PLUGINS: mechanism for cleaning up resources when out of scope

Author: chrisws

src/common/hashmap.c

@@ -128,6 +128,7 @@ void hashmap_create(var_p_t map, int size) {
   map->v.m.id = -1;
   map->v.m.lib_id = -1;
   map->v.m.cls_id = -1;
+  map->v.m.ref = -1;
   if (size == 0) {
     map->v.m.size = MAP_SIZE;
   } else {

src/common/plugins.c

@@ -39,7 +39,7 @@ typedef int (*sblib_exec_fn)(int, int, slib_par_t *, var_t *);
 typedef int (*sblib_getname_fn) (int, char *);
 typedef int (*sblib_count_fn) (void);
 typedef int (*sblib_init_fn) (const char *);
-typedef int (*sblib_free_fn)(int, int);
+typedef int (*sblib_free_fn) (int, int);
 typedef void (*sblib_close_fn) (void);
 
 typedef struct {
@@ -476,6 +476,7 @@ static int slib_exec(slib_t *lib, var_t *ret, int index, int proc) {
 
   if (success && v_is_type(ret, V_MAP)) {
     ret->v.m.lib_id = lib->_id;
+    ret->v.m.ref = 1;
   }
 
   return success;

src/common/var.c

@@ -567,6 +567,7 @@ void v_move(var_t *dest, const var_t *src) {
     dest->v.m.id = src->v.m.id;
     dest->v.m.lib_id = src->v.m.lib_id;
     dest->v.m.cls_id = src->v.m.cls_id;
+    dest->v.m.ref = src->v.m.ref;
     break;
   case V_REF:
     dest->v.ref = src->v.ref;

src/common/var_map.c

@@ -171,7 +171,10 @@ var_p_t map_elem_key(const var_p_t var_p, int index) {
  */
 void map_free(var_p_t var_p) {
   if (var_p->type == V_MAP) {
-    if (var_p->v.m.lib_id != -1 && var_p->v.m.cls_id != -1 && var_p->v.m.id != -1) {
+    if (var_p->v.m.lib_id != -1 &&
+        var_p->v.m.cls_id != -1 &&
+        var_p->v.m.id != -1 &&
+        --var_p->v.m.ref == 0) {
       plugin_free(var_p->v.m.lib_id, var_p->v.m.cls_id, var_p->v.m.id);
     }
     hashmap_destroy(var_p);
@@ -297,6 +300,7 @@ void map_set(var_p_t dest, const var_p_t src) {
     dest->v.m.id = src->v.m.id;
     dest->v.m.lib_id = src->v.m.lib_id;
     dest->v.m.cls_id = src->v.m.cls_id;
+    dest->v.m.ref = src->v.m.ref + 1;
   }
 }
 

src/include/var.h

@@ -69,11 +69,13 @@ typedef struct var_s {
     struct {
       // pointer the map structure
       void *map;
+
       uint32_t count;
       uint32_t size;
       uint32_t id;
       uint32_t lib_id;
       uint32_t cls_id;
+      uint32_t ref;
     } m;
 
     // reference variable