v2writable: add NNTP article number regeneration support

Allow best-effort regeneration of NNTP article numbers from
cloned git repositories in addition to indexing Xapian Article
numbers will not remain consistent when we add purge support,
though.

1 files changed, 54 insertions, 7 deletions

diff --git a/lib/PublicInbox/V2Writable.pm b/lib/PublicInbox/V2Writable.pm
index 550a74d4..605f6887 100644
--- a/lib/PublicInbox/V2Writable.pm
+++ b/lib/PublicInbox/V2Writable.pm
@@ -494,7 +494,7 @@ sub mark_deleted {
 }
 
 sub reindex_oid {
-        my ($self, $mm_tmp, $D, $git, $oid) = @_;
+        my ($self, $mm_tmp, $D, $git, $oid, $regen) = @_;
         my $len;
         my $msgref = $git->cat_file($oid, \$len);
         my $mime = PublicInbox::MIME->new($$msgref);
@@ -514,8 +514,27 @@ sub reindex_oid {
                         $num = $n;
                 }
         }
+        if (!defined($mid0) && $regen && !$del) {
+                $num = $$regen--;
+                die "BUG: ran out of article numbers\n" if $num <= 0;
+                my $mm = $self->{skel}->{mm};
+                foreach my $mid (@$mids) {
+                        if ($mm->mid_set($num, $mid) == 1) {
+                                $mid0 = $mid;
+                                last;
+                        }
+                }
+                if (!defined($mid0)) {
+                        my $id = '<' . join('> <', @$mids) . '>';
+                        warn "Message-Id $id unusable for $num\n";
+                }
+        }
+
         if (!defined($mid0) || $del) {
-                return if (!defined($mid0) && $del); # expected for deletes
+                if (!defined($mid0) && $del) { # expected for deletes
+                        $$regen--;
+                        return
+                }
 
                 my $id = '<' . join('> <', @$mids) . '>';
                 defined($mid0) or
@@ -546,19 +565,45 @@ sub reindex_oid {
 }
 
 sub reindex {
-        my ($self) = @_;
+        my ($self, $regen) = @_;
         my $ibx = $self->{-inbox};
         my $pfx = "$ibx->{mainrepo}/git";
         my $max_git;
         my $latest = git_dir_latest($self, \$max_git);
         return unless defined $latest;
-        my @cmd = qw(log --raw -r --pretty=tformat:%h
-                        --no-notes --no-color --no-abbrev);
         my $head = $ibx->{ref_head} || 'refs/heads/master';
         $self->idx_init; # acquire lock
         my $x40 = qr/[a-f0-9]{40}/;
         my $mm_tmp = $self->{skel}->{mm}->tmp_clone;
+        if (!$regen) {
+                my (undef, $max) = $mm_tmp->minmax;
+                unless (defined $max) {
+                        $regen = 1;
+                        warn
+"empty msgmap.sqlite3, regenerating article numbers\n";
+                }
+        }
+        my $tip; # latest commit out of all git repos
+        if ($regen) {
+                my $regen_max = 0;
+                for (my $cur = $max_git; $cur >= 0; $cur--) {
+                        die "already reindexing!\n" if $self->{reindex_pipe};
+                        my $git = PublicInbox::Git->new("$pfx/$cur.git");
+                        chomp($tip = $git->qx('rev-parse', $head)) unless $tip;
+                        my $h = $cur == $max_git ? $tip : $head;
+                        my @count = ('rev-list', '--count', $h, '--', 'm');
+                        $regen_max += $git->qx(@count);
+                }
+                die "No messages found in $pfx/*.git, bug?\n" unless $regen_max;
+                $regen = \$regen_max;
+        }
         my $D = {};
+        my @cmd = qw(log --raw -r --pretty=tformat:%h
+                        --no-notes --no-color --no-abbrev);
+
+        # if we are regenerating, we must not use a newer tip commit than what
+        # the regeneration counter used:
+        $tip ||= $head;
 
         # work backwards through history
         for (my $cur = $max_git; $cur >= 0; $cur--) {
@@ -566,12 +611,14 @@ sub reindex {
                 my $cmt;
                 my $git_dir = "$pfx/$cur.git";
                 my $git = PublicInbox::Git->new($git_dir);
-                my $fh = $self->{reindex_pipe} = $git->popen(@cmd, $head);
+                my $h = $cur == $max_git ? $tip : $head;
+                my $fh = $self->{reindex_pipe} = $git->popen(@cmd, $h);
                 while (<$fh>) {
                         if (/\A$x40$/o) {
                                 chomp($cmt = $_);
                         } elsif (/\A:\d{6} 100644 $x40 ($x40) [AM]\tm$/o) {
-                                $self->reindex_oid($mm_tmp, $D, $git, $1);
+                                $self->reindex_oid($mm_tmp, $D, $git, $1,
+                                                $regen);
                         } elsif (m!\A:\d{6} 100644 $x40 ($x40) [AM]\t_/D$!o) {
                                 $self->mark_deleted($D, $git, $1);
                         }