]> Sergey Matveev's repositories - public-inbox.git/blobdiff - lib/PublicInbox/SearchThread.pm
thread: use hash + array instead of hand-rolled linked list
[public-inbox.git] / lib / PublicInbox / SearchThread.pm
index 153eef2b32176412efd85cd3f007d70a1e3d3465..05de9ec5b84d270fefc34b8b709a4e1d2c9ca292 100644 (file)
@@ -32,9 +32,8 @@ sub new {
 sub thread {
        my $self = shift;
        _add_message($self, $_) foreach @{$self->{messages}};
-       $self->{rootset} = [
-                       grep { !$_->{parent} } values %{$self->{id_table}} ];
-       delete $self->{id_table};
+       my $id_table = delete $self->{id_table};
+       $self->{rootset} = [ grep { !$_->{parent} } values %$id_table ];
 }
 
 sub _get_cont_for_id ($$) {
@@ -82,156 +81,67 @@ sub _add_message ($$) {
 
 sub order {
        my ($self, $ordersub) = @_;
-
-       # make a fake root
-       my $root = _get_cont_for_id($self, 'fakeroot');
-       $root->add_child( $_ ) for @{ $self->{rootset} };
-
-       # sort it
-       $root->order_children( $ordersub );
-
-       # and untangle it
-       my $kids = $root->children;
-       $self->{rootset} = $kids;
-       $root->remove_child($_) for @$kids;
+       my $rootset = $ordersub->($self->{rootset});
+       $self->{rootset} = $rootset;
+       $_->order_children($ordersub) for @$rootset;
 }
 
 package PublicInbox::SearchThread::Msg;
+use strict;
+use warnings;
 use Carp qw(croak);
 use Scalar::Util qw(weaken);
 
-sub new { my $self = shift; bless { id => shift }, $self; }
+sub new {
+       bless {
+               id => $_[1],
+               children => {}, # becomes an array when sorted by ->order(...)
+       }, $_[0];
+}
 
 sub add_child {
        my ($self, $child) = @_;
        croak "Cowardly refusing to become my own parent: $self"
          if $self == $child;
 
-       if (grep { $_ == $child } @{$self->children}) {
-               # All is potentially correct with the world
-               weaken($child->{parent} = $self);
-               return;
-       }
-
-       my $parent = $child->{parent};
-       remove_child($parent, $child) if $parent;
+       my $cid = $child->{id};
+       $self->{children}->{$cid} = $child;
 
-       $child->{next} = $self->{child};
-       $self->{child} = $child;
-       weaken($child->{parent} = $self);
-}
-
-sub remove_child {
-       my ($self, $child) = @_;
-
-       my $x = $self->{child} or return;
-       if ($x == $child) {  # First one's easy.
-               $self->{child} = $child->{next};
-               $child->{parent} = $child->{next} = undef;
-               return;
+       # reparenting:
+       if (defined(my $parent = $child->{parent})) {
+               delete $parent->{children}->{$cid};
        }
 
-       my $prev = $x;
-       while ($x = $x->{next}) {
-               if ($x == $child) {
-                       $prev->{next} = $x->{next}; # Unlink x
-                       $x->{next} = $x->{parent} = undef; # Deparent it
-                       return;
-               }
-               $prev = $x;
-       }
-       # oddly, we can get here
-       $child->{next} = $child->{parent} = undef;
+       weaken($child->{parent} = $self);
 }
 
 sub has_descendent {
-       my ($self, $child) = @_;
+       my ($cur, $child) = @_;
        my %seen;
-       my @q = ($self);
-       while (my $cont = shift @q) {
-               $seen{$cont} = 1;
+       my @q = ($cur->{parent} || $cur);
 
-               return 1 if $cont == $child;
+       while (defined($cur = shift @q)) {
+               return 1 if $cur == $child;
 
-               if (my $next = $cont->{next}) {
-                       if ($seen{$next}) {
-                               $cont->{next} = undef;
-                       } else {
-                               push @q, $next;
-                       }
-               }
-               if (my $child = $cont->{child}) {
-                       if ($seen{$child}) {
-                               $cont->{child} = undef;
-                       } else {
-                               push @q, $child;
-                       }
+               if (!$seen{$cur}++) {
+                       push @q, values %{$cur->{children}};
                }
        }
        0;
 }
 
-sub children {
-       my $self = shift;
-       my @children;
-       my $visitor = $self->{child};
-       while ($visitor) {
-               push @children, $visitor;
-               $visitor = $visitor->{next};
-       }
-       \@children;
-}
-
-sub set_children {
-       my ($self, $children) = @_;
-       my $walk = $self->{child} = shift @$children;
-       do {
-               $walk = $walk->{next} = shift @$children;
-       } while ($walk);
-}
-
 sub order_children {
-       my ($walk, $ordersub) = @_;
+       my ($cur, $ordersub) = @_;
 
-       my %seen;
-       my @visited;
-       while ($walk) {
-               push @visited, $walk;
+       my %seen = ($cur => 1);
+       my @q = ($cur);
+       while (defined($cur = shift @q)) {
+               my $c = $cur->{children}; # The hashref here...
 
-               # spot/break loops
-               $seen{$walk} = 1;
-
-               my $child = $walk->{child};
-               if ($child && $seen{$child}) {
-                       $walk->{child} = $child = undef;
-               }
-
-               my $next = $walk->{next};
-               if ($next && $seen{$next}) {
-                       $walk->{next} = $next = undef;
-               }
-
-               # go down, or across
-               $next = $child if $child;
-
-               # no next?  look up
-               if (!$next) {
-                       my $up = $walk;
-                       while ($up && !$next) {
-                               $up = $up->{parent};
-                               $next = $up->{next} if $up;
-                       }
-               }
-               $walk = $next;
-       }
-       foreach my $cont (@visited) {
-               my $children = $cont->children;
-               next if @$children < 2;
-               $children = $ordersub->($children);
-               $cont = $cont->{child} = shift @$children;
-               do {
-                       $cont = $cont->{next} = shift @$children;
-               } while ($cont);
+               $c = [ grep { !$seen{$_}++ } values %$c ]; # spot/break loops
+               $c = $ordersub->($c) if scalar @$c > 1;
+               $cur->{children} = $c; # ...becomes an arrayref
+               push @q, @$c;
        }
 }