blob: 6b9fdaabe0cfee17a3860ee48f195a4459ede2cf (
plain)
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
|
import context
// This example demonstrates the use of a cancelable context to prevent a
// routine leak. By the end of the example function, the routine started
// by gen will return without leaking.
fn test_with_cancel() {
// gen generates integers in a separate routine and
// sends them to the returned channel.
// The callers of gen need to cancel the context once
// they are done consuming generated integers not to leak
// the internal routine started by gen.
gen := fn (ctx context.Context) chan int {
dst := chan int{}
go fn (ctx context.Context, dst chan int) {
mut v := 0
ch := ctx.done()
for {
select {
_ := <-ch {
// returning not to leak the routine
return
}
dst <- v {
v++
}
}
}
}(ctx, dst)
return dst
}
ctx := context.with_cancel(context.background())
defer {
context.cancel(ctx)
}
ch := gen(ctx)
for i in 0 .. 5 {
v := <-ch
assert i == v
}
}
|
