1 files changed, 101 insertions, 0 deletions
diff --git a/lib/private/Files/Lock/LockManager.php b/lib/private/Files/Lock/LockManager.php
new file mode 100644
index 00000000000..978c378e506
--- /dev/null
+++ b/lib/private/Files/Lock/LockManager.php
@@ -0,0 +1,101 @@
+<?php
+
+/**
+ * SPDX-FileCopyrightText: 2022 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OC\Files\Lock;
+
+use OCP\Files\Lock\ILock;
+use OCP\Files\Lock\ILockManager;
+use OCP\Files\Lock\ILockProvider;
+use OCP\Files\Lock\LockContext;
+use OCP\PreConditionNotMetException;
+use Psr\Container\ContainerExceptionInterface;
+use Psr\Container\NotFoundExceptionInterface;
+
+class LockManager implements ILockManager {
+	private ?string $lockProviderClass = null;
+	private ?ILockProvider $lockProvider = null;
+	private ?LockContext $lockInScope = null;
+
+	public function registerLockProvider(ILockProvider $lockProvider): void {
+		if ($this->lockProvider) {
+			throw new PreConditionNotMetException('There is already a registered lock provider');
+		}
+
+		$this->lockProvider = $lockProvider;
+	}
+
+	public function registerLazyLockProvider(string $lockProviderClass): void {
+		if ($this->lockProviderClass || $this->lockProvider) {
+			throw new PreConditionNotMetException('There is already a registered lock provider');
+		}
+
+		$this->lockProviderClass = $lockProviderClass;
+	}
+
+	private function getLockProvider(): ?ILockProvider {
+		if ($this->lockProvider) {
+			return $this->lockProvider;
+		}
+		if ($this->lockProviderClass) {
+			try {
+				$this->lockProvider = \OCP\Server::get($this->lockProviderClass);
+			} catch (NotFoundExceptionInterface|ContainerExceptionInterface $e) {
+			}
+		}
+
+		return $this->lockProvider;
+	}
+
+	public function isLockProviderAvailable(): bool {
+		return $this->getLockProvider() !== null;
+	}
+
+	public function runInScope(LockContext $lock, callable $callback): void {
+		if (!$this->getLockProvider()) {
+			$callback();
+			return;
+		}
+
+		if ($this->lockInScope) {
+			throw new PreConditionNotMetException('Could not obtain lock scope as already in use by ' . $this->lockInScope);
+		}
+
+		try {
+			$this->lockInScope = $lock;
+			$callback();
+		} finally {
+			$this->lockInScope = null;
+		}
+	}
+
+	public function getLockInScope(): ?LockContext {
+		return $this->lockInScope;
+	}
+
+	public function getLocks(int $fileId): array {
+		if (!$this->getLockProvider()) {
+			throw new PreConditionNotMetException('No lock provider available');
+		}
+
+		return $this->getLockProvider()->getLocks($fileId);
+	}
+
+	public function lock(LockContext $lockInfo): ILock {
+		if (!$this->getLockProvider()) {
+			throw new PreConditionNotMetException('No lock provider available');
+		}
+
+		return $this->getLockProvider()->lock($lockInfo);
+	}
+
+	public function unlock(LockContext $lockInfo): void {
+		if (!$this->getLockProvider()) {
+			throw new PreConditionNotMetException('No lock provider available');
+		}
+
+		$this->getLockProvider()->unlock($lockInfo);
+	}
+}