Inline shellescape dependency

Signed-off-by: William Martin <williammartin@github.com>

shellescape/LICENSE

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+The MIT License (MIT)
+
+Copyright (c) 2016 Alessio Treglia
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

shellescape/shellescape.go

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+/*
+Package shellescape provides the shellescape.Quote to escape arbitrary
+strings for a safe use as command line arguments in the most common
+POSIX shells.
+
+The original Python package which this work was inspired by can be found
+at https://pypi.python.org/pypi/shellescape.
+
+Portions of this file are from al.essio.dev/pkg/shellescape, © 2016 Alessio Treglia under the MIT License.
+See LICENSE for more information.
+*/
+package shellescape
+
+/*
+The functionality provided by shellescape.Quote could be helpful
+in those cases where it is known that the output of a Go program will
+be appended to/used in the context of shell programs' command line arguments.
+*/
+
+import (
+	"regexp"
+	"strings"
+)
+
+var pattern *regexp.Regexp = regexp.MustCompile(`[^\w@%+=:,./-]`)
+
+// Quote returns a shell-escaped version of the string s. The returned value
+// is a string that can safely be used as one token in a shell command line.
+func Quote(s string) string {
+	if len(s) == 0 {
+		return "''"
+	}
+
+	if pattern.MatchString(s) {
+		return "'" + strings.ReplaceAll(s, "'", "'\"'\"'") + "'"
+	}
+
+	return s
+}

shellescape/shellescape_test.go

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+package shellescape_test
+
+import (
+	"testing"
+
+	"github.com/zalando/go-keyring/shellescape"
+)
+
+func assertEqual(t *testing.T, s, expected string) {
+	if s != expected {
+		t.Fatalf("%q (expected: %q)", s, expected)
+	}
+}
+
+func TestEmptyString(t *testing.T) {
+	s := shellescape.Quote("")
+	expected := "''"
+	if s != expected {
+		t.Errorf("Expected escaped string %s, got: %s", expected, s)
+	}
+}
+
+func TestDoubleQuotedString(t *testing.T) {
+	s := shellescape.Quote(`"double quoted"`)
+	expected := `'"double quoted"'`
+	if s != expected {
+		t.Errorf("Expected escaped string %s, got: %s", expected, s)
+	}
+}
+
+func TestSingleQuotedString(t *testing.T) {
+	s := shellescape.Quote(`'single quoted'`)
+	expected := `''"'"'single quoted'"'"''`
+	if s != expected {
+		t.Errorf("Expected escaped string %s, got: %s", expected, s)
+	}
+}
+
+func TestUnquotedString(t *testing.T) {
+	s := shellescape.Quote(`no quotes`)
+	expected := `'no quotes'`
+	if s != expected {
+		t.Errorf("Expected escaped string %s, got: %s", expected, s)
+	}
+}
+
+func TestSingleInvalid(t *testing.T) {
+	s := shellescape.Quote(`;`)
+	expected := `';'`
+	if s != expected {
+		t.Errorf("Expected escaped string %s, got: %s", expected, s)
+	}
+}
+
+func TestAllInvalid(t *testing.T) {
+	s := shellescape.Quote(`;${}`)
+	expected := `';${}'`
+	if s != expected {
+		t.Errorf("Expected escaped string %s, got: %s", expected, s)
+	}
+}
+
+func TestCleanString(t *testing.T) {
+	s := shellescape.Quote("foo.example.com")
+	expected := `foo.example.com`
+	if s != expected {
+		t.Errorf("Expected escaped string %s, got: %s", expected, s)
+	}
+}