til_setup: add helper for setup_func baking fails

This introduces til_setup_free_with_failed_setting_ret_err()
which just does the common idiom of:

- free the setup
- store the failed setting
- return with err code

so all these failure cases can be reduced to just a direct return
of calling this function.

2 files changed, 16 insertions, 0 deletions

diff --git a/src/til_setup.c b/src/til_setup.c
index ce95366..c06614f 100644
--- a/src/til_setup.c
+++ b/src/til_setup.c
@@ -110,3 +110,17 @@ void * til_setup_free(til_setup_t *setup)
 
 	return NULL;
 }
+
+
+/* ergonomic helper for setup_funcs to use in res_setup baking */
+int til_setup_free_with_failed_setting_ret_err(til_setup_t *setup, til_setting_t *failed_setting, til_setting_t **res_setting, int err)
+{
+	assert(failed_setting);
+	assert(res_setting);
+	assert(err < 0);
+
+	til_setup_free(setup);
+	*res_setting = failed_setting;
+
+	return err;
+}
diff --git a/src/til_setup.h b/src/til_setup.h
index 905dd6e..eac1444 100644
--- a/src/til_setup.h
+++ b/src/til_setup.h
@@ -4,6 +4,7 @@
 #include <stdint.h>
 
 typedef struct til_settings_t til_settings_t;
+typedef struct til_setting_t til_setting_t;
 typedef struct til_setup_t til_setup_t;
 
 struct til_setup_t {
@@ -17,5 +18,6 @@ struct til_setup_t {
 void * til_setup_new(const til_settings_t *settings, size_t size, void (*free_func)(til_setup_t *setup), const void *creator);
 void * til_setup_ref(til_setup_t *setup);
 void * til_setup_free(til_setup_t *setup);
+int til_setup_free_with_failed_setting_ret_err(til_setup_t *setup, til_setting_t *failed_setting, til_setting_t **res_setting, int err);
 
 #endif