content/common/scheduler_loop_quarantine_task_observer.h

// Copyright 2025 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_COMMON_SCHEDULER_LOOP_QUARANTINE_TASK_OBSERVER_H_
#define CONTENT_COMMON_SCHEDULER_LOOP_QUARANTINE_TASK_OBSERVER_H_

#include "base/memory/safety_checks.h"
#include "base/task/task_observer.h"
#include "content/common/content_export.h"

namespace content {
// Scheduler-Loop Quarantine is a PartitionAlloc feature to protect pointers
// on stack memory. This is a task observer to tell when stack memory is
// nearly emptied based on task scheduling.
//
// For more details on the quarantine, see
// `partition_alloc/scheduler_loop_quarantine.h`.
class CONTENT_EXPORT SchedulerLoopQuarantineTaskObserver final
    : public base::TaskObserver {
 private:
  // A task is about to start. To protect the task from Use-after-Free,
  // this forces Scheduler-Loop Quarantine to perform stack-scanning
  // when it needs to purge quarantined allocations.
  // Re-entrancy is taken care of inside `scan_policy_updater_`.
  void WillProcessTask(const base::PendingTask&, bool) final;

  // At this point, the task is finished and we can say all local variables
  // for it were destroyed. It implies there is no risk of dangling local
  // pointer, hence allowing scan-less purge (faster but less secure).
  void DidProcessTask(const base::PendingTask&) final;

  base::SchedulerLoopQuarantineScanPolicyUpdater scan_policy_updater_;
};

}  // namespace content

#endif  // CONTENT_COMMON_SCHEDULER_LOOP_QUARANTINE_TASK_OBSERVER_H_