# This license differs from the rest of public-inbox
#
# Our own jwz-style threading class based on Mail::Thread from CPAN.
-# Mail::Thread is unmaintained and available on some distros.
+# Mail::Thread is unmaintained and unavailable on some distros.
# We also do not want pruning or subject grouping, since we want
# to encourage strict threading and hopefully encourage people
-# to use proper In-Reply-To.
+# to use proper In-Reply-To/References.
#
# This includes fixes from several open bugs for Mail::Thread
#
use strict;
use warnings;
-sub new {
- return bless {
- messages => $_[1],
- id_table => {},
- rootset => []
- }, $_[0];
-}
-
sub thread {
- my $self = shift;
- _add_message($self, $_) foreach @{$self->{messages}};
- $self->{rootset} = [
- grep { !$_->{parent} } values %{$self->{id_table}} ];
- delete $self->{id_table};
+ my ($messages, $ordersub, $ibx) = @_;
+ my $id_table = {};
+ _add_message($id_table, $_) foreach @$messages;
+ my $rootset = [ grep {
+ !delete($_->{parent}) && $_->visible($ibx)
+ } values %$id_table ];
+ $id_table = undef;
+ $rootset = $ordersub->($rootset);
+ $_->order_children($ordersub, $ibx) for @$rootset;
+ $rootset;
}
sub _get_cont_for_id ($$) {
- my ($self, $mid) = @_;
- $self->{id_table}{$mid} ||= PublicInbox::SearchThread::Msg->new($mid);
+ my ($id_table, $mid) = @_;
+ $id_table->{$mid} ||= PublicInbox::SearchThread::Msg->new($mid);
}
sub _add_message ($$) {
- my ($self, $smsg) = @_;
+ my ($id_table, $smsg) = @_;
# A. if id_table...
- my $this = _get_cont_for_id($self, $smsg->{mid});
+ my $this = _get_cont_for_id($id_table, $smsg->{mid});
$this->{smsg} = $smsg;
# B. For each element in the message's References field:
+ defined(my $refs = $smsg->{references}) or return;
+
+ # This loop exists to help fill in gaps left from missing
+ # messages. It is not needed in a perfect world where
+ # everything is perfectly referenced, only the last ref
+ # matters.
my $prev;
- if (defined(my $refs = $smsg->{references})) {
- foreach my $ref ($refs =~ m/<([^>]+)>/g) {
- # Find a Container object for the given Message-ID
- my $cont = _get_cont_for_id($self, $ref);
-
- # Link the References field's Containers together in
- # the order implied by the References header
- #
- # * If they are already linked don't change the
- # existing links
- # * Do not add a link if adding that link would
- # introduce a loop...
- if ($prev &&
- !$cont->{parent} && # already linked
- !$cont->has_descendent($prev) # would loop
- ) {
- $prev->add_child($cont);
- }
- $prev = $cont;
+ foreach my $ref ($refs =~ m/<([^>]+)>/g) {
+ # Find a Container object for the given Message-ID
+ my $cont = _get_cont_for_id($id_table, $ref);
+
+ # Link the References field's Containers together in
+ # the order implied by the References header
+ #
+ # * If they are already linked don't change the
+ # existing links
+ # * Do not add a link if adding that link would
+ # introduce a loop...
+ if ($prev &&
+ !$cont->{parent} && # already linked
+ !$cont->has_descendent($prev) # would loop
+ ) {
+ $prev->add_child($cont);
}
+ $prev = $cont;
}
# C. Set the parent of this message to be the last element in
- # References...
- if ($prev && !$this->has_descendent($prev)) { # would loop
- $prev->add_child($this)
+ # References.
+ if (defined $prev && !$this->has_descendent($prev)) { # would loop
+ $prev->add_child($this);
}
}
-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;
-}
-
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(...)
+ }, $_[0];
+}
+
+sub topmost {
+ my ($self) = @_;
+ my @q = ($self);
+ while (my $cont = shift @q) {
+ return $cont if $cont->{smsg};
+ push @q, values %{$cont->{children}};
+ }
+ undef;
+}
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;
-
- $child->{next} = $self->{child};
- $self->{child} = $child;
- weaken($child->{parent} = $self);
-}
+ my $cid = $child->{id};
-sub remove_child {
- my ($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;
+ $self->{children}->{$cid} = $child;
+ $child->{parent} = $self;
}
sub has_descendent {
- my $self = shift;
- my $child = shift;
- die "Assertion failed: $child" unless eval {$child};
- my $there = 0;
- $self->recurse_down(sub { $there = 1 if $_[0] == $child });
-
- return $there;
-}
-
-sub children {
- my $self = shift;
- my @children;
- my $visitor = $self->{child};
- while ($visitor) {
- push @children, $visitor;
- $visitor = $visitor->{next};
+ my ($self, $child) = @_;
+ my %seen; # loop prevention
+ while ($child) {
+ return 1 if $self == $child || $seen{$child}++;
+ $child = $child->{parent};
}
- \@children;
+ 0;
}
-sub set_children {
- my ($self, $children) = @_;
- my $walk = $self->{child} = shift @$children;
- do {
- $walk = $walk->{next} = shift @$children;
- } while ($walk);
-}
-
-# non-recursive version of recurse_down to avoid stack depth warnings
-sub recurse_down {
- my ($self, $callback) = @_;
- my %seen;
- my @q = ($self);
- while (my $cont = shift @q) {
- $seen{$cont} = 1;
- $callback->($cont);
-
- 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;
- }
- }
- }
+# Do not show/keep ghosts iff they have no children. Sometimes
+# a ghost Message-ID is the result of a long header line
+# being folded/mangled by a MUA, and not a missing message.
+sub visible ($$) {
+ my ($self, $ibx) = @_;
+ ($self->{smsg} ||= eval { $ibx->smsg_by_mid($self->{id}) }) ||
+ (scalar values %{$self->{children}});
}
sub order_children {
- my ($walk, $ordersub) = @_;
+ my ($cur, $ordersub, $ibx) = @_;
- my %seen;
- my @visited;
- while ($walk) {
- push @visited, $walk;
-
- # spot/break loops
- $seen{$walk} = 1;
-
- my $child = $walk->{child};
- if ($child && $seen{$child}) {
- $walk->{child} = $child = undef;
- }
+ my %seen = ($cur => 1); # self-referential loop prevention
+ my @q = ($cur);
+ while (defined($cur = shift @q)) {
+ my $c = $cur->{children}; # The hashref here...
- 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{$_}++ && visible($_, $ibx) } values %$c ];
+ $c = $ordersub->($c) if scalar @$c > 1;
+ $cur->{children} = $c; # ...becomes an arrayref
+ push @q, @$c;
}
}