mirror of
https://github.com/facebook/react-native.git
synced 2025-11-01 09:14:26 +00:00
Samuel Susla
5fa6c5a941
Summary: changelog: [internal] You can read more about this rule on https://clang.llvm.org/extra/clang-tidy/checks/modernize-pass-by-value.html # Isn't it wasteful to copy? Isn't reference more efficient? This rule of thumb is no longer true since C++11 with move semantics. Let's look at some examples. # Option one ``` class TextHolder { public: TextBox(std::string const &text) : text_(text) {} private: std::string text_; }; ``` By using reference here, we prevent the caller from using rvalue to and avoiding copy. Regardless of what the caller passes in, copy always happens. # Option two ``` class TextHolder { public: TextBox(std::string const &text) : text_(text) {} TextBox(std::string &&text) : text_(std::move(text)) {} private: std::string text_; }; ``` Here, we provide two constructors, one for const reference and one for rvalue reference. This gives the caller option to avoid copy. But now we have two constructors, which is not ideal. # Option three (what we do in this diff) ``` class TextHolder { public: TextBox(std::string text) : text_(std::move(text)) {} private: std::string text_; }; ``` Here, the caller has option to avoid copy and we only have single constructor. Reviewed By: fkgozali, JoshuaGross Differential Revision: D33276841 fbshipit-source-id: 619d5123d2e28937b22874650366629f24f20a63
48 lines
1.3 KiB
C++
48 lines
1.3 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 <string>
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#include <react/renderer/debug/DebugStringConvertible.h>
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namespace facebook {
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namespace react {
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#if RN_DEBUG_STRING_CONVERTIBLE
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// Trivial implementation of `DebugStringConvertible` abstract class
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// with a stored output; useful for assembling `DebugStringConvertible` values
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// in custom implementations of `getDebugChildren` and `getDebugProps`.
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class DebugStringConvertibleItem : public DebugStringConvertible {
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public:
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DebugStringConvertibleItem(const DebugStringConvertibleItem &item) = default;
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DebugStringConvertibleItem(
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std::string name = "",
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std::string value = "",
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SharedDebugStringConvertibleList props = {},
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SharedDebugStringConvertibleList children = {});
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std::string getDebugName() const override;
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std::string getDebugValue() const override;
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SharedDebugStringConvertibleList getDebugChildren() const override;
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SharedDebugStringConvertibleList getDebugProps() const override;
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private:
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std::string name_;
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std::string value_;
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SharedDebugStringConvertibleList debugProps_;
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SharedDebugStringConvertibleList children_;
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};
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#endif
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} // namespace react
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} // namespace facebook
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