polr/vendor/myclabs/deep-copy/README.md

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

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"

Property type

The PropertyTypeMatcher will match a property by its type (instance of a class):

use DeepCopy\Matcher\PropertyTypeMatcher;

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

Filters

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

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)'

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

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