effect/default_effector_stream.go

package effect

// DefaultEffectorStream is the default implementation of interface EffectorStream.
type DefaultEffectorStream struct {
	done bool
	res  bool
	expr string
	idx  int
	cap  int
	expl []int
}

func pushIndex(truthValue bool, s *[]int, index int) {
	if truthValue {
		*s = append(*s, index)
	}
}

func (s *DefaultEffectorStream) Next() bool {
	if !s.done {
		panic("done should be true")
	}
	return s.res
}

func (s *DefaultEffectorStream) Explain() []int {
	if !s.done {
		panic("done should be true")
	}
	return s.expl
}

func (s *DefaultEffectorStream) PushEffect(eft Effect) bool {
	hasPolicy := s.cap > 1

	if s.expr == "some(where (p_eft == allow))" {
		if eft == Allow {
			s.done = true
			s.res = true
			pushIndex(hasPolicy, &s.expl, s.idx)
		}
	} else if s.expr == "some(where (p_eft == allow)) && !some(where (p_eft == deny))" {
		if eft == Allow {
			s.res = true
			pushIndex(hasPolicy, &s.expl, s.idx)
		} else if eft == Deny {
			s.done = true
			s.res = false
			pushIndex(hasPolicy, &s.expl, s.idx)
		}
	} else if s.expr == "!some(where (p_eft == deny))" {
		if eft == Deny {
			s.done = true
			s.res = false
			pushIndex(hasPolicy, &s.expl, s.idx)
		}
	} else if s.expr == "priority(p_eft) || deny" && eft != Indeterminate {
		s.res = eft == Allow
		s.done = true
		pushIndex(hasPolicy, &s.expl, s.idx)
	}

	if s.idx+1 == s.cap {
		s.done = true
	}
	s.idx++

	return s.done
}