more special-casing joins

[id3fs.git] / lib / ID3FS / Path / Node.pm

diff --git a/lib/ID3FS/Path/Node.pm b/lib/ID3FS/Path/Node.pm
index 774af3a..3171dd4 100644 (file)
--- a/lib/ID3FS/Path/Node.pm
+++ b/lib/ID3FS/Path/Node.pm
@@ -82,7 +82,7 @@ sub to_sql
        $str .= "t" . scalar(@joins) . ".id='" . $self->{id} . "'";
        if($not && !$hasvals)
        {
-           $str .= " AND fxt" . scalar(@joins) . ".files_id IS NULL";
+           $str = "(" . $str . " AND fxt" . scalar(@joins) . ".files_id IS NULL)";
        }
        return ($str, @outjoins);
     }
@@ -90,73 +90,48 @@ sub to_sql
     my $left=$self->left();
     my $right=$self->right();
     return ("", @outjoins) unless($left || $right);
+
     my ($leftstr, @leftjoins) = $left->to_sql($hasvals, $not, @joins) if($left);
     push(@joins, @leftjoins);
     push(@outjoins, @leftjoins);
+
     my $op=$self->name();
-    print "op: $op type: ", $self->type(), " not: $not\n";
     if(defined($op))
     {
-       # if we are ANDing, add an inner join
+       my $join=undef;
+       # if we are ANDing add an inner join
        # also if we are NOTing, but we are looking for a tag *value*
        if($op eq "AND")
        {
-           print "AND\n";
-           # hack - if right child is a NOT, we don't need extra join/brackets
+           # if right child is a NOT, we don't need extra join/brackets
            # NOT will do the same and we will end up with an extra one
-           unless($right && $right->name() && $right->name() eq "NOT")
-           {
-               push(@joins, "INNER");
-               push(@outjoins, "INNER");
-           }
+           $join= "INNER" unless($right && $right->name() && $right->name() eq "NOT");
        }
        elsif($op eq "NOT")
        {
-           print "NOT (was $not)\n";
            $not=1;
-           # as above - if right child is a NOT, we don't need extra join/brackets
-           # NOT will do the same and we will end up with an extra one
-           unless($right && $right->name() && $right->name() eq "NOT")
-           {
-               if($hasvals)
-               {
-                   push(@joins, "INNER");
-                   push(@outjoins, "INNER");
-               }
-               else
-               {
-                   push(@joins, "LEFT");
-                   push(@outjoins, "LEFT");
-               }
-           }
+           $join = ($hasvals ? "INNER" : "LEFT");
        }
        elsif($op eq "OR")
        {
-           print "OR\n";
-           # if left child is a NOT, we need an extra (inner) join
-           # unless right child is also a NOT
-           if(($left && $left->name() && $left->name() eq "NOT") &&
-              !($right && $right->name() && $right->name() eq "NOT"))
-           {
-               push(@joins, "INNER");
-               push(@outjoins, "INNER");
-           }
+           # if the rightmost part of the left sub-expression ends in
+           # NOT, then we need an extra join. This doesn't apply if
+           # (as above) the righthand expression is a NOT.
+           $join="INNER" if(($self->right_ends_in_not($left)) &&
+                            !($right && $right->name() && $right->name() eq "NOT"));
+       }
+       if($join)
+       {
+           push(@joins, $join);
+           push(@outjoins, $join);
        }
     }
     my ($rightstr, @rightjoins) = $right->to_sql($hasvals, $not, @joins) if($right);
     push(@outjoins, @rightjoins);
-#    print "LEFT (", scalar(@leftjoins), "): $leftstr\n";
-#    print "RIGHT (", scalar(@rightjoins), "): $rightstr\n";
-    $str=$leftstr;
+    $str = $leftstr;
     $str .= " $op " if($op && !$not);
     $str .= $rightstr;
-    if($op || ($left && $right))
-    {
-       $str="(" . $str . ")";
-    }
-#    print "STR: $str\n";
-#    my @all=(@joins, @rightjoins);
-#    print "JOINS: RETURN ", scalar(@outjoins), " ALL ", scalar(@all), "\n";
+    $str=("(" . $str . ")") if($op && $left && $right);
     return($str, @outjoins);
 }
 
@@ -173,4 +148,19 @@ sub used_tags
     return $self->id();
 }
 
+sub right_ends_in_not
+{
+    my($self, $node)=@_;
+    return 0 unless($node);
+    my $right=$node->right();
+    if($right && $right->type() == $TYPE_BOOL)
+    {
+       return $self->right_ends_in_not($right);
+    }
+    my $op=$node->name();
+    return 0 unless($op);
+    return 1 if($op eq "NOT");
+    return 0;
+}
+
 1;