feature #18332 [Form] added CallbackChoiceLoader and refactored Cho…

…iceType's children (HeahDude)

This PR was merged into the 3.2-dev branch.

Discussion
----------

[Form] added `CallbackChoiceLoader` and refactored ChoiceType's children

| Q             | A
| ------------- | ---
| Branch?       | master
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | ~
| License       | MIT
| Doc PR        | todo

Todo
====
- [ ] Address a doc PR
- [x] Update CHANGELOG

Changes
=======
 - 39e937f added `CallbackChoiceLoader` to lazy load choices with a simple callable.

 - 995dc56 refactored `CountryType`, `CurrencyType`, `LanguageType`, `LocaleType` and `TimezoneType` for better performance by implementing `ChoiceLoaderInterface` for lazy loading.

Usage
=====
```php
use Symfony\Component\Form\ChoiceList\Loader\CallbackChoiceLoader;
use Symfony\Component\Form\Extension\Core\Type\ChoiceType;

$builder->add('constants', ChoiceType::class, array(
    'choice_loader' => new CallbackChoiceLoader(function() {
            return StaticClass::getConstants();
    },
));
```

Commits
-------

8a4e164 [Form] implemented ChoiceLoaderInterface in children of ChoiceType
afd7bf8 [Form] added `CallbackChoiceLoader`

src/Symfony/Component/Form/CHANGELOG.md

@@ -1,6 +1,12 @@
 CHANGELOG
 =========
 
+3.2.0
+-----
+
+ * added `CallbackChoiceLoader`
+ * implemented `ChoiceLoaderInterface` in children of `ChoiceType`
+
 3.1.0
 -----
 

src/Symfony/Component/Form/ChoiceList/Loader/CallbackChoiceLoader.php

@@ -0,0 +1,77 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Form\ChoiceList\Loader;
+
+use Symfony\Component\Form\ChoiceList\ArrayChoiceList;
+
+/**
+ * Loads an {@link ArrayChoiceList} instance from a callable returning an array of choices.
+ *
+ * @author Jules Pietri <jules@heahprod.com>
+ */
+class CallbackChoiceLoader implements ChoiceLoaderInterface
+{
+    private $callback;
+
+    /**
+     * The loaded choice list.
+     *
+     * @var ArrayChoiceList
+     */
+    private $choiceList;
+
+    /**
+     * @param callable $callback The callable returning an array of choices
+     */
+    public function __construct(callable $callback)
+    {
+        $this->callback = $callback;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function loadChoiceList($value = null)
+    {
+        if (null !== $this->choiceList) {
+            return $this->choiceList;
+        }
+
+        return $this->choiceList = new ArrayChoiceList(call_user_func($this->callback), $value);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function loadChoicesForValues(array $values, $value = null)
+    {
+        // Optimize
+        if (empty($values)) {
+            return array();
+        }
+
+        return $this->loadChoiceList($value)->getChoicesForValues($values);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function loadValuesForChoices(array $choices, $value = null)
+    {
+        // Optimize
+        if (empty($choices)) {
+            return array();
+        }
+
+        return $this->loadChoiceList($value)->getValuesForChoices($choices);
+    }
+}

src/Symfony/Component/Form/Extension/Core/Type/CountryType.php

@@ -12,18 +12,31 @@
 namespace Symfony\Component\Form\Extension\Core\Type;
 
 use Symfony\Component\Form\AbstractType;
+use Symfony\Component\Form\ChoiceList\ArrayChoiceList;
+use Symfony\Component\Form\ChoiceList\Loader\ChoiceLoaderInterface;
 use Symfony\Component\Intl\Intl;
 use Symfony\Component\OptionsResolver\OptionsResolver;
 
-class CountryType extends AbstractType
+class CountryType extends AbstractType implements ChoiceLoaderInterface
 {
+    /**
+     * Country loaded choice list.
+     *
+     * The choices are lazy loaded and generated from the Intl component.
+     *
+     * {@link \Symfony\Component\Intl\Intl::getRegionBundle()}.
+     *
+     * @var ArrayChoiceList
+     */
+    private $choiceList;
+
     /**
      * {@inheritdoc}
      */
     public function configureOptions(OptionsResolver $resolver)
     {
         $resolver->setDefaults(array(
-            'choices' => array_flip(Intl::getRegionBundle()->getCountryNames()),
+            'choice_loader' => $this,
             'choice_translation_domain' => false,
         ));
     }
@@ -43,4 +56,52 @@ public function getBlockPrefix()
     {
         return 'country';
     }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function loadChoiceList($value = null)
+    {
+        if (null !== $this->choiceList) {
+            return $this->choiceList;
+        }
+
+        return $this->choiceList = new ArrayChoiceList(array_flip(Intl::getRegionBundle()->getCountryNames()), $value);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function loadChoicesForValues(array $values, $value = null)
+    {
+        // Optimize
+        if (empty($values)) {
+            return array();
+        }
+
+        // If no callable is set, values are the same as choices
+        if (null === $value) {
+            return $values;
+        }
+
+        return $this->loadChoiceList($value)->getChoicesForValues($values);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function loadValuesForChoices(array $choices, $value = null)
+    {
+        // Optimize
+        if (empty($choices)) {
+            return array();
+        }
+
+        // If no callable is set, choices are the same as values
+        if (null === $value) {
+            return $choices;
+        }
+
+        return $this->loadChoiceList($value)->getValuesForChoices($choices);
+    }
 }

src/Symfony/Component/Form/Extension/Core/Type/CurrencyType.php

@@ -12,18 +12,31 @@
 namespace Symfony\Component\Form\Extension\Core\Type;
 
 use Symfony\Component\Form\AbstractType;
+use Symfony\Component\Form\ChoiceList\ArrayChoiceList;
+use Symfony\Component\Form\ChoiceList\Loader\ChoiceLoaderInterface;
 use Symfony\Component\Intl\Intl;
 use Symfony\Component\OptionsResolver\OptionsResolver;
 
-class CurrencyType extends AbstractType
+class CurrencyType extends AbstractType implements ChoiceLoaderInterface
 {
+    /**
+     * Currency loaded choice list.
+     *
+     * The choices are lazy loaded and generated from the Intl component.
+     *
+     * {@link \Symfony\Component\Intl\Intl::getCurrencyBundle()}.
+     *
+     * @var ArrayChoiceList
+     */
+    private $choiceList;
+
     /**
      * {@inheritdoc}
      */
     public function configureOptions(OptionsResolver $resolver)
     {
         $resolver->setDefaults(array(
-            'choices' => array_flip(Intl::getCurrencyBundle()->getCurrencyNames()),
+            'choice_loader' => $this,
             'choice_translation_domain' => false,
         ));
     }
@@ -43,4 +56,52 @@ public function getBlockPrefix()
     {
         return 'currency';
     }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function loadChoiceList($value = null)
+    {
+        if (null !== $this->choiceList) {
+            return $this->choiceList;
+        }
+
+        return $this->choiceList = new ArrayChoiceList(array_flip(Intl::getCurrencyBundle()->getCurrencyNames()), $value);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function loadChoicesForValues(array $values, $value = null)
+    {
+        // Optimize
+        if (empty($values)) {
+            return array();
+        }
+
+        // If no callable is set, values are the same as choices
+        if (null === $value) {
+            return $values;
+        }
+
+        return $this->loadChoiceList($value)->getChoicesForValues($values);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function loadValuesForChoices(array $choices, $value = null)
+    {
+        // Optimize
+        if (empty($choices)) {
+            return array();
+        }
+
+        // If no callable is set, choices are the same as values
+        if (null === $value) {
+            return $choices;
+        }
+
+        return $this->loadChoiceList($value)->getValuesForChoices($choices);
+    }
 }

src/Symfony/Component/Form/Extension/Core/Type/LanguageType.php

@@ -12,18 +12,31 @@
 namespace Symfony\Component\Form\Extension\Core\Type;
 
 use Symfony\Component\Form\AbstractType;
+use Symfony\Component\Form\ChoiceList\ArrayChoiceList;
+use Symfony\Component\Form\ChoiceList\Loader\ChoiceLoaderInterface;
 use Symfony\Component\Intl\Intl;
 use Symfony\Component\OptionsResolver\OptionsResolver;
 
-class LanguageType extends AbstractType
+class LanguageType extends AbstractType implements ChoiceLoaderInterface
 {
+    /**
+     * Language loaded choice list.
+     *
+     * The choices are lazy loaded and generated from the Intl component.
+     *
+     * {@link \Symfony\Component\Intl\Intl::getLanguageBundle()}.
+     *
+     * @var ArrayChoiceList
+     */
+    private $choiceList;
+
     /**
      * {@inheritdoc}
      */
     public function configureOptions(OptionsResolver $resolver)
     {
         $resolver->setDefaults(array(
-            'choices' => array_flip(Intl::getLanguageBundle()->getLanguageNames()),
+            'choice_loader' => $this,
             'choice_translation_domain' => false,
         ));
     }
@@ -43,4 +56,52 @@ public function getBlockPrefix()
     {
         return 'language';
     }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function loadChoiceList($value = null)
+    {
+        if (null !== $this->choiceList) {
+            return $this->choiceList;
+        }
+
+        return $this->choiceList = new ArrayChoiceList(array_flip(Intl::getLanguageBundle()->getLanguageNames()), $value);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function loadChoicesForValues(array $values, $value = null)
+    {
+        // Optimize
+        if (empty($values)) {
+            return array();
+        }
+
+        // If no callable is set, values are the same as choices
+        if (null === $value) {
+            return $values;
+        }
+
+        return $this->loadChoiceList($value)->getChoicesForValues($values);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function loadValuesForChoices(array $choices, $value = null)
+    {
+        // Optimize
+        if (empty($choices)) {
+            return array();
+        }
+
+        // If no callable is set, choices are the same as values
+        if (null === $value) {
+            return $choices;
+        }
+
+        return $this->loadChoiceList($value)->getValuesForChoices($choices);
+    }
 }