view: perform highlighting for space-prefixed diffs

"git format-patch --interdiff" and similar can prefix diffs
with leading white space.  Teach our diff parser to account
for it and set appropriate CSS classes for them.

1 files changed, 6 insertions, 0 deletions

diff --git a/lib/PublicInbox/ViewDiff.pm b/lib/PublicInbox/ViewDiff.pm
index 6b8d9437..e9cfc368 100644
--- a/lib/PublicInbox/ViewDiff.pm
+++ b/lib/PublicInbox/ViewDiff.pm
@@ -141,8 +141,14 @@ sub flush_diff ($$$) {
         my $spfx = $ctx->{-spfx};
         my $state = DSTATE_INIT;
         my $dctx = { Q => '' }; # {}, keys: oid_a, oid_b, path_a, path_b
+        my $dpfx = $ctx->{-dpfx}; # leading spaces for interdiff
+        my $dpfx_re = qr/\A$dpfx/ if defined $dpfx;
 
         foreach my $s (@$diff) {
+                if (defined($dpfx)) {
+                        $s =~ s/$dpfx_re//;
+                        $$dst .= $dpfx;
+                }
                 if ($s =~ /^---$/) {
                         to_state($dst, $state, DSTATE_STAT);
                         $$dst .= $s;