1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
|
// aux-build:arc_wake.rs
// edition:2018
// run-pass
#![deny(dead_code)]
#![allow(unused_variables)]
#![allow(unused_must_use)]
#![allow(path_statements)]
// Test that the drop order for locals in a fn and async fn matches up.
extern crate arc_wake;
use arc_wake::ArcWake;
use std::cell::RefCell;
use std::future::Future;
use std::pin::Pin;
use std::rc::Rc;
use std::sync::Arc;
use std::task::{Context, Poll};
struct EmptyWaker;
impl ArcWake for EmptyWaker {
fn wake(self: Arc<Self>) {}
}
#[derive(Debug, Eq, PartialEq)]
enum DropOrder {
Function,
Val(&'static str),
}
type DropOrderListPtr = Rc<RefCell<Vec<DropOrder>>>;
struct D(&'static str, DropOrderListPtr);
impl Drop for D {
fn drop(&mut self) {
self.1.borrow_mut().push(DropOrder::Val(self.0));
}
}
struct NeverReady;
impl Future for NeverReady {
type Output = ();
fn poll(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output> {
Poll::Pending
}
}
async fn simple_variable_declaration_async(l: DropOrderListPtr) {
l.borrow_mut().push(DropOrder::Function);
let x = D("x", l.clone());
let y = D("y", l.clone());
NeverReady.await;
}
fn simple_variable_declaration_sync(l: DropOrderListPtr) {
l.borrow_mut().push(DropOrder::Function);
let x = D("x", l.clone());
let y = D("y", l.clone());
}
async fn varable_completely_contained_within_block_async(l: DropOrderListPtr) {
l.borrow_mut().push(DropOrder::Function);
async {
let x = D("x", l.clone());
}
.await;
let y = D("y", l.clone());
NeverReady.await;
}
fn varable_completely_contained_within_block_sync(l: DropOrderListPtr) {
l.borrow_mut().push(DropOrder::Function);
{
let x = D("x", l.clone());
}
let y = D("y", l.clone());
}
async fn variables_moved_into_separate_blocks_async(l: DropOrderListPtr) {
l.borrow_mut().push(DropOrder::Function);
let x = D("x", l.clone());
let y = D("y", l.clone());
async move { x }.await;
async move { y }.await;
NeverReady.await;
}
fn variables_moved_into_separate_blocks_sync(l: DropOrderListPtr) {
l.borrow_mut().push(DropOrder::Function);
let x = D("x", l.clone());
let y = D("y", l.clone());
{
x
};
{
y
};
}
async fn variables_moved_into_same_block_async(l: DropOrderListPtr) {
l.borrow_mut().push(DropOrder::Function);
let x = D("x", l.clone());
let y = D("y", l.clone());
async move {
x;
y;
};
NeverReady.await;
}
fn variables_moved_into_same_block_sync(l: DropOrderListPtr) {
l.borrow_mut().push(DropOrder::Function);
let x = D("x", l.clone());
let y = D("y", l.clone());
{
x;
y;
};
return;
}
async fn move_after_current_await_doesnt_affect_order(l: DropOrderListPtr) {
l.borrow_mut().push(DropOrder::Function);
let x = D("x", l.clone());
let y = D("y", l.clone());
NeverReady.await;
async move {
x;
y;
};
}
fn assert_drop_order_after_cancel<Fut: Future<Output = ()>>(
f: impl FnOnce(DropOrderListPtr) -> Fut,
g: impl FnOnce(DropOrderListPtr),
) {
let empty = Arc::new(EmptyWaker);
let waker = ArcWake::into_waker(empty);
let mut cx = Context::from_waker(&waker);
let actual_order = Rc::new(RefCell::new(Vec::new()));
let mut fut = Box::pin(f(actual_order.clone()));
let _ = fut.as_mut().poll(&mut cx);
drop(fut);
let expected_order = Rc::new(RefCell::new(Vec::new()));
g(expected_order.clone());
assert_eq!(*actual_order.borrow(), *expected_order.borrow());
}
fn main() {
assert_drop_order_after_cancel(
simple_variable_declaration_async,
simple_variable_declaration_sync,
);
assert_drop_order_after_cancel(
varable_completely_contained_within_block_async,
varable_completely_contained_within_block_sync,
);
assert_drop_order_after_cancel(
variables_moved_into_separate_blocks_async,
variables_moved_into_separate_blocks_sync,
);
assert_drop_order_after_cancel(
variables_moved_into_same_block_async,
variables_moved_into_same_block_sync,
);
assert_drop_order_after_cancel(
move_after_current_await_doesnt_affect_order,
simple_variable_declaration_sync,
);
}
|
