kubectl: Move utility functions to util package

`parseFileSource()` and `parseLiteralSource()` are utility functions.
We have a package already for utility functions, `kubectl/util/`.

Move utility functions to `kubectl/util`, capitalize function names to
export from package.

pkg/kubectl/kubectl.go

@@ -18,18 +18,11 @@ limitations under the License.
 package kubectl
 
 import (
-	"errors"
-	"fmt"
-	"path"
 	"strings"
 
 	"k8s.io/apimachinery/pkg/runtime/schema"
 )
 
-const (
-	kubectlAnnotationPrefix = "kubectl.kubernetes.io/"
-)
-
 type NamespaceInfo struct {
 	Namespace string
 }
@@ -188,44 +181,3 @@ func ResourceAliases(rs []string) []string {
 	}
 	return as
 }
-
-// parseFileSource parses the source given. Acceptable formats include:
-//
-// 1.  source-path: the basename will become the key name
-// 2.  source-name=source-path: the source-name will become the key name and source-path is the path to the key file
-//
-// Key names cannot include '='.
-func parseFileSource(source string) (keyName, filePath string, err error) {
-	numSeparators := strings.Count(source, "=")
-	switch {
-	case numSeparators == 0:
-		return path.Base(source), source, nil
-	case numSeparators == 1 && strings.HasPrefix(source, "="):
-		return "", "", fmt.Errorf("key name for file path %v missing.", strings.TrimPrefix(source, "="))
-	case numSeparators == 1 && strings.HasSuffix(source, "="):
-		return "", "", fmt.Errorf("file path for key name %v missing.", strings.TrimSuffix(source, "="))
-	case numSeparators > 1:
-		return "", "", errors.New("Key names or file paths cannot contain '='.")
-	default:
-		components := strings.Split(source, "=")
-		return components[0], components[1], nil
-	}
-}
-
-// parseLiteralSource parses the source key=val pair into its component pieces.
-// This functionality is distinguished from strings.SplitN(source, "=", 2) since
-// it returns an error in the case of empty keys, values, or a missing equals
-// sign.
-func parseLiteralSource(source string) (keyName, value string, err error) {
-	// leading equal is invalid
-	if strings.Index(source, "=") == 0 {
-		return "", "", fmt.Errorf("invalid literal source %v, expected key=value", source)
-	}
-	// split after the first equal (so values can have the = character)
-	items := strings.SplitN(source, "=", 2)
-	if len(items) != 2 {
-		return "", "", fmt.Errorf("invalid literal source %v, expected key=value", source)
-	}
-
-	return items[0], items[1], nil
-}