Your IP : 3.139.67.5
<?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 ( $ids_to_remove !== null ) {
$this->delete( $ids_to_remove );
}
return $is_valid;
}
$this->delete_checkout_id();
// By default clear all items in the buffer.
if ( $ids_to_remove === null ) {
$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();
}
/**
* Checks if the queue is locked.
*
* @return bool
*/
public function is_locked() {
return (bool) $this->get_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 Universal.Operators.StrictComparisons.LooseNotEqual
return new WP_Error( 'buffer_mismatch', 'The buffer you checked in was not checked out' );
}
return true;
}
}