Add locking to the node api

lib/private/files/node/node.php

@@ -356,4 +356,28 @@ class Node implements \OCP\Files\Node {
 	public function getChecksum() {
 		return;
 	}
+
+	/**
+	 * @param int $type \OCP\Lock\ILockingProvider::LOCK_SHARED or \OCP\Lock\ILockingProvider::LOCK_EXCLUSIVE
+	 * @throws \OCP\Lock\LockedException
+	 */
+	public function lock($type) {
+		$this->view->lockFile($this->path, $type);
+	}
+
+	/**
+	 * @param int $type \OCP\Lock\ILockingProvider::LOCK_SHARED or \OCP\Lock\ILockingProvider::LOCK_EXCLUSIVE
+	 * @throws \OCP\Lock\LockedException
+	 */
+	public function changeLock($type) {
+		$this->view->changeLock($this->path, $type);
+	}
+
+	/**
+	 * @param int $type \OCP\Lock\ILockingProvider::LOCK_SHARED or \OCP\Lock\ILockingProvider::LOCK_EXCLUSIVE
+	 * @throws \OCP\Lock\LockedException
+	 */
+	public function unlock($type) {
+		$this->view->unlockFile($this->path, $type);
+	}
 }

lib/public/files/node.php

@@ -225,4 +225,55 @@ interface Node extends FileInfo {
 	 * @since 6.0.0
 	 */
 	public function getName();
+
+	/**
+	 * Acquire a lock on this file or folder.
+	 *
+	 * A shared (read) lock will prevent any exclusive (write) locks from being created but any number of shared locks
+	 * can be active at the same time.
+	 * An exclusive lock will prevent any other lock from being created (both shared and exclusive).
+	 *
+	 * A locked exception will be thrown if any conflicting lock already exists
+	 *
+	 * Note that this uses mandatory locking, if you acquire an exclusive lock on a file it will block *all*
+	 * other operations for that file, even within the same php process.
+	 *
+	 * Acquiring any lock on a file will also create a shared lock on all parent folders of that file.
+	 *
+	 * Note that in most cases you won't need to manually manage the locks for any files you're working with,
+	 * any filesystem operation will automatically acquire the relevant locks for that operation.
+	 *
+	 * @param int $type \OCP\Lock\ILockingProvider::LOCK_SHARED or \OCP\Lock\ILockingProvider::LOCK_EXCLUSIVE
+	 * @throws \OCP\Lock\LockedException
+	 * @since 9.1.0
+	 */
+	public function lock($type);
+
+	/**
+	 * Check the type of an existing lock.
+	 *
+	 * A shared lock can be changed to an exclusive lock is there is exactly one shared lock on the file,
+	 * an exclusive lock can always be changed to a shared lock since there can only be one exclusive lock int he first place.
+	 *
+	 * A locked exception will be thrown when these preconditions are not met.
+	 * Note that this is also the case if no existing lock exists for the file.
+	 *
+	 * @param int $targetType \OCP\Lock\ILockingProvider::LOCK_SHARED or \OCP\Lock\ILockingProvider::LOCK_EXCLUSIVE
+	 * @throws \OCP\Lock\LockedException
+	 * @since 9.1.0
+	 */
+	public function changeLock($targetType);
+
+	/**
+	 * Release an existing lock.
+	 *
+	 * This will also free up the shared locks on any parent folder that were automatically acquired when locking the file.
+	 *
+	 * Note that this method will not give any sort of error when trying to free a lock that doesn't exist.
+	 *
+	 * @param int $type \OCP\Lock\ILockingProvider::LOCK_SHARED or \OCP\Lock\ILockingProvider::LOCK_EXCLUSIVE
+	 * @throws \OCP\Lock\LockedException
+	 * @since 9.1.0
+	 */
+	public function unlock($type);
 }