chromium/chrome/browser/web_applications/locks/partitioned_lock_manager.h

// Copyright 2018 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CHROME_BROWSER_WEB_APPLICATIONS_LOCKS_PARTITIONED_LOCK_MANAGER_H_
#define CHROME_BROWSER_WEB_APPLICATIONS_LOCKS_PARTITIONED_LOCK_MANAGER_H_

#include <deque>
#include <iosfwd>
#include <list>
#include <memory>
#include <set>
#include <vector>

#include "base/containers/flat_map.h"
#include "base/containers/flat_set.h"
#include "base/functional/callback.h"
#include "base/location.h"
#include "base/memory/scoped_refptr.h"
#include "base/memory/weak_ptr.h"
#include "base/sequence_checker.h"
#include "base/supports_user_data.h"
#include "base/task/sequenced_task_runner.h"
#include "chrome/browser/web_applications/locks/partitioned_lock.h"
#include "chrome/browser/web_applications/locks/partitioned_lock_id.h"

namespace base {
class Value;
}

namespace web_app {

// Used to receive and hold locks from a PartitionedLockManager. This struct
// enables the PartitionedLock objects to always live in the destination of the
// caller's choosing (as opposed to having the locks be an argument in the
// callback, where they could be owned by the task scheduler).
//
// This class must be used and destructed on the same sequence as the
// PartitionedLockManager.
struct PartitionedLockHolder : public base::SupportsUserData { … };

// Holds locks of the scopes system. Granted locks are represented by the
// |PartitionedLock| class.
//
//  Invariants for the lock management system:
// * All calls must happen from the same sequenced task runner.
// * Locks are granted in the order in which they are requested.
// * Locks held by an entity must be acquired all at once. If more locks are
//   needed (where old locks will continue to be held), then all locks must be
//   released first, and then all necessary locks acquired in one acquisition
//   call.
class PartitionedLockManager { … };

bool operator<(const PartitionedLockManager::PartitionedLockRequest& x,
               const PartitionedLockManager::PartitionedLockRequest& y);
bool operator==(const PartitionedLockManager::PartitionedLockRequest& x,
                const PartitionedLockManager::PartitionedLockRequest& y);
bool operator!=(const PartitionedLockManager::PartitionedLockRequest& x,
                const PartitionedLockManager::PartitionedLockRequest& y);

}  // namespace web_app

#endif  // CHROME_BROWSER_WEB_APPLICATIONS_LOCKS_PARTITIONED_LOCK_MANAGER_H_