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TCPSTREAM IN RUST AND NAGLE’S ALGORITHM – Create Your Own Event Queue-2
The last part of main is simply to write FINISHED to the console to let us know we exited main at that point. The last bit of code in this chapter is the handle_events function. This function takes two arguments, a slice of Event structs and a mutable slice of TcpStream objects. Let’s take a…
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TCPSTREAM IN RUST AND NAGLE’S ALGORITHM – Create Your Own Event Queue-1
Here is a little fact for you (I originally intended to call it a “fun fact,” but realized that’s stretching the concept of “fun” just a little too far!). In Rust’s TcpStream, and, more importantly, most APIs that aim to mimic the standard library’s TcpStream such as mio or Tokio, the stream is created with…
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NOTE – Create Your Own Event Queue
For simplicity, we use the index the event will have in the streams collection as its ID. This ID will be the same as the i variable in our loop. For example, in the first loop, i will be 0; it will also be the first stream to be pushed to our streams collection, so…
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NOTE – Create Your Own Event Queue
We would get a value of 0 if a timeout elapses before an event has happened. The last thing we do is to make an unsafe call to events.set_len(res as usize). This function is unsafe since we could potentially set the length so that we would access memory that’s not been initialized yet in safe…
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Level-triggered versus edge-triggered events – Create Your Own Event Queue
In a perfect world, we wouldn’t need to discuss this, but when working with epoll, it’s almost impossible to avoid having to know about the difference. It’s not obvious by reading the documentation, especially not if you haven’t had previous experience with these terms before. The interesting part of this is that it allows us…
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The ffi module – Create Your Own Event Queue-2
The last part of the code in this file is the Event struct: ch04/a-epoll/src/ffi.rs#[derive(Debug)]#[repr(C, packed)]pub struct Event { pub(crate) events: u32, // Token to identify event pub(crate) epoll_data: usize,}impl Event { pub fn token(&self) -> usize { self.epoll_data }} This structure is used to communicate to the operating system in epoll_ctl, and the operating system uses the same structure to communicate…
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The ffi module – Create Your Own Event Queue-1
Note The reason for doing file I/O in a thread pool is that there have historically been poor cross-platform APIs for non-blocking file I/O. While it’s true that many runtimes choose to relegate this task to a thread pool making blocking calls to the OS, it might not be true in the future as the…
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IMPORTANT NOTE – Create Your Own Event Queue
By moving the concern of registering interests to a separate struct like this, users can call Registry::try_clone to get an owned Registry instance. This instance can be passed to, or shared through Arc<Registry> with, other threads, allowing multiple threads to register interest to the same Poll instance even when Poll is blocking another thread while…
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THE DELAY SERVER – Create Your Own Event Queue
This example relies on calls made to a server that delays the response for a configurable duration. In the repository, there is a project named delayserver in the root folder. You can set up the server by simply entering the folder in a separate console window and writing cargo run. Just leave the server running…
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The highest level of abstraction – Understanding OS-Backed Event Queues, System Calls, and Cross-Platform Abstractions
This is simple, but I wanted to add this just for completeness. Rust standard library wraps the calls to the underlying OS APIs for us, so we don’t have to care about what syscalls to invoke.fn main() { println!(“Hello world from the standard library”);} Congratulations! You’ve now written the same syscall using three levels of abstraction.…
