package release

import "sync"

var (
	sharedMu       sync.Mutex
	sharedRatchets = map[string]*DigestRatchet{}
)

// SharedDigestRatchet is the process's one ratchet for marks written under
// own (Astra I2 #1): every pass, materialization, held stage and static read
// in this process gets the same object, so a channel remembered after a mark
// could not be persisted stays remembered. require, once on, stays on.
func SharedDigestRatchet(own string, also []string, require bool) *DigestRatchet {
	sharedMu.Lock()
	defer sharedMu.Unlock()
	r, ok := sharedRatchets[own]
	if !ok {
		r = NewDigestRatchet(own, also, require)
		sharedRatchets[own] = r
		return r
	}
	if require {
		r.require.Store(true) // atomic: Admit may be reading it right now (Astra I3 #7)
	}
	return r
}