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=583045c45ace9e924699e5ea9434bb34b2a72c58;hpb=a4812caaab21149be7c3c65ad6c0388046430130;p=dbsrgits%2FDBIx-Class.git

diff --git a/lib/DBIx/Class/Storage/DBIHacks.pm b/lib/DBIx/Class/Storage/DBIHacks.pm
index 583045c..3efd488 100644
--- a/lib/DBIx/Class/Storage/DBIHacks.pm
+++ b/lib/DBIx/Class/Storage/DBIHacks.pm
@@ -4,7 +4,7 @@ package   #hide from PAUSE
 #
 # 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;
@@ -15,6 +15,7 @@ use mro 'c3';
 
 use List::Util 'first';
 use Scalar::Util 'blessed';
+use Sub::Name 'subname';
 use namespace::clean;
 
 #
@@ -60,7 +61,7 @@ sub _prune_unused_joins {
 
 #
 # 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) = @_;
@@ -76,18 +77,8 @@ 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_selector_range _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
@@ -515,7 +506,11 @@ sub _resolve_column_info {
       },
       -result_source => $rsrc,
       -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;
@@ -568,7 +563,7 @@ sub _inner_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 $sw_idx = { map { (values %$_), 1 } @$switch_branch }; #there's one k/v per join-path
 
@@ -591,64 +586,59 @@ sub _inner_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_from_array {
-  my ($self, $where) = @_;
-  my @cond;
-  for (my $i = 0; $i < @$where; $i++) {
-    my $entry = $where->[$i];
-    my $hash;
-    my $ref = ref $entry;
-    if ($ref eq 'HASH' or $ref eq 'ARRAY') {
-      $hash = $self->_strip_cond_qualifiers($entry);
-    }
-    elsif (! $ref) {
-      $entry =~ /([^.]+)$/;
-      $hash->{$1} = $where->[++$i];
-    }
-    push @cond, $hash;
-  }
-  return \@cond;
-}
-
-sub _strip_cond_qualifiers {
-  my ($self, $where) = @_;
-
-  my $cond = {};
-
-  # No-op. No condition, we're updating/deleting everything
-  return $cond unless $where;
-
-  if (ref $where eq 'ARRAY') {
-    $cond = $self->_strip_cond_qualifiers_from_array($where);
-  }
-  elsif (ref $where eq 'HASH') {
-    if ( (keys %$where) == 1 && ( (keys %{$where})[0] eq '-and' )) {
-      $cond->{-and} =
-        $self->_strip_cond_qualifiers_from_array($where->{-and});
-    }
-    else {
-      foreach my $key (keys %$where) {
-        if ($key eq '-or' && ref $where->{$key} eq 'ARRAY') {
-          $cond->{$key} = $self->_strip_cond_qualifiers($where->{$key});
+# yet another atrocity: attempt to extract all columns from a
+# where condition by hooking _quote
+sub _extract_condition_columns {
+  my ($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 {
-          $key =~ /([^.]+)$/;
-          $cond->{$1} = $where->{$key};
+          $self->{_captured_idents}{$ident}++;
         }
-      }
+        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 {
-    return undef;
-  }
 
-  return $cond;
+    $smic_class->new();
+  };
+
+  $sql_maker->_recurse_where($cond);
+
+  return [ sort keys %{$sql_maker->_get_captured_idents} ];
 }
 
 sub _extract_order_criteria {
@@ -680,4 +670,62 @@ sub _extract_order_criteria {
   }
 }
 
+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($where)} :(),
+  ]);
+
+  return undef unless keys %$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;