add screensaver and optimize performance

Signed-off-by: Peter Siegmund <developer@mars3142.org>

components/ruth/include/persistence.h

@@ -1,8 +1,18 @@
 #pragma once
 
+typedef enum
+{
+    VALUE_TYPE_STRING,
+    VALUE_TYPE_INT32,
+} persistence_value_t;
+
 typedef struct
 {
-    char *name;
-
+    void *handle;
     void (*save)(const char *key, const char *value);
-} persistence_t;
+} persistence_t;
+
+void *persistence_init(const char *namespace_name);
+void persistence_save(persistence_value_t value_type, const char *key, const void *value);
+void *persistence_load(persistence_value_t value_type, const char *key, void *out);
+void persistence_deinit();