Edit report at http://bugs.php.net/bug.php?id=52318&edit=1
ID: 52318
Comment by: brendel at krumedia dot de
Reported by: brendel at krumedia dot de
Summary: Weak references for PHP
Status: Open
Type: Feature/Change Request
Package: Scripting Engine problem
PHP Version: Irrelevant
Block user comment: N
New Comment:
bastard dot internets at gmail dot com,
for framework developers this would be very useful. It just means, when
the user of the framework no longer use a certain object the framework
also should not longer waste memory. There are no pitfalls for the user.
But the framework is more flexible.
Previous Comments:
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[2010-08-09 08:57:46] bastard dot internets at gmail dot com
brendel at krumedia dot de - Good call: "$user now contains a new user
object"
When looking at it from a security perspective, I do believe you just
killed all my arguments against. Not because you've proven it
impossible, but because unless the developer explicitly wants that
functionality, their code will have a thousand holes.
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[2010-08-09 08:21:48] brendel at krumedia dot de
Hi bastard dot internets at gmail dot com,
see how variable references are no solution:
<?php
$repository = new SplWeakArrayValues();
$user = $dbTable->getUserById(1);
$repository[$user->id] = $user;
// Now two variables hold object references to one user object
$user = new User();
// $user now contains a new user object and the old one should have
// been removed from the repository. This time i do not assign null
// but another (transient) user object.
// count($repository) should equal 0.
?>
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[2010-08-09 08:08:26] bastard dot internets at gmail dot com
brendel at krumedia dot de - You got me at "Also count($repository)
should equal 0"
As I said earlier, "Registry::$Collection[$a->id] = null;" will set all
variables referring to this object handle to null globally. However,
count(Registry::$Collection) is still 1.
I'd still argue this is possible using existing language features.
However, it means juggling so many references, forced implementing
spaghetti code to get a solution, and a single missing "&" symbol
anywhere leading to hours of debugging. And, I just found myself
needing just such a solution.
So, I'd have to vote for a built-in interface or class like you
describe.
------------------------------------------------------------------------
[2010-08-03 16:43:39] brendel at krumedia dot de
Sample code use case:
<?php
$repository = new SplWeakArrayValues(); // assume it implements
// ArrayAccess and others
$user = $this->userObjectFromSomewhere();
$repository[$user->id] = $user;
// Now two variables hold object references to one user object
$user = null;
// Since $repository is weak, the destructor of the class of $user
should have been called now
// Also count($repository) should equal 0
?>
------------------------------------------------------------------------
[2010-08-03 16:32:36] brendel at krumedia dot de
bastard dot internets at gmail dot com, please see the constructor
parameter "weakKeys" of
http://livedocs.adobe.com/flex/3/langref/flash/utils/Dictionary.html
to
get an idea. This is not about variable references.
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