1 files changed, 104 insertions, 0 deletions
diff --git a/lib/PublicInbox/MHreader.pm b/lib/PublicInbox/MHreader.pm
new file mode 100644
index 00000000..16e505a2
--- /dev/null
+++ b/lib/PublicInbox/MHreader.pm
@@ -0,0 +1,104 @@
+# Copyright (C) all contributors <meta@public-inbox.org>
+# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
+
+# MH reader, based on Lib/mailbox.py in cpython source
+package PublicInbox::MHreader;
+use v5.12;
+use PublicInbox::InboxWritable qw(eml_from_path);
+use PublicInbox::OnDestroy;
+use PublicInbox::IO qw(try_cat);
+use PublicInbox::MdirSort;
+use Carp qw(carp);
+use autodie qw(chdir closedir opendir);
+
+my %FL2OFF = ( # mh_sequences key => our keyword
+        replied => 0,
+        flagged => 1,
+        unseen => 2, # negate
+);
+my @OFF2KW = qw(answered flagged); # [2] => unseen (negated)
+
+sub new {
+        my ($cls, $dir, $cwdfh) = @_;
+        if (substr($dir, -1) ne '/') { # TODO: do this earlier
+                carp "W: appending `/' to `$dir' (fix caller)\n";
+                $dir .= '/';
+        }
+        bless { dir => $dir, cwdfh => $cwdfh }, $cls;
+}
+
+sub read_mh_sequences ($) { # caller must chdir($self->{dir})
+        my ($self) = @_;
+        my ($fl, $off, @n);
+        my @seq = ('', '', '');
+        for (split /\n+/s, try_cat('.mh_sequences')) {
+                ($fl, @n) = split /[: \t]+/;
+                $off = $FL2OFF{$fl} // do { warn <<EOM;
+W: unknown `$fl' in $self->{dir}.mh_sequences (ignoring)
+EOM
+                        next;
+                };
+                @n = grep /\A[0-9]+\z/s, @n; # don't stat, yet
+                if (@n) {
+                        @n = sort { $b <=> $a } @n; # to avoid resize
+                        my $buf = '';
+                        vec($buf, $_, 1) = 1 for @n;
+                        $seq[$off] = $buf;
+                }
+        }
+        \@seq;
+}
+
+sub mh_each_file {
+        my ($self, $efcb, @arg) = @_;
+        opendir(my $dh, my $dir = $self->{dir});
+        my $restore = on_destroy \&chdir, $self->{cwdfh};
+        chdir($dh);
+        my $sort = $self->{sort};
+        if (defined $sort && "@$sort" ne 'none') {
+                my @sort = map {
+                        my @tmp = $_ eq '' ? ('sequence') : split(/[, ]/);
+                        # sorting by name alphabetically makes no sense for MH:
+                        for my $k (@tmp) {
+                                s/\A(\-|\+|)(?:name|)\z/$1sequence/;
+                        }
+                        @tmp;
+                } @$sort;
+                my @n = grep /\A[0-9]+\z/s, readdir $dh;
+                mdir_sort \@n, \@sort;
+                $efcb->($dir, $_, $self, @arg) for @n;
+        } else {
+                while (readdir $dh) { # perl v5.12+ to set $_ on readdir
+                        $efcb->($dir, $_, $self, @arg) if /\A[0-9]+\z/s;
+                }
+        }
+        closedir $dh; # may die
+}
+
+sub kw_for ($$) {
+        my ($self, $n) = @_;
+        my $seq = $self->{mh_seq} //= read_mh_sequences($self);
+        my @kw = map { vec($seq->[$_], $n, 1) ? $OFF2KW[$_] : () } (0, 1);
+        vec($seq->[2], $n, 1) or push @kw, 'seen';
+        \@kw;
+}
+
+sub _file2eml { # mh_each_file / mh_read_one cb
+        my ($dir, $n, $self, $ucb, @arg) = @_;
+        my $eml = eml_from_path($n);
+        $ucb->($dir, $n, kw_for($self, $n), $eml, @arg) if $eml;
+}
+
+sub mh_each_eml {
+        my ($self, $ucb, @arg) = @_;
+        mh_each_file($self, \&_file2eml, $ucb, @arg);
+}
+
+sub mh_read_one {
+        my ($self, $n, $ucb, @arg) = @_;
+        my $restore = on_destroy \&chdir, $self->{cwdfh};
+        chdir(my $dir = $self->{dir});
+        _file2eml($dir, $n, $self, $ucb, @arg);
+}
+
+1;