/*
 * Copyright (C) 2013 Google Inc. All rights reserved.
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 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer
 *    in the documentation and/or other materials provided with the
 *    distribution.
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 *    may be used to endorse or promote products derived from this
 *    software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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 */

#ifndef Microtask_h
#define Microtask_h

#include "core/CoreExport.h"
#include "platform/WebTaskRunner.h"
#include "v8/include/v8.h"
#include "wtf/Allocator.h"
#include "wtf/Functional.h"

namespace blink {

// C++ calls into script contexts which are "owned" by blink (created in a
// process where WebKit.cpp initializes v8) must declare their type:
//
//   1. Calls into page/author script from a frame
//   2. Calls into page/author script from a worker
//   3. Calls into internal script (typically setup/teardown work)
//
// Debug-time checking of this is enforced via v8::MicrotasksScope.
//
// Calls of type (1) should generally go through ScriptController, as inspector
// instrumentation is needed. ScriptController allocates V8RecursionScope for
// you.
//
// Calls of type (2) should always stack-allocate a
// v8::MicrotasksScope(kRunMicrtoasks) in the same block as the call into
// script.
//
// Calls of type (3) should stack allocate a
// v8::MicrotasksScope(kDoNotRunMicrotasks) -- this skips work that is spec'd to
// happen at the end of the outer-most script stack frame of calls into page
// script:
// http://www.whatwg.org/specs/web-apps/current-work/#perform-a-microtask-checkpoint
class CORE_EXPORT Microtask {
  STATIC_ONLY(Microtask);

 public:
  static void performCheckpoint(v8::Isolate*);

  // TODO(jochen): Make all microtasks pass in the ScriptState they want to be
  // executed in. Until then, all microtasks have to keep track of their
  // ScriptState themselves.
  static void enqueueMicrotask(std::unique_ptr<WTF::Closure>);
};

}  // namespace blink

#endif  // Microtask_h