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# DeepCopy DeepCopy helps you create deep copies (clones) of your objects. It is designed to handle cycles in the association graph. [](https://travis-ci.org/myclabs/DeepCopy) [](https://coveralls.io/r/myclabs/DeepCopy?branch=master) [](https://scrutinizer-ci.com/g/myclabs/DeepCopy/) [](https://packagist.org/packages/myclabs/deep-copy) ## Table of Contents 1. [How](#how) 1. [Why](#why) 1. [Using simply `clone`](#using-simply-clone) 1. [Overridding `__clone()`](#overridding-__clone) 1. [With `DeepCopy`](#with-deepcopy) 1. [How it works](#how-it-works) 1. [Going further](#going-further) 1. [Matchers](#matchers) 1. [Property name](#property-name) 1. [Specific property](#specific-property) 1. [Type](#type) 1. [Filters](#filters) 1. [`SetNullFilter`](#setnullfilter-filter) 1. [`KeepFilter`](#keepfilter-filter) 1. [`DoctrineCollectionFilter`](#doctrinecollectionfilter-filter) 1. [`DoctrineEmptyCollectionFilter`](#doctrineemptycollectionfilter-filter) 1. [`DoctrineProxyFilter`](#doctrineproxyfilter-filter) 1. [`ReplaceFilter`](#replacefilter-type-filter) 1. [`ShallowCopyFilter`](#doctrinecollectionfilter-type-filter) 1. [Edge cases](#edge-cases) 1. [Contributing](#contributing) 1. [Tests](#tests) ## How? Install with Composer: ```json composer require myclabs/deep-copy ``` Use simply: ```php use DeepCopy\DeepCopy; $copier = new DeepCopy(); $myCopy = $copier->copy($myObject); ``` ## Why? - How do you create copies of your objects? ```php $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()`](http://www.php.net/manual/en/language.oop5.cloning.php#object.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 recursively traverses all the object's properties and clones them. To avoid cloning the same object twice it keeps a hash map of all instances and thus preserves the object graph. To use it: ```php use function DeepCopy\deep_copy; $copy = deep_copy($var); ``` Alternatively, you can create your own `DeepCopy` instance to configure it differently for example: ```php use DeepCopy\DeepCopy; $copier = new DeepCopy(true); $copy = $copier->copy($var); ``` You may want to roll your own deep copy function: ```php namespace Acme; use DeepCopy\DeepCopy; function deep_copy($var) { static $copier = null; if (null === $copier) { $copier = new DeepCopy(true); } return $copier->copy($var); } ``` ## Going further You can add filters to customize the copy process. The method to add a filter is `DeepCopy\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: ```php use DeepCopy\Matcher\PropertyNameMatcher; // Will apply a filter to any property of any objects named "id" $matcher = new PropertyNameMatcher('id'); ``` #### Specific property The `PropertyMatcher` will match a specific property of a specific class: ```php use DeepCopy\Matcher\PropertyMatcher; // Will apply a filter to the property "id" of any objects of the class "MyClass" $matcher = new PropertyMatcher('MyClass', 'id'); ``` #### Type The `TypeMatcher` will match any element by its type (instance of a class or any value that could be parameter of [gettype()](http://php.net/manual/en/function.gettype.php) function): ```php use DeepCopy\TypeMatcher\TypeMatcher; // Will apply a filter to any object that is an instance of Doctrine\Common\Collections\Collection $matcher = new TypeMatcher('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` (filter) 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: ```php use DeepCopy\DeepCopy; use DeepCopy\Filter\SetNullFilter; use DeepCopy\Matcher\PropertyNameMatcher; $object = MyClass::load(123); echo $object->id; // 123 $copier = new DeepCopy(); $copier->addFilter(new SetNullFilter(), new PropertyNameMatcher('id')); $copy = $copier->copy($object); echo $copy->id; // null ``` #### `KeepFilter` (filter) If you want a property to remain untouched (for example, an association to an object): ```php use DeepCopy\DeepCopy; use DeepCopy\Filter\KeepFilter; use DeepCopy\Matcher\PropertyMatcher; $copier = new DeepCopy(); $copier->addFilter(new KeepFilter(), new PropertyMatcher('MyClass', 'category')); $copy = $copier->copy($object); // $copy->category has not been touched ``` #### `DoctrineCollectionFilter` (filter) If you use Doctrine and want to copy an entity, you will need to use the `DoctrineCollectionFilter`: ```php use DeepCopy\DeepCopy; use DeepCopy\Filter\Doctrine\DoctrineCollectionFilter; use DeepCopy\Matcher\PropertyTypeMatcher; $copier = new DeepCopy(); $copier->addFilter(new DoctrineCollectionFilter(), new PropertyTypeMatcher('Doctrine\Common\Collections\Collection')); $copy = $copier->copy($object); ``` #### `DoctrineEmptyCollectionFilter` (filter) 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` ```php use DeepCopy\DeepCopy; use DeepCopy\Filter\Doctrine\DoctrineEmptyCollectionFilter; use DeepCopy\Matcher\PropertyMatcher; $copier = new DeepCopy(); $copier->addFilter(new DoctrineEmptyCollectionFilter(), new PropertyMatcher('MyClass', 'myProperty')); $copy = $copier->copy($object); // $copy->myProperty will return an empty collection ``` #### `DoctrineProxyFilter` (filter) If you use Doctrine and use cloning on lazy loaded entities, you might encounter errors mentioning missing fields on a Doctrine proxy class (...\\\_\_CG\_\_\Proxy). You can use the `DoctrineProxyFilter` to load the actual entity behind the Doctrine proxy class. **Make sure, though, to put this as one of your very first filters in the filter chain so that the entity is loaded before other filters are applied!** ```php use DeepCopy\DeepCopy; use DeepCopy\Filter\Doctrine\DoctrineProxyFilter; use DeepCopy\Matcher\Doctrine\DoctrineProxyMatcher; $copier = new DeepCopy(); $copier->addFilter(new DoctrineProxyFilter(), new DoctrineProxyMatcher()); $copy = $copier->copy($object); // $copy should now contain a clone of all entities, including those that were not yet fully loaded. ``` #### `ReplaceFilter` (type filter) 1. If you w