PLUGINS: mechanism for cleaning up resources when out of scope

Author: chrisws

src/common/hashmap.c

@@ -126,6 +126,8 @@ void hashmap_create(var_p_t map, int size) {
   map->type = V_MAP;
   map->v.m.count = 0;
   map->v.m.id = -1;
+  map->v.m.lib_id = -1;
+  map->v.m.cls_id = -1;
   if (size == 0) {
     map->v.m.size = MAP_SIZE;
   } else {

src/common/plugins.c

@@ -39,6 +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 void (*sblib_close_fn) (void);
 
 typedef struct {
@@ -47,6 +48,7 @@ typedef struct {
   void *_handle;
   sblib_exec_fn _sblib_proc_exec;
   sblib_exec_fn _sblib_func_exec;
+  sblib_free_fn _sblib_free;
   ext_func_node_t *_func_list;
   ext_proc_node_t *_proc_list;
   uint32_t _id;
@@ -304,6 +306,7 @@ static void slib_import_routines(slib_t *lib, int comp) {
 
   lib->_sblib_func_exec = slib_getoptptr(lib, "sblib_func_exec");
   lib->_sblib_proc_exec = slib_getoptptr(lib, "sblib_proc_exec");
+  lib->_sblib_free = slib_getoptptr(lib, "sblib_free");
   sblib_count_fn fcount = slib_getoptptr(lib, "sblib_proc_count");
   sblib_getname_fn fgetname = slib_getoptptr(lib, "sblib_proc_getname");
 
@@ -471,6 +474,10 @@ static int slib_exec(slib_t *lib, var_t *ret, int index, int proc) {
     free(ptable);
   }
 
+  if (success && v_is_type(ret, V_MAP)) {
+    ret->v.m.lib_id = lib->_id;
+  }
+
   return success;
 }
 
@@ -598,6 +605,13 @@ int plugin_funcexec(int lib_id, int index, var_t *ret) {
   return result;
 }
 
+void plugin_free(int lib_id, int cls_id, int id) {
+  slib_t *lib = get_lib(lib_id);
+  if (lib && lib->_sblib_free) {
+    lib->_sblib_free(cls_id, id);
+  }
+}
+
 void plugin_close() {
   for (int i = 0; i < MAX_SLIBS; i++) {
     if (plugins[i]) {
@@ -626,5 +640,6 @@ int plugin_get_kid(int lib_id, const char *keyword) { return -1; }
 void *plugin_get_func(const char *name) { return 0; }
 int plugin_procexec(int lib_id, int index) { return -1; }
 int plugin_funcexec(int lib_id, int index, var_t *ret) { return -1; }
+void plugin_free(int lib_id, int cls_id, int id) {}
 void plugin_close() {}
 #endif

src/common/plugins.h

@@ -55,6 +55,11 @@ int plugin_procexec(int lib_id, int index);
 //
 int plugin_funcexec(int lib_id, int index, var_t *ret);
 
+//
+// cleanup any resources held against the map data
+//
+void plugin_free(int lib_id, int cls_id, int id);
+
 //
 // closes the plugin system
 //

src/common/var.c

@@ -565,6 +565,8 @@ void v_move(var_t *dest, const var_t *src) {
     dest->v.m.count = src->v.m.count;
     dest->v.m.size = src->v.m.size;
     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;
     break;
   case V_REF:
     dest->v.ref = src->v.ref;

src/common/var_map.c

@@ -11,6 +11,7 @@
 #include "common/sys.h"
 #include "common/pproc.h"
 #include "common/hashmap.h"
+#include "common/plugins.h"
 #include "include/var_map.h"
 
 #define BUFFER_GROW_SIZE 64
@@ -170,6 +171,9 @@ 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) {
+      plugin_free(var_p->v.m.lib_id, var_p->v.m.cls_id, var_p->v.m.id);
+    }
     hashmap_destroy(var_p);
     v_init(var_p);
   }
@@ -291,6 +295,8 @@ void map_set(var_p_t dest, const var_p_t src) {
     hashmap_foreach(src, map_set_cb, &cb);
     dest->v.m.count = src->v.m.count;
     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;
   }
 }
 

src/include/module.h

@@ -116,6 +116,16 @@ int sblib_func_getname(int index, char *func_name);
  */
 int sblib_func_exec(int index, int param_count, slib_par_t *params, var_t *retval);
 
+/**
+ * @ingroup modlib
+ *
+ * executes a function
+ *
+ * @param cls_id the variable class identifier
+ * @param id the variable instance identifier
+ */
+void sblib_free(int cls_id, int id);
+
 /**
  * @ingroup modlib
  *

src/include/var.h

@@ -72,6 +72,8 @@ typedef struct var_s {
       uint32_t count;
       uint32_t size;
       uint32_t id;
+      uint32_t lib_id;
+      uint32_t cls_id;
     } m;
 
     // reference variable