vm: remove iterator/enumerator Concat API

Follow neo-project/neo#2170.

pkg/compiler/syscall.go

@@ -36,13 +36,11 @@ var syscalls = map[string]map[string]string{
 		"SHA256":                      interopnames.NeoCryptoSHA256,
 	},
 	"enumerator": {
-		"Concat": interopnames.SystemEnumeratorConcat,
 		"Create": interopnames.SystemEnumeratorCreate,
 		"Next":   interopnames.SystemEnumeratorNext,
 		"Value":  interopnames.SystemEnumeratorValue,
 	},
 	"iterator": {
-		"Concat": interopnames.SystemIteratorConcat,
 		"Create": interopnames.SystemIteratorCreate,
 		"Key":    interopnames.SystemIteratorKey,
 		"Keys":   interopnames.SystemIteratorKeys,

pkg/core/interop/enumerator/interop.go

@@ -5,11 +5,6 @@ import (
 	"github.com/nspcc-dev/neo-go/pkg/vm"
 )
 
-// Concat concatenates 2 enumerators into a single one.
-func Concat(ic *interop.Context) error {
-	return vm.EnumeratorConcat(ic.VM)
-}
-
 // Create creates an enumerator from an array-like or bytearray-like stack item.
 func Create(ic *interop.Context) error {
 	return vm.EnumeratorCreate(ic.VM)

pkg/core/interop/enumerator/interop_test.go

@@ -13,11 +13,8 @@ import (
 func TestEnumerator(t *testing.T) {
 	ic := &interop.Context{VM: vm.New()}
 	full := []byte{4, 8, 15}
-	ic.VM.Estack().PushVal(full[2:])
+	ic.VM.Estack().PushVal(full)
 	require.NoError(t, Create(ic))
-	ic.VM.Estack().PushVal(full[:2])
-	require.NoError(t, Create(ic))
-	require.NoError(t, Concat(ic))
 
 	res := ic.VM.Estack().Pop().Item()
 	for i := range full {

pkg/core/interop/interopnames/names.go

@@ -26,11 +26,9 @@ const (
 	SystemContractGetCallFlags               = "System.Contract.GetCallFlags"
 	SystemContractNativeOnPersist            = "System.Contract.NativeOnPersist"
 	SystemContractNativePostPersist          = "System.Contract.NativePostPersist"
-	SystemEnumeratorConcat                   = "System.Enumerator.Concat"
 	SystemEnumeratorCreate                   = "System.Enumerator.Create"
 	SystemEnumeratorNext                     = "System.Enumerator.Next"
 	SystemEnumeratorValue                    = "System.Enumerator.Value"
-	SystemIteratorConcat                     = "System.Iterator.Concat"
 	SystemIteratorCreate                     = "System.Iterator.Create"
 	SystemIteratorKey                        = "System.Iterator.Key"
 	SystemIteratorKeys                       = "System.Iterator.Keys"
@@ -91,11 +89,9 @@ var names = []string{
 	SystemContractGetCallFlags,
 	SystemContractNativeOnPersist,
 	SystemContractNativePostPersist,
-	SystemEnumeratorConcat,
 	SystemEnumeratorCreate,
 	SystemEnumeratorNext,
 	SystemEnumeratorValue,
-	SystemIteratorConcat,
 	SystemIteratorCreate,
 	SystemIteratorKey,
 	SystemIteratorKeys,

pkg/core/interop/iterator/interop.go

@@ -5,11 +5,6 @@ import (
 	"github.com/nspcc-dev/neo-go/pkg/vm"
 )
 
-// Concat concatenates 2 iterators into a single one.
-func Concat(ic *interop.Context) error {
-	return vm.IteratorConcat(ic.VM)
-}
-
 // Create creates an iterator from array-like or map stack item.
 func Create(ic *interop.Context) error {
 	return vm.IteratorCreate(ic.VM)

pkg/core/interop/iterator/interop_test.go

@@ -13,11 +13,8 @@ import (
 func TestIterator(t *testing.T) {
 	ic := &interop.Context{VM: vm.New()}
 	full := []byte{4, 8, 15}
-	ic.VM.Estack().PushVal(full[2:])
+	ic.VM.Estack().PushVal(full)
 	require.NoError(t, Create(ic))
-	ic.VM.Estack().PushVal(full[:2])
-	require.NoError(t, Create(ic))
-	require.NoError(t, Concat(ic))
 
 	res := ic.VM.Estack().Pop().Item()
 	ic.VM.Estack().PushVal(res)

pkg/core/interops.go

@@ -58,11 +58,9 @@ var systemInterops = []interop.Function{
 	{Name: interopnames.SystemContractGetCallFlags, Func: contractGetCallFlags, Price: 1 << 10},
 	{Name: interopnames.SystemContractNativeOnPersist, Func: native.OnPersist, Price: 0, RequiredFlags: callflag.WriteStates},
 	{Name: interopnames.SystemContractNativePostPersist, Func: native.PostPersist, Price: 0, RequiredFlags: callflag.WriteStates},
-	{Name: interopnames.SystemEnumeratorConcat, Func: enumerator.Concat, Price: 1 << 4, ParamCount: 2},
 	{Name: interopnames.SystemEnumeratorCreate, Func: enumerator.Create, Price: 1 << 4, ParamCount: 1},
 	{Name: interopnames.SystemEnumeratorNext, Func: enumerator.Next, Price: 1 << 15, ParamCount: 1},
 	{Name: interopnames.SystemEnumeratorValue, Func: enumerator.Value, Price: 1 << 4, ParamCount: 1},
-	{Name: interopnames.SystemIteratorConcat, Func: iterator.Concat, Price: 1 << 4, ParamCount: 2},
 	{Name: interopnames.SystemIteratorCreate, Func: iterator.Create, Price: 1 << 4, ParamCount: 1},
 	{Name: interopnames.SystemIteratorKey, Func: iterator.Key, Price: 1 << 4, ParamCount: 1},
 	{Name: interopnames.SystemIteratorKeys, Func: iterator.Keys, Price: 1 << 4, ParamCount: 1},

pkg/interop/enumerator/enumerator.go

@@ -30,12 +30,3 @@ func Next(e Enumerator) bool {
 func Value(e Enumerator) interface{} {
 	return nil
 }
-
-// Concat concatenates two given enumerators returning one that will range on
-// a first and then continue with b. Enumerator positions are not reset for a
-// and b, so if any of them was already advanced by Next the resulting
-// Enumerator will point at this new position and never go back to previous
-// values. This function uses `System.Enumerator.Concat` syscall.
-func Concat(a, b Enumerator) Enumerator {
-	return Enumerator{}
-}

pkg/interop/iterator/iterator.go

@@ -19,17 +19,6 @@ func Create(items interface{}) Iterator {
 	return Iterator{}
 }
 
-// Concat concatenates two given iterators returning one that will range on
-// a first and then continue with b. Iterator positions are not reset for a
-// and b, so if any of them was already advanced by Next the resulting
-// Iterator will point at this new position and never go back to previous
-// key-value pairs. Concatenated iterators also remain completely independent
-// in results they return, so if both contain the same key you'll receive this
-// key twice when iterating. This function uses `System.Iterator.Concat` syscall.
-func Concat(a, b Iterator) Iterator {
-	return Iterator{}
-}
-
 // Key returns iterator's key at current position. It's only valid to call after
 // successful Next call. This function uses `System.Iterator.Key` syscall.
 func Key(it Iterator) interface{} {

pkg/vm/interop.go

@@ -31,14 +31,10 @@ var defaultVMInterops = []interopIDFuncPrice{
 		Func: EnumeratorCreate, Price: 1 << 4},
 	{ID: interopnames.ToID([]byte(interopnames.SystemEnumeratorNext)),
 		Func: EnumeratorNext, Price: 1 << 15},
-	{ID: interopnames.ToID([]byte(interopnames.SystemEnumeratorConcat)),
-		Func: EnumeratorConcat, Price: 1 << 4},
 	{ID: interopnames.ToID([]byte(interopnames.SystemEnumeratorValue)),
 		Func: EnumeratorValue, Price: 1 << 4},
 	{ID: interopnames.ToID([]byte(interopnames.SystemIteratorCreate)),
 		Func: IteratorCreate, Price: 1 << 4},
-	{ID: interopnames.ToID([]byte(interopnames.SystemIteratorConcat)),
-		Func: IteratorConcat, Price: 1 << 4},
 	{ID: interopnames.ToID([]byte(interopnames.SystemIteratorKey)),
 		Func: IteratorKey, Price: 1 << 4},
 	{ID: interopnames.ToID([]byte(interopnames.SystemIteratorKeys)),
@@ -160,23 +156,6 @@ func EnumeratorValue(v *VM) error {
 	return nil
 }
 
-// EnumeratorConcat handles syscall System.Enumerator.Concat.
-func EnumeratorConcat(v *VM) error {
-	iop1 := v.Estack().Pop().Interop()
-	arr1 := iop1.Value().(enumerator)
-	iop2 := v.Estack().Pop().Interop()
-	arr2 := iop2.Value().(enumerator)
-
-	v.Estack().Push(&Element{
-		value: stackitem.NewInterop(&concatEnum{
-			current: arr1,
-			second:  arr2,
-		}),
-	})
-
-	return nil
-}
-
 // IteratorCreate handles syscall System.Iterator.Create.
 func IteratorCreate(v *VM) error {
 	data := v.Estack().Pop()
@@ -212,23 +191,6 @@ func NewMapIterator(m *stackitem.Map) *stackitem.Interop {
 	})
 }
 
-// IteratorConcat handles syscall System.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: stackitem.NewInterop(
-		&concatIter{
-			current: iter1,
-			second:  iter2,
-		},
-	)})
-
-	return nil
-}
-
 // IteratorKey handles syscall System.Iterator.Key.
 func IteratorKey(v *VM) error {
 	iop := v.estack.Pop().Interop()

pkg/vm/interop_iterators.go

@@ -22,10 +22,6 @@ type (
 		value []byte
 	}
 
-	concatEnum struct {
-		current enumerator
-		second  enumerator
-	}
 )
 
 type (
@@ -39,11 +35,6 @@ type (
 		m     []stackitem.MapElement
 	}
 
-	concatIter struct {
-		current iterator
-		second  iterator
-	}
-
 	keysWrapper struct {
 		iter iterator
 	}
@@ -87,36 +78,6 @@ func (a *byteArrayWrapper) Key() stackitem.Item {
 	return stackitem.Make(a.index)
 }
 
-func (c *concatEnum) Next() bool {
-	if c.current.Next() {
-		return true
-	}
-	c.current = c.second
-
-	return c.current.Next()
-}
-
-func (c *concatEnum) Value() stackitem.Item {
-	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.Item {
-	return i.current.Value()
-}
-
-func (i *concatIter) Key() stackitem.Item {
-	return i.current.Key()
-}
-
 func (m *mapWrapper) Next() bool {
 	if next := m.index + 1; next < len(m.m) {
 		m.index = next

pkg/vm/vm_test.go

@@ -545,50 +545,6 @@ func TestIteratorCreate(t *testing.T) {
 	})
 }
 
-func testIterableConcat(t *testing.T, typ string) {
-	isIter := typ == "Iterator"
-	prog := getSyscallProg("System." + typ + ".Create")
-	prog = append(prog, byte(opcode.SWAP))
-	prog = append(prog, getSyscallProg("System."+typ+".Create")...)
-	prog = append(prog, getSyscallProg("System."+typ+".Concat")...)
-	prog = append(prog, getEnumeratorProg(3, isIter)...)
-	vm := load(prog)
-
-	arr := []stackitem.Item{
-		stackitem.NewBool(false),
-		stackitem.NewBigInteger(big.NewInt(123)),
-		stackitem.NewMap(),
-	}
-	vm.estack.Push(&Element{value: stackitem.NewArray(arr[:1])})
-	vm.estack.Push(&Element{value: stackitem.NewArray(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.Item{
-			stackitem.Make(1), arr[2], stackitem.NewBool(true),
-			stackitem.Make(0), arr[1], stackitem.NewBool(true),
-			stackitem.Make(0), arr[0], stackitem.NewBool(true),
-		})
-	} else {
-		checkEnumeratorStack(t, vm, []stackitem.Item{
-			arr[2], stackitem.NewBool(true),
-			arr[1], stackitem.NewBool(true),
-			arr[0], stackitem.NewBool(true),
-		})
-	}
-}
-
-func TestEnumeratorConcat(t *testing.T) {
-	testIterableConcat(t, "Enumerator")
-}
-
-func TestIteratorConcat(t *testing.T) {
-	testIterableConcat(t, "Iterator")
-}
-
 func TestIteratorKeys(t *testing.T) {
 	prog := getSyscallProg(interopnames.SystemIteratorCreate)
 	prog = append(prog, getSyscallProg(interopnames.SystemIteratorKeys)...)