til_settings: add some settings and desc path printers

These print to a stdio FILE*, which for now is harmless since
setup_interactively() will be the only consumer (... for now).

If one needed the path in a buffer, they could use
open_memstream() and pass that FILE* to the printers.  And since
commit 40feb61 there's already a dependency on the function, but
it's icky to dig deeper into that portability trap.

Although it seemed like rototiller actually compiled on MacOS at
Gene's house, so maybe open_memstream() isn't as problematic as
it once was.

Anywhow, this commit only adds the path printing helpers, nothing
is using them yet.

2 files changed, 72 insertions, 0 deletions

diff --git a/src/til_settings.c b/src/til_settings.c
index e42aae8..510dbaf 100644
--- a/src/til_settings.c
+++ b/src/til_settings.c
@@ -441,6 +441,36 @@ til_setting_desc_t * til_setting_desc_free(const til_setting_desc_t *desc)
 }
 
 
+int til_setting_desc_print_path(const til_setting_desc_t *desc, FILE *out)
+{
+	int	r;
+
+	assert(desc);
+	assert(out);
+
+	r = til_settings_print_path(desc->container, out);
+	if (r < 0)
+		return r;
+
+	/* XXX: spec.as_label handling is done in til_settings_print_path() since it
+	 * must apply anywhere within a path, potentially in a recurring fashion.
+	 * So all we're dealing with here is tacking a potentially named desc onto the end,
+	 * treating named descs as a sort of leaf of the path.  Though the desc may actually
+	 * describe a setting w/nested settings, i.e. it doesn't actually have to be a leaf
+	 * for this to be correct.  When its a parent of nested settings scenario, its key
+	 * would have been used to label the nested settings, but this print won't traverse
+	 * down from desc->container, only up the parents.
+	 */
+	if (desc->spec.key) {
+		r = fprintf(out, "/%s", desc->spec.key);
+		if (r < 0)
+			return r;
+	}
+
+	return 0;
+}
+
+
 /* TODO: spec checking in general needs refinement and to be less intolerant of
  * creative experimentation.
  */
@@ -579,3 +609,43 @@ int til_settings_label_setting(const til_settings_t *settings, const til_setting
 
 	return -ENOENT;
 }
+
+
+int til_settings_print_path(const til_settings_t *settings, FILE *out)
+{
+	const til_settings_t	*p, *parents[64];
+	size_t			i, n_parents;
+
+	assert(settings);
+	assert(out);
+
+	for (p = settings, n_parents = 0; p != NULL; p = p->parent)
+		n_parents++;
+
+	/* XXX: if this limitation becomes a problem we can always malloc()
+	 * space, but I can't imagine such deep settings heirarchies being real.
+	 */
+	assert(n_parents <= nelems(parents));
+
+	for (i = 0, p = settings; i < n_parents; p = p->parent, i++)
+		parents[n_parents - i - 1] = p;
+
+	for (i = 0; i < n_parents; i++) {
+		int	r;
+
+		r = fprintf(out, "/%s", parents[i]->label);
+		if (r < 0)
+			return r;
+
+		if (parents[i]->num > 0 &&
+		    parents[i]->entries[0]->desc &&
+		    parents[i]->entries[0]->desc->spec.as_label) {
+
+			r = fprintf(out, "/%s", parents[i]->entries[0]->value);
+			if (r < 0)
+				return r;
+		}
+	}
+
+	return 0;
+}
diff --git a/src/til_settings.h b/src/til_settings.h
index 2e2afe9..858ff66 100644
--- a/src/til_settings.h
+++ b/src/til_settings.h
@@ -56,8 +56,10 @@ int til_settings_apply_desc_generators(const til_settings_t *settings, const til
 
 int til_setting_desc_new(const til_settings_t *settings, const til_setting_spec_t *spec, const til_setting_desc_t **res_desc);
 til_setting_desc_t * til_setting_desc_free(const til_setting_desc_t *desc);
+int til_setting_desc_print_path(const til_setting_desc_t *desc, FILE *out);
 int til_setting_spec_check(const til_setting_spec_t *spec, const char *value);
 int til_settings_label_setting(const til_settings_t *settings, const til_setting_t *setting, char **res_label);
+int til_settings_print_path(const til_settings_t *settings, FILE *out);
 
 #ifndef TIL_SETTINGS_STR
 #define _TIL_SETTINGS_STR(s)	#s