From 64859069ed82d1ccf3f941b43698e5532cfdd9b8 Mon Sep 17 00:00:00 2001
From: 9seconds <nineseconds@yandex.ru>
Date: Tue, 9 Aug 2022 17:43:29 +0300
Subject: [PATCH] Align buildinfo with master

---
 buildinfo.go | 84 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 main.go      | 26 ----------------
 2 files changed, 84 insertions(+), 26 deletions(-)
 create mode 100644 buildinfo.go

diff --git a/buildinfo.go b/buildinfo.go
new file mode 100644
index 000000000..74e6782dd
--- /dev/null
+++ b/buildinfo.go
@@ -0,0 +1,84 @@
+package main
+
+import (
+	"crypto/sha256"
+	"encoding/base64"
+	"encoding/binary"
+	"fmt"
+	"io"
+	"runtime/debug"
+	"sort"
+	"strconv"
+	"time"
+)
+
+var version = "dev" // has to be set by ldflags
+
+const (
+	buildInfoModuleStart byte = iota
+	buildInfoModuleFinish
+	buildInfoModuleDelimeter
+)
+
+func getVersion() string {
+	buildInfo, ok := debug.ReadBuildInfo()
+	if !ok {
+		return version
+	}
+
+	date := time.Now()
+	commit := ""
+	goVersion := buildInfo.GoVersion
+	dirtySuffix := ""
+
+	for _, setting := range buildInfo.Settings {
+		switch setting.Key {
+		case "vcs.time":
+			date, _ = time.Parse(time.RFC3339, setting.Value)
+		case "vcs.revision":
+			commit = setting.Value
+		case "vcs.modified":
+			if dirty, _ := strconv.ParseBool(setting.Value); dirty {
+				dirtySuffix = " [dirty]"
+			}
+		}
+	}
+
+	hasher := sha256.New()
+
+	checksumModule := func(mod *debug.Module) {
+		hasher.Write([]byte{buildInfoModuleStart})
+
+		io.WriteString(hasher, mod.Path) //nolint: errcheck
+		hasher.Write([]byte{buildInfoModuleDelimeter})
+
+		io.WriteString(hasher, mod.Version) //nolint: errcheck
+		hasher.Write([]byte{buildInfoModuleDelimeter})
+
+		io.WriteString(hasher, mod.Sum) //nolint: errcheck
+
+		hasher.Write([]byte{buildInfoModuleFinish})
+	}
+
+	io.WriteString(hasher, buildInfo.Path) //nolint: errcheck
+
+	binary.Write(hasher, binary.LittleEndian, uint64(1+len(buildInfo.Deps))) //nolint: errcheck
+
+	sort.Slice(buildInfo.Deps, func(i, j int) bool {
+		return buildInfo.Deps[i].Path > buildInfo.Deps[j].Path
+	})
+
+	checksumModule(&buildInfo.Main)
+
+	for _, module := range buildInfo.Deps {
+		checksumModule(module)
+	}
+
+	return fmt.Sprintf("%s (%s: %s on %s%s, modules checksum %s)",
+		version,
+		goVersion,
+		date.Format(time.RFC3339),
+		commit,
+		dirtySuffix,
+		base64.StdEncoding.EncodeToString(hasher.Sum(nil)))
+}
diff --git a/main.go b/main.go
index 841556716..7734812b5 100644
--- a/main.go
+++ b/main.go
@@ -3,8 +3,6 @@ package main
 import (
 	"math/rand"
 	"os"
-	"runtime/debug"
-	"strings"
 	"time"
 
 	"github.com/9seconds/mtg/cli"
@@ -12,8 +10,6 @@ import (
 	kingpin "gopkg.in/alecthomas/kingpin.v2"
 )
 
-var version = "dev" // has to be set by ldflags
-
 var (
 	app = kingpin.New("mtg", "Simple MTPROTO proxy.")
 
@@ -161,25 +157,3 @@ func main() {
 		}
 	}
 }
-
-func getVersion() string {
-	if version != "dev" {
-		return version
-	}
-
-	info, ok := debug.ReadBuildInfo()
-	if !ok {
-		return version
-	}
-
-	builder := strings.Builder{}
-	builder.WriteString(info.Main.Version)
-
-	if info.Main.Sum != "" {
-		builder.WriteString(" (checksum: ")
-		builder.WriteString(info.Main.Sum)
-		builder.WriteRune(')')
-	}
-
-	return builder.String()
-}