1 package # hide from the pauses
2 DBIx::Class::ResultSource::RowParser;
7 use base 'DBIx::Class';
10 use List::Util qw(first max);
12 use Scalar::Util qw(blessed);
14 use DBIx::Class::ResultSource::RowParser::Util qw(
15 assemble_simple_parser
16 assemble_collapsing_parser
21 # Accepts one or more relationships for the current source and returns an
22 # array of column names for each of those relationships. Column names are
23 # prefixed relative to the current source, in accordance with where they appear
24 # in the supplied relationships.
25 sub _resolve_prefetch {
26 my ($self, $pre, $alias, $alias_map, $order, $pref_path) = @_;
29 if (not defined $pre or not length $pre) {
32 elsif( ref $pre eq 'ARRAY' ) {
34 map { $self->_resolve_prefetch( $_, $alias, $alias_map, $order, [ @$pref_path ] ) }
37 elsif( ref $pre eq 'HASH' ) {
40 $self->_resolve_prefetch($_, $alias, $alias_map, $order, [ @$pref_path ] ),
41 $self->related_source($_)->_resolve_prefetch(
42 $pre->{$_}, "${alias}.$_", $alias_map, $order, [ @$pref_path, $_] )
47 $self->throw_exception(
48 "don't know how to resolve prefetch reftype ".ref($pre));
52 $p = $p->{$_} for (@$pref_path, $pre);
54 $self->throw_exception (
55 "Unable to resolve prefetch '$pre' - join alias map does not contain an entry for path: "
56 . join (' -> ', @$pref_path, $pre)
57 ) if (ref $p->{-join_aliases} ne 'ARRAY' or not @{$p->{-join_aliases}} );
59 my $as = shift @{$p->{-join_aliases}};
61 my $rel_info = $self->relationship_info( $pre );
62 $self->throw_exception( $self->source_name . " has no such relationship '$pre'" )
65 my $as_prefix = ($alias =~ /^.*?\.(.+)$/ ? $1.'.' : '');
67 return map { [ "${as}.$_", "${as_prefix}${pre}.$_", ] }
68 $self->related_source($pre)->columns;
72 # Takes an arrayref of {as} dbic column aliases and the collapse and select
73 # attributes from the same $rs (the selector requirement is a temporary
74 # workaround... I hope), and returns a coderef capable of:
75 # my $me_pref_clps = $coderef->([$rs->cursor->next/all])
76 # Where the $me_pref_clps arrayref is the future argument to inflate_result()
78 # For an example of this coderef in action (and to see its guts) look at
79 # t/resultset/rowparser_internals.t
81 # This is a huge performance win, as we call the same code for every row
82 # returned from the db, thus avoiding repeated method lookups when traversing
85 # Also since the coderef is completely stateless (the returned structure is
86 # always fresh on every new invocation) this is a very good opportunity for
87 # memoization if further speed improvements are needed
89 # The way we construct this coderef is somewhat fugly, although the result is
90 # really worth it. The final coderef does not perform any kind of recursion -
91 # the entire nested structure constructor is rolled out into a single scope.
93 # In any case - the output of this thing is meticulously micro-tested, so
94 # any sort of adjustment/rewrite should be relatively easy (fsvo relatively)
97 # $args and $attrs are separated to delineate what is core collapser stuff and
98 # what is dbic $rs specific
99 my ($self, $args, $attrs) = @_;
101 die "HRI without pruning makes zero sense"
102 if ( $args->{hri_style} && ! $args->{prune_null_branches} );
105 hri_style => $args->{hri_style},
106 prune_null_branches => $args->{prune_null_branches},
108 { $args->{inflate_map}[$_] => $_ }
109 ( 0 .. $#{$args->{inflate_map}} )
113 my $check_null_columns;
115 my $src = (! $args->{collapse} ) ? assemble_simple_parser(\%common) : do {
116 my $collapse_map = $self->_resolve_collapse ({
118 # only consider real columns (not functions) during collapse resolution
119 # this check shouldn't really be here, as fucktards are not supposed to
120 # alias random crap to existing column names anyway, but still - just in
122 # FIXME !!!! - this does not yet deal with unbalanced selectors correctly
123 # (it is now trivial as the attrs specify where things go out of sync
126 { ref $attrs->{select}[$common{val_index}{$_}] ? () : ( $_ => $common{val_index}{$_} ) }
127 keys %{$common{val_index}}
129 premultiplied => $args->{premultiplied},
132 $check_null_columns = $collapse_map->{-identifying_columns}
133 if @{$collapse_map->{-identifying_columns}};
135 assemble_collapsing_parser({
137 collapse_map => $collapse_map,
142 $args->{eval} ? ( eval "sub $src" || die $@ ) : $src,
148 # Takes an arrayref selection list and generates a collapse-map representing
149 # row-object fold-points. Every relationship is assigned a set of unique,
150 # non-nullable columns (which may *not even be* from the same resultset)
151 # and the collapser will use this information to correctly distinguish
152 # data of individual to-be-row-objects. See t/resultset/rowparser_internals.t
153 # for extensive RV examples
154 sub _resolve_collapse {
155 my ($self, $args, $common_args) = @_;
157 # for comprehensible error messages put ourselves at the head of the relationship chain
158 $args->{_rel_chain} ||= [ $self->source_name ];
160 # record top-level fully-qualified column index, signify toplevelness
161 unless ($common_args->{_as_fq_idx}) {
162 $common_args->{_as_fq_idx} = { %{$args->{as}} };
163 $args->{_is_top_level} = 1;
166 my ($my_cols, $rel_cols);
167 for (keys %{$args->{as}}) {
168 if ($_ =~ /^ ([^\.]+) \. (.+) /x) {
169 $rel_cols->{$1}{$2} = 1;
172 $my_cols->{$_} = {}; # important for ||='s below
177 # run through relationships, collect metadata
178 for my $rel (keys %$rel_cols) {
179 my $inf = $self->relationship_info ($rel);
182 is_single => ( $inf->{attrs}{accessor} && $inf->{attrs}{accessor} ne 'multi' ),
183 is_inner => ( ( $inf->{attrs}{join_type} || '' ) !~ /^left/i),
184 rsrc => $self->related_source($rel),
187 # FIME - need to use _resolve_cond here instead
188 my $cond = $inf->{cond};
195 ! defined first { $_ !~ /^foreign\./ } (keys %$cond)
197 ! defined first { $_ !~ /^self\./ } (values %$cond)
199 for my $f (keys %$cond) {
201 $_ =~ s/^ (?: foreign | self ) \.//x for ($f, $s);
202 $relinfo->{$rel}{fk_map}{$s} = $f;
204 } elsif (blessed($cond) and $cond->isa('Data::Query::ExprBuilder')) {
205 my $cols = $self->_join_condition_to_hashref($cond->{expr});
206 @{$relinfo->{$rel}{fk_map}}{values %$cols} = keys %$cols;
210 # inject non-left fk-bridges from *INNER-JOINED* children (if any)
211 for my $rel (grep { $relinfo->{$_}{is_inner} } keys %$relinfo) {
212 my $ri = $relinfo->{$rel};
213 for (keys %{$ri->{fk_map}} ) {
214 # need to know source from *our* pov, hence $rel.col
215 $my_cols->{$_} ||= { via_fk => "$rel.$ri->{fk_map}{$_}" }
216 if defined $rel_cols->{$rel}{$ri->{fk_map}{$_}} # in fact selected
220 # if the parent is already defined *AND* we have an inner reverse relationship
221 # (i.e. do not exist without it) , assume all of its related FKs are selected
222 # (even if they in fact are NOT in the select list). Keep a record of what we
223 # assumed, and if any such phantom-column becomes part of our own collapser,
224 # throw everything assumed-from-parent away and replace with the collapser of
225 # the parent (whatever it may be)
226 my $assumed_from_parent;
227 if ( ! $args->{_parent_info}{underdefined} and ! $args->{_parent_info}{rev_rel_is_optional} ) {
228 for my $col ( values %{$args->{_parent_info}{rel_condition} || {}} ) {
229 next if exists $my_cols->{$col};
230 $my_cols->{$col} = { via_collapse => $args->{_parent_info}{collapse_on_idcols} };
231 $assumed_from_parent->{columns}{$col}++;
235 # get colinfo for everything
237 my $ci = $self->columns_info;
238 $my_cols->{$_}{colinfo} = $ci->{$_} for keys %$my_cols;
243 # first try to reuse the parent's collapser (i.e. reuse collapser over 1:1)
244 # (makes for a leaner coderef later)
245 unless ($collapse_map->{-identifying_columns}) {
246 $collapse_map->{-identifying_columns} = $args->{_parent_info}{collapse_on_idcols}
247 if $args->{_parent_info}{collapser_reusable};
250 # Still don't know how to collapse - try to resolve based on our columns (plus already inserted FK bridges)
252 ! $collapse_map->{-identifying_columns}
256 my $idset = $self->_identifying_column_set ({map { $_ => $my_cols->{$_}{colinfo} } keys %$my_cols})
258 # see if the resulting collapser relies on any implied columns,
259 # and fix stuff up if this is the case
260 my @reduced_set = grep { ! $assumed_from_parent->{columns}{$_} } @$idset;
262 $collapse_map->{-identifying_columns} = [ __unique_numlist(
263 @{ $args->{_parent_info}{collapse_on_idcols}||[] },
268 @{$args->{_rel_chain}}[1 .. $#{$args->{_rel_chain}}],
269 ( $my_cols->{$_}{via_fk} || $_ ),
272 $common_args->{_as_fq_idx}->{$fqc};
279 # Stil don't know how to collapse - keep descending down 1:1 chains - if
280 # a related non-LEFT 1:1 is resolvable - its condition will collapse us
282 unless ($collapse_map->{-identifying_columns}) {
285 for my $rel (keys %$relinfo) {
286 next unless ($relinfo->{$rel}{is_single} && $relinfo->{$rel}{is_inner});
288 if ( my $rel_collapse = $relinfo->{$rel}{rsrc}->_resolve_collapse ({
289 as => $rel_cols->{$rel},
290 _rel_chain => [ @{$args->{_rel_chain}}, $rel ],
291 _parent_info => { underdefined => 1 },
293 push @candidates, $rel_collapse->{-identifying_columns};
297 # get the set with least amount of columns
298 # FIXME - maybe need to implement a data type order as well (i.e. prefer several ints
299 # to a single varchar)
301 ($collapse_map->{-identifying_columns}) = sort { scalar @$a <=> scalar @$b } (@candidates);
305 # Stil don't know how to collapse, and we are the root node. Last ditch
306 # effort in case we are *NOT* premultiplied.
307 # Run through *each multi* all the way down, left or not, and all
308 # *left* singles (a single may become a multi underneath) . When everything
309 # gets back see if all the rels link to us definitively. If this is the
310 # case we are good - either one of them will define us, or if all are NULLs
311 # we know we are "unique" due to the "non-premultiplied" check
313 ! $collapse_map->{-identifying_columns}
315 ! $args->{premultiplied}
317 $args->{_is_top_level}
319 my (@collapse_sets, $uncollapsible_chain);
321 for my $rel (keys %$relinfo) {
323 # we already looked at these higher up
324 next if ($relinfo->{$rel}{is_single} && $relinfo->{$rel}{is_inner});
326 if (my $clps = $relinfo->{$rel}{rsrc}->_resolve_collapse ({
327 as => $rel_cols->{$rel},
328 _rel_chain => [ @{$args->{_rel_chain}}, $rel ],
329 _parent_info => { underdefined => 1 },
332 # for singles use the idcols wholesale (either there or not)
333 if ($relinfo->{$rel}{is_single}) {
334 push @collapse_sets, $clps->{-identifying_columns};
336 elsif (! $relinfo->{$rel}{fk_map}) {
337 $uncollapsible_chain = 1;
341 my $defined_cols_parent_side;
343 for my $fq_col ( grep { /^$rel\.[^\.]+$/ } keys %{$args->{as}} ) {
344 my ($col) = $fq_col =~ /([^\.]+)$/;
346 $defined_cols_parent_side->{$_} = $args->{as}{$fq_col} for grep
347 { $relinfo->{$rel}{fk_map}{$_} eq $col }
348 keys %{$relinfo->{$rel}{fk_map}}
352 if (my $set = $self->_identifying_column_set([ keys %$defined_cols_parent_side ]) ) {
353 push @collapse_sets, [ sort map { $defined_cols_parent_side->{$_} } @$set ];
356 $uncollapsible_chain = 1;
362 $uncollapsible_chain = 1;
367 unless ($uncollapsible_chain) {
368 # if we got here - we are good to go, but the construction is tricky
369 # since our children will want to include our collapse criteria - we
370 # don't give them anything (safe, since they are all collapsible on their own)
371 # in addition we record the individual collapse possibilities
372 # of all left children node collapsers, and merge them in the rowparser
374 $collapse_map->{-identifying_columns} = [];
375 $collapse_map->{-identifying_columns_variants} = [ sort {
376 (scalar @$a) <=> (scalar @$b) or max(@$a) <=> max(@$b)
381 # stop descending into children if we were called by a parent for first-pass
382 # and don't despair if nothing was found (there may be other parallel branches
384 if ($args->{_parent_info}{underdefined}) {
385 return $collapse_map->{-identifying_columns} ? $collapse_map : undef
387 # nothing down the chain resolved - can't calculate a collapse-map
388 elsif (! $collapse_map->{-identifying_columns}) {
389 $self->throw_exception ( sprintf
390 "Unable to calculate a definitive collapse column set for %s%s: fetch more unique non-nullable columns",
392 @{$args->{_rel_chain}} > 1
393 ? sprintf (' (last member of the %s chain)', join ' -> ', @{$args->{_rel_chain}} )
399 # If we got that far - we are collapsable - GREAT! Now go down all children
400 # a second time, and fill in the rest
402 $collapse_map->{-identifying_columns} = [ __unique_numlist(
403 @{ $args->{_parent_info}{collapse_on_idcols}||[] },
404 @{ $collapse_map->{-identifying_columns} },
408 for my $rel (sort keys %$relinfo) {
410 $collapse_map->{$rel} = $relinfo->{$rel}{rsrc}->_resolve_collapse ({
411 as => { map { $_ => 1 } ( keys %{$rel_cols->{$rel}} ) },
412 _rel_chain => [ @{$args->{_rel_chain}}, $rel],
415 collapse_on_idcols => [ @{$collapse_map->{-identifying_columns}} ],
417 rel_condition => $relinfo->{$rel}{fk_map},
419 is_optional => ! $relinfo->{$rel}{is_inner},
421 # if there is at least one *inner* reverse relationship which is HASH-based (equality only)
422 # we can safely assume that the child can not exist without us
423 rev_rel_is_optional => ( first
424 { ref $_->{cond} eq 'HASH' and ($_->{attrs}{join_type}||'') !~ /^left/i }
425 values %{ $self->reverse_relationship_info($rel) },
428 # if this is a 1:1 our own collapser can be used as a collapse-map
429 # (regardless of left or not)
430 collapser_reusable => (
431 $relinfo->{$rel}{is_single}
433 $relinfo->{$rel}{is_inner}
435 @{$collapse_map->{-identifying_columns}}
440 $collapse_map->{$rel}{-is_single} = 1 if $relinfo->{$rel}{is_single};
441 $collapse_map->{$rel}{-is_optional} ||= 1 unless $relinfo->{$rel}{is_inner};
444 return $collapse_map;
447 # adding a dep on MoreUtils *just* for this is retarded
448 sub __unique_numlist {
449 sort { $a <=> $b } keys %{ {map { $_ => 1 } @_ }}