neo-go/pkg/vm/ref_counter.go

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package vm
import (
"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
)
// refCounter represents reference counter for the VM.
type refCounter int
type (
rcInc interface {
IncRC() int
}
rcDec interface {
DecRC() int
}
)
func newRefCounter() *refCounter {
return new(refCounter)
}
// Add adds an item to the reference counter.
func (r *refCounter) Add(item stackitem.Item) {
if r == nil {
return
}
*r++
irc, ok := item.(rcInc)
if !ok || irc.IncRC() > 1 {
return
}
switch t := item.(type) {
case *stackitem.Array, *stackitem.Struct:
for _, it := range item.Value().([]stackitem.Item) {
r.Add(it)
}
case *stackitem.Map:
for i := range t.Value().([]stackitem.MapElement) {
r.Add(t.Value().([]stackitem.MapElement)[i].Value)
}
}
}
// Remove removes item from the reference counter.
func (r *refCounter) Remove(item stackitem.Item) {
if r == nil {
return
}
*r--
irc, ok := item.(rcDec)
if !ok || irc.DecRC() > 0 {
return
}
switch t := item.(type) {
case *stackitem.Array, *stackitem.Struct:
for _, it := range item.Value().([]stackitem.Item) {
r.Remove(it)
}
case *stackitem.Map:
for i := range t.Value().([]stackitem.MapElement) {
r.Remove(t.Value().([]stackitem.MapElement)[i].Value)
}
}
}