From: Matt S Trout <mst@shadowcat.co.uk>
Date: Thu, 23 Aug 2012 18:26:58 +0000 (+0000)
Subject: nuke old attempt at generic subquery
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=633b6f7155acb219fed0e82de1e5d93ffe355251;p=dbsrgits%2FData-Query.git

nuke old attempt at generic subquery
---

diff --git a/lib/Data/Query/Renderer/SQL/Slice/GenericSubQ.pm b/lib/Data/Query/Renderer/SQL/Slice/GenericSubQ.pm
deleted file mode 100644
index f912f61..0000000
--- a/lib/Data/Query/Renderer/SQL/Slice/GenericSubQ.pm
+++ /dev/null
@@ -1,214 +0,0 @@
-package Data::Query::Renderer::SQL::Slice::GenericSubQ;
-
-use Data::Query::Constants qw(
-  DQ_SELECT DQ_ALIAS DQ_IDENTIFIER DQ_ORDER DQ_SLICE
-  DQ_WHERE DQ_OPERATOR
-);
-use Moo::Role;
-
-sub _render_slice {
-  my ($self, $dq) = @_;
-  unless ($dq->{order_is_stable}) {
-    die "GenericSubQ limit style requires a stable order";
-  }
-  die "Slice's inner is not a Select"
-    unless (my $orig_select = $dq->{from})->{type} eq DQ_SELECT;
-  my %alias_map;
-  my $gensym_count;
-  my (@inside_select_list, @outside_select_list);
-  my $default_inside_alias;
-  SELECT: foreach my $s (@{$orig_select->{select}}) {
-    my $name;
-    if ($s->{type} eq DQ_ALIAS) {
-      $name = $s->{to};
-      $s = $s->{from};
-    }
-    my $key;
-    if ($s->{type} eq DQ_IDENTIFIER) {
-      if (!$name and @{$s->{elements}} == 2) {
-        $default_inside_alias ||= $s->{elements}[0];
-        if ($s->{elements}[0] eq $default_inside_alias) {
-          $alias_map{join('.',@{$s->{elements}})} = $s;
-          push @inside_select_list, $s;
-          push @outside_select_list, $s;
-          next SELECT;
-        }
-      }
-      $name ||= join('__', @{$s->{elements}});
-      $key = join('.', @{$s->{elements}});
-    } else {
-      die "XXX not implemented yet" unless $name;
-      $key = "$s";
-    }
-    $name ||= sprintf("GENSYM__%03i",++$gensym_count);
-    push @inside_select_list, +{
-      type => DQ_ALIAS,
-      from => $s,
-      to => $name,
-    };
-    push @outside_select_list, $alias_map{$key} = +{
-      type => DQ_IDENTIFIER,
-      elements => [ $name ]
-    };
-  }
-  my $order = $orig_select->{from};
-  my $order_gensym_count;
-  die "Slice's Select not followed by Order but order_is_stable set"
-    unless $order->{type} eq DQ_ORDER;
-  my (@order_nodes, %order_map);
-  while ($order->{type} eq DQ_ORDER) {
-    my $by = $order->{by};
-    if ($by->{type} eq DQ_IDENTIFIER) {
-      $default_inside_alias ||= $by->{elements}[0]
-        if @{$by->{elements}} == 2;
-      $order_map{$by}
-        = $alias_map{join('.', @{$by->{elements}})}
-          ||= do {
-                if (
-                  @{$by->{elements}} == 2
-                  and $by->{elements}[0] eq $default_inside_alias
-                ) {
-                  $by;
-                } else {
-                  my $name = sprintf("ORDER__BY__%03i",++$order_gensym_count);
-                  push @inside_select_list, +{
-                    type => DQ_ALIAS,
-                    from => $by,
-                    to => $name
-                  };
-                  +{
-                    type => DQ_IDENTIFIER,
-                    elements => [ $name ],
-                  };
-                }
-              };
-    } else {
-      die "XXX not implemented yet";
-    }
-    push @order_nodes, $order;
-    $order = $order->{from};
-  }
-  my $inside_select = +{
-    type => DQ_SELECT,
-    select => \@inside_select_list,
-    from => $order,
-  };
-  $default_inside_alias ||= 'me';
-  my $bridge_from = +{
-    type => DQ_ALIAS,
-    to => $default_inside_alias,
-    from => $inside_select,
-  };
-  my $default_inside_from;
-  FIND_FROM: {
-    my @queue = $order;
-    my $cb_map = +{
-      DQ_ALIAS ,=> sub {
-        if ($_[0]->{to} eq $default_inside_alias) {
-          $default_inside_from = $_[0]->{from};
-          no warnings 'exiting';
-          last FIND_FROM;
-        }
-      }
-    };
-    # _scan_nodes from DBIHacks - maybe make this a sub somewhere?
-    while (my $node = shift @queue) {
-      if ($node->{type} and my $cb = $cb_map->{$node->{type}}) {
-        $cb->($node);
-      }
-      push @queue,
-        grep ref($_) eq 'HASH',
-          map +(ref($_) eq 'ARRAY' ? @$_ : $_),
-            @{$node}{grep !/\./, keys %$node};
-    }
-    die "Couldn't figure out where ${default_inside_alias} came from :(";
-  }
-  my $bridge_where = +{
-    type => DQ_WHERE,
-    from => $bridge_from,
-    where => {
-      type => DQ_OPERATOR,
-      operator => {
-        'SQL.Naive' => (
-          $dq->{offset}
-            ? 'BETWEEN'
-            : $order_nodes[0]{reverse} ? '>' : '<'
-        ),
-      },
-      args => [
-        {
-          type => DQ_SELECT,
-          select => [
-            {
-              type => DQ_OPERATOR,
-              operator => { 'SQL.Naive' => 'apply' },
-              args => [
-                {
-                  type => DQ_IDENTIFIER,
-                  elements => [ 'COUNT' ],
-                },
-                {
-                  type => DQ_IDENTIFIER,
-                  elements => [ '*' ],
-                }
-              ]
-            }
-          ],
-          from => {
-            type => DQ_WHERE,
-            from => {
-              type => DQ_ALIAS,
-              from => $default_inside_from,
-              to => 'rownum__emulation',
-            },
-            where => {
-              type => DQ_OPERATOR,
-              operator => {
-                'SQL.Naive' => $order_nodes[0]{reverse} ? '>' : '<'
-              },
-              args => [
-                map +{
-                  type => DQ_IDENTIFIER,
-                  elements => [
-                    $_,
-                    $order_nodes[0]{by}{elements}[-1],
-                  ]
-                }, 'rownum__emulation', $default_inside_alias,
-              ],
-            }
-          },
-        },
-        ($dq->{offset}
-           ? ($dq->{offset},
-               { %{$dq->{limit}},
-                 value => $dq->{offset}{value} + $dq->{limit}{value} - 1
-               }
-             )
-           : ($dq->{limit})
-        ),
-      ]
-    },
-  };
-  my $outside_order = $bridge_where;
-  $outside_order = +{
-    type => DQ_ORDER,
-    by => $order_map{$_->{by}},
-    reverse => $_->{reverse},
-    from => $outside_order
-  } for reverse @order_nodes;
-  my $outside_select = +{
-    type => DQ_SELECT,
-    select => (
-      $dq->{preserve_order}
-        ? [
-            @outside_select_list,
-            grep @{$_->{elements}} == 1, @order_map{map $_->{by}, @order_nodes}
-          ]
-        : \@outside_select_list,
-    ),
-    from => $outside_order,
-  };
-  return $self->_render($outside_select);
-}
-
-1;