Files
react-native/ReactCommon/fabric/attributedstring/AttributedStringBox.h
T
Valentin Shergin 909b0fe0e7 Fabric: operator== and std::hash for AttributedStringBox
Summary:
That will allow building a custom caching table for boxed stings to cache text measurements for them in TextLayoutManager.

Changelog: [Internal] Fabric-specific internal change.

Reviewed By: sammy-SC

Differential Revision: D18950428

fbshipit-source-id: 8ceef29543dc6ed540043e32d65f3295030ae90f
2019-12-12 12:53:12 -08:00

81 lines
2.4 KiB
C++

/*
* Copyright (c) Facebook, Inc. and its affiliates.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*/
#pragma once
#include <memory>
#include <react/attributedstring/AttributedString.h>
namespace facebook {
namespace react {
/*
* Represents an object storing a shared `AttributedString` or a shared pointer
* to some opaque platform-specific object that can be used as an attributed
* string. The class serves two main purposes:
* - Represent type-erased attributed string entity (which can be
* platform-specific or platform-independent);
* - Represent a container that can be copied with constant complexity.
*/
class AttributedStringBox final {
public:
enum class Mode { Value, OpaquePointer };
/*
* Default constructor constructs an empty string.
*/
AttributedStringBox();
/*
* Custom explicit constructors.
*/
explicit AttributedStringBox(AttributedString const &value);
explicit AttributedStringBox(std::shared_ptr<void> const &opaquePointer);
/*
* Movable, Copyable, Assignable.
*/
AttributedStringBox(AttributedStringBox const &other) = default;
AttributedStringBox(AttributedStringBox &&other) noexcept = default;
AttributedStringBox &operator=(AttributedStringBox const &other) = default;
AttributedStringBox &operator=(AttributedStringBox &&other) = default;
/*
* Getters.
*/
Mode getMode() const;
AttributedString const &getValue() const;
std::shared_ptr<void> getOpaquePointer() const;
private:
Mode mode_;
std::shared_ptr<AttributedString const> value_;
std::shared_ptr<void> opaquePointer_;
};
bool operator==(AttributedStringBox const &lhs, AttributedStringBox const &rhs);
bool operator!=(AttributedStringBox const &lhs, AttributedStringBox const &rhs);
} // namespace react
} // namespace facebook
template <>
struct std::hash<facebook::react::AttributedStringBox> {
size_t operator()(
facebook::react::AttributedStringBox const &attributedStringBox) const {
switch (attributedStringBox.getMode()) {
case facebook::react::AttributedStringBox::Mode::Value:
return std::hash<facebook::react::AttributedString>()(
attributedStringBox.getValue());
case facebook::react::AttributedStringBox::Mode::OpaquePointer:
return std::hash<std::shared_ptr<void>>()(
attributedStringBox.getOpaquePointer());
}
}
};