Expand `module-link` placeholders outside printf

1 file changed, 40 insertions, 2 deletions

diff --git a/source/ui-shared.c b/source/ui-shared.c
index 1b65a7f..125a235 100644
--- a/source/ui-shared.c
+++ b/source/ui-shared.c
@@ -616,6 +616,39 @@ static struct string_list_item *lookup_path(struct string_list *list,
 	return NULL;
 }
 
+/*
+ * Expand the %s placeholders in a module-link template and emit the result as
+ * an attribute value. The template is never handed to printf: a repository can
+ * supply its own through a repo-local cgitrc, and a surplus conversion would
+ * then read past the argument list.
+ */
+static void html_module_link(const char *tmpl, const char **args, int nargs)
+{
+	struct strbuf sb = STRBUF_INIT;
+	int used = 0;
+
+	while (*tmpl) {
+		if (*tmpl != '%') {
+			strbuf_addch(&sb, *tmpl++);
+			continue;
+		}
+		tmpl++;
+		if (*tmpl == '%') {
+			strbuf_addch(&sb, '%');
+			tmpl++;
+		} else if (*tmpl == 's' && used < nargs) {
+			strbuf_addstr(&sb, args[used++]);
+			tmpl++;
+		} else {
+			// Anything else is not a placeholder this template can
+			// fill, so keep it verbatim rather than dropping it.
+			strbuf_addch(&sb, '%');
+		}
+	}
+	html_attr(sb.buf);
+	strbuf_release(&sb);
+}
+
 void cgit_submodule_link(const char *class, char *path, const char *rev)
 {
 	struct string_list *list;
@@ -641,14 +674,19 @@ void cgit_submodule_link(const char *class, char *path, const char *rev)
 			htmlf("class='%s' ", class);
 		html("href='");
 		if (item) {
-			html_attrf(item->util, rev);
+			// A per-path template names only the submodule commit.
+			const char *args[] = { rev };
+			html_module_link(item->util, args, 1);
 		} else {
+			const char *args[2];
 			dir = strrchr(path, '/');
 			if (dir)
 				dir++;
 			else
 				dir = path;
-			html_attrf(ctx.repo->module_link, dir, rev);
+			args[0] = dir;
+			args[1] = rev;
+			html_module_link(ctx.repo->module_link, args, 2);
 		}
 		html("'>");
 		html_txt(path);