1 files changed, 77 insertions, 0 deletions
diff --git a/plugins/jetpack/jetpack_vendor/automattic/jetpack-sync/src/class-lock.php b/plugins/jetpack/jetpack_vendor/automattic/jetpack-sync/src/class-lock.php
new file mode 100644
index 00000000..61b89a1c
--- /dev/null
+++ b/plugins/jetpack/jetpack_vendor/automattic/jetpack-sync/src/class-lock.php
@@ -0,0 +1,77 @@
+<?php
+/**
+ * Lock class.
+ *
+ * @package automattic/jetpack-sync
+ */
+
+namespace Automattic\Jetpack\Sync;
+
+/**
+ * Lock class
+ */
+class Lock {
+	/**
+	 * Prefix of the blog lock transient.
+	 *
+	 * @access public
+	 *
+	 * @var string
+	 */
+	const LOCK_PREFIX = 'jp_sync_lock_';
+
+	/**
+	 * Default Lifetime of the lock.
+	 * This is the expiration value as such we are setting it high to handle cases where there are
+	 * long running requests. Short expiration value leads to concurrent requests and performance issues.
+	 *
+	 * @access public
+	 *
+	 * @var int
+	 */
+	const LOCK_TRANSIENT_EXPIRY = 180; // Seconds.
+
+	/**
+	 * Attempt to lock.
+	 *
+	 * @access public
+	 *
+	 * @param string $name lock name.
+	 * @param int    $expiry lock duration in seconds.
+	 *
+	 * @return boolean True if succeeded, false otherwise.
+	 */
+	public function attempt( $name, $expiry = self::LOCK_TRANSIENT_EXPIRY ) {
+		$lock_name   = self::LOCK_PREFIX . $name;
+		$locked_time = get_option( $lock_name );
+
+		if ( $locked_time ) {
+			// If expired update to false but don't send. Send will occurr in new request to avoid race conditions.
+			if ( microtime( true ) > $locked_time ) {
+				update_option( $lock_name, false, false );
+			}
+			return false;
+		}
+
+		$locked_time = microtime( true ) + $expiry;
+		update_option( $lock_name, $locked_time, false );
+		return $locked_time;
+	}
+
+	/**
+	 * Remove the lock.
+	 *
+	 * @access public
+	 *
+	 * @param string     $name                 lock name.
+	 * @param bool|float $lock_expiration lock expiration.
+	 */
+	public function remove( $name, $lock_expiration = false ) {
+		$lock_name = self::LOCK_PREFIX . $name;
+
+		// Only remove lock if current value matches our lock.
+		if ( true === $lock_expiration || (string) get_option( $lock_name ) === (string) $lock_expiration ) {
+			update_option( $lock_name, false, false );
+		}
+	}
+}