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}} )
105 if (! $args->{collapse} ) {
106 $src = assemble_simple_parser({
107 val_index => $val_index,
108 hri_style => $args->{hri_style},
109 prune_null_branches => $args->{prune_null_branches},
113 my $collapse_map = $self->_resolve_collapse ({
114 premultiplied => $args->{premultiplied},
116 # only consider real columns (not functions) during collapse resolution
117 # this check shouldn't really be here, as fucktards are not supposed to
118 # alias random crap to existing column names anyway, but still - just in
120 # FIXME !!!! - this does not yet deal with unbalanced selectors correctly
121 # (it is now trivial as the attrs specify where things go out of sync
124 { ref $args->{selection}[$val_index->{$_}] ? () : ( $_ => $val_index->{$_} ) }
129 $src = assemble_collapsing_parser({
130 val_index => $val_index,
131 collapse_map => $collapse_map,
132 hri_style => $args->{hri_style},
133 prune_null_branches => $args->{prune_null_branches},
137 return (! $args->{eval})
139 : eval "sub { $src }" || die $@
144 # Takes an arrayref selection list and generates a collapse-map representing
145 # row-object fold-points. Every relationship is assigned a set of unique,
146 # non-nullable columns (which may *not even be* from the same resultset)
147 # and the collapser will use this information to correctly distinguish
148 # data of individual to-be-row-objects. See t/resultset/rowparser_internals.t
149 # for extensive RV examples
150 sub _resolve_collapse {
151 my ($self, $args, $common_args) = @_;
153 # for comprehensible error messages put ourselves at the head of the relationship chain
154 $args->{_rel_chain} ||= [ $self->source_name ];
156 # record top-level fully-qualified column index, signify toplevelness
157 unless ($common_args->{_as_fq_idx}) {
158 $common_args->{_as_fq_idx} = { %{$args->{as}} };
159 $args->{_is_top_level} = 1;
162 my ($my_cols, $rel_cols);
163 for (keys %{$args->{as}}) {
164 if ($_ =~ /^ ([^\.]+) \. (.+) /x) {
165 $rel_cols->{$1}{$2} = 1;
168 $my_cols->{$_} = {}; # important for ||='s below
173 # run through relationships, collect metadata
174 for my $rel (keys %$rel_cols) {
175 my $inf = $self->relationship_info ($rel);
178 is_single => ( $inf->{attrs}{accessor} && $inf->{attrs}{accessor} ne 'multi' ),
179 is_inner => ( ( $inf->{attrs}{join_type} || '' ) !~ /^left/i),
180 rsrc => $self->related_source($rel),
183 # FIME - need to use _resolve_cond here instead
184 my $cond = $inf->{cond};
191 ! defined first { $_ !~ /^foreign\./ } (keys %$cond)
193 ! defined first { $_ !~ /^self\./ } (values %$cond)
195 for my $f (keys %$cond) {
197 $_ =~ s/^ (?: foreign | self ) \.//x for ($f, $s);
198 $relinfo->{$rel}{fk_map}{$s} = $f;
203 # inject non-left fk-bridges from *INNER-JOINED* children (if any)
204 for my $rel (grep { $relinfo->{$_}{is_inner} } keys %$relinfo) {
205 my $ri = $relinfo->{$rel};
206 for (keys %{$ri->{fk_map}} ) {
207 # need to know source from *our* pov, hence $rel.col
208 $my_cols->{$_} ||= { via_fk => "$rel.$ri->{fk_map}{$_}" }
209 if defined $rel_cols->{$rel}{$ri->{fk_map}{$_}} # in fact selected
213 # if the parent is already defined *AND* we have an inner reverse relationship
214 # (i.e. do not exist without it) , assume all of its related FKs are selected
215 # (even if they in fact are NOT in the select list). Keep a record of what we
216 # assumed, and if any such phantom-column becomes part of our own collapser,
217 # throw everything assumed-from-parent away and replace with the collapser of
218 # the parent (whatever it may be)
219 my $assumed_from_parent;
220 if ( ! $args->{_parent_info}{underdefined} and ! $args->{_parent_info}{rev_rel_is_optional} ) {
221 for my $col ( values %{$args->{_parent_info}{rel_condition} || {}} ) {
222 next if exists $my_cols->{$col};
223 $my_cols->{$col} = { via_collapse => $args->{_parent_info}{collapse_on_idcols} };
224 $assumed_from_parent->{columns}{$col}++;
228 # get colinfo for everything
230 my $ci = $self->columns_info;
231 $my_cols->{$_}{colinfo} = $ci->{$_} for keys %$my_cols;
236 # first try to reuse the parent's collapser (i.e. reuse collapser over 1:1)
237 # (makes for a leaner coderef later)
238 unless ($collapse_map->{-identifying_columns}) {
239 $collapse_map->{-identifying_columns} = $args->{_parent_info}{collapse_on_idcols}
240 if $args->{_parent_info}{collapser_reusable};
243 # Still dont know how to collapse - try to resolve based on our columns (plus already inserted FK bridges)
245 ! $collapse_map->{-identifying_columns}
249 my $idset = $self->_identifying_column_set ({map { $_ => $my_cols->{$_}{colinfo} } keys %$my_cols})
251 # see if the resulting collapser relies on any implied columns,
252 # and fix stuff up if this is the case
253 my @reduced_set = grep { ! $assumed_from_parent->{columns}{$_} } @$idset;
255 $collapse_map->{-identifying_columns} = [ __unique_numlist(
256 @{ $args->{_parent_info}{collapse_on_idcols}||[] },
261 @{$args->{_rel_chain}}[1 .. $#{$args->{_rel_chain}}],
262 ( $my_cols->{$_}{via_fk} || $_ ),
265 $common_args->{_as_fq_idx}->{$fqc};
272 # Stil don't know how to collapse - keep descending down 1:1 chains - if
273 # a related non-LEFT 1:1 is resolvable - its condition will collapse us
275 unless ($collapse_map->{-identifying_columns}) {
278 for my $rel (keys %$relinfo) {
279 next unless ($relinfo->{$rel}{is_single} && $relinfo->{$rel}{is_inner});
281 if ( my $rel_collapse = $relinfo->{$rel}{rsrc}->_resolve_collapse ({
282 as => $rel_cols->{$rel},
283 _rel_chain => [ @{$args->{_rel_chain}}, $rel ],
284 _parent_info => { underdefined => 1 },
286 push @candidates, $rel_collapse->{-identifying_columns};
290 # get the set with least amount of columns
291 # FIXME - maybe need to implement a data type order as well (i.e. prefer several ints
292 # to a single varchar)
294 ($collapse_map->{-identifying_columns}) = sort { scalar @$a <=> scalar @$b } (@candidates);
298 # Stil don't know how to collapse, and we are the root node. Last ditch
299 # effort in case we are *NOT* premultiplied.
300 # Run through *each multi* all the way down, left or not, and all
301 # *left* singles (a single may become a multi underneath) . When everything
302 # gets back see if all the rels link to us definitively. If this is the
303 # case we are good - either one of them will define us, or if all are NULLs
304 # we know we are "unique" due to the "non-premultiplied" check
306 ! $collapse_map->{-identifying_columns}
308 ! $args->{premultiplied}
310 $args->{_is_top_level}
312 my (@collapse_sets, $uncollapsible_chain);
314 for my $rel (keys %$relinfo) {
316 # we already looked at these higher up
317 next if ($relinfo->{$rel}{is_single} && $relinfo->{$rel}{is_inner});
319 if (my $clps = $relinfo->{$rel}{rsrc}->_resolve_collapse ({
320 as => $rel_cols->{$rel},
321 _rel_chain => [ @{$args->{_rel_chain}}, $rel ],
322 _parent_info => { underdefined => 1 },
325 # for singles use the idcols wholesale (either there or not)
326 if ($relinfo->{$rel}{is_single}) {
327 push @collapse_sets, $clps->{-identifying_columns};
329 elsif (! $relinfo->{$rel}{fk_map}) {
330 $uncollapsible_chain = 1;
334 my $defined_cols_parent_side;
336 for my $fq_col ( grep { /^$rel\.[^\.]+$/ } keys %{$args->{as}} ) {
337 my ($col) = $fq_col =~ /([^\.]+)$/;
339 $defined_cols_parent_side->{$_} = $args->{as}{$fq_col} for grep
340 { $relinfo->{$rel}{fk_map}{$_} eq $col }
341 keys %{$relinfo->{$rel}{fk_map}}
345 if (my $set = $self->_identifying_column_set([ keys %$defined_cols_parent_side ]) ) {
346 push @collapse_sets, [ sort map { $defined_cols_parent_side->{$_} } @$set ];
349 $uncollapsible_chain = 1;
355 $uncollapsible_chain = 1;
360 unless ($uncollapsible_chain) {
361 # if we got here - we are good to go, but the construction is tricky
362 # since our children will want to include our collapse criteria - we
363 # don't give them anything (safe, since they are all collapsible on their own)
364 # in addition we record the individual collapse posibilities
365 # of all left children node collapsers, and merge them in the rowparser
367 $collapse_map->{-identifying_columns} = [];
368 $collapse_map->{-identifying_columns_variants} = [ sort {
369 (scalar @$a) <=> (scalar @$b) or max(@$a) <=> max(@$b)
374 # stop descending into children if we were called by a parent for first-pass
375 # and don't despair if nothing was found (there may be other parallel branches
377 if ($args->{_parent_info}{underdefined}) {
378 return $collapse_map->{-identifying_columns} ? $collapse_map : undef
380 # nothing down the chain resolved - can't calculate a collapse-map
381 elsif (! $collapse_map->{-identifying_columns}) {
382 $self->throw_exception ( sprintf
383 "Unable to calculate a definitive collapse column set for %s%s: fetch more unique non-nullable columns",
385 @{$args->{_rel_chain}} > 1
386 ? sprintf (' (last member of the %s chain)', join ' -> ', @{$args->{_rel_chain}} )
392 # If we got that far - we are collapsable - GREAT! Now go down all children
393 # a second time, and fill in the rest
395 $collapse_map->{-identifying_columns} = [ __unique_numlist(
396 @{ $args->{_parent_info}{collapse_on_idcols}||[] },
397 @{ $collapse_map->{-identifying_columns} },
401 for my $rel (sort keys %$relinfo) {
403 $collapse_map->{$rel} = $relinfo->{$rel}{rsrc}->_resolve_collapse ({
404 as => { map { $_ => 1 } ( keys %{$rel_cols->{$rel}} ) },
405 _rel_chain => [ @{$args->{_rel_chain}}, $rel],
408 collapse_on_idcols => [ @{$collapse_map->{-identifying_columns}} ],
410 rel_condition => $relinfo->{$rel}{fk_map},
412 is_optional => ! $relinfo->{$rel}{is_inner},
414 # if there is at least one *inner* reverse relationship which is HASH-based (equality only)
415 # we can safely assume that the child can not exist without us
416 rev_rel_is_optional => ( first
417 { ref $_->{cond} eq 'HASH' and ($_->{attrs}{join_type}||'') !~ /^left/i }
418 values %{ $self->reverse_relationship_info($rel) },
421 # if this is a 1:1 our own collapser can be used as a collapse-map
422 # (regardless of left or not)
423 collapser_reusable => (
424 $relinfo->{$rel}{is_single}
426 $relinfo->{$rel}{is_inner}
428 @{$collapse_map->{-identifying_columns}}
433 $collapse_map->{$rel}{-is_single} = 1 if $relinfo->{$rel}{is_single};
434 $collapse_map->{$rel}{-is_optional} ||= 1 unless $relinfo->{$rel}{is_inner};
437 return $collapse_map;
440 # adding a dep on MoreUtils *just* for this is retarded
441 sub __unique_numlist {
442 sort { $a <=> $b } keys %{ {map { $_ => 1 } @_ }}