settings: add setting_desc_t.random() method

To facilitate random setting of these flexible string-oriented
settings, support a random helper supplied with the description.

This helper would return a valid random string to be used with the
respective setting being described.

Immediate use case is the rtv module, which also gets fixed up to
use it in this commit.

3 files changed, 10 insertions, 1 deletions

diff --git a/src/modules/rtv/rtv.c b/src/modules/rtv/rtv.c
index a9d0399..c4c6dd2 100644
--- a/src/modules/rtv/rtv.c
+++ b/src/modules/rtv/rtv.c
@@ -73,7 +73,13 @@ static char * randomize_module_setup(const rototiller_module_t *module)
 		return NULL;
 
 	while (module->setup(settings, &desc) > 0) {
-		if (desc->values) {
+		if (desc->random) {
+			char	*value;
+
+			value = desc->random();
+			settings_add_value(settings, desc->key, value);
+			free(value);
+		} else if (desc->values) {
 			int	n;
 
 			for (n = 0; desc->values[n]; n++);
diff --git a/src/settings.c b/src/settings.c
index e5560b0..02c8e8d 100644
--- a/src/settings.c
+++ b/src/settings.c
@@ -265,6 +265,8 @@ int setting_desc_clone(const setting_desc_t *desc, setting_desc_t **res_desc)
 		}
 	}
 
+	d->random = desc->random;
+
 	/* TODO: handle allocation errors above... */
 	*res_desc = d;
 
diff --git a/src/settings.h b/src/settings.h
index 198f8b6..af47326 100644
--- a/src/settings.h
+++ b/src/settings.h
@@ -11,6 +11,7 @@ typedef struct setting_desc_t {
 	const char	*preferred;	/* if there's a default, this is it */
 	const char	**values;	/* if a set of values is provided, listed here */
 	const char	**annotations;	/* if a set of values is provided, annotations for those values may be listed here */
+	char *		(*random)(void);/* if set, returns a valid random value for this setting */
 } setting_desc_t;
 
 /* For conveniently representing setting description generators */