Support for arbitrary number of destroy callbacks.

src/cconfigspace.c

@@ -33,8 +33,14 @@ ccs_release_object(ccs_object_t object) {
 		return -CCS_INVALID_OBJECT;
 	obj->refcount -= 1;
 	if (obj->refcount == 0) {
-		if (obj->cb)
-			obj->cb(object, obj->cb_user_data);
+		if (obj->callbacks) {
+			_ccs_object_callback_t *cb = NULL;
+			while ( (cb = (_ccs_object_callback_t *)
+			              utarray_next(obj->callbacks, cb)) ) {
+				cb->callback(object, cb->user_data);
+			}
+			utarray_free(obj->callbacks);
+		}
 		ccs_result_t err = obj->ops->del(object);
 		if (err)
 			return err;
@@ -65,6 +71,13 @@ ccs_object_get_refcount(ccs_object_t  object,
 	return CCS_SUCCESS;
 }
 
+static const UT_icd _object_callback_icd = {
+	sizeof(_ccs_object_callback_t),
+	NULL,
+	NULL,
+	NULL
+};
+
 ccs_result_t
 ccs_object_set_destroy_callback(ccs_object_t  object,
                                 void (*callback)(
@@ -74,8 +87,13 @@ ccs_object_set_destroy_callback(ccs_object_t  object,
 	_ccs_object_internal_t *obj = (_ccs_object_internal_t *)object;
 	if (!obj)
 		return -CCS_INVALID_OBJECT;
-	obj->cb = callback;
-	obj->cb_user_data = user_data;
+	if (!callback)
+		return -CCS_INVALID_VALUE;
+	if (!obj->callbacks)
+		utarray_new(obj->callbacks, &_object_callback_icd);
+
+	_ccs_object_callback_t cb = { callback, user_data };
+	utarray_push_back(obj->callbacks, &cb);
 	return CCS_SUCCESS;
 }
 

src/cconfigspace_internal.h

@@ -2,6 +2,7 @@
 #define _CONFIGSPACE_INTERNAL_H
 
 #include <cconfigspace.h>
+#include "utarray.h"
 
 static inline ccs_bool_t
 _ccs_interval_include(ccs_interval_t *interval, ccs_numeric_t value) {
@@ -45,11 +46,16 @@ struct _ccs_object_ops_s {
 
 typedef struct _ccs_object_ops_s _ccs_object_ops_t;
 
+struct _ccs_object_callback_s {
+	ccs_object_release_callback_t  callback;
+	void                          *user_data;
+};
+typedef struct _ccs_object_callback_s _ccs_object_callback_t;
+
 struct _ccs_object_internal_s {
 	ccs_object_type_t              type;
 	int32_t                        refcount;
-        ccs_object_release_callback_t  cb;
-	void                          *cb_user_data;
+	UT_array                      *callbacks;
 	_ccs_object_ops_t             *ops;
 };
 
@@ -67,8 +73,7 @@ _ccs_object_init(_ccs_object_internal_t *o,
                  _ccs_object_ops_t      *ops) {
 	o->type = t;
 	o->refcount = 1;
-	o->cb = NULL;
-	o->cb_user_data = NULL;
+	o->callbacks = NULL;
 	o->ops = ops;
 }
 

src/expression.c

@@ -1317,7 +1317,7 @@ ccs_variable_get_hyperparameter(ccs_expression_t      expression,
 }
 
 static ccs_result_t _get_hyperparameters(ccs_expression_t  expression,
-                                        UT_array         *array) {
+                                         UT_array         *array) {
 	CCS_CHECK_OBJ(expression, CCS_EXPRESSION);
 	ccs_result_t err;
 	if (expression->data->type == CCS_VARIABLE) {