From 91cc7c5ba55bf25572013dfa29112090003eccc2 Mon Sep 17 00:00:00 2001
From: Ian Beckwith <ianb@erislabs.net>
Date: Thu, 21 Oct 2010 22:50:13 +0100
Subject: [PATCH] preprocess elements, calculating joins

---
 lib/ID3FS/Path.pm      | 59 ++++++++++++++++++++++++++++++++++++++++++++++--
 lib/ID3FS/Path/Node.pm | 61 ++++++++++++--------------------------------------
 2 files changed, 71 insertions(+), 49 deletions(-)

diff --git a/lib/ID3FS/Path.pm b/lib/ID3FS/Path.pm
index c683101..855ea9e 100644
--- a/lib/ID3FS/Path.pm
+++ b/lib/ID3FS/Path.pm
@@ -356,11 +356,65 @@ sub parse
     {
 	pop @elements;
     }
+#    print "\nELEMENTS: ", join(' ', map { $_->name(); } @elements), "\n";
+    my @joins=$self->number_joins(@elements);
+#    @joins=qw(INNER) unless(@joins);
+    $self->{joins}=\@joins;
+#    print "AFTER: ", join(' ', map { $_->name() . "(" . $_->{table} . ")"; } @elements), "\n";
+#    print "JOINS: ", join(', ', @joins), "\n";
     # sort elements by precedence
     @elements=$self->sort_elements(@elements);
     $self->{tagtree}=$self->elements_to_tree(\@elements);
 }
 
+sub number_joins
+{
+    my($self, @elements)=@_;
+    my @joins=qw(INNER);
+    my $table=1;
+    my $lastop=undef;
+    return () unless(@elements);
+    while(my $thing=shift @elements)
+    {
+	if($thing->type() == $TYPE_BOOL)
+	{
+	    my $op=$thing->name();
+	    if($op eq "AND")
+	    {
+		$table++;
+		push(@joins, "INNER");
+	    }
+	    elsif($op eq "NOT")
+	    {
+		unless($lastop && $lastop eq "AND")
+		{
+		    push(@joins, "LEFT");
+		    $table++;
+		}
+	    }
+	    elsif($op eq "OR")
+	    {
+		if($lastop && $lastop eq "NOT")
+		{
+		    $table++;
+		    push(@joins, "INNER");
+		}
+	    }
+	    $lastop=$op;
+	}
+	else
+	{
+	    # skip tags with values
+	    if(@elements && $elements[0]->type() == $TYPE_TAG)
+	    {
+		$thing=shift(@elements);
+	    }
+	    $thing->table($table);
+	}
+    }
+    return @joins;
+}
+
 sub state
 {
     my($self, $newstate)=@_;
@@ -670,12 +724,13 @@ sub tags_subselect
     my($self)=@_;
     my $hasvals=$self->expecting_values();
     my $tree=$self->{tagtree};
-    use Data::Dumper;
-    print Dumper $tree;
+#    use Data::Dumper;
+#    print Dumper $tree;
     my ($sqlclause, @joins)=$tree->to_sql($hasvals) if($tree);
     my $sql="\tSELECT fxt1.files_id FROM tags t1";
     my @crosses=();
     my @inners=();
+    @joins=@{$self->{joins}};
     for(my $i=0; $i <= $#joins; $i++)
     {
 	my $cnt=$i+1;
diff --git a/lib/ID3FS/Path/Node.pm b/lib/ID3FS/Path/Node.pm
index a0a6b70..ee3f931 100644
--- a/lib/ID3FS/Path/Node.pm
+++ b/lib/ID3FS/Path/Node.pm
@@ -36,6 +36,8 @@ sub new
     $self->{type}=shift;
     $self->{name}=shift;
     $self->{parents_id}=shift;
+    $self->{table}=1;
+    $self->{join}=undef;
     if($self->{type} != $TYPE_BOOL)
     {
 	my $table='';
@@ -65,74 +67,39 @@ sub name       { return shift->set("name",       shift); }
 sub type       { return shift->set("type",       shift); }
 sub id         { return shift->set("id",         shift); }
 sub parents_id { return shift->set("parents_id", shift); }
+sub table      { return shift->set("table",      shift); }
+sub join       { return shift->set("join",       shift); }
 
 sub to_sql
 {
-    my($self, $hasvals, $not, @joins)=@_;
+    my($self, $hasvals, $not)=@_;
     $not=0 unless(defined($not));
-    my @outjoins=();
-    unless(@joins)
-    {
-	@outjoins = @joins = ("INNER");
-    }
+    $hasvals=0 unless(defined($hasvals));
     my $str='';
 
     if($self->type() != $TYPE_BOOL)
     {
-	print $self->{id}, " = ", $self->{name}, "\n";
-	$str .= "t" . scalar(@joins) . ".id='" . $self->{id} . "'";
+	$str .= "t" . $self->table() . ".id='" . $self->{id} . "'";
 	if($not && !$hasvals)
 	{
-	    $str = "(" . $str . " AND fxt" . scalar(@joins) . ".files_id IS NULL)";
+	    $str = "(" . $str . " AND fxt" . $self->table() . ".files_id IS NULL)";
 	}
-	return ($str, @outjoins);
+	return ($str);
     }
 
     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);
+    return ("") unless($left || $right);
 
+    my $leftstr = $left->to_sql($hasvals, $not) if($left);
     my $op=$self->name();
-    if(defined($op))
-    {
-	# if we are ANDing add an inner join
-	if($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
-#	    unless($right && $right->name() && $right->name() eq "NOT")
-#	    {
-		push(@joins, "INNER");
-		push(@outjoins, "INNER");
-#	    }
-	}
-	elsif($op eq "NOT")
-	{
-	    $not=1;
-	    # return an extra join, but don't pass it down to $right->to_sql
-	    # if we are looking for a tag *value*, use INNER join rather than LEFT
-	    push(@outjoins, ($hasvals ? "INNER" : "LEFT"));
-	}
-    }
-    my ($rightstr, @rightjoins) = $right->to_sql($hasvals, $not, @joins) if($right);
-    push(@outjoins, @rightjoins);
+    $not=1 if(defined($op) && ($op eq "NOT"));
+    my $rightstr = $right->to_sql($hasvals, $not) if($right);
     $str = $leftstr;
     $str .= " $op " if($op && !$not);
     $str .= $rightstr;
     $str=("(" . $str . ")") if($op && $left && $right);
-#    print "LEFT (", scalar(@$leftjoins), "): ";
-#    print $leftstr if $leftstr;
-#    print "\n";
-#    print "OP: $op\n" if $op;
-#    print "RIGHT (", scalar(@$rightjoins), "): ";
-#    print $rightstr if $rightstr;
-#    print "\n";
-    print "OUT(", scalar(@outjoins), "): $str\n";
-    return($str, @outjoins);
+    return($str);
 }
 
 sub used_tags
-- 
2.11.0