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Date: Mon, 2 Feb 2015 15:18:46 +0800
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To: francois@tekwire.net
Cc: PHP Internals <internals@lists.php.net>, Dmitry Stogov <dmitry@zend.com>
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Subject: Re: [PHP-DEV] [DICUSS]Cleanup resource handling APIs
From: laruence@php.net (Xinchen Hui)

Hey:


On Mon, Feb 2, 2015 at 3:11 PM, Xinchen Hui <laruence@php.net> wrote:
> Hey:
>
> On Mon, Feb 2, 2015 at 2:51 PM, Fran=C3=A7ois Laupretre <francois@tekwire=
.net> wrote:
>>> De : Xinchen Hui [mailto:laruence@php.net]
>>>      we used to use lval of zval as a handle to access resource type..
>>>
>>>      but now, we introduced a new type IS_RESOURCE, which make the
>>> handle(id) sort of redundant .
>>
>> Wrong. The IS_RESOURCE type has nothing to do with PHP 7. Only zend_reso=
urce is new. And handle is not redundant.
> of course it's a typo. I meant zend_resource
>>
>>>      further more, the common usage when handling resource is like:
>>>
>>>       if (zend_parse_parameters(ZEND_NUM_ARGS(), "rl", &result,
>>> &offset) =3D=3D FAILURE) {
>>>         return;
>>>     }
>>>     ZEND_FETCH_RESOURCE(mysql_result, MYSQL_RES *, result, -1, "MySQL
>>> result", le_result);
>>>
>>>     as you can see, we use "r" to receive a IS_RESOURCE type, that
>>> means, check the type in ZEND_FETCH_RESOURCE is overhead..
>>
>> There's no overhead here. Zend_parse_parameters checks that received arg=
 is IS_RESOURCE. Fetch then checks that received resource is one of the acc=
epted resource types. Sorry to say that, but are you sure you understand th=
e difference between zval types and resource types ?
> ..... do you really read the FETCH_RESOURCE?
>
> ZEND_API void *zend_fetch_resource(zval *passed_id, int default_id,
> const char *resource_type_name, int *found_resource_type, int
> num_resource_types, ...)
> {
>     int actual_resource_type;
> //  void *resource;
>     va_list resource_types;
>     int i;
>     zend_resource *res;
>     const char *space;
>     const char *class_name;
>
>     if (default_id=3D=3D-1) { /* use id */
>         if (!passed_id) {
>             if (resource_type_name) {
>                 class_name =3D get_active_class_name(&space);
>                 zend_error(E_WARNING, "%s%s%s(): no %s resource
> supplied", class_name, space, get_active_function_name(),
> resource_type_name);
>             }
>             return NULL;
>         } else if (Z_TYPE_P(passed_id) !=3D IS_RESOURCE) { // < =3D=3D=3D=
 what are this?
>             if (resource_type_name) {
>                 class_name =3D get_active_class_name(&space);
>                 zend_error(E_WARNING, "%s%s%s(): supplied argument is
> not a valid %s resource", class_name, space,
> get_active_function_name(), resource_type_name);
>             }
>             return NULL;
>         }
>
>
>>
>>>    ZEND_API void *zend_fetch_resource(zval *passed_id, int default_id,
>>> const char *resource_type_name, int *found_resource_type, int
>>> num_resource_types, ...)
>>>
>>>    we use va_args to passing resource type, that means, the rescue
>>> type arguments can not be passed by register but by stack.. which is a
>>> little low effiicient .
>>
>> What do you mean with 'rescue' type ?
> expected resource_type
>>
>> Fetch is supposed to check for a variable number of possible resource ty=
pes. It could probably be restricted to 2 possible types as, generally, it =
is the maximum (one for non-persistent, one for persistent). But I am not s=
ure the overhead of passing arg on the stack justifies a change. Remember t=
hat id is searched in an array, which takes probably much more time that pu=
shing/popping one or two arguments.
>>
>>>    so, I'd like propose a zend_resource handling API cleanup..
>>>
>>>    1.  DROP ZEND_REGISTER_RESOURCE/FETCH_RESOURCE.
>>>
>>>    2.  add :
>>>
>>>        ZEND_API void *zend_fetch_resource(zend_resource *res, const
>>> char *resource_type_name, int resource_type);
>>> ZEND_API void *zend_fetch_resource2(zend_resource *res, const char
>>> *resource_type_name, int *found_type, int resource_type, int
>>> resource_type2);
>>> ZEND_API void *zend_fetch_resource_ex(zval *res, const char
>>> *resource_type_name, int resource_type);
>>> ZEND_API void *zend_fetch_resource2_ex(zval *res, const char
>>> *resource_type_name, int *found_type, int resource_type, int
>>> resource_type2);
>>
>> If you drop ZEND_REGISTER_RESOURCE, how do you register new resources ? =
Or do you mean you don't register them any more ? But registering them is m=
andatory if we want them to be freed when request ends.
>>
>>> furthermore, I'd like to discuss remove the handle in zend_resource str=
uct..
>>>
>>> it may breaks some usage (use resource as long/double/string)
>>>
>>>   case IS_RESOURCE: {
>>>            char buf[sizeof("Resource id #") + MAX_LENGTH_OF_LONG];
>>>            int len;
>>>
>>>            len =3D snprintf(buf, sizeof(buf), "Resource id #"
>>>ZEND_LONG_FMT, (zend_long)Z_RES_HANDLE_P(op));
>>>            return zend_string_init(buf, len, 0);
>>>        }
>>
>> OK. You want to remove resource registration. But resources don't work t=
his way (see http://devzone.zend.com/446/extension-writing-part-iii-resourc=
es/). If you remove the handle, you remove the whole zend_list API.
>>
>> The zend_resource struct is not a structure you may fill with random dat=
a. Using the handle to store long/double/string is not a legitimate usage.
> ....I think you don't understand what I am talking about. sorry
I think I'd better to explain a bit more.

we used to use handle to lookup a resource in EG(regular_list).. and
store the "int handle" into lval of zval.

but now, we use zend_resource * , which can be directly accessed via
Z_RES_P(zval).

that's why I think the "handle" is a little redundant ..

is that clear?

thanks
>
>
> thanks
>>
>> Regards
>>
>> Fran=C3=A7ois
>>
>>
>>
>>
>
>
>
> --
> Xinchen Hui
> @Laruence
> http://www.laruence.com/



--=20
Xinchen Hui
@Laruence
http://www.laruence.com/