SplObjectStorage::detach()

(PHP 5 >= 5.1.0, PHP 7)

Removes an object from the storage

说明

publicSplObjectStorage::detach(object $object) : void

Removes the object from the storage.

参数

$object

The object to remove.

返回值

没有返回值。

范例

SplObjectStorage::detach() example

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

以上例程的输出类似于：

int(1)
int(0)

参见

• SplObjectStorage::attach() Adds an object in the storage
• SplObjectStorage::removeAll() Removes objects contained in another storage from the current storage

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.

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

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));
?>