ui-diff: Teach diffstat to obey path limit

Also indicate in the diffstat header if a path limit is in effect.

Signed-off-by: Johan Herland <johan@herland.net>
Signed-off-by: Lars Hjemli <hjemli@gmail.com>
diff --git a/ui-diff.c b/ui-diff.c
index a92a768..fb836df 100644
--- a/ui-diff.c
+++ b/ui-diff.c
@@ -154,17 +154,19 @@
 }
 
 void cgit_print_diffstat(const unsigned char *old_sha1,
-			 const unsigned char *new_sha1)
+			 const unsigned char *new_sha1, const char *prefix)
 {
 	int i;
 
 	html("<div class='diffstat-header'>");
 	cgit_diff_link("Diffstat", NULL, NULL, ctx.qry.head, ctx.qry.sha1,
 		       ctx.qry.sha2, NULL, 0);
+	if (prefix)
+		htmlf(" (limited to '%s')", prefix);
 	html("</div>");
 	html("<table summary='diffstat' class='diffstat'>");
 	max_changes = 0;
-	cgit_diff_tree(old_sha1, new_sha1, inspect_filepair, NULL);
+	cgit_diff_tree(old_sha1, new_sha1, inspect_filepair, prefix);
 	for(i = 0; i<files; i++)
 		print_fileinfo(&items[i]);
 	html("</table>");
@@ -338,7 +340,7 @@
 		use_ssdiff = 1;
 
 	print_ssdiff_link();
-	cgit_print_diffstat(old_rev_sha1, new_rev_sha1);
+	cgit_print_diffstat(old_rev_sha1, new_rev_sha1, prefix);
 
 	if (use_ssdiff) {
 		html("<table summary='ssdiff' class='ssdiff'>");