gecko-dev/layout/style/ServoComputedData.h

117 строки
3.5 KiB
C++

/* -*- 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/. */
#ifndef mozilla_ServoComputedData_h
#define mozilla_ServoComputedData_h
class nsWindowSizes;
/*
* ServoComputedData and its related types.
*/
#define STYLE_STRUCT(name_) struct nsStyle##name_;
#include "nsStyleStructList.h"
#undef STYLE_STRUCT
namespace mozilla {
template <typename T>
struct ServoRawOffsetArc {
// This is a pointer to a T that lives inside a servo_arc::Arc<T>, and
// which already has had its reference count incremented.
T* mPtr;
};
struct ServoWritingMode {
uint8_t mBits;
};
struct ServoCustomPropertiesMap {
uintptr_t mPtr;
};
struct ServoRuleNode {
uintptr_t mPtr;
};
class ComputedStyle;
struct ServoVisitedStyle {
// This is actually a strong reference but ServoComputedData's
// destructor is managed by the Rust code so we just use a regular
// pointer
ComputedStyle* mPtr;
};
struct ServoComputedValueFlags {
uint16_t mFlags;
};
#define STYLE_STRUCT(name_) struct Gecko##name_;
#include "nsStyleStructList.h"
#undef STYLE_STRUCT
} // namespace mozilla
class ServoComputedData;
struct ServoComputedDataForgotten {
// Make sure you manually mem::forget the backing ServoComputedData
// after calling this
explicit ServoComputedDataForgotten(const ServoComputedData* aValue)
: mPtr(aValue) {}
const ServoComputedData* mPtr;
};
/**
* We want C++ to be able to read the style struct fields of ComputedValues
* so we define this type on the C++ side and use the bindgenned version
* on the Rust side.
*/
class ServoComputedData {
friend class mozilla::ComputedStyle;
public:
// Constructs via memcpy. Will not move out of aValue.
explicit ServoComputedData(const ServoComputedDataForgotten aValue);
#define STYLE_STRUCT(name_) \
mozilla::ServoRawOffsetArc<mozilla::Gecko##name_> name_; \
inline const nsStyle##name_* GetStyle##name_() const;
#include "nsStyleStructList.h"
#undef STYLE_STRUCT
void AddSizeOfExcludingThis(nsWindowSizes& aSizes) const;
private:
mozilla::ServoCustomPropertiesMap custom_properties;
mozilla::ServoWritingMode writing_mode;
mozilla::ServoComputedValueFlags flags;
/// The rule node representing the ordered list of rules matched for this
/// node. Can be None for default values and text nodes. This is
/// essentially an optimization to avoid referencing the root rule node.
mozilla::ServoRuleNode rules;
/// The element's computed values if visited, only computed if there's a
/// relevant link for this element. A element's "relevant link" is the
/// element being matched if it is a link or the nearest ancestor link.
mozilla::ServoVisitedStyle visited_style;
// C++ just sees this struct as a bucket of bits, and will
// do the wrong thing if we let it use the default copy ctor/assignment
// operator. Remove them so that there is no footgun.
//
// We remove the move ctor/assignment operator as well, because
// moves in C++ don't prevent destructors from being called,
// which will lead to double frees.
ServoComputedData& operator=(const ServoComputedData&) = delete;
ServoComputedData(const ServoComputedData&) = delete;
ServoComputedData&& operator=(const ServoComputedData&&) = delete;
ServoComputedData(const ServoComputedData&&) = delete;
};
#endif // mozilla_ServoComputedData_h