CHORE: Vendor go-powershell (#2837)

pkg/powershell/middleware/utf8.go

@@ -0,0 +1,49 @@
+// Copyright (c) 2017 Gorillalabs. All rights reserved.
+
+package middleware
+
+import (
+	"encoding/base64"
+	"fmt"
+
+	"github.com/StackExchange/dnscontrol/v4/pkg/powershell/utils"
+)
+
+// utf8 implements a primitive middleware that encodes all outputs
+// as base64 to prevent encoding issues between remote PowerShell
+// shells and the receiver. Just setting $OutputEncoding does not
+// work reliably enough, sadly.
+type utf8 struct {
+	upstream Middleware
+	wrapper  string
+}
+
+func NewUTF8(upstream Middleware) (Middleware, error) {
+	wrapper := "goUTF8" + utils.CreateRandomString(8)
+
+	_, _, err := upstream.Execute(fmt.Sprintf(`function %s { process { if ($_) { [Convert]::ToBase64String([Text.Encoding]::UTF8.GetBytes($_)) } else { '' } } }`, wrapper))
+
+	return &utf8{upstream, wrapper}, err
+}
+
+func (u *utf8) Execute(cmd string) (string, string, error) {
+	// Out-String to concat all lines into a single line,
+	// Write-Host to prevent line breaks at the "window width"
+	cmd = fmt.Sprintf(`%s | Out-String | %s | Write-Host`, cmd, u.wrapper)
+
+	stdout, stderr, err := u.upstream.Execute(cmd)
+	if err != nil {
+		return stdout, stderr, err
+	}
+
+	decoded, err := base64.StdEncoding.DecodeString(stdout)
+	if err != nil {
+		return stdout, stderr, err
+	}
+
+	return string(decoded), stderr, nil
+}
+
+func (u *utf8) Exit() {
+	u.upstream.Exit()
+}