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https://github.com/zhigang1992/react-native.git
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a9049442f7
Summary: Use a folly LRU implementation to cache results of ParagraphShadowNode::measure, which Yoga asks for repeatedly. Should have a substantial speed improvement on Android and iOS, or at least that's the dream. Reviewed By: mdvacca Differential Revision: D13795808 fbshipit-source-id: 5716af0fe0517a72716e48113c8125bb788735d7
83 lines
2.5 KiB
C++
83 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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#pragma once
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#include <folly/Optional.h>
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#include <react/components/text/ParagraphMeasurementCache.h>
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#include <react/components/text/ParagraphProps.h>
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#include <react/components/text/TextShadowNode.h>
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#include <react/components/view/ConcreteViewShadowNode.h>
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#include <react/core/ConcreteShadowNode.h>
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#include <react/core/LayoutContext.h>
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#include <react/core/ShadowNode.h>
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#include <react/textlayoutmanager/TextLayoutManager.h>
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namespace facebook {
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namespace react {
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extern const char ParagraphComponentName[];
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using ParagraphEventEmitter = ViewEventEmitter;
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/*
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* `ShadowNode` for <Paragraph> component, represents <View>-like component
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* containing and displaying text. Text content is represented as nested <Text>
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* and <RawText> components.
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*/
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class ParagraphShadowNode : public ConcreteViewShadowNode<
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ParagraphComponentName,
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ParagraphProps,
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ParagraphEventEmitter>,
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public BaseTextShadowNode {
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public:
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using ConcreteViewShadowNode::ConcreteViewShadowNode;
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/*
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* Returns a `AttributedString` which represents text content of the node.
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*/
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AttributedString getAttributedString() const;
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/*
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* Associates a shared TextLayoutManager with the node.
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* `ParagraphShadowNode` uses the manager to measure text content
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* and construct `ParagraphLocalData` objects.
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*/
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void setTextLayoutManager(SharedTextLayoutManager textLayoutManager);
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/*
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* Associates a shared LRU cache with the node.
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* `ParagraphShadowNode` uses this to cache the results of
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* text rendering measurements.
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*/
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void setMeasureCache(SharedParagraphMeasurementCache cache);
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#pragma mark - LayoutableShadowNode
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void layout(LayoutContext layoutContext) override;
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Size measure(LayoutConstraints layoutConstraints) const override;
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private:
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/*
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* Creates a `LocalData` object (with `AttributedText` and
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* `TextLayoutManager`) if needed.
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*/
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void updateLocalDataIfNeeded();
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SharedTextLayoutManager textLayoutManager_;
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SharedParagraphMeasurementCache measureCache_;
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/*
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* Cached attributed string that represents the content of the subtree started
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* from the node.
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*/
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mutable folly::Optional<AttributedString> cachedAttributedString_{};
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};
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} // namespace react
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} // namespace facebook
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