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Thread-Topic: [PHP-DEV] Exposing object handles to userland
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Date: Wed, 5 Jul 2017 00:01:26 +0000
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Subject: RE: [PHP-DEV] Exposing object handles to userland
From: tysonandre775@hotmail.com (tyson andre)

There was a proposal back in 2015 to implement
a function spl_object_id(object $o) : int`,
which directly returns the object handle
(similar to `spl_object_hash`, but as an integer, not a string).
I'm interested in finishing implementing spl_object_id for php 7.2=20

I already have working code implementing spl_object_id() at
https://github.com/TysonAndre/php-src/pull/1
The implementation XORs the object handle with the=20
exact same random bits that `spl_object_hash` would.

Previous emails from 2015 can be seen here:
- https://marc.info/?t=3D143835274500003&r=3D1&w=3D2

Previous comment by a PHP maintainer in support of `spl_object_id()`
- https://marc.info/?l=3Dphp-internals&m=3D143837339210596&w=3D2

I'm unsure if an RFC is necessary. I have two pending questions.

- Can two objects can have the same object id
  but different object handlers?
  (e.g. iterators of some built in classes?)
  I'm not familiar enough with PHP's history to be sure.
- Can the the largest object handle be larger
  than the size of `zend_long` in 32-bit systems?

Example places where this would be useful:

1. https://marc.info/?l=3Dphp-internals&m=3D143849841618494&w=3D2

2. I also recently wanted to track a large number of (cloneable)
   small sets of objects in an application that sometimes used a lot of mem=
ory,
   and the fact that arrays support copy on write helped save memory
   relative to SplObjectHash if arrays and integer keys were used.
   See https://github.com/etsy/phan/pull/729#issuecomment-299289378

- Tyson Andre (tandre)=