chromium/v8/src/objects/waiter-queue-node.h

// Copyright 2024 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef V8_OBJECTS_WAITER_QUEUE_NODE_H_
#define V8_OBJECTS_WAITER_QUEUE_NODE_H_

#include "src/base/platform/condition-variable.h"
#include "src/base/platform/mutex.h"

namespace v8 {

namespace base {
class TimeDelta;
}  // namespace base

namespace internal {

class Context;
class Isolate;
template <typename T>
class Tagged;

namespace detail {

// To manage waiting threads inside JSSynchronizationPrimitives, there is a
// process-wide doubly-linked intrusive list per waiter (i.e. mutex or condition
// variable). There is a per-thread node allocated on the stack when the thread
// goes to sleep for synchronous locking and waiting, and a per-call node
// allocated on the C++ heap for asynchronous locking and waiting.
//
// When compressing pointers (including when sandboxing), the access to the
// node is indirected through the shared external pointer table.
//
// The WaiterQueueNode is an abstract class encapsulting the general queue
// logic (enqueue, dequeue, etc...). Its extensions add the logic to handle
// notifications and sync/async waiting.
// TODO(v8:12547): Unittest this.
class V8_NODISCARD WaiterQueueNode { … };

}  // namespace detail
}  // namespace internal
}  // namespace v8

#endif  // V8_OBJECTS_WAITER_QUEUE_NODE_H_