nextcloud / server

lib/private/BackgroundJob/JobList.php

Indentation +410 added lines, -410 removed lines

@@ -26,414 +26,414 @@
 use function strlen;
 
 class JobList implements IJobList {
-	/** @var array<string, string> */
-	protected array $alreadyVisitedParallelBlocked = [];
-
-	public function __construct(
-		protected readonly IDBConnection $connection,
-		protected readonly IConfig $config,
-		protected readonly ITimeFactory $timeFactory,
-		protected readonly LoggerInterface $logger,
-		protected readonly IGenerator $generator,
-	) {
-	}
-
-	#[Override]
-	public function add(IJob|string $job, mixed $argument = null, ?int $firstCheck = null): void {
-		if ($firstCheck === null) {
-			$firstCheck = $this->timeFactory->getTime();
-		}
-
-		$class = ($job instanceof IJob) ? get_class($job) : $job;
-
-		$argumentJson = json_encode($argument);
-		if (strlen($argumentJson) > 4000) {
-			throw new \InvalidArgumentException('Background job arguments can\'t exceed 4000 characters (json encoded)');
-		}
-
-		$query = $this->connection->getQueryBuilder();
-		if (!$this->has($job, $argument)) {
-			$query->insert('jobs')
-				->values([
-					'id' => $query->createNamedParameter($this->generator->nextId()),
-					'class' => $query->createNamedParameter($class),
-					'argument' => $query->createNamedParameter($argumentJson),
-					'argument_hash' => $query->createNamedParameter(hash('sha256', $argumentJson)),
-					'last_run' => $query->createNamedParameter(0, IQueryBuilder::PARAM_INT),
-					'last_checked' => $query->createNamedParameter($firstCheck, IQueryBuilder::PARAM_INT),
-				]);
-		} else {
-			$query->update('jobs')
-				->set('reserved_at', $query->expr()->literal(0, IQueryBuilder::PARAM_INT))
-				->set('last_checked', $query->createNamedParameter($firstCheck, IQueryBuilder::PARAM_INT))
-				->set('last_run', $query->createNamedParameter(0, IQueryBuilder::PARAM_INT))
-				->where($query->expr()->eq('class', $query->createNamedParameter($class)))
-				->andWhere($query->expr()->eq('argument_hash', $query->createNamedParameter(hash('sha256', $argumentJson))));
-		}
-		$query->executeStatement();
-	}
-
-	public function scheduleAfter(string $job, int $runAfter, mixed $argument = null): void {
-		$this->add($job, $argument, $runAfter);
-	}
-
-	#[Override]
-	public function remove(IJob|string $job, mixed $argument = null): void {
-		$class = ($job instanceof IJob) ? get_class($job) : $job;
-
-		$query = $this->connection->getQueryBuilder();
-		$query->delete('jobs')
-			->where($query->expr()->eq('class', $query->createNamedParameter($class)));
-		if (!is_null($argument)) {
-			$argumentJson = json_encode($argument);
-			$query->andWhere($query->expr()->eq('argument_hash', $query->createNamedParameter(hash('sha256', $argumentJson))));
-		}
-
-		// Add galera safe delete chunking if using mysql
-		// Stops us hitting wsrep_max_ws_rows when large row counts are deleted
-		if ($this->connection->getDatabaseProvider() === IDBConnection::PLATFORM_MYSQL) {
-			// Then use chunked delete
-			$max = IQueryBuilder::MAX_ROW_DELETION;
-
-			$query->setMaxResults($max);
-
-			do {
-				$deleted = $query->executeStatement();
-			} while ($deleted === $max);
-		} else {
-			// Dont use chunked delete - let the DB handle the large row count natively
-			$query->executeStatement();
-		}
-	}
-
-	#[Override]
-	public function removeById(string $id): void {
-		$query = $this->connection->getQueryBuilder();
-		$query->delete('jobs')
-			->where($query->expr()->eq('id', $query->createNamedParameter($id, IQueryBuilder::PARAM_INT)));
-		$query->executeStatement();
-	}
-
-	#[Override]
-	public function has(IJob|string $job, mixed $argument): bool {
-		$class = ($job instanceof IJob) ? get_class($job) : $job;
-		$argument = json_encode($argument);
-
-		$query = $this->connection->getQueryBuilder();
-		$query->select('id')
-			->from('jobs')
-			->where($query->expr()->eq('class', $query->createNamedParameter($class)))
-			->andWhere($query->expr()->eq('argument_hash', $query->createNamedParameter(hash('sha256', $argument))))
-			->setMaxResults(1);
-
-		$result = $query->executeQuery();
-		$row = $result->fetch();
-		$result->closeCursor();
-
-		return (bool)$row;
-	}
-
-	#[Override]
-	public function getJobs(IJob|string|null $job, ?int $limit, int $offset): array {
-		$iterable = $this->getJobsIterator($job, $limit, $offset);
-		return (is_array($iterable))
-			? $iterable
-			: iterator_to_array($iterable);
-	}
-
-	#[Override]
-	public function getJobsIterator(IJob|string|null $job, ?int $limit, int $offset): iterable {
-		$query = $this->connection->getQueryBuilder();
-		$query->select('*')
-			->from('jobs')
-			->setMaxResults($limit)
-			->setFirstResult($offset);
-
-		if ($job !== null) {
-			$class = ($job instanceof IJob) ? get_class($job) : $job;
-			$query->where($query->expr()->eq('class', $query->createNamedParameter($class)));
-		}
-
-		$result = $query->executeQuery();
-
-		while ($row = $result->fetch()) {
-			$job = $this->buildJob($row);
-			if ($job) {
-				yield $job;
-			}
-		}
-		$result->closeCursor();
-	}
-
-	#[Override]
-	public function getNext(bool $onlyTimeSensitive = false, ?array $jobClasses = null): ?IJob {
-		$query = $this->connection->getQueryBuilder();
-		$query->select('*')
-			->from('jobs')
-			->where($query->expr()->lte('reserved_at', $query->createNamedParameter($this->timeFactory->getTime() - 12 * 3600, IQueryBuilder::PARAM_INT)))
-			->andWhere($query->expr()->lte('last_checked', $query->createNamedParameter($this->timeFactory->getTime(), IQueryBuilder::PARAM_INT)))
-			->orderBy('last_checked', 'ASC')
-			->setMaxResults(1);
-
-		if ($onlyTimeSensitive) {
-			$query->andWhere($query->expr()->eq('time_sensitive', $query->createNamedParameter(IJob::TIME_SENSITIVE, IQueryBuilder::PARAM_INT)));
-		}
-
-		if (!empty($jobClasses)) {
-			$orClasses = [];
-			foreach ($jobClasses as $jobClass) {
-				$orClasses[] = $query->expr()->eq('class', $query->createNamedParameter($jobClass, IQueryBuilder::PARAM_STR));
-			}
-			$query->andWhere($query->expr()->orX(...$orClasses));
-		}
-
-		$result = $query->executeQuery();
-		$row = $result->fetch();
-		$result->closeCursor();
-
-		if ($row) {
-			$job = $this->buildJob($row);
-
-			if ($job instanceof IParallelAwareJob && !$job->getAllowParallelRuns() && $this->hasReservedJob(get_class($job))) {
-				if (!isset($this->alreadyVisitedParallelBlocked[get_class($job)])) {
-					$this->alreadyVisitedParallelBlocked[get_class($job)] = $job->getId();
-				} elseif ($this->alreadyVisitedParallelBlocked[get_class($job)] === $job->getId()) {
-					$this->logger->info('Skipped through all jobs and revisited a IParallelAwareJob blocked job again, giving up.', ['app' => 'cron']);
-					return null;
-				}
-				$this->logger->info('Skipping ' . get_class($job) . ' job with ID ' . $job->getId() . ' because another job with the same class is already running', ['app' => 'cron']);
-
-				$update = $this->connection->getQueryBuilder();
-				$update->update('jobs')
-					->set('last_checked', $update->createNamedParameter($this->timeFactory->getTime() + 1))
-					->where($update->expr()->eq('id', $update->createParameter('jobid')));
-				$update->setParameter('jobid', $row['id']);
-				$update->executeStatement();
-
-				return $this->getNext($onlyTimeSensitive, $jobClasses);
-			}
-
-			if ($job !== null && isset($this->alreadyVisitedParallelBlocked[get_class($job)])) {
-				unset($this->alreadyVisitedParallelBlocked[get_class($job)]);
-			}
-
-			if ($job instanceof \OCP\BackgroundJob\TimedJob) {
-				$now = $this->timeFactory->getTime();
-				$nextPossibleRun = $job->getLastRun() + $job->getInterval();
-				if ($now < $nextPossibleRun) {
-					// This job is not ready for execution yet. Set timestamps to the future to avoid
-					// re-checking with every cron run.
-					// To avoid bugs that lead to jobs never executing again, the future timestamp is
-					// capped at two days.
-					$nextCheck = min($nextPossibleRun, $now + 48 * 3600);
-					$updateTimedJob = $this->connection->getQueryBuilder();
-					$updateTimedJob->update('jobs')
-						->set('last_checked', $updateTimedJob->createNamedParameter($nextCheck, IQueryBuilder::PARAM_INT))
-						->where($updateTimedJob->expr()->eq('id', $updateTimedJob->createParameter('jobid')));
-					$updateTimedJob->setParameter('jobid', $row['id']);
-					$updateTimedJob->executeStatement();
-
-					return $this->getNext($onlyTimeSensitive, $jobClasses);
-				}
-			}
-
-			$update = $this->connection->getQueryBuilder();
-			$update->update('jobs')
-				->set('reserved_at', $update->createNamedParameter($this->timeFactory->getTime()))
-				->set('last_checked', $update->createNamedParameter($this->timeFactory->getTime()))
-				->where($update->expr()->eq('id', $update->createParameter('jobid')))
-				->andWhere($update->expr()->eq('reserved_at', $update->createParameter('reserved_at')))
-				->andWhere($update->expr()->eq('last_checked', $update->createParameter('last_checked')));
-			$update->setParameter('jobid', $row['id']);
-			$update->setParameter('reserved_at', $row['reserved_at']);
-			$update->setParameter('last_checked', $row['last_checked']);
-			$count = $update->executeStatement();
-
-			if ($count === 0) {
-				// Background job already executed elsewhere, try again.
-				return $this->getNext($onlyTimeSensitive, $jobClasses);
-			}
-
-			if ($job === null) {
-				// set the last_checked to 12h in the future to not check failing jobs all over again
-				$reset = $this->connection->getQueryBuilder();
-				$reset->update('jobs')
-					->set('reserved_at', $reset->expr()->literal(0, IQueryBuilder::PARAM_INT))
-					->set('last_checked', $reset->createNamedParameter($this->timeFactory->getTime() + 12 * 3600, IQueryBuilder::PARAM_INT))
-					->where($reset->expr()->eq('id', $reset->createNamedParameter($row['id'], IQueryBuilder::PARAM_INT)));
-				$reset->executeStatement();
-
-				// Background job from disabled app, try again.
-				return $this->getNext($onlyTimeSensitive, $jobClasses);
-			}
-
-			return $job;
-		} else {
-			return null;
-		}
-	}
-
-	#[Override]
-	public function getById(string $id): ?IJob {
-		$row = $this->getDetailsById($id);
-
-		if ($row) {
-			return $this->buildJob($row);
-		}
-
-		return null;
-	}
-
-	#[Override]
-	public function getDetailsById(string $id): ?array {
-		$query = $this->connection->getQueryBuilder();
-		$query->select('*')
-			->from('jobs')
-			->where($query->expr()->eq('id', $query->createNamedParameter($id, IQueryBuilder::PARAM_INT)));
-		$result = $query->executeQuery();
-		$row = $result->fetch();
-		$result->closeCursor();
-
-		if ($row) {
-			return $row;
-		}
-
-		return null;
-	}
-
-	/**
-	 * get the job object from a row in the db
-	 *
-	 * @param array{class:class-string<IJob>, id:mixed, last_run:mixed, argument:string} $row
-	 * @return ?IJob the next job to run. Beware that this object may be a singleton and may be modified by the next call to buildJob.
-	 */
-	private function buildJob(array $row): ?IJob {
-		try {
-			try {
-				// Try to load the job as a service
-				/** @var IJob $job */
-				$job = \OCP\Server::get($row['class']);
-			} catch (ContainerExceptionInterface $e) {
-				if (class_exists($row['class'])) {
-					$class = $row['class'];
-					$job = new $class();
-				} else {
-					$this->logger->warning('failed to create instance of background job: ' . $row['class'], ['app' => 'cron', 'exception' => $e]);
-					// Remove job from disabled app or old version of an app
-					$this->removeById($row['id']);
-					return null;
-				}
-			}
-
-			if (!($job instanceof IJob)) {
-				// This most likely means an invalid job was enqueued. We can ignore it.
-				return null;
-			}
-			$job->setId($row['id']);
-			$job->setLastRun((int)$row['last_run']);
-			$job->setArgument(json_decode($row['argument'], true));
-			return $job;
-		} catch (AutoloadNotAllowedException $e) {
-			// job is from a disabled app, ignore
-			return null;
-		}
-	}
-
-	/**
-	 * set the job that was last ran
-	 */
-	public function setLastJob(IJob $job): void {
-		$this->unlockJob($job);
-		$this->config->setAppValue('backgroundjob', 'lastjob', $job->getId());
-	}
-
-	#[Override]
-	public function unlockJob(IJob $job): void {
-		$query = $this->connection->getQueryBuilder();
-		$query->update('jobs')
-			->set('reserved_at', $query->expr()->literal(0, IQueryBuilder::PARAM_INT))
-			->where($query->expr()->eq('id', $query->createNamedParameter($job->getId(), IQueryBuilder::PARAM_INT)));
-		$query->executeStatement();
-	}
-
-	#[Override]
-	public function setLastRun(IJob $job): void {
-		$query = $this->connection->getQueryBuilder();
-		$query->update('jobs')
-			->set('last_run', $query->createNamedParameter(time(), IQueryBuilder::PARAM_INT))
-			->where($query->expr()->eq('id', $query->createNamedParameter($job->getId(), IQueryBuilder::PARAM_INT)));
-
-		if ($job instanceof \OCP\BackgroundJob\TimedJob
-			&& !$job->isTimeSensitive()) {
-			$query->set('time_sensitive', $query->createNamedParameter(IJob::TIME_INSENSITIVE));
-		}
-
-		$query->executeStatement();
-	}
-
-	#[Override]
-	public function setExecutionTime(IJob $job, $timeTaken): void {
-		$query = $this->connection->getQueryBuilder();
-		$query->update('jobs')
-			->set('execution_duration', $query->createNamedParameter($timeTaken, IQueryBuilder::PARAM_INT))
-			->set('reserved_at', $query->createNamedParameter(0, IQueryBuilder::PARAM_INT))
-			->where($query->expr()->eq('id', $query->createNamedParameter($job->getId(), IQueryBuilder::PARAM_INT)));
-		$query->executeStatement();
-	}
-
-	#[Override]
-	public function resetBackgroundJob(IJob $job): void {
-		$query = $this->connection->getQueryBuilder();
-		$query->update('jobs')
-			->set('last_run', $query->createNamedParameter(0, IQueryBuilder::PARAM_INT))
-			->set('reserved_at', $query->createNamedParameter(0, IQueryBuilder::PARAM_INT))
-			->where($query->expr()->eq('id', $query->createNamedParameter($job->getId()), IQueryBuilder::PARAM_INT));
-		$query->executeStatement();
-	}
-
-	#[Override]
-	public function hasReservedJob(?string $className = null): bool {
-		$query = $this->connection->getQueryBuilder();
-		$query->select('*')
-			->from('jobs')
-			->where($query->expr()->gt('reserved_at', $query->createNamedParameter($this->timeFactory->getTime() - 6 * 3600, IQueryBuilder::PARAM_INT)))
-			->setMaxResults(1);
-
-		if ($className !== null) {
-			$query->andWhere($query->expr()->eq('class', $query->createNamedParameter($className)));
-		}
-
-		try {
-			$result = $query->executeQuery();
-			$hasReservedJobs = $result->fetch() !== false;
-			$result->closeCursor();
-			return $hasReservedJobs;
-		} catch (Exception $e) {
-			$this->logger->debug('Querying reserved jobs failed', ['exception' => $e]);
-			return false;
-		}
-	}
-
-	#[Override]
-	public function countByClass(): array {
-		$query = $this->connection->getQueryBuilder();
-		$query->select('class')
-			->selectAlias($query->func()->count('id'), 'count')
-			->from('jobs')
-			->orderBy('count')
-			->groupBy('class');
-
-		$result = $query->executeQuery();
-
-		$jobs = [];
-
-		while (($row = $result->fetch()) !== false) {
-			/**
-			 * @var array{count:int, class:class-string<IJob>} $row
-			 */
-			$jobs[] = $row;
-		}
-
-		return $jobs;
-	}
+    /** @var array<string, string> */
+    protected array $alreadyVisitedParallelBlocked = [];
+
+    public function __construct(
+        protected readonly IDBConnection $connection,
+        protected readonly IConfig $config,
+        protected readonly ITimeFactory $timeFactory,
+        protected readonly LoggerInterface $logger,
+        protected readonly IGenerator $generator,
+    ) {
+    }
+
+    #[Override]
+    public function add(IJob|string $job, mixed $argument = null, ?int $firstCheck = null): void {
+        if ($firstCheck === null) {
+            $firstCheck = $this->timeFactory->getTime();
+        }
+
+        $class = ($job instanceof IJob) ? get_class($job) : $job;
+
+        $argumentJson = json_encode($argument);
+        if (strlen($argumentJson) > 4000) {
+            throw new \InvalidArgumentException('Background job arguments can\'t exceed 4000 characters (json encoded)');
+        }
+
+        $query = $this->connection->getQueryBuilder();
+        if (!$this->has($job, $argument)) {
+            $query->insert('jobs')
+                ->values([
+                    'id' => $query->createNamedParameter($this->generator->nextId()),
+                    'class' => $query->createNamedParameter($class),
+                    'argument' => $query->createNamedParameter($argumentJson),
+                    'argument_hash' => $query->createNamedParameter(hash('sha256', $argumentJson)),
+                    'last_run' => $query->createNamedParameter(0, IQueryBuilder::PARAM_INT),
+                    'last_checked' => $query->createNamedParameter($firstCheck, IQueryBuilder::PARAM_INT),
+                ]);
+        } else {
+            $query->update('jobs')
+                ->set('reserved_at', $query->expr()->literal(0, IQueryBuilder::PARAM_INT))
+                ->set('last_checked', $query->createNamedParameter($firstCheck, IQueryBuilder::PARAM_INT))
+                ->set('last_run', $query->createNamedParameter(0, IQueryBuilder::PARAM_INT))
+                ->where($query->expr()->eq('class', $query->createNamedParameter($class)))
+                ->andWhere($query->expr()->eq('argument_hash', $query->createNamedParameter(hash('sha256', $argumentJson))));
+        }
+        $query->executeStatement();
+    }
+
+    public function scheduleAfter(string $job, int $runAfter, mixed $argument = null): void {
+        $this->add($job, $argument, $runAfter);
+    }
+
+    #[Override]
+    public function remove(IJob|string $job, mixed $argument = null): void {
+        $class = ($job instanceof IJob) ? get_class($job) : $job;
+
+        $query = $this->connection->getQueryBuilder();
+        $query->delete('jobs')
+            ->where($query->expr()->eq('class', $query->createNamedParameter($class)));
+        if (!is_null($argument)) {
+            $argumentJson = json_encode($argument);
+            $query->andWhere($query->expr()->eq('argument_hash', $query->createNamedParameter(hash('sha256', $argumentJson))));
+        }
+
+        // Add galera safe delete chunking if using mysql
+        // Stops us hitting wsrep_max_ws_rows when large row counts are deleted
+        if ($this->connection->getDatabaseProvider() === IDBConnection::PLATFORM_MYSQL) {
+            // Then use chunked delete
+            $max = IQueryBuilder::MAX_ROW_DELETION;
+
+            $query->setMaxResults($max);
+
+            do {
+                $deleted = $query->executeStatement();
+            } while ($deleted === $max);
+        } else {
+            // Dont use chunked delete - let the DB handle the large row count natively
+            $query->executeStatement();
+        }
+    }
+
+    #[Override]
+    public function removeById(string $id): void {
+        $query = $this->connection->getQueryBuilder();
+        $query->delete('jobs')
+            ->where($query->expr()->eq('id', $query->createNamedParameter($id, IQueryBuilder::PARAM_INT)));
+        $query->executeStatement();
+    }
+
+    #[Override]
+    public function has(IJob|string $job, mixed $argument): bool {
+        $class = ($job instanceof IJob) ? get_class($job) : $job;
+        $argument = json_encode($argument);
+
+        $query = $this->connection->getQueryBuilder();
+        $query->select('id')
+            ->from('jobs')
+            ->where($query->expr()->eq('class', $query->createNamedParameter($class)))
+            ->andWhere($query->expr()->eq('argument_hash', $query->createNamedParameter(hash('sha256', $argument))))
+            ->setMaxResults(1);
+
+        $result = $query->executeQuery();
+        $row = $result->fetch();
+        $result->closeCursor();
+
+        return (bool)$row;
+    }
+
+    #[Override]
+    public function getJobs(IJob|string|null $job, ?int $limit, int $offset): array {
+        $iterable = $this->getJobsIterator($job, $limit, $offset);
+        return (is_array($iterable))
+            ? $iterable
+            : iterator_to_array($iterable);
+    }
+
+    #[Override]
+    public function getJobsIterator(IJob|string|null $job, ?int $limit, int $offset): iterable {
+        $query = $this->connection->getQueryBuilder();
+        $query->select('*')
+            ->from('jobs')
+            ->setMaxResults($limit)
+            ->setFirstResult($offset);
+
+        if ($job !== null) {
+            $class = ($job instanceof IJob) ? get_class($job) : $job;
+            $query->where($query->expr()->eq('class', $query->createNamedParameter($class)));
+        }
+
+        $result = $query->executeQuery();
+
+        while ($row = $result->fetch()) {
+            $job = $this->buildJob($row);
+            if ($job) {
+                yield $job;
+            }
+        }
+        $result->closeCursor();
+    }
+
+    #[Override]
+    public function getNext(bool $onlyTimeSensitive = false, ?array $jobClasses = null): ?IJob {
+        $query = $this->connection->getQueryBuilder();
+        $query->select('*')
+            ->from('jobs')
+            ->where($query->expr()->lte('reserved_at', $query->createNamedParameter($this->timeFactory->getTime() - 12 * 3600, IQueryBuilder::PARAM_INT)))
+            ->andWhere($query->expr()->lte('last_checked', $query->createNamedParameter($this->timeFactory->getTime(), IQueryBuilder::PARAM_INT)))
+            ->orderBy('last_checked', 'ASC')
+            ->setMaxResults(1);
+
+        if ($onlyTimeSensitive) {
+            $query->andWhere($query->expr()->eq('time_sensitive', $query->createNamedParameter(IJob::TIME_SENSITIVE, IQueryBuilder::PARAM_INT)));
+        }
+
+        if (!empty($jobClasses)) {
+            $orClasses = [];
+            foreach ($jobClasses as $jobClass) {
+                $orClasses[] = $query->expr()->eq('class', $query->createNamedParameter($jobClass, IQueryBuilder::PARAM_STR));
+            }
+            $query->andWhere($query->expr()->orX(...$orClasses));
+        }
+
+        $result = $query->executeQuery();
+        $row = $result->fetch();
+        $result->closeCursor();
+
+        if ($row) {
+            $job = $this->buildJob($row);
+
+            if ($job instanceof IParallelAwareJob && !$job->getAllowParallelRuns() && $this->hasReservedJob(get_class($job))) {
+                if (!isset($this->alreadyVisitedParallelBlocked[get_class($job)])) {
+                    $this->alreadyVisitedParallelBlocked[get_class($job)] = $job->getId();
+                } elseif ($this->alreadyVisitedParallelBlocked[get_class($job)] === $job->getId()) {
+                    $this->logger->info('Skipped through all jobs and revisited a IParallelAwareJob blocked job again, giving up.', ['app' => 'cron']);
+                    return null;
+                }
+                $this->logger->info('Skipping ' . get_class($job) . ' job with ID ' . $job->getId() . ' because another job with the same class is already running', ['app' => 'cron']);
+
+                $update = $this->connection->getQueryBuilder();
+                $update->update('jobs')
+                    ->set('last_checked', $update->createNamedParameter($this->timeFactory->getTime() + 1))
+                    ->where($update->expr()->eq('id', $update->createParameter('jobid')));
+                $update->setParameter('jobid', $row['id']);
+                $update->executeStatement();
+
+                return $this->getNext($onlyTimeSensitive, $jobClasses);
+            }
+
+            if ($job !== null && isset($this->alreadyVisitedParallelBlocked[get_class($job)])) {
+                unset($this->alreadyVisitedParallelBlocked[get_class($job)]);
+            }
+
+            if ($job instanceof \OCP\BackgroundJob\TimedJob) {
+                $now = $this->timeFactory->getTime();
+                $nextPossibleRun = $job->getLastRun() + $job->getInterval();
+                if ($now < $nextPossibleRun) {
+                    // This job is not ready for execution yet. Set timestamps to the future to avoid
+                    // re-checking with every cron run.
+                    // To avoid bugs that lead to jobs never executing again, the future timestamp is
+                    // capped at two days.
+                    $nextCheck = min($nextPossibleRun, $now + 48 * 3600);
+                    $updateTimedJob = $this->connection->getQueryBuilder();
+                    $updateTimedJob->update('jobs')
+                        ->set('last_checked', $updateTimedJob->createNamedParameter($nextCheck, IQueryBuilder::PARAM_INT))
+                        ->where($updateTimedJob->expr()->eq('id', $updateTimedJob->createParameter('jobid')));
+                    $updateTimedJob->setParameter('jobid', $row['id']);
+                    $updateTimedJob->executeStatement();
+
+                    return $this->getNext($onlyTimeSensitive, $jobClasses);
+                }
+            }
+
+            $update = $this->connection->getQueryBuilder();
+            $update->update('jobs')
+                ->set('reserved_at', $update->createNamedParameter($this->timeFactory->getTime()))
+                ->set('last_checked', $update->createNamedParameter($this->timeFactory->getTime()))
+                ->where($update->expr()->eq('id', $update->createParameter('jobid')))
+                ->andWhere($update->expr()->eq('reserved_at', $update->createParameter('reserved_at')))
+                ->andWhere($update->expr()->eq('last_checked', $update->createParameter('last_checked')));
+            $update->setParameter('jobid', $row['id']);
+            $update->setParameter('reserved_at', $row['reserved_at']);
+            $update->setParameter('last_checked', $row['last_checked']);
+            $count = $update->executeStatement();
+
+            if ($count === 0) {
+                // Background job already executed elsewhere, try again.
+                return $this->getNext($onlyTimeSensitive, $jobClasses);
+            }
+
+            if ($job === null) {
+                // set the last_checked to 12h in the future to not check failing jobs all over again
+                $reset = $this->connection->getQueryBuilder();
+                $reset->update('jobs')
+                    ->set('reserved_at', $reset->expr()->literal(0, IQueryBuilder::PARAM_INT))
+                    ->set('last_checked', $reset->createNamedParameter($this->timeFactory->getTime() + 12 * 3600, IQueryBuilder::PARAM_INT))
+                    ->where($reset->expr()->eq('id', $reset->createNamedParameter($row['id'], IQueryBuilder::PARAM_INT)));
+                $reset->executeStatement();
+
+                // Background job from disabled app, try again.
+                return $this->getNext($onlyTimeSensitive, $jobClasses);
+            }
+
+            return $job;
+        } else {
+            return null;
+        }
+    }
+
+    #[Override]
+    public function getById(string $id): ?IJob {
+        $row = $this->getDetailsById($id);
+
+        if ($row) {
+            return $this->buildJob($row);
+        }
+
+        return null;
+    }
+
+    #[Override]
+    public function getDetailsById(string $id): ?array {
+        $query = $this->connection->getQueryBuilder();
+        $query->select('*')
+            ->from('jobs')
+            ->where($query->expr()->eq('id', $query->createNamedParameter($id, IQueryBuilder::PARAM_INT)));
+        $result = $query->executeQuery();
+        $row = $result->fetch();
+        $result->closeCursor();
+
+        if ($row) {
+            return $row;
+        }
+
+        return null;
+    }
+
+    /**
+     * get the job object from a row in the db
+     *
+     * @param array{class:class-string<IJob>, id:mixed, last_run:mixed, argument:string} $row
+     * @return ?IJob the next job to run. Beware that this object may be a singleton and may be modified by the next call to buildJob.
+     */
+    private function buildJob(array $row): ?IJob {
+        try {
+            try {
+                // Try to load the job as a service
+                /** @var IJob $job */
+                $job = \OCP\Server::get($row['class']);
+            } catch (ContainerExceptionInterface $e) {
+                if (class_exists($row['class'])) {
+                    $class = $row['class'];
+                    $job = new $class();
+                } else {
+                    $this->logger->warning('failed to create instance of background job: ' . $row['class'], ['app' => 'cron', 'exception' => $e]);
+                    // Remove job from disabled app or old version of an app
+                    $this->removeById($row['id']);
+                    return null;
+                }
+            }
+
+            if (!($job instanceof IJob)) {
+                // This most likely means an invalid job was enqueued. We can ignore it.
+                return null;
+            }
+            $job->setId($row['id']);
+            $job->setLastRun((int)$row['last_run']);
+            $job->setArgument(json_decode($row['argument'], true));
+            return $job;
+        } catch (AutoloadNotAllowedException $e) {
+            // job is from a disabled app, ignore
+            return null;
+        }
+    }
+
+    /**
+     * set the job that was last ran
+     */
+    public function setLastJob(IJob $job): void {
+        $this->unlockJob($job);
+        $this->config->setAppValue('backgroundjob', 'lastjob', $job->getId());
+    }
+
+    #[Override]
+    public function unlockJob(IJob $job): void {
+        $query = $this->connection->getQueryBuilder();
+        $query->update('jobs')
+            ->set('reserved_at', $query->expr()->literal(0, IQueryBuilder::PARAM_INT))
+            ->where($query->expr()->eq('id', $query->createNamedParameter($job->getId(), IQueryBuilder::PARAM_INT)));
+        $query->executeStatement();
+    }
+
+    #[Override]
+    public function setLastRun(IJob $job): void {
+        $query = $this->connection->getQueryBuilder();
+        $query->update('jobs')
+            ->set('last_run', $query->createNamedParameter(time(), IQueryBuilder::PARAM_INT))
+            ->where($query->expr()->eq('id', $query->createNamedParameter($job->getId(), IQueryBuilder::PARAM_INT)));
+
+        if ($job instanceof \OCP\BackgroundJob\TimedJob
+            && !$job->isTimeSensitive()) {
+            $query->set('time_sensitive', $query->createNamedParameter(IJob::TIME_INSENSITIVE));
+        }
+
+        $query->executeStatement();
+    }
+
+    #[Override]
+    public function setExecutionTime(IJob $job, $timeTaken): void {
+        $query = $this->connection->getQueryBuilder();
+        $query->update('jobs')
+            ->set('execution_duration', $query->createNamedParameter($timeTaken, IQueryBuilder::PARAM_INT))
+            ->set('reserved_at', $query->createNamedParameter(0, IQueryBuilder::PARAM_INT))
+            ->where($query->expr()->eq('id', $query->createNamedParameter($job->getId(), IQueryBuilder::PARAM_INT)));
+        $query->executeStatement();
+    }
+
+    #[Override]
+    public function resetBackgroundJob(IJob $job): void {
+        $query = $this->connection->getQueryBuilder();
+        $query->update('jobs')
+            ->set('last_run', $query->createNamedParameter(0, IQueryBuilder::PARAM_INT))
+            ->set('reserved_at', $query->createNamedParameter(0, IQueryBuilder::PARAM_INT))
+            ->where($query->expr()->eq('id', $query->createNamedParameter($job->getId()), IQueryBuilder::PARAM_INT));
+        $query->executeStatement();
+    }
+
+    #[Override]
+    public function hasReservedJob(?string $className = null): bool {
+        $query = $this->connection->getQueryBuilder();
+        $query->select('*')
+            ->from('jobs')
+            ->where($query->expr()->gt('reserved_at', $query->createNamedParameter($this->timeFactory->getTime() - 6 * 3600, IQueryBuilder::PARAM_INT)))
+            ->setMaxResults(1);
+
+        if ($className !== null) {
+            $query->andWhere($query->expr()->eq('class', $query->createNamedParameter($className)));
+        }
+
+        try {
+            $result = $query->executeQuery();
+            $hasReservedJobs = $result->fetch() !== false;
+            $result->closeCursor();
+            return $hasReservedJobs;
+        } catch (Exception $e) {
+            $this->logger->debug('Querying reserved jobs failed', ['exception' => $e]);
+            return false;
+        }
+    }
+
+    #[Override]
+    public function countByClass(): array {
+        $query = $this->connection->getQueryBuilder();
+        $query->select('class')
+            ->selectAlias($query->func()->count('id'), 'count')
+            ->from('jobs')
+            ->orderBy('count')
+            ->groupBy('class');
+
+        $result = $query->executeQuery();
+
+        $jobs = [];
+
+        while (($row = $result->fetch()) !== false) {
+            /**
+             * @var array{count:int, class:class-string<IJob>} $row
+             */
+            $jobs[] = $row;
+        }
+
+        return $jobs;
+    }
 }