1: <?php
 2: /**
 3:  * CakePHP(tm) : Rapid Development Framework (https://cakephp.org)
 4:  * Copyright (c) Cake Software Foundation, Inc. (https://cakefoundation.org)
 5:  *
 6:  * Licensed under The MIT License
 7:  * For full copyright and license information, please see the LICENSE.txt
 8:  * Redistributions of files must retain the above copyright notice.
 9:  *
10:  * @copyright     Copyright (c) Cake Software Foundation, Inc. (https://cakefoundation.org)
11:  * @link          https://cakephp.org CakePHP(tm) Project
12:  * @since         3.0.0
13:  * @license       https://opensource.org/licenses/mit-license.php MIT License
14:  */
15: namespace Cake\I18n;
16: 
17: use Aura\Intl\Package;
18: use RuntimeException;
19: 
20: /**
21:  * Wraps multiple message loaders calling them one after another until
22:  * one of them returns a non-empty package.
23:  */
24: class ChainMessagesLoader
25: {
26: 
27:     /**
28:      * The list of callables to execute one after another for loading messages
29:      *
30:      * @var callable[]
31:      */
32:     protected $_loaders = [];
33: 
34:     /**
35:      * Receives a list of callable functions or objects that will be executed
36:      * one after another until one of them returns a non-empty translations package
37:      *
38:      * @param callable[] $loaders List of callables to execute
39:      */
40:     public function __construct(array $loaders)
41:     {
42:         $this->_loaders = $loaders;
43:     }
44: 
45:     /**
46:      * Executes this object returning the translations package as configured in
47:      * the chain.
48:      *
49:      * @return \Aura\Intl\Package
50:      * @throws \RuntimeException if any of the loaders in the chain is not a valid callable
51:      */
52:     public function __invoke()
53:     {
54:         foreach ($this->_loaders as $k => $loader) {
55:             if (!is_callable($loader)) {
56:                 throw new RuntimeException(sprintf(
57:                     'Loader "%s" in the chain is not a valid callable',
58:                     $k
59:                 ));
60:             }
61: 
62:             $package = $loader();
63:             if (!$package) {
64:                 continue;
65:             }
66: 
67:             if (!($package instanceof Package)) {
68:                 throw new RuntimeException(sprintf(
69:                     'Loader "%s" in the chain did not return a valid Package object',
70:                     $k
71:                 ));
72:             }
73: 
74:             return $package;
75:         }
76: 
77:         return new Package();
78:     }
79: }
80: