X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDBIx%2FClass%2FStorage%2FDBIHacks.pm;h=3efd4884a39813da053863b9b494c13038ee5dfe;hb=908aa1bb761ec1da5c061fe9f687598e3f1934bc;hp=c2e13da365a8d9a92b7e2622de4818ab686e25d6;hpb=bac6c4fb44d23391b40e5fcf53809c0ca0c75dc7;p=dbsrgits%2FDBIx-Class.git diff --git a/lib/DBIx/Class/Storage/DBIHacks.pm b/lib/DBIx/Class/Storage/DBIHacks.pm index c2e13da..3efd488 100644 --- a/lib/DBIx/Class/Storage/DBIHacks.pm +++ b/lib/DBIx/Class/Storage/DBIHacks.pm @@ -1,9 +1,10 @@ -package DBIx::Class::Storage::DBIHacks; +package #hide from PAUSE + DBIx::Class::Storage::DBIHacks; # # This module contains code that should never have seen the light of day, # does not belong in the Storage, or is otherwise unfit for public -# display. The arrival of SQLA2 should immediately oboslete 90% of this +# display. The arrival of SQLA2 should immediately obsolete 90% of this # use strict; @@ -12,17 +13,61 @@ use warnings; use base 'DBIx::Class::Storage'; use mro 'c3'; -use Carp::Clan qw/^DBIx::Class/; +use List::Util 'first'; +use Scalar::Util 'blessed'; +use Sub::Name 'subname'; +use namespace::clean; + +# +# This code will remove non-selecting/non-restricting joins from +# {from} specs, aiding the RDBMS query optimizer +# +sub _prune_unused_joins { + my $self = shift; + my ($from, $select, $where, $attrs) = @_; + + return $from unless $self->_use_join_optimizer; + + if (ref $from ne 'ARRAY' || ref $from->[0] ne 'HASH' || ref $from->[1] ne 'ARRAY') { + return $from; # only standard {from} specs are supported + } + + my $aliastypes = $self->_resolve_aliastypes_from_select_args(@_); + + # a grouped set will not be affected by amount of rows. Thus any + # {multiplying} joins can go + delete $aliastypes->{multiplying} if $attrs->{group_by}; + + my @newfrom = $from->[0]; # FROM head is always present + + my %need_joins; + for (values %$aliastypes) { + # add all requested aliases + $need_joins{$_} = 1 for keys %$_; + + # add all their parents (as per joinpath which is an AoH { table => alias }) + $need_joins{$_} = 1 for map { values %$_ } map { @$_ } values %$_; + } + for my $j (@{$from}[1..$#$from]) { + push @newfrom, $j if ( + (! $j->[0]{-alias}) # legacy crap + || + $need_joins{$j->[0]{-alias}} + ); + } + + return \@newfrom; +} # # This is the code producing joined subqueries like: -# SELECT me.*, other.* FROM ( SELECT me.* FROM ... ) JOIN other ON ... +# SELECT me.*, other.* FROM ( SELECT me.* FROM ... ) JOIN other ON ... # sub _adjust_select_args_for_complex_prefetch { my ($self, $from, $select, $where, $attrs) = @_; $self->throw_exception ('Nothing to prefetch... how did we get here?!') - if not @{$attrs->{_prefetch_select}}; + if not @{$attrs->{_prefetch_selector_range}}; $self->throw_exception ('Complex prefetches are not supported on resultsets with a custom from attribute') if (ref $from ne 'ARRAY' || ref $from->[0] ne 'HASH' || ref $from->[1] ne 'ARRAY'); @@ -32,26 +77,17 @@ sub _adjust_select_args_for_complex_prefetch { my $outer_attrs = { %$attrs }; delete $outer_attrs->{$_} for qw/where bind rows offset group_by having/; - my $inner_attrs = { %$attrs }; - delete $inner_attrs->{$_} for qw/for collapse _prefetch_select _collapse_order_by select as/; - - - # bring over all non-collapse-induced order_by into the inner query (if any) - # the outer one will have to keep them all - delete $inner_attrs->{order_by}; - if (my $ord_cnt = @{$outer_attrs->{order_by}} - @{$outer_attrs->{_collapse_order_by}} ) { - $inner_attrs->{order_by} = [ - @{$outer_attrs->{order_by}}[ 0 .. $ord_cnt - 1] - ]; - } - + my $inner_attrs = { %$attrs, _is_internal_subuery => 1 }; + delete $inner_attrs->{$_} for qw/for collapse _prefetch_selector_range select as/; # generate the inner/outer select lists # for inside we consider only stuff *not* brought in by the prefetch # on the outside we substitute any function for its alias my $outer_select = [ @$select ]; my $inner_select = []; - for my $i (0 .. ( @$outer_select - @{$outer_attrs->{_prefetch_select}} - 1) ) { + + my ($p_start, $p_end) = @{$outer_attrs->{_prefetch_selector_range}}; + for my $i (0 .. $p_start - 1, $p_end + 1 .. $#$outer_select) { my $sel = $outer_select->[$i]; if (ref $sel eq 'HASH' ) { @@ -60,124 +96,60 @@ sub _adjust_select_args_for_complex_prefetch { } push @$inner_select, $sel; - } - - # normalize a copy of $from, so it will be easier to work with further - # down (i.e. promote the initial hashref to an AoH) - $from = [ @$from ]; - $from->[0] = [ $from->[0] ]; - my %original_join_info = map { $_->[0]{-alias} => $_->[0] } (@$from); - - - # decide which parts of the join will remain in either part of - # the outer/inner query - - # First we compose a list of which aliases are used in restrictions - # (i.e. conditions/order/grouping/etc). Since we do not have - # introspectable SQLA, we fall back to ugly scanning of raw SQL for - # WHERE, and for pieces of ORDER BY in order to determine which aliases - # need to appear in the resulting sql. - # It may not be very efficient, but it's a reasonable stop-gap - # Also unqualified column names will not be considered, but more often - # than not this is actually ok - # - # In the same loop we enumerate part of the selection aliases, as - # it requires the same sqla hack for the time being - my ($restrict_aliases, $select_aliases, $prefetch_aliases); - { - # produce stuff unquoted, so it can be scanned - my $sql_maker = $self->sql_maker; - local $sql_maker->{quote_char}; - my $sep = $self->_sql_maker_opts->{name_sep} || '.'; - $sep = "\Q$sep\E"; - - my $non_prefetch_select_sql = $sql_maker->_recurse_fields ($inner_select); - my $prefetch_select_sql = $sql_maker->_recurse_fields ($outer_attrs->{_prefetch_select}); - my $where_sql = $sql_maker->where ($where); - my $group_by_sql = $sql_maker->_order_by({ - map { $_ => $inner_attrs->{$_} } qw/group_by having/ - }); - my @non_prefetch_order_by_chunks = (map - { ref $_ ? $_->[0] : $_ } - $sql_maker->_order_by_chunks ($inner_attrs->{order_by}) - ); - - - for my $alias (keys %original_join_info) { - my $seen_re = qr/\b $alias $sep/x; - - for my $piece ($where_sql, $group_by_sql, @non_prefetch_order_by_chunks ) { - if ($piece =~ $seen_re) { - $restrict_aliases->{$alias} = 1; - } - } - - if ($non_prefetch_select_sql =~ $seen_re) { - $select_aliases->{$alias} = 1; - } - - if ($prefetch_select_sql =~ $seen_re) { - $prefetch_aliases->{$alias} = 1; - } - } + push @{$inner_attrs->{as}}, $attrs->{as}[$i]; } - # Add any non-left joins to the restriction list (such joins are indeed restrictions) - for my $j (values %original_join_info) { - my $alias = $j->{-alias} or next; - $restrict_aliases->{$alias} = 1 if ( - (not $j->{-join_type}) - or - ($j->{-join_type} !~ /^left (?: \s+ outer)? $/xi) - ); - } + # construct the inner $from and lock it in a subquery + # we need to prune first, because this will determine if we need a group_by below + # the fake group_by is so that the pruner throws away all non-selecting, non-restricting + # multijoins (since we def. do not care about those inside the subquery) - # mark all join parents as mentioned - # (e.g. join => { cds => 'tracks' } - tracks will need to bring cds too ) - for my $collection ($restrict_aliases, $select_aliases) { - for my $alias (keys %$collection) { - $collection->{$_} = 1 - for (@{ $original_join_info{$alias}{-join_path} || [] }); - } - } + my $inner_subq = do { - # construct the inner $from for the subquery - my %inner_joins = (map { %{$_ || {}} } ($restrict_aliases, $select_aliases) ); - my @inner_from; - for my $j (@$from) { - push @inner_from, $j if $inner_joins{$j->[0]{-alias}}; - } + # must use it here regardless of user requests + local $self->{_use_join_optimizer} = 1; - # if a multi-type join was needed in the subquery ("multi" is indicated by - # presence in {collapse}) - add a group_by to simulate the collapse in the subq - unless ($inner_attrs->{group_by}) { - for my $alias (keys %inner_joins) { + my $inner_from = $self->_prune_unused_joins ($from, $inner_select, $where, { + group_by => ['dummy'], %$inner_attrs, + }); - # the dot comes from some weirdness in collapse - # remove after the rewrite - if ($attrs->{collapse}{".$alias"}) { - $inner_attrs->{group_by} ||= $inner_select; - last; - } + my $inner_aliastypes = + $self->_resolve_aliastypes_from_select_args( $inner_from, $inner_select, $where, $inner_attrs ); + + # we need to simulate collapse in the subq if a multiplying join is pulled + # by being a non-selecting restrictor + if ( + ! $inner_attrs->{group_by} + and + first { + $inner_aliastypes->{restricting}{$_} + and + ! $inner_aliastypes->{selecting}{$_} + } ( keys %{$inner_aliastypes->{multiplying}||{}} ) + ) { + my $unprocessed_order_chunks; + ($inner_attrs->{group_by}, $unprocessed_order_chunks) = $self->_group_over_selection ( + $inner_from, $inner_select, $inner_attrs->{order_by} + ); + + $self->throw_exception ( + 'A required group_by clause could not be constructed automatically due to a complex ' + . 'order_by criteria. Either order_by columns only (no functions) or construct a suitable ' + . 'group_by by hand' + ) if $unprocessed_order_chunks; } - } - - # demote the inner_from head - $inner_from[0] = $inner_from[0][0]; - # generate the subquery - my $subq = $self->_select_args_to_query ( - \@inner_from, - $inner_select, - $where, - $inner_attrs, - ); + # we already optimized $inner_from above + local $self->{_use_join_optimizer} = 0; - my $subq_joinspec = { - -alias => $attrs->{alias}, - -source_handle => $inner_from[0]{-source_handle}, - $attrs->{alias} => $subq, + # generate the subquery + $self->_select_args_to_query ( + $inner_from, + $inner_select, + $where, + $inner_attrs, + ); }; # Generate the outer from - this is relatively easy (really just replace @@ -190,12 +162,21 @@ sub _adjust_select_args_for_complex_prefetch { # - it is part of the restrictions, in which case we need to collapse the outer # result by tackling yet another group_by to the outside of the query + $from = [ @$from ]; + # so first generate the outer_from, up to the substitution point my @outer_from; while (my $j = shift @$from) { + $j = [ $j ] unless ref $j eq 'ARRAY'; # promote the head-from to an AoH + if ($j->[0]{-alias} eq $attrs->{alias}) { # time to swap + push @outer_from, [ - $subq_joinspec, + { + -alias => $attrs->{alias}, + -rsrc => $j->[0]{-rsrc}, + $attrs->{alias} => $inner_subq, + }, @{$j}[1 .. $#$j], ]; last; # we'll take care of what's left in $from below @@ -205,40 +186,52 @@ sub _adjust_select_args_for_complex_prefetch { } } + # scan the *remaining* from spec against different attributes, and see which joins are needed + # in what role + my $outer_aliastypes = + $self->_resolve_aliastypes_from_select_args( $from, $outer_select, $where, $outer_attrs ); + + # unroll parents + my ($outer_select_chain, $outer_restrict_chain) = map { +{ + map { $_ => 1 } map { values %$_} map { @$_ } values %{ $outer_aliastypes->{$_} || {} } + } } qw/selecting restricting/; + # see what's left - throw away if not selecting/restricting - # also throw in a group_by if restricting to guard against - # cross-join explosions - # + # also throw in a group_by if a non-selecting multiplier, + # to guard against cross-join explosions + my $need_outer_group_by; while (my $j = shift @$from) { my $alias = $j->[0]{-alias}; - if ($select_aliases->{$alias} || $prefetch_aliases->{$alias}) { - push @outer_from, $j; + if ( + $outer_select_chain->{$alias} + ) { + push @outer_from, $j } - elsif ($restrict_aliases->{$alias}) { + elsif ($outer_restrict_chain->{$alias}) { push @outer_from, $j; - - # FIXME - this should be obviated by SQLA2, as I'll be able to - # have restrict_inner and restrict_outer... or something to that - # effect... I think... - - # FIXME2 - I can't find a clean way to determine if a particular join - # is a multi - instead I am just treating everything as a potential - # explosive join (ribasushi) - # - # if (my $handle = $j->[0]{-source_handle}) { - # my $rsrc = $handle->resolve; - # ... need to bail out of the following if this is not a multi, - # as it will be much easier on the db ... - - $outer_attrs->{group_by} ||= $outer_select; - # } + $need_outer_group_by ||= $outer_aliastypes->{multiplying}{$alias} ? 1 : 0; } } # demote the outer_from head $outer_from[0] = $outer_from[0][0]; + if ($need_outer_group_by and ! $outer_attrs->{group_by}) { + + my $unprocessed_order_chunks; + ($outer_attrs->{group_by}, $unprocessed_order_chunks) = $self->_group_over_selection ( + \@outer_from, $outer_select, $outer_attrs->{order_by} + ); + + $self->throw_exception ( + 'A required group_by clause could not be constructed automatically due to a complex ' + . 'order_by criteria. Either order_by columns only (no functions) or construct a suitable ' + . 'group_by by hand' + ) if $unprocessed_order_chunks; + + } + # This is totally horrific - the $where ends up in both the inner and outer query # Unfortunately not much can be done until SQLA2 introspection arrives, and even # then if where conditions apply to the *right* side of the prefetch, you may have @@ -249,6 +242,186 @@ sub _adjust_select_args_for_complex_prefetch { return (\@outer_from, $outer_select, $where, $outer_attrs); } +# +# I KNOW THIS SUCKS! GET SQLA2 OUT THE DOOR SO THIS CAN DIE! +# +# Due to a lack of SQLA2 we fall back to crude scans of all the +# select/where/order/group attributes, in order to determine what +# aliases are neded to fulfill the query. This information is used +# throughout the code to prune unnecessary JOINs from the queries +# in an attempt to reduce the execution time. +# Although the method is pretty horrific, the worst thing that can +# happen is for it to fail due to some scalar SQL, which in turn will +# result in a vocal exception. +sub _resolve_aliastypes_from_select_args { + my ( $self, $from, $select, $where, $attrs ) = @_; + + $self->throw_exception ('Unable to analyze custom {from}') + if ref $from ne 'ARRAY'; + + # what we will return + my $aliases_by_type; + + # see what aliases are there to work with + my $alias_list; + for (@$from) { + my $j = $_; + $j = $j->[0] if ref $j eq 'ARRAY'; + my $al = $j->{-alias} + or next; + + $alias_list->{$al} = $j; + $aliases_by_type->{multiplying}{$al} ||= $j->{-join_path}||[] if ( + # not array == {from} head == can't be multiplying + ( ref($_) eq 'ARRAY' and ! $j->{-is_single} ) + or + # a parent of ours is already a multiplier + ( grep { $aliases_by_type->{multiplying}{$_} } @{ $j->{-join_path}||[] } ) + ); + } + + # get a column to source/alias map (including unqualified ones) + my $colinfo = $self->_resolve_column_info ($from); + + # set up a botched SQLA + my $sql_maker = $self->sql_maker; + + # these are throw away results, do not pollute the bind stack + local $sql_maker->{select_bind}; + local $sql_maker->{where_bind}; + local $sql_maker->{group_bind}; + local $sql_maker->{having_bind}; + + # we can't scan properly without any quoting (\b doesn't cut it + # everywhere), so unless there is proper quoting set - use our + # own weird impossible character. + # Also in the case of no quoting, we need to explicitly disable + # name_sep, otherwise sorry nasty legacy syntax like + # { 'count(foo.id)' => { '>' => 3 } } will stop working >:( + local $sql_maker->{quote_char} = $sql_maker->{quote_char}; + local $sql_maker->{name_sep} = $sql_maker->{name_sep}; + + unless (defined $sql_maker->{quote_char} and length $sql_maker->{quote_char}) { + $sql_maker->{quote_char} = ["\x00", "\xFF"]; + # if we don't unset it we screw up retarded but unfortunately working + # 'MAX(foo.bar)' => { '>', 3 } + $sql_maker->{name_sep} = ''; + } + + my ($lquote, $rquote, $sep) = map { quotemeta $_ } ($sql_maker->_quote_chars, $sql_maker->name_sep); + + # generate sql chunks + my $to_scan = { + restricting => [ + $sql_maker->_recurse_where ($where), + $sql_maker->_parse_rs_attrs ({ + map { $_ => $attrs->{$_} } (qw/group_by having/) + }), + ], + selecting => [ + $sql_maker->_recurse_fields ($select), + ( map { $_->[0] } $self->_extract_order_criteria ($attrs->{order_by}, $sql_maker) ), + ], + }; + + # throw away empty chunks + $_ = [ map { $_ || () } @$_ ] for values %$to_scan; + + # first loop through all fully qualified columns and get the corresponding + # alias (should work even if they are in scalarrefs) + for my $alias (keys %$alias_list) { + my $al_re = qr/ + $lquote $alias $rquote $sep + | + \b $alias \. + /x; + + for my $type (keys %$to_scan) { + for my $piece (@{$to_scan->{$type}}) { + $aliases_by_type->{$type}{$alias} ||= $alias_list->{$alias}{-join_path}||[] + if ($piece =~ $al_re); + } + } + } + + # now loop through unqualified column names, and try to locate them within + # the chunks + for my $col (keys %$colinfo) { + next if $col =~ / \. /x; # if column is qualified it was caught by the above + + my $col_re = qr/ $lquote $col $rquote /x; + + for my $type (keys %$to_scan) { + for my $piece (@{$to_scan->{$type}}) { + if ($piece =~ $col_re) { + my $alias = $colinfo->{$col}{-source_alias}; + $aliases_by_type->{$type}{$alias} ||= $alias_list->{$alias}{-join_path}||[]; + } + } + } + } + + # Add any non-left joins to the restriction list (such joins are indeed restrictions) + for my $j (values %$alias_list) { + my $alias = $j->{-alias} or next; + $aliases_by_type->{restricting}{$alias} ||= $j->{-join_path}||[] if ( + (not $j->{-join_type}) + or + ($j->{-join_type} !~ /^left (?: \s+ outer)? $/xi) + ); + } + + return $aliases_by_type; +} + +# This is the engine behind { distinct => 1 } +sub _group_over_selection { + my ($self, $from, $select, $order_by) = @_; + + my $rs_column_list = $self->_resolve_column_info ($from); + + my (@group_by, %group_index); + + # the logic is: if it is a { func => val } we assume an aggregate, + # otherwise if \'...' or \[...] we assume the user knows what is + # going on thus group over it + for (@$select) { + if (! ref($_) or ref ($_) ne 'HASH' ) { + push @group_by, $_; + $group_index{$_}++; + if ($rs_column_list->{$_} and $_ !~ /\./ ) { + # add a fully qualified version as well + $group_index{"$rs_column_list->{$_}{-source_alias}.$_"}++; + } + } + } + + # add any order_by parts that are not already present in the group_by + # we need to be careful not to add any named functions/aggregates + # i.e. order_by => [ ... { count => 'foo' } ... ] + my @leftovers; + for ($self->_extract_order_criteria($order_by)) { + # only consider real columns (for functions the user got to do an explicit group_by) + if (@$_ != 1) { + push @leftovers, $_; + next; + } + my $chunk = $_->[0]; + my $colinfo = $rs_column_list->{$chunk} or do { + push @leftovers, $_; + next; + }; + + $chunk = "$colinfo->{-source_alias}.$chunk" if $chunk !~ /\./; + push @group_by, $chunk unless $group_index{$chunk}++; + } + + return wantarray + ? (\@group_by, (@leftovers ? \@leftovers : undef) ) + : \@group_by + ; +} + sub _resolve_ident_sources { my ($self, $ident) = @_; @@ -257,7 +430,7 @@ sub _resolve_ident_sources { # the reason this is so contrived is that $ident may be a {from} # structure, specifying multiple tables to join - if ( Scalar::Util::blessed($ident) && $ident->isa("DBIx::Class::ResultSource") ) { + if ( blessed $ident && $ident->isa("DBIx::Class::ResultSource") ) { # this is compat mode for insert/update/delete which do not deal with aliases $alias2source->{me} = $ident; $rs_alias = 'me'; @@ -274,8 +447,8 @@ sub _resolve_ident_sources { $tabinfo = $_->[0]; } - $alias2source->{$tabinfo->{-alias}} = $tabinfo->{-source_handle}->resolve - if ($tabinfo->{-source_handle}); + $alias2source->{$tabinfo->{-alias}} = $tabinfo->{-rsrc} + if ($tabinfo->{-rsrc}); } } @@ -287,16 +460,13 @@ sub _resolve_ident_sources { # returns { $column_name => \%column_info, ... } # also note: this adds -result_source => $rsrc to the column info # -# usage: -# my $col_sources = $self->_resolve_column_info($ident, @column_names); +# If no columns_names are supplied returns info about *all* columns +# for all sources sub _resolve_column_info { my ($self, $ident, $colnames) = @_; my ($alias2src, $root_alias) = $self->_resolve_ident_sources($ident); - my $sep = $self->_sql_maker_opts->{name_sep} || '.'; - $sep = "\Q$sep\E"; - - my (%return, %seen_cols); + my (%seen_cols, @auto_colnames); # compile a global list of column names, to be able to properly # disambiguate unqualified column names (if at all possible) @@ -304,29 +474,43 @@ sub _resolve_column_info { my $rsrc = $alias2src->{$alias}; for my $colname ($rsrc->columns) { push @{$seen_cols{$colname}}, $alias; + push @auto_colnames, "$alias.$colname" unless $colnames; } } - COLUMN: + $colnames ||= [ + @auto_colnames, + grep { @{$seen_cols{$_}} == 1 } (keys %seen_cols), + ]; + + my (%return, $colinfos); foreach my $col (@$colnames) { - my ($alias, $colname) = $col =~ m/^ (?: ([^$sep]+) $sep)? (.+) $/x; + my ($source_alias, $colname) = $col =~ m/^ (?: ([^\.]+) \. )? (.+) $/x; - unless ($alias) { - # see if the column was seen exactly once (so we know which rsrc it came from) - if ($seen_cols{$colname} and @{$seen_cols{$colname}} == 1) { - $alias = $seen_cols{$colname}[0]; - } - else { - next COLUMN; - } - } + # if the column was seen exactly once - we know which rsrc it came from + $source_alias ||= $seen_cols{$colname}[0] + if ($seen_cols{$colname} and @{$seen_cols{$colname}} == 1); - my $rsrc = $alias2src->{$alias}; - $return{$col} = $rsrc && { - %{$rsrc->column_info($colname)}, + next unless $source_alias; + + my $rsrc = $alias2src->{$source_alias} + or next; + + $return{$col} = { + %{ + ( $colinfos->{$source_alias} ||= $rsrc->columns_info )->{$colname} + || + $self->throw_exception( + "No such column '$colname' on source " . $rsrc->source_name + ); + }, -result_source => $rsrc, - -source_alias => $alias, + -source_alias => $source_alias, + -fq_colname => $col eq $colname ? "$source_alias.$col" : $col, + -colname => $colname, }; + + $return{"$source_alias.$colname"} = $return{$col} if $col eq $colname; } return \%return; @@ -347,7 +531,7 @@ sub _resolve_column_info { # the top of the stack, and if not - make sure the chain is inner-joined down # to the root. # -sub _straight_join_to_node { +sub _inner_join_to_node { my ($self, $from, $alias) = @_; # subqueries and other oddness are naturally not supported @@ -379,9 +563,9 @@ sub _straight_join_to_node { # So it looks like we will have to switch some stuff around. # local() is useless here as we will be leaving the scope # anyway, and deep cloning is just too fucking expensive - # So replace the first hashref in the node arrayref manually + # So replace the first hashref in the node arrayref manually my @new_from = ($from->[0]); - my $sw_idx = { map { $_ => 1 } @$switch_branch }; + my $sw_idx = { map { (values %$_), 1 } @$switch_branch }; #there's one k/v per join-path for my $j (@{$from}[1 .. $#$from]) { my $jalias = $j->[0]{-alias}; @@ -402,61 +586,146 @@ sub _straight_join_to_node { return \@new_from; } -# Most databases do not allow aliasing of tables in UPDATE/DELETE. Thus -# a condition containing 'me' or other table prefixes will not work -# at all. What this code tries to do (badly) is introspect the condition -# and remove all column qualifiers. If it bails out early (returns undef) -# the calling code should try another approach (e.g. a subquery) -sub _strip_cond_qualifiers { - my ($self, $where) = @_; - - my $cond = {}; - - # No-op. No condition, we're updating/deleting everything - return $cond unless $where; - - if (ref $where eq 'ARRAY') { - $cond = [ - map { - my %hash; - foreach my $key (keys %{$_}) { - $key =~ /([^.]+)$/; - $hash{$1} = $_->{$key}; - } - \%hash; - } @$where - ]; - } - elsif (ref $where eq 'HASH') { - if ( (keys %$where) == 1 && ( (keys %{$where})[0] eq '-and' )) { - $cond->{-and} = []; - my @cond = @{$where->{-and}}; - for (my $i = 0; $i < @cond; $i++) { - my $entry = $cond[$i]; - my $hash; - if (ref $entry eq 'HASH') { - $hash = $self->_strip_cond_qualifiers($entry); +# yet another atrocity: attempt to extract all columns from a +# where condition by hooking _quote +sub _extract_condition_columns { + my ($self, $cond, $sql_maker) = @_; + + return [] unless $cond; + + $sql_maker ||= $self->{_sql_ident_capturer} ||= do { + # FIXME - replace with a Moo trait + my $orig_sm_class = ref $self->sql_maker; + my $smic_class = "${orig_sm_class}::_IdentCapture_"; + + unless ($smic_class->isa('SQL::Abstract')) { + + no strict 'refs'; + *{"${smic_class}::_quote"} = subname "${smic_class}::_quote" => sub { + my ($self, $ident) = @_; + if (ref $ident eq 'SCALAR') { + $ident = $$ident; + my $storage_quotes = $self->sql_quote_char || '"'; + my ($ql, $qr) = map + { quotemeta $_ } + (ref $storage_quotes eq 'ARRAY' ? @$storage_quotes : ($storage_quotes) x 2 ) + ; + + while ($ident =~ / + $ql (\w+) $qr + | + ([\w\.]+) + /xg) { + $self->{_captured_idents}{$1||$2}++; + } } else { - $entry =~ /([^.]+)$/; - $hash->{$1} = $cond[++$i]; + $self->{_captured_idents}{$ident}++; } - push @{$cond->{-and}}, $hash; - } + return $ident; + }; + + *{"${smic_class}::_get_captured_idents"} = subname "${smic_class}::_get_captures" => sub { + (delete shift->{_captured_idents}) || {}; + }; + + $self->inject_base ($smic_class, $orig_sm_class); + } - else { - foreach my $key (keys %$where) { - $key =~ /([^.]+)$/; - $cond->{$1} = $where->{$key}; - } + + $smic_class->new(); + }; + + $sql_maker->_recurse_where($cond); + + return [ sort keys %{$sql_maker->_get_captured_idents} ]; +} + +sub _extract_order_criteria { + my ($self, $order_by, $sql_maker) = @_; + + my $parser = sub { + my ($sql_maker, $order_by) = @_; + + return scalar $sql_maker->_order_by_chunks ($order_by) + unless wantarray; + + my @chunks; + for ($sql_maker->_order_by_chunks ($order_by) ) { + my $chunk = ref $_ ? $_ : [ $_ ]; + $chunk->[0] =~ s/\s+ (?: ASC|DESC ) \s* $//ix; + push @chunks, $chunk; } + + return @chunks; + }; + + if ($sql_maker) { + return $parser->($sql_maker, $order_by); } else { - return undef; + $sql_maker = $self->sql_maker; + local $sql_maker->{quote_char}; + return $parser->($sql_maker, $order_by); } +} + +sub _order_by_is_stable { + my ($self, $ident, $order_by, $where) = @_; + + my $colinfo = $self->_resolve_column_info($ident, [ + (map { $_->[0] } $self->_extract_order_criteria($order_by)), + $where ? @{$self->_extract_fixed_condition_columns($where)} :(), + ]); - return $cond; + return undef unless keys %$colinfo; + + my $cols_per_src; + $cols_per_src->{$_->{-source_alias}}{$_->{-colname}} = $_ for values %$colinfo; + + for (values %$cols_per_src) { + my $src = (values %$_)[0]->{-result_source}; + return 1 if $src->_identifying_column_set($_); + } + + return undef; } +# returns an arrayref of column names which *definitely* have som +# sort of non-nullable equality requested in the given condition +# specification. This is used to figure out if a resultset is +# constrained to a column which is part of a unique constraint, +# which in turn allows us to better predict how ordering will behave +# etc. +# +# this is a rudimentary, incomplete, and error-prone extractor +# however this is OK - it is conservative, and if we can not find +# something that is in fact there - the stack will recover gracefully +# Also - DQ and the mst it rode in on will save us all RSN!!! +sub _extract_fixed_condition_columns { + my ($self, $where, $nested) = @_; + + return unless ref $where eq 'HASH'; + + my @cols; + for my $lhs (keys %$where) { + if ($lhs =~ /^\-and$/i) { + push @cols, ref $where->{$lhs} eq 'ARRAY' + ? ( map { $self->_extract_fixed_condition_columns($_, 1) } @{$where->{$lhs}} ) + : $self->_extract_fixed_condition_columns($where->{$lhs}, 1) + ; + } + elsif ($lhs !~ /^\-/) { + my $val = $where->{$lhs}; + + push @cols, $lhs if (defined $val and ( + ! ref $val + or + (ref $val eq 'HASH' and keys %$val == 1 and defined $val->{'='}) + )); + } + } + return $nested ? @cols : \@cols; +} 1;