294 lines
16 KiB
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294 lines
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<ol class="chapter"><li class="affix"><a href="introduction.html" class="active">Introduction</a></li><li><a href="0_background_information.html"><strong aria-hidden="true">1.</strong> Background information</a></li><li><a href="1_futures_in_rust.html"><strong aria-hidden="true">2.</strong> Futures in Rust</a></li><li><a href="2_waker_context.html"><strong aria-hidden="true">3.</strong> Waker and Context</a></li><li><a href="3_generators_pin.html"><strong aria-hidden="true">4.</strong> Generators</a></li><li><a href="4_pin.html"><strong aria-hidden="true">5.</strong> Pin</a></li><li><a href="6_future_example.html"><strong aria-hidden="true">6.</strong> Futures - our main example</a></li><li><a href="8_finished_example.html"><strong aria-hidden="true">7.</strong> Finished example (editable)</a></li><li class="affix"><a href="conclusion.html">Conclusion and exercises</a></li></ol>
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<h1 class="menu-title">Futures Explained in 200 Lines of Rust</h1>
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<main>
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<h1><a class="header" href="#futures-explained-in-200-lines-of-rust" id="futures-explained-in-200-lines-of-rust">Futures Explained in 200 Lines of Rust</a></h1>
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<p>This book aims to explain <code>Futures</code> in Rust using an example driven approach,
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exploring why they're designed the way they are, the alternatives and how
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they work.</p>
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<p>Going into the level of detail I do in this book is not needed to use futures
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or async/await in Rust. It's for the curious out there that want to know <em>how</em>
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it all works.</p>
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<h2><a class="header" href="#what-this-book-covers" id="what-this-book-covers">What this book covers</a></h2>
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<p>This book will try to explain everything you might wonder about up until the
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topic of different types of executors and runtimes. We'll just implement a very
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simple runtime in this book introducing some concepts but it's enough to get
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started.</p>
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<p><a href="https://github.com/stjepang">Stjepan Glavina</a> has made an excellent series of
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articles about async runtimes and executors, and if the rumors are right he's
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even working on a new async runtime that should be easy enough to use as
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learning material.</p>
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<p>The way you should go about it is to read this book first, then continue
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reading the <a href="https://stjepang.github.io/">articles from stejpang</a> to learn more
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about runtimes and how they work, especially:</p>
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<ol>
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<li><a href="https://stjepang.github.io/2020/01/25/build-your-own-block-on.html">Build your own block_on()</a></li>
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<li><a href="https://stjepang.github.io/2020/01/31/build-your-own-executor.html">Build your own executor</a></li>
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</ol>
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<p>I've limited myself to a 200 line main example (hence the title) to limit the
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scope and introduce an example that can easily be explored further.</p>
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<p>However, there is a lot to digest and it's not what I would call easy, but we'll
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take everything step by step so get a cup of tea and relax. </p>
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<p>I hope you enjoy the ride.</p>
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<blockquote>
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<p>This book is developed in the open, and contributions are welcome. You'll find
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<a href="https://github.com/cfsamson/books-futures-explained">the repository for the book itself here</a>. The final example which
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you can clone, fork or copy <a href="https://github.com/cfsamson/examples-futures">can be found here</a>. Any suggestions
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or improvements can be filed as a PR or in the issue tracker for the book.</p>
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</blockquote>
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<h2><a class="header" href="#reader-exercises-and-further-reading" id="reader-exercises-and-further-reading">Reader exercises and further reading</a></h2>
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<p>In the last <a href="conclusion.html">chapter</a> I've taken the liberty to suggest some
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small exercises if you want to explore a little further.</p>
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<p>This book is also the fourth book I have written about concurrent programming
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in Rust. If you like it, you might want to check out the others as well:</p>
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<ul>
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<li><a href="https://cfsamson.gitbook.io/green-threads-explained-in-200-lines-of-rust/">Green Threads Explained in 200 lines of rust</a></li>
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<li><a href="https://cfsamson.github.io/book-exploring-async-basics/">The Node Experiment - Exploring Async Basics with Rust</a></li>
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<li><a href="https://cfsamsonbooks.gitbook.io/epoll-kqueue-iocp-explained/">Epoll, Kqueue and IOCP Explained with Rust</a></li>
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</ul>
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<h2><a class="header" href="#credits-and-thanks" id="credits-and-thanks">Credits and thanks</a></h2>
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<p>I'll like to take the chance of thanking the people behind <code>mio</code>, <code>tokio</code>,
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<code>async_std</code>, <code>Futures</code>, <code>libc</code>, <code>crossbeam</code> and many other libraries which so
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much is built upon.</p>
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<p>A special thanks to <a href="https://github.com/jonhoo">Johnhoo</a> who was kind enough to
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give me some feedback on an early draft of this book. He has not read the
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finished product and has in no way endorsed it, but a thanks is definitely due.</p>
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