From 541da7e83b77a5512656c188f913892b80f6b0d3 Mon Sep 17 00:00:00 2001
From: Anna Shaleva <shaleva.ann@nspcc.ru>
Date: Tue, 11 Apr 2023 18:45:50 +0300
Subject: [PATCH] cli: add `util ops` command

Signed-off-by: Anna Shaleva <shaleva.ann@nspcc.ru>
---
 cli/util/convert.go   | 52 +++++++++++++++++++++++++++++++++++++++++++
 cli/util/util_test.go | 39 ++++++++++++++++++++++++++++++++
 2 files changed, 91 insertions(+)

diff --git a/cli/util/convert.go b/cli/util/convert.go
index 1fb910216..71a1c9547 100644
--- a/cli/util/convert.go
+++ b/cli/util/convert.go
@@ -1,10 +1,14 @@
 package util
 
 import (
+	"encoding/base64"
+	"encoding/hex"
 	"fmt"
+	"os"
 
 	"github.com/nspcc-dev/neo-go/cli/options"
 	vmcli "github.com/nspcc-dev/neo-go/cli/vm"
+	"github.com/nspcc-dev/neo-go/pkg/vm"
 	"github.com/urfave/cli"
 )
 
@@ -44,6 +48,22 @@ func NewCommands() []cli.Command {
 					Action:    txDump,
 					Flags:     txDumpFlags,
 				},
+				{
+					Name:      "ops",
+					Usage:     "Pretty-print VM opcodes of the given base64- or hex- encoded script (base64 is checked first). If the input file is specified, then the script is taken from the file.",
+					UsageText: "ops <base64/hex-encoded script> [-i path-to-file] [--hex]",
+					Action:    handleOps,
+					Flags: []cli.Flag{
+						cli.StringFlag{
+							Name:  "in, i",
+							Usage: "input file containing base64- or hex- encoded script representation",
+						},
+						cli.BoolFlag{
+							Name:  "hex",
+							Usage: "use hex encoding and do not check base64",
+						},
+					},
+				},
 			},
 		},
 	}
@@ -57,3 +77,35 @@ func handleParse(ctx *cli.Context) error {
 	fmt.Fprint(ctx.App.Writer, res)
 	return nil
 }
+
+func handleOps(ctx *cli.Context) error {
+	var (
+		s   string
+		err error
+		b   []byte
+	)
+	in := ctx.String("in")
+	if len(in) != 0 {
+		b, err := os.ReadFile(in)
+		if err != nil {
+			return cli.NewExitError(fmt.Errorf("failed to read file: %w", err), 1)
+		}
+		s = string(b)
+	} else {
+		if !ctx.Args().Present() {
+			return cli.NewExitError("missing script", 1)
+		}
+		s = ctx.Args()[0]
+	}
+	b, err = base64.StdEncoding.DecodeString(s)
+	if err != nil || ctx.Bool("hex") {
+		b, err = hex.DecodeString(s)
+	}
+	if err != nil {
+		return cli.NewExitError("unknown encoding: base64 or hex are supported", 1)
+	}
+	v := vm.New()
+	v.LoadScript(b)
+	v.PrintOps(ctx.App.Writer)
+	return nil
+}
diff --git a/cli/util/util_test.go b/cli/util/util_test.go
index e2f073465..609937fc9 100644
--- a/cli/util/util_test.go
+++ b/cli/util/util_test.go
@@ -1,10 +1,13 @@
 package util_test
 
 import (
+	"os"
+	"path/filepath"
 	"testing"
 
 	"github.com/nspcc-dev/neo-go/internal/testcli"
 	"github.com/nspcc-dev/neo-go/pkg/util"
+	"github.com/stretchr/testify/require"
 )
 
 func TestUtilConvert(t *testing.T) {
@@ -24,3 +27,39 @@ func TestUtilConvert(t *testing.T) {
 	e.CheckNextLine(t, "MDAwMDAwMDAwMDAwMDAwMDAwMDAwMDAwMDAwMDAwMDAwMDAzMDIwMQ==")                         // string to base64
 	e.CheckEOF(t)
 }
+
+func TestUtilOps(t *testing.T) {
+	e := testcli.NewExecutor(t, false)
+	base64Str := "EUA="
+	hexStr := "1140"
+
+	check := func(t *testing.T) {
+		e.CheckNextLine(t, "INDEX.*OPCODE.*PARAMETER")
+		e.CheckNextLine(t, "PUSH1")
+		e.CheckNextLine(t, "RET")
+		e.CheckEOF(t)
+	}
+
+	e.Run(t, "neo-go", "util", "ops", base64Str) // base64
+	check(t)
+
+	e.Run(t, "neo-go", "util", "ops", hexStr) // base64 is checked firstly by default, but it's invalid script if decoded from base64
+	e.CheckNextLine(t, "INDEX.*OPCODE.*PARAMETER")
+	e.CheckNextLine(t, ".*ERROR: incorrect opcode")
+	e.CheckEOF(t)
+
+	e.Run(t, "neo-go", "util", "ops", "--hex", hexStr) // explicitly specify hex encoding
+	check(t)
+
+	e.RunWithError(t, "neo-go", "util", "ops", "%&~*") // unknown encoding
+
+	tmp := filepath.Join(t.TempDir(), "script_base64.txt")
+	require.NoError(t, os.WriteFile(tmp, []byte(base64Str), os.ModePerm))
+	e.Run(t, "neo-go", "util", "ops", "--in", tmp) // base64 from file
+	check(t)
+
+	tmp = filepath.Join(t.TempDir(), "script_hex.txt")
+	require.NoError(t, os.WriteFile(tmp, []byte(hexStr), os.ModePerm))
+	e.Run(t, "neo-go", "util", "ops", "--hex", "--in", tmp) // hex from file
+	check(t)
+}