<?php

/**

 * Polyfill for SPL autoload feature. This file is separate to prevent compiler notices

 * on the deprecated __autoload() function.

 *

 * See https://core.trac.wordpress.org/ticket/41134

 *

 * @package PHP

 * @access private

 */

if ( ! function_exists( 'spl_autoload_register' ) ) {

	$_wp_spl_autoloaders = array();

	/**

	 * Autoloader compatibility callback.

	 *

	 * @since 4.6.0

	 *

	 * @param string $classname Class to attempt autoloading.

	 */

	function __autoload( $classname ) {

		global $_wp_spl_autoloaders;

		foreach ( $_wp_spl_autoloaders as $autoloader ) {

			if ( ! is_callable( $autoloader ) ) {

				// Avoid the extra warning if the autoloader isn't callable.

				continue;

			}

			call_user_func( $autoloader, $classname );

			// If it has been autoloaded, stop processing.

			if ( class_exists( $classname, false ) ) {

				return;

			}

		}

	}

	/**

	 * Registers a function to be autoloaded.

	 *

	 * @since 4.6.0

	 *

	 * @param callable $autoload_function The function to register.

	 * @param bool     $throw             Optional. Whether the function should throw an exception

	 *                                    if the function isn't callable. Default true.

	 * @param bool     $prepend           Whether the function should be prepended to the stack.

	 *                                    Default false.

	 */

	function spl_autoload_register( $autoload_function, $throw = true, $prepend = false ) {

		if ( $throw && ! is_callable( $autoload_function ) ) {

			// String not translated to match PHP core.

			throw new Exception( 'Function not callable' );

		}

		global $_wp_spl_autoloaders;

		// Don't allow multiple registration.

		if ( in_array( $autoload_function, $_wp_spl_autoloaders ) ) {

			return;

		}

		if ( $prepend ) {

			array_unshift( $_wp_spl_autoloaders, $autoload_function );

		} else {

			$_wp_spl_autoloaders[] = $autoload_function;

		}

	}

	/**

	 * Unregisters an autoloader function.

	 *

	 * @since 4.6.0

	 *

	 * @param callable $function The function to unregister.

	 * @return bool True if the function was unregistered, false if it could not be.

	 */

	function spl_autoload_unregister( $function ) {

		global $_wp_spl_autoloaders;

		foreach ( $_wp_spl_autoloaders as &$autoloader ) {

			if ( $autoloader === $function ) {

				unset( $autoloader );

				return true;

			}

		}

		return false;

	}

	/**

	 * Retrieves the registered autoloader functions.

	 *

	 * @since 4.6.0

	 *

	 * @return array List of autoloader functions.

	 */

	function spl_autoload_functions() {

		return $GLOBALS['_wp_spl_autoloaders'];

	}

}