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:      * The list of callables to execute one after another for loading messages
28:      *
29:      * @var callable[]
30:      */
31:     protected $_loaders = [];
32: 
33:     /**
34:      * Receives a list of callable functions or objects that will be executed
35:      * one after another until one of them returns a non-empty translations package
36:      *
37:      * @param callable[] $loaders List of callables to execute
38:      */
39:     public function __construct(array $loaders)
40:     {
41:         $this->_loaders = $loaders;
42:     }
43: 
44:     /**
45:      * Executes this object returning the translations package as configured in
46:      * the chain.
47:      *
48:      * @return \Aura\Intl\Package
49:      * @throws \RuntimeException if any of the loaders in the chain is not a valid callable
50:      */
51:     public function __invoke()
52:     {
53:         foreach ($this->_loaders as $k => $loader) {
54:             if (!is_callable($loader)) {
55:                 throw new RuntimeException(sprintf(
56:                     'Loader "%s" in the chain is not a valid callable',
57:                     $k
58:                 ));
59:             }
60: 
61:             $package = $loader();
62:             if (!$package) {
63:                 continue;
64:             }
65: 
66:             if (!($package instanceof Package)) {
67:                 throw new RuntimeException(sprintf(
68:                     'Loader "%s" in the chain did not return a valid Package object',
69:                     $k
70:                 ));
71:             }
72: 
73:             return $package;
74:         }
75: 
76:         return new Package();
77:     }
78: }
79: