lei_mirror+fetch: don't slurp `git show-ref' output

While uncommon, some git repos have hundreds of thousands of
refs and slurping that output into memory can bloat the heap.
Introduce a sha_all sub in PublicInbox::SHA to loop until EOF
and rely on autodie for checking sysread errors.

1 files changed, 2 insertions, 2 deletions

diff --git a/lib/PublicInbox/Fetch.pm b/lib/PublicInbox/Fetch.pm
index 6e9b1e94..e41dd448 100644
--- a/lib/PublicInbox/Fetch.pm
+++ b/lib/PublicInbox/Fetch.pm
@@ -10,6 +10,7 @@ use PublicInbox::Admin;
 use PublicInbox::LEI;
 use PublicInbox::LeiCurl;
 use PublicInbox::LeiMirror;
+use PublicInbox::SHA qw(sha_all);
 use File::Temp ();
 
 sub new { bless {}, __PACKAGE__ }
@@ -92,9 +93,8 @@ sub do_manifest ($$$) {
 
 sub get_fingerprint2 {
         my ($git_dir) = @_;
-        require PublicInbox::SHA;
         my $rd = popen_rd([qw(git show-ref)], undef, { -C => $git_dir });
-        PublicInbox::SHA::sha256(do { local $/; <$rd> });
+        sha_all(256, $rd)->digest; # ignore show-ref errors
 }
 
 sub writable_dir ($) {