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