microtask.h

// Copyright 2018 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_MICROTASK_H_
#define V8_OBJECTS_MICROTASK_H_

#include "src/objects.h"
#include "src/objects/struct.h"

// Has to be the last include (doesn't have include guards):
#include "src/objects/object-macros.h"

namespace v8 {
namespace internal {

// Abstract base class for all microtasks that can be scheduled on the
// microtask queue. This class merely serves the purpose of a marker
// interface.
class Microtask : public Struct {
 public:
  // Dispatched behavior.
  DECL_CAST(Microtask)
  DECL_VERIFIER(Microtask)

  OBJECT_CONSTRUCTORS(Microtask, Struct);
};

// A CallbackTask is a special Microtask that allows us to schedule
// C++ microtask callbacks on the microtask queue. This is heavily
// used by Blink for example.
class CallbackTask : public Microtask {
 public:
  DECL_ACCESSORS(callback, Foreign)
  DECL_ACCESSORS(data, Foreign)

// Layout description.
#define CALLBACK_TASK_FIELDS(V)   \
  V(kCallbackOffset, kTaggedSize) \
  V(kDataOffset, kTaggedSize)     \
  /* Total size. */               \
  V(kSize, 0)

  DEFINE_FIELD_OFFSET_CONSTANTS(Microtask::kHeaderSize, CALLBACK_TASK_FIELDS)
#undef CALLBACK_TASK_FIELDS

  // Dispatched behavior.
  DECL_CAST(CallbackTask)
  DECL_PRINTER(CallbackTask)
  DECL_VERIFIER(CallbackTask)

  OBJECT_CONSTRUCTORS(CallbackTask, Microtask);
};

// A CallableTask is a special (internal) Microtask that allows us to
// schedule arbitrary callables on the microtask queue. We use this
// for various tests of the microtask queue.
class CallableTask : public Microtask {
 public:
  DECL_ACCESSORS(callable, JSReceiver)
  DECL_ACCESSORS(context, Context)

// Layout description.
#define CALLABLE_TASK_FIELDS(V)   \
  V(kCallableOffset, kTaggedSize) \
  V(kContextOffset, kTaggedSize)  \
  /* Total size. */               \
  V(kSize, 0)

  DEFINE_FIELD_OFFSET_CONSTANTS(Microtask::kHeaderSize, CALLABLE_TASK_FIELDS)
#undef CALLABLE_TASK_FIELDS

  // Dispatched behavior.
  DECL_CAST(CallableTask)
  DECL_PRINTER(CallableTask)
  DECL_VERIFIER(CallableTask)
  void BriefPrintDetails(std::ostream& os);

  OBJECT_CONSTRUCTORS(CallableTask, Microtask);
};

}  // namespace internal
}  // namespace v8

#include "src/objects/object-macros-undef.h"

#endif  // V8_OBJECTS_MICROTASK_H_