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<ol class="chapter"><li class="chapter-item affix "><a href="../../about-book.html">关于本书</a></li><li class="chapter-item affix "><a href="../../into-rust.html">进入 Rust 编程世界</a></li><li class="chapter-item affix "><a href="../../first-try/sth-you-should-not-do.html">避免从入门到放弃</a></li><li class="chapter-item affix "><a href="../../community.html">社区和锈书</a></li><li class="spacer"></li><li class="chapter-item affix "><a href="../../some-thoughts.html">Xobserve: 一切皆可观测</a></li><li class="chapter-item affix "><a href="../../beat-ai.html">BeatAI: 工程师 AI 入门圣经</a></li><li class="chapter-item affix "><li class="part-title">Rust 语言基础学习</li><li class="spacer"></li><li class="chapter-item "><a href="../../first-try/intro.html"><strong aria-hidden="true">1.</strong> 寻找牛刀，以便小试</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../first-try/installation.html"><strong aria-hidden="true">1.1.</strong> 安装 Rust 环境</a></li><li class="chapter-item "><a href="../../first-try/editor.html"><strong aria-hidden="true">1.2.</strong> 墙推 VSCode!</a></li><li class="chapter-item "><a href="../../first-try/cargo.html"><strong aria-hidden="true">1.3.</strong> 认识 Cargo</a></li><li class="chapter-item "><a href="../../first-try/hello-world.html"><strong aria-hidden="true">1.4.</strong> 不仅仅是 Hello world</a></li><li class="chapter-item "><a href="../../first-try/slowly-downloading.html"><strong aria-hidden="true">1.5.</strong> 下载依赖太慢了？</a></li></ol></li><li class="chapter-item "><a href="../../basic/intro.html"><strong aria-hidden="true">2.</strong> Rust 基础入门</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../basic/variable.html"><strong aria-hidden="true">2.1.</strong> 变量绑定与解构</a></li><li class="chapter-item "><a href="../../basic/base-type/index.html"><strong aria-hidden="true">2.2.</strong> 基本类型</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../basic/base-type/numbers.html"><strong aria-hidden="true">2.2.1.</strong> 数值类型</a></li><li class="chapter-item "><a href="../../basic/base-type/char-bool.html"><strong aria-hidden="true">2.2.2.</strong> 字符、布尔、单元类型</a></li><li class="chapter-item "><a href="../../basic/base-type/statement-expression.html"><strong aria-hidden="true">2.2.3.</strong> 语句与表达式</a></li><li class="chapter-item "><a href="../../basic/base-type/function.html"><strong aria-hidden="true">2.2.4.</strong> 函数</a></li></ol></li><li class="chapter-item "><a href="../../basic/ownership/index.html"><strong aria-hidden="true">2.3.</strong> 所有权和借用</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../basic/ownership/ownership.html"><strong aria-hidden="true">2.3.1.</strong> 所有权</a></li><li class="chapter-item "><a href="../../basic/ownership/borrowing.html"><strong aria-hidden="true">2.3.2.</strong> 引用与借用</a></li></ol></li><li class="chapter-item "><a href="../../basic/compound-type/intro.html"><strong aria-hidden="true">2.4.</strong> 复合类型</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../basic/compound-type/string-slice.html"><strong aria-hidden="true">2.4.1.</strong> 字符串与切片</a></li><li class="chapter-item "><a href="../../basic/compound-type/tuple.html"><strong aria-hidden="true">2.4.2.</strong> 元组</a></li><li class="chapter-item "><a href="../../basic/compound-type/struct.html"><strong aria-hidden="true">2.4.3.</strong> 结构体</a></li><li class="chapter-item "><a href="../../basic/compound-type/enum.html"><strong aria-hidden="true">2.4.4.</strong> 枚举</a></li><li class="chapter-item "><a href="../../basic/compound-type/array.html"><strong aria-hidden="true">2.4.5.</strong> 数组</a></li></ol></li><li class="chapter-item "><a href="../../basic/flow-control.html"><strong aria-hidden="true">2.5.</strong> 流程控制</a></li><li class="chapter-item "><a href="../../basic/match-pattern/intro.html"><strong aria-hidden="true">2.6.</strong> 模式匹配</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../basic/match-pattern/match-if-let.html"><strong aria-hidden="true">2.6.1.</strong> match 和 if let</a></li><li class="chapter-item "><a href="../../basic/match-pattern/option.html"><strong aria-hidden="true">2.6.2.</strong> 解构 Option</a></li><li class="chapter-item "><a href="../../basic/match-pattern/pattern-match.html"><strong aria-hidden="true">2.6.3.</strong> 模式适用场景</a></li><li class="chapter-item "><a href="../../basic/match-pattern/all-patterns.html"><strong aria-hidden="true">2.6.4.</strong> 全模式列表</a></li></ol></li><li class="chapter-item "><a href="../../basic/method.html"><strong aria-hidden="true">2.7.</strong> 方法 Method</a></li><li class="chapter-item "><a href="../../basic/trait/intro.html"><strong aria-hidden="true">2.8.</strong> 泛型和特征</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../basic/trait/generic.html"><strong aria-hidden="true">2.8.1.</strong> 泛型 Generics</a></li><li class="chapter-item "><a href="../../basic/trait/trait.html"><strong aria-hidden="true">2.8.2.</strong> 特征 Trait</a></li><li class="chapter-item "><a href="../../basic/trait/trait-object.html"><strong aria-hidden="true">2.8.3.</strong> 特征对象</a></li><li class="chapter-item "><a href="../../basic/trait/advance-trait.html"><strong aria-hidden="true">2.8.4.</strong> 进一步深入特征</a></li></ol></li><li class="chapter-item "><a href="../../basic/collections/intro.html"><strong aria-hidden="true">2.9.</strong> 集合类型</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../basic/collections/vector.html"><strong aria-hidden="true">2.9.1.</strong> 动态数组 Vector</a></li><li class="chapter-item "><a href="../../basic/collections/hashmap.html"><strong aria-hidden="true">2.9.2.</strong> KV 存储 HashMap</a></li></ol></li><li class="chapter-item "><a href="../../basic/lifetime.html"><strong aria-hidden="true">2.10.</strong> 认识生命周期</a></li><li class="chapter-item "><a href="../../basic/result-error/intro.html"><strong aria-hidden="true">2.11.</strong> 返回值和错误处理</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../basic/result-error/panic.html"><strong aria-hidden="true">2.11.1.</strong> panic! 深入剖析</a></li><li class="chapter-item "><a href="../../basic/result-error/result.html"><strong aria-hidden="true">2.11.2.</strong> 返回值 Result 和?</a></li></ol></li><li class="chapter-item "><a href="../../basic/crate-module/intro.html"><strong aria-hidden="true">2.12.</strong> 包和模块</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../basic/crate-module/crate.html"><strong aria-hidden="true">2.12.1.</strong> 包 Crate</a></li><li class="chapter-item "><a href="../../basic/crate-module/module.html"><strong aria-hidden="true">2.12.2.</strong> 模块 Module</a></li><li class="chapter-item "><a href="../../basic/crate-module/use.html"><strong aria-hidden="true">2.12.3.</strong> 使用 use 引入模块及受限可见性</a></li></ol></li><li class="chapter-item "><a href="../../basic/comment.html"><strong aria-hidden="true">2.13.</strong> 注释和文档</a></li><li class="chapter-item "><a href="../../basic/formatted-output.html"><strong aria-hidden="true">2.14.</strong> 格式化输出</a></li></ol></li><li class="chapter-item "><a href="../../basic-practice/intro.html"><strong aria-hidden="true">3.</strong> 入门实战：文件搜索工具</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../basic-practice/base-features.html"><strong aria-hidden="true">3.1.</strong> 基本功能</a></li><li class="chapter-item "><a href="../../basic-practice/refactoring.html"><strong aria-hidden="true">3.2.</strong> 增加模块化和错误处理</a></li><li class="chapter-item "><a href="../../basic-practice/tests.html"><strong aria-hidden="true">3.3.</strong> 测试驱动开发</a></li><li class="chapter-item "><a href="../../basic-practice/envs.html"><strong aria-hidden="true">3.4.</strong> 使用环境变量</a></li><li class="chapter-item "><a href="../../basic-practice/stderr.html"><strong aria-hidden="true">3.5.</strong> 重定向错误信息的输出</a></li><li class="chapter-item "><a href="../../basic-practice/iterators.html"><strong aria-hidden="true">3.6.</strong> 使用迭代器来改进程序(可选)</a></li></ol></li><li class="chapter-item "><li class="part-title">Rust 语言进阶学习</li><li class="spacer"></li><li class="chapter-item expanded "><a href="../../advance/intro.html"><strong aria-hidden="true">4.</strong> Rust 高级进阶</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../advance/lifetime/intro.html"><strong aria-hidden="true">4.1.</strong> 生命周期</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../advance/lifetime/advance.html"><strong aria-hidden="true">4.1.1.</strong> 深入生命周期</a></li><li class="chapter-item "><a href="../../advance/lifetime/static.html"><strong aria-hidden="true">4.1.2.</strong> &'static 和 T: 'static</a></li></ol></li><li class="chapter-item "><a href="../../advance/functional-programing/intro.html"><strong aria-hidden="true">4.2.</strong> 函数式编程: 闭包、迭代器</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../advance/functional-programing/closure.html"><strong aria-hidden="true">4.2.1.</strong> 闭包 Closure</a></li><li class="chapter-item "><a href="../../advance/functional-programing/iterator.html"><strong aria-hidden="true">4.2.2.</strong> 迭代器 Iterator</a></li></ol></li><li class="chapter-item "><a href="../../advance/into-types/intro.html"><strong aria-hidden="true">4.3.</strong> 深入类型</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../advance/into-types/converse.html"><strong aria-hidden="true">4.3.1.</strong> 类型转换</a></li><li class="chapter-item "><a href="../../advance/into-types/custom-type.html"><strong aria-hidden="true">4.3.2.</strong> newtype 和 类型别名</a></li><li class="chapter-item "><a href="../../advance/into-types/sized.html"><strong aria-hidden="true">4.3.3.</strong> Sized 和不定长类型 DST</a></li><li class="chapter-item "><a href="../../advance/into-types/enum-int.html"><strong aria-hidden="true">4.3.4.</strong> 枚举和整数</a></li></ol></li><li class="chapter-item "><a href="../../advance/smart-pointer/intro.html"><strong aria-hidden="true">4.4.</strong> 智能指针</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../advance/smart-pointer/box.html"><strong aria-hidden="true">4.4.1.</strong> Box堆对象分配</a></li><li class="chapter-item "><a href="../../advance/smart-pointer/deref.html"><strong aria-hidden="true">4.4.2.</strong> Deref 解引用</a></li><li class="chapter-item "><a href="../../advance/smart-pointer/drop.html"><strong aria-hidden="true">4.4.3.</strong> Drop 释放资源</a></li><li class="chapter-item "><a href="../../advance/smart-pointer/rc-arc.html"><strong aria-hidden="true">4.4.4.</strong> Rc 与 Arc 实现 1vN 所有权机制</a></li><li class="chapter-item "><a href="../../advance/smart-pointer/cell-refcell.html"><strong aria-hidden="true">4.4.5.</strong> Cell 与 RefCell 内部可变性</a></li></ol></li><li class="chapter-item "><a href="../../advance/circle-self-ref/intro.html"><strong aria-hidden="true">4.5.</strong> 循环引用与自引用</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../advance/circle-self-ref/circle-reference.html"><strong aria-hidden="true">4.5.1.</strong> Weak 与循环引用</a></li><li class="chapter-item "><a href="../../advance/circle-self-ref/self-referential.html"><strong aria-hidden="true">4.5.2.</strong> 结构体中的自引用</a></li></ol></li><li class="chapter-item "><a href="../../advance/concurrency-with-threads/intro.html"><strong aria-hidden="true">4.6.</strong> 多线程并发编程</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../advance/concurrency-with-threads/concurrency-parallelism.html"><strong aria-hidden="true">4.6.1.</strong> 并发和并行</a></li><li class="chapter-item "><a href="../../advance/concurrency-with-threads/thread.html"><strong aria-hidden="true">4.6.2.</strong> 使用多线程</a></li><li class="chapter-item "><a href="../../advance/concurrency-with-threads/message-passing.html"><strong aria-hidden="true">4.6.3.</strong> 线程同步：消息传递</a></li><li class="chapter-item "><a href="../../advance/concurrency-with-threads/sync1.html"><strong aria-hidden="true">4.6.4.</strong> 线程同步：锁、Condvar 和信号量</a></li><li class="chapter-item "><a href="../../advance/concurrency-with-threads/sync2.html"><strong aria-hidden="true">4.6.5.</strong> 线程同步：Atomic 原子操作与内存顺序</a></li><li class="chapter-item "><a href="../../advance/concurrency-with-threads/send-sync.html"><strong aria-hidden="true">4.6.6.</strong> 基于 Send 和 Sync 的线程安全</a></li></ol></li><li class="chapter-item "><a href="../../advance/global-variable.html"><strong aria-hidden="true">4.7.</strong> 全局变量</a></li><li class="chapter-item "><a href="../../advance/errors.html"><strong aria-hidden="true">4.8.</strong> 错误处理</a></li><li class="chapter-item "><a href="../../advance/unsafe/intro.html"><strong aria-hidden="true">4.9.</strong> Unsafe Rust</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../advance/unsafe/superpowers.html"><strong aria-hidden="true">4.9.1.</strong> 五种兵器</a></li><li class="chapter-item "><a href="../../advance/unsafe/inline-asm.html"><strong aria-hidden="true">4.9.2.</strong> 内联汇编</a></li></ol></li><li class="chapter-item "><a href="../../advance/macro.html"><strong aria-hidden="true">4.10.</strong> Macro 宏编程</a></li><li class="chapter-item expanded "><a href="../../advance/async/intro.html"><strong aria-hidden="true">4.11.</strong> async/await 异步编程</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../advance/async/getting-started.html"><strong aria-hidden="true">4.11.1.</strong> async 编程入门</a></li><li class="chapter-item "><a href="../../advance/async/future-excuting.html"><strong aria-hidden="true">4.11.2.</strong> 底层探秘: Future 执行与任务调度</a></li><li class="chapter-item expanded "><a href="../../advance/async/pin-unpin.html" class="active"><strong aria-hidden="true">4.11.3.</strong> 定海神针 Pin 和 Unpin</a></li><li class="chapter-item "><a href="../../advance/async/async-await.html"><strong aria-hidden="true">4.11.4.</strong> async/await 和 Stream 流处理</a></li><li class="chapter-item "><a href="../../advance/async/multi-futures-simultaneous.html"><strong aria-hidden="true">4.11.5.</strong> 同时运行多个 Future</a></li><li class="chapter-item "><a href="../../advance/async/pain-points-and-workarounds.html"><strong aria-hidden="true">4.11.6.</strong> 一些疑难问题的解决办法</a></li><li class="chapter-item "><a href="../../advance/async/web-server.html"><strong aria-hidden="true">4.11.7.</strong> 实践应用：Async Web 服务器</a></li></ol></li></ol></li><li class="chapter-item "><a href="../../advance-practice1/intro.html"><strong aria-hidden="true">5.</strong> 进阶实战1: 实现一个 web 服务器</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../advance-practice1/web-server.html"><strong aria-hidden="true">5.1.</strong> 单线程版本</a></li><li class="chapter-item "><a href="../../advance-practice1/multi-threads.html"><strong aria-hidden="true">5.2.</strong> 多线程版本</a></li><li class="chapter-item "><a href="../../advance-practice1/graceful-shutdown.html"><strong aria-hidden="true">5.3.</strong> 优雅关闭和资源清理</a></li></ol></li><li class="chapter-item "><a href="../../advance-practice/intro.html"><strong aria-hidden="true">6.</strong> 进阶实战2: 实现一个简单 Redis</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../advance-practice/overview.html"><strong aria-hidden="true">6.1.</strong> tokio 概览</a></li><li class="chapter-item "><a href="../../advance-practice/getting-startted.html"><strong aria-hidden="true">6.2.</strong> 使用初印象</a></li><li class="chapter-item "><a href="../../advance-practice/spawning.html"><strong aria-hidden="true">6.3.</strong> 创建异步任务</a></li><li class="chapter-item "><a href="../../advance-practice/shared-state.html"><strong aria-hidden="true">6.4.</strong> 共享状态</a></li><li class="chapter-item "><a href="../../advance-practice/channels.html"><strong aria-hidden="true">6.5.</strong> 消息传递</a></li><li class="chapter-item "><a href="../../advance-practice/io.html"><strong aria-hidden="true">6.6.</strong> I/O</a></li><li class="chapter-item "><a href="../../advance-practice/frame.html"><strong aria-hidden="true">6.7.</strong> 解析数据帧</a></li><li class="chapter-item "><a href="../../advance-practice/async.html"><strong aria-hidden="true">6.8.</strong> 深入 async</a></li><li class="chapter-item "><a href="../../advance-practice/select.html"><strong aria-hidden="true">6.9.</strong> select</a></li><li class="chapter-item "><a href="../../advance-practice/stream.html"><strong aria-hidden="true">6.10.</strong> 类似迭代器的 Stream</a></li><li class="chapter-item "><a href="../../advance-practice/graceful-shutdown.html"><strong aria-hidden="true">6.11.</strong> 优雅的关闭</a></li><li class="chapter-item "><a href="../../advance-practice/bridging-with-sync.html"><strong aria-hidden="true">6.12.</strong> 异步跟同步共存</a></li></ol></li><li class="chapter-item "><a href="../../difficulties/intro.html"><strong aria-hidden="true">7.</strong> Rust 难点攻关</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../difficulties/slice.html"><strong aria-hidden="true">7.1.</strong> 切片和切片引用</a></li><li class="chapter-item "><a href="../../difficulties/eq.html"><strong aria-hidden="true">7.2.</strong> Eq 和 PartialEq</a></li><li class="chapter-item "><a href="../../difficulties/string.html"><strong aria-hidden="true">7.3.</strong> String、&str 和 str TODO</a></li><li class="chapter-item "><a href="../../difficulties/lifetime.html"><strong aria-hidden="true">7.4.</strong> 作用域、生命周期和 NLL TODO</a></li><li class="chapter-item "><a href="../../difficulties/move-copy.html"><strong aria-hidden="true">7.5.</strong> move、Copy 和 Clone TODO</a></li><li class="chapter-item "><a href="../../advance/difficulties/pointer.html"><strong aria-hidden="true">7.6.</strong> 裸指针、引用和智能指针 TODO</a></li></ol></li><li class="chapter-item "><li class="part-title">常用工具链</li><li class="spacer"></li><li class="chapter-item "><a href="../../test/intro.html"><strong aria-hidden="true">8.</strong> 自动化测试</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../test/write-tests.html"><strong aria-hidden="true">8.1.</strong> 编写测试及控制执行</a></li><li class="chapter-item "><a href="../../test/unit-integration-test.html"><strong aria-hidden="true">8.2.</strong> 单元测试和集成测试</a></li><li class="chapter-item "><a href="../../test/assertion.html"><strong aria-hidden="true">8.3.</strong> 断言 assertion</a></li><li class="chapter-item "><a href="../../test/ci.html"><strong aria-hidden="true">8.4.</strong> 用 GitHub Actions 进行持续集成</a></li><li class="chapter-item "><a href="../../test/benchmark.html"><strong aria-hidden="true">8.5.</strong> 基准测试 benchmark</a></li></ol></li><li class="chapter-item "><a href="../../cargo/intro.html"><strong aria-hidden="true">9.</strong> Cargo 使用指南</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../cargo/getting-started.html"><strong aria-hidden="true">9.1.</strong> 上手使用</a></li><li class="chapter-item "><a href="../../cargo/guide/intro.html"><strong aria-hidden="true">9.2.</strong> 基础指南</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../cargo/guide/why-exist.html"><strong aria-hidden="true">9.2.1.</strong> 为何会有 Cargo</a></li><li class="chapter-item "><a href="../../cargo/guide/download-package.html"><strong aria-hidden="true">9.2.2.</strong> 下载并构建 Package</a></li><li class="chapter-item "><a href="../../cargo/guide/dependencies.html"><strong aria-hidden="true">9.2.3.</strong> 添加依赖</a></li><li class="chapter-item "><a href="../../cargo/guide/package-layout.html"><strong aria-hidden="true">9.2.4.</strong> Package 目录结构</a></li><li class="chapter-item "><a href="../../cargo/guide/cargo-toml-lock.html"><strong aria-hidden="true">9.2.5.</strong> Cargo.toml vs Cargo.lock</a></li><li class="chapter-item "><a href="../../cargo/guide/tests-ci.html"><strong aria-hidden="true">9.2.6.</strong> 测试和 CI</a></li><li class="chapter-item "><a href="../../cargo/guide/cargo-cache.html"><strong aria-hidden="true">9.2.7.</strong> Cargo 缓存</a></li><li class="chapter-item "><a href="../../cargo/guide/build-cache.html"><strong aria-hidden="true">9.2.8.</strong> Build 缓存</a></li></ol></li><li class="chapter-item "><a href="../../cargo/reference/intro.html"><strong aria-hidden="true">9.3.</strong> 进阶指南</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../cargo/reference/specify-deps.html"><strong aria-hidden="true">9.3.1.</strong> 指定依赖项</a></li><li class="chapter-item "><a href="../../cargo/reference/deps-overriding.html"><strong aria-hidden="true">9.3.2.</strong> 依赖覆盖</a></li><li class="chapter-item "><a href="../../cargo/reference/manifest.html"><strong aria-hidden="true">9.3.3.</strong> Cargo.toml 清单详解</a></li><li class="chapter-item "><a href="../../cargo/reference/cargo-target.html"><strong aria-hidden="true">9.3.4.</strong> Cargo Target</a></li><li class="chapter-item "><a href="../../cargo/reference/workspaces.html"><strong aria-hidden="true">9.3.5.</strong> 工作空间 Workspace</a></li><li class="chapter-item "><a href="../../cargo/reference/features/intro.html"><strong aria-hidden="true">9.3.6.</strong> 条件编译 Features</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../cargo/reference/features/examples.html"><strong aria-hidden="true">9.3.6.1.</strong> Features 示例</a></li></ol></li><li class="chapter-item "><a href="../../cargo/reference/profiles.html"><strong aria-hidden="true">9.3.7.</strong> 发布配置 Profile</a></li><li class="chapter-item "><a href="../../cargo/reference/configuration.html"><strong aria-hidden="true">9.3.8.</strong> 通过 config.toml 对 Cargo 进行配置</a></li><li class="chapter-item "><a href="../../cargo/reference/publishing-on-crates.io.html"><strong aria-hidden="true">9.3.9.</strong> 发布到 crates.io</a></li><li class="chapter-item "><a href="../../cargo/reference/build-script/intro.html"><strong aria-hidden="true">9.3.10.</strong> 构建脚本 build.rs</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../cargo/reference/build-script/examples.html"><strong aria-hidden="true">9.3.10.1.</strong> 构建脚本示例</a></li></ol></li></ol></li></ol></li><li class="chapter-item "><li class="part-title">开发实践</li><li class="spacer"></li><li class="chapter-item "><a href="../../usecases/intro.html"><strong aria-hidden="true">10.</strong> 企业落地实践</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../usecases/aws-rust.html"><strong aria-hidden="true">10.1.</strong> AWS 为何这么喜欢 Rust?</a></li></ol></li><li class="chapter-item "><a href="../../logs/intro.html"><strong aria-hidden="true">11.</strong> 日志和监控</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../logs/about-log.html"><strong aria-hidden="true">11.1.</strong> 日志详解</a></li><li class="chapter-item "><a href="../../logs/log.html"><strong aria-hidden="true">11.2.</strong> 日志门面 log</a></li><li class="chapter-item "><a href="../../logs/tracing.html"><strong aria-hidden="true">11.3.</strong> 使用 tracing 记录日志</a></li><li class="chapter-item "><a href="../../logs/tracing-logger.html"><strong aria-hidden="true">11.4.</strong> 自定义 tracing 的输出格式</a></li><li class="chapter-item "><a href="../../logs/observe/intro.html"><strong aria-hidden="true">11.5.</strong> 监控</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../logs/observe/about-observe.html"><strong aria-hidden="true">11.5.1.</strong> 可观测性</a></li><li class="chapter-item "><a href="../../logs/observe/trace.html"><strong aria-hidden="true">11.5.2.</strong> 分布式追踪</a></li></ol></li></ol></li><li class="chapter-item "><a href="../../practice/intro.html"><strong aria-hidden="true">12.</strong> Rust 最佳实践</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../practice/third-party-libs.html"><strong aria-hidden="true">12.1.</strong> 日常开发三方库精选</a></li><li class="chapter-item "><a href="../../practice/naming.html"><strong aria-hidden="true">12.2.</strong> 命名规范</a></li><li class="chapter-item "><a href="../../practice/interview.html"><strong aria-hidden="true">12.3.</strong> 面试经验</a></li><li class="chapter-item "><a href="../../practice/best-pratice.html"><strong aria-hidden="true">12.4.</strong> 代码开发实践 todo</a></li></ol></li><li class="chapter-item "><a href="../../too-many-lists/intro.html"><strong aria-hidden="true">13.</strong> 手把手带你实现链表</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../too-many-lists/do-we-need-it.html"><strong aria-hidden="true">13.1.</strong> 我们到底需不需要链表</a></li><li class="chapter-item "><a href="../../too-many-lists/bad-stack/intro.html"><strong aria-hidden="true">13.2.</strong> 不太优秀的单向链表：栈</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../too-many-lists/bad-stack/layout.html"><strong aria-hidden="true">13.2.1.</strong> 数据布局</a></li><li class="chapter-item "><a href="../../too-many-lists/bad-stack/basic-operations.html"><strong aria-hidden="true">13.2.2.</strong> 基本操作</a></li><li class="chapter-item "><a href="../../too-many-lists/bad-stack/final-code.html"><strong aria-hidden="true">13.2.3.</strong> 最后实现</a></li></ol></li><li class="chapter-item "><a href="../../too-many-lists/ok-stack/intro.html"><strong aria-hidden="true">13.3.</strong> 还可以的单向链表</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../too-many-lists/ok-stack/type-optimizing.html"><strong aria-hidden="true">13.3.1.</strong> 优化类型定义</a></li><li class="chapter-item "><a href="../../too-many-lists/ok-stack/peek.html"><strong aria-hidden="true">13.3.2.</strong> 定义 Peek 函数</a></li><li class="chapter-item "><a href="../../too-many-lists/ok-stack/iter.html"><strong aria-hidden="true">13.3.3.</strong> IntoIter 和 Iter</a></li><li class="chapter-item "><a href="../../too-many-lists/ok-stack/itermut.html"><strong aria-hidden="true">13.3.4.</strong> IterMut 以及完整代码</a></li></ol></li><li class="chapter-item "><a href="../../too-many-lists/persistent-stack/intro.html"><strong aria-hidden="true">13.4.</strong> 持久化单向链表</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../too-many-lists/persistent-stack/layout.html"><strong aria-hidden="true">13.4.1.</strong> 数据布局和基本操作</a></li><li class="chapter-item "><a href="../../too-many-lists/persistent-stack/drop-arc.html"><strong aria-hidden="true">13.4.2.</strong> Drop、Arc 及完整代码</a></li></ol></li><li class="chapter-item "><a href="../../too-many-lists/deque/intro.html"><strong aria-hidden="true">13.5.</strong> 不咋样的双端队列</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../too-many-lists/deque/layout.html"><strong aria-hidden="true">13.5.1.</strong> 数据布局和基本操作</a></li><li class="chapter-item "><a href="../../too-many-lists/deque/peek.html"><strong aria-hidden="true">13.5.2.</strong> Peek</a></li><li class="chapter-item "><a href="../../too-many-lists/deque/symmetric.html"><strong aria-hidden="true">13.5.3.</strong> 基本操作的对称镜像</a></li><li class="chapter-item "><a href="../../too-many-lists/deque/iterator.html"><strong aria-hidden="true">13.5.4.</strong> 迭代器</a></li><li class="chapter-item "><a href="../../too-many-lists/deque/final-code.html"><strong aria-hidden="true">13.5.5.</strong> 最终代码</a></li></ol></li><li class="chapter-item "><a href="../../too-many-lists/unsafe-queue/intro.html"><strong aria-hidden="true">13.6.</strong> 不错的 unsafe 队列</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../too-many-lists/unsafe-queue/layout.html"><strong aria-hidden="true">13.6.1.</strong> 数据布局</a></li><li class="chapter-item "><a href="../../too-many-lists/unsafe-queue/basics.html"><strong aria-hidden="true">13.6.2.</strong> 基本操作</a></li><li class="chapter-item "><a href="../../too-many-lists/unsafe-queue/miri.html"><strong aria-hidden="true">13.6.3.</strong> Miri</a></li><li class="chapter-item "><a href="../../too-many-lists/unsafe-queue/stacked-borrow.html"><strong aria-hidden="true">13.6.4.</strong> 栈借用</a></li><li class="chapter-item "><a href="../../too-many-lists/unsafe-queue/testing-stacked-borrow.html"><strong aria-hidden="true">13.6.5.</strong> 测试栈借用</a></li><li class="chapter-item "><a href="../../too-many-lists/unsafe-queue/layout2.html"><strong aria-hidden="true">13.6.6.</strong> 数据布局 2</a></li><li class="chapter-item "><a href="../../too-many-lists/unsafe-queue/extra-junk.html"><strong aria-hidden="true">13.6.7.</strong> 额外的操作</a></li><li class="chapter-item "><a href="../../too-many-lists/unsafe-queue/final-code.html"><strong aria-hidden="true">13.6.8.</strong> 最终代码</a></li></ol></li><li class="chapter-item "><a href="../../too-many-lists/production-unsafe-deque/intro.html"><strong aria-hidden="true">13.7.</strong> 生产级的双向 unsafe 队列</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../too-many-lists/production-unsafe-deque/layout.html"><strong aria-hidden="true">13.7.1.</strong> 数据布局</a></li><li class="chapter-item "><a href="../../too-many-lists/production-unsafe-deque/variance-and-phantomData.html"><strong aria-hidden="true">13.7.2.</strong> 型变与子类型</a></li><li class="chapter-item "><a href="../../too-many-lists/production-unsafe-deque/basics.html"><strong aria-hidden="true">13.7.3.</strong> 基础结构</a></li><li class="chapter-item "><a href="../../too-many-lists/production-unsafe-deque/drop-and-panic-safety.html"><strong aria-hidden="true">13.7.4.</strong> 恐慌与安全</a></li><li class="chapter-item "><a href="../../too-many-lists/production-unsafe-deque/boring-combinatorics.html"><strong aria-hidden="true">13.7.5.</strong> 无聊的组合</a></li><li class="chapter-item "><a href="../../too-many-lists/production-unsafe-deque/filling-in-random-bits.html"><strong aria-hidden="true">13.7.6.</strong> 其它特征</a></li><li class="chapter-item "><a href="../../too-many-lists/production-unsafe-deque/testing.html"><strong aria-hidden="true">13.7.7.</strong> 测试</a></li><li class="chapter-item "><a href="../../too-many-lists/production-unsafe-deque/send-sync-and-compile-tests.html"><strong aria-hidden="true">13.7.8.</strong> Send,Sync和编译测试</a></li><li class="chapter-item "><a href="../../too-many-lists/production-unsafe-deque/implementing-cursors.html"><strong aria-hidden="true">13.7.9.</strong> 实现游标</a></li><li class="chapter-item "><a href="../../too-many-lists/production-unsafe-deque/testing-cursors.html"><strong aria-hidden="true">13.7.10.</strong> 测试游标</a></li><li class="chapter-item "><a href="../../too-many-lists/production-unsafe-deque/final-code.html"><strong aria-hidden="true">13.7.11.</strong> 最终代码</a></li></ol></li><li class="chapter-item "><a href="../../too-many-lists/advanced-lists/intro.html"><strong aria-hidden="true">13.8.</strong> 使用高级技巧实现链表</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../too-many-lists/advanced-lists/double-singly.html"><strong aria-hidden="true">13.8.1.</strong> 双单向链表</a></li><li class="chapter-item "><a href="../../too-many-lists/advanced-lists/stack-allocated.html"><strong aria-hidden="true">13.8.2.</strong> 栈上的链表</a></li></ol></li></ol></li><li class="chapter-item "><li class="part-title">攻克编译错误</li><li class="spacer"></li><li class="chapter-item "><a href="../../compiler/intro.html"><strong aria-hidden="true">14.</strong> 征服编译错误</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../compiler/fight-with-compiler/intro.html"><strong aria-hidden="true">14.1.</strong> 对抗编译检查</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../compiler/fight-with-compiler/lifetime/intro.html"><strong aria-hidden="true">14.1.1.</strong> 生命周期</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../compiler/fight-with-compiler/lifetime/too-long1.html"><strong aria-hidden="true">14.1.1.1.</strong> 生命周期过大-01</a></li><li class="chapter-item "><a href="../../compiler/fight-with-compiler/lifetime/too-long2.html"><strong aria-hidden="true">14.1.1.2.</strong> 生命周期过大-02</a></li><li class="chapter-item "><a href="../../compiler/fight-with-compiler/lifetime/loop.html"><strong aria-hidden="true">14.1.1.3.</strong> 循环中的生命周期</a></li><li class="chapter-item "><a href="../../compiler/fight-with-compiler/lifetime/closure-with-static.html"><strong aria-hidden="true">14.1.1.4.</strong> 闭包碰到特征对象-01</a></li></ol></li><li class="chapter-item "><a href="../../compiler/fight-with-compiler/borrowing/intro.html"><strong aria-hidden="true">14.1.2.</strong> 重复借用</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../compiler/fight-with-compiler/borrowing/ref-exist-in-out-fn.html"><strong aria-hidden="true">14.1.2.1.</strong> 同时在函数内外使用引用</a></li><li class="chapter-item "><a href="../../compiler/fight-with-compiler/borrowing/borrow-distinct-fields-of-struct.html"><strong aria-hidden="true">14.1.2.2.</strong> 智能指针引起的重复借用错误</a></li></ol></li><li class="chapter-item "><a href="../../compiler/fight-with-compiler/unconstrained.html"><strong aria-hidden="true">14.1.3.</strong> 类型未限制(todo)</a></li><li class="chapter-item "><a href="../../compiler/fight-with-compiler/phantom-data.html"><strong aria-hidden="true">14.1.4.</strong> 幽灵数据(todo)</a></li></ol></li><li class="chapter-item "><a href="../../compiler/pitfalls/index.html"><strong aria-hidden="true">14.2.</strong> Rust 常见陷阱</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../compiler/pitfalls/use-vec-in-for.html"><strong aria-hidden="true">14.2.1.</strong> for 循环中使用外部数组</a></li><li class="chapter-item "><a href="../../compiler/pitfalls/stack-overflow.html"><strong aria-hidden="true">14.2.2.</strong> 线程类型导致的栈溢出</a></li><li class="chapter-item "><a href="../../compiler/pitfalls/arithmetic-overflow.html"><strong aria-hidden="true">14.2.3.</strong> 算术溢出导致的 panic</a></li><li class="chapter-item "><a href="../../compiler/pitfalls/closure-with-lifetime.html"><strong aria-hidden="true">14.2.4.</strong> 闭包中奇怪的生命周期</a></li><li class="chapter-item "><a href="../../compiler/pitfalls/the-disabled-mutability.html"><strong aria-hidden="true">14.2.5.</strong> 可变变量不可变？</a></li><li class="chapter-item "><a href="../../compiler/pitfalls/multiple-mutable-references.html"><strong aria-hidden="true">14.2.6.</strong> 可变借用失败引发的深入思考</a></li><li class="chapter-item "><a href="../../compiler/pitfalls/lazy-iterators.html"><strong aria-hidden="true">14.2.7.</strong> 不太勤快的迭代器</a></li><li class="chapter-item "><a href="../../compiler/pitfalls/weird-ranges.html"><strong aria-hidden="true">14.2.8.</strong> 奇怪的序列 x..y</a></li><li class="chapter-item "><a href="../../compiler/pitfalls/iterator-everywhere.html"><strong aria-hidden="true">14.2.9.</strong> 无处不在的迭代器</a></li><li class="chapter-item "><a href="../../compiler/pitfalls/main-with-channel-blocked.html"><strong aria-hidden="true">14.2.10.</strong> 线程间传递消息导致主线程无法结束</a></li><li class="chapter-item "><a href="../../compiler/pitfalls/utf8-performance.html"><strong aria-hidden="true">14.2.11.</strong> 警惕 UTF-8 引发的性能隐患</a></li></ol></li></ol></li><li class="chapter-item "><li class="part-title">性能优化</li><li class="spacer"></li><li class="chapter-item "><a href="../../profiling/intro.html"><strong aria-hidden="true">15.</strong> Rust 性能优化 todo</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../profiling/memory/intro.html"><strong aria-hidden="true">15.1.</strong> 深入内存 todo</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../profiling/memory/pointer-ref.html"><strong aria-hidden="true">15.1.1.</strong> 指针和引用 todo</a></li><li class="chapter-item "><a href="../../profiling/memory/uninit.html"><strong aria-hidden="true">15.1.2.</strong> 未初始化内存 todo</a></li><li class="chapter-item "><a href="../../profiling/memory/allocation.html"><strong aria-hidden="true">15.1.3.</strong> 内存分配 todo</a></li><li class="chapter-item "><a href="../../profiling/memory/layout.html"><strong aria-hidden="true">15.1.4.</strong> 内存布局 todo</a></li><li class="chapter-item "><a href="../../profiling/memory/virtual.html"><strong aria-hidden="true">15.1.5.</strong> 虚拟内存 todo</a></li></ol></li><li class="chapter-item "><a href="../../profiling/performance/intro.html"><strong aria-hidden="true">15.2.</strong> 性能调优 doing</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../profiling/performance/string.html"><strong aria-hidden="true">15.2.1.</strong> 字符串操作性能</a></li><li class="chapter-item "><a href="../../profiling/performance/deep-into-move.html"><strong aria-hidden="true">15.2.2.</strong> 深入理解 move</a></li><li class="chapter-item "><a href="../../profiling/performance/early-optimise.html"><strong aria-hidden="true">15.2.3.</strong> 糟糕的提前优化 todo</a></li><li class="chapter-item "><a href="../../profiling/performance/clone-copy.html"><strong aria-hidden="true">15.2.4.</strong> Clone 和 Copy todo</a></li><li class="chapter-item "><a href="../../profiling/performance/runtime-check.html"><strong aria-hidden="true">15.2.5.</strong> 减少 Runtime check(todo)</a></li><li class="chapter-item "><a href="../../profiling/performance/cpu-cache.html"><strong aria-hidden="true">15.2.6.</strong> CPU 缓存性能优化 todo</a></li><li class="chapter-item "><a href="../../profiling/performance/calculate.html"><strong aria-hidden="true">15.2.7.</strong> 计算性能优化 todo</a></li><li class="chapter-item "><a href="../../profiling/performance/heap-stack.html"><strong aria-hidden="true">15.2.8.</strong> 堆和栈 todo</a></li><li class="chapter-item "><a href="../../profiling/performance/allocator.html"><strong aria-hidden="true">15.2.9.</strong> 内存 allocator todo</a></li><li class="chapter-item "><a href="../../profiling/performance/tools.html"><strong aria-hidden="true">15.2.10.</strong> 常用性能测试工具 todo</a></li><li class="chapter-item "><a href="../../profiling/performance/enum.html"><strong aria-hidden="true">15.2.11.</strong> Enum 内存优化 todo</a></li></ol></li><li class="chapter-item "><a href="../../profiling/compiler/intro.html"><strong aria-hidden="true">15.3.</strong> 编译优化 todo</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../profiling/compiler/llvm.html"><strong aria-hidden="true">15.3.1.</strong> LLVM todo</a></li><li class="chapter-item "><a href="../../profiling/compiler/attributes.html"><strong aria-hidden="true">15.3.2.</strong> 常见属性标记 todo</a></li><li class="chapter-item "><a href="../../profiling/compiler/speed-up.html"><strong aria-hidden="true">15.3.3.</strong> 提升编译速度 todo</a></li><li class="chapter-item "><a href="../../profiling/compiler/optimization/intro.html"><strong aria-hidden="true">15.3.4.</strong> 编译器优化 todo</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../profiling/compiler/optimization/option.html"><strong aria-hidden="true">15.3.4.1.</strong> Option 枚举 todo</a></li></ol></li></ol></li></ol></li><li class="chapter-item "><li class="part-title">附录</li><li class="spacer"></li><li class="chapter-item "><div><strong aria-hidden="true">16.</strong> Appendix</div><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../appendix/keywords.html"><strong aria-hidden="true">16.1.</strong> 关键字</a></li><li class="chapter-item "><a href="../../appendix/operators.html"><strong aria-hidden="true">16.2.</strong> 运算符与符号</a></li><li class="chapter-item "><a href="../../appendix/expressions.html"><strong aria-hidden="true">16.3.</strong> 表达式</a></li><li class="chapter-item "><a href="../../appendix/derive.html"><strong aria-hidden="true">16.4.</strong> 派生特征 trait</a></li><li class="chapter-item "><a href="../../appendix/prelude.html"><strong aria-hidden="true">16.5.</strong> prelude 模块 todo</a></li><li class="chapter-item "><a href="../../appendix/rust-version.html"><strong aria-hidden="true">16.6.</strong> Rust 版本说明</a></li><li class="chapter-item "><a href="../../appendix/rust-versions/intro.html"><strong aria-hidden="true">16.7.</strong> Rust 历次版本更新解读</a><a class="toggle"><div>❱</div></a></li><li><ol class="section"><li class="chapter-item "><a href="../../appendix/rust-versions/1.58.html"><strong aria-hidden="true">16.7.1.</strong> 1.58</a></li><li class="chapter-item "><a href="../../appendix/rust-versions/1.59.html"><strong aria-hidden="true">16.7.2.</strong> 1.59</a></li><li class="chapter-item "><a href="../../appendix/rust-versions/1.60.html"><strong aria-hidden="true">16.7.3.</strong> 1.60</a></li><li class="chapter-item "><a href="../../appendix/rust-versions/1.61.html"><strong aria-hidden="true">16.7.4.</strong> 1.61</a></li><li class="chapter-item "><a href="../../appendix/rust-versions/1.62.html"><strong aria-hidden="true">16.7.5.</strong> 1.62</a></li><li class="chapter-item "><a href="../../appendix/rust-versions/1.63.html"><strong aria-hidden="true">16.7.6.</strong> 1.63</a></li><li class="chapter-item "><a href="../../appendix/rust-versions/1.64.html"><strong aria-hidden="true">16.7.7.</strong> 1.64</a></li><li class="chapter-item "><a href="../../appendix/rust-versions/1.65.html"><strong aria-hidden="true">16.7.8.</strong> 1.65</a></li><li class="chapter-item "><a href="../../appendix/rust-versions/1.66.html"><strong aria-hidden="true">16.7.9.</strong> 1.66</a></li><li class="chapter-item "><a href="../../appendix/rust-versions/1.67.html"><strong aria-hidden="true">16.7.10.</strong> 1.67</a></li><li class="chapter-item "><a href="../../appendix/rust-versions/1.68.html"><strong aria-hidden="true">16.7.11.</strong> 1.68</a></li><li class="chapter-item "><a href="../../appendix/rust-versions/1.69.html"><strong aria-hidden="true">16.7.12.</strong> 1.69</a></li><li class="chapter-item "><a href="../../appendix/rust-versions/1.70.html"><strong aria-hidden="true">16.7.13.</strong> 1.70</a></li><li class="chapter-item "><a href="../../appendix/rust-versions/1.71.html"><strong aria-hidden="true">16.7.14.</strong> 1.71</a></li><li class="chapter-item "><a href="../../appendix/rust-versions/1.72.html"><strong aria-hidden="true">16.7.15.</strong> 1.72</a></li><li class="chapter-item "><a href="../../appendix/rust-versions/1.73.html"><strong aria-hidden="true">16.7.16.</strong> 1.73</a></li><li class="chapter-item "><a href="../../appendix/rust-versions/1.74.html"><strong aria-hidden="true">16.7.17.</strong> 1.74</a></li><li class="chapter-item "><a href="../../appendix/rust-versions/1.75.html"><strong aria-hidden="true">16.7.18.</strong> 1.75</a></li><li class="chapter-item "><a href="../../appendix/rust-versions/1.76.html"><strong aria-hidden="true">16.7.19.</strong> 1.76</a></li><li class="chapter-item "><a href="../../appendix/rust-versions/1.77.html"><strong aria-hidden="true">16.7.20.</strong> 1.77</a></li><li class="chapter-item "><a href="../../appendix/rust-versions/1.78.html"><strong aria-hidden="true">16.7.21.</strong> 1.78</a></li><li class="chapter-item "><a href="../../appendix/rust-versions/1.79.html"><strong aria-hidden="true">16.7.22.</strong> 1.79</a></li><li class="chapter-item "><a href="../../appendix/rust-versions/1.80.html"><strong aria-hidden="true">16.7.23.</strong> 1.80</a></li><li class="chapter-item "><a href="../../appendix/rust-versions/1.81.html"><strong aria-hidden="true">16.7.24.</strong> 1.81</a></li><li class="chapter-item "><a href="../../appendix/rust-versions/1.82.html"><strong aria-hidden="true">16.7.25.</strong> 1.82</a></li></ol></li></ol></li></ol>
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<main>
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<h1 id="定海神针-pin-和-unpin"><a class="header" href="#定海神针-pin-和-unpin">定海神针 Pin 和 Unpin</a></h1>
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<p>在 Rust 异步编程中，有一个定海神针般的存在，它就是 <code>Pin</code>，作用说简单也简单，说复杂也非常复杂，当初刚出来时就连一些 Rust 大佬都一头雾水，何况瑟瑟发抖的我。好在今非昔比，目前网上的资料已经很全，而我就借花献佛，给大家好好讲讲这个 <code>Pin</code>。</p>
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<p>在 Rust 中，所有的类型可以分为两类:</p>
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<ul>
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<li><strong>类型的值可以在内存中安全地被移动</strong>，例如数值、字符串、布尔值、结构体、枚举，总之你能想到的几乎所有类型都可以落入到此范畴内</li>
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<li><strong>自引用类型</strong>，大魔王来了，大家快跑，在之前章节我们已经见识过它的厉害</li>
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</ul>
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<p>下面就是一个自引用类型</p>
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<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
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</span><span class="boring">fn main() {
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</span>struct SelfRef {
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value: String,
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pointer_to_value: *mut String,
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}
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<span class="boring">}</span></code></pre></pre>
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<p>在上面的结构体中，<code>pointer_to_value</code> 是一个裸指针，指向第一个字段 <code>value</code> 持有的字符串 <code>String</code> 。很简单对吧？现在考虑一个情况， 若 <code>value</code> 被移动了怎么办？</p>
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<p>此时一个致命的问题就出现了：<code>value</code> 的内存地址变了，而 <code>pointer_to_value</code> 依然指向 <code>value</code> 之前的地址，一个重大 bug 就出现了！</p>
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<p>灾难发生，英雄在哪？只见 <code>Pin</code> 闪亮登场，它可以防止一个类型在内存中被移动。再来回忆下之前在 <code>Future</code> 章节中，我们提到过在 <code>poll</code> 方法的签名中有一个 <code>self: Pin<&mut Self></code> ，那么为何要在这里使用 <code>Pin</code> 呢？</p>
|
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<h2 id="为何需要-pin"><a class="header" href="#为何需要-pin">为何需要 Pin</a></h2>
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<p>其实 <code>Pin</code> 还有一个小伙伴 <code>UnPin</code> ，与前者相反，后者表示类型可以在内存中安全地移动。在深入之前，我们先来回忆下 <code>async/.await</code> 是如何工作的:</p>
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<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
|
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</span><span class="boring">fn main() {
|
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</span>let fut_one = /* ... */; // Future 1
|
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let fut_two = /* ... */; // Future 2
|
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async move {
|
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fut_one.await;
|
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fut_two.await;
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}
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<span class="boring">}</span></code></pre></pre>
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<p>在底层，<code>async</code> 会创建一个实现了 <code>Future</code> 的匿名类型，并提供了一个 <code>poll</code> 方法：</p>
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<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
|
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</span><span class="boring">fn main() {
|
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</span>// `async { ... }`语句块创建的 `Future` 类型
|
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struct AsyncFuture {
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fut_one: FutOne,
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fut_two: FutTwo,
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state: State,
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}
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// `async` 语句块可能处于的状态
|
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enum State {
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AwaitingFutOne,
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AwaitingFutTwo,
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Done,
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}
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impl Future for AsyncFuture {
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type Output = ();
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|
fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<()> {
|
|
|
loop {
|
|
|
match self.state {
|
|
|
State::AwaitingFutOne => match self.fut_one.poll(..) {
|
|
|
Poll::Ready(()) => self.state = State::AwaitingFutTwo,
|
|
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Poll::Pending => return Poll::Pending,
|
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}
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|
|
State::AwaitingFutTwo => match self.fut_two.poll(..) {
|
|
|
Poll::Ready(()) => self.state = State::Done,
|
|
|
Poll::Pending => return Poll::Pending,
|
|
|
}
|
|
|
State::Done => return Poll::Ready(()),
|
|
|
}
|
|
|
}
|
|
|
}
|
|
|
}
|
|
|
<span class="boring">}</span></code></pre></pre>
|
|
|
<p>当 <code>poll</code> 第一次被调用时，它会去查询 <code>fut_one</code> 的状态，若 <code>fut_one</code> 无法完成，则 <code>poll</code> 方法会返回。未来对 <code>poll</code> 的调用将从上一次调用结束的地方开始。该过程会一直持续，直到 <code>Future</code> 完成为止。</p>
|
|
|
<p>然而，如果我们的 <code>async</code> 语句块中使用了引用类型，会发生什么？例如下面例子：</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
|
|
|
</span><span class="boring">fn main() {
|
|
|
</span>async {
|
|
|
let mut x = [0; 128];
|
|
|
let read_into_buf_fut = read_into_buf(&mut x);
|
|
|
read_into_buf_fut.await;
|
|
|
println!("{:?}", x);
|
|
|
}
|
|
|
<span class="boring">}</span></code></pre></pre>
|
|
|
<p>这段代码会编译成下面的形式：</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
|
|
|
</span><span class="boring">fn main() {
|
|
|
</span>struct ReadIntoBuf<'a> {
|
|
|
buf: &'a mut [u8], // 指向下面的`x`字段
|
|
|
}
|
|
|
|
|
|
struct AsyncFuture {
|
|
|
x: [u8; 128],
|
|
|
read_into_buf_fut: ReadIntoBuf<'what_lifetime?>,
|
|
|
}
|
|
|
<span class="boring">}</span></code></pre></pre>
|
|
|
<p>这里，<code>ReadIntoBuf</code> 拥有一个引用字段，指向了结构体的另一个字段 <code>x</code> ，一旦 <code>AsyncFuture</code> 被移动，那 <code>x</code> 的地址也将随之变化，此时对 <code>x</code> 的引用就变成了不合法的，也就是 <code>read_into_buf_fut.buf</code> 会变为不合法的。</p>
|
|
|
<p>若能将 <code>Future</code> 在内存中固定到一个位置，就可以避免这种问题的发生，也就可以安全的创建上面这种引用类型。</p>
|
|
|
<h2 id="unpin"><a class="header" href="#unpin">Unpin</a></h2>
|
|
|
<p>事实上，绝大多数类型都不在意是否被移动(开篇提到的第一种类型)，因此它们都<strong>自动实现</strong>了 <code>Unpin</code> 特征。</p>
|
|
|
<p>从名字推测，大家可能以为 <code>Pin</code> 和 <code>Unpin</code> 都是特征吧？实际上，<code>Pin</code> 不按套路出牌，它是一个结构体：</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
|
|
|
</span><span class="boring">fn main() {
|
|
|
</span>pub struct Pin<P> {
|
|
|
pointer: P,
|
|
|
}
|
|
|
<span class="boring">}</span></code></pre></pre>
|
|
|
<p>它包裹一个指针，并且能确保该指针指向的数据不会被移动，例如 <code>Pin<&mut T></code> , <code>Pin<&T></code> , <code>Pin<Box<T>></code> ，都能确保 <code>T</code> 不会被移动。</p>
|
|
|
<img alt="" src="https://pic1.zhimg.com/80/v2-de79f3a7a401588d671ecd121916cd90_1440w.png" class="center" />
|
|
|
<p>而 <code>Unpin</code> 才是一个特征，它表明一个类型可以随意被移动，那么问题来了，可以被 <code>Pin</code> 住的值，它有没有实现什么特征呢？ 答案很出乎意料，可以被 <code>Pin</code> 住的值实现的特征是 <code>!Unpin</code> ，大家可能之前没有见过，但是它其实很简单，<code>!</code> 代表没有实现某个特征的意思，<code>!Unpin</code> 说明类型没有实现 <code>Unpin</code> 特征，那自然就可以被 <code>Pin</code> 了。</p>
|
|
|
<p>那是不是意味着类型如果实现了 <code>Unpin</code> 特征，就不能被 <code>Pin</code> 了？其实，还是可以 <code>Pin</code> 的，毕竟它只是一个结构体，你可以随意使用，<strong>但是不再有任何效果而已，该值一样可以被移动</strong>！</p>
|
|
|
<p>例如 <code>Pin<&mut u8></code> ，显然 <code>u8</code> 实现了 <code>Unpin</code> 特征，它可以在内存中被移动，因此 <code>Pin<&mut u8></code> 跟 <code>&mut u8</code> 实际上并无区别，一样可以被移动。</p>
|
|
|
<p>因此，一个类型如果不能被移动，它必须实现 <code>!Unpin</code> 特征。如果大家对 <code>Pin</code> 、 <code>Unpin</code> 还是模模糊糊，建议再重复看一遍之前的内容，理解它们对于我们后面要讲到的内容非常重要！</p>
|
|
|
<p>如果将 <code>Unpin</code> 与之前章节学过的 <a href="https://course.rs/advance/concurrency-with-threads/send-sync.html"><code>Send/Sync</code></a> 进行下对比，会发现它们都很像：</p>
|
|
|
<ul>
|
|
|
<li>都是标记特征( marker trait )，该特征未定义任何行为，非常适用于标记</li>
|
|
|
<li>都可以通过<code>!</code>语法去除实现</li>
|
|
|
<li>绝大多数情况都是自动实现, 无需我们的操心</li>
|
|
|
</ul>
|
|
|
<h2 id="深入理解-pin"><a class="header" href="#深入理解-pin">深入理解 Pin</a></h2>
|
|
|
<p>对于上面的问题，我们可以简单的归结为如何在 Rust 中处理自引用类型(果然，只要是难点，都和自引用脱离不了关系)，下面用一个稍微简单点的例子来理解下 <code>Pin</code> :</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
|
|
|
</span><span class="boring">fn main() {
|
|
|
</span>#[derive(Debug)]
|
|
|
struct Test {
|
|
|
a: String,
|
|
|
b: *const String,
|
|
|
}
|
|
|
|
|
|
impl Test {
|
|
|
fn new(txt: &str) -> Self {
|
|
|
Test {
|
|
|
a: String::from(txt),
|
|
|
b: std::ptr::null(),
|
|
|
}
|
|
|
}
|
|
|
|
|
|
fn init(&mut self) {
|
|
|
let self_ref: *const String = &self.a;
|
|
|
self.b = self_ref;
|
|
|
}
|
|
|
|
|
|
fn a(&self) -> &str {
|
|
|
&self.a
|
|
|
}
|
|
|
|
|
|
fn b(&self) -> &String {
|
|
|
assert!(!self.b.is_null(), "Test::b called without Test::init being called first");
|
|
|
unsafe { &*(self.b) }
|
|
|
}
|
|
|
}
|
|
|
<span class="boring">}</span></code></pre></pre>
|
|
|
<p><code>Test</code> 提供了方法用于获取字段 <code>a</code> 和 <code>b</code> 的值的引用。这里<code>b</code> 是 <code>a</code> 的一个引用，但是我们并没有使用引用类型而是用了裸指针，原因是：Rust 的借用规则不允许我们这样用，因为不符合生命周期的要求。 此时的 <code>Test</code> 就是一个自引用结构体。</p>
|
|
|
<p>如果不移动任何值，那么上面的例子将没有任何问题，例如:</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021">fn main() {
|
|
|
let mut test1 = Test::new("test1");
|
|
|
test1.init();
|
|
|
let mut test2 = Test::new("test2");
|
|
|
test2.init();
|
|
|
|
|
|
println!("a: {}, b: {}", test1.a(), test1.b());
|
|
|
println!("a: {}, b: {}", test2.a(), test2.b());
|
|
|
|
|
|
}</code></pre></pre>
|
|
|
<p>输出非常正常：</p>
|
|
|
<pre><code class="language-console">a: test1, b: test1
|
|
|
a: test2, b: test2
|
|
|
</code></pre>
|
|
|
<p>明知山有虎，偏向虎山行，这才是我辈年轻人的风华。既然移动数据会导致指针不合法，那我们就移动下数据试试，将 <code>test1</code> 和 <code>test2</code> 进行下交换：</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021">fn main() {
|
|
|
let mut test1 = Test::new("test1");
|
|
|
test1.init();
|
|
|
let mut test2 = Test::new("test2");
|
|
|
test2.init();
|
|
|
|
|
|
println!("a: {}, b: {}", test1.a(), test1.b());
|
|
|
std::mem::swap(&mut test1, &mut test2);
|
|
|
println!("a: {}, b: {}", test2.a(), test2.b());
|
|
|
|
|
|
}</code></pre></pre>
|
|
|
<p>按理来说，这样修改后，输出应该如下:</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
|
|
|
</span><span class="boring">fn main() {
|
|
|
</span>a: test1, b: test1
|
|
|
a: test1, b: test1
|
|
|
<span class="boring">}</span></code></pre></pre>
|
|
|
<p>但是实际运行后，却产生了下面的输出:</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
|
|
|
</span><span class="boring">fn main() {
|
|
|
</span>a: test1, b: test1
|
|
|
a: test1, b: test2
|
|
|
<span class="boring">}</span></code></pre></pre>
|
|
|
<p>原因是 <code>test2.b</code> 指针依然指向了旧的地址，而该地址对应的值现在在 <code>test1</code> 里，最终会打印出意料之外的值。</p>
|
|
|
<p>如果大家还是将信将疑，那再看看下面的代码：</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021">fn main() {
|
|
|
let mut test1 = Test::new("test1");
|
|
|
test1.init();
|
|
|
let mut test2 = Test::new("test2");
|
|
|
test2.init();
|
|
|
|
|
|
println!("a: {}, b: {}", test1.a(), test1.b());
|
|
|
std::mem::swap(&mut test1, &mut test2);
|
|
|
test1.a = "I've totally changed now!".to_string();
|
|
|
println!("a: {}, b: {}", test2.a(), test2.b());
|
|
|
|
|
|
}</code></pre></pre>
|
|
|
<p>下面的图片也可以帮助更好的理解这个过程：</p>
|
|
|
<img alt="" src="https://pica.zhimg.com/80/v2-eaeb33da283dc1063b862d2307821976_1440w.jpg" class="center" />
|
|
|
<h2 id="pin-在实践中的运用"><a class="header" href="#pin-在实践中的运用">Pin 在实践中的运用</a></h2>
|
|
|
<p>在理解了 <code>Pin</code> 的作用后，我们再来看看它怎么帮我们解决问题。</p>
|
|
|
<h4 id="将值固定到栈上"><a class="header" href="#将值固定到栈上">将值固定到栈上</a></h4>
|
|
|
<p>回到之前的例子，我们可以用 <code>Pin</code> 来解决指针指向的数据被移动的问题:</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
|
|
|
</span><span class="boring">fn main() {
|
|
|
</span>use std::pin::Pin;
|
|
|
use std::marker::PhantomPinned;
|
|
|
|
|
|
#[derive(Debug)]
|
|
|
struct Test {
|
|
|
a: String,
|
|
|
b: *const String,
|
|
|
_marker: PhantomPinned,
|
|
|
}
|
|
|
|
|
|
|
|
|
impl Test {
|
|
|
fn new(txt: &str) -> Self {
|
|
|
Test {
|
|
|
a: String::from(txt),
|
|
|
b: std::ptr::null(),
|
|
|
_marker: PhantomPinned, // 这个标记可以让我们的类型自动实现特征`!Unpin`
|
|
|
}
|
|
|
}
|
|
|
|
|
|
fn init(self: Pin<&mut Self>) {
|
|
|
let self_ptr: *const String = &self.a;
|
|
|
let this = unsafe { self.get_unchecked_mut() };
|
|
|
this.b = self_ptr;
|
|
|
}
|
|
|
|
|
|
fn a(self: Pin<&Self>) -> &str {
|
|
|
&self.get_ref().a
|
|
|
}
|
|
|
|
|
|
fn b(self: Pin<&Self>) -> &String {
|
|
|
assert!(!self.b.is_null(), "Test::b called without Test::init being called first");
|
|
|
unsafe { &*(self.b) }
|
|
|
}
|
|
|
}
|
|
|
<span class="boring">}</span></code></pre></pre>
|
|
|
<p>上面代码中，我们使用了一个标记类型 <code>PhantomPinned</code> 将自定义结构体 <code>Test</code> 变成了 <code>!Unpin</code> (编译器会自动帮我们实现)，因此该结构体无法再被移动。</p>
|
|
|
<p>一旦类型实现了 <code>!Unpin</code> ，那将它的值固定到栈( <code>stack</code> )上就是不安全的行为，因此在代码中我们使用了 <code>unsafe</code> 语句块来进行处理，你也可以使用 <a href="https://docs.rs/pin-utils/"><code>pin_utils</code></a> 来避免 <code>unsafe</code> 的使用。</p>
|
|
|
<blockquote>
|
|
|
<p>BTW, Rust 中的 unsafe 其实没有那么可怕，虽然听上去很不安全，但是实际上 Rust 依然提供了很多机制来帮我们提升了安全性，因此不必像对待 Go 语言的 <code>unsafe</code> 那样去畏惧于使用 Rust 中的 <code>unsafe</code> ，大致使用原则总结如下：没必要用时，就不要用，当有必要用时，就大胆用，但是尽量控制好边界，让 <code>unsafe</code> 的范围尽可能小</p>
|
|
|
</blockquote>
|
|
|
<p>此时，再去尝试移动被固定的值，就会导致<strong>编译错误</strong>：</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021">pub fn main() {
|
|
|
// 此时的`test1`可以被安全的移动
|
|
|
let mut test1 = Test::new("test1");
|
|
|
// 新的`test1`由于使用了`Pin`，因此无法再被移动，这里的声明会将之前的`test1`遮蔽掉(shadow)
|
|
|
let mut test1 = unsafe { Pin::new_unchecked(&mut test1) };
|
|
|
Test::init(test1.as_mut());
|
|
|
|
|
|
let mut test2 = Test::new("test2");
|
|
|
let mut test2 = unsafe { Pin::new_unchecked(&mut test2) };
|
|
|
Test::init(test2.as_mut());
|
|
|
|
|
|
println!("a: {}, b: {}", Test::a(test1.as_ref()), Test::b(test1.as_ref()));
|
|
|
std::mem::swap(test1.get_mut(), test2.get_mut());
|
|
|
println!("a: {}, b: {}", Test::a(test2.as_ref()), Test::b(test2.as_ref()));
|
|
|
}</code></pre></pre>
|
|
|
<p>注意到之前的粗体字了吗？是的，Rust 并不是在运行时做这件事，而是在编译期就完成了，因此没有额外的性能开销！来看看报错:</p>
|
|
|
<pre><code class="language-shell">error[E0277]: `PhantomPinned` cannot be unpinned
|
|
|
--> src/main.rs:47:43
|
|
|
|
|
|
|
47 | std::mem::swap(test1.get_mut(), test2.get_mut());
|
|
|
| ^^^^^^^ within `Test`, the trait `Unpin` is not implemented for `PhantomPinned`
|
|
|
</code></pre>
|
|
|
<blockquote>
|
|
|
<p>需要注意的是固定在栈上非常依赖于你写出的 <code>unsafe</code> 代码的正确性。我们知道 <code>&'a mut T</code> 可以固定的生命周期是 <code>'a</code> ，但是我们却不知道当生命周期 <code>'a</code> 结束后，该指针指向的数据是否会被移走。如果你的 <code>unsafe</code> 代码里这么实现了，那么就会违背 <code>Pin</code> 应该具有的作用！</p>
|
|
|
<p>一个常见的错误就是忘记去<a href="https://course.rs/basic/variable.html#%E5%8F%98%E9%87%8F%E9%81%AE%E8%94%BDshadowing">遮蔽( shadow )</a>初始的变量，因为你可以 <code>drop</code> 掉 <code>Pin</code> ，然后在 <code>&'a mut T</code> 结束后去移动数据:</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021">fn main() {
|
|
|
let mut test1 = Test::new("test1");
|
|
|
let mut test1_pin = unsafe { Pin::new_unchecked(&mut test1) };
|
|
|
Test::init(test1_pin.as_mut());
|
|
|
|
|
|
drop(test1_pin);
|
|
|
println!(r#"test1.b points to "test1": {:?}..."#, test1.b);
|
|
|
|
|
|
let mut test2 = Test::new("test2");
|
|
|
mem::swap(&mut test1, &mut test2);
|
|
|
println!("... and now it points nowhere: {:?}", test1.b);
|
|
|
}
|
|
|
<span class="boring">use std::pin::Pin;
|
|
|
</span><span class="boring">use std::marker::PhantomPinned;
|
|
|
</span><span class="boring">use std::mem;
|
|
|
</span><span class="boring">
|
|
|
</span><span class="boring">#[derive(Debug)]
|
|
|
</span><span class="boring">struct Test {
|
|
|
</span><span class="boring"> a: String,
|
|
|
</span><span class="boring"> b: *const String,
|
|
|
</span><span class="boring"> _marker: PhantomPinned,
|
|
|
</span><span class="boring">}
|
|
|
</span><span class="boring">
|
|
|
</span><span class="boring">
|
|
|
</span><span class="boring">impl Test {
|
|
|
</span><span class="boring"> fn new(txt: &str) -> Self {
|
|
|
</span><span class="boring"> Test {
|
|
|
</span><span class="boring"> a: String::from(txt),
|
|
|
</span><span class="boring"> b: std::ptr::null(),
|
|
|
</span><span class="boring"> // This makes our type `!Unpin`
|
|
|
</span><span class="boring"> _marker: PhantomPinned,
|
|
|
</span><span class="boring"> }
|
|
|
</span><span class="boring"> }
|
|
|
</span><span class="boring">
|
|
|
</span><span class="boring"> fn init<'a>(self: Pin<&'a mut Self>) {
|
|
|
</span><span class="boring"> let self_ptr: *const String = &self.a;
|
|
|
</span><span class="boring"> let this = unsafe { self.get_unchecked_mut() };
|
|
|
</span><span class="boring"> this.b = self_ptr;
|
|
|
</span><span class="boring"> }
|
|
|
</span><span class="boring">
|
|
|
</span><span class="boring"> fn a<'a>(self: Pin<&'a Self>) -> &'a str {
|
|
|
</span><span class="boring"> &self.get_ref().a
|
|
|
</span><span class="boring"> }
|
|
|
</span><span class="boring">
|
|
|
</span><span class="boring"> fn b<'a>(self: Pin<&'a Self>) -> &'a String {
|
|
|
</span><span class="boring"> assert!(!self.b.is_null(), "Test::b called without Test::init being called first");
|
|
|
</span><span class="boring"> unsafe { &*(self.b) }
|
|
|
</span><span class="boring"> }
|
|
|
</span><span class="boring">}</span></code></pre></pre>
|
|
|
</blockquote>
|
|
|
<h4 id="固定到堆上"><a class="header" href="#固定到堆上">固定到堆上</a></h4>
|
|
|
<p>将一个 <code>!Unpin</code> 类型的值固定到堆上，会给予该值一个稳定的内存地址，它指向的堆中的值在 <code>Pin</code> 后是无法被移动的。而且与固定在栈上不同，我们知道堆上的值在整个生命周期内都会被稳稳地固定住。</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021">use std::pin::Pin;
|
|
|
use std::marker::PhantomPinned;
|
|
|
|
|
|
#[derive(Debug)]
|
|
|
struct Test {
|
|
|
a: String,
|
|
|
b: *const String,
|
|
|
_marker: PhantomPinned,
|
|
|
}
|
|
|
|
|
|
impl Test {
|
|
|
fn new(txt: &str) -> Pin<Box<Self>> {
|
|
|
let t = Test {
|
|
|
a: String::from(txt),
|
|
|
b: std::ptr::null(),
|
|
|
_marker: PhantomPinned,
|
|
|
};
|
|
|
let mut boxed = Box::pin(t);
|
|
|
let self_ptr: *const String = &boxed.as_ref().a;
|
|
|
unsafe { boxed.as_mut().get_unchecked_mut().b = self_ptr };
|
|
|
|
|
|
boxed
|
|
|
}
|
|
|
|
|
|
fn a(self: Pin<&Self>) -> &str {
|
|
|
&self.get_ref().a
|
|
|
}
|
|
|
|
|
|
fn b(self: Pin<&Self>) -> &String {
|
|
|
unsafe { &*(self.b) }
|
|
|
}
|
|
|
}
|
|
|
|
|
|
pub fn main() {
|
|
|
let test1 = Test::new("test1");
|
|
|
let test2 = Test::new("test2");
|
|
|
|
|
|
println!("a: {}, b: {}",test1.as_ref().a(), test1.as_ref().b());
|
|
|
println!("a: {}, b: {}",test2.as_ref().a(), test2.as_ref().b());
|
|
|
}</code></pre></pre>
|
|
|
<h4 id="将固定住的-future-变为-unpin"><a class="header" href="#将固定住的-future-变为-unpin">将固定住的 <code>Future</code> 变为 <code>Unpin</code></a></h4>
|
|
|
<p>之前的章节我们有提到 <code>async</code> 函数返回的 <code>Future</code> 默认就是 <code>!Unpin</code> 的。</p>
|
|
|
<p>但是，在实际应用中，一些函数会要求它们处理的 <code>Future</code> 是 <code>Unpin</code> 的，此时，若你使用的 <code>Future</code> 是 <code>!Unpin</code> 的，必须要使用以下的方法先将 <code>Future</code> 进行固定:</p>
|
|
|
<ul>
|
|
|
<li><code>Box::pin</code>， 创建一个 <code>Pin<Box<T>></code></li>
|
|
|
<li><code>pin_utils::pin_mut!</code>， 创建一个 <code>Pin<&mut T></code></li>
|
|
|
</ul>
|
|
|
<p>固定后获得的 <code>Pin<Box<T>></code> 和 <code>Pin<&mut T></code> 既可以用于 <code>Future</code> ，<strong>又会自动实现 <code>Unpin</code></strong>。</p>
|
|
|
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
|
|
|
</span><span class="boring">fn main() {
|
|
|
</span>use pin_utils::pin_mut; // `pin_utils` 可以在crates.io中找到
|
|
|
|
|
|
// 函数的参数是一个`Future`，但是要求该`Future`实现`Unpin`
|
|
|
fn execute_unpin_future(x: impl Future<Output = ()> + Unpin) { /* ... */ }
|
|
|
|
|
|
let fut = async { /* ... */ };
|
|
|
// 下面代码报错: 默认情况下，`fut` 实现的是`!Unpin`，并没有实现`Unpin`
|
|
|
// execute_unpin_future(fut);
|
|
|
|
|
|
// 使用`Box`进行固定
|
|
|
let fut = async { /* ... */ };
|
|
|
let fut = Box::pin(fut);
|
|
|
execute_unpin_future(fut); // OK
|
|
|
|
|
|
// 使用`pin_mut!`进行固定
|
|
|
let fut = async { /* ... */ };
|
|
|
pin_mut!(fut);
|
|
|
execute_unpin_future(fut); // OK
|
|
|
<span class="boring">}</span></code></pre></pre>
|
|
|
<h2 id="总结"><a class="header" href="#总结">总结</a></h2>
|
|
|
<p>相信大家看到这里，脑袋里已经快被 <code>Pin</code> 、 <code>Unpin</code> 、 <code>!Unpin</code> 整爆炸了，没事，我们再来火上浇油下:)</p>
|
|
|
<ul>
|
|
|
<li>若 <code>T: Unpin</code> ( Rust 类型的默认实现)，那么 <code>Pin<'a, T></code> 跟 <code>&'a mut T</code> 完全相同，也就是 <code>Pin</code> 将没有任何效果, 该移动还是照常移动</li>
|
|
|
<li>绝大多数标准库类型都实现了 <code>Unpin</code> ，事实上，对于 Rust 中你能遇到的绝大多数类型，该结论依然成立
|
|
|
，其中一个例外就是：<code>async/await</code> 生成的 <code>Future</code> 没有实现 <code>Unpin</code></li>
|
|
|
<li>你可以通过以下方法为自己的类型添加 <code>!Unpin</code> 约束：
|
|
|
<ul>
|
|
|
<li>使用文中提到的 <code>std::marker::PhantomPinned</code></li>
|
|
|
<li>使用<code>nightly</code> 版本下的 <code>feature flag</code></li>
|
|
|
</ul>
|
|
|
</li>
|
|
|
<li>可以将值固定到栈上，也可以固定到堆上
|
|
|
<ul>
|
|
|
<li>将 <code>!Unpin</code> 值固定到栈上需要使用 <code>unsafe</code></li>
|
|
|
<li>将 <code>!Unpin</code> 值固定到堆上无需 <code>unsafe</code> ，可以通过 <code>Box::pin</code> 来简单的实现</li>
|
|
|
</ul>
|
|
|
</li>
|
|
|
<li>当固定类型 <code>T: !Unpin</code> 时，你需要保证数据从被固定到被 drop 这段时期内，其内存不会变得非法或者被重用</li>
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