search: add comments wrt codesearch, reduce ops

Add some comments about various usages of xdb_shards_flat and
mset since the addition of CodeSearch (and other search things)
subclassing it may become confusing.

Since we're in the area, we can also avoid an extra hash
lookups/initializations and reduce Perl ops in various places.

1 files changed, 16 insertions, 20 deletions

diff --git a/lib/PublicInbox/Search.pm b/lib/PublicInbox/Search.pm
index 6c3d9f93..6986cb88 100644
--- a/lib/PublicInbox/Search.pm
+++ b/lib/PublicInbox/Search.pm
@@ -209,19 +209,19 @@ sub xdb_shards_flat ($) {
         my (@xdb, $slow_phrase);
         load_xapian();
         $self->{qp_flags} //= $QP_FLAGS;
-        if ($xpfx =~ m!/xapian[0-9]+\z!) {
+        if ($xpfx =~ m!/xapian[0-9]+\z!) { # v1
                 @xdb = ($X{Database}->new($xpfx));
                 $self->{qp_flags} |= FLAG_PHRASE() if !-f "$xpfx/iamchert";
-        } else {
+        } else { # v2, eidx, cidx
                 opendir(my $dh, $xpfx) or return (); # not initialized yet
                 # We need numeric sorting so shard[0] is first for reading
                 # Xapian metadata, if needed
                 my $last = max(grep(/\A[0-9]+\z/, readdir($dh))) // return ();
-                for (0..$last) {
-                        my $shard_dir = "$self->{xpfx}/$_";
-                        push @xdb, $X{Database}->new($shard_dir);
+                @xdb = map {
+                        my $shard_dir = "$xpfx/$_";
                         $slow_phrase ||= -f "$shard_dir/iamchert";
-                }
+                        $X{Database}->new($shard_dir);
+                } (0..$last);
                 $self->{qp_flags} |= FLAG_PHRASE() if !$slow_phrase;
         }
         @xdb;
@@ -371,31 +371,28 @@ sub query_approxidate {
         date_parse_finalize($git, $to_parse, $_[2]) if $to_parse;
 }
 
-# read-only
+# read-only, for mail only (codesearch has different rules)
 sub mset {
-        my ($self, $query_string, $opt) = @_;
-        $opt ||= {};
+        my ($self, $qry_str, $opt) = @_;
         my $qp = $self->{qp} //= $self->qparse_new;
-        my $query = $qp->parse_query($query_string, $self->{qp_flags});
+        my $qry = $qp->parse_query($qry_str, $self->{qp_flags});
         if (defined(my $eidx_key = $opt->{eidx_key})) {
-                $query = $X{Query}->new(OP_FILTER(), $query, 'O'.$eidx_key);
+                $qry = $X{Query}->new(OP_FILTER(), $qry, 'O'.$eidx_key);
         }
         if (defined(my $uid_range = $opt->{uid_range})) {
                 my $range = $X{Query}->new(OP_VALUE_RANGE(), UID,
                                         sortable_serialise($uid_range->[0]),
                                         sortable_serialise($uid_range->[1]));
-                $query = $X{Query}->new(OP_FILTER(), $query, $range);
+                $qry = $X{Query}->new(OP_FILTER(), $qry, $range);
         }
         if (defined(my $tid = $opt->{threadid})) {
                 $tid = sortable_serialise($tid);
-                $query = $X{Query}->new(OP_FILTER(), $query,
-                                $X{Query}->new(OP_VALUE_RANGE(), THREADID, $tid, $tid));
+                $qry = $X{Query}->new(OP_FILTER(), $qry,
+                        $X{Query}->new(OP_VALUE_RANGE(), THREADID, $tid, $tid));
         }
 
-        my $xdb = xdb($self);
-        my $enq = $X{Enquire}->new($xdb);
-        $enq->set_query($query);
-        $opt ||= {};
+        my $enq = $X{Enquire}->new(xdb($self));
+        $enq->set_query($qry);
         my $rel = $opt->{relevance} // 0;
         if ($rel == -2) { # ORDER BY docid/UID (highest first)
                 $enq->set_weighting_scheme($X{BoolWeight}->new);
@@ -411,9 +408,8 @@ sub mset {
 
         # `lei q -t / --threads' or JMAP collapseThreads; but don't collapse
         # on `-tt' ({threads} > 1) which sets the Flagged|Important keyword
-        if (($opt->{threads} // 0) == 1 && has_threadid($self)) {
+        (($opt->{threads} // 0) == 1 && has_threadid($self)) and
                 $enq->set_collapse_key(THREADID);
-        }
         retry_reopen($self, \&enquire_once, $enq,
                         $opt->{offset} || 0, $opt->{limit} || 50);
 }