# Copyright (C) 2015-2020 all contributors
# License: AGPL-3.0+
# based on notmuch, but with no concept of folders, files or flags
#
# Read-only search interface for use by the web and NNTP interfaces
package PublicInbox::Search;
use strict;
use parent qw(Exporter);
our @EXPORT_OK = qw(mdocid);
# values for searching, changing the numeric value breaks
# compatibility with old indices (so don't change them it)
use constant {
TS => 0, # Received: header in Unix time (IMAP INTERNALDATE)
YYYYMMDD => 1, # Date: header for searching in the WWW UI
DT => 2, # Date: YYYYMMDDHHMMSS
# added for public-inbox 1.6.0+
BYTES => 3, # IMAP RFC822.SIZE
UID => 4, # IMAP UID == NNTP article number == Xapian docid
THREADID => 5, # RFC 8474, RFC 8621
# TODO
# REPLYCNT => ?, # IMAP ANSWERED
# SCHEMA_VERSION history
# 0 - initial
# 1 - subject_path is lower-cased
# 2 - subject_path is id_compress in the index, only
# 3 - message-ID is compressed if it includes '%' (hack!)
# 4 - change "Re: " normalization, avoid circular Reference ghosts
# 5 - subject_path drops trailing '.'
# 6 - preserve References: order in document data
# 7 - remove references and inreplyto terms
# 8 - remove redundant/unneeded document data
# 9 - disable Message-ID compression (SHA-1)
# 10 - optimize doc for NNTP overviews
# 11 - merge threads when vivifying ghosts
# 12 - change YYYYMMDD value column to numeric
# 13 - fix threading for empty References/In-Reply-To
# (commit 83425ef12e4b65cdcecd11ddcb38175d4a91d5a0)
# 14 - fix ghost root vivification
# 15 - see public-inbox-v2-format(5)
# further bumps likely unnecessary, we'll suggest in-place
# "--reindex" use for further fixes and tweaks:
#
# public-inbox v1.5.0 adds (still SCHEMA_VERSION=15):
# * "lid:" and "l:" for List-Id searches
#
# v1.6.0 adds BYTES, UID and THREADID values
SCHEMA_VERSION => 15,
};
use PublicInbox::Smsg;
use PublicInbox::Over;
my $QP_FLAGS;
our %X = map { $_ => 0 } qw(BoolWeight Database Enquire QueryParser Stem);
our $Xap; # 'Search::Xapian' or 'Xapian'
my $NVRP; # '$Xap::'.('NumberValueRangeProcessor' or 'NumberRangeProcessor')
my $ENQ_ASCENDING;
sub load_xapian () {
return 1 if defined $Xap;
# n.b. PI_XAPIAN is intended for development use only. We still
# favor Search::Xapian since that's what's available in current
# Debian stable (10.x) and derived distros.
for my $x (($ENV{PI_XAPIAN} // 'Search::Xapian'), 'Xapian') {
eval "require $x";
next if $@;
$x->import(qw(:standard));
$Xap = $x;
# `version_string' was added in Xapian 1.1
my $xver = eval('v'.eval($x.'::version_string()')) //
eval('v'.eval($x.'::xapian_version_string()'));
# NumberRangeProcessor was added in Xapian 1.3.6,
# NumberValueRangeProcessor was removed for 1.5.0+,
# favor the older /Value/ variant since that's what our
# (currently) preferred Search::Xapian supports
$NVRP = $x.'::'.($x eq 'Xapian' && $xver ge v1.5 ?
'NumberRangeProcessor' : 'NumberValueRangeProcessor');
$X{$_} = $Xap.'::'.$_ for (keys %X);
# ENQ_ASCENDING doesn't seem exported by SWIG Xapian.pm,
# so lets hope this part of the ABI is stable because it's
# just an integer:
$ENQ_ASCENDING = $x eq 'Xapian' ?
1 : Search::Xapian::ENQ_ASCENDING();
# for Smsg:
*PublicInbox::Smsg::sortable_unserialise =
$Xap.'::sortable_unserialise';
# n.b. FLAG_PURE_NOT is expensive not suitable for a public
# website as it could become a denial-of-service vector
# FLAG_PHRASE also seems to cause performance problems chert
# (and probably earlier Xapian DBs). glass seems fine...
# TODO: make this an option, maybe?
# or make indexlevel=medium as default
$QP_FLAGS = FLAG_PHRASE() | FLAG_BOOLEAN() | FLAG_LOVEHATE() |
FLAG_WILDCARD();
return 1;
}
undef;
}
# This is English-only, everything else is non-standard and may be confused as
# a prefix common in patch emails
our $LANG = 'english';
# note: the non-X term prefix allocations are shared with
# Xapian omega, see xapian-applications/omega/docs/termprefixes.rst
my %bool_pfx_external = (
mid => 'Q', # Message-ID (full/exact), this is mostly uniQue
lid => 'G', # newsGroup (or similar entity), just inside <>
dfpre => 'XDFPRE',
dfpost => 'XDFPOST',
dfblob => 'XDFPRE XDFPOST',
);
my $non_quoted_body = 'XNQ XDFN XDFA XDFB XDFHH XDFCTX XDFPRE XDFPOST';
my %prob_prefix = (
# for mairix compatibility
s => 'S',
m => 'XM', # 'mid:' (bool) is exact, 'm:' (prob) can do partial
l => 'XL', # 'lid:' (bool) is exact, 'l:' (prob) can do partial
f => 'A',
t => 'XTO',
tc => 'XTO XCC',
c => 'XCC',
tcf => 'XTO XCC A',
a => 'XTO XCC A',
b => $non_quoted_body . ' XQUOT',
bs => $non_quoted_body . ' XQUOT S',
n => 'XFN',
q => 'XQUOT',
nq => $non_quoted_body,
dfn => 'XDFN',
dfa => 'XDFA',
dfb => 'XDFB',
dfhh => 'XDFHH',
dfctx => 'XDFCTX',
# default:
'' => 'XM S A XQUOT XFN ' . $non_quoted_body,
);
# not documenting m: and mid: for now, the using the URLs works w/o Xapian
# not documenting lid: for now, either, it is probably redundant with l:,
# especially since we don't offer boolean searches for To/Cc/From
# headers, either
our @HELP = (
's:' => 'match within Subject e.g. s:"a quick brown fox"',
'd:' => < < 'match within message body, including text attachments',
'nq:' => 'match non-quoted text within message body',
'q:' => 'match quoted text within message body',
'n:' => 'match filename of attachment(s)',
't:' => 'match within the To header',
'c:' => 'match within the Cc header',
'f:' => 'match within the From header',
'a:' => 'match within the To, Cc, and From headers',
'tc:' => 'match within the To and Cc headers',
'l:' => 'match contents of the List-Id header',
'bs:' => 'match within the Subject and body',
'dfn:' => 'match filename from diff',
'dfa:' => 'match diff removed (-) lines',
'dfb:' => 'match diff added (+) lines',
'dfhh:' => 'match diff hunk header context (usually a function name)',
'dfctx:' => 'match diff context lines',
'dfpre:' => 'match pre-image git blob ID',
'dfpost:' => 'match post-image git blob ID',
'dfblob:' => 'match either pre or post-image git blob ID',
);
chomp @HELP;
sub xdir ($;$) {
my ($self, $rdonly) = @_;
if ($rdonly || !defined($self->{shard})) {
$self->{xpfx};
} else { # v2 only:
"$self->{xpfx}/$self->{shard}";
}
}
sub _xdb ($) {
my ($self) = @_;
my $dir = xdir($self, 1);
my ($xdb, $slow_phrase);
my $qpf = \($self->{qp_flags} ||= $QP_FLAGS);
if ($self->{ibx_ver} >= 2) {
my @xdb;
opendir(my $dh, $dir) or return; # not initialized yet
# We need numeric sorting so shard[0] is first for reading
# Xapian metadata, if needed
for (sort { $a <=> $b } grep(/\A[0-9]+\z/, readdir($dh))) {
my $shard_dir = "$dir/$_";
if (-d $shard_dir && -r _) {
push @xdb, $X{Database}->new($shard_dir);
$slow_phrase ||= -f "$shard_dir/iamchert";
} else { # gaps from missing epochs throw off mdocid()
warn "E: $shard_dir missing or unreadable\n";
return;
}
}
$self->{nshard} = scalar(@xdb);
$xdb = shift @xdb;
$xdb->add_database($_) for @xdb;
} else {
$slow_phrase = -f "$dir/iamchert";
$xdb = $X{Database}->new($dir);
}
$$qpf |= FLAG_PHRASE() unless $slow_phrase;
$xdb;
}
# v2 Xapian docids don't conflict, so they're identical to
# NNTP article numbers and IMAP UIDs.
# https://trac.xapian.org/wiki/FAQ/MultiDatabaseDocumentID
sub mdocid {
my ($nshard, $mitem) = @_;
my $docid = $mitem->get_docid;
int(($docid - 1) / $nshard) + 1;
}
sub mset_to_artnums {
my ($self, $mset) = @_;
my $nshard = $self->{nshard} // 1;
[ map { mdocid($nshard, $_) } $mset->items ];
}
sub xdb ($) {
my ($self) = @_;
$self->{xdb} ||= do {
load_xapian();
_xdb($self);
};
}
sub xpfx_init ($) {
my ($self) = @_;
if ($self->{ibx_ver} == 1) {
$self->{xpfx} .= '/public-inbox/xapian' . SCHEMA_VERSION;
} else {
$self->{xpfx} .= '/xap'.SCHEMA_VERSION;
}
}
sub new {
my ($class, $ibx) = @_;
ref $ibx or die "BUG: expected PublicInbox::Inbox object: $ibx";
my $self = bless {
xpfx => $ibx->{inboxdir}, # for xpfx_init
altid => $ibx->{altid},
ibx_ver => $ibx->version,
}, $class;
xpfx_init($self);
my $dir = xdir($self, 1);
$self->{over_ro} = PublicInbox::Over->new("$dir/over.sqlite3");
$self;
}
sub reopen {
my ($self) = @_;
if (my $xdb = $self->{xdb}) {
$xdb->reopen;
}
$self; # make chaining easier
}
# read-only
sub query {
my ($self, $query_string, $opts) = @_;
$opts ||= {};
if ($query_string eq '' && !$opts->{mset}) {
$self->{over_ro}->recent($opts);
} else {
my $qp = $self->{qp} //= qparse_new($self);
my $qp_flags = $self->{qp_flags};
my $query = $qp->parse_query($query_string, $qp_flags);
$opts->{relevance} = 1 unless exists $opts->{relevance};
_do_enquire($self, $query, $opts);
}
}
sub retry_reopen {
my ($self, $cb, $arg) = @_;
for my $i (1..10) {
if (wantarray) {
my @ret;
eval { @ret = $cb->($arg) };
return @ret unless $@;
} else {
my $ret;
eval { $ret = $cb->($arg) };
return $ret unless $@;
}
# Exception: The revision being read has been discarded -
# you should call Xapian::Database::reopen()
if (ref($@) =~ /\bDatabaseModifiedError\b/) {
warn "reopen try #$i on $@\n";
reopen($self);
} else {
# let caller decide how to spew, because ExtMsg queries
# get wonky and trigger:
# "something terrible happened at .../Xapian/Enquire.pm"
die;
}
}
die "Too many Xapian database modifications in progress\n";
}
sub _do_enquire {
my ($self, $query, $opts) = @_;
retry_reopen($self, \&_enquire_once, [ $self, $query, $opts ]);
}
# returns true if all docs have the THREADID value
sub has_threadid ($) {
my ($self) = @_;
(xdb($self)->get_metadata('has_threadid') // '') eq '1';
}
sub _enquire_once { # retry_reopen callback
my ($self, $query, $opts) = @{$_[0]};
my $xdb = xdb($self);
my $enquire = $X{Enquire}->new($xdb);
$enquire->set_query($query);
$opts ||= {};
my $desc = !$opts->{asc};
if (($opts->{mset} || 0) == 2) { # mset == 2: ORDER BY docid/UID
$enquire->set_docid_order($ENQ_ASCENDING);
$enquire->set_weighting_scheme($X{BoolWeight}->new);
} elsif ($opts->{relevance}) {
$enquire->set_sort_by_relevance_then_value(TS, $desc);
} else {
$enquire->set_sort_by_value_then_relevance(TS, $desc);
}
# `mairix -t / --threads' or JMAP collapseThreads
if ($opts->{thread} && has_threadid($self)) {
$enquire->set_collapse_key(THREADID);
}
my $offset = $opts->{offset} || 0;
my $limit = $opts->{limit} || 50;
my $mset = $enquire->get_mset($offset, $limit);
return $mset if $opts->{mset};
my $nshard = $self->{nshard} // 1;
my $i = 0;
my %order = map { mdocid($nshard, $_) => ++$i } $mset->items;
my @msgs = sort {
$order{$a->{num}} <=> $order{$b->{num}}
} @{$self->{over_ro}->get_all(keys %order)};
wantarray ? ($mset->get_matches_estimated, \@msgs) : \@msgs;
}
# read-write
sub stemmer { $X{Stem}->new($LANG) }
# read-only
sub qparse_new ($) {
my ($self) = @_;
my $xdb = xdb($self);
my $qp = $X{QueryParser}->new;
$qp->set_default_op(OP_AND());
$qp->set_database($xdb);
$qp->set_stemmer(stemmer($self));
$qp->set_stemming_strategy(STEM_SOME());
my $cb = $qp->can('set_max_wildcard_expansion') //
$qp->can('set_max_expansion'); # Xapian 1.5.0+
$cb->($qp, 100);
$cb = $qp->can('add_valuerangeprocessor') //
$qp->can('add_rangeprocessor'); # Xapian 1.5.0+
$cb->($qp, $NVRP->new(YYYYMMDD, 'd:'));
$cb->($qp, $NVRP->new(DT, 'dt:'));
# for IMAP, undocumented for WWW and may be split off go away
$cb->($qp, $NVRP->new(BYTES, 'bytes:'));
$cb->($qp, $NVRP->new(TS, 'ts:'));
$cb->($qp, $NVRP->new(UID, 'uid:'));
while (my ($name, $prefix) = each %bool_pfx_external) {
$qp->add_boolean_prefix($name, $_) foreach split(/ /, $prefix);
}
# we do not actually create AltId objects,
# just parse the spec to avoid the extra DB handles for now.
if (my $altid = $self->{altid}) {
my $user_pfx = $self->{-user_pfx} = [];
for (@$altid) {
# $_ = 'serial:gmane:/path/to/gmane.msgmap.sqlite3'
# note: Xapian supports multibyte UTF-8, /^[0-9]+$/,
# and '_' with prefixes matching \w+
/\Aserial:(\w+):/ or next;
my $pfx = $1;
push @$user_pfx, "$pfx:", < XGMANE
$qp->add_boolean_prefix($pfx, 'X'.uc($pfx));
}
chomp @$user_pfx;
}
while (my ($name, $prefix) = each %prob_prefix) {
$qp->add_prefix($name, $_) foreach split(/ /, $prefix);
}
$qp;
}
sub help {
my ($self) = @_;
$self->{qp} //= qparse_new($self); # parse altids
my @ret = @HELP;
if (my $user_pfx = $self->{-user_pfx}) {
push @ret, @$user_pfx;
}
\@ret;
}
1;