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SplObjectStorage::detach

(PHP 5 >= 5.1.0, PHP 7, PHP 8)

SplObjectStorage::detachRemoves an object from the storage

Beschreibung

public SplObjectStorage::detach(object $object): void

Removes the object from the storage.

Parameter-Liste

object

The object to remove.

Rückgabewerte

Es wird kein Wert zurückgegeben.

Beispiele

Beispiel #1 SplObjectStorage::detach() example

<?php
$o
= new stdClass;
$s = new SplObjectStorage();
$s->attach($o);
var_dump(count($s));
$s->detach($o);
var_dump(count($s));
?>

Das oben gezeigte Beispiel erzeugt eine ähnliche Ausgabe wie:

int(1)
int(0)

Siehe auch

add a note

User Contributed Notes 4 notes

up
12
r dot wilczek at web-appz dot de
13 years ago
Detaching the current entry from the storage prevents SplObjectStorage::next() to operate.

Example as a PHPUnit-test:

<?php
public function testDetachingCurrentPreventsNext()
{
$storage = new SplObjectStorage;
$storage->attach(new stdClass);
$storage->attach(new stdClass);
$storage->rewind();
$iterated = 0;
$expected = $storage->count();
while (
$storage->valid()) {
$iterated++;
$storage->detach($storage->current());
$storage->next();
}
$this->assertEquals($expected, $iterated);
}
?>

This test will fail, for the iteration will never reach the second stdClass.
SplObjectStorage::next() obviously relies on the current element to be valid.

If you want to detach objects during iterations, you should dereference objects, before you call next() and detach the reference after next():

<?php
public function testDetachingReferenceAfterNext()
{
$storage = new SplObjectStorage;
$storage->attach(new stdClass);
$storage->attach(new stdClass);
$storage->rewind();
$iterated = 0;
$expected = $storage->count();
while (
$storage->valid()) {
$iterated++;
$object = $storage->current();
$storage->next();
$storage->detach($object);
}
$this->assertEquals($expected, $iterated);
}
?>

This test will pass.
up
3
alan dot bem at gmail dot com
10 years ago
SplObjectSotage::detach() has a bug - it rewinds internal array pointer.
Remember that - when looping over the storage - as it has no workaround.

https://bugs.php.net/bug.php?id=65629&edit=2
up
1
nawa
1 year ago
There was problematic case when detaching object inside loop, because SplObjectStorage need to call next() before detach()

Example using foreach :
<?php
/**
* spl object storage bugs when looping
* @see https://bugs.php.net/bug.php?id=65629
*/
$firstStorage = new SplObjectStorage();
$secondStorage = new SplObjectStorage();
// temporary storage
$temporaryStorage = new SplObjectStorage();
// range 0 - 9
$range = range(0, 9);

foreach (
$range as $id) {
$object = new stdClass();
$object->id = $id;
$firstStorage->attach($object);
$secondStorage->attach($object);
}

// direct detach inside loop
foreach ($firstStorage as $storage) {
// on common array it will detach all even in loop
// but object storage still remain 1 object
if ($storage->id < 5) {
$firstStorage->detach($storage);
}
}

// collect storage into temporary splObjectStorage
foreach ($secondStorage as $storage) {
// collect into temporary storage
if ($storage->id < 5) {
$temporaryStorage->attach($storage);
}
}
// removeAll by temporary Storage
$secondStorage->removeAll($temporaryStorage);

var_dump(count($firstStorage)); // int(6)
var_dump(count($secondStorage)); // int(5)
?>

Example using while :
<?php
$firstStorage
= new SplObjectStorage();
$secondStorage = new SplObjectStorage();
// temporary storage
$temporaryStorage = new SplObjectStorage();
// range 0 - 9
$range = range(0, 9);

foreach (
$range as $id) {
$object = new stdClass();
$object->id = $id;
$firstStorage->attach($object);
$secondStorage->attach($object);
}

$firstStorage->rewind();
while (
$firstStorage->valid() && ($current = $firstStorage->current())) {
if (
$current->id < 5) {
$firstStorage->detach($current);
}
// don't call next after detach
$firstStorage->next();
}

$secondStorage->rewind();
while (
$secondStorage->valid() && ($current = $secondStorage->current())) {
// call next behavior before detach
$secondStorage->next();
if (
$current->id < 5) {
$secondStorage->detach($current);
}
}

var_dump(count($firstStorage)); // int(6)
var_dump(count($secondStorage)); // int(5)
?>
up
1
Hayley Watson
6 years ago
No complaints from SplObjectStorage if you try to detach an object that isn't in the collection; it's a no-op.

<?php

$o
= new StdClass;
$t = new StdClass;
$s = new SplObjectStorage();
$s->attach($o);
var_dump(count($s));
$s->detach($t); // Didn't attach this one.
var_dump(count($s));

?>
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