sync/waitgroup: backport from master #320

Merged
vtolstov merged 1 commits from waitgroup into v3 2024-03-09 23:37:41 +03:00
2 changed files with 106 additions and 0 deletions
Showing only changes of commit 2cc004b01c - Show all commits

69
sync/waitgroup.go Normal file
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package sync
import (
"context"
"sync"
)
type WaitGroup struct {
wg *sync.WaitGroup
c int
mu sync.Mutex
}
func WrapWaitGroup(wg *sync.WaitGroup) *WaitGroup {
g := &WaitGroup{
wg: wg,
}
return g
}
func NewWaitGroup() *WaitGroup {
var wg sync.WaitGroup
return WrapWaitGroup(&wg)
}
func (g *WaitGroup) Add(n int) {
g.mu.Lock()
g.c += n
g.wg.Add(n)
g.mu.Unlock()
}
func (g *WaitGroup) Done() {
g.mu.Lock()
g.c += -1
g.wg.Add(-1)
g.mu.Unlock()
}
func (g *WaitGroup) Wait() {
g.wg.Wait()
}
func (g *WaitGroup) WaitContext(ctx context.Context) {
done := make(chan struct{})
go func() {
g.wg.Wait()
close(done)
}()
select {
case <-ctx.Done():
g.mu.Lock()
g.wg.Add(-g.c)
<-done
g.wg.Add(g.c)
g.mu.Unlock()
return
case <-done:
return
}
}
func (g *WaitGroup) Waiters() int {
g.mu.Lock()
c := g.c
g.mu.Unlock()
return c
}

37
sync/waitgroup_test.go Normal file
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package sync
import (
"context"
"testing"
"time"
)
func TestWaitGroupContext(t *testing.T) {
wg := NewWaitGroup()
_ = t
wg.Add(1)
ctx, cancel := context.WithTimeout(context.TODO(), 1*time.Second)
defer cancel()
wg.WaitContext(ctx)
}
func TestWaitGroupReuse(t *testing.T) {
wg := NewWaitGroup()
defer func() {
if wg.Waiters() != 0 {
t.Fatal("lost goroutines")
}
}()
wg.Add(1)
defer wg.Done()
ctx, cancel := context.WithTimeout(context.TODO(), 1*time.Second)
defer cancel()
wg.WaitContext(ctx)
wg.Add(1)
defer wg.Done()
ctx, cancel = context.WithTimeout(context.TODO(), 1*time.Second)
defer cancel()
wg.WaitContext(ctx)
}