mirror of
https://github.com/facebook/react-native.git
synced 2025-11-01 09:14:26 +00:00
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
85 lines
2.5 KiB
C++
85 lines
2.5 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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#include "RootShadowNode.h"
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#include <react/components/view/conversions.h>
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#include <react/debug/SystraceSection.h>
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namespace facebook {
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namespace react {
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const char RootComponentName[] = "RootView";
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void RootShadowNode::layout(
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std::vector<LayoutableShadowNode const *> *affectedNodes) {
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SystraceSection s("RootShadowNode::layout");
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ensureUnsealed();
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auto layoutContext = getProps()->layoutContext;
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layoutContext.affectedNodes = affectedNodes;
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layout(layoutContext);
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// This is the rare place where shadow node must layout (set `layoutMetrics`)
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// itself because there is no a parent node which usually should do it.
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if (getHasNewLayout()) {
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setLayoutMetrics(layoutMetricsFromYogaNode(yogaNode_));
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setHasNewLayout(false);
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}
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}
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UnsharedRootShadowNode RootShadowNode::clone(
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const LayoutConstraints &layoutConstraints,
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const LayoutContext &layoutContext) const {
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auto props = std::make_shared<const RootProps>(
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*getProps(), layoutConstraints, layoutContext);
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auto newRootShadowNode = std::make_shared<RootShadowNode>(
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*this,
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ShadowNodeFragment{
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/* .tag = */ ShadowNodeFragment::tagPlaceholder(),
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/* .surfaceId = */ ShadowNodeFragment::surfaceIdPlaceholder(),
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/* .props = */ props,
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});
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return newRootShadowNode;
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}
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UnsharedRootShadowNode RootShadowNode::clone(
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SharedShadowNode const &oldShadowNode,
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SharedShadowNode const &newShadowNode) const {
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auto ancestors = oldShadowNode->getAncestors(*this);
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if (ancestors.size() == 0) {
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return UnsharedRootShadowNode{nullptr};
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}
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auto childNode = newShadowNode;
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for (auto it = ancestors.rbegin(); it != ancestors.rend(); ++it) {
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auto &parentNode = it->first.get();
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auto childIndex = it->second;
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auto children = parentNode.getChildren();
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assert(ShadowNode::sameFamily(*children.at(childIndex), *childNode));
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children[childIndex] = childNode;
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childNode = parentNode.clone({
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ShadowNodeFragment::tagPlaceholder(),
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ShadowNodeFragment::surfaceIdPlaceholder(),
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ShadowNodeFragment::propsPlaceholder(),
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ShadowNodeFragment::eventEmitterPlaceholder(),
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std::make_shared<SharedShadowNodeList>(children),
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});
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}
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return std::const_pointer_cast<RootShadowNode>(
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std::static_pointer_cast<RootShadowNode const>(childNode));
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}
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} // namespace react
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} // namespace facebook
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