# 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
#
package PublicInbox::SearchThread;
use strict;
use warnings;
-use Email::Abstract;
-
-sub new {
- return bless {
- messages => $_[1],
- id_table => {},
- rootset => []
- }, $_[0];
-}
-
-sub _get_hdr {
- my ($class, $msg, $hdr) = @_;
- Email::Abstract->get_header($msg, $hdr) || '';
-}
-
-sub _uniq {
- my %seen;
- return grep { !$seen{$_}++ } @_;
-}
-
-sub _references {
- my $class = shift;
- my $msg = shift;
- my @references = ($class->_get_hdr($msg, "References") =~ /<([^>]+)>/g);
- my $foo = $class->_get_hdr($msg, "In-Reply-To");
- chomp $foo;
- $foo =~ s/.*?<([^>]+)>.*/$1/;
- push @references, $foo
- if $foo =~ /^\S+\@\S+$/ && (!@references || $references[-1] ne $foo);
- return _uniq(@references);
-}
-
-sub _msgid {
- my ($class, $msg) = @_;
- my $id = $class->_get_hdr($msg, "Message-ID");
- die "attempt to thread message with no id" unless $id;
- chomp $id;
- $id =~ s/^<([^>]+)>.*/$1/; # We expect this not to have <>s
- return $id;
-}
-
-sub rootset { @{$_[0]{rootset}} }
sub thread {
- my $self = shift;
- $self->_setup();
- $self->{rootset} = [ grep { !$_->parent } values %{$self->{id_table}} ];
- $self->_finish();
-}
-
-sub _finish {
- my $self = shift;
- delete $self->{id_table};
- delete $self->{seen};
-}
-
-sub _get_cont_for_id {
- my $self = shift;
- my $id = shift;
- $self->{id_table}{$id} ||= $self->_container_class->new($id);
+ 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;
+ $rootset;
}
-sub _container_class { 'PublicInbox::SearchThread::Container' }
-
-sub _setup {
- my ($self) = @_;
-
- _add_message($self, $_) foreach @{$self->{messages}};
+sub _get_cont_for_id ($$) {
+ my ($id_table, $mid) = @_;
+ $id_table->{$mid} ||= PublicInbox::SearchThread::Msg->new($mid);
}
sub _add_message ($$) {
- my ($self, $message) = @_;
+ my ($id_table, $smsg) = @_;
# A. if id_table...
- my $this_container = $self->_get_cont_for_id($self->_msgid($message));
- $this_container->message($message);
+ my $this = _get_cont_for_id($id_table, $smsg->{mid});
+ $this->{smsg} = $smsg;
# B. For each element in the message's References field:
- my @refs = $self->_references($message);
+ 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;
- for my $ref (@refs) {
+ foreach my $ref ($refs =~ m/<([^>]+)>/g) {
# Find a Container object for the given Message-ID
- my $container = $self->_get_cont_for_id($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...
-
+ 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 &&
- !$container->parent && # already linked
- !$container->has_descendent($prev) # would loop
+ !$cont->{parent} && # already linked
+ !$cont->has_descendent($prev) # would loop
) {
- $prev->add_child($container);
+ $prev->add_child($cont);
}
- $prev = $container;
+ $prev = $cont;
}
# C. Set the parent of this message to be the last element in
- # References...
- if ($prev &&
- !$this_container->has_descendent($prev) # would loop
- ) {
- $prev->add_child($this_container)
+ # References.
+ if (defined $prev && !$this->has_descendent($prev)) { # would loop
+ $prev->add_child($this);
}
}
-sub order {
- my $self = shift;
- my $ordersub = shift;
-
- # make a fake root
- my $root = $self->_container_class->new( '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::Container;
+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 message { $_[0]->{message} = $_[1] if @_ == 2; $_[0]->{message} }
-sub parent { @_ == 2 ? weaken($_[0]->{parent} = $_[1]) : $_[0]->{parent} }
-sub child { $_[0]->{child} = $_[1] if @_ == 2; $_[0]->{child} }
-sub next { $_[0]->{next} = $_[1] if @_ == 2; $_[0]->{next} }
-sub messageid { $_[0]->{id} }
+sub topmost {
+ my ($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
- $child->parent($self);
- return;
- }
-
- $child->parent->remove_child($child) if $child->parent;
+ my $cid = $child->{id};
- $child->next($self->child);
- $self->child($child);
- $child->parent($self);
-}
-
-sub remove_child {
- my ($self, $child) = @_;
- return unless $self->child;
- if ($self->child == $child) { # First one's easy.
- $self->child($child->next);
- $child->next(undef);
- $child->parent(undef);
- return;
+ # reparenting:
+ if (defined(my $parent = $child->{parent})) {
+ delete $parent->{children}->{$cid};
}
- my $x = $self->child;
- my $prev = $x;
- while ($x = $x->next) {
- if ($x == $child) {
- $prev->next($x->next); # Unlink x
- $x->next(undef);
- $x->parent(undef); # Deparent it
- return;
- }
- $prev = $x;
- }
- # oddly, we can get here
- $child->next(undef);
- $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};
}
- return @children;
+ 0;
}
-sub set_children {
- my $self = shift;
- my $walk = $self->child( shift );
- while (@_) { $walk = $walk->next( shift ) }
- $walk->next(undef) if $walk;
+# 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 $self = shift;
- my $ordersub = shift;
-
- return unless $ordersub;
-
- my $sub = sub {
- my $cont = shift;
- my @children = $cont->children;
- return if @children < 2;
- $cont->set_children( $ordersub->( @children ) );
- };
- $self->iterate_down( undef, $sub );
- undef $sub;
-}
+ my ($cur, $ordersub, $ibx) = @_;
-# non-recursive version of recurse_down to avoid stack depth warnings
-sub recurse_down {
- my ($self, $callback) = @_;
- my %seen;
- my @q = ($self);
- while (my $cont = shift @q) {
- $seen{$cont}++;
- $callback->($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;
- }
- }
- }
-}
-
-sub iterate_down {
- my $self = shift;
- my ($before, $after) = @_;
-
- my %seen;
- my $walk = $self;
- my $depth = 0;
- my @visited;
- while ($walk) {
- push @visited, [ $walk, $depth ];
- $before->($walk, $depth) if $before;
+ my %seen = ($cur => 1); # self-referential loop prevention
+ my @q = ($cur);
+ while (defined($cur = shift @q)) {
+ my $c = $cur->{children}; # The hashref here...
- # spot/break loops
- $seen{$walk}++;
-
- my $child = $walk->child;
- if ($child && $seen{$child}) {
- $walk->child(undef);
- $child = undef;
- }
-
- my $next = $walk->next;
- if ($next && $seen{$next}) {
- $walk->next(undef);
- $next = undef;
- }
-
- # go down, or across
- if ($child) {
- $next = $child;
- ++$depth;
- }
-
- # no next? look up
- if (!$next) {
- my $up = $walk;
- while ($up && !$next) {
- $up = $up->parent;
- --$depth;
- $next = $up->next if $up;
- }
- }
- $walk = $next;
+ $c = [ grep { !$seen{$_}++ && visible($_, $ibx) } values %$c ];
+ $c = $ordersub->($c) if scalar @$c > 1;
+ $cur->{children} = $c; # ...becomes an arrayref
+ push @q, @$c;
}
- return unless $after;
- while (@visited) { $after->(@{ pop @visited }) }
}
1;