1<?php
2/**
3 * Copyright 2017 Facebook, Inc.
4 *
5 * You are hereby granted a non-exclusive, worldwide, royalty-free license to
6 * use, copy, modify, and distribute this software in source code or binary
7 * form for use in connection with the web services and APIs provided by
8 * Facebook.
9 *
10 * As with any software that integrates with the Facebook platform, your use
11 * of this software is subject to the Facebook Developer Principles and
12 * Policies [http://developers.facebook.com/policy/]. This copyright notice
13 * shall be included in all copies or substantial portions of the software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
21 * DEALINGS IN THE SOFTWARE.
22 *
23 */
24
25/**
26 * You only need this file if you are not using composer.
27 * Why are you not using composer?
28 * https://getcomposer.org/
29 */
30
31if (version_compare(PHP_VERSION, '5.4.0', '<')) {
32    throw new Exception('The Facebook SDK requires PHP version 5.4 or higher.');
33}
34
35require_once __DIR__ . '/polyfills.php';
36
37/**
38 * Register the autoloader for the Facebook SDK classes.
39 *
40 * Based off the official PSR-4 autoloader example found here:
41 * https://github.com/php-fig/fig-standards/blob/master/accepted/PSR-4-autoloader-examples.md
42 *
43 * @param string $class The fully-qualified class name.
44 *
45 * @return void
46 */
47spl_autoload_register(function ($class) {
48    // project-specific namespace prefix
49    $prefix = 'Facebook\\';
50
51    // For backwards compatibility
52    $customBaseDir = '';
53    // @todo v6: Remove support for 'FACEBOOK_SDK_V4_SRC_DIR'
54    if (defined('FACEBOOK_SDK_V4_SRC_DIR')) {
55        $customBaseDir = FACEBOOK_SDK_V4_SRC_DIR;
56    } elseif (defined('FACEBOOK_SDK_SRC_DIR')) {
57        $customBaseDir = FACEBOOK_SDK_SRC_DIR;
58    }
59    // base directory for the namespace prefix
60    $baseDir = $customBaseDir ?: __DIR__ . '/';
61
62    // does the class use the namespace prefix?
63    $len = strlen($prefix);
64    if (strncmp($prefix, $class, $len) !== 0) {
65        // no, move to the next registered autoloader
66        return;
67    }
68
69    // get the relative class name
70    $relativeClass = substr($class, $len);
71
72    // replace the namespace prefix with the base directory, replace namespace
73    // separators with directory separators in the relative class name, append
74    // with .php
75    $file = rtrim($baseDir, '/') . '/' . str_replace('\\', '/', $relativeClass) . '.php';
76
77    // if the file exists, require it
78    if (file_exists($file)) {
79        require $file;
80    }
81});
82