mirror of https://github.com/rust-lang/rust
56 lines
1.4 KiB
Rust
56 lines
1.4 KiB
Rust
// Checks for issue #26235
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fn main() {
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use std::thread;
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type Key = u32;
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const NUM_THREADS: usize = 2;
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#[derive(Clone, Copy)]
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struct Stats<S> {
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upsert: S,
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delete: S,
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insert: S,
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update: S,
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};
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impl<S> Stats<S>
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where
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S: Copy,
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{
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fn dot<B, F, T>(self, s: Stats<T>, f: F) -> Stats<B>
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where
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F: Fn(S, T) -> B,
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{
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let Stats { upsert: u1, delete: d1, insert: i1, update: p1 } = self;
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let Stats { upsert: u2, delete: d2, insert: i2, update: p2 } = s;
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Stats { upsert: f(u1, u2), delete: f(d1, d2), insert: f(i1, i2), update: f(p1, p2) }
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}
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fn new(init: S) -> Self {
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Stats { upsert: init, delete: init, insert: init, update: init }
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}
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}
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fn make_threads() -> Vec<thread::JoinHandle<()>> {
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let mut t = Vec::with_capacity(NUM_THREADS);
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for _ in 0..NUM_THREADS {
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t.push(thread::spawn(move || {}));
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}
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t
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}
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let stats = [Stats::new(0); NUM_THREADS];
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make_threads();
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{
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let Stats { ref upsert, ref delete, ref insert, ref update } = stats
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.iter()
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.fold(Stats::new(0), |res, &s| res.dot(s, |x: Key, y: Key| x.wrapping_add(y)));
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println!(
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"upserts: {}, deletes: {}, inserts: {}, updates: {}",
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upsert, delete, insert, update
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);
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}
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}
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