mirror of
https://github.com/facebook/react-native.git
synced 2025-11-01 09:14:26 +00:00
Joshua Gross
7f792c8376
Summary: For better cross-platform consistency, migrate usages of NDEBUG to REACT_NATIVE_DEBUG. See flags.h for explanation. Changelog: [Internal] Reviewed By: PeteTheHeat Differential Revision: D26695162 fbshipit-source-id: 5615355f76b9c78d0f8981b3443b7c5900939ede
96 lines
2.7 KiB
C++
96 lines
2.7 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 <atomic>
|
|
|
|
#include <react/debug/flags.h>
|
|
|
|
namespace facebook {
|
|
namespace react {
|
|
|
|
/*
|
|
* Represents an object which can be *sealed* (imperatively marked as
|
|
* immutable).
|
|
*
|
|
* The `sealed` flag is tight to a particular instance of the class and resets
|
|
* to `false` for all newly created (by copy-constructor, assignment operator
|
|
* and so on) derivative objects.
|
|
*
|
|
* Why do we need this? In Fabric, some objects are semi-immutable
|
|
* even if they are explicitly marked as `const`. It means that in some special
|
|
* cases those objects can be const-casted-away and then mutated. That comes
|
|
* from the fact that we share some object's life-cycle responsibilities with
|
|
* React and the immutability is guaranteed by some logic splitted between
|
|
* native and JavaScript worlds (which makes it impossible to fully use
|
|
* immutability enforcement at a language level). To detect possible errors as
|
|
* early as possible we additionally mark objects as *sealed* after some stages
|
|
* and then enforce this at run-time.
|
|
*
|
|
* How to use:
|
|
* 1. Inherit your class from `Sealable`.
|
|
* 2. Call `ensureUnsealed()` in all cases where the object might be mutated:
|
|
* a. At the beginning of all *always* mutating `non-const` methods;
|
|
* b. Right before the place where actual mutation happens in all
|
|
* *possible* mutating `non-const` methods; c. Right after performing
|
|
* `const_cast`. (Optionally. This is not strictly necessary but might help
|
|
* detect problems earlier.)
|
|
* 3. Call `seal()` at some point from which any modifications
|
|
* must be prevented.
|
|
*/
|
|
|
|
#ifndef REACT_NATIVE_DEBUG
|
|
|
|
// Release-mode, production version
|
|
class Sealable {
|
|
public:
|
|
inline void seal() const {}
|
|
inline bool getSealed() const {
|
|
return true;
|
|
}
|
|
inline void ensureUnsealed() const {}
|
|
};
|
|
|
|
#else
|
|
|
|
// Debug version
|
|
class Sealable {
|
|
public:
|
|
Sealable();
|
|
Sealable(const Sealable &other);
|
|
Sealable(Sealable &&other) noexcept;
|
|
~Sealable() noexcept;
|
|
Sealable &operator=(const Sealable &other);
|
|
Sealable &operator=(Sealable &&other) noexcept;
|
|
|
|
/*
|
|
* Seals the object. This operation is irreversible;
|
|
* the object cannot be "unsealed" after being sealing.
|
|
*/
|
|
void seal() const;
|
|
|
|
/*
|
|
* Returns if the object already sealed or not.
|
|
*/
|
|
bool getSealed() const;
|
|
|
|
/*
|
|
* Throws an exception if the object is sealed.
|
|
* Call this from all non-`const` methods.
|
|
*/
|
|
void ensureUnsealed() const;
|
|
|
|
private:
|
|
mutable std::atomic<bool> sealed_{false};
|
|
};
|
|
|
|
#endif
|
|
|
|
} // namespace react
|
|
} // namespace facebook
|