[PATCH] view: perform highlighting for space-prefixed diffs

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

"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.
---
 lib/PublicInbox/View.pm     | 4 +++-
 lib/PublicInbox/ViewDiff.pm | 6 ++++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/lib/PublicInbox/View.pm b/lib/PublicInbox/View.pm
index 47a2046..35e171b 100644
--- a/lib/PublicInbox/View.pm
+++ b/lib/PublicInbox/View.pm
@@ -568,7 +568,9 @@ sub add_text_body {
 	# always support diff-highlighting, but we can't linkify hunk
 	# headers for solver unless some coderepo are configured:
 	my $diff;
-	if ($s =~ /^(?:diff|---|\+{3}) /ms) {
+	if ($s =~ /^([ \t]*)(?:diff|---|\+{3}) /ms) {
+		$ctx->{-dpfx} = $1 if $1; # for format-patch --interdiff output
+
 		# diffstat anchors do not link across attachments or messages:
 		$idx[0] = $upfx . $idx[0] if $upfx ne '';
 		$ctx->{-apfx} = join('/', @idx);
diff --git a/lib/PublicInbox/ViewDiff.pm b/lib/PublicInbox/ViewDiff.pm
index 6b8d943..e9cfc36 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;
-- 
EW