lock_and_do.go

package xsync

import "sync"

type TryLocker interface {
  sync.Locker // Lock(); Unlock()
  TryLock() bool
}

// LockAndDo will acquire the lock l and execute fn.
// It will execute fn immediately if the lock was not locked
// when LockAndDo is called, and will execute fn in a goroutine
// otherwise.
// The lock is released once fn has completed execution.
//
// LockAndDo is mostly useful to efficiently execute short,
// non-blocking logic that must be executed protected by a lock
// that may be contended, while avoiding blocking the caller
// of LockAndDo (e.g. because the logic in the callee has lower
// priority compared to the logic executed by the caller).
func LockAndDo(l TryLocker, fn func()) {
	if l.TryLock() {
		defer l.Unlock()
		fn()
		return
	}
	go func() {
		l.Lock()
		defer l.Unlock()
		fn()
	}()
}