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// run-pass
#![allow(unused_must_use)]
// Tests that a heterogeneous list of existential `dyn` types can be put inside an Arc
// and shared between threads as long as all types fulfill Send.
// ignore-emscripten no threads support
use std::sync::Arc;
use std::sync::mpsc::channel;
use std::thread;
trait Pet {
fn name(&self, blk: Box<dyn FnMut(&str)>);
fn num_legs(&self) -> usize;
fn of_good_pedigree(&self) -> bool;
}
struct Catte {
num_whiskers: usize,
name: String,
}
struct Dogge {
bark_decibels: usize,
tricks_known: usize,
name: String,
}
struct Goldfyshe {
swim_speed: usize,
name: String,
}
impl Pet for Catte {
fn name(&self, mut blk: Box<dyn FnMut(&str)>) { blk(&self.name) }
fn num_legs(&self) -> usize { 4 }
fn of_good_pedigree(&self) -> bool { self.num_whiskers >= 4 }
}
impl Pet for Dogge {
fn name(&self, mut blk: Box<dyn FnMut(&str)>) { blk(&self.name) }
fn num_legs(&self) -> usize { 4 }
fn of_good_pedigree(&self) -> bool {
self.bark_decibels < 70 || self.tricks_known > 20
}
}
impl Pet for Goldfyshe {
fn name(&self, mut blk: Box<dyn FnMut(&str)>) { blk(&self.name) }
fn num_legs(&self) -> usize { 0 }
fn of_good_pedigree(&self) -> bool { self.swim_speed >= 500 }
}
pub fn main() {
let catte = Catte { num_whiskers: 7, name: "alonzo_church".to_string() };
let dogge1 = Dogge {
bark_decibels: 100,
tricks_known: 42,
name: "alan_turing".to_string(),
};
let dogge2 = Dogge {
bark_decibels: 55,
tricks_known: 11,
name: "albert_einstein".to_string(),
};
let fishe = Goldfyshe {
swim_speed: 998,
name: "alec_guinness".to_string(),
};
let arc = Arc::new(vec![
Box::new(catte) as Box<dyn Pet+Sync+Send>,
Box::new(dogge1) as Box<dyn Pet+Sync+Send>,
Box::new(fishe) as Box<dyn Pet+Sync+Send>,
Box::new(dogge2) as Box<dyn Pet+Sync+Send>]);
let (tx1, rx1) = channel();
let arc1 = arc.clone();
let t1 = thread::spawn(move|| { check_legs(arc1); tx1.send(()); });
let (tx2, rx2) = channel();
let arc2 = arc.clone();
let t2 = thread::spawn(move|| { check_names(arc2); tx2.send(()); });
let (tx3, rx3) = channel();
let arc3 = arc.clone();
let t3 = thread::spawn(move|| { check_pedigree(arc3); tx3.send(()); });
rx1.recv();
rx2.recv();
rx3.recv();
t1.join();
t2.join();
t3.join();
}
fn check_legs(arc: Arc<Vec<Box<dyn Pet+Sync+Send>>>) {
let mut legs = 0;
for pet in arc.iter() {
legs += pet.num_legs();
}
assert!(legs == 12);
}
fn check_names(arc: Arc<Vec<Box<dyn Pet+Sync+Send>>>) {
for pet in arc.iter() {
pet.name(Box::new(|name| {
assert!(name.as_bytes()[0] == 'a' as u8 && name.as_bytes()[1] == 'l' as u8);
}))
}
}
fn check_pedigree(arc: Arc<Vec<Box<dyn Pet+Sync+Send>>>) {
for pet in arc.iter() {
assert!(pet.of_good_pedigree());
}
}
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