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 720d12f..3171dd4 100644 (file)
--- a/lib/ID3FS/Path/Node.pm
+++ b/lib/ID3FS/Path/Node.pm
@@ -98,29 +98,27 @@ sub to_sql
     my $op=$self->name();
     if(defined($op))
     {
-       my $left_is_not =($left  && $left->name()  && $left->name()  eq "NOT");
-       my $right_is_not=($right && $right->name() && $right->name() eq "NOT");
        my $join=undef;
-       # if we are ANDing, add an inner join
+       # if we are ANDing add an inner join
        # also if we are NOTing, but we are looking for a tag *value*
        if($op eq "AND")
        {
            # 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
-           $join= "INNER" unless($right_is_not);
+           $join= "INNER" unless($right && $right->name() && $right->name() eq "NOT");
        }
        elsif($op eq "NOT")
        {
            $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
-           $join = ($hasvals ? "INNER" : "LEFT") unless($right_is_not);
+           $join = ($hasvals ? "INNER" : "LEFT");
        }
        elsif($op eq "OR")
        {
-           # if left child is a NOT, we need an extra (inner) join
-           # unless right child is also a NOT
-           $join="INNER" if($left_is_not && ! $right_is_not)
+           # 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)
        {
@@ -150,4 +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;