filter: add fprintf_filter function

This stops the code in cgit.c::print_repo needing to inspect the
cgit_filter structure, meaning that we can abstract out different filter
types that will have different fields that need to be printed.

Signed-off-by: John Keeping <john@keeping.me.uk>

cgit.c

@@ -706,11 +706,11 @@ static void print_repo(FILE *f, struct cgit_repo *repo)
 	fprintf(f, "repo.enable-log-linecount=%d\n",
 	        repo->enable_log_linecount);
 	if (repo->about_filter && repo->about_filter != ctx.cfg.about_filter)
-		fprintf(f, "repo.about-filter=%s\n", repo->about_filter->cmd);
+		cgit_fprintf_filter(repo->about_filter, f, "repo.about-filter=");
 	if (repo->commit_filter && repo->commit_filter != ctx.cfg.commit_filter)
-		fprintf(f, "repo.commit-filter=%s\n", repo->commit_filter->cmd);
+		cgit_fprintf_filter(repo->commit_filter, f, "repo.commit-filter=");
 	if (repo->source_filter && repo->source_filter != ctx.cfg.source_filter)
-		fprintf(f, "repo.source-filter=%s\n", repo->source_filter->cmd);
+		cgit_fprintf_filter(repo->source_filter, f, "repo.source-filter=");
 	if (repo->snapshots != ctx.cfg.snapshots) {
 		char *tmp = build_snapshot_setting(repo->snapshots);
 		fprintf(f, "repo.snapshots=%s\n", tmp ? tmp : "");

cgit.h

@@ -345,6 +345,7 @@ extern int cgit_parse_snapshots_mask(const char *str);
 
 extern int cgit_open_filter(struct cgit_filter *filter, ...);
 extern int cgit_close_filter(struct cgit_filter *filter);
+extern void cgit_fprintf_filter(struct cgit_filter *filter, FILE *f, const char *prefix);
 extern struct cgit_filter *cgit_new_filter(const char *cmd, filter_type filtertype);
 
 extern void cgit_prepare_repo_env(struct cgit_repo * repo);

filter.c

@@ -63,6 +63,11 @@ done:
 
 }
 
+void cgit_fprintf_filter(struct cgit_filter *filter, FILE *f, const char *prefix)
+{
+	fprintf(f, "%s%s\n", prefix, filter->cmd);
+}
+
 struct cgit_filter *cgit_new_filter(const char *cmd, filter_type filtertype)
 {
 	struct cgit_filter *f;