Merge pull request #979 from nspcc-dev/fix/state

core: make GetUnspentCoins interop return array, fix #978.

pkg/compiler/syscall.go

@@ -69,6 +69,7 @@ var syscalls = map[string]map[string]string{
 		"GetReferences":   "Neo.Transaction.GetReferences",
 		"GetScript":       "Neo.InvocationTransaction.GetScript",
 		"GetType":         "Neo.Transaction.GetType",
+		"GetUnspentCoins": "Neo.Transaction.GetUnspentCoins",
 		"GetWitnesses":    "Neo.Transaction.GetWitnesses",
 	},
 	"asset": {

pkg/core/interop_neo.go

@@ -7,6 +7,7 @@ import (
 	"math"
 
 	"github.com/nspcc-dev/neo-go/pkg/core/state"
+	"github.com/nspcc-dev/neo-go/pkg/core/storage"
 	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
 	"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
 	"github.com/nspcc-dev/neo-go/pkg/smartcontract"
@@ -177,10 +178,20 @@ func (ic *interopContext) txGetUnspentCoins(v *vm.VM) error {
 		return errors.New("value is not a transaction")
 	}
 	ucs, err := ic.dao.GetUnspentCoinState(tx.Hash())
-	if err != nil {
+	if err == storage.ErrKeyNotFound {
+		v.Estack().PushVal([]vm.StackItem{})
+		return nil
+	} else if err != nil {
 		return errors.New("no unspent coin state found")
 	}
-	v.Estack().PushVal(vm.NewInteropItem(ucs))
+
+	items := make([]vm.StackItem, 0, len(ucs.States))
+	for i := range items {
+		if ucs.States[i].State&state.CoinSpent == 0 {
+			items = append(items, vm.NewInteropItem(&ucs.States[i].Output))
+		}
+	}
+	v.Estack().PushVal(items)
 	return nil
 }
 

pkg/interop/transaction/transaction.go

@@ -53,6 +53,12 @@ func GetReferences(t Transaction) []interface{} {
 	return []interface{}{}
 }
 
+// GetUnspentCoins returns a slice of not yet spent ouputs of a given transaction.
+// This function uses `Neo.Transaction.GetUnspentCoint` syscall.
+func GetUnspentCoins(t Transaction) []output.Output {
+	return []output.Output{}
+}
+
 // GetInputs returns a slice of inputs of a given Transaction. Refer to input
 // package on how to use them. This function uses `Neo.Transaction.GetInputs`
 // syscall.