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https://github.com/facebook/react-native.git
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Valentin Shergin
ea8a57116f
Summary: Previously we computed the list of nodes that need to be notified about layout changes using a list of mutation instructions. That was fine, but that's not really compatible with some other changes that I plan to make, so I decided to change it (make it better). Besides the better design (debatable; fewer dependencies to unrelated moving pieces), here is why I believe the new way is more performant: * The new approach has no `dynamic_casts`, whereas the previous has tons of them (two per a mutation). If a `dynamic_cast` takes 10 ns, for 500 nodes it can take up to 5ms only for casts. (Non-scientific assumption.) * After removing dependency to mutation instruction, we can enable flattening for views which have `onLayout` event. Reviewed By: mdvacca Differential Revision: D15110725 fbshipit-source-id: 31a657ccfd02441734ad1d71a833653223163289
65 lines
1.8 KiB
C++
65 lines
1.8 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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#include <react/components/root/RootProps.h>
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#include <react/components/view/ConcreteViewShadowNode.h>
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#include <react/core/LayoutContext.h>
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namespace facebook {
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namespace react {
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class RootShadowNode;
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using SharedRootShadowNode = std::shared_ptr<const RootShadowNode>;
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using UnsharedRootShadowNode = std::shared_ptr<RootShadowNode>;
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extern const char RootComponentName[];
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/*
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* `ShadowNode` for the root component.
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* Besides all functionality of the `View` component, `RootShadowNode` contains
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* props which represent external layout constraints and context of the
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* shadow tree.
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*/
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class RootShadowNode final
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: public ConcreteViewShadowNode<RootComponentName, RootProps> {
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public:
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using ConcreteViewShadowNode::ConcreteViewShadowNode;
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/*
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* Layouts the shadow tree.
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*/
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void layout(std::vector<LayoutableShadowNode const *> *affectedNodes = {});
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/*
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* Clones the node with given `layoutConstraints` and `layoutContext`.
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*/
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UnsharedRootShadowNode clone(
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const LayoutConstraints &layoutConstraints,
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const LayoutContext &layoutContext) const;
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/*
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* Clones the node replacing a given old shadow node with a new one in the
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* tree by cloning all nodes on the path to the root node and then complete
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* the tree. Returns `nullptr` if the operation cannot be finished
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* successfully.
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*/
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UnsharedRootShadowNode clone(
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const SharedShadowNode &oldShadowNode,
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const SharedShadowNode &newShadowNode) const;
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private:
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using YogaLayoutableShadowNode::layout;
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};
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} // namespace react
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} // namespace facebook
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