You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
57 lines
1.4 KiB
Go
57 lines
1.4 KiB
Go
package syncx
|
|
|
|
import "sync"
|
|
|
|
type (
|
|
// LockedCalls makes sure the calls with the same key to be called sequentially.
|
|
// For example, A called F, before it's done, B called F, then B's call would not blocked,
|
|
// after A's call finished, B's call got executed.
|
|
// The calls with the same key are independent, not sharing the returned values.
|
|
// A ------->calls F with key and executes<------->returns
|
|
// B ------------------>calls F with key<--------->executes<---->returns
|
|
LockedCalls interface {
|
|
Do(key string, fn func() (interface{}, error)) (interface{}, error)
|
|
}
|
|
|
|
lockedGroup struct {
|
|
mu sync.Mutex
|
|
m map[string]*sync.WaitGroup
|
|
}
|
|
)
|
|
|
|
func NewLockedCalls() LockedCalls {
|
|
return &lockedGroup{
|
|
m: make(map[string]*sync.WaitGroup),
|
|
}
|
|
}
|
|
|
|
func (lg *lockedGroup) Do(key string, fn func() (interface{}, error)) (interface{}, error) {
|
|
begin:
|
|
lg.mu.Lock()
|
|
if wg, ok := lg.m[key]; ok {
|
|
lg.mu.Unlock()
|
|
wg.Wait()
|
|
goto begin
|
|
}
|
|
|
|
return lg.makeCall(key, fn)
|
|
}
|
|
|
|
func (lg *lockedGroup) makeCall(key string, fn func() (interface{}, error)) (interface{}, error) {
|
|
var wg sync.WaitGroup
|
|
wg.Add(1)
|
|
lg.m[key] = &wg
|
|
lg.mu.Unlock()
|
|
|
|
defer func() {
|
|
// delete key first, done later. can't reverse the order, because if reverse,
|
|
// another Do call might wg.Wait() without get notified with wg.Done()
|
|
lg.mu.Lock()
|
|
delete(lg.m, key)
|
|
lg.mu.Unlock()
|
|
wg.Done()
|
|
}()
|
|
|
|
return fn()
|
|
}
|