if the parent is already defined *AND* we have an inner reverse relationship
211 # (i.e. do not exist without it) , assume all of its related FKs are selected
212 # (even if they in fact are NOT in the select list). Keep a record of what we
213 # assumed, and if any such phantom-column becomes part of our own collapser,
214 # throw everything assumed-from-parent away and replace with the collapser of
215 # the parent (whatever it may be)
216 my $assumed_from_parent;
217 if ( ! $args->{_parent_info}{underdefined} and ! $args->{_parent_info}{rev_rel_is_optional} ) {
218 for my $col ( values %{$args->{_parent_info}{rel_condition} || {}} ) {
219 next if exists $my_cols->{$col};
220 $my_cols->{$col} = { via_collapse => $args->{_parent_info}{collapse_on_idcols} };
221 $assumed_from_parent->{columns}{$col}++;
225 # get colinfo for everything
227 my $ci = $self->columns_info;
228 $my_cols->{$_}{colinfo} = $ci->{$_} for keys %$my_cols;
233 # first try to reuse the parent's collapser (i.e. reuse collapser over 1:1)
234 # (makes for a leaner coderef later)
235 unless ($collapse_map->{-identifying_columns}) {
236 $collapse_map->{-identifying_columns} = $args->{_parent_info}{collapse_on_idcols}
237 if $args->{_parent_info}{collapser_reusable};
240 # Still dont know how to collapse - try to resolve based on our columns (plus already inserted FK bridges)
242 ! $collapse_map->{-identifying_columns}
246 my $idset = $self->_identifying_column_set ({map { $_ => $my_cols->{$_}{colinfo} } keys %$my_cols})
248 # see if the resulting collapser relies on any implied columns,
249 # and fix stuff up if this is the case
250 my @reduced_set = grep { ! $assumed_from_parent->{columns}{$_} } @$idset;
252 $collapse_map->{-identifying_columns} = [ __unique_numlist(
253 @{ $args->{_parent_info}{collapse_on_idcols}||[] },
258 @{$args->{_rel_chain}}[1 .. $#{$args->{_rel_chain}}],
259 ( $my_cols->{$_}{via_fk} || $_ ),
262 $common_args->{_as_fq_idx}->{$fqc};
269 # Stil don't know how to collapse - keep descending down 1:1 chains - if
270 # a related non-LEFT 1:1 is resolvable - its condition will collapse us
272 unless ($collapse_map->{-identifying_columns}) {
275 for my $rel (keys %$relinfo) {
276 next unless ($relinfo->{$rel}{is_single} && $relinfo->{$rel}{is_inner});
278 if ( my $rel_collapse = $relinfo->{$rel}{rsrc}->_resolve_collapse ({
279 as => $rel_cols->{$rel},
280 _rel_chain => [ @{$args->{_rel_chain}}, $rel ],
281 _parent_info => { underdefined => 1 },
283 push @candidates, $rel_collapse->{-identifying_columns};
287 # get the set with least amount of columns
288 # FIXME - maybe need to implement a data type order as well (i.e. prefer several ints
289 # to a single varchar)
291 ($collapse_map->{-identifying_columns}) = sort { scalar @$a <=> scalar @$b } (@candidates);
295 # Stil don't know how to collapse, and we are the root node. Last ditch
296 # effort in case we are *NOT* premultiplied.
297 # Run through *each multi* all the way down, left or not, and all
298 # *left* singles (a single may become a multi underneath) . When everything
299 # gets back see if all the rels link to us definitively. If this is the
300 # case we are good - either one of them will define us, or if all are NULLs
301 # we know we are "unique" due to the "non-premultiplied" check
303 ! $collapse_map->{-identifying_columns}
305 ! $args->{premultiplied}
307 $args->{_is_top_level}
309 my (@collapse_sets, $uncollapsible_chain);
311 for my $rel (keys %$relinfo) {
313 # we already looked at these higher up
314 next if ($relinfo->{$rel}{is_single} && $relinfo->{$rel}{is_inner});
316 if (my $clps = $relinfo->{$rel}{rsrc}->_resolve_collapse ({
317 as => $rel_cols->{$rel},
318 _rel_chain => [ @{$args->{_rel_chain}}, $rel ],
319 _parent_info => { underdefined => 1 },
322 # for singles use the idcols wholesale (either there or not)
323 if ($relinfo->{$rel}{is_single}) {
324 push @collapse_sets, $clps->{-identifying_columns};
326 elsif (! $relinfo->{$rel}{fk_map}) {
327 $uncollapsible_chain = 1;
331 my $defined_cols_parent_side;
333 for my $fq_col ( grep { /^$rel\.[^\.]+$/ } keys %{$args->{as}} ) {
334 my ($col) = $fq_col =~ /([^\.]+)$/;
336 $defined_cols_parent_side->{$_} = $args->{as}{$fq_col} for grep
337 { $relinfo->{$rel}{fk_map}{$_} eq $col }
338 keys %{$relinfo->{$rel}{fk_map}}
342 if (my $set = $self->_identifying_column_set([ keys %$defined_cols_parent_side ]) ) {
343 push @collapse_sets, [ sort map { $defined_cols_parent_side->{$_} } @$set ];
346 $uncollapsible_chain = 1;
352 $uncollapsible_chain = 1;
357 unless ($uncollapsible_chain) {
358 # if we got here - we are good to go, but the construction is tricky
359 # since our children will want to include our collapse criteria - we
360 # don't give them anything (safe, since they are all collapsible on their own)
361 # in addition we record the individual collapse posibilities
362 # of all left children node collapsers, and merge them in the rowparser
364 $collapse_map->{-identifying_columns} = [];
365 $collapse_map->{-identifying_columns_variants} = [ sort {
366 (scalar @$a) <=> (scalar @$b) or max(@$a) <=> max(@$b)
371 # stop descending into children if we were called by a parent for first-pass
372 # and don't despair if nothing was found (there may be other parallel branches
374 if ($args->{_parent_info}{underdefined}) {
375 return $collapse_map->{-identifying_columns} ? $collapse_map : undef
377 # nothing down the chain resolved - can't calculate a collapse-map
378 elsif (! $collapse_map->{-identifying_columns}) {
379 $self->throw_exception ( sprintf
380 "Unable to calculate a definitive collapse column set for %s%s: fetch more unique non-nullable columns",
382 @{$args->{_rel_chain}} > 1
383 ? sprintf (' (last member of the %s chain)', join ' -> ', @{$args->{_rel_chain}} )
389 # If we got that far - we are collapsable - GREAT! Now go down all children
390 # a second time, and fill in the rest
392 $collapse_map->{-identifying_columns} = [ __unique_numlist(
393 @{ $args->{_parent_info}{collapse_on_idcols}||[] },
394 @{ $collapse_map->{-identifying_columns} },
398 for my $rel (sort keys %$relinfo) {
400 $collapse_map->{$rel} = $relinfo->{$rel}{rsrc}->_resolve_collapse ({
401 as => { map { $_ => 1 } ( keys %{$rel_cols->{$rel}} ) },
402 _rel_chain => [ @{$args->{_rel_chain}}, $rel],
405 collapse_on_idcols => [ @{$collapse_map->{-identifying_columns}} ],
407 rel_condition => $relinfo->{$rel}{fk_map},
409 is_optional => ! $relinfo->{$rel}{is_inner},
411 # if there is at least one *inner* reverse relationship which is HASH-based (equality only)
412 # we can safely assume that the child can not exist without us
413 rev_rel_is_optional => ( first
414 { ref $_->{cond} eq 'HASH' and ($_->{attrs}{join_type}||'') !~ /^left/i }
415 values %{ $self->reverse_relationship_info($rel) },
418 # if this is a 1:1 our own collapser can be used as a collapse-map
419 # (regardless of left or not)
420 collapser_reusable => (
421 $relinfo->{$rel}{is_single}
423 $relinfo->{$rel}{is_inner}
425 @{$collapse_map->{-identifying_columns}}
430 $collapse_map->{$rel}{-is_single} = 1 if $relinfo->{$rel}{is_single};
431 $collapse_map->{$rel}{-is_optional} ||= 1 unless $relinfo->{$rel}{is_inner};
434 return $collapse_map;
437 # adding a dep on MoreUtils *just* for this is retarded
438 sub __unique_numlist {
439 sort { $a <=> $b } keys %{ {map { $_ => 1 } @_ }}