gecko-dev/layout/style/ServoUtils.h

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/* -*- 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
# define MOZ_DECL_STYLO_CHECK_METHODS \
bool IsGecko() const { return false; } \
bool IsServo() const { return true; }
#define MOZ_DECL_STYLO_CONVERT_METHODS_SERVO(servotype_) \
inline servotype_* AsServo(); \
inline const servotype_* AsServo() const; \
inline servotype_* GetAsServo(); \
inline const servotype_* GetAsServo() const;
#define MOZ_DECL_STYLO_CONVERT_METHODS_GECKO(geckotype_) \
inline geckotype_* AsGecko(); \
inline const geckotype_* AsGecko() const; \
inline geckotype_* GetAsGecko(); \
inline const geckotype_* GetAsGecko() const;
#define MOZ_DECL_STYLO_CONVERT_METHODS(geckotype_, servotype_) \
MOZ_DECL_STYLO_CONVERT_METHODS_SERVO(servotype_)
/**
* Macro used in a base class of |geckotype_| and |servotype_|.
* The class should define |StyleBackendType mType;| itself.
*/
#define MOZ_DECL_STYLO_METHODS(geckotype_, servotype_) \
MOZ_DECL_STYLO_CHECK_METHODS \
MOZ_DECL_STYLO_CONVERT_METHODS(geckotype_, servotype_)
#define MOZ_DEFINE_STYLO_METHODS_GECKO(type_, geckotype_) \
geckotype_* type_::AsGecko() { \
MOZ_ASSERT(IsGecko()); \
return static_cast<geckotype_*>(this); \
} \
const geckotype_* type_::AsGecko() const { \
MOZ_ASSERT(IsGecko()); \
return static_cast<const geckotype_*>(this); \
} \
geckotype_* type_::GetAsGecko() { \
return IsGecko() ? AsGecko() : nullptr; \
} \
const geckotype_* type_::GetAsGecko() const { \
return IsGecko() ? AsGecko() : nullptr; \
}
#define MOZ_DEFINE_STYLO_METHODS_SERVO(type_, servotype_) \
servotype_* type_::AsServo() { \
MOZ_ASSERT(IsServo()); \
return static_cast<servotype_*>(this); \
} \
const servotype_* type_::AsServo() const { \
MOZ_ASSERT(IsServo()); \
return static_cast<const servotype_*>(this); \
} \
servotype_* type_::GetAsServo() { \
return IsServo() ? AsServo() : nullptr; \
} \
const servotype_* type_::GetAsServo() const { \
return IsServo() ? AsServo() : nullptr; \
}
/**
* Macro used in inline header of class |type_| with its Gecko and Servo
* subclasses named |geckotype_| and |servotype_| correspondingly for
* implementing the inline methods defined by MOZ_DECL_STYLO_METHODS.
*/
#define MOZ_DEFINE_STYLO_METHODS(type_, geckotype_, servotype_) \
MOZ_DEFINE_STYLO_METHODS_SERVO(type_, servotype_)
#define MOZ_STYLO_THIS_TYPE mozilla::RemovePointer<decltype(this)>::Type
#define MOZ_STYLO_GECKO_TYPE mozilla::RemovePointer<decltype(AsGecko())>::Type
#define MOZ_STYLO_SERVO_TYPE mozilla::RemovePointer<decltype(AsServo())>::Type
/**
* Macro used to forward a method call to the concrete method defined by
* the Servo or Gecko implementation. The class of the method using it
* should use MOZ_DECL_STYLO_METHODS to define basic stylo methods.
*/
#define MOZ_STYLO_FORWARD_CONCRETE(method_, geckoargs_, servoargs_) \
return AsServo()->method_ servoargs_;
#define MOZ_STYLO_FORWARD(method_, args_) \
MOZ_STYLO_FORWARD_CONCRETE(method_, args_, args_)
#endif // mozilla_ServoUtils_h