sync: add sync.ManyTimes (#12729)

pull/12734/head^2
Taillook 2021-12-06 02:44:25 +09:00 committed by GitHub
parent ae2ae6e6fd
commit 7d1dec5b44
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3 changed files with 86 additions and 0 deletions

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@ -115,6 +115,7 @@ const (
'vlib/vweb/request_test.v', 'vlib/vweb/request_test.v',
'vlib/net/http/request_test.v', 'vlib/net/http/request_test.v',
'vlib/vweb/route_test.v', 'vlib/vweb/route_test.v',
'vlib/sync/many_times_test.v',
'vlib/sync/once_test.v', 'vlib/sync/once_test.v',
] ]
skip_on_non_windows = [ skip_on_non_windows = [

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@ -0,0 +1,36 @@
module sync
import sync.atomic2
pub struct ManyTimes {
mut:
m RwMutex
pub:
times u64 = 1
count u64
}
// new_many_times return a new ManyTimes struct.
pub fn new_many_times(times u64) &ManyTimes {
mut many_times := &ManyTimes{
times: times
}
many_times.m.init()
return many_times
}
// do execute the function only setting times.
pub fn (mut m ManyTimes) do(f fn ()) {
if atomic2.load_u64(&m.count) < m.times {
m.do_slow(f)
}
}
fn (mut m ManyTimes) do_slow(f fn ()) {
m.m.@lock()
if m.count < m.times {
atomic2.store_u64(&m.count, m.count + 1)
f()
}
m.m.unlock()
}

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@ -0,0 +1,49 @@
import sync
struct Counter {
pub mut:
i int
}
fn (mut c Counter) add(i int) {
c.i = c.i + i
}
fn run(mut m sync.ManyTimes, mut co Counter, c chan bool) {
m.do(fn [mut co] () {
co.add(5)
})
c <- true
}
fn test_many_times_once() {
mut co := &Counter{}
mut m := sync.new_many_times(1)
c := chan bool{}
n := 10
// It is executed 10 times, but only once actually.
for i := 0; i < n; i++ {
go run(mut m, mut co, c)
}
for i := 0; i < n; i++ {
<-c
}
assert co.i == 5
}
fn test_many_times_fifth() {
mut co := &Counter{}
mut m := sync.new_many_times(5)
c := chan bool{}
n := 10
// It is executed 10 times, but only 5 times actually.
for i := 0; i < n; i++ {
go run(mut m, mut co, c)
}
for i := 0; i < n; i++ {
<-c
}
assert co.i == 25
}