make _determine_driver more reentrant
[dbsrgits/DBIx-Class-Historic.git] / lib / DBIx / Class / SQLAHacks.pm
CommitLineData
6f4ddea1 1package # Hide from PAUSE
855c6fd0 2 DBIx::Class::SQLAHacks;
6f4ddea1 3
998373c2 4# This module is a subclass of SQL::Abstract::Limit and includes a number
5# of DBIC-specific workarounds, not yet suitable for inclusion into the
6# SQLA core
7
6f4ddea1 8use base qw/SQL::Abstract::Limit/;
e3764383 9use strict;
10use warnings;
b2b22cd6 11use Carp::Clan qw/^DBIx::Class|^SQL::Abstract/;
12
13BEGIN {
14 # reinstall the carp()/croak() functions imported into SQL::Abstract
15 # as Carp and Carp::Clan do not like each other much
16 no warnings qw/redefine/;
17 no strict qw/refs/;
18 for my $f (qw/carp croak/) {
329d7385 19
b2b22cd6 20 my $orig = \&{"SQL::Abstract::$f"};
21 *{"SQL::Abstract::$f"} = sub {
22
23 local $Carp::CarpLevel = 1; # even though Carp::Clan ignores this, $orig will not
24
329d7385 25 if (Carp::longmess() =~ /DBIx::Class::SQLAHacks::[\w]+ .+? called \s at/x) {
b2b22cd6 26 __PACKAGE__->can($f)->(@_);
27 }
28 else {
29 $orig->(@_);
30 }
31 }
32 }
33}
6f4ddea1 34
998373c2 35
36# Tries to determine limit dialect.
37#
6f4ddea1 38sub new {
39 my $self = shift->SUPER::new(@_);
40
41 # This prevents the caching of $dbh in S::A::L, I believe
42 # If limit_dialect is a ref (like a $dbh), go ahead and replace
43 # it with what it resolves to:
44 $self->{limit_dialect} = $self->_find_syntax($self->{limit_dialect})
45 if ref $self->{limit_dialect};
46
47 $self;
48}
49
6f4ddea1 50# Some databases (sqlite) do not handle multiple parenthesis
998373c2 51# around in/between arguments. A tentative x IN ( (1, 2 ,3) )
6f4ddea1 52# is interpreted as x IN 1 or something similar.
53#
54# Since we currently do not have access to the SQLA AST, resort
55# to barbaric mutilation of any SQL supplied in literal form
6f4ddea1 56sub _strip_outer_paren {
57 my ($self, $arg) = @_;
58
59 return $self->_SWITCH_refkind ($arg, {
60 ARRAYREFREF => sub {
61 $$arg->[0] = __strip_outer_paren ($$arg->[0]);
62 return $arg;
63 },
64 SCALARREF => sub {
65 return \__strip_outer_paren( $$arg );
66 },
67 FALLBACK => sub {
68 return $arg
69 },
70 });
71}
72
73sub __strip_outer_paren {
74 my $sql = shift;
75
76 if ($sql and not ref $sql) {
77 while ($sql =~ /^ \s* \( (.*) \) \s* $/x ) {
78 $sql = $1;
79 }
80 }
81
82 return $sql;
83}
84
85sub _where_field_IN {
86 my ($self, $lhs, $op, $rhs) = @_;
87 $rhs = $self->_strip_outer_paren ($rhs);
88 return $self->SUPER::_where_field_IN ($lhs, $op, $rhs);
89}
90
91sub _where_field_BETWEEN {
92 my ($self, $lhs, $op, $rhs) = @_;
93 $rhs = $self->_strip_outer_paren ($rhs);
94 return $self->SUPER::_where_field_BETWEEN ($lhs, $op, $rhs);
95}
96
15827712 97# Slow but ANSI standard Limit/Offset support. DB2 uses this
6f4ddea1 98sub _RowNumberOver {
99 my ($self, $sql, $order, $rows, $offset ) = @_;
100
101 $offset += 1;
03e1d9af 102 my $last = $rows + $offset - 1;
6f4ddea1 103 my ( $order_by ) = $self->_order_by( $order );
104
105 $sql = <<"SQL";
106SELECT * FROM
107(
108 SELECT Q1.*, ROW_NUMBER() OVER( ) AS ROW_NUM FROM (
109 $sql
110 $order_by
111 ) Q1
112) Q2
113WHERE ROW_NUM BETWEEN $offset AND $last
114
115SQL
116
117 return $sql;
118}
119
15827712 120# Crappy Top based Limit/Offset support. MSSQL uses this currently,
121# but may have to switch to RowNumberOver one day
122sub _Top {
123 my ( $self, $sql, $order, $rows, $offset ) = @_;
124
b1e1d073 125 # mangle the input sql so it can be properly aliased in the outer queries
126 $sql =~ s/^ \s* SELECT \s+ (.+?) \s+ (?=FROM)//ix
127 or croak "Unrecognizable SELECT: $sql";
42e5b103 128 my $sql_select = $1;
129 my @sql_select = split (/\s*,\s*/, $sql_select);
130
131 # we can't support subqueries (in fact MSSQL can't) - croak
132 if (@sql_select != @{$self->{_dbic_rs_attrs}{select}}) {
133 croak (sprintf (
134 'SQL SELECT did not parse cleanly - retrieved %d comma separated elements, while '
135 . 'the resultset select attribure contains %d elements: %s',
136 scalar @sql_select,
137 scalar @{$self->{_dbic_rs_attrs}{select}},
138 $sql_select,
139 ));
140 }
b1e1d073 141
42e5b103 142 my $name_sep = $self->name_sep || '.';
ac93965c 143 my $esc_name_sep = "\Q$name_sep\E";
144 my $col_re = qr/ ^ (?: (.+) $esc_name_sep )? ([^$esc_name_sep]+) $ /x;
145
146 my $rs_alias = $self->{_dbic_rs_attrs}{alias};
147 my $quoted_rs_alias = $self->_quote ($rs_alias);
b1e1d073 148
42e5b103 149 # construct the new select lists, rename(alias) some columns if necessary
150 my (@outer_select, @inner_select, %seen_names, %col_aliases, %outer_col_aliases);
b1e1d073 151
42e5b103 152 for (@{$self->{_dbic_rs_attrs}{select}}) {
153 next if ref $_;
154 my ($table, $orig_colname) = ( $_ =~ $col_re );
155 next unless $table;
156 $seen_names{$orig_colname}++;
157 }
b1e1d073 158
42e5b103 159 for my $i (0 .. $#sql_select) {
b1e1d073 160
42e5b103 161 my $colsel_arg = $self->{_dbic_rs_attrs}{select}[$i];
162 my $colsel_sql = $sql_select[$i];
b1e1d073 163
42e5b103 164 # this may or may not work (in case of a scalarref or something)
165 my ($table, $orig_colname) = ( $colsel_arg =~ $col_re );
b1e1d073 166
42e5b103 167 my $quoted_alias;
168 # do not attempt to understand non-scalar selects - alias numerically
169 if (ref $colsel_arg) {
170 $quoted_alias = $self->_quote ('column_' . (@inner_select + 1) );
171 }
172 # column name seen more than once - alias it
ed4cdb4f 173 elsif ($orig_colname &&
174 ($seen_names{$orig_colname} && $seen_names{$orig_colname} > 1) ) {
42e5b103 175 $quoted_alias = $self->_quote ("${table}__${orig_colname}");
176 }
b1e1d073 177
42e5b103 178 # we did rename - make a record and adjust
179 if ($quoted_alias) {
180 # alias inner
181 push @inner_select, "$colsel_sql AS $quoted_alias";
182
183 # push alias to outer
184 push @outer_select, $quoted_alias;
185
186 # Any aliasing accumulated here will be considered
187 # both for inner and outer adjustments of ORDER BY
188 $self->__record_alias (
189 \%col_aliases,
190 $quoted_alias,
191 $colsel_arg,
192 $table ? $orig_colname : undef,
193 );
b1e1d073 194 }
195
42e5b103 196 # otherwise just leave things intact inside, and use the abbreviated one outside
197 # (as we do not have table names anymore)
198 else {
199 push @inner_select, $colsel_sql;
200
201 my $outer_quoted = $self->_quote ($orig_colname); # it was not a duplicate so should just work
202 push @outer_select, $outer_quoted;
203 $self->__record_alias (
204 \%outer_col_aliases,
205 $outer_quoted,
206 $colsel_arg,
207 $table ? $orig_colname : undef,
208 );
209 }
b1e1d073 210 }
211
212 my $outer_select = join (', ', @outer_select );
42e5b103 213 my $inner_select = join (', ', @inner_select );
b1e1d073 214
42e5b103 215 %outer_col_aliases = (%outer_col_aliases, %col_aliases);
b1e1d073 216
217 # deal with order
15827712 218 croak '$order supplied to SQLAHacks limit emulators must be a hash'
219 if (ref $order ne 'HASH');
220
8f6dbee9 221 $order = { %$order }; #copy
222
02d133f0 223 my $req_order = $order->{order_by};
15827712 224
e2db8319 225 # examine normalized version, collapses nesting
226 my $limit_order;
227 if (scalar $self->_order_by_chunks ($req_order)) {
228 $limit_order = $req_order;
229 }
230 else {
e2db8319 231 $limit_order = [ map
232 { join ('', $rs_alias, $name_sep, $_ ) }
233 ( $self->{_dbic_rs_attrs}{_source_handle}->resolve->primary_columns )
234 ];
235 }
1cbd3034 236
42e5b103 237 my ( $order_by_inner, $order_by_outer ) = $self->_order_directions($limit_order);
238 my $order_by_requested = $self->_order_by ($req_order);
15827712 239
64c7c000 240 # generate the rest
e2db8319 241 delete $order->{order_by};
8f6dbee9 242 my $grpby_having = $self->_order_by ($order);
243
64c7c000 244 # short circuit for counts - the ordering complexity is needless
245 if ($self->{_dbic_rs_attrs}{-for_count_only}) {
246 return "SELECT TOP $rows $inner_select $sql $grpby_having $order_by_outer";
247 }
248
42e5b103 249 # we can't really adjust the order_by columns, as introspection is lacking
250 # resort to simple substitution
251 for my $col (keys %outer_col_aliases) {
252 for ($order_by_requested, $order_by_outer) {
253 $_ =~ s/\s+$col\s+/ $outer_col_aliases{$col} /g;
b1e1d073 254 }
255 }
42e5b103 256 for my $col (keys %col_aliases) {
9c1ffdde 257 $order_by_inner =~ s/\s+$col\s+/ $col_aliases{$col} /g;
42e5b103 258 }
15827712 259
15827712 260
42e5b103 261 my $inner_lim = $rows + $offset;
15827712 262
618a0fe3 263 $sql = "SELECT TOP $inner_lim $inner_select $sql $grpby_having $order_by_inner";
42e5b103 264
265 if ($offset) {
266 $sql = <<"SQL";
b1e1d073 267
268 SELECT TOP $rows $outer_select FROM
15827712 269 (
42e5b103 270 $sql
ac93965c 271 ) $quoted_rs_alias
15827712 272 $order_by_outer
b1e1d073 273SQL
274
42e5b103 275 }
15827712 276
42e5b103 277 if ($order_by_requested) {
b1e1d073 278 $sql = <<"SQL";
15827712 279
42e5b103 280 SELECT $outer_select FROM
ac93965c 281 ( $sql ) $quoted_rs_alias
282 $order_by_requested
15827712 283SQL
b1e1d073 284
285 }
286
ac93965c 287 $sql =~ s/\s*\n\s*/ /g; # parsing out multiline statements is harder than a single line
b1e1d073 288 return $sql;
15827712 289}
290
42e5b103 291# action at a distance to shorten Top code above
292sub __record_alias {
293 my ($self, $register, $alias, $fqcol, $col) = @_;
294
295 # record qualified name
296 $register->{$fqcol} = $alias;
297 $register->{$self->_quote($fqcol)} = $alias;
298
299 return unless $col;
300
b6d347e0 301 # record unqualified name, undef (no adjustment) if a duplicate is found
42e5b103 302 if (exists $register->{$col}) {
303 $register->{$col} = undef;
304 }
305 else {
306 $register->{$col} = $alias;
307 }
308
309 $register->{$self->_quote($col)} = $register->{$col};
15827712 310}
311
312
6f4ddea1 313
314# While we're at it, this should make LIMIT queries more efficient,
315# without digging into things too deeply
6f4ddea1 316sub _find_syntax {
317 my ($self, $syntax) = @_;
ac788c46 318 return $self->{_cached_syntax} ||= $self->SUPER::_find_syntax($syntax);
6f4ddea1 319}
320
ec7cfd36 321my $for_syntax = {
322 update => 'FOR UPDATE',
323 shared => 'FOR SHARE',
324};
998373c2 325# Quotes table names, handles "limit" dialects (e.g. where rownum between x and
326# y), supports SELECT ... FOR UPDATE and SELECT ... FOR SHARE.
6f4ddea1 327sub select {
328 my ($self, $table, $fields, $where, $order, @rest) = @_;
1cbd3034 329
330 $self->{"${_}_bind"} = [] for (qw/having from order/);
db56cf3d 331
c2b7c5dc 332 if (not ref($table) or ref($table) eq 'SCALAR') {
6f4ddea1 333 $table = $self->_quote($table);
334 }
c2b7c5dc 335
6f4ddea1 336 local $self->{rownum_hack_count} = 1
337 if (defined $rest[0] && $self->{limit_dialect} eq 'RowNum');
338 @rest = (-1) unless defined $rest[0];
e8fcf76f 339 croak "LIMIT 0 Does Not Compute" if $rest[0] == 0;
6f4ddea1 340 # and anyway, SQL::Abstract::Limit will cause a barf if we don't first
db56cf3d 341 my ($sql, @where_bind) = $self->SUPER::select(
6f4ddea1 342 $table, $self->_recurse_fields($fields), $where, $order, @rest
343 );
ec7cfd36 344 if (my $for = delete $self->{_dbic_rs_attrs}{for}) {
345 $sql .= " $for_syntax->{$for}" if $for_syntax->{$for};
346 }
347
1cbd3034 348 return wantarray ? ($sql, @{$self->{from_bind}}, @where_bind, @{$self->{having_bind}}, @{$self->{order_bind}} ) : $sql;
6f4ddea1 349}
350
998373c2 351# Quotes table names, and handles default inserts
6f4ddea1 352sub insert {
353 my $self = shift;
354 my $table = shift;
c2b7c5dc 355 $table = $self->_quote($table);
7a72e5a5 356
357 # SQLA will emit INSERT INTO $table ( ) VALUES ( )
358 # which is sadly understood only by MySQL. Change default behavior here,
359 # until SQLA2 comes with proper dialect support
360 if (! $_[0] or (ref $_[0] eq 'HASH' and !keys %{$_[0]} ) ) {
361 return "INSERT INTO ${table} DEFAULT VALUES"
362 }
363
6f4ddea1 364 $self->SUPER::insert($table, @_);
365}
366
998373c2 367# Just quotes table names.
6f4ddea1 368sub update {
369 my $self = shift;
370 my $table = shift;
c2b7c5dc 371 $table = $self->_quote($table);
6f4ddea1 372 $self->SUPER::update($table, @_);
373}
374
998373c2 375# Just quotes table names.
6f4ddea1 376sub delete {
377 my $self = shift;
378 my $table = shift;
c2b7c5dc 379 $table = $self->_quote($table);
6f4ddea1 380 $self->SUPER::delete($table, @_);
381}
382
383sub _emulate_limit {
384 my $self = shift;
385 if ($_[3] == -1) {
386 return $_[1].$self->_order_by($_[2]);
387 } else {
388 return $self->SUPER::_emulate_limit(@_);
389 }
390}
391
392sub _recurse_fields {
393 my ($self, $fields, $params) = @_;
394 my $ref = ref $fields;
395 return $self->_quote($fields) unless $ref;
396 return $$fields if $ref eq 'SCALAR';
397
398 if ($ref eq 'ARRAY') {
399 return join(', ', map {
400 $self->_recurse_fields($_)
401 .(exists $self->{rownum_hack_count} && !($params && $params->{no_rownum_hack})
402 ? ' AS col'.$self->{rownum_hack_count}++
403 : '')
404 } @$fields);
83e09b5b 405 }
406 elsif ($ref eq 'HASH') {
407 my %hash = %$fields;
408 my ($select, $as);
409
410 if ($hash{-select}) {
411 $select = $self->_recurse_fields (delete $hash{-select});
412 $as = $self->_quote (delete $hash{-as});
413 }
414 else {
415 my ($func, $args) = each %hash;
416 delete $hash{$func};
417
418 if (lc ($func) eq 'distinct' && ref $args eq 'ARRAY' && @$args > 1) {
419 croak (
420 'The select => { distinct => ... } syntax is not supported for multiple columns.'
421 .' Instead please use { group_by => [ qw/' . (join ' ', @$args) . '/ ] }'
422 .' or { select => [ qw/' . (join ' ', @$args) . '/ ], distinct => 1 }'
423 );
db56cf3d 424 }
83e09b5b 425 $select = sprintf ('%s( %s )',
426 $self->_sqlcase($func),
427 $self->_recurse_fields($args)
428 );
6f4ddea1 429 }
83e09b5b 430
431 # there should be nothing left
432 if (keys %hash) {
433 croak "Malformed select argument - too many keys in hash: " . join (',', keys %$fields );
6f4ddea1 434 }
83e09b5b 435
436 $select .= " AS $as" if $as;
437 return $select;
6f4ddea1 438 }
439 # Is the second check absolutely necessary?
440 elsif ( $ref eq 'REF' and ref($$fields) eq 'ARRAY' ) {
db56cf3d 441 return $self->_fold_sqlbind( $fields );
6f4ddea1 442 }
443 else {
e8fcf76f 444 croak($ref . qq{ unexpected in _recurse_fields()})
6f4ddea1 445 }
446}
447
448sub _order_by {
1cbd3034 449 my ($self, $arg) = @_;
15827712 450
1cbd3034 451 if (ref $arg eq 'HASH' and keys %$arg and not grep { $_ =~ /^-(?:desc|asc)/i } keys %$arg ) {
452
453 my $ret = '';
454
83e09b5b 455 if (my $g = $self->_recurse_fields($arg->{group_by}, { no_rownum_hack => 1 }) ) {
456 $ret = $self->_sqlcase(' group by ') . $g;
6f4ddea1 457 }
15827712 458
1cbd3034 459 if (defined $arg->{having}) {
460 my ($frag, @bind) = $self->_recurse_where($arg->{having});
461 push(@{$self->{having_bind}}, @bind);
6f4ddea1 462 $ret .= $self->_sqlcase(' having ').$frag;
463 }
15827712 464
1cbd3034 465 if (defined $arg->{order_by}) {
466 my ($frag, @bind) = $self->SUPER::_order_by($arg->{order_by});
467 push(@{$self->{order_bind}}, @bind);
468 $ret .= $frag;
6f4ddea1 469 }
15827712 470
1cbd3034 471 return $ret;
fde3719a 472 }
1cbd3034 473 else {
474 my ($sql, @bind) = $self->SUPER::_order_by ($arg);
475 push(@{$self->{order_bind}}, @bind);
476 return $sql;
fd4cb60a 477 }
6f4ddea1 478}
479
1cbd3034 480sub _order_directions {
fd4cb60a 481 my ($self, $order) = @_;
15827712 482
1cbd3034 483 # strip bind values - none of the current _order_directions users support them
484 return $self->SUPER::_order_directions( [ map
485 { ref $_ ? $_->[0] : $_ }
486 $self->_order_by_chunks ($order)
487 ]);
fd4cb60a 488}
489
6f4ddea1 490sub _table {
491 my ($self, $from) = @_;
492 if (ref $from eq 'ARRAY') {
493 return $self->_recurse_from(@$from);
494 } elsif (ref $from eq 'HASH') {
495 return $self->_make_as($from);
496 } else {
497 return $from; # would love to quote here but _table ends up getting called
498 # twice during an ->select without a limit clause due to
499 # the way S::A::Limit->select works. should maybe consider
500 # bypassing this and doing S::A::select($self, ...) in
501 # our select method above. meantime, quoting shims have
502 # been added to select/insert/update/delete here
503 }
504}
505
506sub _recurse_from {
507 my ($self, $from, @join) = @_;
508 my @sqlf;
509 push(@sqlf, $self->_make_as($from));
510 foreach my $j (@join) {
511 my ($to, $on) = @$j;
512
513 # check whether a join type exists
514 my $join_clause = '';
515 my $to_jt = ref($to) eq 'ARRAY' ? $to->[0] : $to;
516 if (ref($to_jt) eq 'HASH' and exists($to_jt->{-join_type})) {
517 $join_clause = ' '.uc($to_jt->{-join_type}).' JOIN ';
518 } else {
519 $join_clause = ' JOIN ';
520 }
521 push(@sqlf, $join_clause);
522
523 if (ref $to eq 'ARRAY') {
524 push(@sqlf, '(', $self->_recurse_from(@$to), ')');
525 } else {
526 push(@sqlf, $self->_make_as($to));
527 }
528 push(@sqlf, ' ON ', $self->_join_condition($on));
529 }
530 return join('', @sqlf);
531}
532
db56cf3d 533sub _fold_sqlbind {
534 my ($self, $sqlbind) = @_;
69989ea9 535
536 my @sqlbind = @$$sqlbind; # copy
537 my $sql = shift @sqlbind;
538 push @{$self->{from_bind}}, @sqlbind;
539
db56cf3d 540 return $sql;
6f4ddea1 541}
542
543sub _make_as {
544 my ($self, $from) = @_;
db56cf3d 545 return join(' ', map { (ref $_ eq 'SCALAR' ? $$_
546 : ref $_ eq 'REF' ? $self->_fold_sqlbind($_)
547 : $self->_quote($_))
6f4ddea1 548 } reverse each %{$self->_skip_options($from)});
549}
550
551sub _skip_options {
552 my ($self, $hash) = @_;
553 my $clean_hash = {};
554 $clean_hash->{$_} = $hash->{$_}
555 for grep {!/^-/} keys %$hash;
556 return $clean_hash;
557}
558
559sub _join_condition {
560 my ($self, $cond) = @_;
561 if (ref $cond eq 'HASH') {
562 my %j;
563 for (keys %$cond) {
564 my $v = $cond->{$_};
565 if (ref $v) {
e8fcf76f 566 croak (ref($v) . qq{ reference arguments are not supported in JOINS - try using \"..." instead'})
6f4ddea1 567 if ref($v) ne 'SCALAR';
568 $j{$_} = $v;
569 }
570 else {
571 my $x = '= '.$self->_quote($v); $j{$_} = \$x;
572 }
573 };
574 return scalar($self->_recurse_where(\%j));
575 } elsif (ref $cond eq 'ARRAY') {
576 return join(' OR ', map { $self->_join_condition($_) } @$cond);
577 } else {
578 die "Can't handle this yet!";
579 }
580}
581
582sub _quote {
583 my ($self, $label) = @_;
584 return '' unless defined $label;
c2b7c5dc 585 return $$label if ref($label) eq 'SCALAR';
6f4ddea1 586 return "*" if $label eq '*';
587 return $label unless $self->{quote_char};
588 if(ref $self->{quote_char} eq "ARRAY"){
589 return $self->{quote_char}->[0] . $label . $self->{quote_char}->[1]
590 if !defined $self->{name_sep};
591 my $sep = $self->{name_sep};
592 return join($self->{name_sep},
593 map { $self->{quote_char}->[0] . $_ . $self->{quote_char}->[1] }
594 split(/\Q$sep\E/,$label));
595 }
596 return $self->SUPER::_quote($label);
597}
598
599sub limit_dialect {
600 my $self = shift;
601 $self->{limit_dialect} = shift if @_;
602 return $self->{limit_dialect};
603}
604
998373c2 605# Set to an array-ref to specify separate left and right quotes for table names.
606# A single scalar is equivalen to [ $char, $char ]
6f4ddea1 607sub quote_char {
608 my $self = shift;
609 $self->{quote_char} = shift if @_;
610 return $self->{quote_char};
611}
612
998373c2 613# Character separating quoted table names.
6f4ddea1 614sub name_sep {
615 my $self = shift;
616 $self->{name_sep} = shift if @_;
617 return $self->{name_sep};
618}
619
6201;