X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDBIx%2FClass%2FStorage%2FDBIHacks.pm;h=d8abdc28a2632c884d44b2cc0812573b3e458b85;hb=964a3c7149c1baeda0d4379305f775446abe870f;hp=61331fe19c47ca2314acb229f348ee824743f551;hpb=c443438f238cca5549967e4448aa45aeef9d6965;p=dbsrgits%2FDBIx-Class.git

diff --git a/lib/DBIx/Class/Storage/DBIHacks.pm b/lib/DBIx/Class/Storage/DBIHacks.pm
index 61331fe..d8abdc2 100644
--- a/lib/DBIx/Class/Storage/DBIHacks.pm
+++ b/lib/DBIx/Class/Storage/DBIHacks.pm
@@ -63,93 +63,30 @@ 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;
-        }
-      }
+  # scan the from spec against different attributes, and see which joins are needed
+  # in what role
+  my $inner_aliastypes =
+    $self->_resolve_aliases_from_select_args( $from, $where, $inner_select, $inner_attrs );
+  my $outer_aliastypes =
+    $self->_resolve_aliases_from_select_args( $from, $where, $outer_select, $outer_attrs );
 
-      if ($non_prefetch_select_sql =~ $seen_re) {
-          $select_aliases->{$alias} = 1;
-      }
 
-      if ($prefetch_select_sql =~ $seen_re) {
-          $prefetch_aliases->{$alias} = 1;
-      }
 
-    }
-  }
-
-  # 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)
-    );
-  }
+  # 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] ];
 
-  # 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} || [] });
-    }
-  }
 
   # construct the inner $from for the subquery
-  my %inner_joins = (map { %{$_ || {}} } ($restrict_aliases, $select_aliases) );
+  my %inner_joins = (map { %$_ } (values %$inner_aliastypes) );
   my @inner_from;
   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
   unless ($inner_attrs->{group_by}) {
@@ -213,10 +150,10 @@ sub _adjust_select_args_for_complex_prefetch {
   while (my $j = shift @$from) {
     my $alias = $j->[0]{-alias};
 
-    if ($select_aliases->{$alias} || $prefetch_aliases->{$alias}) {
+    if ($outer_aliastypes->{select}{$alias}) {
       push @outer_from, $j;
     }
-    elsif ($restrict_aliases->{$alias}) {
+    elsif ($outer_aliastypes->{restrict}{$alias}) {
       push @outer_from, $j;
 
       # FIXME - this should be obviated by SQLA2, as I'll be able to 
@@ -250,6 +187,83 @@ sub _adjust_select_args_for_complex_prefetch {
   return (\@outer_from, $outer_select, $where, $outer_attrs);
 }
 
+# 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 an unqualified column, which in
+# turn will result in a vocal exception. Qualifying the column will
+# invariably solve the problem.
+sub _resolve_aliases_from_select_args {
+  my ( $self, $from, $where, $select, $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 $alias_list;
+  my @from = @$from; # if I don't copy weird shit happens
+  for my $j (@from) {
+    $j = $j->[0] if ref $j eq 'ARRAY';
+    $alias_list->{$j->{-alias}} = $j;
+  }
+
+  # set up a botched SQLA
+  my $sql_maker = $self->sql_maker;
+  my $sep = quotemeta ($self->_sql_maker_opts->{name_sep} || '.');
+  local $sql_maker->{quote_char}; # so that we can regex away
+
+
+  my $select_sql = $sql_maker->_recurse_fields ($select);
+  my $where_sql = $sql_maker->where ($where);
+  my $group_by_sql = $sql_maker->_order_by({
+    map { $_ => $attrs->{$_} } qw/group_by having/
+  });
+  my @order_by_chunks = (map
+    { ref $_ ? $_->[0] : $_ }
+    $sql_maker->_order_by_chunks ($attrs->{order_by})
+  );
+
+  # match every alias to the sql chunks above
+  for my $alias (keys %$alias_list) {
+    my $al_re = qr/\b $alias $sep/x;
+
+    for my $piece ($where_sql, $group_by_sql) {
+      $aliases_by_type->{restrict}{$alias} = 1 if ($piece =~ $al_re);
+    }
+
+    for my $piece ($select_sql, @order_by_chunks ) {
+      $aliases_by_type->{select}{$alias} = 1 if ($piece =~ $al_re);
+    }
+  }
+
+  # 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;
+    $aliases_by_type->{restrict}{$alias} = 1 if (
+      (not $j->{-join_type})
+        or
+      ($j->{-join_type} !~ /^left (?: \s+ outer)? $/xi)
+    );
+  }
+
+  # mark all join parents as mentioned
+  # (e.g.  join => { cds => 'tracks' } - tracks will need to bring cds too )
+  for my $type (keys %$aliases_by_type) {
+    for my $alias (keys %{$aliases_by_type->{$type}}) {
+      $aliases_by_type->{$type}{$_} = 1
+        for (@{ $alias_list->{$alias}{-join_path} || [] });
+    }
+  }
+
+  return $aliases_by_type;
+}
+
 sub _resolve_ident_sources {
   my ($self, $ident) = @_;
 
@@ -288,16 +302,16 @@ 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 $qsep = quotemeta $sep;
 
-  my (%return, %seen_cols);
+  my (%return, %seen_cols, @auto_colnames);
 
   # compile a global list of column names, to be able to properly
   # disambiguate unqualified column names (if at all possible)
@@ -305,12 +319,18 @@ sub _resolve_column_info {
     my $rsrc = $alias2src->{$alias};
     for my $colname ($rsrc->columns) {
       push @{$seen_cols{$colname}}, $alias;
+      push @auto_colnames, "$alias$sep$colname" unless $colnames;
     }
   }
 
+  $colnames ||= [
+    @auto_colnames,
+    grep { @{$seen_cols{$_}} == 1 } (keys %seen_cols),
+  ];
+
   COLUMN:
   foreach my $col (@$colnames) {
-    my ($alias, $colname) = $col =~ m/^ (?: ([^$sep]+) $sep)? (.+) $/x;
+    my ($alias, $colname) = $col =~ m/^ (?: ([^$qsep]+) $qsep)? (.+) $/x;
 
     unless ($alias) {
       # see if the column was seen exactly once (so we know which rsrc it came from)