implementing Lifetimes and Borrowing in Rust when Implementing a Simple Caching Mechanism
Does anyone know how to I've been banging my head against this for hours... I'm currently working on a simple caching mechanism in Rust using a HashMap to store results of expensive computations. However, I'm working with issues with lifetimes and borrowing when trying to return a reference to cached data. Here’s a simplified version of my code: ```rust use std::collections::HashMap; struct Cache<T> { data: HashMap<String, T>, } impl<T> Cache<T> where T: Clone, { fn new() -> Self { Cache { data: HashMap::new() } } fn get(&self, key: &str) -> Option<&T> { self.data.get(key) } fn insert(&mut self, key: String, value: T) { self.data.insert(key, value); } } fn main() { let mut cache: Cache<i32> = Cache::new(); cache.insert("item1".to_string(), 42); if let Some(value) = cache.get("item1") { println!("Cached value: {}", value); } } ``` When I run this code, it works as expected, but I'm concerned about borrowing rules. If I want to modify the cache while still holding a reference to a cached item, I get the following behavior: ``` behavior[E0502]: want to borrow `cache` as mutable because it is also borrowed as immutable ``` I’ve tried various ways to restructure my code, including using interior mutability with RefCell, but it feels like I'm circumventing Rust’s ownership model rather than embracing it. What would be the best practice here to allow both reads and writes to the cache without running into borrowing issues? Are there any design patterns or libraries that can help manage this type of scenario more effectively? My development environment is Linux. Thanks for your help in advance! This is happening in both development and production on Windows 11.