Committing a set of basic rust examples.
This contains code and tests for several basic rust skills.
This commit is contained in:
348
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348
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||||||
|
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||||
|
checksum = "24d5b23dc417412679681396f2b49f3de8c1473deb516bd34410872eff51ed0d"
|
||||||
|
|
||||||
|
[[package]]
|
||||||
|
name = "windows_x86_64_msvc"
|
||||||
|
version = "0.52.6"
|
||||||
|
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||||
|
checksum = "589f6da84c646204747d1270a2a5661ea66ed1cced2631d546fdfb155959f9ec"
|
||||||
@ -1,6 +1,6 @@
|
|||||||
[package]
|
[package]
|
||||||
name = "example"
|
name = "example"
|
||||||
version = "0.0.0"
|
version = "1.0.0"
|
||||||
edition = "2021"
|
edition = "2021"
|
||||||
description = "Just a small sample of Rust code."
|
description = "Just a small sample of Rust code."
|
||||||
repository = "/myrddin/example"
|
repository = "/myrddin/example"
|
||||||
@ -11,3 +11,4 @@ license = "Apache-2.0"
|
|||||||
|
|
||||||
|
|
||||||
[dependencies]
|
[dependencies]
|
||||||
|
tokio = { version = "1.45.1", features = ["full", "test-util"] }
|
||||||
|
|||||||
59
README.md
59
README.md
@ -1,14 +1,67 @@
|
|||||||
# example
|
# Example
|
||||||
|
|
||||||
Just a small sample of Rust code.
|
A lightweight collection of examples demonstrating essential Rust features,
|
||||||
|
without relying on external dependencies (except `tokio`).
|
||||||
|
|
||||||
|
|
||||||
|
---
|
||||||
|
|
||||||
|
|
||||||
|
### Concepts Covered
|
||||||
|
|
||||||
|
- Arrays and Iteration
|
||||||
|
- Lifetimes and Borrowing
|
||||||
|
- Error Handling with `Result`, `?`, and custom messages
|
||||||
|
- Async Programming using `#[tokio::main]`
|
||||||
|
- File I/O with the standard library
|
||||||
|
- Unit and async testing
|
||||||
|
|
||||||
|
### Key Functions
|
||||||
|
|
||||||
|
| Function | Description |
|
||||||
|
|------------------|--------------------------------------------------------|
|
||||||
|
| `longest` | Returns the longest string in a slice without copying. |
|
||||||
|
| `read_and_parse` | Reads a file and parses its content into an integer. |
|
||||||
|
| `run_tasks` | Demonstrates spawning and awaiting async tasks. |
|
||||||
|
|
||||||
|
### Testing
|
||||||
|
|
||||||
|
Includes both synchronous and asynchronous unit tests under a
|
||||||
|
`#[cfg(test)]` module.
|
||||||
|
|
||||||
|
|
||||||
|
---
|
||||||
|
|
||||||
|
|
||||||
|
## Testing & Extending
|
||||||
|
|
||||||
|
|
||||||
|
---
|
||||||
|
|
||||||
|
|
||||||
|
## Requirements
|
||||||
|
|
||||||
|
- Rust 1.76+ (for full language support)
|
||||||
|
- [Tokio 1.37+](https://docs.rs/tokio) (for async runtime)
|
||||||
|
|
||||||
|
|
||||||
|
---
|
||||||
|
|
||||||
|
|
||||||
|
## Project Structure
|
||||||
|
|
||||||
|
```text
|
||||||
|
src/
|
||||||
|
├── info.rs # Crate information from Cargo.
|
||||||
|
├── main.rs # Foundational examples.
|
||||||
|
```
|
||||||
|
|
||||||
|
|
||||||
---
|
---
|
||||||
|
|
||||||
## Copyright & License
|
## Copyright & License
|
||||||
|
|
||||||
Copyright 2025 CyberMages LLC
|
Copyright 2025 Jason Travis Smith
|
||||||
|
|
||||||
Licensed under the Apache License, Version 2.0 (the "License");
|
Licensed under the Apache License, Version 2.0 (the "License");
|
||||||
you may not use this library except in compliance with the License.
|
you may not use this library except in compliance with the License.
|
||||||
|
|||||||
@ -1,3 +1,6 @@
|
|||||||
|
// SPDX-License-Identifier: Apache-2.0
|
||||||
|
// Sealed with Magistamp.
|
||||||
|
|
||||||
//! This is where the cargo build information can be retrieved from.
|
//! This is where the cargo build information can be retrieved from.
|
||||||
|
|
||||||
|
|
||||||
|
|||||||
257
src/main.rs
257
src/main.rs
@ -1,18 +1,259 @@
|
|||||||
//! Just a small sample of Rust code.
|
// SPDX-License-Identifier: Apache-2.0
|
||||||
|
// Sealed with Magistamp.
|
||||||
|
|
||||||
mod info;
|
//! # Skills Example
|
||||||
|
//!
|
||||||
|
//! This demonstrates several foundational Rust concepts in a simple,
|
||||||
|
//! self-contained example using only the tokio runtime and no other crates.
|
||||||
|
//!
|
||||||
|
//! It includes working examples of:
|
||||||
|
//!
|
||||||
|
//! - **Arrays and iteration**
|
||||||
|
//! - **Error handling with `Result` and `?`**
|
||||||
|
//! - **File I/O using the standard library**
|
||||||
|
//! - **Asynchronous programming with `tokio`**
|
||||||
|
//! - **Basic unit and async testing**
|
||||||
|
//!
|
||||||
|
//! ## Included Functions
|
||||||
|
//!
|
||||||
|
//! - `longest`: Finds the longest string in a slice without copying.
|
||||||
|
//! - `read_and_parse`: Reads a file and parses its contents as an integer.
|
||||||
|
//! - `run_tasks`: Spawns multiple asynchronous tasks and waits for them to
|
||||||
|
//! complete.
|
||||||
|
//!
|
||||||
|
//! The `main` function is marked with the `#[tokio::main]` attribute and serves
|
||||||
|
//! as the entry point, demonstrating how to run async code in a typical binary.
|
||||||
|
//!
|
||||||
|
//! Unit tests are included under the `#[cfg(test)]` module to validate
|
||||||
|
//! functionality and show best practices.
|
||||||
|
|
||||||
|
use std::io::Read;
|
||||||
|
use std::pin::Pin;
|
||||||
|
|
||||||
|
use tokio::time::{sleep, Duration};
|
||||||
|
|
||||||
|
|
||||||
|
/// An async trait that can be used as a dyn trait.
|
||||||
/// Print the version.
|
pub trait Job: Send + Sync
|
||||||
fn print_version()
|
|
||||||
{
|
{
|
||||||
println!("{} v{}", info::get_name(), info::get_version());
|
fn name(&self) -> &str;
|
||||||
|
|
||||||
|
/// This function needs to be async.
|
||||||
|
/// Here we Pin a heap allocated future so that it can be referenced safely.
|
||||||
|
/// The output is then set to the desired output of the function.
|
||||||
|
///
|
||||||
|
/// Inside the implementation all you need to do is:
|
||||||
|
/// ```ignore
|
||||||
|
/// Box::pin(async move
|
||||||
|
/// {
|
||||||
|
/// // Place your functions code here.
|
||||||
|
/// })
|
||||||
|
/// ```
|
||||||
|
fn run<'a>(
|
||||||
|
&self)
|
||||||
|
-> Pin<Box<dyn core::future::Future<Output = Result<String, String>>
|
||||||
|
+ Send
|
||||||
|
+ 'a>>
|
||||||
|
where Self: Sync + 'a;
|
||||||
|
}
|
||||||
|
|
||||||
|
|
||||||
|
/// Takes a list of strings and returns the longest one without
|
||||||
|
/// copying the strings.
|
||||||
|
///
|
||||||
|
/// The lifetime here is because we are returning the borrow reference of
|
||||||
|
/// the passed in String. The lifetime tells the borrow checker that the
|
||||||
|
/// returned reference needs to live as long as the owning String does.
|
||||||
|
///
|
||||||
|
/// ```
|
||||||
|
/// # use example::longest;
|
||||||
|
/// let strings: [String; 5] = [String::from("Jason"),
|
||||||
|
/// String::from("is"),
|
||||||
|
/// String::from("an"),
|
||||||
|
/// String::from("awesome"),
|
||||||
|
/// String::from("programmer")];
|
||||||
|
///
|
||||||
|
/// assert_eq!(Some(strings[4].as_str()), longest(&strings));
|
||||||
|
/// ```
|
||||||
|
pub fn longest<'a>(strings: &'a [String]) -> Option<&'a str>
|
||||||
|
{
|
||||||
|
if strings.is_empty()
|
||||||
|
{
|
||||||
|
eprintln!("No strings detected");
|
||||||
|
return None;
|
||||||
|
}
|
||||||
|
|
||||||
|
// This is the current longest string. (index, length)
|
||||||
|
//
|
||||||
|
// This can also be done with functional style:
|
||||||
|
// strings.iter().max_by_key(|s| s.len()).map(|s| s.as_str())
|
||||||
|
let mut longest: (usize, usize) = (0, 0);
|
||||||
|
for (index, string) in strings.iter().enumerate()
|
||||||
|
{
|
||||||
|
if string.len() > longest.1
|
||||||
|
{
|
||||||
|
longest = (index, string.len());
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
Some(&strings[longest.0])
|
||||||
}
|
}
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
fn main()
|
/// Read and parse the contents of a file as an integer.
|
||||||
|
///
|
||||||
|
/// ```
|
||||||
|
/// # fn try_main() -> Result<(), Box<dyn std::error::Error>>
|
||||||
|
/// # {
|
||||||
|
/// # use example::read_and_parse;
|
||||||
|
/// use std::io::{ErrorKind, Write};
|
||||||
|
///
|
||||||
|
/// let val: i32 = 12345;
|
||||||
|
/// let mut write_target = std::env::temp_dir();
|
||||||
|
/// write_target.push("read_test");
|
||||||
|
/// write_target.set_extension("txt");
|
||||||
|
///
|
||||||
|
/// let read_target = write_target.clone();
|
||||||
|
///
|
||||||
|
/// let mut file = std::fs::File::create(write_target)?;
|
||||||
|
/// file.write_all(format!("{}", val).as_bytes())?;
|
||||||
|
///
|
||||||
|
///
|
||||||
|
/// match read_target.to_str()
|
||||||
|
/// {
|
||||||
|
/// Some(path) =>
|
||||||
|
/// {
|
||||||
|
/// assert_eq!(val, read_and_parse(path)?);
|
||||||
|
/// Ok(())
|
||||||
|
/// }
|
||||||
|
/// None =>
|
||||||
|
/// {
|
||||||
|
/// Err(Box::new(std::io::Error::new(ErrorKind::InvalidData,
|
||||||
|
/// "Unable to turn target file into \
|
||||||
|
/// a UTF-8 string.")))
|
||||||
|
/// }
|
||||||
|
/// }
|
||||||
|
/// # }
|
||||||
|
/// # fn main()
|
||||||
|
/// # {
|
||||||
|
/// # try_main().unwrap();
|
||||||
|
/// # }
|
||||||
|
/// ```
|
||||||
|
pub fn read_and_parse<P>(path: P) -> Result<i32, Box<dyn std::error::Error>>
|
||||||
|
where P: AsRef<std::path::Path>
|
||||||
{
|
{
|
||||||
print_version();
|
let mut file = std::fs::File::open(path)?;
|
||||||
|
let mut contents = String::new();
|
||||||
|
|
||||||
|
file.read_to_string(&mut contents)?;
|
||||||
|
|
||||||
|
let val: i32 = contents.parse()?;
|
||||||
|
|
||||||
|
Ok(val)
|
||||||
|
}
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
|
/// Spawns 5 tasks, each sleeping for a different duration,
|
||||||
|
/// then prints when each finishes.
|
||||||
|
pub async fn run_tasks()
|
||||||
|
{
|
||||||
|
let tasks: tokio::task::JoinSet<_> =
|
||||||
|
(0..5).map(|i| {
|
||||||
|
async move {
|
||||||
|
sleep(Duration::from_millis(500 + (i * 10))).await;
|
||||||
|
println!("Finished!");
|
||||||
|
}
|
||||||
|
})
|
||||||
|
.collect();
|
||||||
|
|
||||||
|
let _result = tasks.join_all().await;
|
||||||
|
}
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
|
/// Where everything gets started.
|
||||||
|
///
|
||||||
|
/// That's not really true. Rust sets up a
|
||||||
|
/// function that calls this one, which is similar to what tokio does when
|
||||||
|
/// you use the tokio::main attribute. However, this is the common starting
|
||||||
|
/// point for Rust binaries.
|
||||||
|
///
|
||||||
|
/// If you wanted to handle the actual main on your own do something
|
||||||
|
/// like below. Be warned that you will need to parse the arguments passed
|
||||||
|
/// to your program yourself and it is a different starting function call
|
||||||
|
/// on certain platforms.
|
||||||
|
/// ```ignore
|
||||||
|
/// #[no_mangle]
|
||||||
|
/// #[inline(never)]
|
||||||
|
/// #[start]
|
||||||
|
/// pub extern "C" fn main(argc: i32, argv: *const *const u8) -> i32
|
||||||
|
/// {
|
||||||
|
/// }
|
||||||
|
/// ```
|
||||||
|
#[tokio::main]
|
||||||
|
async fn main()
|
||||||
|
{
|
||||||
|
run_tasks().await;
|
||||||
|
}
|
||||||
|
|
||||||
|
|
||||||
|
|
||||||
|
#[cfg(test)]
|
||||||
|
mod test
|
||||||
|
{
|
||||||
|
use std::io::Write;
|
||||||
|
|
||||||
|
use crate::{longest, read_and_parse, run_tasks};
|
||||||
|
|
||||||
|
|
||||||
|
#[test]
|
||||||
|
fn longest_test() -> Result<(), String>
|
||||||
|
{
|
||||||
|
let strings: [String; 5] = [String::from("Jason"),
|
||||||
|
String::from("is"),
|
||||||
|
String::from("an"),
|
||||||
|
String::from("awesome"),
|
||||||
|
String::from("programmer")];
|
||||||
|
|
||||||
|
// Could also be Some(&*strings[4]). as_str() is easier to read though.
|
||||||
|
assert_eq!(Some(strings[4].as_str()), longest(&strings));
|
||||||
|
Ok(())
|
||||||
|
}
|
||||||
|
|
||||||
|
#[test]
|
||||||
|
fn read_parse_test() -> Result<(), Box<dyn std::error::Error>>
|
||||||
|
{
|
||||||
|
let val: i32 = 12345;
|
||||||
|
let mut write_target = std::env::temp_dir();
|
||||||
|
write_target.push("read_test");
|
||||||
|
write_target.set_extension("txt");
|
||||||
|
|
||||||
|
let read_target = write_target.clone();
|
||||||
|
|
||||||
|
let mut file = std::fs::File::create(write_target)?;
|
||||||
|
file.write_all(format!("{}", val).as_bytes())?;
|
||||||
|
|
||||||
|
match read_target.to_str()
|
||||||
|
{
|
||||||
|
Some(path) =>
|
||||||
|
{
|
||||||
|
assert_eq!(val, read_and_parse(path)?);
|
||||||
|
Ok(())
|
||||||
|
}
|
||||||
|
None =>
|
||||||
|
{
|
||||||
|
Err(Box::new(std::io::Error::new(std::io::ErrorKind::InvalidData,
|
||||||
|
"Unable to turn target file \
|
||||||
|
into a UTF-8 string.")))
|
||||||
|
}
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
#[tokio::test(start_paused = true)]
|
||||||
|
async fn run_tasks_test()
|
||||||
|
{
|
||||||
|
run_tasks().await;
|
||||||
|
}
|
||||||
}
|
}
|
||||||
|
|||||||
Reference in New Issue
Block a user