user/dev discussion of public-inbox itself
 help / color / Atom feed
222df5c2ffa6d0cf3dae884ea734ee9973dc1619 blob 25285 bytes (raw)

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
 
# Copyright (C) 2018 all contributors <meta@public-inbox.org>
# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>

# This interface wraps and mimics PublicInbox::Import
# Used to write to V2 inboxes (see L<public-inbox-v2-format(5)>).
package PublicInbox::V2Writable;
use strict;
use warnings;
use base qw(PublicInbox::Lock);
use PublicInbox::SearchIdxPart;
use PublicInbox::MIME;
use PublicInbox::Git;
use PublicInbox::Import;
use PublicInbox::MID qw(mids);
use PublicInbox::ContentId qw(content_id content_digest);
use PublicInbox::Inbox;
use PublicInbox::OverIdx;
use PublicInbox::Msgmap;
use PublicInbox::Spawn qw(spawn);
use PublicInbox::SearchIdx;
use IO::Handle;

# an estimate of the post-packed size to the raw uncompressed size
my $PACKING_FACTOR = 0.4;

# assume 2 cores if GNU nproc(1) is not available
sub nproc_parts () {
	my $n = int($ENV{NPROC} || `nproc 2>/dev/null` || 2);
	# subtract for the main process and git-fast-import
	$n -= 1;
	$n < 1 ? 1 : $n;
}

sub count_partitions ($) {
	my ($self) = @_;
	my $nparts = 0;
	my $xpfx = $self->{xpfx};

	# always load existing partitions in case core count changes:
	# Also, partition count may change while -watch is running
	# due to -compact
	if (-d $xpfx) {
		foreach my $part (<$xpfx/*>) {
			-d $part && $part =~ m!/\d+\z! or next;
			eval {
				Search::Xapian::Database->new($part)->close;
				$nparts++;
			};
		}
	}
	$nparts;
}

sub new {
	my ($class, $v2ibx, $creat) = @_;
	my $dir = $v2ibx->{mainrepo} or die "no mainrepo in inbox\n";
	unless (-d $dir) {
		if ($creat) {
			require File::Path;
			File::Path::mkpath($dir);
		} else {
			die "$dir does not exist\n";
		}
	}

	$v2ibx = PublicInbox::InboxWritable->new($v2ibx);
	$v2ibx->umask_prepare;

	my $xpfx = "$dir/xap" . PublicInbox::Search::SCHEMA_VERSION;
	my $self = {
		-inbox => $v2ibx,
		im => undef, #  PublicInbox::Import
		parallel => 1,
		transact_bytes => 0,
		xpfx => $xpfx,
		over => PublicInbox::OverIdx->new("$xpfx/over.sqlite3", 1),
		lock_path => "$dir/inbox.lock",
		# limit each git repo (epoch) to 1GB or so
		rotate_bytes => int((1024 * 1024 * 1024) / $PACKING_FACTOR),
		last_commit => [], # git repo -> commit
	};
	$self->{partitions} = count_partitions($self) || nproc_parts();
	bless $self, $class;
}

sub init_inbox {
	my ($self, $parallel, $skip) = @_;
	$self->{parallel} = $parallel;
	$self->idx_init;
	my $epoch_max = -1;
	git_dir_latest($self, \$epoch_max);
	if (defined $skip && $epoch_max == -1) {
		$epoch_max = $skip;
	}
	$self->git_init($epoch_max >= 0 ? $epoch_max : 0);
	$self->done;
}

# returns undef on duplicate or spam
# mimics Import::add and wraps it for v2
sub add {
	my ($self, $mime, $check_cb) = @_;
	$self->{-inbox}->with_umask(sub {
		_add($self, $mime, $check_cb)
	});
}

sub _add {
	my ($self, $mime, $check_cb) = @_;

	# spam check:
	if ($check_cb) {
		$mime = $check_cb->($mime) or return;
	}

	# All pipes (> $^F) known to Perl 5.6+ have FD_CLOEXEC set,
	# as does SQLite 3.4.1+ (released in 2007-07-20), and
	# Xapian 1.3.2+ (released 2015-03-15).
	# For the most part, we can spawn git-fast-import without
	# leaking FDs to it...
	$self->idx_init;

	my $mid0;
	my $num = num_for($self, $mime, \$mid0);
	defined $num or return; # duplicate
	defined $mid0 or die "BUG: $mid0 undefined\n";
	my $im = $self->importer;
	my $cmt = $im->add($mime);
	$cmt = $im->get_mark($cmt);
	$self->{last_commit}->[$self->{epoch_max}] = $cmt;

	my ($oid, $len, $msgref) = @{$im->{last_object}};
	$self->{over}->add_overview($mime, $len, $num, $oid, $mid0);
	my $nparts = $self->{partitions};
	my $part = $num % $nparts;
	my $idx = $self->idx_part($part);
	$idx->index_raw($len, $msgref, $num, $oid, $mid0, $mime);
	my $n = $self->{transact_bytes} += $len;
	if ($n > (PublicInbox::SearchIdx::BATCH_BYTES * $nparts)) {
		$self->checkpoint;
	}

	$cmt;
}

sub num_for {
	my ($self, $mime, $mid0) = @_;
	my $mids = mids($mime->header_obj);
	if (@$mids) {
		my $mid = $mids->[0];
		my $num = $self->{mm}->mid_insert($mid);
		if (defined $num) { # common case
			$$mid0 = $mid;
			return $num;
		};

		# crap, Message-ID is already known, hope somebody just resent:
		foreach my $m (@$mids) {
			# read-only lookup now safe to do after above barrier
			my $existing = $self->lookup_content($mime, $m);
			# easy, don't store duplicates
			# note: do not add more diagnostic info here since
			# it gets noisy on public-inbox-watch restarts
			return if $existing;
		}

		# AltId may pre-populate article numbers (e.g. X-Mail-Count
		# or NNTP article number), use that article number if it's
		# not in Over.
		my $altid = $self->{-inbox}->{altid};
		if ($altid && grep(/:file=msgmap\.sqlite3\z/, @$altid)) {
			my $num = $self->{mm}->num_for($mid);

			if (defined $num && !$self->{over}->get_art($num)) {
				$$mid0 = $mid;
				return $num;
			}
		}

		# very unlikely:
		warn "<$mid> reused for mismatched content\n";

		# try the rest of the mids
		for(my $i = $#$mids; $i >= 1; $i--) {
			my $m = $mids->[$i];
			$num = $self->{mm}->mid_insert($m);
			if (defined $num) {
				warn "alternative <$m> for <$mid> found\n";
				$$mid0 = $m;
				return $num;
			}
		}
	}
	# none of the existing Message-IDs are good, generate a new one:
	num_for_harder($self, $mime, $mid0);
}

sub num_for_harder {
	my ($self, $mime, $mid0) = @_;

	my $hdr = $mime->header_obj;
	my $dig = content_digest($mime);
	$$mid0 = PublicInbox::Import::digest2mid($dig, $hdr);
	my $num = $self->{mm}->mid_insert($$mid0);
	unless (defined $num) {
		# it's hard to spoof the last Received: header
		my @recvd = $hdr->header_raw('Received');
		$dig->add("Received: $_") foreach (@recvd);
		$$mid0 = PublicInbox::Import::digest2mid($dig, $hdr);
		$num = $self->{mm}->mid_insert($$mid0);

		# fall back to a random Message-ID and give up determinism:
		until (defined($num)) {
			$dig->add(rand);
			$$mid0 = PublicInbox::Import::digest2mid($dig, $hdr);
			warn "using random Message-ID <$$mid0> as fallback\n";
			$num = $self->{mm}->mid_insert($$mid0);
		}
	}
	PublicInbox::Import::append_mid($hdr, $$mid0);
	$num;
}

sub idx_part {
	my ($self, $part) = @_;
	$self->{idx_parts}->[$part];
}

# idempotent
sub idx_init {
	my ($self) = @_;
	return if $self->{idx_parts};
	my $ibx = $self->{-inbox};

	# do not leak read-only FDs to child processes, we only have these
	# FDs for duplicate detection so they should not be
	# frequently activated.
	delete $ibx->{$_} foreach (qw(git mm search));

	my $indexlevel = $ibx->{indexlevel};
	if ($indexlevel && $indexlevel eq 'basic') {
		$self->{parallel} = 0;
	}

	if ($self->{parallel}) {
		pipe(my ($r, $w)) or die "pipe failed: $!";
		# pipe for barrier notifications doesn't need to be big,
		# 1031: F_SETPIPE_SZ
		fcntl($w, 1031, 4096) if $^O eq 'linux';
		$self->{bnote} = [ $r, $w ];
		$w->autoflush(1);
	}

	my $over = $self->{over};
	$ibx->umask_prepare;
	$ibx->with_umask(sub {
		$self->lock_acquire;
		$over->create;

		# -compact can change partition count while -watch is idle
		my $nparts = count_partitions($self);
		if ($nparts && $nparts != $self->{partitions}) {
			$self->{partitions} = $nparts;
		}

		# need to create all parts before initializing msgmap FD
		my $max = $self->{partitions} - 1;

		# idx_parts must be visible to all forked processes
		my $idx = $self->{idx_parts} = [];
		for my $i (0..$max) {
			push @$idx, PublicInbox::SearchIdxPart->new($self, $i);
		}

		# Now that all subprocesses are up, we can open the FDs
		# for SQLite:
		my $mm = $self->{mm} = PublicInbox::Msgmap->new_file(
			"$self->{-inbox}->{mainrepo}/msgmap.sqlite3", 1);
		$mm->{dbh}->begin_work;
	});
}

sub purge_oids {
	my ($self, $purge) = @_; # $purge = { $object_id => 1, ... }
	$self->done;
	my $pfx = "$self->{-inbox}->{mainrepo}/git";
	my $purges = [];
	foreach my $i (0..$self->{epoch_max}) {
		my $git = PublicInbox::Git->new("$pfx/$i.git");
		my $im = $self->import_init($git, 0, 1);
		$purges->[$i] = $im->purge_oids($purge);
	}
	$purges;
}

sub content_ids ($) {
	my ($mime) = @_;
	my @cids = ( content_id($mime) );

	# Email::MIME->as_string doesn't always round-trip, so we may
	# use a second content_id
	my $rt = content_id(PublicInbox::MIME->new(\($mime->as_string)));
	push @cids, $rt if $cids[0] ne $rt;
	\@cids;
}

sub content_matches ($$) {
	my ($cids, $existing) = @_;
	my $cid = content_id($existing);
	foreach (@$cids) {
		return 1 if $_ eq $cid
	}
	0
}

sub remove_internal {
	my ($self, $mime, $cmt_msg, $purge) = @_;
	$self->idx_init;
	my $im = $self->importer unless $purge;
	my $over = $self->{over};
	my $cids = content_ids($mime);
	my $parts = $self->{idx_parts};
	my $mm = $self->{mm};
	my $removed;
	my $mids = mids($mime->header_obj);

	# We avoid introducing new blobs into git since the raw content
	# can be slightly different, so we do not need the user-supplied
	# message now that we have the mids and content_id
	$mime = undef;
	my $mark;

	foreach my $mid (@$mids) {
		my %gone;
		my ($id, $prev);
		while (my $smsg = $over->next_by_mid($mid, \$id, \$prev)) {
			my $msg = get_blob($self, $smsg);
			if (!defined($msg)) {
				warn "broken smsg for $mid\n";
				next; # continue
			}
			my $orig = $$msg;
			my $cur = PublicInbox::MIME->new($msg);
			if (content_matches($cids, $cur)) {
				$smsg->{mime} = $cur;
				$gone{$smsg->{num}} = [ $smsg, \$orig ];
			}
		}
		my $n = scalar keys %gone;
		next unless $n;
		if ($n > 1) {
			warn "BUG: multiple articles linked to <$mid>\n",
				join(',', sort keys %gone), "\n";
		}
		foreach my $num (keys %gone) {
			my ($smsg, $orig) = @{$gone{$num}};
			$mm->num_delete($num);
			# $removed should only be set once assuming
			# no bugs in our deduplication code:
			$removed = $smsg;
			my $oid = $smsg->{blob};
			if ($purge) {
				$purge->{$oid} = 1;
			} else {
				($mark, undef) = $im->remove($orig, $cmt_msg);
			}
			$orig = undef;
			$self->unindex_oid_remote($oid, $mid);
		}
	}

	if (defined $mark) {
		my $cmt = $im->get_mark($mark);
		$self->{last_commit}->[$self->{epoch_max}] = $cmt;
	}
	if ($purge && scalar keys %$purge) {
		return purge_oids($self, $purge);
	}
	$removed;
}

sub remove {
	my ($self, $mime, $cmt_msg) = @_;
	$self->{-inbox}->with_umask(sub {
		remove_internal($self, $mime, $cmt_msg);
	});
}

sub purge {
	my ($self, $mime) = @_;
	my $purges = $self->{-inbox}->with_umask(sub {
		remove_internal($self, $mime, undef, {});
	});
	$self->idx_init if @$purges; # ->done is called on purges
	for my $i (0..$#$purges) {
		defined(my $cmt = $purges->[$i]) or next;
		$self->{last_commit}->[$i] = $cmt;
	}
	$purges;
}

sub last_commit_part ($$;$) {
	my ($self, $i, $cmt) = @_;
	my $v = PublicInbox::Search::SCHEMA_VERSION();
	$self->{mm}->last_commit_xap($v, $i, $cmt);
}

sub set_last_commits ($) {
	my ($self) = @_;
	defined(my $epoch_max = $self->{epoch_max}) or return;
	my $last_commit = $self->{last_commit};
	foreach my $i (0..$epoch_max) {
		defined(my $cmt = $last_commit->[$i]) or next;
		$last_commit->[$i] = undef;
		last_commit_part($self, $i, $cmt);
	}
}

sub barrier_init {
	my ($self, $n) = @_;
	$self->{bnote} or return;
	--$n;
	my $barrier = { map { $_ => 1 } (0..$n) };
}

sub barrier_wait {
	my ($self, $barrier) = @_;
	my $bnote = $self->{bnote} or return;
	my $r = $bnote->[0];
	while (scalar keys %$barrier) {
		defined(my $l = $r->getline) or die "EOF on barrier_wait: $!";
		$l =~ /\Abarrier (\d+)/ or die "bad line on barrier_wait: $l";
		delete $barrier->{$1} or die "bad part[$1] on barrier wait";
	}
}

sub checkpoint ($;$) {
	my ($self, $wait) = @_;

	if (my $im = $self->{im}) {
		if ($wait) {
			$im->barrier;
		} else {
			$im->checkpoint;
		}
	}
	my $parts = $self->{idx_parts};
	if ($parts) {
		my $dbh = $self->{mm}->{dbh};

		# SQLite msgmap data is second in importance
		$dbh->commit;

		# SQLite overview is third
		$self->{over}->commit_lazy;

		# Now deal with Xapian
		if ($wait) {
			my $barrier = $self->barrier_init(scalar @$parts);

			# each partition needs to issue a barrier command
			$_->remote_barrier for @$parts;

			# wait for each Xapian partition
			$self->barrier_wait($barrier);
		} else {
			$_->remote_commit for @$parts;
		}

		# last_commit is special, don't commit these until
		# remote partitions are done:
		$dbh->begin_work;
		set_last_commits($self);
		$dbh->commit;

		$dbh->begin_work;
	}
	$self->{transact_bytes} = 0;
}

# issue a write barrier to ensure all data is visible to other processes
# and read-only ops.  Order of data importance is: git > SQLite > Xapian
sub barrier { checkpoint($_[0], 1) };

sub done {
	my ($self) = @_;
	my $im = delete $self->{im};
	$im->done if $im; # PublicInbox::Import::done
	checkpoint($self);
	my $mm = delete $self->{mm};
	$mm->{dbh}->commit if $mm;
	my $parts = delete $self->{idx_parts};
	if ($parts) {
		$_->remote_close for @$parts;
	}
	$self->{over}->disconnect;
	delete $self->{bnote};
	$self->{transact_bytes} = 0;
	$self->lock_release if $parts;
}

sub git_init {
	my ($self, $epoch) = @_;
	my $pfx = "$self->{-inbox}->{mainrepo}/git";
	my $git_dir = "$pfx/$epoch.git";
	my @cmd = (qw(git init --bare -q), $git_dir);
	PublicInbox::Import::run_die(\@cmd);

	my $all = "$self->{-inbox}->{mainrepo}/all.git";
	unless (-d $all) {
		@cmd = (qw(git init --bare -q), $all);
		PublicInbox::Import::run_die(\@cmd);
		@cmd = (qw/git config/, "--file=$all/config",
				'repack.writeBitmaps', 'true');
		PublicInbox::Import::run_die(\@cmd);
	}

	@cmd = (qw/git config/, "--file=$git_dir/config",
			'include.path', '../../all.git/config');
	PublicInbox::Import::run_die(\@cmd);

	my $alt = "$all/objects/info/alternates";
	my %alts;
	my @add;
	if (-e $alt) {
		open(my $fh, '<', $alt) or die "open < $alt: $!\n";
		%alts = map { chomp; $_ => 1 } (<$fh>);
	}
	foreach my $i (0..$epoch) {
		my $dir = "../../git/$i.git/objects";
		push @add, $dir if !$alts{$dir} && -d "$pfx/$i.git";
	}
	return $git_dir unless @add;
	open my $fh, '>>', $alt or die "open >> $alt: $!\n";
	foreach my $dir (@add) {
		print $fh "$dir\n" or die "print >> $alt: $!\n";
	}
	close $fh or die "close $alt: $!\n";
	$git_dir
}

sub git_dir_latest {
	my ($self, $max) = @_;
	$$max = -1;
	my $pfx = "$self->{-inbox}->{mainrepo}/git";
	return unless -d $pfx;
	my $latest;
	opendir my $dh, $pfx or die "opendir $pfx: $!\n";
	while (defined(my $git_dir = readdir($dh))) {
		$git_dir =~ m!\A(\d+)\.git\z! or next;
		if ($1 > $$max) {
			$$max = $1;
			$latest = "$pfx/$git_dir";
		}
	}
	$latest;
}

sub importer {
	my ($self) = @_;
	my $im = $self->{im};
	if ($im) {
		if ($im->{bytes_added} < $self->{rotate_bytes}) {
			return $im;
		} else {
			$self->{im} = undef;
			$im->done;
			$im = undef;
			$self->checkpoint;
			my $git_dir = $self->git_init(++$self->{epoch_max});
			my $git = PublicInbox::Git->new($git_dir);
			return $self->import_init($git, 0);
		}
	}
	my $epoch = 0;
	my $max;
	my $latest = git_dir_latest($self, \$max);
	if (defined $latest) {
		my $git = PublicInbox::Git->new($latest);
		my $packed_bytes = $git->packed_bytes;
		if ($packed_bytes >= $self->{rotate_bytes}) {
			$epoch = $max + 1;
		} else {
			$self->{epoch_max} = $max;
			return $self->import_init($git, $packed_bytes);
		}
	}
	$self->{epoch_max} = $epoch;
	$latest = $self->git_init($epoch);
	$self->import_init(PublicInbox::Git->new($latest), 0);
}

sub import_init {
	my ($self, $git, $packed_bytes, $tmp) = @_;
	my $im = PublicInbox::Import->new($git, undef, undef, $self->{-inbox});
	$im->{bytes_added} = int($packed_bytes / $PACKING_FACTOR);
	$im->{want_object_info} = 1;
	$im->{lock_path} = undef;
	$im->{path_type} = 'v2';
	$self->{im} = $im unless $tmp;
	$im;
}

# XXX experimental
sub diff ($$$) {
	my ($mid, $cur, $new) = @_;
	use File::Temp qw(tempfile);

	my ($ah, $an) = tempfile('email-cur-XXXXXXXX', TMPDIR => 1);
	print $ah $cur->as_string or die "print: $!";
	close $ah or die "close: $!";
	my ($bh, $bn) = tempfile('email-new-XXXXXXXX', TMPDIR => 1);
	PublicInbox::Import::drop_unwanted_headers($new);
	print $bh $new->as_string or die "print: $!";
	close $bh or die "close: $!";
	my $cmd = [ qw(diff -u), $an, $bn ];
	print STDERR "# MID conflict <$mid>\n";
	my $pid = spawn($cmd, undef, { 1 => 2 });
	defined $pid or die "diff failed to spawn $!";
	waitpid($pid, 0) == $pid or die "diff did not finish";
	unlink($an, $bn);
}

sub get_blob ($$) {
	my ($self, $smsg) = @_;
	if (my $im = $self->{im}) {
		my $msg = $im->cat_blob($smsg->{blob});
		return $msg if $msg;
	}
	# older message, should be in alternates
	my $ibx = $self->{-inbox};
	$ibx->msg_by_smsg($smsg);
}

sub lookup_content {
	my ($self, $mime, $mid) = @_;
	my $over = $self->{over};
	my $cids = content_ids($mime);
	my ($id, $prev);
	while (my $smsg = $over->next_by_mid($mid, \$id, \$prev)) {
		my $msg = get_blob($self, $smsg);
		if (!defined($msg)) {
			warn "broken smsg for $mid\n";
			next;
		}
		my $cur = PublicInbox::MIME->new($msg);
		if (content_matches($cids, $cur)) {
			$smsg->{mime} = $cur;
			return $smsg;
		}


		# XXX DEBUG_DIFF is experimental and may be removed
		diff($mid, $cur, $mime) if $ENV{DEBUG_DIFF};
	}
	undef;
}

sub atfork_child {
	my ($self) = @_;
	my $fh = delete $self->{reindex_pipe};
	close $fh if $fh;
	if (my $parts = $self->{idx_parts}) {
		$_->atfork_child foreach @$parts;
	}
	if (my $im = $self->{im}) {
		$im->atfork_child;
	}
	die "unexpected mm" if $self->{mm};
	close $self->{bnote}->[0] or die "close bnote[0]: $!\n";
	$self->{bnote}->[1];
}

sub mark_deleted {
	my ($self, $D, $git, $oid) = @_;
	my $msgref = $git->cat_file($oid);
	my $mime = PublicInbox::MIME->new($$msgref);
	my $mids = mids($mime->header_obj);
	my $cid = content_id($mime);
	foreach my $mid (@$mids) {
		$D->{"$mid\0$cid"} = $oid;
	}
}

sub reindex_oid {
	my ($self, $mm_tmp, $D, $git, $oid, $regen, $reindex) = @_;
	my $len;
	my $msgref = $git->cat_file($oid, \$len);
	my $mime = PublicInbox::MIME->new($$msgref);
	my $mids = mids($mime->header_obj);
	my $cid = content_id($mime);

	# get the NNTP article number we used before, highest number wins
	# and gets deleted from mm_tmp;
	my $mid0;
	my $num = -1;
	my $del = 0;
	foreach my $mid (@$mids) {
		$del += delete($D->{"$mid\0$cid"}) ? 1 : 0;
		my $n = $mm_tmp->num_for($mid);
		if (defined $n && $n > $num) {
			$mid0 = $mid;
			$num = $n;
			$self->{mm}->mid_set($num, $mid0);
		}
	}
	if (!defined($mid0) && $regen && !$del) {
		$num = $$regen--;
		die "BUG: ran out of article numbers\n" if $num <= 0;
		my $mm = $self->{mm};
		foreach my $mid (reverse @$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";
			foreach my $mid (@$mids) {
				defined(my $n = $mm->num_for($mid)) or next;
				warn "#$n previously mapped for <$mid>\n";
			}
		}
	}

	if (!defined($mid0) || $del) {
		if (!defined($mid0) && $del) { # expected for deletes
			$num = $$regen--;
			$self->{mm}->num_highwater($num) unless $reindex;
			return
		}

		my $id = '<' . join('> <', @$mids) . '>';
		defined($mid0) or
			warn "Skipping $id, no article number found\n";
		if ($del && defined($mid0)) {
			warn "$id was deleted $del " .
				"time(s) but mapped to article #$num\n";
		}
		return;

	}
	$mm_tmp->mid_delete($mid0) or
		die "failed to delete <$mid0> for article #$num\n";

	$self->{over}->add_overview($mime, $len, $num, $oid, $mid0);
	my $nparts = $self->{partitions};
	my $part = $num % $nparts;
	my $idx = $self->idx_part($part);
	$idx->index_raw($len, $msgref, $num, $oid, $mid0, $mime);
	my $n = $self->{transact_bytes} += $len;
	if ($n > (PublicInbox::SearchIdx::BATCH_BYTES * $nparts)) {
		$git->cleanup;
		$mm_tmp->atfork_prepare;
		$self->done; # release lock
		# allow -watch or -mda to write...
		$self->idx_init; # reacquire lock
		$mm_tmp->atfork_parent;
	}
}

# only update last_commit for $i on reindex iff newer than current
sub update_last_commit {
	my ($self, $git, $i, $cmt) = @_;
	my $last = last_commit_part($self, $i);
	if (defined $last && is_ancestor($git, $last, $cmt)) {
		my @cmd = (qw(rev-list --count), "$last..$cmt");
		chomp(my $n = $git->qx(@cmd));
		return if $n ne '' && $n == 0;
	}
	last_commit_part($self, $i, $cmt);
}

sub git_dir_n ($$) { "$_[0]->{-inbox}->{mainrepo}/git/$_[1].git" }

sub last_commits {
	my ($self, $epoch_max) = @_;
	my $heads = [];
	for (my $i = $epoch_max; $i >= 0; $i--) {
		$heads->[$i] = last_commit_part($self, $i);
	}
	$heads;
}

*is_ancestor = *PublicInbox::SearchIdx::is_ancestor;

sub index_prepare {
	my ($self, $opts, $epoch_max, $ranges) = @_;
	my $regen_max = 0;
	my $head = $self->{-inbox}->{ref_head} || 'refs/heads/master';
	for (my $i = $epoch_max; $i >= 0; $i--) {
		die "already indexing!\n" if $self->{index_pipe};
		my $git_dir = git_dir_n($self, $i);
		-d $git_dir or next; # missing parts are fine
		my $git = PublicInbox::Git->new($git_dir);
		chomp(my $tip = $git->qx(qw(rev-parse -q --verify), $head));
		next if $?; # new repo
		my $range;
		if (defined(my $cur = $ranges->[$i])) {
			$range = "$cur..$tip";
			if (is_ancestor($git, $cur, $tip)) { # common case
				my $n = $git->qx(qw(rev-list --count), $range);
				chomp($n);
				if ($n == 0) {
					$ranges->[$i] = undef;
					next;
				}
			} else {
				warn <<"";
discontiguous range: $range
Rewritten history? (in $git_dir)

				my $base = $git->qx('merge-base', $tip, $cur);
				chomp $base;
				if ($base) {
					$range = "$base..$tip";
					warn "found merge-base: $base\n"
				} else {
					$range = $tip;
					warn <<"";
discarding history at $cur

				}
				warn <<"";
reindexing $git_dir starting at
$range

				$self->{"unindex-range.$i"} = "$base..$cur";
			}
		} else {
			$range = $tip; # all of it
		}
		$ranges->[$i] = $range;

		# can't use 'rev-list --count' if we use --diff-filter
		my $fh = $git->popen(qw(log --pretty=tformat:%H
				--no-notes --no-color --no-renames
				--diff-filter=AM), $range, '--', 'm');
		++$regen_max while <$fh>;
	}
	\$regen_max;
}

sub unindex_oid_remote {
	my ($self, $oid, $mid) = @_;
	$_->remote_remove($oid, $mid) foreach @{$self->{idx_parts}};
	$self->{over}->remove_oid($oid, $mid);
}

sub unindex_oid {
	my ($self, $git, $oid) = @_;
	my $msgref = $git->cat_file($oid);
	my $mime = PublicInbox::MIME->new($msgref);
	my $mids = mids($mime->header_obj);
	$mime = $msgref = undef;
	my $over = $self->{over};
	foreach my $mid (@$mids) {
		my %gone;
		my ($id, $prev);
		while (my $smsg = $over->next_by_mid($mid, \$id, \$prev)) {
			$gone{$smsg->{num}} = 1 if $oid eq $smsg->{blob};
			1; # continue
		}
		my $n = scalar keys %gone;
		next unless $n;
		if ($n > 1) {
			warn "BUG: multiple articles linked to $oid\n",
				join(',',sort keys %gone), "\n";
		}
		foreach my $num (keys %gone) {
			$self->{unindexed}->{$_}++;
			$self->{mm}->num_delete($num);
		}
		$self->unindex_oid_remote($oid, $mid);
	}
}

my $x40 = qr/[a-f0-9]{40}/;
sub unindex {
	my ($self, $opts, $git, $unindex_range) = @_;
	my $un = $self->{unindexed} ||= {}; # num => removal count
	my $before = scalar keys %$un;
	my @cmd = qw(log --raw -r
			--no-notes --no-color --no-abbrev --no-renames);
	my $fh = $self->{reindex_pipe} = $git->popen(@cmd, $unindex_range);
	while (<$fh>) {
		/\A:\d{6} 100644 $x40 ($x40) [AM]\tm$/o or next;
		$self->unindex_oid($git, $1);
	}
	delete $self->{reindex_pipe};
	$fh = undef;

	return unless $opts->{prune};
	my $after = scalar keys %$un;
	return if $before == $after;

	# ensure any blob can not longer be accessed via dumb HTTP
	PublicInbox::Import::run_die(['git', "--git-dir=$git->{git_dir}",
		qw(-c gc.reflogExpire=now gc --prune=all)]);
}

sub index_sync {
	my ($self, $opts) = @_;
	$opts ||= {};
	my $epoch_max;
	my $latest = git_dir_latest($self, \$epoch_max);
	return unless defined $latest;
	$self->idx_init; # acquire lock
	my $mm_tmp = $self->{mm}->tmp_clone;
	my $reindex = $opts->{reindex};
	my $ranges = $reindex ? [] : $self->last_commits($epoch_max);

	my $high = $self->{mm}->num_highwater();
	my $regen = $self->index_prepare($opts, $epoch_max, $ranges);
	$$regen += $high if $high;
	my $D = {}; # "$mid\0$cid" => $oid
	my @cmd = qw(log --raw -r --pretty=tformat:%H
			--no-notes --no-color --no-abbrev --no-renames);

	# work backwards through history
	my $last_commit = [];
	for (my $i = $epoch_max; $i >= 0; $i--) {
		my $git_dir = git_dir_n($self, $i);
		die "already reindexing!\n" if delete $self->{reindex_pipe};
		-d $git_dir or next; # missing parts are fine
		my $git = PublicInbox::Git->new($git_dir);
		my $unindex = delete $self->{"unindex-range.$i"};
		$self->unindex($opts, $git, $unindex) if $unindex;
		defined(my $range = $ranges->[$i]) or next;
		my $fh = $self->{reindex_pipe} = $git->popen(@cmd, $range);
		my $cmt;
		while (<$fh>) {
			if (/\A$x40$/o && !defined($cmt)) {
				chomp($cmt = $_);
			} elsif (/\A:\d{6} 100644 $x40 ($x40) [AM]\tm$/o) {
				$self->reindex_oid($mm_tmp, $D, $git, $1,
						$regen, $reindex);
			} elsif (/\A:\d{6} 100644 $x40 ($x40) [AM]\td$/o) {
				$self->mark_deleted($D, $git, $1);
			}
		}
		$fh = undef;
		delete $self->{reindex_pipe};
		$self->update_last_commit($git, $i, $cmt) if defined $cmt;
	}

	# unindex is required for leftovers if "deletes" affect messages
	# in a previous fetch+index window:
	if (scalar keys %$D) {
		my $git = $self->{-inbox}->git;
		$self->unindex_oid($git, $_) for values %$D;
		$git->cleanup;
	}
	$self->done;
}

1;
debug log:

solving 222df5c ...
found 222df5c in https://80x24.org/public-inbox.git

user/dev discussion of public-inbox itself

Archives are clonable:
	git clone --mirror http://public-inbox.org/meta
	git clone --mirror http://czquwvybam4bgbro.onion/meta
	git clone --mirror http://hjrcffqmbrq6wope.onion/meta
	git clone --mirror http://ou63pmih66umazou.onion/meta

Example config snippet for mirrors

Newsgroups are available over NNTP:
	nntp://news.public-inbox.org/inbox.comp.mail.public-inbox.meta
	nntp://ou63pmih66umazou.onion/inbox.comp.mail.public-inbox.meta
	nntp://czquwvybam4bgbro.onion/inbox.comp.mail.public-inbox.meta
	nntp://hjrcffqmbrq6wope.onion/inbox.comp.mail.public-inbox.meta
	nntp://news.gmane.org/gmane.mail.public-inbox.general

 note: .onion URLs require Tor: https://www.torproject.org/

AGPL code for this site: git clone https://public-inbox.org/public-inbox.git