public-collect/books-futures-explained
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added main example

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Carl Fredrik Samson
2020-01-30 23:57:02 +01:00
parent 59f00d69e9
commit a84faa9f3f
15 changed files with 394 additions and 259 deletions
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book/print.html
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@@ -1080,13 +1080,13 @@ caveats and is not something you'll normally see so I refer to the documentation
for that.</p>
<h3><a class="header" href="#pin-and-drop" id="pin-and-drop">Pin and Drop</a></h3>
<p>The <code>Pin</code> guarantee exists from the moment the value is pinned until it's dropped.
In the <code>Drop</code> implementation you take a mutabl reference to <code>self</code>, which means
In the <code>Drop</code> implementation you take a mutable reference to <code>self</code>, which means
extra care must be taken when implementing <code>Drop</code> for pinned types.</p>
<h2><a class="header" href="#putting-it-all-together" id="putting-it-all-together">Putting it all together</a></h2>
<p>This is exactly what we'll do when we implement our own <code>Futures</code> stay tuned,
we're soon finished.</p>
<h1><a class="header" href="#pin-1" id="pin-1">Pin</a></h1>
<pre><pre class="playpen"><code class="language-rust">use std::{
<pre><pre class="playpen"><code class="language-rust">
use std::{
future::Future, pin::Pin, sync::{mpsc::{channel, Sender}, Arc, Mutex},
task::{Context, Poll, RawWaker, RawWakerVTable, Waker},
thread::{self, JoinHandle}, time::{Duration, Instant}
@@ -1094,9 +1094,12 @@ we're soon finished.</p>
fn main() {
let start = Instant::now();
// Many runtimes create a glocal `reactor` we pass it as an argument
let reactor = Reactor::new();
let reactor = Arc::new(Mutex::new(reactor));
let future1 = Task::new(reactor.clone(), 3, 1);
let future1 = Task::new(reactor.clone(), 2, 1);
let future2 = Task::new(reactor.clone(), 1, 2);
let fut1 = async {
@@ -1112,10 +1115,8 @@ fn main() {
};
let mainfut = async {
let handle1 = spawn(fut1);
let handle2 = spawn(fut2);
handle1.await;
handle2.await;
fut1.await;
fut2.await;
};
block_on(mainfut);
@@ -1137,15 +1138,6 @@ fn block_on&lt;F: Future&gt;(mut future: F) -&gt; F::Output {
val
}
fn spawn&lt;F: Future&gt;(future: F) -&gt; Pin&lt;Box&lt;F&gt;&gt; {
let mywaker = Arc::new(MyWaker{ thread: thread::current() });
let waker = waker_into_waker(Arc::into_raw(mywaker));
let mut cx = Context::from_waker(&amp;waker);
let mut boxed = Box::pin(future);
let _ = Future::poll(boxed.as_mut(), &amp;mut cx);
boxed
}
// ====================== FUTURE IMPLEMENTATION ==============================
#[derive(Clone)]
struct MyWaker {
@@ -1310,6 +1302,21 @@ impl Drop for Reactor {
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