php7-mysql-data/Kapitel_10/Lektion_5/vendor/myclabs/deep-copy

DeepCopy

DeepCopy helps you create deep copies (clones) of your objects. It is designed to handle cycles in the association graph.

How?

Install with Composer:

composer require myclabs/deep-copy

Use simply:

use DeepCopy\DeepCopy;

$deepCopy = new DeepCopy();
$myCopy = $deepCopy->copy($myObject);

Why?

• How do you create copies of your objects?

$myCopy = clone $myObject;

• How do you create deep copies of your objects (i.e. copying also all the objects referenced in the properties)?

You use __clone() and implement the behavior yourself.

• But how do you handle cycles in the association graph?

Now you're in for a big mess :(

Using simply clone

Overridding __clone()

With DeepCopy

How it works

DeepCopy traverses recursively all your object's properties and clones them.

To avoid cloning the same object twice (and thus, keep you object graph), it keeps a hash-map of all instances.

Going further

You can add filters to customize the copy process.

The method to add a filter is $deepCopy->addFilter($filter, $matcher), with $filter implementing DeepCopy\Filter\Filter and $matcher implementing DeepCopy\Matcher\Matcher.

We provide some generic filters and matchers.

Matchers

• DeepCopy\Matcher applies on a object attribute.
• DeepCopy\TypeMatcher applies on any element found in graph, including array elements.

Property name

The PropertyNameMatcher will match a property by its name:

use DeepCopy\Matcher\PropertyNameMatcher;

$matcher = new PropertyNameMatcher('id');
// will apply a filter to any property of any objects named "id"

Specific property

The PropertyMatcher will match a specific property of a specific class:

use DeepCopy\Matcher\PropertyMatcher;

$matcher = new PropertyMatcher('MyClass', 'id');
// will apply a filter to the property "id" of any objects of the class "MyClass"

Type

The TypeMatcher will match any element by its type (instance of a class or any value that could be parameter of gettype() function):

use DeepCopy\TypeMatcher\TypeMatcher;

$matcher = new TypeMatcher('Doctrine\Common\Collections\Collection');
// will apply a filter to any object that is an instance of Doctrine\Common\Collections\Collection

Filters

• DeepCopy\Filter applies a transformation to the object attribute matched by DeepCopy\Matcher.
• DeepCopy\TypeFilter applies a transformation to any element matched by DeepCopy\TypeMatcher.

SetNullFilter

Let's say for example that you are copying a database record (or a Doctrine entity), so you want the copy not to have any ID:

use DeepCopy\DeepCopy;
use DeepCopy\Filter\SetNullFilter;
use DeepCopy\Matcher\PropertyNameMatcher;

$myObject = MyClass::load(123);
echo $myObject->id; // 123

$deepCopy = new DeepCopy();
$deepCopy->addFilter(new SetNullFilter(), new PropertyNameMatcher('id'));
$myCopy = $deepCopy->copy($myObject);

echo $myCopy->id; // null

KeepFilter

If you want a property to remain untouched (for example, an association to an object):

use DeepCopy\DeepCopy;
use DeepCopy\Filter\KeepFilter;
use DeepCopy\Matcher\PropertyMatcher;

$deepCopy = new DeepCopy();
$deepCopy->addFilter(new KeepFilter(), new PropertyMatcher('MyClass', 'category'));
$myCopy = $deepCopy->copy($myObject);

// $myCopy->category has not been touched

ReplaceFilter

1. If you want to replace the value of a property:

use DeepCopy\DeepCopy;
use DeepCopy\Filter\ReplaceFilter;
use DeepCopy\Matcher\PropertyMatcher;

$deepCopy = new DeepCopy();
$callback = function ($currentValue) {
    return $currentValue . ' (copy)'
};
$deepCopy->addFilter(new ReplaceFilter($callback), new PropertyMatcher('MyClass', 'title'));
$myCopy = $deepCopy->copy($myObject);

// $myCopy->title will contain the data returned by the callback, e.g. 'The title (copy)'

2. If you want to replace whole element:

use DeepCopy\DeepCopy;
use DeepCopy\TypeFilter\ReplaceFilter;
use DeepCopy\TypeMatcher\TypeMatcher;

$deepCopy = new DeepCopy();
$callback = function (MyClass $myClass) {
    return get_class($myClass);
};
$deepCopy->addTypeFilter(new ReplaceFilter($callback), new TypeMatcher('MyClass'));
$myCopy = $deepCopy->copy(array(new MyClass, 'some string', new MyClass));

// $myCopy will contain ['MyClass', 'some stirng', 'MyClass']

The $callback parameter of the ReplaceFilter constructor accepts any PHP callable.

ShallowCopyFilter

Stop DeepCopy from recursively copying element, using standard clone instead:

use DeepCopy\DeepCopy;
use DeepCopy\TypeFilter\ShallowCopyFilter;
use DeepCopy\TypeMatcher\TypeMatcher;
use Mockery as m;

$this->deepCopy = new DeepCopy();
$this->deepCopy->addTypeFilter(
	new ShallowCopyFilter,
	new TypeMatcher(m\MockInterface::class)
);

$myServiceWithMocks = new MyService(m::mock(MyDependency1::class), m::mock(MyDependency2::class));
// all mocks will be just cloned, not deep-copied 

DoctrineCollectionFilter

If you use Doctrine and want to copy an entity, you will need to use the DoctrineCollectionFilter:

use DeepCopy\DeepCopy;
use DeepCopy\Filter\Doctrine\DoctrineCollectionFilter;
use DeepCopy\Matcher\PropertyTypeMatcher;

$deepCopy = new DeepCopy();
$deepCopy->addFilter(new DoctrineCollectionFilter(), new PropertyTypeMatcher('Doctrine\Common\Collections\Collection'));
$myCopy = $deepCopy->copy($myObject);

DoctrineEmptyCollectionFilter

If you use Doctrine and want to copy an entity who contains a Collection that you want to be reset, you can use the DoctrineEmptyCollectionFilter

use DeepCopy\DeepCopy;
use DeepCopy\Filter\Doctrine\DoctrineEmptyCollectionFilter;
use DeepCopy\Matcher\PropertyMatcher;

$deepCopy = new DeepCopy();
$deepCopy->addFilter(new DoctrineEmptyCollectionFilter(), new PropertyMatcher('MyClass', 'myProperty'));
$myCopy = $deepCopy->copy($myObject);

// $myCopy->myProperty will return an empty collection

Contributing

DeepCopy is distributed under the MIT license.

Tests

Running the tests is simple:

phpunit