chromium/third_party/blink/renderer/platform/bindings/callback_function_base.h

// Copyright 2017 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef THIRD_PARTY_BLINK_RENDERER_PLATFORM_BINDINGS_CALLBACK_FUNCTION_BASE_H_
#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_BINDINGS_CALLBACK_FUNCTION_BASE_H_

#include "base/functional/callback.h"
#include "third_party/blink/public/common/scheduler/task_attribution_id.h"
#include "third_party/blink/renderer/platform/bindings/name_client.h"
#include "third_party/blink/renderer/platform/bindings/script_state.h"
#include "third_party/blink/renderer/platform/bindings/trace_wrapper_v8_reference.h"
#include "third_party/blink/renderer/platform/heap/garbage_collected.h"

namespace blink {
namespace scheduler {
class TaskAttributionInfo;
}

// CallbackFunctionBase is the common base class of all the callback function
// classes. Most importantly this class provides a way of type dispatching (e.g.
// overload resolutions, SFINAE technique, etc.) so that it's possible to
// distinguish callback functions from anything else. Also it provides a common
// implementation of callback functions.
//
// This base class does not provide support for task attribution, so the
// callback that require such a functionality should inherit from
// CallbackFunctionWithTaskAttributionBase class.
//
// As the signatures of callback functions vary, this class does not implement
// |Invoke| member function that performs "invoke" steps. Subclasses will
// implement it.
class PLATFORM_EXPORT CallbackFunctionBase
    : public GarbageCollected<CallbackFunctionBase>,
      public NameClient { … };

// CallbackFunctionWithTaskAttributionBase is the common base class of callback
// function that require task attribution support.
// Callbacks that require such a functionality should be defined with
// [SupportsTaskAttribution] IDL extended attribute.
class PLATFORM_EXPORT CallbackFunctionWithTaskAttributionBase
    : public CallbackFunctionBase { … };

}  // namespace blink

#endif  // THIRD_PARTY_BLINK_RENDERER_PLATFORM_BINDINGS_CALLBACK_FUNCTION_BASE_H_