[PATCH 02/11] indexheader: deduplicate common values

[Eric Wong <e@80x24.org>]

Since we plan on sharing IndexHeader across multiple inboxes for
large installations with thousands of inboxes, it makes sense to
deduplicate the values to save some memory at the cost of
increased startup time.
---
 lib/PublicInbox/IndexHeader.pm | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/lib/PublicInbox/IndexHeader.pm b/lib/PublicInbox/IndexHeader.pm
index 53e9373b..07827959 100644
--- a/lib/PublicInbox/IndexHeader.pm
+++ b/lib/PublicInbox/IndexHeader.pm
@@ -17,7 +17,8 @@ sub extra_indexer_new_common ($$$$) {
 	my ($self, $spec, $pfx, $query) = @_;
 	$pfx =~ /\A[a-z][a-z0-9]*\z/ or
 		warn "W: non-word prefix in `$spec' not searchable\n";
-	$self->{prefix} = $pfx;
+	my %dedupe = ($pfx => undef);
+	($self->{prefix}) = keys %dedupe;
 	my %params = map {
 		my ($k, $v) = split /=/, uri_unescape($_), 2;
 		($k, $v // '');
@@ -25,7 +26,8 @@ sub extra_indexer_new_common ($$$$) {
 	my $xpfx = delete($params{index_prefix}) // "X\U$pfx";
 	$xpfx =~ /\A[A-Z][A-Z0-9]*\z/ or die
 		die "E: `index_prefix' in `$spec' must be ALL CAPS\n";
-	$self->{xprefix} = $xpfx;
+	%dedupe = ($xpfx => undef);
+	($self->{xprefix}) = keys %dedupe;
 	\%params;
 }
 
@@ -34,14 +36,18 @@ sub new {
 	my ($type, $pfx, $header, $query) = split /:/, $spec, 4;
 	$pfx // die "E: `$spec' has no user prefix\n";
 	$header // die "E: `$spec' has no mail header\n";
+	$T2IDX{$type} // die
+		"E: `$type' not supported in $spec, must be one of: ",
+		join(', ', sort keys %T2IDX), "\n";
+	my %dedupe = ($type => undef);
+	($type) = keys %dedupe;
+	%dedupe = ($header => undef);
+	($header) = keys %dedupe;
 	my $self = bless { header => $header, type => $type }, $cls;
 	my $params = extra_indexer_new_common $self, $spec, $pfx, $query;
 	$self->{hdr_method} = delete $params->{raw} ? 'header_raw' : 'header';
 	my @k = keys %$params;
 	warn "W: unknown params in `$spec': ", join(', ', @k), "\n" if @k;
-	$T2IDX{$type} // die
-		"E: `$type' not supported in $spec, must be one of: ",
-		join(', ', sort keys %T2IDX), "\n";
 	$self;
 }