src/test/ui/traits/bound/in-arc.rs

   1 // run-pass
   2 #![allow(unused_must_use)]
   3 // Tests that a heterogeneous list of existential `dyn` types can be put inside an Arc
   4 // and shared between threads as long as all types fulfill Send.
   5
   6 // ignore-emscripten no threads support
   7
   8 #![feature(box_syntax)]
   9
  10 use std::sync::Arc;
  11 use std::sync::mpsc::channel;
  12 use std::thread;
  13
  14 trait Pet {
  15     fn name(&self, blk: Box<dyn FnMut(&str)>);
  16     fn num_legs(&self) -> usize;
  17     fn of_good_pedigree(&self) -> bool;
  18 }
  19
  20 struct Catte {
  21     num_whiskers: usize,
  22     name: String,
  23 }
  24
  25 struct Dogge {
  26     bark_decibels: usize,
  27     tricks_known: usize,
  28     name: String,
  29 }
  30
  31 struct Goldfyshe {
  32     swim_speed: usize,
  33     name: String,
  34 }
  35
  36 impl Pet for Catte {
  37     fn name(&self, mut blk: Box<dyn FnMut(&str)>) { blk(&self.name) }
  38     fn num_legs(&self) -> usize { 4 }
  39     fn of_good_pedigree(&self) -> bool { self.num_whiskers >= 4 }
  40 }
  41 impl Pet for Dogge {
  42     fn name(&self, mut blk: Box<dyn FnMut(&str)>) { blk(&self.name) }
  43     fn num_legs(&self) -> usize { 4 }
  44     fn of_good_pedigree(&self) -> bool {
  45         self.bark_decibels < 70 || self.tricks_known > 20
  46     }
  47 }
  48 impl Pet for Goldfyshe {
  49     fn name(&self, mut blk: Box<dyn FnMut(&str)>) { blk(&self.name) }
  50     fn num_legs(&self) -> usize { 0 }
  51     fn of_good_pedigree(&self) -> bool { self.swim_speed >= 500 }
  52 }
  53
  54 pub fn main() {
  55     let catte = Catte { num_whiskers: 7, name: "alonzo_church".to_string() };
  56     let dogge1 = Dogge {
  57         bark_decibels: 100,
  58         tricks_known: 42,
  59         name: "alan_turing".to_string(),
  60     };
  61     let dogge2 = Dogge {
  62         bark_decibels: 55,
  63         tricks_known: 11,
  64         name: "albert_einstein".to_string(),
  65     };
  66     let fishe = Goldfyshe {
  67         swim_speed: 998,
  68         name: "alec_guinness".to_string(),
  69     };
  70     let arc = Arc::new(vec![box catte  as Box<dyn Pet+Sync+Send>,
  71                             box dogge1 as Box<dyn Pet+Sync+Send>,
  72                             box fishe  as Box<dyn Pet+Sync+Send>,
  73                             box dogge2 as Box<dyn Pet+Sync+Send>]);
  74     let (tx1, rx1) = channel();
  75     let arc1 = arc.clone();
  76     let t1 = thread::spawn(move|| { check_legs(arc1); tx1.send(()); });
  77     let (tx2, rx2) = channel();
  78     let arc2 = arc.clone();
  79     let t2 = thread::spawn(move|| { check_names(arc2); tx2.send(()); });
  80     let (tx3, rx3) = channel();
  81     let arc3 = arc.clone();
  82     let t3 = thread::spawn(move|| { check_pedigree(arc3); tx3.send(()); });
  83     rx1.recv();
  84     rx2.recv();
  85     rx3.recv();
  86     t1.join();
  87     t2.join();
  88     t3.join();
  89 }
  90
  91 fn check_legs(arc: Arc<Vec<Box<dyn Pet+Sync+Send>>>) {
  92     let mut legs = 0;
  93     for pet in arc.iter() {
  94         legs += pet.num_legs();
  95     }
  96     assert!(legs == 12);
  97 }
  98 fn check_names(arc: Arc<Vec<Box<dyn Pet+Sync+Send>>>) {
  99     for pet in arc.iter() {
 100         pet.name(Box::new(|name| {
 101             assert!(name.as_bytes()[0] == 'a' as u8 && name.as_bytes()[1] == 'l' as u8);
 102         }))
 103     }
 104 }
 105 fn check_pedigree(arc: Arc<Vec<Box<dyn Pet+Sync+Send>>>) {
 106     for pet in arc.iter() {
 107         assert!(pet.of_good_pedigree());
 108     }
 109 }