mid: add `mids' and `references' methods for extraction

[public-inbox.git] / lib / PublicInbox / MID.pm

diff --git a/lib/PublicInbox/MID.pm b/lib/PublicInbox/MID.pm
index 2c9822f478da32879866065c21a1f1f247297827..786c056f8593cac7d493689a1ce0774500629ff6 100644 (file)
--- a/lib/PublicInbox/MID.pm
+++ b/lib/PublicInbox/MID.pm
@@ -6,7 +6,8 @@ package PublicInbox::MID;
 use strict;
 use warnings;
 use base qw/Exporter/;
-our @EXPORT_OK = qw/mid_clean id_compress mid2path mid_mime mid_escape MID_ESC/;
+our @EXPORT_OK = qw/mid_clean id_compress mid2path mid_mime mid_escape MID_ESC
+       mids references/;
 use URI::Escape qw(uri_escape_utf8);
 use Digest::SHA qw/sha1_hex/;
 use constant MID_MAX => 40; # SHA-1 hex length
@@ -48,6 +49,27 @@ sub mid2path {
 
 sub mid_mime ($) { $_[0]->header_obj->header_raw('Message-ID') }
 
+sub uniq_mids {
+       my ($hdr, @fields) = @_;
+       my %seen;
+       my @raw;
+       foreach my $f (@fields) {
+               push @raw, $hdr->header_raw($f);
+       }
+       my @mids = (join(' ', @raw) =~ /<([^>]+)>/g);
+       my $mids = scalar(@mids) == 0 ? \@raw: \@mids;
+       my @ret;
+       foreach (@$mids) {
+               next if $seen{$_};
+               push @ret, $_;
+               $seen{$_} = 1;
+       }
+       \@ret;
+}
+
+sub mids { uniq_mids($_[0], 'Message-Id') }
+sub references { uniq_mids($_[0], 'References', 'In-Reply-To') }
+
 # RFC3986, section 3.3:
 sub MID_ESC () { '^A-Za-z0-9\-\._~!\$\&\';\(\)\*\+,;=:@' }
 sub mid_escape ($) { uri_escape_utf8($_[0], MID_ESC) }