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nikomatsakisnikomatsakis
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‎index-template.html

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<html>
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<body>
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<h2>Rust concurrency tutorial</h2>
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<ol>
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<li> <a href="src/hello_world.rs">Hello World</a>
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<ul>
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<li>Goal: make it greet you by name
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<li>Time: 3 minutes
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</ul>
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<li> <a href="src/borrowing.rs">Borrowing</a>
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<ul>
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<li>Goal: convert this code to use borrowing
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instead so that it compiles
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<li>Time: 3 minutes
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</ul>
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<li> <a href="src/sequential_search.rs">Sequential search</a>
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<ul>
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<li>Goal: implement <code>find_best_store</code>
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<li>Time: 10 minutes
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</ul>
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<li> <a href="src/parallel_search.rs">Parallel search</a>:
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<ul>
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<li>Goal: make this actually run in parallel
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<li>Extra bonus: avoid cloning the store name
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<li>Time: 10 minutes
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</ul>
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<li> <a href="src/shared_memory.rs">Shared memory </a>:
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<ul>
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<li>Goal: Adapt your previous code to use `Arc`
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<li>Extra bonus: How can you minimize cloning the underlying shopping list?
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<li>Time: 10 minutes
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</ul>
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<li> <a href="src/mutex.rs">Introduce Mutex</a>:
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<ul>
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<li>Goal: Adapt your previous code to introduce a mutex
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and use it to find the best price
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<li>Time: 10 minutes
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</ul>
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</ol>
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</body>
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</html>

‎src/example_actor.rs renamed to ‎src/actor.rs

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‎src/borrowing.rs

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pub fn main() {
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let mut name = format!("fellow ");
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name.push_str("Rustacean");
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helper(name);
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helper(name);
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}
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fn helper(name: String) {
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println!("Hello, {}!", name);
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}

‎src/channels.rs

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#![allow(dead_code)]
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use std::collections::HashMap;
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use std::f32::INFINITY;
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use std::sync::mpsc::channel;
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use std::thread;
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struct Store {
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name: String,
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prices: HashMap<String, f32>,
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}
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impl Store {
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fn new(name: String) -> Store {
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Store {
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name: name,
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prices: HashMap::new(),
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}
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}
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fn add_item(&mut self, name: String, price: f32) {
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self.prices.insert(name, price);
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}
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fn price(&self, item_name: &str) -> f32 {
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self.prices[item_name]
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}
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}
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fn build_stores() -> Vec<Store> {
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let mut stores = vec![];
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let mut store = Store::new(format!("R-mart"));
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store.add_item(format!("chocolate"), 5.0);
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store.add_item(format!("doll"), 22.0);
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store.add_item(format!("bike"), 150.0);
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stores.push(store);
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let mut store = Store::new(format!("Bullseye"));
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store.add_item(format!("chocolate"), 2.0);
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store.add_item(format!("doll"), 23.0);
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store.add_item(format!("bike"), 145.0);
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stores.push(store);
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let mut store = Store::new(format!("Woolmart"));
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store.add_item(format!("chocolate"), 2.0);
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store.add_item(format!("doll"), 23.0);
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store.add_item(format!("bike"), 146.0);
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stores.push(store);
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stores
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}
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fn find_best_store(stores: Vec<Store>, shopping_list: &Vec<String>) -> String {
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assert!(stores.len() > 0);
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// TODO:
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// - create channel for receiving message
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// - start threads for each store, giving each a `tx` to send messages to
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// - have each thread send its name and sum
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// - find and return best name
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for store in stores {
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let shopping_list = shopping_list.clone();
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thread::spawn(move || {
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let sum = compute_sum(&store, &shopping_list);
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unimplemented!("send sum to some channel");
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});
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}
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let mut best = None;
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let mut best_price = INFINITY;
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while true { // <-- change to some suitable loop!
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let (sum, name) = unimplemented!();
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if sum < best_price {
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best = Some(name);
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best_price = sum;
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}
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}
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best.unwrap() // there will always be at least one store
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}
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fn compute_sum(store: &Store, shopping_list: &Vec<String>) -> f32 {
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shopping_list.iter()
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.map(|item_name| store.price(item_name))
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.fold(0.0, |v, u| v + u)
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}
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pub fn main() {
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let shopping_list = vec![format!("chocolate"),
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format!("doll"),
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format!("bike")];
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let stores = build_stores();
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let best_store = find_best_store(stores, &shopping_list);
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println!("Best store: {}", best_store);
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}
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‎src/example_port.rs renamed to ‎src/channels_sol.rs

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use std::collections::HashMap;
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use std::f32::INFINITY;
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use std::mem;
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use std::sync::mpsc::channel;
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use std::thread;
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assert!(stores.len() > 0);
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let (tx, rx) = channel();
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let count = stores.len();
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for store in stores {
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let shopping_list = shopping_list.clone();
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let tx = tx.clone();
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tx.send((sum, store.name)).unwrap();
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});
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}
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mem::drop(tx);
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let mut best = None;
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let mut best_price = INFINITY;
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for _ in 0 .. count {
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let (sum, name) = rx.recv().unwrap();
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for (sum, name) in rx {
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if sum < best_price {
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best = Some(name);
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best_price = sum;

‎src/example00.rs renamed to ‎src/hello_world.rs

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‎src/main.rs

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mod example_sequential_search;
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mod example_parallel_search;
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mod example_parallel_search_sol;
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mod example_port;
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mod example_channels;
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mod example_channels_sol;
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mod example_actor;
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mod example_shared_memory;
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mod example_mutex;
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example_parallel_search_sol::main();
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println!("----------------------------------------------------------------------");
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example_port::main();
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// example_channels::main(); // not expected to execute
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example_channels_sol::main();
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println!("----------------------------------------------------------------------");
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example_actor::main();

‎src/example_mutex.rs renamed to ‎src/mutex.rs

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‎src/example_parallel_search.rs renamed to ‎src/parallel_search.rs

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‎src/example_parallel_search_sol.rs renamed to ‎src/parallel_search_sol.rs

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