mirror of
https://github.com/facebook/react-native.git
synced 2025-11-01 09:14:26 +00:00
Joshua Gross
4804e68238
Summary: Fabric core uses a lot of traits - I am reserving a few more for core usage, and also exposing a few "unreserved" traits. It is recommended that all custom components that do use traits rely on these constants instead of hard-coding any trait values. That way, in the unlikely event that these values change in the future, it will not break components. Changelog: [Internal] Reviewed By: cortinico, RSNara Differential Revision: D30401743 fbshipit-source-id: fb2e8f5cf33c94e31a0c25a89055acfc4eccf066
124 lines
3.5 KiB
C++
124 lines
3.5 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 <cstdint>
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namespace facebook {
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namespace react {
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/*
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* A set of predefined traits associated with a particular `ShadowNode` class
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* and an instance of that class. Used for efficient checking for interface
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* conformance for and storing important flags.
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*/
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class ShadowNodeTraits {
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public:
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/*
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* Underlying type for the traits.
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* The first 23 bits are reserved for Core.
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*/
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enum Trait : int32_t {
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None = 0,
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// Note:
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// Not all traits are used yet (but all will be used in the near future).
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// Inherits `LayoutableShadowNode`.
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LayoutableKind = 1 << 0,
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// Inherits `YogaLayoutableShadowNode`.
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YogaLayoutableKind = 1 << 1,
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// Inherits `ConcreteViewShadowNode<>` template.
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ViewKind = 1 << 2,
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// Inherits `BaseTextShadowNode`.
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TextKind = 1 << 3,
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// Used when calculating relative layout in
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// LayoutableShadowNode::getRelativeLayoutMetrics. This trait marks node as
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// root, so when calculating relative layout, the calculation will not
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// traverse beyond this node. See T61257516 for details.
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RootNodeKind = 1 << 4,
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// `ViewShadowNode` (exact!) class.
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View = 1 << 5,
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// The node is hidden.
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// Nodes with this trait (and all their descendants) will not produce views.
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Hidden = 1 << 6,
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// Indicates that the `YogaLayoutableShadowNode` must set `isDirty` flag for
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// Yoga node when a `ShadowNode` is being cloned. `ShadowNode`s that modify
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// Yoga styles in the constructor (or later) *after* the `ShadowNode`
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// is cloned must set this trait.
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// Any Yoga node (not only Leaf ones) can have this trait.
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DirtyYogaNode = 1 << 9,
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// Inherits `YogaLayoutableShadowNode` and enforces that the `YGNode` is a
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// leaf.
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LeafYogaNode = 1 << 10,
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// Inherits `YogaLayoutableShadowNode` and has a custom measure function.
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// Only Leaf nodes can have this trait.
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MeasurableYogaNode = 1 << 11,
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// Indicates that the `ShadowNode` must form a stacking context.
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// A Stacking Context forms a level of a `ShadowView` hierarchy (in contrast
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// with a level of a `ShadowNode` hierarchy).
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// See W3C standard for more details: https://www.w3.org/TR/CSS2/zindex.html
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FormsStackingContext = 1 << 13,
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// Indicates that the node must form a `ShadowView`.
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FormsView = 1 << 14,
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// Internal to `ShadowNode`; do not use it outside.
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// Indicates that `children` list is shared between nodes and need
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// to be cloned before the first mutation.
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ChildrenAreShared = 1 << 15,
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// Inherits 'RawTextShadowNode'
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RawText = 1 << 16,
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// Inherits 'TextShadowNode'
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Text = 1 << 17,
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// Reserved
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ReservedTrait1 = 1 << 18,
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ReservedTrait2 = 1 << 19,
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ReservedTrait3 = 1 << 20,
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ReservedTrait4 = 1 << 21,
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ReservedTrait5 = 1 << 22,
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// Unserved - alias these for local usage
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UnreservedTrait1 = 1 << 23
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};
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/*
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* Sets, unsets, and checks individual traits.
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*/
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inline void set(Trait trait) {
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traits_ = ShadowNodeTraits::Trait(traits_ | trait);
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}
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inline void unset(Trait trait) {
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traits_ = ShadowNodeTraits::Trait(traits_ & ~trait);
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}
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inline bool check(Trait traits) const {
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return ShadowNodeTraits::Trait(traits_ & traits) == traits;
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}
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private:
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Trait traits_{Trait::None};
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};
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} // namespace react
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} // namespace facebook
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