X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDBIx%2FClass%2FStorage%2FDBI.pm;h=6f66848347eec7be5921e1a9a8c4248c43bc789a;hb=212cc5c25c31b2ec3ff4b4e20283321617db79e6;hp=6af9431ce7d9fd0ba179d6e46dd8ea5edc25d626;hpb=d7b48618e1b509c0c69b0d6e39acb007e8ea68de;p=dbsrgits%2FDBIx-Class.git

diff --git a/lib/DBIx/Class/Storage/DBI.pm b/lib/DBIx/Class/Storage/DBI.pm
index 6af9431..6f66848 100644
--- a/lib/DBIx/Class/Storage/DBI.pm
+++ b/lib/DBIx/Class/Storage/DBI.pm
@@ -1,10 +1,12 @@
 package DBIx::Class::Storage::DBI;
 # -*- mode: cperl; cperl-indent-level: 2 -*-
 
-use base 'DBIx::Class::Storage';
-
 use strict;
 use warnings;
+
+use base 'DBIx::Class::Storage';
+use mro 'c3';
+
 use Carp::Clan qw/^DBIx::Class/;
 use DBI;
 use DBIx::Class::Storage::DBI::Cursor;
@@ -669,12 +671,20 @@ sub connected {
           $self->_verify_pid;
           return 0 if !$self->_dbh;
       }
-      return ($dbh->FETCH('Active') && $dbh->ping);
+      return ($dbh->FETCH('Active') && $self->_ping);
   }
 
   return 0;
 }
 
+sub _ping {
+  my $self = shift;
+
+  my $dbh = $self->_dbh or return 0;
+
+  return $dbh->ping;
+}
+
 # handle pid changes correctly
 #  NOTE: assumes $self->_dbh is a valid $dbh
 sub _verify_pid {
@@ -1368,16 +1378,20 @@ sub _select_args_to_query {
 sub _select_args {
   my ($self, $ident, $select, $where, $attrs) = @_;
 
+  my ($alias2source, $rs_alias) = $self->_resolve_ident_sources ($ident);
+
   my $sql_maker = $self->sql_maker;
   $sql_maker->{_dbic_rs_attrs} = {
     %$attrs,
     select => $select,
     from => $ident,
     where => $where,
+    $rs_alias
+      ? ( _source_handle => $alias2source->{$rs_alias}->handle )
+      : ()
+    ,
   };
 
-  my ($alias2source, $root_alias) = $self->_resolve_ident_sources ($ident);
-
   # calculate bind_attrs before possible $ident mangling
   my $bind_attrs = {};
   for my $alias (keys %$alias2source) {
@@ -1388,28 +1402,41 @@ sub _select_args {
       $bind_attrs->{$fqcn} = $bindtypes->{$col} if $bindtypes->{$col};
 
       # so that unqualified searches can be bound too
-      $bind_attrs->{$col} = $bind_attrs->{$fqcn} if $alias eq $root_alias;
+      $bind_attrs->{$col} = $bind_attrs->{$fqcn} if $alias eq $rs_alias;
     }
   }
 
-  my @limit;
-  if ($attrs->{software_limit} ||
-      $sql_maker->_default_limit_syntax eq "GenericSubQ") {
-        $attrs->{software_limit} = 1;
-  } else {
+  # adjust limits
+  if (
+    $attrs->{software_limit}
+      ||
+    $sql_maker->_default_limit_syntax eq "GenericSubQ"
+  ) {
+    $attrs->{software_limit} = 1;
+  }
+  else {
     $self->throw_exception("rows attribute must be positive if present")
       if (defined($attrs->{rows}) && !($attrs->{rows} > 0));
 
     # MySQL actually recommends this approach.  I cringe.
     $attrs->{rows} = 2**48 if not defined $attrs->{rows} and defined $attrs->{offset};
+  }
 
-    if ($attrs->{rows} && keys %{$attrs->{collapse}}) {
-      ($ident, $select, $where, $attrs)
-        = $self->_adjust_select_args_for_limited_prefetch ($ident, $select, $where, $attrs);
-    }
-    else {
-      push @limit, $attrs->{rows}, $attrs->{offset};
-    }
+  my @limit;
+
+  # see if we need to tear the prefetch apart (either limited has_many or grouped prefetch)
+  # otherwise delegate the limiting to the storage, unless software limit was requested
+  if (
+    ( $attrs->{rows} && keys %{$attrs->{collapse}} )
+       ||
+    ( $attrs->{group_by} && @{$attrs->{group_by}} &&
+      $attrs->{prefetch_select} && @{$attrs->{prefetch_select}} )
+  ) {
+    ($ident, $select, $where, $attrs)
+      = $self->_adjust_select_args_for_complex_prefetch ($ident, $select, $where, $attrs);
+  }
+  elsif (! $attrs->{software_limit} ) {
+    push @limit, $attrs->{rows}, $attrs->{offset};
   }
 
 ###
@@ -1424,45 +1451,61 @@ sub _select_args {
 
   my $order = { map
     { $attrs->{$_} ? ( $_ => $attrs->{$_} ) : ()  }
-    (qw/order_by group_by having _virtual_order_by/ )
+    (qw/order_by group_by having/ )
   };
 
-
   return ('select', $attrs->{bind}, $ident, $bind_attrs, $select, $where, $order, @limit);
 }
 
-sub _adjust_select_args_for_limited_prefetch {
+#
+# This is the code producing joined subqueries like:
+# SELECT me.*, other.* FROM ( SELECT me.* FROM ... ) JOIN other ON ... 
+#
+sub _adjust_select_args_for_complex_prefetch {
   my ($self, $from, $select, $where, $attrs) = @_;
 
-  if ($attrs->{group_by} && @{$attrs->{group_by}}) {
-    $self->throw_exception ('has_many prefetch with limit (rows/offset) is not supported on grouped resultsets');
-  }
-
-  $self->throw_exception ('has_many prefetch with limit (rows/offset) is not supported on resultsets with a custom from attribute')
+  $self->throw_exception ('Complex prefetches are not supported on resultsets with a custom from attribute')
     if (ref $from ne 'ARRAY');
 
+  # copies for mangling
+  $from = [ @$from ];
+  $select = [ @$select ];
+  $attrs = { %$attrs };
 
   # separate attributes
   my $sub_attrs = { %$attrs };
-  delete $attrs->{$_} for qw/where bind rows offset/;
-  delete $sub_attrs->{$_} for qw/for collapse select as order_by/;
+  delete $attrs->{$_} for qw/where bind rows offset group_by having/;
+  delete $sub_attrs->{$_} for qw/for collapse prefetch_select _collapse_order_by select as/;
 
   my $alias = $attrs->{alias};
+  my $sql_maker = $self->sql_maker;
 
-  # create subquery select list
-  my $sub_select = [ grep { $_ =~ /^$alias\./ } @{$attrs->{select}} ];
+  # create subquery select list - loop only over primary columns
+  my $sub_select = [];
+  for my $i (0 .. @{$attrs->{select}} - @{$attrs->{prefetch_select}} - 1) {
+    my $sel = $attrs->{select}[$i];
+
+    # alias any functions to the dbic-side 'as' label
+    # adjust the outer select accordingly
+    if (ref $sel eq 'HASH' && !$sel->{-select}) {
+      $sel = { -select => $sel, -as => $attrs->{as}[$i] };
+      $select->[$i] = join ('.', $attrs->{alias}, $attrs->{as}[$i]);
+    }
+
+    push @$sub_select, $sel;
+  }
 
   # bring over all non-collapse-induced order_by into the inner query (if any)
   # the outer one will have to keep them all
+  delete $sub_attrs->{order_by};
   if (my $ord_cnt = @{$attrs->{order_by}} - @{$attrs->{_collapse_order_by}} ) {
     $sub_attrs->{order_by} = [
-      @{$attrs->{order_by}}[ 0 .. ($#{$attrs->{order_by}} - $ord_cnt - 1) ]
+      @{$attrs->{order_by}}[ 0 .. $ord_cnt - 1]
     ];
   }
 
   # mangle {from}
-  $from = [ @$from ];
-  my $select_root = shift @$from;
+  my $join_root = shift @$from;
   my @outer_from = @$from;
 
   my %inner_joins;
@@ -1472,7 +1515,7 @@ sub _adjust_select_args_for_limited_prefetch {
   # so always include it in the inner join, and also shift away
   # from the outer stack, so that the two datasets actually do
   # meet
-  if ($select_root->{-alias} ne $alias) {
+  if ($join_root->{-alias} ne $alias) {
     $inner_joins{$alias} = 1;
 
     while (@outer_from && $outer_from[0][0]{-alias} ne $alias) {
@@ -1493,7 +1536,7 @@ sub _adjust_select_args_for_limited_prefetch {
   # away _any_ branches of the join tree that are:
   # 1) not mentioned in the condition/order
   # 2) left-join leaves (or left-join leaf chains)
-  # Most of the join ocnditions will not satisfy this, but for real
+  # Most of the join conditions will not satisfy this, but for real
   # complex queries some might, and we might make some RDBMS happy.
   #
   #
@@ -1503,7 +1546,6 @@ sub _adjust_select_args_for_limited_prefetch {
   # It may not be very efficient, but it's a reasonable stop-gap
   {
     # produce stuff unquoted, so it can be scanned
-    my $sql_maker = $self->sql_maker;
     local $sql_maker->{quote_char};
 
     my @order_by = (map
@@ -1543,20 +1585,19 @@ sub _adjust_select_args_for_limited_prefetch {
   }
 
   # construct the inner $from for the subquery
-  my $inner_from = [ $select_root ];
+  my $inner_from = [ $join_root ];
   for my $j (@$from) {
     push @$inner_from, $j if $inner_joins{$j->[0]{-alias}};
   }
 
   # 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
-
   for my $alias (keys %inner_joins) {
 
     # the dot comes from some weirdness in collapse
     # remove after the rewrite
     if ($attrs->{collapse}{".$alias"}) {
-      $sub_attrs->{group_by} = $sub_select;
+      $sub_attrs->{group_by} ||= $sub_select;
       last;
     }
   }
@@ -1572,7 +1613,7 @@ sub _adjust_select_args_for_limited_prefetch {
   # put it in the new {from}
   unshift @outer_from, {
     -alias => $alias,
-    -source_handle => $select_root->{-source_handle},
+    -source_handle => $join_root->{-source_handle},
     $alias => $subq,
   };
 
@@ -1590,14 +1631,14 @@ sub _resolve_ident_sources {
   my ($self, $ident) = @_;
 
   my $alias2source = {};
-  my $root_alias;
+  my $rs_alias;
 
   # 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") ) {
     # this is compat mode for insert/update/delete which do not deal with aliases
     $alias2source->{me} = $ident;
-    $root_alias = 'me';
+    $rs_alias = 'me';
   }
   elsif (ref $ident eq 'ARRAY') {
 
@@ -1605,7 +1646,7 @@ sub _resolve_ident_sources {
       my $tabinfo;
       if (ref $_ eq 'HASH') {
         $tabinfo = $_;
-        $root_alias = $tabinfo->{-alias};
+        $rs_alias = $tabinfo->{-alias};
       }
       if (ref $_ eq 'ARRAY' and ref $_->[0] eq 'HASH') {
         $tabinfo = $_->[0];
@@ -1616,7 +1657,7 @@ sub _resolve_ident_sources {
     }
   }
 
-  return ($alias2source, $root_alias);
+  return ($alias2source, $rs_alias);
 }
 
 # Takes $ident, \@column_names