/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* vim: set ts=8 sts=2 et sw=2 tw=80: */

/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/* some utilities for stylo */

#ifndef mozilla_ServoUtils_h

#define mozilla_ServoUtils_h

#include "mozilla/Assertions.h"

#include "mozilla/TypeTraits.h"

#include "MainThreadUtils.h"

namespace mozilla {

// Defined in ServoBindings.cpp.

void AssertIsMainThreadOrServoFontMetricsLocked();

class ServoStyleSet;

extern ServoStyleSet* sInServoTraversal;

inline bool IsInServoTraversal()

{

  // The callers of this function are generally main-thread-only _except_

  // for potentially running during the Servo traversal, in which case they may

  // take special paths that avoid writing to caches and the like. In order

  // to allow those callers to branch efficiently without checking TLS, we

  // maintain this static boolean. However, the danger is that those callers

  // are generally unprepared to deal with non-Servo-but-also-non-main-thread

  // callers, and are likely to take the main-thread codepath if this function

  // returns false. So we assert against other non-main-thread callers here.

  MOZ_ASSERT(sInServoTraversal || NS_IsMainThread());

  return sInServoTraversal;

}

} // namespace mozilla

#endif // mozilla_ServoUtils_h