Cron.php

<?php
/**
 * WP Cron job container.
 */
class scbCron {
	protected $schedule;
	protected $interval;
	protected $time;

	protected $hook;
	protected $callback_args = array();

	/**
	 * Create a new cron job.
	 *
	 * @param string|bool $file (optional) Reference to main plugin file
	 * @param array       $args List of args:
	 *                          string $action OR callback $callback
	 *                          string $schedule OR number $interval
	 *                          array $callback_args (optional)
	 *
	 * @return void
	 */
	public function __construct( $file = false, $args ) {

		// Set time & schedule
		if ( isset( $args['time'] ) ) {
			$this->time = $args['time'];
		}

		if ( isset( $args['interval'] ) ) {
			$this->schedule = $args['interval'] . 'secs';
			$this->interval = $args['interval'];
		} elseif ( isset( $args['schedule'] ) ) {
			$this->schedule = $args['schedule'];
		}

		// Set hook
		if ( isset( $args['action'] ) ) {
			$this->hook = $args['action'];
		} else if ( isset( $args['callback'] ) ) {
			$this->hook = self::_callback_to_string( $args['callback'] );
			add_action( $this->hook, $args['callback'] );
		} else if ( method_exists( $this, 'callback' ) ) {
			$this->hook = self::_callback_to_string( array( $this, 'callback' ) );
			add_action( $this->hook, $args['callback'] );
		} else {
			trigger_error( '$action OR $callback not set', E_USER_WARNING );
		}

		if ( isset( $args['callback_args'] ) ) {
			$this->callback_args = (array) $args['callback_args'];
		}

		if ( $file && $this->schedule ) {
			scbUtil::add_activation_hook( $file, array( $this, 'reset' ) );
			register_deactivation_hook( $file, array( $this, 'unschedule' ) );
		}

		add_filter( 'cron_schedules', array( $this, '_add_timing' ) );
	}

	/**
	 * Change the interval of the cron job.
	 *
	 * @param array $args List of args:
	 *                    string $schedule OR number $interval
	 *                    timestamp $time ( optional )
	 *
	 * @return void
	 */
	public function reschedule( $args ) {

		if ( $args['schedule'] && $this->schedule != $args['schedule'] ) {
			$this->schedule = $args['schedule'];
		} elseif ( $args['interval'] && $this->interval != $args['interval'] ) {
			$this->schedule = $args['interval'] . 'secs';
			$this->interval = $args['interval'];
		}

		$this->time = $args['time'];

		$this->reset();
	}

	/**
	 * Reset the schedule.
	 *
	 * @return void
	 */
	public function reset() {
		$this->unschedule();
		$this->schedule();
	}

	/**
	 * Clear the cron job.
	 *
	 * @return void
	 */
	public function unschedule() {
#		wp_clear_scheduled_hook( $this->hook, $this->callback_args );
		self::really_clear_scheduled_hook( $this->hook );
	}

	/**
	 * Execute the job now.
	 *
	 * @param array $args (optional) List of arguments to pass to the callback.
	 *
	 * @return void
	 */
	public function do_now( $args = null ) {
		if ( is_null( $args ) ) {
			$args = $this->callback_args;
		}

		do_action_ref_array( $this->hook, $args );
	}

	/**
	 * Execute the job with a given delay.
	 *
	 * @param int   $delay (optional) Delay in seconds.
	 * @param array $args  (optional) List of arguments to pass to the callback.
	 *
	 * @return void
	 */
	public function do_once( $delay = 0, $args = null ) {
		if ( is_null( $args ) ) {
			$args = $this->callback_args;
		}

		wp_clear_scheduled_hook( $this->hook, $args );
		wp_schedule_single_event( time() + $delay, $this->hook, $args );
	}


//_____INTERNAL METHODS_____

	/**
	 * Adds custom schedule timing.
	 *
	 * @param array $schedules
	 *
	 * @return array
	 */
	public function _add_timing( $schedules ) {
		if ( isset( $schedules[ $this->schedule ] ) ) {
			return $schedules;
		}

		$schedules[ $this->schedule ] = array(
			'interval' => $this->interval,
			'display'  => $this->interval . ' seconds',
		);

		return $schedules;
	}

	/**
	 * Schedule the job.
	 *
	 * @return void
	 */
	protected function schedule() {
		if ( ! $this->time ) {
			$this->time = time();
		}

		wp_schedule_event( $this->time, $this->schedule, $this->hook, $this->callback_args );
	}

	/**
	 * Clears scheduled job.
	 *
	 * @param string $name
	 *
	 * @return void
	 */
	protected static function really_clear_scheduled_hook( $name ) {
		$crons = _get_cron_array();

		foreach ( $crons as $timestamp => $hooks ) {
			foreach ( $hooks as $hook => $args ) {
				if ( $hook == $name ) {
					unset( $crons[ $timestamp ][ $hook ] );
				}
			}

			if ( empty( $crons[ $timestamp ] ) ) {
				unset( $crons[ $timestamp ] );
			}
		}

		_set_cron_array( $crons );
	}

	/**
	 * Generates a hook name from given callback.
	 *
	 * @param callback $callback
	 *
	 * @return string
	 */
	protected static function _callback_to_string( $callback ) {
		if ( ! is_array( $callback ) ) {
			$str = $callback;
		} else if ( ! is_string( $callback[0] ) ) {
			$str = get_class( $callback[0] ) . '_' . $callback[1];
		} else {
			$str = $callback[0] . '::' . $callback[1];
		}

		$str .= '_hook';

		return $str;
	}
}