working commit

vendor/k8s.io/cli-runtime/pkg/printers/terminal.go

@@ -0,0 +1,75 @@
+/*
+Copyright 2022 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package printers
+
+import (
+	"io"
+	"os"
+	"runtime"
+	"strings"
+
+	"github.com/moby/term"
+)
+
+// terminalEscaper replaces ANSI escape sequences and other terminal special
+// characters to avoid terminal escape character attacks (issue #101695).
+var terminalEscaper = strings.NewReplacer("\x1b", "^[", "\r", "\\r")
+
+// WriteEscaped replaces unsafe terminal characters with replacement strings
+// and writes them to the given writer.
+func WriteEscaped(writer io.Writer, output string) error {
+	_, err := terminalEscaper.WriteString(writer, output)
+	return err
+}
+
+// EscapeTerminal escapes terminal special characters in a human readable (but
+// non-reversible) format.
+func EscapeTerminal(in string) string {
+	return terminalEscaper.Replace(in)
+}
+
+// IsTerminal returns whether the passed object is a terminal or not
+func IsTerminal(i interface{}) bool {
+	_, terminal := term.GetFdInfo(i)
+	return terminal
+}
+
+// AllowsColorOutput returns true if the specified writer is a terminal and
+// the process environment indicates color output is supported and desired.
+func AllowsColorOutput(w io.Writer) bool {
+	if !IsTerminal(w) {
+		return false
+	}
+
+	// https://en.wikipedia.org/wiki/Computer_terminal#Dumb_terminals
+	if os.Getenv("TERM") == "dumb" {
+		return false
+	}
+
+	// https://no-color.org/
+	if _, nocolor := os.LookupEnv("NO_COLOR"); nocolor {
+		return false
+	}
+
+	// On Windows WT_SESSION is set by the modern terminal component.
+	// Older terminals have poor support for UTF-8, VT escape codes, etc.
+	if runtime.GOOS == "windows" && os.Getenv("WT_SESSION") == "" {
+		return false
+	}
+
+	return true
+}