vm: implement Neo.Iterator.* interops

pkg/core/interop_neo.go

@@ -808,3 +808,28 @@ func (ic *interopContext) enumeratorNext(v *vm.VM) error {
 func (ic *interopContext) enumeratorValue(v *vm.VM) error {
 	return vm.EnumeratorValue(v)
 }
+
+// iteratorConcat concatenates 2 iterators into a single one.
+func (ic *interopContext) iteratorConcat(v *vm.VM) error {
+	return vm.IteratorConcat(v)
+}
+
+// iteratorCreate creates an iterator from array-like or map stack item.
+func (ic *interopContext) iteratorCreate(v *vm.VM) error {
+	return vm.IteratorCreate(v)
+}
+
+// iteratorKey returns current iterator key.
+func (ic *interopContext) iteratorKey(v *vm.VM) error {
+	return vm.IteratorKey(v)
+}
+
+// iteratorKeys returns keys of the iterator.
+func (ic *interopContext) iteratorKeys(v *vm.VM) error {
+	return vm.IteratorKeys(v)
+}
+
+// iteratorValues returns values of the iterator.
+func (ic *interopContext) iteratorValues(v *vm.VM) error {
+	return vm.IteratorValues(v)
+}

pkg/core/interops.go

@@ -157,6 +157,11 @@ var neoInterops = []interopedFunction{
 	{Name: "Neo.Input.GetHash", Func: (*interopContext).inputGetHash, Price: 1},
 	{Name: "Neo.Input.GetIndex", Func: (*interopContext).inputGetIndex, Price: 1},
 	{Name: "Neo.InvocationTransaction.GetScript", Func: (*interopContext).invocationTxGetScript, Price: 1},
+	{Name: "Neo.Iterator.Concat", Func: (*interopContext).iteratorConcat, Price: 1},
+	{Name: "Neo.Iterator.Create", Func: (*interopContext).iteratorCreate, Price: 1},
+	{Name: "Neo.Iterator.Key", Func: (*interopContext).iteratorKey, Price: 1},
+	{Name: "Neo.Iterator.Keys", Func: (*interopContext).iteratorKeys, Price: 1},
+	{Name: "Neo.Iterator.Values", Func: (*interopContext).iteratorValues, Price: 1},
 	{Name: "Neo.Output.GetAssetId", Func: (*interopContext).outputGetAssetID, Price: 1},
 	{Name: "Neo.Output.GetScriptHash", Func: (*interopContext).outputGetScriptHash, Price: 1},
 	{Name: "Neo.Output.GetValue", Func: (*interopContext).outputGetValue, Price: 1},
@@ -182,16 +187,11 @@ var neoInterops = []interopedFunction{
 	{Name: "Neo.Transaction.GetUnspentCoins", Func: (*interopContext).txGetUnspentCoins, Price: 200},
 	{Name: "Neo.Transaction.GetWitnesses", Func: (*interopContext).txGetWitnesses, Price: 200},
 	{Name: "Neo.Witness.GetVerificationScript", Func: (*interopContext).witnessGetVerificationScript, Price: 100},
-	//		{Name: "Neo.Iterator.Concat", Func: (*interopContext).iteratorConcat, Price: 1},
-	//		{Name: "Neo.Iterator.Create", Func: (*interopContext).iteratorCreate, Price: 1},
-	//		{Name: "Neo.Iterator.Key", Func: (*interopContext).iteratorKey, Price: 1},
-	//		{Name: "Neo.Iterator.Keys", Func: (*interopContext).iteratorKeys, Price: 1},
-	//		{Name: "Neo.Iterator.Values", Func: (*interopContext).iteratorValues, Price: 1},
 	//		{Name: "Neo.Storage.Find",                Func: (*interopContext).storageFind, Price: 1},
 
 	// Aliases.
-	//		{Name: "Neo.Iterator.Next", Func: (*interopContext).enumeratorNext, Price: 1},
+	{Name: "Neo.Iterator.Next", Func: (*interopContext).enumeratorNext, Price: 1},
-	//		{Name: "Neo.Iterator.Value", Func: (*interopContext).enumeratorValue, Price: 1},
+	{Name: "Neo.Iterator.Value", Func: (*interopContext).enumeratorValue, Price: 1},
 
 	// Old compatibility APIs.
 	{Name: "AntShares.Account.GetBalance", Func: (*interopContext).accountGetBalance, Price: 1},

pkg/vm/interop.go

@@ -48,6 +48,16 @@ var defaultVMInterops = []interopIDFuncPrice{
 		InteropFuncPrice{EnumeratorConcat, 1}},
 	{InteropNameToID([]byte("Neo.Enumerator.Value")),
 		InteropFuncPrice{EnumeratorValue, 1}},
+	{InteropNameToID([]byte("Neo.Iterator.Create")),
+		InteropFuncPrice{IteratorCreate, 1}},
+	{InteropNameToID([]byte("Neo.Iterator.Concat")),
+		InteropFuncPrice{IteratorConcat, 1}},
+	{InteropNameToID([]byte("Neo.Iterator.Key")),
+		InteropFuncPrice{IteratorKey, 1}},
+	{InteropNameToID([]byte("Neo.Iterator.Keys")),
+		InteropFuncPrice{IteratorKeys, 1}},
+	{InteropNameToID([]byte("Neo.Iterator.Values")),
+		InteropFuncPrice{IteratorValues, 1}},
 }
 
 func getDefaultVMInterop(id uint32) *InteropFuncPrice {
@@ -163,3 +173,80 @@ func EnumeratorConcat(v *VM) error {
 
 	return nil
 }
+
+// IteratorCreate handles syscall Neo.Iterator.Create.
+func IteratorCreate(v *VM) error {
+	data := v.Estack().Pop()
+	var item interface{}
+	switch t := data.value.(type) {
+	case *ArrayItem, *StructItem:
+		item = &arrayWrapper{
+			index: -1,
+			value: t.Value().([]StackItem),
+		}
+	case *MapItem:
+		keys := make([]interface{}, 0, len(t.value))
+		for k := range t.value {
+			keys = append(keys, k)
+		}
+
+		item = &mapWrapper{
+			index: -1,
+			keys:  keys,
+			m:     t.value,
+		}
+	default:
+		return errors.New("non-iterable type")
+	}
+
+	v.Estack().Push(&Element{value: NewInteropItem(item)})
+	return nil
+}
+
+// IteratorConcat handles syscall Neo.Iterator.Concat.
+func IteratorConcat(v *VM) error {
+	iop1 := v.Estack().Pop().Interop()
+	iter1 := iop1.value.(iterator)
+	iop2 := v.Estack().Pop().Interop()
+	iter2 := iop2.value.(iterator)
+
+	v.Estack().Push(&Element{value: NewInteropItem(
+		&concatIter{
+			current: iter1,
+			second:  iter2,
+		},
+	)})
+
+	return nil
+}
+
+// IteratorKey handles syscall Neo.Iterator.Key.
+func IteratorKey(v *VM) error {
+	iop := v.estack.Pop().Interop()
+	iter := iop.value.(iterator)
+	v.Estack().Push(&Element{value: iter.Key()})
+
+	return nil
+}
+
+// IteratorKeys handles syscall Neo.Iterator.Keys.
+func IteratorKeys(v *VM) error {
+	iop := v.estack.Pop().Interop()
+	iter := iop.value.(iterator)
+	v.Estack().Push(&Element{value: NewInteropItem(
+		&keysWrapper{iter},
+	)})
+
+	return nil
+}
+
+// IteratorValues handles syscall Neo.Iterator.Values.
+func IteratorValues(v *VM) error {
+	iop := v.estack.Pop().Interop()
+	iter := iop.value.(iterator)
+	v.Estack().Push(&Element{value: NewInteropItem(
+		&valuesWrapper{iter},
+	)})
+
+	return nil
+}

pkg/vm/interop_iterators.go

@@ -17,6 +17,32 @@ type (
 	}
 )
 
+type (
+	iterator interface {
+		enumerator
+		Key() StackItem
+	}
+
+	mapWrapper struct {
+		index int
+		keys  []interface{}
+		m     map[interface{}]StackItem
+	}
+
+	concatIter struct {
+		current iterator
+		second  iterator
+	}
+
+	keysWrapper struct {
+		iter iterator
+	}
+
+	valuesWrapper struct {
+		iter iterator
+	}
+)
+
 func (a *arrayWrapper) Next() bool {
 	if next := a.index + 1; next < len(a.value) {
 		a.index = next
@@ -30,6 +56,10 @@ func (a *arrayWrapper) Value() StackItem {
 	return a.value[a.index]
 }
 
+func (a *arrayWrapper) Key() StackItem {
+	return makeStackItem(a.index)
+}
+
 func (c *concatEnum) Next() bool {
 	if c.current.Next() {
 		return true
@@ -42,3 +72,53 @@ func (c *concatEnum) Next() bool {
 func (c *concatEnum) Value() StackItem {
 	return c.current.Value()
 }
+
+func (i *concatIter) Next() bool {
+	if i.current.Next() {
+		return true
+	}
+	i.current = i.second
+
+	return i.second.Next()
+}
+
+func (i *concatIter) Value() StackItem {
+	return i.current.Value()
+}
+
+func (i *concatIter) Key() StackItem {
+	return i.current.Key()
+}
+
+func (m *mapWrapper) Next() bool {
+	if next := m.index + 1; next < len(m.keys) {
+		m.index = next
+		return true
+	}
+
+	return false
+}
+
+func (m *mapWrapper) Value() StackItem {
+	return m.m[m.keys[m.index]]
+}
+
+func (m *mapWrapper) Key() StackItem {
+	return makeStackItem(m.keys[m.index])
+}
+
+func (e *keysWrapper) Next() bool {
+	return e.iter.Next()
+}
+
+func (e *keysWrapper) Value() StackItem {
+	return e.iter.Key()
+}
+
+func (e *valuesWrapper) Next() bool {
+	return e.iter.Next()
+}
+
+func (e *valuesWrapper) Value() StackItem {
+	return e.iter.Value()
+}

pkg/vm/vm_test.go

@@ -333,13 +333,17 @@ func TestPushData4Good(t *testing.T) {
 	assert.Equal(t, []byte{1, 2, 3}, vm.estack.Pop().Bytes())
 }
 
-func getEnumeratorProg(n int) (prog []byte) {
+func getEnumeratorProg(n int, isIter bool) (prog []byte) {
 	prog = append(prog, byte(opcode.TOALTSTACK))
 	for i := 0; i < n; i++ {
 		prog = append(prog, byte(opcode.DUPFROMALTSTACK))
 		prog = append(prog, getSyscallProg("Neo.Enumerator.Next")...)
 		prog = append(prog, byte(opcode.DUPFROMALTSTACK))
 		prog = append(prog, getSyscallProg("Neo.Enumerator.Value")...)
+		if isIter {
+			prog = append(prog, byte(opcode.DUPFROMALTSTACK))
+			prog = append(prog, getSyscallProg("Neo.Iterator.Key")...)
+		}
 	}
 	prog = append(prog, byte(opcode.DUPFROMALTSTACK))
 	prog = append(prog, getSyscallProg("Neo.Enumerator.Next")...)
@@ -356,8 +360,9 @@ func checkEnumeratorStack(t *testing.T, vm *VM, arr []StackItem) {
 }
 
 func testIterableCreate(t *testing.T, typ string) {
+	isIter := typ == "Iterator"
 	prog := getSyscallProg("Neo." + typ + ".Create")
-	prog = append(prog, getEnumeratorProg(2)...)
+	prog = append(prog, getEnumeratorProg(2, isIter)...)
 
 	vm := load(prog)
 	arr := []StackItem{
@@ -367,22 +372,34 @@ func testIterableCreate(t *testing.T, typ string) {
 	vm.estack.Push(&Element{value: NewArrayItem(arr)})
 
 	runVM(t, vm)
+	if isIter {
+		checkEnumeratorStack(t, vm, []StackItem{
+			makeStackItem(1), arr[1], NewBoolItem(true),
+			makeStackItem(0), arr[0], NewBoolItem(true),
+		})
+	} else {
 		checkEnumeratorStack(t, vm, []StackItem{
 			arr[1], NewBoolItem(true),
 			arr[0], NewBoolItem(true),
 		})
 	}
+}
 
 func TestEnumeratorCreate(t *testing.T) {
 	testIterableCreate(t, "Enumerator")
 }
 
-func TestEnumeratorConcat(t *testing.T) {
+func TestIteratorCreate(t *testing.T) {
-	prog := getSyscallProg("Neo.Enumerator.Create")
+	testIterableCreate(t, "Iterator")
+}
+
+func testIterableConcat(t *testing.T, typ string) {
+	isIter := typ == "Iterator"
+	prog := getSyscallProg("Neo." + typ + ".Create")
 	prog = append(prog, byte(opcode.SWAP))
-	prog = append(prog, getSyscallProg("Neo.Enumerator.Create")...)
+	prog = append(prog, getSyscallProg("Neo."+typ+".Create")...)
-	prog = append(prog, getSyscallProg("Neo.Enumerator.Concat")...)
+	prog = append(prog, getSyscallProg("Neo."+typ+".Concat")...)
-	prog = append(prog, getEnumeratorProg(3)...)
+	prog = append(prog, getEnumeratorProg(3, isIter)...)
 	vm := load(prog)
 
 	arr := []StackItem{
@@ -394,12 +411,81 @@ func TestEnumeratorConcat(t *testing.T) {
 	vm.estack.Push(&Element{value: NewArrayItem(arr[1:])})
 
 	runVM(t, vm)
+
+	if isIter {
+		// Yes, this is how iterators are concatenated in reference VM
+		// https://github.com/neo-project/neo/blob/master-2.x/neo.UnitTests/UT_ConcatenatedIterator.cs#L54
+		checkEnumeratorStack(t, vm, []StackItem{
+			makeStackItem(1), arr[2], NewBoolItem(true),
+			makeStackItem(0), arr[1], NewBoolItem(true),
+			makeStackItem(0), arr[0], NewBoolItem(true),
+		})
+	} else {
 		checkEnumeratorStack(t, vm, []StackItem{
 			arr[2], NewBoolItem(true),
 			arr[1], NewBoolItem(true),
 			arr[0], NewBoolItem(true),
 		})
 	}
+}
+
+func TestEnumeratorConcat(t *testing.T) {
+	testIterableConcat(t, "Enumerator")
+}
+
+func TestIteratorConcat(t *testing.T) {
+	testIterableConcat(t, "Iterator")
+}
+
+func TestIteratorKeys(t *testing.T) {
+	prog := getSyscallProg("Neo.Iterator.Create")
+	prog = append(prog, getSyscallProg("Neo.Iterator.Keys")...)
+	prog = append(prog, byte(opcode.TOALTSTACK), byte(opcode.DUPFROMALTSTACK))
+	prog = append(prog, getEnumeratorProg(2, false)...)
+
+	v := load(prog)
+	arr := NewArrayItem([]StackItem{
+		NewBoolItem(false),
+		NewBigIntegerItem(42),
+	})
+	v.estack.PushVal(arr)
+
+	runVM(t, v)
+
+	checkEnumeratorStack(t, v, []StackItem{
+		NewBigIntegerItem(1), NewBoolItem(true),
+		NewBigIntegerItem(0), NewBoolItem(true),
+	})
+}
+
+func TestIteratorValues(t *testing.T) {
+	prog := getSyscallProg("Neo.Iterator.Create")
+	prog = append(prog, getSyscallProg("Neo.Iterator.Values")...)
+	prog = append(prog, byte(opcode.TOALTSTACK), byte(opcode.DUPFROMALTSTACK))
+	prog = append(prog, getEnumeratorProg(2, false)...)
+
+	v := load(prog)
+	m := NewMapItem()
+	m.Add(NewBigIntegerItem(1), NewBoolItem(false))
+	m.Add(NewByteArrayItem([]byte{32}), NewByteArrayItem([]byte{7}))
+	v.estack.PushVal(m)
+
+	runVM(t, v)
+	require.Equal(t, 5, v.estack.Len())
+	require.Equal(t, NewBoolItem(false), v.estack.Peek(0).value)
+
+	// Map values can be enumerated in any order.
+	i1, i2 := 1, 3
+	if _, ok := v.estack.Peek(i1).value.(*BoolItem); !ok {
+		i1, i2 = i2, i1
+	}
+
+	require.Equal(t, NewBoolItem(false), v.estack.Peek(i1).value)
+	require.Equal(t, NewByteArrayItem([]byte{7}), v.estack.Peek(i2).value)
+
+	require.Equal(t, NewBoolItem(true), v.estack.Peek(2).value)
+	require.Equal(t, NewBoolItem(true), v.estack.Peek(4).value)
+}
 
 func getSyscallProg(name string) (prog []byte) {
 	prog = []byte{byte(opcode.SYSCALL)}