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802534e611
Summary: In React Native there are several use cases where React State is not the only input that affects the component tree. E.g., in case of a <Modal> component, the screen size directly affects the layout of components inside modal; in the case of uncontrolled <TextInput> component, the text inside the input affects the layout of the surrounding components. `State` is a special (legit!) workaround for all those similar cases. Native part of React Native maintains a special shared object between all nodes of the same family and use that during cloning and commits. See coming commits to know how to use that. In the near future State will fully replace LocalData concept but for simplicity they both exist for now. Reviewed By: mdvacca Differential Revision: D14217184 fbshipit-source-id: 6e018c5b68208d662462013bce0f4e2733d2f673
58 lines
1.2 KiB
C++
58 lines
1.2 KiB
C++
/**
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* Copyright (c) Facebook, Inc. and its affiliates.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*/
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#pragma once
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#include <memory>
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namespace facebook {
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namespace react {
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class ShadowNode;
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/*
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* Represents an entity that receives state update.
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* Practically, just a wrapper around shared a pointer to ShadowNode. We need
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* this mostly to avoid circular dependency problems.
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*/
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class StateTarget {
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public:
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/*
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* Creates an empty target.
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*/
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StateTarget();
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/*
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* Creates a target which points to a given `ShadowNode`.
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*/
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StateTarget(const ShadowNode &shadowNode);
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/*
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* Copyable and moveable.
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*/
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StateTarget(const StateTarget &other) = default;
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StateTarget &operator=(const StateTarget &other) = default;
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StateTarget(StateTarget &&other) noexcept = default;
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StateTarget &operator=(StateTarget &&other) = default;
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/*
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* Returns `true` is the target is not empty.
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*/
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operator bool() const;
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/*
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* Returns a reference to a stored `ShadowNode`.
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*/
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const ShadowNode &getShadowNode() const;
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private:
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std::shared_ptr<const void> shadowNode_;
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};
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} // namespace react
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} // namespace facebook
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