Wrapping C++ Classes in a PHP Extension - c++

Question

I m following the tutorial for wrapping c++ classes in a php extension.
I m using wamp server and php 5.4.16.
something going wrong in PHP_METHOD(Car, __construct).
It seems that after calling to
car_object *obj = ( car_object *) zend_object_store_get_object ( object TSRMLS_CC );
then obj ->car is not a valid address. when comment the line obj ->car = car, wamp is not shutting down. so i guess obj ->car is not valid or legal address.
bellow is my code:
vehicles.cc:
#include "php.h"
#include "car.h"
#define PHP_VEHICLES_EXTNAME "vehicles"
#define PHP_VEHICLES_EXTVER "0.1"
zend_object_handlers car_object_handlers;
struct car_object {
zend_object std;
Car *car;
};
zend_class_entry *car_ce;
void car_free_storage(void *object TSRMLS_DC)
{
car_object *obj = (car_object *)object;
delete obj->car;
zend_hash_destroy(obj->std.properties);
FREE_HASHTABLE(obj->std.properties);
delete obj->car;
efree(obj);
}
zend_object_value car_create_handler(zend_class_entry *type TSRMLS_DC)
{
zend_object_value retval;
car_object *obj = (car_object *)emalloc(sizeof(car_object));
memset(obj, 0, sizeof(car_object));
obj->std.ce = type;
ALLOC_HASHTABLE(obj->std.properties);
zend_hash_init(obj->std.properties, 0, NULL, ZVAL_PTR_DTOR, 0);
#if PHP_VERSION_ID < 50399
zval *tmp;
zend_hash_copy(obj->std.properties, &type->default_properties, (copy_ctor_func_t) zval_add_ref, (void *)&tmp, sizeof(zval *));
#else
object_properties_init(&(obj->std), type);
#endif
retval.handle = zend_objects_store_put(obj, NULL, car_free_storage, NULL TSRMLS_CC);
retval.handlers = &car_object_handlers;
return retval;
}
PHP_METHOD(Car, __construct)
{
long maxGear;
Car *car = NULL;
zval *object = getThis();
if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "l", &maxGear) == FAILURE) {
RETURN_NULL();
}
car = new Car(maxGear);
car_object *obj = ( car_object *) zend_object_store_get_object(object TSRMLS_CC );
//obj->car = car;
}
...
...
zend_function_entry car_methods[] = {
PHP_ME(Car, __construct, NULL, ZEND_ACC_PUBLIC | ZEND_ACC_CTOR)
PHP_ME(Car, shift, NULL, ZEND_ACC_PUBLIC)
PHP_ME(Car, accelerate, NULL, ZEND_ACC_PUBLIC)
PHP_ME(Car, brake, NULL, ZEND_ACC_PUBLIC)
PHP_ME(Car, getCurrentSpeed, NULL, ZEND_ACC_PUBLIC)
PHP_ME(Car, getCurrentGear, NULL, ZEND_ACC_PUBLIC)
{NULL, NULL, NULL}
};
PHP_MINIT_FUNCTION(vehicles)
{
zend_class_entry ce;
INIT_CLASS_ENTRY(ce, "Car", car_methods);
car_ce = zend_register_internal_class(&ce TSRMLS_CC);
car_ce->create_object = car_create_handler;
memcpy(&car_object_handlers, zend_get_std_object_handlers(), sizeof(zend_object_handlers));
car_object_handlers.clone_obj = NULL;
return SUCCESS;
}
zend_module_entry vehicles_module_entry = {
#if ZEND_MODULE_API_NO >= 20010901
STANDARD_MODULE_HEADER,
#endif
PHP_VEHICLES_EXTNAME,
NULL, /* Functions */
PHP_MINIT(vehicles),
NULL, /* MSHUTDOWN */
NULL, /* RINIT */
NULL, /* RSHUTDOWN */
NULL, /* MINFO */
#if ZEND_MODULE_API_NO >= 20010901
PHP_VEHICLES_EXTVER,
#endif
STANDARD_MODULE_PROPERTIES
};
ZEND_GET_MODULE ( vehicles );
car.h car.cc are the same as in the tutorial.
I guess that I'm missing something. maybe the call for "object_properties_init(&(obj->std), type);" in function car_create_handler is not correct..
thanks for your help/.

Answer 1

It seems that in your function car_free_storage, you are calling delete obj->car twice. This might not be a good idea.
Furthermore, when I was recently looking around another php module, I discovered that obj->std.properties is not always set to a valid address. So it might be worth checking if it isn't 0 before passing it to zend_hash_destroy. My code for this was:
if(obj->std.properties){
zend_hash_destroy(obj->std.properties);
FREE_HASHTABLE(obj->std.properties);
}