puddle/
lib.rs

1use async_std::sync::{Condvar, Mutex};
2
3#[derive(Debug)]
4pub struct Pool<T> {
5    sync_tuple: Mutex<(Vec<T>, usize)>,
6    cvar: Condvar,
7    max: usize,
8}
9
10impl<T> Pool<T> {
11    pub fn new(max: usize) -> Self {
12        Self {
13            sync_tuple: Mutex::new((Vec::new(), 0)),
14            cvar: Condvar::new(),
15            max,
16        }
17    }
18
19    pub async fn put(&self, item: T) {
20        let mut lock_guard = (&self.sync_tuple).lock().await;
21        (*lock_guard).0.push(item);
22        self.cvar.notify_one();
23    }
24
25    pub async fn take<F>(&self, create: F) -> T
26    where
27        F: FnOnce() -> T,
28    {
29        let mut lock_guard = (&self.sync_tuple).lock().await;
30
31        while (*lock_guard).0.is_empty() && (*lock_guard).1 == self.max {
32            lock_guard = self.cvar.wait(lock_guard).await;
33        }
34
35        if (*lock_guard).1 < self.max {
36            (*lock_guard).0.push(create());
37            (*lock_guard).1 += 1;
38        }
39
40        return (*lock_guard).0.remove(0);
41    }
42}
puddle/lib.rs

puddle/
lib.rs
