Introduce method to store cron events in a CPT instead of an option, to avoid race conditions

Still need to:
* deal with unscheduling events
* ensure all events are captured (Jetpack/VaultPress seem to be missing)

includes/class-cron-options-cpt.php

@@ -23,13 +23,19 @@ class Cron_Options_CPT {
 	/**
 	 * Class properties
 	 */
-	private $post_type = 'wpccr_events';
+	private $post_type   = 'wpccr_events';
+	private $post_status = 'inherit';
 
 	/**
 	 * Register hooks
 	 */
 	private function __construct() {
+		// Data storage
 		add_action( 'init', array( $this, 'register_post_type' ) );
+
+		// Option interception
+		add_filter( 'pre_option_cron', array( $this, 'get_option' ) );
+		add_filter( 'pre_update_option_cron', array( $this, 'update_option' ), 10, 2 );
 	}
 
 	/**
@@ -48,6 +54,138 @@ class Cron_Options_CPT {
 	/**
 	 * PLUGIN FUNCTIONALITY
 	 */
+
+	/**
+	 * Override cron option requests with data from CPT
+	 */
+	public function get_option( $value ) {
+		$cron_array = array(
+			'version' => 2, // Core versions the cron array; without this, events will continually requeue
+		);
+
+		// Get events to re-render as the cron option
+		$jobs_posts = get_posts( array(
+			'post_type'        => $this->post_type,
+			'post_status'      => $this->post_status,
+			'suppress_filters' => false,
+			'posts_per_page'   => 1000,
+		) );
+
+		// Loop through results and built output Core expects
+		if ( ! empty( $jobs_posts ) ) {
+			foreach ( $jobs_posts as $jobs_post ) {
+				$timestamp = strtotime( $jobs_post->post_date_gmt );
+
+				$job_args = maybe_unserialize( $jobs_post->post_content_filtered );
+				if ( ! is_array( $job_args ) ) {
+					continue;
+				}
+
+				$action   = $job_args['action'];
+				$instance = $job_args['instance'];
+				$args     = $job_args['args'];
+
+				$cron_array[ $timestamp ][ $action ][ $instance ] = array(
+					'schedule' => $args['schedule'],
+					'args'     => $args['args'],
+				);
+
+				if ( isset( $args['interval'] ) ) {
+					$cron_array[ $timestamp ][ $action ][ $instance ]['interval'] = $args['interval'];
+				}
+
+			}
+		}
+
+		uksort( $cron_array, "strnatcasecmp" );
+
+		return $cron_array;
+	}
+
+	/**
+	 * Save cron events in CPT
+	 *
+	 * By returning $old_value, `cron` option won't be updated
+	 */
+	public function update_option( $new_value, $old_value ) {
+		if ( is_array( $new_value ) && ! empty( $new_value ) ) {
+			foreach ( $new_value as $timestamp => $timestamp_events ) {
+				// Skip non-event data that Core includes in the option
+				if ( ! is_numeric( $timestamp ) ) {
+					continue;
+				}
+
+				foreach ( $timestamp_events as $action => $action_instances ) {
+					foreach ( $action_instances as $instance => $instance_args ) {
+						// There are some jobs we never care to run
+						if ( is_blocked_event( $action ) ) {
+							continue;
+						}
+
+						// Check if post exists and bail
+						$job_exists = get_posts( array(
+							'name'             => sprintf( '%s-%s-%s', $timestamp, md5( $action ), $instance ),
+							'post_type'        => $this->post_type,
+							'post_status'      => $this->post_status,
+							'suppress_filters' => false,
+							'posts_per_page'   => 1,
+						) );
+
+						// Create a post, if needed
+						if ( empty( $job_exists ) ) {
+							$job_args = array(
+								'action'   => $action,
+								'instance' => $instance,
+								'args'     => $instance_args,
+							);
+
+							wp_insert_post( array(
+								'post_title'            => sprintf( '%s | %s | %s', $timestamp, $action, $instance ),
+								'post_name'             => sprintf( '%s-%s-%s', $timestamp, md5( $action ), $instance ),
+								'post_content_filtered' => maybe_serialize( $job_args ),
+								'post_date'             => date( 'Y-m-d H:i:s', $timestamp ),
+								'post_date_gmt'         => date( 'Y-m-d H:i:s', $timestamp ),
+								'post_type'             => $this->post_type,
+								'post_status'           => $this->post_status,
+							) );
+						}
+					}
+				}
+			}
+		}
+
+		return $old_value;
+	}
+
+	/**
+	 * PLUGIN UTILITY METHODS
+	 */
+
+	/**
+	 * Remove an event's CPT entry
+	 *
+	 * @param $timestamp  int     Unix timestamp
+	 * @param $action     string  name of action used when the event is registered (unhashed)
+	 * @param $instance   string  md5 hash of the event's arguments array, which Core uses to index the `cron` option
+	 *
+	 * @return bool
+	 */
+	public function delete_event( $timestamp, $action, $instance ) {
+		$job_exists = get_posts( array(
+			'name'             => sprintf( '%s-%s-%s', $timestamp, md5( $action ), $instance ),
+			'post_type'        => $this->post_type,
+			'post_status'      => $this->post_status,
+			'suppress_filters' => false,
+			'posts_per_page'   => 1,
+		) );
+
+		if ( empty( $job_exists ) ) {
+			return false;
+		}
+
+		wp_delete_post( $job_exists[0]->ID, true );
+		return true;
+	}
 }
 
 Cron_Options_CPT::instance();

includes/functions.php

@@ -8,3 +8,16 @@ namespace WP_Cron_Control_Revisited;
 function get_plugin_var( $variable ) {
 	return property_exists( Main::instance(), $variable ) ? Main::instance()->$variable : null;
 }
+
+/**
+ * Delete an event
+ *
+ * @param $timestamp  int     Unix timestamp
+ * @param $action     string  name of action used when the event is registered (unhashed)
+ * @param $instance   string  md5 hash of the event's arguments array, which Core uses to index the `cron` option
+ *
+ * @return bool
+ */
+function delete_cron_event( $timestamp, $action, $instance ) {
+	return Cron_Options_CPT::instance()->delete_event( $timestamp, $action, $instance );
+}

wp-cron-control-revisited.php

@@ -248,6 +248,7 @@ class Main {
 		}
 
 		wp_unschedule_event( $event['timestamp'], $event['action'], $event['args'] );
+		delete_cron_event( $event['timestamp'], $event['action'], $event['instance'] );
 
 		// Run the event
 		do_action_ref_array( $event['action'], $event['args'] );
@@ -280,6 +281,7 @@ class Main {
 					$event              = $action_events[ $instance ];
 					$event['timestamp'] = $timestamp;
 					$event['action']    = $action;
+					$event['instance']  = $instance;
 					break;
 				}
 			}