From efad66aee16ab62932e213868eb71f8b0a110f06 Mon Sep 17 00:00:00 2001
From: Evgenii Stratonikov <evgeniy@nspcc.ru>
Date: Sun, 5 Apr 2020 18:05:40 +0300
Subject: [PATCH] compiler: make Notify accept varargs

---
 pkg/compiler/codegen.go      | 10 ++++++++--
 pkg/compiler/syscall_test.go | 25 +++++++++++++++++++++++++
 pkg/compiler/vm_test.go      | 14 +++++++++++++-
 3 files changed, 46 insertions(+), 3 deletions(-)

diff --git a/pkg/compiler/codegen.go b/pkg/compiler/codegen.go
index ddd07a48e..fc4b49893 100644
--- a/pkg/compiler/codegen.go
+++ b/pkg/compiler/codegen.go
@@ -662,7 +662,7 @@ func (c *codegen) Visit(node ast.Node) ast.Visitor {
 			// We can be sure builtins are of type *ast.Ident.
 			c.convertBuiltin(n)
 		case isSyscall(f):
-			c.convertSyscall(f.selector.Name, f.name)
+			c.convertSyscall(n, f.selector.Name, f.name)
 		default:
 			emit.Call(c.prog.BinWriter, opcode.CALL, f.label)
 		}
@@ -978,12 +978,18 @@ func (c *codegen) getByteArray(expr ast.Expr) []byte {
 	}
 }
 
-func (c *codegen) convertSyscall(api, name string) {
+func (c *codegen) convertSyscall(expr *ast.CallExpr, api, name string) {
 	api, ok := syscalls[api][name]
 	if !ok {
 		c.prog.Err = fmt.Errorf("unknown VM syscall api: %s", name)
 		return
 	}
+	switch name {
+	case "Notify":
+		numArgs := len(expr.Args)
+		emit.Int(c.prog.BinWriter, int64(numArgs))
+		emit.Opcode(c.prog.BinWriter, opcode.PACK)
+	}
 	emit.Syscall(c.prog.BinWriter, api)
 
 	// This NOP instruction is basically not needed, but if we do, we have a
diff --git a/pkg/compiler/syscall_test.go b/pkg/compiler/syscall_test.go
index e60544fb5..1eaa53752 100644
--- a/pkg/compiler/syscall_test.go
+++ b/pkg/compiler/syscall_test.go
@@ -2,6 +2,10 @@ package compiler_test
 
 import (
 	"testing"
+
+	"github.com/nspcc-dev/neo-go/pkg/vm"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func TestStoragePutGet(t *testing.T) {
@@ -20,3 +24,24 @@ func TestStoragePutGet(t *testing.T) {
 	`
 	eval(t, src, []byte("foo"))
 }
+
+func TestNotify(t *testing.T) {
+	src := `package foo
+	import "github.com/nspcc-dev/neo-go/pkg/interop/runtime"
+	func Main(arg int) {
+		runtime.Notify(arg, "sum", arg+1)
+		runtime.Notify()
+		runtime.Notify("single")
+	}`
+
+	v, s := vmAndCompileInterop(t, src)
+	v.Estack().PushVal(11)
+
+	require.NoError(t, v.Run())
+	require.Equal(t, 3, len(s.events))
+
+	exp0 := []vm.StackItem{vm.NewBigIntegerItem(11), vm.NewByteArrayItem([]byte("sum")), vm.NewBigIntegerItem(12)}
+	assert.Equal(t, exp0, s.events[0].Value())
+	assert.Equal(t, []vm.StackItem{}, s.events[1].Value())
+	assert.Equal(t, []vm.StackItem{vm.NewByteArrayItem([]byte("single"))}, s.events[2].Value())
+}
diff --git a/pkg/compiler/vm_test.go b/pkg/compiler/vm_test.go
index 6d9d81e26..b97d14acd 100644
--- a/pkg/compiler/vm_test.go
+++ b/pkg/compiler/vm_test.go
@@ -53,6 +53,11 @@ func assertResult(t *testing.T, vm *vm.VM, result interface{}) {
 }
 
 func vmAndCompile(t *testing.T, src string) *vm.VM {
+	v, _ := vmAndCompileInterop(t, src)
+	return v
+}
+
+func vmAndCompileInterop(t *testing.T, src string) (*vm.VM, *storagePlugin) {
 	vm := vm.New()
 
 	storePlugin := newStoragePlugin()
@@ -61,12 +66,13 @@ func vmAndCompile(t *testing.T, src string) *vm.VM {
 	b, err := compiler.Compile(strings.NewReader(src))
 	require.NoError(t, err)
 	vm.Load(b)
-	return vm
+	return vm, storePlugin
 }
 
 type storagePlugin struct {
 	mem      map[string][]byte
 	interops map[uint32]vm.InteropFunc
+	events   []vm.StackItem
 }
 
 func newStoragePlugin() *storagePlugin {
@@ -77,6 +83,7 @@ func newStoragePlugin() *storagePlugin {
 	s.interops[vm.InteropNameToID([]byte("Neo.Storage.Get"))] = s.Get
 	s.interops[vm.InteropNameToID([]byte("Neo.Storage.Put"))] = s.Put
 	s.interops[vm.InteropNameToID([]byte("Neo.Storage.GetContext"))] = s.GetContext
+	s.interops[vm.InteropNameToID([]byte("Neo.Runtime.Notify"))] = s.Notify
 	return s
 
 }
@@ -89,6 +96,11 @@ func (s *storagePlugin) getInterop(id uint32) *vm.InteropFuncPrice {
 	return nil
 }
 
+func (s *storagePlugin) Notify(v *vm.VM) error {
+	s.events = append(s.events, v.Estack().Pop().Item())
+	return nil
+}
+
 func (s *storagePlugin) Delete(vm *vm.VM) error {
 	vm.Estack().Pop()
 	key := vm.Estack().Pop().Bytes()