search: use one git-rev-parse process for all dates

This is necessary to avoid slowdowns with pathological cases
with many dates in the query, since each rev-parse invocation
takes ~5ms.

This is immeasurably slower with one open-ended range, but
already faster with any closed range featuring two dates which
require parsing via git.

1 files changed, 4 insertions, 2 deletions

diff --git a/lib/PublicInbox/Git.pm b/lib/PublicInbox/Git.pm
index 9207962b..ac7ff267 100644
--- a/lib/PublicInbox/Git.pm
+++ b/lib/PublicInbox/Git.pm
@@ -377,8 +377,10 @@ sub qx {
 }
 
 sub date_parse {
-        my $d = $_[0]->qx('rev-parse', "--since=$_[1]");
-        substr($d, length('--max-age='), -1)
+        my $self = shift;
+        map {
+                substr($_, length('--max-age='), -1)
+        } $self->qx('rev-parse', map { "--since=$_" } @_);
 }
 
 # check_async and cat_async may trigger the other, so ensure they're