On 07.09.2016 at 20:11, Fleshgrinder wrote:
> On 9/7/2016 8:57 AM, Michał Brzuchalski wrote:
>
>> AFAIK CoW in case of objects would be impossible to implement.
>
> Nothing is impossible. :)
>
> We have full access to the real object inside of zend_std_write_property
> and can easily clone it, perform the desired changes and return without
> affecting anyone.
>
> I am not 100% sure how to do this without fiddling around a bit.
>
> @nikic and @afaults: I am really sorry to bother you both but you guys
> simply know the PHP source endlessly good. What do you think, would it
> be possible to implement copy-on-write for an object as we have it with
> our scalar and compound types?
>
> final class A {
> public $p;
> }
>
> $a = new A;
> $b = $a;
>
> var_dump($a === $b); // bool(true)
>
> $b->p = 1;
>
> var_dump($a === $b); // bool(false)
>
> It's only about writing to existing properties.
Ah, good old PHP 4, see <https://3v4l.org/VaD1W#v5328>. :-)
--
Christoph M. Becker
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