Book Image

Rust Programming By Example

By : Guillaume Gomez, Antoni Boucher
Book Image

Rust Programming By Example

By: Guillaume Gomez, Antoni Boucher

Overview of this book

Rust is an open source, safe, concurrent, practical language created by Mozilla. It runs blazingly fast, prevents segfaults, and guarantees safety. This book gets you started with essential software development by guiding you through the different aspects of Rust programming. With this approach, you can bridge the gap between learning and implementing immediately. Beginning with an introduction to Rust, you’ll learn the basic aspects such as its syntax, data types, functions, generics, control flows, and more. After this, you’ll jump straight into building your first project, a Tetris game. Next you’ll build a graphical music player and work with fast, reliable networking software using Tokio, the scalable and productive asynchronous IO Rust library. Over the course of this book, you’ll explore various features of Rust Programming including its SDL features, event loop, File I/O, and the famous GTK+ widget toolkit. Through these projects, you’ll see how well Rust performs in terms of concurrency—including parallelism, reliability, improved performance, generics, macros, and thread safety. We’ll also cover some asynchronous and reactive programming aspects of Rust. By the end of the book, you’ll be comfortable building various real-world applications in Rust.
Table of Contents (18 chapters)
Title Page
Copyright and Credits
Packt Upsell
Events and Basic Game Mechanisms

Improving CPU usage

One issue you may have noticed is that when no song is playing, the software will use 100% of the CPU. This is because of the infinite loop in the music engine thread. It will do nothing except loop when the song is paused or when there's no song to play. Let's now fix this issue.

Condition variable

What we want to do is to make the thread sleep when it has nothing to do. We also want to be able to wake the thread up from the main thread. This is exactly what condition variables are for. So, let's add one to our engine. We'll start by adding a condition_variable field to the EventLoop:

struct EventLoop {
    condition_variable: Arc<(Mutex<bool>, Condvar)>,
    queue: Arc<SegQueue<Action>>,
    playing: Arc<Mutex<bool>>,

A condition variable is usually used together with a Boolean value (wrapped in a Mutex). We need to rewrite the constructor of EventLoop to initialize this new field:

impl EventLoop {
    fn new() -> Self {