Destructor callback for reference #38
Description
Background
cfl_variant_destroy destroys if a variant is string, bytes, array or kvlist.
It doesn't if the type is reference.
cfl_array and cfl_kvlist supports reference.
It means that user needs to release before destroying them.
e.g.
for (index = 0 ; index < array->entry_count ; index++) {
if(array->entries[index] != NULL && array->entries[index].type == CFL_VARIANT_REFERENCE) {
free(array->entries[index].data.as_reference);
}
}
cfl_array_destroy(array);We need to save keys to fetch references.
for (index = 0 ; index < keys_size ; index++) {
var = cfl_kvlist_fetch(kvlist, keys[index]);
if (var != NULL && var.type == CFL_VARIANT_REFERENCE ) {
free(var.data.as_reference)
}
}
cfl_kvlist_destroy(kvlist);I think it is messy.
Proposal
I propose to add a function pointer to struct cfl_variant and add a new function cfl_variant_set_destructor(funcptr).
cfl_variant_destroy calls funcptr if it is not NULL.
It allows user to register destructor callback.
cfl_kvlist_insert_reference and cfl_array_append_reference will be extracted to pass funcptr.
Note: Do not set callback on creating
We can extract like cfl_variant_create_from_reference(value, funcptr).
However it causes issue following case.
The reference will be released when cfl_array_append is failed.
int cfl_array_append_reference(struct cfl_array *array, void *value, void (*funcptr) (void *))
{
struct cfl_variant *value_instance;
int result;
value_instance = cfl_variant_create_from_reference(value, funcptr); // set callback on create
if (value_instance == NULL) {
return -1;
}
result = cfl_array_append(array, value_instance);
if (result) {
cfl_variant_destroy(value_instance); // reference is released !
return -2;
}
return 0;
}