diff options
Diffstat (limited to 'plugins/jetpack/jetpack_vendor/automattic/jetpack-sync/src/class-queue.php')
| -rw-r--r-- | plugins/jetpack/jetpack_vendor/automattic/jetpack-sync/src/class-queue.php | 744 |
1 files changed, 744 insertions, 0 deletions
diff --git a/plugins/jetpack/jetpack_vendor/automattic/jetpack-sync/src/class-queue.php b/plugins/jetpack/jetpack_vendor/automattic/jetpack-sync/src/class-queue.php new file mode 100644 index 00000000..fe80cf90 --- /dev/null +++ b/plugins/jetpack/jetpack_vendor/automattic/jetpack-sync/src/class-queue.php @@ -0,0 +1,744 @@ +<?php +/** + * The class that describes the Queue for the sync package. + * + * @package automattic/jetpack-sync + */ + +namespace Automattic\Jetpack\Sync; + +use WP_Error; + +/** + * A persistent queue that can be flushed in increments of N items, + * and which blocks reads until checked-out buffers are checked in or + * closed. This uses raw SQL for two reasons: speed, and not triggering + * tons of added_option callbacks. + */ +class Queue { + /** + * The queue id. + * + * @var string + */ + public $id; + /** + * Keeps track of the rows. + * + * @var int + */ + private $row_iterator; + + /** + * Queue constructor. + * + * @param string $id Name of the queue. + */ + public function __construct( $id ) { + $this->id = str_replace( '-', '_', $id ); // Necessary to ensure we don't have ID collisions in the SQL. + $this->row_iterator = 0; + $this->random_int = wp_rand( 1, 1000000 ); + } + + /** + * Add a single item to the queue. + * + * @param object $item Event object to add to queue. + */ + public function add( $item ) { + global $wpdb; + $added = false; + + // If empty, don't add. + if ( empty( $item ) ) { + return; + } + + // Attempt to serialize data, if an exception (closures) return early. + try { + $item = serialize( $item ); // phpcs:ignore WordPress.PHP.DiscouragedPHPFunctions.serialize_serialize + } catch ( \Exception $ex ) { + return; + } + + // This basically tries to add the option until enough time has elapsed that + // it has a unique (microtime-based) option key. + while ( ! $added ) { + $rows_added = $wpdb->query( + $wpdb->prepare( + "INSERT INTO $wpdb->options (option_name, option_value, autoload) VALUES (%s, %s,%s)", + $this->get_next_data_row_option_name(), + $item, + 'no' + ) + ); + $added = ( 0 !== $rows_added ); + } + } + + /** + * Insert all the items in a single SQL query. May be subject to query size limits! + * + * @param array $items Array of events to add to the queue. + * + * @return bool|\WP_Error + */ + public function add_all( $items ) { + global $wpdb; + $base_option_name = $this->get_next_data_row_option_name(); + + $query = "INSERT INTO $wpdb->options (option_name, option_value, autoload) VALUES "; + + $rows = array(); + $count_items = count( $items ); + for ( $i = 0; $i < $count_items; ++$i ) { + // skip empty items. + if ( empty( $items[ $i ] ) ) { + continue; + } + try { + $option_name = esc_sql( $base_option_name . '-' . $i ); + $option_value = esc_sql( serialize( $items[ $i ] ) ); // phpcs:ignore WordPress.PHP.DiscouragedPHPFunctions.serialize_serialize + $rows[] = "('$option_name', '$option_value', 'no')"; + } catch ( \Exception $e ) { + // Item cannot be serialized so skip. + continue; + } + } + + $rows_added = $wpdb->query( $query . join( ',', $rows ) ); // phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared + + if ( count( $items ) !== $rows_added ) { + return new WP_Error( 'row_count_mismatch', "The number of rows inserted didn't match the size of the input array" ); + } + return true; + } + + /** + * Get the front-most item on the queue without checking it out. + * + * @param int $count Number of items to return when looking at the items. + * + * @return array + */ + public function peek( $count = 1 ) { + $items = $this->fetch_items( $count ); + if ( $items ) { + return Utils::get_item_values( $items ); + } + + return array(); + } + + /** + * Gets items with particular IDs. + * + * @param array $item_ids Array of item IDs to retrieve. + * + * @return array + */ + public function peek_by_id( $item_ids ) { + $items = $this->fetch_items_by_id( $item_ids ); + if ( $items ) { + return Utils::get_item_values( $items ); + } + + return array(); + } + + /** + * Gets the queue lag. + * Lag is the difference in time between the age of the oldest item + * (aka first or frontmost item) and the current time. + * + * @param microtime $now The current time in microtime. + * + * @return float|int|mixed|null + */ + public function lag( $now = null ) { + global $wpdb; + + $first_item_name = $wpdb->get_var( + $wpdb->prepare( + "SELECT option_name FROM $wpdb->options WHERE option_name LIKE %s ORDER BY option_name ASC LIMIT 1", + "jpsq_{$this->id}-%" + ) + ); + + if ( ! $first_item_name ) { + return 0; + } + + if ( null === $now ) { + $now = microtime( true ); + } + + // Break apart the item name to get the timestamp. + $matches = null; + if ( preg_match( '/^jpsq_' . $this->id . '-(\d+\.\d+)-/', $first_item_name, $matches ) ) { + return $now - (float) $matches[1]; + } else { + return 0; + } + } + + /** + * Resets the queue. + */ + public function reset() { + global $wpdb; + $this->delete_checkout_id(); + $wpdb->query( + $wpdb->prepare( + "DELETE FROM $wpdb->options WHERE option_name LIKE %s", + "jpsq_{$this->id}-%" + ) + ); + } + + /** + * Return the size of the queue. + * + * @return int + */ + public function size() { + global $wpdb; + + return (int) $wpdb->get_var( + $wpdb->prepare( + "SELECT count(*) FROM $wpdb->options WHERE option_name LIKE %s", + "jpsq_{$this->id}-%" + ) + ); + } + + /** + * Lets you know if there is any items in the queue. + * + * We use this peculiar implementation because it's much faster than count(*). + * + * @return bool + */ + public function has_any_items() { + global $wpdb; + $value = $wpdb->get_var( + $wpdb->prepare( + "SELECT exists( SELECT option_name FROM $wpdb->options WHERE option_name LIKE %s )", + "jpsq_{$this->id}-%" + ) + ); + + return ( '1' === $value ); + } + + /** + * Used to checkout the queue. + * + * @param int $buffer_size Size of the buffer to checkout. + * + * @return Automattic\Jetpack\Sync\Queue_Buffer|bool|int|\WP_Error + */ + public function checkout( $buffer_size ) { + if ( $this->get_checkout_id() ) { + return new WP_Error( 'unclosed_buffer', 'There is an unclosed buffer' ); + } + + $buffer_id = uniqid(); + + $result = $this->set_checkout_id( $buffer_id ); + + if ( ! $result || is_wp_error( $result ) ) { + return $result; + } + + $items = $this->fetch_items( $buffer_size ); + + if ( count( $items ) === 0 ) { + return false; + } + + $buffer = new Queue_Buffer( $buffer_id, array_slice( $items, 0, $buffer_size ) ); + + return $buffer; + } + + /** + * Given a list of items return the items ids. + * + * @param array $items List of item objects. + * + * @return array Ids of the items. + */ + public function get_ids( $items ) { + return array_map( + function ( $item ) { + return $item->id; + }, + $items + ); + } + + /** + * Pop elements from the queue. + * + * @param int $limit Number of items to pop from the queue. + * + * @return array|object|null + */ + public function pop( $limit ) { + $items = $this->fetch_items( $limit ); + + $ids = $this->get_ids( $items ); + + $this->delete( $ids ); + + return $items; + } + + /** + * Get the items from the queue with a memory limit. + * + * This checks out rows until it either empties the queue or hits a certain memory limit + * it loads the sizes from the DB first so that it doesn't accidentally + * load more data into memory than it needs to. + * The only way it will load more items than $max_size is if a single queue item + * exceeds the memory limit, but in that case it will send that item by itself. + * + * @param int $max_memory (bytes) Maximum memory threshold. + * @param int $max_buffer_size Maximum buffer size (number of items). + * + * @return Automattic\Jetpack\Sync\Queue_Buffer|bool|int|\WP_Error + */ + public function checkout_with_memory_limit( $max_memory, $max_buffer_size = 500 ) { + if ( $this->get_checkout_id() ) { + return new WP_Error( 'unclosed_buffer', 'There is an unclosed buffer' ); + } + + $buffer_id = uniqid(); + + $result = $this->set_checkout_id( $buffer_id ); + + if ( ! $result || is_wp_error( $result ) ) { + return $result; + } + + // Get the map of buffer_id -> memory_size. + global $wpdb; + + $items_with_size = $wpdb->get_results( + $wpdb->prepare( + "SELECT option_name AS id, LENGTH(option_value) AS value_size FROM $wpdb->options WHERE option_name LIKE %s ORDER BY option_name ASC LIMIT %d", + "jpsq_{$this->id}-%", + $max_buffer_size + ), + OBJECT + ); + + if ( count( $items_with_size ) === 0 ) { + return false; + } + + $total_memory = 0; + $max_item_id = $items_with_size[0]->id; + $min_item_id = $max_item_id; + + foreach ( $items_with_size as $id => $item_with_size ) { + $total_memory += $item_with_size->value_size; + + // If this is the first item and it exceeds memory, allow loop to continue + // we will exit on the next iteration instead. + if ( $total_memory > $max_memory && $id > 0 ) { + break; + } + + $max_item_id = $item_with_size->id; + } + + $query = $wpdb->prepare( + "SELECT option_name AS id, option_value AS value FROM $wpdb->options WHERE option_name >= %s and option_name <= %s ORDER BY option_name ASC", + $min_item_id, + $max_item_id + ); + + $items = $wpdb->get_results( $query, OBJECT ); // phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared + foreach ( $items as $item ) { + // @codingStandardsIgnoreStart + $item->value = @unserialize( $item->value ); + // @codingStandardsIgnoreEnd + } + + if ( count( $items ) === 0 ) { + $this->delete_checkout_id(); + + return false; + } + + $buffer = new Queue_Buffer( $buffer_id, $items ); + + return $buffer; + } + + /** + * Check in the queue. + * + * @param Automattic\Jetpack\Sync\Queue_Buffer $buffer Queue_Buffer object. + * + * @return bool|\WP_Error + */ + public function checkin( $buffer ) { + $is_valid = $this->validate_checkout( $buffer ); + + if ( is_wp_error( $is_valid ) ) { + return $is_valid; + } + + $this->delete_checkout_id(); + + return true; + } + + /** + * Close the buffer. + * + * @param Automattic\Jetpack\Sync\Queue_Buffer $buffer Queue_Buffer object. + * @param null|array $ids_to_remove Ids to remove from the queue. + * + * @return bool|\WP_Error + */ + public function close( $buffer, $ids_to_remove = null ) { + $is_valid = $this->validate_checkout( $buffer ); + + if ( is_wp_error( $is_valid ) ) { + // Always delete ids_to_remove even when buffer is no longer checked-out. + // They were processed by WP.com so safe to remove from queue. + if ( ! is_null( $ids_to_remove ) ) { + $this->delete( $ids_to_remove ); + } + return $is_valid; + } + + $this->delete_checkout_id(); + + // By default clear all items in the buffer. + if ( is_null( $ids_to_remove ) ) { + $ids_to_remove = $buffer->get_item_ids(); + } + + $this->delete( $ids_to_remove ); + + return true; + } + + /** + * Delete elements from the queue. + * + * @param array $ids Ids to delete. + * + * @return bool|int + */ + private function delete( $ids ) { + if ( 0 === count( $ids ) ) { + return 0; + } + global $wpdb; + $sql = "DELETE FROM $wpdb->options WHERE option_name IN (" . implode( ', ', array_fill( 0, count( $ids ), '%s' ) ) . ')'; + $query = call_user_func_array( array( $wpdb, 'prepare' ), array_merge( array( $sql ), $ids ) ); + + return $wpdb->query( $query ); // phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared + } + + /** + * Flushes all items from the queue. + * + * @return array + */ + public function flush_all() { + $items = Utils::get_item_values( $this->fetch_items() ); + $this->reset(); + + return $items; + } + + /** + * Get all the items from the queue. + * + * @return array|object|null + */ + public function get_all() { + return $this->fetch_items(); + } + + /** + * Forces Checkin of the queue. + * Use with caution, this could allow multiple processes to delete + * and send from the queue at the same time + */ + public function force_checkin() { + $this->delete_checkout_id(); + } + + /** + * Locks checkouts from the queue + * tries to wait up to $timeout seconds for the queue to be empty. + * + * @param int $timeout The wait time in seconds for the queue to be empty. + * + * @return bool|int|\WP_Error + */ + public function lock( $timeout = 30 ) { + $tries = 0; + + while ( $this->has_any_items() && $tries < $timeout ) { + sleep( 1 ); + ++$tries; + } + + if ( 30 === $tries ) { + return new WP_Error( 'lock_timeout', 'Timeout waiting for sync queue to empty' ); + } + + if ( $this->get_checkout_id() ) { + return new WP_Error( 'unclosed_buffer', 'There is an unclosed buffer' ); + } + + // Hopefully this means we can acquire a checkout? + $result = $this->set_checkout_id( 'lock' ); + + if ( ! $result || is_wp_error( $result ) ) { + return $result; + } + + return true; + } + + /** + * Unlocks the queue. + * + * @return bool|int + */ + public function unlock() { + return $this->delete_checkout_id(); + } + + /** + * This option is specifically chosen to, as much as possible, preserve time order + * and minimise the possibility of collisions between multiple processes working + * at the same time. + * + * @return string + */ + protected function generate_option_name_timestamp() { + return sprintf( '%.6f', microtime( true ) ); + } + + /** + * Gets the checkout ID. + * + * @return bool|string + */ + private function get_checkout_id() { + global $wpdb; + $checkout_value = $wpdb->get_var( + $wpdb->prepare( + "SELECT option_value FROM $wpdb->options WHERE option_name = %s", + $this->get_lock_option_name() + ) + ); + + if ( $checkout_value ) { + list( $checkout_id, $timestamp ) = explode( ':', $checkout_value ); + if ( (int) $timestamp > time() ) { + return $checkout_id; + } + } + + return false; + } + + /** + * Sets the checkout id. + * + * @param string $checkout_id The ID of the checkout. + * + * @return bool|int + */ + private function set_checkout_id( $checkout_id ) { + global $wpdb; + + $expires = time() + Defaults::$default_sync_queue_lock_timeout; + $updated_num = $wpdb->query( + $wpdb->prepare( + "UPDATE $wpdb->options SET option_value = %s WHERE option_name = %s", + "$checkout_id:$expires", + $this->get_lock_option_name() + ) + ); + + if ( ! $updated_num ) { + $updated_num = $wpdb->query( + $wpdb->prepare( + "INSERT INTO $wpdb->options ( option_name, option_value, autoload ) VALUES ( %s, %s, 'no' )", + $this->get_lock_option_name(), + "$checkout_id:$expires" + ) + ); + } + + return $updated_num; + } + + /** + * Deletes the checkout ID. + * + * @return bool|int + */ + private function delete_checkout_id() { + global $wpdb; + // Rather than delete, which causes fragmentation, we update in place. + return $wpdb->query( + $wpdb->prepare( + "UPDATE $wpdb->options SET option_value = %s WHERE option_name = %s", + '0:0', + $this->get_lock_option_name() + ) + ); + + } + + /** + * Return the lock option name. + * + * @return string + */ + private function get_lock_option_name() { + return "jpsq_{$this->id}_checkout"; + } + + /** + * Return the next data row option name. + * + * @return string + */ + private function get_next_data_row_option_name() { + $timestamp = $this->generate_option_name_timestamp(); + + // Row iterator is used to avoid collisions where we're writing data waaay fast in a single process. + if ( PHP_INT_MAX === $this->row_iterator ) { + $this->row_iterator = 0; + } else { + $this->row_iterator += 1; + } + + return 'jpsq_' . $this->id . '-' . $timestamp . '-' . $this->random_int . '-' . $this->row_iterator; + } + + /** + * Return the items in the queue. + * + * @param null|int $limit Limit to the number of items we fetch at once. + * + * @return array|object|null + */ + private function fetch_items( $limit = null ) { + global $wpdb; + + if ( $limit ) { + $items = $wpdb->get_results( + $wpdb->prepare( + "SELECT option_name AS id, option_value AS value FROM $wpdb->options WHERE option_name LIKE %s ORDER BY option_name ASC LIMIT %d", + "jpsq_{$this->id}-%", + $limit + ), + OBJECT + ); + } else { + $items = $wpdb->get_results( + $wpdb->prepare( + "SELECT option_name AS id, option_value AS value FROM $wpdb->options WHERE option_name LIKE %s ORDER BY option_name ASC", + "jpsq_{$this->id}-%" + ), + OBJECT + ); + } + + return $this->unserialize_values( $items ); + + } + + /** + * Return items with specific ids. + * + * @param array $items_ids Array of event ids. + * + * @return array|object|null + */ + private function fetch_items_by_id( $items_ids ) { + global $wpdb; + + // return early if $items_ids is empty or not an array. + if ( empty( $items_ids ) || ! is_array( $items_ids ) ) { + return null; + } + + $ids_placeholders = implode( ', ', array_fill( 0, count( $items_ids ), '%s' ) ); + $query_with_placeholders = "SELECT option_name AS id, option_value AS value + FROM $wpdb->options + WHERE option_name IN ( $ids_placeholders )"; + $items = $wpdb->get_results( + $wpdb->prepare( + $query_with_placeholders, // phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared + $items_ids + ), + OBJECT + ); + + return $this->unserialize_values( $items ); + } + + /** + * Unserialize item values. + * + * @param array $items Events from the Queue to be unserialized. + * + * @return mixed + */ + private function unserialize_values( $items ) { + array_walk( + $items, + function ( $item ) { + // @codingStandardsIgnoreStart + $item->value = @unserialize( $item->value ); + // @codingStandardsIgnoreEnd + } + ); + + return $items; + + } + + /** + * Return true if the buffer is still valid or an Error other wise. + * + * @param Automattic\Jetpack\Sync\Queue_Buffer $buffer The Queue_Buffer. + * + * @return bool|WP_Error + */ + private function validate_checkout( $buffer ) { + if ( ! $buffer instanceof Queue_Buffer ) { + return new WP_Error( 'not_a_buffer', 'You must checkin an instance of Automattic\\Jetpack\\Sync\\Queue_Buffer' ); + } + + $checkout_id = $this->get_checkout_id(); + + if ( ! $checkout_id ) { + return new WP_Error( 'buffer_not_checked_out', 'There are no checked out buffers' ); + } + + // TODO: change to strict comparison. + if ( $checkout_id != $buffer->id ) { // phpcs:ignore WordPress.PHP.StrictComparisons.LooseComparison + return new WP_Error( 'buffer_mismatch', 'The buffer you checked in was not checked out' ); + } + + return true; + } +} |