introduction draft
This commit is contained in:
Carl Fredrik Samson
501
book/0_2_naive_implementation.html
Normal file
501
book/0_2_naive_implementation.html
Normal file
@@ -0,0 +1,501 @@
|
||||
<!DOCTYPE HTML>
|
||||
<html lang="en" class="sidebar-visible no-js light">
|
||||
<head>
|
||||
<!-- Book generated using mdBook -->
|
||||
<meta charset="UTF-8">
|
||||
<title>Naive example - Futures Explained in 200 Lines of Rust</title>
|
||||
|
||||
|
||||
<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
|
||||
<meta name="description" content="">
|
||||
<meta name="viewport" content="width=device-width, initial-scale=1">
|
||||
<meta name="theme-color" content="#ffffff" />
|
||||
|
||||
<link rel="shortcut icon" href="favicon.png">
|
||||
<link rel="stylesheet" href="css/variables.css">
|
||||
<link rel="stylesheet" href="css/general.css">
|
||||
<link rel="stylesheet" href="css/chrome.css">
|
||||
<link rel="stylesheet" href="css/print.css" media="print">
|
||||
|
||||
<!-- Fonts -->
|
||||
<link rel="stylesheet" href="FontAwesome/css/font-awesome.css">
|
||||
<link href="https://fonts.googleapis.com/css?family=Open+Sans:300italic,400italic,600italic,700italic,800italic,400,300,600,700,800" rel="stylesheet" type="text/css">
|
||||
<link href="https://fonts.googleapis.com/css?family=Source+Code+Pro:500" rel="stylesheet" type="text/css">
|
||||
|
||||
<!-- Highlight.js Stylesheets -->
|
||||
<link rel="stylesheet" href="highlight.css">
|
||||
<link rel="stylesheet" href="tomorrow-night.css">
|
||||
<link rel="stylesheet" href="ayu-highlight.css">
|
||||
|
||||
<!-- Custom theme stylesheets -->
|
||||
|
||||
|
||||
|
||||
</head>
|
||||
<body>
|
||||
<!-- Provide site root to javascript -->
|
||||
<script type="text/javascript">
|
||||
var path_to_root = "";
|
||||
var default_theme = window.matchMedia("(prefers-color-scheme: dark)").matches ? "light" : "light";
|
||||
</script>
|
||||
|
||||
<!-- Work around some values being stored in localStorage wrapped in quotes -->
|
||||
<script type="text/javascript">
|
||||
try {
|
||||
var theme = localStorage.getItem('mdbook-theme');
|
||||
var sidebar = localStorage.getItem('mdbook-sidebar');
|
||||
|
||||
if (theme.startsWith('"') && theme.endsWith('"')) {
|
||||
localStorage.setItem('mdbook-theme', theme.slice(1, theme.length - 1));
|
||||
}
|
||||
|
||||
if (sidebar.startsWith('"') && sidebar.endsWith('"')) {
|
||||
localStorage.setItem('mdbook-sidebar', sidebar.slice(1, sidebar.length - 1));
|
||||
}
|
||||
} catch (e) { }
|
||||
</script>
|
||||
|
||||
<!-- Set the theme before any content is loaded, prevents flash -->
|
||||
<script type="text/javascript">
|
||||
var theme;
|
||||
try { theme = localStorage.getItem('mdbook-theme'); } catch(e) { }
|
||||
if (theme === null || theme === undefined) { theme = default_theme; }
|
||||
var html = document.querySelector('html');
|
||||
html.classList.remove('no-js')
|
||||
html.classList.remove('light')
|
||||
html.classList.add(theme);
|
||||
html.classList.add('js');
|
||||
</script>
|
||||
|
||||
<!-- Hide / unhide sidebar before it is displayed -->
|
||||
<script type="text/javascript">
|
||||
var html = document.querySelector('html');
|
||||
var sidebar = 'hidden';
|
||||
if (document.body.clientWidth >= 1080) {
|
||||
try { sidebar = localStorage.getItem('mdbook-sidebar'); } catch(e) { }
|
||||
sidebar = sidebar || 'visible';
|
||||
}
|
||||
html.classList.remove('sidebar-visible');
|
||||
html.classList.add("sidebar-" + sidebar);
|
||||
</script>
|
||||
|
||||
<nav id="sidebar" class="sidebar" aria-label="Table of contents">
|
||||
<div id="sidebar-scrollbox" class="sidebar-scrollbox">
|
||||
<ol class="chapter"><li class="expanded "><a href="0_0_introduction.html"><strong aria-hidden="true">1.</strong> Introduction</a></li><li class="expanded "><a href="0_1_background_information.html"><strong aria-hidden="true">2.</strong> Some background information</a></li><li class="expanded "><a href="0_2_naive_implementation.html" class="active"><strong aria-hidden="true">3.</strong> Naive example</a></li><li class="expanded "><a href="0_3_proper_waker.html"><strong aria-hidden="true">4.</strong> Proper Waker</a></li><li class="expanded "><a href="0_4_proper_future.html"><strong aria-hidden="true">5.</strong> Proper Future</a></li><li class="expanded "><a href="0_5_async_wait.html"><strong aria-hidden="true">6.</strong> Supporting async/await</a></li><li class="expanded "><a href="0_6_concurrent_futures.html"><strong aria-hidden="true">7.</strong> Bonus: concurrent futures</a></li></ol>
|
||||
</div>
|
||||
<div id="sidebar-resize-handle" class="sidebar-resize-handle"></div>
|
||||
</nav>
|
||||
|
||||
<div id="page-wrapper" class="page-wrapper">
|
||||
|
||||
<div class="page">
|
||||
|
||||
<div id="menu-bar" class="menu-bar">
|
||||
<div id="menu-bar-sticky-container">
|
||||
<div class="left-buttons">
|
||||
<button id="sidebar-toggle" class="icon-button" type="button" title="Toggle Table of Contents" aria-label="Toggle Table of Contents" aria-controls="sidebar">
|
||||
<i class="fa fa-bars"></i>
|
||||
</button>
|
||||
<button id="theme-toggle" class="icon-button" type="button" title="Change theme" aria-label="Change theme" aria-haspopup="true" aria-expanded="false" aria-controls="theme-list">
|
||||
<i class="fa fa-paint-brush"></i>
|
||||
</button>
|
||||
<ul id="theme-list" class="theme-popup" aria-label="Themes" role="menu">
|
||||
<li role="none"><button role="menuitem" class="theme" id="light">Light (default)</button></li>
|
||||
<li role="none"><button role="menuitem" class="theme" id="rust">Rust</button></li>
|
||||
<li role="none"><button role="menuitem" class="theme" id="coal">Coal</button></li>
|
||||
<li role="none"><button role="menuitem" class="theme" id="navy">Navy</button></li>
|
||||
<li role="none"><button role="menuitem" class="theme" id="ayu">Ayu</button></li>
|
||||
</ul>
|
||||
|
||||
<button id="search-toggle" class="icon-button" type="button" title="Search. (Shortkey: s)" aria-label="Toggle Searchbar" aria-expanded="false" aria-keyshortcuts="S" aria-controls="searchbar">
|
||||
<i class="fa fa-search"></i>
|
||||
</button>
|
||||
|
||||
</div>
|
||||
|
||||
<h1 class="menu-title">Futures Explained in 200 Lines of Rust</h1>
|
||||
|
||||
<div class="right-buttons">
|
||||
<a href="print.html" title="Print this book" aria-label="Print this book">
|
||||
<i id="print-button" class="fa fa-print"></i>
|
||||
</a>
|
||||
|
||||
</div>
|
||||
</div>
|
||||
</div>
|
||||
|
||||
|
||||
<div id="search-wrapper" class="hidden">
|
||||
<form id="searchbar-outer" class="searchbar-outer">
|
||||
<input type="search" name="search" id="searchbar" name="searchbar" placeholder="Search this book ..." aria-controls="searchresults-outer" aria-describedby="searchresults-header">
|
||||
</form>
|
||||
<div id="searchresults-outer" class="searchresults-outer hidden">
|
||||
<div id="searchresults-header" class="searchresults-header"></div>
|
||||
<ul id="searchresults">
|
||||
</ul>
|
||||
</div>
|
||||
</div>
|
||||
|
||||
|
||||
<!-- Apply ARIA attributes after the sidebar and the sidebar toggle button are added to the DOM -->
|
||||
<script type="text/javascript">
|
||||
document.getElementById('sidebar-toggle').setAttribute('aria-expanded', sidebar === 'visible');
|
||||
document.getElementById('sidebar').setAttribute('aria-hidden', sidebar !== 'visible');
|
||||
Array.from(document.querySelectorAll('#sidebar a')).forEach(function(link) {
|
||||
link.setAttribute('tabIndex', sidebar === 'visible' ? 0 : -1);
|
||||
});
|
||||
</script>
|
||||
|
||||
<div id="content" class="content">
|
||||
<main>
|
||||
<h1><a class="header" href="#naive-example" id="naive-example">Naive example</a></h1>
|
||||
<pre><pre class="playpen"><code class="language-rust">use std::sync::atomic::{AtomicUsize, Ordering};
|
||||
use std::sync::mpsc::{channel, Sender};
|
||||
use std::sync::{Arc, Mutex};
|
||||
use std::thread::{self, JoinHandle};
|
||||
use std::time::{Duration, Instant};
|
||||
|
||||
fn main() {
|
||||
let readylist = Arc::new(Mutex::new(vec![]));
|
||||
let mut reactor = Reactor::new();
|
||||
|
||||
let mywaker = MyWaker::new(1, thread::current(), readylist.clone());
|
||||
reactor.register(2, mywaker);
|
||||
|
||||
let mywaker = MyWaker::new(2, thread::current(), readylist.clone());
|
||||
reactor.register(2, mywaker);
|
||||
|
||||
executor_run(reactor, readylist);
|
||||
}
|
||||
// ====== EXECUTOR ======
|
||||
fn executor_run(mut reactor: Reactor, rl: Arc<Mutex<Vec<usize>>>) {
|
||||
let start = Instant::now();
|
||||
loop {
|
||||
let mut rl_locked = rl.lock().unwrap();
|
||||
while let Some(event) = rl_locked.pop() {
|
||||
let dur = (Instant::now() - start).as_secs_f32();
|
||||
println!("Event {} just happened at time: {:.2}.", event, dur);
|
||||
reactor.outstanding.fetch_sub(1, Ordering::Relaxed);
|
||||
}
|
||||
drop(rl_locked);
|
||||
|
||||
if reactor.outstanding.load(Ordering::Relaxed) == 0 {
|
||||
reactor.close();
|
||||
break;
|
||||
}
|
||||
|
||||
thread::park();
|
||||
}
|
||||
}
|
||||
|
||||
// ====== "FUTURE" IMPL ======
|
||||
#[derive(Debug)]
|
||||
struct MyWaker {
|
||||
id: usize,
|
||||
thread: thread::Thread,
|
||||
readylist: Arc<Mutex<Vec<usize>>>,
|
||||
}
|
||||
|
||||
impl MyWaker {
|
||||
fn new(id: usize, thread: thread::Thread, readylist: Arc<Mutex<Vec<usize>>>) -> Self {
|
||||
MyWaker {
|
||||
id,
|
||||
thread,
|
||||
readylist,
|
||||
}
|
||||
}
|
||||
|
||||
fn wake(&self) {
|
||||
self.readylist.lock().map(|mut rl| rl.push(self.id)).unwrap();
|
||||
self.thread.unpark();
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
#[derive(Debug, Clone)]
|
||||
pub struct Task {
|
||||
id: usize,
|
||||
pending: bool,
|
||||
}
|
||||
|
||||
// ===== REACTOR =====
|
||||
struct Reactor {
|
||||
dispatcher: Sender<Event>,
|
||||
handle: Option<JoinHandle<()>>,
|
||||
outstanding: AtomicUsize,
|
||||
}
|
||||
#[derive(Debug)]
|
||||
enum Event {
|
||||
Close,
|
||||
Simple(MyWaker, u64),
|
||||
}
|
||||
|
||||
impl Reactor {
|
||||
fn new() -> Self {
|
||||
let (tx, rx) = channel::<Event>();
|
||||
let mut handles = vec![];
|
||||
let handle = thread::spawn(move || {
|
||||
// This simulates some I/O resource
|
||||
for event in rx {
|
||||
match event {
|
||||
Event::Close => break,
|
||||
Event::Simple(mywaker, duration) => {
|
||||
let event_handle = thread::spawn(move || {
|
||||
thread::sleep(Duration::from_secs(duration));
|
||||
mywaker.wake();
|
||||
});
|
||||
handles.push(event_handle);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
for handle in handles {
|
||||
handle.join().unwrap();
|
||||
}
|
||||
});
|
||||
|
||||
Reactor {
|
||||
dispatcher: tx,
|
||||
handle: Some(handle),
|
||||
outstanding: AtomicUsize::new(0),
|
||||
}
|
||||
}
|
||||
|
||||
fn register(&mut self, duration: u64, mywaker: MyWaker) {
|
||||
self.dispatcher
|
||||
.send(Event::Simple(mywaker, duration))
|
||||
.unwrap();
|
||||
self.outstanding.fetch_add(1, Ordering::Relaxed);
|
||||
}
|
||||
|
||||
fn close(&mut self) {
|
||||
self.dispatcher.send(Event::Close).unwrap();
|
||||
}
|
||||
}
|
||||
|
||||
impl Drop for Reactor {
|
||||
fn drop(&mut self) {
|
||||
self.handle.take().map(|h| h.join().unwrap()).unwrap();
|
||||
}
|
||||
}
|
||||
</code></pre></pre>
|
||||
<pre><pre class="playpen"><code class="language-rust">use std::sync::atomic::{AtomicUsize, Ordering};
|
||||
use std::sync::mpsc::{channel, Sender};
|
||||
use std::sync::{Arc, Mutex};
|
||||
use std::thread::{self, JoinHandle};
|
||||
use std::time::{Duration, Instant};
|
||||
|
||||
fn main() {
|
||||
let readylist = Arc::new(Mutex::new(vec![]));
|
||||
let mut reactor = Reactor::new();
|
||||
|
||||
let mywaker = MyWaker::new(1, thread::current(), readylist.clone());
|
||||
reactor.register(2, mywaker);
|
||||
|
||||
let mywaker = MyWaker::new(2, thread::current(), readylist.clone());
|
||||
reactor.register(2, mywaker);
|
||||
|
||||
executor_run(reactor, readylist);
|
||||
}
|
||||
<span class="boring">// ====== EXECUTOR ======
|
||||
</span><span class="boring">fn executor_run(mut reactor: Reactor, rl: Arc<Mutex<Vec<usize>>>) {
|
||||
</span><span class="boring"> let start = Instant::now();
|
||||
</span><span class="boring"> loop {
|
||||
</span><span class="boring"> let mut rl_locked = rl.lock().unwrap();
|
||||
</span><span class="boring"> while let Some(event) = rl_locked.pop() {
|
||||
</span><span class="boring"> let dur = (Instant::now() - start).as_secs_f32();
|
||||
</span><span class="boring"> println!("Event {} just happened at time: {:.2}.", event, dur);
|
||||
</span><span class="boring"> reactor.outstanding.fetch_sub(1, Ordering::Relaxed);
|
||||
</span><span class="boring"> }
|
||||
</span><span class="boring"> drop(rl_locked);
|
||||
</span><span class="boring">
|
||||
</span><span class="boring"> if reactor.outstanding.load(Ordering::Relaxed) == 0 {
|
||||
</span><span class="boring"> reactor.close();
|
||||
</span><span class="boring"> break;
|
||||
</span><span class="boring"> }
|
||||
</span><span class="boring">
|
||||
</span><span class="boring"> thread::park();
|
||||
</span><span class="boring"> }
|
||||
</span><span class="boring">}
|
||||
</span><span class="boring">
|
||||
</span><span class="boring">// ====== "FUTURE" IMPL ======
|
||||
</span><span class="boring">#[derive(Debug)]
|
||||
</span><span class="boring">struct MyWaker {
|
||||
</span><span class="boring"> id: usize,
|
||||
</span><span class="boring"> thread: thread::Thread,
|
||||
</span><span class="boring"> readylist: Arc<Mutex<Vec<usize>>>,
|
||||
</span><span class="boring">}
|
||||
</span><span class="boring">
|
||||
</span><span class="boring">impl MyWaker {
|
||||
</span><span class="boring"> fn new(id: usize, thread: thread::Thread, readylist: Arc<Mutex<Vec<usize>>>) -> Self {
|
||||
</span><span class="boring"> MyWaker {
|
||||
</span><span class="boring"> id,
|
||||
</span><span class="boring"> thread,
|
||||
</span><span class="boring"> readylist,
|
||||
</span><span class="boring"> }
|
||||
</span><span class="boring"> }
|
||||
</span><span class="boring">
|
||||
</span><span class="boring"> fn wake(&self) {
|
||||
</span><span class="boring"> self.readylist.lock().map(|mut rl| rl.push(self.id)).unwrap();
|
||||
</span><span class="boring"> self.thread.unpark();
|
||||
</span><span class="boring"> }
|
||||
</span><span class="boring">}
|
||||
</span><span class="boring">
|
||||
</span><span class="boring">
|
||||
</span><span class="boring">#[derive(Debug, Clone)]
|
||||
</span><span class="boring">pub struct Task {
|
||||
</span><span class="boring"> id: usize,
|
||||
</span><span class="boring"> pending: bool,
|
||||
</span><span class="boring">}
|
||||
</span><span class="boring">
|
||||
</span><span class="boring">// ===== REACTOR =====
|
||||
</span><span class="boring">struct Reactor {
|
||||
</span><span class="boring"> dispatcher: Sender<Event>,
|
||||
</span><span class="boring"> handle: Option<JoinHandle<()>>,
|
||||
</span><span class="boring"> outstanding: AtomicUsize,
|
||||
</span><span class="boring">}
|
||||
</span><span class="boring">#[derive(Debug)]
|
||||
</span><span class="boring">enum Event {
|
||||
</span><span class="boring"> Close,
|
||||
</span><span class="boring"> Simple(MyWaker, u64),
|
||||
</span><span class="boring">}
|
||||
</span><span class="boring">
|
||||
</span><span class="boring">impl Reactor {
|
||||
</span><span class="boring"> fn new() -> Self {
|
||||
</span><span class="boring"> let (tx, rx) = channel::<Event>();
|
||||
</span><span class="boring"> let mut handles = vec![];
|
||||
</span><span class="boring"> let handle = thread::spawn(move || {
|
||||
</span><span class="boring"> // This simulates some I/O resource
|
||||
</span><span class="boring"> for event in rx {
|
||||
</span><span class="boring"> match event {
|
||||
</span><span class="boring"> Event::Close => break,
|
||||
</span><span class="boring"> Event::Simple(mywaker, duration) => {
|
||||
</span><span class="boring"> let event_handle = thread::spawn(move || {
|
||||
</span><span class="boring"> thread::sleep(Duration::from_secs(duration));
|
||||
</span><span class="boring"> mywaker.wake();
|
||||
</span><span class="boring"> });
|
||||
</span><span class="boring"> handles.push(event_handle);
|
||||
</span><span class="boring"> }
|
||||
</span><span class="boring"> }
|
||||
</span><span class="boring"> }
|
||||
</span><span class="boring">
|
||||
</span><span class="boring"> for handle in handles {
|
||||
</span><span class="boring"> handle.join().unwrap();
|
||||
</span><span class="boring"> }
|
||||
</span><span class="boring"> });
|
||||
</span><span class="boring">
|
||||
</span><span class="boring"> Reactor {
|
||||
</span><span class="boring"> dispatcher: tx,
|
||||
</span><span class="boring"> handle: Some(handle),
|
||||
</span><span class="boring"> outstanding: AtomicUsize::new(0),
|
||||
</span><span class="boring"> }
|
||||
</span><span class="boring"> }
|
||||
</span><span class="boring">
|
||||
</span><span class="boring"> fn register(&mut self, duration: u64, mywaker: MyWaker) {
|
||||
</span><span class="boring"> self.dispatcher
|
||||
</span><span class="boring"> .send(Event::Simple(mywaker, duration))
|
||||
</span><span class="boring"> .unwrap();
|
||||
</span><span class="boring"> self.outstanding.fetch_add(1, Ordering::Relaxed);
|
||||
</span><span class="boring"> }
|
||||
</span><span class="boring">
|
||||
</span><span class="boring"> fn close(&mut self) {
|
||||
</span><span class="boring"> self.dispatcher.send(Event::Close).unwrap();
|
||||
</span><span class="boring"> }
|
||||
</span><span class="boring">}
|
||||
</span><span class="boring">
|
||||
</span><span class="boring">impl Drop for Reactor {
|
||||
</span><span class="boring"> fn drop(&mut self) {
|
||||
</span><span class="boring"> self.handle.take().map(|h| h.join().unwrap()).unwrap();
|
||||
</span><span class="boring"> }
|
||||
</span><span class="boring">}
|
||||
</span></code></pre></pre>
|
||||
|
||||
</main>
|
||||
|
||||
<nav class="nav-wrapper" aria-label="Page navigation">
|
||||
<!-- Mobile navigation buttons -->
|
||||
|
||||
<a rel="prev" href="0_1_background_information.html" class="mobile-nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left">
|
||||
<i class="fa fa-angle-left"></i>
|
||||
</a>
|
||||
|
||||
|
||||
|
||||
<a rel="next" href="0_3_proper_waker.html" class="mobile-nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right">
|
||||
<i class="fa fa-angle-right"></i>
|
||||
</a>
|
||||
|
||||
|
||||
<div style="clear: both"></div>
|
||||
</nav>
|
||||
</div>
|
||||
</div>
|
||||
|
||||
<nav class="nav-wide-wrapper" aria-label="Page navigation">
|
||||
|
||||
<a href="0_1_background_information.html" class="nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left">
|
||||
<i class="fa fa-angle-left"></i>
|
||||
</a>
|
||||
|
||||
|
||||
|
||||
<a href="0_3_proper_waker.html" class="nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right">
|
||||
<i class="fa fa-angle-right"></i>
|
||||
</a>
|
||||
|
||||
</nav>
|
||||
|
||||
</div>
|
||||
|
||||
|
||||
<!-- Livereload script (if served using the cli tool) -->
|
||||
<script type="text/javascript">
|
||||
var socket = new WebSocket("ws://localhost:3001");
|
||||
socket.onmessage = function (event) {
|
||||
if (event.data === "reload") {
|
||||
socket.close();
|
||||
location.reload(true); // force reload from server (not from cache)
|
||||
}
|
||||
};
|
||||
|
||||
window.onbeforeunload = function() {
|
||||
socket.close();
|
||||
}
|
||||
</script>
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
<script type="text/javascript">
|
||||
window.playpen_copyable = true;
|
||||
</script>
|
||||
|
||||
|
||||
|
||||
<script src="ace.js" type="text/javascript" charset="utf-8"></script>
|
||||
<script src="editor.js" type="text/javascript" charset="utf-8"></script>
|
||||
<script src="mode-rust.js" type="text/javascript" charset="utf-8"></script>
|
||||
<script src="theme-dawn.js" type="text/javascript" charset="utf-8"></script>
|
||||
<script src="theme-tomorrow_night.js" type="text/javascript" charset="utf-8"></script>
|
||||
|
||||
|
||||
|
||||
<script src="elasticlunr.min.js" type="text/javascript" charset="utf-8"></script>
|
||||
<script src="mark.min.js" type="text/javascript" charset="utf-8"></script>
|
||||
<script src="searcher.js" type="text/javascript" charset="utf-8"></script>
|
||||
|
||||
|
||||
<script src="clipboard.min.js" type="text/javascript" charset="utf-8"></script>
|
||||
<script src="highlight.js" type="text/javascript" charset="utf-8"></script>
|
||||
<script src="book.js" type="text/javascript" charset="utf-8"></script>
|
||||
|
||||
<!-- Custom JS scripts -->
|
||||
|
||||
|
||||
|
||||
|
||||
</body>
|
||||
</html>
|
||||
Reference in New Issue
Block a user